Linux 权限 suid

http://www.linuxquestions.org/questions/linux-newbie-8/sudo-must-be-setuid-root-891420/

Once check whether you've sudo access or not, 

Code:

example% su root
example% sudo -l -U <your-username>

It will list all commands that you can run as sudo.
If you have enough privileges, then do SUID on /usr/bin/sudo, as:

Code:

example% chmod u+s /usr/bin/sudo

It should work then! Good luck!