• Configure SAML support in GitLab
  • Register GitLab in your SAML IdP
  • Configure SAML on your IdP
  • Configure GitLab to use multiple SAML IdPs
• Set up identity providers
  • Set up Okta
  • Set up Google Workspace
  • Set up other IdPs
  • Configure assertions
• Configure users based on SAML group membership
  • Prerequisites
  • Required groups
  • External groups
  • Administrator groups
  • Auditor groups
• Automatically manage SAML Group Sync
• Bypass two-factor authentication
  • Omnibus GitLab installations
  • Installations from source
• Validate response signatures
• Customize SAML settings
  • Redirect users to SAML server for authentication
  • Map SAML response attribute names
    • Set a username
  • Allow for clock drift
  • Designate a unique attribute for the uid
• Assertion encryption (optional)
• Sign SAML authentication requests (optional)
• Password generation for users created through SAML
• Link SAML identity for an existing user
• Configure group SAML SSO on a self-managed instance
• Additional configuration for SAML apps on your IdP
• Glossary of common terms
• Troubleshooting

SAML SSO for self-managed GitLab instances

This page describes how to set up instance-wide SAML single sign on (SSO) for self-managed GitLab instances.

You can configure GitLab to act as a SAML service provider (SP). This allows GitLab to consume assertions from a SAML identity provider (IdP), such as Okta, to authenticate users.

To set up SAML on GitLab.com, see SAML SSO for GitLab.com groups.

For more information on:

• OmniAuth provider settings, see the OmniAuth documentation.
• Commonly-used terms, see the glossary of common terms.

Configure SAML support in GitLab

1. Make sure GitLab is configured with HTTPS.

2. On your GitLab server, open the configuration file.

   For Omnibus installations:

   sudo editor /etc/gitlab/gitlab.rb
   

   For installations from source:

   cd /home/git/gitlab
   
   sudo -u git -H editor config/gitlab.yml
   

3. Edit the initial configuration settings.

4. To allow your users to use SAML to sign up without having to manually create an account first, add the following values to your configuration.

   For Omnibus installations:

   gitlab_rails['omniauth_allow_single_sign_on'] = ['saml']
   gitlab_rails['omniauth_block_auto_created_users'] = false
   

   For installations from source:

   omniauth:
     enabled: true
     allow_single_sign_on: ["saml"]
     block_auto_created_users: false
   

5. Optional. You can automatically link SAML users with existing GitLab users if their email addresses match by adding the following setting.

   For Omnibus installations:

   gitlab_rails['omniauth_auto_link_saml_user'] = true
   

   For installations from source:

   auto_link_saml_user: true
   

   Alternatively, a user can manually link their SAML identity to an existing GitLab account by enabling OmniAuth for an existing user.

6. Configure the following attributes so your SAML users cannot change them:

   • NameID.
   • Email when used with omniauth_auto_link_saml_user.

   If users can change these attributes, they can sign in as other authorized users. See your SAML IdP documentation for information on how to make these attributes unchangeable.

7. Add the provider configuration.

   For Omnibus installations:

   gitlab_rails['omniauth_providers'] = [
     {
       name: "saml",
       label: "Provider name", # optional label for login button, defaults to "Saml"
       args: {
         assertion_consumer_service_url: "https://gitlab.example.com/users/auth/saml/callback",
         idp_cert_fingerprint: "43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8",
         idp_sso_target_url: "https://login.example.com/idp",
         issuer: "https://gitlab.example.com",
         name_identifier_format: "urn:oasis:names:tc:SAML:2.0:nameid-format:persistent"
       }
     }
   ]
   

   For installations from source:

   omniauth:
     providers:
       - {
         name: 'saml',
         label: 'Provider name', # optional label for login button, defaults to "Saml"
         args: {
           assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
           idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
           idp_sso_target_url: 'https://login.example.com/idp',
           issuer: 'https://gitlab.example.com',
           name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent'
         }
       }
   

8. Match the value for assertion_consumer_service_url to the HTTPS endpoint of GitLab. To generate the correct value, append users/auth/saml/callback to the HTTPS URL of your GitLab installation.

9. Change the following values to match your IdP:
   • idp_cert_fingerprint.
   • idp_sso_target_url.
   • name_identifier_format. If you use a idp_cert_fingerprint, it must be a SHA1 fingerprint. For more information on these values, see the OmniAuth SAML documentation. For more information on other configuration settings, see configuring SAML on your IdP.

