agora inbox for [email protected]  

help / color / mirror / Atom feed

[PATCH v44b 4/4] hack deadlock detector
414+ messages / 2 participants
[nested] [flat]

* [PATCH v44b 4/4] hack deadlock detector
@ 2026-03-25 19:35  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Álvaro Herrera @ 2026-03-25 19:35 UTC (permalink / raw)

---
 src/backend/commands/cluster.c                | 10 +++
 src/backend/storage/lmgr/deadlock.c           | 12 +++
 src/include/storage/proc.h                    |  1 +
 src/test/modules/injection_points/Makefile    |  1 +
 .../expected/repack_deadlock.out              | 63 ++++++++++++++
 src/test/modules/injection_points/meson.build |  1 +
 .../specs/repack_deadlock.spec                | 83 +++++++++++++++++++
 7 files changed, 171 insertions(+)
 create mode 100644 src/test/modules/injection_points/expected/repack_deadlock.out
 create mode 100644 src/test/modules/injection_points/specs/repack_deadlock.spec

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 2c3058ba10d..d5b1dfbff69 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -372,6 +372,16 @@ ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel)
 	/* Determine the lock mode to use. */
 	lockmode = RepackLockLevel((params.options & CLUOPT_CONCURRENT) != 0);
 
+	/*
+	 * If in concurrent mode, set the PROC_IN_CONCURRENT_REPACK flag.  This
+	 * makes the deadlock checker cause anyone that would conflict with us
+	 * to error out.  It's important to set this flag ahead of actually locking
+	 * the relation; it won't of course affect anyone until we do have a lock
+	 * that others can conflict with.
+	 */
+	if ((params.options & CLUOPT_CONCURRENT) != 0)
+		MyProc->statusFlags |= PROC_IN_CONCURRENT_REPACK;
+
 	/*
 	 * If a single relation is specified, process it and we're done ... unless
 	 * the relation is a partitioned table, in which case we fall through.
diff --git a/src/backend/storage/lmgr/deadlock.c b/src/backend/storage/lmgr/deadlock.c
index b8962d875b6..10266e384aa 100644
--- a/src/backend/storage/lmgr/deadlock.c
+++ b/src/backend/storage/lmgr/deadlock.c
@@ -620,6 +620,18 @@ FindLockCycleRecurseMember(PGPROC *checkProc,
 						proc->statusFlags & PROC_IS_AUTOVACUUM)
 						blocking_autovacuum_proc = proc;
 
+					/*
+					 * If we note that we're blocked by some process running
+					 * REPACK (CONCURRENTLY), just fail.  That process is
+					 * going to upgrade its lock at some point, and it would
+					 * be inappropriate for any other process to cause that
+					 * to fail.
+					 */
+					if (checkProc == MyProc &&
+						proc->statusFlags & PROC_IN_CONCURRENT_REPACK)
+						/* not a serious error message proposal */
+						elog(ERROR, "oops, we're blocked by REPACK, time to die");
+
 					/* We're done looking at this proclock */
 					break;
 				}
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 1dad125706e..4e340ead455 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -69,6 +69,7 @@ struct XidCache
 #define		PROC_AFFECTS_ALL_HORIZONS	0x20	/* this proc's xmin must be
 												 * included in vacuum horizons
 												 * in all databases */
+#define		PROC_IN_CONCURRENT_REPACK	0x40	/* REPACK (CONCURRENTLY) */
 
