Messages in this thread | | | Date | Mon, 8 Apr 2013 15:55:10 -0700 | Subject | Re: [PATCH] x86: make IDT read-only | From | Kees Cook <> |
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On Mon, Apr 8, 2013 at 3:47 PM, H. Peter Anvin <hpa@zytor.com> wrote: > On 04/08/2013 03:43 PM, Kees Cook wrote: >> This makes the IDT unconditionally read-only. This primarily removes >> the IDT from being a target for arbitrary memory write attacks. It has >> an added benefit of also not leaking (via the "sidt" instruction) the >> kernel base offset, if it has been relocated. >> >> Signed-off-by: Kees Cook <keescook@chromium.org> >> Cc: Eric Northup <digitaleric@google.com> > > This isn't quite what this patch does, though, right? There is still a > writable IDT mapping at all times, which is different from a true > readonly IDT, no?
Ah, I guess that's true. I suppose I should say it makes the memory seen at the "sidt" location read-only. Can we make them both read-only?
-Kees
-- Kees Cook Chrome OS Security
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