[Mailman-Users] encoding errors

[Mark Sapiro]

Heather Madrone wrote:

>At 9:03 PM -0500 4/13/05, Larry Stone wrote:
>>On 4/13/05 8:20 PM, Brad Knowles at brad at stop.mail-abuse.org wrote:
>> > At 6:14 PM -0700 2005-04-13, Heather Madrone wrote:
>> >>  Does anyone know why there are so many encoding errors with posts to this
>>>>  list?
>>>
>>> Encoding errors?  What do you mean?
>>
>>I think she means this:
>>[Error: Formatting error: Non-hexadecimal character in QP encoding]
>>which I see in many list messages when logged into the shell on my computer
>>and reading with pine (pine 4.58 running on MacOS X 10.3.8; for
>>completeness, the MTA is whatever version of postfix came with Mac OS X
>>10.3). I saw it in a message tonight:
>>
>>Date: Wed, 13 Apr 2005 18:22:26 -0500
>>From: Jess Mooers <jmooers at landmannassoc.com>
>>To: Mailman Users List <mailman-users at python.org>
>>Subject: [Mailman-Users] MailMan Not Sending
>
>Yes, that's exactly what I'm talking about.  I'm wondering if it happens when
>the messages are converted to plain text.  Or maybe with the handling of extended
>ASCII characters.
>
>On this list, I see it with about 5% of the posts.  I'm running the same version of
>Mailman as this list, and it doesn't happen on my list.
>
>It seems like bad advertising for Mailman, and I'd be interested in helping to track
>down the problem.

I believe the issue is this. The last line of the list footer for this
list is:

>Security Policy: http://www.python.org/cgi-bin/faqw-mm.py?req=show&amp;file=faq01.027.htp

Equal signs are special in quoted-printable encoding; the introduce a
two hex digit character code. Thus in quoted-printable encoding, '=fa'
stands for the character whose hex value is FA, but '=sh' is an error.

Now, normally, when the body of a message has content type other than
text/plain or a character set that is different from the list's
character set, the footer is added as a separate MIME part (see
http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq04.039.htp).

I thought that was also the case when the body was encoded
quoted-printable or base64. I'm still pretty sure it is the case with
base64, but apparently it isn't the case with quoted-printable.

What is happening here is the original post has

Content-Transfer-Encoding: quoted-printable

and the footer is just being added to the end of the body. Then the
recipients MUA decodes the quoted-printable message body which
includes the footer and encounters the error on the '=sh'.

I haven't looked at the Mailman code for this, but the solution would
be to insure that if the message has Content-Transfer-Encoding: other
than 7bit or 8bit, the footer is placed in a separate MIME part. Or,
in this case if possible, to link to the FAQ article without using
'=', but given the FAQ wizard, I don't think it is possible. Note that
neither %3D nor &#3D; is an acceptable substitute for '=' in this
context in the cgi URL


>A rolling stone gathers no mass.

Actually, according to special relativity, if it is accelerating, it
does :-)

--
Mark Sapiro <msapiro at value.net>       The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan