fix(oauth2): retain support for legacy ownCloud clientsfix/oauth2/retain-legacy-oc-client-support

Signed-off-by: Richard Steinmetz <richard@steinmetz.cloud>

17 files changed, 264 insertions, 13 deletions

diff --git a/apps/dav/appinfo/v1/webdav.php b/apps/dav/appinfo/v1/webdav.php
index fe47ba74652..baeae66bb20 100644
--- a/apps/dav/appinfo/v1/webdav.php
+++ b/apps/dav/appinfo/v1/webdav.php
@@ -61,7 +61,8 @@ $authPlugin = new \Sabre\DAV\Auth\Plugin($authBackend);
 $bearerAuthPlugin = new BearerAuth(
 	Server::get(IUserSession::class),
 	Server::get(ISession::class),
-	Server::get(IRequest::class)
+	Server::get(IRequest::class),
+	Server::get(IConfig::class),
 );
 $authPlugin->addBackend($bearerAuthPlugin);
 
diff --git a/apps/dav/lib/Connector/Sabre/BearerAuth.php b/apps/dav/lib/Connector/Sabre/BearerAuth.php
index 07bb3e052a5..e189d8fa128 100644
--- a/apps/dav/lib/Connector/Sabre/BearerAuth.php
+++ b/apps/dav/lib/Connector/Sabre/BearerAuth.php
@@ -7,6 +7,7 @@ namespace OCA\DAV\Connector\Sabre;
 
 use OCP\AppFramework\Http;
 use OCP\Defaults;
+use OCP\IConfig;
 use OCP\IRequest;
 use OCP\ISession;
 use OCP\IUserSession;
@@ -19,6 +20,7 @@ class BearerAuth extends AbstractBearer {
 		private IUserSession $userSession,
 		private ISession $session,
 		private IRequest $request,
+		private IConfig $config,
 		private string $principalPrefix = 'principals/users/',
 	) {
 		// setup realm
@@ -57,6 +59,14 @@ class BearerAuth extends AbstractBearer {
 	 * @param ResponseInterface $response
 	 */
 	public function challenge(RequestInterface $request, ResponseInterface $response): void {
+		// Legacy ownCloud clients still authenticate via OAuth2
+		$enableOcClients = $this->config->getSystemValueBool('oauth2.enable_oc_clients', false);
+		$userAgent = $request->getHeader('User-Agent');
+		if ($enableOcClients && $userAgent !== null && str_contains($userAgent, 'mirall')) {
+			parent::challenge($request, $response);
+			return;
+		}
+
 		$response->setStatus(Http::STATUS_UNAUTHORIZED);
 	}
 }
diff --git a/apps/dav/lib/Server.php b/apps/dav/lib/Server.php
index a14b49c178e..9ea18c029c8 100644
--- a/apps/dav/lib/Server.php
+++ b/apps/dav/lib/Server.php
@@ -157,7 +157,8 @@ class Server {
 		$bearerAuthBackend = new BearerAuth(
 			\OCP\Server::get(IUserSession::class),
 			\OCP\Server::get(ISession::class),
-			\OCP\Server::get(IRequest::class)
+			\OCP\Server::get(IRequest::class),
+			\OCP\Server::get(IConfig::class),
 		);
 		$authPlugin->addBackend($bearerAuthBackend);
 		// because we are throwing exceptions this plugin has to be the last one
diff --git a/apps/dav/tests/unit/Connector/Sabre/BearerAuthTest.php b/apps/dav/tests/unit/Connector/Sabre/BearerAuthTest.php
index 06c070454af..99c2a461557 100644
--- a/apps/dav/tests/unit/Connector/Sabre/BearerAuthTest.php
+++ b/apps/dav/tests/unit/Connector/Sabre/BearerAuthTest.php
@@ -7,10 +7,12 @@ namespace OCA\DAV\Tests\unit\Connector\Sabre;
 
 use OC\User\Session;
 use OCA\DAV\Connector\Sabre\BearerAuth;
+use OCP\IConfig;
 use OCP\IRequest;
 use OCP\ISession;
 use OCP\IUser;
 use OCP\IUserSession;
+use PHPUnit\Framework\MockObject\MockObject;
 use Sabre\HTTP\RequestInterface;
 use Sabre\HTTP\ResponseInterface;
 use Test\TestCase;
@@ -28,17 +30,21 @@ class BearerAuthTest extends TestCase {
 	/** @var BearerAuth */
 	private $bearerAuth;
 
