OmniAuth

Tier: Free, Premium, Ultimate Offering: Self-managed

Users can sign in to GitLab by using their credentials from Twitter, GitHub, and other popular services. OmniAuth is the Rack framework that GitLab uses to provide this authentication.

When configured, additional sign-in options are displayed on the sign-in page.

Supported providers

GitLab supports the following OmniAuth providers.

Provider documentation OmniAuth provider name
AliCloud alicloud
Atlassian atlassian_oauth2
Auth0 auth0
AWS Cognito cognito
Azure v2 azure_activedirectory_v2
Azure v1 azure_oauth2
Bitbucket Cloud bitbucket
DingTalk dingtalk
Facebook facebook
Generic OAuth 2.0 oauth2_generic
GitHub github
GitLab.com gitlab
Google google_oauth2
JWT jwt
Kerberos kerberos
OpenID Connect openid_connect
Salesforce salesforce
SAML saml
Shibboleth shibboleth
Twitter twitter

Configure common settings

Before you configure the OmniAuth provider, configure the settings that are common for all providers.

Linux package, Docker, and self-compiled Helm chart Description Default value
allow_single_sign_on allowSingleSignOn List of providers that automatically create a GitLab account. The provider names are available in the OmniAuth provider name column in the supported providers table. false, which means that signing in using your OmniAuth provider account without a pre-existing GitLab account is not allowed. You must create a GitLab account first, and then connect it to your OmniAuth provider account through your profile settings.
auto_link_ldap_user autoLinkLdapUser Creates an LDAP identity in GitLab for users that are created through an OmniAuth provider. You can enable this setting if you have LDAP integration enabled. Requires the uid of the user to be the same in both LDAP and the OmniAuth provider. false
block_auto_created_users blockAutoCreatedUsers Places automatically-created users in a Pending approval state (unable to sign in) until they are approved by an administrator. true. If you set the value to false, make sure you define providers that you can control, like SAML or Google. Otherwise, any user on the internet can sign in to GitLab without an administrator’s approval.

Configure initial settings

To change the OmniAuth settings:

Linux package (Omnibus)
  1. Edit /etc/gitlab/gitlab.rb:

    # CAUTION!
    # This allows users to sign in without having a user account first. Define the allowed providers
    # using an array, for example, ["saml", "twitter"], or as true/false to allow all providers or none.
    # User accounts will be created automatically when authentication was successful.
    gitlab_rails['omniauth_allow_single_sign_on'] = ['saml', 'twitter']
    gitlab_rails['omniauth_auto_link_ldap_user'] = true
    gitlab_rails['omniauth_block_auto_created_users'] = true
    
  2. Save the file and reconfigure GitLab:

    sudo gitlab-ctl reconfigure
    
Helm chart (Kubernetes)
  1. Export the Helm values:

    helm get values gitlab > gitlab_values.yaml
    
  2. Edit gitlab_values.yaml, and update the omniauth section under globals.appConfig:

    global:
      appConfig:
        omniauth:
          enabled: true
          allowSingleSignOn: ['saml', 'twitter']
          autoLinkLdapUser: false
          blockAutoCreatedUsers: true
    

    For more details, see the globals documentation.

  3. Save the file and apply the new values:

    helm upgrade -f gitlab_values.yaml gitlab gitlab/gitlab
    
Docker
  1. Edit docker-compose.yml:

    version: "3.6"
    services:
      gitlab:
        environment:
          GITLAB_OMNIBUS_CONFIG: |
            gitlab_rails['omniauth_allow_single_sign_on'] = ['saml', 'twitter']
            gitlab_rails['omniauth_auto_link_ldap_user'] = true
            gitlab_rails['omniauth_block_auto_created_users'] = true
    
  2. Save the file and restart GitLab:

    docker compose up -d
    
Self-compiled (source)
  1. Edit /home/git/gitlab/config/gitlab.yml:

    ## OmniAuth settings
    omniauth:
      # Allow sign-in by using Twitter, Google, etc. using OmniAuth providers
      # Versions prior to 11.4 require this to be set to true
      # enabled: true
    
      # CAUTION!
      # This allows users to sign in without having a user account first. Define the allowed providers
      # using an array, for example, ["saml", "twitter"], or as true/false to allow all providers or none.
      # User accounts will be created automatically when authentication was successful.
      allow_single_sign_on: ["saml", "twitter"]
    
      auto_link_ldap_user: true
    
      # Locks down those users until they have been cleared by the admin (default: true).
      block_auto_created_users: true
    
  2. Save the file and restart GitLab:

    # For systems running systemd
    sudo systemctl restart gitlab.target
    
    # For systems running SysV init
    sudo service gitlab restart
    

After configuring these settings, you can configure your chosen provider.

Per-provider configuration

History

If allow_single_sign_on is set, GitLab uses one of the following fields returned in the OmniAuth auth_hash to establish a username in GitLab for the user signing in, choosing the first that exists:

  • username.
  • nickname.
  • email.

