bug symfony#24101 [Security] Fix exception when use_referer option is true and referer is not set or empty (linniksa)

This PR was submitted for the master branch but it was merged into the 2.7 branch instead (closes symfony#24101).

Discussion
----------

[Security] Fix exception when use_referer option is true and referer is not set or empty

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| License       | MIT

Commits
-------

a29e069 [Security] Fix exception when use_referer option is true and referer is not set or empty

Author: fabpot

src/Symfony/Component/Security/Http/Authentication/DefaultAuthenticationSuccessHandler.php

@@ -118,12 +118,11 @@ protected function determineTargetUrl(Request $request)
             return $targetUrl;
         }
 
-        if ($this->options['use_referer']) {
-            $targetUrl = $request->headers->get('Referer');
+        if ($this->options['use_referer'] && $targetUrl = $request->headers->get('Referer')) {
             if (false !== $pos = strpos($targetUrl, '?')) {
                 $targetUrl = substr($targetUrl, 0, $pos);
             }
-            if ($targetUrl !== $this->httpUtils->generateUri($request, $this->options['login_path'])) {
+            if ($targetUrl && $targetUrl !== $this->httpUtils->generateUri($request, $this->options['login_path'])) {
                 return $targetUrl;
             }
         }

src/Symfony/Component/Security/Http/Tests/Authentication/DefaultAuthenticationSuccessHandlerTest.php

@@ -83,6 +83,16 @@ public function getRequestRedirections()
                 array(),
                 '/',
             ),
+            'target path as referer when referer not set' => array(
+                Request::create('/'),
+                array('use_referer' => true),
+                '/',
+            ),
+            'target path as referer when referer is ?' => array(
+                Request::create('/', 'GET', array(), array(), array(), array('HTTP_REFERER' => '?')),
+                array('use_referer' => true),
+                '/',
+            ),
             'target path should be different than login URL' => array(
                 Request::create('/', 'GET', array(), array(), array(), array('HTTP_REFERER' => 'http://localhost/login')),
                 array('use_referer' => true, 'login_path' => '/login'),