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Johannes Bauer

2008-Jul-08 08:53 UTC

[Dovecot] antispam plugin, amavis and sa-learn

Hello,

I would like to use the Dovecot antispam plugin to train SpamAssassin via
sa-learn. I compiled the plugin and got it to work with the sendmail
backend, which I tested by having it send a message to me.

As I'm calling SpamAssassin with amavisd-new, I have a system-wide Bayes
db, maintained by the amavis user. As expected, the antispam plugin calls
the configured binary as the mail user (I'm running deliver as suid, with
mixed virtual and system accounts).

My question is: How can I get the plugin to call sa-learn as user amavis?

I have tried the following things:
(1) making the amavis user's .spamassassin directory to world-writeable
and handing the path to sa-learn with the --dbpath parameter. That failed
- the IMAP client says "Move not allowed" when I try to move a message
to
or from the Spam IMAP folder.

(2) making a suid copy of sa-learn with owner amavis. This failed because
of an sperl error.

(3) editing sudoers to allow 'sudo -u amavis sa-learn' without a
password.
This works fine on the command line, but fails with the same error as (1)
when used with the plugin.

Although I compiled the plugin from git with debugging to syslog
activated, I do not get any error messages in mail.log where all messages
from dovecot are logged.

Now, I know that the methods above aren't exactly secure, so if anybody
has a different way of training SpamAssassin with the antispam plugin in a
amavis setup, I would appreciate it.

Thank you,
Johannes

Johannes Berg

2008-Jul-08 09:54 UTC

head link

[Dovecot] antispam plugin, amavis and sa-learn

On Tue, 2008-07-08 at 10:53 +0200, Johannes Bauer wrote:> Hello,
> 
> I would like to use the Dovecot antispam plugin to train SpamAssassin via
> sa-learn. I compiled the plugin and got it to work with the sendmail
> backend, which I tested by having it send a message to me.
> 
> As I'm calling SpamAssassin with amavisd-new, I have a system-wide
Bayes
> db, maintained by the amavis user. As expected, the antispam plugin calls
> the configured binary as the mail user (I'm running deliver as suid,
with
> mixed virtual and system accounts).
> 
> My question is: How can I get the plugin to call sa-learn as user amavis?
> 
> I have tried the following things:
> (1) making the amavis user's .spamassassin directory to world-writeable
> and handing the path to sa-learn with the --dbpath parameter. That failed
> - the IMAP client says "Move not allowed" when I try to move a
message to
> or from the Spam IMAP folder.
> 
> (2) making a suid copy of sa-learn with owner amavis. This failed because
> of an sperl error.
> 
> (3) editing sudoers to allow 'sudo -u amavis sa-learn' without a
password.
> This works fine on the command line, but fails with the same error as (1)
> when used with the plugin.
I have no idea. Try maybe writing a small C wrapper that checks the
arguments. Also check what user your imap is running under, normally it
would be the user who logged in unless those are virtual.

johannes
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Steffen Kaiser

2008-Jul-08 10:47 UTC

head link

[Dovecot] antispam plugin, amavis and sa-learn

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On Tue, 8 Jul 2008, Johannes Bauer wrote:
> (1) making the amavis user's .spamassassin directory to world-writeable
> and handing the path to sa-learn with the --dbpath parameter. That failed
> - the IMAP client says "Move not allowed" when I try to move a
message to
> or from the Spam IMAP folder.
> (3) editing sudoers to allow 'sudo -u amavis sa-learn' without a
password.
> This works fine on the command line, but fails with the same error as (1)
> when used with the plugin.
Hmm, "Move not allowed" from the client?

What do you see from Dovecot? I mean when you speak IMAP directly or 
trace/sniff a non-SSL connection. I have the impression, that you hit a 
situation, like:

"Cannot APPEND to a SPAM folder."

However, in this case it should not work with the sendmail binary.

For (3): did you allow all users to call sudo without password?
I mean:
  su - user sudo -u amavis sa-learn
Also, did you noticed this paragraphe in man sudo?
        -H  The -H (HOME) option sets the HOME environment variable to the
            homedir of the target user (root by default) as specified in
            passwd(5).  By default, sudo does not modify HOME (see set_home 
and
            always_set_home in sudoers(5)).

If HOME is not amavis's HOME, sa-learn might be upset.