 /* flags reset at EOXact */
 #define		PROC_VACUUM_STATE_MASK \
diff --git a/src/test/modules/injection_points/Makefile b/src/test/modules/injection_points/Makefile
index 2cd7d87c533..f7663859fe2 100644
--- a/src/test/modules/injection_points/Makefile
+++ b/src/test/modules/injection_points/Makefile
@@ -15,6 +15,7 @@ REGRESS_OPTS = --dlpath=$(top_builddir)/src/test/regress
 ISOLATION = basic \
 	    inplace \
 	    repack \
+	    repack_deadlock \
 	    repack_toast \
 	    syscache-update-pruned \
 	    heap_lock_update
diff --git a/src/test/modules/injection_points/expected/repack_deadlock.out b/src/test/modules/injection_points/expected/repack_deadlock.out
new file mode 100644
index 00000000000..42505d10933
--- /dev/null
+++ b/src/test/modules/injection_points/expected/repack_deadlock.out
@@ -0,0 +1,63 @@
+Parsed test spec with 2 sessions
+
+starting permutation: wait_before_lock add_column wakeup_before_lock check1
+injection_points_attach
+-----------------------
+                       
+(1 row)
+
+step wait_before_lock: 
+	REPACK (CONCURRENTLY) repack_deadlock USING INDEX repack_deadlock_pkey;
+ <waiting ...>
+step add_column: 
+	alter table repack_deadlock add column noise text;
+ <waiting ...>
+step add_column: <... completed>
+ERROR:  oops, we're blocked by REPACK, time to die
+step wakeup_before_lock: 
+	SELECT injection_points_wakeup('repack-concurrently-before-lock');
+
+injection_points_wakeup
+-----------------------
+                       
+(1 row)
+
+step wait_before_lock: <... completed>
+step check1: 
+	INSERT INTO relfilenodes(node)
+	SELECT relfilenode FROM pg_class WHERE relname='repack_deadlock';
+
+	SELECT count(DISTINCT node) FROM relfilenodes;
+
+	SELECT i, j FROM repack_deadlock ORDER BY i, j;
+
+	INSERT INTO data_s1(i, j)
+	SELECT i, j FROM repack_deadlock;
+
+	SELECT count(*)
+	FROM data_s1 d1 FULL JOIN data_s2 d2 USING (i, j)
+	WHERE d1.i ISNULL OR d2.i ISNULL;
+
+count
+-----
+    1
+(1 row)
+
+i|j
+-+-
+1|1
+2|2
+3|3
+4|4
+(4 rows)
+
+count
+-----
+    4
+(1 row)
+
+injection_points_detach
+-----------------------
+                       
+(1 row)
+
diff --git a/src/test/modules/injection_points/meson.build b/src/test/modules/injection_points/meson.build
index a414abb924b..1cd88d6db65 100644
--- a/src/test/modules/injection_points/meson.build
+++ b/src/test/modules/injection_points/meson.build
@@ -46,6 +46,7 @@ tests += {
       'basic',
       'inplace',
       'repack',
+      'repack_deadlock',
       'repack_toast',
       'syscache-update-pruned',
       'heap_lock_update',
diff --git a/src/test/modules/injection_points/specs/repack_deadlock.spec b/src/test/modules/injection_points/specs/repack_deadlock.spec
new file mode 100644
index 00000000000..9d23a6588c2
--- /dev/null
+++ b/src/test/modules/injection_points/specs/repack_deadlock.spec
@@ -0,0 +1,83 @@
+# Test REPACK with a concurrent transaction that would cause a deadlock
+setup
+{
+	CREATE EXTENSION injection_points;
+
+	CREATE TABLE repack_deadlock(i int PRIMARY KEY, j int);
+	INSERT INTO repack_deadlock(i, j) VALUES (1, 1), (2, 2), (3, 3), (4, 4);
+
+	CREATE TABLE relfilenodes(node oid);
+
+	CREATE TABLE data_s1(i int, j int);
+	CREATE TABLE data_s2(i int, j int);
+}
+
+teardown
+{
+	DROP TABLE repack_deadlock;
+	DROP EXTENSION injection_points;
+
+	DROP TABLE relfilenodes;
+	DROP TABLE data_s1;
+	DROP TABLE data_s2;
+}
+
+session s1
+setup
+{
+	SELECT injection_points_set_local();
+	SELECT injection_points_attach('repack-concurrently-before-lock', 'wait');
+}
+# Perform the initial load and wait for s2 to do some data changes.
+step wait_before_lock
+{
+	REPACK (CONCURRENTLY) repack_deadlock USING INDEX repack_deadlock_pkey;
+}
+# Check the table from the perspective of s1.
+#
+# Besides the contents, we also check that relfilenode has changed.
+
+# Have each session write the contents into a table and use FULL JOIN to check
+# if the outputs are identical.
+step check1
+{
+	INSERT INTO relfilenodes(node)
+	SELECT relfilenode FROM pg_class WHERE relname='repack_deadlock';
+
+	SELECT count(DISTINCT node) FROM relfilenodes;
+
+	SELECT i, j FROM repack_deadlock ORDER BY i, j;
+
+	INSERT INTO data_s1(i, j)
+	SELECT i, j FROM repack_deadlock;
+
+	SELECT count(*)
+	FROM data_s1 d1 FULL JOIN data_s2 d2 USING (i, j)
+	WHERE d1.i ISNULL OR d2.i ISNULL;
+}
+teardown
+{
+	SELECT injection_points_detach('repack-concurrently-before-lock');
+}
+
+session s2
+# Change the existing data. UPDATE changes both key and non-key columns. Also
+# update one row twice to test whether tuple version generated by this session
+# can be found.
+step add_column
+{
+	alter table repack_deadlock add column noise text;
+}
+
+step wakeup_before_lock
+{
+	SELECT injection_points_wakeup('repack-concurrently-before-lock');
+}
+
+# Test if data changes introduced while one session is performing REPACK
+# CONCURRENTLY find their way into the table.
+permutation
+	wait_before_lock
+	add_column
+	wakeup_before_lock
+	check1
-- 
2.47.3


