nextcloud / server

apps/user_ldap/lib/Connection.php

Indentation +611 added lines, -611 removed lines

@@ -75,615 +75,615 @@
  * @property string ldapMatchingRuleInChainState
  */
 class Connection extends LDAPUtility {
-	private $ldapConnectionRes = null;
-	private $configPrefix;
-	private $configID;
-	private $configured = false;
-	//whether connection should be kept on __destruct
-	private $dontDestruct = false;
-
-	/**
-	 * @var bool runtime flag that indicates whether supported primary groups are available
-	 */
-	public $hasPrimaryGroups = true;
-
-	/**
-	 * @var bool runtime flag that indicates whether supported POSIX gidNumber are available
-	 */
-	public $hasGidNumber = true;
-
-	//cache handler
-	protected $cache;
-
-	/** @var Configuration settings handler **/
-	protected $configuration;
-
-	protected $doNotValidate = false;
-
-	protected $ignoreValidation = false;
-
-	protected $bindResult = [];
-
-	/**
-	 * Constructor
-	 * @param ILDAPWrapper $ldap
-	 * @param string $configPrefix a string with the prefix for the configkey column (appconfig table)
-	 * @param string|null $configID a string with the value for the appid column (appconfig table) or null for on-the-fly connections
-	 */
-	public function __construct(ILDAPWrapper $ldap, $configPrefix = '', $configID = 'user_ldap') {
-		parent::__construct($ldap);
-		$this->configPrefix = $configPrefix;
-		$this->configID = $configID;
-		$this->configuration = new Configuration($configPrefix,
-												 !is_null($configID));
-		$memcache = \OC::$server->getMemCacheFactory();
-		if ($memcache->isAvailable()) {
-			$this->cache = $memcache->createDistributed();
-		}
-		$helper = new Helper(\OC::$server->getConfig());
-		$this->doNotValidate = !in_array($this->configPrefix,
-			$helper->getServerConfigurationPrefixes());
-	}
-
-	public function __destruct() {
-		if (!$this->dontDestruct && $this->ldap->isResource($this->ldapConnectionRes)) {
-			@$this->ldap->unbind($this->ldapConnectionRes);
-			$this->bindResult = [];
-		}
-	}
-
-	/**
-	 * defines behaviour when the instance is cloned
-	 */
-	public function __clone() {
-		$this->configuration = new Configuration($this->configPrefix,
-												 !is_null($this->configID));
-		if (count($this->bindResult) !== 0 && $this->bindResult['result'] === true) {
-			$this->bindResult = [];
-		}
-		$this->ldapConnectionRes = null;
-		$this->dontDestruct = true;
-	}
-
-	public function __get(string $name) {
-		if (!$this->configured) {
-			$this->readConfiguration();
-		}
-
-		return $this->configuration->$name;
-	}
-
-	/**
-	 * @param string $name
-	 * @param mixed $value
-	 */
-	public function __set($name, $value) {
-		$this->doNotValidate = false;
-		$before = $this->configuration->$name;
-		$this->configuration->$name = $value;
-		$after = $this->configuration->$name;
-		if ($before !== $after) {
-			if ($this->configID !== '' && $this->configID !== null) {
-				$this->configuration->saveConfiguration();
-			}
-			$this->validateConfiguration();
-		}
-	}
-
-	/**
-	 * @param string $rule
-	 * @return array
-	 * @throws \RuntimeException
-	 */
-	public function resolveRule($rule) {
-		return $this->configuration->resolveRule($rule);
-	}
-
-	/**
-	 * sets whether the result of the configuration validation shall
-	 * be ignored when establishing the connection. Used by the Wizard
-	 * in early configuration state.
-	 * @param bool $state
-	 */
-	public function setIgnoreValidation($state) {
-		$this->ignoreValidation = (bool)$state;
-	}
-
-	/**
-	 * initializes the LDAP backend
-	 * @param bool $force read the config settings no matter what
-	 */
-	public function init($force = false) {
-		$this->readConfiguration($force);
-		$this->establishConnection();
-	}
-
-	/**
-	 * Returns the LDAP handler
-	 */
-	public function getConnectionResource() {
-		if (!$this->ldapConnectionRes) {
-			$this->init();
-		} elseif (!$this->ldap->isResource($this->ldapConnectionRes)) {
-			$this->ldapConnectionRes = null;
-			$this->establishConnection();
-		}
-		if (is_null($this->ldapConnectionRes)) {
-			\OCP\Util::writeLog('user_ldap', 'No LDAP Connection to server ' . $this->configuration->ldapHost, ILogger::ERROR);
-			throw new ServerNotAvailableException('Connection to LDAP server could not be established');
-		}
-		return $this->ldapConnectionRes;
-	}
-
-	/**
-	 * resets the connection resource
-	 */
-	public function resetConnectionResource() {
-		if (!is_null($this->ldapConnectionRes)) {
-			@$this->ldap->unbind($this->ldapConnectionRes);
-			$this->ldapConnectionRes = null;
-			$this->bindResult = [];
-		}
-	}
-
-	/**
-	 * @param string|null $key
-	 * @return string
-	 */
-	private function getCacheKey($key) {
-		$prefix = 'LDAP-'.$this->configID.'-'.$this->configPrefix.'-';
-		if (is_null($key)) {
-			return $prefix;
-		}
-		return $prefix.hash('sha256', $key);
-	}
-
-	/**
-	 * @param string $key
-	 * @return mixed|null
-	 */
-	public function getFromCache($key) {
-		if (!$this->configured) {
-			$this->readConfiguration();
-		}
-		if (is_null($this->cache) || !$this->configuration->ldapCacheTTL) {
-			return null;
-		}
-		$key = $this->getCacheKey($key);
-
-		return json_decode(base64_decode($this->cache->get($key)), true);
-	}
-
-	/**
-	 * @param string $key
-	 * @param mixed $value
-	 *
-	 * @return string
-	 */
-	public function writeToCache($key, $value) {
-		if (!$this->configured) {
-			$this->readConfiguration();
-		}
-		if (is_null($this->cache)
-			|| !$this->configuration->ldapCacheTTL
-			|| !$this->configuration->ldapConfigurationActive) {
-			return null;
-		}
-		$key = $this->getCacheKey($key);
-		$value = base64_encode(json_encode($value));
-		$this->cache->set($key, $value, $this->configuration->ldapCacheTTL);
-	}
-
-	public function clearCache() {
-		if (!is_null($this->cache)) {
-			$this->cache->clear($this->getCacheKey(null));
-		}
-	}
-
-	/**
-	 * Caches the general LDAP configuration.
-	 * @param bool $force optional. true, if the re-read should be forced. defaults
-	 * to false.
-	 * @return null
-	 */
-	private function readConfiguration($force = false) {
-		if ((!$this->configured || $force) && !is_null($this->configID)) {
-			$this->configuration->readConfiguration();
-			$this->configured = $this->validateConfiguration();
-		}
-	}
-
-	/**
-	 * set LDAP configuration with values delivered by an array, not read from configuration
-	 * @param array $config array that holds the config parameters in an associated array
-	 * @param array &$setParameters optional; array where the set fields will be given to
-	 * @return boolean true if config validates, false otherwise. Check with $setParameters for detailed success on single parameters
-	 */
-	public function setConfiguration($config, &$setParameters = null) {
-		if (is_null($setParameters)) {
-			$setParameters = [];
-		}
-		$this->doNotValidate = false;
-		$this->configuration->setConfiguration($config, $setParameters);
-		if (count($setParameters) > 0) {
-			$this->configured = $this->validateConfiguration();
-		}
-
-
-		return $this->configured;
-	}
-
-	/**
-	 * saves the current Configuration in the database and empties the
-	 * cache
-	 * @return null
-	 */
-	public function saveConfiguration() {
-		$this->configuration->saveConfiguration();
-		$this->clearCache();
-	}
-
-	/**
-	 * get the current LDAP configuration
-	 * @return array
-	 */
-	public function getConfiguration() {
-		$this->readConfiguration();
-		$config = $this->configuration->getConfiguration();
-		$cta = $this->configuration->getConfigTranslationArray();
-		$result = [];
-		foreach ($cta as $dbkey => $configkey) {
-			switch ($configkey) {
-				case 'homeFolderNamingRule':
-					if (strpos($config[$configkey], 'attr:') === 0) {
-						$result[$dbkey] = substr($config[$configkey], 5);
-					} else {
-						$result[$dbkey] = '';
-					}
-					break;
-				case 'ldapBase':
-				case 'ldapBaseUsers':
-				case 'ldapBaseGroups':
-				case 'ldapAttributesForUserSearch':
-				case 'ldapAttributesForGroupSearch':
-					if (is_array($config[$configkey])) {
-						$result[$dbkey] = implode("\n", $config[$configkey]);
-						break;
-					} //else follows default
-					// no break
-				default:
-					$result[$dbkey] = $config[$configkey];
-			}
-		}
-		return $result;
-	}
-
-	private function doSoftValidation() {
-		//if User or Group Base are not set, take over Base DN setting
-		foreach (['ldapBaseUsers', 'ldapBaseGroups'] as $keyBase) {
-			$val = $this->configuration->$keyBase;
-			if (empty($val)) {
-				$this->configuration->$keyBase = $this->configuration->ldapBase;
-			}
-		}
-
-		foreach (['ldapExpertUUIDUserAttr' => 'ldapUuidUserAttribute',
-			'ldapExpertUUIDGroupAttr' => 'ldapUuidGroupAttribute']
-				as $expertSetting => $effectiveSetting) {
-			$uuidOverride = $this->configuration->$expertSetting;
-			if (!empty($uuidOverride)) {
-				$this->configuration->$effectiveSetting = $uuidOverride;
-			} else {
-				$uuidAttributes = Access::UUID_ATTRIBUTES;
-				array_unshift($uuidAttributes, 'auto');
-				if (!in_array($this->configuration->$effectiveSetting,
-							$uuidAttributes)
-					&& (!is_null($this->configID))) {
-					$this->configuration->$effectiveSetting = 'auto';
-					$this->configuration->saveConfiguration();
-					\OCP\Util::writeLog('user_ldap',
-										'Illegal value for the '.
-										$effectiveSetting.', '.'reset to '.
-										'autodetect.', ILogger::INFO);
-				}
-			}
-		}
-
-		$backupPort = (int)$this->configuration->ldapBackupPort;
-		if ($backupPort <= 0) {
-			$this->configuration->backupPort = $this->configuration->ldapPort;
-		}
-
-		//make sure empty search attributes are saved as simple, empty array
-		$saKeys = ['ldapAttributesForUserSearch',
-			'ldapAttributesForGroupSearch'];
-		foreach ($saKeys as $key) {
-			$val = $this->configuration->$key;
-			if (is_array($val) && count($val) === 1 && empty($val[0])) {
-				$this->configuration->$key = [];
-			}
-		}
-
-		if ((stripos($this->configuration->ldapHost, 'ldaps://') === 0)
-			&& $this->configuration->ldapTLS) {
-			$this->configuration->ldapTLS = false;
-			\OCP\Util::writeLog(
-				'user_ldap',
-				'LDAPS (already using secure connection) and TLS do not work together. Switched off TLS.',
-				ILogger::INFO
-			);
-		}
-	}
-
-	/**
-	 * @return bool
-	 */
-	private function doCriticalValidation() {
-		$configurationOK = true;
-		$errorStr = 'Configuration Error (prefix '.
-			(string)$this->configPrefix .'): ';
-
-		//options that shall not be empty
-		$options = ['ldapHost', 'ldapPort', 'ldapUserDisplayName',
-			'ldapGroupDisplayName', 'ldapLoginFilter'];
-		foreach ($options as $key) {
-			$val = $this->configuration->$key;
-			if (empty($val)) {
-				switch ($key) {
-					case 'ldapHost':
-						$subj = 'LDAP Host';
-						break;
-					case 'ldapPort':
-						$subj = 'LDAP Port';
-						break;
-					case 'ldapUserDisplayName':
-						$subj = 'LDAP User Display Name';
-						break;
-					case 'ldapGroupDisplayName':
-						$subj = 'LDAP Group Display Name';
-						break;
-					case 'ldapLoginFilter':
-						$subj = 'LDAP Login Filter';
-						break;
-					default:
-						$subj = $key;
-						break;
-				}
-				$configurationOK = false;
-				\OCP\Util::writeLog(
-					'user_ldap',
-					$errorStr.'No '.$subj.' given!',
-					ILogger::WARN
-				);
-			}
-		}
-
-		//combinations
-		$agent = $this->configuration->ldapAgentName;
-		$pwd = $this->configuration->ldapAgentPassword;
-		if (
-			($agent === '' && $pwd !== '')
-			|| ($agent !== '' && $pwd === '')
-		) {
-			\OCP\Util::writeLog(
-				'user_ldap',
-				$errorStr.'either no password is given for the user ' .
-					'agent or a password is given, but not an LDAP agent.',
-				ILogger::WARN);
-			$configurationOK = false;
-		}
-
-		$base = $this->configuration->ldapBase;
-		$baseUsers = $this->configuration->ldapBaseUsers;
-		$baseGroups = $this->configuration->ldapBaseGroups;
-
-		if (empty($base) && empty($baseUsers) && empty($baseGroups)) {
-			\OCP\Util::writeLog(
-				'user_ldap',
-				$errorStr.'Not a single Base DN given.',
-				ILogger::WARN
-			);
-			$configurationOK = false;
-		}
-
-		if (mb_strpos($this->configuration->ldapLoginFilter, '%uid', 0, 'UTF-8')
-		   === false) {
-			\OCP\Util::writeLog(
-				'user_ldap',
-				$errorStr.'login filter does not contain %uid place holder.',
-				ILogger::WARN
-			);
-			$configurationOK = false;
-		}
-
-		return $configurationOK;
-	}
-
-	/**
-	 * Validates the user specified configuration
-	 * @return bool true if configuration seems OK, false otherwise
-	 */
-	private function validateConfiguration() {
-		if ($this->doNotValidate) {
-			//don't do a validation if it is a new configuration with pure
-			//default values. Will be allowed on changes via __set or
-			//setConfiguration
-			return false;
-		}
-
-		// first step: "soft" checks: settings that are not really
-		// necessary, but advisable. If left empty, give an info message
-		$this->doSoftValidation();
-
-		//second step: critical checks. If left empty or filled wrong, mark as
-		//not configured and give a warning.
-		return $this->doCriticalValidation();
-	}
-
-
-	/**
-	 * Connects and Binds to LDAP
-	 *
-	 * @throws ServerNotAvailableException
-	 */
-	private function establishConnection() {
-		if (!$this->configuration->ldapConfigurationActive) {
-			return null;
-		}
-		static $phpLDAPinstalled = true;
-		if (!$phpLDAPinstalled) {
-			return false;
-		}
-		if (!$this->ignoreValidation && !$this->configured) {
-			\OCP\Util::writeLog(
-				'user_ldap',
-				'Configuration is invalid, cannot connect',
-				ILogger::WARN
-			);
-			return false;
-		}
-		if (!$this->ldapConnectionRes) {
-			if (!$this->ldap->areLDAPFunctionsAvailable()) {
-				$phpLDAPinstalled = false;
-				\OCP\Util::writeLog(
-					'user_ldap',
-					'function ldap_connect is not available. Make sure that the PHP ldap module is installed.',
-					ILogger::ERROR
-				);
-
-				return false;
-			}
-			if ($this->configuration->turnOffCertCheck) {
-				if (putenv('LDAPTLS_REQCERT=never')) {
-					\OCP\Util::writeLog('user_ldap',
-						'Turned off SSL certificate validation successfully.',
-						ILogger::DEBUG);
-				} else {
-					\OCP\Util::writeLog(
-						'user_ldap',
-						'Could not turn off SSL certificate validation.',
-						ILogger::WARN
-					);
-				}
-			}
-
-			$isOverrideMainServer = ($this->configuration->ldapOverrideMainServer
-				|| $this->getFromCache('overrideMainServer'));
-			$isBackupHost = (trim($this->configuration->ldapBackupHost) !== "");
-			$bindStatus = false;
-			try {
-				if (!$isOverrideMainServer) {
-					$this->doConnect($this->configuration->ldapHost,
-						$this->configuration->ldapPort);
-					return $this->bind();
-				}
-			} catch (ServerNotAvailableException $e) {
-				if (!$isBackupHost) {
-					throw $e;
-				}
-			}
-
-			//if LDAP server is not reachable, try the Backup (Replica!) Server
-			if ($isBackupHost || $isOverrideMainServer) {
-				$this->doConnect($this->configuration->ldapBackupHost,
-								 $this->configuration->ldapBackupPort);
-				$this->bindResult = [];
-				$bindStatus = $this->bind();
-				$error = $this->ldap->isResource($this->ldapConnectionRes) ?
-					$this->ldap->errno($this->ldapConnectionRes) : -1;
-				if ($bindStatus && $error === 0 && !$this->getFromCache('overrideMainServer')) {
-					//when bind to backup server succeeded and failed to main server,
-					//skip contacting him until next cache refresh
-					$this->writeToCache('overrideMainServer', true);
-				}
-			}
-
-			return $bindStatus;
-		}
-		return null;
-	}
-
-	/**
-	 * @param string $host
-	 * @param string $port
-	 * @return bool
-	 * @throws \OC\ServerNotAvailableException
-	 */
-	private function doConnect($host, $port) {
-		if ($host === '') {
-			return false;
-		}
-
-		$this->ldapConnectionRes = $this->ldap->connect($host, $port);
-
-		if (!$this->ldap->setOption($this->ldapConnectionRes, LDAP_OPT_PROTOCOL_VERSION, 3)) {
-			throw new ServerNotAvailableException('Could not set required LDAP Protocol version.');
-		}
-
-		if (!$this->ldap->setOption($this->ldapConnectionRes, LDAP_OPT_REFERRALS, 0)) {
-			throw new ServerNotAvailableException('Could not disable LDAP referrals.');
-		}
-
-		if ($this->configuration->ldapTLS) {
-			if (!$this->ldap->startTls($this->ldapConnectionRes)) {
-				throw new ServerNotAvailableException('Start TLS failed, when connecting to LDAP host ' . $host . '.');
-			}
-		}
-
-		return true;
-	}
-
-	/**
-	 * Binds to LDAP
-	 */
-	public function bind() {
-		if (!$this->configuration->ldapConfigurationActive) {
-			return false;
-		}
-		$cr = $this->ldapConnectionRes;
-		if (!$this->ldap->isResource($cr)) {
-			$cr = $this->getConnectionResource();
-		}
-
-		if (
-			count($this->bindResult) !== 0
-			&& $this->bindResult['dn'] === $this->configuration->ldapAgentName
-			&& \OC::$server->getHasher()->verify(
-				$this->configPrefix . $this->configuration->ldapAgentPassword,
-				$this->bindResult['hash']
-			)
-		) {
-			// don't attempt to bind again with the same data as before
-			// bind might have been invoked via getConnectionResource(),
-			// but we need results specifically for e.g. user login
-			return $this->bindResult['result'];
-		}
-
-		$ldapLogin = @$this->ldap->bind($cr,
-										$this->configuration->ldapAgentName,
-										$this->configuration->ldapAgentPassword);
-
-		$this->bindResult = [
-			'dn' => $this->configuration->ldapAgentName,
-			'hash' => \OC::$server->getHasher()->hash($this->configPrefix . $this->configuration->ldapAgentPassword),
-			'result' => $ldapLogin,
-		];
-
-		if (!$ldapLogin) {
-			$errno = $this->ldap->errno($cr);
-
-			\OCP\Util::writeLog('user_ldap',
-				'Bind failed: ' . $errno . ': ' . $this->ldap->error($cr),
-				ILogger::WARN);
-
-			// Set to failure mode, if LDAP error code is not LDAP_SUCCESS or LDAP_INVALID_CREDENTIALS
-			// or (needed for Apple Open Directory:) LDAP_INSUFFICIENT_ACCESS
-			if ($errno !== 0 && $errno !== 49 && $errno !== 50) {
-				$this->ldapConnectionRes = null;
-			}
-
-			return false;
-		}
-		return true;
-	}
+    private $ldapConnectionRes = null;
+    private $configPrefix;
+    private $configID;
+    private $configured = false;
+    //whether connection should be kept on __destruct
+    private $dontDestruct = false;
+
+    /**
+     * @var bool runtime flag that indicates whether supported primary groups are available
+     */
+    public $hasPrimaryGroups = true;
+
+    /**
+     * @var bool runtime flag that indicates whether supported POSIX gidNumber are available
+     */
+    public $hasGidNumber = true;
+
+    //cache handler
+    protected $cache;
+
+    /** @var Configuration settings handler **/
+    protected $configuration;
+
+    protected $doNotValidate = false;
+
+    protected $ignoreValidation = false;
+
+    protected $bindResult = [];
+
+    /**
+     * Constructor
+     * @param ILDAPWrapper $ldap
+     * @param string $configPrefix a string with the prefix for the configkey column (appconfig table)
+     * @param string|null $configID a string with the value for the appid column (appconfig table) or null for on-the-fly connections
+     */
+    public function __construct(ILDAPWrapper $ldap, $configPrefix = '', $configID = 'user_ldap') {
+        parent::__construct($ldap);
+        $this->configPrefix = $configPrefix;
+        $this->configID = $configID;
+        $this->configuration = new Configuration($configPrefix,
+                                                    !is_null($configID));
+        $memcache = \OC::$server->getMemCacheFactory();
+        if ($memcache->isAvailable()) {
+            $this->cache = $memcache->createDistributed();
+        }
+        $helper = new Helper(\OC::$server->getConfig());
+        $this->doNotValidate = !in_array($this->configPrefix,
+            $helper->getServerConfigurationPrefixes());
+    }
+
+    public function __destruct() {
+        if (!$this->dontDestruct && $this->ldap->isResource($this->ldapConnectionRes)) {
+            @$this->ldap->unbind($this->ldapConnectionRes);
+            $this->bindResult = [];
+        }
