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[PATCH 3/5] Move conversion of a "historic" to MVCC snapshot to a separate function.
331+ messages / 3 participants
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* [PATCH 3/5] Move conversion of a "historic" to MVCC snapshot to a separate function.
@ 2026-02-16 19:49  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 331+ messages in thread

From: Antonin Houska @ 2026-02-16 19:49 UTC (permalink / raw)

The conversion is now handled by SnapBuildMVCCFromHistoric(). REPACK
CONCURRENTLY will also need it.
---
 src/backend/replication/logical/snapbuild.c | 59 +++++++++++++++++----
 src/backend/utils/time/snapmgr.c            |  3 +-
 src/include/replication/snapbuild.h         |  1 +
 src/include/utils/snapmgr.h                 |  1 +
 4 files changed, 52 insertions(+), 12 deletions(-)

diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 7f79621b57e..a738ad8a864 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -440,10 +440,7 @@ Snapshot
 SnapBuildInitialSnapshot(SnapBuild *builder)
 {
 	Snapshot	snap;
-	TransactionId xid;
 	TransactionId safeXid;
-	TransactionId *newxip;
-	int			newxcnt = 0;
 
 	Assert(XactIsoLevel == XACT_REPEATABLE_READ);
 	Assert(builder->building_full_snapshot);
@@ -485,7 +482,35 @@ SnapBuildInitialSnapshot(SnapBuild *builder)
 
 	MyProc->xmin = snap->xmin;
 
-	/* allocate in transaction context */
+	/* Convert the historic snapshot to MVCC snapshot. */
+	return SnapBuildMVCCFromHistoric(snap, true);
+}
+
+/*
+ * Turn a historic MVCC snapshot into an ordinary MVCC snapshot.
+ *
+ * Unlike a regular (non-historic) MVCC snapshot, the 'xip' array of this
+ * snapshot contains not only running main transactions, but also their
+ * subtransactions. On the other hand, 'subxip' will usually be empty. This
+ * difference does not affect the result of XidInMVCCSnapshot() because it
+ * searches both in 'xip' and 'subxip'.
+ *
+ * Pass true for 'in_place' if you don't care about modifying the source
+ * snapshot. If you need a new instance, and one that was allocated as a
+ * single chunk of memory, pass false.
+ */
+Snapshot
+SnapBuildMVCCFromHistoric(Snapshot snapshot, bool in_place)
+{
+	TransactionId xid;
+	TransactionId *oldxip = snapshot->xip;
+	uint32		oldxcnt = snapshot->xcnt;
+	TransactionId *newxip;
+	int			newxcnt = 0;
+	Snapshot	result;
+
+	Assert(snapshot->snapshot_type == SNAPSHOT_HISTORIC_MVCC);
+
 	newxip = palloc_array(TransactionId, GetMaxSnapshotXidCount());
 
 	/*
@@ -494,7 +519,7 @@ SnapBuildInitialSnapshot(SnapBuild *builder)
 	 * classical snapshot by marking all non-committed transactions as
 	 * in-progress. This can be expensive.
 	 */
-	for (xid = snap->xmin; NormalTransactionIdPrecedes(xid, snap->xmax);)
+	for (xid = snapshot->xmin; NormalTransactionIdPrecedes(xid, snapshot->xmax);)
 	{
 		void	   *test;
 
@@ -502,7 +527,7 @@ SnapBuildInitialSnapshot(SnapBuild *builder)
 		 * Check whether transaction committed using the decoding snapshot
 		 * meaning of ->xip.
 		 */
-		test = bsearch(&xid, snap->xip, snap->xcnt,
+		test = bsearch(&xid, snapshot->xip, snapshot->xcnt,
 					   sizeof(TransactionId), xidComparator);
 
 		if (test == NULL)
@@ -519,11 +544,25 @@ SnapBuildInitialSnapshot(SnapBuild *builder)
 	}
 
