Check for CREATE privilege on the schema in CREATE STATISTICS.

This omission allowed table owners to create statistics in any
schema, potentially leading to unexpected naming conflicts.  For
ALTER TABLE commands that require re-creating statistics objects,
skip this check in case the user has since lost CREATE on the
schema.  The addition of a second parameter to CreateStatistics()
breaks ABI compatibility, but we are unaware of any impacted
third-party code.

Reported-by: Jelte Fennema-Nio <postgres@jeltef.nl>
Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Co-authored-by: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Noah Misch <noah@leadboat.com>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Security: CVE-2025-12817
Backpatch-through: 13

3 files changed, 35 insertions, 0 deletions

diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index f3a6c2e7cc0..b524a08ec7e 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -33,6 +33,7 @@
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/inval.h"
+#include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
@@ -89,6 +90,7 @@ CreateStatistics(CreateStatsStmt *stmt)
 	bool		requested_type = false;
 	int			i;
 	ListCell   *cell;
+	AclResult	aclresult;
 
 	Assert(IsA(stmt, CreateStatsStmt));
 
@@ -167,6 +169,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 	}
 	namestrcpy(&stxname, namestr);
 
+	/* Check we have creation rights in target namespace. */
+	aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(), ACL_CREATE);
+	if (aclresult != ACLCHECK_OK)
+		aclcheck_error(aclresult, OBJECT_SCHEMA,
+					   get_namespace_name(namespaceId));
+
 	/*
 	 * Deal with the possibility that the statistics object already exists.
 	 */
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index fa06298504e..b5b3e5dc81c 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1745,6 +1745,18 @@ SELECT * FROM tststats.priv_test_parent_tbl t
 (0 rows)
 
 DELETE FROM tststats.priv_test_parent_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak
+-- CREATE STATISTICS checks for CREATE on the schema
+RESET SESSION AUTHORIZATION;
+CREATE SCHEMA sts_sch1 CREATE TABLE sts_sch1.tbl (a INT, b INT);
+GRANT USAGE ON SCHEMA sts_sch1 TO regress_stats_user1;
+ALTER TABLE sts_sch1.tbl OWNER TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS sts_sch1.fail ON a, b FROM sts_sch1.tbl;
+ERROR:  permission denied for schema sts_sch1
+RESET SESSION AUTHORIZATION;
+GRANT CREATE ON SCHEMA sts_sch1 TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS sts_sch1.pass ON a, b FROM sts_sch1.tbl;
 -- Tidy up
 DROP OPERATOR <<< (int, int);
 DROP FUNCTION op_leak(int, int);
@@ -1756,4 +1768,6 @@ NOTICE:  drop cascades to 3 other objects
 DETAIL:  drop cascades to table tststats.priv_test_parent_tbl
 drop cascades to table tststats.priv_test_tbl
 drop cascades to view tststats.priv_test_view
+DROP SCHEMA sts_sch1 CASCADE;
+NOTICE:  drop cascades to table sts_sch1.tbl
 DROP USER regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index dd632f894e5..72e6489bbb7 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -963,6 +963,18 @@ SELECT * FROM tststats.priv_test_parent_tbl t
  WHERE a <<< 0 AND (b <<< 0 OR t.* <<< (1, 1) IS NOT NULL); -- Should not leak
 DELETE FROM tststats.priv_test_parent_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak
 
+-- CREATE STATISTICS checks for CREATE on the schema
+RESET SESSION AUTHORIZATION;
+CREATE SCHEMA sts_sch1 CREATE TABLE sts_sch1.tbl (a INT, b INT);
+GRANT USAGE ON SCHEMA sts_sch1 TO regress_stats_user1;
+ALTER TABLE sts_sch1.tbl OWNER TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS sts_sch1.fail ON a, b FROM sts_sch1.tbl;
+RESET SESSION AUTHORIZATION;
+GRANT CREATE ON SCHEMA sts_sch1 TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS sts_sch1.pass ON a, b FROM sts_sch1.tbl;
+
 -- Tidy up
 DROP OPERATOR <<< (int, int);
 DROP FUNCTION op_leak(int, int);
@@ -970,4 +982,5 @@ DROP OPERATOR <<< (record, record);
 DROP FUNCTION op_leak(record, record);
 RESET SESSION AUTHORIZATION;
 DROP SCHEMA tststats CASCADE;
+DROP SCHEMA sts_sch1 CASCADE;
 DROP USER regress_stats_user1;