ngx_http_js_challenge_module: A C repository from Vik2009

ngx_http_js_challenge_module

Simple javascript proof-of-work based access for Nginx with virtually no overhead.

Easy installation: just add load_module /path/to/ngx_http_js_challenge_module.so; to your nginx.conf file and follow the configuration instructions.

Configuration

Simple configuration

server {
    js_challenge on;
    js_challenge_secret "change me!";

    # ...
}

Advanced configuration

server {
    js_challenge on;
    js_challenge_secret "change me!";
    js_challenge_html /path/to/body.html;
    js_challenge_bucket_duration 3600;
    js_challenge_title "Verifying your browser...";

    location /static {
        js_challenge off;
        alias /static_files/;
    }

    location /sensitive {
        js_challenge_bucket_duration 600;
        #...
    }

    #...
}

js_challenge on|off Toggle javascript challenges for this config block
js_challenge_secret "secret" Secret for generating the challenges. DEFAULT: "changeme"
js_challenge_html "/path/to/file.html" Path to html file to be inserted in the <body> tag of the interstitial page
js_challenge_title "title" Will be inserted in the <title> tag of the interstitial page. DEFAULT: "Verifying your browser..."
js_challenge_bucket_duration time Interval to prompt js challenge, in seconds. DEFAULT: 3600

Installation

Add load_module ngx_http_js_challenge_module.so; to /etc/nginx/nginx.conf
Reload nginx -s reload

Build from source

These steps have to be performed on machine with compatible configuration (same nginx, glibc, openssl version etc.)

Install dependencies

apt install libperl-dev libgeoip-dev libgd-dev libxslt1-dev libpcre3-dev

Download nginx tarball corresponding to your current version (Check with nginx -v)

wget https://nginx.org/download/nginx-1.16.1.tar.gz
tar -xzf nginx-1.16.1.tar.gz
export NGINX_PATH=$(pwd)/nginx-1.16.1/

Compile the module

git clone https://github.com/simon987/ngx_http_js_challenge_module
cd ngx_http_js_challenge_module
./build.sh

The dynamic module can be found at ${NGINX_PATH}/objs/ngx_http_js_challenge_module.so

Known limitations / TODO

Users with cookies disabled will be stuck in an infinite refresh loop (TODO: redirect with a known query param, if no cookie is specified but the query arg is set, display an error page)
If nginx is behind a reverse proxy/load balancer, the same challenge will be sent to different users and/or the response cookie will be invalidated when the user is re-routed to another server. (TODO: use the x-real-ip header when available)

Vik2009/ngx_http_js_challenge_module