Wrap your program in order to trace the problems of sa-learn:

#!/bin/bash

(
  id -a
  [snip] sa-learn [snip]
  rc=$?
  echo "exit code $rc"
  exit $rc
) > /tmp/antispam.out.$$ 2> /tmp/antispam.err.$$

sa-learn needs to lock the database, maybe you get race problems? I used 
to call sa-learn via --no-sync and --sync'ed in regular intervals.
Also, maybe you need a combination of -u/-C/-p.
> Although I compiled the plugin from git with debugging to syslog
> activated, I do not get any error messages in mail.log where all messages
> from dovecot are logged.
Well, my antispam logs go to syslog, but Dovecot logs to a file.
> Now, I know that the methods above aren't exactly secure, so if anybody
Dunno, but you want to train a site-wide database with information from 
the user. So what you consider unsecure in particular? If you are afraid 
of bugs in sa-learn, you should limit this ability to a certain group of 
users, because any user can push any "message" Dovecot accepts to 
sa-learn, regardless of its internal structure.

I have moved the Bayes DB to SQL to avoid the locking problems I had.

Bye,

- -- 
Steffen Kaiser
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Martijn de Munnik

2008-Jul-10 16:02 UTC

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[Dovecot] Antispam plugin, compile under Solaris

Hi,

I would like to use the antispam plugin with dovecot on Solaris. I'm  
mainly using blastwave packages and tried to compile the plugin  
without success so far.

I use the following .config file;

BACKEND=mailtrain
DOVECOT=/opt/csw/include/dovecot
INSTALLDIR=/opt/csw/lib/dovecot/modules/imap
USER=root
GROUP=root
DEBUG=syslog
PLUGINNAME=antispam

and I modified this line in Makefile;

CFLAGS += -fPIC -shared -DPLUGINNAME=$(PLUGINNAME)

I use the Sun Studio Compiler (cc: Sun C 5.9 SunOS_i386 Patch  
124868-04 2008/03/11) and gmake (also from blastwave). When I try to  
compile I got these errors;

