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|
#!/bin/sh
#
# ssl_vncviewer: wrapper for vncviewer to use an stunnel SSL tunnel
# or an SSH tunnel.
#
# Copyright (c) 2006 by Karl J. Runge <runge@karlrunge.com>
#
# You must have stunnel(8) installed on the system and in your PATH
# (however, see the -ssh option below, in which case you will need ssh(1)
# installed) Note: stunnel is usually installed in an "sbin" subdirectory.
#
# You should have "x11vnc -ssl ..." or "x11vnc -stunnel ..."
# already running as the VNC server on the remote machine.
# (or use stunnel on the server side for any other 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
# -proxy host:port
#
# -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.
#
# -proxy try host:port as a Web proxy to use the CONNECT method
# to reach the VNC server (e.g. your firewall requires a proxy).
#
# For the "double proxy" case use -proxy host1:port1,host2:port2
# (the first CONNECT is done through host1:port1 to host2:port2
# and then a 2nd CONNECT to the destination VNC server.)
#
# See http://www.karlrunge.com/x11vnc/#faq-ssl-ca for details on SSL
# certificates with VNC.
#
# A few other args (not related to SSL and certs):
#
# -ssh Use ssh instead of stunnel SSL. ssh(1) must be installed and you
# must be able to log into the remote machine via ssh.
#
# In this case "host:display" may be of the form "user@host:display"
# where "user@host" is used for the ssh login (see ssh(1) manpage).
#
# If -proxy is supplied it can be of the forms: "gwhost" "gwhost:port"
# "user@gwhost" or "user@gwhost:port". "gwhost" is an incoming ssh
# gateway machine (the VNC server is not running there), an ssh -L
# redir is used to "host" in "host:display" from "gwhost". Any "user@"
# part must be in the -proxy string (not in "host:display").
#
# Under -proxy use "gwhost:port" if connecting to any ssh port
# other than the default (22). (even for the non-gateway case,
# -proxy must be used to specify a non-standard ssh port)
#
# A "double ssh" can be specified via a -proxy string with the two
# hosts separated by a comma:
#
# [user1@]host1[:port1],[user2@]host2[:port2]
#
# in which case a ssh to host1 and thru it via a -L redir a 2nd
# ssh is established to host2.
#
# Examples:
#
# ssl_vncviewer -ssh bob@bobs-home.net:0
# ssl_vncviewer -ssh -sshcmd 'x11vnc -localhost' bob@bobs-home.net:0
#
# ssl_vncviewer -ssh -proxy fred@mygate.com:2022 mymachine:0
# ssl_vncviewer -ssh -proxy bob@bobs-home.net:2222 localhost:0
#
# ssl_vncviewer -ssh -proxy fred@gw-host,fred@peecee localhost:0
#
# -sshcmd cmd Run "cmd" via ssh instead of the default "sleep 15"
# e.g. -sshcmd 'x11vnc -display :0 -localhost -rfbport 5900'
#
# -sshargs "args" pass "args" to the ssh process, e.g. -L/-R port redirs.
#
# -sshssl Tunnel the SSL connection thru a SSH connection. The tunnel as
# under -ssh is set up and the SSL connection goes thru it. Use
# this if you want to have and end-to-end SSL connection but must
# go thru a SSH gateway host (e.g. not the vnc server). Or use
# this if you need to tunnel additional services via -R and -L
# (see -sshargs above).
