Merge pull request #28728 from nextcloud/add-database-backend-limiter

Add database ratelimiting backend

7 files changed, 158 insertions, 30 deletions

diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index 3f1f0d3b336..caddb528d5a 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -971,6 +971,7 @@ return array(
     'OC\\Core\\Migrations\\Version21000Date20210309185126' => $baseDir . '/core/Migrations/Version21000Date20210309185126.php',
     'OC\\Core\\Migrations\\Version21000Date20210309185127' => $baseDir . '/core/Migrations/Version21000Date20210309185127.php',
     'OC\\Core\\Migrations\\Version22000Date20210216080825' => $baseDir . '/core/Migrations/Version22000Date20210216080825.php',
+    'OC\\Core\\Migrations\\Version23000Date20210906132259' => $baseDir . '/core/Migrations/Version23000Date20210906132259.php',
     'OC\\Core\\Notification\\CoreNotifier' => $baseDir . '/core/Notification/CoreNotifier.php',
     'OC\\Core\\Service\\LoginFlowV2Service' => $baseDir . '/core/Service/LoginFlowV2Service.php',
     'OC\\DB\\Adapter' => $baseDir . '/lib/private/DB/Adapter.php',
@@ -1367,8 +1368,9 @@ return array(
     'OC\\Security\\IdentityProof\\Manager' => $baseDir . '/lib/private/Security/IdentityProof/Manager.php',
     'OC\\Security\\IdentityProof\\Signer' => $baseDir . '/lib/private/Security/IdentityProof/Signer.php',
     'OC\\Security\\Normalizer\\IpAddress' => $baseDir . '/lib/private/Security/Normalizer/IpAddress.php',
+    'OC\\Security\\RateLimiting\\Backend\\DatabaseBackend' => $baseDir . '/lib/private/Security/RateLimiting/Backend/DatabaseBackend.php',
     'OC\\Security\\RateLimiting\\Backend\\IBackend' => $baseDir . '/lib/private/Security/RateLimiting/Backend/IBackend.php',
-    'OC\\Security\\RateLimiting\\Backend\\MemoryCache' => $baseDir . '/lib/private/Security/RateLimiting/Backend/MemoryCache.php',
+    'OC\\Security\\RateLimiting\\Backend\\MemoryCacheBackend' => $baseDir . '/lib/private/Security/RateLimiting/Backend/MemoryCacheBackend.php',
     'OC\\Security\\RateLimiting\\Exception\\RateLimitExceededException' => $baseDir . '/lib/private/Security/RateLimiting/Exception/RateLimitExceededException.php',
     'OC\\Security\\RateLimiting\\Limiter' => $baseDir . '/lib/private/Security/RateLimiting/Limiter.php',
     'OC\\Security\\SecureRandom' => $baseDir . '/lib/private/Security/SecureRandom.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index a5b624e6e6c..727fe0fc956 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -1000,6 +1000,7 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OC\\Core\\Migrations\\Version21000Date20210309185126' => __DIR__ . '/../../..' . '/core/Migrations/Version21000Date20210309185126.php',
         'OC\\Core\\Migrations\\Version21000Date20210309185127' => __DIR__ . '/../../..' . '/core/Migrations/Version21000Date20210309185127.php',
         'OC\\Core\\Migrations\\Version22000Date20210216080825' => __DIR__ . '/../../..' . '/core/Migrations/Version22000Date20210216080825.php',
+        'OC\\Core\\Migrations\\Version23000Date20210906132259' => __DIR__ . '/../../..' . '/core/Migrations/Version23000Date20210906132259.php',
         'OC\\Core\\Notification\\CoreNotifier' => __DIR__ . '/../../..' . '/core/Notification/CoreNotifier.php',
         'OC\\Core\\Service\\LoginFlowV2Service' => __DIR__ . '/../../..' . '/core/Service/LoginFlowV2Service.php',
         'OC\\DB\\Adapter' => __DIR__ . '/../../..' . '/lib/private/DB/Adapter.php',
@@ -1396,8 +1397,9 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OC\\Security\\IdentityProof\\Manager' => __DIR__ . '/../../..' . '/lib/private/Security/IdentityProof/Manager.php',
         'OC\\Security\\IdentityProof\\Signer' => __DIR__ . '/../../..' . '/lib/private/Security/IdentityProof/Signer.php',
         'OC\\Security\\Normalizer\\IpAddress' => __DIR__ . '/../../..' . '/lib/private/Security/Normalizer/IpAddress.php',
+        'OC\\Security\\RateLimiting\\Backend\\DatabaseBackend' => __DIR__ . '/../../..' . '/lib/private/Security/RateLimiting/Backend/DatabaseBackend.php',
         'OC\\Security\\RateLimiting\\Backend\\IBackend' => __DIR__ . '/../../..' . '/lib/private/Security/RateLimiting/Backend/IBackend.php',
-        'OC\\Security\\RateLimiting\\Backend\\MemoryCache' => __DIR__ . '/../../..' . '/lib/private/Security/RateLimiting/Backend/MemoryCache.php',
+        'OC\\Security\\RateLimiting\\Backend\\MemoryCacheBackend' => __DIR__ . '/../../..' . '/lib/private/Security/RateLimiting/Backend/MemoryCacheBackend.php',
