I have an Amazon EC2 instance. I can login just fine, but neither "su" nor "sudo" work now (they worked fine previously):

• "su" requests a password, but I login using ssh keys, and I don't think the root user even has a password.

• "sudo <anything>" does this:

sudo: /etc/sudoers is owned by uid 222, should be 0 
sudo: no valid sudoers sources found, quitting 

I probably did "chown ec2-user /etc/sudoers" (or, more likely "chown -R ec2-user /etc" because I was sick of rsync failing), so this is my fault.

How do I recover? I stopped the instance and tried the "View/Change User Data" option on the AWS EC2 console, but this didn't help.

EDIT: I realize I could kill this instance and create a new one, but was hoping to avoid something that extreme.