Merge pull request #9517 from nextcloud/feature/noid/improve_oauth_handling

Improve OAuth handling

9 files changed, 518 insertions, 56 deletions

diff --git a/apps/oauth2/appinfo/info.xml b/apps/oauth2/appinfo/info.xml
index ac18b5cdb94..43d0cf72372 100644
--- a/apps/oauth2/appinfo/info.xml
+++ b/apps/oauth2/appinfo/info.xml
@@ -5,7 +5,7 @@
 	<name>OAuth 2.0</name>
 	<summary>Allows OAuth2 compatible authentication from other web applications.</summary>
 	<description>The OAuth2 app allows administrators to configure the built-in authentication workflow to also allow OAuth2 compatible authentication from other web applications.</description>
-	<version>1.2.0</version>
+	<version>1.2.1</version>
 	<licence>agpl</licence>
 	<author>Lukas Reschke</author>
 	<namespace>OAuth2</namespace>
@@ -20,6 +20,12 @@
 		<nextcloud min-version="14" max-version="14" />
 	</dependencies>
 
+	<repair-steps>
+		<post-migration>
+			<step>OCA\OAuth2\Migration\SetTokenExpiration</step>
+		</post-migration>
+	</repair-steps>
+
 	<settings>
 		<admin>OCA\OAuth2\Settings\Admin</admin>
 	</settings>
diff --git a/apps/oauth2/composer/composer/autoload_classmap.php b/apps/oauth2/composer/composer/autoload_classmap.php
index 97c8098caa3..c933a1bf21e 100644
--- a/apps/oauth2/composer/composer/autoload_classmap.php
+++ b/apps/oauth2/composer/composer/autoload_classmap.php
@@ -15,5 +15,6 @@ return array(
     'OCA\\OAuth2\\Db\\ClientMapper' => $baseDir . '/../lib/Db/ClientMapper.php',
     'OCA\\OAuth2\\Exceptions\\AccessTokenNotFoundException' => $baseDir . '/../lib/Exceptions/AccessTokenNotFoundException.php',
     'OCA\\OAuth2\\Exceptions\\ClientNotFoundException' => $baseDir . '/../lib/Exceptions/ClientNotFoundException.php',
+    'OCA\\OAuth2\\Migration\\SetTokenExpiration' => $baseDir . '/../lib/Migration/SetTokenExpiration.php',
     'OCA\\OAuth2\\Settings\\Admin' => $baseDir . '/../lib/Settings/Admin.php',
 );
diff --git a/apps/oauth2/composer/composer/autoload_static.php b/apps/oauth2/composer/composer/autoload_static.php
index ec48d6d0ce0..aaac9e4f6d8 100644
--- a/apps/oauth2/composer/composer/autoload_static.php
+++ b/apps/oauth2/composer/composer/autoload_static.php
@@ -30,6 +30,7 @@ class ComposerStaticInitOAuth2
         'OCA\\OAuth2\\Db\\ClientMapper' => __DIR__ . '/..' . '/../lib/Db/ClientMapper.php',
         'OCA\\OAuth2\\Exceptions\\AccessTokenNotFoundException' => __DIR__ . '/..' . '/../lib/Exceptions/AccessTokenNotFoundException.php',
         'OCA\\OAuth2\\Exceptions\\ClientNotFoundException' => __DIR__ . '/..' . '/../lib/Exceptions/ClientNotFoundException.php',
+        'OCA\\OAuth2\\Migration\\SetTokenExpiration' => __DIR__ . '/..' . '/../lib/Migration/SetTokenExpiration.php',
         'OCA\\OAuth2\\Settings\\Admin' => __DIR__ . '/..' . '/../lib/Settings/Admin.php',
     );
 
diff --git a/apps/oauth2/lib/Controller/LoginRedirectorController.php b/apps/oauth2/lib/Controller/LoginRedirectorController.php
index 9237b4b1b3c..8e6d6d55e2d 100644
--- a/apps/oauth2/lib/Controller/LoginRedirectorController.php
+++ b/apps/oauth2/lib/Controller/LoginRedirectorController.php
@@ -61,11 +61,20 @@ class LoginRedirectorController extends Controller {
 	 *
 	 * @param string $client_id
 	 * @param string $state
+	 * @param string $response_type
 	 * @return RedirectResponse
 	 */
 	public function authorize($client_id,
-							  $state) {
+							  $state,
+							  $response_type) {
 		$client = $this->clientMapper->getByIdentifier($client_id);
+
+		if ($response_type !== 'code') {
+			//Fail
+			$url = $client->getRedirectUri() . '?error=unsupported_response_type&state=' . $state;
+			return new RedirectResponse($url);
+		}
+
 		$this->session->set('oauth.state', $state);
 
