sudo must be owned by uid 0 and have the setuid bit set

Question

I am trying to run the following command:

$ echo "My username is: `whoami`"
My username is: d
$ sudo chown -R `whoami` /usr/local/lib/node_modules
sudo: /usr/bin/sudo must be owned by uid 0 and have the setuid bit set

I don't understand what the problem is because root is uid 0:

$ id -u root
0

And the setuid seem fine:

$ ls -l /usr/bin/sudo
-rwxr-xr-x 1 4755 root 155008 Feb 10  2014 /usr/bin/sudo

Solution 1

The Setuid bit is not set. If it were, the permissions would have an s instead of the first x:

$ ls -l /usr/bin/sudo 
-rwsr-xr-x 1 root root 155008 Feb 11  2014 /usr/bin/sudo

Try using pkexec to set it correctly:

pkexec chmod a=rx,u+ws /usr/bin/sudo

Though I doubt that's the only problem you are going to have.

Solution 2

Login with root (su) and run the following command

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

Comments

[Mark Williams]

Cool, I didn't know that one - could have saved me grief the other day!

[Fabby]

Oh! Look! I can upvote twice!

[user2201789]

i got this "pkexec must be setuid root" what should i do?

[muru]

@user12158726 then you're much worse off and will need to reboot and use recovery shell, or use a live USB, to fix permissions.