Re: Zenbleed

In reply to: Shawn Webb : "Re: Zenbleed"
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From: Jung-uk Kim <jkim_at_FreeBSD.org>
Date: Thu, 27 Jul 2023 16:09:53 UTC

On 23. 7. 26., 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.
> 
> Note that this code is simply Tavis' original PoC, just modified
> enough to get it to build on FreeBSD and OpenBSD.

FYI, the attached patch should reduce the diff and do the right thing.

Jung-uk Kim