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This guide describes how Gitlab CE v13.x can be configured as a SAML Service Provider for eduTEAMS. The integration via SAML provides more benefits than the integration via OIDC, as the SAML OIDC implementation in Gitlab has (limited) support for authorizing users using groups. The OIDC implementation in Gitlab supports only authenticating users. |
CONFIGURE GROUPS
4. Congratulations, you have successfully configured your Gitlab instance for eduTEAMS. Now you can proceed to register your service following the steps described in Registering services on the eduTEAMS Service.
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This guide describes how Gitlab CE can be configured as a SAML Service Provider for eduTEAMS and it assumes:
- You are using Gitlab v13.x
- You have access to edit the Gitlab configuration file at /etc/gitlab/gitlab.rb
- The URL of your Gitlab instance is
https://gitlab.example.com/ - The name of your VO is Test_VO
It is possible to connect a Gitlab instance with eduTEAMS as a SAML Service Provider. The integration via SAML provides more benefits as the SAML implementation in Gitlab has (limited) support for authorizing users using groups. The OIDC implementation in Gitlab supports only authenticating users. As a reference this guide is available: https://docs.gitlab.com/13.0/ee/integration/saml.html .
In order to configure your Gitlab for eduTEAMS, you need the following information:
Configuration Option
Value
Description
(example) https://gitlab.example.com
https://proxy.acc.eduteams.org/saml2sp/sso/redirect
Basic integration
In the basic integration, all users from your VO will be able to authenticate via eduTEAMS and access the Gitlab service.
The "STEP nnn" comments refer directly to the OmniAuth guide (see the link at the start of this document).
Below is an example configuration:
/etc/gitlab/gitlab.rb
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# STEP 3gitlab_rails['omniauth_enabled'] = truegitlab_rails['omniauth_allow_single_sign_on'] = ['saml']gitlab_rails['omniauth_block_auto_created_users'] = false
# STEP 4gitlab_rails['omniauth_auto_link_saml_user'] = true
# STEP 6gitlab_rails['omniauth_providers'] = [ { name: 'saml', label: 'eduTEAMS', args: { assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback', idp_cert_fingerprint: '72:8A:6C:6B:63:35:3F:E0:BF:70:8D:41:0E:B7:02:CF:C5:86:53:24', idp_sso_target_url: 'https://proxy.eduteams.org/saml2sp/sso/redirect', issuer: 'https://gitlab.example.com', name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent', uid: ["urn:oasis:names:tc:SAML:attribute:subject-id"], email: ["urn:oid:0.9.2342.19200300.100.1.3",], first_name: ["urn:oid:2.5.4.42"], last_name: ["urn:oid:2.5.4.4"] }, groups_attribute: 'urn:oid:1.3.6.1.4.1.5923.1.1.1.7', required_groups: [], admin_groups: [], audit_groups: [] }]
Advanced integration
The SAML login in Gitlab includes support for limiting access to specific groups from your VO. You can control which groups can access the Gitlab instance using the required_groups configuration option. When required_groups is not set or it is empty, anyone with proper authentication will be able to use the service.
It is also possible to automatically identify whether a user should be considered an external user based on the user’s group membership in your VO in eduTEAMS This feature does not allow you to automatically add users to GitLab Groups, it simply allows you to mark users as External if they are members of certain groups of users. You can control the users of which groups will be marked as External using the the external_groups configuration option.
This setting works very similarly to the External Groups setting. The requirements are the same, your IdP needs to pass Group information to GitLab, you need to tell GitLab where to look for the groups in the SAML response, and which group should be considered admin groups
This setting also follows the requirements documented for the External Groups setting. GitLab uses the Group information provided by your IdP to determine if a user should be assigned the auditor role.
