I can no longer su root

slackaddict · 10-18-2005, 01:36 PM

Like the subject says, I can no longer "su root". I'm running Slackware 10.1 and it goes like this...

Code:

slackaddict@slackbox:~$ su
Password:
Sorry.
slackaddict@slackbox:~$

I'm entering the password correctly and if I CTRL+ALT+F6 to a terminal I can login directly as root with no problems. Also, if I click on "Administrator Mode" in the KDE Control Center it keeps telling me the password I enter is wrong, but I know its right.

I think this may have something to do with recently installing Ubuntu as a dual boot. Ubuntu handles the root account differently and it may have changed some config file somewhere.

Any ideas?

XavierP · 10-18-2005, 01:57 PM

Check your keyboard settings. Are you using "special characters" in the password?

slackaddict · 10-18-2005, 05:26 PM

Good suggestion XavierP, unfortunately I'm still stuck.

I thought you were on to something because I know in KDE you can switch between multiple keyboard layouts, which would explain why I could login in a text terminal but not in X. However if I type the password in an editor it shows up correctly every time, including symbols such as '$' and '!'.

I think this is a case of my user account no longer being allowed to su, even if the password is correct. I don't know if thats possible but it seems reasonable, disabling su for general users would be a good security move in some cases.

I'll keep trying....

cs-cam · 10-18-2005, 07:03 PM

In the terminal (not KDE), login as your user and then try to su. If it still complains about the password being wrong then I'd suggest that somehow you've managed to remove yourself from the wheel group. This would also have removed your permission to use su

slackaddict · 10-19-2005, 04:55 AM

aaah.. I think we are on the right track

I can confirm that I am unable to su even in a terminal. But, I am also still listed in the wheel group...

Code:

slackaddict@slackbox:~$ groups
slackaddict wheel floppy audio video cdrom games users

I even created a new user (and added him to the wheel group), but this user cannot su either.

What I have discovered is that "sudo" still seems to work okay...

Code:

slackaddict@slackbox:~$ ls -l /etc/lilo.conf
-rw-r--r--  1 root root 590 2005-10-19 11:40 /etc/lilo.conf
slackaddict@slackbox:~$ sudo vi /etc/lilo.conf
reading /etc/lilo.conf

wrote /etc/lilo.conf, 39 lines, 590 chars

Very strange. I'll keep trying....

slackaddict · 10-19-2005, 05:18 AM

Success... kind of

I just reinstalled the slackware packages "shadow" (which contains su) and "kdebase" (which contains kdesu). I can now su as normal!

I am still interested if anyone has any ideas about why this happened in the first place.

trickykid · 10-19-2005, 05:35 AM

The wheel group has nothing to do with su'ing.

As for your problem, what did you do right before you couldn't su? Did you upgrade or install any packages? Reinstalling the shadow package most likely fixed and reverted a configuration file for you possibly.

But you should really setup sudo and using it instead of plain ol su. It's more secure as you don't need to use root's password and you won't be logging in directly as root when you do su as root.

cs-cam · 10-19-2005, 08:11 AM

Quote:

The wheel group has nothing to do with su'ing.

Ha, I thought it did but after checking with Google, I guess it's just a BSD (and Gentoo) thing...

slackaddict · 10-20-2005, 01:46 AM

trickykid, you're right about using sudo instead of su. I usually do, I only noticed the su problem when I was trying to access "Administrator Mode" in the KDE Control Center.

As for what caused the problem in the first place, I can only think it has something to do with installing Ubuntu on a separate partition. I don't see how, because the only partitions that were shared were /home and /usr/local, but I don't have any other ideas

Also, I have seen an article about using pam to restrict which users can use su. I don't know anything about pam but if some distros come set up like this by default then you may need to be in the wheel group to su.

Anyway, the system is running beautifully again now, thanks guys.

trickykid · 10-20-2005, 02:28 AM

Quote:

Originally posted by slackaddict
trickykid, you're right about using sudo instead of su. I usually do, I only noticed the su problem when I was trying to access "Administrator Mode" in the KDE Control Center.

As for what caused the problem in the first place, I can only think it has something to do with installing Ubuntu on a separate partition. I don't see how, because the only partitions that were shared were /home and /usr/local, but I don't have any other ideas

Also, I have seen an article about using pam to restrict which users can use su. I don't know anything about pam but if some distros come set up like this by default then you may need to be in the wheel group to su.

Anyway, the system is running beautifully again now, thanks guys.

Installing another OS on the same computer would not affect su in any way shape or form. The only thing that can occur when installing multiple OS's on the same computers is screwing up the MBR or boot loader.

T2F · 10-20-2005, 06:03 PM

Something probably happened to the /etc/suauth file.

man suauth

Regards,
Bill