         'OC\\Security\\RateLimiting\\Exception\\RateLimitExceededException' => __DIR__ . '/../../..' . '/lib/private/Security/RateLimiting/Exception/RateLimitExceededException.php',
         'OC\\Security\\RateLimiting\\Limiter' => __DIR__ . '/../../..' . '/lib/private/Security/RateLimiting/Limiter.php',
         'OC\\Security\\SecureRandom' => __DIR__ . '/../../..' . '/lib/private/Security/SecureRandom.php',
diff --git a/lib/private/Security/RateLimiting/Backend/DatabaseBackend.php b/lib/private/Security/RateLimiting/Backend/DatabaseBackend.php
new file mode 100644
index 00000000000..1415b5c4131
--- /dev/null
+++ b/lib/private/Security/RateLimiting/Backend/DatabaseBackend.php
@@ -0,0 +1,124 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2021 Lukas Reschke <lukas@statuscode.ch>
+ *
+ * @author Lukas Reschke <lukas@statuscode.ch>
+ *
+ * @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 OC\Security\RateLimiting\Backend;
+
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\IDBConnection;
+
+class DatabaseBackend implements IBackend {
+	private const TABLE_NAME = 'ratelimit_entries';
+
+	/** @var IDBConnection */
+	private $dbConnection;
+	/** @var ITimeFactory */
+	private $timeFactory;
+
+	/**
+	 * @param IDBConnection $dbConnection
+	 * @param ITimeFactory $timeFactory
+	 */
+	public function __construct(
+		IDBConnection $dbConnection,
+		ITimeFactory $timeFactory
+	) {
+		$this->dbConnection = $dbConnection;
+		$this->timeFactory = $timeFactory;
+	}
+
+	/**
+	 * @param string $methodIdentifier
+	 * @param string $userIdentifier
+	 * @return string
+	 */
+	private function hash(string $methodIdentifier,
+						  string $userIdentifier): string {
+		return hash('sha512', $methodIdentifier . $userIdentifier);
+	}
+
+	/**
+	 * @param string $identifier
+	 * @param int $seconds
+	 * @return int
+	 * @throws \OCP\DB\Exception
+	 */
+	private function getExistingAttemptCount(
+		string $identifier
+	): int {
+		$currentTime = $this->timeFactory->getDateTime();
+
+		$qb = $this->dbConnection->getQueryBuilder();
+		$qb->delete(self::TABLE_NAME)
+			->where(
+				$qb->expr()->lte('delete_after', $qb->createNamedParameter($currentTime, IQueryBuilder::PARAM_DATE))
+			)
+			->executeStatement();
+
+		$qb = $this->dbConnection->getQueryBuilder();
+		$qb->select($qb->func()->count())
+			->from(self::TABLE_NAME)
+			->where(
+				$qb->expr()->eq('hash', $qb->createNamedParameter($identifier, IQueryBuilder::PARAM_STR))
+			)
+			->andWhere(
+				$qb->expr()->gte('delete_after', $qb->createNamedParameter($currentTime, IQueryBuilder::PARAM_DATE))
+			);
+
+		$cursor = $qb->executeQuery();
+		$row = $cursor->fetchOne();
+		$cursor->closeCursor();
+
+		return (int)$row;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	public function getAttempts(string $methodIdentifier,
+								string $userIdentifier): int {
+		$identifier = $this->hash($methodIdentifier, $userIdentifier);
+		return $this->getExistingAttemptCount($identifier);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	public function registerAttempt(string $methodIdentifier,
+									string $userIdentifier,
+									int $period) {
+		$identifier = $this->hash($methodIdentifier, $userIdentifier);
+		$deleteAfter = $this->timeFactory->getDateTime()->add(new \DateInterval("PT{$period}S"));
+
+		$qb = $this->dbConnection->getQueryBuilder();
+
+		$qb->insert(self::TABLE_NAME)
+			->values([
+				'hash' => $qb->createNamedParameter($identifier, IQueryBuilder::PARAM_STR),
+				'delete_after' => $qb->createNamedParameter($deleteAfter, IQueryBuilder::PARAM_DATE),
+			])
+			->executeStatement();
+	}
+}
diff --git a/lib/private/Security/RateLimiting/Backend/IBackend.php b/lib/private/Security/RateLimiting/Backend/IBackend.php
index d87f53311b2..960bfd2d159 100644
--- a/lib/private/Security/RateLimiting/Backend/IBackend.php
+++ b/lib/private/Security/RateLimiting/Backend/IBackend.php
@@ -35,16 +35,14 @@ namespace OC\Security\RateLimiting\Backend;
  */
 interface IBackend {
 	/**
-	 * Gets the amount of attempts within the last specified seconds
+	 * Gets the number of attempts for the specified method
 	 *
 	 * @param string $methodIdentifier Identifier for the method
 	 * @param string $userIdentifier Identifier for the user
-	 * @param int $seconds Seconds to look back at
 	 * @return int
 	 */
 	public function getAttempts(string $methodIdentifier,
-								string $userIdentifier,
-								int $seconds): int;
+								string $userIdentifier): int;
 
