Configuring OAuth Authentication

This topic describes how to configure your team's authentication using OAuth Authentication.

Overview

Continuous integration servers often contain many secrets that let them access source code and deploy apps. It is important that those secrets remain well guarded. Concourse provides options for both authentication and authorization to give you control over who can access your server and how much they can see.

Any number of the following providers can be enabled at any one time. Users are given a choice when logging in as to which one they want to use.

Note If you access your Concourse server over the public internet, then consider using TLS to secure your connection to the web node.

Configuring team authentication in Concourse is done in two parts:

1. Configure the allowed authentication providers in the deployment manifest. See Configure Authentication Providers below.
2. Add users and groups to Concourse teams using fly set-team. See Add Users and Groups to Teams below.

Configure Authentication Providers

Concourse can be configured to use local users, GitHub, generic LDAP, Cloud Foundry, OAuth, and OIDC as authentication providers. You must specify the allowed authentication providers before Concourse is deployed.

A Concourse operator needs to provide the following information in their Concourse deployment manifest:

• A list of allowed local users
• Configurations against third-party authentication providers (GitHub, generic LDAP, Cloud Foundry, OAuth, and OIDC)
• Users who should be members of the default main team (either local users or users/groups from external authentication providers)

OAuth Authentication

If your authentication provider supports OAuth2 but does not follow the OIDC specification, then use this provider. This provider gives you more control over the OIDC provider by letting operators specify the full set of authorization endpoints (auth-url, token-url).

To add the OAuth provider, do the following:

1. Create the OIDC client.
2. Configure the client.

Create the OAuth Client

First, you need to create a client with your OAuth provider.

The callback URL is the external URL of your Concourse server with /sky/issuer/callback appended. For example, Concourse's own CI server's callback URL is https://ci.concourse-ci.org/sky/issuer/callback.

Configure the Client

To configure the OAuth provider, fill in the generic_oauth fields in the atc job of the manifest. For more information about these fields, see generic_oauth in the BOSH documentation.

The Main Team

By default, Concourse comes with a single team called main. The main team is an admin team. This means it can create and update other teams. Currently there is no way to promote a team to become an admin team, so main is a special team.

Concourse requires you to specify at least one user/group to be a member of the main team during deployment. The list of allowed users, groups, and orgs are managed through the main_team property in the ATC job. For more information about this property, see main_team in the BOSH documentation.

An example of adding a local user to the main team can be found in the add-local-users.yml file in the concourse-bosh-deployment GitHub repository.

The values set in the authentication flags take effect whenever the ATC starts up. This allows Concourse to be deployed against declared configurations. It also makes sure that members of the main team do not get locked out of their Concourse.

Add Users and Groups to Teams

After you deploy Concourse with the authentication providers configured, you can specify allowed users and groups using the fly set-team command. With this command, users and groups can be:

• Added to new teams
• Modified on existing teams

For more information about this command, see the Concourse documentation.

Note The exception to this is the main team. Members of the main team are configured as part of the initial deployment and cannot be changed after the deployment. For more information about the main team, see the Concourse documentation.

OAuth Users and Groups

Configure users and groups from a generic OAuth provider.

You can only configure groups if the authentication provider exposes this information in either the token itself or in the contents of the userinfo endpoint. You can configure which claim points to the group's information by specifying the groups-key at startup.

• Use --cf-user=USERNAME to authorize an individual user.
• Use --cf-org=ORG-NAME to authorize an entire org's members.
• Use --cf-space=ORG_NAME:SPACE-NAME to authorize the members of a space within an org.

For example:

$ fly set-team -n my-team \
    --oauth-user my-username \
    --oauth-group my-group

Team Configuration Details

Team members can view the authentication settings of the teams they belong to by using the fly teams -d command.

For example, the command below:

$ fly -t prod teams -d

The output is similar to the following:

name     users          groups
main     oauth:User     oauth:Group

Set User Roles and Permissions

Concourse v5.2.0 now has five roles with varying levels of permission. These are described in the table below:

Role	Description
Admin	Admin is a special user attribute granted to owners of the main team. Admins can administer teams using fly set-team, fly destroy-team, and fly rename-team. For more information about the main team, see The Main Team.
Team Owner	Team owners can read, write, and manage authentication capabilities within the scope of their team. They cannot rename or destroy the team.
Team Member	Team members can perform read and write actions within their team. They cannot change their team configuration.
Pipeline Operator	Team pipeline operators can perform pipeline operations such as triggering builds and pinning resources. They cannot update pipeline configurations.
Viewer	Team viewers have read-only access to a team and its pipelines. They cannot perform actions such as fly set-pipeline or fly intercept.

For a full list of permissions granted to each user role, see the Concourse documentation.

By default, the authentication config passed to set-team configures the member role. In addition, the existing team authentication config transitions to the team owner role.

In other words, anyone who could authenticate before the upgrade now authenticates as an owner of their team. This role is the closest equivalent to what they could do before.

More advanced roles configuration can be specified through the --configuration or --c flag.

The -c flag expects a YAML file with a single field, roles:. The roles field points to a list of role authentication configs.

The attributes in each config vary by provider. For specifics of your chosen provider, see Add Users to Groups and Teams above.

For example, the following config sets three roles with different CF authentication configs for each role's provider:

roles:
- name: owner
  cf:
    users: ["admin"]
- name: member
  cf:
    orgs: ["my-team"]
- name: viewer
  cf:
    spaces: ["org:my-other-team"]
  local:
    users: ["visitor"]