Messages in this thread | | | Date | Wed, 13 Feb 2013 09:20:46 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86: Lock down MSR writing in secure boot |
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On 02/12/2013 10:41 PM, Matthew Garrett wrote: > 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. >
So, let 's see...
Problem:
Someone adds SYS_CAP_RAWIO to some places it definitely does not belong.
Solution:
Break all the *appropriate* (as defined)uses of SYS_CAP_RAWIO?
What the heck?
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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