+    }
+
+    /**
+     * defines behaviour when the instance is cloned
+     */
+    public function __clone() {
+        $this->configuration = new Configuration($this->configPrefix,
+                                                    !is_null($this->configID));
+        if (count($this->bindResult) !== 0 && $this->bindResult['result'] === true) {
+            $this->bindResult = [];
+        }
+        $this->ldapConnectionRes = null;
+        $this->dontDestruct = true;
+    }
+
+    public function __get(string $name) {
+        if (!$this->configured) {
+            $this->readConfiguration();
+        }
+
+        return $this->configuration->$name;
+    }
+
+    /**
+     * @param string $name
+     * @param mixed $value
+     */
+    public function __set($name, $value) {
+        $this->doNotValidate = false;
+        $before = $this->configuration->$name;
+        $this->configuration->$name = $value;
+        $after = $this->configuration->$name;
+        if ($before !== $after) {
+            if ($this->configID !== '' && $this->configID !== null) {
+                $this->configuration->saveConfiguration();
+            }
+            $this->validateConfiguration();
+        }
+    }
+
+    /**
+     * @param string $rule
+     * @return array
+     * @throws \RuntimeException
+     */
+    public function resolveRule($rule) {
+        return $this->configuration->resolveRule($rule);
+    }
+
+    /**
+     * sets whether the result of the configuration validation shall
+     * be ignored when establishing the connection. Used by the Wizard
+     * in early configuration state.
+     * @param bool $state
+     */
+    public function setIgnoreValidation($state) {
+        $this->ignoreValidation = (bool)$state;
+    }
+
+    /**
+     * initializes the LDAP backend
+     * @param bool $force read the config settings no matter what
+     */
+    public function init($force = false) {
+        $this->readConfiguration($force);
+        $this->establishConnection();
+    }
+
+    /**
+     * Returns the LDAP handler
+     */
+    public function getConnectionResource() {
+        if (!$this->ldapConnectionRes) {
+            $this->init();
+        } elseif (!$this->ldap->isResource($this->ldapConnectionRes)) {
+            $this->ldapConnectionRes = null;
+            $this->establishConnection();
+        }
+        if (is_null($this->ldapConnectionRes)) {
+            \OCP\Util::writeLog('user_ldap', 'No LDAP Connection to server ' . $this->configuration->ldapHost, ILogger::ERROR);
+            throw new ServerNotAvailableException('Connection to LDAP server could not be established');
+        }
+        return $this->ldapConnectionRes;
+    }
+
+    /**
+     * resets the connection resource
+     */
+    public function resetConnectionResource() {
+        if (!is_null($this->ldapConnectionRes)) {
+            @$this->ldap->unbind($this->ldapConnectionRes);
+            $this->ldapConnectionRes = null;
+            $this->bindResult = [];
+        }
+    }
+
+    /**
+     * @param string|null $key
+     * @return string
+     */
+    private function getCacheKey($key) {
+        $prefix = 'LDAP-'.$this->configID.'-'.$this->configPrefix.'-';
+        if (is_null($key)) {
+            return $prefix;
+        }
+        return $prefix.hash('sha256', $key);
+    }
+
+    /**
+     * @param string $key
+     * @return mixed|null
+     */
+    public function getFromCache($key) {
+        if (!$this->configured) {
+            $this->readConfiguration();
+        }
+        if (is_null($this->cache) || !$this->configuration->ldapCacheTTL) {
+            return null;
+        }
+        $key = $this->getCacheKey($key);
+
+        return json_decode(base64_decode($this->cache->get($key)), true);
+    }
+
+    /**
+     * @param string $key
+     * @param mixed $value
+     *
+     * @return string
+     */
+    public function writeToCache($key, $value) {
+        if (!$this->configured) {
+            $this->readConfiguration();
+        }
+        if (is_null($this->cache)
+            || !$this->configuration->ldapCacheTTL
+            || !$this->configuration->ldapConfigurationActive) {
+            return null;
+        }
+        $key = $this->getCacheKey($key);
+        $value = base64_encode(json_encode($value));
+        $this->cache->set($key, $value, $this->configuration->ldapCacheTTL);
+    }
+
+    public function clearCache() {
+        if (!is_null($this->cache)) {
+            $this->cache->clear($this->getCacheKey(null));
+        }
+    }
+
+    /**
+     * Caches the general LDAP configuration.
+     * @param bool $force optional. true, if the re-read should be forced. defaults
+     * to false.
+     * @return null
+     */
+    private function readConfiguration($force = false) {
+        if ((!$this->configured || $force) && !is_null($this->configID)) {
+            $this->configuration->readConfiguration();
+            $this->configured = $this->validateConfiguration();
+        }
+    }
+
+    /**
+     * set LDAP configuration with values delivered by an array, not read from configuration
+     * @param array $config array that holds the config parameters in an associated array
+     * @param array &$setParameters optional; array where the set fields will be given to
+     * @return boolean true if config validates, false otherwise. Check with $setParameters for detailed success on single parameters
+     */
+    public function setConfiguration($config, &$setParameters = null) {
+        if (is_null($setParameters)) {
+            $setParameters = [];
+        }
+        $this->doNotValidate = false;
+        $this->configuration->setConfiguration($config, $setParameters);
+        if (count($setParameters) > 0) {
+            $this->configured = $this->validateConfiguration();
+        }
+
+
+        return $this->configured;
+    }
+
+    /**
+     * saves the current Configuration in the database and empties the
+     * cache
+     * @return null
+     */
+    public function saveConfiguration() {
+        $this->configuration->saveConfiguration();
+        $this->clearCache();
+    }
+
+    /**
+     * get the current LDAP configuration
+     * @return array
+     */
+    public function getConfiguration() {
+        $this->readConfiguration();
+        $config = $this->configuration->getConfiguration();
+        $cta = $this->configuration->getConfigTranslationArray();
+        $result = [];
+        foreach ($cta as $dbkey => $configkey) {
+            switch ($configkey) {
+                case 'homeFolderNamingRule':
+                    if (strpos($config[$configkey], 'attr:') === 0) {
+                        $result[$dbkey] = substr($config[$configkey], 5);
+                    } else {
+                        $result[$dbkey] = '';
+                    }
+                    break;
+                case 'ldapBase':
+                case 'ldapBaseUsers':
+                case 'ldapBaseGroups':
+                case 'ldapAttributesForUserSearch':
+                case 'ldapAttributesForGroupSearch':
+                    if (is_array($config[$configkey])) {
+                        $result[$dbkey] = implode("\n", $config[$configkey]);
+                        break;
+                    } //else follows default
+                    // no break
+                default:
+                    $result[$dbkey] = $config[$configkey];
+            }
+        }
+        return $result;
+    }
+
+    private function doSoftValidation() {
+        //if User or Group Base are not set, take over Base DN setting
+        foreach (['ldapBaseUsers', 'ldapBaseGroups'] as $keyBase) {
+            $val = $this->configuration->$keyBase;
+            if (empty($val)) {
+                $this->configuration->$keyBase = $this->configuration->ldapBase;
+            }
+        }
+
+        foreach (['ldapExpertUUIDUserAttr' => 'ldapUuidUserAttribute',
+            'ldapExpertUUIDGroupAttr' => 'ldapUuidGroupAttribute']
+                as $expertSetting => $effectiveSetting) {
+            $uuidOverride = $this->configuration->$expertSetting;
+            if (!empty($uuidOverride)) {
+                $this->configuration->$effectiveSetting = $uuidOverride;
+            } else {
+                $uuidAttributes = Access::UUID_ATTRIBUTES;
+                array_unshift($uuidAttributes, 'auto');
+                if (!in_array($this->configuration->$effectiveSetting,
+                            $uuidAttributes)
+                    && (!is_null($this->configID))) {
+                    $this->configuration->$effectiveSetting = 'auto';
+                    $this->configuration->saveConfiguration();
+                    \OCP\Util::writeLog('user_ldap',
+                                        'Illegal value for the '.
+                                        $effectiveSetting.', '.'reset to '.
+                                        'autodetect.', ILogger::INFO);
+                }
+            }
+        }
+
+        $backupPort = (int)$this->configuration->ldapBackupPort;
+        if ($backupPort <= 0) {
+            $this->configuration->backupPort = $this->configuration->ldapPort;
+        }
+
+        //make sure empty search attributes are saved as simple, empty array
+        $saKeys = ['ldapAttributesForUserSearch',
+            'ldapAttributesForGroupSearch'];
+        foreach ($saKeys as $key) {
+            $val = $this->configuration->$key;
+            if (is_array($val) && count($val) === 1 && empty($val[0])) {
+                $this->configuration->$key = [];
+            }
+        }
+
+        if ((stripos($this->configuration->ldapHost, 'ldaps://') === 0)
+            && $this->configuration->ldapTLS) {
+            $this->configuration->ldapTLS = false;
+            \OCP\Util::writeLog(
+                'user_ldap',
+                'LDAPS (already using secure connection) and TLS do not work together. Switched off TLS.',
+                ILogger::INFO
+            );
+        }
+    }
+
+    /**
+     * @return bool
+     */
+    private function doCriticalValidation() {
+        $configurationOK = true;
+        $errorStr = 'Configuration Error (prefix '.
+            (string)$this->configPrefix .'): ';
+
+        //options that shall not be empty
+        $options = ['ldapHost', 'ldapPort', 'ldapUserDisplayName',
+            'ldapGroupDisplayName', 'ldapLoginFilter'];
+        foreach ($options as $key) {
+            $val = $this->configuration->$key;
+            if (empty($val)) {
+                switch ($key) {
+                    case 'ldapHost':
+                        $subj = 'LDAP Host';
+                        break;
+                    case 'ldapPort':
+                        $subj = 'LDAP Port';
+                        break;
+                    case 'ldapUserDisplayName':
+                        $subj = 'LDAP User Display Name';
+                        break;
+                    case 'ldapGroupDisplayName':
+                        $subj = 'LDAP Group Display Name';
+                        break;
+                    case 'ldapLoginFilter':
+                        $subj = 'LDAP Login Filter';
+                        break;
+                    default:
+                        $subj = $key;
+                        break;
+                }
+                $configurationOK = false;
+                \OCP\Util::writeLog(
+                    'user_ldap',
+                    $errorStr.'No '.$subj.' given!',
+                    ILogger::WARN
+                );
+            }
+        }
+
+        //combinations
+        $agent = $this->configuration->ldapAgentName;
+        $pwd = $this->configuration->ldapAgentPassword;
+        if (
+            ($agent === '' && $pwd !== '')
+            || ($agent !== '' && $pwd === '')
+        ) {
+            \OCP\Util::writeLog(
+                'user_ldap',
+                $errorStr.'either no password is given for the user ' .
+                    'agent or a password is given, but not an LDAP agent.',
+                ILogger::WARN);
+            $configurationOK = false;
+        }
+
+        $base = $this->configuration->ldapBase;
+        $baseUsers = $this->configuration->ldapBaseUsers;
+        $baseGroups = $this->configuration->ldapBaseGroups;
+
+        if (empty($base) && empty($baseUsers) && empty($baseGroups)) {
+            \OCP\Util::writeLog(
+                'user_ldap',
+                $errorStr.'Not a single Base DN given.',
+                ILogger::WARN
+            );
+            $configurationOK = false;
+        }
+
+        if (mb_strpos($this->configuration->ldapLoginFilter, '%uid', 0, 'UTF-8')
+            === false) {
+            \OCP\Util::writeLog(
+                'user_ldap',
+                $errorStr.'login filter does not contain %uid place holder.',
+                ILogger::WARN
+            );
+            $configurationOK = false;
+        }
+
+        return $configurationOK;
+    }
+
+    /**
+     * Validates the user specified configuration
+     * @return bool true if configuration seems OK, false otherwise
+     */
+    private function validateConfiguration() {
+        if ($this->doNotValidate) {
+            //don't do a validation if it is a new configuration with pure
+            //default values. Will be allowed on changes via __set or
+            //setConfiguration
+            return false;
+        }
+
+        // first step: "soft" checks: settings that are not really
+        // necessary, but advisable. If left empty, give an info message
+        $this->doSoftValidation();
+
+        //second step: critical checks. If left empty or filled wrong, mark as
+        //not configured and give a warning.
+        return $this->doCriticalValidation();
+    }
+
+
+    /**
+     * Connects and Binds to LDAP
+     *
+     * @throws ServerNotAvailableException
+     */
+    private function establishConnection() {
+        if (!$this->configuration->ldapConfigurationActive) {
+            return null;
+        }
+        static $phpLDAPinstalled = true;
+        if (!$phpLDAPinstalled) {
+            return false;
+        }
+        if (!$this->ignoreValidation && !$this->configured) {
+            \OCP\Util::writeLog(
+                'user_ldap',
+                'Configuration is invalid, cannot connect',
+                ILogger::WARN
+            );
+            return false;
+        }
+        if (!$this->ldapConnectionRes) {
+            if (!$this->ldap->areLDAPFunctionsAvailable()) {
+                $phpLDAPinstalled = false;
+                \OCP\Util::writeLog(
+                    'user_ldap',
+                    'function ldap_connect is not available. Make sure that the PHP ldap module is installed.',
+                    ILogger::ERROR
+                );
+
+                return false;
+            }
+            if ($this->configuration->turnOffCertCheck) {
+                if (putenv('LDAPTLS_REQCERT=never')) {
+                    \OCP\Util::writeLog('user_ldap',
+                        'Turned off SSL certificate validation successfully.',
+                        ILogger::DEBUG);
+                } else {
+                    \OCP\Util::writeLog(
+                        'user_ldap',
+                        'Could not turn off SSL certificate validation.',
+                        ILogger::WARN
+                    );
+                }
+            }
+
+            $isOverrideMainServer = ($this->configuration->ldapOverrideMainServer
+                || $this->getFromCache('overrideMainServer'));
+            $isBackupHost = (trim($this->configuration->ldapBackupHost) !== "");
+            $bindStatus = false;
+            try {
+                if (!$isOverrideMainServer) {
+                    $this->doConnect($this->configuration->ldapHost,
+                        $this->configuration->ldapPort);
+                    return $this->bind();
+                }
+            } catch (ServerNotAvailableException $e) {
+                if (!$isBackupHost) {
+                    throw $e;
+                }
+            }
+
+            //if LDAP server is not reachable, try the Backup (Replica!) Server
+            if ($isBackupHost || $isOverrideMainServer) {
+                $this->doConnect($this->configuration->ldapBackupHost,
+                                    $this->configuration->ldapBackupPort);
+                $this->bindResult = [];
+                $bindStatus = $this->bind();
+                $error = $this->ldap->isResource($this->ldapConnectionRes) ?
+                    $this->ldap->errno($this->ldapConnectionRes) : -1;
+                if ($bindStatus && $error === 0 && !$this->getFromCache('overrideMainServer')) {
+                    //when bind to backup server succeeded and failed to main server,
+                    //skip contacting him until next cache refresh
+                    $this->writeToCache('overrideMainServer', true);
+                }
+            }
+
+            return $bindStatus;
+        }
+        return null;
+    }
+
+    /**
+     * @param string $host
+     * @param string $port
+     * @return bool
+     * @throws \OC\ServerNotAvailableException
+     */
+    private function doConnect($host, $port) {
+        if ($host === '') {
+            return false;
+        }
+
+        $this->ldapConnectionRes = $this->ldap->connect($host, $port);
+
+        if (!$this->ldap->setOption($this->ldapConnectionRes, LDAP_OPT_PROTOCOL_VERSION, 3)) {
+            throw new ServerNotAvailableException('Could not set required LDAP Protocol version.');
+        }
+
+        if (!$this->ldap->setOption($this->ldapConnectionRes, LDAP_OPT_REFERRALS, 0)) {
+            throw new ServerNotAvailableException('Could not disable LDAP referrals.');
+        }
+
+        if ($this->configuration->ldapTLS) {
+            if (!$this->ldap->startTls($this->ldapConnectionRes)) {
+                throw new ServerNotAvailableException('Start TLS failed, when connecting to LDAP host ' . $host . '.');
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * Binds to LDAP
+     */
+    public function bind() {
+        if (!$this->configuration->ldapConfigurationActive) {
+            return false;
+        }
+        $cr = $this->ldapConnectionRes;
+        if (!$this->ldap->isResource($cr)) {
+            $cr = $this->getConnectionResource();
+        }
+
+        if (
+            count($this->bindResult) !== 0
+            && $this->bindResult['dn'] === $this->configuration->ldapAgentName
+            && \OC::$server->getHasher()->verify(
+                $this->configPrefix . $this->configuration->ldapAgentPassword,
+                $this->bindResult['hash']
+            )
+        ) {
+            // don't attempt to bind again with the same data as before
+            // bind might have been invoked via getConnectionResource(),
+            // but we need results specifically for e.g. user login
+            return $this->bindResult['result'];
+        }
+
+        $ldapLogin = @$this->ldap->bind($cr,
+                                        $this->configuration->ldapAgentName,
+                                        $this->configuration->ldapAgentPassword);
+
+        $this->bindResult = [
+            'dn' => $this->configuration->ldapAgentName,
+            'hash' => \OC::$server->getHasher()->hash($this->configPrefix . $this->configuration->ldapAgentPassword),
+            'result' => $ldapLogin,
+        ];
+
+        if (!$ldapLogin) {
+            $errno = $this->ldap->errno($cr);
+
+            \OCP\Util::writeLog('user_ldap',
+                'Bind failed: ' . $errno . ': ' . $this->ldap->error($cr),
+                ILogger::WARN);
+
+            // Set to failure mode, if LDAP error code is not LDAP_SUCCESS or LDAP_INVALID_CREDENTIALS
+            // or (needed for Apple Open Directory:) LDAP_INSUFFICIENT_ACCESS
+            if ($errno !== 0 && $errno !== 49 && $errno !== 50) {
+                $this->ldapConnectionRes = null;
+            }
+
+            return false;
+        }
+        return true;
+    }
 }

