Nginx Reverse Proxy Websocket Authentication - HTTP 403

Question

I'm using Nginx as a reverse proxy of a Spring boot application. I also use Websockets with sockjs and stomp messages.

Here is the context configuration.

<websocket:message-broker application-destination-prefix="/app">
 <websocket:stomp-endpoint path="/localization" >
 <websocket:sockjs/>
 </websocket:stomp-endpoint>
 <websocket:simple-broker prefix="/topic" />
</websocket:message-broker>

Here is the client code:

var socket = new SockJS(entryPointUrl);
var stompClient = Stomp.over(socket);
var _this = this;
stompClient.connect({}, function () {
 stompClient.subscribe('/app/some-url', function (message) {
 // do some stuff
 });
});

I also you Spring Security to protect some content.

@Configuration
@Order(4)
public static class FrontendSecurityConfig extends WebSecurityConfigurerAdapter {
 @Override
 protected void configure(HttpSecurity http) throws Exception {
 http.authorizeRequests()
 .antMatchers("/js/**", "/css/**", "/webjars/**").permitAll()
 .anyRequest().authenticated()
 .and()
 .formLogin().loginPage("/login").permitAll()
 .and()
 .logout().permitAll();
 }
}

Everything works great, expect when I run this application behind a Nginx reverse proxy. Here is the reverse configuration:

 proxy_pass http://testsysten:8080;
 proxy_set_header X-Real-IP $remote_addr;
 proxy_set_header Host $host;
 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
 # WebSocket support (nginx 1.4)
 proxy_http_version 1.1;
 proxy_set_header Upgrade $http_upgrade;
 proxy_set_header Connection $http_connection;
 # Max body size
 client_max_body_size 10M;

The connection always fails with a HTTP 403 code.

I'm using version 1.9.7.

Do you have any idea, why the client does not gets authenticated?

I know similar questions, like this one but the solutions do not work at all.

Update

I managed to run the application over HTTP. I need to pass the CSRF token in the Nginx configuration. New configuration is:

 proxy_pass http://testsysten:8080;
 proxy_set_header X-Real-IP $remote_addr;
 proxy_set_header Host $host;
 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
 # Pass the csrf token (see https://de.wikipedia.org/wiki/Cross-Site-Request-Forgery)
 # Default in Spring Boot
 proxy_pass_header X-XSRF-TOKEN;
 # WebSocket support (nginx 1.4)
 proxy_http_version 1.1;

Only missing is redirect over HTTPS. In the Spring logs is see following entry:

o.s.w.s.s.t.h.DefaultSockJsService - Processing transport request: GET http://testsystem:80/localization/226/3mbmu212/websocket

Seems like Nginx Proxy needs to rewrite the to the right port.

Answer 1

I solved the problem by myself. Basically, Nginx needs to pass some additional header values if you want to use Websocket and Spring Security. The following lines need to be added to location section in your Nginx config:

 # Pass the csrf token (see https://de.wikipedia.org/wiki/Cross-Site-Request-Forgery)
 # Default in Spring Boot and required. Without it nginx suppresses the value
 proxy_pass_header X-XSRF-TOKEN;
 # Set origin to the real instance, otherwise a of Spring security check will fail
 # Same value as defined in proxy_pass
 proxy_set_header Origin "http://testsysten:8080"; 

• Shinebayar G: Thanks for the find! This also works in general if someone is doing proxy_pass to different hostname + websocket. Without these proxy_pass works but websocket always uses server_name hostname which breaks websocket.

Answer 2

The accepted solution did not work for me although I was using a very classical HTTPS configuration:

server {
 listen 443 ssl;
 location /ws {
 proxy_http_version 1.1;
 proxy_set_header Upgrade $http_upgrade;
 proxy_set_header Connection "upgrade";
 proxy_set_header Host $http_host;
 proxy_pass http://127.0.0.1:8888;
 }
...

The problem is that Spring checks the origin and specifically that code was causing me trouble:

// in org.springframework.web.util.UriComponentsBuilder.adaptFromForwardedHeaders(HttpHeaders):
 if ((this.scheme.equals("http") && "80".equals(this.port)) ||
 (this.scheme.equals("https") && "443".equals(this.port))) {
 this.port = null;
 }

In that code the scheme is 'http' and the port is 8888, which is not discarded because it is not the standard port.

The browser however hits https://myserver/ and the 443 port is omitted because it is the default HTTPS one.

Therefore the ports do not match (empty != 8888) and origin check fails.

Either you can disable origin checks in Spring WebSockets:

registry.addHandler( resgisterHandler(), "/ws" ).setAllowedOrigins( "*" );

or (probably safer) you can add the scheme and port to the NGINX proxy configuration:

 proxy_set_header X-Forwarded-Proto $scheme;
 proxy_set_header X-Forwarded-Port $server_port;

If you are interested, those headers are read in

org.springframework.web.util.UriComponentsBuilder.adaptFromForwardedHeaders(HttpHeaders)

For Spring Boot 2.2.2+

Starting with Spring Boot version 2.2.2 you should be adding following setting for these X-Forwarded-* headers to be taken into account:

server.forward-headers-strategy=native

(in application.properties for instance)

Answer 3

I had faced a similar problem. I was unable to use the basic Spring Security authentication with NGINX. Apart from setting the proxy_pass_header X-XSRF-TOKEN;, I also had to set underscores_in_headers on;, since NGINX by default does not allow headers with underscores and the CSRF token is named _csrf.