#
# ssl_vncviewer -sshssl -proxy fred@mygate.com mymachine:0
#
#
# -alpha turn on cursor alphablending hack if you are using the
# enhanced tightvnc vncviewer.
#
# -grab turn on XGrabServer hack if you are using the enhanced tightvnc
# vncviewer (e.g. for fullscreen mode in some windowmanagers like
# fvwm that do not otherwise work in fullscreen mode)
#
#
# set VNCVIEWERCMD to whatever vncviewer command you want to use.
#
VNCIPCMD=${VNCVIEWERCMD:-vncip}
VNCVIEWERCMD=${VNCVIEWERCMD:-vncviewer}
#
# Same for STUNNEL, e.g. set it to /path/to/stunnel or stunnel4, etc.
#
PATH=$PATH:/usr/sbin:/usr/local/sbin:/dist/sbin; export PATH
if [ "X$STUNNEL" = "X" ]; then
type stunnel4 > /dev/null 2>&1
if [ $? = 0 ]; then
STUNNEL=stunnel4
else
STUNNEL=stunnel
fi
fi
help() {
tail +2 "$0" | sed -e '/^$/ q'
}
gotalpha=""
use_ssh=""
use_sshssl=""
ssh_sleep=15
ssh_cmd="sleep $ssh_sleep"
if [ "X$SSL_VNCVIEWER_SSH_CMD" != "X" ]; then
ssh_cmd="$SSL_VNCVIEWER_SSH_CMD"
fi
ssh_args=""
# grab our cmdline options:
while [ "X$1" != "X" ]
do
case $1 in
"-verify") shift; verify="$1"
;;
"-mycert") shift; mycert="$1"
;;
"-proxy") shift; proxy="$1"
;;
"-ssh") use_ssh=1
;;
"-sshssl") use_ssh=1
use_sshssl=1
;;
"-sshcmd") shift; ssh_cmd="$1"
;;
"-sshargs") shift; ssh_args="$1"
;;
"-alpha") gotalpha=1
;;
"-grab") VNCVIEWER_GRAB_SERVER=1; export VNCVIEWER_GRAB_SERVER
;;
"-h"*) help; exit 0
;;
"--h"*) help; exit 0
;;
*) break
;;
esac
shift
done
if [ "X$gotalpha" != "X1" ]; then
NO_ALPHABLEND=1
export NO_ALPHABLEND
fi
orig="$1"
shift
if [ "X$use_ssh" = "X1" -a "X$use_sshssl" = "X" ]; then
if [ "X$mycert" != "X" -o "X$verify" != "X" ]; then
echo "-mycert and -verify cannot be used in -ssh mode"
exit 1
fi
fi
# play around with host:display port:
if echo "$orig" | grep ':' > /dev/null; then
:
else
orig="$orig:0"
fi
host=`echo "$orig" | awk -F: '{print $1}'`
disp=`echo "$orig" | awk -F: '{print $2}'`
if [ "X$host" = "X" ]; then
host=localhost
fi
if [ $disp -lt 200 ]; then
port=`expr $disp + 5900`
else
port=$disp
fi
# try to find an open listening port via netstat(1):
inuse=""
if uname | grep Linux > /dev/null; then
inuse=`netstat -ant | egrep 'LISTEN|WAIT|ESTABLISH|CLOSE' | awk '{print $4}' | sed 's/^.*://'`
elif uname | grep SunOS > /dev/null; then
inuse=`netstat -an -f inet -P tcp | grep LISTEN | awk '{print $1}' | sed 's/^.*\.//'`
# add others...
fi
date_sec=`date +%S`
findfree() {
try0=$1
try=$try0
use0=""
while [ $try -lt 6000 ]
do
if [ "X$inuse" = "X" ]; then
break
fi
if echo "$inuse" | grep -w $try > /dev/null; then
:
else
use0=$try
break
fi
try=`expr $try + 1`
done
if [ "X$use0" = "X" ]; then
use0=`expr $date_sec + $try0`
fi
echo $use0
}
use=`findfree 5930`
if [ $use -ge 5900 ]; then
N=`expr $use - 5900`
else
N=$use
fi
if echo "$0" | grep vncip > /dev/null; then
VNCVIEWERCMD="$VNCIPCMD"
fi
if [ "X$use_ssh" = "X1" ]; then
ssh_port="22"
