Doorkeeper::OpenidConnect

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This library implements an OpenID Connect authentication provider for Rails applications on top of the Doorkeeper OAuth 2.0 framework.

OpenID Connect is a single-sign-on and identity layer with a growing list of server and client implementations. If you're looking for a client in Ruby check out omniauth_openid_connect.

Table of Contents

• Status
  • Known Issues
  • Example Applications
• Installation
• Configuration
  • Scopes
  • Claims
  • Routes
  • Nonces
  • Internationalization (I18n)
• Development
• License
• Sponsors

Status

The following parts of OpenID Connect Core 1.0 are currently supported:

• Authentication using the Authorization Code Flow
• Authentication using the Implicit Flow
• Requesting Claims using Scope Values
• UserInfo Endpoint
• Normal Claims
• OAuth 2.0 Form Post Response Mode

In addition we also support most of OpenID Connect Discovery 1.0 for automatic configuration discovery.

Take a look at the DiscoveryController for more details on supported features.

Known Issues

• Doorkeeper's API mode (Doorkeeper.configuration.api_only) is not properly supported yet

Example Applications

• GitLab (original MR)
• Testing app for this gem

Installation

Make sure your application is already set up with Doorkeeper.

Add this line to your application's Gemfile and run bundle install:

gem 'doorkeeper-openid_connect'

Run the installation generator to update routes and create the initializer:

rails generate doorkeeper:openid_connect:install

Generate a migration for Active Record (other ORMs are currently not supported):

rails generate doorkeeper:openid_connect:migration
rake db:migrate

If you're upgrading from an earlier version, check CHANGELOG.md for upgrade instructions.

Configuration

Make sure you've configured Doorkeeper before continuing.

Verify your settings in config/initializers/doorkeeper.rb:

• resource_owner_authenticator

  • This callback needs to returns a falsey value if the current user can't be determined:

    resource_owner_authenticator do
      if current_user
        current_user
      else
        redirect_to(new_user_session_url)
        nil
      end
    end
    

• grant_flows

  • If you want to use id_token or id_token token response types you need to add implicit_oidc to grant_flows:

    grant_flows %w(authorization_code implicit_oidc)
    

The following settings are required in config/initializers/doorkeeper_openid_connect.rb:

• issuer

  • Identifier for the issuer of the response (i.e. your application URL). The value is a case sensitive URL using the https scheme that contains scheme, host, and optionally, port number and path components and no query or fragment components.
  • You can either pass a string value, or a block to generate the issuer dynamically based on the resource_owner and application or request passed to the block.

• subject

  • Identifier for the resource owner (i.e. the authenticated user). A locally unique and never reassigned identifier within the issuer for the end-user, which is intended to be consumed by the client. The value is a case-sensitive string and must not exceed 255 ASCII characters in length.

  • The database ID of the user is an acceptable choice if you don't mind leaking that information.

  • If you want to provide a different subject identifier to each client, use pairwise subject identifier with configurations like below.

    # config/initializers/doorkeeper_openid_connect.rb
    Doorkeeper::OpenidConnect.configure do
    # ...
      subject_types_supported [:pairwise]
    
      subject do |resource_owner, application|
        Digest::SHA256.hexdigest("#{resource_owner.id}#{URI.parse(application.redirect_uri).host}#{'your_secret_salt'}")
      end
    # ...
    end
    

• signing_key

  • Private key to be used for JSON Web Signature.
  • You can generate a private key with the openssl command, see e.g. Generate an RSA keypair using OpenSSL.
  • You should not commit the key to your repository, but use an external file (in combination with File.read) and/or the dotenv-rails gem (in combination with ENV[...]).

• signing_algorithm

  • The encryption type of the private key which defaults to :rs256. The list of supported algorithms can be found here

• resource_owner_from_access_token

  • Defines how to translate the Doorkeeper access token to a resource owner model.

The following settings are optional, but recommended for better client compatibility:

• auth_time_from_resource_owner
  • Returns the time of the user's last login, this can be a Time, DateTime, or any other class that responds to to_i
  • Required to support the max_age parameter and the auth_time claim.
• reauthenticate_resource_owner
  • Defines how to trigger reauthentication for the current user (e.g. display a password prompt, or sign-out the user and redirect to the login form).
  • Required to support the max_age and prompt=login parameters.
  • The block is executed in the controller's scope, so you have access to methods like params, redirect_to etc.
• select_account_for_resource_owner
  • Defines how to trigger account selection to choose the current login user.
  • Required to support the prompt=select_account parameter.
  • The block is executed in the controller's scope, so you have access to methods like params, redirect_to etc.

The following settings are optional:

• expiration

  • Expiration time after which the ID Token must not be accepted for processing by clients.
  • The default is 120 seconds

• protocol

  • The protocol to use when generating URIs for the discovery endpoints.
  • The default is https for production, and http for all other environments
  • Note that the OIDC specification mandates HTTPS, so you shouldn't change this for production environments unless you have a really good reason!

• end_session_endpoint

  • The URL that the user is redirected to after ending the session on the client.
  • Used by implementations like IdentityModel/oidc-client-js.
  • The block is executed in the controller's scope, so you have access to your route helpers.

• discovery_url_options

  • The URL options for every available endpoint to use when generating the endpoint URL in the discovery response. Available endpoints: authorization, token, revocation, introspection, userinfo, jwks, webfinger.

