OpenID Connect Client for Flow Framework

This Flow package provides an OpenID Connect (OIDC) client SDK. OpenID Connect is an authentication layer built on top of OAuth 2.0. While OAuth is intended to be used for authorization, OpenID Connect is responsible for authentication – that is, verifying the identity of a human or machine user, commonly called "entity".

OIDC provides profile information about an authenticated user through an identity token, which is encoded as a secure JSON Web Token (JWT). JWTs are easy to handle in client- and server-side applications. The data contained in the ID token is usually signed and can optionally be encrypted.

Feature Overview

This plugin acts as a Flow authentication provider. It allows you to authenticate and authorize users using a browser and machine users (for example, other applications) communicating with your application via an API.

A few feature highlights of this package:

• drop-in replacement for other authentication methods for Flow applications or Neos websites
• OIDC auto-discovery support for minimal configuration
• support for multiple OIDC services (servers) within one application
• integration into Flow's session management based on JWT cookies
• mapping of Flow user roles from claims
• automatic JWT signature verification
• authentication via bearer access token
• automatic refresh of expired access tokens
• easy access to ID tokens through the Flow account model
• command line support for testing

Terms and Background

Before deploying OpenID Connect for your application, you should get familiar with the concepts. As a quick reminder, here are some terms you should know about.

Authentication vs. Authorization

Authentication is the process of confirming the identity of a person or other entity. A user will need to proof her identity – for example by providing a username and password.

Authorization refers to the process of verifying what actions entities are allowed to perform or which information they may access. In this cases it's not about the identity, but only about the permissions.

More often than not, you will want to combine these concepts for your application – but it's important to know the difference.

Identity Provider

An Identity Provider is handling the authentication and authorization process for you. Popular identity providers are Google, Facebook, Microsoft, paid services like Auth0, or dedicated setups like gluu. Identity providers may implement methods like username / password authentication or advanced methods, like multi-factor authentication.

Identity Token

The ID Token is provided as part of a JSON Web Token (JWT). It contains the identity data of the authenticated entity. A JWT consists of a header, body and signature.

Claims

The ID Token provides information about an entity (for example, a user). The different bits of information could be a name, a URL pointing to a profile picture, or an email address. These information bits are called "claims". Because they are signed, as part of the JWT, you can trust them without having to specifically ask a central API.

Bearer Access Token

The access token gives the holder access to a specific service or other resource. That means, whoever owns this access token is permitted to access the resources for which the token was issued.

Access tokens usually have a limited lifetime and are issued for a specific scope.

Audience

The audience is the application or service which you want to protect with OpenId Connect. It is the intended recipient of the token and usually identified by an address, like https://my-application.example.com. However, like with XML namespaces, that address does not really have to exist and is just used as an identifier.

Requirements

In order to use this plugin you need:

• an OIDC Identity Provider which provides auto discovery
• an application (such as Neos), based on Flow 6.0 or higher

Installation

The Flownative OpenID Connect plugin is installed via Composer:

composer require flownative/openidconnect-client

Usage Scenarios

Here are a few examples for using this plugin:

Authenticate web users

For example, use this plugin to authenticate and authorize users for the Neos backend.

What you need is:

• configure the discovery URI for your identity provider
• configure Flow to use this plugin as an authentication provider
• configure the HTTP chain to manage JWT session cookies
• configure Flow and this plugin to set user roles

You will use the Authorization Code Grant for this type of application.

Authenticate applications

For example, use this plugin to authenticate and authorize your other third party's services accessing an API provided by your application.

• configure the discovery URI for your identity provider
• configure Flow to use this plugin as a (second) authentication provider
• configure the HTTP chain to manage JWT session cookies
• configure Flow and this plugin to set user roles
• protect your API methods and evaluate further permissions obtained from the identity token

You will use the Client Credentials Grant for this type of application.

OpenID Connect Discovery

Identity providers usually expose OIDC discovery documents at a certain URL (for example, https://id.example.com/.well-known/openid-configuration). The Flownative OIDC client plugin uses discovery to configure authorization, token and user info endpoints, the JWKs location, supported scopes and more.

