Merge pull request #8532 from nextcloud/8499-stable13

[stable13]  Avoid fruitless login attempts

Author: MorrisJobke

apps/user_ldap/lib/Connection.php

@@ -86,6 +86,8 @@ class Connection extends LDAPUtility {
 
 	protected $ignoreValidation = false;
 
+	protected $bindResult = [];
+
 	/**
 	 * Constructor
 	 * @param ILDAPWrapper $ldap
@@ -113,7 +115,8 @@ public function __construct(ILDAPWrapper $ldap, $configPrefix = '', $configID =
 	public function __destruct() {
 		if(!$this->dontDestruct && $this->ldap->isResource($this->ldapConnectionRes)) {
 			@$this->ldap->unbind($this->ldapConnectionRes);
-		};
+		}
+		$this->bindResult = [];
 	}
 
 	/**
@@ -202,6 +205,7 @@ public function resetConnectionResource() {
 		if(!is_null($this->ldapConnectionRes)) {
 			@$this->ldap->unbind($this->ldapConnectionRes);
 			$this->ldapConnectionRes = null;
+			$this->bindResult = [];
 		}
 	}
 
@@ -560,6 +564,7 @@ private function establishConnection() {
 			if($isBackupHost && ($error !== 0 || $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;
@@ -612,13 +617,35 @@ public function bind() {
 		if(!$this->configuration->ldapConfigurationActive) {
 			return false;
 		}
-		$cr = $this->getConnectionResource();
+		$cr = $this->ldapConnectionRes;
 		if(!$this->ldap->isResource($cr)) {
-			return false;
+			$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);
 

apps/user_ldap/tests/ConnectionTest.php

@@ -174,7 +174,7 @@ public function testBindWithInvalidCredentials() {
 			->method('connect')
 			->will($this->returnValue('ldapResource'));
 
-		$this->ldap->expects($this->exactly(2))
+		$this->ldap->expects($this->once())
 			->method('bind')
 			->will($this->returnValue(false));
 

core/Controller/LoginController.php

@@ -256,13 +256,15 @@ public function tryLogin($user, $password, $redirect_url, $remember_login = fals
 			$users = $this->userManager->getByEmail($user);
 			// we only allow login by email if unique
 			if (count($users) === 1) {
+				$previousUser = $user;
 				$user = $users[0]->getUID();
-				$loginResult = $this->userManager->checkPassword($user, $password);
-			} else {
-				$this->logger->warning('Login failed: \''. $user .'\' (Remote IP: \''. $this->request->getRemoteAddress(). '\')', ['app' => 'core']);
+				if($user !== $previousUser) {
+					$loginResult = $this->userManager->checkPassword($user, $password);
+				}
 			}
 		}
 		if ($loginResult === false) {
+			$this->logger->warning('Login failed: \''. $user .'\' (Remote IP: \''. $this->request->getRemoteAddress(). '\')', ['app' => 'core']);
 			// Read current user and append if possible - we need to return the unmodified user otherwise we will leak the login name
 			$args = !is_null($user) ? ['user' => $originalUser] : [];
 			if (!is_null($redirect_url)) {