AOF loading must not check ACL permissions in exec

src/acl.c

@@ -2094,6 +2094,9 @@ int ACLCheckAllUserCommandPerm(user *u, struct serverCommand *cmd, robj **argv,
 
 /* High level API for checking if a client can execute the queued up command */
 int ACLCheckAllPerm(client *c, int *idxptr) {
+    /* AOF replay is not subject to ACLs because the commands were allowed at the
+       time they were executed */
+    if (c->id == CLIENT_ID_AOF) return ACL_OK;
     int dbid = (c->flag.multi) ? c->mstate->transaction_db_id : c->db->id;
     return ACLCheckAllUserCommandPerm(c->user, c->cmd, c->argv, c->argc, dbid, idxptr);
 }

tests/integration/aof.tcl

@@ -376,6 +376,31 @@ tags {"aof external:skip logreqres:skip"} {
         }
     }
 
+    # A MULTI/EXEC block in the AOF must be replayed even when the default user
+    # is disabled. EXEC re-checks ACLs of the queued commands, but that check
+    # must not apply to the client used for loading the AOF, otherwise the
+    # transaction's writes are silently lost.
+    create_aof $aof_dirpath $aof_file {
+        append_to_aof [formatCommand set outside-tx 1]
+        append_to_aof [formatCommand multi]
+        append_to_aof [formatCommand set inside-tx-a 2]
+        append_to_aof [formatCommand set inside-tx-b 3]
+        append_to_aof [formatCommand exec]
+    }
+
+    set acl_config_lines {user {default off} user {someuser on nopass ~* &* +@all}}
+    start_server_aof_ex [list dir $server_path] [list wait_ready false config_lines $acl_config_lines] {
+        test {AOF with MULTI/EXEC is fully loaded when the default user is disabled} {
+            set c [valkey [srv host] [srv port] 0 $::tls]
+            $c auth someuser somepass
+            wait_done_loading $c
+            assert_equal 1 [$c get outside-tx]
+            assert_equal 2 [$c get inside-tx-a]
+            assert_equal 3 [$c get inside-tx-b]
+            $c close
+        }
+    }
+
     # The server could load AOF which has timestamp annotations inside
     create_aof $aof_dirpath $aof_file {
         append_to_aof "#TS:1628217470\r\n"