Subject: RE: FW: I-D ACTION:draft-zhu-kerb-anon-00.txt

From: "Liqiang(Larry) Zhu" <[email-masked]>
Date: Fri, 21 Oct 2005 15:01:14 -0700

I sincerely believe we should finish PKINIT first. I would like to urge
every one of you start to review PKINIT-29 right away.

-- Larry

-----Original Message-----
From: Nicolas Williams [mailto:[email-masked]] 
Sent: Friday, October 21, 2005 2:58 PM
To: Martin Rex
Cc: Jeffrey Hutzelman; Liqiang(Larry) Zhu; [email-masked];
[email-masked]
Subject: Re: FW: I-D ACTION:draft-zhu-kerb-anon-00.txt

On Fri, Oct 21, 2005 at 11:54:55PM +0200, Martin Rex wrote:
> Jeffrey Hutzelman wrote:
> > (Maybe some of this belongs in kitten?)
> 
> Maybe we should migrate the thread?

The GSS discussion should move to KITTEN, yes.

But we also have to hash out the Kerberos-specific issues.  How we
represent anonymous/unidentified principals in Ticket seems quite
independent of how this feature might be used in the context of the
GSS-API.  That discussion should stay here, at least until we discover,
if we discover, that it's very closely related to the GSS issues.

Nico
--

---

From: "Liqiang(Larry) Zhu" <[email-masked]>
Date: Sun, 23 Oct 2005 12:11:04 -0700

I do not pretend I understand what is the threat you described below,
but if we just consider older implementations and make sure they do not
blindly accept the anonymous tickets thus resulting in a security
weakness, then I am positive that there are more implementations out
there today that will just ignore the critical authorization data in the
ticket than that of accepting the empty sequence in the client name, and
it is fairly clear to me that there are more 1510 implementations, than
that of 4120.

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]] On Behalf Of Jeffrey
Hutzelman
Sent: Friday, October 21, 2005 12:19 PM
To: Nicolas Williams; Liqiang(Larry) Zhu
Cc: Love H?rnquist ?strand; [email-masked]; [email-masked];
Jeffrey Hutzelman
Subject: Re: FW: I-D ACTION:draft-zhu-kerb-anon-00.txt

On Friday, October 21, 2005 02:12:47 PM -0500 Nicolas Williams 
<[email-masked]> wrote:

> On Fri, Oct 21, 2005 at 12:04:50PM -0700, Liqiang(Larry) Zhu wrote:
>> "empty SEQUENCE" is the only thing I believe we can count on that
>> older implementations will always fail if they do not support
>> anonymity as defined in this I-D.
>
> Why not have an exceedingly-unlikely-to-have-been-used name?
>
> I worry about security bugs in older implementations.

So do I.  Imagine an older implementation which renders the empty
sequence 
as the empty string (an entirely reasonable thing to do).  Now, what 
happens if the proposed anonymous principal is passed to krb5_kuserok,
and 
the .k5login file contains an empty line?  Or maybe even a comment?

We do not appear to have left ourselves any mechanism for "reserved" 
principal names which appear in all realms, aside from the 'krbtgt'
name.

-- Jeff