Increase the security of your Linux kernel with the grsecurity patch

Wikipedia has a pretty good explanation of what grsecurity and PaX do, but in a nutshell, here's what this set of patches buys you:

non-executable stack
address-space randomization
role-based access control
chroot hardening
enhanced auditing

If you're looking for a quick way of downloading the latest stable Linux kernel with the grsecurity patch already applied, clone this git repository (which can be browsed here):

git-clone http://git.catalyst.net.nz/linux-2.6.24-grsec.git

I also maintain an RSS feed (well, an Atom feed actually) keeping track of the latest grsecurity and PaX test patches:

http://feeds.feedburner.com/grsecurity

Finally, make sure you run paxtest to make sure that the protections offered by grsecurity and PaX are properly enabled.