bug symfony#50552 [Security] Allow custom scheme to be used as redirection URIs (Spomky)

This PR was merged into the 5.4 branch.

Discussion
----------

[Security] Allow custom scheme to be used as redirection URIs

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | yes
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tickets       | Fix symfony#50500
| License       | MIT
| Doc PR        | not needed

ping `@sdespont` and `@MatTheCat`

This PR aims at fixing the redirection issue where only URLs starting with `http` are allowed.
With the modified behavior, it is now allowed to use any URL scheme. It will be possible to redirect to `android-app://com.google.android.gm/`.

~In addition, it prevents the redirection to the following URLs:~

* ~With path traversal e.g. `https://example.com/foo/../../.htpasswd`~
* ~With protocol-relative e.g. `//malicious.app/foo/bar`~

Commits
-------

3a6969f [Security] Allow custom scheme to be used as redirection URIs

Author: nicolas-grekas

src/Symfony/Component/Security/Http/HttpUtils.php

@@ -148,7 +148,9 @@ public function checkRequestPath(Request $request, string $path)
      */
     public function generateUri(Request $request, string $path)
     {
-        if (str_starts_with($path, 'http') || !$path) {
+        $url = parse_url($path);
+
+        if ('' === $path || isset($url['scheme'], $url['host'])) {
             return $path;
         }
 

src/Symfony/Component/Security/Http/Tests/HttpUtilsTest.php

@@ -58,6 +58,54 @@ public function testCreateRedirectResponseWithRequestsDomain()
         $this->assertTrue($response->isRedirect('http://localhost/blog'));
     }
 
+    /**
+     * @dataProvider validRequestDomainUrls
+     */
+    public function testCreateRedirectResponse(?string $domainRegexp, string $path, string $expectedRedirectUri)
+    {
+        $utils = new HttpUtils($this->getUrlGenerator(), null, $domainRegexp);
+        $response = $utils->createRedirectResponse($this->getRequest(), $path);
+
+        $this->assertTrue($response->isRedirect($expectedRedirectUri));
+        $this->assertEquals(302, $response->getStatusCode());
+    }
+
+    public static function validRequestDomainUrls()
+    {
+        return [
+            '/foobar' => [
+                null,
+                '/foobar',
+                'http://localhost/foobar',
+            ],
+            'http://symfony.com/ without domain regex' => [
+                null,
+                'http://symfony.com/',
+                'http://symfony.com/',
+            ],
+            'http://localhost/blog with #^https?://symfony\.com$#i' => [
+                '#^https?://symfony\.com$#i',
+                'http://symfony.com/blog',
+                'http://symfony.com/blog',
+            ],
+            'http://localhost/blog with #^https?://%s$#i' => [
+                '#^https?://%s$#i',
+                'http://localhost/blog',
+                'http://localhost/blog',
+            ],
+            'custom scheme' => [
+                null,
+                'android-app://com.google.android.gm/',
+                'android-app://com.google.android.gm/',
+            ],
+            'custom scheme with all URL components' => [
+                null,
+                'android-app://foo:[email protected]:8080/software/index.html?lite=true#section1',
+                'android-app://foo:[email protected]:8080/software/index.html?lite=true#section1',
+            ],
+        ];
+    }
+
     /**
      * @dataProvider badRequestDomainUrls
      */
@@ -77,6 +125,7 @@ public static function badRequestDomainUrls()
             ['http:/\\pirate.net/foo'],
             ['http:\\/pirate.net/foo'],
             ['http://////pirate.net/foo'],
+            ['http:///foo'],
         ];
     }