10. Change the value of issuer to a unique name, which identifies the application to the IdP.

11. For the changes to take effect, if you installed:
    • Using Omnibus, reconfigure GitLab.
    • From source, restart GitLab.

Register GitLab in your SAML IdP

1. Register the GitLab SP in your SAML IdP, using the application name specified in issuer.

2. To provide configuration information to the IdP, build a metadata URL for the application. To build the metadata URL for GitLab, append users/auth/saml/metadata to the HTTPS URL of your GitLab installation. For example:

   https://gitlab.example.com/users/auth/saml/metadata
   

   At a minimum the IdP must provide a claim containing the user’s email address using email or mail. For more information on other available claims, see configuring assertions.

3. On the sign in page there should now be a SAML icon below the regular sign in form. Select the icon to begin the authentication process. If authentication is successful, you are returned to GitLab and signed in.

Configure SAML on your IdP

To configure a SAML application on your IdP, you need at least the following information:

• Assertion consumer service URL.
• Issuer.
• NameID.
• Email address claim.

For an example configuration, see set up identity providers.

Your IdP may need additional configuration. For more information, see additional configuration for SAML apps on your IdP.

Configure GitLab to use multiple SAML IdPs

You can configure GitLab to use multiple SAML IdPs if:

• Each provider has a unique name set that matches a name set in args. At least one provider must have the name saml to mitigate a known issue in GitLab 14.6 and newer.
• The providers’ names are used:
  • In OmniAuth configuration for properties based on the provider name. For example, allowBypassTwoFactor, allowSingleSignOn, and syncProfileFromProvider.
  • For association to each existing user as an additional identity.
• The assertion_consumer_service_url matches the provider name.
• The strategy_class is explicitly set because it cannot be inferred from provider name.

SAML Group Sync does not support multiple IdPs. For more information, see issue 386605.

Example provider’s configuration for installations from source:

omniauth:
  providers:
    - {
      name: 'saml', # This must match the following name configuration parameter
      args: {
        name: 'saml', # This is mandatory and must match the provider name
        strategy_class: 'OmniAuth::Strategies::SAML',
        assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml_1/callback', # URL must match the name of the provider
        ... # Put here all the required arguments similar to a single provider
      },
      label: 'Provider 1' # Differentiate the two buttons and providers in the UI
    }
    - {
      name: 'saml1', # This must match the following name configuration parameter
      args: {
        name: 'saml1', # This is mandatory and must match the provider name
        strategy_class: 'OmniAuth::Strategies::SAML',
        assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml_2/callback', # URL must match the name of the provider
        ... # Put here all the required arguments similar to a single provider
      },
      label: 'Provider 2' # Differentiate the two buttons and providers in the UI
    }

Example provider’s configuration for Omnibus GitLab installations:

To allow your users to use SAML to sign up without having to manually create an account from either of the providers, add the following values to your configuration.

gitlab_rails['omniauth_allow_single_sign_on'] = ['saml', 'saml1']

gitlab_rails['omniauth_providers'] = [
  {
    name: 'saml', # This must match the following name configuration parameter
    args: {
            name: 'saml', # This is mandatory and must match the provider name
            strategy_class: 'OmniAuth::Strategies::SAML',
            assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml_1/callback', # URL must match the name of the provider
            ... # Put here all the required arguments similar to a single provider
          },
    label: 'Provider 1' # Differentiate the two buttons and providers in the UI
  },
  {
    name: 'saml1', # This must match the following name configuration parameter
    args: {
            name: 'saml1', # This is mandatory and must match the provider name
            strategy_class: 'OmniAuth::Strategies::SAML',
            assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml_2/callback', # URL must match the name of the provider
            ... # Put here all the required arguments similar to a single provider
          },
    label: 'Provider 2' # Differentiate the two buttons and providers in the UI
  }
]

To allow your users to use SAML to sign up without having to manually create an account from either of the providers, add the following values to your configuration.

gitlab_rails['omniauth_allow_single_sign_on'] = ['saml', 'saml1']

Set up identity providers

GitLab support of SAML means you can sign in to GitLab through a wide range of IdPs.

GitLab provides the following content on setting up the Okta and Google Workspace IdPs for guidance only. If you have any questions on configuring either of these IdPs, contact your provider’s support.

