Use constant time comparison in UriSigner

Author: stof

UriSigner.php

@@ -79,7 +79,7 @@ public function check($uri)
  $hash = $params[$this->parameter];
  unset($params[$this->parameter]);
 
- return $this->computeHash($this->buildUrl($url, $params)) === $hash;
+ return hash_equals($this->computeHash($this->buildUrl($url, $params)), $hash);
  }
 
  private function computeHash($uri)

composer.json

@@ -21,6 +21,7 @@
  "symfony/http-foundation": "~3.4.12|~4.0.12|^4.1.1",
  "symfony/debug": "^3.3.3|~4.0",
  "symfony/polyfill-ctype": "~1.8",
+ "symfony/polyfill-php56": "~1.8",
  "psr/log": "~1.0"
  },
  "require-dev": {