fix(dav): Rate limit address book creation

apps/dav/appinfo/v1/carddav.php

@@ -32,6 +32,7 @@
 use OCA\DAV\AppInfo\PluginManager;
 use OCA\DAV\CardDAV\AddressBookRoot;
 use OCA\DAV\CardDAV\CardDavBackend;
+use OCA\DAV\CardDAV\Security\CardDavRateLimitingPlugin;
 use OCA\DAV\Connector\LegacyDAVACL;
 use OCA\DAV\Connector\Sabre\Auth;
 use OCA\DAV\Connector\Sabre\ExceptionLoggerPlugin;
@@ -109,6 +110,7 @@
 	\OC::$server->get(LoggerInterface::class)
 )));
 $server->addPlugin(new ExceptionLoggerPlugin('carddav', \OC::$server->get(LoggerInterface::class)));
+$server->addPlugin(\OCP\Server::get(CardDavRateLimitingPlugin::class));
 
 // And off we go!
 $server->exec();

apps/dav/composer/composer/autoload_classmap.php

@@ -134,6 +134,7 @@
     'OCA\\DAV\\CardDAV\\MultiGetExportPlugin' => $baseDir . '/../lib/CardDAV/MultiGetExportPlugin.php',
     'OCA\\DAV\\CardDAV\\PhotoCache' => $baseDir . '/../lib/CardDAV/PhotoCache.php',
     'OCA\\DAV\\CardDAV\\Plugin' => $baseDir . '/../lib/CardDAV/Plugin.php',
+    'OCA\\DAV\\CardDAV\\Security\\CardDavRateLimitingPlugin' => $baseDir . '/../lib/CardDAV/Security/CardDavRateLimitingPlugin.php',
     'OCA\\DAV\\CardDAV\\Sharing\\Backend' => $baseDir . '/../lib/CardDAV/Sharing/Backend.php',
     'OCA\\DAV\\CardDAV\\Sharing\\Service' => $baseDir . '/../lib/CardDAV/Sharing/Service.php',
     'OCA\\DAV\\CardDAV\\SyncService' => $baseDir . '/../lib/CardDAV/SyncService.php',

apps/dav/composer/composer/autoload_static.php

@@ -155,6 +155,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\CardDAV\\SystemAddressbook' => __DIR__ . '/..' . '/../lib/CardDAV/SystemAddressbook.php',
         'OCA\\DAV\\CardDAV\\UserAddressBooks' => __DIR__ . '/..' . '/../lib/CardDAV/UserAddressBooks.php',
         'OCA\\DAV\\CardDAV\\Xml\\Groups' => __DIR__ . '/..' . '/../lib/CardDAV/Xml/Groups.php',
+        'OCA\\DAV\\CardDAV\\Security\\CardDavRateLimitingPlugin' => __DIR__ . '/..' . '/../lib/CardDAV/Security/CardDavRateLimitingPlugin.php',
         'OCA\\DAV\\Command\\CreateAddressBook' => __DIR__ . '/..' . '/../lib/Command/CreateAddressBook.php',
         'OCA\\DAV\\Command\\CreateCalendar' => __DIR__ . '/..' . '/../lib/Command/CreateCalendar.php',
         'OCA\\DAV\\Command\\DeleteCalendar' => __DIR__ . '/..' . '/../lib/Command/DeleteCalendar.php',

