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Re: Bad browser behaviour?

From: Willy Tarreau <w@1wt.eu>
Date: Tue, 20 Mar 2012 20:16:32 +0100
To: Eric Lawrence <ericlaw@exchange.microsoft.com>
Cc: Robert Brewer <fumanchu@aminus.org>, Adrien de Croy <adrien@qbik.com>, Adam Barth <w3c@adambarth.com>, HTTP Working Group <ietf-http-wg@w3.org>
Message-ID: <20120320191632.GB4074@1wt.eu>
Hi,

On Tue, Mar 20, 2012 at 05:22:15PM +0000, Eric Lawrence wrote:
> Most browsers don't warn on Content-Length underruns, and Chunked Encoding
> typically has the same behavior.
> 
> We have seen some real-world scenarios where a server using Chunked never
> sends the trailing 0CRLFCRLF and simply closes the connection. There are two
> scenarios of interest when considering the premature closure-- 1> where the
> last block was of the promised size (e.g. server promised n bytes and sent n)
> and 2> where the last block was shorter than the promised size when the
> connection was closed. The latter is obviously somewhat more "suspicious"
> than the former.

Indeed, I was wondering how the client would react if before closing, the
AV gateway would advertise a large chunk and then close. Alternatively, if
the client supports Trailers, it would be possible to emit only garbage to
fill the last chunk or the content-length and then emit a trailer indicating
that the content has failed validation. But for this, clients have to be
adapted.

Willy
Received on Tuesday, 20 March 2012 19:17:12 GMT

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