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From: Patrik Fältström <paf@cisco.com>
Date: Wed, 21 Nov 2001 10:09:05 +0100
To: John C Klensin <klensin@jck.com>, Martin Duerst <duerst@w3.org>, discuss@apps.ietf.org
Message-ID: <7174825.1006337345@localhost>
(a) I think it is a good thing to have a URI scheme defined for all
protocols we have in the IETF
(b) A specification of a URI scheme need to explain when it is to, and more
importantly, when it is not to be used

Correct me if I am wrong John, but the conclusion I see of this discussion
is that the document is describing the general URI, but, doesn't describe
enough in the Security Consideration Section why this is a bad thing to use
the wrong way.


--On 01-11-21 03.45 -0500 John C Klensin <klensin@jck.com> wrote:

> --On Wednesday, 21 November, 2001 16:37 +0900 Martin Duerst
> <duerst@w3.org> wrote:
>> I don't have much to add here, except to very clearly point
>> out that URIs are about much more than only 'just click here'.
> Of course.  But we have claimed for years that the default
> answer to a request for a new URL/URI type is, in the absence of
> justification, "no" .  And the only justifications that are
> apparent for this one are "just click here" and, more
> importantly, "make it a bit more convenient to specify what goes
> into a configuration file".   I don't consider either, in
> itself, to be adequate.
> Moreover, in most configuration file contexts with TFTP (or
> anything else for that matter), one of the following is true:
> (i) The config file entry is going to be a TFTP reference and
> anything else is invalid.  In that case, use of a URI provides
> not extra advantages other than appearing to be "modern"
> (another reason I don't find persuasive).
> (ii) The entry can be a general URI (or even URL), or will be
> interpreted that way.  This strikes me as a good way to get into
> trouble when files are executed in the background, as config
> files usually are.  It is probably even a security risk that
> should be documented with each impacted config file.  
> And, of course, if the first case is intended, but someone does
> a bit of shortcut programming and says "aha, this is just a URL,
> call the general URL processor", a really neat set of exploit
> attempts opens up.  So, again, if this thing is to go through, I
> suggest the security considerations section be strengthened.  A
> lot.
>      john

Patrik Fältström <paf@cisco.com>                         Cisco Systems
Consulting Engineer                                  Office of the CSO
Phone: (Stockholm) +46-8-6859131            (San Jose) +1-408-525-8509
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Received on Wednesday, 21 November 2001 04:15:29 UTC

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