Re: Hashcash-generation/check for IDN-domains

[Simon Josefsson <jas@extundo.com>]

asjo@koldfront.dk (Adam Sjøgren) writes:

>   Hi.
>
>
> I (sort-of) recently acquired the domain 'sjøgren.org'.
>
> I just tried sending an email to adam@sjøgren.org - Gnus nicely asked
> me if it should translate sjøgren.org to xn--sjgren-cya.org, and I
> happily accepted.
>
> The email arrived, but was split into the nnml:bogus group and an
> error-message occured. The following is the messages I get if I go to
> nnml:bogus and do B q on the email (after setting gnus-verbose to 10):
>
>  spam-split: widening the buffer (spam-use-crm114 requires it)
>  spam-split: calling the spam-check-hashcash function
>  Error in `nnmail-split-methods'; using `bogus' mail group
>  This message would go to bogus
>
> It seems that the hashcash generated is somehow invalid and/or the
> check is (too) fragile. I'm not sure which.

The X-hashcash header sent appeared to contain the non-ASCII
characters, which I believe is wrong.  So it is the generation that is
faulty.  Since, if I recall correctly, it copy the content from
To/From/Cc, it probably should do its own IDN-processing.  I'm not
sure how that would interfact with answering 'n' at the query you
refer to though.  Perhaps that query is simply wrong?  It doesn't make
sense to send mail to non-ASCII domains ever, does it?  So Gnus should
attempt to translate non-ASCII to xn--* via libidn, or refuse to send
the message.  Then the hashcash code could also unconditionally
perform idn-encoding.  Not sure what should happen if idn-encoding
inside the hashcash cookie generation fail though.  Leave the
X-hashcash as-is, with non-ASCII characters?  Or remove the header?

When we knew some more answers to these questions, I can try to
implement them...

> The entire email is:
>
> #v+
> X-From-Line: asjo@koldfront.dk  Tue Sep 27 14:34:08 2005
> Return-Path: <asjo@koldfront.dk>
> X-Original-To: asjo@topper.koldfront.local
> Delivered-To: asjo@topper.koldfront.local
> Received: from virgil.koldfront.dk (virgil.koldfront.local [192.168.1.111])
> 	(using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
> 	(No client certificate requested)
> 	by topper.koldfront.dk (Postfix) with ESMTP id 60489F0000E3
> 	for <asjo@topper.koldfront.local>; Tue, 27 Sep 2005 14:34:08 +0200 (CEST)
> Received: by virgil.koldfront.dk (Postfix)
> 	id 50B7F3A8AF59; Tue, 27 Sep 2005 14:37:14 +0200 (CEST)
> Delivered-To: asjo@koldfront.dk
> Received: by virgil.koldfront.dk (Postfix, from userid 1010)
> 	id 4F0A93A8AF5A; Tue, 27 Sep 2005 14:37:14 +0200 (CEST)
> Received: from topper.koldfront.dk (gateway.koldfront.dk [192.168.1.1])
> 	(using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
> 	(No client certificate requested)
> 	by virgil.koldfront.dk (Postfix) with ESMTP id D769E3A8AF59
> 	for <adam@xn--sjgren-cya.org>; Tue, 27 Sep 2005 14:37:13 +0200 (CEST)
> Received: by topper.koldfront.dk (Postfix, from userid 1000)
> 	id AB77AF0000E3; Tue, 27 Sep 2005 14:34:06 +0200 (CEST)
> From: asjo@koldfront.dk (Adam =?iso-8859-1?Q?Sj=F8gren?=)
> To: adam@xn--sjgren-cya.org
> Subject: Test
> Organization: koldfront - analysis & revolution, Copenhagen, Denmark
> X-Face: )qY&CseJ?.:=8F#^~GcSA?F=9eu'{KAFfL1C3/A&:nE?PW\i65"ba0NS)97,Q(^@xk}n4Ou
>  rPuR#V8I(J_@~H($[ym:`K_+]*kjvW>xH5jbgLBVFGXY:(#4P>zVBklLbdL&XxL\M)%T}3S/IS9lMJ
>  ^St'=VZBR<gm`!Dj`dIpp?+$"$l_'JKDN\w-jB;fo0Qy}Tbw
> X-Hashcash: =?iso-8859-1?Q?1=3A24=3A050927=3Aadam=40sj=F8gren=2Eorg=3A=3A+?=
>  =?iso-8859-1?Q?OOJ2Vgcu8oOshd2=3A0ZBhK?=
> Date: Tue, 27 Sep 2005 14:34:01 +0200
> X-Gnus-Mail-Source: file:/var/mail/asjo
> Message-ID: <878xxid70m.fsf@koldfront.dk>
> User-Agent: Gnus/5.110004 (No Gnus v0.4) XEmacs/21.4.17 (linux)
> MIME-Version: 1.0
> Content-Type: text/plain; charset=iso-8859-1
> Content-Transfer-Encoding: 8bit
> X-Spam-Checker-Version: SpamAssassin 3.0.3 on virgil.koldfront.dk
> X-Spam-Level: 
> X-Spam-Status: No, score=-6.1 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 
> 	autolearn=ham version=3.0.3
> Lines: 6
> Xref: topper bogus:19
>
> 1-2
>
> -- 
>  "Vi falder samme vej eller ej"                               Adam Sjøgren
>                                                          asjo@koldfront.dk
>
>
>
> #v-
>
> It looks like the hashcash-header was qp-encoded due to the 'ø' in the
> domain and this somehow confuses hashcash.el when checking it?
>
>
>   Best regards,
>
> -- 
>  "Vi falder samme vej eller ej"                               Adam Sjøgren
>                                                          asjo@koldfront.dk