--fot5plqmb33ey33c--





^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread

* [PATCH 5/8] Simplify the way restrictions are imposed on index functions.
@ 2026-06-16 11:54  Antonin Houska <[email protected]>
  0 siblings, 0 replies; 414+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

Whenever we expect possible execution of index functions, we need to make sure
that they execute with the appropriate privileges. Also, the core should not
see (and use) values of GUC parameters introduced by the index functions.

This patch introduces functions enable_index_build_security() and
disable_index_build_security() which make the security measures less
verbose. It's needed for the upcoming enhancements of REPACK (CONCURRENTLY),
but looks like useful refactoring anyway.
---
 src/backend/access/brin/brin.c   | 32 ++++----------
 src/backend/catalog/index.c      | 72 ++++++++++++++++++--------------
 src/backend/commands/analyze.c   | 21 +++-------
 src/backend/commands/indexcmds.c | 49 +++++++---------------
 src/backend/commands/repack.c    | 24 +++--------
 src/backend/commands/tablecmds.c | 24 +++--------
 src/backend/commands/vacuum.c    | 23 +++-------
 src/include/catalog/index.h      | 10 +++++
 src/tools/pgindent/typedefs.list |  1 +
 9 files changed, 95 insertions(+), 161 deletions(-)

diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index bdb30752e09..2359bffa518 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -1391,10 +1391,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 	Oid			heapoid;
 	Relation	indexRel;
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	double		numSummarized = 0;
+	IndexBuildSecurity ibsec;
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -1420,27 +1418,12 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 		heapRel = table_open(heapoid, ShareUpdateExclusiveLock);
 
 		/*
-		 * Autovacuum calls us.  For its benefit, switch to the table owner's
-		 * userid, so that any index functions are run as that user.  Also
-		 * lock down security-restricted operations and arrange to make GUC
-		 * variable changes local to this command.  This is harmless, albeit
-		 * unnecessary, when called from SQL, because we fail shortly if the
-		 * user does not own the index.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 	}
 	else
-	{
 		heapRel = NULL;
-		/* Set these just to suppress "uninitialized variable" warnings */
-		save_userid = InvalidOid;
-		save_sec_context = -1;
-		save_nestlevel = -1;
-	}
 
 	indexRel = index_open(indexoid, ShareUpdateExclusiveLock);
 
@@ -1453,7 +1436,8 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 						RelationGetRelationName(indexRel))));
 
 	/* User must own the index (comparable to privileges needed for VACUUM) */
-	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid, save_userid))
+	if (heapRel != NULL && !object_ownercheck(RelationRelationId, indexoid,
+											  ibsec.userid))
 		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_INDEX,
 					   RelationGetRelationName(indexRel));
 
@@ -1477,11 +1461,9 @@ brin_summarize_range(PG_FUNCTION_ARGS)
 				 errmsg("index \"%s\" is not valid",
 						RelationGetRelationName(indexRel))));
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
 
 	index_close(indexRel, ShareUpdateExclusiveLock);
 	table_close(heapRel, ShareUpdateExclusiveLock);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..fa5a53d04ff 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1504,11 +1504,9 @@ index_concurrently_build(Oid heapRelationId,
 						 Oid indexRelationId)
 {
 	Relation	heapRel;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	Relation	indexRelation;
 	IndexInfo  *indexInfo;
+	IndexBuildSecurity ibsec;
 
 	/* This had better make sure that a snapshot is active */
 	Assert(ActiveSnapshotSet());
@@ -1517,15 +1515,9 @@ index_concurrently_build(Oid heapRelationId,
 	heapRel = table_open(heapRelationId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexRelationId, RowExclusiveLock);
 