[munnik at stevie]{~/software/dovecot-antispam}>/opt/csw/bin/gmake
cc -DHAVE_CONFIG_H -I/opt/csw/include/dovecot/ -I/opt/csw/include/ 
dovecot/src/ -I/opt/csw/include/dovecot/src/lib/ -I/opt/csw/include/ 
dovecot/src/lib-storage/ -I/opt/csw/include/dovecot/src/lib-mail/ -I/ 
opt/csw/include/dovecot/src/lib-imap/ -I/opt/csw/include/dovecot/src/ 
lib-dict/ -I/opt/csw/include/dovecot/src/lib-index/ -I/opt/csw/include/ 
dovecot/src/imap/ -o dovecot-version dovecot-version.c
"/opt/csw/include/dovecot/config.h", line 525: warning: macro  
redefined: _FILE_OFFSET_BITS
./dovecot-version > dovecot-version.h
cc -c  -DCONFIG_DEBUG -DDEBUG_SYSLOG -fPIC -shared - 
DPLUGINNAME=antispam -DHAVE_CONFIG_H -I/opt/csw/include/dovecot/ -I/ 
opt/csw/include/dovecot/src/ -I/opt/csw/include/dovecot/src/lib/ -I/ 
opt/csw/include/dovecot/src/lib-storage/ -I/opt/csw/include/dovecot/ 
src/lib-mail/ -I/opt/csw/include/dovecot/src/lib-imap/ -I/opt/csw/ 
include/dovecot/src/lib-dict/ -I/opt/csw/include/dovecot/src/lib- 
index/ -I/opt/csw/include/dovecot/src/imap/ -o debug.o debug.c
"antispam-plugin.h", line 4: cannot find include file:
"lib.h"
"antispam-plugin.h", line 5: cannot find include file:
"str.h"
"antispam-plugin.h", line 6: cannot find include file:
"client.h"
"antispam-plugin.h", line 7: cannot find include file:
"ostream.h"
"antispam-plugin.h", line 8: cannot find include file:
"imap-search.h"
"antispam-plugin.h", line 21: warning: no explicit type given
"antispam-plugin.h", line 21: syntax error before or at:  
antispam_plugin_id
"antispam-plugin.h", line 21: warning: old-style declaration or  
incorrect type for: antispam_plugin_id
"antispam-plugin.h", line 30: syntax error before or at: pool
"antispam-plugin.h", line 30: warning: undefined or missing type for:
pool
"antispam-plugin.h", line 39: warning: dubious tag declaration: struct
mailbox_transaction_context
"antispam-plugin.h", line 41: warning: dubious tag declaration: struct
mail
"antispam-plugin.h", line 42: warning: dubious tag declaration: struct
mailbox
"antispam-plugin.h", line 44: warning: dubious tag declaration: struct
mailbox_transaction_context
"antispam-plugin.h", line 66: warning: dubious tag declaration: struct
mail_storage
"antispam-plugin.h", line 67: warning: dubious tag declaration: struct
mail_storage
"antispam-plugin.h", line 68: warning: old-style declaration or  
incorrect type for: bool
"antispam-plugin.h", line 68: syntax error before or at:
mailbox_is_spam
"antispam-plugin.h", line 68: warning: dubious tag declaration: struct
mailbox
"antispam-plugin.h", line 68: warning: old-style declaration or  
incorrect type for: mailbox_is_spam
"antispam-plugin.h", line 69: warning: old-style declaration or  
incorrect type for: bool
"antispam-plugin.h", line 69: syntax error before or at:  
mailbox_is_trash
"antispam-plugin.h", line 69: warning: dubious tag declaration: struct
mailbox
"antispam-plugin.h", line 69: warning: old-style declaration or  
incorrect type for: mailbox_is_trash
"antispam-plugin.h", line 70: warning: old-style declaration or  
incorrect type for: bool
"antispam-plugin.h", line 70: syntax error before or at:  
mailbox_is_unsure
"antispam-plugin.h", line 70: warning: dubious tag declaration: struct
mailbox
"antispam-plugin.h", line 70: warning: old-style declaration or  
incorrect type for: mailbox_is_unsure
"antispam-plugin.h", line 72: warning: old-style declaration or  
incorrect type for: bool
"antispam-plugin.h", line 72: syntax error before or at:  
antispam_can_append_to_spam
"antispam-plugin.h", line 72: warning: old-style declaration or  
incorrect type for: antispam_can_append_to_spam
"antispam-plugin.h", line 73: warning: old-style declaration or  
incorrect type for: bool
"antispam-plugin.h", line 73: syntax error before or at:
keyword_is_spam
"antispam-plugin.h", line 73: warning: old-style declaration or  
incorrect type for: keyword_is_spam
"antispam-plugin.h", line 75: warning: no explicit type given
"antispam-plugin.h", line 75: syntax error before or at:  
need_keyword_hook
"antispam-plugin.h", line 75: warning: old-style declaration or  
incorrect type for: need_keyword_hook
"antispam-plugin.h", line 76: warning: no explicit type given
"antispam-plugin.h", line 76: syntax error before or at:  
need_folder_hook
"antispam-plugin.h", line 76: warning: old-style declaration or  
incorrect type for: need_folder_hook
"antispam-plugin.h", line 116: warning: dubious tag declaration:  
struct mail
"antispam-plugin.h", line 118: warning: implicit function declaration:
mail_get_stream
"antispam-plugin.h", line 118: warning: improper pointer/integer  
combination: op "="
"antispam-plugin.h", line 122: warning: dubious tag declaration:  
struct mail
"antispam-plugin.h", line 124: warning: implicit function declaration:
mail_get_headers
"antispam-plugin.h", line 124: warning: improper pointer/integer  
combination: op "="
"antispam-plugin.h", line 128: syntax error before or at: pool_t
"antispam-plugin.h", line 128: warning: undefined or missing type for:
pool_t
"antispam-plugin.h", line 130: warning: implicit function declaration:
o_stream_create_file
"antispam-plugin.h", line 130: undefined symbol: pool
"antispam-plugin.h", line 130: undefined symbol: TRUE
"antispam-plugin.h", line 130: warning: improper pointer/integer  
combination: op "="
"debug.c", line 11: warning: implicit function declaration: t_push
"debug.c", line 13: warning: implicit function declaration:
t_strconcat
"debug.c", line 13: warning: improper pointer/integer combination: op
"="
"debug.c", line 23: warning: implicit function declaration: t_pop
cc: acomp failed for debug.c
gmake: *** [debug.o] Error 2

Martijn

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