feature symfony#24388 [Security] Look at headers for switch_user username (chalasr)

This PR was merged into the 3.4 branch.

Discussion
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[Security] Look at headers for switch_user username

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | symfony#24260
| License       | MIT
| Doc PR        | n/a

Allowing `switch_user.parameter` config node to be a header name.
It's supported by SwitchUserStatelessBundle and I think it makes sense.
Forgotten in symfony#24260 so targets 3.4 but not a blocker.

Commits
-------

3c80195 [Security] Look at headers for switch user username parameter

Author: fabpot

src/Symfony/Bundle/SecurityBundle/Tests/Functional/SwitchUserTest.php

@@ -54,7 +54,7 @@ public function testSwitchedUserExit()
     public function testSwitchUserStateless()
     {
         $client = $this->createClient(array('test_case' => 'JsonLogin', 'root_config' => 'switchuser_stateless.yml'));
-        $client->request('POST', '/chk', array('_switch_user' => 'dunglas'), array(), array('CONTENT_TYPE' => 'application/json'), '{"user": {"login": "user_can_switch", "password": "test"}}');
+        $client->request('POST', '/chk', array(), array(), array('HTTP_X_SWITCH_USER' => 'dunglas', 'CONTENT_TYPE' => 'application/json'), '{"user": {"login": "user_can_switch", "password": "test"}}');
         $response = $client->getResponse();
 
         $this->assertInstanceOf(JsonResponse::class, $response);

src/Symfony/Bundle/SecurityBundle/Tests/Functional/app/JsonLogin/switchuser_stateless.yml

@@ -10,4 +10,5 @@ security:
     firewalls:
         main:
             switch_user:
+                parameter: X-Switch-User
                 stateless: true

src/Symfony/Component/Security/Http/Firewall/SwitchUserListener.php

@@ -79,16 +79,17 @@ public function __construct(TokenStorageInterface $tokenStorage, UserProviderInt
     public function handle(GetResponseEvent $event)
     {
         $request = $event->getRequest();
+        $username = $request->get($this->usernameParameter) ?: $request->headers->get($this->usernameParameter);
 
-        if (!$request->get($this->usernameParameter)) {
+        if (!$username) {
             return;
         }
 
-        if (self::EXIT_VALUE === $request->get($this->usernameParameter)) {
+        if (self::EXIT_VALUE === $username) {
             $this->tokenStorage->setToken($this->attemptExitUser($request));
         } else {
             try {
-                $this->tokenStorage->setToken($this->attemptSwitchUser($request));
+                $this->tokenStorage->setToken($this->attemptSwitchUser($request, $username));
             } catch (AuthenticationException $e) {
                 throw new \LogicException(sprintf('Switch User failed: "%s"', $e->getMessage()));
             }
@@ -106,20 +107,21 @@ public function handle(GetResponseEvent $event)
     /**
      * Attempts to switch to another user.
      *
-     * @param Request $request A Request instance
+     * @param Request $request  A Request instance
+     * @param string  $username
      *
      * @return TokenInterface|null The new TokenInterface if successfully switched, null otherwise
      *
      * @throws \LogicException
      * @throws AccessDeniedException
      */
-    private function attemptSwitchUser(Request $request)
+    private function attemptSwitchUser(Request $request, $username)
     {
         $token = $this->tokenStorage->getToken();
         $originalToken = $this->getOriginalToken($token);
 
         if (false !== $originalToken) {
-            if ($token->getUsername() === $request->get($this->usernameParameter)) {
+            if ($token->getUsername() === $username) {
                 return $token;
             }
 
@@ -133,8 +135,6 @@ private function attemptSwitchUser(Request $request)
             throw $exception;
         }
 
-        $username = $request->get($this->usernameParameter);
-
         if (null !== $this->logger) {
             $this->logger->info('Attempting to switch to user.', array('username' => $username));
         }