Re: pseudo-tty doesn't get allocated

From: David Svanberg (davidkristofer_at_hotmail.com)
Date: 10/20/04 

Date: 20 Oct 2004 01:53:02 -0700

davidkristofer@hotmail.com (David Svanberg) wrote in message news:<3e4a06a.0410180017.3aa62903@posting.google.com>...
> davidkristofer@hotmail.com (David Svanberg) wrote in message news:<3e4a06a.0410150827.7cd4f611@posting.google.com>...
> > Dear comp.security.ssh,
> >
> > Let me first mention that I'm a ssh newbie. I was so happy when I
> > recenly could setup a publickey authentication! Please, STOP THAT
> > LAUGHING... ;)
> >
> > What I'm trying to do is to connect a server using the ssh -t -t
> > command in order to force a pseudo-tty from a java application (using
> > Runtime.getRuntime()). This works just fine towards one host but not
> > to all sshd's. Note that I don't have root permissions so I'm unable
> > to read the server side logs. It's really bad - but that's life.
> >
> > Anyway, the authentication seems to work just perfectly and the output
> > of the client looks just fine until suddenly this appears on stderr:
> >
> > tcgetattr: Inappropriate ioctl for device
> >
> > And then it seems to me that the requested pseudo-tty can't be setup:
> >
> > debug2: callback start
> > debug2: ssh_session2_setup: id 0
> > debug2: channel 0: request pty-req
> > debug3: tty_make_modes: ospeed 0
> > debug3: tty_make_modes: ispeed 0
> > debug3: tty_make_modes: 1 0
> > debug3: tty_make_modes: 2 0
> > debug3: tty_make_modes: 3 0
> > debug3: tty_make_modes: 4 0
> > debug3: tty_make_modes: 5 0
> > debug3: tty_make_modes: 6 0
> > debug3: tty_make_modes: 7 0
> > debug3: tty_make_modes: 8 0
> > debug3: tty_make_modes: 9 0
> > debug3: tty_make_modes: 10 0
> > debug3: tty_make_modes: 12 0
> > debug3: tty_make_modes: 13 0
> > debug3: tty_make_modes: 14 0
> > debug3: tty_make_modes: 18 0
> > debug3: tty_make_modes: 30 0
> > debug3: tty_make_modes: 31 0
> > debug3: tty_make_modes: 32 0
> > debug3: tty_make_modes: 33 0
> > debug3: tty_make_modes: 34 0
> > debug3: tty_make_modes: 35 0
> > debug3: tty_make_modes: 36 0
> > debug3: tty_make_modes: 37 0
> > debug3: tty_make_modes: 38 0
> > debug3: tty_make_modes: 39 0
> > debug3: tty_make_modes: 40 0
> > debug3: tty_make_modes: 41 0
> > debug3: tty_make_modes: 50 0
> > debug3: tty_make_modes: 51 0
> > debug3: tty_make_modes: 53 0
> >
> > etc, tty_make* is set to zero. And finally I suddenly get kicked out
> > receving an EOF:
> >
> > debug2: callback done
> > debug2: channel 0: open confirm rwindow 0 rmax 32768
> > debug2: channel 0: rcvd adjust 131072
> > debug2: channel 0: rcvd eof
> >
> > Do you guys have any ideas about what to do? I run OpenSSH_3.7.1.p2 on
> > both client and server (client Cygwin, server Solaris). Normal command
> > line login works just fine. Thankful for any hints.
> >
> > Yours Sincerly,
> > David Svanberg
>
> OK, I've got no answers yet. I'm not sure I've described this clearly
> enough or if I'm posting to the wrong group. What I've found is that
> /dev/ptmx exists on the Solaris server side (this seems to be some
> kind of virtual tty allocator device or something). In the ssh client
> application this seems to be the first file to use when openpty() is
> called. I've seen a discussion thread about "Bug#35704: libc6: ssh
> fails to allocate a pseudo tty" on
> http://lists.debian.org/debian-glibc/1999/04/msg00021.html, but I'm
> not sure this is what I'm experience. These guys are talking about
> recompiling the kernel as if it was a daily task - and I've do not
> even have root permissions... Help!
>
> Best Regards,
> David Svanberg

Still no answer. I've found out that the problem is that various
sshd's handles tty speed=0 diffently. I've tested this by setting:

stty 0

On a SSH Secure Shell 2.3.0 (non-commercial version) on SunOS 5.7
Generic_106541-33 sun4u sparc SUNW,Ultra-5_10 the communication works
fine, but under OpenSSH_3.7.1p2 on SunOS 5.9 Generic_112233-12 sun4u
sparc SUNW,Netra-240 it hangs as mentioned above.

Well guys, is this a bug somewhere or what?

Yours Sincerly,
David Svanberg