Cygwin 1.7.9 + OpenSSH 5.9p1-1 Domain Service Account error "Bad file descriptor" after authentication [SOLVED]

[William Voyek <william dot voyek at gmail dot com>]

In order to run a SSH server I installed Cygwin 1.7.9 + OpenSSH
5.9p1-1 on Windows 7 Enterprise SP1. I read the FAQ entry for setting
up sshd in a domain located at:
http://cygwin.com/faq-nochunks.html#faq.using.sshd-in-domain

After completing the install I proceeded to create the cyg_server
domain user account, a privileged service account group, and the
necessary Group Policy with the SeTcbPrivilege,
SeCreateTokenPrivilege, SeAssignPrimaryTokenPrivilege,
SeServiceLogonRight, SeDenyInteractiveLogonRight,
SeDenyRemoteInteractiveLogonRight privileges set for my service group.
I then created the /etc/group and /etc/passwd files including the
cyg_server account and ran the ssh-host-config script. I answered
"yes" to all questions except for the "Do you want to use a different
name?" to which I answered "no".

I then issued "net start sshd" and the CYGWIN sshd service started
successfully. To test I then issued "ssh localhost" and I was greeted
with a password prompt. After entering the proper password I was then
greeted with "Connection to localhost closed by remote host."

After doing some initial checking on the system I verified that the
service was running, that it was successfully authenticating my
account, but when creating the tty for the remote shell sshd was
throwing an error:

chown(/dev/tty1, 500, 513) failed: Bad file descriptor

I started searching the Cygwin mailing lists and discovered the following posts:

http://cygwin.com/ml/cygwin/2010-11/msg00199.html
http://cygwin.com/ml/cygwin/2011-03/msg00125.html
http://cygwin.com/ml/cygwin/2011-08/msg00016.html
http://cygwin.com/ml/cygwin/2011-08/msg00182.html

Unfortunately in the posts it appeared that no one had posted a
solution to the issue.

After uninstalling and reinstalling Cygwin countless times, a clean
Windows 7 install, and lots of hair pulling it appears I have
discovered what the issue was (at least in my case):

cyg_server must be a member of the *Local* Administrators group on the
machine running the service. It was not enough that the user account
is a member of the Administrators group for the domain.

I just wanted to post this in case someone else runs into this issue like I did.

William

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