I cannot execute any command using sudo. I get this error:
pi@raspberrypi:~ $ sudo apt-get update
sudo: /etc/sudoers is world writable
sudo: no valid sudoers sources found, quitting
sudo: unable to initialize policy plugin
pi@raspberrypi:~ $
It does not matter what command I try to execute using sudo, I always get the same error.
This is what happens when the permissions on /etc get messed up. There is a forum post which shows methods to fix this:
Restore from your latest backup
Re-image the SD card and start again
Add "init=/bin/sh" to the end of cmdline.txt to get a root recovery shell, mount the "/" partition and try and fix the permissions. Most of them should be 644 (-rw-r--r--) for files and 755 (drwxr-xr-x) for directories with owner root:root, but there are a few that are more restrictive. /etc/sudoers and anything under /etc/sudoers.d should be 640 (-rw-r-----). That is probably very important. The /etc/sudoers.d directory itself is 755 like all the other directories.
