Bug 18205

i have installed 7.0 clean with a custom server installation, including 
openssh. everything functions correctly except:

when restarting sshd like this:

/etc/rc.d/init.d/sshd restart (or condrestart, or stop start)

the existing ssh session remains alive, but no new sessions can be 
started. in addition, restarting a second time causes the existing session 
to also be dropped.

this has the following effect:

no access can be gained to the server until sshd is restarted from the 
console (assuming telnet is blocked)

i have no idea whether it is possible, but could someone use this to cause 
sshd to restart - denying access to the sysadm - in order to hide their 
activities or as a DOS attack?



below is the /etc/ssh/sshd_config file:

# This is ssh server systemwide configuration file.

Port 22
Protocol 2,1
ListenAddress 0.0.0.0
#ListenAddress ::
HostKey /etc/ssh/ssh_host_key
ServerKeyBits 768
LoginGraceTime 600
KeyRegenerationInterval 3600
PermitRootLogin no
#
# Don't read ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# Uncomment if you don't trust ~/.ssh/known_hosts for 
RhostsRSAAuthentication
#IgnoreUserKnownHosts yes
StrictModes yes
X11Forwarding no
X11DisplayOffset 10
PrintMotd yes
KeepAlive yes

# Logging
SyslogFacility AUTH
LogLevel INFO
#obsoletes QuietMode and FascistLogging

RhostsAuthentication no
#
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
#
RSAAuthentication yes

# To disable tunneled clear text passwords, change to no here!
PasswordAuthentication no
PermitEmptyPasswords no
# Uncomment to disable s/key passwords
#SkeyAuthentication no

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

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

CheckMail no
UseLogin no

Subsystem       sftp    /usr/local/sbin/sftpd