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Re: ID-typed attribute on WS-Addressing EPRs?

From: Jonathan Marsh <jmarsh@microsoft.com>
Date: Mon, 13 Mar 2006 12:19:02 -0800
Message-ID: <37D0366A39A9044286B2783EB4C3C4E801E8FF0E@RED-MSG-10.redmond.corp.microsoft.com>
To: <john.kemp@nokia.com>
Cc: <public-ws-addressing-comments@w3.org>


WS-Addressing is entering our final stage, requesting today that the specs be considered as Proposed Recommendations.  As part of our final reviews, we again looked at your rejection of our decision on the topic of providing identifiers for each header, and again concluded that we should not mandate that xml:id or some other identifier format be required.  The state of interoperability on identifiers is not perfect at the moment, as xml:id has not yet reached universal acceptance, and wsu:Id has a good degree of interoperability but isn't designed to be universally applicable.  Introducing a local id attribute would simply add more confusion to this mix.  We agree there are interoperability concerns here, but not that WS-Addressing is the best place to put a stake in the ground, lest that stake prove to be misplaced as this issue is sorted out in the larger context.

The spec does suggest that xml:id be considered: "Attribute extensibility allows use of xml:id [xml:id] for identification of these elements if desired", which we believe helps point the WG's preferred way to add identifiers, but without effectively defining profile for identifiers within the WS-Addressing spec itself.

Thank you again for bringing these issues to the WGs attention.


Thanks very much for your considered response and the attention of the 
working group on this issue.

I understand your position to be that the security layer should be 
responsible for id processing, and thus should define the name of id to 
be used on WS-Addressing elements, be it wsu:Id or xml:id.

My point, however, is that, as you noted below, it is possible to extend 
WS-Addressing. It is already possible to send arbitrary content in the 
body of a SOAP message. Such arbitrary content, not to mention content 
as defined by the WS-A working group, or WS-A content extended by some 
other party may contain an arbitrary ID-typed attribute for the purposes 
of signing. As you note, WS-A allows "anyAttribute". This extensibility, 
however, means that not only is it possible to extend WS-A, but it is 
the case that anyone wishing to interoperate reliably using WS-A, and 
sign WS-A EPRs (for example) *must* extend WS-A, by agreeing to 
interoperate using some specific ID-type attribute in restricting the 
attribute wildcard allowed by WS-A.

In summary, I do not think it is presumptous of the working group to 
choose a named attribute to identify elements such that the security 
layer can rely on all WS-A defined content appearing in messages with a 
known ID-typed attribute. It is simply an opportunity to increase the 
chances of interoperability between base implementations of this 


- John Kemp

ext Jonathan Marsh wrote:
> EPRs are attribute-extensible, allowing one to put xml:id or wsu:Id on
> an EPR for purposes of signing.  I agree xml:id is a good choice for
> identifying elements, but current security infrastructure based on
> WS-Security is probably looking for wsu:Id.  I have argued in the WG
> that it would be presumptuous of us to tell the security layer which
> form of ID it should look for.  A convention for ID is good, but will be
> most interoperable when the convention is promoted by the security
> layer, and not by WS-Addressing in possibly incompatible ways.
> The Working Group agreed with this assessment (at least the verbal
> version!) and decided to close the issue with no change.  The issue
> itself was recorded at [1], which will also have links to the resolution
> when the issues list is next updated.
> Thanks for your comment, and the opportunity to explore this topic in
> more depth.
> Jonathan Marsh
> Microsoft
> [1]
> http://lists.w3.org/Archives/Public/public-ws-desc-comments/2005Sep/0014
> .html
>>-----Original Message-----
>>From: public-ws-addressing-comments-request@w3.org [mailto:public-ws-
>>addressing-comments-request@w3.org] On Behalf Of John Kemp
>>Sent: Monday, September 05, 2005 6:32 AM
>>To: public-ws-addressing-comments@w3.org
>>Subject: ID-typed attribute on WS-Addressing EPRs?
>>I notice that WS-Addressing [1] has security recommendations that
>>include the signing of elements by those producing EPRs (and message
>>addressing properties). Such signing usually requires the presence of
>>identifying attribute on each signed element. I note that WS-
>>does not define any such attribute, but relies on a wildcard for this
>>and other attribute definitions. This seems to require that users of
>>WS-Addressing must define the use of such an attribute themselves,
>>to being able to implement the security considerations recommended by
>>WS-A. This implies that one cannot use the basic EPR and MAP
>>directly from the WS-Addressing specification (if one wishes to sign
>>EPRs and be interoperable with anyone else.)
>>In order to aid interoperability of this specification, and
>>implementation of the security considerations within, would it be
>>possible to specify the use of an ID attribute within the WS-
>>Perhaps best would be to use the recommendation specified in the
>>specification [2].
>>- JohnK
>>John Kemp
>>Nokia Corp.
>>[1] http://www.w3.org/TR/2005/CR-ws-addr-core-20050817/
>>[2] http://www.w3.org/TR/xml-id/

 [  Jonathan Marsh  ][  jmarsh@microsoft.com  ][  http://spaces.msn.com/auburnmarshes  ]
Received on Monday, 13 March 2006 20:19:17 UTC

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