Re: Response to HTTP2 expresions of interest

On Fri, Jul 13, 2012 at 11:21 AM, Poul-Henning Kamp <phk@phk.freebsd.dk>wrote:


> TLS communication today already have an envelope consisting of
> IP# + TCP port numbers, and unless your adversary is totally
> incompetent, he also has the DNS lookup that gave you that IP#.
>
> QED: Putting the "Host:" in the HTTP envelope does not leak any
> information your adversary doesn't already have or can guess.
>

That’s just not true.  There are lots of ways to get to a particular origin
server, and I would think that for a malicious person in the middle, the
Host header would be more interesting than the ostensible IP address.  On
the other hand, I do understand why a payload-oblivious load balancer would
need to see that header.  It is simply the case that we have two objectives
which are apparently in conflict. No, I don’t have a solution (or even a
strong opinion, yet, although I’m inclined to err on the side of protecting
user privacy at the expense of almost all else).  -Tim


>
> Even if we stopped here, it would be a major benefit over TLS
> in terms of enabling websites to roll out protection for their
> customers.
>
> To make it better, we need to add a session identifier, but today
> we pretend HTTP is stateless so we don't have one (so people
> hack it with cookies).
>
> Finally, to do what people do today we would need to include the
> URI, but that is by far the most troublesome of the three fields.
>
> I belive, but it should be seriously investigated, that if we add
> a session-concept to HTTP2, the envelope would just need to be Host:
> + session-nonce.
>
> In difference from TLS, that would allow us to mix protected and
> unprotected traffic on the same TCP connection, thus avoiding
> the extra TCP for protection upgrade, and making life much
> easier and efficient for proxies.
>
> It also means that you do not need to put your certificate on
> the HTTP router/load-balancer, but can put it on the specific
> webservers which host the protected stuff.
>
> SSL/TLS was a quick hack to protect HTTP, one of the far too
> many quick hacks in HTTP world.  We should try to eliminate
> them.
>
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk@FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
>