[SERVERBUG] failed to send mail with SA and antispam plugin

[Steffen Kaiser]

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On Thu, 15 Jan 2015, ML mail wrote:

It would be better to have the original question & discussion at the top, 
so one could cut and read nicely,

> On Wednesday, January 14, 2015 9:06 PM, Pascal Volk <user+dovecot at localhost.localdomain.org> wrote:
> On 01/14/2015 03:05 PM, ML mail wrote:
>
>> Hello,
>>
>> I am using the antispam plugin of Dovecot with SpamAssassin and in some cases when users move back mails from the Spam folder to their INBOX (false positive) they get the following error message:
>>
>> [SERVERBUG] failed to send mail

> # 2.1.7: /etc/dovecot/dovecot.conf
> # OS: Linux 3.2.0-4-amd64 x86_64 Debian 7.8 ext4

[cut]

> plugin {
> antispam_backend = pipe
> antispam_pipe_program = /usr/bin/spamc
> antispam_pipe_program_args = -d;my-mx-server.domain.com;-u;amavis
> antispam_pipe_program_notspam_args = -L;ham
> antispam_pipe_program_spam_args = -L;spam
> antispam_pipe_tmpdir = /tmp
> antispam_signature = X-Spam-Flag
> antispam_signature_missing = error
> antispam_spam = INBOX.Spam;INBOX.Junk
> antispam_trash = INBOX.trash;trash;INBOX.Trash;Trash;INBOX.Deleted Items;Deleted Items;INBOX.Deleted Messages;Deleted Messages
> antispam_verbose_debug = 1

What does the Plugin log?

[cut]
> service quota-warning {
> executable = script /usr/local/bin/quota-warning.sh
> unix_listener quota-warning {
> user = vmail
> }
> user = vmail
> }

You seem to use a virtual user configuration, so the antispam plugin 
executes spamc as user vmail, correct?

What happens if you run the program manually?
sudo -u vmail /usr/bin/spamc -d my-mx-server.domain.com -u amavis -L ham \ 
< message

You can also trace the program with a wrapper script. Replace 
antispam_pipe_program with /usr/local/bin/spamc-wrapper

==== BEGIN /usr/local/bin/spamc-wrapper
#/bin/bash

( # when and who
  date;id;
  let i=0
  # what
  echo /usr/bin/spamc "$@"
  # see embedded spaces in arguments
  for arg; do
   let i=i+1
   echo "Arg#$i: '$arg'"
  done
  # call original program
  /usr/bin/spamc "$@"
  # log return code / exit code
  rc=$?
  echo rc=$rc
  # Make sure the rc is returned back to caller
  exit $rc

  # log everything into a file
) >>/tmp/spamc-wrapper.log 2>&1
==== END

If you have lots of simultaneous calls, create one log file per call -> 
add .$$ to filename.

- -- 
Steffen Kaiser
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