Re: [secdir] secdir review of draft-ietf-httpbis-p4-conditional-19

Mark Nottingham <mnot@mnot.net> Fri, 06 July 2012 05:56 UTC

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From: Mark Nottingham <mnot@mnot.net>
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Date: Fri, 6 Jul 2012 15:56:46 +1000
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To: Klaas Wierenga <klaas@cisco.com>
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Cc: draft-ietf-httpbis-p4-conditional.all@tools.ietf.org, The IESG <iesg@ietf.org>, secdir@ietf.org
Subject: Re: [secdir] secdir review of draft-ietf-httpbis-p4-conditional-19
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Klass,

Thanks for your review and kind words, and apologies for the delay.

I've opened a new ticket for the security-related issues:
  http://trac.tools.ietf.org/wg/httpbis/trac/ticket/365

... and another for the editorial matters:
  http://trac.tools.ietf.org/wg/httpbis/trac/ticket/366

There are a few remaining below which I'll answer directly.

On 23/04/2012, at 11:51 PM, Klaas Wierenga wrote:

> - - 2.2.2 p7, comparision
> 
> Is it really neccessary to have the elaborate determination whether
> the vlaidator is weak or strong, with arbitrary time intervals etc.?
> It seems very error prone and confusing for implementers. Why not just
> say that Last-Modified is weak, and if you want strong use ETags.

If we were defining the protocol from scratch, I'd agree, but we need to stay consistent with how HTTP is already implemented, used and defined, and that can sometimes be messy / complex.


> - - 2.3 ETag, p9, Note
> 
> "ought to" is not very normative. Why not make it MUST or SHOULD?

We've used that terminology when we want to give implementation advice, but cannot impose a new RFC2119-level requirement, because it would make existing implementations non-conformant (as per our charter).


> 3.4 p17, If-Unmodified-Since
> 
> Why not defining the the result of a request having both an
> If-Unmodified-Since and a If-None-Match or If-Modified-Since?

This is already being discussed in:
  http://trac.tools.ietf.org/wg/httpbis/trac/ticket/241


> 4.1 p17, Not modified, second paragraph
> 
> A 304 response..... isn't this a fine case of a SHOULD rather than a
> MUST? Or perhaps "A 304 response MUST include a Date header field,
> unless the origin server.... , in that case a Date header field MUST
> NOT be provided", and what actually does "reasonable approximation" mean?

I'm not sure what you're concerned about here; it's a MUST requirement because it's important for interop.

--
Mark Nottingham   http://www.mnot.net/