 		$targetUrl = $this->urlGenerator->linkToRouteAbsolute(
diff --git a/apps/oauth2/lib/Controller/OauthApiController.php b/apps/oauth2/lib/Controller/OauthApiController.php
index b97d85ae3e6..8c96a3feee1 100644
--- a/apps/oauth2/lib/Controller/OauthApiController.php
+++ b/apps/oauth2/lib/Controller/OauthApiController.php
@@ -21,10 +21,17 @@
 
 namespace OCA\OAuth2\Controller;
 
-use OC\Authentication\Token\DefaultTokenMapper;
+use OC\Authentication\Exceptions\InvalidTokenException;
+use OC\Authentication\Token\ExpiredTokenException;
+use OC\Authentication\Token\IProvider as TokenProvider;
 use OCA\OAuth2\Db\AccessTokenMapper;
+use OCA\OAuth2\Db\ClientMapper;
+use OCA\OAuth2\Exceptions\AccessTokenNotFoundException;
+use OCA\OAuth2\Exceptions\ClientNotFoundException;
 use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
+use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\IRequest;
 use OCP\Security\ICrypto;
 use OCP\Security\ISecureRandom;
@@ -32,56 +39,133 @@ use OCP\Security\ISecureRandom;
 class OauthApiController extends Controller {
 	/** @var AccessTokenMapper */
 	private $accessTokenMapper;
+	/** @var ClientMapper */
+	private $clientMapper;
 	/** @var ICrypto */
 	private $crypto;
-	/** @var DefaultTokenMapper */
-	private $defaultTokenMapper;
+	/** @var TokenProvider */
+	private $tokenProvider;
 	/** @var ISecureRandom */
 	private $secureRandom;
+	/** @var ITimeFactory */
+	private $time;
 
 	/**
 	 * @param string $appName
 	 * @param IRequest $request
 	 * @param ICrypto $crypto
 	 * @param AccessTokenMapper $accessTokenMapper
-	 * @param DefaultTokenMapper $defaultTokenMapper
+	 * @param ClientMapper $clientMapper
+	 * @param TokenProvider $tokenProvider
 	 * @param ISecureRandom $secureRandom
+	 * @param ITimeFactory $time
 	 */
 	public function __construct($appName,
 								IRequest $request,
 								ICrypto $crypto,
 								AccessTokenMapper $accessTokenMapper,
-								DefaultTokenMapper $defaultTokenMapper,
-								ISecureRandom $secureRandom) {
+								ClientMapper $clientMapper,
+								TokenProvider $tokenProvider,
+								ISecureRandom $secureRandom,
+								ITimeFactory $time) {
 		parent::__construct($appName, $request);
 		$this->crypto = $crypto;
 		$this->accessTokenMapper = $accessTokenMapper;
-		$this->defaultTokenMapper = $defaultTokenMapper;
+		$this->clientMapper = $clientMapper;
+		$this->tokenProvider = $tokenProvider;
 		$this->secureRandom = $secureRandom;
+		$this->time = $time;
 	}
 