So my final configuration file looked like this:

server {
 underscores_in_headers on;
 listen 80 default_server;
 listen [::]:80 default_server ipv6only=on;
 root /usr/share/nginx/html;
 index index.html index.htm;
 # Make site accessible from http://localhost/
 server_name localhost;
 location / {
 # First attempt to serve request as file, then
 # as directory, then fall back to displaying a 404.
 try_files $uri $uri/ =404;
 # Uncomment to enable naxsi on this location
 # include /etc/nginx/naxsi.rules
 }
 location /example/ {
 proxy_pass_header X-XSRF-TOKEN;
 proxy_pass http://localhost:8080/;
 }
}

Answer 4

I solved this problem without CSRF header in NGINX proxy.

My stack: spring-boot, spring-security (with redis session store), spring-boot-websocket with default STOMP implementation, NGINX to serve frontend and proxied to another services that frontend consume.

In first time I use the default configuration show in the NGINX Blog here and here (copy and paste for history):

http {
 map $http_upgrade $connection_upgrade {
 default upgrade;
 '' close;
 }
 upstream websocket {
 server 192.168.100.10:8010;
 }
 server {
 listen 8020;
 location / {
 proxy_pass http://websocket;
 proxy_http_version 1.1;
 proxy_set_header Upgrade $http_upgrade;
 proxy_set_header Connection $connection_upgrade;
 }
 }
}

But dont work, still 403 Forbidden.

I fixed this issue with the configuration below (the real important part to fix websocket is # WebSocket Proxy):

worker_processes 1;
events {
 worker_connections 1024;
}
http {
 include mime.types;
 default_type application/octet-stream;
 sendfile on;
 keepalive_timeout 65;
 server {
 listen 30010;
 server_name localhost;
 client_max_body_size 10M;
 location / {
 root /usr/share/nginx/html;
 index index.html index.htm;
 }
 # Backend API Proxy
 location /api {
 proxy_pass http://192.168.0.100:30080;
 proxy_set_header Host $http_host;
 proxy_set_header Access-Control-Allow-Origin 192.168.0.100;
 proxy_set_header X-Real-IP $remote_addr;
 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
 proxy_set_header X-NginX-Proxy true;
 rewrite ^/api/?(.*) /1ドル break;
 proxy_redirect off;
 }
 # CDN Proxy
 location ~ ^/cdn/(.*) {
 proxy_pass http://192.168.0.110:9000;
 rewrite ^/cdn/(.*) /1ドル break;
 }
 # This is the configuration that fix the problem with WebSocket
 # WebSocket Proxy
 location /ws {
 proxy_pass http://192.168.0.120:30090;
 proxy_http_version 1.1;
 proxy_set_header Upgrade $http_upgrade;
 proxy_set_header Connection "upgrade";
 proxy_set_header Host $http_host;
 proxy_set_header Access-Control-Allow-Origin 192.168.0.120;
 proxy_set_header X-Real-IP $remote_addr;
 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
 proxy_set_header X-NginX-Proxy true;
 }
 }
}

Answer 5

In my case (Spring Boot app), in addition to setting the Origin header as specified in the accepted answer, I had to set the Host header to match the ip:port of the Origin header, or to get rid of it altogether.

This is my working vhost config:

server {
 listen 443 ssl;
 listen [::]:443 ssl;
 ssl_certificate /etc/ssl/certs/<your-cert-file>.pem;
 ssl_certificate_key /etc/ssl/private/<your-key-file>.key;
 server_name <your-server-fqdn>;
 access_log /var/log/nginx/<your-server-fqdn>.access.log;
 error_log /var/log/nginx/<your-server-fqdn>.error.log error;
 root /srv/www/<your-server-fqdn>;
 index index.html index.html;
 location / {
 try_files $uri $uri/ /index.html;
 }
 location /api {
 proxy_pass http://127.0.0.1:8080/v1;
 }
 location /async-api {
 proxy_pass http://127.0.0.1:8080/stomp;
 proxy_http_version 1.1;
 # either set Host header as follows or get rid of the directive altogether 
 #proxy_set_header Host "127.0.0.1:8080";
 proxy_set_header Upgrade $http_upgrade;
 proxy_set_header Connection "Upgrade";
 # Set origin to the real instance, otherwise a of Spring security check will fail
 # Same value as defined in proxy_pass
 proxy_set_header Origin "http://127.0.0.1:8080";
 proxy_set_header X-Forwarded-Host $host:$server_port;
 proxy_set_header X-Forwarded-Server $host;
 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
 }
 location /admin-api {
 proxy_pass http://127.0.0.1:8080/api;
 }
}