Chrooted OpenSSH for Windows (rssh sftp cygwin)

["John M. L." <john at recaffeinated dot com>]

I've been trying to implement an sftp server using OpenSSH for Windows
(http://sshwindows.sourceforge.net).  I haven't found much recent discussion
on th topic of running OpenSSH in a chrooted jail on cygwin, but the
following messages from a year ago have shed some light on the topic:

http://archive.erdelynet.com/ssh-l/2003-10/msg00057.php

http://www.cygwin.com/ml/cygwin/2003-08/msg00738.html

http://cygwin.com/ml/cygwin/2003-07/msg01500.html

I almost have the system running on Windows 2000 Server.  Using the ssh
server without chroot is fine.  However, when I try to connect using the
chrooted sftp shell it automatically disconnects the user.  Using WinSCP3 to
connect returns at cryptic error code 127 and a command line sftp just dies
silently with no explanation.

Here's my current login shell script for users:

#!/bin/sh
#echo Parameters: "$@" >> /home/sshlogin.log
if [ "$*" != "-c /usr/sbin/sftp-server" ]; then
   echo "Sorry, sftp only!"
   exit 1
fi

#without chroot works!
exec /bin/sh -i "$@"

#with chroot no such luck
#chroot /cygdrive/c/StudentsShare exec /bin/sh -i "$@"


I'm assuming part of the problem may be the required files for the /bin/sh
call are not inside the chroot jail /cygdrive/c/StudentsShare.  If this is
the case, I would like to know if anyone could let me know what files should
be included.  At first I got Cygwin dll errors stating that cyg*.* could not
be found. They stopped once I moved the files into the jail and/or fixed
environment path variables.

I have two log files using sshd -d -d -d for high debug output.  They can be
found here:

Chrooted log:
http://john.isosceles7.com/files/login_chroot.txt

Un Chrooted log
http://john.isosceles7.com/files/login_nochroot.txt

The debug is cryptic, but if I think the error in the chroot is around line
116.  Here's an excerpt of this piece


Chrooted log (lines 112-126):

subsystem request for sftp
debug1: subsystem: exec() /usr/sbin/sftp-server
debug2: fd 10 setting O_NONBLOCK
debug2: fd 9 setting O_NONBLOCK
debug2: channel 0: read<=0 rfd 10 len 0
debug1: Received SIGCHLD.
debug2: channel 0: read failed
debug2: channel 0: close_read
debug2: channel 0: input open -> drain
debug2: channel 0: ibuf empty
debug2: channel 0: send eof
debug2: channel 0: input drain -> closed
debug2: notify_done: reading
debug1: session_by_pid: pid 1364
debug1: session_exit_message: session 0 channel 0 pid 1364

Un Chrooted log (lines 112-126):

subsystem request for sftp
debug1: subsystem: exec() /usr/sbin/sftp-server
debug2: fd 10 setting O_NONBLOCK
debug2: fd 9 setting O_NONBLOCK
debug2: channel 0: rcvd eof
debug2: channel 0: output open -> drain
debug2: channel 0: obuf empty
debug2: channel 0: close_write
debug2: channel 0: output drain -> closed
debug1: Received SIGCHLD.
debug1: session_by_pid: pid 1368
debug1: session_exit_message: session 0 channel 0 pid 1368
debug2: channel 0: request exit-status
debug1: session_exit_message: release channel 0
debug1: session_close: session 0 pid 1368


Any help on my problem would be appreciated!  Of course if any other
background information is helpful I will gladly contribute!


... An additional note:  The new cygwin dll 1.5.12-1 source includes
wordexp.h which was a problem that prohibited using rssh
(http://www.pizzashack.org) instead of chrooting openssh.  Does anyone know
how this will affect rssh?



Thanks,

John M Lauck



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