Keycloak Camunda Identity Provider Plugin

Keycloak™ (https://www.keycloak.org/) is an Open Source Identity and Access Management platform including advanced features such as User Federation, Identity Brokering and Social Login.

Camunda™ (https://camunda.com/) in it's current version is perfectly suited to carry out BPM projects in the cloud. Identity management in the cloud, however, often differs from classical approaches. Camunda already provides a generic sample for Single Sign On when using Spring Boot. See https://github.com/camunda-consulting/code/tree/master/snippets/springboot-security-sso. Specific instructions on how to use Spring Boots OAuth2 SSO in combination with this Keycloak Identity Provider Plugin can be found below.

Why this plugin? SSO is sufficient in case you only want authentication but have no further advanced security roles. If one needs to use Camundas IdentityService APIs or wants to see actual Users and Groups show up in Cockpit, a custom IdentityProvider needs to be implemented as well.

This plugin provides the basis for using Keycloak as Identity Management solution and will provide a ReadOnlyIdentityProvider. What you will get is a fully integrated solution for using Keycloak as an Identity Provider in Camunda receiving users and groups from Keycloak. The authorization of these users and groups for Camunda resources itself remains within Camunda. This plugin allows the usage of Keycloak as Identity Provider even without SSO.

Beware: in case you want to use Keycloak's advanced login capabilities for social connections you must configure SSO as well. Password grant exchanges are only supported for Keycloak's internally managed users and users of an LDAP / Keberos User federation. Hence without SSO you will only be able to login with users managed by such connections.

Current version: 1.4.0
Tested with: Keycloak >= 5.0.0, Camunda >= 7.10.0, 7.10.0-ee

Features

New in Version 1.4.0:

• Corrected rare problems with group queries of a single user in case the Keycloak Client name is similar to this username and config property useUsernameAsCamundaUserId=true

New in Version 1.3.0:

• Provided additional fat camunda-bpm-identity-keycloak-all.jar including transitive dependencies for easier installation e.g. on Apache Tomcat distribution with shared engine.

New in Version 1.2.0:

• Optimized and correct searches in Keycloak mass data
• Add missing paging functionality to queries

New in Version 1.1.0:

• Ability to read group hierarchies.
• New option useGroupPathAsCamundaGroupId for readable group IDs. Helps when configuring authorizations.

Version 1.0.0:

• ReadOnlyIdentityProvider
• Broad support for user and group queries
• Compatible with Spring Boot OAuth2 SSO

Known limitations:

• A strategy to distinguish SYSTEM and WORKFLOW groups is missing. Currently only the administrator group is mapped to type SYSTEM.
• Some query filters are applied on the client side - the Keycloak REST API does not allow full criteria search in all required cases.
• Sort criteria for queries are implemented on the client side - the Keycloak REST API does not allow result ordering.
• Tenants are currently not supported.

Prerequisites in your Keycloak realm

1. Keycloak docker images can be found on Keycloak Docker Hub.
2. Create a new client named camunda-identity-service with access type confidential and service accounts enabled:
3. Add the roles query-groups, query-users, view-users to the service account client roles of your realm (master-realm or realm-management, depending on whether you are using master or a separate realm):
4. Your client credentials can be found here:
5. Once you're done with the basic setup you're now ready to manage your users and groups with Keycloak. Please keep in mind, that in order to make the Keycloak Identity Provider work, you will need at least one dedicated Camunda admin group or Camunda admin user in your realm. Whether you create this group/user manually or import it using the LDAP user federation or any other Identity Provider is up to you.

Usage with Camunda Spring Boot

Maven Dependencies:

	<dependency>
		<groupId>org.camunda.bpm.extension</groupId>
		<artifactId>camunda-bpm-identity-keycloak</artifactId>
		<version>1.4.0</version>
	</dependency>

Add the following class to your Camunda Spring Boot application in order to activate the Keycloak Identity Provider Plugin:

package <your-package>;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import org.camunda.bpm.extension.keycloak.plugin.KeycloakIdentityProviderPlugin;

@Component
@ConfigurationProperties(prefix="plugin.identity.keycloak")
public class KeycloakIdentityProvider extends KeycloakIdentityProviderPlugin {
}

Configuration in application.yaml will then look as follows:

camunda.bpm:
  ...
  authorization:
    enabled: true

plugin.identity.keycloak:
  keycloakIssuerUrl: https://<your-keycloak-server>/auth/realms/<realm-name>
  keycloakAdminUrl: https://<your-keycloak-server>/auth/admin/realms/<realm-name>
  clientId: camunda-identity-service
  clientSecret: 42aa42bb-1234-4242-a24a-42a2b420cde0
  useEmailAsCamundaUserId: true
  administratorGroupName: camunda-admin

Hint: the engine must not create a user upon startup - the plugin is a ReadOnlyIdentityProvider. Hence you must not configure an admin-user for camunda.bpm in your application.yaml. The following configuration will likely cause errors upon startup:

camunda.bpm:
  # DON'T DO THIS
  admin-user:
    id: demo
    password: demo
    firstName: Camunda

The admin-user part must be deleted in order to work properly. The recommended procedure for creating the admin user and admin group in Keycloak is to have the deployment pipeline do this during the environment setup phase.

