In REFRESH MATERIALIZED VIEW, set user ID before running user code.

nmisch · nmisch · commit 677a49478906 · 2022-05-09T08:35:12.000-07:00
It intended to, but did not, achieve this. Adopt the new standard of setting user ID just after locking the relation. Back-patch to v10 (all supported versions). Reviewed by Simon Riggs. Reported by Alvaro Herrera. Security: CVE-2022-1552
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
@@ -167,6 +167,17 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 										  lockmode, 0,
 										  RangeVarCallbackOwnsTable, NULL);
 	matviewRel = table_open(matviewOid, NoLock);
+	relowner = matviewRel->rd_rel->relowner;
+
+	/*
+	 * Switch to the owner's userid, so that any functions are run as that
+	 * user.  Also lock down security-restricted operations and arrange to
+	 * make GUC variable changes local to this command.
+	 */
+	GetUserIdAndSecContext(&save_userid, &save_sec_context);
+	SetUserIdAndSecContext(relowner,
+						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
+	save_nestlevel = NewGUCNestLevel();
 
 	/* Make sure it is a materialized view. */
 	if (matviewRel->rd_rel->relkind != RELKIND_MATVIEW)
@@ -269,19 +280,6 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 	 */
 	SetMatViewPopulatedState(matviewRel, !stmt->skipData);
 
-	relowner = matviewRel->rd_rel->relowner;
-
-	/*
-	 * Switch to the owner's userid, so that any functions are run as that
-	 * user.  Also arrange to make GUC variable changes local to this command.
-	 * Don't lock it down too tight to create a temporary table just yet.  We
-	 * will switch modes when we are about to execute user code.
-	 */
-	GetUserIdAndSecContext(&save_userid, &save_sec_context);
-	SetUserIdAndSecContext(relowner,
-						   save_sec_context | SECURITY_LOCAL_USERID_CHANGE);
-	save_nestlevel = NewGUCNestLevel();
-
 	/* Concurrent refresh builds new data in temp tablespace, and does diff. */
 	if (concurrent)
 	{
@@ -304,12 +302,6 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 	LockRelationOid(OIDNewHeap, AccessExclusiveLock);
 	dest = CreateTransientRelDestReceiver(OIDNewHeap);
 
-	/*
-	 * Now lock down security-restricted operations.
-	 */
-	SetUserIdAndSecContext(relowner,
-						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
-
 	/* Generate the data, if wanted. */
 	if (!stmt->skipData)
 		processed = refresh_matview_datafill(dest, dataQuery, queryString);
diff --git a/src/test/regress/expected/privileges.out b/src/test/regress/expected/privileges.out
@@ -1564,6 +1564,22 @@ CONTEXT:  SQL function "unwanted_grant" statement 1
 SQL statement "SELECT unwanted_grant()"
 PL/pgSQL function sro_trojan() line 1 at PERFORM
 SQL function "mv_action" statement 1
+-- REFRESH MATERIALIZED VIEW CONCURRENTLY use of eval_const_expressions()
+SET SESSION AUTHORIZATION regress_sro_user;
+CREATE FUNCTION unwanted_grant_nofail(int) RETURNS int
+	IMMUTABLE LANGUAGE plpgsql AS $$
+BEGIN
+	PERFORM unwanted_grant();
+	RAISE WARNING 'owned';
+	RETURN 1;
+EXCEPTION WHEN OTHERS THEN
+	RETURN 2;
+END$$;
+CREATE MATERIALIZED VIEW sro_index_mv AS SELECT 1 AS c;
+CREATE UNIQUE INDEX ON sro_index_mv (c) WHERE unwanted_grant_nofail(1) > 0;
+\c -
+REFRESH MATERIALIZED VIEW CONCURRENTLY sro_index_mv;
+REFRESH MATERIALIZED VIEW sro_index_mv;
 DROP OWNED BY regress_sro_user;
 DROP ROLE regress_sro_user;
 -- Admin options
diff --git a/src/test/regress/sql/privileges.sql b/src/test/regress/sql/privileges.sql
@@ -979,6 +979,23 @@ REFRESH MATERIALIZED VIEW sro_mv;
 REFRESH MATERIALIZED VIEW sro_mv;
 BEGIN; SET CONSTRAINTS ALL IMMEDIATE; REFRESH MATERIALIZED VIEW sro_mv; COMMIT;
 
+-- REFRESH MATERIALIZED VIEW CONCURRENTLY use of eval_const_expressions()
+SET SESSION AUTHORIZATION regress_sro_user;
+CREATE FUNCTION unwanted_grant_nofail(int) RETURNS int
+	IMMUTABLE LANGUAGE plpgsql AS $$
+BEGIN
+	PERFORM unwanted_grant();
+	RAISE WARNING 'owned';
+	RETURN 1;
+EXCEPTION WHEN OTHERS THEN
+	RETURN 2;
+END$$;
+CREATE MATERIALIZED VIEW sro_index_mv AS SELECT 1 AS c;
+CREATE UNIQUE INDEX ON sro_index_mv (c) WHERE unwanted_grant_nofail(1) > 0;
+\c -
+REFRESH MATERIALIZED VIEW CONCURRENTLY sro_index_mv;
+REFRESH MATERIALIZED VIEW sro_index_mv;
+
 DROP OWNED BY regress_sro_user;
 DROP ROLE regress_sro_user;
 
