Bug#350208: sshd can't keep track of which DISPLAYs are in use

[Terran Melconian <terran@consistent.org>]

> This seems to be working as expected here (same version of ssh on a
> fully up-to-date sarge box), regardless of the X11UseLocalhost setting. 
> If you'd be so kind as to post a copy of /etc/ssh/sshd_config, I'll

Certainly; thanks for looking at this.

In addition to the configuration files, here is a transcript of the
problem:

    terran@things$ ssh localhost
    Linux There-Are-Many-Things 2.6.15 #4 PREEMPT Sun Jan 15 21:15:06 EST
    2006 i686 GNU/Linux
    [ snip motd ]

    terran@things$ echo $DISPLAY
    There-Are-Many-Things:12.0

    terran@things$ ~^Z [suspend ssh]

    [1]+  Stopped                 ssh localhost

    terran@things$ ssh localhost
    Linux There-Are-Many-Things 2.6.15 #4 PREEMPT Sun Jan 15 21:15:06 EST
    2006 i686 GNU/Linux
    [ snip motd ]

    terran@things$ echo $DISPLAY
    There-Are-Many-Things:12.0

Of course, the second time we should be getting :13.0. (it doesn't
matter that I'm connecting from the same machine; when I connect from
a remote machine I get the same problem)

-------- /etc/ssh/sshd_config

# Package generated configuration file
# See the sshd(8) manpage for defails

# What ports, IPs and protocols we listen for
Port 22
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0
Protocol 1,2
# HostKeys for protocol version 1
HostKey /etc/ssh/ssh_host_key
# HostKeys for protocol version 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 768

# Logging
SyslogFacility AUTH
LogLevel INFO

# Authentication:
LoginGraceTime 600
PermitRootLogin yes
StrictModes yes

RSAAuthentication yes
PubkeyAuthentication yes
#AuthorizedKeysFile	%h/.ssh/authorized_keys

# rhosts authentication should not be used
#RhostsAuthentication no
# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
#IgnoreUserKnownHosts yes

# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no

# Uncomment to disable s/key passwords 
#ChallengeResponseAuthentication no

# To disable tunneled clear text passwords, change to no here!
PasswordAuthentication yes

# Use PAM authentication via keyboard-interactive so PAM modules can
# properly interface with the user
#PAMAuthenticationViaKbdInt yes

# To change Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#AFSTokenPassing no
#KerberosTicketCleanup no

# Kerberos TGT Passing does only work with the AFS kaserver
#KerberosTgtPassing yes

X11Forwarding yes
X11DisplayOffset 10
PrintMotd no
#PrintLastLog no
KeepAlive yes
#UseLogin no
X11UseLocalhost no


#MaxStartups 10:30:60
#Banner /etc/issue.net
#ReverseMappingCheck yes

Subsystem	sftp	/usr/lib/sftp-server

#UsePrivilegeSeparation yes

UsePAM yes

-------- end /etc/ssh/sshd_config

-------- /etc/pam.d/ssh

# PAM configuration for the Secure Shell service

# Disallow non-root logins when /etc/nologin exists.
auth       required     pam_nologin.so

# Read environment variables from /etc/environment and
# /etc/security/pam_env.conf.
auth       required     pam_env.so # [1]

# Standard Un*x authentication.
@include common-auth

# Standard Un*x authorization.
@include common-account

# Standard Un*x session setup and teardown.
@include common-session

# Print the message of the day upon successful login.
session    optional     pam_motd.so # [1]

# Print the status of the user's mailbox upon successful login.
session    optional     pam_mail.so standard noenv # [1]

# Set up user limits from /etc/security/limits.conf.
session    required     pam_limits.so

# Standard Un*x password updating.
@include common-password

-------- end /etc/pam.d/ssh