Messages in this thread | | | From | "Jason A. Donenfeld" <> | Date | Thu, 22 Feb 2024 00:09:32 +0100 | Subject | Re: [PATCH v3] x86/coco: Require seeding RNG with RDRAND on CoCo systems |
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On Wed, Feb 21, 2024 at 11:47 PM Dave Hansen <dave.hansen@intel.com> wrote: > OK, so we're trying to get 256 bits of seed data from RDRAND?
Yes. This fills a 32-byte buffer of longs up with output from arch_get_random_longs().
> But no pattern I could discern. Did you mean something different by > "platform drivers"?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/um/kernel/um_arch.c#n413 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/char/random.c#n655 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/gcc-plugins/latent_entropy_plugin.c#n90
> If we're going to have arch/x86-specific crud, it would be great to make > it obvious and straightforward to those of us simple folk that are > familiar with arch/x86 code.
If you insist, I'll stick a local `enum { RANDOM_BYTES_COUNT = 32 }` in that function or something. Seems unnecessary to me but if that's what you need no problem. Would that suffice? Or a different variable name? Or a comment on "what is 32 about?"
Jason
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