apps/user_ldap/lib/Group_LDAP.php

Indentation +1268 added lines, -1268 removed lines

@@ -53,1272 +53,1272 @@
 use OCP\ILogger;
 
 class Group_LDAP extends BackendUtility implements GroupInterface, IGroupLDAP, IGetDisplayNameBackend {
-	protected $enabled = false;
-
-	/** @var string[] $cachedGroupMembers array of users with gid as key */
-	protected $cachedGroupMembers;
-	/** @var string[] $cachedGroupsByMember array of groups with uid as key */
-	protected $cachedGroupsByMember;
-	/** @var string[] $cachedNestedGroups array of groups with gid (DN) as key */
-	protected $cachedNestedGroups;
-	/** @var GroupPluginManager */
-	protected $groupPluginManager;
-	/** @var ILogger */
-	protected $logger;
-
-	/**
-	 * @var string $ldapGroupMemberAssocAttr contains the LDAP setting (in lower case) with the same name
-	 */
-	protected $ldapGroupMemberAssocAttr;
-
-	public function __construct(Access $access, GroupPluginManager $groupPluginManager) {
-		parent::__construct($access);
-		$filter = $this->access->connection->ldapGroupFilter;
-		$gAssoc = $this->access->connection->ldapGroupMemberAssocAttr;
-		if (!empty($filter) && !empty($gAssoc)) {
-			$this->enabled = true;
-		}
-
-		$this->cachedGroupMembers = new CappedMemoryCache();
-		$this->cachedGroupsByMember = new CappedMemoryCache();
-		$this->cachedNestedGroups = new CappedMemoryCache();
-		$this->groupPluginManager = $groupPluginManager;
-		$this->logger = OC::$server->getLogger();
-		$this->ldapGroupMemberAssocAttr = strtolower($gAssoc);
-	}
-
-	/**
-	 * is user in group?
-	 *
-	 * @param string $uid uid of the user
-	 * @param string $gid gid of the group
-	 * @return bool
-	 * @throws Exception
-	 * @throws ServerNotAvailableException
-	 */
-	public function inGroup($uid, $gid) {
-		if (!$this->enabled) {
-			return false;
-		}
-		$cacheKey = 'inGroup' . $uid . ':' . $gid;
-		$inGroup = $this->access->connection->getFromCache($cacheKey);
-		if (!is_null($inGroup)) {
-			return (bool)$inGroup;
-		}
-
-		$userDN = $this->access->username2dn($uid);
-
-		if (isset($this->cachedGroupMembers[$gid])) {
-			return in_array($userDN, $this->cachedGroupMembers[$gid]);
-		}
-
-		$cacheKeyMembers = 'inGroup-members:' . $gid;
-		$members = $this->access->connection->getFromCache($cacheKeyMembers);
-		if (!is_null($members)) {
-			$this->cachedGroupMembers[$gid] = $members;
-			$isInGroup = in_array($userDN, $members, true);
-			$this->access->connection->writeToCache($cacheKey, $isInGroup);
-			return $isInGroup;
-		}
-
-		$groupDN = $this->access->groupname2dn($gid);
-		// just in case
-		if (!$groupDN || !$userDN) {
-			$this->access->connection->writeToCache($cacheKey, false);
-			return false;
-		}
-
-		//check primary group first
-		if ($gid === $this->getUserPrimaryGroup($userDN)) {
-			$this->access->connection->writeToCache($cacheKey, true);
-			return true;
-		}
-
-		//usually, LDAP attributes are said to be case insensitive. But there are exceptions of course.
-		$members = $this->_groupMembers($groupDN);
-		if (!is_array($members) || count($members) === 0) {
-			$this->access->connection->writeToCache($cacheKey, false);
-			return false;
-		}
-
-		//extra work if we don't get back user DNs
-		switch ($this->ldapGroupMemberAssocAttr) {
-			case 'memberuid':
-			case 'zimbramailforwardingaddress':
-				$requestAttributes = $this->access->userManager->getAttributes(true);
-				$dns = [];
-				$filterParts = [];
-				$bytes = 0;
-				foreach ($members as $mid) {
-					if ($this->ldapGroupMemberAssocAttr === 'zimbramailforwardingaddress') {
-						$parts = explode('@', $mid); //making sure we get only the uid
-						$mid = $parts[0];
-					}
-					$filter = str_replace('%uid', $mid, $this->access->connection->ldapLoginFilter);
-					$filterParts[] = $filter;
-					$bytes += strlen($filter);
-					if ($bytes >= 9000000) {
-						// AD has a default input buffer of 10 MB, we do not want
-						// to take even the chance to exceed it
-						$filter = $this->access->combineFilterWithOr($filterParts);
-						$users = $this->access->fetchListOfUsers($filter, $requestAttributes, count($filterParts));
-						$bytes = 0;
-						$filterParts = [];
-						$dns = array_merge($dns, $users);
-					}
-				}
-				if (count($filterParts) > 0) {
-					$filter = $this->access->combineFilterWithOr($filterParts);
-					$users = $this->access->fetchListOfUsers($filter, $requestAttributes, count($filterParts));
-					$dns = array_merge($dns, $users);
-				}
-				$members = $dns;
-				break;
-		}
-
-		$isInGroup = in_array($userDN, $members);
-		$this->access->connection->writeToCache($cacheKey, $isInGroup);
-		$this->access->connection->writeToCache($cacheKeyMembers, $members);
-		$this->cachedGroupMembers[$gid] = $members;
-
-		return $isInGroup;
-	}
-
-	/**
-	 * For a group that has user membership defined by an LDAP search url
-	 * attribute returns the users that match the search url otherwise returns
-	 * an empty array.
-	 *
-	 * @throws ServerNotAvailableException
-	 */
-	public function getDynamicGroupMembers(string $dnGroup): array {
-		$dynamicGroupMemberURL = strtolower($this->access->connection->ldapDynamicGroupMemberURL);
-
-		if (empty($dynamicGroupMemberURL)) {
-			return [];
-		}
-
-		$dynamicMembers = [];
-		$memberURLs = $this->access->readAttribute(
-			$dnGroup,
-			$dynamicGroupMemberURL,
-			$this->access->connection->ldapGroupFilter
-		);
-		if ($memberURLs !== false) {
-			// this group has the 'memberURL' attribute so this is a dynamic group
-			// example 1: ldap:///cn=users,cn=accounts,dc=dcsubbase,dc=dcbase??one?(o=HeadOffice)
-			// example 2: ldap:///cn=users,cn=accounts,dc=dcsubbase,dc=dcbase??one?(&(o=HeadOffice)(uidNumber>=500))
-			$pos = strpos($memberURLs[0], '(');
-			if ($pos !== false) {
-				$memberUrlFilter = substr($memberURLs[0], $pos);
-				$foundMembers = $this->access->searchUsers($memberUrlFilter, 'dn');
-				$dynamicMembers = [];
-				foreach ($foundMembers as $value) {
-					$dynamicMembers[$value['dn'][0]] = 1;
-				}
-			} else {
-				$this->logger->debug('No search filter found on member url of group {dn}',
-					[
-						'app' => 'user_ldap',
-						'dn' => $dnGroup,
-					]
-				);
-			}
-		}
-		return $dynamicMembers;
-	}
-
-	/**
-	 * @throws ServerNotAvailableException
-	 */
-	private function _groupMembers(string $dnGroup, ?array &$seen = null): array {
-		if ($seen === null) {
-			$seen = [];
-		}
-		$allMembers = [];
-		if (array_key_exists($dnGroup, $seen)) {
-			return [];
-		}
-		// used extensively in cron job, caching makes sense for nested groups
-		$cacheKey = '_groupMembers' . $dnGroup;
-		$groupMembers = $this->access->connection->getFromCache($cacheKey);
-		if ($groupMembers !== null) {
-			return $groupMembers;
-		}
-
-		if ($this->access->connection->ldapNestedGroups
-			&& $this->access->connection->useMemberOfToDetectMembership
-			&& $this->access->connection->hasMemberOfFilterSupport
-			&& $this->access->connection->ldapMatchingRuleInChainState !== Configuration::LDAP_SERVER_FEATURE_UNAVAILABLE
-		) {
-			$attemptedLdapMatchingRuleInChain = true;
-			// compatibility hack with servers supporting :1.2.840.113556.1.4.1941:, and others)
-			$filter = $this->access->combineFilterWithAnd([
-				$this->access->connection->ldapUserFilter,
-				$this->access->connection->ldapUserDisplayName . '=*',
-				'memberof:1.2.840.113556.1.4.1941:=' . $dnGroup
-			]);
-			$memberRecords = $this->access->fetchListOfUsers(
-				$filter,
-				$this->access->userManager->getAttributes(true)
-			);
-			$result = array_reduce($memberRecords, function ($carry, $record) {
-				$carry[] = $record['dn'][0];
-				return $carry;
-			}, []);
-			if ($this->access->connection->ldapMatchingRuleInChainState === Configuration::LDAP_SERVER_FEATURE_AVAILABLE) {
-				return $result;
-			} elseif (!empty($memberRecords)) {
-				$this->access->connection->ldapMatchingRuleInChainState = Configuration::LDAP_SERVER_FEATURE_AVAILABLE;
-				$this->access->connection->saveConfiguration();
-				return $result;
-			}
-			// when feature availability is unknown, and the result is empty, continue and test with original approach
-		}
-
-		$seen[$dnGroup] = 1;
-		$members = $this->access->readAttribute($dnGroup, $this->access->connection->ldapGroupMemberAssocAttr);
-		if (is_array($members)) {
-			$fetcher = function ($memberDN, &$seen) {
-				return $this->_groupMembers($memberDN, $seen);
-			};
-			$allMembers = $this->walkNestedGroups($dnGroup, $fetcher, $members);
-		}
-
-		$allMembers += $this->getDynamicGroupMembers($dnGroup);
-
-		$this->access->connection->writeToCache($cacheKey, $allMembers);
-		if (isset($attemptedLdapMatchingRuleInChain)
-			&& $this->access->connection->ldapMatchingRuleInChainState === Configuration::LDAP_SERVER_FEATURE_UNKNOWN
-			&& !empty($allMembers)
-		) {
-			$this->access->connection->ldapMatchingRuleInChainState = Configuration::LDAP_SERVER_FEATURE_UNAVAILABLE;
-			$this->access->connection->saveConfiguration();
-		}
-		return $allMembers;
-	}
-
-	/**
-	 * @throws ServerNotAvailableException
-	 */
-	private function _getGroupDNsFromMemberOf(string $dn): array {
-		$groups = $this->access->readAttribute($dn, 'memberOf');
-		if (!is_array($groups)) {
-			return [];
-		}
-
-		$fetcher = function ($groupDN) {
-			if (isset($this->cachedNestedGroups[$groupDN])) {
-				$nestedGroups = $this->cachedNestedGroups[$groupDN];
-			} else {
-				$nestedGroups = $this->access->readAttribute($groupDN, 'memberOf');
-				if (!is_array($nestedGroups)) {
-					$nestedGroups = [];
-				}
-				$this->cachedNestedGroups[$groupDN] = $nestedGroups;
-			}
-			return $nestedGroups;
-		};
-
-		$groups = $this->walkNestedGroups($dn, $fetcher, $groups);
-		return $this->filterValidGroups($groups);
-	}
-
-	private function walkNestedGroups(string $dn, Closure $fetcher, array $list): array {
-		$nesting = (int)$this->access->connection->ldapNestedGroups;
-		// depending on the input, we either have a list of DNs or a list of LDAP records
-		// also, the output expects either DNs or records. Testing the first element should suffice.
-		$recordMode = is_array($list) && isset($list[0]) && is_array($list[0]) && isset($list[0]['dn'][0]);
-
-		if ($nesting !== 1) {
-			if ($recordMode) {
-				// the keys are numeric, but should hold the DN
-				return array_reduce($list, function ($transformed, $record) use ($dn) {
-					if ($record['dn'][0] != $dn) {
-						$transformed[$record['dn'][0]] = $record;
-					}
-					return $transformed;
-				}, []);
-			}
-			return $list;
-		}
-
-		$seen = [];
-		while ($record = array_shift($list)) {
-			$recordDN = $recordMode ? $record['dn'][0] : $record;
-			if ($recordDN === $dn || array_key_exists($recordDN, $seen)) {
-				// Prevent loops
-				continue;
-			}
-			$fetched = $fetcher($record, $seen);
-			$list = array_merge($list, $fetched);
-			$seen[$recordDN] = $record;
-		}
-
-		return $recordMode ? $seen : array_keys($seen);
-	}
-
-	/**
-	 * translates a gidNumber into an ownCloud internal name
-	 *
-	 * @return string|bool
-	 * @throws Exception
-	 * @throws ServerNotAvailableException
-	 */
-	public function gidNumber2Name(string $gid, string $dn) {
-		$cacheKey = 'gidNumberToName' . $gid;
-		$groupName = $this->access->connection->getFromCache($cacheKey);
-		if (!is_null($groupName) && isset($groupName)) {
-			return $groupName;
-		}
-
-		//we need to get the DN from LDAP
-		$filter = $this->access->combineFilterWithAnd([
-			$this->access->connection->ldapGroupFilter,
-			'objectClass=posixGroup',
-			$this->access->connection->ldapGidNumber . '=' . $gid
-		]);
-		return $this->getNameOfGroup($filter, $cacheKey) ?? false;
-	}
-
-	/**
-	 * @throws ServerNotAvailableException
-	 * @throws Exception
-	 */
-	private function getNameOfGroup(string $filter, string $cacheKey) {
-		$result = $this->access->searchGroups($filter, ['dn'], 1);
-		if (empty($result)) {
-			return null;
-		}
-		$dn = $result[0]['dn'][0];
-
-		//and now the group name
-		//NOTE once we have separate Nextcloud group IDs and group names we can
-		//directly read the display name attribute instead of the DN
-		$name = $this->access->dn2groupname($dn);
-
-		$this->access->connection->writeToCache($cacheKey, $name);
-
-		return $name;
-	}
-
-	/**
-	 * returns the entry's gidNumber
-	 *
-	 * @return string|bool
-	 * @throws ServerNotAvailableException
-	 */
-	private function getEntryGidNumber(string $dn, string $attribute) {
-		$value = $this->access->readAttribute($dn, $attribute);
-		if (is_array($value) && !empty($value)) {
-			return $value[0];
-		}
-		return false;
-	}
-
-	/**
-	 * @return string|bool
-	 * @throws ServerNotAvailableException
-	 */
-	public function getGroupGidNumber(string $dn) {
-		return $this->getEntryGidNumber($dn, 'gidNumber');
-	}
-
-	/**
-	 * returns the user's gidNumber
-	 *
-	 * @return string|bool
-	 * @throws ServerNotAvailableException
-	 */
-	public function getUserGidNumber(string $dn) {
-		$gidNumber = false;
-		if ($this->access->connection->hasGidNumber) {
-			$gidNumber = $this->getEntryGidNumber($dn, $this->access->connection->ldapGidNumber);
-			if ($gidNumber === false) {
-				$this->access->connection->hasGidNumber = false;
-			}
-		}
-		return $gidNumber;
-	}
-
-	/**
-	 * @throws ServerNotAvailableException
-	 * @throws Exception
-	 */
-	private function prepareFilterForUsersHasGidNumber(string $groupDN, string $search = ''): string {
-		$groupID = $this->getGroupGidNumber($groupDN);
-		if ($groupID === false) {
-			throw new Exception('Not a valid group');
-		}
-
-		$filterParts = [];
-		$filterParts[] = $this->access->getFilterForUserCount();
-		if ($search !== '') {
-			$filterParts[] = $this->access->getFilterPartForUserSearch($search);
-		}
-		$filterParts[] = $this->access->connection->ldapGidNumber . '=' . $groupID;
-
-		return $this->access->combineFilterWithAnd($filterParts);
-	}
-
-	/**
-	 * returns a list of users that have the given group as gid number
-	 *
-	 * @throws ServerNotAvailableException
-	 */
-	public function getUsersInGidNumber(
-		string $groupDN,
-		string $search = '',
-		?int $limit = -1,
-		?int $offset = 0
-	): array {
-		try {
-			$filter = $this->prepareFilterForUsersHasGidNumber($groupDN, $search);
-			$users = $this->access->fetchListOfUsers(
-				$filter,
-				[$this->access->connection->ldapUserDisplayName, 'dn'],
-				$limit,
-				$offset
-			);
-			return $this->access->nextcloudUserNames($users);
-		} catch (ServerNotAvailableException $e) {
-			throw $e;
-		} catch (Exception $e) {
-			return [];
-		}
-	}
-
-	/**
-	 * @throws ServerNotAvailableException
-	 * @return bool
-	 */
-	public function getUserGroupByGid(string $dn) {
-		$groupID = $this->getUserGidNumber($dn);
-		if ($groupID !== false) {
-			$groupName = $this->gidNumber2Name($groupID, $dn);
-			if ($groupName !== false) {
-				return $groupName;
-			}
-		}
-
-		return false;
-	}
-
-	/**
-	 * translates a primary group ID into an Nextcloud internal name
-	 *
-	 * @return string|bool
-	 * @throws Exception
-	 * @throws ServerNotAvailableException
-	 */
-	public function primaryGroupID2Name(string $gid, string $dn) {
-		$cacheKey = 'primaryGroupIDtoName';
-		$groupNames = $this->access->connection->getFromCache($cacheKey);
-		if (!is_null($groupNames) && isset($groupNames[$gid])) {
-			return $groupNames[$gid];
-		}
-
-		$domainObjectSid = $this->access->getSID($dn);
-		if ($domainObjectSid === false) {
-			return false;
-		}
-
-		//we need to get the DN from LDAP
-		$filter = $this->access->combineFilterWithAnd([
-			$this->access->connection->ldapGroupFilter,
-			'objectsid=' . $domainObjectSid . '-' . $gid
-		]);
-		return $this->getNameOfGroup($filter, $cacheKey) ?? false;
-	}
-
-	/**
-	 * returns the entry's primary group ID
-	 *
-	 * @return string|bool
-	 * @throws ServerNotAvailableException
-	 */
-	private function getEntryGroupID(string $dn, string $attribute) {
-		$value = $this->access->readAttribute($dn, $attribute);
-		if (is_array($value) && !empty($value)) {
-			return $value[0];
-		}
-		return false;
-	}
-
-	/**
-	 * @return string|bool
-	 * @throws ServerNotAvailableException
-	 */
-	public function getGroupPrimaryGroupID(string $dn) {
-		return $this->getEntryGroupID($dn, 'primaryGroupToken');
-	}
-
-	/**
-	 * @return string|bool
-	 * @throws ServerNotAvailableException
-	 */
-	public function getUserPrimaryGroupIDs(string $dn) {
-		$primaryGroupID = false;
-		if ($this->access->connection->hasPrimaryGroups) {
-			$primaryGroupID = $this->getEntryGroupID($dn, 'primaryGroupID');
-			if ($primaryGroupID === false) {
-				$this->access->connection->hasPrimaryGroups = false;
-			}
-		}
-		return $primaryGroupID;
-	}
-
-	/**
-	 * @throws Exception
-	 * @throws ServerNotAvailableException
-	 */
-	private function prepareFilterForUsersInPrimaryGroup(string $groupDN, string $search = ''): string {
-		$groupID = $this->getGroupPrimaryGroupID($groupDN);
-		if ($groupID === false) {
-			throw new Exception('Not a valid group');
-		}
-
-		$filterParts = [];
-		$filterParts[] = $this->access->getFilterForUserCount();
-		if ($search !== '') {
-			$filterParts[] = $this->access->getFilterPartForUserSearch($search);
-		}
-		$filterParts[] = 'primaryGroupID=' . $groupID;
-
-		return $this->access->combineFilterWithAnd($filterParts);
-	}
-
-	/**
-	 * @throws ServerNotAvailableException
-	 */
-	public function getUsersInPrimaryGroup(
-		string $groupDN,
-		string $search = '',
-		?int $limit = -1,
-		?int $offset = 0
-	): array {
-		try {
-			$filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
-			$users = $this->access->fetchListOfUsers(
-				$filter,
-				[$this->access->connection->ldapUserDisplayName, 'dn'],
-				$limit,
-				$offset
-			);
-			return $this->access->nextcloudUserNames($users);
-		} catch (ServerNotAvailableException $e) {