Set up Okta

1. In the Okta administrator section choose Applications.
2. On the app screen, select Create App Integration and then select SAML 2.0 on the next screen.
3. Optional. Choose and add a logo from GitLab Press. You must crop and resize the logo.
4. Complete the SAML general configuration. Enter:
   • "Single sign-on URL": Use the assertion consumer service URL.
   • "Audience URI": Use the issuer.
   • NameID.
   • Assertions.
5. In the feedback section, enter that you’re a customer and creating an app for internal use.
6. At the top of your new app’s profile, select SAML 2.0 configuration instructions.
7. Note the Identity Provider Single Sign-On URL. Use this URL for the idp_sso_target_url on your GitLab configuration file.
8. Before you sign out of Okta, make sure you add your user and groups if any.

Set up Google Workspace

Prerequisites:

• Make sure you have access to a Google Workspace Super Admin account.

1. Use the following information, and follow the instructions in Set up your own custom SAML application in Google Workspace.

   	Typical value	Description
   Name of SAML App	GitLab	Other names OK.
   ACS URL	https://<GITLAB_DOMAIN>/users/auth/saml/callback	Assertion Consumer Service URL.
   GITLAB_DOMAIN	gitlab.example.com	Your GitLab instance domain.
   Entity ID	https://gitlab.example.com	A value unique to your SAML application. Set it to the issuer in your GitLab configuration.
   Name ID format	EMAIL	Required value. Also known as name_identifier_format.
   Name ID	Primary email address	Your email address. Make sure someone receives content sent to that address.
   First name	first_name	First name. Required value to communicate with GitLab.
   Last name	last_name	Last name. Required value to communicate with GitLab.

2. Set up the following SAML attribute mappings:

   Google Directory attributes	App attributes
   Basic information > Email	email
   Basic Information > First name	first_name
   Basic Information > Last name	last_name

   You might use some of this information when you configure SAML support in GitLab.

When configuring the Google Workspace SAML application, record the following information:

Google Workspace Administrator also provides the IdP metadata, Entity ID, and SHA-256 fingerprint. However, GitLab does not need this information to connect to the Google Workspace SAML application.

Set up other IdPs

Some IdPs have documentation on how to use them as the IdP in SAML configurations. For example:

• Active Directory Federation Services (ADFS)
• Auth0

If you have any questions on configuring your IdP in a SAML configuration, contact your provider’s support.

Configure assertions

See attribute_statements for:

• Custom assertion configuration examples.
• How to configure custom username attributes.

For a full list of supported assertions, see the OmniAuth SAML gem

Configure users based on SAML group membership

You can:

• Require users to be members of a certain group.
• Assign users external, administrator or auditor roles based on group membership.

GitLab checks these groups on each SAML sign in and updates user attributes as necessary. This feature does not allow you to automatically add users to GitLab Groups.

Support for these groups depends on:

• Your subscription.
• Whether you’ve installed GitLab Enterprise Edition (EE).

Prerequisites

You must tell GitLab where to look for group information. To do this, make sure that your IdP server sends a specific AttributeStatement along with the regular SAML response. For example:

<saml:AttributeStatement>
  <saml:Attribute Name="Groups">
    <saml:AttributeValue xsi:type="xs:string">Developers</saml:AttributeValue>
    <saml:AttributeValue xsi:type="xs:string">Freelancers</saml:AttributeValue>
    <saml:AttributeValue xsi:type="xs:string">Admins</saml:AttributeValue>
    <saml:AttributeValue xsi:type="xs:string">Auditors</saml:AttributeValue>
  </saml:Attribute>
</saml:AttributeStatement>

The name of the attribute must contain the groups that a user belongs to. To tell GitLab where to find these groups, add a groups_attribute: element to your SAML settings.

Required groups

Your IdP passes group information to GitLab in the SAML response. To use this response, configure GitLab to identify:

• Where to look for the groups in the SAML response, using the groups_attribute setting.
• Information about a group or user, using a group setting.

Use the required_groups setting to configure GitLab to identify which group membership is required to sign in.

If you do not set required_groups or leave the setting empty, anyone with proper authentication can use the service.

