#!/bin/bash
#
# qmail	-- checkattach
# Author: Noel G. Mistula <noelm@meriton.com.au>
# Date: 28 June 1999 Version: 0.1
# Modified: 7 July 1999 Version: 0.3
# Modified: 7 May 2000 Version: 0.4
# Modified: 7 Dec 2001 Version: 0.5
# Modified: 14 Dec 2001 Version: 0.6
# Modified: 8 Jan 2002 Version: 0.7
# Modified: 26 Apr 2002 Version: 0.8
#

#
# This is release under the GNU/GPL.
# This is a very crude script, use at your own risk.
#
# Updated 12.07.01 by Kyle Christensen <mute@snip.net>
#
# Directions: 
# 1. Change DOMAIN var to your domain (or $1 if you want to pass the parameter into the
#    script from your .qmail-default)
# 2. Customize the bounce msg
# 3. Add/Remove file extensions
# 4. If you want logging, make sure $MAILLOG is chowned g+w to vchkpw
# 5. When you are done editing it, put "| /path/to/checkattach" in the .qmail-default for the
#    domain you are filtering attachments for ABOVE the line that specifies your normal delivery
#    practices.
#

DOMAIN=aviationlearning.com
DATE=`date +"%a,%e %b %Y %T %z (%Z)"`
HOSTNAME=`hostname -s`
MAILLOG="/var/log/maillog"
TS=`date +"%b %e %T"`
TO=`echo $RECIPIENT|awk -F$DOMAIN- '{print $2}'`

printmsg() {
	# printmsg now makes vpopmail'd to: addresses more readable, and makes the reply msg more
	# userfriendly
	echo "Received: $DATE"
	echo "From: MAILER-DAEMON@$DOMAIN"
	echo "Subject: Delivery failure notification"
	echo "Sender: MAILER-DAEMON@$DOMAIN"
	echo "To: $SENDER"
	echo "I'm sorry but your recent email to $TO couldn't be delivered."
	echo "Our mailserver doesn't accept emails with .$ATTACHTYPE file attachments for security reasons."
	echo "If you intended to attach this file, please zip up the attachment and resend your message."
	echo ""
	echo "-The $DOMAIN team"
}

checktype() {
	case $ATTACHTYPE in
        	BAS | BAT | COM | CMD | EML | EXE | INF | INI | LNK | PIF | REG | SCP | SCR | SHS | VBE | VBS | WSF | WSH)
			# Note: I am using exit 99 instead of exit 100 (no longer bouncing emails)
			# because local emails double-bounce and end up getting delivered to 
			# postmaster, which is dumb.
			# echo "$TS $HOSTNAME qmail: Checkattach debug: from $SENDER : $ATTACHMENT" >> /var/log/maillog
          		ATTACHNAME=`echo $SPLIT | awk -F: '{print $'$CUR'}'`
			echo "$TS $HOSTNAME qmail: Bounced bad attachment ($ATTACHNAME) from $SENDER to $TO" >> $MAILLOG
			printmsg | /var/qmail/bin/qmail-inject "$SENDER"
			exit 99
			;;
		*)
			;;
	esac
}

ATTACHMENT=`grep "name=" -`
# For each file in $ATTACHMENT, run checktype
SPLIT=`echo $ATTACHMENT | sed -e 's/name=/"/g' -e 's/" */:/g'`
CNT=`echo $SPLIT|awk -F: '{print NF}'`
CUR=1
while [ $CUR -lt $CNT ]; do
	ATTACHTYPE=`echo $SPLIT | awk -F: '{print $'$CUR'}'|gawk 'BEGIN {FS="."}; {print toupper($NF)}' | cut -c -3`
	checktype $ATTACHTYPE
        CUR=`expr $CUR + 1`
done
exit 0