gitlab-org--gitlab-foss/doc/integration/omniauth.md

# OmniAuth

GitLab leverages OmniAuth to allow users to sign in using Twitter, GitHub, and
other popular services. [OmniAuth](https://rubygems.org/gems/omniauth/) is
"a generalized Rack framework for multiple-provider authentication, built on Ruby.

Configuring OmniAuth does not prevent standard GitLab authentication or LDAP
(if configured) from continuing to work. Users can choose to sign in using any
of the configured mechanisms.

- [Initial OmniAuth Configuration](#initial-omniauth-configuration)
- [Supported Providers](#supported-providers)
- [Enable OmniAuth for an Existing User](#enable-omniauth-for-an-existing-user)
- [OmniAuth configuration sample when using Omnibus GitLab](https://gitlab.com/gitlab-org/omnibus-gitlab/tree/master#omniauth-google-twitter-github-login)
- [Enable or disable Sign In with an OmniAuth provider without disabling import sources](#enable-or-disable-sign-in-with-an-omniauth-provider-without-disabling-import-sources)

## Supported Providers

This is a list of the current supported OmniAuth providers. Before proceeding
on each provider's documentation, make sure to first read this document as it
contains some settings that are common for all providers.

- [GitHub](github.md)
- [Bitbucket](bitbucket.md)
- [GitLab.com](gitlab.md)
- [Google](google.md)
- [Facebook](facebook.md)
- [Twitter](twitter.md)
- [Shibboleth](shibboleth.md)
- [SAML](saml.md)
- [Crowd](../administration/auth/crowd.md)
- [Azure](azure.md)
- [Auth0](auth0.md)
- [Authentiq](../administration/auth/authentiq.md)
- [OAuth2Generic](oauth2_generic.md)
- [JWT](../administration/auth/jwt.md)
- [OpenID Connect](../administration/auth/oidc.md)
- [Salesforce](salesforce.md)
- [AWS Cognito](../administration/auth/cognito.md)

## Initial OmniAuth Configuration

Before configuring individual OmniAuth providers there are a few global settings
that are in common for all providers that we need to consider.

NOTE: **Note:**
Starting from GitLab 11.4, OmniAuth is enabled by default. If you're using an
earlier version, you'll need to explicitly enable it.

- `allow_single_sign_on` allows you to specify the providers you want to allow to
  automatically create an account. It defaults to `false`. If `false` users must
  be created manually or they will not be able to sign in via OmniAuth.
- `auto_link_ldap_user` can be used if you have [LDAP / ActiveDirectory](../administration/auth/ldap/index.md)
  integration enabled. It defaults to `false`. When enabled, users automatically
  created through an OmniAuth provider will have their LDAP identity created in GitLab as well.
- `block_auto_created_users` defaults to `true`. If `true` auto created users will
  be blocked by default and will have to be unblocked by an administrator before
  they are able to sign in.

NOTE: **Note:**
If you set `block_auto_created_users` to `false`, make sure to only
define providers under `allow_single_sign_on` that you are able to control, like
SAML, Shibboleth, Crowd or Google, or set it to `false` otherwise any user on
the Internet will be able to successfully sign in to your GitLab without
administrative approval.

NOTE: **Note:**
`auto_link_ldap_user` requires the `uid` of the user to be the same in both LDAP
and the OmniAuth provider.

To change these settings:

- **For Omnibus package**

  Open the configuration file:

  ```shell
  sudo editor /etc/gitlab/gitlab.rb
  ```

  and change:

  ```ruby
  # CAUTION!
  # This allows users to login without having a user account first. Define the allowed providers
  # using an array, e.g. ["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
  ```

- **For installations from source**

  Open the configuration file:

  ```shell
  cd /home/git/gitlab

  sudo -u git -H editor config/gitlab.yml
  ```

  and change the following section:

  ```yaml
  ## OmniAuth settings
  omniauth:
    # Allow login via 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 login without having a user account first. Define the allowed providers
    # using an array, e.g. ["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
  ```

Now we can choose one or more of the [Supported Providers](#supported-providers)
listed above to continue the configuration process.

## Enable OmniAuth for an Existing User

Existing users can enable OmniAuth for specific providers after the account is
created. For example, if the user originally signed in with LDAP, an OmniAuth
provider such as Twitter can be enabled. Follow the steps below to enable an
OmniAuth provider for an existing user.

1. Sign in normally - whether standard sign in, LDAP, or another OmniAuth provider.
1. Go to profile settings (the silhouette icon in the top right corner).
1. Select the "Account" tab.
1. Under "Connected Accounts" select the desired OmniAuth provider, such as Twitter.
1. The user will be redirected to the provider. Once the user authorized GitLab
   they will be redirected back to GitLab.

The chosen OmniAuth provider is now active and can be used to sign in to GitLab from then on.

## Automatically Link Existing Users to OmniAuth Users

> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/36664) in GitLab 13.4.

You can automatically link OmniAuth users with existing GitLab users if their email addresses match.
For example, the following setting is used to enable the auto link feature for both a SAML provider and the Twitter OAuth provider:

**For Omnibus installations**

```ruby
gitlab_rails['omniauth_auto_link_user'] = ["saml", "twitter"]
```

**For installations from source**

```yaml
omniauth:
  auto_link_user: ["saml", "twitter"]
```

## Configure OmniAuth Providers as External

> Introduced in GitLab 8.7.