@@ -1542,11 +1534,8 @@ index_concurrently_build(Oid heapRelationId,
 	/* Now build the index */
 	index_build(heapRel, indexRelation, indexInfo, false, true, true);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close both the relations, but keep the locks */
 	table_close(heapRel, NoLock);
@@ -3375,9 +3364,7 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	IndexInfo  *indexInfo;
 	IndexVacuumInfo ivinfo;
 	ValidateIndexState state;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	{
 		const int	progress_index[] = {
@@ -3399,15 +3386,9 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	heapRelation = table_open(heapId, ShareUpdateExclusiveLock);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(heapRelation->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(heapRelation->rd_rel->relowner, &ibsec);
 
 	indexRelation = index_open(indexId, RowExclusiveLock);
 
@@ -3486,11 +3467,8 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 		 "validate_index found %.0f heap tuples, %.0f index tuples; inserted %.0f missing tuples",
 		 state.htups, state.itups, state.tups_inserted);
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Close rels, but keep locks */
 	index_close(indexRelation, NoLock);
@@ -4115,6 +4093,36 @@ reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 	return result;
 }
 
+/*
+ * Before building an index, witch to the table owner's userid, so that any
+ * index functions are run as that user. Also lock down security-restricted
+ * operations and arrange to make GUC variable changes local to this command.
+ *
+ * Information needed later by disable_index_build_security() is stored in
+ * *sec.
+ */
+void
+enable_index_build_security(Oid userid, IndexBuildSecurity *sec)
+{
+	GetUserIdAndSecContext(&sec->userid, &sec->sec_context);
+	SetUserIdAndSecContext(userid,
+						   sec->sec_context | SECURITY_RESTRICTED_OPERATION);
+	sec->nestlevel = NewGUCNestLevel();
+	RestrictSearchPath();
+}
+
+/*
+ * Undo what enable_index_build_security() did.
+ */
+void
+disable_index_build_security(IndexBuildSecurity *sec)
+{
+	/* Roll back any GUC changes executed by index functions */
+	AtEOXact_GUC(false, sec->nestlevel);
+
+	/* Restore userid and security context */
+	SetUserIdAndSecContext(sec->userid, sec->sec_context);
+}
 
 /* ----------------------------------------------------------------
  *		System index reindexing support
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f66e80b757c..dc2ad77ef9a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -328,14 +328,12 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	MemoryContext caller_context;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	WalUsage	startwalusage = pgWalUsage;
 	BufferUsage startbufferusage = pgBufferUsage;
 	BufferUsage bufferusage;
 	PgStat_Counter startreadtime = 0;
 	PgStat_Counter startwritetime = 0;
+	IndexBuildSecurity ibsec;
 
 	verbose = (params->options & VACOPT_VERBOSE) != 0;
 	instrument = (verbose || (AmAutoVacuumWorkerProcess() &&
@@ -361,15 +359,9 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 	caller_context = MemoryContextSwitchTo(anl_context);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(onerel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(onerel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * When verbose or autovacuum logging is used, initialize a resource usage
@@ -858,11 +850,8 @@ do_analyze_rel(Relation onerel, const VacuumParams *params,
 		}
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* Restore current context and release memory */
 	MemoryContextSwitchTo(caller_context);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..2af586669ae 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -689,6 +689,8 @@ DefineIndex(ParseState *pstate,
 	 * Switch to the table owner's userid, so that any index functions are run
 	 * as that user.  Also lock down security-restricted operations.  We
 	 * already arranged to make GUC variable changes local to this command.
+	 *
+	 * XXX Use enable_index_build_security()?
 	 */
 	GetUserIdAndSecContext(&root_save_userid, &root_save_sec_context);
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
@@ -1376,22 +1378,16 @@ DefineIndex(ParseState *pstate,
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;
-				Oid			child_save_userid;
-				int			child_save_sec_context;
-				int			child_save_nestlevel;
 				List	   *childidxs;
 				ListCell   *cell;
 				AttrMap    *attmap;
 				bool		found = false;
+				IndexBuildSecurity child_ibsec;
 
 				childrel = table_open(childRelid, lockmode);
 
-				GetUserIdAndSecContext(&child_save_userid,
-									   &child_save_sec_context);
-				SetUserIdAndSecContext(childrel->rd_rel->relowner,
-									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
-				child_save_nestlevel = NewGUCNestLevel();
-				RestrictSearchPath();
+				enable_index_build_security(childrel->rd_rel->relowner,
+											&child_ibsec);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -1408,9 +1404,7 @@ DefineIndex(ParseState *pstate,
 								 errdetail("Table \"%s\" contains partitions that are foreign tables.",
 										   RelationGetRelationName(rel))));
 