 	/**
 	 * Registers an attempt
diff --git a/lib/private/Security/RateLimiting/Backend/MemoryCache.php b/lib/private/Security/RateLimiting/Backend/MemoryCacheBackend.php
index 0dab25e4048..f4880fb239c 100644
--- a/lib/private/Security/RateLimiting/Backend/MemoryCache.php
+++ b/lib/private/Security/RateLimiting/Backend/MemoryCacheBackend.php
@@ -33,12 +33,12 @@ use OCP\ICache;
 use OCP\ICacheFactory;
 
 /**
- * Class MemoryCache uses the configured distributed memory cache for storing
+ * Class MemoryCacheBackend uses the configured distributed memory cache for storing
  * rate limiting data.
  *
  * @package OC\Security\RateLimiting\Backend
  */
-class MemoryCache implements IBackend {
+class MemoryCacheBackend implements IBackend {
 	/** @var ICache */
 	private $cache;
 	/** @var ITimeFactory */
@@ -86,16 +86,14 @@ class MemoryCache implements IBackend {
 	 * {@inheritDoc}
 	 */
 	public function getAttempts(string $methodIdentifier,
-								string $userIdentifier,
-								int $seconds): int {
+								string $userIdentifier): int {
 		$identifier = $this->hash($methodIdentifier, $userIdentifier);
 		$existingAttempts = $this->getExistingAttempts($identifier);
 
 		$count = 0;
 		$currentTime = $this->timeFactory->getTime();
-		/** @var array $existingAttempts */
-		foreach ($existingAttempts as $attempt) {
-			if (($attempt + $seconds) > $currentTime) {
+		foreach ($existingAttempts as $expirationTime) {
+			if ($expirationTime > $currentTime) {
 				$count++;
 			}
 		}
@@ -113,16 +111,16 @@ class MemoryCache implements IBackend {
 		$existingAttempts = $this->getExistingAttempts($identifier);
 		$currentTime = $this->timeFactory->getTime();
 
