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Re: Errors in the XML-Signature spec. examples (Namespace defaulting for attributes)

From: Donald E. Eastlake 3rd <dee3@torque.pothole.com>
Date: Fri, 11 Aug 2000 14:23:24 -0400
Message-Id: <200008111823.OAA05799@torque.pothole.com>
To: "John Boyer" <jboyer@PureEdge.com>
cc: "XML" <w3c-ietf-xmldsig@w3.org>

I think the answer is in A.2 and A.3 of the namespaces standard which
I had to read quite a few times to get it.  In particular, the second
"good" element below is OK because it is as if the attributes were
"n1:good:a" and "n1:a"...

Attributes without a prefix are MORE than namespace qualified.  They
are element qualified including the namespace of that elelment if any.


From:  "John Boyer" <jboyer@PureEdge.com>
To:  "Donald E. Eastlake 3rd" <dee3@torque.pothole.com>,
            "Gregor Karlinger" <gregor.karlinger@iaik.at>
Cc:  "XML" <w3c-ietf-xmldsig@w3.org>
Date:  Fri, 11 Aug 2000 09:51:31 -0700
In-Reply-To:  <200008111214.IAA05009@torque.pothole.com>

>Hi Don and Gregor,
>Actually, there seems to be need for further consideration of Gregor's
>point.  I agree, Don, that the namespace spec seems to imply in Section 5.2
>that attributes inherit namespace qualification from their parent element,
>but it does not come out and say it.
>Therefore, I kept reading and seem to have found a contradiction at the end
>of Section 5.3.  It gives an example of 'unique' attributes as follows
><!-- http://www.w3.org is bound to n1 and is the default -->
><x xmlns:n1="http://www.w3.org"
>   xmlns="http://www.w3.org" >
>  <good a="1"     b="2" />
>  <good a="1"     n1:a="2" />
>The spec says that the attributes in the second occurence of <good> is OK
>because default namespaces do not apply to attributes.  So, even though
><good> is in the default namespace and hence has the qualifier
>http://www.w3.org, this does not propagate down to qualify the attribute a.
>By extension, the attribute href you mentioned in the example of Section 5.2
>is not namespace qualified by the HTML URL.
>I will be posting this problem to XML names to ask for clarification.
>John Boyer
>Development Team Leader,
>Distributed Processing and XML
>PureEdge Solutions Inc.
>Creating Binding E-Commerce
>v: 250-479-8334, ext. 143  f: 250-479-3772
>1-888-517-2675   http://www.PureEdge.com <http://www.pureedge.com/>
>-----Original Message-----
>From: w3c-ietf-xmldsig-request@w3.org
>[mailto:w3c-ietf-xmldsig-request@w3.org]On Behalf Of Donald E. Eastlake
>Sent: Friday, August 11, 2000 5:15 AM
>To: Gregor Karlinger
>Cc: XML
>Subject: Re: Errors in the XML-Signature spec. examples (Namespace
>defaulting for attributes)
>Is this really a problem?  I thought that attributes without namespace
>prefixes were automatically considered within the context of the
>element where they occur.  In effect, the namespace qualified name of
>the element is the default "namespace" for attributes of that element.
>Take the first exampe in section 5.2 of the Namespaces document which
>you point to.  It has an <a> element using the default namespace of
>http://www.w3.org/TR/REC-html40.  This element has an href attribute.
>How are you supposed to understand what that attribute means unless
>you consider it to, in some sense, be in the "namespace" of the
>element where it occurs?  I.E., that it is part of the "Per Element
>Partition" defined in section A.2 of the Namespaces document.
>In your example below, just saying "Id" is, in effect, saying
>"XMLSignature:Signature:Id" except that syntax is prohibited...
>Presumably this is the reason for the odd wording:
>"Note that default namespaces do not apply directly to attributes."
>                                           --------
>From:  "Gregor Karlinger" <gregor.karlinger@iaik.at>
>To:  "XML" <w3c-ietf-xmldsig@w3.org>
>Date:  Fri, 11 Aug 2000 12:21:04 +0200
>Message-ID:  <NDBBIMACDKCOPBLEJCCDMEHNCJAA.gregor.karlinger@iaik.at>
>>Hi Joseph & Merlin,
>>while trying to verify Merlins signature examples with our implementation,
>>I detected the following problem, which applies to Merlins examples as
>>well as to the examples in the XML-Signature specification in chapter 2.
>>All the examples are constructed in the following way: A default namespace
>>attribute is declared in the Signature element (see line [s01] in chapter
>>which should apply to all descendants as well.
>>The problem is, that a default namespace does not apply to descendant
>>attributes, but only descendant elements
>>(see http://www.w3.org/TR/REC-xml-names/#defaulting).
>>I suggest to assign the XML-Signature namespace via a explicit namespace
>>attribute (line [s01] could look like
>>  <XMLSignature:Signature
>>    XMLSignature:Id="MyFirstSignature"
>>    xmlns:XMLSignature="http://www.w3.org/2000/07/xmldsig#">
>>Regards, Gregor
>>Gregor Karlinger
>>Phone +43 316 873 5541
>>Institute for Applied Information Processing and Communications
Received on Friday, 11 August 2000 14:21:09 UTC

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