+	private IConfig&MockObject $config;
+
 	protected function setUp(): void {
 		parent::setUp();
 
 		$this->userSession = $this->createMock(Session::class);
 		$this->session = $this->createMock(ISession::class);
 		$this->request = $this->createMock(IRequest::class);
+		$this->config = $this->createMock(IConfig::class);
 
 		$this->bearerAuth = new BearerAuth(
 			$this->userSession,
 			$this->session,
-			$this->request
+			$this->request,
+			$this->config,
 		);
 	}
 
diff --git a/apps/oauth2/appinfo/info.xml b/apps/oauth2/appinfo/info.xml
index 5e4994fafa8..6ab30292ab0 100644
--- a/apps/oauth2/appinfo/info.xml
+++ b/apps/oauth2/appinfo/info.xml
@@ -33,6 +33,10 @@
 		</post-migration>
 	</repair-steps>
 
+	<commands>
+		<command>OCA\OAuth2\Command\ImportLegacyOcClient</command>
+	</commands>
+
 	<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 cba0ef43dfc..f5fc5bfe251 100644
--- a/apps/oauth2/composer/composer/autoload_classmap.php
+++ b/apps/oauth2/composer/composer/autoload_classmap.php
@@ -8,6 +8,7 @@ $baseDir = $vendorDir;
 return array(
     'Composer\\InstalledVersions' => $vendorDir . '/composer/InstalledVersions.php',
     'OCA\\OAuth2\\BackgroundJob\\CleanupExpiredAuthorizationCode' => $baseDir . '/../lib/BackgroundJob/CleanupExpiredAuthorizationCode.php',
+    'OCA\\OAuth2\\Command\\ImportLegacyOcClient' => $baseDir . '/../lib/Command/ImportLegacyOcClient.php',
     'OCA\\OAuth2\\Controller\\LoginRedirectorController' => $baseDir . '/../lib/Controller/LoginRedirectorController.php',
     'OCA\\OAuth2\\Controller\\OauthApiController' => $baseDir . '/../lib/Controller/OauthApiController.php',
     'OCA\\OAuth2\\Controller\\SettingsController' => $baseDir . '/../lib/Controller/SettingsController.php',
diff --git a/apps/oauth2/composer/composer/autoload_static.php b/apps/oauth2/composer/composer/autoload_static.php
index c4905bc96c4..c4843fa1990 100644
--- a/apps/oauth2/composer/composer/autoload_static.php
+++ b/apps/oauth2/composer/composer/autoload_static.php
@@ -23,6 +23,7 @@ class ComposerStaticInitOAuth2
     public static $classMap = array (
         'Composer\\InstalledVersions' => __DIR__ . '/..' . '/composer/InstalledVersions.php',
         'OCA\\OAuth2\\BackgroundJob\\CleanupExpiredAuthorizationCode' => __DIR__ . '/..' . '/../lib/BackgroundJob/CleanupExpiredAuthorizationCode.php',
+        'OCA\\OAuth2\\Command\\ImportLegacyOcClient' => __DIR__ . '/..' . '/../lib/Command/ImportLegacyOcClient.php',
         'OCA\\OAuth2\\Controller\\LoginRedirectorController' => __DIR__ . '/..' . '/../lib/Controller/LoginRedirectorController.php',
         'OCA\\OAuth2\\Controller\\OauthApiController' => __DIR__ . '/..' . '/../lib/Controller/OauthApiController.php',
         'OCA\\OAuth2\\Controller\\SettingsController' => __DIR__ . '/..' . '/../lib/Controller/SettingsController.php',
diff --git a/apps/oauth2/lib/Command/ImportLegacyOcClient.php b/apps/oauth2/lib/Command/ImportLegacyOcClient.php
new file mode 100644
index 00000000000..acdc57cf991
--- /dev/null
+++ b/apps/oauth2/lib/Command/ImportLegacyOcClient.php
@@ -0,0 +1,76 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\OAuth2\Command;
+
+use OCA\OAuth2\Db\Client;
+use OCA\OAuth2\Db\ClientMapper;
+use OCP\IConfig;
+use OCP\Security\ICrypto;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class ImportLegacyOcClient extends Command {
+	private const ARGUMENT_CLIENT_ID = 'client-id';
+	private const ARGUMENT_CLIENT_SECRET = 'client-secret';
+