 	/**
 	 * @PublicPage
 	 * @NoCSRFRequired
 	 *
+	 * @param string $grant_type
 	 * @param string $code
+	 * @param string $refresh_token
+	 * @param string $client_id
+	 * @param string $client_secret
 	 * @return JSONResponse
 	 */
-	public function getToken($code) {
-		$accessToken = $this->accessTokenMapper->getByCode($code);
+	public function getToken($grant_type, $code, $refresh_token, $client_id, $client_secret) {
+
+		// We only handle two types
+		if ($grant_type !== 'authorization_code' && $grant_type !== 'refresh_token') {
+			return new JSONResponse([
+				'error' => 'invalid_grant',
+			], Http::STATUS_BAD_REQUEST);
+		}
+
+		// We handle the initial and refresh tokens the same way
+		if ($grant_type === 'refresh_token' ) {
+			$code = $refresh_token;
+		}
+
+		try {
+			$accessToken = $this->accessTokenMapper->getByCode($code);
+		} catch (AccessTokenNotFoundException $e) {
+			return new JSONResponse([
+				'error' => 'invalid_request',
+			], Http::STATUS_BAD_REQUEST);
+		}
+
+		try {
+			$client = $this->clientMapper->getByUid($accessToken->getClientId());
+		} catch (ClientNotFoundException $e) {
+			return new JSONResponse([
+				'error' => 'invalid_request',
+			], Http::STATUS_BAD_REQUEST);
+		}
+
+		// The client id and secret must match. Else we don't provide an access token!
+		if ($client->getClientIdentifier() !== $client_id || $client->getSecret() !== $client_secret) {
+			return new JSONResponse([
+				'error' => 'invalid_client',
+			], Http::STATUS_BAD_REQUEST);
+		}
+
 		$decryptedToken = $this->crypto->decrypt($accessToken->getEncryptedToken(), $code);
-		$newCode = $this->secureRandom->generate(128);
+
+		// Obtain the appToken assoicated
+		try {
+			$appToken = $this->tokenProvider->getTokenById($accessToken->getTokenId());
+		} catch (ExpiredTokenException $e) {
+			$appToken = $e->getToken();
+		} catch (InvalidTokenException $e) {
+			//We can't do anything...
+			$this->accessTokenMapper->delete($accessToken);
+			return new JSONResponse([
+				'error' => 'invalid_request',
+			], Http::STATUS_BAD_REQUEST);
+		}
+
+		// Rotate the apptoken (so the old one becomes invalid basically)
+		$newToken = $this->secureRandom->generate(72, ISecureRandom::CHAR_UPPER.ISecureRandom::CHAR_LOWER.ISecureRandom::CHAR_DIGITS);
+
+		$appToken = $this->tokenProvider->rotate(
+			$appToken,
+			$decryptedToken,
+			$newToken
+		);
+
+		// Expiration is in 1 hour again
+		$appToken->setExpires($this->time->getTime() + 3600);
+		$this->tokenProvider->updateToken($appToken);
+
+		// Generate a new refresh token and encrypt the new apptoken in the DB
+		$newCode = $this->secureRandom->generate(128, ISecureRandom::CHAR_UPPER.ISecureRandom::CHAR_LOWER.ISecureRandom::CHAR_DIGITS);
 		$accessToken->setHashedCode(hash('sha512', $newCode));
