Subject: RE: CONSENSUS CALL: KDC certs part 1

From: "Paul Leach" <[email-masked]>
Date: Thu, 1 Sep 2005 18:15:57 -0700

> -----Original Message-----
> From: Nicolas Williams [mailto:[email-masked]]
> Sent: Wednesday, August 31, 2005 8:43 PM
> 
> On Wed, Aug 31, 2005 at 08:28:30PM -0700, Liqiang(Larry) Zhu wrote:
> > We do need to describe "a" way how to implement this policy in the
> > security consideration section.
> 
> Since all such ways, short of name constrainsts or directories, pretty
> much amount to "local policy" I do think that "local policy" is
enough,
[Paul Leach] I'll note that "local policy" could mean two things: client
(or server) local policy (which is what I usually think of) and
organization local policy (which is where I would categorize setting of
name constraints on issued certificates by an org's PKI admins). Making
it clear of which kind one is speaking will usually help people to
understand.

> though we could also include a model of local policy (kinda like
> RFC2401bis has an ASN.1 model of the SPD).  While the latter would be
> nice I don't think we have to do it (anymore than we have to specify
> name constraints matching for KRB5Principal).
[Paul Leach] Given that improper implementation of the "local policy" of
either kind can easily render a deployment of PKINIT totally insecure, I
think that providing a model of the kind you describe is more than just
a "nice to have". 

I also think that if we're going to specify a new SAN form, then we have
an obligation to define the name constraint matching rules, since not
having them makes it more difficult to secure certain scenarios.

---

From: Nicolas Williams <[email-masked]>
Date: Fri, 2 Sep 2005 14:11:37 -0500

> it clear of which kind one is speaking will usually help people to

I've been taking "local policy" to mean policy that is local to a
device -- name constraints in certificates do not qualify as local
policy.  I would expect the WG to specify any form of policy might
impact interoperability, thus a non-normative example of local policy
using tables is fine, but anything to do with certificate extensions
(which name constraints are) would have to be specified in a normative
way.

> think that providing a model of the kind you describe is more than just

Ok.

> having them makes it more difficult to secure certain scenarios.

I agree.  Does RFC3280 (or any other PKIX RFC or BCP ) recommend or
require that name constraints be defined for new SANs?

Nico
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