Use Illuminate Session component instead of Symfony

Symfony's component relies on PHP's native session functionality, which
is not ideal. It automatically sets its own cookie headers, resulting in
this issue: https://github.com/flarum/core/issues/1084#issuecomment-364569953

The Illuminate component is more powerful and has a simpler API for
extension with other drivers and such, and fits in nicely with other
components we use (the majority of which are from Illuminate).

framework/core/composer.json

@@ -35,6 +35,7 @@
         "illuminate/filesystem": "5.5.*",
         "illuminate/hashing": "5.5.*",
         "illuminate/mail": "5.5.*",
+        "illuminate/session": "5.5.*",
         "illuminate/support": "5.5.*",
         "illuminate/validation": "5.5.*",
         "illuminate/view": "5.5.*",

framework/core/src/Forum/Controller/AbstractOAuth2Controller.php

@@ -62,7 +62,7 @@ abstract class AbstractOAuth2Controller implements ControllerInterface
 
         if (! $code) {
             $authUrl = $this->provider->getAuthorizationUrl($this->getAuthorizationUrlOptions());
-            $session->set('oauth2state', $this->provider->getState());
+            $session->put('oauth2state', $this->provider->getState());
 
             return new RedirectResponse($authUrl.'&display=popup');
         } elseif (! $state || $state !== $session->get('oauth2state')) {

framework/core/src/Forum/Controller/LogOutController.php

@@ -102,7 +102,7 @@ class LogOutController implements ControllerInterface
 
         // If a valid CSRF token hasn't been provided, show a view which will
         // allow the user to press a button to complete the log out process.
-        $csrfToken = $session->get('csrf_token');
+        $csrfToken = $session->token();
 
         if (array_get($request->getQueryParams(), 'token') !== $csrfToken) {
             $return = array_get($request->getQueryParams(), 'return');

framework/core/src/Forum/Controller/ResetPasswordController.php

@@ -50,6 +50,6 @@ class ResetPasswordController extends AbstractHtmlController
 
         return $this->view->make('flarum.forum::reset-password')
             ->with('passwordToken', $token->id)
-            ->with('csrfToken', $request->getAttribute('session')->get('csrf_token'));
+            ->with('csrfToken', $request->getAttribute('session')->token());
     }
 }

framework/core/src/Foundation/Application.php

@@ -718,6 +718,8 @@ class Application extends Container implements ApplicationContract
             'filesystem.cloud'     => [\Illuminate\Contracts\Filesystem\Cloud::class],
             'hash'                 => [\Illuminate\Contracts\Hashing\Hasher::class],
             'mailer'               => [\Illuminate\Mail\Mailer::class, \Illuminate\Contracts\Mail\Mailer::class, \Illuminate\Contracts\Mail\MailQueue::class],
+            'session'              => [\Illuminate\Session\SessionManager::class],
+            'session.driver'       => [\Illuminate\Contracts\Session\Session::class],
             'validator'            => [\Illuminate\Validation\Factory::class, \Illuminate\Contracts\Validation\Factory::class],
             'view'                 => [\Illuminate\View\Factory::class, \Illuminate\Contracts\View\Factory::class],
         ];

framework/core/src/Foundation/Site.php

@@ -33,6 +33,7 @@ use Illuminate\Config\Repository as ConfigRepository;
 use Illuminate\Filesystem\FilesystemServiceProvider;
 use Illuminate\Hashing\HashServiceProvider;
 use Illuminate\Mail\MailServiceProvider;
+use Illuminate\Session\SessionServiceProvider;
 use Illuminate\Validation\ValidationServiceProvider;
 use Illuminate\View\ViewServiceProvider;
 use Monolog\Formatter\LineFormatter;
@@ -169,6 +170,7 @@ class Site
         $app->register(FilesystemServiceProvider::class);
         $app->register(HashServiceProvider::class);
         $app->register(MailServiceProvider::class);
+        $app->register(SessionServiceProvider::class);
         $app->register(ViewServiceProvider::class);
         $app->register(ValidationServiceProvider::class);
 