A complete list of configuration options can be found below:

Property	Description
keycloakIssuerUrl	The basic issuer URL of your Keycloak server including the realm. Sample for master realm: https://<your-keycloak-server>/auth/realms/master
keycloakAdminUrl	The admin URL of the Keycloak server REST API including the realm. Sample for master realm: https://<your-keycloak-server>/auth/admin/realms/master
clientId	The Client ID of your application.
clientSecret	The Client Secret of your application.
useEmailAsCamundaUserId	Whether to use the Keycloak email attribute as Camunda's user ID. Default is false. This is option is a fallback in case you don't use SSO and want to login using Camunda's web interface with your mail address and not the cryptic internal Keycloak ID. Keep in mind that you will only be able to login without SSO with Keycloak's internally managed users and users managed by the LDAP / Keberos User federation.
useUsernameAsCamundaUserId	Whether to use the Keycloak username attribute as Camunda's user ID. Default is false. In the default case the plugin will use the internal Keyclaok ID as Camunda's user ID.
useGroupPathAsCamundaGroupId	Whether to use the Keycloak unique group path as Camunda's group ID. Default is false. In the default case the plugin will use the internal Keycloak ID as Camunda's group ID. This flag is particularly useful in case you want to have human readable group IDs and recommended when using groups in Camunda's authorization management. Since 1.1.0
administratorGroupName	The name of the administrator group. If this name is set and engine authorization is enabled, the plugin will create group-level Administrator authorizations on all built-in resources.
administratorUserId	The ID of the administrator user. If this ID is set and engine authorization is enabled, the plugin will create user-level Administrator authorizations on all built-in resources.
authorizationCheckEnabled	If this property is set to true, then authorization checks are performed when querying for users or groups. Otherwise authorization checks are not performed when querying for users or groups. Default: true. Note: If you have a huge amount of Keycloak users or groups we advise to set this property to false to improve the performance of the user and group query.
maxHttpConnections	Maximum number HTTP connections for the Keycloak connection pool. Default: 50
disableSSLCertificateValidation	Whether to disable SSL certificate validation. Default: false. Useful in test environments.

Activating Single Sign On

In this part, we’ll discuss how to activate SSO – Single Sign On – for the Camunda Web App using Spring Boots Security OAuth2 capabilities in combination with this plugin and Keycloak as authorization server.

In order to setup Spring Boot's OAuth2 security add the following Maven dependencies to your project:

	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-security</artifactId>
	</dependency>
	<dependency>
		<groupId>org.springframework.security.oauth.boot</groupId>
		<artifactId>spring-security-oauth2-autoconfigure</artifactId>
		<version>2.1.5.RELEASE</version>
	</dependency>

Insert a KeycloakAuthenticationProvider as follows:

/**
 * OAuth2 Authentication Provider for usage with Keycloak and KeycloakIdentityProviderPlugin. 
 */
public class KeycloakAuthenticationProvider extends ContainerBasedAuthenticationProvider {

    @Override
    public AuthenticationResult extractAuthenticatedUser(HttpServletRequest request, ProcessEngine engine) {

    	// Extract authentication details
        OAuth2Authentication authentication = (OAuth2Authentication) SecurityContextHolder.getContext().getAuthentication();
        if (authentication == null) {
            return AuthenticationResult.unsuccessful();
        }
        Authentication userAuthentication = authentication.getUserAuthentication();
        if (userAuthentication == null || userAuthentication.getDetails() == null) {
            return AuthenticationResult.unsuccessful();
        }
        
        // Extract user ID from Keycloak authentication result - which is part of the requested user info
        @SuppressWarnings("unchecked")
        String userId = ((HashMap<String, String>) userAuthentication.getDetails()).get("sub");
        // String userId = ((HashMap<String, String>) userAuthentication.getDetails()).get("email"); // useEmailAsCamundaUserId = true
        // String userId = ((HashMap<String, String>) userAuthentication.getDetails()).get("preferred_username"); // useUsernameAsCamundaUserId = true
        if (StringUtils.isEmpty(userId)) {
            return AuthenticationResult.unsuccessful();
        }

        // Authentication successful
        AuthenticationResult authenticationResult = new AuthenticationResult(userId, true);
        authenticationResult.setGroups(getUserGroups(userId, engine));

        return authenticationResult;
    }

    private List<String> getUserGroups(String userId, ProcessEngine engine){
        List<String> groupIds = new ArrayList<>();
        // query groups using KeycloakIdentityProvider plugin
        engine.getIdentityService().createGroupQuery().groupMember(userId).list()
        	.forEach( g -> groupIds.add(g.getId()));
        return groupIds;
    }

