userdb: return ESRCH if userdb service refuses a user/group name as i…

…nvalid

if a userdb service refuse a user/group name as invalid, let's turn this
into ESRCH client-side following that there definitely is no user/group
record for a completely invalid user/group name.

Replaces: #34558
(cherry picked from commit 69cc4ee134f420dcdd6aac08446bd852d8739694)

Resolves: RHEL-55266

src/shared/userdb.c

@@ -159,9 +159,15 @@ static int userdb_on_query_reply(
         if (error_id) {
                 log_debug("Got lookup error: %s", error_id);
 
+                /* Convert various forms of record not found into -ESRCH, since NSS typically doesn't care,
+                 * about the details. Note that if a userName specification is refused as invalid parameter,
+                 * we also turn this into -ESRCH following the logic that there cannot be a user record for a
+                 * completely invalid user name. */
                 if (STR_IN_SET(error_id,
                                "io.systemd.UserDatabase.NoRecordFound",
-                               "io.systemd.UserDatabase.ConflictingRecordFound"))
+                               "io.systemd.UserDatabase.ConflictingRecordFound") ||
+                    varlink_error_is_invalid_parameter(error_id, parameters, "userName") ||
+                    varlink_error_is_invalid_parameter(error_id, parameters, "groupName"))
                         r = -ESRCH;
                 else if (streq(error_id, "io.systemd.UserDatabase.ServiceNotAvailable"))
                         r = -EHOSTDOWN;