Messages in this thread | | | Date | Tue, 26 May 2020 09:20:31 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v1] x86: Pin cr4 FSGSBASE |
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On Tue, May 26, 2020 at 08:48:35AM -0700, Andi Kleen wrote: > On Tue, May 26, 2020 at 08:56:18AM +0200, Greg KH wrote: > > On Mon, May 25, 2020 at 10:28:48PM -0700, Andi Kleen wrote: > > > + if (val & X86_CR4_FSGSBASE) { > > > + WARN_ONCE(1, "CR4 unexpectedly set FSGSBASE!?\n"); > > > > What about those systems that panic-on-warn? > > I assume they're ok with "panic on root hole"
Exactly. :) The pinning infrastructure is pretty small; will that just get backported? (Also, we can probably rework the pinning to avoid the special-casing and use a mask/value pair to notice a bit getting turned _on_ as well...)
-- Kees Cook
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