 	/* adjust remaining snapshot fields as needed */
-	snap->snapshot_type = SNAPSHOT_MVCC;
-	snap->xcnt = newxcnt;
-	snap->xip = newxip;
+	snapshot->xcnt = newxcnt;
+	snapshot->xip = newxip;
+
+	if (in_place)
+		result = snapshot;
+	else
+	{
+		result = CopySnapshot(snapshot);
+
+		/* Restore the original values so the source is intact. */
+		snapshot->xip = oldxip;
+		snapshot->xcnt = oldxcnt;
+
+		/* newxip has been copied */
+		pfree(newxip);
+	}
+	result->snapshot_type = SNAPSHOT_MVCC;
 
-	return snap;
+	return result;
 }
 
 /*
diff --git a/src/backend/utils/time/snapmgr.c b/src/backend/utils/time/snapmgr.c
index 2e6197f5f35..3af1b366adf 100644
--- a/src/backend/utils/time/snapmgr.c
+++ b/src/backend/utils/time/snapmgr.c
@@ -213,7 +213,6 @@ typedef struct ExportedSnapshot
 static List *exportedSnapshots = NIL;
 
 /* Prototypes for local functions */
-static Snapshot CopySnapshot(Snapshot snapshot);
 static void UnregisterSnapshotNoOwner(Snapshot snapshot);
 static void FreeSnapshot(Snapshot snapshot);
 static void SnapshotResetXmin(void);
@@ -604,7 +603,7 @@ SetTransactionSnapshot(Snapshot sourcesnap, VirtualTransactionId *sourcevxid,
  * The copy is palloc'd in TopTransactionContext and has initial refcounts set
  * to 0.  The returned snapshot has the copied flag set.
  */
-static Snapshot
+Snapshot
 CopySnapshot(Snapshot snapshot)
 {
 	Snapshot	newsnap;
diff --git a/src/include/replication/snapbuild.h b/src/include/replication/snapbuild.h
index ccded021433..34383dea776 100644
--- a/src/include/replication/snapbuild.h
+++ b/src/include/replication/snapbuild.h
@@ -73,6 +73,7 @@ extern void FreeSnapshotBuilder(SnapBuild *builder);
 extern void SnapBuildSnapDecRefcount(Snapshot snap);
 
 extern Snapshot SnapBuildInitialSnapshot(SnapBuild *builder);
+extern Snapshot SnapBuildMVCCFromHistoric(Snapshot snapshot, bool in_place);
 extern const char *SnapBuildExportSnapshot(SnapBuild *builder);
 extern void SnapBuildClearExportedSnapshot(void);
 extern void SnapBuildResetExportedSnapshotState(void);
diff --git a/src/include/utils/snapmgr.h b/src/include/utils/snapmgr.h
index b8c01a291a1..de824945f0b 100644
--- a/src/include/utils/snapmgr.h
+++ b/src/include/utils/snapmgr.h
@@ -63,6 +63,7 @@ extern Snapshot GetTransactionSnapshot(void);
 extern Snapshot GetLatestSnapshot(void);
 extern void SnapshotSetCommandId(CommandId curcid);
 
+extern Snapshot CopySnapshot(Snapshot snapshot);
 extern Snapshot GetCatalogSnapshot(Oid relid);
 extern Snapshot GetNonHistoricCatalogSnapshot(Oid relid);
 extern void InvalidateCatalogSnapshot(void);
-- 
2.47.3


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v34-0004-Add-CONCURRENTLY-option-to-REPACK-command.patch



^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread

* [PATCH] Limit PL/Perl scalar copies to work_mem
@ 2026-07-06 22:13  Andrey Rachitskiy <pl0h0yp1@gmail.com>
  0 siblings, 0 replies; 331+ messages in thread

From: Andrey Rachitskiy @ 2026-07-06 22:13 UTC (permalink / raw)

When a PL/Perl function returns a very large text value, sv2cstr() copies
the entire Perl string into backend memory with no size check.  A user
with permission to create untrusted PL/Perl functions can return strings
far larger than work_mem and risk getting the backend killed by the OOM
killer.