+	public function __construct(
+		private readonly IConfig $config,
+		private readonly ICrypto $crypto,
+		private readonly ClientMapper $clientMapper,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('oauth2:import-legacy-oc-client');
+		$this->setDescription('This command is only required to be run on instances which were migrated from ownCloud without the oauth2.enable_oc_clients system config! Import a legacy Oauth2 client from an ownCloud instance and migrate it. The data is expected to be straight out of the database table oc_oauth2_clients.');
+		$this->addArgument(
+			self::ARGUMENT_CLIENT_ID,
+			InputArgument::REQUIRED,
+			'Value of the "identifier" column',
+		);
+		$this->addArgument(
+			self::ARGUMENT_CLIENT_SECRET,
+			InputArgument::REQUIRED,
+			'Value of the "secret" column',
+		);
+	}
+
+	public function isEnabled(): bool {
+		return $this->config->getSystemValueBool('oauth2.enable_oc_clients', false);
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		/** @var string $clientId */
+		$clientId = $input->getArgument(self::ARGUMENT_CLIENT_ID);
+
+		/** @var string $clientSecret */
+		$clientSecret = $input->getArgument(self::ARGUMENT_CLIENT_SECRET);
+
+		// Should not happen but just to be sure
+		if (empty($clientId) || empty($clientSecret)) {
+			return 1;
+		}
+
+		$hashedClientSecret = bin2hex($this->crypto->calculateHMAC($clientSecret));
+
+		$client = new Client();
+		$client->setName('ownCloud Desktop Client');
+		$client->setRedirectUri('http://localhost:*');
+		$client->setClientIdentifier($clientId);
+		$client->setSecret($hashedClientSecret);
+		$this->clientMapper->insert($client);
+
+		$output->writeln('<info>Client imported successfully</info>');
+		return 0;
+	}
+}
diff --git a/apps/oauth2/lib/Controller/LoginRedirectorController.php b/apps/oauth2/lib/Controller/LoginRedirectorController.php
index db233e7956e..7241b35cdcf 100644
--- a/apps/oauth2/lib/Controller/LoginRedirectorController.php
+++ b/apps/oauth2/lib/Controller/LoginRedirectorController.php
@@ -20,6 +20,7 @@ use OCP\AppFramework\Http\Attribute\UseSession;
 use OCP\AppFramework\Http\RedirectResponse;
 use OCP\AppFramework\Http\TemplateResponse;
 use OCP\IAppConfig;
+use OCP\IConfig;
 use OCP\IL10N;
 use OCP\IRequest;
 use OCP\ISession;
@@ -45,6 +46,7 @@ class LoginRedirectorController extends Controller {
 		private IL10N $l,
 		private ISecureRandom $random,
 		private IAppConfig $appConfig,
+		private IConfig $config,
 	) {
 		parent::__construct($appName, $request);
 	}
@@ -55,6 +57,7 @@ class LoginRedirectorController extends Controller {
 	 * @param string $client_id Client ID
 	 * @param string $state State of the flow
 	 * @param string $response_type Response type for the flow
+	 * @param string $redirect_uri URI to redirect to after the flow (is only used for legacy ownCloud clients)
 	 * @return TemplateResponse<Http::STATUS_OK, array{}>|RedirectResponse<Http::STATUS_SEE_OTHER, array{}>
 	 *
 	 * 200: Client not found
@@ -65,7 +68,8 @@ class LoginRedirectorController extends Controller {
 	#[UseSession]
 	public function authorize($client_id,
 		$state,
-		$response_type): TemplateResponse|RedirectResponse {
+		$response_type,
+		string $redirect_uri = ''): TemplateResponse|RedirectResponse {
 		try {
 			$client = $this->clientMapper->getByIdentifier($client_id);
 		} catch (ClientNotFoundException $e) {
@@ -81,6 +85,13 @@ class LoginRedirectorController extends Controller {
 			return new RedirectResponse($url);
 		}
 
