fix(auth): confine OCM access token to the masked share endpoint

apps/dav/appinfo/v1/caldav.php

@@ -18,7 +18,6 @@
 use OCA\DAV\CalDAV\Validation\CalDavValidatePlugin;
 use OCA\DAV\Connector\LegacyDAVACL;
 use OCA\DAV\Connector\Sabre\Auth;
-use OCA\DAV\Connector\Sabre\BearerAuth;
 use OCA\DAV\Connector\Sabre\ExceptionLoggerPlugin;
 use OCA\DAV\Connector\Sabre\MaintenancePlugin;
 use OCA\DAV\Connector\Sabre\Principal;
@@ -48,12 +47,6 @@
 	Server::get(IThrottler::class),
 	'principals/'
 );
-$bearerAuthBackend = new BearerAuth(
-	Server::get(IUserSession::class),
-	Server::get(ISession::class),
-	Server::get(IRequest::class),
-	Server::get(IConfig::class),
-);
 $principalBackend = new Principal(
 	Server::get(IUserManager::class),
 	Server::get(IGroupManager::class),
@@ -115,9 +108,7 @@
 
 // Add plugins
 $server->addPlugin(new MaintenancePlugin(Server::get(IConfig::class), $davL10n));
-$authPlugin = new \Sabre\DAV\Auth\Plugin($authBackend);
-$authPlugin->addBackend($bearerAuthBackend);
-$server->addPlugin($authPlugin);
+$server->addPlugin(new \Sabre\DAV\Auth\Plugin($authBackend));
 $server->addPlugin(new \Sabre\CalDAV\Plugin());
 
 $server->addPlugin(new LegacyDAVACL());

apps/dav/appinfo/v1/carddav.php

@@ -17,7 +17,6 @@
 use OCA\DAV\CardDAV\Validation\CardDavValidatePlugin;
 use OCA\DAV\Connector\LegacyDAVACL;
 use OCA\DAV\Connector\Sabre\Auth;
-use OCA\DAV\Connector\Sabre\BearerAuth;
 use OCA\DAV\Connector\Sabre\ExceptionLoggerPlugin;
 use OCA\DAV\Connector\Sabre\MaintenancePlugin;
 use OCA\DAV\Connector\Sabre\Principal;
@@ -45,12 +44,6 @@
 	Server::get(IThrottler::class),
 	'principals/'
 );
-$bearerAuthBackend = new BearerAuth(
-	Server::get(IUserSession::class),
-	Server::get(ISession::class),
-	Server::get(IRequest::class),
-	Server::get(IConfig::class),
-);
 $principalBackend = new Principal(
 	Server::get(IUserManager::class),
 	Server::get(IGroupManager::class),
@@ -97,9 +90,7 @@
 $server->setBaseUri($baseuri);
 // Add plugins
 $server->addPlugin(new MaintenancePlugin(Server::get(IConfig::class), Server::get(IL10nFactory::class)->get('dav')));
-$authPlugin = new \Sabre\DAV\Auth\Plugin($authBackend);
-$authPlugin->addBackend($bearerAuthBackend);
-$server->addPlugin($authPlugin);
+$server->addPlugin(new \Sabre\DAV\Auth\Plugin($authBackend));
 $server->addPlugin(new Plugin());
 
 $server->addPlugin(new LegacyDAVACL());

apps/dav/appinfo/v1/publicwebdav.php

@@ -56,6 +56,7 @@
 	Server::get(ISession::class),
 	Server::get(IRequest::class),
 	Server::get(IConfig::class),
+	allowOcmAccessToken: true,
 );
 $authPlugin = new \Sabre\DAV\Auth\Plugin($authBackend);
 $authPlugin->addBackend($bearerAuthBackend);

apps/dav/appinfo/v2/publicremote.php

@@ -74,6 +74,7 @@
 	$session,
 	$request,
 	Server::get(IConfig::class),
+	allowOcmAccessToken: true,
 );
 $authPlugin = new \Sabre\DAV\Auth\Plugin($authBackend);
 $authPlugin->addBackend($bearerAuthBackend);

apps/dav/lib/Connector/Sabre/BearerAuth.php

@@ -28,6 +28,7 @@ public function __construct(
 		private IConfig $config,
 		private string $principalPrefix = 'principals/users/',
 		private string $token = '',
+		private bool $allowOcmAccessToken = false,
 	) {
 		// setup realm
 		$defaults = new Defaults();
@@ -57,7 +58,7 @@ public function validateBearerToken($bearerToken) {
 		\OC_User::setIncognitoMode(false);
 
 		if (!$this->userSession->isLoggedIn()) {
-			$this->userSession->tryTokenLogin($this->request);
+			$this->userSession->tryTokenLogin($this->request, $this->allowOcmAccessToken);
 		}
 		if ($this->userSession->isLoggedIn()) {
 			return $this->setupUserFs($this->userSession->getUser()->getUID());

apps/dav/tests/unit/Connector/Sabre/BearerAuthTest.php

@@ -70,6 +70,40 @@ public function testValidateBearerToken(): void {
 		$this->assertSame('principals/users/admin', $this->bearerAuth->validateBearerToken('Token'));
 	}
 
