pg.ddx.io pgsql-general@postgresql.org mailing list archive help / color / mirror / Atom feed From: Nathan Bossart <nathan@postgresql.org>
Subject: [PATCH 1/1] pg_prewarm privilege test
Date: Thu, 9 Oct 2025 15:49:18 -0500
---
contrib/pg_prewarm/pg_prewarm.c | 83 +++++++++++++++++++++++++++++--
contrib/pg_prewarm/t/001_basic.pl | 36 +++++++++++++-
2 files changed, 113 insertions(+), 6 deletions(-)
diff --git a/contrib/pg_prewarm/pg_prewarm.c b/contrib/pg_prewarm/pg_prewarm.c
index b968933ea8b..57b720cfbed 100644
--- a/contrib/pg_prewarm/pg_prewarm.c
+++ b/contrib/pg_prewarm/pg_prewarm.c
@@ -16,13 +16,17 @@
#include <unistd.h>
#include "access/relation.h"
+#include "catalog/index.h"
#include "fmgr.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
+#include "storage/lmgr.h"
#include "storage/read_stream.h"
+#include "storage/sinval.h"
#include "storage/smgr.h"
#include "utils/acl.h"
#include "utils/builtins.h"
+#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
@@ -42,6 +46,74 @@ typedef enum
static PGIOAlignedBlock blockbuffer;
+static void
+check_privs_and_lock_rel(Oid relid, Oid *heaprel)
+{
+ uint64 inval_count;
+ Oid privOid = InvalidOid;
+
+ do
+ {
+ AclResult aclresult;
+ bool is_missing = false;
+ char relkind;
+
+ /*
+ * Remember this value so that, after locking the relation(s), we can
+ * check whether any invalidation messages have been processed that
+ * might require a do-over.
+ */
+ inval_count = SharedInvalidMessageCounter;
+
+ /*
+ * Unlock any previously-locked relations. We could try to hold onto
+ * these through iterations, but it's simpler to just start fresh each
+ * time.
+ */
+ if (OidIsValid(privOid))
+ {
+ if (privOid != relid)
+ UnlockRelationOid(privOid, AccessShareLock);
+ UnlockRelationOid(relid, AccessShareLock);
+ }
+
+ /*
+ * For indexes, privilege checks must happen on the heap relation.
+ */
+ relkind = get_rel_relkind(relid);
+ if (relkind == RELKIND_INDEX || relkind == RELKIND_PARTITIONED_INDEX)
+ privOid = IndexGetRelation(relid, false);
+ else
+ privOid = relid;
+
+ /*
+ * Check privileges. If the relation has gone missing, there's
+ * nothing for us to do. We'll either retry in the next loop
+ * iteration, or the caller will fail when it tries to open the
+ * relation.
+ */
+ aclresult = pg_class_aclcheck_ext(privOid, GetUserId(),
+ ACL_SELECT, &is_missing);
+ if (!is_missing && aclresult != ACLCHECK_OK)
+ aclcheck_error(aclresult,
+ get_relkind_objtype(relkind),
+ get_rel_name(relid));
+
+ /*
+ * Lock the relation(s). If relid is an index, make sure we lock its
+ * heap first. Note that we rely on LockRelationOid() to call
+ * AcceptInvalidationMessages().
