Keycloak integration with OpenFGA (based on Zanzibar) for Fine-Grained Authorization at Scale (ReBAC)

This repository contains a PoC implemented with Keycloak integrated with OpenFGA on demostrating how to apply fine-grained access control in a high performance and flexible authorization.

This workshop is based the following article Keycloak integration with OpenFGA (based on Zanzibar) for Fine-Grained Authorization at Scale (ReBAC). You will find there full details about the authorization architecture guidelines and involved components.

Authorization Framework

The following diagram illustrates the solution architecture of this workshop:

Core:
- Keycloak (A) is responsible for handling the authentication with the standard OpenID Connect and is managing the user access with his Role Model
- Keycloak is configure with a custom extension (B) keycloak-openfga-event-listener which listens to the Keycloak events (User Role Assignment, Role to Role Assignment, etc), parses this event into an OpenFGA tuple based on the Keycloak Authz Schema and publishes the event to Kakfa Cluster (C)
- Kakfa OpenFGA Consumer (D) that using the OpenFGA SDK will publish the tuples to the OpenFGA Solution
- OpenFGA (E) is responsible for applying fine-grained access control. The OpenFGA service answers authorization checks by determining whether a relationship exists between an object and a user
Other components
- Store Web Application is integrated with Keycloak by OpenID Connect
- Store API is protected by OAuth 2.0 and it utilizes the OpenFGA SDK for FGA

So far we don’t have an official Java SDK OpenFGA client to publish the authorization tuples. This is why I decided to use an Apache Kafka cluster for managing the events. Nevertheless, the extension is prepared for the future to use an http client for publishing the events.

How to install?

Prerequisites

Install Git, Docker and Docker Compose in order to run the steps provided in the next section

Deploy the PoC

Clone this repository

git clone https://github.com/embesozzi/keycloak-openfga-workshop
cd keycloak-openfga-workshop

Execute following Docker Compose command to start the deployment

docker-compose -f docker-compose.yml -f docker-compose-apps.yml up

To be able to use this environment, you need to add this line to your local HOSTS file:
```
127.0.0.1  keycloak openfga store store-api
```

Access the following web UIs using URLs bellow via a web browser.

Component	URI	Username	Password	Image
Keycloak Console	http://keycloak:8081	admin	password	quay.io/keycloak/keycloak:19.0.2
OpenFGA Playground	http://localhost:3000/playground			openfga/openfga:latest
OpenFGA API	http://localhost:8080			confluentinc/cp-zookeeper:7.2.2 confluentinc/cp-kafka:7.2.2
Store Portal	http://store:9090			Custom image
Store API	http://store-api:9091			Custom image

Post configuration steps

OpenFGA

Import the OpenFGA authorization schema for Keycloak:
```
cd openfga
./import.sh
```
As the result you will see the following OpenFGA Authorization Model in the OpenFGA Playground Console :

Keycloak

Enable the Keycloak OpenFGA Event Listener extension in Keycloak:
- Open administration console
- Choose realm
- Realm settings
- Select Events tab and add openfga-events to Event Listeners.

Proceed to initialize the PoC:

Execute the following script to initialize the PoC:

docker exec keycloak /bin/bash /opt/keycloak/initialize-poc.sh

This script will create the OAuth Clients and the following Users and Role Model:

The password for all the users is demo1234!

Once these steps are finished, the Keycloak OpenFGA Event Listener extension has to proceed to publish these events to the Kafka topic called “openfga-topic”. Then, the Kafka consumer has published those events to the OpenGFA store using the SDK. Here are all tuples stored.

User	Relation	Object
role:admin-catalog	parent	role:view-product
role:analyst-catalog	parent	role:view-product
role:admin-catalog	parent	role:edit-product
user:paula	assignee	role:analyst-catalog
user:richard	assignee	role:admin-catalog

The users are identified by the value of the claim sub in the OpenFGA Playground, see the Tuples tab:

Restart the apps (containers: store and store-api)

Test cases

As an example, we will implement an Product Catalog web application that has the following requirements:

Only authenticated user with MFA can access to the application
Product can be viewed by their Analyst
Product can be edited by their Admin
Global Admin users can view or edit any Product

You can follow the test cases described in the Keycloak integration with OpenFGA (based on Zanzibar) for Fine-Grained Authorization at Scale (ReBAC).

Nevertheless, the use cases are detailed below:

Use case 1: Access to the Store for managing products as an Analyst (Paula)

Access to the store web application store web application and proceed to login with Paula (paula / demo1234!) in Keycloak.
Keycloak will return the id_token and the access token to the application
The Store web application will show the product catalog

3.1. The app will call the product API sending the access token in the Authorization header

3.2. The API will apply the following steps:

3.3. It will validate the token following the OAuth 2.0 standard and it will extract the claim sub to identify the user

3.4. Then it will call the OpenFGA API to check if the user has the view-product role with the relationship assignee

3.5. OpenFGA will return the response “allowed”

3.6. The API will return the product information and the Store web app will show the product catalog to the user
Try to publish a product by clicking the button "Publish" but you will see that Paula is not allowed

4.1. The app will call the product API sending the access token in the Authorization header

4.2. The API will apply the following steps:

4.3. It will validate the token following the OAuth 2.0 standard and it will extract the claim sub to identify the user

4.4. Then it will call the OpenFGA API to check if the user has the edit-product role with the relationship assignee

4.5. OpenFGA will return the response “denied”

Use case 2: Access to the Store for managing products as an Admin (Richard)

Access to the store web application store web application and proceed to login with Richard (richard / demo1234!) in Keycloak.
Keycloak will return the id_token and the access token to the application
The store web application will show the product catalog
Try to publish a product by clicking the button "Publish" but you will see that Richard is allowed

Use case 3: Access to the Store for managing products as an Regular User (Peter)

Access to the store web application store web application and proceed to login with Peter (peter / demo1234!) in Keycloak.
Keycloak will return the id_token and the access token to the application
The store web application will try to the products show but the user is not allowed

DGuhr / keycloak-openfga-workshop