OpenSSH hanging

[Darren Tucker]

On 7/10/11 9:58 AM, Henry Barber wrote:
>     I'm having some strange behaviour from OpenSSH
>     It presents itself when using the "ssh -t" / pseudo terminal.
>     We are using this feature to update the wtmp and it is working fine on
>     SuSE and RH, but our AIX hosts are getting hung. The first attempt is
>     usually successful, but eventually, the session is hung and the CRTL-Z
>     does not put the process into background.
>     The ssh -v output
>     OpenSSH_5.4p1, OpenSSL 0.9.8m 25 Feb 2010

This could happen with old versions of OpenSSH: they did not correctly 
handle the case where pty allocation failed.

This was fixed in 5.6.  From http://www.openssh.com/txt/release-5.6:

  Kill channel when pty allocation requests fail. Fixed stuck client
    if the server refuses pty allocation (bz#1698)

-- 
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
     Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.