lumen-saml2: A PHP repository from ibpavlov

Lumen 5+ - Saml2

A Lumen package for Saml2 integration as a SP (service provider) based on OneLogin toolkit, which is much lighter and easier to install than simplesamlphp SP. It doesn't need separate routes or session storage to work!

The aim of this library is to be as simple as possible. We won't mess with Lumen users, auth, session... We prefer to limit ourselves to a concrete task. Ask the user to authenticate at the IDP and process the response. Same case for SLO requests.

Forked from "aacotroneo/laravel-saml2" and updated to work with Lumen

Installation - Composer

You can install the package via composer:

composer require ibpavlov/lumen-saml2

Or manually add this to your composer.json:

"ibpavlov/lumen-saml2": "*"

Then copy config files from vendor/ibpavlov/lumen-saml2/config to config folder. Then customize new files to match your configurations.

Apply configuration files and register the service in bootstrap/app.php:

$app->configure('saml2_settings');
$app->configure('saml2_test');

$app->register(Ibpavlov\Saml2\Saml2ServiceProvider::class);

The test_idp_settings.php config is handled almost directly by OneLogin so you should refer to that for full details, but we'll cover here what's really necessary. There are some other config about routes you may want to check, they are pretty strightforward.

Configuration

Define the IDPs

Define names of all the IDPs you want to configure in saml2_settings.php. Optionally keep 'test' as the first IDP if you want to use the simplesamlphp demo, and add real IDPs after that. The name of the IDP will show up in the URL used by the Saml2 routes this library makes, as well as internally in the filename for each IDP's config.

    'idpNames' => ['test', 'myidp1', 'myidp2'],

Configure lumen-saml2 to know about each IDP

You will need to create a separate configuration file for each IDP under app/config/saml2/ folder. e.g. myidp1_idp_settings.php. You can use test_idp_settings.php as the starting point; just copy it and rename it.

Configuration options are note explained in this project as they come from the OneLogin project, please refer there for details.

The only real difference between this config and the one that OneLogin uses, is that the SP entityId, assertionConsumerService url and singleLogoutService URL are injected by the library. If you don't specify those URLs in the corresponding IDP config optional values, this library provides defaults values: the metadata, acs, and sls routes that this library creates for each IDP. If specify different values in the config, note that the acs and sls URLs should correspond to actual routes that you set up that are directed to the corresponding Saml2Controller function.

If you want to optionally define values in ENV vars instead of the *_idp_settings file, you'll see in there that there is a naming pattern you can follow for ENV values. For example, if in myipd1_idp_settings.php you set $this_idp_env_id = 'MYIDP1';, and in myidp2_idp_settings.php you set it to 'SECONDIDP', then you can set ENV vars starting with SAML2_MYDP1_ and SAML2_SECONDIDP_, e.g.

SAML2_MYIDP1_SP_x509="..."
SAML2_MYIDP1_SP_PRIVATEKEY="..."
// Other  SAML2_MYIDP1_* values

SAML2_SECONDIDP_SP_x509="..."
SAML2_SECONDIDP_SP_PRIVATEKEY="..."
// Other SAML2_SECONDIDP_* values

URLs To Pass to The IDP configuration

As mentioned above, you don't need to implement the SP entityId, assertionConsumerService url and singleLogoutService routes, because Saml2Controller already does by default. But you need to know these routes, to provide them to the configuration of your actual IDP, i.e. the 3rd party you are asking to authenticate users.

You can check the actual routes in the metadata, by navigating to 'http(s)://laravel_url/myidp1/metadata', which incidentally will be the default entityId for this SP.

If you configure the optional routesPrefix setting in saml2_settings.php, then all idp routes will be prefixed by that value, so you'll need to adjust the metadata url accordingly. For example, if you configure routesPrefix to be 'single_sign_on', then your IDP metadata for myidp1 will be found at http://laravel_url/single_sign_on/myidp1/metadata.

Example: simplesamlphp IDP configuration

If you use simplesamlphp as a test IDP, and your SP metadata url is http://laravel_url/myidp1/metadata, add the following to /metadata/sp-remote.php to inform the IDP of your lumen-saml2 SP identity:

$metadata['http://lumen_url/myidp1/metadata'] = array(
    'AssertionConsumerService' => 'http://Lumen_url/myidp1/acs',
    'SingleLogoutService' => 'http://Lumen_url/myidp1/sls',
    //the following two affect what the $Saml2user->getUserId() will return
    'NameIDFormat' => 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
    'simplesaml.nameidattribute' => 'uid' 
);

