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 <alpine.DEB.2.21.2302140447190.6368@angie.orcam.me.uk> <DDFBF35E-D837-4CDC-8EF8-2CBF75C77901@zytor.com>
In-Reply-To: <DDFBF35E-D837-4CDC-8EF8-2CBF75C77901@zytor.com>
From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
Date:   Wed, 22 Feb 2023 17:44:08 +0100
Message-ID: <CAHmME9r4DnQDkx0VSzfuYDyUhNOHy0d3XBzF+hipU7EVy0raKA@mail.gmail.com>
Subject: Re: [PING][PATCH v3] x86: Use `get_random_u8' for kernel stack offset randomization
To:     "H. Peter Anvin" <hpa@zytor.com>
Cc:     "Maciej W. Rozycki" <macro@orcam.me.uk>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Kees Cook <keescook@chromium.org>, x86@kernel.org,
        linux-kernel@vger.kernel.org
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On Tue, Feb 14, 2023 at 9:43 PM H. Peter Anvin <hpa@zytor.com> wrote:
> No, I do indeed agree. We're talking something that is a part of an opera=
tion that is already fairly expensive. Now, if RDRAND is available on the h=
ardware then that could be used if someone really wants it to go faster... =
but get_random_*() seems saner than doing ad hoc hacks.

Do you want to go ahead and apply Maciej's patch in [1] then?

[1] https://lore.kernel.org/lkml/alpine.DEB.2.21.2301302011150.55843@angie.=
orcam.me.uk/