Re: [PING][PATCH v3] x86: Use `get_random_u8' for kernel stack offset randomization

From: Thomas Gleixner
Date: Mon Feb 13 2023 - 14:02:28 EST


On Sun, Feb 12 2023 at 23:17, Maciej W. Rozycki wrote:
> On Mon, 30 Jan 2023, Maciej W. Rozycki wrote:
>
>> For x86 kernel stack offset randomization uses the RDTSC instruction,
>> which according to H. Peter Anvin is not a secure source of entropy:
>>
>> "RDTSC isn't a super fast instruction either, but what is *way* more
>> significant is that this use of RDTSC is NOT safe: in certain power states
>> it may very well be that stone number of lower bits of TSC contain no
>> entropy at all."
>
> Ping for:
> <https://lore.kernel.org/all/alpine.DEB.2.21.2301302011150.55843@xxxxxxxxxxxxxxxxx/>.

I'm waiting for you to address Peter Anvins feedback. You also cite him
w/o providing a link to the conversation, so any context is missing.

Thanks,

tglx