apps/dav/lib/CardDAV/Security/CardDavRateLimitingPlugin.php

@@ -0,0 +1,87 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * SPDX-FileCopyrightText: 2016 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\DAV\CardDAV\Security;
+
+use OC\Security\RateLimiting\Exception\RateLimitExceededException;
+use OC\Security\RateLimiting\Limiter;
+use OCA\DAV\CardDAV\CardDavBackend;
+use OCA\DAV\Connector\Sabre\Exception\TooManyRequests;
+use OCP\IAppConfig;
+use OCP\IUserManager;
+use Psr\Log\LoggerInterface;
+use Sabre\DAV;
+use Sabre\DAV\Exception\Forbidden;
+use Sabre\DAV\ServerPlugin;
+use function count;
+use function explode;
+
+class CardDavRateLimitingPlugin extends ServerPlugin {
+	private ?string $userId;
+
+	public function __construct(private Limiter $limiter,
+		private IUserManager $userManager,
+		private CardDavBackend $cardDavBackend,
+		private LoggerInterface $logger,
+		private IAppConfig $config,
+		?string $userId) {
+		$this->limiter = $limiter;
+		$this->userManager = $userManager;
+		$this->cardDavBackend = $cardDavBackend;
+		$this->config = $config;
+		$this->logger = $logger;
+		$this->userId = $userId;
+	}
+
+	public function initialize(DAV\Server $server): void {
+		$server->on('beforeBind', [$this, 'beforeBind'], 1);
+	}
+
+	public function beforeBind(string $path): void {
+		if ($this->userId === null) {
+			// We only care about authenticated users here
+			return;
+		}
+		$user = $this->userManager->get($this->userId);
+		if ($user === null) {
+			// We only care about authenticated users here
+			return;
+		}
+
+		$pathParts = explode('/', $path);
+		if (count($pathParts) === 4 && $pathParts[0] === 'addressbooks') {
+			// Path looks like addressbooks/users/username/addressbooksname so a new addressbook is created
+			try {
+				$this->limiter->registerUserRequest(
+					'carddav-create-address-book',
+					$this->config->getValueInt('dav', 'rateLimitAddressBookCreation', 10),
+					$this->config->getValueInt('dav', 'rateLimitPeriodAddressBookCreation', 3600),
+					$user
+				);
+			} catch (RateLimitExceededException $e) {
+				throw new TooManyRequests('Too many addressbooks created', 0, $e);
+			}
+
+			$addressBookLimit = $this->config->getValueInt('dav', 'maximumAdressbooks', 10);
+			if ($addressBookLimit === -1) {
+				return;
+			}
+			$numAddressbooks = $this->cardDavBackend->getAddressBooksForUserCount('principals/users/' . $user->getUID());
+
+			if ($numAddressbooks >= $addressBookLimit) {
+				$this->logger->warning('Maximum number of address books reached', [
+					'addressbooks' => $numAddressbooks,
+					'addressBookLimit' => $addressBookLimit,
+				]);
+				throw new Forbidden('AddressBook limit reached', 0);
+			}
+		}
+	}
+
+}

apps/dav/lib/Server.php

@@ -45,6 +45,7 @@
 use OCA\DAV\CardDAV\ImageExportPlugin;
 use OCA\DAV\CardDAV\MultiGetExportPlugin;
 use OCA\DAV\CardDAV\PhotoCache;
+use OCA\DAV\CardDAV\Security\CardDavRateLimitingPlugin;
 use OCA\DAV\Comments\CommentsPlugin;
 use OCA\DAV\Connector\Sabre\AnonymousOptionsPlugin;
 use OCA\DAV\Connector\Sabre\Auth;
@@ -208,6 +209,8 @@ public function __construct(IRequest $request, string $baseUri) {
 				\OC::$server->getAppDataDir('dav-photocache'),
 				$logger)
 			));
+
+			$this->server->addPlugin(\OCP\Server::get(CardDavRateLimitingPlugin::class));
 		}
 
