Admin address over quota causes bounce loop

[Brong-users]

X-Mailman-Version: 2.1.9.cp1

Hi,

I'm not the administrator of the Mailman instance,
just the poor sysadmin of a mail service who was
woken in the middle of the night by our MX servers
being severely overloaded by a mail loop.

One of our users hit their quota in Cyrus and hence
their mail was bouncing. This user is the admin for
a Mailman list, and the list has been configured to
forward all bounces to the admin.

The message was:

--===============2109117388==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit

As list administrator, your authorization is
requested for the
following mailing list posting:

    List: *****
    From: *****
    Subject: *****
    Reason: Message body is too big: 7519566 bytes
with a limit of 40 KB

At your convenience, visit:

    http://...

to approve or deny the request.

And above that stacks of:

--===============0756822160==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit

The attached message was received as a bounce, but
either the bounce
format was not recognized, or no member addresses
could be extracted
from it. This mailing list has been configured to
send all
unrecognized bounce messages to the list
administrator(s).

For more information see:
http://.../bounce

I will point the owners of the offending bug at this
thread so they can provide more specific information
if they wish, without giving their privacy away.

Bron.

[http://sourceforge.net/tracker/index.php?func=detail&aid=1567408&group_id=103&atid=100103]

[Mark Sapiro (msapiro)]

I am moving this to bugs as it is a bug report, not a patch.

Your list owners don't need to provide any additional
information. I understand exactly what's happening here.
(but see below)

There are two issues. The first is that we don't protect
against this loop and I think we should try to. I'll look
into fixing it, although I suspect it will not be easy as
anything I might put in the 'unrecognized bounce' message to
try to detect a loop can be munged or dropped by the MTA
that returns the next bounce.

The other part of the issue is that the MTA that is
returning the 'over quota' denial is not returning an RFC
3464 or RFC 1894 compliant DSN or any of the many other
formats that Mailman heuristically recognizes. If it were,
it would be recognized and not sent back to the list owner.

There is one thing you can provide and that is the actual
'delivery status' part of the unrecognized bounce. You can
alter addresses and domains if you wish for privacy, but if
I have the exact message including headers, I can add a
recognizer for it. What I need is the contents of the
message/rfc822 part that follows the "The attached message
was received" notice you quote above up to the first
"original message follows". I.e., just the DSN part and it's
headers, not any of the multiple preceeding messages/DSNs/etc.