feature symfony#38395 [lock] Prevent user serializing the key when store does not support it. (jderusse)

This PR was merged into the 5.2-dev branch.

Discussion
----------

[lock] Prevent user serializing the key when store does not support it.

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Tickets       | /
| License       | MIT
| Doc PR        | /

Some store relies on connection with the running process. ie. kernel relaease flock/semaphore, or zookeeper neeeds a connection to the database.

When the users tries to serialize the key to send it to another process, they are not aware that they lose the lock.

This PR throws an exception in that situation.

Commits
-------

1ec0630 Prevent user serializing the key

Author: fabpot

src/Symfony/Component/Lock/Exception/UnserializableKeyException.php

@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Lock\Exception;
+
+/**
+ * UnserializableKeyException is thrown when the key contains state that can no
+ * be serialized and the user try to serialize it.
+ * ie. Connection with a database, flock, semaphore, ...
+ *
+ * @author Jérémy Derussé <[email protected]>
+ */
+class UnserializableKeyException extends \RuntimeException implements ExceptionInterface
+{
+}

src/Symfony/Component/Lock/Key.php

@@ -11,6 +11,8 @@
 
 namespace Symfony\Component\Lock;
 
+use Symfony\Component\Lock\Exception\UnserializableKeyException;
+
 /**
  * Key is a container for the state of the locks in stores.
  *
@@ -21,6 +23,7 @@ final class Key
     private $resource;
     private $expiringTime;
     private $state = [];
+    private $serializable = true;
 
     public function __construct(string $resource)
     {
@@ -52,6 +55,11 @@ public function getState(string $stateKey)
         return $this->state[$stateKey];
     }
 
+    public function markUnserializable(): void
+    {
+        $this->serializable = false;
+    }
+
     public function resetLifetime()
     {
         $this->expiringTime = null;
@@ -83,4 +91,13 @@ public function isExpired(): bool
     {
         return null !== $this->expiringTime && $this->expiringTime <= microtime(true);
     }
+
+    public function __sleep(): array
+    {
+        if (!$this->serializable) {
+            throw new UnserializableKeyException('The key can not be serialized.');
+        }
+
+        return ['resource', 'expiringTime', 'state'];
+    }
 }

src/Symfony/Component/Lock/Store/FlockStore.php

@@ -125,6 +125,7 @@ private function lock(Key $key, bool $read, bool $blocking)
         }
 
         $key->setState(__CLASS__, [$read, $handle]);
+        $key->markUnserializable();
     }
 
     /**

src/Symfony/Component/Lock/Store/SemaphoreStore.php

@@ -76,6 +76,7 @@ private function lock(Key $key, bool $blocking)
         }
 
         $key->setState(__CLASS__, $resource);
+        $key->markUnserializable();
     }
 
     /**

src/Symfony/Component/Lock/Store/ZookeeperStore.php

@@ -65,6 +65,7 @@ public function save(Key $key)
         $token = $this->getUniqueToken($key);
 
         $this->createNewLock($resource, $token);
+        $key->markUnserializable();
 
         $this->checkNotExpired($key);
     }

src/Symfony/Component/Lock/Tests/KeyTest.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Lock\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Lock\Exception\UnserializableKeyException;
+use Symfony\Component\Lock\Key;
+
+/**
+ * @author Jérémy Derussé <[email protected]>
+ */
+class KeyTest extends TestCase
+{
+    public function testSerialize()
+    {
+        $key = new Key(__METHOD__);
+        $key->reduceLifetime(1);
+        $key->setState('foo', 'bar');
+
+        $copy = unserialize(serialize($key));
+        $this->assertSame($key->getState('foo'), $copy->getState('foo'));
+        $this->assertEqualsWithDelta($key->getRemainingLifetime(), $copy->getRemainingLifetime(), 0.001);
+    }
+
+    public function testUnserialize()
+    {
+        $key = new Key(__METHOD__);
+        $key->markUnserializable();
+
+        $this->expectException(UnserializableKeyException::class);
+        serialize($key);
+    }
+}

src/Symfony/Component/Lock/Tests/Store/FlockStoreTest.php

@@ -22,6 +22,7 @@ class FlockStoreTest extends AbstractStoreTest
 {
     use BlockingStoreTestTrait;
     use SharedLockStoreTestTrait;
+    use UnserializableTestTrait;
 
     /**
      * {@inheritdoc}

src/Symfony/Component/Lock/Tests/Store/SemaphoreStoreTest.php

@@ -23,6 +23,7 @@
 class SemaphoreStoreTest extends AbstractStoreTest
 {
     use BlockingStoreTestTrait;
+    use UnserializableTestTrait;
 
     /**
      * {@inheritdoc}

src/Symfony/Component/Lock/Tests/Store/UnserializableTestTrait.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Lock\Tests\Store;
+
+use Symfony\Component\Lock\Exception\UnserializableKeyException;
+use Symfony\Component\Lock\Key;
+use Symfony\Component\Lock\PersistingStoreInterface;
+
+/**
+ * @author Jérémy Derussé <[email protected]>
+ */
+trait UnserializableTestTrait
+{
+    /**
+     * @see AbstractStoreTest::getStore()
+     *
+     * @return PersistingStoreInterface
+     */
+    abstract protected function getStore();
+
+    public function testUnserializableKey()
+    {
+        $store = $this->getStore();
+
+        $key = new Key(uniqid(__METHOD__, true));
+
+        $store->save($key);
+        $this->assertTrue($store->exists($key));
+
+        $this->expectException(UnserializableKeyException::class);
+        serialize($key);
+    }
+}

src/Symfony/Component/Lock/Tests/Store/ZookeeperStoreTest.php

@@ -23,6 +23,8 @@
  */
 class ZookeeperStoreTest extends AbstractStoreTest
 {
+    use UnserializableTestTrait;
+
     /**
      * @return ZookeeperStore
      */