#!perl -Tw
# Kasperski-AV plugin.

=head1 NAME

kavscanner - plugin for qpsmtpd which calls the Kasperski anti virus scanner

=head1 DESCRIPTION

Check a mail with the B<kavscanner> and deny if it matches a configured virus
list.

=head1 VERSION

this is B<kavscanner> version 1.0

=head1 CONFIGURATION

Add (perl-)regexps to the F<kav_deny> configuration file, one per line for the
virii you want to block, e.g.:

  I-Worm\.Sober\..*
  I-Worm\.NetSky\..*

NOTE: untested and disabled currently, need volunteers :-)

If this list does not match the virus found in the mail, you may set 
I<bcc_virusadmin viradm@your.company.com> in the plugin config to send a 
B<Bcc:> to the given mail address, i.e. the line 

  kavscanner bcc_virusadmin viradm@your.company.com 

in the F<config/plugin> file instead of just

  kavscanner

Set the location of the binary with 

  kavscanner kavscanner_bin /path/to/kavscanner

(default: F</opt/AVP/kavscanner>), NOTE: this may be broken, you want to
set B<kavscanner_bin> explicitly ;-)

=head1 NOTES

This is a merge of the clam_av plugin for qpsmtpd and qmail-scanner-queue.pl
L<http://qmail-scanner.sourceforge.net/> with my own improvements ;-)
Only tested with kavscanner 4.0.x, and bcc_virusadmin untested, as we have no
use for it currently. I wait for an official change in Qpsmtpd::Transaction
(reset/set the RCPT TO list) to activate and test the currently disabled 
B<to_virusadmin> option.

=cut

use File::Temp qw(tempfile);
use Mail::Address;
 
sub register {
  my ($self, $qp, @args) = @_;

  if (@args % 2) {
    $self->log(LOGWARN, "kavscanner: Wrong number of arguments");
    $self->{_kavscanner_bin} = "/opt/AVP/kavscanner";
  } else {
    my %args = @args;
    foreach my $key (keys %args) {
      my $arg = $key;
      $key =~ s/^/_/;
      $self->{$key} = $args{$arg};
    }
    # Untaint scanner location
    if (exists $self->{_kavscanner_bin} && 
        $self->{_kavscanner_bin} =~ /^(\/[\/\-\_\.a-z0-9A-Z]*)$/) {
      $self->{_kavscanner_bin} = $1;
    } else {
      $self->log(LOGALERT, "FATAL ERROR: Unexpected characters in kavscanner argument");
      exit 3;
    }
  } 
}
 
sub hook_data_post {
  my ($self, $transaction) = @_;
 
  my ($temp_fh, $filename) = tempfile();
  print $temp_fh $transaction->header->as_string;
  print $temp_fh "\n";
  $transaction->body_resetpos;
  while (my $line = $transaction->body_getline) {
    print $temp_fh $line;
  }
  seek($temp_fh, 0, 0);
 
  # Now do the actual scanning!
  my $cmd = $self->{_kavscanner_bin}." -Y -P -B -MP -MD -* $filename 2>&1";
  $self->log(LOGNOTICE, "Running: $cmd");
  my @output = `$cmd`;
  chomp(@output);
 
  my $result = ($? >> 8);
  my $signal = ($? & 127);
 
  unlink($filename);
  close $temp_fh;

  if ($signal) {
    $self->log(LOGWARN, "kavscanner exited with signal: $signal");
    return (DECLINED);
  }

  my $description = 'clean';
  my @infected    = ();
  my @suspicious  = ();
  if ($result > 0) {
    if ($result =~ /^(2|3|4|8)$/) {
      foreach (@output) {
        if (/^.* infected: (.*)$/) {
          # This covers the specific
          push @infected, $1;
        } elsif (/^\s*.* suspicion: (.*)$/) {
          # This covers the potential viruses
          push @suspicious, $1;
        }
      }
      $description = "infected by: ".join(", ",@infected)."; "
                    ."suspicions: ".join(", ", @suspicious);
      # else we may get a veeeery long X-Virus-Details: line or log entry
      $description = substr($description,0,60); 
      $self->log(LOGWARN, "There be a virus! ($description)");
      ### Untested by now, need volunteers ;-)
      #if ($self->qp->config("kav_deny")) {
      #  foreach my $d (keys %{$self->qp->config("kav_deny", "map")}) {
      #    foreach my $v (@infected) {
      #      return(DENY, "Virus found: $description")
      #        if ($v =~ /^$d$/i); 
      #    }
      #    foreach my $s (@suspicious) {
      #      return(DENY, "Virus found: $description")
      #        if ($s =~ /^$d$/i); 
      #    }
      #  }
      #}
      $transaction->header->add('X-Virus-Found', 'Yes');
      $transaction->header->add('X-Virus-Details', $description);
      ### maybe the spamassassin plugin can skip this mail if a virus
      ### was found (and $transaction->notes('virus_flag') exists :))
      ### ...ok, works with our spamassassin plugin version 
      ###   -- hah
      $transaction->notes('virus', $description);
      $transaction->notes('virus_flag', 'Yes');

      #### requires modification of Qpsmtpd/Transaction.pm:
      # if ($self->{_to_virusadmin}) {
      #   my @addrs = ();
      #   foreach (@{$transaction->recipients}) {
      #     push @addr, $_->address;
      #   }
      #   $transaction->header->add('X-Virus-Orig-RcptTo', join(", ", @addrs));
      #   $transaction->set_recipients(@{ Mail::Address->parse($self->{_to_virusadmin}) });
      # } elsif ($self->{_bcc_virusadmin}) {
      if ($self->{_bcc_virusadmin}) {
        foreach ( @{ Mail::Address->parse($self->{_bcc_virusadmin}) } ) {
          $transaction->add_recipient($_);
        }
      }
    } else {
      $self->log(LOGEMERG, "corrupt or unknown Kaspersky scanner/resource problems - exit status $result");
    }
  }
  
  $self->log(LOGINFO, "kavscanner results: $description");
 
  $transaction->header->add('X-Virus-Checked', 'Checked by '.$self->qp->config("me"));
  return (DECLINED);
}