[Bug 1179344] Re: ssh doesn't get pty; says "inappropriate ioctl for device"

[Todd A. Jacobs]

@cjwatson, you're correct that the bugs seem related. For example:

    May 13 09:45:42 emu sshd[12679]: Accepted publickey for codegnome from 192.168.1.127 port 50803 ssh2
    May 13 09:45:42 emu sshd[12679]: pam_unix(sshd:session): session opened for user codegnome by (uid=0)
    May 13 09:45:42 emu systemd-logind[1778]: New session c20 of user codegnome.
    May 13 09:45:42 emu sshd[12679]: fatal: monitor_read: unsupported request: 144
    May 13 09:45:42 emu sshd[12679]: pam_unix(sshd:session): session closed for user codegnome
    May 13 09:45:42 emu sshd[12822]: fatal: mm_request_send: write: Broken pipe

However, I think this bug report describes aspects of the problem that
are not in the other ticket, which does not address any of the TERM,
pty,  or login shell issues directly. In other words, while I think they
are related I don't think they are duplicates.

I am subscribed to the other bug too, so I will test again when the
other bug has been closed and see if it closes this one as well. Thanks
for pointing out the other bug!

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https://bugs.launchpad.net/bugs/1179344

Title:
  ssh doesn't get pty; says "inappropriate ioctl for device"

Status in “openssh” package in Ubuntu:
  Confirmed

Bug description:
  ## Versions

      $ lsb_release -rd
      Description:    Ubuntu Saucy Salamander (development branch)
      Release:        13.10

      $ uname -a
      Linux emu 3.9.0-1-generic #5-Ubuntu SMP Wed May 8 20:52:16 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

      $ apt-show-versions -a openssh-server
      openssh-server 1:6.2p1-2 install ok installed
      openssh-server 1:6.2p1-2 saucy us.archive.ubuntu.com

  ## Problem

  After a recent (accidental) upgrade to 13.10, recent updates to the
  kernel seem to make inbound SSH connections problematic. Specifically,
  the remote client is unable to connect to a login shell. This was
  extremely difficult to diagnose, because all the client says is:

      $ ssh emu 
      Last login: Sun May 12 21:35:35 2013 from goldendelicious
      Shared connection to 192.168.1.127 closed.
      Connection to 192.168.1.127 closed by remote host.

  Even with the verbose flag turned on (e.g. `-v` and `-vvv`) all you
  see is that you connect, then get "debug1: Exit status -1" for no
  discernable reason. The rest of the verbose output is completely
  uninteresting However, there are other ways to debug this, as shown
  below.

  ### SSH connection results in dumb terminal

      $ echo $TERM
      xterm-256color

      $ ssh emu /bin/echo \$TERM
      dumb

  As you can see, openssh does not use the correct TERM environment
  variable. However, manually setting TERM (e.g. `export TERM=vt100`)
  doesn't solve the problem, because you don't actually have a pty. See
  next section.

  ### Non-login shells work...sort of

      $ ssh emu /bin/bash -i
      bash: cannot set terminal process group (-1): Inappropriate ioctl for device
      bash: no job control in this shell
      emu:~$  echo $TERM
      echodumb
       $TERM
      emu:~$ tty
      tty
      not a tty

  As you can see here, openssh is unable to open a tty or pty. If you
  try to force it with `-t` or `-tt`, then it returns to the previous
  behavior of simply closing the connection without explanation.

  ## Temporary Work-Around

  One way to work around this problem is to use X-Forwarding to launch
  an xterm as a login shell. For example:

      $ ssh emu xterm -e 'bash -l'

  This works, assigns a pty, and otherwise results in a usable remote
  connection, but is certainly not a substitute for having a working
  non-X11 shell.

  ## Expected Behavior

  1. OpenSSH should receive a pty on the remote host.
  2. The TERM variable should be properly propogated.
  3. There should be a more obvious way to debug this; openssh reports NOTHING of use in this situation, even with maximum verbosity.

  ProblemType: Bug
  DistroRelease: Ubuntu 13.10
  Package: openssh-server 1:6.2p1-2
  ProcVersionSignature: Ubuntu 3.9.0-1.5-generic 3.9.1
  Uname: Linux 3.9.0-1-generic x86_64
  NonfreeKernelModules: nvidia
  ApportVersion: 2.10-0ubuntu3
  Architecture: amd64
  Date: Sun May 12 21:40:41 2013
  EcryptfsInUse: Yes
  InstallationDate: Installed on 2011-10-15 (575 days ago)
  InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
  MarkForUpload: True
  SourcePackage: openssh
  UpgradeStatus: Upgraded to saucy on 2013-05-06 (6 days ago)

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