I noticed the following message from syslog:
Jan 6 16:34:20 myserver login: FAILED LOGIN SESSION FROM
xxx.edu FOR (null), Error in service module
The '(null)' looks suspiciously to be a printout of a null string.
This also appears to happen with RH 6.1:
Jan 17 11:02:22 mikrosopht PAM_pwdb: authentication failure; LOGIN(uid=0)
-> valankar for login service
Jan 17 11:02:23 mikrosopht login: FAILED LOGIN 1 FROM (null) FOR valankar,
Jan 17 11:02:26 mikrosopht PAM_pwdb: (login) session opened for user
valankar by LOGIN(uid=0)
This is normal behaviour when logging in from a local terminal. It is a NULL
pointer and that's perfectly OK with printf...