-			throw $e;
-		} catch (Exception $e) {
-			return [];
-		}
-	}
-
-	/**
-	 * @throws ServerNotAvailableException
-	 */
-	public function countUsersInPrimaryGroup(
-		string $groupDN,
-		string $search = '',
-		int $limit = -1,
-		int $offset = 0
-	): int {
-		try {
-			$filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
-			$users = $this->access->countUsers($filter, ['dn'], $limit, $offset);
-			return (int)$users;
-		} catch (ServerNotAvailableException $e) {
-			throw $e;
-		} catch (Exception $e) {
-			return 0;
-		}
-	}
-
-	/**
-	 * @return string|bool
-	 * @throws ServerNotAvailableException
-	 */
-	public function getUserPrimaryGroup(string $dn) {
-		$groupID = $this->getUserPrimaryGroupIDs($dn);
-		if ($groupID !== false) {
-			$groupName = $this->primaryGroupID2Name($groupID, $dn);
-			if ($groupName !== false) {
-				return $groupName;
-			}
-		}
-
-		return false;
-	}
-
-	/**
-	 * This function fetches all groups a user belongs to. It does not check
-	 * if the user exists at all.
-	 *
-	 * This function includes groups based on dynamic group membership.
-	 *
-	 * @param string $uid Name of the user
-	 * @return array with group names
-	 * @throws Exception
-	 * @throws ServerNotAvailableException
-	 */
-	public function getUserGroups($uid) {
-		if (!$this->enabled) {
-			return [];
-		}
-		$cacheKey = 'getUserGroups' . $uid;
-		$userGroups = $this->access->connection->getFromCache($cacheKey);
-		if (!is_null($userGroups)) {
-			return $userGroups;
-		}
-		$userDN = $this->access->username2dn($uid);
-		if (!$userDN) {
-			$this->access->connection->writeToCache($cacheKey, []);
-			return [];
-		}
-
-		$groups = [];
-		$primaryGroup = $this->getUserPrimaryGroup($userDN);
-		$gidGroupName = $this->getUserGroupByGid($userDN);
-
-		$dynamicGroupMemberURL = strtolower($this->access->connection->ldapDynamicGroupMemberURL);
-
-		if (!empty($dynamicGroupMemberURL)) {
-			// look through dynamic groups to add them to the result array if needed
-			$groupsToMatch = $this->access->fetchListOfGroups(
-				$this->access->connection->ldapGroupFilter, ['dn', $dynamicGroupMemberURL]);
-			foreach ($groupsToMatch as $dynamicGroup) {
-				if (!array_key_exists($dynamicGroupMemberURL, $dynamicGroup)) {
-					continue;
-				}
-				$pos = strpos($dynamicGroup[$dynamicGroupMemberURL][0], '(');
-				if ($pos !== false) {
-					$memberUrlFilter = substr($dynamicGroup[$dynamicGroupMemberURL][0], $pos);
-					// apply filter via ldap search to see if this user is in this
-					// dynamic group
-					$userMatch = $this->access->readAttribute(
-						$userDN,
-						$this->access->connection->ldapUserDisplayName,
-						$memberUrlFilter
-					);
-					if ($userMatch !== false) {
-						// match found so this user is in this group
-						$groupName = $this->access->dn2groupname($dynamicGroup['dn'][0]);
-						if (is_string($groupName)) {
-							// be sure to never return false if the dn could not be
-							// resolved to a name, for whatever reason.
-							$groups[] = $groupName;
-						}
-					}
-				} else {
-					$this->logger->debug('No search filter found on member url of group {dn}',
-						[
-							'app' => 'user_ldap',
-							'dn' => $dynamicGroup,
-						]
-					);
-				}
-			}
-		}
-
-		// if possible, read out membership via memberOf. It's far faster than
-		// performing a search, which still is a fallback later.
-		// memberof doesn't support memberuid, so skip it here.
-		if ((int)$this->access->connection->hasMemberOfFilterSupport === 1
-			&& (int)$this->access->connection->useMemberOfToDetectMembership === 1
-			&& $this->ldapGroupMemberAssocAttr !== 'memberuid'
-			&& $this->ldapGroupMemberAssocAttr !== 'zimbramailforwardingaddress') {
-			$groupDNs = $this->_getGroupDNsFromMemberOf($userDN);
-			if (is_array($groupDNs)) {
-				foreach ($groupDNs as $dn) {
-					$groupName = $this->access->dn2groupname($dn);
-					if (is_string($groupName)) {
-						// be sure to never return false if the dn could not be
-						// resolved to a name, for whatever reason.
-						$groups[] = $groupName;
-					}
-				}
-			}
-
-			if ($primaryGroup !== false) {
-				$groups[] = $primaryGroup;
-			}
-			if ($gidGroupName !== false) {
-				$groups[] = $gidGroupName;
-			}
-			$this->access->connection->writeToCache($cacheKey, $groups);
-			return $groups;
-		}
-
-		//uniqueMember takes DN, memberuid the uid, so we need to distinguish
-		switch ($this->ldapGroupMemberAssocAttr) {
-			case 'uniquemember':
-			case 'member':
-				$uid = $userDN;
-				break;
-
-			case 'memberuid':
-			case 'zimbramailforwardingaddress':
-				$result = $this->access->readAttribute($userDN, 'uid');
-				if ($result === false) {
-					$this->logger->debug('No uid attribute found for DN {dn} on {host}',
-						[
-							'app' => 'user_ldap',
-							'dn' => $userDN,
-							'host' => $this->access->connection->ldapHost,
-						]
-					);
-					$uid = false;
-				} else {
-					$uid = $result[0];
-				}
-				break;
-
-			default:
-				// just in case
-				$uid = $userDN;
-				break;
-		}
-
-		if ($uid !== false) {
-			if (isset($this->cachedGroupsByMember[$uid])) {
-				$groups = array_merge($groups, $this->cachedGroupsByMember[$uid]);
-			} else {
-				$groupsByMember = array_values($this->getGroupsByMember($uid));
-				$groupsByMember = $this->access->nextcloudGroupNames($groupsByMember);
-				$this->cachedGroupsByMember[$uid] = $groupsByMember;
-				$groups = array_merge($groups, $groupsByMember);
-			}
-		}
-
-		if ($primaryGroup !== false) {
-			$groups[] = $primaryGroup;
-		}
-		if ($gidGroupName !== false) {
-			$groups[] = $gidGroupName;
-		}
-
-		$groups = array_unique($groups, SORT_LOCALE_STRING);
-		$this->access->connection->writeToCache($cacheKey, $groups);
-
-		return $groups;
-	}
-
-	/**
-	 * @throws ServerNotAvailableException
-	 */
-	private function getGroupsByMember(string $dn, array &$seen = null): array {
-		if ($seen === null) {
-			$seen = [];
-		}
-		if (array_key_exists($dn, $seen)) {
-			// avoid loops
-			return [];
-		}
-		$allGroups = [];
-		$seen[$dn] = true;
-		$filter = $this->access->connection->ldapGroupMemberAssocAttr . '=' . $dn;
-
-		if ($this->ldapGroupMemberAssocAttr === 'zimbramailforwardingaddress') {
-			//in this case the member entries are email addresses
-			$filter .= '@*';
-		}
-
-		$nesting = (int)$this->access->connection->ldapNestedGroups;
-		if ($nesting === 0) {
-			$filter = $this->access->combineFilterWithAnd([$filter, $this->access->connection->ldapGroupFilter]);
-		}
-
-		$groups = $this->access->fetchListOfGroups($filter,
-			[strtolower($this->access->connection->ldapGroupMemberAssocAttr), $this->access->connection->ldapGroupDisplayName, 'dn']);
-		if (is_array($groups)) {
-			$fetcher = function ($dn, &$seen) {
-				if (is_array($dn) && isset($dn['dn'][0])) {
-					$dn = $dn['dn'][0];
-				}
-				return $this->getGroupsByMember($dn, $seen);
-			};
-
-			if (empty($dn)) {
-				$dn = "";
-			}
-
-			$allGroups = $this->walkNestedGroups($dn, $fetcher, $groups);
-		}
-		$visibleGroups = $this->filterValidGroups($allGroups);
-		return array_intersect_key($allGroups, $visibleGroups);
-	}
-
-	/**
-	 * get a list of all users in a group
-	 *
-	 * @param string $gid
-	 * @param string $search
-	 * @param int $limit
-	 * @param int $offset
-	 * @return array with user ids
-	 * @throws Exception
-	 * @throws ServerNotAvailableException
-	 */
-	public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
-		if (!$this->enabled) {
-			return [];
-		}
-		if (!$this->groupExists($gid)) {
-			return [];
-		}
-		$search = $this->access->escapeFilterPart($search, true);
-		$cacheKey = 'usersInGroup-' . $gid . '-' . $search . '-' . $limit . '-' . $offset;
-		// check for cache of the exact query
-		$groupUsers = $this->access->connection->getFromCache($cacheKey);
-		if (!is_null($groupUsers)) {
-			return $groupUsers;
-		}
-
-		if ($limit === -1) {
-			$limit = null;
-		}
-		// check for cache of the query without limit and offset
-		$groupUsers = $this->access->connection->getFromCache('usersInGroup-' . $gid . '-' . $search);
-		if (!is_null($groupUsers)) {
-			$groupUsers = array_slice($groupUsers, $offset, $limit);
-			$this->access->connection->writeToCache($cacheKey, $groupUsers);
-			return $groupUsers;
-		}
-
-		$groupDN = $this->access->groupname2dn($gid);
-		if (!$groupDN) {
-			// group couldn't be found, return empty resultset
-			$this->access->connection->writeToCache($cacheKey, []);
-			return [];
-		}
-
-		$primaryUsers = $this->getUsersInPrimaryGroup($groupDN, $search, $limit, $offset);
-		$posixGroupUsers = $this->getUsersInGidNumber($groupDN, $search, $limit, $offset);
-		$members = $this->_groupMembers($groupDN);
-		if (!$members && empty($posixGroupUsers) && empty($primaryUsers)) {
-			//in case users could not be retrieved, return empty result set
-			$this->access->connection->writeToCache($cacheKey, []);
-			return [];
-		}
-
-		$groupUsers = [];
-		$attrs = $this->access->userManager->getAttributes(true);
-		foreach ($members as $member) {
-			switch ($this->ldapGroupMemberAssocAttr) {
-				case 'zimbramailforwardingaddress':
-					//we get email addresses and need to convert them to uids
-					$parts = explode('@', $member);
-					$member = $parts[0];
-					//no break needed because we just needed to remove the email part and now we have uids
-				case 'memberuid':
-					//we got uids, need to get their DNs to 'translate' them to user names
-					$filter = $this->access->combineFilterWithAnd([
-						str_replace('%uid', trim($member), $this->access->connection->ldapLoginFilter),
-						$this->access->combineFilterWithAnd([
-							$this->access->getFilterPartForUserSearch($search),
-							$this->access->connection->ldapUserFilter
-						])
-					]);
-					$ldap_users = $this->access->fetchListOfUsers($filter, $attrs, 1);
-					if (empty($ldap_users)) {
-						break;
-					}
-					$groupUsers[] = $this->access->dn2username($ldap_users[0]['dn'][0]);
-					break;
-				default:
-					//we got DNs, check if we need to filter by search or we can give back all of them
-					$uid = $this->access->dn2username($member);
-					if (!$uid) {
-						break;
-					}
-
-					$cacheKey = 'userExistsOnLDAP' . $uid;
-					$userExists = $this->access->connection->getFromCache($cacheKey);
-					if ($userExists === false) {
-						break;
-					}
-					if ($userExists === null || $search !== '') {
-						if (!$this->access->readAttribute($member,
-							$this->access->connection->ldapUserDisplayName,
-							$this->access->combineFilterWithAnd([
-								$this->access->getFilterPartForUserSearch($search),
-								$this->access->connection->ldapUserFilter
-							]))) {
-							if ($search === '') {
-								$this->access->connection->writeToCache($cacheKey, false);
-							}
-							break;
-						}
-						$this->access->connection->writeToCache($cacheKey, true);
-					}
-					$groupUsers[] = $uid;
-					break;
-			}
-		}
-
-		$groupUsers = array_unique(array_merge($groupUsers, $primaryUsers, $posixGroupUsers));
-		natsort($groupUsers);
-		$this->access->connection->writeToCache('usersInGroup-' . $gid . '-' . $search, $groupUsers);
-		$groupUsers = array_slice($groupUsers, $offset, $limit);
-
-		$this->access->connection->writeToCache($cacheKey, $groupUsers);
-
-		return $groupUsers;
-	}
-
-	/**
-	 * returns the number of users in a group, who match the search term
-	 *
-	 * @param string $gid the internal group name
-	 * @param string $search optional, a search string
-	 * @return int|bool
-	 * @throws Exception
-	 * @throws ServerNotAvailableException
-	 */
-	public function countUsersInGroup($gid, $search = '') {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::COUNT_USERS)) {
-			return $this->groupPluginManager->countUsersInGroup($gid, $search);
-		}
-
-		$cacheKey = 'countUsersInGroup-' . $gid . '-' . $search;
-		if (!$this->enabled || !$this->groupExists($gid)) {
-			return false;
-		}
-		$groupUsers = $this->access->connection->getFromCache($cacheKey);
-		if (!is_null($groupUsers)) {
-			return $groupUsers;
-		}
-
-		$groupDN = $this->access->groupname2dn($gid);
-		if (!$groupDN) {
-			// group couldn't be found, return empty result set
-			$this->access->connection->writeToCache($cacheKey, false);
-			return false;
-		}
-
-		$members = $this->_groupMembers($groupDN);
-		$primaryUserCount = $this->countUsersInPrimaryGroup($groupDN, '');
-		if (!$members && $primaryUserCount === 0) {
-			//in case users could not be retrieved, return empty result set
-			$this->access->connection->writeToCache($cacheKey, false);
-			return false;
-		}
-
-		if ($search === '') {
-			$groupUsers = count($members) + $primaryUserCount;
-			$this->access->connection->writeToCache($cacheKey, $groupUsers);
-			return $groupUsers;
-		}
-		$search = $this->access->escapeFilterPart($search, true);
-		$isMemberUid =
-			($this->ldapGroupMemberAssocAttr === 'memberuid' ||
-				$this->ldapGroupMemberAssocAttr === 'zimbramailforwardingaddress');
-
-		//we need to apply the search filter
-		//alternatives that need to be checked:
-		//a) get all users by search filter and array_intersect them
-		//b) a, but only when less than 1k 10k ?k users like it is
-		//c) put all DNs|uids in a LDAP filter, combine with the search string
-		//   and let it count.
-		//For now this is not important, because the only use of this method
-		//does not supply a search string
-		$groupUsers = [];
-		foreach ($members as $member) {
-			if ($isMemberUid) {
-				if ($this->ldapGroupMemberAssocAttr === 'zimbramailforwardingaddress') {
-					//we get email addresses and need to convert them to uids
-					$parts = explode('@', $member);
-					$member = $parts[0];
-				}
-				//we got uids, need to get their DNs to 'translate' them to user names
-				$filter = $this->access->combineFilterWithAnd([
-					str_replace('%uid', $member, $this->access->connection->ldapLoginFilter),
-					$this->access->getFilterPartForUserSearch($search)
-				]);
-				$ldap_users = $this->access->fetchListOfUsers($filter, ['dn'], 1);
-				if (count($ldap_users) < 1) {
-					continue;
-				}
-				$groupUsers[] = $this->access->dn2username($ldap_users[0]);
-			} else {
-				//we need to apply the search filter now
-				if (!$this->access->readAttribute($member,
-					$this->access->connection->ldapUserDisplayName,
-					$this->access->getFilterPartForUserSearch($search))) {
-					continue;
-				}
-				// dn2username will also check if the users belong to the allowed base
-				if ($ncGroupId = $this->access->dn2username($member)) {
-					$groupUsers[] = $ncGroupId;
-				}
-			}
-		}
-
-		//and get users that have the group as primary
-		$primaryUsers = $this->countUsersInPrimaryGroup($groupDN, $search);
-
-		return count($groupUsers) + $primaryUsers;
-	}
-
-	/**
-	 * get a list of all groups using a paged search
-	 *
-	 * @param string $search
-	 * @param int $limit
-	 * @param int $offset
-	 * @return array with group names
-	 *
-	 * Returns a list with all groups
-	 * Uses a paged search if available to override a
-	 * server side search limit.
-	 * (active directory has a limit of 1000 by default)
-	 * @throws Exception
-	 */
-	public function getGroups($search = '', $limit = -1, $offset = 0) {
-		if (!$this->enabled) {
-			return [];
-		}
-		$cacheKey = 'getGroups-' . $search . '-' . $limit . '-' . $offset;
-
-		//Check cache before driving unnecessary searches
-		$ldap_groups = $this->access->connection->getFromCache($cacheKey);
-		if (!is_null($ldap_groups)) {
-			return $ldap_groups;
-		}
-
-		// if we'd pass -1 to LDAP search, we'd end up in a Protocol
-		// error. With a limit of 0, we get 0 results. So we pass null.
-		if ($limit <= 0) {
-			$limit = null;
-		}
-		$filter = $this->access->combineFilterWithAnd([
-			$this->access->connection->ldapGroupFilter,
-			$this->access->getFilterPartForGroupSearch($search)
-		]);
-		$ldap_groups = $this->access->fetchListOfGroups($filter,
-			[$this->access->connection->ldapGroupDisplayName, 'dn'],
-			$limit,
-			$offset);
-		$ldap_groups = $this->access->nextcloudGroupNames($ldap_groups);
-
-		$this->access->connection->writeToCache($cacheKey, $ldap_groups);
-		return $ldap_groups;
-	}
-
-	/**
-	 * check if a group exists
-	 *
-	 * @param string $gid
-	 * @return bool
-	 * @throws ServerNotAvailableException
-	 */
-	public function groupExists($gid) {
-		$groupExists = $this->access->connection->getFromCache('groupExists' . $gid);
-		if (!is_null($groupExists)) {
-			return (bool)$groupExists;
-		}
-
-		//getting dn, if false the group does not exist. If dn, it may be mapped
-		//only, requires more checking.
-		$dn = $this->access->groupname2dn($gid);
-		if (!$dn) {
-			$this->access->connection->writeToCache('groupExists' . $gid, false);
-			return false;
-		}
-
-		if (!$this->access->isDNPartOfBase($dn, $this->access->connection->ldapBaseGroups)) {
-			$this->access->connection->writeToCache('groupExists' . $gid, false);
-			return false;
-		}
-
-		//if group really still exists, we will be able to read its objectClass
-		if (!is_array($this->access->readAttribute($dn, '', $this->access->connection->ldapGroupFilter))) {
-			$this->access->connection->writeToCache('groupExists' . $gid, false);
-			return false;
-		}
-
-		$this->access->connection->writeToCache('groupExists' . $gid, true);
-		return true;
-	}
-
-	/**
-	 * @throws ServerNotAvailableException
-	 * @throws Exception
-	 */
-	protected function filterValidGroups(array $listOfGroups): array {
-		$validGroupDNs = [];
-		foreach ($listOfGroups as $key => $item) {
-			$dn = is_string($item) ? $item : $item['dn'][0];
-			$gid = $this->access->dn2groupname($dn);
-			if (!$gid) {
-				continue;
-			}
-			if ($this->groupExists($gid)) {
-				$validGroupDNs[$key] = $item;
-			}
-		}
-		return $validGroupDNs;
-	}
-
