security #cve-2022-24894 [HttpKernel] Remove private headers before storing responses with HttpCache (nicolas-grekas)

This PR was merged into the 4.4 branch.

Author: nicolas-grekas

HttpCache/Store.php

@@ -26,19 +26,29 @@ class Store implements StoreInterface
 {
     protected $root;
     private $keyCache;
-    private $locks;
+    private $locks = [];
+    private $options;
 
     /**
+     * Constructor.
+     *
+     * The available options are:
+     *
+     *   * private_headers  Set of response headers that should not be stored
+     *                      when a response is cached. (default: Set-Cookie)
+     *
      * @throws \RuntimeException
      */
-    public function __construct(string $root)
+    public function __construct(string $root, array $options = [])
     {
         $this->root = $root;
         if (!file_exists($this->root) && !@mkdir($this->root, 0777, true) && !is_dir($this->root)) {
             throw new \RuntimeException(sprintf('Unable to create the store directory (%s).', $this->root));
         }
         $this->keyCache = new \SplObjectStorage();
-        $this->locks = [];
+        $this->options = array_merge([
+            'private_headers' => ['Set-Cookie'],
+        ], $options);
     }
 
     /**
@@ -215,6 +225,10 @@ public function write(Request $request, Response $response)
         $headers = $this->persistResponse($response);
         unset($headers['age']);
 
+        foreach ($this->options['private_headers'] as $h) {
+            unset($headers[strtolower($h)]);
+        }
+
         array_unshift($entries, [$storedEnv, $headers]);
 
         if (!$this->save($key, serialize($entries))) {

Tests/HttpCache/StoreTest.php

@@ -12,8 +12,10 @@
 namespace Symfony\Component\HttpKernel\Tests\HttpCache;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpFoundation\Cookie;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\HttpCache\HttpCache;
 use Symfony\Component\HttpKernel\HttpCache\Store;
 
 class StoreTest extends TestCase
@@ -317,6 +319,17 @@ public function testPurgeHttpAndHttps()
         $this->assertEmpty($this->getStoreMetadata($requestHttps));
     }
 
+    public function testDoesNotStorePrivateHeaders()
+    {
+        $request = Request::create('https://example.com/foo');
+        $response = new Response('foo');
+        $response->headers->setCookie(Cookie::fromString('foo=bar'));
+
+        $this->store->write($request, $response);
+        $this->assertArrayNotHasKey('set-cookie', $this->getStoreMetadata($request)[0][1]);
+        $this->assertNotEmpty($response->headers->getCookies());
+    }
+
     protected function storeSimpleEntry($path = null, $headers = [])
     {
         if (null === $path) {