  • This option requires option keys with an available endpoint and URL options as value.

  • The default is to use the request host, just like all the other URLs in the discovery response.

  • This is useful when you want endpoints to use a different URL than other requests. For example, if your Doorkeeper server is behind a firewall with other servers, you might want other servers to use an "internal" URL to communicate with Doorkeeper, but you want to present an "external" URL to end-users for authentication requests. Note that this setting does not actually change the URL that your Doorkeeper server responds on - that is outside the scope of Doorkeeper.

    # config/initializers/doorkeeper_openid_connect.rb
    Doorkeeper::OpenidConnect.configure do
    # ...
      discovery_url_options do |request|
        {
          authorization: { host: 'host.example.com' },
          jwks:          { protocol: request.ssl? ? :https : :http }
        }
      end
    # ...
    end
    

Scopes

To perform authentication over OpenID Connect, an OAuth client needs to request the openid scope. This scope needs to be enabled using either optional_scopes in the global Doorkeeper configuration in config/initializers/doorkeeper.rb, or by adding it to any OAuth application's scope attribute.

Note that any application defining its own scopes won't inherit the scopes defined in the initializer, so you might have to update existing applications as well.

See Using Scopes in the Doorkeeper wiki for more information.

Claims

Claims can be defined in a claims block inside config/initializers/doorkeeper_openid_connect.rb:

Doorkeeper::OpenidConnect.configure do
  claims do
    claim :email do |resource_owner|
      resource_owner.email
    end

    claim :full_name do |resource_owner|
      "#{resource_owner.first_name} #{resource_owner.last_name}"
    end

    claim :preferred_username, scope: :openid do |resource_owner, scopes, access_token|
      # Pass the resource_owner's preferred_username if the application has
      # `profile` scope access. Otherwise, provide a more generic alternative.
      scopes.exists?(:profile) ? resource_owner.preferred_username : "summer-sun-9449"
    end

    claim :groups, response: [:id_token, :user_info] do |resource_owner|
      resource_owner.groups
    end
  end
end

Each claim block will be passed:

• the resource_owner, which is the return value of resource_owner_authenticator in your initializer
• the scopes granted by the access token, which is an instance of Doorkeeper::OAuth::Scopes
• the access_token itself, which is an instance of Doorkeeper::AccessToken

By default all custom claims are only returned from the UserInfo endpoint and not included in the ID token. You can optionally pass a response: keyword with one or both of the symbols :id_token or :user_info to specify where the claim should be returned.

You can also pass a scope: keyword argument on each claim to specify which OAuth scope should be required to access the claim. If you define any of the defined Standard Claims they will by default use their corresponding scopes (profile, email, address and phone), and any other claims will by default use the profile scope. Again, to use any of these scopes you need to enable them as described above.

Routes

The installation generator will update your config/routes.rb to define all required routes:

Rails.application.routes.draw do
  use_doorkeeper_openid_connect
  # your routes
end

This will mount the following routes:

GET   /oauth/userinfo
POST  /oauth/userinfo
GET   /oauth/discovery/keys
GET   /.well-known/openid-configuration
GET   /.well-known/webfinger

With the exception of the hard-coded /.well-known paths (see RFC 5785) you can customize routes in the same way as with Doorkeeper, please refer to this page on their wiki.

Nonces

To support clients who send nonces you have to tweak Doorkeeper's authorization view so the parameter is passed on.

If you don't already have custom templates, run this generator in your Rails application to add them:

rails generate doorkeeper:views

Then tweak the template as follows:

--- i/app/views/doorkeeper/authorizations/new.html.erb
+++ w/app/views/doorkeeper/authorizations/new.html.erb
@@ -26,6 +26,7 @@
       <%= hidden_field_tag :state, @pre_auth.state %>
       <%= hidden_field_tag :response_type, @pre_auth.response_type %>
       <%= hidden_field_tag :scope, @pre_auth.scope %>
+      <%= hidden_field_tag :nonce, @pre_auth.nonce %>
       <%= submit_tag t('doorkeeper.authorizations.buttons.authorize'), class: "btn btn-success btn-lg btn-block" %>
     <% end %>
     <%= form_tag oauth_authorization_path, method: :delete do %>
@@ -34,6 +35,7 @@
       <%= hidden_field_tag :state, @pre_auth.state %>
       <%= hidden_field_tag :response_type, @pre_auth.response_type %>
       <%= hidden_field_tag :scope, @pre_auth.scope %>
+      <%= hidden_field_tag :nonce, @pre_auth.nonce %>
       <%= submit_tag t('doorkeeper.authorizations.buttons.deny'), class: "btn btn-danger btn-lg btn-block" %>
     <% end %>
   </div>

Internationalization (I18n)

We use Rails locale files for error messages and scope descriptions, see config/locales/en.yml. You can override these by adding them to your own translations in config/locale.

Development

Run bundle install to setup all development dependencies.

To run all specs:

bundle exec rake spec

To generate and run migrations in the test application:

bundle exec rake migrate

To run the local engine server:

bundle exec rake server

By default, the latest Rails version is used. To use a specific version run:

rails=4.2.0 bundle update

License

Doorkeeper::OpenidConnect is released under the MIT License.

Sponsors

Initial development of this project was sponsored by PlayOn! Sports.