Subject: Re: [ietf-dkim] Attempted summary, SSP again

From: "John R Levine" <[email-masked]>
Date: 27 Jan 2006 10:17:56 -0500

> Well, OK.  if a message has both a signature from the From: domain and
> one from someone else, does that pass?  Why or why not?

-----

From: Hector Santos <[email-masked]>

For the EXCLUSIVE policy?  Following SSP, it would be a REJECT because the
policy says no 3PS should exist.  If it does, then it should be given the
evil eye. ...

I understand what you are saying, but it is what it is. That is what the
DKIM/SSP drafts defines. It is already "solved" per se.

-----

From: Michael Thomas <[email-masked]>

I've always interpreted this as it should pass. What would be the reason
that it shouldn't? That the other signature gave it cooties?

-----

>> I'm increasingly getting the impression that we don't really understand
>> the semantics of SSP.

R's,
John
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---

From: Michael Thomas <[email-masked]>
Date: Fri, 27 Jan 2006 07:46:53 -0800

John, this would be all well and good except for the fact that even
though my name isn't on the draft I've had a great deal to do with
it from even pre-DKIM days. Hector's interpretation is wrong, and
that's not how it should be implemented. "Exclusive" is Hector's
term, not the -ssp draft's. The draft could be a little more explict
on this point, but the intent has always focused on the need for a
first party signature, not abhorance of multiple signatures.

		Mike

---

From: "Hector Santos" <[email-masked]>
Date: Fri, 27 Jan 2006 11:12:12 -0500

----- Original Message -----
From: "Michael Thomas" <[email-masked]>
To: "John R Levine" <[email-masked]>

> first party signature, not abhorance of multiple signatures.

Call it what you like.  This FIRST PARTY only signature policy is as
exclusive as you can get.

If my interpretation is wrong, then your work is all flawed. The
protocol is weak and useless.

What is strange is that more than one person told you this when you
posted your PSEUDO-CODE which was proven to be flawed and allowed
securities loopholes.  If it was because of your flawed PSEUDO CODE,
that I produced the SSP verification table/chart showing the Ideal
Boundary conditions. If you don't understand that, then I don't know
what to tell ya but you are CLEARLY not correct.  It is not our fault
you choose to ignore the input provided.

If I am wrong, then this proposal is WHACKED!

Get your act straight before you try to change the world.

--
Hector Santos, Santronics Software, Inc.
http://www.santronics.com

---

From: Michael Thomas <[email-masked]>
Date: Fri, 27 Jan 2006 08:16:41 -0800

Hector Santos wrote:
[WHACKED!]

There's no point in furthering this discussion.

		Mike

---

From: "Hector Santos" <[email-masked]>
Date: Fri, 27 Jan 2006 11:23:07 -0500

Why because I proved you wrong?  Correct me if I wrong, and I am so be
it. I am too old to feel regrets.  But so far, you have not.

This is very too important stuff and if this is your attempt to silence
me, well, no, it isn't going to work.  You are wrong and its to everyone
benefits to get it right.

Instead of fighting with me, correct the situation.  You said you are
one of the buys, so tell us. What are the correct SSP interpretations?
Follow your pseudo-code?  Is that it?  It can't be.  It is broken!  Do
you want to fix it or not?

---

From: "John R Levine" <[email-masked]>
Date: 27 Jan 2006 11:53:45 -0500

> that's not how it should be implemented.

I don't have any strong feelings about SSP other than that it's unlikely
to be useful enough in anything like its current form to merit all the
time people are putting into it.

I'd really rather we put it on the shelf and concentrated on the core
signature and verification.  We all seem to agree that we need to improve
the body canonicalization rules, but I don't see any work on that beyond
my skeleton testing setup at http://forward.sp.am.

Regards,
John Levine, [email-masked], Primary Perpetrator of "The Internet for Dummies",
Information Superhighwayman wanna-be, http://www.johnlevine.com, Mayor
"I shook hands with Senators Dole and Inouye," said Tom, disarmingly.
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---

From: Michael Thomas <[email-masked]>
Date: Fri, 27 Jan 2006 09:07:56 -0800

> my skeleton testing setup at http://forward.sp.am.

I'm sort of surprised that we haven't had any discussion about this
since the -01 draft came out. The -01 draft allows the header and body
to be canonicalized differently, and defines a new canonicalization
type "relaxed" which is primarily intended for the headers, though we
hedged by allowing it to be used for the body as well. I've been
running header=relaxed body=simple for several months at least, and
we just upgraded our pilot server at cisco a week or so ago.