Reject Perl strings larger than work_mem * 1024 bytes, capped by
MaxAllocSize, before copying them through sv2cstr().  This follows the
same work_mem-based limit pattern used elsewhere in the backend.

Add a plperl regression test that attempts to return a 16MB string with
the default 4MB work_mem setting.

Author: Andrey Rachitskiy <pl0h0yp1@gmail.com>
---
 src/pl/plperl/expected/plperl.out |  8 +++++++
 src/pl/plperl/plperl.h            | 34 ++++++++++++++++++++++++++++++
 src/pl/plperl/sql/plperl.sql      |  7 ++++++
 3 files changed, 49 insertions(+)
diff --git a/src/pl/plperl/expected/plperl.out b/src/pl/plperl/expected/plperl.out
index e3d7c88..50c788b 100644
--- a/src/pl/plperl/expected/plperl.out
+++ b/src/pl/plperl/expected/plperl.out
@@ -792,3 +792,11 @@ SELECT self_modify(42);
          126
 (1 row)
 
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+SELECT perl_oversized_text();
+ERROR:  Perl value exceeds maximum allowed size (4194304 bytes)
+HINT:  Increase work_mem or reduce the result size.
+CONTEXT:  PL/Perl function "perl_oversized_text"
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
index 4c03f9e..1ccce6d 100644
--- a/src/pl/plperl/plperl.h
+++ b/src/pl/plperl/plperl.h
@@ -17,6 +17,8 @@
 
 /* defines free() by way of system headers, so must be included before perl.h */
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
+#include "utils/memutils.h"
 
 /*
  * Pull in Perl headers via a wrapper header, to control the scope of
@@ -40,6 +42,36 @@ char	   *plperl_sv_to_literal(SV *, char *);
 void		plperl_util_elog(int level, SV *msg);
 
 
+/*
+ * Maximum byte size for a Perl scalar copied through sv2cstr().
+ *
+ * This follows the same work_mem * 1024 pattern used elsewhere in the
+ * backend (e.g. reorderbuffer.c, nodeHash.c) and is capped by MaxAllocSize.
+ */
+static inline Size
+plperl_max_scalar_bytes(void)
+{
+	Size		limit = (Size) work_mem * (Size) 1024;
+
+	return Min(limit, MaxAllocSize - 1);
+}
+
+/*
+ * Reject Perl strings that are too large to copy into backend memory.
+ */
+static inline void
+plperl_check_sv_length(STRLEN len)
+{
+	Size		max_len = plperl_max_scalar_bytes();
+
+	if ((Size) len > max_len)
+		erereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("Perl value exceeds maximum allowed size (%zu bytes)",
+						max_len),
+			 errhint("Increase work_mem or reduce the result size.")));
+}
+
 /* helper functions */
 
 /*
@@ -127,6 +159,8 @@ sv2cstr(SV *sv)
 	else
 		val = SvPVutf8(sv, len);
 
+	plperl_check_sv_length(len);
+
 	/*
 	 * Now convert to database encoding.  We use perl's length in the event we
 	 * had an embedded null byte to ensure we error out properly.
diff --git a/src/pl/plperl/sql/plperl.sql b/src/pl/plperl/sql/plperl.sql
index bb0b8ce..0470a2b 100644
--- a/src/pl/plperl/sql/plperl.sql
+++ b/src/pl/plperl/sql/plperl.sql
@@ -521,3 +521,10 @@ $$ LANGUAGE plperl;
 
 SELECT self_modify(42);
 SELECT self_modify(42);
+
+-- oversized text results are rejected at the PL boundary
+CREATE OR REPLACE FUNCTION perl_oversized_text() RETURNS text AS $$
+	return 'x' x (16 * 1024 * 1024);
+$$ LANGUAGE plperl;
+
+SELECT perl_oversized_text();

--MP_/sDTAhto+gkG/PMs8Alw6m8e--





^ permalink  raw  reply  [nested|flat] 331+ messages in thread