You can create GitLab configuration on a per-provider basis, which is supplied to the provider using args. If you set the gitlab_username_claim variable in args for a provider, you can select another claim to use for the GitLab username. The chosen claim must be unique to avoid collisions.

Linux package (Omnibus)
gitlab_rails['omniauth_providers'] = [

  # The generic pattern for configuring a provider with name PROVIDER_NAME

  gitlab_rails['omniauth_providers'] = {
    name: "PROVIDER_NAME"
    ...
    args: { gitlab_username_claim: 'sub' } # For users signing in with the provider you configure, the GitLab username will be set to the "sub" received from the provider
  },

  # Here are examples using GitHub and Kerberos

  gitlab_rails['omniauth_providers'] = {
    name: "github"
    ...
    args: { gitlab_username_claim: 'name' } # For users signing in with GitHub, the GitLab username will be set to the "name" received from GitHub
  },
  {
    name: "kerberos"
    ...
    args: { gitlab_username_claim: 'uid' } # For users signing in with Kerberos, the GitLab username will be set to the "uid" received from Kerberos
  },
]
Self-compiled (source)
- { name: 'PROVIDER_NAME',
  ...
  args: { gitlab_username_claim: 'sub' }
}
- { name: 'github',
  ...
  args: { gitlab_username_claim: 'name' }
}
- { name: 'kerberos',
  ...
  args: { gitlab_username_claim: 'uid' }
}

Passwords for users created via OmniAuth

The Generated passwords for users created through integrated authentication guide provides an overview about how GitLab generates and sets passwords for users created with OmniAuth.

Enable OmniAuth for an existing user

If you’re an existing user, after your GitLab account is created, you can activate an OmniAuth provider. For example, if you originally signed in with LDAP, you can enable an OmniAuth provider like Twitter.

  1. Sign in to GitLab with your GitLab credentials, LDAP, or another OmniAuth provider.
  2. On the left sidebar, select your avatar.
  3. Select Edit profile.
  4. On the left sidebar, select Account.
  5. In the Connected Accounts section, select the OmniAuth provider, such as Twitter.
  6. You are redirected to the provider. After you authorize GitLab, you are redirected back to GitLab.

You can now use your chosen OmniAuth provider to sign in to GitLab.

Enable or disable sign-in with an OmniAuth provider without disabling import sources

Administrators can enable or disable sign-in for some OmniAuth providers.

note
By default, sign-in is enabled for all the OAuth providers configured in config/gitlab.yml.

To enable or disable an OmniAuth provider:

  1. On the left sidebar, at the bottom, select Admin Area.
  2. Select Settings > General.
  3. Expand Sign-in restrictions.
  4. In the Enabled OAuth authentication sources section, select or clear the checkbox for each provider you want to enable or disable.

Disable OmniAuth

OmniAuth is enabled by default. However, OmniAuth only works if providers are configured and enabled.

If OmniAuth providers are causing problems even when individually disabled, you can disable the entire OmniAuth subsystem by modifying the configuration file.

Linux package (Omnibus)
gitlab_rails['omniauth_enabled'] = false
Self-compiled (source)
omniauth:
  enabled: false
History

You can automatically link OmniAuth users with existing GitLab users if their email addresses match.

The following example enables automatic linking for the OpenID Connect provider and the Twitter OAuth provider.

Linux package (Omnibus)
gitlab_rails['omniauth_auto_link_user'] = ["openid_connect", "twitter"]
Self-compiled (source)
omniauth:
  auto_link_user: ["openid_connect", "twitter"]

This method of enabling automatic linking works for all providers except SAML. To enable automatic linking for SAML, see the SAML setup instructions.

Create an external providers list

You can define a list of external OmniAuth providers. Users who create accounts or sign in to GitLab through the listed providers do not get access to internal projects and are marked as external users.

To define the external providers list, use the full name of the provider, for example, google_oauth2 for Google. For provider names, see the OmniAuth provider name column in the supported providers table.

note
If you remove an OmniAuth provider from the external providers list, you must manually update the users that use this sign-in method so their accounts are upgraded to full internal accounts.
Linux package (Omnibus)
gitlab_rails['omniauth_external_providers'] = ['twitter', 'google_oauth2']
Self-compiled (source)
omniauth:
  external_providers: ['twitter', 'google_oauth2']

Use a custom OmniAuth provider

note
The following information only applies to self-compiled installations.

If you have to integrate with an authentication solution other than the OmniAuth providers included with GitLab, you can use a custom OmniAuth provider.

These steps are general. Read the OmniAuth provider’s documentation for the exact implementation details.

