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Re: Are *relative* URIs as namespace nemes considered harmful?

From: Michael Champion <Mike.Champion@softwareag-usa.com>
Date: Mon, 15 May 2000 17:53:56 -0400
Message-ID: <004101bfbeb8$127c9e40$39daa318@WORKGROUP>
To: <xml-uri@w3.org>

----- Original Message -----
From: "Tim Berners-Lee" <timbl@w3.org>
To: "Michael Champion" <Mike.Champion@softwareag-usa.com>; <xml-uri@w3.org>
Sent: Monday, May 15, 2000 4:50 PM
Subject: Are *relative* URIs as namespace nemes considered harmful?

>
> The difficult bit is that you have to store the base URI with any
document,
> and you have to give an error when you absolutely need to absolutize a
> relative URI and you have no base address. Note that the URI spec says
there
> should always be some a base address - in unix for example the file in the
> current directory if there are just a bunch of files.

Right.  As Simon St. Laurent points out, XML Base will add yet another
interesting twist here. It's easy in the static web page environment, but
figuring out what the base URI in a document that is not "stored", but
generated from an interesting combination of database queries, data
transformations, template files, etc. can be non-trivial.

>
> I am always suspicious of the argument that you are giving users enough
rope
> to hang themselves.  When the designer knows better than the user then
alarm
> bells go off.

Clearly this is a rather deep question about which reasonable people can
disagree.  I guess many of us see the dark side of unfettered user
creativity all too clearly.  Look at MS Outlook and the Windows Scripting
Host; clearly its designers shared this philosophy and made didn't try to
inhibit their users' ability to creatively write dynamic message content ...
but made it easy for malicious people to create havoc. In retrospect I'd
rather have had my creativity curtailed by a know-it-all designer than have
endured the chaos of a couple of weeks ago!

Or read David Megginson's XTech 2000 "When XML turns ugly" address for some
examples closer to home as to how intruders/vandals might exploit some of
the features of XML to raise hell when XML becomes more deeply rooted in the
Web infrastructure.  The message I took from it is to be VERY careful about
opening up security holes whereby one object or resource masquerades as
another ... and that is EXACTLY the kind of mechanism we're discussing here.

If, for the sake of argument, we don't restrict XML users' creativity and
someone figures out how to crash the (hypothetical) worldwide XML B2B
network via a hacked relative namespace URI, it's Tim Berners-Lee who's
gonna be hauled before Congress to explain why all those nice campaign
contributors lost all those billions of dollars <grin>.  I can't come up
with a plausible scenario for this, but I think it illustrates the kind of
paranoid mindset we have to take when considering the implications of
decisions made about the infrastructure of the Web.
Received on Monday, 15 May 2000 17:55:16 UTC

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