Hi Tom thanks for taking the painful but necessary step of raising a defect. Actually I dont think it is as bad as you say. The current draft is not erroneous, it is simply lacking in a non-essential though useful feature. The DN is not erroneous. It is perfectly OK and I would not suggest removing it. The reasons have already been given in my earlier discussions on Trust i.e. if the AA trusts the Grid SP then the DN of the Grid SP in the caller field (sorry may not have used the correct term here) and the DN of the user in the subject field (again may not be correct term) is sufficient to provide a perfectly good proxy service. It is also as scalable as Shibboleth is today (cf the metadata). So what you are proposing to add is a feature that will allow greater scalability and less configuring of trust meta data, since the user can dynamically delegate to a proxy to request attributes on his behalf. This is a nice additional feature to the current draft, but is not a show stopper in my opinion Regards David Tom Scavo wrote:
On Sat, Mar 22, 2008 at 11:32 AM, David Chadwick <d.w.chadwick@kent.ac.uk> wrote:
we do a dis-service to people by specifying a standard which we know to be deficient beforehand. This will cause even more delays in trying to rectify it (consider for example the OGSA Authz SAML spec, GFD 66, which was only found to be deficient after practical trials, and how long it has taken to produce replacements).
I suppose that is why the OASIS process requires three attestations (i.e., claims of successful implementation) before OASIS Standard status can be put to the vote.
My suggestion would be to raise a ballot comment now on the current OASIS draft, along with a proposed solution, so that this can be taken into account in the revision.
I tend to agree (reluctantly). What do others think?
Should the proposed solution require a <ds:KeyInfo> element and disallow an X509SubjectName identifier, or should it be more lax? That's really a tough call, I think.
If the process is anything like IETF or ISO it should not cause too much of a delay.
Such a change requires that we start from scratch, including another 60-day public review. The delay will be substantial.
Tom Scavo wrote:
On Sat, Mar 22, 2008 at 5:44 AM, David Chadwick <d.w.chadwick@kent.ac.uk> wrote:
...the inclusion of a "certificate" needs more elaboration. The inclusion for example of a user's public key certificate proves nothing more than the presence of a DN does, since it is publicly available and an untrustworth grid SP could send any PKC it wished, just as it can send any DN it wished. Therefore one needs to specify the properties of the certificate that are being transferred, which is, that the user is delegating to the grid SP to act on its behalf. A proxy certificate would do this, as would an attribute certificate.
I totally agree. Of course this requires a new attribute request handler at the Shib AA but then a new handler is required for a bare DN as well, so there's no additional penalty. I don't know that much about the VOMS AA, but I'd be surprised if handling a full certificate turned out to be much of a problem for VOMS.
We have a dilemma, however. A formal ballot is currently underway to promote the OASIS SAML V2.0 Deployment Profiles for X.509 Subjects to Committee Specification status. I fully expect this ballot to succeed. The next step after Committee Specification is OASIS Standard (but this last step requires three attestations, which is unlikely).
If we introduce a normative change to the profile such as we've been discussing, we essentially start over. Presumably the profile could travel faster through committee this time around since the bulk of it has already been vetted, but a significant delay is inevitable.
The other alternative is to specify this new extension of saml2:BaseIDAbstractType in our Attribute Exchange profile and leave the OASIS profile alone, flawed as it is. A third alternative is to do nothing.
I'm not sure what to recommend. I'll let others comment on the appropriate course of action.
Tom
Tom Scavo wrote:
Instead of *requiring* a DN, the name identifier in the query should be generalized to accommodate the entire certificate (without excluding the possibility of a naked DN in those situations where it is warranted). This can be done using <ds:KeyInfo>, something like this:
<saml:Subject> <saml:BaseID xsi:type="KeyIdentifierType"> <ds:KeyInfo>...</ds:KeyInfo> </saml:BaseID> </saml:Subject>
where KeyIdentifierType is defined as follows:
<complexType name="KeyIdentifierType"> <complexContent> <extension base="saml:BaseIDAbstractType"> <sequence> <element ref="ds:KeyInfo"/> </sequence> </extension> </complexContent> </complexType>
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***************************************************************** David W. Chadwick, BSc PhD Professor of Information Systems Security The Computing Laboratory, University of Kent, Canterbury, CT2 7NF Skype Name: davidwchadwick Tel: +44 1227 82 3221 Fax +44 1227 762 811 Mobile: +44 77 96 44 7184 Email: D.W.Chadwick@kent.ac.uk Home Page: http://www.cs.kent.ac.uk/people/staff/dwc8/index.html Research Web site: http://www.cs.kent.ac.uk/research/groups/iss/index.html Entrust key validation string: MLJ9-DU5T-HV8J PGP Key ID is 0xBC238DE5
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-- ***************************************************************** David W. Chadwick, BSc PhD Professor of Information Systems Security The Computing Laboratory, University of Kent, Canterbury, CT2 7NF Skype Name: davidwchadwick Tel: +44 1227 82 3221 Fax +44 1227 762 811 Mobile: +44 77 96 44 7184 Email: D.W.Chadwick@kent.ac.uk Home Page: http://www.cs.kent.ac.uk/people/staff/dwc8/index.html Research Web site: http://www.cs.kent.ac.uk/research/groups/iss/index.html Entrust key validation string: MLJ9-DU5T-HV8J PGP Key ID is 0xBC238DE5 *****************************************************************