Greetings:
I've just attempted to upgrade from openssh-2.1.1p1 to openssh-2.1.1p3
and I'm having problems with the server component. My system runs RedHat
Linux 6.2 (x86 version) with all currently released updates applied.
The sshd daemon is being spawned by xinetd with the -i option and worked
fine with the p1 level release.
Now, when a remote client attempts to connect to the daemon, the
authentication challenge occurs and is processed and the session is
logged in, but then it's logged out again immediately before any user
input is allowed.
>From the remote client end, it looks like the following:
[blp at anotherhost ~]# ssh -l dummy somehost.example.com
dummy at somehost.example.com's password:
Last login: Sat Jul 15 14:05:52 2000 from anotherhost.example.com
Connection to somehost.example.com closed.
I attempted to run sshd with the -d option in order to get a better feel
for what's happening, but the problem did not occur in this mode. I then
just fired up sshd in stand-alone mode (no options) and the problem did
not occur in this situation either, thus my assertion that the problem
is confined to the inetd mode. My first attempts were using the binary
rpm release from the openssh site, but after grabbing the source rpm
and building it myself the results were the same. My sshd_config file
is pretty much all defaults, with the exception of the loglevel change
mentioned below.
Since the -d option didn't help, I changed the loglevel setting in
/etc/ssh/sshd_config to DEBUG and caught the output of one of the failed
connection attempts. The sshd output below matches the client side login
attempt above.
Jul 15 14:06:06 somehost xinetd[27138]: START: ssh from=some.ip.address
Jul 15 14:06:06 somehost sshd[27621]: debug: Seeding random number generator
Jul 15 14:06:06 somehost sshd[27621]: debug: inetd sockets after dupping: 5, 6
Jul 15 14:06:06 somehost sshd[27621]: Generating 768 bit RSA key.
Jul 15 14:06:06 somehost sshd[27621]: debug: Seeding random number generator
Jul 15 14:06:07 somehost sshd[27621]: debug: Seeding random number generator
Jul 15 14:06:07 somehost sshd[27621]: RSA key generation complete.
Jul 15 14:06:07 somehost sshd[27621]: Connection from some.ip.address port 2011
Jul 15 14:06:07 somehost sshd[27621]: debug: Client protocol version 1.5; client
software version OpenSSH_2.1.1
Jul 15 14:06:07 somehost sshd[27621]: debug: Local version string
SSH-1.99-OpenSSH_2.1.1
Jul 15 14:06:07 somehost sshd[27621]: debug: Sent 768 bit public key and 1024
bit host key.
Jul 15 14:06:07 somehost sshd[27621]: debug: Encryption type: 3des
Jul 15 14:06:07 somehost sshd[27621]: debug: Received session key; encryption
turned on.
Jul 15 14:06:07 somehost sshd[27621]: debug: Installing crc compensation attack
detector.
Jul 15 14:06:07 somehost sshd[27621]: debug: Starting up PAM with username
"dummy"
Jul 15 14:06:07 somehost sshd[27621]: debug: Attempting authentication for
dummy.
Jul 15 14:06:09 somehost sshd[27621]: debug: PAM Password authentication
accepted for user "dummy"
Jul 15 14:06:09 somehost sshd[27621]: Accepted password for dummy from
some.ip.address port 2011
Jul 15 14:06:09 somehost sshd[27621]: debug: PAM setting rhost to
"anotherhost.example.com"
Jul 15 14:06:09 somehost sshd[27621]: debug: session_new: init
Jul 15 14:06:09 somehost sshd[27621]: debug: session_new: session 0
Jul 15 14:06:09 somehost sshd[27621]: debug: Allocating pty.
Jul 15 14:06:09 somehost sshd[27621]: debug: PAM setting tty to
"/dev/pts/8"
Jul 15 14:06:09 somehost PAM_pwdb[27621]: (sshd) session opened for user dummy
by (uid=0)
Jul 15 14:06:09 somehost sshd[27621]: debug: PAM establishing creds
Jul 15 14:06:09 somehost sshd[27621]: debug: Entering interactive session.
Jul 15 14:06:09 somehost sshd[27621]: debug: no set_nonblock for tty fd 0
Jul 15 14:06:09 somehost sshd[27622]: debug: Setting controlling tty using
TIOCSCTTY.
Jul 15 14:06:09 somehost sshd[27621]: debug: no set_nonblock for tty fd 7
Jul 15 14:06:09 somehost sshd[27621]: debug: server_init_dispatch_13
Jul 15 14:06:09 somehost sshd[27621]: debug: server_init_dispatch_15
Jul 15 14:06:09 somehost sshd[27621]: debug: tvp!=NULL kid 0 mili 10
Jul 15 14:06:09 somehost sshd[27621]: debug: End of interactive session; stdin
0, stdout (read 65, sent 65), stderr 0 bytes.
Jul 15 14:06:09 somehost sshd[27621]: debug: Command exited with status 0.
Jul 15 14:06:09 somehost sshd[27621]: debug: Received exit confirmation.
Jul 15 14:06:09 somehost sshd[27621]: debug: session_pty_cleanup: session 0
release /dev/pts/8
Jul 15 14:06:09 somehost sshd[27621]: syslogin_perform_logout: logout() returned
an error
Jul 15 14:06:09 somehost sshd[27621]: Closing connection to some.ip.address
Jul 15 14:06:09 somehost PAM_pwdb[27621]: (sshd) session closed for user dummy
I'm not on the list, so if any more information is needed please contact
me directly via email. Thanks for looking into this, and for the
great work the entire team has done in making a free ssh implementation
available.
Ben
--
Ben L. Perkins -=- Houston, TX, USA
