NGINX FastCGI

Unlike other web servers, nginx(8) does not offer a built-in FastCGI implementation.

PHP-FPM

First install and configure PHP-FPM.

nginx(8) just needs to be configured to proxy requests.

location ~ \.php(/|$) {
    fastcgi_split_path_info ^(.+?\.php)(/.*)$;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    fastcgi_param PATH_INFO       $fastcgi_path_info;
    try_files $uri =404;

    fastcgi_pass localhost:9000;
    include fastcgi_params;
}

To use a Unix socket to pass requests, try fastcgi_pass localhost:9000;.

Hardening

A common tactic for hardening a FastCGI program is to run php-fpm(8) in a different working directory.

This can lead to issues with the try_files directive, which checks for the existence of a file before responding to a request. On success it overwrites the $uri variable with the local URI. This is a mitigation for embedded PHP attacks.

A workaround is to create empty files in the web root to satisfy try_files.

location ~ \.php(/|$) {
    fastcgi_split_path_info ^(.+?\.php)(/.*)$;
    fastcgi_param SCRIPT_FILENAME /path/to/php/working/directory/$fastcgi_script_name;
    fastcgi_param PATH_INFO       $fastcgi_path_info;
    try_files $uri =404;

    fastcgi_pass localhost:9000;
    include fastcgi_params;
}

Alternatively, replace try_files with a custom instruction.

location ~ \.php(/|$) {
    fastcgi_split_path_info ^(.+?\.php)(/.*)$;
    if (!-f $document_root$fastcgi_script_name) {
      return 404;
    }
}

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