Example configuration:

{ name: 'saml',
  label: 'Our SAML Provider',
  groups_attribute: 'Groups',
  required_groups: ['Developers', 'Freelancers', 'Admins', 'Auditors'],
  args: {
          assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
          idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
          idp_sso_target_url: 'https://login.example.com/idp',
          issuer: 'https://gitlab.example.com',
          name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent'
  } }

External groups

Your IdP passes group information to GitLab in the SAML response. To use this response, configure GitLab to identify:

• Where to look for the groups in the SAML response, using the groups_attribute setting.
• Information about a group or user, using a group setting.

SAML can automatically identify a user as an external user, based on the external_groups setting.

Example configuration:

{ name: 'saml',
  label: 'Our SAML Provider',
  groups_attribute: 'Groups',
  external_groups: ['Freelancers'],
  args: {
          assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
          idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
          idp_sso_target_url: 'https://login.example.com/idp',
          issuer: 'https://gitlab.example.com',
          name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent'
  } }

Administrator groups

Your IdP passes group information to GitLab in the SAML response. To use this response, configure GitLab to identify:

• Where to look for the groups in the SAML response, using the groups_attribute setting.
• Information about a group or user, using a group setting.

Use the admin_groups setting to configure GitLab to identify which groups grant the user administrator access.

Example configuration:

{ name: 'saml',
  label: 'Our SAML Provider',
  groups_attribute: 'Groups',
  admin_groups: ['Admins'],
  args: {
          assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
          idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
          idp_sso_target_url: 'https://login.example.com/idp',
          issuer: 'https://gitlab.example.com',
          name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent'
  } }

Auditor groups

Your IdP passes group information to GitLab in the SAML response. To use this response, configure GitLab to identify:

• Where to look for the groups in the SAML response, using the groups_attribute setting.
• Information about a group or user, using a group setting.

Use the auditor_groups setting to configure GitLab to identify which groups include users with auditor access.

Example configuration:

{ name: 'saml',
  label: 'Our SAML Provider',
  groups_attribute: 'Groups',
  auditor_groups: ['Auditors'],
  args: {
          assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
          idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
          idp_sso_target_url: 'https://login.example.com/idp',
          issuer: 'https://gitlab.example.com',
          name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent'
  } }

Automatically manage SAML Group Sync

For information on automatically managing GitLab group membership, see SAML Group Sync.

Bypass two-factor authentication

To configure a SAML authentication method to count as two-factor authentication (2FA) on a per session basis, register that method in the upstream_two_factor_authn_contexts list.

1. Make sure that your IdP is returning the AuthnContext. For example:

<saml:AuthnStatement>
    <saml:AuthnContext>
        <saml:AuthnContextClassRef>urn:oasis:names:tc:SAML:2.0:ac:classes:MediumStrongCertificateProtectedTransport</saml:AuthnContextClassRef>
    </saml:AuthnContext>
</saml:AuthnStatement>

1. Edit your installation configuration to register the SAML authentication method in the upstream_two_factor_authn_contexts list. How you edit your configuration will differ depending on your installation type.

Omnibus GitLab installations

1. Edit /etc/gitlab/gitlab.rb:

   gitlab_rails['omniauth_providers'] = [
     {
       name: "saml",
       args: {
         assertion_consumer_service_url: "https://gitlab.example.com/users/auth/saml/callback",
         idp_cert_fingerprint: "43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8",
         idp_sso_target_url: "https://login.example.com/idp",
         issuer: "https://gitlab.example.com",
         name_identifier_format: "urn:oasis:names:tc:SAML:2.0:nameid-format:persistent",
         upstream_two_factor_authn_contexts:
           %w(
             urn:oasis:names:tc:SAML:2.0:ac:classes:CertificateProtectedTransport
             urn:oasis:names:tc:SAML:2.0:ac:classes:SecondFactorOTPSMS
             urn:oasis:names:tc:SAML:2.0:ac:classes:SecondFactorIGTOKEN
           )
       },
       label: "Company Login" # optional label for SAML login button, defaults to "Saml"
     }
   ]
   

2. Save the file and reconfigure GitLab for the changes to take effect.

Installations from source

1. Edit config/gitlab.yml:

   omniauth:
     providers:
       - {
         name: 'saml',
         args: {
           assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
           idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
           idp_sso_target_url: 'https://login.example.com/idp',
           issuer: 'https://gitlab.example.com',
           name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
           upstream_two_factor_authn_contexts:
             [
               'urn:oasis:names:tc:SAML:2.0:ac:classes:CertificateProtectedTransport',
               'urn:oasis:names:tc:SAML:2.0:ac:classes:SecondFactorOTPSMS',
               'urn:oasis:names:tc:SAML:2.0:ac:classes:SecondFactorIGTOKEN'
             ]
         },
         label: 'Company Login'  # optional label for SAML login button, defaults to "Saml"
       }
   

2. Save the file and restart GitLab for the changes to take effect.

Validate response signatures

IdPs must sign SAML responses to ensure that the assertions are not tampered with.

