nextcloud / server

apps/user_ldap/lib/Connection.php

Indentation +623 added lines, -623 removed lines

@@ -63,628 +63,628 @@
  * @property string ldapEmailAttribute
  */
 class Connection extends LDAPUtility {
-	private $ldapConnectionRes = null;
-	private $configPrefix;
-	private $configID;
-	private $configured = false;
-	private $hasPagedResultSupport = true;
-	//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());
-		$this->hasPagedResultSupport =
-			(int)$this->configuration->ldapPagingSize !== 0
-			|| $this->ldap->hasPagedResultSupport();
-	}
-
-	public function __destruct() {
-		if(!$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;
-	}
-
-	/**
-	 * @param string $name
-	 * @return bool|mixed
-	 */
-	public function __get($name) {
-		if(!$this->configured) {
-			$this->readConfiguration();
-		}
-
-		if($name === 'hasPagedResultSupport') {
-			return $this->hasPagedResultSupport;
-		}
-
-		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) {
-			$this->init();
-		} else if(!$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 = array();
-		}
-		$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();
-		$result = array();
-		foreach($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
-				default:
-					$result[$dbkey] = $config[$configkey];
-			}
-		}
-		return $result;
-	}
-
-	private function doSoftValidation() {
-		//if User or Group Base are not set, take over Base DN setting
-		foreach(array('ldapBaseUsers', 'ldapBaseGroups') as $keyBase) {
-			$val = $this->configuration->$keyBase;
-			if(empty($val)) {
-				$this->configuration->$keyBase = $this->configuration->ldapBase;
-			}
-		}
-
-		foreach(array('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
-		$saKeys = array('ldapAttributesForUserSearch',
-						'ldapAttributesForGroupSearch');
-		foreach($saKeys as $key) {
-			$val = $this->configuration->$key;
-			if(is_array($val) && count($val) === 1 && empty($val[0])) {
-				$this->configuration->$key = array();
-			}
-		}
-
-		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
-		$options = array('ldapHost', 'ldapPort', 'ldapUserDisplayName',
-						 'ldapGroupDisplayName', 'ldapLoginFilter');
-		foreach($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
-			if($errno !== 0x00 && $errno !== 0x31) {
-				$this->ldapConnectionRes = null;
-			}
-
-			return false;
-		}
-		return true;
-	}
+    private $ldapConnectionRes = null;
+    private $configPrefix;
+    private $configID;
+    private $configured = false;
+    private $hasPagedResultSupport = true;
+    //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());
+        $this->hasPagedResultSupport =
+            (int)$this->configuration->ldapPagingSize !== 0
+            || $this->ldap->hasPagedResultSupport();
+    }
+
+    public function __destruct() {
+        if(!$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;
+    }
+
+    /**
+     * @param string $name
+     * @return bool|mixed
+     */
+    public function __get($name) {
+        if(!$this->configured) {
+            $this->readConfiguration();
+        }
+
+        if($name === 'hasPagedResultSupport') {
+            return $this->hasPagedResultSupport;
+        }
+
+        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) {
+            $this->init();
+        } else if(!$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 = array();
+        }
+        $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();
+        $result = array();
+        foreach($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
+                default:
+                    $result[$dbkey] = $config[$configkey];
+            }
+        }
+        return $result;
+    }
+
+    private function doSoftValidation() {
+        //if User or Group Base are not set, take over Base DN setting
+        foreach(array('ldapBaseUsers', 'ldapBaseGroups') as $keyBase) {
+            $val = $this->configuration->$keyBase;
+            if(empty($val)) {
+                $this->configuration->$keyBase = $this->configuration->ldapBase;
+            }
+        }
+
+        foreach(array('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
+        $saKeys = array('ldapAttributesForUserSearch',
+                        'ldapAttributesForGroupSearch');
+        foreach($saKeys as $key) {
+            $val = $this->configuration->$key;
+            if(is_array($val) && count($val) === 1 && empty($val[0])) {
+                $this->configuration->$key = array();
+            }
+        }
+
+        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
+        $options = array('ldapHost', 'ldapPort', 'ldapUserDisplayName',
+                            'ldapGroupDisplayName', 'ldapLoginFilter');
+        foreach($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
+            if($errno !== 0x00 && $errno !== 0x31) {
+                $this->ldapConnectionRes = null;
+            }
+
+            return false;
+        }
+        return true;
+    }
 
 }