ssh no longer works after upgrade from ubuntu 10.10 server to 11.04
 

Hi,
I upgraded to ubuntu server 11.04 a while back, and ever since then the ssh does not work. For example, if I try to log in it seems to take my credentials but immediately kicks me off. Further looking in the log shows pam_open_session() module is unknown. I do remember it asking to upgrade some /etc/security/something.conf file, so maybe that has something to do with it. I have no clue how to fix this, and for now I'm stuck using my host's out of band access (and no sftp or scp either). Any help is appreciated.
Thanks,
-Michael.

Moved: This thread is more suitable in Ubuntu and has been moved accordingly to help your question get the exposure it deserves.

From the pam_open_session manpage:
I don't think you have the full picture. Provide more information on how you are logging in? Are you trying to log into you regular user account? Do you use public key authentication?

Try logging in using the -vv option to provide better debugging messages on the client side. It will show messages from both the client and the server.

Hi,
To answer your questions:
I am using simply user/password authentication, and I am logging into a user account I could access since I created the server (until this upgrade).
I will try using the option you mention (if I can figure out how to get it working :)) and let you know what happens.
Thanks,
-Michael.

Hi,
As requested, here is the output from ssh -vv (with output sensored to protect my server :)).
Hope someone can help.
-Michael.

The SSH connection is being established. You are even getting the 'issue' message. Could you check the kernel messages at the same time on the server? A failure with PAM may post a message there. Also look in /etc/security/ and the PAM config files for files with .new at the end which sometimes indicate recommended changes after a package is updated, but the old one may contain lines you need to retain.

I had a problem with SSH after installing a new version of openSuSE. I needed to precede the a path in sshd_config with %h/ that I hadn't need before.

Entering a portion of your error message exactly, inside double quotes, in a Google search may return results useful in finding a solution.

Hi,
I looked in many places, including /var/log/syslog, /var/log/kern.log, /var/log/auth.log, and a couple others. i found nothing more noticable than I found before, namely that pam says "pam_open_session(), module is unknown")
Thanks,
-Michael.

I looked in the manpage for "pam_open_session". It is a function and not a module. You might want to check your pam configuration and make sure you have all your files. Could you post your common-session and sshd files in /etc/pam.d/?

Start with the sshd file. Make sure you have the .so files mentioned in /etc/security.
For example:
In this example, the pam modules pam_nologin.so, pam_loginuid.so and pam_lastlog.so are used. The common-auth, common-account, common-password and common-session files are pam config files in /etc/pam.d/ that may also use different pam modules.

Hi,
If you mean that the *.so files mentioned in /etc/pam.d/sshd should be in the directory /etc/security/, there are absolutely no *.so files there. I also looked in /lib/security, and there was only pam_mysql.so in there.
Thanks,
-Michael.

The pam .so libraries are in /lib/security or /lib64/security.

Hi,
I looked in /lib/security and all that is there with a .so extension is pam-mysql.so. I don't see anything listed in sshd there. As for lib64/security, it doesn't even exist (I am running a 32 version of ubuntu, however).
Hth,
-Michael.

Check your package manager to see what files should be supplied with the base PAM packages. The pam_unix2 module should be supplied. It's one that is always used to log in as far as I know.