ssh_host="$host"
vnc_host="localhost"
ssh=${SSH:-"ssh -x"}
if echo "$proxy" | grep "," > /dev/null; then
proxy1=`echo "$proxy" | awk -F, '{print $1}'`
proxy2=`echo "$proxy" | awk -F, '{print $2}'`
# user1@gw1.com:port1,user2@ws2:port2
ssh_host1=`echo "$proxy1" | awk -F: '{print $1}'`
ssh_port1=`echo "$proxy1" | awk -F: '{print $2}'`
if [ "X$ssh_port1" = "X" ]; then
ssh_port1="22"
fi
ssh_host2=`echo "$proxy2" | awk -F: '{print $1}'`
ssh_user2=`echo "$ssh_host2" | awk -F@ '{print $1}'`
ssh_host2=`echo "$ssh_host2" | awk -F@ '{print $2}'`
if [ "X$ssh_host2" = "X" ]; then
ssh_host2=$ssh_user2
ssh_user2=""
else
ssh_user2="${ssh_user2}@"
fi
ssh_port2=`echo "$proxy2" | awk -F: '{print $2}'`
if [ "X$ssh_port2" = "X" ]; then
ssh_port2="22"
fi
proxport=`findfree 3500`
echo
echo "Running 1st ssh proxy:"
echo "$ssh -f -p $ssh_port1 -t -e none -L $proxport:$ssh_host2:$ssh_port2 $ssh_host1 \"sleep 30\""
$ssh -f -p $ssh_port1 -t -e none -L $proxport:$ssh_host2:$ssh_port2 $ssh_host1 "sleep 30"
ssh_args="$ssh_args -o NoHostAuthenticationForLocalhost=yes"
sleep 1
stty sane
proxy="${ssh_user2}localhost:$proxport"
fi
if [ "X$proxy" != "X" ]; then
ssh_port=`echo "$proxy" | awk -F: '{print $2}'`
if [ "X$ssh_port" = "X" ]; then
ssh_port="22"
fi
ssh_host=`echo "$proxy" | awk -F: '{print $1}'`
vnc_host="$host"
fi
echo ""
echo "Running ssh:"
sz=`echo "$ssh_cmd" | wc -c`
if [ "$sz" -gt 200 ]; then
info="..."
else
info="$ssh_cmd"
fi
C=""
if [ "X$SSL_VNCVIEWER_USE_C" != "X" ]; then
C="-C"
fi
# the -t option actually speeds up typing response via VNC!!
if [ "X$SSL_VNCVIEWER_SSH_ONLY" != "X" ]; then
echo "$ssh -p $ssh_port -t $C $ssh_args $ssh_host \"$info\""
echo ""
$ssh -p $ssh_port -t $C $ssh_args $ssh_host "$ssh_cmd"
exit $?
elif [ "X$SSL_VNCVIEWER_NO_F" != "X" ]; then
echo "$ssh -p $ssh_port -t $C -L ${use}:${vnc_host}:${port} $ssh_args $ssh_host \"$info\""
echo ""
$ssh -p $ssh_port -t $C -L ${use}:${vnc_host}:${port} $ssh_args $ssh_host "$ssh_cmd"
else
echo "$ssh -f -p $ssh_port -t $C -L ${use}:${vnc_host}:${port} $ssh_args $ssh_host \"$info\""
echo ""
$ssh -f -p $ssh_port -t $C -L ${use}:${vnc_host}:${port} $ssh_args $ssh_host "$ssh_cmd"
fi
if [ "$?" != "0" ]; then
echo ""
echo "ssh to $ssh_host failed."
exit 1
fi
echo ""
if [ "X$ssh_cmd" = "Xsleep $ssh_sleep" ] ; then
sleep 1
else
# let any command get started a bit.
sleep 5
fi
echo ""
#reset
stty sane
if [ "X$use_sshssl" = "X" ]; then
echo "Running viewer:"
echo $VNCVIEWERCMD "$@" localhost:$N
echo ""
$VNCVIEWERCMD "$@" localhost:$N
exit $?
else
use2=`findfree 5960`
host0=$host
port0=$port
host=localhost
port=$use
use=$use2
N=`expr $use - 5900`
proxy=""
fi
fi
# create the stunnel config file:
if [ "X$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
mytmp() {
tf=$1
rm -rf "$tf" || exit 1
if [ -d "$tf" ]; then
echo "tmp file $tf still exists as a directory."
exit 1
elif [ -L "$tf" ]; then
echo "tmp file $tf still exists as a symlink."
exit 1
elif [ -f "$tf" ]; then
echo "tmp file $tf still exists."
