Keycloak secured Spring Boot Application CORS error when hitting endpoint using ReactJS application

Question

I have a ReactJS and Java Spring Boot applications, both secured by Keycloak 11.0.2.

Keycloak is on port 8083, ReactJS on 3000 and Spring App is on 8085. If I try to use the configuration provided below, I'm not able to hit my endpoint and I'm getting CORS error.

Firefox:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:8083/auth/realms/sorcerer_realm/protocol/openid-connect/auth?response_type=code&client_id=event_sorcerer&redirect_uri=http%3A%2F%2Flocalhost%3A8085%2Fsso%2Flogin&state=f52216b1-c235-4328-a2f9-d8448c3bf886&login=true&scope=openid. (Reason: CORS request did not succeed).

Chrome and Microsoft Edge:

Access to XMLHttpRequest at 'http://localhost:8083/auth/realms/sorcerer_realm/protocol/openid-connect/auth?response_type=code&client_id=event_sorcerer&redirect_uri=http%3A%2F%2Flocalhost%3A8085%2Fsso%2Flogin&state=f57ffa9f-9679-4476-aa03-af86c3abb3c2&login=true&scope=openid' (redirected from 'http://localhost:8085/api/worker/create/product') from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.


xhr.js:184 GET http://localhost:8083/auth/realms/sorcerer_realm/protocol/openid-connect/auth?response_type=code&client_id=event_sorcerer&redirect_uri=http%3A%2F%2Flocalhost%3A8085%2Fsso%2Flogin&state=f57ffa9f-9679-4476-aa03-af86c3abb3c2&login=true&scope=openid net::ERR_FAILED

When I try to hit my endpoint using Postman, I'm able to hit it. Below is my Keycloak Web Security configuration. The configuration uses application.properties file to configure Keycloak adapter. When I set .authorizeRequests().antMatchers("/**").permitAll() in the config, I'm also able to hit my endpoint from browser and Postman.

@KeycloakConfiguration
public class SecurityConfiguration extends KeycloakWebSecurityConfigurerAdapter {

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder authBuilder) throws Exception {
        final KeycloakAuthenticationProvider authProvider = keycloakAuthenticationProvider();
        
        authProvider.setGrantedAuthoritiesMapper(new SimpleAuthorityMapper());
        authBuilder.authenticationProvider(authProvider);
    }
    
    
    /**
     * Call superclass configure method and set the Keycloak configuration
     */
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        super.configure(http);
        
        http
            .csrf().disable()
            .cors()
            .and().sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS)
            .and().anonymous()
            //.and().authorizeRequests().antMatchers("/**").permitAll()         //Uncomment for requests to be allowed!
            .and().authorizeRequests().antMatchers("/api/admin/**").hasRole("ADMIN")
            .and().authorizeRequests().antMatchers("/api/manager/**").hasAnyRole("MANAGER")
            .and().authorizeRequests().antMatchers("/api/worker/**").hasRole("WORKER")
            .anyRequest().authenticated();
    }

    /**
     * Setup Auth Strategy. Don't add prefixes and suffixes to role strings
     */
    @Override
    protected SessionAuthenticationStrategy sessionAuthenticationStrategy() {
        return new RegisterSessionAuthenticationStrategy(new SessionRegistryImpl());
    }
    
    /**
     * Don't use keycloak.json. Instead, use application.yml properties.
     * @return
     */
    @Bean
    public KeycloakSpringBootConfigResolver KeycloakConfigResolver() {
        return new KeycloakSpringBootConfigResolver();
    }
}

Here is a part of application.properties that sets up Keycloak:

spring:
  jersey:
    type: filter


security: 
    oauth2: 
      resourceserver: 
        jwt: 
          issuer-uri: http://localhost:8083/auth/realms/sorcerer_realm/protocol/openid-connect/token
          jwk-set-uri: http://localhost:8083/auth/realms/sorcerer_realm/protocol/openid-connect/certs 


keycloak:
  realm: sorcerer_realm
  auth-server-url: http://localhost:8083/auth/
  ssl-required: external
  resource: event_sorcerer
  verify-token-audience: true
  credentials:
    secret-jwt:
      secret: d84611c9-af79-423b-b12c-bfa7fec23e85
  use-resource-role-mappings: true
  confidential-port: 0