+		$enableOcClients = $this->config->getSystemValueBool('oauth2.enable_oc_clients', false);
+
+		$providedRedirectUri = '';
+		if ($enableOcClients && $client->getRedirectUri() === 'http://localhost:*') {
+			$providedRedirectUri = $redirect_uri;
+		}
+
 		$this->session->set('oauth.state', $state);
 
 		if (in_array($client->getName(), $this->appConfig->getValueArray('oauth2', 'skipAuthPickerApplications', []))) {
@@ -95,6 +106,7 @@ class LoginRedirectorController extends Controller {
 				[
 					'stateToken' => $stateToken,
 					'clientIdentifier' => $client->getClientIdentifier(),
+					'providedRedirectUri' => $providedRedirectUri,
 				]
 			);
 		} else {
@@ -102,6 +114,7 @@ class LoginRedirectorController extends Controller {
 				'core.ClientFlowLogin.showAuthPickerPage',
 				[
 					'clientIdentifier' => $client->getClientIdentifier(),
+					'providedRedirectUri' => $providedRedirectUri,
 				]
 			);
 		}
diff --git a/apps/oauth2/openapi.json b/apps/oauth2/openapi.json
index cdf52de3f5e..76cd2da3150 100644
--- a/apps/oauth2/openapi.json
+++ b/apps/oauth2/openapi.json
@@ -65,6 +65,15 @@
                         "schema": {
                             "type": "string"
                         }
+                    },
+                    {
+                        "name": "redirect_uri",
+                        "in": "query",
+                        "description": "URI to redirect to after the flow (is only used for legacy ownCloud clients)",
+                        "schema": {
+                            "type": "string",
+                            "default": ""
+                        }
                     }
                 ],
                 "responses": {
diff --git a/apps/oauth2/tests/Controller/LoginRedirectorControllerTest.php b/apps/oauth2/tests/Controller/LoginRedirectorControllerTest.php
index afa5aae4f07..1e090665735 100644
--- a/apps/oauth2/tests/Controller/LoginRedirectorControllerTest.php
+++ b/apps/oauth2/tests/Controller/LoginRedirectorControllerTest.php
@@ -13,6 +13,7 @@ use OCA\OAuth2\Exceptions\ClientNotFoundException;
 use OCP\AppFramework\Http\RedirectResponse;
 use OCP\AppFramework\Http\TemplateResponse;
 use OCP\IAppConfig;
+use OCP\IConfig;
 use OCP\IL10N;
 use OCP\IRequest;
 use OCP\ISession;
@@ -32,6 +33,7 @@ class LoginRedirectorControllerTest extends TestCase {
 	private IL10N&MockObject $l;
 	private ISecureRandom&MockObject $random;
 	private IAppConfig&MockObject $appConfig;
+	private IConfig&MockObject $config;
 
 	private LoginRedirectorController $loginRedirectorController;
 
@@ -45,6 +47,7 @@ class LoginRedirectorControllerTest extends TestCase {
 		$this->l = $this->createMock(IL10N::class);
 		$this->random = $this->createMock(ISecureRandom::class);
 		$this->appConfig = $this->createMock(IAppConfig::class);
+		$this->config = $this->createMock(IConfig::class);
 
 		$this->loginRedirectorController = new LoginRedirectorController(
 			'oauth2',
@@ -55,6 +58,7 @@ class LoginRedirectorControllerTest extends TestCase {
 			$this->l,
 			$this->random,
 			$this->appConfig,
+			$this->config,
 		);
 	}
 
