On Tue, 2013-02-12 at 22:33 -0800, H. Peter Anvin wrote: > That is just batshit crazy. If you have CAP_SYS_RAWIO you can do iopl() > which means you can reprogram your northbridge, at which point you most > definitely *can* modify the running kernel.
Well right, that's the point of this patchset - it adds some extra permission checks to some of the existing CAP_SYS_RAWIO checks. CAP_SYS_RAWIO hasn't meant "I can perform arbitrary pio and mmio" for years - it means "I can do things that might maybe break something somehow". So sure, removing CAP_SYS_RAWIO would give us basically all the security we want in a secure boot environment, but it would also block things that we *want* to work.