Here is my ReactJS application's Keycloak adapter setup:

const keycloakConfig = {
    "clientId": "event_sorcerer_frontend",
    "realm": "sorcerer_realm",
    "auth-server-url": "http://localhost:8083/auth/",
    "url": "http://localhost:8083/auth",
    "ssl-required": "external",
    "resource": "event_sorcerer",
    "public-client": true,
    "verify-token-audience": true,
    "use-resource-role-mappings": true,
    "confidential-port": 0
};

const keycloak = new Keycloak(keycloakConfig);

const initKeycloak = (onSuccessCallback, onFailureCallback) => {
    let success = false;

    timeoutWrapper(() => {
        if(!success){
            onFailureCallback();
        }
    });

    keycloak.init({
        onLoad: 'check-sso',
        silentCheckSsoRedirectUri: window.location.origin + '/silent-check-sso.html',
        pkceMethod: 'S256',

    }).then((isAuthenticated) => {
        success = true;
        if(isAuthenticated) {
            onSuccessCallback();
        } else {
            login();
        }
    });
}

Here is how I send the request to server:

export const Request = {
    configureAxiosDefault: () => {
        axios.defaults.baseURL = axiosDefaultConfiguration.baseUrl;
    },

    create: (data, endpoint, callback, errorCallback, finalCallback) => {
        axios.post(serverEndpoint + endpoint, {
            data: data,
            headers: {
                Authorization: `Bearer ${UserService.getToken()}`
            }
        })
        .then(response => Utility.isEmpty(callback) ?  defaultCallback(response) : callback(response))
        .catch(response => Utility.isEmpty(errorCallback) ? defaultErrorCallback(response) : errorCallback(response))
        .finally(response => {
            if(!Utility.isEmpty(finalCallback)) {
                finalCallback(response);
            }
        });
    },
}

Here is my Keycloak configuration for frontend. Backend is the same, except the Access Type is confidential and the Root/Base url are different (not 3000 but 8085):

Here is my CORS configuration bean:

@Configuration
public class CORSConfiguration {
    /**
     * Setup CORS
     * @return
     */
    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration config = new CorsConfiguration();
        
        config.setAllowCredentials(true);
        config.setAllowedOrigins(Arrays.asList("http://localhost:3000"));
        config.setAllowedMethods(Arrays.asList(CorsConfiguration.ALL));
        config.setAllowedHeaders(Arrays.asList(CorsConfiguration.ALL));
        config.setAllowCredentials(true);
        source.registerCorsConfiguration("/**", config);
        
        return source;
    }
}

And lastly, here is my endpoint. URL resolves to api/worker/create/product

@RestController
@RequestMapping(ControllerEndpointsPrefix.WORKER + "/create")
public class CreationController {
    @Autowired
    private UserAgregate userAgregate;

    @PostMapping("/product")
    public boolean createProduct(@RequestBody CreateProductCommand command) {
        return true;
    }
}

Answer 1

I've managed to solve this. The problem wasn't on the server side, but on client side.

configureAxiosDefault: () => {
    axios.defaults.baseURL = axiosDefaultConfiguration.baseUrl;
    axios.defaults.headers.Authorization = `Bearer ${UserService.getToken()}`
},

create: (data, endpoint, callback, errorCallback, finalCallback) => {
        axios.post(serverEndpoint + endpoint, data)
        .then(response => Utility.isEmpty(callback) ?  defaultCallback(response) : callback(response))
        .catch(response => Utility.isEmpty(errorCallback) ? defaultErrorCallback(response) : errorCallback(response))
        .finally(response => {
            if(!Utility.isEmpty(finalCallback)) {
                finalCallback(response);
            }
        });
    },

Server was unable to process the token, because I was sending it as a JSON object property. These changes made everything work OK.

So, CORS wasn't an issue at all. The issue was that request didn't contain an Authorization header.

There are a lot of StackOverflow questions regarding KeyCloak, and some of them incomplete and cryptic. I encountered a good amount of errors, because of OpenJDK, JDK versions etc. If anyone needs explanations and solutions, working Spring Boot configuration is on my repository: https://github.com/milosrs/EventSorcererBackend