@@ -77,9 +81,15 @@ class LoginRedirectorControllerTest extends TestCase {
 				'core.ClientFlowLogin.showAuthPickerPage',
 				[
 					'clientIdentifier' => 'MyClientIdentifier',
+					'providedRedirectUri' => '',
 				]
 			)
 			->willReturn('https://example.com/?clientIdentifier=foo');
+		$this->config
+			->expects($this->once())
+			->method('getSystemValueBool')
+			->with('oauth2.enable_oc_clients', false)
+			->willReturn(false);
 
 		$expected = new RedirectResponse('https://example.com/?clientIdentifier=foo');
 		$this->assertEquals($expected, $this->loginRedirectorController->authorize('MyClientId', 'MyState', 'code'));
@@ -124,9 +134,15 @@ class LoginRedirectorControllerTest extends TestCase {
 				[
 					'stateToken' => 'MyStateToken',
 					'clientIdentifier' => 'MyClientIdentifier',
+					'providedRedirectUri' => '',
 				]
 			)
 			->willReturn('https://example.com/?clientIdentifier=foo');
+		$this->config
+			->expects($this->once())
+			->method('getSystemValueBool')
+			->with('oauth2.enable_oc_clients', false)
+			->willReturn(false);
 
 		$expected = new RedirectResponse('https://example.com/?clientIdentifier=foo');
 		$this->assertEquals($expected, $this->loginRedirectorController->authorize('MyClientId', 'MyState', 'code'));
@@ -150,6 +166,74 @@ class LoginRedirectorControllerTest extends TestCase {
 		$this->assertEquals($expected, $this->loginRedirectorController->authorize('MyClientId', 'MyState', 'wrongcode'));
 	}
 
