How does SELinux apply to NTP in FC4?
Well, you don't need SELinux. NTPD as shipped runs by default as user 'ntp' (AFAIR), and can be chrooted as well. OpenNTPD takes the functional separation a bit further. About the only thing a "bad packet" can cause is adjusting your clock.. whether that's bad or not is debatable.
-- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings