Re: Zenbleed

From: Shawn Webb <shawn.webb_at_hardenedbsd.org>
Date: Thu, 27 Jul 2023 17:48:29 UTC
On Thu, Jul 27, 2023 at 01:38:09PM -0400, Jung-uk Kim wrote:
> On 23. 7. 27., Jung-uk Kim wrote:
> > On 23. 7. 27., mike tancsa wrote:
> > > On 7/26/2023 5:46 PM, Shawn Webb wrote:
> > > > On Wed, Jul 26, 2023 at 08:34:56PM +0000, 0x1eef wrote:
> > > > > Hello,
> > > > > 
> > > > > I was curious if there are plans to apply the "chicken bit"
> > > > > workaround for the Ryzen line of processors. A firmware
> > > > > update is not scheduled to be released until Nov or Dec
> > > > > at the earliest. Thanks.
> > > > For those that would like to test if their systems are affected, this
> > > > proof-of-concept was reported to work on at least one system:
> > > > 
> > > > https://git.hardenedbsd.org/shawn.webb/zenbleed/-/tree/shawn.webb/bsd/main
> > > > 
> > > > Building it depends on gmake and nasm. You'll want to be on the
> > > > shawn.webb/bsd/main branch.
> > > 
> > > Thanks for that. Is there a way to compile on RELENG_12 or is it 13
> > > only ?
> > > 
> > > % gmake
> > > cc -O0 -ggdb3 -march=znver2   -c -o pattern.o pattern.c
> > > pattern.c:15:10: fatal error: 'sys/sysinfo.h' file not found
> > > #include <sys/sysinfo.h>
> > >           ^~~~~~~~~~~~~~~
> > > 1 error generated.
> > > gmake: *** [<builtin>: pattern.o] Error 1
> > 
> > I guess you checked out a wrong branch.  Please see the attached minimal
> > patch I made for FreeBSD.  I think it will work on any supported FreeBSD
> > branches.  Note the original exploit is available from here:
> > 
> > https://lock.cmpxchg8b.com/files/zenbleed-v5.tar.gz

Awesome! Thanks! I'll incorporate that patch later today.

Thanks again,

-- 
Shawn Webb
Cofounder / Security Engineer
HardenedBSD

https://git.hardenedbsd.org/hardenedbsd/pubkeys/-/raw/master/Shawn_Webb/03A4CBEBB82EA5A67D9F3853FF2E67A277F8E1FA.pub.asc