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Re: delta encoding and state management

From: Willy Tarreau <w@1wt.eu>
Date: Tue, 22 Jan 2013 23:29:45 +0100
To: Roberto Peon <grmocg@gmail.com>
Cc: "William Chan (?????????)" <willchan@chromium.org>, James M Snell <jasnell@gmail.com>, Nico Williams <nico@cryptonector.com>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
Message-ID: <20130122222945.GN30692@1wt.eu>
On Tue, Jan 22, 2013 at 01:54:18PM -0800, Roberto Peon wrote:
> The thing that isn't in delta, etc. already is the idea of 'rooting' the
> path space with the single request (which I like, but... it is subject to
> the CRIME exploit if path-prefix grouping is done automatically by the
> browser (instead of being defined by the content-developer)).

I think that if the path-prefix only contains complete path components (not
just some chars), then we're fine with the CRIME attack because in order to
make the browser merge requests, the attacker has to brute-force each path
component's name. Also, as long as it remains a path, it doesn't unveil what
is located behind, which generally contains the most interesting stuff.

> IF we take your proposal for eliminating much of the common-path prefix and
> ensure that it isn't subject to CRIME, that is a winner in any scheme.

Let's face it, the CRIME attack is against optimizations for redundant
elements. We probably need to spend more time analysing all the failures
involved in the attack itself than refraining from optimizing redundancy.
I mean, how a forged request from an attacker slips in the middle of valid
requests and how we can prevent it from being merged, or at least have it
in its own group.

Received on Tuesday, 22 January 2013 22:30:17 UTC

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