OpenEMR with nginx and php-fpm

Introduction

The LAMP stack (Linux + Apache + MySQL + PHP) is very popular for powering OpenEMR. However is it possible to use Nginx?. OpenEMR may support Nginx, in fact, some OpenEMR sites are powered by Nginx as the reverse proxy with Apache. At least that is my understanding. A while back, after an update, my OpenEMR, FreeBSD/Apache/Mysql/PHP stack broke down. That is when I started looking for other solutions and came across Nginx and I liked it.

There are multiple ways to implement Nginx. However, this guide implements Nginx as the primary server instead of Apache. Please note that Apache and Nginx are not interchangeable. Hence this guide. For example, there is no directory-level configuration (.htaccess or IIS's Web.config files) in Nginx. All configuration must be done at the server level, and the server must be reloaded with each change.

Initially, this guide assumes you already have a working SSL enabled Nginx server with PHP7.2 and php-fpm is enabled and running. Later on, I may add sections on how to install the different components in a FreeBSD system, which is what I know. Hopefully, you already have a basic understanding of how to work with Nginx and how to debug it.

Please note that this document is a work in progress. There may be bugs in this setup. Use it at your own risk. Please post your questions at the forum, https://community.open-emr.org/ I will be notifed if you include @gutiersa in your topic, your questions will help others. Comments are also welcome, please be kind.

We set up OpenEMR with SSL right from the start. In order for OpenEMR to work with Nginx, you have to configure the backend php-cgi. The Nginx default installation comes with three options for implementation of the CGI module: 'fastcgi', 'scgi' and 'uwsgi'. The CGI module connects Nginx and the php-fpm (PHP Fast Program Manager). We use the FastCGI module. The "fastcgi_params" file can already be found in the default Nginx configuration directory, which in FreeBSD is located at /usr/local/etc/nginx/

This is my setup (FEMP)

openemr-5.0.1_3

FreeBSD 11.1 (includes openSSL 1.0.2k)

nginx -1.14.0

Mysql-5.7

PHP-7.2 (includes the php-fpm server)

Important information regarding Nginx search instructions, placement and whitespaces are important:

^~  stop when found
~  case sensitive
~* case insensitive

Configuration files

/usr/local/etc/nginx/nginx.conf:

worker_processes  auto;
error_log  /var/log/nginx/error.log;
events { 
    worker_connections  1024; 
}
# start the http block
http {
  include       mime.types;
  default_type  application/octet-stream;

  log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';
  access_log  /var/log/access.log  main;

  # don't send the nginx version number in error pages and Server header
  server_tokens off;

  # config to don't allow the browser to render the page inside an frame or iframe
  # and avoid clickjacking http://en.wikipedia.org/wiki/Clickjacking
  # if you need to allow [i]frames, you can use SAMEORIGIN or even set an uri with ALLOW-FROM uri
  # https://developer.mozilla.org/en-US/docs/HTTP/X-Frame-Options
  add_header X-Frame-Options SAMEORIGIN;

  # when serving user-supplied content, include a X-Content-Type-Options: nosniff header along with the Content-Type: header,
  # to disable content-type sniffing on some browsers.
  # https://www.owasp.org/index.php/List_of_useful_HTTP_headers
  add_header X-Content-Type-Options nosniff;

  # This header enables the Cross-site scripting (XSS) filter built into most recent web browsers.
  # It's usually enabled by default anyway, so the role of this header is to re-enable the filter for 
  # this particular website if it was disabled by the user.
  # https://www.owasp.org/index.php/List_of_useful_HTTP_headers
  add_header X-XSS-Protection "1; mode=block";

