Re: Benjamin Kaduk's Discuss on draft-ietf-httpbis-header-structure-18: (with DISCUSS and COMMENT)

Benjamin Kaduk <kaduk@mit.edu> Wed, 20 May 2020 16:23 UTC

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Date: Wed, 20 May 2020 09:23:05 -0700
From: Benjamin Kaduk <kaduk@mit.edu>
To: Mark Nottingham <mnot@mnot.net>
Cc: The IESG <iesg@ietf.org>, draft-ietf-httpbis-header-structure@ietf.org, httpbis-chairs@ietf.org, HTTP Working Group <ietf-http-wg@w3.org>, Tommy Pauly <tpauly@apple.com>
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Subject: Re: Benjamin Kaduk's Discuss on draft-ietf-httpbis-header-structure-18: (with DISCUSS and COMMENT)
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On Wed, May 20, 2020 at 08:39:03AM -0700, Benjamin Kaduk wrote:
> 
> > >>> Section 6
> > >>> 
> > >>> It seems worth mentioning the handling for duplicated key names (e.g.,
> > >>> in parameters and dictionaries) w.r.t. overwrite or must-be-unique, and
> > >>> how there have been previous vulnerabilities relating to different
> > >>> implementations choosing "first one wins" vs. "last one wins".
> > >> 
> > >> That doesn't seem to apply to a correct implementation, only to headers that *aren't* structured fields.
> > > 
> > > It's still motivation for why we are making the choices we did and a
> > > benefit that structured headers have over the existing mechanisms.
> > 
> > Right, but that doesn't seem appropriate in Security Considerations; it's more Introduction / motivating material.
> > 
> > > Also, it seems to explicitly apply to parameter map keys (per the earlier
> > > discussion).
> > 
> > I've added a note to this effect in the Dictionary and Parameter parsing algorithms; see latest commit.

Hmm, the note says this discards duplicates after the first one, but the
procedures say to overwrite an existing value.  Shouldn't the note say
something else?

-Ben