Revert commit 56bc82a.

MasaoFujii · MasaoFujii · commit d034ab0bb2ae · 2020-02-03T12:45:01.000+09:00
This commit reverts the fix "Make inherited TRUNCATE perform access permission checks on parent table only" only in the back branches. It's not hard to imagine that there are some applications expecting the old behavior and the fix breaks their security. To avoid this compatibility problem, we decided to apply the fix only in HEAD and revert it in all supported back branches. Discussion: https://postgr.es/m/21015.1580400165@sss.pgh.pa.us
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
@@ -262,9 +262,7 @@ struct DropRelationCallbackState
 #define		ATT_COMPOSITE_TYPE		0x0010
 #define		ATT_FOREIGN_TABLE		0x0020
 
-static void truncate_check_rel(Oid relid, Form_pg_class reltuple);
-static void truncate_check_perms(Oid relid, Form_pg_class reltuple);
-static void truncate_check_activity(Relation rel);
+static void truncate_check_rel(Relation rel);
 static List *MergeAttributes(List *schema, List *supers, char relpersistence,
 				List **supOids, List **supconstr, int *supOidCount);
 static bool MergeCheckConstraint(List *constraints, char *name, Node *expr);
@@ -1020,11 +1018,7 @@ ExecuteTruncate(TruncateStmt *stmt)
 			heap_close(rel, lockmode);
 			continue;
 		}
-
-		truncate_check_rel(myrelid, rel->rd_rel);
-		truncate_check_perms(myrelid, rel->rd_rel);
-		truncate_check_activity(rel);
-
+		truncate_check_rel(rel);
 		rels = lappend(rels, rel);
 		relids = lappend_oid(relids, myrelid);
 
@@ -1060,15 +1054,7 @@ ExecuteTruncate(TruncateStmt *stmt)
 					continue;
 				}
 
-				/*
-				 * Inherited TRUNCATE commands perform access
-				 * permission checks on the parent table only.
-				 * So we skip checking the children's permissions
-				 * and don't call truncate_check_perms() here.
-				 */
-				truncate_check_rel(RelationGetRelid(rel), rel->rd_rel);
-				truncate_check_activity(rel);
-
+				truncate_check_rel(rel);
 				rels = lappend(rels, rel);
 				relids = lappend_oid(relids, childrelid);
 			}
@@ -1102,9 +1088,7 @@ ExecuteTruncate(TruncateStmt *stmt)
 				ereport(NOTICE,
 						(errmsg("truncate cascades to table \"%s\"",
 								RelationGetRelationName(rel))));
-				truncate_check_rel(relid, rel->rd_rel);
-				truncate_check_perms(relid, rel->rd_rel);
-				truncate_check_activity(rel);
+				truncate_check_rel(rel);
 				rels = lappend(rels, rel);
 				relids = lappend_oid(relids, relid);
 			}
@@ -1305,45 +1289,30 @@ ExecuteTruncate(TruncateStmt *stmt)
  * Check that a given rel is safe to truncate.  Subroutine for ExecuteTruncate
  */
 static void
-truncate_check_rel(Oid relid, Form_pg_class reltuple)
+truncate_check_rel(Relation rel)
 {
-	char	   *relname = NameStr(reltuple->relname);
+	AclResult	aclresult;
 
 	/* Only allow truncate on regular tables */
-	if (reltuple->relkind != RELKIND_RELATION)
+	if (rel->rd_rel->relkind != RELKIND_RELATION)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a table", relname)));
+				 errmsg("\"%s\" is not a table",
+						RelationGetRelationName(rel))));
 
-	if (!allowSystemTableMods && IsSystemClass(relid, reltuple))
+	/* Permissions checks */
+	aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
+								  ACL_TRUNCATE);
+	if (aclresult != ACLCHECK_OK)
+		aclcheck_error(aclresult, ACL_KIND_CLASS,
+					   RelationGetRelationName(rel));
+
+	if (!allowSystemTableMods && IsSystemRelation(rel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 errmsg("permission denied: \"%s\" is a system catalog",
-						relname)));
-}
-
-/*
- * Check that current user has the permission to truncate given relation.
- */
-static void
-truncate_check_perms(Oid relid, Form_pg_class reltuple)
-{
-	char	   *relname = NameStr(reltuple->relname);
-	AclResult	aclresult;
-
-	/* Permissions checks */
-	aclresult = pg_class_aclcheck(relid, GetUserId(), ACL_TRUNCATE);
-	if (aclresult != ACLCHECK_OK)
-		aclcheck_error(aclresult, ACL_KIND_CLASS, relname);
-}
+						RelationGetRelationName(rel))));
 
-/*
- * Set of extra sanity checks to check if a given relation is safe to
- * truncate.
- */
-static void
-truncate_check_activity(Relation rel)
-{
 	/*
 	 * Don't allow truncate on temp tables of other backends ... their local
 	 * buffer manager is not going to cope.
diff --git a/src/test/regress/expected/privileges.out b/src/test/regress/expected/privileges.out
@@ -656,27 +656,6 @@ SELECT oid FROM atestp2; -- ok
 -----
 (0 rows)
 
--- child's permissions do not apply when operating on parent
-SET SESSION AUTHORIZATION regressuser1;
-REVOKE ALL ON atestc FROM regressuser2;
-GRANT ALL ON atestp1 TO regressuser2;
-SET SESSION AUTHORIZATION regressuser2;
-SELECT f2 FROM atestp1; -- ok
- f2 
-----
-(0 rows)
-
-SELECT f2 FROM atestc; -- fail
-ERROR:  permission denied for relation atestc
-DELETE FROM atestp1; -- ok
-DELETE FROM atestc; -- fail
-ERROR:  permission denied for relation atestc
-UPDATE atestp1 SET f1 = 1; -- ok
-UPDATE atestc SET f1 = 1; -- fail
-ERROR:  permission denied for relation atestc
-TRUNCATE atestp1; -- ok
-TRUNCATE atestc; -- fail
-ERROR:  permission denied for relation atestc
 -- privileges on functions, languages
 -- switch to superuser
 \c -
diff --git a/src/test/regress/sql/privileges.sql b/src/test/regress/sql/privileges.sql
@@ -414,20 +414,6 @@ SELECT fy FROM atestp2; -- ok
 SELECT atestp2 FROM atestp2; -- ok
 SELECT oid FROM atestp2; -- ok
 
--- child's permissions do not apply when operating on parent
-SET SESSION AUTHORIZATION regressuser1;
-REVOKE ALL ON atestc FROM regressuser2;
-GRANT ALL ON atestp1 TO regressuser2;
-SET SESSION AUTHORIZATION regressuser2;
-SELECT f2 FROM atestp1; -- ok
-SELECT f2 FROM atestc; -- fail
-DELETE FROM atestp1; -- ok
-DELETE FROM atestc; -- fail
-UPDATE atestp1 SET f1 = 1; -- ok
-UPDATE atestc SET f1 = 1; -- fail
-TRUNCATE atestp1; -- ok
-TRUNCATE atestc; -- fail
-
 -- privileges on functions, languages
 
 -- switch to superuser
