#!/bin/sh
#
# $Id: clamassassin.in,v 1.44 2007/03/04 13:15:37 jlick Exp $
#
# clamassassin
#
# Author: James Lick <james.lick@gmail.com>
# Website: http://jameslick.com/clamassassin/
#
# --- BEGIN LICENSE ---
#
# Copyright (c) 2003-2007, James Lick
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
# 
#     * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 
#     * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# 
#     * Neither the name of James Lick nor the names of its contributors may
# be used to endorse or promote products derived from this software without
# specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
# IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# --- END LICENSE ---

# CONFIGURATION:

# Configure your full path to where you want temporary files
TMPPATH=/tmp

# Modify Subject line with a header ala spamassassin with rewrite_subject on
# You'll want to add a trailing space before the old subject
SUBJECTHEAD="*****VIRUS***** -->  "

# Configure your full path to formail
FORMAIL=/usr/bin/formail

# Configure your full path to clamscan or clamdscan
# (If you use clamdscan, see the README for directions) 
CLAMSCAN=/usr/bin/clamdscan

# Configure options passed to clamscanner
CLAMSCANOPT="--no-summary --stdout"

# Configure flag to add clamscanner to version header
ADDSCANNERFLAG=1

# Configure the path to ClamAV's sigtool
SIGTOOL=/usr/bin/sigtool

# Configure the directory where the virus signature files are stored
SIGLOC=/var/lib/clamav

# Configure whether or not the virus signature version is added
# Default: 0.80 and higher: off, others: on
SIGVERSFLAG=0

# Configure your full path to mktemp
MKTEMP=/usr/bin/mktemp

# Paths for various basic unix utilities
RM=/usr/bin/rm
CAT=/usr/bin/cat
SED=/usr/bin/sed
ECHO=/usr/bin/echo

# END CONFIGURATION

# DO NOT MAKE CHANGES PAST THIS LINE

# Routine to cleanup and exit with an error code
bail()
{
  ${RM} -f ${MSGTMP} ${LOGTMP}
  exit ${1}
}

# Routine to bail if error code is passed
bailiferr()
{
  if [ ${1} != 0 ]
  then
    bail ${1}
  fi
}  

# Make a temporary file, or bailout if it fails
mktmp()
{
  MKTMPFILE=`${MKTEMP} -q ${TMPPATH}/${1}.XXXXXXXXXX`

  # The usual method of bailing out when mktemp fails would cause mail to
  # bounce, so instead we add extra logic to have it pass the message
  # unfiltered intead
  if [ $? != 0 ]
  then
    ${FORMAIL} -f -I "X-Virus-Status: Failed" -I \
        "X-Virus-Report: Internal error mktemp ${2} failed" \
        -I "X-Virus-Checker-Version: ${VERSION}"
    bail $?
  fi
}
  
# make temporary file for message
mktmp clamassassinmsg MSGTMP
MSGTMP=${MKTMPFILE}

# make temporary file for log
mktmp clamassassinlog LOGTMP
LOGTMP=${MKTMPFILE}

# Store the message in the message tempfile for later processing
${CAT} > ${MSGTMP}
bailiferr $?

# Set version header string
CLAMVERS=`${CLAMSCAN} -V --stdout`

if [ ${ADDSCANNERFLAG} != 0 ]
then
  SHORTCLAMSCAN=`${ECHO} ${CLAMSCAN} | ${SED} -e "s/.*\///"`
  CLAMVERS="${SHORTCLAMSCAN} / ${CLAMVERS}"
fi

if [ ${SIGVERSFLAG} != 0 ]
then
  MAJOR=`${SIGTOOL} --stdout -i ${SIGLOC}/main.cvd \
    | ${SED} -e "/^Version: /!d" -e "s/.* //"`
  MINOR=`${SIGTOOL} --stdout -i ${SIGLOC}/daily.cvd \
    | ${SED} -e "/^Version: /!d" -e "s/.* //"`
  SIGVERS="${MAJOR}.${MINOR}"
  VERSION="clamassassin 1.2.4 with ${CLAMVERS} signatures ${SIGVERS}"
else
  VERSION="clamassassin 1.2.4 with ${CLAMVERS}"
fi

# Have ClamAV check the message and save the simple results in the log
# temp file

${CLAMSCAN} ${CLAMSCANOPT} - < ${MSGTMP} > ${LOGTMP} \
  2> /dev/null
RESULT=$?

# If the message is clean, clamscan exits with status 0

if [ ${RESULT} = 0 ]
then
  # Spit out the message with a header indicating it is clean
  ${FORMAIL} -f -I "X-Virus-Status: No" -I "X-Virus-Report:" \
      -I "X-Virus-Checker-Version: ${VERSION}" < ${MSGTMP}
  bailiferr $?
else
  # If the result is 1, then a virus was detected
  if [ ${RESULT} = 1 ]
  then
    # Chop off the tempfile name off the virus message
    # This is a bit complex because there may be multiple status lines
    REASON=`${SED} -e 's/[^:]*: //' -e '/ FOUND$/!d' \
      -e 's/ FOUND$/ FOUND /' < ${LOGTMP} | ${SED} -n -e 'H;${x;s/\n//g;p;}'`
    # Extract the subject so it can be modified if SUBJECTHEAD is set 
    # Note that some versions of formail will add a leading space to the
    # subject line, so we strip off one leading space if present.
    SUBJECT=`${FORMAIL} -c -x "Subject:" < ${MSGTMP} | ${SED} -e "s/^ //"`
    # Spit out the message with the headers showing it is infected and how
    ${FORMAIL} -f -I "Subject: ${SUBJECTHEAD}${SUBJECT}" \
      -I "X-Virus-Status: Yes" -I "X-Virus-Report: ${REASON}" \
      -I "X-Virus-Checker-Version: ${VERSION}" < ${MSGTMP}
    bailiferr $?
  else
    # If the result was not 0 or 1 then some sort of error occured
    ${FORMAIL} -f -I "X-Virus-Status: Failed" -I \
      "X-Virus-Report: ${CLAMSCAN} error ${RESULT}" \
      -I "X-Virus-Checker-Version: ${VERSION}" < ${MSGTMP}
    bailiferr $?
  fi
fi

# Clean up the temp files
bail 0