ensure that only valid group members are returned

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>

Author: blizzz

apps/user_ldap/lib/Group_LDAP.php

@@ -812,6 +812,7 @@ private function getGroupsByMember($dn, &$seen = null) {
 	 * @param int $limit
 	 * @param int $offset
 	 * @return array with user ids
+	 * @throws \Exception
 	 */
 	public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
 		if(!$this->enabled) {
@@ -872,17 +873,29 @@ public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
 				$groupUsers[] = $this->access->dn2username($ldap_users[0]['dn'][0]);
 			} else {
 				//we got DNs, check if we need to filter by search or we can give back all of them
-				if ($search !== '') {
-					if(!$this->access->readAttribute($member,
+				$uid = $this->access->dn2username($member);
+				if(!$uid) {
+					continue;
+				}
+
+				$cacheKey = 'userExistsOnLDAP' . $uid;
+				$userExists = $this->access->connection->getFromCache($cacheKey);
+				if($userExists === false) {
+					continue;
+				}
+				if($userExists === null || $search !== '') {
+					if (!$this->access->readAttribute($member,
 						$this->access->connection->ldapUserDisplayName,
-						$this->access->getFilterPartForUserSearch($search))) {
+						$this->access->getFilterPartForUserSearch($search)))
+					{
+						if($search === '') {
+							$this->access->connection->writeToCache($cacheKey, false);
+						}
 						continue;
 					}
+					$this->access->connection->writeToCache($cacheKey, true);
 				}
-				// dn2username will also check if the users belong to the allowed base
-				if($ocname = $this->access->dn2username($member)) {
-					$groupUsers[] = $ocname;
-				}
+				$groupUsers[] = $uid;
 			}
 		}