Opened 2 years ago

Closed 2 years ago

#1414 closed defect (invalid)

ACLs have no effect for root location with `return 301 ...` or `rewrite ... permanent`

Reported by: tiandrey@… Owned by:
Priority: minor Milestone:
Component: nginx-module Version: 1.12.x
Keywords: access rewrite Cc:
uname -a: Linux someserver 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19) x86_64 GNU/Linux
nginx -V: nginx version: nginx/1.12.1
built by gcc 4.9.2 (Debian 4.9.2-10)
built with OpenSSL 1.0.2j 26 Sep 2016
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/run/nginx.pid --lock-path=/run/lock/nginx.lock --http-client-body-temp-path=/run/shm/body_temp --http-proxy-temp-path=/run/shm/proxy_temp --http-fastcgi-temp-path=/run/shm/fastcgi_temp --http-uwsgi-temp-path=/run/shm/uwsgi_temp --http-scgi-temp-path=/run/shm/scgi_temp --with-http_ssl_module --with-http_realip_module --with-http_sub_module --with-http_dav_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_stub_status_module --with-mail --with-http_v2_module --with-http_geoip_module --with-select_module --with-http_auth_request_module --with-poll_module --with-debug

Description

I had to configure new server entry for simply redirecting clients with IPs from whitelist to another URL, and the rest of clients should have seen 403 Forbidden answer. Obvious configuration:

server {
  listen 80;
  server_name someserver.ru;
  allow 10.0.0.0/8;
  deny all;
  location {
    return 301 http://anotherurl.com;
  }
}

However, nginx with this configuration was returning 301 to all clients, even those not in allowed list.
Tried using rewrite ^/.*$ http://anotherurl.com permanent; instead of return 301 - same results.
Tried moving allow/deny into location / {}, moving return/rewrite outside location / {} (e.g. into server context) - same results.
The only thing that changed this behavior was removing allow line, leaving deny all - after that server began answering 403 to all requests.

Finally I came to the following workaround:

server {
    listen 127.0.5.6:321;
    return 301 http://anotherurl.com;
}

server {
  listen 80;
  server_name someserver.ru;

  allow 10.0.0.0/8;
  deny all;

  location / {
    proxy_pass http://127.0.5.6:321;
  }
}

But that looks crutchy, doesn't it?

There are no exceptions described in documentation, so I guess this behavior of nginx is wrong and should be fixed to respect ACLs.

Change History (1)

comment:1 by Maxim Dounin, 2 years ago

Resolution: invalid
Status: newclosed

The rewrite module directives are used to conditionally select appropriate configurations, see docs. As such, they are executed before any other module checks, including allow/deny and auth_basic.

Removing allow line won't help either - if it does in your case, you probably missed something.

If you want to do checks before given rewrite directives, you can do so by using if (which is a rewrite module directive, and hence are executed sequentially as specified in the configuration). Something like this should work:

geo $blocked {
    default 1;
    10.0.0.0/8 0;
}

server {
    listen 80;
    server_name example.com;

    if ($blocked) {
        return 403;
    }

    return 301 http://secret.example.com/;
}
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