[Mimedefang] Parser: can't flush: No space left on device and big files in /tmp

[Tom Knutson]

Lately we are seeing this error in the maillog several times a day:

Oct 28 15:10:03 mail mimedefang-multiplexor[37348]: Slave 1 stderr:
MIME::Parser: can't flush: No space left on device at
/usr/local/lib/perl5/site_perl/5.8.9/MIME/Parser.pm line 815, <FILE>
line 2700428.

The /var drive has plenty of room. The /tmp drive is nearly full with
5 large files owned by mailnull:

-rw-------  1 mailnull  wheel     167779519 Oct 28 12:39 qhNzfFSRG3

If I delete one of these large files in /tmp, they reappear after a few minutes.

This started about a week ago on a system that has been running OK for
quite a while.

FreeBSD 7.1
Mimedefang 2.64_1
clamav 0.97.6
spamassassin 3.3.2
perl 5.8.9

I have tried restarting mimedefang.

Are these big files being created by mimedefang? I didn't think it
used /tmp by default. Could this problem be caused by cleverly crafted
spam?

Suggestions on how to troubleshoot this would be appreciated.

Thanks,
Tom