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RE: Unable to run sshd under a domain sshd_server account [SOLVED]
On Mon, 12 May 2008, Schutter, Thomas A. wrote:
> > -----Original Message-----
> > From: Igor Peshansky
> > Sent: Monday, May 12, 2008 4:30 PM
> > To: Schutter, Thomas A.
> > Subject: RE: Unable to run sshd under a domain sshd_server account
> > On Mon, 12 May 2008, Schutter, Thomas A. wrote:
> > > > -----Original Message-----
> > > > From: Schutter, Thomas A.
> > > > Sent: Monday, May 12, 2008 9:52 AM
> > > > To: 'cygwin@XXXXXX.XXX'
> > <http://cygwin.com/acronyms/#PCYMTNQREAIYR>.
> > > > Subject: Unable to run sshd under a domain sshd_server account
> > > >
> > > > I am having problems setting up sshd to run under a domain
> > sshd_server
> > > > account instead of a local sshd_server account.
> > > > [snip]
> > > > But when I login via ssh:
> > > > $ echo $USER
> > > > tschutter
> > > > $ echo $USERNAME
> > > > sshd_server
> > Yes -- Windows does not understand user impersonation and does not
> > allow real user switching. So what sshd does is invoke processes with
> > the appropriate token privileges for the user it's impersonating,
> > while updating internal Cygwin data structures, but still running as
> > sshd_server. So Cygwin sees the right user (in its internal state),
> > but Windows processes, of course, don't.
> Interesting. I suspected this, but this is the first time that I have
> seen this explicitly stated.
Well, at least Windows processes don't understand the Cygwin notion of
effective UID, which is why $USERNAME and $USER don't match (one is set by
Windows, and the other by a Cygwin process -- bash).
> > > > The application event log has this error message:
> > > > The description for Event ID ( 0 ) in Source ( sshd ) cannot be
> > > > found. The local computer may not have the necessary registry
> > > > information or message DLL files to display messages from a remote
> > > > computer. You may be able to use the /AUXSOURCE= flag to retrieve
> > > > this description; see Help and Support for details. The following
> > > > information is part of the event: sshd: PID 2068: service `sshd'
> > > > failed: signal 11 raised.
> > Oops -- a segfault. This is definitely a bug somewhere -- no matter
> > what, sshd should not segfault.
Those problems are usually very hard to reproduce. If you're set up to
build a debug version of sshd and run it under gdb to reproduce the fault,
a stack backtrace would be helpful.
> > > In the other thread, Larry Hall pointed me to the FAQ
> > > http://cygwin.com/faq/faq-nochunks.html#faq.using.shares. One of the
> > > suggestions was to "provide your password to a net use command". I
> > > was unable to make that work, because "net use" never asks for my
> > > password:
> > > $ net use \\other\f$
> > > System error 67 has occurred.
> > >
> > > The network name cannot be found.
> > See "net help use":
> > The syntax of this command is:
> > NET USE
> > [devicename | *] [\\computername\sharename[\volume] [password | *]]
> > ...
> > password Is the password needed to access the shared
> > resource.
> > * Produces a prompt for the password. The password is
> > not displayed when you type it at the password
> > prompt.
> > So, you need to type "net use '\\other\f$' \*" (note the
> > '*'), and it'll prompt you for the password.
> OK. So on a console cygwin shell:
> $ net use '\\other\f$'
> The command completed successfully.
> But when run in a ssh shell (using the sshd_server account):
> $ net use '\\other\f$' \*
> Type the password for \\zoom\f$: System error 1326 has occurred.
> Logon failure: unknown user name or bad password.
Umm, yes. Sorry. I forgot that sshd runs in a pty, which is a pipe as
far as Windows is concerned. And 'net' cannot read the password from a
> Same thing happens with:
> $ net use '\\other\f$' '*'
> $ net use '\\other\f$' "*"
Actually supplying the password instead of '*' should work.
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