SCIM provisioning using SAML SSO for GitLab.com groups

Introduced in GitLab 11.10.

System for Cross-domain Identity Management (SCIM), is an open standard that enables the automation of user provisioning. When SCIM is provisioned for a GitLab group, membership of that group is synchronized between GitLab and the identity provider.

The GitLab SCIM API implements part of the RFC7644 protocol.

Features

The following actions are available:

  • Create users
  • Remove users (deactivate SCIM identity)

The following identity providers are supported:

  • Azure
  • Okta

Requirements

GitLab configuration

Once Group Single Sign-On has been configured, we can:

  1. On the top bar, select Menu > Groups and find your group.
  2. On the left sidebar, select Settings > SAML SSO.
  3. Select Generate a SCIM token.
  4. Save the token and URL for use in the next step.

SCIM token configuration

Identity Provider configuration

Azure configuration steps

The SAML application that was created during Single sign-on setup for Azure now needs to be set up for SCIM. You can refer to Azure SCIM setup documentation.

  1. In your app, go to the Provisioning tab, and set the Provisioning Mode to Automatic. Then fill in the Admin Credentials, and save. The Tenant URL and secret token are the items retrieved in the previous step.

  2. After saving, two more tabs appear:

    • Settings: We recommend setting a notification email and selecting the Send an email notification when a failure occurs checkbox. You also control what is actually synced by selecting the Scope. For example, Sync only assigned users and groups only syncs the users and groups assigned to the application. Otherwise, it syncs the whole Active Directory.

    • Mappings: We recommend keeping Provision Azure Active Directory Users enabled, and disable Provision Azure Active Directory Groups. Leaving Provision Azure Active Directory Groups enabled does not break the SCIM user provisioning, but it causes errors in Azure AD that may be confusing and misleading.

  3. You can then test the connection by selecting Test Connection. If the connection is successful, save your configuration before moving on. See below for troubleshooting.

Configure attribute mapping

Follow Azure documentation to configure the attribute mapping.

The following table below provides an attribute mapping known to work with GitLab. If your SAML configuration differs from the recommended SAML settings, modify the corresponding customappsso settings accordingly. If a mapping is not listed in the table, use the Azure defaults. For a list of required attributes, refer to the SCIM API documentation.

Azure Active Directory Attribute customappsso Attribute Matching precedence
objectId externalId 1
userPrincipalName emails[type eq "work"].value  
mailNickname userName  

For guidance, you can view an example configuration in the troubleshooting reference.

  1. Below the mapping list select Show advanced options > Edit attribute list for AppName.

  2. Ensure the id is the primary and required field, and externalId is also required.

    note
    username should neither be primary nor required as we don’t support that field on GitLab SCIM yet.
  3. Save all changes.
  4. In the Provisioning step, set the Provisioning Status to On.

Once enabled, the synchronization details and any errors appears on the bottom of the Provisioning screen, together with a link to the audit events.

caution
Once synchronized, changing the field mapped to id and externalId may cause a number of errors. These include provisioning errors, duplicate users, and may prevent existing users from accessing the GitLab group.

Okta configuration steps

Before you start this section:

  • Check that you are using Okta Lifecycle Management product. This product tier is required to use SCIM on Okta. To check which Okta product you are using, check your signed Okta contract, contact your Okta AE, CSM, or Okta support.
  • Complete the GitLab configuration process.
  • Complete the setup for SAML application for Okta, as described in the Okta setup notes.
  • Check that your Okta SAML setup matches our documentation exactly, especially the NameID configuration. Otherwise, the Okta SCIM app may not work properly.

After the above steps are complete:

  1. Sign in to Okta.
  2. Ensure you are in the Admin Area by selecting the Admin button located in the top right. The button is not visible from the Admin Area.
  3. In the Application tab, select Browse App Catalog.
  4. Search for GitLab, find and select the ‘GitLab’ application.
  5. On the GitLab application overview page, select Add.
  6. Under Application Visibility select both checkboxes. Currently the GitLab application does not support SAML authentication so the icon should not be shown to users.
  7. Select Done to finish adding the application.
  8. In the Provisioning tab, select Configure API integration.
  9. Select Enable API integration.
    • For Base URL enter the URL obtained from the GitLab SCIM configuration page
    • For API Token enter the SCIM token obtained from the GitLab SCIM configuration page
  10. Select ‘Test API Credentials’ to verify configuration.
  11. Select Save to apply the settings.
  12. After saving the API integration details, new settings tabs appear on the left. Select To App.
  13. Select Edit.
  14. Select the Enable checkbox for both Create Users and Deactivate Users.
  15. Select Save.
  16. Assign users in the Assignments tab. Assigned users are created and managed in your GitLab group.

