Fix cache lookup hazards introduced by ff9618e82a.

ff9618e82a introduced has_partition_ancestor_privs(), which is used
to check whether a user has MAINTAIN on any partition ancestors.
This involves syscache lookups, and presently this function does
not take any relation locks, so it is likely subject to the same
kind of cache lookup failures that were fixed by 19de0ab23c.

To fix this problem, this commit partially reverts ff9618e82a.
Specifically, it removes the partition-related changes, including
the has_partition_ancestor_privs() function mentioned above.  This
means that MAINTAIN on a partitioned table is no longer sufficient
to perform maintenance commands on its partitions.  This is more
like how privileges for maintenance commands work on supported
versions.  Privileges are checked for each partition, so a command
that flows down to all partitions might refuse to process them
(e.g., if the current user doesn't have MAINTAIN on the partition).

In passing, adjust a few related comments and error messages, and
add a test for the privilege checks for CLUSTER on a partitioned
table.

Reviewed-by: Michael Paquier, Jeff Davis
Discussion: https://postgr.es/m/20230613211246.GA219055%40nathanxps13

1 files changed, 4 insertions, 30 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 4d49d70c339..9b12bc44d73 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -16986,6 +16986,7 @@ RangeVarCallbackMaintainsTable(const RangeVar *relation,
 							   Oid relId, Oid oldRelId, void *arg)
 {
 	char		relkind;
+	AclResult	aclresult;
 
 	/* Nothing to do if the relation was not found. */
 	if (!OidIsValid(relId))
@@ -17006,36 +17007,9 @@ RangeVarCallbackMaintainsTable(const RangeVar *relation,
 				 errmsg("\"%s\" is not a table or materialized view", relation->relname)));
 
 	/* Check permissions */
-	if (pg_class_aclcheck(relId, GetUserId(), ACL_MAINTAIN) != ACLCHECK_OK &&
-		!has_partition_ancestor_privs(relId, GetUserId(), ACL_MAINTAIN))
-		aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_TABLE,
-					   relation->relname);
-}
-
-/*
- * If relid is a partition, returns whether userid has any of the privileges
- * specified in acl on any of its ancestors.  Otherwise, returns false.
- */
-bool
-has_partition_ancestor_privs(Oid relid, Oid userid, AclMode acl)
-{
-	List	   *ancestors;
-	ListCell   *lc;
-
-	if (!get_rel_relispartition(relid))
-		return false;
-
-	ancestors = get_partition_ancestors(relid);
-	foreach(lc, ancestors)
-	{
-		Oid			ancestor = lfirst_oid(lc);
-
-		if (OidIsValid(ancestor) &&
-			pg_class_aclcheck(ancestor, userid, acl) == ACLCHECK_OK)
-			return true;
-	}
-
-	return false;
+	aclresult = pg_class_aclcheck(relId, GetUserId(), ACL_MAINTAIN);
+	if (aclresult != ACLCHECK_OK)
+		aclcheck_error(aclresult, OBJECT_TABLE, relation->relname);
 }
 
 /*