-		$accessToken->setEncryptedToken($this->crypto->encrypt($decryptedToken, $newCode));
+		$accessToken->setEncryptedToken($this->crypto->encrypt($newToken, $newCode));
 		$this->accessTokenMapper->update($accessToken);
 
 		return new JSONResponse(
 			[
-				'access_token' => $decryptedToken,
+				'access_token' => $newToken,
 				'token_type' => 'Bearer',
 				'expires_in' => 3600,
 				'refresh_token' => $newCode,
-				'user_id' => $this->defaultTokenMapper->getTokenById($accessToken->getTokenId())->getUID(),
+				'user_id' => $appToken->getUID(),
 			]
 		);
 	}
diff --git a/apps/oauth2/lib/Migration/SetTokenExpiration.php b/apps/oauth2/lib/Migration/SetTokenExpiration.php
new file mode 100644
index 00000000000..54add100fa7
--- /dev/null
+++ b/apps/oauth2/lib/Migration/SetTokenExpiration.php
@@ -0,0 +1,77 @@
+<?php
+/**
+ * @copyright Copyright 2018, Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @author Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\OAuth2\Migration;
+
+use OC\Authentication\Exceptions\InvalidTokenException;
+use OC\Authentication\Token\IProvider as TokenProvider;
+use OCA\OAuth2\Db\AccessToken;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\IDBConnection;
+use OCP\Migration\IOutput;
+use OCP\Migration\IRepairStep;
+
+class SetTokenExpiration implements IRepairStep {
+
+	/** @var IDBConnection */
+	private $connection;
+
+	/** @var ITimeFactory */
+	private $time;
+
+	/** @var TokenProvider */
+	private $tokenProvider;
+
+	public function __construct(IDBConnection $connection,
+								ITimeFactory $timeFactory,
+								TokenProvider $tokenProvider) {
+		$this->connection = $connection;
+		$this->time = $timeFactory;
+		$this->tokenProvider = $tokenProvider;
+	}
+
+	public function getName() {
+		return 'Update OAuth token expiration times';
+	}
+
+	public function run(IOutput $output) {
+		$qb = $this->connection->getQueryBuilder();
+		$qb->select('*')
+			->from('oauth2_access_tokens');
+
+		$cursor = $qb->execute();
+
+		while($row = $cursor->fetch()) {
+			$token = AccessToken::fromRow($row);
+			try {
+				$appToken = $this->tokenProvider->getTokenById($token->getTokenId());
+				$appToken->setExpires($this->time->getTime() + 3600);
+				$this->tokenProvider->updateToken($appToken);
+			} catch (InvalidTokenException $e) {
+				//Skip this token
+			}
+		}
+		$cursor->closeCursor();
+	}
+
+}
diff --git a/apps/oauth2/tests/Controller/LoginRedirectorControllerTest.php b/apps/oauth2/tests/Controller/LoginRedirectorControllerTest.php
index b33d3379be4..584e3ebed54 100644
--- a/apps/oauth2/tests/Controller/LoginRedirectorControllerTest.php
+++ b/apps/oauth2/tests/Controller/LoginRedirectorControllerTest.php
@@ -86,6 +86,24 @@ class LoginRedirectorControllerTest extends TestCase {
 			->willReturn('https://example.com/?clientIdentifier=foo');
 
