Ubuntu server sudo: Must be setuid root perfect solution.

1.StartPerform the recovery mode by shift or ESC

2. Select the root command line mode.

3. Execute

# Mount-O remount, RW/

This is very important because many of the materials found on the Internet are incomplete and cannot be restored successfully.

Because the recovery mode is mounted in read-only mode by default, if this statement is not executed, it will be reported

4. Execute

# Chown root: Root/usr/bin/sudo
# Chmod 4755/usr/bin/sudo

5. Run after restart

Sudo ls

Report

# Sudo:/usr/lib/sudo/sudoers. So must be owned by UID 0
# Sudo: Fatal error, unable to load plugins

6. Restart to restore the root mode.

Run

# Chown root/usr/lib/sudo/sudoers. So

Restart to solve the problem.