Below is an example configuration:
/etc/gitlab/gitlab.rb
CONFIGURE GROUPS
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# STEP 3gitlab_rails['omniauth_enabled'] = truegitlab_rails['omniauth_allow_single_sign_on'] = ['saml']gitlab_rails['omniauth_block_auto_created_users'] = false
# STEP 4gitlab_rails['omniauth_auto_link_saml_user'] = true
# STEP 6gitlab_rails['omniauth_providers'] = [ { name: 'saml', label: 'eduTEAMS', args: { assertion_consumer_service_url: 'https://gitlab.example.com/users/auth/saml/callback', idp_cert_fingerprint: '72:8A:6C:6B:63:35:3F:E0:BF:70:8D:41:0E:B7:02:CF:C5:86:53:24', idp_sso_target_url: 'https://proxy.eduteams.org/saml2sp/sso/redirect', issuer: 'https://example.gitlab.com', name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent', uid: ["urn:oasis:names:tc:SAML:attribute:subject-id"], email: ["urn:oid:0.9.2342.19200300.100.1.3",], first_name: ["urn:oid:2.5.4.42"], last_name: ["urn:oid:2.5.4.4"] },
# STEP(s) "Required Groups", "Admin Groups", "Auditor Groups" groups_attribute: 'urn:oid:1.3.6.1.4.1.5923.1.1.1.7', # Only the following groups in the Test_VO will be able to access this Gitlab instance: # # - Developers # - Admins:Gitlab # - Admins:Gitlab:Auditors required_groups: [ 'urn:geant:eduteams.org:service:eduteams:group:Test_VO:Developers#eduteams.org', 'urn:geant:eduteams.org:service:eduteams:group:Test_VO:Developers#eduteams.org', 'urn:geant:eduteams.org:service:eduteams:group:Test_VO:Admins:Gitlab#eduteams.org', 'urn:geant:eduteams.org:service:eduteams:group:Test_VO:Admin:Gitlab:Auditors#eduteams.org', ], # Users from the following groups in the Test_VO will access this Gitlab instance as admins # # - Admins:Gitlab: admin_groups: [ 'urn:geant:eduteams.org:service:eduteams:group:Test_VO:Admins:Gitlab#eduteams.org', ], # Users from the following groups in the Test_VO will access this Gitlab instance as auditors: # # - Admins:Gitlab:Auditors audit_groups: [ 'urn:geant:eduteams.org:service:eduteams:group:Test_VO:Admins:Gitlab:Auditors#eduteams.org', ], # Users from the following gorup in the Test_VO will access the Gitlab instance external users # # - Guests # - Contractors external_groups: [ 'urn:geant:eduteams.org:service:eduteams:group:Test_VO:Guests#eduteams.org', 'urn:geant:eduteams.org:service:eduteams:group:Test_VO:Conractors#eduteams.org',
], } }]
Next Steps
Check the SAML metadata URL of the Gitlab instance at https://gitlab.example.com/users/auth/saml/metadata (replace gitlab.example.com with the domain of your Gitlab instance). You should should something like the following:
Gitlab SAML Metadata
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<?xml version='1.0' encoding='UTF-8'?><md:EntityDescriptor ID="_9edb3dae-0919-40ff-b7c0-bffc63ba032b" entityID" xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata" xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"> <md:SPSSODescriptor AuthnRequestsSigned="false" WantAssertionsSigned="false" protocolSupportEnumerationprotocol"> <md:NameIDFormat>urn:oasis:names:tc:SAML:2.0:nameid-format:persistent</md:NameIDFormat> <md:AssertionConsumerService Bindingbindings:HTTP-POST" Location="https://gitlab.example.com/users/auth/saml/callback" index="0" isDefault="true" /> <md:AttributeConsumingService index="1" isDefault="true"> <md:ServiceName xml:lang="en">Required attributes</md:ServiceName> <md:RequestedAttribute FriendlyName="Email address" Name="email" basic false /> <md:RequestedAttribute Full name name" basic "false" /> <md:RequestedAttribute FriendlyName="Given name" Name="first_name" basic false /> <md:RequestedAttribute Family name last_name" basic false AttributeConsumingService> SPSSODescriptor>4. Congratulations
EntityDescriptor>Congratulations, you have successfully configured your Gitlab instance for eduTEAMS. Now you can proceed registering to register your service following the steps described in in Registering services on the eduTEAMS Service.