+	public function testAuthorizeWithLegacyOcClient(): void {
+		$client = new Client();
+		$client->setClientIdentifier('MyClientIdentifier');
+		$client->setRedirectUri('http://localhost:*');
+		$this->clientMapper
+			->expects($this->once())
+			->method('getByIdentifier')
+			->with('MyClientId')
+			->willReturn($client);
+		$this->session
+			->expects($this->once())
+			->method('set')
+			->with('oauth.state', 'MyState');
+		$this->urlGenerator
+			->expects($this->once())
+			->method('linkToRouteAbsolute')
+			->with(
+				'core.ClientFlowLogin.showAuthPickerPage',
+				[
+					'clientIdentifier' => 'MyClientIdentifier',
+					'providedRedirectUri' => 'http://localhost:30000',
+				]
+			)
+			->willReturn('https://example.com/?clientIdentifier=foo&providedRedirectUri=http://localhost:30000');
+		$this->config
+			->expects($this->once())
+			->method('getSystemValueBool')
+			->with('oauth2.enable_oc_clients', false)
+			->willReturn(true);
+
+		$expected = new RedirectResponse('https://example.com/?clientIdentifier=foo&providedRedirectUri=http://localhost:30000');
+		$this->assertEquals($expected, $this->loginRedirectorController->authorize('MyClientId', 'MyState', 'code', 'http://localhost:30000'));
+	}
+
+	public function testAuthorizeNotForwardingUntrustedURIs(): void {
+		$client = new Client();
+		$client->setClientIdentifier('MyClientIdentifier');
+		$this->clientMapper
+			->expects($this->once())
+			->method('getByIdentifier')
+			->with('MyClientId')
+			->willReturn($client);
+		$this->session
+			->expects($this->once())
+			->method('set')
+			->with('oauth.state', 'MyState');
+		$this->urlGenerator
+			->expects($this->once())
+			->method('linkToRouteAbsolute')
+			->with(
+				'core.ClientFlowLogin.showAuthPickerPage',
+				[
+					'clientIdentifier' => 'MyClientIdentifier',
+					'providedRedirectUri' => '',
+				]
+			)
+			->willReturn('https://example.com/?clientIdentifier=foo');
+		$this->config
+			->expects($this->once())
+			->method('getSystemValueBool')
+			->with('oauth2.enable_oc_clients', false)
+			->willReturn(false);
+
+		$expected = new RedirectResponse('https://example.com/?clientIdentifier=foo');
+		$this->assertEquals($expected, $this->loginRedirectorController->authorize('MyClientId', 'MyState', 'code', 'http://untrusted-uri.com'));
+	}
+
+
 	public function testClientNotFound(): void {
 		$clientNotFound = new ClientNotFoundException('could not find client test123', 0);
 		$this->clientMapper
diff --git a/core/Controller/ClientFlowLoginController.php b/core/Controller/ClientFlowLoginController.php
index 8d84ac100fa..99074e6ff59 100644
--- a/core/Controller/ClientFlowLoginController.php
+++ b/core/Controller/ClientFlowLoginController.php
@@ -26,6 +26,7 @@ use OCP\Authentication\Exceptions\InvalidTokenException;
 use OCP\Authentication\Token\IToken;
 use OCP\Defaults;
 use OCP\EventDispatcher\IEventDispatcher;
+use OCP\IConfig;
 use OCP\IL10N;
 use OCP\IRequest;
 use OCP\ISession;
@@ -55,6 +56,7 @@ class ClientFlowLoginController extends Controller {
 		private ICrypto $crypto,
 		private IEventDispatcher $eventDispatcher,
 		private ITimeFactory $timeFactory,
+		private IConfig $config,
 	) {
 		parent::__construct($appName, $request);
 	}
@@ -89,7 +91,7 @@ class ClientFlowLoginController extends Controller {
 	#[NoCSRFRequired]
 	#[UseSession]
 	#[FrontpageRoute(verb: 'GET', url: '/login/flow')]
-	public function showAuthPickerPage(string $clientIdentifier = '', string $user = '', int $direct = 0): StandaloneTemplateResponse {
+	public function showAuthPickerPage(string $clientIdentifier = '', string $user = '', int $direct = 0, string $providedRedirectUri = ''): StandaloneTemplateResponse {
 		$clientName = $this->getClientName();
 		$client = null;
 		if ($clientIdentifier !== '') {
@@ -142,6 +144,7 @@ class ClientFlowLoginController extends Controller {
 				'oauthState' => $this->session->get('oauth.state'),
 				'user' => $user,
 				'direct' => $direct,
+				'providedRedirectUri' => $providedRedirectUri,
 			],
 			'guest'
 		);
@@ -161,6 +164,7 @@ class ClientFlowLoginController extends Controller {
 		string $stateToken = '',
 		string $clientIdentifier = '',
 		int $direct = 0,
+		string $providedRedirectUri = '',
 	): Response {
 		if (!$this->isValidToken($stateToken)) {
 			return $this->stateTokenForbiddenResponse();
@@ -197,6 +201,7 @@ class ClientFlowLoginController extends Controller {
 				'serverHost' => $this->getServerPath(),
 				'oauthState' => $this->session->get('oauth.state'),
 				'direct' => $direct,
+				'providedRedirectUri' => $providedRedirectUri,
 			],
 			'guest'
 		);
@@ -211,6 +216,7 @@ class ClientFlowLoginController extends Controller {
 	public function generateAppPassword(
 		string $stateToken,
 		string $clientIdentifier = '',
+		string $providedRedirectUri = '',
 	): Response {
 		if (!$this->isValidToken($stateToken)) {
 			$this->session->remove(self::STATE_NAME);
@@ -270,7 +276,19 @@ class ClientFlowLoginController extends Controller {
 			$accessToken->setCodeCreatedAt($this->timeFactory->now()->getTimestamp());
 			$this->accessTokenMapper->insert($accessToken);
 
+			$enableOcClients = $this->config->getSystemValueBool('oauth2.enable_oc_clients', false);
+
 			$redirectUri = $client->getRedirectUri();
+			if ($enableOcClients && $redirectUri === 'http://localhost:*') {
+				// Sanity check untrusted redirect URI provided by the client first
+				if (!preg_match('/^http:\/\/localhost:[0-9]+$/', $providedRedirectUri)) {
+					$response = new Response();
+					$response->setStatus(Http::STATUS_FORBIDDEN);
+					return $response;
+				}
+
+				$redirectUri = $providedRedirectUri;
+			}
 
 			if (parse_url($redirectUri, PHP_URL_QUERY)) {
 				$redirectUri .= '&';
diff --git a/core/templates/loginflow/authpicker.php b/core/templates/loginflow/authpicker.php
index 94aace60cba..47e3113604d 100644
--- a/core/templates/loginflow/authpicker.php
+++ b/core/templates/loginflow/authpicker.php
@@ -31,7 +31,7 @@ $urlGenerator = $_['urlGenerator'];
 	<br/>
 
