Cfrgtkky

TLDR: I am running Ubuntu 18.04 with i3 and I messed up my permissions. Whenever I run a command with sudo, I get this error message, sudo: /usr/local/bin/sudo must be owned by uid 0 and have the setuid bit set. I am trying to figure out if I need to fully re-install Ubuntu or if this can be fixed in a less drastic way.

What had happened was: I was trying to upgrade my npm version with nvm and the nvm command was not being recognized. I followed this stackoverflow post's instructions https://stackoverflow.com/questions/21215059/cant-use-nvm-from-root-or-sudo to copy the version of node I had active via nvm into the /usr/local. I ran the below. (Yes, I realize now that I should have investigated this series of commands before running them.)

n=$(which node); 

n=${n%/bin/node}; 

chmod -R 755 $n/bin/*; 

sudo cp -r $n/{bin,lib,share} /usr/local

I then got tons of errors saying
chmod: changing permissions of '/usr/bin/*': Operation not permitted

After that I ran sudo nvm install-latest-npm and got the same error as I had before, sudo: nvm: command not found.

Then I tried running another command with sudo, and got the error sudo: /usr/local/bin/sudo must be owned by uid 0 and have the setuid bit set. I now get this error whenever I run anything with sudo.

I think this problem was caused by me running chmod -R 755 $n/bin/*; but I'm confused because the error message said permissions for /usr/bin were not changed.

I have a two-part question:
1) What caused this error? Am I correct that it was caused by the chmod -R command?
2) Can I fix this without completely reinstalling ubuntu? If so, how?

For context, I already read these two questions sudo: /usr/lib/sudo/sudoers.so must be owned by uid 0 and this /usr/bin/sudo must be owned by uid 0 and have the setuid bit set. However, I am not sure if the advice from the first question's answer applies to this situation, because the error message I receive is not referring specifically to /usr/lib/sudo/sudoers.so.

Thanks for reading!

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

1. 
   

   Check the current owner and permissions with ls -l /usr/bin/sudo. It should similar to:

   
   
   

   -rwsr-xr-x 1 root root 157192 2018-08-23 10:36:40 /usr/bin/sudo

   
   



2. Run pkexec bash in a terminal to get a shell with root permissions.



3. 
   

   Fix ownership of the file:

   
   
   

   chown root:root /usr/bin/sudo
   
   

   
   


4. 
   

   Set the setuid bit:

   
   
   

   chmod u+s /usr/bin/sudo
   
   

   
   



5. sudo should now be available for you to make further repairs.