Configure the discovery endpoint as follows:

Flownative:
  OpenIdConnect:
    Client:
      services:
        myService:
          options:
            discoveryUri: 'https://id.example.com/.well-known/openid-configuration'            

You can check if discovery is working by running the following command from a terminal:

./flow oidc:discover myService

+---------------------------------------+-----------------------------------------------------------+
| Option                                | Value                                                     |
+---------------------------------------+-----------------------------------------------------------+
| issuer                                | https://id.example.com/                                   |
| authorization_endpoint                | https://id.example.com/authorize                          |
| token_endpoint                        | https://id.example.com/oauth/token                        |
| userinfo_endpoint                     | https://id.example.com/userinfo                           |
| mfa_challenge_endpoint                | https://id.example.com/mfa/challenge                      |
| jwks_uri                              | https://id.example.com/.well-known/jwks.json              |
| registration_endpoint                 | https://id.example.com/oidc/register                      |
| revocation_endpoint                   | https://id.example.com/oauth/revoke                       |
| scopes_supported                      | array (                                                   |
|                                       |   0 => 'openid',                                          |
|                                       |   1 => 'profile',                                         |
|                                       |   2 => 'offline_access',                                  |
|                                       |   3 => 'name',                                            |
|                                       |   4 => 'given_name',                                      |
|                                       |   5 => 'family_name',                                     |
|                                       |   6 => 'nickname',                                        |
|                                       |   7 => 'email',                                           |
|                                       |   8 => 'email_verified',                                  |
|                                       |   9 => 'picture',                                         |
|                                       |   10 => 'created_at',                                     |
|                                       |   11 => 'identities',                                     |
|                                       |   12 => 'phone',                                          |
|                                       |   13 => 'address',                                        |
|                                       | )                                                         |
| response_types_supported              | array (                                                   |
|                                       |   0 => 'code',                                            |
|                                       |   1 => 'token',                                           |
|                                       |   2 => 'id_token',                                        |
|                                       |   3 => 'code token',                                      |
|                                       |   4 => 'code id_token',                                   |
|                                       |   5 => 'token id_token',                                  |
|                                       |   6 => 'code token id_token',                             |
|                                       | )                                                         |
| code_challenge_methods_supported      | array (                                                   |
|                                       |   0 => 'S256',                                            |
|                                       |   1 => 'plain',                                           |
|                                       | )                                                         |
| response_modes_supported              | array (                                                   |
|                                       |   0 => 'query',                                           |
|                                       |   1 => 'fragment',                                        |
|                                       |   2 => 'form_post',                                       |

…

Authorization Code Grant

The Authorization Code Grant is used for authenticating users using a web browser. The typical application flow goes like this:

1. a user tries to access a protected page (controller action)
2. Flow checks if the user has a cookie containing a valid JWT
3. no valid JWT, so redirect to the identity provider's login page
4. user logs in and is redirected back to Flow
5. an authorization code is passed to Flow and Flow uses that to obtain an access token behind the scenes
6. a JWT is extracted from the access token and sent to the browser as a cookie
7. during the following web requests, the browser sends the cookie and Flow recognizes the user as being authenticated

The Flow application needs a client identifier and a client secret so it can request authorization codes from the identity provider.

Here's an example configuration which enables OIDC authentication for a Neos backend. Please note that this is a proof-of-concept. This integration needs further configuration and custom implementation to be production-ready:

Flownative:
  OpenIdConnect:
    Client:
      services:
        test:
          options:
            discoveryUri: 'https://id.example.com/.well-known/openid-configuration'
            clientId: 'abcdefghijklmnopqrstuvwxyz01234567890'
            clientSecret: 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU2Nzg5MA=='
      middleware:
        cookie:      
          # For testing purposes allow cookies without HTTPS:
          secure: false

Neos:
  Flow:
    security:
      authentication:
        providers:
          # Re-use the Neos authentication provider so we automatically get the right
          # request patterns:
          'Neos.Neos:Backend':
            label: 'Neos Backend (OIDC)'
            provider: 'Flownative\OpenIdConnect\Client\Authentication\OpenIdConnectProvider'
            providerOptions:
              audience: 'https://www.example.com/neos'
              roles: ['Neos.Neos:Administrator']
              accountIdentifierTokenValueName: 'sub'
              serviceName: 'test'
            token: 'Flownative\OpenIdConnect\Client\Authentication\OpenIdConnectToken'
            entryPoint: 'Flownative\OpenIdConnect\Client\Authentication\OpenIdConnectEntryPoint'
            entryPointOptions:
              serviceName: 'test'
              scopes: ['sub', 'profile', 'name']

        authenticationStrategy: atLeastOneToken

Without further programming you need to manually create a Neos user which has the same username as the one provided in the "sub" claim by the OIDC identity provider.

