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Re: #288: Considering messages in isolation

From: Mark Nottingham <mnot@mnot.net>
Date: Thu, 30 Jun 2011 11:02:40 +1000
Cc: Julian Reschke <julian.reschke@gmx.de>, httpbis Group <ietf-http-wg@w3.org>
Message-Id: <362DDB27-65B6-48EE-9DB1-B5099F274F13@mnot.net>
To: Adrien de Croy <adrien@qbik.com>

On 30/06/2011, at 10:52 AM, Adrien de Croy wrote:

> 
> How does auth fit in with this, esp any challenge-response based authentication or connection-oriented auth.

I think it's well-established that "connection-oriented" authentication is fundamentally incompatible with HTTP, and shouldn't be attempted. Yes, NTLM does it, and that causes *significant* problems in all of the implementations I'm aware of.

> NTLM clearly requires an assumption that authentication state across multiple requests is associated with the connection the requests are received on.
> 
> Is Digest also a problem with this?

No.

> I realise there's not really anything an O-S can do, since a connection might have come from a proxy that aggregates clients into the same connection.
> 
> Does the "Proxy-Support: session-based-authentication" header mess with this, IOW do we have a collision here with RFC4559

That's Informational, although I'm a little surprised it was let through without a note to the effect that it breaks HTTP. Might be worth raising an errata to that effect.


> 
> Regards
> Adrien
> 
> 
> On 30/06/2011 12:01 a.m., Julian Reschke wrote:
>> On 2011-06-28 07:15, Mark Nottingham wrote:
>>> Milestone set for -15.
>>> ...
>> 
>> Applied with <http://trac.tools.ietf.org/wg/httpbis/trac/changeset/1317>.
>> 
>> I added it to the new section, which now reads:
>> 
>> 2.2.  Message Orientation and Buffering
>> 
>>   Fundamentally, HTTP is a message-based protocol.  Although message
>>   bodies can be chunked (Section 6.2.1) and implementations often make
>>   parts of a message available progressively, this is not required, and
>>   some widely-used implementations only make a message available when
>>   it is complete.  Furthermore, while most proxies will progressively
>>   stream messages, some amount of buffering will take place, and some
>>   proxies might buffer messages to perform transformations, check
>>   content or provide other services.
>> 
>>   Therefore, extensions to and uses of HTTP cannot rely on the
>>   availability of a partial message, or assume that messages will not
>>   be buffered.  There are strategies that can be used to test for
>>   buffering in a given connection, but it should be understood that
>>   behaviors can differ across connections, and between requests and
>>   responses.
>> 
>>   Recipients MUST consider every message in a connection in isolation;
>>   because HTTP is a stateless protocol, it cannot be assumed that two
>>   requests on the same connection are from the same client or share any
>>   other common attributes.
>> 
>> 
>> Best regards, Julian
>> 
> 
> -- 
> Adrien de Croy - WinGate Proxy Server - http://www.wingate.com
> WinGate 7 beta out now - http://www.wingate.com/getlatest/
> 

--
Mark Nottingham   http://www.mnot.net/
Received on Thursday, 30 June 2011 01:03:08 GMT

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