As far as I can tell, the simple body canonicalization seems to work
pretty well -- I'm not sure I recall anything that I could attribute
to a failure in the body canonicalization that wouldn't defeat _any_
attempt (ie, it was mangled).

Is your test site seeing different results?

		Mike

---

From: "John R Levine" <[email-masked]>
Date: 27 Jan 2006 12:32:33 -0500

> since the -01 draft came out.

We do seem fixated on glamorous trivia, don't we?

> Is your test site seeing different results?

It's not seeing anything at all yet.  All it does is to take a message and
run it through a dozen forwarders.  We still need to build the scaffolding
to sign messages and see if the signatures still verify.

Regards,

---

From: "John R Levine" <[email-masked]>
Date: 27 Jan 2006 12:37:10 -0500

> attempt (ie, it was mangled).

I'm inclined to agree, particularly if we're not trying to survive mailing
lists.

One thing I do wonder is whether there are predictable header changes,
e.g. do forwarders try to do us a favor and rewrap headers or re-code
subject and address comments in our out of the MIME codes.  I suppose some
experiements are in order, along with beefing up some of the tools at
forward.sp.am.

Regards,

---

From: "Hector Santos" <[email-masked]>
Date: Fri, 27 Jan 2006 13:34:18 -0500

----- Original Message -----
From: "John R Levine" <[email-masked]>

> I don't have any strong feelings about SSP other than
> that it's unlikely to be useful enough in anything
> like its current form to merit all the time people
> are putting into it.

And thats too bad because you should try to understand it or get a clue
about it first before expressing any "strong feelings" or opinion about
it.  I totally disagree with your uninformed opinion about SSP.

Have a good weekend.

---

From: Frank Ellermann <[email-masked]>
Date: Fri, 27 Jan 2006 19:42:45 +0100

John R Levine wrote:

> One thing I do wonder is whether there are predictable header
> changes, e.g. do forwarders try to do us a favor and rewrap
> headers or re-code subject and address comments in our out of
> the MIME codes.  I suppose some experiements are in order,
> along with beefing up some of the tools at forward.sp.am.

Do you have a mail2news -> news2mail scenario in your tests ?
That could be one of the more "interesting" cases.  

Another interesting test would be a 2231-encoded word as (or
at the begin of) the subject, for a horrible example see also
<http://article.gmane.org/gmane.ietf.usenet.format/28707>

                          Bye, Frank

---

From: John Levine <[email-masked]>
Date: 27 Jan 2006 20:08:16 -0000

>That could be one of the more "interesting" cases.  

I find it hard to't imagine one that wouldn't break any sensible
canon scheme.  It's the same issue as mailing list software.

R's,
John

PS: Back to reading the threats draft now.
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---

From: Frank Ellermann <[email-masked]>
Date: Sun, 29 Jan 2006 11:40:34 +0100

John Levine wrote:

>> Do you have a mail2news -> news2mail scenario in your
>> tests ?  That could be one of the more "interesting"
>> cases.
 
> I find it hard to't imagine one that wouldn't break any
> sensible canon scheme.  It's the same issue as mailing
> list software.

Not necessarily, "message/news" is a proper subset of the
"message/rfc822" format, with "To:/Cc:/Bcc:" replaced by
"Newsgroups:" (simplified).

NetNews has a mandatory "From:", "Message-Id:", "Subject:",
and "Date:".  It also has the normal optional "References:"
and "Sender:" header fields.  News accepts any mail header
field that's not empty.  The latter is relevant for "Bcc:"
and empty subjects.

DKIM wants to be independent of SMTP, working everywhere
for message/rfc822.  That automatically covers digests in
the form of multipart/digest, but it should also work for
simple mail2news NetNews and maybe even application/mbox.

For the canocicalization that means to treat all cases of
field-name *WSP ":" [FWS] field-body  like an eqivalent
field-name ":" SP *WSP field-body  in the message header.

DKIM not working outside of SMTP mail would make it less
interesting, because SMTP efforts would be more efficient.

                     Bye, Frank

---

From: John Levine <[email-masked]>
Date: 29 Jan 2006 15:23:30 -0000

>"Newsgroups:" (simplified).

I actually run a bunch of mail to news gateways, and I can assure you
they all end up smashing the mail.  News is much pickier than mail
about header formats and line lengths, and my news gateway script has
all sorts of hacks to fix up common mail usages that aren't valid
news.

DKIM signatures on messages intended as news should work fine so long
as they don't sign the headers like Xref: and Path: that change on
each hop.

I can set it up, but I doubt it'll tell us much useful.

R's,
John