Fix LDAP race conditions

* getFromCache is wrapped in isCached
* inbetween the two calls the cache entry hits it's TTL
* getFromCache returns null
* this fix only checkes if the returned value is null and
  return only non-null values

3 files changed, 9 insertions, 25 deletions

diff --git a/apps/user_ldap/lib/access.php b/apps/user_ldap/lib/access.php
index 135eca1e625..569d2dbcbe9 100644
--- a/apps/user_ldap/lib/access.php
+++ b/apps/user_ldap/lib/access.php
@@ -364,8 +364,9 @@ class Access extends LDAPUtility implements user\IUserTools {
 		$validGroupDNs = [];
 		foreach($groupDNs as $dn) {
 			$cacheKey = 'groupsMatchFilter-'.$dn;
-			if($this->connection->isCached($cacheKey)) {
-				if($this->connection->getFromCache($cacheKey)) {
+			$groupMatchFilter = $this->connection->getFromCache($cacheKey);
+			if(!is_null($groupMatchFilter)) {
+				if($groupMatchFilter) {
 					$validGroupDNs[] = $dn;
 				}
 				continue;
@@ -1505,8 +1506,9 @@ class Access extends LDAPUtility implements user\IUserTools {
 	public function getSID($dn) {
 		$domainDN = $this->getDomainDNFromDN($dn);
 		$cacheKey = 'getSID-'.$domainDN;
-		if($this->connection->isCached($cacheKey)) {
-			return $this->connection->getFromCache($cacheKey);
+		$sid = $this->connection->getFromCache($cacheKey);
+		if(!is_null($sid)) {
+			return $sid;
 		}
 
 		$objectSid = $this->readAttribute($domainDN, 'objectsid');
diff --git a/apps/user_ldap/lib/connection.php b/apps/user_ldap/lib/connection.php
index 53c9b3790a7..974cad6dc02 100644
--- a/apps/user_ldap/lib/connection.php
+++ b/apps/user_ldap/lib/connection.php
@@ -213,10 +213,6 @@ class Connection extends LDAPUtility {
 		if(is_null($this->cache) || !$this->configuration->ldapCacheTTL) {
 			return null;
 		}
-		if(!$this->isCached($key)) {
-			return null;
-
-		}
 		$key = $this->getCacheKey($key);
 
 		return json_decode(base64_decode($this->cache->get($key)), true);
@@ -224,21 +220,6 @@ class Connection extends LDAPUtility {
 
 	/**
 	 * @param string $key
-	 * @return bool
-	 */
-	public function isCached($key) {
-		if(!$this->configured) {
-			$this->readConfiguration();
-		}
-		if(is_null($this->cache) || !$this->configuration->ldapCacheTTL) {
-			return false;
-		}
-		$key = $this->getCacheKey($key);
-		return $this->cache->hasKey($key);
-	}
-
-	/**
-	 * @param string $key
 	 * @param mixed $value
 	 *
 	 * @return string
diff --git a/apps/user_ldap/lib/user/user.php b/apps/user_ldap/lib/user/user.php
index 23aba0e0d85..4da8ae5f098 100644
--- a/apps/user_ldap/lib/user/user.php
+++ b/apps/user_ldap/lib/user/user.php
@@ -297,8 +297,9 @@ class User {
 
 	public function getMemberOfGroups() {
 		$cacheKey = 'getMemberOf'.$this->getUsername();
-		if($this->connection->isCached($cacheKey)) {
-			return $this->connection->getFromCache($cacheKey);
+		$memberOfGroups = $this->connection->getFromCache($cacheKey);
+		if(!is_null($memberOfGroups)) {
+			return $memberOfGroups;
 		}
 		$groupDNs = $this->access->readAttribute($this->getDN(), 'memberOf');
 		$this->connection->writeToCache($cacheKey, $groupDNs);