Check for CREATE privilege on the schema in CREATE STATISTICS.HEADmaster

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 <[email protected]>
Author: Jelte Fennema-Nio <[email protected]>
Co-authored-by: Nathan Bossart <[email protected]>
Reviewed-by: Noah Misch <[email protected]>
Reviewed-by: Álvaro Herrera <[email protected]>
Security: CVE-2025-12817
Backpatch-through: 13

6 files changed, 90 insertions, 4 deletions

diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 27bf67e7c4b..0cf0ea43f19 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -60,7 +60,7 @@ compare_int16(const void *a, const void *b)
  *		CREATE STATISTICS
  */
 ObjectAddress
-CreateStatistics(CreateStatsStmt *stmt)
+CreateStatistics(CreateStatsStmt *stmt, bool check_rights)
 {
 	int16		attnums[STATS_MAX_DIMENSIONS];
 	int			nattnums = 0;
@@ -171,6 +171,21 @@ CreateStatistics(CreateStatsStmt *stmt)
 	namestrcpy(&stxname, namestr);
 
 	/*
+	 * Check we have creation rights in target namespace.  Skip check if
+	 * caller doesn't want it.
+	 */
+	if (check_rights)
+	{
+		AclResult	aclresult;
+
+		aclresult = object_aclcheck(NamespaceRelationId, 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.
 	 */
 	if (SearchSysCacheExists2(STATEXTNAMENSP,
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 3aac459e483..23ebaa3f230 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -9682,7 +9682,7 @@ ATExecAddStatistics(AlteredTableInfo *tab, Relation rel,
 	/* The CreateStatsStmt has already been through transformStatsStmt */
 	Assert(stmt->transformed);
 
-	address = CreateStatistics(stmt);
+	address = CreateStatistics(stmt, !is_rebuild);
 
 	return address;
 }
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 082967c0a86..d18a3a60a46 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -1900,7 +1900,7 @@ ProcessUtilitySlow(ParseState *pstate,
 					/* Run parse analysis ... */
 					stmt = transformStatsStmt(relid, stmt, queryString);
 
-					address = CreateStatistics(stmt);
+					address = CreateStatistics(stmt, true);
 				}
 				break;
 
diff --git a/src/include/commands/defrem.h b/src/include/commands/defrem.h
index dd22b5efdfd..f3432b4b6a1 100644
--- a/src/include/commands/defrem.h
+++ b/src/include/commands/defrem.h
@@ -85,7 +85,7 @@ extern void RemoveOperatorById(Oid operOid);
 extern ObjectAddress AlterOperator(AlterOperatorStmt *stmt);
 
 /* commands/statscmds.c */
-extern ObjectAddress CreateStatistics(CreateStatsStmt *stmt);
+extern ObjectAddress CreateStatistics(CreateStatsStmt *stmt, bool check_rights);
 extern ObjectAddress AlterStatistics(AlterStatsStmt *stmt);
 extern void RemoveStatisticsById(Oid statsOid);
 extern void RemoveStatisticsDataById(Oid statsOid, bool inh);
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 73a7ef97355..495a1b35018 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -3451,6 +3451,41 @@ SELECT statistics_name, most_common_vals FROM pg_stats_ext_exprs x
  s_expr          | {1}
 (2 rows)
 
