Harden access to the /proc filesystem in Linux.
This script restricts read access to some files in the Linux /proc filesystem that may
enable attacks or leak private information.
/proc should be mounted with the hidepid=2 or hidepid=invisible option to prevent
user processes from being visible to other users.
The kernel option CONFIG_SECURITY_DMESG_RESTRICT prevents kernel messages from being
visible to unprivileged users.
This script was written by Hanno Böck.