+ */
+ if (privOid != relid)
+ LockRelationOid(privOid, AccessShareLock);
+ LockRelationOid(relid, AccessShareLock);
+
+ } while (inval_count != SharedInvalidMessageCounter);
+
+ if (privOid != relid)
+ *heaprel = privOid;
+}
+
/*
* pg_prewarm(regclass, mode text, fork text,
* first_block int8, last_block int8)
@@ -70,7 +142,7 @@ pg_prewarm(PG_FUNCTION_ARGS)
char *forkString;
char *ttype;
PrewarmType ptype;
- AclResult aclresult;
+ Oid heaprel = InvalidOid;
/* Basic sanity checking. */
if (PG_ARGISNULL(0))
@@ -107,10 +179,8 @@ pg_prewarm(PG_FUNCTION_ARGS)
forkNumber = forkname_to_number(forkString);
/* Open relation and check privileges. */
- rel = relation_open(relOid, AccessShareLock);
- aclresult = pg_class_aclcheck(relOid, GetUserId(), ACL_SELECT);
- if (aclresult != ACLCHECK_OK)
- aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind), get_rel_name(relOid));
+ check_privs_and_lock_rel(relOid, &heaprel);
+ rel = relation_open(relOid, NoLock);
/* Check that the relation has storage. */
if (!RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
@@ -236,5 +306,8 @@ pg_prewarm(PG_FUNCTION_ARGS)
/* Close relation, release lock. */
relation_close(rel, AccessShareLock);
+ if (OidIsValid(heaprel))
+ UnlockRelationOid(heaprel, AccessShareLock);
+
PG_RETURN_INT64(blocks_done);
}
diff --git a/contrib/pg_prewarm/t/001_basic.pl b/contrib/pg_prewarm/t/001_basic.pl
index 0a8259d3678..5d7010eb44e 100644
--- a/contrib/pg_prewarm/t/001_basic.pl
+++ b/contrib/pg_prewarm/t/001_basic.pl
@@ -23,7 +23,9 @@ $node->start;
$node->safe_psql("postgres",
"CREATE EXTENSION pg_prewarm;\n"
. "CREATE TABLE test(c1 int);\n"
- . "INSERT INTO test SELECT generate_series(1, 100);");
+ . "INSERT INTO test SELECT generate_series(1, 100);\n"
+ . "CREATE INDEX test_idx ON test(c1);\n"
+ . "CREATE ROLE test_user LOGIN;");
# test read mode
my $result =
@@ -42,6 +44,38 @@ ok( ( $stdout =~ qr/^[1-9][0-9]*$/
or $stderr =~ qr/prefetch is not supported by this build/),
'prefetch mode succeeded');
+# test_user should be unable to prewarm table/index without privileges
+($cmdret, $stdout, $stderr) =
+ $node->psql(
+ "postgres", "SELECT pg_prewarm('test');",
+ extra_params => [ '--username' => 'test_user' ]);
+ok($stderr =~ /permission denied for table test/, 'pg_prewarm failed as expected');
+($cmdret, $stdout, $stderr) =
+ $node->psql(
+ "postgres", "SELECT pg_prewarm('test_idx');",
+ extra_params => [ '--username' => 'test_user' ]);
+ok($stderr =~ /permission denied for index test_idx/, 'pg_prewarm failed as expected');
+
+# test_user should be able to prewarm table/index with privileges
+$node->safe_psql("postgres", "GRANT SELECT ON test TO test_user;");
+$result =
+ $node->safe_psql(
+ "postgres", "SELECT pg_prewarm('test');",
+ extra_params => [ '--username' => 'test_user' ]);
+like($result, qr/^[1-9][0-9]*$/, 'pg_prewarm succeeded as expected');
+$result =
+ $node->safe_psql(
+ "postgres", "SELECT pg_prewarm('test_idx');",
+ extra_params => [ '--username' => 'test_user' ]);
+like($result, qr/^[1-9][0-9]*$/, 'pg_prewarm succeeded as expected');
+
+# prewarm fails for nonexistent table
+($cmdret, $stdout, $stderr) =
+ $node->psql(
+ "postgres", "SELECT pg_prewarm(0);",
+ extra_params => [ '--username' => 'test_user' ]);
+ok($stderr =~ /could not open relation with OID 0/, 'pg_prewarm failed as expected');
+
# test autoprewarm_dump_now()
$result = $node->safe_psql("postgres", "SELECT autoprewarm_dump_now();");
like($result, qr/^[1-9][0-9]*$/, 'autoprewarm_dump_now succeeded');
--
2.39.5 (Apple Git-154)
--w7OfHyILDI1ykikj--
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To: pgsql-general@postgresql.org
Cc: nathan@postgresql.org
Subject: Re: [PATCH 1/1] pg_prewarm privilege test
In-Reply-To: <no-message-id-49377@localhost>
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