-	/**
-	 * Check if backend implements actions
-	 *
-	 * @param int $actions bitwise-or'ed actions
-	 * @return boolean
-	 *
-	 * Returns the supported actions as int to be
-	 * compared with GroupInterface::CREATE_GROUP etc.
-	 */
-	public function implementsActions($actions) {
-		return (bool)((GroupInterface::COUNT_USERS |
-				$this->groupPluginManager->getImplementedActions()) & $actions);
-	}
-
-	/**
-	 * Return access for LDAP interaction.
-	 *
-	 * @return Access instance of Access for LDAP interaction
-	 */
-	public function getLDAPAccess($gid) {
-		return $this->access;
-	}
-
-	/**
-	 * create a group
-	 *
-	 * @param string $gid
-	 * @return bool
-	 * @throws Exception
-	 * @throws ServerNotAvailableException
-	 */
-	public function createGroup($gid) {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::CREATE_GROUP)) {
-			if ($dn = $this->groupPluginManager->createGroup($gid)) {
-				//updates group mapping
-				$uuid = $this->access->getUUID($dn, false);
-				if (is_string($uuid)) {
-					$this->access->mapAndAnnounceIfApplicable(
-						$this->access->getGroupMapper(),
-						$dn,
-						$gid,
-						$uuid,
-						false
-					);
-					$this->access->cacheGroupExists($gid);
-				}
-			}
-			return $dn != null;
-		}
-		throw new Exception('Could not create group in LDAP backend.');
-	}
-
-	/**
-	 * delete a group
-	 *
-	 * @param string $gid gid of the group to delete
-	 * @return bool
-	 * @throws Exception
-	 */
-	public function deleteGroup($gid) {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::DELETE_GROUP)) {
-			if ($ret = $this->groupPluginManager->deleteGroup($gid)) {
-				#delete group in nextcloud internal db
-				$this->access->getGroupMapper()->unmap($gid);
-				$this->access->connection->writeToCache("groupExists" . $gid, false);
-			}
-			return $ret;
-		}
-		throw new Exception('Could not delete group in LDAP backend.');
-	}
-
-	/**
-	 * Add a user to a group
-	 *
-	 * @param string $uid Name of the user to add to group
-	 * @param string $gid Name of the group in which add the user
-	 * @return bool
-	 * @throws Exception
-	 */
-	public function addToGroup($uid, $gid) {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::ADD_TO_GROUP)) {
-			if ($ret = $this->groupPluginManager->addToGroup($uid, $gid)) {
-				$this->access->connection->clearCache();
-				unset($this->cachedGroupMembers[$gid]);
-			}
-			return $ret;
-		}
-		throw new Exception('Could not add user to group in LDAP backend.');
-	}
-
-	/**
-	 * Removes a user from a group
-	 *
-	 * @param string $uid Name of the user to remove from group
-	 * @param string $gid Name of the group from which remove the user
-	 * @return bool
-	 * @throws Exception
-	 */
-	public function removeFromGroup($uid, $gid) {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::REMOVE_FROM_GROUP)) {
-			if ($ret = $this->groupPluginManager->removeFromGroup($uid, $gid)) {
-				$this->access->connection->clearCache();
-				unset($this->cachedGroupMembers[$gid]);
-			}
-			return $ret;
-		}
-		throw new Exception('Could not remove user from group in LDAP backend.');
-	}
-
-	/**
-	 * Gets group details
-	 *
-	 * @param string $gid Name of the group
-	 * @return array|false
-	 * @throws Exception
-	 */
-	public function getGroupDetails($gid) {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::GROUP_DETAILS)) {
-			return $this->groupPluginManager->getGroupDetails($gid);
-		}
-		throw new Exception('Could not get group details in LDAP backend.');
-	}
-
-	/**
-	 * Return LDAP connection resource from a cloned connection.
-	 * The cloned connection needs to be closed manually.
-	 * of the current access.
-	 *
-	 * @param string $gid
-	 * @return resource of the LDAP connection
-	 * @throws ServerNotAvailableException
-	 */
-	public function getNewLDAPConnection($gid) {
-		$connection = clone $this->access->getConnection();
-		return $connection->getConnectionResource();
-	}
-
-	/**
-	 * @throws ServerNotAvailableException
-	 */
-	public function getDisplayName(string $gid): string {
-		if ($this->groupPluginManager instanceof IGetDisplayNameBackend) {
-			return $this->groupPluginManager->getDisplayName($gid);
-		}
-
-		$cacheKey = 'group_getDisplayName' . $gid;
-		if (!is_null($displayName = $this->access->connection->getFromCache($cacheKey))) {
-			return $displayName;
-		}
-
-		$displayName = $this->access->readAttribute(
-			$this->access->groupname2dn($gid),
-			$this->access->connection->ldapGroupDisplayName);
-
-		if ($displayName && (count($displayName) > 0)) {
-			$displayName = $displayName[0];
-			$this->access->connection->writeToCache($cacheKey, $displayName);
-			return $displayName;
-		}
-
-		return '';
-	}
+    protected $enabled = false;
+
+    /** @var string[] $cachedGroupMembers array of users with gid as key */
+    protected $cachedGroupMembers;
+    /** @var string[] $cachedGroupsByMember array of groups with uid as key */
+    protected $cachedGroupsByMember;
+    /** @var string[] $cachedNestedGroups array of groups with gid (DN) as key */
+    protected $cachedNestedGroups;
+    /** @var GroupPluginManager */
+    protected $groupPluginManager;
+    /** @var ILogger */
+    protected $logger;
+
+    /**
+     * @var string $ldapGroupMemberAssocAttr contains the LDAP setting (in lower case) with the same name
+     */
+    protected $ldapGroupMemberAssocAttr;
+
+    public function __construct(Access $access, GroupPluginManager $groupPluginManager) {
+        parent::__construct($access);
+        $filter = $this->access->connection->ldapGroupFilter;
+        $gAssoc = $this->access->connection->ldapGroupMemberAssocAttr;
+        if (!empty($filter) && !empty($gAssoc)) {
+            $this->enabled = true;
+        }
+
+        $this->cachedGroupMembers = new CappedMemoryCache();
+        $this->cachedGroupsByMember = new CappedMemoryCache();
+        $this->cachedNestedGroups = new CappedMemoryCache();
+        $this->groupPluginManager = $groupPluginManager;
+        $this->logger = OC::$server->getLogger();
+        $this->ldapGroupMemberAssocAttr = strtolower($gAssoc);
+    }
+
+    /**
+     * is user in group?
+     *
+     * @param string $uid uid of the user
+     * @param string $gid gid of the group
+     * @return bool
+     * @throws Exception
+     * @throws ServerNotAvailableException
+     */
+    public function inGroup($uid, $gid) {
+        if (!$this->enabled) {
+            return false;
+        }
+        $cacheKey = 'inGroup' . $uid . ':' . $gid;
+        $inGroup = $this->access->connection->getFromCache($cacheKey);
+        if (!is_null($inGroup)) {
+            return (bool)$inGroup;
+        }
+
+        $userDN = $this->access->username2dn($uid);
+
+        if (isset($this->cachedGroupMembers[$gid])) {
+            return in_array($userDN, $this->cachedGroupMembers[$gid]);
+        }
+
+        $cacheKeyMembers = 'inGroup-members:' . $gid;
+        $members = $this->access->connection->getFromCache($cacheKeyMembers);
+        if (!is_null($members)) {
+            $this->cachedGroupMembers[$gid] = $members;
+            $isInGroup = in_array($userDN, $members, true);
+            $this->access->connection->writeToCache($cacheKey, $isInGroup);
+            return $isInGroup;
+        }
+
+        $groupDN = $this->access->groupname2dn($gid);
+        // just in case
+        if (!$groupDN || !$userDN) {
+            $this->access->connection->writeToCache($cacheKey, false);
+            return false;
+        }
+
+        //check primary group first
+        if ($gid === $this->getUserPrimaryGroup($userDN)) {
+            $this->access->connection->writeToCache($cacheKey, true);
+            return true;
+        }
+
+        //usually, LDAP attributes are said to be case insensitive. But there are exceptions of course.
+        $members = $this->_groupMembers($groupDN);
+        if (!is_array($members) || count($members) === 0) {
+            $this->access->connection->writeToCache($cacheKey, false);
+            return false;
+        }
+
+        //extra work if we don't get back user DNs
+        switch ($this->ldapGroupMemberAssocAttr) {
+            case 'memberuid':
+            case 'zimbramailforwardingaddress':
+                $requestAttributes = $this->access->userManager->getAttributes(true);
+                $dns = [];
+                $filterParts = [];
+                $bytes = 0;
+                foreach ($members as $mid) {
+                    if ($this->ldapGroupMemberAssocAttr === 'zimbramailforwardingaddress') {
+                        $parts = explode('@', $mid); //making sure we get only the uid
+                        $mid = $parts[0];
+                    }
+                    $filter = str_replace('%uid', $mid, $this->access->connection->ldapLoginFilter);
+                    $filterParts[] = $filter;
+                    $bytes += strlen($filter);
+                    if ($bytes >= 9000000) {
+                        // AD has a default input buffer of 10 MB, we do not want
+                        // to take even the chance to exceed it
+                        $filter = $this->access->combineFilterWithOr($filterParts);
+                        $users = $this->access->fetchListOfUsers($filter, $requestAttributes, count($filterParts));
+                        $bytes = 0;
+                        $filterParts = [];
+                        $dns = array_merge($dns, $users);
+                    }
+                }
+                if (count($filterParts) > 0) {
+                    $filter = $this->access->combineFilterWithOr($filterParts);
+                    $users = $this->access->fetchListOfUsers($filter, $requestAttributes, count($filterParts));
+                    $dns = array_merge($dns, $users);
+                }
+                $members = $dns;
+                break;
+        }
+
+        $isInGroup = in_array($userDN, $members);
+        $this->access->connection->writeToCache($cacheKey, $isInGroup);
+        $this->access->connection->writeToCache($cacheKeyMembers, $members);
+        $this->cachedGroupMembers[$gid] = $members;
+
+        return $isInGroup;
+    }
+
+    /**
+     * For a group that has user membership defined by an LDAP search url
+     * attribute returns the users that match the search url otherwise returns
+     * an empty array.
+     *
+     * @throws ServerNotAvailableException
+     */
+    public function getDynamicGroupMembers(string $dnGroup): array {
+        $dynamicGroupMemberURL = strtolower($this->access->connection->ldapDynamicGroupMemberURL);
+
+        if (empty($dynamicGroupMemberURL)) {
+            return [];
+        }
+
+        $dynamicMembers = [];
+        $memberURLs = $this->access->readAttribute(
+            $dnGroup,
+            $dynamicGroupMemberURL,
+            $this->access->connection->ldapGroupFilter
+        );
+        if ($memberURLs !== false) {
+            // this group has the 'memberURL' attribute so this is a dynamic group
+            // example 1: ldap:///cn=users,cn=accounts,dc=dcsubbase,dc=dcbase??one?(o=HeadOffice)
+            // example 2: ldap:///cn=users,cn=accounts,dc=dcsubbase,dc=dcbase??one?(&(o=HeadOffice)(uidNumber>=500))
+            $pos = strpos($memberURLs[0], '(');
+            if ($pos !== false) {
+                $memberUrlFilter = substr($memberURLs[0], $pos);
+                $foundMembers = $this->access->searchUsers($memberUrlFilter, 'dn');
+                $dynamicMembers = [];
+                foreach ($foundMembers as $value) {
+                    $dynamicMembers[$value['dn'][0]] = 1;
+                }
+            } else {
+                $this->logger->debug('No search filter found on member url of group {dn}',
+                    [
+                        'app' => 'user_ldap',
+                        'dn' => $dnGroup,
+                    ]
+                );
+            }
+        }
+        return $dynamicMembers;
+    }
+
+    /**
+     * @throws ServerNotAvailableException
+     */
+    private function _groupMembers(string $dnGroup, ?array &$seen = null): array {
+        if ($seen === null) {
+            $seen = [];
+        }
+        $allMembers = [];
+        if (array_key_exists($dnGroup, $seen)) {
+            return [];
+        }
+        // used extensively in cron job, caching makes sense for nested groups
+        $cacheKey = '_groupMembers' . $dnGroup;
+        $groupMembers = $this->access->connection->getFromCache($cacheKey);
+        if ($groupMembers !== null) {
+            return $groupMembers;
+        }
+
+        if ($this->access->connection->ldapNestedGroups
+            && $this->access->connection->useMemberOfToDetectMembership
+            && $this->access->connection->hasMemberOfFilterSupport
+            && $this->access->connection->ldapMatchingRuleInChainState !== Configuration::LDAP_SERVER_FEATURE_UNAVAILABLE
+        ) {
+            $attemptedLdapMatchingRuleInChain = true;
+            // compatibility hack with servers supporting :1.2.840.113556.1.4.1941:, and others)
+            $filter = $this->access->combineFilterWithAnd([
+                $this->access->connection->ldapUserFilter,
+                $this->access->connection->ldapUserDisplayName . '=*',
+                'memberof:1.2.840.113556.1.4.1941:=' . $dnGroup
+            ]);
+            $memberRecords = $this->access->fetchListOfUsers(
+                $filter,
+                $this->access->userManager->getAttributes(true)
+            );
+            $result = array_reduce($memberRecords, function ($carry, $record) {
+                $carry[] = $record['dn'][0];
+                return $carry;
+            }, []);
+            if ($this->access->connection->ldapMatchingRuleInChainState === Configuration::LDAP_SERVER_FEATURE_AVAILABLE) {
+                return $result;
+            } elseif (!empty($memberRecords)) {
+                $this->access->connection->ldapMatchingRuleInChainState = Configuration::LDAP_SERVER_FEATURE_AVAILABLE;
+                $this->access->connection->saveConfiguration();
+                return $result;
+            }
+            // when feature availability is unknown, and the result is empty, continue and test with original approach
+        }
+
+        $seen[$dnGroup] = 1;
+        $members = $this->access->readAttribute($dnGroup, $this->access->connection->ldapGroupMemberAssocAttr);
+        if (is_array($members)) {
+            $fetcher = function ($memberDN, &$seen) {
+                return $this->_groupMembers($memberDN, $seen);
+            };
+            $allMembers = $this->walkNestedGroups($dnGroup, $fetcher, $members);
+        }
+
+        $allMembers += $this->getDynamicGroupMembers($dnGroup);
+
+        $this->access->connection->writeToCache($cacheKey, $allMembers);
+        if (isset($attemptedLdapMatchingRuleInChain)
+            && $this->access->connection->ldapMatchingRuleInChainState === Configuration::LDAP_SERVER_FEATURE_UNKNOWN
+            && !empty($allMembers)
+        ) {
+            $this->access->connection->ldapMatchingRuleInChainState = Configuration::LDAP_SERVER_FEATURE_UNAVAILABLE;
+            $this->access->connection->saveConfiguration();
+        }
+        return $allMembers;
+    }
+
+    /**
+     * @throws ServerNotAvailableException
+     */
+    private function _getGroupDNsFromMemberOf(string $dn): array {
+        $groups = $this->access->readAttribute($dn, 'memberOf');
+        if (!is_array($groups)) {
+            return [];
+        }
+
+        $fetcher = function ($groupDN) {
+            if (isset($this->cachedNestedGroups[$groupDN])) {
+                $nestedGroups = $this->cachedNestedGroups[$groupDN];
+            } else {
+                $nestedGroups = $this->access->readAttribute($groupDN, 'memberOf');
+                if (!is_array($nestedGroups)) {
+                    $nestedGroups = [];
+                }
+                $this->cachedNestedGroups[$groupDN] = $nestedGroups;
+            }
+            return $nestedGroups;
+        };
+
+        $groups = $this->walkNestedGroups($dn, $fetcher, $groups);
+        return $this->filterValidGroups($groups);
+    }
+
+    private function walkNestedGroups(string $dn, Closure $fetcher, array $list): array {
+        $nesting = (int)$this->access->connection->ldapNestedGroups;
+        // depending on the input, we either have a list of DNs or a list of LDAP records
+        // also, the output expects either DNs or records. Testing the first element should suffice.
+        $recordMode = is_array($list) && isset($list[0]) && is_array($list[0]) && isset($list[0]['dn'][0]);
+
+        if ($nesting !== 1) {
+            if ($recordMode) {
+                // the keys are numeric, but should hold the DN
+                return array_reduce($list, function ($transformed, $record) use ($dn) {
+                    if ($record['dn'][0] != $dn) {
+                        $transformed[$record['dn'][0]] = $record;
+                    }
+                    return $transformed;
+                }, []);
+            }
+            return $list;
+        }
+
+        $seen = [];
+        while ($record = array_shift($list)) {
+            $recordDN = $recordMode ? $record['dn'][0] : $record;
+            if ($recordDN === $dn || array_key_exists($recordDN, $seen)) {
+                // Prevent loops
+                continue;
+            }
+            $fetched = $fetcher($record, $seen);
+            $list = array_merge($list, $fetched);
+            $seen[$recordDN] = $record;
+        }
+
+        return $recordMode ? $seen : array_keys($seen);
+    }
+
+    /**
+     * translates a gidNumber into an ownCloud internal name
+     *
+     * @return string|bool
+     * @throws Exception
+     * @throws ServerNotAvailableException
+     */