This prevents user impersonation and privilege escalation when specific group membership is required.

You configure the response signature validation using idp_cert_fingerprint. An example configuration:

args: {
  assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
  idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
  idp_sso_target_url: 'https://login.example.com/idp',
  issuer: 'https://gitlab.example.com',
  name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
}

If your IdP does not support configuring this using idp_cert_fingerprint, you can instead configure GitLab directly using idp_cert. An example configuration:

args: {
  assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
  idp_cert: '-----BEGIN CERTIFICATE-----
    <redacted>
    -----END CERTIFICATE-----',
  idp_sso_target_url: 'https://login.example.com/idp',
  issuer: 'https://gitlab.example.com',
  name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
}

If you have configured the response signature validation incorrectly, you might see error messages such as:

• A key validation error.
• Digest mismatch.
• Fingerprint mismatch.

For more information on solving these errors, see the troubleshooting SAML guide.

Customize SAML settings

Redirect users to SAML server for authentication

You can add the auto_sign_in_with_provider setting to your GitLab configuration to automatically redirect you to your SAML server for authentication. This removes the requirement to select an element before actually signing in.

For Omnibus GitLab installations:

gitlab_rails['omniauth_auto_sign_in_with_provider'] = 'saml'

For installations from source:

omniauth:
  auto_sign_in_with_provider: saml

Every sign in attempt redirects to the SAML server, so you cannot sign in using local credentials. Make sure at least one of the SAML users has administrator access.

You can also bypass the auto sign-in feature by https://gitlab.example.com/users/sign_in?auto_sign_in=false.

Map SAML response attribute names

You can use attribute_statements to map attribute names in a SAML response to entries in the OmniAuth info hash.

For example, if your SAMLResponse contains an Attribute called EmailAddress, specify { email: ['EmailAddress'] } to map the Attribute to the corresponding key in the info hash. URI-named Attributes are also supported, for example, { email: ['http://schemas.xmlsoap.org/ws/2005/05/identity/claims/emailaddress'] }.

Use this setting to tell GitLab where to look for certain attributes required to create an account. If your IdP sends the user’s email address as EmailAddress instead of email, let GitLab know by setting it on your configuration:

args: {
        assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
        idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
        idp_sso_target_url: 'https://login.example.com/idp',
        issuer: 'https://gitlab.example.com',
        name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
        attribute_statements: { email: ['EmailAddress'] }
}

Set a username

By default, the local part of the email address in the SAML response is used to generate the user’s GitLab username.

Configure nickname in attribute_statements to specify one or more attributes that contain a user’s desired username:

args: {
        assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
        idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
        idp_sso_target_url: 'https://login.example.com/idp',
        issuer: 'https://gitlab.example.com',
        name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
        attribute_statements: { nickname: ['username'] }
}

This also sets the username attribute in your SAML Response to the username in GitLab.

Allow for clock drift

The clock of the IdP may drift slightly ahead of your system clocks. To allow for a small amount of clock drift, use allowed_clock_drift in your settings. You must enter the parameter’s value in a number and fraction of seconds. The value given is added to the current time at which the response is validated.

args: {
        assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
        idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
        idp_sso_target_url: 'https://login.example.com/idp',
        issuer: 'https://gitlab.example.com',
        name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
        attribute_statements: { email: ['EmailAddress'] },
        allowed_clock_drift: 1  # for one second clock drift
}

Designate a unique attribute for the uid

By default, the uid is set as the name_id in the SAML response. To designate a unique attribute for the uid, you can set the uid_attribute. In the following example, the value of uid attribute in the SAML response is set as the uid_attribute.

args: {
        assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
        idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
        idp_sso_target_url: 'https://login.example.com/idp',
        issuer: 'https://gitlab.example.com',
        name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
        uid_attribute: 'uid'
}

Before setting the uid to a unique attribute, make sure that you have configured the following attributes so your SAML users cannot change them:

• NameID.
• Email when used with omniauth_auto_link_saml_user.

