Configure OpenID Connect with ACL authorization

Uses: Kong Gateway decK
TL;DR

Using the OpenID Connect and ACL plugins, set up any type of authentication (the password grant, in this guide) and enable authorization through ACL groups.

Prerequisites

This is a Konnect tutorial. If you don’t have a Konnect account, you can get started quickly with our onboarding wizard.

  1. The following Konnect items are required to complete this tutorial:

    • Personal access token (PAT): Create a new personal access token by opening the Konnect PAT page and selecting Generate Token.
    • Control Plane Name: You can use an existing Control Plane or create a new one to use for this tutorial.
    • Konnect Proxy URL: By default, a self-hosted Data Plane uses http://localhost:8000. You can set up Data Plane nodes for your Control Plane from the Gateway Manager in Konnect.
  2. Set the personal access token, the Control Plane name, the Control Plane URL, and the Konnect proxy URL as environment variables:

     export DECK_KONNECT_TOKEN='YOUR KONNECT TOKEN'
     export DECK_KONNECT_CONTROL_PLANE_NAME='YOUR CONTROL PLANE NAME'
     export KONNECT_CONTROL_PLANE_URL=https://us.api.konghq.com
     export KONNECT_PROXY_URL='KONNECT PROXY URL'
    

This tutorial requires Kong Gateway Enterprise. If you don’t have Kong Gateway set up yet, you can use the quickstart script with an enterprise license to get an instance of Kong Gateway running almost instantly.

  1. Export your license to an environment variable:

     export KONG_LICENSE_DATA='LICENSE-CONTENTS-GO-HERE'
    
  2. Run the quickstart script:

     curl -Ls https://get.konghq.com/quickstart | bash -s -- -e KONG_LICENSE_DATA 
    

    Once Kong Gateway is ready, you will see the following message:

     Kong Gateway Ready
    

decK is a CLI tool for managing Kong Gateway declaratively with state files. To complete this tutorial you will first need to install decK.

For this tutorial, you’ll need Kong Gateway entities, like Gateway Services and Routes, pre-configured. These entities are essential for Kong Gateway to function but installing them isn’t the focus of this guide. Follow these steps to pre-configure them:

  1. Run the following command:

    echo '
    _format_version: "3.0"
    services:
      - name: example-service
        url: http://httpbin.konghq.com/anything
    routes:
      - name: example-route
        paths:
        - "/anything"
        service:
          name: example-service
    ' | deck gateway apply -
    

To learn more about entities, you can read our entities documentation.

This tutorial requires an identity provider (IdP). If you don’t have one, you can use Keycloak. The steps will be similar in other standard identity providers.

Create a client

  1. Install Keycloak (version 26 or later) on your platform.

    For example, you can use the Keycloak Docker image:

     docker run -p 8080:8080 \
       -e KC_BOOTSTRAP_ADMIN_USERNAME=admin \
       -e KC_BOOTSTRAP_ADMIN_PASSWORD=admin \
       quay.io/keycloak/keycloak start-dev
    
  2. Open the admin console.

    The default URL of the console is http://$YOUR_KEYCLOAK_HOST:8080/admin/master/console/.

  3. In the sidebar, open Clients, then click Create client.
  4. Configure the client:

Section

Settings

General settings
  • Client type: OpenID Connect
  • Client ID: any unique name, for example kong
Capability config
  • Toggle Client authentication to on
  • Make sure that Standard flow, Direct access grants, and Service accounts roles are checked.
Login settings Valid redirect URIs: http://localhost:8000/*

Set up keys and credentials

  1. In your client, open the Credentials tab.
  2. Set Client Authenticator to Client ID and Secret.
  3. Copy the Client Secret.
  4. Switch to the Users menu and add a user.
  5. Open the user’s Credentials tab and add a password. Be sure to disable Temporary Password.

In this guide, we’re going to use an example user named alex with the password doe.

Export to environment variables

Export your client secret, client ID, and issuer URL to environment variables so that you can pass them more securely. For example:

export DECK_ISSUER=http://host.docker.internal:8080/realms/master
export DECK_CLIENT_ID=kong
export DECK_CLIENT_SECRET=UNT3GPzCKI7zUbhAmFSUGbj4wmiBDGiW

Enable the OpenID Connect plugin

Using the Keycloak and Kong Gateway configuration from the prerequisites, set up an instance of the OpenID Connect plugin. In this example, we’re using the simple password grant with authenticated groups.

Enable the OpenID Connect plugin on the example-service Service:

echo '
_format_version: "3.0"
plugins:
  - name: openid-connect
    service: example-service
    config:
      issuer: "${{ env "DECK_ISSUER" }}"
      client_id:
      - "${{ env "DECK_CLIENT_ID" }}"
      client_secret:
      - "${{ env "DECK_CLIENT_SECRET" }}"
      client_auth:
      - client_secret_post
      auth_methods:
      - password
      authenticated_groups_claim:
      - scope
' | deck gateway apply -

In this example:

  • issuer, client ID, client secret, and client auth: Settings that connect the plugin to your IdP (in this case, the sample Keycloak app).
  • auth_methods: Specifies that the plugin should use the password grant, for easy testing.
  • authenticated_groups_claim: Looks for a groups claim in an ACL.

Note: Setting config.client_auth to client_secret_post lets you easily test the connection to your IdP, but we recommend using a more secure auth method in production. You can use any of the supported client auth methods.

Validate the OpenID Connect plugin configuration

Request the Service with the basic authentication credentials created in the prerequisites:

curl -i -X GET "$KONNECT_PROXY_URL/anything" \
     -u alex:doe
curl -i -X GET "http://localhost:8000/anything" \
     -u alex:doe

You should get an HTTP 200 response with an X-Authenticated-Groups header:

"X-Authenticated-Groups": "openid, email, profile"

Enable the ACL plugin and verify

Let’s try denying access to the openid group first:

echo '
_format_version: "3.0"
plugins:
  - name: acl
    service: example-service
    config:
      deny:
      - openid
' | deck gateway apply -

Try to access the /anything Route:

curl -i -X GET "$KONNECT_PROXY_URL/anything" \
     -u alex:doe
curl -i -X GET "http://localhost:8000/anything" \
     -u alex:doe

You should get a 403 Forbidden error code with the message You cannot consume this service.

Now let’s allow access to the openid group:

echo '
_format_version: "3.0"
plugins:
  - name: acl
    service: example-service
    config:
      allow:
      - openid
' | deck gateway apply -

And try accessing the /anything Route again:

curl -i -X GET "$KONNECT_PROXY_URL/anything" \
     -u alex:doe
curl -i -X GET "http://localhost:8000/anything" \
     -u alex:doe

This time, you should get a 200 response.

Cleanup

If you created a new control plane and want to conserve your free trial credits or avoid unnecessary charges, delete the new control plane used in this tutorial.

curl -Ls https://get.konghq.com/quickstart | bash -s -- -d
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