qpsmtpd/plugins/virus/sophie

#!/usr/bin/perl -w
use IO::Socket;

sub register {
    my ( $self, $qp, @args ) = @_;
    $self->register_hook( "data_post", "sophiescan" );

    %{ $self->{"_sophie"} } = @args;

    # Set some sensible defaults
    $self->{"_sophie"}->{"sophie_socket"} ||= "/var/run/sophie";
    $self->{"_sophie"}->{"deny_viruses"}  ||= "yes";
    $self->{"_sophie"}->{"max_size"}      ||= 128;
}

sub sophiescan {
    my ( $self, $transaction ) = @_;
    $DB::single = 1;

    if ( $transaction->body_size > $self->{"_sophie"}->{"max_size"} * 1024 ) {
        $self->log( LOGNOTICE, "Declining due to body_size" );
        return (DECLINED);
    }

    # Ignore non-multipart emails
    my $content_type = $transaction->header->get('Content-Type');
    $content_type =~ s/\s/ /g if defined $content_type;
    unless ( $content_type
        && $content_type =~ m!\bmultipart/.*\bboundary="?([^"]+)!i )
    {
        $self->log( LOGWARN, "non-multipart mail - skipping" );
        return DECLINED;
    }

    my $filename = $transaction->body_filename;
    unless ($filename) {
        $self->log( LOGWARN, "Cannot process due to lack of filename" );
        return (DECLINED);    # unless $filename;
    }

    my $mode = ( stat( $self->spool_dir() ) )[2];
    if ( $mode & 07077 ) {   # must be sharing spool directory with external app
        $self->log( LOGWARN,
            "Changing permissions on file to permit scanner access" );
        chmod $mode, $filename;
    }

    my ($SOPHIE, $response);
    socket(\*SOPHIE, AF_UNIX, SOCK_STREAM, 0)
    	|| die "Couldn't create socket ($!)\n";

    connect(\*SOPHIE, pack_sockaddr_un $self->{"_sophie"}->{"sophie_socket"})
	|| die "Couldn't connect() to the socket ($!)\n";

    syswrite(\*SOPHIE, $filename."\n", length($filename)+1);
    sysread(\*SOPHIE, $response, 256);    
    close (\*SOPHIE);

    my $virus;

    if ( ($virus) = ( $response =~ m/^1:?(.*)?$/ ) ) {
        $self->log( LOGERROR, "One or more virus(es) found: $virus" );

        if ( lc( $self->{"_sophie"}->{"deny_viruses"} ) eq "yes" ) {
            return ( DENY,
                    "Virus"
                  . ( $virus =~ /,/ ? "es " : " " )
                  . "Found: $virus" );
        }
        else {
            $transaction->header->add( 'X-Virus-Found',   'Yes' );
            $transaction->header->add( 'X-Virus-Details', $virus );
            return (DECLINED);
        }
    }

    $transaction->header->add( 'X-Virus-Checked',
        "Checked by SOPHIE on " . $self->qp->config("me") );

    return (DECLINED);
}

=head1 NAME

sophie scanner

=head1 DESCRIPTION

A qpsmtpd plugin for virus scanning using the SOPHOS scan daemon, Sophie.

=head1 RESTRICTIONS

The Sophie scan daemon must have at least read access to the qpsmtpd spool
directory in order to sucessfully scan the messages.  You can ensure this
by running Sophie as the same user as qpsmtpd does (by far the easiest
method) or by doing the following: 

=over 4

=item * Change the group ownership of the spool directory to be a group 
of which the Sophie user is a member or add the Sophie user to the same group
as the qpsmtpd user.

=item * Change the permissions of the qpsmtpd spool directory to 0750 (this 
will emit a warning when the qpsmtpd service starts up, but can be safely
ignored).

=item * Make sure that all directories above the spool directory (to the
root) are g+x so that the group has directory traversal rights; it is not
necessary for the group to have any read rights except to the spool
directory itself.

=back

It may be helpful to temporary grant the Sophie user a shell and test to
make sure you can cd into the spool directory and read files located there.
Remember to remove the shell from the Sophieav user when you are done
testing.

Note also that the contents of config/spool_dir must be the full path to the
spool directory (not a relative path) in order for the scanner to locate the
file.

=head1 INSTALL AND CONFIG

Place this plugin in the plugin/virus directory beneath the standard
qpsmtpd installation.  If you installed Sophie with the default path, you
can use this plugin with default options (nothing specified):

=over 4

=item B<Sophie_socket>

Full path to the Sophie socket defaults to /var/run/Sophie.

=item B<deny_viruses>

Whether the scanner will automatically delete messages which have viruses.
Takes either 'yes' or 'no' (defaults to 'yes').  If set to 'no' it will add
a header to the message with the virus results.

=item B<max_size>

The maximum size, in kilobytes, of messages to scan; defaults to 128k.

=back

=head1 REQUIREMENTS

This module requires the Sophie daemon, available here:

L<http://www.clanfield.info/sophie/>

which in turn requires the libsavi.so library (available with the Sophos
Anti-Virus for Linux or Unix).

The following changes to F</etc/sophie.cfg> B<should> be made:

=over 4

=item user: qmaild

Change the "user" parameter to match the qpsmtpd user.

=item group: nofiles

Change the "group" parameter to match the qpsmtpd group.

=item umask: 0001

If you don't change the umask, only the above user/group will be able to scan.

=back

The following changes to F</etc/sophie.savi> B<must> be made:

=over 4

=item Mime: 1

This option will permit the SAVI engine to directly scan e-mail messages.

=back

=head1 AUTHOR

John Peacock <jpeacock@cpan.org>

=head1 COPYRIGHT AND LICENSE

Copyright (c) 2005 John Peacock

Based heavily on the clamav plugin

This plugin is licensed under the same terms as the qpsmtpd package itself.
Please see the LICENSE file included with qpsmtpd for details.

=cut