Re: WGLC p1: MUST fix Content-Length?

Alex Rousskov <rousskov@measurement-factory.com> Wed, 01 May 2013 07:56 UTC

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Date: Wed, 01 May 2013 01:54:26 -0600
From: Alex Rousskov <rousskov@measurement-factory.com>
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Subject: Re: WGLC p1: MUST fix Content-Length?
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On 05/01/2013 01:43 AM, Willy Tarreau wrote:
> On Wed, May 01, 2013 at 01:37:29AM -0600, Alex Rousskov wrote:
>> On 05/01/2013 01:22 AM, Willy Tarreau wrote:
>>> On Tue, Apr 30, 2013 at 11:53:28PM -0600, Alex Rousskov wrote:
>>>> Hello,
>>>>
>>>>     When talking about a Content-Length header field with multiple
>>>> identical values, Part 1 Section 3.3.2 of HTTPbis says:
>>>>
>>>>> the recipient MUST either reject the message as invalid or
>>>>> replace the duplicated field-values with a single valid
>>>>> Content-Length field containing that decimal value prior to
>>>>> determining the message body length.
>>>>
>>>> It is not clear whether "recipient MUST replace" (a requirement on the
>>>> recipient) also implies that "a sender MUST replace [...] when
>>>> forwarding the message" (a requirement on the sender). This issue has
>>>> been raised on 2011/11/28, but the discussion diverged, and I could not
>>>> tell whether there was a consensus on what the correct interpretation is.
>>>>
>>>> Please decide whether a proxy MUST "fix" such Content-Length headers
>>>> when forwarding the message and adjust the above text to clarify one way
>>>> or another.
>>>
>>> That's what the discussion converged to. I even modified haproxy in order
>>> to do so. The idea is simple : if you receive a message with multiple
>>> content lengths, either you can't deal with them and must reject the
>>> message, or you can deal with them and then you know how to fix the
>>> message before interpreting it or forwarding it, so you must do so.
>>>
>>> Do you think the text needs to be adjusted ?
>>
>> Yes, of course. The current text is not clear IMO, as I tried to explain
>> in the beginning of this message.
> 
> Then what about :
> 
>    recipient MUST either reject the message as invalid or replace the
>    duplicated field-values with a single valid Content-Length field
>    containing that decimal value prior to determining the message body
> -  length.
> +  length or forwarding it.

That would work, IMO, although I would replace "it" with "the message".


Thank you,

Alex.