HTTP CSRF Protection - Middleware (PSR15)

PSR15 Middleware to protect your application againts Cross-Site Request Forgery

This middleware use the Cookies to store a token used for comparaison in each "unsafe" request (POST/PUT/PATCH/DELETE).

Why?

Because.

Installation

$ composer require chiron/csrf

To activate the extension:

[
    //...
    XXX\CsrfBootloader::class,
]

The extension will activate Chiron\Csrf\Middleware\CsrfTokenMiddleware to issue a unique token for every user request.

Enable Protection - Specific Route

The extension provides a middleware CsrfProtectionMiddleware which activates the protection on your routes (specific route or every routes). This middleware will protect all the requests for the "unsafe" methods POST, PUT, PATCH, DELETE.

use Chiron\Csrf\Middleware\CsrfProtectionMiddleware;

// ...

public function boot(RouterInterface $router)
{
    $route = new Route('/', new Target\Action(HomeController::class, 'index'));

    $router->setRoute(
        'index',
        $route->withMiddleware(CsrfProtectionMiddleware::class)
    );
}

Enable Protection - All Routes

To activate CSRF protection on all the routes, you need to "globally" register Chiron\Csrf\Middleware\CsrfProtectionMiddleware via MiddlewareQueue:

use Chiron\Csrf\Middleware\CsrfProtectionMiddleware;

// ...

public function boot(MiddlewareQueue $middlewares)
{
    $middlewares->addMiddleware(CsrfProtectionMiddleware::class);
}

Usage

Once the protection is activated, you must sign every request with the token available via PSR-7 attribute csrfToken.

To receive this token in the controller or view:

public function index(ServerRequestInterface $request)
{
    $csrfToken = $request->getAttribute('csrfToken');
}

Every POST/PUT/PATCH/DELETE request from the user must include this token as POST parameter csrf-token or header X-CSRF-Token.

Users will receive an error 403 Forbidden if a token is missing.

Users will receive an error 412 Precondition Failed if the token has been tampered (and the cookie will be deleted).

public function index(ServerRequestInterface $request)
{
    $form = '
        <form method="post">
          <input type="hidden" name="csrf-token" value="{csrfToken}"/>
          <input type="text" name="value"/>
          <input type="submit"/>
        </form>
    ';

    $form = str_replace(
        '{csrfToken}',
        $request->getAttribute('csrfToken'),
        $form
    );

    return $form;
}

TODO

Add documentation on the "csrf_token()" helper.
Create a TwigExtension class to add the csrf_token.