Messages in this thread | | | From | Ard Biesheuvel <> | Date | Tue, 7 Jun 2022 16:51:43 +0200 | Subject | Re: [PATCH] random: defer use of bootloader randomness to random_init() |
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On Tue, 7 Jun 2022 at 16:48, Jason A. Donenfeld <Jason@zx2c4.com> wrote: > > Hi Ard, > > On Tue, Jun 07, 2022 at 04:19:26PM +0200, Ard Biesheuvel wrote: > > #include <stdio.h> > > #include <stdlib.h> > > #include <sys/random.h> > > > > static unsigned char buf[16]; > > > > int main(void) > > { > > for (int i = 0; i < 1000000; i++) { > > if (getrandom(buf, sizeof(buf), > > GRND_RANDOM | GRND_NONBLOCK) < sizeof(buf)) { > > fprintf(stderr, "getrandom() error!\n"); > > exit(-1); > > } > > } > > return 0; > > } > > I'm actually more worried about the random input flow than the random > output flow and branch misprediction. But more generally, I'd just like > to keep that code as cold as possible after crng init. It's code that's > only used in that one phase and then never again. It can be entirely > disabled. > > Anyway, we've got a few solutions now to pick from on the random.c side > of things. I'm going to investigate the arm32 situation next. And then > we'll see what it all looks like. >
Sure.
It would be helpful if some other folks could chime in as well?
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