I'm sick of typing the root password every time I want to su - on Fedora to become the root user. I know how to allow sudo access without a password, but I don't want to use sudo, I want to be able to just type su - and become root.
I couldn't find a good answer for this on Google, so I read the man pages of pam (Pluggable Authentication Modules) until I figured it out.
In the file /etc/pam.d/su put this as the second line:
auth sufficient pam_permit.so
This is incredibly insecure as it lets literally anyone at all with a login become root.
To restrict this just to your username, use this line instead, replace the yourusername with your actual username:
auth sufficient pam_succeed_if.so use_uid user = yourusername
You can also restrict this to a group, here the group allowedpeople can su without a password:
auth sufficient pam_succeed_if.so use_uid user ingroup allowedpeople