SSH on Multiple ports Fedora Core 4
John Gallagher
john.gallagher at ciosystems.com
Wed Nov 30 00:50:38 UTC 2005
> -----Original Message-----
> From: John Gallagher [mailto:john.gallagher at ciosystems.com]
>
>
> Part of my original post was that I ran this on FC1.
> Actually it is running on FC1, however the same behavior can
> be seen if you use the service command to start/stop the one
> of the processes. Apparently because the last process
> started becomes the PID, the start, stop function of the init
> script can effect both processes.
>
> /var/run/sshd.pid
> Contains the process ID of the sshd listening
> for connections (if
> there are several daemons running concurrently
> for different
> ports, this contains the process ID of the one
> started last).
> The content of this file is not sensitive; it
> can be world-read-
> able.
>
> Does anyone know of a way to change that behavior short of
> compiling another binary that uses another PID?
I did some more research on this issue and figured out a work around to the
problem above.
I thought (incorrectly) that you could define the PID File in the init
script because it has a variable for it:
PID_FILE=/var/run/sshd.pid
It turns out that the init script never sources this variable for any
purpose.
Man of sshd_config indicated that you could add this option to change the
default pid file.
PIDFILE /var/run/sshd-ext.pid
This in fact created a new PID, however the init script would still kill
this process.
I am not a shell scripting expert but my guess is that it was killing it
because it is doing a killproc on $SSHD -TERM where $SSHD is the path to the
executable /usr/sbin/sshd.
{
echo -n $"Stopping $prog: "
if [ -n "`pidfileofproc $SSHD`" ] ; then
killproc $SSHD -TERM
else
failure $"Stopping $prog"
fi
RETVAL=$?
[ "$RETVAL" = 0 ] && rm -f /var/lock/subsys/sshd
echo
}
To get it working I needed to do the following:
Copy the binary in /usr/sbin/sshd to /usr/sbin/sshd-ext
Copy /etc/pam.d/sshd to /etc/pam.d/sshd-ext
Modify the init script by replacing sshd with sshd-ext:
#!/bin/bash
#
# Init file for OpenSSH server daemon
#
# chkconfig: 2345 55 25
# description: OpenSSH server daemon
#
# processname: sshd-ext
# config: /etc/ssh/ssh_host_key
# config: /etc/ssh/ssh_host_key.pub
# config: /etc/ssh/ssh_random_seed
# config: /etc/ssh/sshd_config-ext
# pidfile: /var/run/sshd-ext.pid
# source function library
. /etc/rc.d/init.d/functions
# pull in sysconfig settings
[ -f /etc/sysconfig/sshd-ext ] && . /etc/sysconfig/sshd-ext
RETVAL=0
prog="sshd-ext"
# Some functions to make the below more readable
KEYGEN=/usr/bin/ssh-keygen
SSHD=/usr/sbin/sshd-ext
RSA1_KEY=/etc/ssh/ssh_host_key
RSA_KEY=/etc/ssh/ssh_host_rsa_key
DSA_KEY=/etc/ssh/ssh_host_dsa_key
PID_FILE=/var/run/sshd-ext.pid
do_rsa1_keygen() {
if [ ! -s $RSA1_KEY ]; then
echo -n $"Generating SSH1 RSA host key: "
if $KEYGEN -q -t rsa1 -f $RSA1_KEY -C '' -N '' >&/dev/null;
then
chmod 600 $RSA1_KEY
chmod 644 $RSA1_KEY.pub
if [ -x /sbin/restorecon ]; then
/sbin/restorecon $RSA1_KEY.pub
fi
success $"RSA1 key generation"
echo
else
failure $"RSA1 key generation"
echo
exit 1
fi
fi
}
do_rsa_keygen() {
if [ ! -s $RSA_KEY ]; then
echo -n $"Generating SSH2 RSA host key: "
if $KEYGEN -q -t rsa -f $RSA_KEY -C '' -N '' >&/dev/null;
then
chmod 600 $RSA_KEY
chmod 644 $RSA_KEY.pub
if [ -x /sbin/restorecon ]; then
/sbin/restorecon $RSA_KEY.pub
fi
success $"RSA key generation"
echo
else
failure $"RSA key generation"
echo
exit 1
fi
fi
}
do_dsa_keygen() {
if [ ! -s $DSA_KEY ]; then
echo -n $"Generating SSH2 DSA host key: "
if $KEYGEN -q -t dsa -f $DSA_KEY -C '' -N '' >&/dev/null;
then
chmod 600 $DSA_KEY
chmod 644 $DSA_KEY.pub
if [ -x /sbin/restorecon ]; then
/sbin/restorecon $DSA_KEY.pub
fi
success $"DSA key generation"
echo
else
failure $"DSA key generation"
echo
exit 1
fi
fi
}
do_restart_sanity_check()
{
$SSHD -t
RETVAL=$?
if [ ! "$RETVAL" = 0 ]; then
failure $"Configuration file or keys are invalid"
echo
fi
}
start()
{
# Create keys if necessary
do_rsa1_keygen
do_rsa_keygen
do_dsa_keygen
echo -n $"Starting $prog: "
$SSHD $OPTIONS && success || failure
RETVAL=$?
[ "$RETVAL" = 0 ] && touch /var/lock/subsys/sshd-ext
echo
}
stop()
{
echo -n $"Stopping $prog: "
if [ -n "`pidfileofproc $SSHD`" ] ; then
killproc $SSHD -TERM
else
failure $"Stopping $prog"
fi
RETVAL=$?
[ "$RETVAL" = 0 ] && rm -f /var/lock/subsys/sshd-ext
echo
}
reload()
{
echo -n $"Reloading $prog: "
if [ -n "`pidfileofproc $SSHD`" ] ; then
killproc $SSHD -HUP
else
failure $"Reloading $prog"
fi
RETVAL=$?
echo
}
case "$1" in
start)
start
;;
stop)
stop
;;
restart)
stop
start
;;
reload)
reload
;;
condrestart)
if [ -f /var/lock/subsys/sshd-ext] ; then
do_restart_sanity_check
if [ "$RETVAL" = 0 ] ; then
stop
# avoid race
sleep 3
start
fi
fi
;;
status)
status $SSHD
RETVAL=$?
;;
*)
echo $"Usage: $0
{start|stop|restart|reload|condrestart|status}"
RETVAL=1
esac
exit $RETVAL
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