If users can change these attributes, they can sign in as other authorized users. See your SAML IdP documentation for information on how to make these attributes unchangeable.

Assertion encryption (optional)

GitLab requires the use of TLS encryption with SAML 2.0. Sometimes, GitLab needs additional assertion encryption. For example, if you:

• Terminate TLS encryption early at a load balancer.
• Include sensitive details in assertions that you do not want appearing in logs.

Most organizations should not need additional encryption at this layer.

The SAML integration supports EncryptedAssertion. To encrypt your assertions, define the private key and the public certificate of your GitLab instance in the SAML settings.

When you define the key and certificate, replace all line feeds in the key file with \n. This makes the key file one long string with no line feeds.

args: {
  assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
  idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
  idp_sso_target_url: 'https://login.example.com/idp',
  issuer: 'https://gitlab.example.com',
  name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
  certificate: '-----BEGIN CERTIFICATE-----\n<redacted>\n-----END CERTIFICATE-----',
  private_key: '-----BEGIN PRIVATE KEY-----\n<redacted>\n-----END PRIVATE KEY-----'
}

Your IdP encrypts the assertion with the public certificate of GitLab. GitLab decrypts the EncryptedAssertion with its private key.

Sign SAML authentication requests (optional)

You can configure GitLab to sign SAML authentication requests. This configuration is optional because GitLab SAML requests use the SAML redirect binding.

To implement signing:

1. Create a private key and public certificate pair for your GitLab instance to use for SAML.
2. Configure the signing settings in the security section of the configuration. For example:

args: {
  assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback',
  idp_cert_fingerprint: '43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8',
  idp_sso_target_url: 'https://login.example.com/idp',
  issuer: 'https://gitlab.example.com',
  name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
  certificate: '-----BEGIN CERTIFICATE-----\n<redacted>\n-----END CERTIFICATE-----',
  private_key: '-----BEGIN PRIVATE KEY-----\n<redacted>\n-----END PRIVATE KEY-----',
  security: {
    authn_requests_signed: true,  # enable signature on AuthNRequest
    want_assertions_signed: true,  # enable the requirement of signed assertion
    metadata_signed: false,  # enable signature on Metadata
    signature_method: 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha256',
    digest_method: 'http://www.w3.org/2001/04/xmlenc#sha256',
  }
}

GitLab then:

• Signs the request with the provided private key.
• Includes the configured public x500 certificate in the metadata for your IdP to validate the signature of the received request with.

For more information on this option, see the Ruby SAML gem documentation.

The Ruby SAML gem is used by the OmniAuth SAML gem to implement the client side of the SAML authentication.

Password generation for users created through SAML

GitLab generates and sets passwords for users created through SAML.

Users authenticated with SSO or SAML must not use a password for Git operations over HTTPS. These users can instead:

• Set up a personal access token.
• Use the Git Credential Manager which securely authenticates using OAuth.

Link SAML identity for an existing user

A user can manually link their SAML identity to an existing GitLab account by following the steps in Enable OmniAuth for an existing user.

Configure group SAML SSO on a self-managed instance

Use group SAML SSO if you have to allow access through multiple SAML IdPs on your self-managed instance.

To configure group SAML SSO:

1. Configure GitLab with HTTPS.

2. Enable OmniAuth and the group_saml provider.

   To do this for Omnibus GitLab installations, edit gitlab.rb:

   gitlab_rails['omniauth_enabled'] = true
   gitlab_rails['omniauth_providers'] = [{ name: 'group_saml' }]
   

   For installations from source, edit gitlab/config/gitlab.yml:

    omniauth:
      enabled: true
      providers:
        - { name: 'group_saml' }
   

As a multi-tenant solution, group SAML on a self-managed instance is limited compared to the recommended instance-wide SAML. Use instance-wide SAML to take advantage of:

• LDAP compatibility.
• LDAP Group Sync.
• Required groups.
• Administrator groups.
• Auditor groups.

Additional configuration for SAML apps on your IdP

When configuring a SAML app on the IdP, your IdP may need additional configuration, such as the following:

For example configurations, see the notes on specific providers.

Glossary of common terms

Troubleshooting

See our troubleshooting SAML guide.