debian-mirror-gitlab/doc/user/group/saml_sso/group_sync.md

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SAML Group Sync (PREMIUM)

Introduced for self-managed instances in GitLab 15.1.

WARNING: Changing Group Sync configuration can remove users from the mapped GitLab group. Removal happens if there is any mismatch between the group names and the list of groups in the SAML response. If changes must be made, ensure either the SAML response includes the groups attribute and the AttributeValue value matches the SAML Group Name in GitLab, or that all groups are removed from GitLab to disable Group Sync.

For a demo of Group Sync using Azure, see Demo: SAML Group Sync.

Configure SAML Group Sync

To configure SAML Group Sync:

• For GitLab self-managed:
  1. Configure the SAML OmniAuth Provider.
  2. Ensure your SAML identity provider sends an attribute statement with the same name as the value of the groups_attribute setting.
• For GitLab.com:
  1. See SAML SSO for GitLab.com groups.
  2. Ensure your SAML identity provider sends an attribute statement named Groups or groups.

NOTE: The value for Groups or groups in the SAML response can be either the group name or the group ID.

<saml:AttributeStatement>
  <saml:Attribute Name="Groups">
    <saml:AttributeValue xsi:type="xs:string">Developers</saml:AttributeValue>
    <saml:AttributeValue xsi:type="xs:string">Product Managers</saml:AttributeValue>
  </saml:Attribute>
</saml:AttributeStatement>

Other attribute names such as http://schemas.microsoft.com/ws/2008/06/identity/claims/groups are not accepted as a source of groups. See examples for configuring the required attribute name in the SAML identity provider's settings.

Configure SAML Group Links

When SAML is enabled, users with the Maintainer or Owner role see a new menu item in group Settings > SAML Group Links. You can configure one or more SAML Group Links to map a SAML identity provider group name to a GitLab role. This can be done for a top-level group or any subgroup.

To link the SAML groups:

1. In SAML Group Name, enter the value of the relevant saml:AttributeValue.
2. Choose the role in Access Level.
3. Select Save.
4. Repeat to add additional group links if required.

If a user is a member of multiple SAML groups mapped to the same GitLab group, the user gets the highest role from the groups. For example, if one group is linked as Guest and another Maintainer, a user in both groups gets the Maintainer role.

Users granted:

• A higher role with Group Sync are displayed as having direct membership of the group.
• A lower or the same role with Group Sync are displayed as having inherited membership of the group.

Automatic member removal

After a group sync, for GitLab subgroups, users who are not members of a mapped SAML group are removed from the group.

FLAG: In GitLab 15.1 and later, on GitLab.com, users in the top-level group are assigned the default membership role rather than removed. This setting is enabled with the saml_group_sync_retain_default_membership feature flag and can be configured by GitLab.com administrators only.

For example, in the following diagram:

• Alex Garcia signs into GitLab and is removed from GitLab Group C because they don't belong to SAML Group C.
• Sidney Jones belongs to SAML Group C, but is not added to GitLab Group C because they have not yet signed in.

graph TB
   subgraph SAML users
      SAMLUserA[Sidney Jones]
      SAMLUserB[Zhang Wei]
      SAMLUserC[Alex Garcia]
      SAMLUserD[Charlie Smith]
   end

   subgraph SAML groups
      SAMLGroupA["Group A"] --> SAMLGroupB["Group B"]
      SAMLGroupA --> SAMLGroupC["Group C"]
      SAMLGroupA --> SAMLGroupD["Group D"]
   end

   SAMLGroupB --> |Member|SAMLUserA
   SAMLGroupB --> |Member|SAMLUserB

   SAMLGroupC --> |Member|SAMLUserA
   SAMLGroupC --> |Member|SAMLUserB

   SAMLGroupD --> |Member|SAMLUserD
   SAMLGroupD --> |Member|SAMLUserC

graph TB
    subgraph GitLab users
      GitLabUserA[Sidney Jones]
      GitLabUserB[Zhang Wei]
      GitLabUserC[Alex Garcia]
      GitLabUserD[Charlie Smith]
    end

   subgraph GitLab groups
      GitLabGroupA["Group A (SAML configured)"] --> GitLabGroupB["Group B (SAML Group Link not configured)"]
      GitLabGroupA --> GitLabGroupC["Group C (SAML Group Link configured)"]
      GitLabGroupA --> GitLabGroupD["Group D (SAML Group Link configured)"]
   end

   GitLabGroupB --> |Member|GitLabUserA

   GitLabGroupC --> |Member|GitLabUserB
   GitLabGroupC --> |Member|GitLabUserC

   GitLabGroupD --> |Member|GitLabUserC
   GitLabGroupD --> |Member|GitLabUserD

graph TB
   subgraph GitLab users
      GitLabUserA[Sidney Jones]
      GitLabUserB[Zhang Wei]
      GitLabUserC[Alex Garcia]
      GitLabUserD[Charlie Smith]
   end

   subgraph GitLab groups after Alex Garcia signs in
      GitLabGroupA[Group A]
      GitLabGroupA["Group A (SAML configured)"] --> GitLabGroupB["Group B (SAML Group Link not configured)"]
      GitLabGroupA --> GitLabGroupC["Group C (SAML Group Link configured)"]
      GitLabGroupA --> GitLabGroupD["Group D (SAML Group Link configured)"]
   end

   GitLabGroupB --> |Member|GitLabUserA
   GitLabGroupC --> |Member|GitLabUserB
   GitLabGroupD --> |Member|GitLabUserC
   GitLabGroupD --> |Member|GitLabUserD

Use the API

Introduced in GitLab 15.3.

You can use the GitLab API to list, add, and delete SAML group links.

Troubleshooting

This section contains possible solutions for problems you might encounter.

User that belongs to many SAML groups automatically removed from GitLab group

When using Azure AD as the SAML identity provider, users that belong to many SAML groups can be automatically removed from your GitLab group. Users are removed from GitLab groups if the group claim is missing from the user's SAML assertion.

Because of a known issue with Azure AD, if a user belongs to more than 150 SAML groups, the group claim is not sent in the user's SAML assertion.

To work around this issue, allow more than 150 group IDs to be sent in SAML token using configuration steps in the Azure AD documentation.