Re: [xml] C14N does not handle empty-namespace declarations as the implementation in Java

[Aleksey Sanin <aleksey aleksey com>]

Arne,

Could you please give an exact example that shows the problem
using the testC14N command? For example, for the xml snippet
from your previous email I generated C14N and I see no xmlns=""
definitions:

$ testC14N --with-comments test.xml > test-c14n.xml

Thanks
Aleksey

Arne Mueller wrote:
> Am Sonntag, den 24.08.2008, 21:21 -0700 schrieb Aleksey Sanin:
> > Hi, Arne!
> >
> > Sorry, but as I have replied in xmlsec mailing list, I believe
> > that libxml2 is doing the right thing here.
> >
> > Aleksey
>
> Hi Aleksey,
> you might be perfectly right with adding one empty namespace.
>
> But I think one thing is buggy non the less, in the c14n-specification
> it says:
>
> <quote>
> 4.6 Superfluous Namespace Declarations
> Unnecessary namespace declarations are not made in the canonical form.
> Whether for an empty default namespace, a non-empty default namespace,
> or a namespace prefix binding, the XML canonicalization method omits a
> declaration if it determines that the immediate parent element in the
> canonical form has an equivalent declaration in scope. The root document
> element is handled specially since it has no parent element. All
> namespace declarations in it are retained, except the declaration of an
> empty default namespace is automatically omitted.
> </quote>
>
> Thus, there should be at most one empty namespace declaration, because
> an parent element has already defined the empty namespace declaration.
> The same holds for the redefinition of "dsig" in the XPath element.
>
> Arne
<dsig:SignedInfo xmlns="http://www.w3.org/2000/09/xmldsig#"; xmlns:dsig="http://www.w3.org/2000/09/xmldsig#";>
<dsig:CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315";></dsig:CanonicalizationMethod>
<dsig:SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1";></dsig:SignatureMethod><dsig:Reference URI="">
<dsig:Transforms>
<dsig:Transform Algorithm="http://www.w3.org/TR/1999/REC-xpath-19991116";><dsig:XPath>
count(ancestor-or-self::dsig:Signature  | here()/ancestor::dsig:Signature[1])
&gt;  count(ancestor-or-self::dsig:Signature)
</dsig:XPath>
</dsig:Transform>
</dsig:Transforms>
<dsig:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1";></dsig:DigestMethod>
<dsig:DigestValue>nDF2V/bzRd0VE3EwShWtsBzTEDc=</dsig:DigestValue></dsig:Reference>
</dsig:SignedInfo>

<dsig:SignedInfo 
	xmlns="http://www.w3.org/2000/09/xmldsig#";
	xmlns:dsig="http://www.w3.org/2000/09/xmldsig#";>
<dsig:CanonicalizationMethod
	Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
<dsig:SignatureMethod
	Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/><dsig:Reference URI="">
<dsig:Transforms>
<dsig:Transform
Algorithm="http://www.w3.org/TR/1999/REC-xpath-19991116";><dsig:XPath
xmlns:dsig="http://www.w3.org/2000/09/xmldsig#";>
count(ancestor-or-self::dsig:Signature  | here()/ancestor::dsig:Signature[1])
&gt;  count(ancestor-or-self::dsig:Signature)
</dsig:XPath>
</dsig:Transform>
</dsig:Transforms>
<dsig:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
<dsig:DigestValue>nDF2V/bzRd0VE3EwShWtsBzTEDc=</dsig:DigestValue></dsig:Reference>
</dsig:SignedInfo>