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

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Date:   Sun, 12 Feb 2023 23:17:42 +0000 (GMT)
From:   "Maciej W. Rozycki" <macro@...am.me.uk>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>
cc:     "Jason A. Donenfeld" <Jason@...c4.com>,
        Kees Cook <keescook@...omium.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [PING][PATCH v3] x86: Use `get_random_u8' for kernel stack offset
 randomization

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@angie.orcam.me.uk/>.

  Maciej