GitLab

Tested Versions#

• Authelia
  • v4.38.0
• GitLab CE
  • 16.9.0

Before You Begin#

Common Notes#

1. The OpenID Connect 1.0 client_id parameter:
   1. This must be a unique value for every client.
   2. The value used in this guide is merely for readability and demonstration purposes and you should not use this value in production and should instead utilize the How do I generate a client identifier or client secret? FAQ. We recommend 64 random characters but you can use any arbitrary value that meets the other criteria.
   3. This must only contain RFC3986 Unreserved Characters.
   4. This must be no more than 100 characters in length.
2. The OpenID Connect 1.0 client_secret parameter:
   1. The value used in this guide is merely for demonstration purposes and you should absolutely not use this value in production and should instead utilize the How do I generate a client identifier or client secret? FAQ.
   2. This string may be stored as plaintext in the Authelia configuration but this behaviour is deprecated and is not guaranteed to be supported in the future. See the Plaintext guide for more information.
   3. When the secret is stored in hashed form in the Authelia configuration (heavily recommended), the cost of hashing can, if too great, cause timeouts for clients. See the Tuning the work factors guide for more information.
3. The configuration example for Authelia:
   1. Only contains an example configuration for the client registration and you MUST also configure the required elements from the OpenID Connect 1.0 Provider Configuration guide.
   2. Only contains a small portion of all of the available options for a registered client and users may wish to configure portions that are not part of this guide or configure them differently, as such it’s important to both familiarize yourself with the other options available and the effect of each of the options configured in this section by looking at the OpenID Connect 1.0 Clients Configuration guide.

Assumptions#

This example makes the following assumptions:

• Application Root URL: https://gitlab.example.com/
• Authelia Root URL: https://auth.example.com/
• Client ID: gitlab
• Client Secret: insecure_secret

Configuration#

Authelia#

Important Note: This configuration assumes you’ve configured the client_auth_method in GitLab as per below. If you have not done this the default in GitLab will require the token_endpoint_auth_method changes to client_secret_post.

The following YAML configuration is an example Authelia client configuration for use with GitLab which will operate with the application example:

identity_providers:
  oidc:
    ## The other portions of the mandatory OpenID Connect 1.0 configuration go here.
    ## See: https://www.authelia.com/c/oidc
    clients:
      - client_id: 'gitlab'
        client_name: 'GitLab'
        client_secret: '$pbkdf2-sha512$310000$c8p78n7pUMln0jzvd4aK4Q$JNRBzwAo0ek5qKn50cFzzvE9RXV88h1wJn5KGiHrD0YKtZaR/nCb2CJPOsKaPK0hjf.9yHxzQGZziziccp6Yng'  # The digest of 'insecure_secret'.
        public: false
        authorization_policy: 'two_factor'
        redirect_uris:
          - 'https://gitlab.example.com/users/auth/openid_connect/callback'
        scopes:
          - 'openid'
          - 'profile'
          - 'groups'
          - 'email'
        userinfo_signed_response_alg: 'none'
        token_endpoint_auth_method: 'client_secret_basic'

Application#

To configure GitLab to utilize Authelia as an OpenID Connect 1.0 Provider:

1. Add the Omnibus OpenID Connect 1.0 OmniAuth configuration to gitlab.rb:

gitlab_rails['omniauth_providers'] = [
  {
    name: "openid_connect",
    label: "Authelia",
    icon: "https://www.authelia.com/images/branding/logo-cropped.png",
    args: {
      name: "openid_connect",
      strategy_class: "OmniAuth::Strategies::OpenIDConnect",
      issuer: "https://auth.example.com",
      discovery: true,
      scope: ["openid","profile","email","groups"],
      client_auth_method: "basic",
      response_type: "code",
      response_mode: "query",
      uid_field: "preferred_username",
      send_scope_to_token_endpoint: true,
      pkce: true,
      client_options: {
        identifier: "gitlab",
        secret: "insecure_secret",
        redirect_uri: "https://gitlab.example.com/users/auth/openid_connect/callback"
      }
    }
  }
]

Groups#

GitLab offers group mapping options with OpenID Connect 1.0, shamefully it’s only for paid plans. However see the guide on how to configure it on their end.

Alternatively if GitLab is associated with LDAP you can use that as a group source, and you can configure a policy on Authelia to restrict which resource owners are allowed access to the client for free via a custom authorization_policy value.

See Also#

• GitLab OpenID Connect OmniAuth Documentation