Re: [Technical Errata Reported] RFC7230 (4667)

Amos Jeffries <squid3@treenet.co.nz> Fri, 15 April 2016 12:16 UTC

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From: Amos Jeffries <squid3@treenet.co.nz>
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Subject: Re: [Technical Errata Reported] RFC7230 (4667)
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On 15/04/2016 9:58 a.m., Alex Rousskov wrote:
> On 04/14/2016 12:20 PM, Roy T. Fielding wrote:
> 
>> The next was if there were any examples we knew of where space
>> was included there.  None.
> 
>> Apache httpd [allows] for space-padding
>> of the chunk-size in fixed buffers
> 
> Too bad nobody from the Apache team was present during that discussion :-).
> 
> As you said, Apache httpd essentially uses the old syntax (and violates
> the new syntax in two places!) to accommodate space-padding (at least):
> 
>   chunk-ext = 0*10<BWS> ";" *( OWS / VCHAR / )
> 
> I know Squid and several ICAP agents that use HTTP parsers do similar
> things.


Well, for the record. Squid used to just absorb anything at all before
the line terminator LF. It was only when we changed 4.x beta to a parser
with strict syntax validation and thus not accepting SP in these
locations that this came to light.


At least one server ("IBM_HTTP_Server") is sending SP characters to pad
out the chunk-size field to 4 octets.

We have several others mentioning chunk decoding issues being logged,
but not yet investigated closely to say if its the same server
implementation or other interoperability issues.


Note that the Eratta proposed syntax, including the extra suggestions
will still not successfully match what Squid is sighting. We would also
need to allow BWS / OWS / SP trailing the chunk-size value when no
chunk-ext is present.

Amos