I was doing some maintenance via root account over ssh after several months of inattention. I shutdown, after startup I can't log in to root account at tty or via ssh. Fortunately, sudo works to perform root actions through my user account. There's nothing special about the install. Its out-of-the-box, so to speak. root uses local authentication. I first tried changing the root password. The password change was successful, because I was also able to authenticate against the root account with: authconfig --test, which asks for root password outside of sudo/su.Reset permissions and owner/groups with rpm -a --setperms coreutilsPAM debug on pam_succeed_if.so. Here is the last borked session using pam debug flag:Jul 27 18:29:18 mrwizard sshd[2054]: Server listening on 0.0.0.0 port 22.Jul 27 18:29:18 mrwizard sshd[2054]: Server listening on :: port 22.Jul 27 18:32:51 mrwizard login: pam_succeed_if(login:session): 'service' resolves to 'login'Jul 27 18:32:51 mrwizard login: pam_succeed_if(login:session): requirement service in crond not met by user rootJul 27 18:32:51 mrwizard login: pam_unix(login:session): session opened for user root by LOGIN(uid=0)Jul 27 18:32:51 mrwizard login: ROOT LOGIN ON tty1Jul 27 18:32:52 mrwizard login: pam_succeed_if(login:session): 'service' resolves to 'login'Jul 27 18:32:52 mrwizard login: pam_succeed_if(login:session): requirement service in crond not met by user rootJul 27 18:32:52 mrwizard login: pam_unix(login:session): session closed for user rootJul 27 18:32:56 mrwizard login: pam_succeed_if(login:session): 'service' resolves to 'login'Jul 27 18:32:56 mrwizard login: pam_succeed_if(login:session): requirement service in crond not met by user rootrequirement service in crond seems normal TMI// As requested:Jul 27 18:29:27 mrwizard crond[2271]: (CRON) STARTUP (1.4.4)Jul 27 18:29:27 mrwizard crond[2271]: (CRON) INFO (RANDOM_DELAY will be scaled with factor 34% if used.)Jul 27 18:29:27 mrwizard crond[2271]: (CRON) INFO (running with inotify support)Jul 27 18:30:01 mrwizard CROND[2479]: (root) CMD (/usr/lib/sa/sa1 1 1)Jul 27 18:40:01 mrwizard CROND[5021]: (root) CMD (/usr/lib/sa/sa1 1 1)Jul 27 18:50:01 mrwizard CROND[7503]: (root) CMD (/usr/lib/sa/sa1 1 1)Jul 27 19:00:01 mrwizard CROND[10985]: (root) CMD (/usr/lib/sa/sa1 1 1)Jul 27 19:01:01 mrwizard CROND[11232]: (root) CMD (run-parts /etc/cron.hourly)Jul 27 19:01:01 mrwizard run-parts(/etc/cron.hourly)[11232]: starting 0anacronJul 27 19:01:01 mrwizard run-parts(/etc/cron.hourly)[11241]: finished 0anacronJul 27 19:10:01 mrwizard CROND[13425]: (root) CMD (/usr/lib/sa/sa1 1 1)Jul 27 19:20:01 mrwizard CROND[16899]: (root) CMD (/usr/lib/sa/sa1 1 1)Jul 27 19:30:01 mrwizard CROND[19324]: (root) CMD (/usr/lib/sa/sa1 1 1)Jul 27 19:40:01 mrwizard CROND[21719]: (root) CMD (/usr/lib/sa/sa1 1 1)Jul 28 18:14:45 mrwizard crond[2317]: (CRON) STARTUP (1.4.4)Jul 28 18:14:45 mrwizard crond[2317]: (CRON) INFO (RANDOM_DELAY will be scaled with factor 45% if used.)Jul 28 18:14:45 mrwizard crond[2317]: (CRON) INFO (running with inotify support)$ cat /etc/pam.d/crond # The PAM configuration file for the cron daemon# No PAM authentication called, auth modules not neededaccount    required   pam_access.soaccount    include    password-authsession    required   pam_loginuid.sosession    include    password-authauth       include    password-auth
What processes on CentOS6/RHEL regulates user login but not password itself?
login;pam;consolekit