  # with Content Security Policy (CSP) enabled(and a browser that supports it(http://caniuse.com/#feat=contentsecuritypolicy),
  # you can tell the browser that it can only download content from the domains you explicitly allow
  # http://www.html5rocks.com/en/tutorials/security/content-security-policy/
  # https://www.owasp.org/index.php/Content_Security_Policy
  # I need to find out if we can increase security by disabling 'unsafe-inline' 'unsafe-eval' for openemr
  # more: http://www.html5rocks.com/en/tutorials/security/content-security-policy/#inline-code-considered-harmful
  #add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://ssl.google-analytics.com https://assets.zendesk.com https://connect.facebook.net; img-src 'self' https://ssl.google-analytics.com https://s-static.ak.facebook.com https://assets.zendesk.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com https://assets.zendesk.com; font-src 'self' https://themes.googleusercontent.com; frame-src https://assets.zendesk.com https://www.facebook.com https://s-static.ak.facebook.com https://tautt.zendesk.com; object-src 'none'";

  sendfile        on;
  #tcp_nopush     on;

  #keepalive_timeout  0;
  server_names_hash_bucket_size 128;
  keepalive_timeout  65;

  gzip  off;
  upstream php { 
      server unix:/var/run/php-fpm.sock; 
  }
  index  index.html index.htm index.php;

  #  http host
  #  redirect all http traffic to https
  server {
      listen 80 default_server;
      listen [::]:80 default_server;
      server_name  example.net www.example.net;
      
      # Redirect all HTTP requests to HTTPS with a 301 Moved Permanently response.
      return 301 https://$host$request_uri;
  }

  #   openemr https host
  #   This is an ssl only openemr site
  server {
      listen 	 443 default_server ssl http2;
      listen  [::]:443 default_server ssl http2;
      server_name  example.net www.example.net;
      root /usr/local/nginx/www;

      ## redirect www to nowww
      if ($host = 'www.example.net' ) { 
		rewrite  ^/(.*)$  https://example.net/$1  permanent; 
      }   

      access_log /var/log/*/example.net_access_log main;
      error_log    /var/log/*/example.net_error_log notice;

      # openemr specific SSL settings
      # to customize your configuration: https://mozilla.github.io/server-side-tls/ssl-config-generator/
      # configuration can be placed here, or in a separate file named openemr-ssl.conf
      include openemr-ssl.conf;  

      ssl_certificate      /path/to/ssl.cert;
      ssl_certificate_key    /path/to/ssl.key;

      # restrict/protect certain files
      include globals.conf;   

      # deny access to writable files/directories
      location ~* ^/sites/*/(documents|edi|era) { 
		deny all;
                return 404; 
      }

      # deny access to certain directories
      location ~ ^/(contrib|Tests) { 
		deny all;
                return 404;
      }
	
      # Pick one of the following two blocks, but not both:
      # protect special files from outside openemer login, and restrict them to superAdmins only
      #location ~* ^/(admin|setup|acl_setup|acl_upgrade|sl_convert|sql_upgrade|gacl/setup|ippf_upgrade|sql_patch)\.php {
	#	auth_basic 				"Restricted Access"; 
	#	auth_basic_user_file 	/path/to/.htpasswd;
	#	fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; 
	#	fastcgi_pass php; 
	#	include fastcgi_params; 
      #}
      # If you pick this block, be sure to comment the previous one
      # Alternatively all access to these files can be denied
      #location ~* ^/(admin|setup|acl_setup|acl_upgrade|sl_convert|sql_upgrade|gacl/setup|ippf_upgrade|sql_patch)\.php { 
      #	deny all; 
      #	return 404; 
      #}

      location / {
		# try as file ($uri), as directory ($uri/) if not found, send to index file
		# no php is touched for static content
        	try_files $uri $uri/ /index.php;
      }	
	
      # redirect server error pages to the static page /50x.html
      error_page   500 502 503 504  /50x.html;
      location = /50x.html { 
		root   /usr/local/www/nginx-dist; 
      } 
    
      # pass the PHP scripts to the FastCGI server listening on unix socket, in this case php-fpm
      location ~* \.php$ {
		try_files $uri =404;
        	fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        	fastcgi_index index.php;
    	        fastcgi_pass php;
                include fastcgi_params; 
      }
      # dynamic stuff goes to php-proxy
      include php-proxy.conf;
    }
} # end http block

/usr/local/etc/nginx/globals.conf file:

# globals.conf configuration file.
# Designed to be included in any server {} block
# If this server only hosts openemr, this file can be merged with openemr.conf

# Stops the annoying error messages in the logs. robots are not allowed
location = /favicon.ico { 
      log_not_found off; 
      access_log off; 
}

location = /robots.txt  { 
      log_not_found off; 
      access_log off; 
}

# Deny all attempts to access hidden files such as .htaccess, .htpasswd, .DS_Store (Mac).
# Keep logging the requests to parse later (or to pass to firewall utilities such as fail2ban)
location ~ /\. {
      deny all; 
}

# protect or deny access to important server information and testing files
# alternatively, you can deny access to all files using {deny all; return 404;} or remove them
location ~* /(info|test)\.php$ {
	auth_basic "Restricted Access";
	auth_basic_user_file /path/to/.htpasswd;
	fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; 
	fastcgi_pass php; 
	include fastcgi_params; 
}

# Not sure if openemr needs this. it comes from wordpress
location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ { 
	access_log off; 
	log_not_found off; 
	expires max;
}

## Deny certain Referers
if ( $http_referer ~* (babes|forsale|girl|jewelry|love|nudit|organic|poker|porn|sex|teen) ) {
         #return 404;
         return 403;
}
     
# Stop deep linking or hot linking
location /images/ {
  valid_referers none blocked www.example.com example.com;
  if ($invalid_referer) {
       return   403;
   }
}

/usr/local/etc/nginx/php-proxy.conf:

# php proxy block
# should have "cgi.fix_pathinfo = 0;" in php.ini
#
location ~ \.php$ {
    # php-fpm must be in same machine. Otherwise there is risk of hacking
    try_files $uri =404;
    fastcgi_index  index.php;
    fastcgi_pass unix:/var/run/php-fpm.sock;
    fastcgi_buffer_size 16k;
    fastcgi_buffers 4 16k;
    fastcgi_param SCRIPT_FILENAME $request_filename;
    include fastcgi_params;
    fastcgi_intercept_errors on;
    fastcgi_read_timeout 120;
}

/usr/local/etc/nginx/openemr-ssl.conf:

Please note that this configuration is intended to provide tight protection to your openemr site. This will not work with older version browsers. For best results, start here: https://mozilla.github.io/server-side-tls/ssl-config-generator/ to generate your own custom configuration.

# openemr gets its own SSL configuration. It should be stricter than a regular ssl.conf
# SSL, go here to test your server: https://www.ssllabs.com/ssltest/
# For more information: https://wiki.mozilla.org/Security/Server_Side_TLS and 
# https://gist.github.com/plentz/6737338

# enable session resumption to improve https performance
# http://vincent.bernat.im/en/blog/2011-ssl-session-reuse-rfc5077.html
ssl_session_timeout 1d;
ssl_session_cache shared:SSL:50m;
ssl_session_tickets off;

# disable SSLv3, (enabled by default since nginx 0.8.19) 
#  also disable TLSv1 TLSv1.1, however this requires more modern browsers.
ssl_protocols TLSv1.2;
# ciphers chosen for forward secrecy and compatibility
# http://blog.ivanristic.com/2013/08/configuring-apache-nginx-and-openssl-for-forward-secrecy.html
ssl_ciphers 'ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256';
# enables server-side protection from BEAST attacks
# http://blog.ivanristic.com/2013/09/is-beast-still-a-threat.html
ssl_prefer_server_ciphers on;

# HSTS (ngx_http_headers_module is required) (15768000 seconds = 6 months)
add_header Strict-Transport-Security max-age=15768000;

