lkml.org 
[lkml]   [2020]   [Jul]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 2/4] KVM: x86: Introduce paravirt feature CR0/CR4 pinning
From
Date
On 7/9/20 9:07 AM, Andy Lutomirski wrote:
> On Thu, Jul 9, 2020 at 8:56 AM Dave Hansen <dave.hansen@intel.com> wrote:
>> On 7/9/20 8:44 AM, Andersen, John wrote:
>>> Bits which are allowed to be pinned default to WP for CR0 and SMEP,
>>> SMAP, and UMIP for CR4.
>> I think it also makes sense to have FSGSBASE in this set.
>>
>> I know it hasn't been tested, but I think we should do the legwork to
>> test it. If not in this set, can we agree that it's a logical next step?
> I have no objection to pinning FSGSBASE, but is there a clear
> description of the threat model that this whole series is meant to
> address? The idea is to provide a degree of protection against an
> attacker who is able to convince a guest kernel to write something
> inappropriate to CR4, right? How realistic is this?

If a quick search can find this:

> https://googleprojectzero.blogspot.com/2017/05/exploiting-linux-kernel-via-packet.html

I'd pretty confident that the guys doing actual bad things have it in
their toolbox too.

\
 
 \ /
  Last update: 2020-07-09 18:22    [W:0.061 / U:0.780 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site