#!/bin/sh

# $Id: ppf_mime,v 1.11 2010/07/28 00:20:06 dougb Exp $

# Please see detailed Copyright below

PATH=/bin:/usr/bin:/usr/local/bin ; export PATH
umask 077

: ${TMPDIR:=/tmp}
TDIR=`mktemp -d ${TMPDIR}/ppf_mime.XXXXXXXX` ||
    {	echo '' >&2
	echo "$0: mktemp failed, exiting" >&2
	echo '' >&2
	exit 1;}

trap "rm -f ${TDIR}/* ; rmdir ${TDIR} ; exit" 0 1 2 15

pgp_failed () {
	echo "$0: Your pgp command failed" >&2
	echo '' >&2
	cat ${TDIR}/stderr >&2
	exit 1
}

cat - >${TDIR}/raw

set_boundary () {
	boundary="${1##*boundary=}"
	boundary="${boundary#\"}"
	boundary="${boundary%%[:;\"]*}"
}

space_twiddle=space_twiddle
ll='-e $d'

while read line; do
	case "$line" in
	*micalg\=[Pp][Gg][Pp]*boundary\=*)
			set_boundary "$line"
			if [ -z "$apple_ver" ]; then
				break
			else
				micalg=true
			fi ;;
	*boundary\=*)	if [ -z "$apple_ver" ]; then
				set_boundary "$line"
			else
				[ -z "$micalg" ] && set_boundary "$line"
			fi ;;
	*delsp\=yes*)	delsp=delsp ; break ;;
	*Apple\ Message\ framework*)
			apple_ver="${line##* v}"
			apple_ver="${apple_ver%\)}"
			apple_ver="${apple_ver%\.*}"
			[ $apple_ver -ge 929 ] && unset space_twiddle
			;;
	User-Agent\:\ KMail*) unset space_twiddle ;;
	X-Mailer\:\ exmh*) unset space_twiddle ;;
	X-Mailer\:\ Mulberry*|X-Mailer\:\ The\ Bat*) rlcm="-e \$s/.\$//" ; unset ll ;;
	*micalg\=[Pp][Gg][Pp]*)	micalg=true ;;
	--${boundary}*)	[ -n "$micalg" -a -z "$apple_ver" ] && break ;;
	-----BEGIN\ PGP*) break ;;	# Last gasp if Apple but not delsp
	esac
done < ${TDIR}/raw

if [ -z "$boundary" ]; then
	echo '' >&2
	echo 'This does not appear to be a MIME-encoded message' >&2
	echo '' >&2
	exit 1
fi

csplit -s -k -f ${TDIR}/f ${TDIR}/raw "/--${boundary}/" '{9}' 2>/dev/null

# Reliably find the message body and signature
sigfile=`grep -l '^-----BEGIN PGP SIGNATURE-----$' ${TDIR}/f*`
if [ -z "$sigfile" ]; then
	# The Bat
	sigfile=`grep -l '^-----BEGIN PGP MESSAGE-----$' ${TDIR}/f*`

	if [ -z "$sigfile" ]; then
		echo 'No PGP signature found' > ${TDIR}/stderr
		pgp_failed
	fi
fi

# Assuming the signature is in body part < 10 (which is very likely)
filenum="${sigfile##*f0}"
msgfile="f0$(( $filenum - 1 ))"

# The first and last lines of the file are added by MIME encoding,
# so they must be stripped in order for the signature to verify.
# The other sed patterns canonicalize the EOL characters per RFC 3156.
if [ -n "$space_twiddle" ]; then
	sed -e '1d' $ll -e 's,
$,,g' -e 's,[ ]*$,,' -e 's,$,
,g' $rlcm ${TDIR}/$msgfile >${TDIR}/message

	# The Bat! and Mulberry clients need the last linefeed character removed, which sed cannot do
	if [ -n "$rlcm" ]; then
		awk 'NR > 1 { print h } { h = $0 } END { printf "%s", $0 }' ${TDIR}/message > ${TDIR}/awked
		mv ${TDIR}/awked ${TDIR}/message
	fi
else
	sed -e '1d' -e '$d' -e 's,
$,,g' -e 's,$,
,g' ${TDIR}/$msgfile >${TDIR}/message
fi

/usr/local/bin/gpg --verify $sigfile ${TDIR}/message 2>${TDIR}/stderr || pgp_failed

# Output will be 19 characters total so adjust status message length accordingly
date=`date +"%Y-%m-%d %H:%M:%S"`

egrep -hi '^(From|Resent-From|To|Reply-To|Resent-To|Cc|Resent-cc|Bcc|Newsgroups|Followup-To|Date|Resent-Date|Organi[sz]ation|X-Mailer|User-Agent|Subject|Resent-Subject):' ${TDIR}/f0[01]
echo ''
echo '---------------------------- PGP Command Output ----------------------------'
grep -v '^$' ${TDIR}/stderr
echo "----------- Begin PGP Signed Message Verified $date ----------"

# Remove the MIME headers from the message, and display it as a side effect
if [ -z "$delsp" ]; then
sed -e 's/^=2E/./' -e 's/^=2D/-/' -e 's/^=46/F/' -e 's/^=66/f/' ${TDIR}/message |
sed ':a
N
$!ba
s/=
\n//g' |
sed -e '1,4 s/^Content-.*/76trombones/' -e '1,4 s/^[ 	].*[a-z]=.*/76trombones/' -e '/^76trombones$/d' \
    -e 's,=20, ,g' -e 's,=3D,=,g'
else
sed -e '1,4 s/^Content-.*/76trombones/' -e '1,4 s/^[ 	].*[a-z]=.*/76trombones/' -e '/^76trombones$/d' \
    -e 's,=20, ,g' -e 's,=3D,=,g' ${TDIR}/message
fi

echo ''
echo "------------ End PGP Signed Message Verified $date -----------"

exit 0

#  Copyright (c) 2003-2010 Douglas Barton
#  All rights reserved.
#
#  Redistribution and use in source and binary forms, with or without
#  modification, are permitted provided that the following conditions
#  are met:
#  1. Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer.
#  2. 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.
#
#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