 		// system tags plugins

apps/dav/tests/unit/CardDAV/Security/CardDavRateLimitingPluginTest.php

@@ -0,0 +1,146 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * SPDX-FileCopyrightText: 2016 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\DAV\Tests\unit\CardDAV\Security;
+
+use OC\Security\RateLimiting\Exception\RateLimitExceededException;
+use OC\Security\RateLimiting\Limiter;
+use OCA\DAV\CardDAV\CardDavBackend;
+use OCA\DAV\CardDAV\Security\CardDavRateLimitingPlugin;
+use OCA\DAV\Connector\Sabre\Exception\TooManyRequests;
+use OCP\IAppConfig;
+use OCP\IUser;
+use OCP\IUserManager;
+use PHPUnit\Framework\MockObject\MockObject;
+use Psr\Log\LoggerInterface;
+use Sabre\DAV\Exception\Forbidden;
+use Test\TestCase;
+
+class CardDavRateLimitingPluginTest extends TestCase {
+
+	private Limiter|MockObject $limiter;
+	private CardDavBackend|MockObject $cardDavBackend;
+	private IUserManager|MockObject $userManager;
+	private LoggerInterface|MockObject $logger;
+	private IAppConfig|MockObject $config;
+	private string $userId = 'user123';
+	private CardDavRateLimitingPlugin $plugin;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->limiter = $this->createMock(Limiter::class);
+		$this->userManager = $this->createMock(IUserManager::class);
+		$this->cardDavBackend = $this->createMock(CardDavBackend::class);
+		$this->logger = $this->createMock(LoggerInterface::class);
+		$this->config = $this->createMock(IAppConfig::class);
+		$this->plugin = new CardDavRateLimitingPlugin(
+			$this->limiter,
+			$this->userManager,
+			$this->cardDavBackend,
+			$this->logger,
+			$this->config,
+			$this->userId,
+		);
+	}
+
+	public function testNoUserObject(): void {
+		$this->limiter->expects(self::never())
+			->method('registerUserRequest');
+
+		$this->plugin->beforeBind('addressbooks/users/foo/addressbookname');
+	}
+
+	public function testUnrelated(): void {
+		$user = $this->createMock(IUser::class);
+		$this->userManager->expects(self::once())
+			->method('get')
+			->with($this->userId)
+			->willReturn($user);
+		$this->limiter->expects(self::never())
+			->method('registerUserRequest');
+
+		$this->plugin->beforeBind('foo/bar');
+	}
+
+	public function testRegisterAddressBookrCreation(): void {
+		$user = $this->createMock(IUser::class);
+		$this->userManager->expects(self::once())
+			->method('get')
+			->with($this->userId)
+			->willReturn($user);
+		$this->config
+			->method('getValueInt')
+			->with('dav')
+			->willReturnArgument(2);
+		$this->limiter->expects(self::once())
+			->method('registerUserRequest')
+			->with(
+				'carddav-create-address-book',
+				10,
+				3600,
+				$user,
+			);
+
+		$this->plugin->beforeBind('addressbooks/users/foo/addressbookname');
+	}
+
+	public function testAddressBookCreationRateLimitExceeded(): void {
+		$user = $this->createMock(IUser::class);
+		$this->userManager->expects(self::once())
+			->method('get')
+			->with($this->userId)
+			->willReturn($user);
+		$this->config
+			->method('getValueInt')
+			->with('dav')
+			->willReturnArgument(2);
+		$this->limiter->expects(self::once())
+			->method('registerUserRequest')
+			->with(
+				'carddav-create-address-book',
+				10,
+				3600,
+				$user,
+			)
+			->willThrowException(new RateLimitExceededException());
+		$this->expectException(TooManyRequests::class);
+
+		$this->plugin->beforeBind('addressbooks/users/foo/addressbookname');
+	}
+
+	public function testAddressBookLimitReached(): void {
+		$user = $this->createMock(IUser::class);
+		$this->userManager->expects(self::once())
+			->method('get')
+			->with($this->userId)
+			->willReturn($user);
+		$user->method('getUID')->willReturn('user123');
+		$this->config
+			->method('getValueInt')
+			->with('dav')
+			->willReturnArgument(2);
+		$this->limiter->expects(self::once())
+			->method('registerUserRequest')
+			->with(
+				'carddav-create-address-book',
+				10,
+				3600,
+				$user,
+			);
+		$this->cardDavBackend->expects(self::once())
+			->method('getAddressBooksForUserCount')
+			->with('principals/users/user123')
+			->willReturn(11);
+		$this->expectException(Forbidden::class);
+
+		$this->plugin->beforeBind('addressbooks/users/foo/addressbookname');
+	}
+
+}