[Dovecot] Trouble implementing Antispam plug-in for Dovecot

[Ben Johnson]

On 9/19/2012 6:19 PM, Tom Hendrikx wrote:
> On 19/09/12 23:41, Ben Johnson wrote:
>>
>>
>> On 9/11/2012 10:40 AM, Ben Johnson wrote:
>>> You nailed it, Ben. Thanks!
>>>
>>> I downloaded/installed the dovecot-dev package from the same maintainer
>>> and was able to build Antispam without issue.
>>>
>>> The hang-up now seems to be with my configuration.
>>>
>>> I'm seeing the following error in my email client whenever I attempt to
>>> move an email message from, say, Inbox to Junk folder:
>>>
>>> [SERVERBUG] BUG Unknown internal error.
>>>
>>> Nothing at all appears in syslog when this happens.
>>>
>>> I followed the instructions at http://wiki2.dovecot.org/Plugins/Antispam
>>> , to the letter, I believe.
>>>
>>> The relevant portions of my configuration are as follows:
>>>
>>> ---------------------
>>> protocol imap {
>>>   mail_plugins = quota imap_quota antispam
>>> }
>>>
>>> plugin {
>>>   quota = dict:user::file:/var/vmail/%d/%n/.quotausage
>>>   sieve = /var/vmail/%d/%n/.sieve
>>>
>>>   antispam_backend = MAILTRAIN
>>>   antispam_mail_sendmail = /usr/bin/sa-learn-pipe.sh
>>>   antispam_mail_spam = --spam
>>>   antispam_mail_notspam = --ham
>>>   antispam_spam_pattern_ignorecase = spam;junk
>>> }
>>> ---------------------
>>>
>>> The permissions and execute bit are set in accordance with other
>>> executables in the same directory:
>>>
>>> # ls -lah /usr/bin/ | grep -i "sa-learn-pipe.sh"
>>> -rwxr-xr-x  1 root root     297 Sep  5 11:17 sa-learn-pipe.sh
>>>
>>> I would provide more log content, but the debug options seem to be gone
>>> in the forked, >= 2.0 version of this plug-in.
>>>
>>> Any ideas are very much appreciated.
>>>
>>> Thanks,
>>>
>>> -Ben
>>
>> Given that nobody shared any insight here, I decided to stand-up a
>> completely new VM with Ubuntu 12.04 LTS and see if the same error occurs.
>>
>> While the error is different this time around, I am still unable to get
>> any variant of the dovecot-antispam plug-in working.
>>
>> When I attempt to use the current packages from Ubuntu 12.04.1 LTS, and
>> I use the above configuration, my syslog fills-up with the following:
>>
>> dovecot: imap-login: Login: user=<user at example.com>, method=PLAIN,
>> rip=10.0.1.57, lip=10.0.1.8, mpid=2879, TLS
>> dovecot: master: Error: service(imap): child 2879 returned error 3
>>
>> Surprisingly, I can find only two other mentions of "error 3" anywhere
>> on the Internet. Those mentions were from another user to this mailing list:
>>
>> http://www.dovecot.org/list/dovecot/2012-August/067787.html
>> http://www.dovecot.org/list/dovecot/2012-August/067814.html
>>
>> The lack of "error 3" ubiquity leads me to believe that I must be doing
>> something stupid.
>>
>> There's no question that this behavior is related to the
>> antispam-plugin, because when I commented-out the relevant lines in
>> Dovecot's configuration file, the error does not occur.
>>
>> I have followed the instructions at
>> http://wiki2.dovecot.org/Plugins/Antispam to the letter, and this is the
>> result.
>>
>> The only instance in which I diverged from the Wiki article is that I
>> used the Ubuntu-provided dovecot-antispam package (instead of compiling
>> the plug-in from source).
>>
>> I am trying to use the "mailtrain" back-end, per the above-cited Wiki
>> article, to call SpamAssassin's "sa-learn" utility for real-time learning.
>>
>> I am not using the SpamAssassin daemon (spamd).
>>
>> I'm about to throw in the towel on this plug-in, so any help would be
>> greatly appreciated.
>>
>> Thank you,
>>
>> -Ben
> 
> There are 2 versions of the dovecot-antispam package. The original
> version was created by Johannes Berg, then died almost a silent death,
> and was forked by Eugene Paskevitch. Later Johannes revived his original
> version somewhat.
> 
> The ubuntu package is based on the 'revived Johannes fork' [1], while
> the documentation on the dovecot wiki describes the 'Eugene fork'. [2]
> 
> [1] https://launchpad.net/ubuntu/precise/+source/dovecot-antispam/+copyright
> [2] http://wiki2.dovecot.org/Plugins/Antispam
> 
> Thus you'll need to choose which plugin you want, then follow the
> complete procedure for that plugin only. They both can do what you want,
> but building and configuration are slightly different.
> 
> It would be nice if Johannes and Eugene would either agree on a single
> version of the plugin, or rename one of the forks so they don't get
> mixed up that easily. I'm not sure if that has been discussed (on- or
> off-list) in the past.
> 
> FWIW: I used the 'original Johannes fork' with dovecot 1.x, and the
> 'Eugene fork' with 2.0.x, both with delight. Didn't get myself to
> upgrade to 2.1 yet, so no experience there.
> 
> --
> Tom
> 

Thank you for your timely response, Tom. Much appreciated.

Your remarks clear-up a lot of the confusion for me. I didn't realize
that the "revived Johannes fork" made a comeback for Dovecot 2. Nor did
I realize that this is the version that is packaged with Ubuntu 12.04.

Given that I'm more-or-less forced to work with Ubuntu LTS, I would
prefer to use the OS's package management system wherever possible. I
suppose, by extension, that I would prefer to use the "revived Johannes
fork".

I've tried the Johannes versions (for both Dovecot 1 and Dovecot 2), but
am unable to get either to work the way I want (mailtrain back-end with
real-time calls to sa-learn, as described in the Dovecot 2/Eugene Wiki
article). Shouldn't the basic tenets of each version of the plug-in apply?

Where should I start, in the way of seeking support? Basically, I intend
to use the Johannes version, but I want to configure it in the manner
described in the Eugene version Wiki article.

I've already described (rather exhaustively) what happens when I attempt
to use the Johannes version and adapt the Eugene version instructions.

I'm curious to know what method you've used over the years with such
glowing success. Which back-end did you use with Dovecot 1/Johannes? How
about with Dovecot 2/Eugene?

Thanks again,

-Ben