  1. Stop GitLab:

    sudo service gitlab stop
    
  2. Add the gem to your Gemfile:

    gem "omniauth-your-auth-provider"
    
  3. Install the new OmniAuth provider gem:

    sudo -u git -H bundle install --without development test mysql --path vendor/bundle --no-deployment
    

    These commands are the same as the commands for installing gems during initial installation, with --path vendor/bundle --no-deployment instead of --deployment.

  4. Start GitLab:

    sudo service gitlab start
    

Custom OmniAuth provider examples

If you have successfully set up a provider that is not already integrated with GitLab, let us know.

We can’t officially support every possible authentication mechanism available, but we’d like to at least help those with specific needs.

Keep OmniAuth user profiles up to date

You can enable profile syncing from selected OmniAuth providers. You can sync any combination of the following user attributes:

  • name
  • email
  • location

When authenticating using LDAP, the user’s name and email are always synced.

Linux package (Omnibus)
gitlab_rails['omniauth_sync_profile_from_provider'] = ['twitter', 'google_oauth2']
gitlab_rails['omniauth_sync_profile_attributes'] = ['name', 'email', 'location']
Self-compiled (source)
omniauth:
  sync_profile_from_provider: ['twitter', 'google_oauth2']
  sync_profile_attributes: ['email', 'location']

Bypass two-factor authentication

History
  • Introduced in GitLab 12.3.

With certain OmniAuth providers, users can sign in without using two-factor authentication (2FA).

Because of a known issue users must set up 2FA on their GitLab account to bypass 2FA. Otherwise, they are prompted to set up 2FA when they sign in to GitLab.

To bypass 2FA, you can either:

  • Define the allowed providers using an array (for example, ['twitter', 'google_oauth2']).
  • Specify true to allow all providers, or false to allow none.

This option should be configured only for providers that already have 2FA. The default is false.

This configuration doesn’t apply to SAML.

Linux package (Omnibus)
gitlab_rails['omniauth_allow_bypass_two_factor'] = ['twitter', 'google_oauth2']
Self-compiled (source)
omniauth:
  allow_bypass_two_factor: ['twitter', 'google_oauth2']

Sign in with a provider automatically

You can add the auto_sign_in_with_provider setting to your GitLab configuration to redirect login requests to your OmniAuth provider for authentication. This removes the need to select the provider before signing in.

For example, to enable automatic sign-in for the Azure v2 integration:

Linux package (Omnibus)
gitlab_rails['omniauth_auto_sign_in_with_provider'] = 'azure_activedirectory_v2'
Self-compiled (source)
omniauth:
  auto_sign_in_with_provider: azure_activedirectory_v2

Keep in mind that every sign-in attempt is redirected to the OmniAuth provider, so you can’t sign in using local credentials. Ensure at least one of the OmniAuth users is an administrator.

You can also bypass automatic sign-in by browsing to https://gitlab.example.com/users/sign_in?auto_sign_in=false.

Use a custom OmniAuth provider icon

Most supported providers include a built-in icon for the rendered sign-in button.

To use your own icon, ensure your image is optimized for rendering at 64 x 64 pixels, then override the icon in one of two ways:

  • Provide a custom image path:

    1. If you are hosting the image outside of your GitLab server domain, ensure your content security policies are configured to allow access to the image file.
    2. Depending on your method of installing GitLab, add a custom icon parameter to your GitLab configuration file. Read OpenID Connect OmniAuth provider for an example for the OpenID Connect provider.
  • Embed an image directly in a configuration file: This example creates a Base64-encoded version of your image you can serve through a Data URL:

    1. Encode your image file with a GNU base64 command (such as base64 -w 0 <logo.png>) which returns a single-line <base64-data> string.
    2. Add the Base64-encoded data to a custom icon parameter in your GitLab configuration file:

      omniauth:
        providers:
          - { name: '...'
              icon: 'data:image/png;base64,<base64-data>'
              ...
            }
      

Change apps or configuration

Because OAuth in GitLab doesn’t support setting the same external authentication and authorization provider as multiple providers, GitLab configuration and user identification must be updated at the same time if the provider or app is changed. For example, you can set up saml and azure_activedirectory_v2 but cannot add a second azure_activedirectory_v2 to the same configuration.

These instructions apply to all methods of authentication where GitLab stores an extern_uid and it is the only data used for user authentication.

When changing apps within a provider, if the user extern_uid does not change, only the GitLab configuration must be updated.

To swap configurations:

  1. Change provider configuration in your gitlab.rb file.
  2. Update extern_uid for all users that have an identity in GitLab for the previous provider.

To find the extern_uid, look at an existing user’s current extern_uid for an ID that matches the appropriate field in your current provider for the same user.

There are two methods to update the extern_uid:

  • Using the Users API. Pass the provider name and the new extern_uid.
  • Using the Rails console:

    Identity.where(extern_uid: 'old-id').update!(extern_uid: 'new-id')`
    

Known issues

Most supported OmniAuth providers don’t support Git over HTTP password authentication. As a workaround, you can authenticate using a personal access token.