-					AtEOXact_GUC(false, child_save_nestlevel);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					disable_index_build_security(&child_ibsec);
 					table_close(childrel, lockmode);
 					continue;
 				}
@@ -1495,9 +1489,7 @@ DefineIndex(ParseState *pstate,
 				}
 
 				list_free(childidxs);
-				AtEOXact_GUC(false, child_save_nestlevel);
-				SetUserIdAndSecContext(child_save_userid,
-									   child_save_sec_context);
+				disable_index_build_security(&child_ibsec);
 				table_close(childrel, NoLock);
 
 				/*
@@ -1524,7 +1516,7 @@ DefineIndex(ParseState *pstate,
 					 * Recurse as the starting user ID.  Callee will use that
 					 * for permission checks, then switch again.
 					 */
-					Assert(GetUserId() == child_save_userid);
+					Assert(GetUserId() == child_ibsec.userid);
 					SetUserIdAndSecContext(root_save_userid,
 										   root_save_sec_context);
 					childAddr =
@@ -1537,8 +1529,8 @@ DefineIndex(ParseState *pstate,
 									is_alter_table, check_rights,
 									check_not_in_use,
 									skip_build, quiet);
-					SetUserIdAndSecContext(child_save_userid,
-										   child_save_sec_context);
+					SetUserIdAndSecContext(child_ibsec.userid,
+										   child_ibsec.sec_context);
 
 					/*
 					 * Check if the index just created is valid or not, as it
@@ -3926,27 +3918,19 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		Oid			newIndexId;
 		Relation	indexRel;
 		Relation	heapRel;
-		Oid			save_userid;
-		int			save_sec_context;
-		int			save_nestlevel;
 		Relation	newIndexRel;
 		LockRelId  *lockrelid;
 		Oid			tablespaceid;
+		IndexBuildSecurity ibsec;
 
 		indexRel = index_open(idx->indexId, ShareUpdateExclusiveLock);
 		heapRel = table_open(indexRel->rd_index->indrelid,
 							 ShareUpdateExclusiveLock);
 
 		/*
-		 * Switch to the table owner's userid, so that any index functions are
-		 * run as that user.  Also lock down security-restricted operations
-		 * and arrange to make GUC variable changes local to this command.
+		 * Prevent index functions from doing what they are not supposed to.
 		 */
-		GetUserIdAndSecContext(&save_userid, &save_sec_context);
-		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
-							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-		save_nestlevel = NewGUCNestLevel();
-		RestrictSearchPath();
+		enable_index_build_security(heapRel->rd_rel->relowner, &ibsec);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (RelationGetIndexExpressions(indexRel) == NIL &&
@@ -4034,11 +4018,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		index_close(indexRel, NoLock);
 		index_close(newIndexRel, NoLock);
 
-		/* Roll back any GUC changes executed by index functions */
-		AtEOXact_GUC(false, save_nestlevel);
-
-		/* Restore userid and security context */
-		SetUserIdAndSecContext(save_userid, save_sec_context);
+		/* Relax the restrictions imposed above. */
+		disable_index_build_security(&ibsec);
 
 		table_close(heapRel, NoLock);
 
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 2debadd86ed..28b34fd4387 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -503,13 +503,11 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	Oid			tableOid = RelationGetRelid(OldHeap);
 	Relation	index;
 	LOCKMODE	lmode;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	bool		verbose = ((params->options & CLUOPT_VERBOSE) != 0);
 	bool		recheck = ((params->options & CLUOPT_RECHECK) != 0);
 	bool		concurrent = ((params->options & CLUOPT_CONCURRENT) != 0);
 	Oid			ident_idx = InvalidOid;
+	IndexBuildSecurity ibsec;
 
 	/* Determine the lock mode to use. */
 	lmode = RepackLockLevel(concurrent);
@@ -528,15 +526,9 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	pgstat_progress_update_param(PROGRESS_REPACK_COMMAND, cmd);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(OldHeap->rd_rel->relowner, &ibsec);
 
 	/*
 	 * Recheck that the relation is still what it was when we started.
@@ -546,7 +538,7 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 	 * not-previously-clustered index.
 	 */
 	if (recheck &&
-		!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid,
+		!cluster_rel_recheck(cmd, OldHeap, indexOid, GetUserId(),
 							 lmode, params->options))
 		goto out;
 
