[TLS] Simple way to drop re-negotiation in HTTP (Re: draft-rescorla-tls-renegotiate.txt)

Nicolas Williams <Nicolas.Williams@sun.com> Sat, 07 November 2009 00:06 UTC

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Date: Fri, 6 Nov 2009 17:47:58 -0600
From: Nicolas Williams <Nicolas.Williams@sun.com>
To: Marsh Ray <marsh@extendedsubset.com>
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Subject: [TLS] Simple way to drop re-negotiation in HTTP (Re: draft-rescorla-tls-renegotiate.txt)
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On Fri, Nov 06, 2009 at 05:41:23PM -0600, Marsh Ray wrote:
> Michael D'Errico wrote:
> > 
> > A server can still negotiate an SSLv3 connection as it does today.
> > It just can't re-negotiate that connection later.
> 
> But on the server question:
> 
> There is a large, but unknown, group of sites that really depend on
> being able to serve different requirements for client certs from the
> same IP.

The simplest way to drop re-negotiation in web servers is this (based on
an idea by Nelson Bolyard):

 - start two instances of the web server, one on an alternate port
   number, with the same contents

 - the primary instance will accept TLS user authentication, but will
   not require it

 - the instance on the alternate port will always require TLS user
   authentication

 - neither instance accepts TLS re-negotiations

 - whenever the primary instance of the web server would request user
   authentication via TLS do this instead: re-direct to client to the
   same resource on the alternate port.

That's almost entirely automatic.  The only thing a webmaster must do is
pick a suitable port number for the instance that requires user
authentication.

The redirects will add some round-tripage.  They can be avoided somewhat
by re-writing URLs in contents served to point to the right server
instance.

Ugly, yes, but automatable.

Nico
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