+-- CREATE STATISTICS checks for CREATE on the schema
+RESET SESSION AUTHORIZATION;
+CREATE SCHEMA sts_sch1 CREATE TABLE sts_sch1.tbl (a INT, b INT, c INT GENERATED ALWAYS AS (b * 2) STORED);
+CREATE SCHEMA sts_sch2;
+GRANT USAGE ON SCHEMA sts_sch1, sts_sch2 TO regress_stats_user1;
+ALTER TABLE sts_sch1.tbl OWNER TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS ON a, b, c FROM sts_sch1.tbl;
+ERROR:  permission denied for schema sts_sch1
+CREATE STATISTICS sts_sch2.fail ON a, b, c FROM sts_sch1.tbl;
+ERROR:  permission denied for schema sts_sch2
+RESET SESSION AUTHORIZATION;
+GRANT CREATE ON SCHEMA sts_sch1 TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS ON a, b, c FROM sts_sch1.tbl;
+CREATE STATISTICS sts_sch2.fail ON a, b, c FROM sts_sch1.tbl;
+ERROR:  permission denied for schema sts_sch2
+RESET SESSION AUTHORIZATION;
+REVOKE CREATE ON SCHEMA sts_sch1 FROM regress_stats_user1;
+GRANT CREATE ON SCHEMA sts_sch2 TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS ON a, b, c FROM sts_sch1.tbl;
+ERROR:  permission denied for schema sts_sch1
+CREATE STATISTICS sts_sch2.pass1 ON a, b, c FROM sts_sch1.tbl;
+RESET SESSION AUTHORIZATION;
+GRANT CREATE ON SCHEMA sts_sch1, sts_sch2 TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS ON a, b, c FROM sts_sch1.tbl;
+CREATE STATISTICS sts_sch2.pass2 ON a, b, c FROM sts_sch1.tbl;
+-- re-creating statistics via ALTER TABLE bypasses checks for CREATE on schema
+RESET SESSION AUTHORIZATION;
+REVOKE CREATE ON SCHEMA sts_sch1, sts_sch2 FROM regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+ALTER TABLE sts_sch1.tbl ALTER COLUMN a TYPE SMALLINT;
+ALTER TABLE sts_sch1.tbl ALTER COLUMN c SET EXPRESSION AS (a * 3);
 -- Tidy up
 DROP OPERATOR <<< (int, int);
 DROP FUNCTION op_leak(int, int);
@@ -3463,6 +3498,8 @@ 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, sts_sch2 CASCADE;
+NOTICE:  drop cascades to table sts_sch1.tbl
 DROP USER regress_stats_user1;
 CREATE TABLE grouping_unique (x integer);
 INSERT INTO grouping_unique (x) SELECT gs FROM generate_series(1,1000) AS gs;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 96771600d57..fc6f152a072 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -1759,6 +1759,39 @@ SELECT statistics_name, most_common_vals FROM pg_stats_ext x
 SELECT statistics_name, most_common_vals FROM pg_stats_ext_exprs x
     WHERE tablename = 'stats_ext_tbl' ORDER BY ROW(x.*);
 
+-- CREATE STATISTICS checks for CREATE on the schema
+RESET SESSION AUTHORIZATION;
+CREATE SCHEMA sts_sch1 CREATE TABLE sts_sch1.tbl (a INT, b INT, c INT GENERATED ALWAYS AS (b * 2) STORED);
+CREATE SCHEMA sts_sch2;
+GRANT USAGE ON SCHEMA sts_sch1, sts_sch2 TO regress_stats_user1;
+ALTER TABLE sts_sch1.tbl OWNER TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS ON a, b, c FROM sts_sch1.tbl;
+CREATE STATISTICS sts_sch2.fail ON a, b, c 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 ON a, b, c FROM sts_sch1.tbl;
+CREATE STATISTICS sts_sch2.fail ON a, b, c FROM sts_sch1.tbl;
+RESET SESSION AUTHORIZATION;
+REVOKE CREATE ON SCHEMA sts_sch1 FROM regress_stats_user1;
+GRANT CREATE ON SCHEMA sts_sch2 TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS ON a, b, c FROM sts_sch1.tbl;
+CREATE STATISTICS sts_sch2.pass1 ON a, b, c FROM sts_sch1.tbl;
+RESET SESSION AUTHORIZATION;
+GRANT CREATE ON SCHEMA sts_sch1, sts_sch2 TO regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+CREATE STATISTICS ON a, b, c FROM sts_sch1.tbl;
+CREATE STATISTICS sts_sch2.pass2 ON a, b, c FROM sts_sch1.tbl;
+
+-- re-creating statistics via ALTER TABLE bypasses checks for CREATE on schema
+RESET SESSION AUTHORIZATION;
+REVOKE CREATE ON SCHEMA sts_sch1, sts_sch2 FROM regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+ALTER TABLE sts_sch1.tbl ALTER COLUMN a TYPE SMALLINT;
+ALTER TABLE sts_sch1.tbl ALTER COLUMN c SET EXPRESSION AS (a * 3);
+
 -- Tidy up
 DROP OPERATOR <<< (int, int);
 DROP FUNCTION op_leak(int, int);
@@ -1767,6 +1800,7 @@ DROP FUNCTION op_leak(record, record);
 RESET SESSION AUTHORIZATION;
 DROP TABLE stats_ext_tbl;
 DROP SCHEMA tststats CASCADE;
+DROP SCHEMA sts_sch1, sts_sch2 CASCADE;
 DROP USER regress_stats_user1;
 
 CREATE TABLE grouping_unique (x integer);