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From:   Sandy Harris <sandyinchina@gmail.com>
Date:   Sat, 4 Dec 2021 17:53:41 +0800
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Subject: Re: [PATCH v43 01/15] Linux Random Number Generator
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Simo Sorce <simo@redhat.com>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>,
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Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:

> Also, why does any of this have to be in the kernel at all?

The kernel has had random(4) since Ted invented it sometime in
the 90s. There's no question it's a good idea; that's why all the BSDs
& some others have copied it. The only questions here are whether
it could be made FIPS compliant & whether it should be.

> If FIPS requires a deterministic random number generator
> that will not allow entropy to be acquired from hardware
> or external inputs,

It doesn't require that at all; in fact their DRNG design
requires an external source of random bits. However, it
requires that the source be certified & that would be a
problem for us. Intel & others might be able to get their
random number instructions certified and vendors of
crypto or SOC chips might get theirs certified, but the
kernel community could not do that.

I think the kernel's entropy collection routines are good
enough that they could, in principle, be certified, but
that would involve some work & considerable money.

> why does the
> kernel care at all?  Just write a fips_random.so library and get it
> certified and have any userspace code that cares about such a crazy
> thing to use that instead.

That does not solve the problem. The library would
also need a certified source of random inputs, so
to get it certified you'd have to get something else
certified first -- random(4), an instruction or a hardware
rng.