Cross-Origin Resource Sharing with Spring Security

Question

I\'m trying to make CORS play nicely with Spring Security but it\'s not complying. I made the changes described in this article and changing this line in applicationCo

Answer 1

Since Spring Security 4.1, this is the proper way to make Spring Security support CORS (also needed in Spring Boot 1.4/1.5):

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedMethods("HEAD", "GET", "PUT", "POST", "DELETE", "PATCH");
    }
}

and:

@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(HttpSecurity http) throws Exception {
//        http.csrf().disable();
        http.cors();
    }

    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        final CorsConfiguration configuration = new CorsConfiguration();
        configuration.setAllowedOrigins(ImmutableList.of("*"));
        configuration.setAllowedMethods(ImmutableList.of("HEAD",
                "GET", "POST", "PUT", "DELETE", "PATCH"));
        // setAllowCredentials(true) is important, otherwise:
        // The value of the 'Access-Control-Allow-Origin' header in the response must not be the wildcard '*' when the request's credentials mode is 'include'.
        configuration.setAllowCredentials(true);
        // setAllowedHeaders is important! Without it, OPTIONS preflight request
        // will fail with 403 Invalid CORS request
        configuration.setAllowedHeaders(ImmutableList.of("Authorization", "Cache-Control", "Content-Type"));
        final UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", configuration);
        return source;
    }
}

Do not do any of below, which are the wrong way to attempt solving the problem:

• http.authorizeRequests().antMatchers(HttpMethod.OPTIONS, "/**").permitAll();
• web.ignoring().antMatchers(HttpMethod.OPTIONS);

Reference: http://docs.spring.io/spring-security/site/docs/4.2.x/reference/html/cors.html

Answer 2

I totally agree with the answer given by Bludream, but I have some remarks:

I would extend the if clause in the CORS filter with a NULL check on the origin header:

public class CorsFilter extends OncePerRequestFilter {

    private static final String ORIGIN = "Origin";


    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
        throws ServletException, IOException {

        if (request.getHeader(ORIGIN) == null || request.getHeader(ORIGIN).equals("null")) {
            response.addHeader("Access-Control-Allow-Origin", "*");
            response.setHeader("Access-Control-Allow-Credentials", "true");
            response.addHeader("Access-Control-Max-Age", "10");

            String reqHead = request.getHeader("Access-Control-Request-Headers");

            if (!StringUtils.isEmpty(reqHead)) {
                response.addHeader("Access-Control-Allow-Headers", reqHead);
            }
        }
        if (request.getMethod().equals("OPTIONS")) {
            try {
                response.getWriter().print("OK");
                response.getWriter().flush();
            } catch (IOException e) {
            e.printStackTrace();
            }
        } else{
            filterChain.doFilter(request, response);
        }
    }
 }

Furthermore, I noticed the following unwanted behavior: If I try to access a REST API with an unauthorized role, Spring security returns me an HTTP status 403: FORBIDDEN and the CORS headers are returned. However, if I use an unknown token, or a token that isn't valid anymore, an HTTP status 401: UNAUTHORIZED is returned WITHOUT CORS headers.

I managed to make it work by changing the filter configuration in the security XML like this:

<security:http use-expressions="true" .... >
    ...
    //your other configs
    <sec:custom-filter ref="corsFilter" before="HEADERS_FILTER"/>
</security:http>

And the following bean for our custom filter:

<bean id="corsFilter" class="<<location of the CORS filter class>>" />