Usage

When you want your user to login, just redirect to the login route configured for the particular IDP, route('saml2_login', 'myIdp1'). You can also instantiate a Saml2Auth for the desired IDP using the Saml2Auth::loadOneLoginAuthFromIpdConfig('myIdp1') function to load the config and construct the OneLogin auth argment; just remember that it does not use any session storage, so if you ask it to login it will redirect to the IDP whether the user is already logged in or not. For example, you can change your authentication middleware.

public function handle($request, Closure $next)
{
    if ($this->auth->guest())
    {
        if ($request->ajax())
        {
            return response('Unauthorized.', 401); // Or, return a response that causes client side js to redirect to '/routesPrefix/myIdp1/login'
        }
        else
        {
            $saml2Auth = new Saml2Auth(Saml2Auth::loadOneLoginAuthFromIpdConfig('myIdp1'));
            return $saml2Auth->login(URL::full());
        }
    }

    return $next($request);
}

Since Lumen 5.3, you can change your unauthenticated method in app/Exceptions/Handler.php.

protected function unauthenticated($request, AuthenticationException $exception)
{
    if ($request->expectsJson())
    {
        return response()->json(['error' => 'Unauthenticated.'], 401); // Or, return a response that causes client side js to redirect to '/routesPrefix/myIdp1/login'
    }

    $saml2Auth = new Saml2Auth(Saml2Auth::loadOneLoginAuthFromIpdConfig('myIdp1'));
    return $saml2Auth->login('/my/redirect/path');
}

For login requests that come through redirects to the login route, 'routesPrefix/myidp1/login', the default login call does not pass a redirect URL to the Saml login request. That login argument is useful because the ACS handler can gets that value (passed back from the IDP as RelayPath) and by default will redirect there. To pass the redirect URL from the controller login, extend the Saml2Controller class and implement your own login() function. Set the saml2_settings value saml2_controller to be your extended class so that the routes will direct requests to your controller instead of the default.
E.g.
saml_settings.php

    'saml2_controller' => 'App\Http\Controllers\MyNamespace\MySaml2Controller'

MySaml2Controller.php

use Ibpavlov\Saml2\Http\Controllers\Saml2Controller;

class MySaml2Controller extends Saml2Controller
{
    public function login()
    {
        $loginRedirect = '...'; // Determine redirect URL
        $this->saml2Auth->login($loginRedirect);
    }
}

After login is called, the user will be redirected to the IDP login page. Then the IDP, which you have configured with an endpoint the library serves, will call back, e.g. /myidp1/acs or /routesPrefix/myidp1/acs. That will process the response and fire an event when ready. The next step for you is to handle that event. You just need to login the user or refuse.

 Event::listen('Ibpavlov\Saml2\Events\Saml2LoginEvent', function (Saml2LoginEvent $event) {
            $messageId = $event->getSaml2Auth()->getLastMessageId();
            // Add your own code preventing reuse of a $messageId to stop replay attacks

            $user = $event->getSaml2User();
            $userData = [
                'id' => $user->getUserId(),
                'attributes' => $user->getAttributes(),
                'assertion' => $user->getRawSamlAssertion()
            ];
             $LumenUser = //find user by ID or attribute
             //if it does not exist create it and go on  or show an error message
             Auth::login($LumenUser);
        });

Auth persistence

Be careful about necessary Lumen middleware for Auth persistence in Session.

For exemple, it can be:

# in App\Http\Kernel
protected $middlewareGroups = [
        'web' => [
	    ...
	],
	'api' => [
            ...
        ],
        'saml' => [
            \App\Http\Middleware\EncryptCookies::class,
            \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
            \Illuminate\Session\Middleware\StartSession::class,
        ],

And in config/saml2_settings.php :

    /**
     * which middleware group to use for the saml routes
     * Lumen 5.2 will need a group which includes StartSession
     */
    'routesMiddleware' => ['saml'],

Log out

Now there are two ways the user can log out.

1 - By logging out in your app: In this case you 'should' notify the IDP first so it closes global session.
2 - By logging out of the global SSO Session. In this case the IDP will notify you on /myidp1/slo endpoint (already provided), if the IDP supports SLO

For case 1 call Saml2Auth::logout(); or redirect the user to the logout route, e.g. 'myidp1_logout' which does just that. Do not close the session immediately as you need to receive a response confirmation from the IDP (redirection). That response will be handled by the library at /myidp1/sls and will fire an event for you to complete the operation.

For case 2 you will only receive the event. Both cases 1 and 2 receive the same event.

Note that for case 2, you may have to manually save your session to make the logout stick (as the session is saved by middleware, but the OneLogin library will redirect back to your IDP before that happens)

        Event::listen('Ibpavlov\Saml2\Events\Saml2LogoutEvent', function ($event) {
            Auth::logout();
            Session::save();
        });

That's it. Feel free to ask any questions, make PR or suggestions, or open Issues.