 	<p id="redirect-link">
-		<form id="login-form" action="<?php p($urlGenerator->linkToRoute('core.ClientFlowLogin.grantPage', ['stateToken' => $_['stateToken'], 'clientIdentifier' => $_['clientIdentifier'], 'oauthState' => $_['oauthState'], 'user' => $_['user'], 'direct' => $_['direct']])) ?>" method="get">
+		<form id="login-form" action="<?php p($urlGenerator->linkToRoute('core.ClientFlowLogin.grantPage', ['stateToken' => $_['stateToken'], 'clientIdentifier' => $_['clientIdentifier'], 'oauthState' => $_['oauthState'], 'user' => $_['user'], 'direct' => $_['direct'], 'providedRedirectUri' => $_['providedRedirectUri']])) ?>" method="get">
 			<input type="submit" class="login primary icon-confirm-white" value="<?php p($l->t('Log in')) ?>" disabled>
 		</form>
 	</p>
diff --git a/core/templates/loginflow/grant.php b/core/templates/loginflow/grant.php
index dd2fb8d1a8e..6beafccc96e 100644
--- a/core/templates/loginflow/grant.php
+++ b/core/templates/loginflow/grant.php
@@ -35,6 +35,7 @@ $urlGenerator = $_['urlGenerator'];
 			<input type="hidden" name="requesttoken" value="<?php p($_['requesttoken']) ?>" />
 			<input type="hidden" name="stateToken" value="<?php p($_['stateToken']) ?>" />
 			<input type="hidden" name="oauthState" value="<?php p($_['oauthState']) ?>" />
+			<input type="hidden" name="providedRedirectUri" value="<?php p($_['providedRedirectUri']) ?>">
 			<?php if ($_['direct']) { ?>
 			<input type="hidden" name="direct" value="1" />
 			<?php } ?>
diff --git a/lib/private/Repair/Owncloud/MigrateOauthTables.php b/lib/private/Repair/Owncloud/MigrateOauthTables.php
index cd5087cb588..de26a907e02 100644
--- a/lib/private/Repair/Owncloud/MigrateOauthTables.php
+++ b/lib/private/Repair/Owncloud/MigrateOauthTables.php
@@ -15,6 +15,7 @@ use OCA\OAuth2\Db\AccessTokenMapper;
 use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\Authentication\Token\IToken;
 use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\IConfig;
 use OCP\Migration\IOutput;
 use OCP\Migration\IRepairStep;
 use OCP\Security\ICrypto;
@@ -29,6 +30,7 @@ class MigrateOauthTables implements IRepairStep {
 		private ISecureRandom $random,
 		private ITimeFactory $timeFactory,
 		private ICrypto $crypto,
+		private IConfig $config,
 	) {
 	}
 
@@ -169,7 +171,12 @@ class MigrateOauthTables implements IRepairStep {
 			$schema = new SchemaWrapper($this->db);
 		}
 
-		$output->info('Delete clients (and their related access tokens) with the redirect_uri starting with oc:// or ending with *');
+		$enableOcClients = $this->config->getSystemValueBool('oauth2.enable_oc_clients', false);
+		if ($enableOcClients) {
+			$output->info('Delete clients (and their related access tokens) with the redirect_uri starting with oc://');
+		} else {
+			$output->info('Delete clients (and their related access tokens) with the redirect_uri starting with oc:// or ending with *');
+		}
 		// delete the access tokens
 		$qbDeleteAccessTokens = $this->db->getQueryBuilder();
 
@@ -178,10 +185,12 @@ class MigrateOauthTables implements IRepairStep {
 			->from('oauth2_clients')
 			->where(
 				$qbSelectClientId->expr()->iLike('redirect_uri', $qbDeleteAccessTokens->createNamedParameter('oc://%', IQueryBuilder::PARAM_STR))
-			)
-			->orWhere(
+			);
+		if (!$enableOcClients) {
+			$qbSelectClientId->orWhere(
 				$qbSelectClientId->expr()->iLike('redirect_uri', $qbDeleteAccessTokens->createNamedParameter('%*', IQueryBuilder::PARAM_STR))
 			);
+		}
 
