Automatic kerberos ticket initialization on login

Question

I'm using ksshaskpass to add my password protected keys into ssh-agent upon logging into KDE, is there something similar for kerberos?

Answer 1

I would look into using pam-krb5.

On Debian and Ubuntu, it should be apt-get install libpam-krb5.

The PAM configuration would look something like:

auth required pam_unix.so
auth optional pam_krb5.so try_first_pass

or

auth required pam_unix.so
auth optional pam_krb5.so use_first_pass   

in /etc/pam.d/common-auth.

It takes the password you used to authenticate locally, e.g. the password in /etc/shadow, and then tries to use the same one as your Kerberos password.

If your Kerberos password is the same as your system password, you don't need to type it again.

If your Kerberos password is different from your system password, what happens depends on whether you used try_first_pass or use_first_pass:

• try_first_pass will ask you for your Kerberos password
• use_first_pass won't ask you, but you'll have to run kinit yourself later

Note that this probably makes ksshaskpass redundant too, because you can also have:

auth required pam_unix.so
auth optional pam_ssh.so try_first_pass
auth optional pam_krb5.so try_first_pass

On Debian and Ubuntu, that requires installing libpam-ssh.

Answer 2

Normally, Kerberos would be integrated with PAM pam_krb5.so. It will attempt to acquire a Kerberos ticket based on your username and the password you supply. It can also use that to verify whether you are allowed to login, but that can be set to ignore if you just want the ticket. It needs to be added as both an auth and a session module, probably also password if you plan to keep your Kerberos password in sync with your desktop. If you plan to use Kerberos for verifying a user's login, you should also setup your keytab file at /etc/krb5.keytab with a key for host/[email protected] replace hostname and example.com as appropriate for your environment.