These linux improvments and pitbull are two totally different things though. Pitbull aims to implement full B1 compatibilty into Solaris, while the work the nsa has done just aims to implement a security policy(which you can read at their site) that improves overall security on linux.
It's interesting to see 3 major "secure linux" efforts, all with different goals we have http://www.wirex.com/ ImmunixOS, linux+Stackguard/formatguard/subdomain/cryptomark/etc, reasonably mature (I have a beta, works quite well). http://www.argussystems.com/ Pitbull, B1 shiz, I'm not to enamoured with this oprange book stuff (buzzword compliance) http://www.nsa.gov/selinux/ NSA, access controls, who did what when, ok, let's shoot 'em in the head. Basically it's like comparing apples to oranges to kiwi fruit. Some people hate kiwi but love apples. OTOH if you want to make kiwi fruit pie.....
-miah -- less talk more clue.
-Kurt