I had an authorization log (/var/lib/auth.log) was filling up with errors related to a missing pam_winbind.so library:
May 1 01:25:01 servername CRON: pam_unix(cron:session): session opened for user root by (uid=0) May 1 01:25:01 servername CRON: pam_unix(cron:session): session closed for user root May 1 01:25:16 servername auth: PAM unable to dlopen(/lib/security/pam_winbind.so): /lib/security/pam_winbind.so: cannot open shared object file: No such file or directory May 1 01:25:16 servername auth: PAM adding faulty module: /lib/security/pam_winbind.so
…over and over. I tried upgrading winbind to the latest version in the Debian stable repositories. I installed libpam-winbind (2:3.6.6-6+deb7u3 for both). Neither of those actions fixed the problem. The library, pam_winbind.so, was not present in /lib/security.
After reading this thread:
I found that the library was simply in the wrong location. It was the only file under /lib/powerpc-linux-gnu/security/. This machine is a powerpc. Other architectures will have a different architecture name in the /lib directory.
The simple solution was to make a symlink under at /lib/security/pam_winbind.so that points to the existing library at /lib/powerpc-linux-gnu/security/pam_winbind.so:
sudo ln -s /lib/powerpc-linux-gnu/security/pam_winbind.so /lib/security/pam_winbind.so
No more errors in the auth.log.