 		$expected = new RedirectResponse('https://example.com/?clientIdentifier=foo');
-		$this->assertEquals($expected, $this->loginRedirectorController->authorize('MyClientId', 'MyState'));
+		$this->assertEquals($expected, $this->loginRedirectorController->authorize('MyClientId', 'MyState', 'code'));
+	}
+
+	public function testAuthorizeWrongResponseType() {
+		$client = new Client();
+		$client->setClientIdentifier('MyClientIdentifier');
+		$client->setRedirectUri('http://foo.bar');
+		$this->clientMapper
+			->expects($this->once())
+			->method('getByIdentifier')
+			->with('MyClientId')
+			->willReturn($client);
+		$this->session
+			->expects($this->never())
+			->method('set');
+
+
+		$expected = new RedirectResponse('http://foo.bar?error=unsupported_response_type&state=MyState');
+		$this->assertEquals($expected, $this->loginRedirectorController->authorize('MyClientId', 'MyState', 'wrongcode'));
 	}
 }
diff --git a/apps/oauth2/tests/Controller/OauthApiControllerTest.php b/apps/oauth2/tests/Controller/OauthApiControllerTest.php
index c90e2bf711f..790dba0a598 100644
--- a/apps/oauth2/tests/Controller/OauthApiControllerTest.php
+++ b/apps/oauth2/tests/Controller/OauthApiControllerTest.php
@@ -21,12 +21,22 @@
 
 namespace OCA\OAuth2\Tests\Controller;
 
+use OC\Authentication\Exceptions\InvalidTokenException;
 use OC\Authentication\Token\DefaultToken;
 use OC\Authentication\Token\DefaultTokenMapper;
+use OC\Authentication\Token\ExpiredTokenException;
+use OC\Authentication\Token\IProvider as TokenProvider;
+use OC\Authentication\Token\IToken;
 use OCA\OAuth2\Controller\OauthApiController;
 use OCA\OAuth2\Db\AccessToken;
 use OCA\OAuth2\Db\AccessTokenMapper;
+use OCA\OAuth2\Db\Client;
+use OCA\OAuth2\Db\ClientMapper;
+use OCA\OAuth2\Exceptions\AccessTokenNotFoundException;
+use OCA\OAuth2\Exceptions\ClientNotFoundException;
+use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
+use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\IRequest;
 use OCP\Security\ICrypto;
 use OCP\Security\ISecureRandom;
@@ -39,10 +49,14 @@ class OauthApiControllerTest extends TestCase {
 	private $crypto;
 	/** @var AccessTokenMapper|\PHPUnit_Framework_MockObject_MockObject */
 	private $accessTokenMapper;
-	/** @var DefaultTokenMapper|\PHPUnit_Framework_MockObject_MockObject */
-	private $defaultTokenMapper;
+	/** @var ClientMapper|\PHPUnit_Framework_MockObject_MockObject */
+	private $clientMapper;
+	/** @var TokenProvider|\PHPUnit_Framework_MockObject_MockObject */
+	private $tokenProvider;
 	/** @var ISecureRandom|\PHPUnit_Framework_MockObject_MockObject */
 	private $secureRandom;
+	/** @var ITimeFactory|\PHPUnit_Framework_MockObject_MockObject */
+	private $time;
 	/** @var OauthApiController */
 	private $oauthApiController;
 
