sudo: setuid must be root

Question

I changed the permissions of my /usr directory to 777 by mistake and now my system give this error whenever I try to use sudo:

sudo: setuid must be root

How do I fix this issue?

should be on serverfault, but i'll tell you now your best bet is to re install OS - all the setuid and setgid bits will be gone, short of finding out what all of those are and running chmod +sS you'll want to reinstall — tobyodavies, Jan 27, 2011 at 6:18
i had the same problem 2 weeks ago. reinstalling is the only solution. — theTuxRacer, Feb 16, 2011 at 10:03

João Pinto · Accepted Answer · 2011-01-27 13:42:42Z

3

Based on your error, you didn't simply changed the permissions of /usr to 777, you did it recursively which is a more serious and problematic change.

Unless you have backups of your system directories, your best option is just to reinstall.

answered Jan 27, 2011 at 13:42

João Pinto

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With the caveat that you could manually reset every file of every sub-directory to the right setting by manually comparing it to a good Ubuntu install.
– djeikyb
Apr 17, 2011 at 18:46

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Bhanu Krishnan · Accepted Answer · 2011-05-17 05:29:05Z

0

Go to recovery console (reboot, and chose recovery console ) and type

chown root:root /usr/bin/sudo

then

chmod 4755 /usr/bin/sudo

then

reboot

answered May 17, 2011 at 5:29

Bhanu Krishnan

1012 bronze badges

1

It'll work for sudo only, but other binaries are affected as well and are likely to cause issues too.
– Lekensteyn
May 17, 2011 at 8:42

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2 Answers 2