Keycloak Integration with Spring Security

Introduction

This Spring Boot project demonstrates web and method security using ct-iam-spring-security. This repository is only available to sponsors (Anbu level).

How it Works

Maven Dependency

This module is available in GitHub and can be added to your Maven project as a dependency.

<dependency>
  <groupId>com.czetsuyatech</groupId>
  <artifactId>ct-iam-spring-security</artifactId>
  <version>${ct-iam-spring-security.version}</version>
</dependency>

Make sure to define the ct-iam-spring-security.version property with the latest release version.

Security Configuration Data

Cognito

We need to define the following Spring application configs to connect to our AWS Cognito instance to decode and verify the JWT token.

app:
  security:
    jwt:
      keycloak:
        realm: czetsuyatech

spring:
  security:
    oauth2:
      resourceserver:
        jwt:
          issuer-uri: http://localhost:8080/auth/realms/${app.security.jwt.keycloak.realm}

Enabling Web and Method Security

To enable the web and method security in your microservice. Create a new Java class CtAppSecurityConfiguration and annotate it with EnableCtSecurity. In this class, we define the custom beans that generates the HttpSecurity and add it to the filter chain as well as the custom method security expression handler.

@Configuration
@RequiredArgsConstructor
@EnableCtSecurity
public class CtAppSecurityConfiguration {

  @Bean
  public CtHttpSecurityConfigurer httpSecurityConfig() {

    return http ->
        http
            .authorizeHttpRequests(authz -> authz
                .antMatchers(HttpMethod.GET, "/actuator/**").permitAll()
                .antMatchers("/api/**").authenticated()
                .anyRequest().permitAll()
            );
  }

  @Bean
  public CtMethodSecurityExpressionHandlerFactory methodSecurityFactory() {
    return CtAppMethodSecurityExpressionRoot::new;
  }
}

In CtWebSecurityConfiguration:

@Configuration
@EnableWebSecurity
@RequiredArgsConstructor
public class CtWebSecurityConfiguration {

  private final CtHttpSecurityConfigurer httpSecurityConfig;

  @Bean
  public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {

    http.csrf().disable()
        .cors()

        .and()
        .sessionManagement()
        .sessionCreationPolicy(SessionCreationPolicy.STATELESS)
        .sessionAuthenticationStrategy(new NullAuthenticatedSessionStrategy())

        .and()
        .httpBasic().disable()
        .formLogin().disable()
        .oauth2ResourceServer().jwt();

    httpSecurityConfig.configure(http);

    return http.build();
  }
}

Class Diagram

Method Security

Testing

I have created this Spring Boot project that use this library available at https://github.com/czetsuya/ct-keycloak-spring-security. This project contains the Security configuration, custom method expression handler, and sample controllers.

  @GetMapping("/hello")
  @ResponseStatus(HttpStatus.OK)
  public String hello(@CurrentSecurityContext(expression = "authentication") Authentication auth) {

    log.debug("" + auth.getPrincipal());
    log.debug("" + auth.getCredentials());
    log.debug("" + auth.getDetails());

    return "Hello " + auth.getPrincipal();
  }

  @GetMapping("/api/testing/authenticated")
  @PreAuthorize("isAuthenticated()")
  @ResponseStatus(HttpStatus.OK)
  public String authenticated(@CurrentSecurityContext(expression = "authentication") Authentication auth) {

    log.debug("" + auth.getPrincipal());
    log.debug("" + auth.getCredentials());
    log.debug("" + auth.getDetails());

    return "Hello " + auth.getPrincipal();
  }

  @GetMapping("/api/testing/authorized")
  @PreAuthorize("isAuthorized()")
  @ResponseStatus(HttpStatus.OK)
  public String authorized() {
    return "authorized";
  }

  @GetMapping("/api/testing/unauthorized")
  @PreAuthorize("isUnAuthorized()")
  @ResponseStatus(HttpStatus.FORBIDDEN)
  public String unAuthorized() {
    return "unauthorized";
  }

Endpoints

• /hello - This endpoint is not secured, therefore it is available even without an authenticated token.
• /api/testing/authenticated - This endpoint needs an authenticated user.
• /api/testing/authorized - This endpoint needs an authenticated user and performs the validation in. CtAppMethodSecurityExpressionExtension.isAuthorized which return a hard-coded true. Thus, it should be accessible.
• /api/testing/unauthorized - This endpoint needs an authenticated user and performs the validation in CtAppMethodSecurityExpressionExtension.isUnAuthorized which return a hard-coded false. Thus, it should not be accessible.

You can add custom authorization rules in CtAppMethodSecurityExpressionExtension, and it will be automatically added to the Spring security context.

Postman

Get a Token

To get a token, create a new request in Postman and under the authorization tab, fill-up the "Configure New Token" tab.

Click the Get New Access Token and enter a valid credential.

Follow this guide: How to Generate Amazon Cognito Access Using Postman if you are not familiar with AWS Cognito.

And then you can copy and use the generated bearer-token to create new requests inside Postman.

Other Clients

• AWS Cognito