@@ -236,6 +238,15 @@ class Site
                         'root'   => $app->publicPath().'/assets/avatars'
                     ]
                 ]
+            ],
+            'session' => [
+                'driver' => 'file',
+                'lifetime' => 120,
+                'expire_on_close' => false,
+                'encrypt' => false,
+                'files' => $app->storagePath().'/sessions',
+                'lottery' => [2, 100],
+                'cookie' => 'session'
             ]
         ]);
     }

framework/core/src/Frontend/FrontendView.php

@@ -464,7 +464,7 @@ class FrontendView
 
         return [
             'userId' => $actor->id,
-            'csrfToken' => $session->get('csrf_token')
+            'csrfToken' => $session->token()
         ];
     }
 

framework/core/src/Http/Middleware/AuthenticateWithSession.php

@@ -13,10 +13,10 @@ namespace Flarum\Http\Middleware;
 
 use Flarum\User\Guest;
 use Flarum\User\User;
+use Illuminate\Contracts\Session\Session;
 use Interop\Http\ServerMiddleware\DelegateInterface;
 use Interop\Http\ServerMiddleware\MiddlewareInterface;
 use Psr\Http\Message\ServerRequestInterface as Request;
-use Symfony\Component\HttpFoundation\Session\SessionInterface;
 
 class AuthenticateWithSession implements MiddlewareInterface
 {
@@ -33,7 +33,7 @@ class AuthenticateWithSession implements MiddlewareInterface
         return $delegate->process($request);
     }
 
-    private function getActor(SessionInterface $session)
+    private function getActor(Session $session)
     {
         $actor = User::find($session->get('user_id')) ?: new Guest;
 

framework/core/src/Http/Middleware/RememberFromCookie.php

@@ -12,15 +12,29 @@
 namespace Flarum\Http\Middleware;
 
 use Flarum\Http\AccessToken;
+use Flarum\Http\CookieFactory;
 use Interop\Http\ServerMiddleware\DelegateInterface;
 use Interop\Http\ServerMiddleware\MiddlewareInterface;
 use Psr\Http\Message\ServerRequestInterface as Request;
 
 class RememberFromCookie implements MiddlewareInterface
 {
+    /**
+     * @var CookieFactory
+     */
+    protected $cookie;
+
+    /**
+     * @param CookieFactory $cookie
+     */
+    public function __construct(CookieFactory $cookie)
+    {
+        $this->cookie = $cookie;
+    }
+
     public function process(Request $request, DelegateInterface $delegate)
     {
-        $id = array_get($request->getCookieParams(), 'flarum_remember');
+        $id = array_get($request->getCookieParams(), $this->cookie->getName('remember'));
 
         if ($id) {
             $token = AccessToken::find($id);
@@ -28,8 +42,9 @@ class RememberFromCookie implements MiddlewareInterface
             if ($token) {
                 $token->touch();
 
+                /** @var \Illuminate\Contracts\Session\Session $session */
                 $session = $request->getAttribute('session');
-                $session->set('user_id', $token->user_id);
+                $session->put('user_id', $token->user_id);
             }
         }
 

framework/core/src/Http/Middleware/StartSession.php

@@ -13,17 +13,19 @@ namespace Flarum\Http\Middleware;
 
 use Dflydev\FigCookies\FigResponseCookies;
 use Flarum\Http\CookieFactory;
-use Illuminate\Support\Str;
+use Illuminate\Contracts\Session\Session;
+use Illuminate\Session\SessionManager;
 use Interop\Http\ServerMiddleware\DelegateInterface;
 use Interop\Http\ServerMiddleware\MiddlewareInterface;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
-use Symfony\Component\HttpFoundation\Session\Session;
-use Symfony\Component\HttpFoundation\Session\SessionInterface;
 
 class StartSession implements MiddlewareInterface
 {
-    const COOKIE_NAME = 'session';
+    /**
+     * @var SessionManager
+     */
+    protected $manager;
 
     /**
      * @var CookieFactory
@@ -31,54 +33,75 @@ class StartSession implements MiddlewareInterface
     protected $cookie;
 
