• Configuration
  • Allow external authorization with deploy tokens and deploy keys
• How it works
• Classification labels

External authorization control

In highly controlled environments, it may be necessary for access policy to be controlled by an external service that permits access based on project classification and user access. GitLab provides a way to check project authorization with your own defined service.

After the external service is configured and enabled, when a project is accessed, a request is made to the external service with the user information and project classification label assigned to the project. When the service replies with a known response, the result is cached for six hours.

If the external authorization is enabled, GitLab further blocks pages and functionality that render cross-project data. That includes:

• Most pages under Dashboard (Activity, Milestones, Snippets, Assigned merge requests, Assigned issues, To-Do List).
• Under a specific group (Activity, Contribution analytics, Issues, Issue boards, Labels, Milestones, Merge requests).
• Global and Group search are disabled.

This is to prevent performing too many requests at once to the external authorization service.

Whenever access is granted or denied this is logged in a log file called external-policy-access-control.log. Read more about the logs GitLab keeps in the Linux package documentation.

When using TLS Authentication with a self signed certificate, the CA certificate needs to be trusted by the OpenSSL installation. When using GitLab installed using the Linux package, learn to install a custom CA in the Linux package documentation. Alternatively, learn where to install custom certificates by using openssl version -d.

Configuration

The external authorization service can be enabled by an administrator:

1. On the left sidebar, at the bottom, select Admin.
2. Select Settings > General.
3. Expand External authorization.
4. Complete the fields.
5. Select Save changes.

Allow external authorization with deploy tokens and deploy keys

You can set your instance to allow external authorization for Git operations with deploy tokens or deploy keys.

Prerequisites:

• You must be using classification labels without a service URL for external authorization.

To allow authorization with deploy tokens and keys:

1. On the left sidebar, at the bottom, select Admin.
2. Select Settings > General.
3. Expand External authorization, and:
   • Leave the service URL field empty.
   • Select Allow deploy tokens and deploy keys to be used with external authorization.
4. Select Save changes.

How it works

When GitLab requests access, it sends a JSON POST request to the external service with this body:

{
  "user_identifier": "jane@acme.org",
  "project_classification_label": "project-label",
  "user_ldap_dn": "CN=Jane Doe,CN=admin,DC=acme",
  "identities": [
    { "provider": "ldap", "extern_uid": "CN=Jane Doe,CN=admin,DC=acme" },
    { "provider": "bitbucket", "extern_uid": "2435223452345" }
  ]
}

The user_ldap_dn is optional and is only sent when the user is signed in through LDAP.

identities contains the details of all the identities associated with the user. This is an empty array if there are no identities associated with the user.

When the external authorization service responds with a status code 200, the user is granted access. When the external service responds with a status code 401 or 403, the user is denied access. In any case, the request is cached for six hours.

When denying access, a reason can be optionally specified in the JSON body:

{
  "reason": "You are not allowed access to this project."
}

Any other status code than 200, 401 or 403 also deny access to the user, but the response isn’t cached.

If the service times out (after 500 ms), a message “External Policy Server did not respond” is displayed.

Classification labels

You can use your own classification label in the project’s Settings > General > General project settings page in the “Classification label” box. When no classification label is specified on a project, the default label defined in the global settings is used.

On all project pages, in the upper-right corner, the label appears.