Re: [PATCH 12/27] x86/msr: Restrict MSR access when the kernel is locked down

[Alan Cox]

On Thu, 19 Oct 2017 15:52:04 +0100
David Howells <dhowells@xxxxxxxxxx> wrote:

> From: Matthew Garrett <matthew.garrett@xxxxxxxxxx>
> 
> Writing to MSRs should not be allowed if the kernel is locked down, since
> it could lead to execution of arbitrary code in kernel mode.  Based on a
> patch by Kees Cook.

There are a load of standard tools that use this so I think you are going
to need a whitelist. Can you at least log *which* MSR in the failing case
so a whitelist can be built over time ?

Alan