Password not accepted when attempting to logging back in after locking the screen

[Henrik Steensland]

Feisty up to date.
gnome-screensaver 2.18.0-0ubuntu1
gdm 2.18.0-0ubuntu4
xorg 1:7.2-0ubuntu9

When I lock the screen and attempt to log back in the password is not accepted.
This is similar to the following bugs, but I don't see it as duplicates since it doesn't freeze and I don't use KDE (#26175) and don't have an iceauthority file (#4737).

It appeared after the latest feisty upgrade. I have not had this problem with feisty before.

[Henrik Steensland (henrik-steensland)]

Problem located.

$ cat /var/log/auth.log
new unix_chkpwd[15399]: check pass; user unknown
new gnome-screensaver-dialog: (pam_unix) authentication failure; logname= uid=1000 euid=1000 tty=:0.0 ruser= rhost= user=dahen

libpam-modules: 0.79-4ubuntu2

$ cat /etc/var/pam.d/gnome-screensaver
@include common-auth

$ cat /etc/var/pam.d/common-auth
auth required pam_unix.so nullok_secure

$ ls -l /sbin/unix_chkpwd
-rwxr-sr-x 1 root shadow 18128 2006-12-20 18:59 /sbin/unix_chkpwd

$ ls -l /etc/shadow
-rw-r----- 1 root root 1038 2007-04-02 08:18 /etc/shadow

unix_chkpwd is setGID but /etc/shadow does not belong to the shadow group.

The solution is therefore to change group on /etc/shadow or to setUID /sbin/unix_chkpwd

[Henrik Steensland (henrik-steensland)]

It seems I had gotten root.root permissons all over my /etc folder. My fault.
Closing this bug.