+    public function gidNumber2Name(string $gid, string $dn) {
+        $cacheKey = 'gidNumberToName' . $gid;
+        $groupName = $this->access->connection->getFromCache($cacheKey);
+        if (!is_null($groupName) && isset($groupName)) {
+            return $groupName;
+        }
+
+        //we need to get the DN from LDAP
+        $filter = $this->access->combineFilterWithAnd([
+            $this->access->connection->ldapGroupFilter,
+            'objectClass=posixGroup',
+            $this->access->connection->ldapGidNumber . '=' . $gid
+        ]);
+        return $this->getNameOfGroup($filter, $cacheKey) ?? false;
+    }
+
+    /**
+     * @throws ServerNotAvailableException
+     * @throws Exception
+     */
+    private function getNameOfGroup(string $filter, string $cacheKey) {
+        $result = $this->access->searchGroups($filter, ['dn'], 1);
+        if (empty($result)) {
+            return null;
+        }
+        $dn = $result[0]['dn'][0];
+
+        //and now the group name
+        //NOTE once we have separate Nextcloud group IDs and group names we can
+        //directly read the display name attribute instead of the DN
+        $name = $this->access->dn2groupname($dn);
+
+        $this->access->connection->writeToCache($cacheKey, $name);
+
+        return $name;
+    }
+
+    /**
+     * returns the entry's gidNumber
+     *
+     * @return string|bool
+     * @throws ServerNotAvailableException
+     */
+    private function getEntryGidNumber(string $dn, string $attribute) {
+        $value = $this->access->readAttribute($dn, $attribute);
+        if (is_array($value) && !empty($value)) {
+            return $value[0];
+        }
+        return false;
+    }
+
+    /**
+     * @return string|bool
+     * @throws ServerNotAvailableException
+     */
+    public function getGroupGidNumber(string $dn) {
+        return $this->getEntryGidNumber($dn, 'gidNumber');
+    }
+
+    /**
+     * returns the user's gidNumber
+     *
+     * @return string|bool
+     * @throws ServerNotAvailableException
+     */
+    public function getUserGidNumber(string $dn) {
+        $gidNumber = false;
+        if ($this->access->connection->hasGidNumber) {
+            $gidNumber = $this->getEntryGidNumber($dn, $this->access->connection->ldapGidNumber);
+            if ($gidNumber === false) {
+                $this->access->connection->hasGidNumber = false;
+            }
+        }
+        return $gidNumber;
+    }
+
+    /**
+     * @throws ServerNotAvailableException
+     * @throws Exception
+     */
+    private function prepareFilterForUsersHasGidNumber(string $groupDN, string $search = ''): string {
+        $groupID = $this->getGroupGidNumber($groupDN);
+        if ($groupID === false) {
+            throw new Exception('Not a valid group');
+        }
+
+        $filterParts = [];
+        $filterParts[] = $this->access->getFilterForUserCount();
+        if ($search !== '') {
+            $filterParts[] = $this->access->getFilterPartForUserSearch($search);
+        }
+        $filterParts[] = $this->access->connection->ldapGidNumber . '=' . $groupID;
+
+        return $this->access->combineFilterWithAnd($filterParts);
+    }
+
+    /**
+     * returns a list of users that have the given group as gid number
+     *
+     * @throws ServerNotAvailableException
+     */
+    public function getUsersInGidNumber(
+        string $groupDN,
+        string $search = '',
+        ?int $limit = -1,
+        ?int $offset = 0
+    ): array {
+        try {
+            $filter = $this->prepareFilterForUsersHasGidNumber($groupDN, $search);
+            $users = $this->access->fetchListOfUsers(
+                $filter,
+                [$this->access->connection->ldapUserDisplayName, 'dn'],
+                $limit,
+                $offset
+            );
+            return $this->access->nextcloudUserNames($users);
+        } catch (ServerNotAvailableException $e) {
+            throw $e;
+        } catch (Exception $e) {
+            return [];
+        }
+    }
+
+    /**
+     * @throws ServerNotAvailableException
+     * @return bool
+     */
+    public function getUserGroupByGid(string $dn) {
+        $groupID = $this->getUserGidNumber($dn);
+        if ($groupID !== false) {
+            $groupName = $this->gidNumber2Name($groupID, $dn);
+            if ($groupName !== false) {
+                return $groupName;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * translates a primary group ID into an Nextcloud internal name
+     *
+     * @return string|bool
+     * @throws Exception
+     * @throws ServerNotAvailableException
+     */
+    public function primaryGroupID2Name(string $gid, string $dn) {
+        $cacheKey = 'primaryGroupIDtoName';
+        $groupNames = $this->access->connection->getFromCache($cacheKey);
+        if (!is_null($groupNames) && isset($groupNames[$gid])) {
+            return $groupNames[$gid];
+        }
+
+        $domainObjectSid = $this->access->getSID($dn);
+        if ($domainObjectSid === false) {
+            return false;
+        }
+
+        //we need to get the DN from LDAP
+        $filter = $this->access->combineFilterWithAnd([
+            $this->access->connection->ldapGroupFilter,
+            'objectsid=' . $domainObjectSid . '-' . $gid
+        ]);
+        return $this->getNameOfGroup($filter, $cacheKey) ?? false;
+    }
+
+    /**
+     * returns the entry's primary group ID
+     *
+     * @return string|bool
+     * @throws ServerNotAvailableException
+     */
+    private function getEntryGroupID(string $dn, string $attribute) {
+        $value = $this->access->readAttribute($dn, $attribute);
+        if (is_array($value) && !empty($value)) {
+            return $value[0];
+        }
+        return false;
+    }
+
+    /**
+     * @return string|bool
+     * @throws ServerNotAvailableException
+     */
+    public function getGroupPrimaryGroupID(string $dn) {
+        return $this->getEntryGroupID($dn, 'primaryGroupToken');
+    }
+
+    /**
+     * @return string|bool
+     * @throws ServerNotAvailableException
+     */
+    public function getUserPrimaryGroupIDs(string $dn) {
+        $primaryGroupID = false;
+        if ($this->access->connection->hasPrimaryGroups) {
+            $primaryGroupID = $this->getEntryGroupID($dn, 'primaryGroupID');
+            if ($primaryGroupID === false) {
+                $this->access->connection->hasPrimaryGroups = false;
+            }
+        }
+        return $primaryGroupID;
+    }
+
+    /**
+     * @throws Exception
+     * @throws ServerNotAvailableException
+     */
+    private function prepareFilterForUsersInPrimaryGroup(string $groupDN, string $search = ''): string {
+        $groupID = $this->getGroupPrimaryGroupID($groupDN);
+        if ($groupID === false) {
+            throw new Exception('Not a valid group');
+        }
+
+        $filterParts = [];
+        $filterParts[] = $this->access->getFilterForUserCount();
+        if ($search !== '') {
+            $filterParts[] = $this->access->getFilterPartForUserSearch($search);
+        }
+        $filterParts[] = 'primaryGroupID=' . $groupID;
+
+        return $this->access->combineFilterWithAnd($filterParts);
+    }
+
+    /**
+     * @throws ServerNotAvailableException
+     */
+    public function getUsersInPrimaryGroup(
+        string $groupDN,
+        string $search = '',
+        ?int $limit = -1,
+        ?int $offset = 0
+    ): array {
+        try {
+            $filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
+            $users = $this->access->fetchListOfUsers(
+                $filter,
+                [$this->access->connection->ldapUserDisplayName, 'dn'],
+                $limit,
+                $offset
+            );
+            return $this->access->nextcloudUserNames($users);
+        } catch (ServerNotAvailableException $e) {
+            throw $e;
+        } catch (Exception $e) {
+            return [];
+        }
+    }
+
+    /**
+     * @throws ServerNotAvailableException
+     */
+    public function countUsersInPrimaryGroup(
+        string $groupDN,
+        string $search = '',
+        int $limit = -1,
+        int $offset = 0
+    ): int {
+        try {
+            $filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
+            $users = $this->access->countUsers($filter, ['dn'], $limit, $offset);
+            return (int)$users;
+        } catch (ServerNotAvailableException $e) {
+            throw $e;
+        } catch (Exception $e) {
+            return 0;
+        }
+    }
+
+    /**
+     * @return string|bool
+     * @throws ServerNotAvailableException
+     */
+    public function getUserPrimaryGroup(string $dn) {
+        $groupID = $this->getUserPrimaryGroupIDs($dn);
+        if ($groupID !== false) {
+            $groupName = $this->primaryGroupID2Name($groupID, $dn);
+            if ($groupName !== false) {
+                return $groupName;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * This function fetches all groups a user belongs to. It does not check
+     * if the user exists at all.
+     *
+     * This function includes groups based on dynamic group membership.
+     *
+     * @param string $uid Name of the user
+     * @return array with group names
+     * @throws Exception
+     * @throws ServerNotAvailableException
+     */
+    public function getUserGroups($uid) {
+        if (!$this->enabled) {
+            return [];
+        }
+        $cacheKey = 'getUserGroups' . $uid;
+        $userGroups = $this->access->connection->getFromCache($cacheKey);
+        if (!is_null($userGroups)) {
+            return $userGroups;
+        }
+        $userDN = $this->access->username2dn($uid);
+        if (!$userDN) {
+            $this->access->connection->writeToCache($cacheKey, []);
+            return [];
+        }
+
+        $groups = [];
+        $primaryGroup = $this->getUserPrimaryGroup($userDN);
+        $gidGroupName = $this->getUserGroupByGid($userDN);
+
+        $dynamicGroupMemberURL = strtolower($this->access->connection->ldapDynamicGroupMemberURL);
+
+        if (!empty($dynamicGroupMemberURL)) {
+            // look through dynamic groups to add them to the result array if needed
+            $groupsToMatch = $this->access->fetchListOfGroups(
+                $this->access->connection->ldapGroupFilter, ['dn', $dynamicGroupMemberURL]);
+            foreach ($groupsToMatch as $dynamicGroup) {
+                if (!array_key_exists($dynamicGroupMemberURL, $dynamicGroup)) {
+                    continue;
+                }
+                $pos = strpos($dynamicGroup[$dynamicGroupMemberURL][0], '(');
+                if ($pos !== false) {
+                    $memberUrlFilter = substr($dynamicGroup[$dynamicGroupMemberURL][0], $pos);
+                    // apply filter via ldap search to see if this user is in this
+                    // dynamic group
+                    $userMatch = $this->access->readAttribute(
+                        $userDN,
+                        $this->access->connection->ldapUserDisplayName,
+                        $memberUrlFilter
+                    );
+                    if ($userMatch !== false) {
+                        // match found so this user is in this group
+                        $groupName = $this->access->dn2groupname($dynamicGroup['dn'][0]);
+                        if (is_string($groupName)) {
+                            // be sure to never return false if the dn could not be
+                            // resolved to a name, for whatever reason.
+                            $groups[] = $groupName;
+                        }
+                    }
+                } else {
+                    $this->logger->debug('No search filter found on member url of group {dn}',
+                        [
+                            'app' => 'user_ldap',
+                            'dn' => $dynamicGroup,
+                        ]
+                    );
+                }
+            }
+        }
+
+        // if possible, read out membership via memberOf. It's far faster than
+        // performing a search, which still is a fallback later.
+        // memberof doesn't support memberuid, so skip it here.
+        if ((int)$this->access->connection->hasMemberOfFilterSupport === 1
+            && (int)$this->access->connection->useMemberOfToDetectMembership === 1
+            && $this->ldapGroupMemberAssocAttr !== 'memberuid'
+            && $this->ldapGroupMemberAssocAttr !== 'zimbramailforwardingaddress') {
+            $groupDNs = $this->_getGroupDNsFromMemberOf($userDN);
+            if (is_array($groupDNs)) {
+                foreach ($groupDNs as $dn) {
+                    $groupName = $this->access->dn2groupname($dn);
+                    if (is_string($groupName)) {
+                        // be sure to never return false if the dn could not be
+                        // resolved to a name, for whatever reason.
+                        $groups[] = $groupName;
+                    }
+                }
+            }
+
+            if ($primaryGroup !== false) {
+                $groups[] = $primaryGroup;
+            }
+            if ($gidGroupName !== false) {
+                $groups[] = $gidGroupName;
+            }
+            $this->access->connection->writeToCache($cacheKey, $groups);
+            return $groups;
+        }
+
+        //uniqueMember takes DN, memberuid the uid, so we need to distinguish
+        switch ($this->ldapGroupMemberAssocAttr) {
+            case 'uniquemember':
+            case 'member':
+                $uid = $userDN;
+                break;
+
+            case 'memberuid':
+            case 'zimbramailforwardingaddress':
+                $result = $this->access->readAttribute($userDN, 'uid');
+                if ($result === false) {
+                    $this->logger->debug('No uid attribute found for DN {dn} on {host}',
+                        [
+                            'app' => 'user_ldap',
+                            'dn' => $userDN,
+                            'host' => $this->access->connection->ldapHost,
+                        ]
+                    );
+                    $uid = false;
+                } else {
+                    $uid = $result[0];
+                }
+                break;
+
+            default:
+                // just in case
+                $uid = $userDN;
+                break;
+        }
+
+        if ($uid !== false) {
+            if (isset($this->cachedGroupsByMember[$uid])) {
+                $groups = array_merge($groups, $this->cachedGroupsByMember[$uid]);
+            } else {
+                $groupsByMember = array_values($this->getGroupsByMember($uid));
+                $groupsByMember = $this->access->nextcloudGroupNames($groupsByMember);
+                $this->cachedGroupsByMember[$uid] = $groupsByMember;
+                $groups = array_merge($groups, $groupsByMember);
+            }
+        }
+
+        if ($primaryGroup !== false) {
+            $groups[] = $primaryGroup;
+        }
+        if ($gidGroupName !== false) {
+            $groups[] = $gidGroupName;
+        }
+
+        $groups = array_unique($groups, SORT_LOCALE_STRING);
+        $this->access->connection->writeToCache($cacheKey, $groups);
+
+        return $groups;
+    }
+
+    /**
+     * @throws ServerNotAvailableException
+     */
+    private function getGroupsByMember(string $dn, array &$seen = null): array {
+        if ($seen === null) {
+            $seen = [];
+        }
+        if (array_key_exists($dn, $seen)) {
+            // avoid loops
+            return [];
+        }
+        $allGroups = [];
+        $seen[$dn] = true;
+        $filter = $this->access->connection->ldapGroupMemberAssocAttr . '=' . $dn;
+
+        if ($this->ldapGroupMemberAssocAttr === 'zimbramailforwardingaddress') {
+            //in this case the member entries are email addresses
+            $filter .= '@*';
+        }
+
+        $nesting = (int)$this->access->connection->ldapNestedGroups;
+        if ($nesting === 0) {
+            $filter = $this->access->combineFilterWithAnd([$filter, $this->access->connection->ldapGroupFilter]);
+        }
+
+        $groups = $this->access->fetchListOfGroups($filter,
+            [strtolower($this->access->connection->ldapGroupMemberAssocAttr), $this->access->connection->ldapGroupDisplayName, 'dn']);
+        if (is_array($groups)) {
+            $fetcher = function ($dn, &$seen) {
+                if (is_array($dn) && isset($dn['dn'][0])) {
+                    $dn = $dn['dn'][0];
+                }
+                return $this->getGroupsByMember($dn, $seen);
+            };
+
+            if (empty($dn)) {
+                $dn = "";
+            }
+
+            $allGroups = $this->walkNestedGroups($dn, $fetcher, $groups);
+        }
+        $visibleGroups = $this->filterValidGroups($allGroups);
+        return array_intersect_key($allGroups, $visibleGroups);
+    }
+
+    /**
+     * get a list of all users in a group
+     *
+     * @param string $gid
+     * @param string $search
+     * @param int $limit
+     * @param int $offset
+     * @return array with user ids
+     * @throws Exception
+     * @throws ServerNotAvailableException
+     */
+    public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
+        if (!$this->enabled) {
+            return [];
+        }
+        if (!$this->groupExists($gid)) {
+            return [];
+        }
+        $search = $this->access->escapeFilterPart($search, true);
+        $cacheKey = 'usersInGroup-' . $gid . '-' . $search . '-' . $limit . '-' . $offset;
+        // check for cache of the exact query
+        $groupUsers = $this->access->connection->getFromCache($cacheKey);
+        if (!is_null($groupUsers)) {