Okta Known Issues

The Okta GitLab application currently only supports SCIM. Continue using the separate Okta SAML SSO configuration along with the new SCIM application described above. An issue exists to add SAML support to the Okta GitLab application.

OneLogin

As the developers of this app, OneLogin provides a “GitLab (SaaS)” app in their catalog, which includes a SCIM integration. Please reach out to OneLogin if you encounter issues.

User access and linking setup

During the synchronization process, all of your users get GitLab accounts, welcoming them to their respective groups, with an invitation email. When implementing SCIM provisioning, you may want to warn your security-conscious employees about this email.

The following diagram is a general outline on what happens when you add users to your SCIM app:

graph TD A[Add User to SCIM app] -->|IdP sends user info to GitLab| B(GitLab: Does the email exist?) B -->|No| C[GitLab creates user with SCIM identity] B -->|Yes| D[GitLab sends message back 'Email exists']

During provisioning:

  • Both primary and secondary emails are considered when checking whether a GitLab user account exists.
  • Duplicate usernames are also handled, by adding suffix 1 upon user creation. For example, due to already existing test_user username, test_user1 is used.

If Group SAML has been configured and you have an existing GitLab.com account, you can link your SCIM and SAML identities:

  1. Update the primary email address in your GitLab.com user account to match the user profile email address in your identity provider.
  2. Link your SAML identity.

We recommend users do this prior to turning on sync, because while synchronization is active, there may be provisioning errors for existing users.

New users and existing users on subsequent visits can access the group through the identify provider’s dashboard or by visiting links directly.

In GitLab 14.0 and later, GitLab users created by SAML SSO or SCIM provisioning display with an Enterprise badge in the Members view.

Enterprise badge for users created with a SCIM identity

For role information, please see the Group SAML page

Blocking access

To rescind access to the top-level group, all sub-groups, and projects, remove or deactivate the user on the identity provider. After the identity provider performs a sync, based on its configured schedule, the user’s membership is revoked and they lose access.

note
Deprovisioning does not delete the GitLab user account.
graph TD A[Remove User from SCIM app] -->|IdP sends request to GitLab| B(GitLab: Is the user part of the group?) B -->|No| C[Nothing to do] B -->|Yes| D[GitLab removes user from GitLab group]

Troubleshooting

This section contains possible solutions for problems you might encounter.

How come I can’t add a user after I removed them?

As outlined in the Blocking access section, when you remove a user, they are removed from the group. However, their account is not deleted.

When the user is added back to the SCIM app, GitLab cannot create a new user because the user already exists.

Solution: Have a user sign in directly to GitLab, then manually link their account.

How do I diagnose why a user is unable to sign in

Ensure that the user has been added to the SCIM app.

If you receive “User is not linked to a SAML account”, then most likely the user already exists in GitLab. Have the user follow the User access and linking setup instructions.

The Identity (extern_uid) value stored by GitLab is updated by SCIM whenever id or externalId changes. Users cannot sign in unless the GitLab Identity (extern_uid) value matches the NameId sent by SAML.

This value is also used by SCIM to match users on the id, and is updated by SCIM whenever the id or externalId values change.

It is important that this SCIM id and SCIM externalId are configured to the same value as the SAML NameId. SAML responses can be traced using debugging tools, and any errors can be checked against our SAML troubleshooting docs.

How do I verify user’s SAML NameId matches the SCIM externalId

Group owners can see the list of users and the externalId stored for each user in the group SAML SSO Settings page.

A possible alternative is to use the SCIM API to manually retrieve the externalId we have stored for users, also called the external_uid or NameId.

To see how the external_uid compares to the value returned as the SAML NameId, you can have the user use a SAML Tracer.

Update or fix mismatched SCIM externalId and SAML NameId

Whether the value was changed or you need to map to a different field, ensure id, externalId, and NameId all map to the same field.

If the GitLab externalId doesn’t match the SAML NameId, it needs to be updated in order for the user to sign in. Ideally your identity provider is configured to do such an update, but in some cases it may be unable to do so, such as when looking up a user fails due to an ID change.

Be cautious if you revise the fields used by your SCIM identity provider, typically id and externalId. We use these IDs to look up users. If the identity provider does not know the current values for these fields, that provider may create duplicate users.

If the externalId for a user is not correct, and also doesn’t match the SAML NameID, you can address the problem in the following ways: