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New SSL Features for Nginx

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As a Puppet Mongrel Nginx user, I’m really ashamed about the convoluted nginx configuration needed (two server blocks listening on different ports, you need to direct your clients CA interactions to the second port with –ca_port), and the lack of support of proper CRL verification.

If you are like me, then there is some hope in this blog post.

Last week-end, I did some intense Puppet hacking (certainly more news about this soon), and part of this work is two Nginx patch:

  • The first one adds support for ssl_client_verify optional. In this mode nginx accepts a client without a certificate, and of course accepts a client as long as it verifies against the CA certificate.
  • The second patch adds support for CRL PEM files (the one we usually deploy in Puppet).

Installation

First, download both patches:

Then apply them to Nginx (tested on 0.7.59):

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$ cd nginx-0.7.59
$ patch -p1 < ../0001-Support-ssl_client_verify-optional-and-ssl_client_v.patch
$ patch -p1 < ../0002-Add-SSL-CRL-verifications.patch

Then build Nginx as usual.

Usage

Here is a revised Puppet Nginx Mongrel configuration:

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upstream puppet-production {
  server 127.0.0.1:18140;
  server 127.0.0.1:18141;
}

server {
  listen 8140;

  ssl                     on;
  ssl_session_timeout     5m;
  ssl_certificate         /var/lib/puppet/ssl/certs/puppetmaster.pem;
  ssl_certificate_key     /var/lib/puppet/ssl/private_keys/puppetmaster.pem;
  ssl_client_certificate  /var/lib/puppet/ssl/ca/ca_crt.pem;
  ssl_ciphers             SSLv2:-LOW:-EXPORT:RC4+RSA;
  # allow authenticated and client without certs
  ssl_verify_client       optional;
  # obey to the Puppet CRL
  ssl_crl /var/lib/puppet/ssl/ca/ca_crl.pem;

  root                    /var/tmp;

  location / {
    proxy_pass              http://puppet-production;
    proxy_redirect         off;
    proxy_set_header    Host             $host;
    proxy_set_header    X-Real-IP        $remote_addr;
    proxy_set_header    X-Forwarded-For  $proxy_add_x_forwarded_for;
    proxy_set_header    X-Client-Verify  $ssl_client_verify;
    proxy_set_header    X-SSL-Subject    $ssl_client_s_dn;
    proxy_set_header    X-SSL-Issuer     $ssl_client_i_dn;
    proxy_read_timeout  65;
  }
}

Reload nginx, and enjoy :-)

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