Client Credentials Grant

Client Credentials Grant is a bit simpler than Authorization Code Grant, but can only be used for trusted parties. Because you use long-living client credentials directly (instead of going that extra step of trading an access token for an authorization code), you cannot use this type of grant in a browser, because the credentials would not be safe there.

Here's an example consisting of two parts: An application providing an API and a second one consuming that API.

The URI used as the "audience" string is only a URI by convention. In fact, it can be any other string, but must be recognized by your identity provider.

The following configuration is used in the Flow application using the API:

Flownative:
  OpenIdConnect:
    Client:
      services:
        test:
          options:
            discoveryUri: 'https://id.example.com/.well-known/openid-configuration'
            clientId: 'abcdefghijklmnopqrstuvwxyz01234567890'
            clientSecret: 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU2Nzg5MA=='
            additionalParameters:
              audience: 'http://yourapp.localbeach.net/api/v1'

Somewhere in your application you might have a service class which wraps communication with the API. It may look like this (some code omitted for brevity):

class BillingService
{
    public function sendAuthenticatedRequest(string $relativeUri, string $method = 'GET', array $bodyFields = []): ResponseInterface
    {
        $openIdConnectClient = new OpenIdConnectClient('test');

        $accessToken = $openIdConnectClient->getAccessToken(
            'test',
            $this->clientId,
            $this->clientSecret,
            '',
            Authorization::GRANT_CLIENT_CREDENTIALS,
            $this->additionalParameters
        );

        $httpClient = new Client(['allow_redirects' => false]);
        return $httpClient->request(
            $method,
            trim($this->apiBaseUri, '/') . '/' . $relativeUri,
            [
                'headers' =>
                    [
                        'Content-Type' => 'application/json',
                        'Authorization' => 'Bearer ' . $accessToken->getToken()
                    ],
                'body' => ($bodyFields !== [] ? \GuzzleHttp\json_encode($bodyFields) : '')
            ]
        );
    }
}

The important bit is that your code uses the OpenID Connect Client to retrieve an access token and then sends that as part of an authorization header to the API.

The application providing the API needs the following configuration, likely using a different client id and secret than the consuming app:

Flownative:
  OpenIdConnect:
    Client:
      services:
        test:
          options:
            discoveryUri: 'https://id.example.com/.well-known/openid-configuration'
            clientId: 'abcdefghijklmnopqrstuvwxyz01234567890'
            clientSecret: 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU2Nzg5MA=='

A base controller in your application providing the API may look like this:

abstract class AbstractApiController extends ActionController
{
    /**
     * @Flow\Inject
     * @var Context
     */
    protected $securityContext;

    /**
     * @var IdentityToken|null
     */
    protected $identityToken;

    /**
     * @return void
     */
    public function initializeAction()
    {
        parent::initializeAction();

        $account = $this->securityContext->getAccount();
        $identityToken = $account->getCredentialsSource();
        if ($identityToken instanceof IdentityToken) {
            $this->identityToken = $identityToken;
        }
    }
}

Roles from Identity Token

Instead of specifying the Flow authentication roles directly, the provider can extract the roles from the identity token values. The roles provided by the token must have the same identifier which is used in Flow's policy configuration.

Given that the identity token provides a claim called "https://flownative.com/roles", you may configure the provider as follows:

…
        security:
          authentication:
            providers:
              'Flownative.OpenIdConnect.Client:OidcProvider':
                label: 'OpenID Connect'
                provider: 'Flownative\OpenIdConnect\Client\Authentication\OpenIdConnectProvider'
                providerOptions:
                  rolesFromClaims:
                    - 'https://flownative.com/roles'
                  …
 

When a user logs in and her identity token has a value "https://flownative.com/roles" containing an array of Flow role identifiers, the OpenID Connect provider will automatically assign these roles to the transient account.