You can define which OmniAuth providers you want to be `external` so that all users
**creating accounts, or logging in via these providers** will not be able to have
access to internal projects. You will need to use the full name of the provider,
like `google_oauth2` for Google. Refer to the examples for the full names of the
supported providers.

NOTE: **Note:**
If you decide to remove an OmniAuth provider from the external providers list
you will need to manually update the users that use this method to login, if you
want their accounts to be upgraded to full internal accounts.

**For Omnibus installations**

```ruby
gitlab_rails['omniauth_external_providers'] = ['twitter', 'google_oauth2']
```

**For installations from source**

```yaml
omniauth:
  external_providers: ['twitter', 'google_oauth2']
```

## Using Custom OmniAuth Providers

NOTE: **Note:**
The following information only applies for installations from source.

GitLab uses [OmniAuth](https://github.com/omniauth/omniauth) for authentication and already ships
with a few providers pre-installed (e.g. LDAP, GitHub, Twitter). But sometimes that
is not enough and you need to integrate with other authentication solutions. For
these cases you can use the OmniAuth provider.

### Steps

These steps are fairly general and you will need to figure out the exact details
from the OmniAuth provider's documentation.

- Stop GitLab:

  ```shell
  sudo service gitlab stop
  ```

- Add the gem to your [Gemfile](https://gitlab.com/gitlab-org/gitlab/blob/master/Gemfile):

  ```shell
  gem "omniauth-your-auth-provider"
  ```

- Install the new OmniAuth provider gem by running the following command:

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

  > These are the same commands you used during initial installation in the [Install Gems section](../install/installation.md#install-gems) with `--path vendor/bundle --no-deployment` instead of `--deployment`.

- Start GitLab:

  ```shell
  sudo service gitlab start
  ```

### Examples

If you have successfully set up a provider that is not shipped with GitLab itself,
please let us know.

You can help others by reporting successful configurations and probably share a
few insights or provide warnings for common errors or pitfalls by sharing your
experience [in the public Wiki](https://github.com/gitlabhq/gitlab-public-wiki/wiki/Custom-omniauth-provider-configurations).

While we can't officially support every possible authentication mechanism out there,
we'd like to at least help those with specific needs.

## Enable or disable Sign In with an OmniAuth provider without disabling import sources

> Introduced in GitLab 8.8.

Administrators are able to enable or disable Sign In via some OmniAuth providers.

NOTE: **Note:**
By default Sign In is enabled via all the OAuth Providers that have been configured in `config/gitlab.yml`.

In order to enable/disable an OmniAuth provider, go to Admin Area -> Settings -> Sign-in Restrictions section -> Enabled OAuth Sign-In sources and select the providers you want to enable or disable.

![Enabled OAuth Sign-In sources](img/enabled-oauth-sign-in-sources.png)

## Disabling OmniAuth

Starting from version 11.4 of GitLab, OmniAuth is enabled by default. This only
has an effect if providers are configured and [enabled](#enable-or-disable-sign-in-with-an-omniauth-provider-without-disabling-import-sources).

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

**For Omnibus installations**

```ruby
gitlab_rails['omniauth_enabled'] = false
```

**For installations from source**

```yaml
omniauth:
  enabled: false
```

## Keep OmniAuth user profiles up to date

You can enable profile syncing from selected OmniAuth providers and for all or for specific user information.

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

```ruby
gitlab_rails['omniauth_sync_profile_from_provider'] = ['twitter', 'google_oauth2']
gitlab_rails['omniauth_sync_profile_attributes'] = ['name', 'email', 'location']
```

**For installations from source**

```yaml
omniauth:
  sync_profile_from_provider: ['twitter', 'google_oauth2']
  sync_profile_attributes: ['email', 'location']
```

## Bypassing two factor authentication

Starting with GitLab 12.3, this allows users to login with the specified
providers without two factor authentication.

Define the allowed providers using an array, e.g. `["twitter", 'google_oauth2']`, or as
`true`/`false` to allow all providers or none. This option should only be configured
for providers which already have two factor authentication (default: false).
This configuration dose not apply to SAML.

```ruby
gitlab_rails['omniauth_allow_bypass_two_factor'] = ['twitter', 'google_oauth2']
```

**For installations from source**

```yaml
omniauth:
  allow_bypass_two_factor: ['twitter', 'google_oauth2']
```

## Automatically sign in with provider

You can add the `auto_sign_in_with_provider` setting to your
GitLab configuration to automatically redirect login requests
to your OmniAuth provider for authentication, thus removing the need to click a button
before actually signing in.

For example, when using the Azure integration, you would set the following
to enable auto sign in.

For Omnibus package:

```ruby
gitlab_rails['omniauth_auto_sign_in_with_provider'] = 'azure_oauth2'
```

For installations from source:

```yaml
omniauth:
  auto_sign_in_with_provider: azure_oauth2
```

Please keep in mind that every sign in attempt will be redirected to the OmniAuth provider,
so you will not be able to sign in using local credentials. Make sure that at least one
of the OmniAuth users has admin permissions.

You may also bypass the auto signin feature by browsing to
`https://gitlab.example.com/users/sign_in?auto_sign_in=false`.

## Passwords for users created via OmniAuth

The [Generated passwords for users created through integrated authentication](../security/passwords_for_integrated_authentication_methods.md) guide provides an overview of how GitLab generates and sets passwords for users created via OmniAuth.