Fixing session key, removing valid_keys which was painful to transport

the whitelist in the session (see #36)

Controller/CaptchaController.php

@@ -24,7 +24,18 @@ class CaptchaController extends Controller
     public function generateCaptchaAction(Request $request, $key)
     {
         $options = $this->container->getParameter('gregwar_captcha.config');
-        if (!$options['as_url'] || !in_array($key, $options['valid_keys'])) {
+        $session = $this->get('session');
+        $whitelistKey = $options['whitelist_key'];
+        $isOk = false;
+
+        if ($options['as_url'] && $session->has($whitelistKey)) {
+            $keys = $session->get($whitelistKey);
+            if (is_array($keys) && in_array($key, $keys)) {
+                $isOk = true;
+            }
+        }
+
+        if (!$isOk) {
             return $this->createNotFoundException('Unable to generate a captcha via a URL without the proper configuration.');
         }
 

DependencyInjection/Configuration.php

@@ -35,7 +35,7 @@ class Configuration implements ConfigurationInterface
                 ->scalarNode('quality')->defaultValue(15)->end()
                 ->scalarNode('invalid_message')->defaultValue('Bad code value')->end()
                 ->scalarNode('bypass_code')->defaultValue(null)->end()
-                ->arrayNode('valid_keys')->defaultValue(array('captcha'))->prototype('scalar')->end()
+                ->scalarNode('whitelist_key')->defaultValue('captcha_whitelist_key')->end()
             ->end()
         ;
 

DependencyInjection/GregwarCaptchaExtension.php

@@ -31,6 +31,7 @@ class GregwarCaptchaExtension extends Extension
         $container->setParameter('gregwar_captcha.config.web_path', $config['web_path']);
         $container->setParameter('gregwar_captcha.config.gc_freq', $config['gc_freq']);
         $container->setParameter('gregwar_captcha.config.expiration', $config['expiration']);
+        $container->setParameter('gregwar_captcha.config.whitelist_key', $config['whitelist_key']);
 
         $resources = $container->getParameter('twig.form.resources');
         $container->setParameter('twig.form.resources', array_merge(array('GregwarCaptchaBundle::captcha.html.twig'), $resources));

Generator/CaptchaGenerator.php

@@ -16,6 +16,12 @@ class CaptchaGenerator
      */
     protected $session;
 
+    /**
+     * Name of the whitelist key
+     * @var string
+     */
+    protected $whitelistKey;
+
     /**
      * @var \Symfony\Component\Routing\RouterInterface
      */
@@ -65,7 +71,7 @@ class CaptchaGenerator
      * @param int $gcFreq
      * @param int $expiration
      */
-    public function __construct(SessionInterface $session, RouterInterface $router, $imageFolder, $webPath, $gcFreq, $expiration)
+    public function __construct(SessionInterface $session, RouterInterface $router, $imageFolder, $webPath, $gcFreq, $expiration, $whitelistKey)
     {
         $this->session          = $session;
         $this->router           = $router;
@@ -73,6 +79,7 @@ class CaptchaGenerator
         $this->webPath          = $webPath;
         $this->gcFreq           = $gcFreq;
         $this->expiration       = $expiration;
+        $this->whitelistKey     = $whitelistKey;
     }
 
     /**
@@ -96,6 +103,11 @@ class CaptchaGenerator
 
         // Returns the configured URL for image generation
         if ($options['as_url']) {
+            $keys = $this->session->get($this->whitelistKey, array());
+            if (!in_array($key, $keys)) {
+                $keys[] = $key;
+            }
+            $this->session->set($this->whitelistKey, $keys);
             return $this->router->generate('gregwar_captcha.generate_captcha', array('key' => $key));
         }
 

README.md

@@ -132,7 +132,7 @@ You can define the following configuration options globally or on the CaptchaTyp
 * **as_url**: if set to true, a URL will be used in the image tag and will handle captcha generation. This can be used in a multiple-server environment and support IE6/7 (default=false)
 * **invalid_message**: error message displayed when an non-matching code is submitted (default="Bad code value")
 * **bypass_code**: code that will always validate the captcha (default=null)
-* **valid_keys**: names that are able to be used for a captcha form type (default=[captcha])
+* **whitelist_key**: the session key to use for keep the session keys that can be used for captcha storage, when using as_url (default=captcha_whitelist_key)
 
 Example :
 
@@ -167,10 +167,7 @@ This will use the bundle's route of "/generate-captcha/{key}" to handle the gene
         resource: "@GregwarCaptchaBundle/Resources/config/routing/routing.yml"
         prefix: /_gcb
 
-If you are using multiple captchas or assigning names other than the default "captcha", you will need to whitelist your captcha names in the "valid_keys" configuration:
-
-    gregwar_captcha:
-        valid_keys: [registration_captcha, confirmation_captcha]
+Since the session key is transported in the URL, it's also added in another session array, under the `whitelist_key` key, for security reasons
 
 Form Theming
 ============

Resources/config/services.yml

@@ -19,3 +19,4 @@ services:
             - %gregwar_captcha.config.web_path%
             - %gregwar_captcha.config.gc_freq%
             - %gregwar_captcha.config.expiration%
+            - %gregwar_captcha.config.whitelist_key%

Type/CaptchaType.php

@@ -25,6 +25,12 @@ class CaptchaType extends AbstractType
      */
     protected $session;
 
+    /**
+     * The session key
+     * @var string
+     */
+    protected $key = null;
+
     /**
      * @var \Gregwar\CaptchaBundle\Generator\CaptchaGenerator
      */
@@ -54,9 +60,11 @@ class CaptchaType extends AbstractType
      */
     public function buildForm(FormBuilderInterface $builder, array $options)
     {
+        $this->key = 'gcb_'.$builder->getForm()->getName();
+
         $validator = new CaptchaValidator(
             $this->session,
-            $builder->getForm()->getName(),
+            $this->key,
             $options['invalid_message'],
             $options['bypass_code']
         );
@@ -74,7 +82,7 @@ class CaptchaType extends AbstractType
         $view->vars = array_merge($view->vars, array(
             'captcha_width'     => $options['width'],
             'captcha_height'    => $options['height'],
-            'captcha_code'      => $this->generator->getCaptchaCode($form->getName(), $options),
+            'captcha_code'      => $this->generator->getCaptchaCode($this->key, $options),
             'value'             => '',
         ));
     }