-		// Unset all attempts older than $period
-		foreach ($existingAttempts as $key => $attempt) {
-			if (($attempt + $period) < $currentTime) {
+		// Unset all attempts that are already expired
+		foreach ($existingAttempts as $key => $expirationTime) {
+			if ($expirationTime < $currentTime) {
 				unset($existingAttempts[$key]);
 			}
 		}
 		$existingAttempts = array_values($existingAttempts);
 
 		// Store the new attempt
-		$existingAttempts[] = (string)$currentTime;
+		$existingAttempts[] = (string)($currentTime + $period);
 		$this->cache->set($identifier, json_encode($existingAttempts));
 	}
 }
diff --git a/lib/private/Security/RateLimiting/Limiter.php b/lib/private/Security/RateLimiting/Limiter.php
index ede72e887fc..91657452d99 100644
--- a/lib/private/Security/RateLimiting/Limiter.php
+++ b/lib/private/Security/RateLimiting/Limiter.php
@@ -29,23 +29,17 @@ namespace OC\Security\RateLimiting;
 use OC\Security\Normalizer\IpAddress;
 use OC\Security\RateLimiting\Backend\IBackend;
 use OC\Security\RateLimiting\Exception\RateLimitExceededException;
-use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\IUser;
 
 class Limiter {
 	/** @var IBackend */
 	private $backend;
-	/** @var ITimeFactory */
-	private $timeFactory;
 
 	/**
-	 * @param ITimeFactory $timeFactory
 	 * @param IBackend $backend
 	 */
-	public function __construct(ITimeFactory $timeFactory,
-								IBackend $backend) {
+	public function __construct(IBackend $backend) {
 		$this->backend = $backend;
-		$this->timeFactory = $timeFactory;
 	}
 
 	/**
@@ -59,12 +53,12 @@ class Limiter {
 							  string $userIdentifier,
 							  int $period,
 							  int $limit): void {
-		$existingAttempts = $this->backend->getAttempts($methodIdentifier, $userIdentifier, $period);
+		$existingAttempts = $this->backend->getAttempts($methodIdentifier, $userIdentifier);
 		if ($existingAttempts >= $limit) {
 			throw new RateLimitExceededException();
 		}
 
-		$this->backend->registerAttempt($methodIdentifier, $userIdentifier, $this->timeFactory->getTime());
+		$this->backend->registerAttempt($methodIdentifier, $userIdentifier, $period);
 	}
 
 	/**
diff --git a/lib/private/Server.php b/lib/private/Server.php
index 6b6a1402a04..a9ea07c27d3 100644
--- a/lib/private/Server.php
+++ b/lib/private/Server.php
@@ -787,10 +787,20 @@ class Server extends ServerContainer implements IServerContainer {
 		$this->registerDeprecatedAlias('Search', ISearch::class);
 
 		$this->registerService(\OC\Security\RateLimiting\Backend\IBackend::class, function ($c) {
-			return new \OC\Security\RateLimiting\Backend\MemoryCache(
-				$this->get(ICacheFactory::class),
-				new \OC\AppFramework\Utility\TimeFactory()
-			);
+			$cacheFactory = $c->get(ICacheFactory::class);
+			if ($cacheFactory->isAvailable()) {
+				$backend = new \OC\Security\RateLimiting\Backend\MemoryCacheBackend(
+					$this->get(ICacheFactory::class),
+					new \OC\AppFramework\Utility\TimeFactory()
+				);
+			} else {
+				$backend = new \OC\Security\RateLimiting\Backend\DatabaseBackend(
+					$c->get(IDBConnection::class),
+					new \OC\AppFramework\Utility\TimeFactory()
+				);
+			}
+
+			return $backend;
 		});
 
 		$this->registerAlias(\OCP\Security\ISecureRandom::class, SecureRandom::class);