passwd/shadow or group/gshadow mismatch?

Question

I'm running RHEL 5. When using the GUI System>Administration>Users and Groups, I get the error:

The user database cannot be read. This problem is most likely caused by a mismatch between /etc/passwd and /etc/shadow or /etc/group and /etc/gshadow. The program will exit now.

Some research showed that I need to use vipw and vigr respectively to find an inconsistency between these two sets, which I did - to make it easy I copied each from [vipw | vigr] to an excel file and did =exact(%1, %2). There are no inconsistencies.

What gives?

// Edits //

sudo pwck -r yeilds several users without home directories:

user adm: directory /var/adm does not exist
user news: directory /etc/news does not exist
user uucp: directory /var/spool/uucp does not exist
user gopher: directory /var/gopher does not exist
user ftp: directory /var/ftp does not exist
user pcap: directory /var/arpwatch does not exist
user sabayon: directory /home/sabayon does not exist
user oprofile: directory /home/oprofile does not exist
user avahi-autoipd: directory /var/lib/avahi-autoipd does not exist

I assume this is normal for service accounts.

However, sudo grpck -r yields some interesting output (sanitized):

no matching group file entry in /etc/gshadow
add group 'g0' in /etc/gshadow ?No
'u1' is a member of the 'g1' group in /etc/group but not in /etc/gshadow
'u2' is a member of the 'g1' group in /etc/group but not in /etc/gshadow
'u3' is a member of the 'g1' group in /etc/group but not in /etc/gshadow
no matching group file entry in /etc/group
delete line 'users:::'? No
no matching group file entry in /etc/group
delete line 'u4:!::'? No
no matching group file entry in /etc/group
delete line 'u1:!::'? No
no matching group file entry in /etc/group
delete line 'u2:!::'? No
no matching group file entry in /etc/group
delete line 'u3:!::'? No
no matching group file entry in /etc/group
delete line 'u5:!::'? No
no matching group file entry in /etc/group
delete line 'u6:!::'? No
no matching group file entry in /etc/group
delete line 'u7:!::'? No
grpck: no changes

So, clearly we found some problems. It looks to me that automated repair would be destructive in some cases.

Solution

Why would you use Excel?

cut -d: -f1 /etc/passwd | sort > p.out
sudo cut -d: -f1 /etc/shadow | sort > s.out
diff p.out s.out
rm p.out s.out

Or in Bash:

diff <(cut -d: -f1 /etc/passwd | sort) <(sudo cut -d: -f1 /etc/shadow | sort)

and you can do the same kind of thing for /etc/group and /etc/gshadow.

You need to run GUI System>Administration>Users and Groups with elevated permissions. Is it asking you for a password?

Comments

[Dennis Williamson]

It looks like you found your problem.

[weak]

Because it's what I know - Your way is definitely slick, but I needed a way to quickly and systematically find differences or prove that there weren't any. For me, Excel was that way. I almost facepalmed when I read your elevated permissions bit. I opened a console, switched to root via su, and then ran /usr/bin/system-config-users. Same error as before.

[Dennis Williamson]

@Tony: run sudo pwck -r and sudo grpck -r to show you any errors in these files. What do they say (summarize the result or add it to your original question).

[weak]

I answered yes to all of the delete requests from grpck, and now the GUI works. Hopefully users don't call :)