+	public function testValidateBearerTokenDefaultsOcmFlagToFalse(): void {
+		$this->userSession
+			->method('isLoggedIn')
+			->willReturnOnConsecutiveCalls(false, false);
+		$this->userSession
+			->expects($this->once())
+			->method('tryTokenLogin')
+			->with($this->request, false);
+
+		$this->assertFalse($this->bearerAuth->validateBearerToken('Token'));
+	}
+
+	public function testValidateBearerTokenPassesOcmFlagWhenAllowed(): void {
+		$bearerAuth = new BearerAuth(
+			$this->userSession,
+			$this->session,
+			$this->request,
+			$this->config,
+			allowOcmAccessToken: true,
+		);
+		$this->userSession
+			->method('isLoggedIn')
+			->willReturnOnConsecutiveCalls(false, true);
+		$this->userSession
+			->expects($this->once())
+			->method('tryTokenLogin')
+			->with($this->request, true);
+		$user = $this->createMock(IUser::class);
+		$user->method('getUID')->willReturn('admin');
+		$this->userSession->method('getUser')->willReturn($user);
+
+		$this->assertSame('principals/users/admin', $bearerAuth->validateBearerToken('Token'));
+	}
+
 	public function testChallenge(): void {
 		/** @var RequestInterface&MockObject $request */
 		$request = $this->createMock(RequestInterface::class);

lib/private/User/Session.php

@@ -816,10 +816,13 @@ private function validateTokenLoginName(?string $loginName, IToken $token): bool
 	 * Tries to login the user with auth token header
 	 *
 	 * @param IRequest $request
+	 * @param bool $allowOcmAccessToken Whether an OCM access token may log in
+	 *                                  from a Bearer header. Only the masked
+	 *                                  public share endpoints may set this.
 	 * @todo check remember me cookie
 	 * @return boolean
 	 */
-	public function tryTokenLogin(IRequest $request) {
+	public function tryTokenLogin(IRequest $request, bool $allowOcmAccessToken = false) {
 		$authHeader = $request->getHeader('Authorization');
 		$tokenFromCookie = false;
 		if (str_starts_with($authHeader, 'Bearer ')) {
@@ -847,7 +850,7 @@ public function tryTokenLogin(IRequest $request) {
 		if ($dbToken instanceof PublicKeyToken
 			&& $dbToken->getType() === IToken::TEMPORARY_TOKEN
 			&& !$tokenFromCookie
-			&& $dbToken->getName() !== IToken::OCM_ACCESS_TOKEN_NAME) {
+			&& !($allowOcmAccessToken && $dbToken->getName() === IToken::OCM_ACCESS_TOKEN_NAME)) {
 			// Session token but from Bearer header, not allowed
 			return false;
 		}

tests/lib/User/SessionTest.php

@@ -662,6 +662,59 @@ public function testTryTokenLoginNotAnAppPassword(): void {
 		self::assertTrue($loginResult);
 	}
 
+	public function testTryTokenLoginOcmAccessTokenRejectedFromBearerByDefault(): void {
+		$request = $this->createMock(IRequest::class);
+		$request->method('getHeader')->with('Authorization')->willReturn('Bearer ocm-access-token');
+		$dbToken = new PublicKeyToken();
+		$dbToken->setId(42);
+		$dbToken->setUid('alice');
+		$dbToken->setLoginName('alice');
+		$dbToken->setLastCheck(0);
+		$dbToken->setType(IToken::TEMPORARY_TOKEN);
+		$dbToken->setName(IToken::OCM_ACCESS_TOKEN_NAME);
+		$this->tokenProvider->expects(self::once())
+			->method('getToken')
+			->with('ocm-access-token')
+			->willReturn($dbToken);
+		// The guard must reject before any login is attempted.
+		$this->manager->expects(self::never())
+			->method('get');
+
+		$loginResult = $this->userSession->tryTokenLogin($request);
+
+		self::assertFalse($loginResult);
+	}
+
+	public function testTryTokenLoginOcmAccessTokenAllowedFromBearerWhenPermitted(): void {
+		$request = $this->createMock(IRequest::class);
+		$request->method('getHeader')->with('Authorization')->willReturn('Bearer ocm-access-token');
+		$dbToken = new PublicKeyToken();
+		$dbToken->setId(42);
+		$dbToken->setUid('alice');
+		$dbToken->setLoginName('alice');
+		$dbToken->setLastCheck(0);
+		$dbToken->setType(IToken::TEMPORARY_TOKEN);
+		$dbToken->setName(IToken::OCM_ACCESS_TOKEN_NAME);
+		$this->tokenProvider->method('getToken')
+			->with('ocm-access-token')
+			->willReturn($dbToken);
+		$this->session->method('set')
+			->willReturnCallback(function ($key, $value): void {
+				if ($key === 'app_password') {
+					throw new ExpectationFailedException('app_password should not be set in session');
+				}
+			});
+		$user = $this->createMock(IUser::class);
+		$user->method('isEnabled')->willReturn(true);
+		$this->manager->method('get')
+			->with('alice')
+			->willReturn($user);
+
+		$loginResult = $this->userSession->tryTokenLogin($request, true);
+
+		self::assertTrue($loginResult);
+	}
+
 	public function testRememberLoginValidToken(): void {
 		$session = $this->createMock(Memory::class);
 		$managerMethods = get_class_methods(Manager::class);