You may specify multiple claim names which are all considered for compiling a list of roles.

Check logs for hints if things are not working as expected.

Roles from an Existing Account

As a third option, roles can be used from an existing account whose account identifier matches a given claim of the identity token. Or put differently: if there's an account with the same username which is provided by the identity token, roles of that (persisted) account can be used.

Given that the identity token provides a claim called "email" and that an account (for example, a Neos user account) exists using an email address as its account identifier, you may configure the provider as follows:

…
        security:
          authentication:
            providers:
              'Flownative.OpenIdConnect.Client:OidcProvider':
                label: 'OpenID Connect'
                provider: 'Flownative\OpenIdConnect\Client\Authentication\OpenIdConnectProvider'
                providerOptions:
                  accountIdentifierTokenValueName: 'email'
                  addRolesFromExistingAccount: true
                  …
 

When a user logs in and her identity token has a value "email" containing "alice@example.com", the OpenID Connect provider will automatically assign any roles which are assigned to a Flow account with the same account identifier.

You may mix "rolesFromClaims" with "addRolesFromExistingAccount". In that case roles from claims and existing accounts will be merged.

Again, check logs for hints if things are not working as expected.

More Authentication Provider Options

When you are using the OpenID Connect Authentication Provider, you can provide options for additional security measures.

Audience Pinning

It is recommended to specify the "audience" identifier of your application. That way, tokens issued by your identity provider will only accepted for authentication, if the audience string of the token ("aud") matches the string configured in your application. Without this configuration, your application would accept any token of your identity provider, if it has a valid signature and comes with the correct roles claim.

…
        security:
          authentication:
            providers:
              'Flownative.OpenIdConnect.Client:OidcProvider':
                label: 'OpenID Connect'
                provider: 'Flownative\OpenIdConnect\Client\Authentication\OpenIdConnectProvider'
                providerOptions:
                  audience: 'https://www.example.com/my-application'
                  …

More about OpenID Connect

See also:

https://openid.net/specs/openid-connect-basic-1_0.html https://connect2id.com/learn/openid-connect

Example Configuration for Neos CMS

With the following configuration, you can use OIDC for authentication of Neos CMS backend users. OIDC is only used for authentication (not authorization). For this to work, the identity token must provide the user's email address via the token value "email" and a Neos user with this email address (as username) must exist.

Flownative:
  OpenIdConnect:
    Client:
      services:
        neos:
          options:
            discoveryUri: '%env:OIDC_DISCOVERY_URI%'
            clientId: '%env:OIDC_CLIENT_ID%'
            clientSecret: '%env:OIDC_CLIENT_SECRET%'
            additionalParameters:
              audience: '%env:OIDC_AUDIENCE%'

      middleware:
        authenticationProviderName: 'Neos.Neos:Backend'

Neos:
  Flow:
    security:
      authentication:
        providers:
          'Neos.Neos:Backend':
            label: 'OpenID Connect'
            provider: 'Flownative\OpenIdConnect\Client\Authentication\OpenIdConnectProvider'

            requestPatterns:
              'Neos.Neos:BackendControllers':
                pattern: 'ControllerObjectName'
                patternOptions:
                  controllerObjectNamePattern: 'Neos\Neos\Controller\.*'
              'Neos.Neos:ServiceControllers':
                pattern: 'ControllerObjectName'
                patternOptions:
                  controllerObjectNamePattern: 'Neos\Neos\Service\.*'

            providerOptions:
              addRolesFromExistingAccount: true
              accountIdentifierTokenValueName: 'email'
              jwtCookieName: 'flownative_oidc_jwt'
              serviceName: 'neos'
            token: 'Flownative\OpenIdConnect\Client\Authentication\OpenIdConnectToken'
            entryPoint: 'Flownative\OpenIdConnect\Client\Authentication\OpenIdConnectEntryPoint'
            entryPointOptions:
              serviceName: 'neos'
              scope: 'profile email'

        authenticationStrategy: oneToken
    session:
      inactivityTimeout: 14400

Credits and Support

This library was developed by Robert Lemke / Flownative. Feel free to suggest new features, report bugs or provide bug fixes in our Github project.

If you'd like us to develop a new feature or need help implementing OIDC in your project, please get in touch with Robert.