RE: [security-services] Comments onsstc-saml-x509-authn-attrib-profile-draft-11

["Ari Kermaier" <ari.kermaier@oracle.com>]

Thanks, you're right.
::Ari

> -----Original Message-----
> From: Greg Whitehead [mailto:greg.whitehead@hp.com]
> Sent: Wednesday, February 14, 2007 12:03 PM
> To: Ari Kermaier; security-services@lists.oasis-open.org
> Subject: Re: [security-services] Comments on
> sstc-saml-x509-authn-attrib-profile-draft-11
> 
> 
> Looking at section 3.3.4 of SAML2 core:
> 
> "If the SAML authority cannot provide an assertion with any statements
> satisfying the constraints expressed by a query or assertion 
> reference, the
> <Response> element MUST NOT contain an <Assertion> element 
> and MUST include
> a <StatusCode> element with the value
> urn:oasis:names:tc:SAML:2.0:status:Success".
> 
> Doesn't that apply in this case? If you have no attributes to 
> return then
> you have no AttributeStatement, and so you would omit the 
> Assertion (rather
> than including an empty Assertion).
> 
> -Greg
> 
> On 2/14/07 10:29 AM, "Ari Kermaier" <ari.kermaier@oracle.com> wrote:
> 
> > I suppose it's bad form to upload a draft and then post 
> comments on it myself
> > the next day, but I noticed something that might bear discussion and
> > modification.
> >
> > The X.509 attribute sharing profile discusses requirements 
> for a successful
> > samlp:Response to the samlp:AttributeQuery, and defines 
> behavior w.r.t.
> > presence/number of saml:Assertion and 
> saml:AttributeStatement elements.
> >
> > In both sstc-saml-x509-authn-attrib-profile-cd-02 [lines 
> 174-176] and
> > sstc-saml-x509-authn-attrib-profile-draft-10 [lines 
> 184-186], it requires a
> > successful Response to have exactly 1 Assertion, and exactly 1
> > AttributeStatement.
> >
> > Mailing list and meeting discussion threads arrived at the 
> conclusion that
> > there was no need to restrict a Response from carrying 
> multiple Assertion
> > and/or AttributeStatement elements. Thus, I modified the language in
> > sstc-saml-x509-authn-attrib-profile-draft-11 [lines 
> 185-186] to read:
> >
> > "Any <Assertion> element(s) MUST satisfy the following conditions:
> > The <Assertion> element MUST contain at least one 
> <AttributeStatement> element
> > that conveys the attributes of the principal to the service 
> provider."
> >
> > Thinking about implementation, however, caused me to have 
> second thoughts
> > about this language:
> >
> > Since the [SAMLCore] schema requires at least 1 Attribute 
> element in an
> > AttributeStatement, a response in which none of the 
> requested user attributes
> > could be returned (e.g., the attributes do not exist) could 
> not have an empty
> > AttributeStatement. This means that, according to either 
> the new or old
> > language, the Response could not contain an Assertion with no
> > AttributeStatement; the new language provides the ability 
> to omit the
> > Assertion entirely in this case.
> >
> > But is this the best behavior? The case of no Attributes to 
> return might be
> > better handled by returning a Response containing an 
> Assertion (with the
> > correct Subject) but with no AttributeStatement. Maybe the 
> new language should
> > be changed to require 1 or more Assertions in a successful 
> response, but allow
> > 0 or more AttributeStatements.
> >
> > Thoughts?
> >
> > Thanks,
> > Ari Kermaier
> > Oracle
> >
> 
>