     /**
+     * @param SessionManager $manager
      * @param CookieFactory $cookie
      */
-    public function __construct(CookieFactory $cookie)
+    public function __construct(SessionManager $manager, CookieFactory $cookie)
     {
+        $this->manager = $manager;
         $this->cookie = $cookie;
     }
 
     public function process(Request $request, DelegateInterface $delegate)
     {
-        $session = $this->startSession();
+        $request = $request->withAttribute('session',
+            $session = $this->startSession($request)
+        );
 
-        $request = $request->withAttribute('session', $session);
+        $this->collectGarbage($session);
 
         $response = $delegate->process($request);
 
+        $session->save();
+
         $response = $this->withCsrfTokenHeader($response, $session);
 
         return $this->withSessionCookie($response, $session);
     }
 
-    private function startSession()
+    private function startSession(Request $request)
     {
-        $session = new Session;
+        $session = $this->manager->driver();
 
-        $session->setName($this->cookie->getName(self::COOKIE_NAME));
+        $id = array_get($request->getCookieParams(), $this->cookie->getName($session->getName()));
+
+        $session->setId($id);
         $session->start();
 
-        if (! $session->has('csrf_token')) {
-            $session->set('csrf_token', Str::random(40));
-        }
-
         return $session;
     }
 
-    private function withCsrfTokenHeader(Response $response, SessionInterface $session)
+    private function collectGarbage(Session $session)
     {
-        if ($session->has('csrf_token')) {
-            $response = $response->withHeader('X-CSRF-Token', $session->get('csrf_token'));
+        $config = $this->manager->getSessionConfig();
+
+        if ($this->configHitsLottery($config)) {
+            $session->getHandler()->gc($this->getSessionLifetimeInSeconds());
         }
+    }
+
+    private function configHitsLottery(array $config)
+    {
+        return random_int(1, $config['lottery'][1]) <= $config['lottery'][0];
+    }
+
+    private function withCsrfTokenHeader(Response $response, Session $session)
+    {
+        $response = $response->withHeader('X-CSRF-Token', $session->token());
 
         return $response;
     }
 
-    private function withSessionCookie(Response $response, SessionInterface $session)
+    private function withSessionCookie(Response $response, Session $session)
     {
         return FigResponseCookies::set(
             $response,
-            $this->cookie->make(self::COOKIE_NAME, $session->getId())
+            $this->cookie->make($session->getName(), $session->getId(), $this->getSessionLifetimeInSeconds())
         );
     }
+
+    private function getSessionLifetimeInSeconds()
+    {
+        return ($this->manager->getSessionConfig()['lifetime'] ?? null) * 60;
+    }
 }

framework/core/src/Http/SessionAuthenticator.php

@@ -11,25 +11,26 @@
 
 namespace Flarum\Http;
 
-use Symfony\Component\HttpFoundation\Session\SessionInterface;
+use Illuminate\Contracts\Session\Session;
 
 class SessionAuthenticator
 {
     /**
-     * @param SessionInterface $session
+     * @param Session $session
      * @param int $userId
      */
-    public function logIn(SessionInterface $session, $userId)
+    public function logIn(Session $session, $userId)
     {
-        $session->migrate();
-        $session->set('user_id', $userId);
+        $session->regenerate(true);
+        $session->put('user_id', $userId);
     }
 
     /**
-     * @param SessionInterface $session
+     * @param Session $session
      */
-    public function logOut(SessionInterface $session)
+    public function logOut(Session $session)
     {
         $session->invalidate();
+        $session->regenerateToken();
     }
 }

framework/core/src/User/User.php

@@ -34,7 +34,7 @@ use Flarum\User\Event\PasswordChanged;
 use Flarum\User\Event\Registered;
 use Flarum\User\Event\Renamed;
 use Illuminate\Contracts\Hashing\Hasher;
-use Symfony\Component\HttpFoundation\Session\SessionInterface;
+use Illuminate\Contracts\Session\Session;
 
 /**
  * @property int $id
@@ -698,7 +698,7 @@ class User extends AbstractModel
     }
 
     /**
-     * @return SessionInterface
+     * @return Session
      */
     public function getSession()
     {
@@ -706,9 +706,9 @@ class User extends AbstractModel
     }
 
     /**
-     * @param SessionInterface $session
+     * @param Session $session
      */
-    public function setSession(SessionInterface $session)
+    public function setSession(Session $session)
     {
         $this->session = $session;
     }