@@ -52,55 +66,307 @@ class OauthApiControllerTest extends TestCase {
 		$this->request = $this->createMock(IRequest::class);
 		$this->crypto = $this->createMock(ICrypto::class);
 		$this->accessTokenMapper = $this->createMock(AccessTokenMapper::class);
-		$this->defaultTokenMapper = $this->createMock(DefaultTokenMapper::class);
+		$this->clientMapper = $this->createMock(ClientMapper::class);
+		$this->tokenProvider = $this->createMock(TokenProvider::class);
 		$this->secureRandom = $this->createMock(ISecureRandom::class);
+		$this->time = $this->createMock(ITimeFactory::class);
 
 		$this->oauthApiController = new OauthApiController(
 			'oauth2',
 			$this->request,
 			$this->crypto,
 			$this->accessTokenMapper,
-			$this->defaultTokenMapper,
-			$this->secureRandom
+			$this->clientMapper,
+			$this->tokenProvider,
+			$this->secureRandom,
+			$this->time
 		);
 	}
 
-	public function testGetToken() {
+	public function testGetTokenInvalidGrantType() {
+		$expected = new JSONResponse([
+			'error' => 'invalid_grant',
+		], Http::STATUS_BAD_REQUEST);
+
+		$this->assertEquals($expected, $this->oauthApiController->getToken('foo', null, null, null, null));
+	}
+
+	public function testGetTokenInvalidCode() {
+		$expected = new JSONResponse([
+			'error' => 'invalid_request',
+		], Http::STATUS_BAD_REQUEST);
+
+		$this->accessTokenMapper->method('getByCode')
+			->with('invalidcode')
+			->willThrowException(new AccessTokenNotFoundException());
+
+		$this->assertEquals($expected, $this->oauthApiController->getToken('authorization_code', 'invalidcode', null, null, null));
+	}
+
+	public function testGetTokenInvalidRefreshToken() {
+		$expected = new JSONResponse([
+			'error' => 'invalid_request',
+		], Http::STATUS_BAD_REQUEST);
+
+		$this->accessTokenMapper->method('getByCode')
+			->with('invalidrefresh')
+			->willThrowException(new AccessTokenNotFoundException());
+
+		$this->assertEquals($expected, $this->oauthApiController->getToken('refresh_token', null, 'invalidrefresh', null, null));
+	}
+
+	public function testGetTokenClientDoesNotExist() {
+		$expected = new JSONResponse([
+			'error' => 'invalid_request',
+		], Http::STATUS_BAD_REQUEST);
+
 		$accessToken = new AccessToken();
-		$accessToken->setEncryptedToken('MyEncryptedToken');
-		$accessToken->setTokenId(123);
-		$this->accessTokenMapper
-			->expects($this->once())
-			->method('getByCode')
+		$accessToken->setClientId(42);
+
+		$this->accessTokenMapper->method('getByCode')
+			->with('validrefresh')
 			->willReturn($accessToken);
-		$this->crypto
-			->expects($this->once())
-			->method('decrypt')
-			->with('MyEncryptedToken', 'MySecretCode')
-			->willReturn('MyDecryptedToken');
-		$this->secureRandom
-			->expects($this->once())
-			->method('generate')
-			->with(128)
-			->willReturn('NewToken');
-		$token = new DefaultToken();
-		$token->setUid('JohnDoe');
-		$this->defaultTokenMapper
-			->expects($this->once())
-			->method('getTokenById')
-			->with(123)
-			->willReturn($token);
-
-		$expected = new JSONResponse(
-			[
-				'access_token' => 'MyDecryptedToken',
-				'token_type' => 'Bearer',
-				'expires_in' => 3600,
-				'refresh_token' => 'NewToken',
-				'user_id' => 'JohnDoe',
-			]
-		);
-		$this->assertEquals($expected, $this->oauthApiController->getToken('MySecretCode'));
+
+		$this->clientMapper->method('getByUid')
+			->with(42)
+			->willThrowException(new ClientNotFoundException());
+
+		$this->assertEquals($expected, $this->oauthApiController->getToken('refresh_token', null, 'validrefresh', null, null));
+	}
+
+	public function invalidClientProvider() {
+		return [
+			['invalidClientId', 'invalidClientSecret'],
+			['clientId', 'invalidClientSecret'],
+			['invalidClientId', 'clientSecret'],
+		];
+	}
+
+	/**
+	 * @dataProvider invalidClientProvider
+	 *
+	 * @param string $clientId
+	 * @param string $clientSecret
+	 */
+	public function testGetTokenInvalidClient($clientId, $clientSecret) {
+		$expected = new JSONResponse([
+			'error' => 'invalid_client',
+		], Http::STATUS_BAD_REQUEST);
+
+		$accessToken = new AccessToken();
+		$accessToken->setClientId(42);
+
+		$this->accessTokenMapper->method('getByCode')
+			->with('validrefresh')
+			->willReturn($accessToken);
+
+		$client = new Client();
+		$client->setClientIdentifier('clientId');
+		$client->setSecret('clientSecret');
+		$this->clientMapper->method('getByUid')
+			->with(42)
+			->willReturn($client);
+
+		$this->assertEquals($expected, $this->oauthApiController->getToken('refresh_token', null, 'validrefresh', $clientId, $clientSecret));
+	}
+
+	public function testGetTokenInvalidAppToken() {
+		$expected = new JSONResponse([
+			'error' => 'invalid_request',
+		], Http::STATUS_BAD_REQUEST);
+
+		$accessToken = new AccessToken();
+		$accessToken->setClientId(42);
+		$accessToken->setTokenId(1337);
+		$accessToken->setEncryptedToken('encryptedToken');
+
+		$this->accessTokenMapper->method('getByCode')
+			->with('validrefresh')
+			->willReturn($accessToken);
+
+		$client = new Client();
+		$client->setClientIdentifier('clientId');
+		$client->setSecret('clientSecret');
+		$this->clientMapper->method('getByUid')
+			->with(42)
+			->willReturn($client);
+
+		$this->crypto->method('decrypt')
+			->with(
+				'encryptedToken',
+				'validrefresh'
+			)->willReturn('decryptedToken');
+
+		$this->tokenProvider->method('getTokenById')
+			->with(1337)
+			->willThrowException(new InvalidTokenException());
+
+		$this->accessTokenMapper->expects($this->once())
+			->method('delete')
+			->with($accessToken);
+
+		$this->assertEquals($expected, $this->oauthApiController->getToken('refresh_token', null, 'validrefresh', 'clientId', 'clientSecret'));
 	}
 