 		$qbDeleteAccessTokens->delete('oauth2_access_tokens')
 			->where(
@@ -194,10 +203,12 @@ class MigrateOauthTables implements IRepairStep {
 		$qbDeleteClients->delete('oauth2_clients')
 			->where(
 				$qbDeleteClients->expr()->iLike('redirect_uri', $qbDeleteClients->createNamedParameter('oc://%', IQueryBuilder::PARAM_STR))
-			)
-			->orWhere(
+			);
+		if (!$enableOcClients) {
+			$qbDeleteClients->orWhere(
 				$qbDeleteClients->expr()->iLike('redirect_uri', $qbDeleteClients->createNamedParameter('%*', IQueryBuilder::PARAM_STR))
 			);
+		}
 		$qbDeleteClients->executeStatement();
 
 		// Migrate legacy refresh tokens from oc
diff --git a/openapi.json b/openapi.json
index a82c05fd331..c7ca00d5157 100644
--- a/openapi.json
+++ b/openapi.json
@@ -22147,6 +22147,15 @@
                         "schema": {
                             "type": "string"
                         }
+                    },
+                    {
+                        "name": "redirect_uri",
+                        "in": "query",
+                        "description": "URI to redirect to after the flow (is only used for legacy ownCloud clients)",
+                        "schema": {
+                            "type": "string",
+                            "default": ""
+                        }
                     }
                 ],
                 "responses": {
diff --git a/tests/Core/Controller/ClientFlowLoginControllerTest.php b/tests/Core/Controller/ClientFlowLoginControllerTest.php
index 1f4575208b8..591a3027e96 100644
--- a/tests/Core/Controller/ClientFlowLoginControllerTest.php
+++ b/tests/Core/Controller/ClientFlowLoginControllerTest.php
@@ -22,6 +22,7 @@ use OCP\AppFramework\Http\StandaloneTemplateResponse;
 use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\Defaults;
 use OCP\EventDispatcher\IEventDispatcher;
+use OCP\IConfig;
 use OCP\IL10N;
 use OCP\IRequest;
 use OCP\ISession;
@@ -48,6 +49,7 @@ class ClientFlowLoginControllerTest extends TestCase {
 	private ICrypto&MockObject $crypto;
 	private IEventDispatcher&MockObject $eventDispatcher;
 	private ITimeFactory&MockObject $timeFactory;
+	private IConfig&MockObject $config;
 
 	private ClientFlowLoginController $clientFlowLoginController;
 
@@ -73,6 +75,7 @@ class ClientFlowLoginControllerTest extends TestCase {
 		$this->crypto = $this->createMock(ICrypto::class);
 		$this->eventDispatcher = $this->createMock(IEventDispatcher::class);
 		$this->timeFactory = $this->createMock(ITimeFactory::class);
+		$this->config = $this->createMock(IConfig::class);
 
 		$this->clientFlowLoginController = new ClientFlowLoginController(
 			'core',
@@ -89,6 +92,7 @@ class ClientFlowLoginControllerTest extends TestCase {
 			$this->crypto,
 			$this->eventDispatcher,
 			$this->timeFactory,
+			$this->config,
 		);
 	}
 
@@ -163,7 +167,8 @@ class ClientFlowLoginControllerTest extends TestCase {
 				'serverHost' => 'https://example.com',
 				'oauthState' => 'OauthStateToken',
 				'user' => '',
-				'direct' => 0
+				'direct' => 0,
+				'providedRedirectUri' => '',
 			],
 			'guest'
 		);
@@ -233,7 +238,8 @@ class ClientFlowLoginControllerTest extends TestCase {
 				'serverHost' => 'https://example.com',
 				'oauthState' => 'OauthStateToken',
 				'user' => '',
-				'direct' => 0
+				'direct' => 0,
+				'providedRedirectUri' => '',
 			],
 			'guest'
 		);