}

Last but not least add a security configuration and enable OAuth2 SSO:

/**
 * Camunda Web application SSO configuration for usage with KeycloakIdentityProviderPlugin.
 */
@Configuration
@EnableOAuth2Sso
public class WebAppSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
    	http
    	.csrf().ignoringAntMatchers("/api/**")
    	.and()
        .antMatcher("/**")
        .authorizeRequests()
          .antMatchers("/app/**")
          .authenticated()
        .anyRequest()
          .permitAll()
        ;
    }

    @SuppressWarnings({ "rawtypes", "unchecked" })
    @Bean
    public FilterRegistrationBean containerBasedAuthenticationFilter(){

        FilterRegistrationBean filterRegistration = new FilterRegistrationBean();
        filterRegistration.setFilter(new ContainerBasedAuthenticationFilter());
        filterRegistration.setInitParameters(Collections.singletonMap("authentication-provider", "<your-package>.sso.KeycloakAuthenticationProvider"));
        filterRegistration.setOrder(101); // make sure the filter is registered after the Spring Security Filter Chain
        filterRegistration.addUrlPatterns("/app/*");
        return filterRegistration;
    }

	@Bean
	public RequestContextListener requestContextListener() {
		return new RequestContextListener();
	}
}

Finally configure Spring Security with your Keycloak Single Page Web App client-id and client-secret in application.yaml as follows:

security:
  oauth2:
    client:
      client-id: camunda-identity-service
      client-secret: yyy2121abc21def2121ghi212132121abc21def2121ghi2121eyyy
      accessTokenUri: https://<your-keycloak-server>/auth/realms/<realm-name>/protocol/openid-connect/token
      userAuthorizationUri: https://<your-keycloak-server>/auth/realms/<realm-name>/protocol/openid-connect/auth
      scope: openid profile email
    resource:
      userInfoUri: https://<your-keycloak-server>/auth/realms/<realm-name>/protocol/openid-connect/userinfo

Beware: SSO will only work that way in case you have the KeycloakIdentityProviderPlugin's property useEmailAsCamundaUserId set to default which is false. If you want to use the email attribute as Camunda's user ID, the extraction in the Authentication Provider must be implemented as follows:

// Extract email from Keycloak authentication result - which is part of the requested user info
@SuppressWarnings("unchecked")
String userId = ((HashMap<String, String>) userAuthentication.getDetails()).get("email");

Keep in mind that Keycloak's ID is definitely unique which might not always be the case for the email attribute, depending on your setup. Email uniqueness can be configured on a per realm level depending on the setting Login with email.

In case you have activated the flag useUsernameAsCamundaUserId the extraction in the Authentication Provider must be changed in a similar way and can be implemented as follows:

// Extract username from Keycloak authentication result - which is part of the requested user info
@SuppressWarnings("unchecked")
String userId = ((HashMap<String, String>) userAuthentication.getDetails()).get("preferred_username");

Sample Spring Boot Project with SSO on Kubernetes

A sample project using this plugin including a basic SSO and Kubernetes setup can be found under Camunda Showcase for Spring Boot & Keycloak Identity Provider. See directory examples.

Installation on Apache Tomcat with Shared Process Engine

Even if from an architectural point of view Spring Boot is currently the most recommended approach for cloud scenarios, it is of course possible to install the plugin in other Camunda distributions as well. A description on how to install the plugin on an Apache Tomcat full distribution can be found under Installation on Tomcat. See directory examples.

Unit testing the plugin

In order to run the unit tests I have used a local docker setup of Keycloak with docker-compose.yml as follows:

version: "3.3"

services:
  jboss.keycloak:
    build: .
    image: jboss/keycloak
    restart: always
    environment:
      TZ: Europe/Berlin
      KEYCLOAK_USER: keycloak
      KEYCLOAK_PASSWORD: keycloak1!
    ports:
      - "8443:8443"

For details see documentation on Keycloak Docker Hub.

Maven test setup

Running unit tests from Maven requires configuring the details of a running Keycloak server. This can be achieved by setting the following environment variables:

Environment Variable	Description
KEYCLOAK_URL	Keycloak server URL. Default value: https://localhost:8443/auth
KEYCLOAK_ADMIN_USER	The admin user of the Keycloak server. Default value: keycloak
KEYCLOAK_ADMIN_PASSWORD	The admin password of the Keycloak server. Default value: keycloak1!

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License: Apache License 2.0

That's it. Have a happy Keycloak experience and focus on what really matters: the core processes of your customer.

Brought to you by:

Gunnar von der Beck, Accso - Accelerated Solutions GmbH