+	public function testGetTokenValidAppToken() {
+		$accessToken = new AccessToken();
+		$accessToken->setClientId(42);
+		$accessToken->setTokenId(1337);
+		$accessToken->setEncryptedToken('encryptedToken');
+
+		$this->accessTokenMapper->method('getByCode')
+			->with('validrefresh')
+			->willReturn($accessToken);
+
+		$client = new Client();
+		$client->setClientIdentifier('clientId');
+		$client->setSecret('clientSecret');
+		$this->clientMapper->method('getByUid')
+			->with(42)
+			->willReturn($client);
+
+		$this->crypto->method('decrypt')
+			->with(
+				'encryptedToken',
+				'validrefresh'
+			)->willReturn('decryptedToken');
+
+		$appToken = new DefaultToken();
+		$appToken->setUid('userId');
+		$this->tokenProvider->method('getTokenById')
+			->with(1337)
+			->willThrowException(new ExpiredTokenException($appToken));
+
+		$this->accessTokenMapper->expects($this->never())
+			->method('delete')
+			->with($accessToken);
+
+		$this->secureRandom->method('generate')
+			->will($this->returnCallback(function ($len) {
+				return 'random'.$len;
+			}));
+
+		$this->tokenProvider->expects($this->once())
+			->method('rotate')
+			->with(
+				$appToken,
+				'decryptedToken',
+				'random72'
+			)->willReturn($appToken);
+
+		$this->time->method('getTime')
+			->willReturn(1000);
+
+		$this->tokenProvider->expects($this->once())
+			->method('updateToken')
+			->with(
+				$this->callback(function (DefaultToken $token) {
+					return $token->getExpires() === 4600;
+				})
+			);
+
+		$this->crypto->method('encrypt')
+			->with('random72', 'random128')
+			->willReturn('newEncryptedToken');
+
+		$this->accessTokenMapper->expects($this->once())
+			->method('update')
+			->with(
+				$this->callback(function (AccessToken $token) {
+					return $token->getHashedCode() === hash('sha512', 'random128') &&
+						$token->getEncryptedToken() === 'newEncryptedToken';
+				})
+			);
+
+		$expected = new JSONResponse([
+			'access_token' => 'random72',
+			'token_type' => 'Bearer',
+			'expires_in' => 3600,
+			'refresh_token' => 'random128',
+			'user_id' => 'userId',
+		]);
+
+		$this->assertEquals($expected, $this->oauthApiController->getToken('refresh_token', null, 'validrefresh', 'clientId', 'clientSecret'));
+	}
+
+	public function testGetTokenExpiredAppToken() {
+		$accessToken = new AccessToken();
+		$accessToken->setClientId(42);
+		$accessToken->setTokenId(1337);
+		$accessToken->setEncryptedToken('encryptedToken');
+
+		$this->accessTokenMapper->method('getByCode')
+			->with('validrefresh')
+			->willReturn($accessToken);
+
+		$client = new Client();
+		$client->setClientIdentifier('clientId');
+		$client->setSecret('clientSecret');
+		$this->clientMapper->method('getByUid')
+			->with(42)
+			->willReturn($client);
+
+		$this->crypto->method('decrypt')
+			->with(
+				'encryptedToken',
+				'validrefresh'
+			)->willReturn('decryptedToken');
+
+		$appToken = new DefaultToken();
+		$appToken->setUid('userId');
+		$this->tokenProvider->method('getTokenById')
+			->with(1337)
+			->willReturn($appToken);
+
+		$this->accessTokenMapper->expects($this->never())
+			->method('delete')
+			->with($accessToken);
+
+		$this->secureRandom->method('generate')
+			->will($this->returnCallback(function ($len) {
+				return 'random'.$len;
+			}));
+
+		$this->tokenProvider->expects($this->once())
+			->method('rotate')
+			->with(
+				$appToken,
+				'decryptedToken',
+				'random72'
+			)->willReturn($appToken);
+
+		$this->time->method('getTime')
+			->willReturn(1000);
+
+		$this->tokenProvider->expects($this->once())
+			->method('updateToken')
+			->with(
+				$this->callback(function (DefaultToken $token) {
+					return $token->getExpires() === 4600;
+				})
+			);
+
+		$this->crypto->method('encrypt')
+			->with('random72', 'random128')
+			->willReturn('newEncryptedToken');
+
+		$this->accessTokenMapper->expects($this->once())
+			->method('update')
+			->with(
+				$this->callback(function (AccessToken $token) {
+					return $token->getHashedCode() === hash('sha512', 'random128') &&
+						$token->getEncryptedToken() === 'newEncryptedToken';
+				})
+			);
+
+		$expected = new JSONResponse([
+			'access_token' => 'random72',
+			'token_type' => 'Bearer',
+			'expires_in' => 3600,
+			'refresh_token' => 'random128',
+			'user_id' => 'userId',
+		]);
+
+		$this->assertEquals($expected, $this->oauthApiController->getToken('refresh_token', null, 'validrefresh', 'clientId', 'clientSecret'));
+	}
 }
diff --git a/core/Controller/ClientFlowLoginController.php b/core/Controller/ClientFlowLoginController.php
index ab9d98df8d6..c3b88f752db 100644
--- a/core/Controller/ClientFlowLoginController.php
+++ b/core/Controller/ClientFlowLoginController.php
@@ -329,7 +329,7 @@ class ClientFlowLoginController extends Controller {
 		);
 
 		if($client) {
-			$code = $this->random->generate(128);
+			$code = $this->random->generate(128, ISecureRandom::CHAR_UPPER.ISecureRandom::CHAR_LOWER.ISecureRandom::CHAR_DIGITS);
 			$accessToken = new AccessToken();
 			$accessToken->setClientId($client->getId());
 			$accessToken->setEncryptedToken($this->crypto->encrypt($token, $code));