+            return $groupUsers;
+        }
+
+        if ($limit === -1) {
+            $limit = null;
+        }
+        // check for cache of the query without limit and offset
+        $groupUsers = $this->access->connection->getFromCache('usersInGroup-' . $gid . '-' . $search);
+        if (!is_null($groupUsers)) {
+            $groupUsers = array_slice($groupUsers, $offset, $limit);
+            $this->access->connection->writeToCache($cacheKey, $groupUsers);
+            return $groupUsers;
+        }
+
+        $groupDN = $this->access->groupname2dn($gid);
+        if (!$groupDN) {
+            // group couldn't be found, return empty resultset
+            $this->access->connection->writeToCache($cacheKey, []);
+            return [];
+        }
+
+        $primaryUsers = $this->getUsersInPrimaryGroup($groupDN, $search, $limit, $offset);
+        $posixGroupUsers = $this->getUsersInGidNumber($groupDN, $search, $limit, $offset);
+        $members = $this->_groupMembers($groupDN);
+        if (!$members && empty($posixGroupUsers) && empty($primaryUsers)) {
+            //in case users could not be retrieved, return empty result set
+            $this->access->connection->writeToCache($cacheKey, []);
+            return [];
+        }
+
+        $groupUsers = [];
+        $attrs = $this->access->userManager->getAttributes(true);
+        foreach ($members as $member) {
+            switch ($this->ldapGroupMemberAssocAttr) {
+                case 'zimbramailforwardingaddress':
+                    //we get email addresses and need to convert them to uids
+                    $parts = explode('@', $member);
+                    $member = $parts[0];
+                    //no break needed because we just needed to remove the email part and now we have uids
+                case 'memberuid':
+                    //we got uids, need to get their DNs to 'translate' them to user names
+                    $filter = $this->access->combineFilterWithAnd([
+                        str_replace('%uid', trim($member), $this->access->connection->ldapLoginFilter),
+                        $this->access->combineFilterWithAnd([
+                            $this->access->getFilterPartForUserSearch($search),
+                            $this->access->connection->ldapUserFilter
+                        ])
+                    ]);
+                    $ldap_users = $this->access->fetchListOfUsers($filter, $attrs, 1);
+                    if (empty($ldap_users)) {
+                        break;
+                    }
+                    $groupUsers[] = $this->access->dn2username($ldap_users[0]['dn'][0]);
+                    break;
+                default:
+                    //we got DNs, check if we need to filter by search or we can give back all of them
+                    $uid = $this->access->dn2username($member);
+                    if (!$uid) {
+                        break;
+                    }
+
+                    $cacheKey = 'userExistsOnLDAP' . $uid;
+                    $userExists = $this->access->connection->getFromCache($cacheKey);
+                    if ($userExists === false) {
+                        break;
+                    }
+                    if ($userExists === null || $search !== '') {
+                        if (!$this->access->readAttribute($member,
+                            $this->access->connection->ldapUserDisplayName,
+                            $this->access->combineFilterWithAnd([
+                                $this->access->getFilterPartForUserSearch($search),
+                                $this->access->connection->ldapUserFilter
+                            ]))) {
+                            if ($search === '') {
+                                $this->access->connection->writeToCache($cacheKey, false);
+                            }
+                            break;
+                        }
+                        $this->access->connection->writeToCache($cacheKey, true);
+                    }
+                    $groupUsers[] = $uid;
+                    break;
+            }
+        }
+
+        $groupUsers = array_unique(array_merge($groupUsers, $primaryUsers, $posixGroupUsers));
+        natsort($groupUsers);
+        $this->access->connection->writeToCache('usersInGroup-' . $gid . '-' . $search, $groupUsers);
+        $groupUsers = array_slice($groupUsers, $offset, $limit);
+
+        $this->access->connection->writeToCache($cacheKey, $groupUsers);
+
+        return $groupUsers;
+    }
+
+    /**
+     * returns the number of users in a group, who match the search term
+     *
+     * @param string $gid the internal group name
+     * @param string $search optional, a search string
+     * @return int|bool
+     * @throws Exception
+     * @throws ServerNotAvailableException
+     */
+    public function countUsersInGroup($gid, $search = '') {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::COUNT_USERS)) {
+            return $this->groupPluginManager->countUsersInGroup($gid, $search);
+        }
+
+        $cacheKey = 'countUsersInGroup-' . $gid . '-' . $search;
+        if (!$this->enabled || !$this->groupExists($gid)) {
+            return false;
+        }
+        $groupUsers = $this->access->connection->getFromCache($cacheKey);
+        if (!is_null($groupUsers)) {
+            return $groupUsers;
+        }
+
+        $groupDN = $this->access->groupname2dn($gid);
+        if (!$groupDN) {
+            // group couldn't be found, return empty result set
+            $this->access->connection->writeToCache($cacheKey, false);
+            return false;
+        }
+
+        $members = $this->_groupMembers($groupDN);
+        $primaryUserCount = $this->countUsersInPrimaryGroup($groupDN, '');
+        if (!$members && $primaryUserCount === 0) {
+            //in case users could not be retrieved, return empty result set
+            $this->access->connection->writeToCache($cacheKey, false);
+            return false;
+        }
+
+        if ($search === '') {
+            $groupUsers = count($members) + $primaryUserCount;
+            $this->access->connection->writeToCache($cacheKey, $groupUsers);
+            return $groupUsers;
+        }
+        $search = $this->access->escapeFilterPart($search, true);
+        $isMemberUid =
+            ($this->ldapGroupMemberAssocAttr === 'memberuid' ||
+                $this->ldapGroupMemberAssocAttr === 'zimbramailforwardingaddress');
+
+        //we need to apply the search filter
+        //alternatives that need to be checked:
+        //a) get all users by search filter and array_intersect them
+        //b) a, but only when less than 1k 10k ?k users like it is
+        //c) put all DNs|uids in a LDAP filter, combine with the search string
+        //   and let it count.
+        //For now this is not important, because the only use of this method
+        //does not supply a search string
+        $groupUsers = [];
+        foreach ($members as $member) {
+            if ($isMemberUid) {
+                if ($this->ldapGroupMemberAssocAttr === 'zimbramailforwardingaddress') {
+                    //we get email addresses and need to convert them to uids
+                    $parts = explode('@', $member);
+                    $member = $parts[0];
+                }
+                //we got uids, need to get their DNs to 'translate' them to user names
+                $filter = $this->access->combineFilterWithAnd([
+                    str_replace('%uid', $member, $this->access->connection->ldapLoginFilter),
+                    $this->access->getFilterPartForUserSearch($search)
+                ]);
+                $ldap_users = $this->access->fetchListOfUsers($filter, ['dn'], 1);
+                if (count($ldap_users) < 1) {
+                    continue;
+                }
+                $groupUsers[] = $this->access->dn2username($ldap_users[0]);
+            } else {
+                //we need to apply the search filter now
+                if (!$this->access->readAttribute($member,
+                    $this->access->connection->ldapUserDisplayName,
+                    $this->access->getFilterPartForUserSearch($search))) {
+                    continue;
+                }
+                // dn2username will also check if the users belong to the allowed base
+                if ($ncGroupId = $this->access->dn2username($member)) {
+                    $groupUsers[] = $ncGroupId;
+                }
+            }
+        }
+
+        //and get users that have the group as primary
+        $primaryUsers = $this->countUsersInPrimaryGroup($groupDN, $search);
+
+        return count($groupUsers) + $primaryUsers;
+    }
+
+    /**
+     * get a list of all groups using a paged search
+     *
+     * @param string $search
+     * @param int $limit
+     * @param int $offset
+     * @return array with group names
+     *
+     * Returns a list with all groups
+     * Uses a paged search if available to override a
+     * server side search limit.
+     * (active directory has a limit of 1000 by default)
+     * @throws Exception
+     */
+    public function getGroups($search = '', $limit = -1, $offset = 0) {
+        if (!$this->enabled) {
+            return [];
+        }
+        $cacheKey = 'getGroups-' . $search . '-' . $limit . '-' . $offset;
+
+        //Check cache before driving unnecessary searches
+        $ldap_groups = $this->access->connection->getFromCache($cacheKey);
+        if (!is_null($ldap_groups)) {
+            return $ldap_groups;
+        }
+
+        // if we'd pass -1 to LDAP search, we'd end up in a Protocol
+        // error. With a limit of 0, we get 0 results. So we pass null.
+        if ($limit <= 0) {
+            $limit = null;
+        }
+        $filter = $this->access->combineFilterWithAnd([
+            $this->access->connection->ldapGroupFilter,
+            $this->access->getFilterPartForGroupSearch($search)
+        ]);
+        $ldap_groups = $this->access->fetchListOfGroups($filter,
+            [$this->access->connection->ldapGroupDisplayName, 'dn'],
+            $limit,
+            $offset);
+        $ldap_groups = $this->access->nextcloudGroupNames($ldap_groups);
+
+        $this->access->connection->writeToCache($cacheKey, $ldap_groups);
+        return $ldap_groups;
+    }
+
+    /**
+     * check if a group exists
+     *
+     * @param string $gid
+     * @return bool
+     * @throws ServerNotAvailableException
+     */
+    public function groupExists($gid) {
+        $groupExists = $this->access->connection->getFromCache('groupExists' . $gid);
+        if (!is_null($groupExists)) {
+            return (bool)$groupExists;
+        }
+
+        //getting dn, if false the group does not exist. If dn, it may be mapped
+        //only, requires more checking.
+        $dn = $this->access->groupname2dn($gid);
+        if (!$dn) {
+            $this->access->connection->writeToCache('groupExists' . $gid, false);
+            return false;
+        }
+
+        if (!$this->access->isDNPartOfBase($dn, $this->access->connection->ldapBaseGroups)) {
+            $this->access->connection->writeToCache('groupExists' . $gid, false);
+            return false;
+        }
+
+        //if group really still exists, we will be able to read its objectClass
+        if (!is_array($this->access->readAttribute($dn, '', $this->access->connection->ldapGroupFilter))) {
+            $this->access->connection->writeToCache('groupExists' . $gid, false);
+            return false;
+        }
+
+        $this->access->connection->writeToCache('groupExists' . $gid, true);
+        return true;
+    }
+
+    /**
+     * @throws ServerNotAvailableException
+     * @throws Exception
+     */
+    protected function filterValidGroups(array $listOfGroups): array {
+        $validGroupDNs = [];
+        foreach ($listOfGroups as $key => $item) {
+            $dn = is_string($item) ? $item : $item['dn'][0];
+            $gid = $this->access->dn2groupname($dn);
+            if (!$gid) {
+                continue;
+            }
+            if ($this->groupExists($gid)) {
+                $validGroupDNs[$key] = $item;
+            }
+        }
+        return $validGroupDNs;
+    }
+
+    /**
+     * Check if backend implements actions
+     *
+     * @param int $actions bitwise-or'ed actions
+     * @return boolean
+     *
+     * Returns the supported actions as int to be
+     * compared with GroupInterface::CREATE_GROUP etc.
+     */
+    public function implementsActions($actions) {
+        return (bool)((GroupInterface::COUNT_USERS |
+                $this->groupPluginManager->getImplementedActions()) & $actions);
+    }
+
+    /**
+     * Return access for LDAP interaction.
+     *
+     * @return Access instance of Access for LDAP interaction
+     */
+    public function getLDAPAccess($gid) {
+        return $this->access;
+    }
+
+    /**
+     * create a group
+     *
+     * @param string $gid
+     * @return bool
+     * @throws Exception
+     * @throws ServerNotAvailableException
+     */
+    public function createGroup($gid) {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::CREATE_GROUP)) {
+            if ($dn = $this->groupPluginManager->createGroup($gid)) {
+                //updates group mapping
+                $uuid = $this->access->getUUID($dn, false);
+                if (is_string($uuid)) {
+                    $this->access->mapAndAnnounceIfApplicable(
+                        $this->access->getGroupMapper(),
+                        $dn,
+                        $gid,
+                        $uuid,
+                        false
+                    );
+                    $this->access->cacheGroupExists($gid);
+                }
+            }
+            return $dn != null;
+        }
+        throw new Exception('Could not create group in LDAP backend.');
+    }
+
+    /**
+     * delete a group
+     *
+     * @param string $gid gid of the group to delete
+     * @return bool
+     * @throws Exception
+     */
+    public function deleteGroup($gid) {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::DELETE_GROUP)) {
+            if ($ret = $this->groupPluginManager->deleteGroup($gid)) {
+                #delete group in nextcloud internal db
+                $this->access->getGroupMapper()->unmap($gid);
+                $this->access->connection->writeToCache("groupExists" . $gid, false);
+            }
+            return $ret;
+        }
+        throw new Exception('Could not delete group in LDAP backend.');
+    }
+
+    /**
+     * Add a user to a group
+     *
+     * @param string $uid Name of the user to add to group
+     * @param string $gid Name of the group in which add the user
+     * @return bool
+     * @throws Exception
+     */
+    public function addToGroup($uid, $gid) {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::ADD_TO_GROUP)) {
+            if ($ret = $this->groupPluginManager->addToGroup($uid, $gid)) {
+                $this->access->connection->clearCache();
+                unset($this->cachedGroupMembers[$gid]);
+            }
+            return $ret;
+        }
+        throw new Exception('Could not add user to group in LDAP backend.');
+    }
+
+    /**
+     * Removes a user from a group
+     *
+     * @param string $uid Name of the user to remove from group
+     * @param string $gid Name of the group from which remove the user
+     * @return bool
+     * @throws Exception
+     */
+    public function removeFromGroup($uid, $gid) {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::REMOVE_FROM_GROUP)) {
+            if ($ret = $this->groupPluginManager->removeFromGroup($uid, $gid)) {
+                $this->access->connection->clearCache();
+                unset($this->cachedGroupMembers[$gid]);
+            }
+            return $ret;
+        }
+        throw new Exception('Could not remove user from group in LDAP backend.');
+    }
+
+    /**
+     * Gets group details
+     *
+     * @param string $gid Name of the group
+     * @return array|false
+     * @throws Exception
+     */
+    public function getGroupDetails($gid) {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::GROUP_DETAILS)) {
+            return $this->groupPluginManager->getGroupDetails($gid);
+        }
+        throw new Exception('Could not get group details in LDAP backend.');
+    }
+
+    /**
+     * Return LDAP connection resource from a cloned connection.
+     * The cloned connection needs to be closed manually.
+     * of the current access.
+     *
+     * @param string $gid
+     * @return resource of the LDAP connection
+     * @throws ServerNotAvailableException
+     */
+    public function getNewLDAPConnection($gid) {
+        $connection = clone $this->access->getConnection();
+        return $connection->getConnectionResource();
+    }
+
+    /**
+     * @throws ServerNotAvailableException
+     */
+    public function getDisplayName(string $gid): string {
+        if ($this->groupPluginManager instanceof IGetDisplayNameBackend) {
+            return $this->groupPluginManager->getDisplayName($gid);
+        }
+
+        $cacheKey = 'group_getDisplayName' . $gid;
+        if (!is_null($displayName = $this->access->connection->getFromCache($cacheKey))) {
+            return $displayName;
+        }
+
+        $displayName = $this->access->readAttribute(
+            $this->access->groupname2dn($gid),
+            $this->access->connection->ldapGroupDisplayName);
+
+        if ($displayName && (count($displayName) > 0)) {
+            $displayName = $displayName[0];
+            $this->access->connection->writeToCache($cacheKey, $displayName);
+            return $displayName;
+        }
+
+        return '';
+    }
 }

