[Mimedefang] Filtering on sender, recipient, and subject at the same time

[Craig Green]

McCarthy, Douglas J wrote:

>Hi -
>
>	I'm using MD 2.44.
>
>	What I'm trying to do is prevent automatically-generated mail
>from vacation-notification applications from going outside the company I
>work for.  The logic I'm using in the filter_recipient subroutine in 
>mimedefang-filter is basically:
>
>if ($sender =~ /@mycompany.com>?$/i) {
>    if ($recipient !~ /@mycompany.com>?$/i) {
>        if ($Subject =~ /Out of Office Autoreply/) { #Exchange vacation
>msg
>            return ('DISCARD', "ok");
>        }
>        if (system("egrep '(^User-Agent: Vacation/|^X-Mailer: vacation
>)' $CWD/HEADERS")) {                                    # UNIX vacation
>msgs
>            return ('DISCARD', "ok");
>        }
>    }
>}
>if ($ip =~ /list.of.internal.systems'.IP.addresses.here/) {
>    return ('ACCEPT_AND_NO_MORE_FILTERING', "ok");
>    }
>return ('CONTINUE', "ok");
>
>
>I'm having a lot of problems with this.
>
>First off, the system(egrep) call isn't working.  It's returning a 
>"mimedefang-multiplexor[NNNN]: Slave N stderr: grep:
>/var/spool/MIMEDefang/mdefang-aNNNaaaaNNNNNN/HEADERS: No such file or
>directory" error.  This doesn't seem right, because from what I can
>tell, that directory is indeed the right place for the HEADERS file to
>be.  (Specifying ./HEADERS instead of $CWD/HEADERS doesn't work either.)
>
>Second off, $Subject isn't available from within filter_recipient.  This
>would be okay, if I could egrep for the subject from the HEADERS file...
>but I can't, because of the "No such file or directory" error above.
>
>Any help you could give me would be greatly appreciated
>  
>

If I'm not horribly, horribly mistaken, filter_recipient is called after 
each RCPT TO: command during the SMTP conversation.  RCPT is before the 
DATA phase, when the headers--including the subject--would get 
transmitted.  Accessing HEADERS is giving "No such file" errors and 
$Subject isn't available because at that point neither exists...

I'd do what you're trying in filter_end.  Autoreplies would only go to 
one person so you don't have to worry about multiple recipients and can 
just use action_discard().

I also wouldn't use egrep to search the HEADERS file when you can just 
access the headers within the MIME entity passed in, but I don't know if 
2.44 supports that.

sub filter_end ($) {
    my($entity) = @_;

  if ($Sender =~ /\@mycompany.com>?$/i &&
    $Recipients[0]  !~ /\@mycompany.com>?$/i) {

    my $header = $entity->head; # Extract a MIME::Head object from the 
MIME::Entity object '$entity'.

    if ($header->get('User-Agent') =~ /Vacation/ ||
        $header->get('X-Mailer') =~ /vacation/ ||
        $Subject =~ /Out of Office Autoreply/ ) {
            action_discard();
    }
  }

# Spamassassin checks, etc.

}

Note: untested.  YMMV.

Regards,

Craig.
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