Bug#631708: openssh-server: ssh hangs on exit if X11 forwarding has been used

[Steinar Bang <sb@dod.no>]

Package: openssh-server
Version: 1:5.5p1-6
Severity: normal

When I start an ssh session to my debian testing ("Wheezy") computer,
with "ssh -Y machinename", and start emacs, then exit emacs, and then
then log out, the ssh session hangs on logout.

This happens both when the client is my Ubuntu 10.10 netbook
(openssh-client 1:5.5p1-4ubuntu5), and from a Windows 7 laptop with
Xming, using putty as the SSH client (I don't have the Windows 7
laptop at hand so I am unsure of the exact version numbers).

The problem does not occur if I don't start any X11 applications
during the session.  Then the logout from the ssh session, does not
hang.

The problem does not occur if the machine I connect to is debian
stable.  If try to reproduce the issue with one of my debian stable
machines, ie. log in with "ssh -Y", start an X11 application, stop the
X11 application, and then log out, the session terminates normally.

openssh-server on debian stable is currently at version 1:5.5p1-6.

-- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (650, 'testing'), (600, 'unstable')
Architecture: i386 (i686)

Kernel: Linux 2.6.39-2-686-pae (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages openssh-server depends on:
ii  adduser                 3.113            add and remove users and groups
ii  debconf [debconf-2.0]   1.5.39           Debian configuration management sy
ii  dpkg                    1.16.0.3         Debian package management system
ii  libc6                   2.13-7           Embedded GNU C Library: Shared lib
ii  libcomerr2              1.41.12-4stable1 common error description library
ii  libgssapi-krb5-2        1.9.1+dfsg-1     MIT Kerberos runtime libraries - k
ii  libkrb5-3               1.9.1+dfsg-1     MIT Kerberos runtime libraries
ii  libpam-modules          1.1.3-1          Pluggable Authentication Modules f
ii  libpam-runtime          1.1.3-1          Runtime support for the PAM librar
ii  libpam0g                1.1.3-1          Pluggable Authentication Modules l
ii  libselinux1             2.0.98-1+b1      SELinux runtime shared libraries
ii  libssl0.9.8             0.9.8o-7         SSL shared libraries
ii  libwrap0                7.6.q-19         Wietse Venema's TCP wrappers libra
ii  lsb-base                3.2-27           Linux Standard Base 3.2 init scrip
ii  openssh-blacklist       0.4.1            list of default blacklisted OpenSS
ii  openssh-client          1:5.5p1-6        secure shell (SSH) client, for sec
ii  procps                  1:3.2.8-10       /proc file system utilities
ii  zlib1g                  1:1.2.3.4.dfsg-3 compression library - runtime

Versions of packages openssh-server recommends:
ii  openssh-blacklist-extra       0.4.1      list of non-default blacklisted Op
ii  xauth                         1:1.0.6-1  X authentication utility

Versions of packages openssh-server suggests:
pn  molly-guard                   <none>     (no description available)
pn  rssh                          <none>     (no description available)
pn  ssh-askpass                   <none>     (no description available)
pn  ufw                           <none>     (no description available)

-- debconf information:
  ssh/vulnerable_host_keys:
  ssh/new_config: true
* ssh/use_old_init_script: true
  ssh/encrypted_host_key_but_no_keygen:
  ssh/disable_cr_auth: false