exit 1
fi
touch "$tf" || exit 1
chmod 600 "$tf" || exit 1
}
if echo "$RANDOM" | grep '[^0-9]' > /dev/null; then
RANDOM=`date +%S`
fi
pcode() {
tf=$1
SSL_VNC_PROXY=$proxy; export SSL_VNC_PROXY
SSL_VNC_DEST="$host:$port"; export SSL_VNC_DEST
cod='#!/usr/bin/perl
# A hack to glue stunnel to a Web proxy for client connections.
use IO::Socket::INET;
my ($first, $second) = split(/,/, $ENV{SSL_VNC_PROXY});
my ($proxy_host, $proxy_port) = split(/:/, $first);
my $connect = $ENV{SSL_VNC_DEST};
print STDERR "\nperl script for web proxing:\n";
print STDERR "proxy_host: $proxy_host\n";
print STDERR "proxy_port: $proxy_port\n";
print STDERR "proxy_connect: $connect\n";
my $sock = IO::Socket::INET->new(
PeerAddr => $proxy_host,
PeerPort => $proxy_port,
Proto => "tcp");
if (! $sock) {
unlink($0);
die "perl proxy: $!\n";
}
my $con = "";
if ($second ne "") {
$con = "CONNECT $second HTTP/1.1\r\n";
$con .= "Host: $second\r\n\r\n";
} else {
$con = "CONNECT $connect HTTP/1.1\r\n";
$con .= "Host: $connect\r\n\r\n";
}
print STDERR "proxy_request1:\n$con";
print $sock $con;
unlink($0);
my $rep = "";
while ($rep !~ /\r\n\r\n/) {
my $c = getc($sock);
print STDERR $c;
$rep .= $c;
}
if ($rep !~ m,HTTP/.* 200,) {
die "proxy error: $rep\n";
}
if ($second ne "") {
$con = "CONNECT $connect HTTP/1.1\r\n";
$con .= "Host: $connect\r\n\r\n";
print STDERR "proxy_request2:\n$con";
print $sock $con;
$rep = "";
while ($rep !~ /\r\n\r\n/) {
my $c = getc($sock);
print STDERR $c;
$rep .= $c;
}
if ($rep !~ m,HTTP/.* 200,) {
die "proxy error: $rep\n";
}
}
if (fork) {
print STDERR "parent\[$$] STDIN -> socket\n\n";
xfer(STDIN, $sock);
} else {
print STDERR "child \[$$] socket -> STDOUT\n\n";
xfer($sock, STDOUT);
}
exit;
sub xfer {
my($in, $out) = @_;
$RIN = $WIN = $EIN = "";
$ROUT = "";
vec($RIN, fileno($in), 1) = 1;
vec($WIN, fileno($in), 1) = 1;
$EIN = $RIN | $WIN;
while (1) {
my $nf = 0;
while (! $nf) {
$nf = select($ROUT=$RIN, undef, undef, undef);
}
my $len = sysread($in, $buf, 8192);
if (! defined($len)) {
next if $! =~ /^Interrupted/;
print STDERR "perl proxy\[$$]: $!\n";
last;
} elsif ($len == 0) {
print STDERR "perl proxy\[$$]: Input is EOF.\n";
last;
}
my $offset = 0;
my $quit = 0;
while ($len) {
my $written = syswrite($out, $buf, $len, $offset);
if (! defined $written) {
print STDERR "perl proxy\[$$]: Output is EOF. $!\n";
$quit = 1;
last;
}
$len -= $written;
$offset += $written;
}
last if $quit;
}
close($in);
close($out);
}
'
echo "$cod" > $tf
chmod 700 $tf
}
ptmp=""
if [ "X$proxy" != "X" ]; then
ptmp="/tmp/ssl_vncviewer${RANDOM}.$$.pl"
mytmp "$ptmp"
pcode "$ptmp"
connect="exec = $ptmp"
else
connect="connect = $host:$port"
fi
##debug = 7
tmp=/tmp/ssl_vncviewer${RANDOM}.$$
mytmp "$tmp"
cat > "$tmp" <<END
foreground = yes
pid =
client = yes
debug = 6
$STUNNEL_EXTRA_OPTS
$verify
$cert
[vnc_stunnel]
accept = localhost:$use
$connect
END
echo ""
echo "Using this stunnel configuration:"
echo ""
cat "$tmp" | uniq
echo ""
sleep 1
echo ""
echo "Running: stunnel"
echo "$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"
echo ""
echo "Running viewer:"
echo $VNCVIEWERCMD "$@" localhost:$N
echo ""
$VNCVIEWERCMD "$@" localhost:$N
kill $pid
sleep 1
|