From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: [PATCH 12/27] x86/msr: Restrict MSR access when the kernel is locked down Date: Fri, 20 Oct 2017 19:09:39 +0100 Message-ID: <20171020190939.569cedd2@alans-desktop> References: <150842463163.7923.11081723749106843698.stgit@warthog.procyon.org.uk> <150842472452.7923.2592278090192179002.stgit@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <150842472452.7923.2592278090192179002.stgit@warthog.procyon.org.uk> Sender: owner-linux-security-module@vger.kernel.org To: David Howells Cc: linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, matthew.garrett@nebula.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, jforbes@redhat.com List-Id: linux-efi@vger.kernel.org On Thu, 19 Oct 2017 15:52:04 +0100 David Howells wrote: > From: Matthew Garrett > > 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