# Notify the client that this domain, and its subdomains, must only be accessed using HTTPS (SSL or TLS), 
# and have it cache this information for the max-age period: typically 31,536,000 seconds, equal to about 1 year
# For more information: https://www.nginx.com/blog/http-strict-transport-security-hsts-and-nginx/
# Google maintains a “HSTS preload list” of web domains and subdomains that use HSTS and have submitted their names to https://hstspreload.appspot.com/. 
# This domain list is distributed and hardcoded into major web browsers. Clients that access web domains in this list automatically use HTTPS and refuse to access the site using HTTP.
# Be aware that once you set the STS header or submit your domains to the HSTS preload list, it is impossible to remove it. 
# It’s a one‑way decision to make your domains available over HTTPS only.
# "always" at end of statement requires nginx 1.7 or later
add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;

# # Diffie-Hellman parameter for DHE ciphersuites, recommended 2048 bits
# https://raymii.org/s/tutorials/Strong_SSL_Security_On_nginx.html for more information
# to generate your dhparam.pem file, run in the terminal: openssl dhparam -out /path/to/dhparam.pem 2048
ssl_dhparam /path/to/dhparam.pem;

# enable ocsp stapling (mechanism by which a site can convey certificate revocation information to visitors in a privacy-preserving, scalable manner)
# http://blog.mozilla.org/security/2013/07/29/ocsp-stapling-in-firefox/
#  https://raymii.org/s/tutorials/OCSP_Stapling_on_nginx.html
# fetch OCSP records from URL in ssl_certificate and cache them
ssl_stapling on;
ssl_stapling_verify on;

## verify chain of trust of OCSP response using Root CA and Intermediate certs
ssl_trusted_certificate /path/to/root_CA_cert_plus_intermediates;

# RESOLVERS
#resolver 	$DNS-IP-1 	$DNS-IP-2 	valid=300s;
# uncomment this line if localhost is running BIND
#resolver 	127.0.0.1 	[::1]:5353 	valid=300s;
# google resolvers
resolver	8.8.8.8	8.8.4.4	[2001:4860:4860::8888]  [2001:4860:4860::8844]	valid=300s;
resolver_timeout 5s;

Tools

Generate a conf file for multiple webservers including Nginx and Apache at: https://mozilla.github.io/server-side-tls/ssl-config-generator/

Check your ssl configuration: https://www.ssllabs.com/ssltest/

Geek Flare tools: https://tools.geekflare.com/tools

Cloudpiercer scanning tool to check if your IP is exposed: https://cloudpiercer.org

HPKP or HTTP Public Key Pinning: https://developer.mozilla.org/en-US/docs/Web/HTTP/Public_Key_Pinning

Content Security Policy (CSP): Find out which browsers support it. http://caniuse.com/#feat=contentsecuritypolicy

Google maintains a “HSTS preload list” of web domains and subdomains that use HSTS. To submit your domain got to, https://hstspreload.appspot.com/ This will cause your domain to only be accessible via https. Be careful, this is not reversible. Your site will no longer be accessible via http.

https://caniuse.com/

Check your Security Headers

References

Nginx official site

Setting up HTTPS in Nginx

FreeBSD official site

FreeBSD applications/ports, Freshports

PHP-FPM official site

Tutorial for installing free Let's Encrypt certificates in FreeBSD with Nginx.

Fjordvald, Martin Bjerretoft, and Clement Nedelcu. Nginx HTTP Server Harness the Power of Nginx to Make the Most of Your Infrastructure and Serve Pages Faster than Ever Before. Packt Publishing, 2018.

Security

SSL/TLS:

Mozilla's Security/Server Side TLS

SSL Labs' SSL and TLS Deployment Best Practices

SSL and Nginx:

Strong SSL Security on Nginx

Useful ssl configuration information ssl.conf file

I found this article very useful Guide to nginx ssl spdy hsts

Avoid clickjacking Wikipedia's Clickjacking page

Content Security Policy, CSP:

Open Web Application Security Project page on CSP

html5rocks CSP tutorial

SSL session reuse

Configuring Apache Nginx and Openssl for Forward secrecy

X Frames Options

Open Web Application Security Project List of useful HTTP headers

HSTS and Nginx

OCSP Stapling:

OCSP Stapling on Nginx

OCSP Stapling in Firefox

Exploits:

Is Beast still a threat?