@@ -670,11 +662,8 @@ cluster_rel(RepackCommand cmd, Relation OldHeap, Oid indexOid,
 		rebuild_relation(OldHeap, index, verbose, ident_idx);
 
 out:
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	pgstat_progress_end_command();
 }
@@ -1207,7 +1196,6 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose,
 	}
 }
 
-
 /*
  * Create the transient table that will be filled with new data during
  * CLUSTER, ALTER TABLE, and similar operations.  The transient table
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 38f9ffcd04f..c0f6217caa6 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -23245,9 +23245,7 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	Oid			defaultPartOid;
 	Oid			existingRelid;
 	Oid			ownerId = InvalidOid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * Check ownership of merged partitions - partitions with different owners
@@ -23379,18 +23377,9 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	newPartRel = createPartitionTable(wqueue, cmd->name, rel, ownerId);
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also, lockdown security-restricted operations and
-	 * arrange to make GUC variable changes local to this command.
-	 *
-	 * Need to do it after determining the namespace in the
-	 * createPartitionTable() call.
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(ownerId,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(ownerId, &ibsec);
 
 	/* Copy data from merged partitions to the new partition. */
 	MergePartitionsMoveRows(wqueue, mergingPartitions, newPartRel);
@@ -23427,11 +23416,8 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/* Keep the lock until commit. */
 	table_close(newPartRel, NoLock);
 
-	/* Roll back any GUC changes executed by index functions. */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore the userid and security context. */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 }
 
 /*
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index a4abb29cf64..8922d713916 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -34,6 +34,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -2017,10 +2018,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 	LockRelId	lockrelid;
 	Oid			priv_relid;
 	Oid			toast_relid;
-	Oid			save_userid;
-	int			save_sec_context;
-	int			save_nestlevel;
 	VacuumParams toast_vacuum_params;
+	IndexBuildSecurity ibsec;
 
 	/*
 	 * This function scribbles on the parameters, so make a copy early to
@@ -2270,16 +2269,9 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 		toast_relid = InvalidOid;
 
 	/*
-	 * Switch to the table owner's userid, so that any index functions are run
-	 * as that user.  Also lock down security-restricted operations and
-	 * arrange to make GUC variable changes local to this command. (This is
-	 * unnecessary, but harmless, for lazy VACUUM.)
+	 * Prevent index functions from doing what they are not supposed to.
 	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(rel->rd_rel->relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-	save_nestlevel = NewGUCNestLevel();
-	RestrictSearchPath();
+	enable_index_build_security(rel->rd_rel->relowner, &ibsec);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main
@@ -2310,11 +2302,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
 			table_relation_vacuum(rel, &params, bstrategy);
 	}
 
-	/* Roll back any GUC changes executed by index functions */
-	AtEOXact_GUC(false, save_nestlevel);
-
-	/* Restore userid and security context */
-	SetUserIdAndSecContext(save_userid, save_sec_context);
+	/* Relax the restrictions imposed above. */
+	disable_index_build_security(&ibsec);
 
 	/* all done with this class, but hold lock until commit */
 	if (rel)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 9aee8226347..dd9ae8119e5 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -172,6 +172,16 @@ extern void reindex_index(const ReindexStmt *stmt, Oid indexId,
 extern bool reindex_relation(const ReindexStmt *stmt, Oid relid, int flags,
 							 const ReindexParams *params);
 
+typedef struct IndexBuildSecurity
+{
+	Oid			userid;
+	int			sec_context;
+	int			nestlevel;
+} IndexBuildSecurity;
+
+extern void enable_index_build_security(Oid userid, IndexBuildSecurity *sec);
+extern void disable_index_build_security(IndexBuildSecurity *sec);
+
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b4d5abbaca7..90234c3f736 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1325,6 +1325,7 @@ IndexAttachInfo
 IndexAttrBitmapKind
 IndexBuildCallback
 IndexBuildResult
+IndexBuildSecurity
 IndexBulkDeleteCallback
 IndexBulkDeleteResult
 IndexClause
-- 
2.52.0


--=-=-=
Content-Type: text/x-diff
Content-Disposition: attachment;
 filename=v01-0006-Use-separate-transactions-for-catalog-changes.patch



^ permalink  raw  reply  [nested|flat] 414+ messages in thread