I read this article a few years ago and thoroughly enjoyed it, but I've had trouble solving Default Permit in practice. Does anyone know of a free software operating system that white-lists its software (say by having the white-list be tied to the package manager) without having to do a lot of tinkering/configuring? I know you can do it with certain Linux add-ons that provide mandatory access control like SELinux and grsecurity, but it always seems like they introduce problems that you then have to troubleshoot for hours before your system is usable again. Bonus points for if this distro uses ASLR, W^X, and other countermeasures to avoid violating the security policy through code injection.