ssl_vncviewer

#!/bin/sh
#
# ssl_vncviewer:  wrapper for vncviewer to use stunnel SSL tunnel.
#
# You must have stunnel(8) installed on the system and in your
# PATH (n.b. stunnel is usually in an sbin subdir).
#
# You should have "x11vnc -ssl ..." or "x11vnc -stunnel ..." 
# running as the VNC server. 
#
# usage: ssl_vncviewer [cert-args] host:display <vncviewer-args>
#
# e.g.:  ssl_vncviewer snoopy:0
#        ssl_vncviewer snoopy:0 -encodings "copyrect tight zrle hextile"
#
# [cert-args] can be:
#	-verify /path/to/cacert.pem		
#	-mycert /path/to/mycert.pem		
#
# -verify specifies a CA cert PEM file (or a self-signed one) for
#         authenticating the VNC server.
#
# -mycert specifies this client's cert+key PEM file for the VNC server to
#	  authenticate this client. 
#

VNCVIEWERCMD="vncviewer"
PATH=$PATH:/usr/sbin:/usr/local/sbin:/dist/sbin; export PATH

help() {
	head -26 $0 | tail +2
}

# grab our cmdline options:
while [ "X$1" != "X" ]
do
    case $1 in 
	"-verify")	shift; verify="$1"
                ;;
	"-mycert")	shift; mycert="$1"
                ;;
	"-h"*)	help; exit 0
                ;;
	*)	break
                ;;
    esac
    shift
done

orig="$1"
shift

# play around with host:display port:
if ! echo "$orig" | grep ':' > /dev/null; then
	orig="$orig:0"
fi

host=`echo "$orig" | awk -F: '{print $1}'`
disp=`echo "$orig" | awk -F: '{print $2}'`
if [ $disp -lt 200 ]; then
	port=`expr $disp + 5900`
fi

# try to find an open listening port via netstat(1):
use=""
if uname | grep Linux > /dev/null; then
	inuse=`netstat -ant | grep LISTEN | awk '{print $4}' | sed 's/^.*://'`
	try=5920
	while [ $try -lt 6000 ]
	do
		if ! echo "$inuse" | grep -w $try > /dev/null; then
			use=$try
			break
		fi
		try=`expr $try + 1`
	done
fi
if [ "X$use" = "X" ]; then
	# otherwise choose a "random" one:
	use=`date +%S`
	use=`expr $use + 5920`
fi

# create the stunnel config file:
if [ "X$verify" != "X" ]; then
	if [ -d $verify ]; then
		verify="CApath = $verify"
	else
		verify="CAfile = $verify"
	fi
	verify="$verify
verify = 2"
fi
if [ "X$mycert" != "X" ]; then
	cert="cert = $mycert"
fi

##debug = 7
tmp=/tmp/ssl_vncviewer.$$
cat > $tmp <<END
foreground = yes
pid =
client = yes
$verify
$cert

[vnc_stunnel]
accept = $use
connect= $host:$port
END

echo ""
echo "Using this stunnel configuration:"
cat $tmp
echo ""
sleep 1

echo "running: stunnel $tmp"
stunnel $tmp < /dev/tty > /dev/tty &
pid=$!
echo ""

# pause here to let the user supply a possible passphrase for the
# mycert key:
if [ "X$mycert" != "X" ]; then
	sleep 4
fi
sleep 2
rm -f $tmp

if [ $use -ge 5900 ]; then
	n=`expr $use - 5900`
fi

if echo "$0" | grep vncip > /dev/null; then
	# hack for runge's special wrapper script vncip.
	vncip "$@" localhost:$n
else
	$VNCVIEWERCMD "$@" localhost:$n
fi

kill $pid