Error:
sudo: /usr/bin/sudo must be owned by uid 0 and have the setuid bit set.
Fixed:
reboot and login to recovery,
login to root prompt,
mount -o remount,rw /
mount –all
chown root:root /usr/bin/sudo
chmod 4755 /usr/bin/sudo
ls -l /usr/bin/sudo
chmod 644 /etc/passwd
chmod u+s /bin/su
reboot