[SOLVED] Permissions Messed Up

[memaster3]

I was using sudo chmod -r /usr/* and it was supposed to have a folder specified after it, and it changed up the permissions on everything in the bin folder. I got it back to normal enough to use the system, the only thing left is the sudo command and the su command. When I try sudo, it says:

jon-Tuxbox:~$ sudo
sudo: must be setuid root

and when I try su, it says:

jon-Tuxbox:~$ su
Password: 
setgid: Operation not permitted

Can you help me fix these things? Also, when I try to install applications from Ubuntu Software Center, the authentication dialog briefly pops up and shakes left to right, then it disappears. It doesn't let me click it or hit enter.

(Sorry, I know the username is supposed to have an [at] symbol instead of a hyphen, but the forum does not let me post the [at] symbol yet.)

[reed9]

Boot into recovery mode as described here.

Do

chown root:root /usr/bin/sudo
chmod 4755 /usr/bin/sudo

Ubuntu doesn't use su by default.

[memaster3]

Thanks! It fixed it. And I use su for anything in which I will be using root for a long time. I already had it set it up, but just in case, i tried sudo passwd, and it didn't fix it either.