[PATCH v1 1/2] random-bits: Factor out entropy generating function

[Jason A. Donenfeld]

Hi Cristian,

On Thu, Mar 31, 2022 at 5:57 PM Cristian Rodríguez
<crrodriguez@opensuse.org> wrote:
>
> On Thu, Mar 31, 2022 at 12:32 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> >
> > Just so we're on the same page here, is this a discussion about
> > optimizing https://code.woboq.org/userspace/glibc/include/random-bits.h.html
> > ?
> >
> > You just need a super fast random uint32_t for some future pthread changes?
> >
> > If so, I can send a patch to return moderately secure integers here really fast.
> >
> > Jason
>
> That would be great if is better than the current solution.

Alright, well, here's something: https://xn--4db.cc/YQOxDP6Z/c

This is somewhat "secure", and maybe overkill.

I can adjust this to have additional security properties (for example,
preventing that counter from running backwards). Or I can adjust it to
be even faster and have fewer security properties. Or maybe bench this
and you'll find that it's fine.

I suspect the only thing we really care about here is not leaking the
AT_RANDOM value somehow, and siphash usually does a good job at that.

Thoughts?

Jason