Spacing +38 added lines, -38 removed lines

@@ -100,10 +100,10 @@ 
 		if (!$this->enabled) {
 			return false;
 		}
-		$cacheKey = 'inGroup' . $uid . ':' . $gid;
+		$cacheKey = 'inGroup'.$uid.':'.$gid;
 		$inGroup = $this->access->connection->getFromCache($cacheKey);
 		if (!is_null($inGroup)) {
-			return (bool)$inGroup;
+			return (bool) $inGroup;
 		}
 
 		$userDN = $this->access->username2dn($uid);
@@ -112,7 +112,7 @@ 
 			return in_array($userDN, $this->cachedGroupMembers[$gid]);
 		}
 
-		$cacheKeyMembers = 'inGroup-members:' . $gid;
+		$cacheKeyMembers = 'inGroup-members:'.$gid;
 		$members = $this->access->connection->getFromCache($cacheKeyMembers);
 		if (!is_null($members)) {
 			$this->cachedGroupMembers[$gid] = $members;
@@ -240,7 +240,7 @@ 
 			return [];
 		}
 		// used extensively in cron job, caching makes sense for nested groups
-		$cacheKey = '_groupMembers' . $dnGroup;
+		$cacheKey = '_groupMembers'.$dnGroup;
 		$groupMembers = $this->access->connection->getFromCache($cacheKey);
 		if ($groupMembers !== null) {
 			return $groupMembers;
@@ -255,14 +255,14 @@ 
 			// compatibility hack with servers supporting :1.2.840.113556.1.4.1941:, and others)
 			$filter = $this->access->combineFilterWithAnd([
 				$this->access->connection->ldapUserFilter,
-				$this->access->connection->ldapUserDisplayName . '=*',
-				'memberof:1.2.840.113556.1.4.1941:=' . $dnGroup
+				$this->access->connection->ldapUserDisplayName.'=*',
+				'memberof:1.2.840.113556.1.4.1941:='.$dnGroup
 			]);
 			$memberRecords = $this->access->fetchListOfUsers(
 				$filter,
 				$this->access->userManager->getAttributes(true)
 			);
-			$result = array_reduce($memberRecords, function ($carry, $record) {
+			$result = array_reduce($memberRecords, function($carry, $record) {
 				$carry[] = $record['dn'][0];
 				return $carry;
 			}, []);
@@ -279,7 +279,7 @@ 
 		$seen[$dnGroup] = 1;
 		$members = $this->access->readAttribute($dnGroup, $this->access->connection->ldapGroupMemberAssocAttr);
 		if (is_array($members)) {
-			$fetcher = function ($memberDN, &$seen) {
+			$fetcher = function($memberDN, &$seen) {
 				return $this->_groupMembers($memberDN, $seen);
 			};
 			$allMembers = $this->walkNestedGroups($dnGroup, $fetcher, $members);
@@ -307,7 +307,7 @@ 
 			return [];
 		}
 
-		$fetcher = function ($groupDN) {
+		$fetcher = function($groupDN) {
 			if (isset($this->cachedNestedGroups[$groupDN])) {
 				$nestedGroups = $this->cachedNestedGroups[$groupDN];
 			} else {
@@ -325,7 +325,7 @@ 
 	}
 
 	private function walkNestedGroups(string $dn, Closure $fetcher, array $list): array {
-		$nesting = (int)$this->access->connection->ldapNestedGroups;
+		$nesting = (int) $this->access->connection->ldapNestedGroups;
 		// depending on the input, we either have a list of DNs or a list of LDAP records
 		// also, the output expects either DNs or records. Testing the first element should suffice.
 		$recordMode = is_array($list) && isset($list[0]) && is_array($list[0]) && isset($list[0]['dn'][0]);
@@ -333,7 +333,7 @@ 
 		if ($nesting !== 1) {
 			if ($recordMode) {
 				// the keys are numeric, but should hold the DN
-				return array_reduce($list, function ($transformed, $record) use ($dn) {
+				return array_reduce($list, function($transformed, $record) use ($dn) {
 					if ($record['dn'][0] != $dn) {
 						$transformed[$record['dn'][0]] = $record;
 					}
@@ -366,7 +366,7 @@ 
 	 * @throws ServerNotAvailableException
 	 */
 	public function gidNumber2Name(string $gid, string $dn) {
-		$cacheKey = 'gidNumberToName' . $gid;
+		$cacheKey = 'gidNumberToName'.$gid;
 		$groupName = $this->access->connection->getFromCache($cacheKey);
 		if (!is_null($groupName) && isset($groupName)) {
 			return $groupName;
@@ -376,7 +376,7 @@ 
 		$filter = $this->access->combineFilterWithAnd([
 			$this->access->connection->ldapGroupFilter,
 			'objectClass=posixGroup',
-			$this->access->connection->ldapGidNumber . '=' . $gid
+			$this->access->connection->ldapGidNumber.'='.$gid
 		]);
 		return $this->getNameOfGroup($filter, $cacheKey) ?? false;
 	}
@@ -456,7 +456,7 @@ 
 		if ($search !== '') {
 			$filterParts[] = $this->access->getFilterPartForUserSearch($search);
 		}
-		$filterParts[] = $this->access->connection->ldapGidNumber . '=' . $groupID;
+		$filterParts[] = $this->access->connection->ldapGidNumber.'='.$groupID;
 
 		return $this->access->combineFilterWithAnd($filterParts);
 	}
@@ -526,7 +526,7 @@ 
 		//we need to get the DN from LDAP
 		$filter = $this->access->combineFilterWithAnd([
 			$this->access->connection->ldapGroupFilter,
-			'objectsid=' . $domainObjectSid . '-' . $gid
+			'objectsid='.$domainObjectSid.'-'.$gid
 		]);
 		return $this->getNameOfGroup($filter, $cacheKey) ?? false;
 	}
@@ -583,7 +583,7 @@ 
 		if ($search !== '') {
 			$filterParts[] = $this->access->getFilterPartForUserSearch($search);
 		}
-		$filterParts[] = 'primaryGroupID=' . $groupID;
+		$filterParts[] = 'primaryGroupID='.$groupID;
 
 		return $this->access->combineFilterWithAnd($filterParts);
 	}
@@ -625,7 +625,7 @@ 
 		try {
 			$filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
 			$users = $this->access->countUsers($filter, ['dn'], $limit, $offset);
-			return (int)$users;
+			return (int) $users;
 		} catch (ServerNotAvailableException $e) {
 			throw $e;
 		} catch (Exception $e) {
@@ -664,7 +664,7 @@ 
 		if (!$this->enabled) {
 			return [];
 		}
-		$cacheKey = 'getUserGroups' . $uid;
+		$cacheKey = 'getUserGroups'.$uid;
 		$userGroups = $this->access->connection->getFromCache($cacheKey);
 		if (!is_null($userGroups)) {
 			return $userGroups;
@@ -722,8 +722,8 @@ 
 		// if possible, read out membership via memberOf. It's far faster than
 		// performing a search, which still is a fallback later.
 		// memberof doesn't support memberuid, so skip it here.
-		if ((int)$this->access->connection->hasMemberOfFilterSupport === 1
-			&& (int)$this->access->connection->useMemberOfToDetectMembership === 1
+		if ((int) $this->access->connection->hasMemberOfFilterSupport === 1
+			&& (int) $this->access->connection->useMemberOfToDetectMembership === 1
 			&& $this->ldapGroupMemberAssocAttr !== 'memberuid'
 			&& $this->ldapGroupMemberAssocAttr !== 'zimbramailforwardingaddress') {
 			$groupDNs = $this->_getGroupDNsFromMemberOf($userDN);
@@ -815,14 +815,14 @@ 
 		}
 		$allGroups = [];
 		$seen[$dn] = true;
-		$filter = $this->access->connection->ldapGroupMemberAssocAttr . '=' . $dn;
+		$filter = $this->access->connection->ldapGroupMemberAssocAttr.'='.$dn;
 
 		if ($this->ldapGroupMemberAssocAttr === 'zimbramailforwardingaddress') {
 			//in this case the member entries are email addresses
 			$filter .= '@*';
 		}
 
-		$nesting = (int)$this->access->connection->ldapNestedGroups;
+		$nesting = (int) $this->access->connection->ldapNestedGroups;
 		if ($nesting === 0) {
 			$filter = $this->access->combineFilterWithAnd([$filter, $this->access->connection->ldapGroupFilter]);
 		}
@@ -830,7 +830,7 @@ 
 		$groups = $this->access->fetchListOfGroups($filter,
 			[strtolower($this->access->connection->ldapGroupMemberAssocAttr), $this->access->connection->ldapGroupDisplayName, 'dn']);
 		if (is_array($groups)) {
-			$fetcher = function ($dn, &$seen) {
+			$fetcher = function($dn, &$seen) {
 				if (is_array($dn) && isset($dn['dn'][0])) {
 					$dn = $dn['dn'][0];
 				}
@@ -866,7 +866,7 @@ 
 			return [];
 		}
 		$search = $this->access->escapeFilterPart($search, true);
-		$cacheKey = 'usersInGroup-' . $gid . '-' . $search . '-' . $limit . '-' . $offset;
+		$cacheKey = 'usersInGroup-'.$gid.'-'.$search.'-'.$limit.'-'.$offset;
 		// check for cache of the exact query
 		$groupUsers = $this->access->connection->getFromCache($cacheKey);
 		if (!is_null($groupUsers)) {
@@ -877,7 +877,7 @@ 
 			$limit = null;
 		}
 		// check for cache of the query without limit and offset
-		$groupUsers = $this->access->connection->getFromCache('usersInGroup-' . $gid . '-' . $search);
+		$groupUsers = $this->access->connection->getFromCache('usersInGroup-'.$gid.'-'.$search);
 		if (!is_null($groupUsers)) {
 			$groupUsers = array_slice($groupUsers, $offset, $limit);
 			$this->access->connection->writeToCache($cacheKey, $groupUsers);
@@ -931,7 +931,7 @@ 
 						break;
 					}
 
-					$cacheKey = 'userExistsOnLDAP' . $uid;
+					$cacheKey = 'userExistsOnLDAP'.$uid;
 					$userExists = $this->access->connection->getFromCache($cacheKey);
 					if ($userExists === false) {
 						break;
@@ -957,7 +957,7 @@ 
 
 		$groupUsers = array_unique(array_merge($groupUsers, $primaryUsers, $posixGroupUsers));
 		natsort($groupUsers);
-		$this->access->connection->writeToCache('usersInGroup-' . $gid . '-' . $search, $groupUsers);
+		$this->access->connection->writeToCache('usersInGroup-'.$gid.'-'.$search, $groupUsers);
 		$groupUsers = array_slice($groupUsers, $offset, $limit);
 
 		$this->access->connection->writeToCache($cacheKey, $groupUsers);
@@ -979,7 +979,7 @@ 
 			return $this->groupPluginManager->countUsersInGroup($gid, $search);
 		}
 
-		$cacheKey = 'countUsersInGroup-' . $gid . '-' . $search;
+		$cacheKey = 'countUsersInGroup-'.$gid.'-'.$search;
 		if (!$this->enabled || !$this->groupExists($gid)) {
 			return false;
 		}
@@ -1077,7 +1077,7 @@ 
 		if (!$this->enabled) {
 			return [];
 		}
-		$cacheKey = 'getGroups-' . $search . '-' . $limit . '-' . $offset;
+		$cacheKey = 'getGroups-'.$search.'-'.$limit.'-'.$offset;
 
 		//Check cache before driving unnecessary searches
 		$ldap_groups = $this->access->connection->getFromCache($cacheKey);
@@ -1112,31 +1112,31 @@ 
 	 * @throws ServerNotAvailableException
 	 */
 	public function groupExists($gid) {
-		$groupExists = $this->access->connection->getFromCache('groupExists' . $gid);
+		$groupExists = $this->access->connection->getFromCache('groupExists'.$gid);
 		if (!is_null($groupExists)) {
-			return (bool)$groupExists;
+			return (bool) $groupExists;
 		}
 
 		//getting dn, if false the group does not exist. If dn, it may be mapped
 		//only, requires more checking.
 		$dn = $this->access->groupname2dn($gid);
 		if (!$dn) {
-			$this->access->connection->writeToCache('groupExists' . $gid, false);
+			$this->access->connection->writeToCache('groupExists'.$gid, false);
 			return false;
 		}
 
 		if (!$this->access->isDNPartOfBase($dn, $this->access->connection->ldapBaseGroups)) {
-			$this->access->connection->writeToCache('groupExists' . $gid, false);
+			$this->access->connection->writeToCache('groupExists'.$gid, false);
 			return false;
 		}
 
 		//if group really still exists, we will be able to read its objectClass
 		if (!is_array($this->access->readAttribute($dn, '', $this->access->connection->ldapGroupFilter))) {
-			$this->access->connection->writeToCache('groupExists' . $gid, false);
+			$this->access->connection->writeToCache('groupExists'.$gid, false);
 			return false;
 		}
 
-		$this->access->connection->writeToCache('groupExists' . $gid, true);
+		$this->access->connection->writeToCache('groupExists'.$gid, true);
 		return true;
 	}
 
@@ -1169,7 +1169,7 @@ 
 	 * compared with GroupInterface::CREATE_GROUP etc.
 	 */
 	public function implementsActions($actions) {
-		return (bool)((GroupInterface::COUNT_USERS |
+		return (bool) ((GroupInterface::COUNT_USERS |
 				$this->groupPluginManager->getImplementedActions()) & $actions);
 	}
 
@@ -1223,7 +1223,7 @@ 
 			if ($ret = $this->groupPluginManager->deleteGroup($gid)) {
 				#delete group in nextcloud internal db
 				$this->access->getGroupMapper()->unmap($gid);
-				$this->access->connection->writeToCache("groupExists" . $gid, false);
+				$this->access->connection->writeToCache("groupExists".$gid, false);
 			}
 			return $ret;
 		}
@@ -1304,7 +1304,7 @@ 
 			return $this->groupPluginManager->getDisplayName($gid);
 		}
 
-		$cacheKey = 'group_getDisplayName' . $gid;
+		$cacheKey = 'group_getDisplayName'.$gid;
 		if (!is_null($displayName = $this->access->connection->getFromCache($cacheKey))) {
 			return $displayName;
 		}