Part x of 67 of a multipart message

Bug #1251821 reported by Will Chapman
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
GNU Mailman
Undecided
Mark Sapiro

Bug Description

When attaching PDF files to a mailman mailing list a loop is set up where each mailing list member receives hundreds/thousands of posts.

Here is a small section of the archive:

[Alrewas NP Steering] Planning Policy Statement 25: Development and Flood Risk Practice Guide (part 1 of 67) Will Chapman (nb)
[Alrewas NP Steering] Planning Policy Statement 25: Development and Flood Risk Practice Guide (part 1 of 67) Will Chapman (nb)
[Alrewas NP Steering] Planning Policy Statement 25: Development and Flood Risk Practice Guide (part 1 of 67) Will Chapman (nb)
[Alrewas NP Steering] Planning Policy Statement 25: Development and Flood Risk Practice Guide (part 1 of 67) Will Chapman (nb)

When this section is complete (having sent 67 copies of part 1) the loop continues by sending 67 copies of part 2, etc, etc.

Any ideas how to prevent this happening - is it a mailman settings issue?

Revision history for this message
Mark Sapiro (msapiro) wrote :

It looks to me as though this is an issue with the MUA that is sending the mail to Mailman. If the same MUA is used to send the same attached PDF to an individual, what does that individual receive?

I don't think there is anything in any recent Mailman that would cause a single email message to be treated as multiple posts. What Mailman version is this? If you have access, what's in Mailman's 'post' log and what's in the incoming MTA's log?

What is the content of those archived messages?

Changed in mailman:
assignee: nobody → Mark Sapiro (msapiro)
status: New → Incomplete
Revision history for this message
Will Chapman (qbuster) wrote : Re: [Bug 1251821] Re: Part x of 67 of a multipart message

Hello Mark,

Saturday, November 16, 2013, 9:14:00 AM, you wrote:

The version of Mailman I am using (as made available by my web host
Dataflame) - is 2.1.15

> It looks to me as though this is an issue with the MUA that is sending
> the mail to Mailman. If the same MUA is used to send the same attached
> PDF to an individual, what does that individual receive?

The individual receives a message saying simply 'Part x of 67 of a multipart
message'. each message has attached a chunk of unformatted data (presumably
a 67th of the original PDF) for example:
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The size (number of parts) of the message and the number of times that
it is repeated appears to varies with the size of the original
attached PDF.

> I don't think there is anything in any recent Mailman that would cause a
> single email message to be treated as multiple posts. What Mailman
> version is this? If you have access, what's in Mailman's 'post' log and
> what's in the incoming MTA's log?

I can't see an obvious way to look at Mailman's post log or the MTA's
log - I access Mailman mailing lists via CPanel provide by my webhost.

> What is the content of those archived messages?

See above....

Thanks for your input...

> ** Changed in: mailman
> Status: New => Incomplete

> ** Changed in: mailman
> Assignee: (unassigned) => Mark Sapiro (msapiro)

--
Best regards,
 Will
  mailto:<email address hidden>

Revision history for this message
Mark Sapiro (msapiro) wrote :

OK. So there are two issues. The first is that the attachment is sent in 67 or however many partial attachments and the second is that Mailman is sending 67 copies of each partial message instead of just 1.

The first issue is due to the sending MUA (user's email client) breaking the large attachment across multiple messages (presumably Content-Type: message/partial) which have to be reassembled by the recipient's MUA. This issue is strictly due to the sending MUA and has nothing to do with Mailman.

Note that splitting messages into multiple message/partial messages is a bad idea in general, both for security because most virus and spam scanners work only with the individual partial messages rather than the reassembled content, and because many MUAs don't know how to reassemble the partial messages into a complete whole.

The second issue of Mailman sending multiple copies of each partial message is a bug somewhere. It may be something in the cPanel Exim Router/Transport definitions for Mailman or in cPanel Mailman or in Mailman itself. It is hard to say without seeing server logs, but if you could send a message with an attached PDF (preferably not TOO big) in the same way it's sent to Mailman to <email address hidden>, I can do some testing.

You probably do not have access to any server logs. If I don't find anything, you'll have to take this up with your cPanel host. See the FAQ at <http://wiki.list.org/x/sYA9>.

Revision history for this message
Will Chapman (qbuster) wrote :

Hello Mark,

Herewith an attempt to reproduce the error by attaching a similar file
to you

Saturday, November 16, 2013, 7:13:13 PM, you wrote:

> OK. So there are two issues. The first is that the attachment is sent in
> 67 or however many partial attachments and the second is that Mailman is
> sending 67 copies of each partial message instead of just 1.

> The first issue is due to the sending MUA (user's email client) breaking
> the large attachment across multiple messages (presumably Content-Type:
> message/partial) which have to be reassembled by the recipient's MUA.
> This issue is strictly due to the sending MUA and has nothing to do with
> Mailman.

> Note that splitting messages into multiple message/partial messages is a
> bad idea in general, both for security because most virus and spam
> scanners work only with the individual partial messages rather than the
> reassembled content, and because many MUAs don't know how to reassemble
> the partial messages into a complete whole.

> The second issue of Mailman sending multiple copies of each partial
> message is a bug somewhere. It may be something in the cPanel Exim
> Router/Transport definitions for Mailman or in cPanel Mailman or in
> Mailman itself. It is hard to say without seeing server logs, but if you
> could send a message with an attached PDF (preferably not TOO big) in
> the same way it's sent to Mailman to <email address hidden>, I can do some
> testing.

> You probably do not have access to any server logs. If I don't find
> anything, you'll have to take this up with your cPanel host. See the FAQ
> at <http://wiki.list.org/x/sYA9>.

--
Best regards,
 Will
  mailto:<email address hidden>

Revision history for this message
Mark Sapiro (msapiro) wrote :

Actually, you didn't send it to me. You replied to the bug report mail which sent it to <email address hidden>, and if it was split, launchpad reassembled it and attached it to the bug report. Please attach the file to an email addressed to <email address hidden>. This is the only way I will see the MIME structure and headers of the partial messages so I can test posting them to Mailman.

Note that I have done some testing with a simple, two part message that I constructed, and there was no problem with this, so I need your message to see if it creates the problem in my Mailman.

Revision history for this message
Mark Sapiro (msapiro) wrote :

I am unable to duplicate this issue in standard GNU Mailman. I think this must be something in cPanel Mailman, or more likely, in the cPanel configured exim that delivers to Mailman. Please follow up with your cPanel hosting service.

Changed in mailman:
status: Incomplete → Invalid
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