Showing posts with label kdm. Show all posts
Showing posts with label kdm. Show all posts

Nov 16, 2009

Bypassing disabled accounts with KDM

So the most common way of disabling an account in a unix system is changing the users shell in /etc/passwd to /bin/false or /sbin/nologin. However, I've discovered on Arch Linux that if I do this only shell login's are disabled, I was still able to log the user in with gui via kdm. I also tried using usermod --expiredate 1. this was not effective either however. the only way I found to lock the account from kdm login was to do a passwd -l accountname, which only locks password authentication. This means key and token authentication should still work. My real concern is that if the user was set to login without a password that it would still be bypass-able. My personal opinion is that I shouldn't have to do more than 1 thing to disable a user account in a 100% effective manner. Currently Arch Linux (and maybe more) fails at this. I'll post a fix later as I investigate further.

Bugs I filed are at kde and Arch Linux

EDIT: expire date worked... just not immediately, very odd.

EDIT: Here's a proper /etc/pam.d/kde

#%PAM-1.0
auth        required    pam_nologin.so
auth        required    pam_unix.so nullok
auth        required    pam_shells.so
auth required pam_tally.so onerr=succeedfile=/var/log/faillog
account     required    pam_access.so
account     required    pam_time.so
account     required    pam_unix.so
password    required    pam_unix.so
session     required    pam_unix.so
session     required    pam_env.so
session     required    pam_limits.so