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From: "fweimer at redhat dot com" <sourceware-bugzilla@sourceware.org>
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Subject: [Bug libc/29437] arc4random is too slow
Date: Mon, 08 Aug 2022 12:37:15 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D29437

--- Comment #8 from Florian Weimer <fweimer at redhat dot com> ---
(In reply to Cristian Rodr=C3=ADguez from comment #4)
> (In reply to Miroslav Lichvar from comment #0)
>=20
> > This can be fixed easily in the chrony source code, but I thought it mi=
ght
> > be a good example of a real-world application impacted by this change a=
nd
> > there could be others.
>=20
> You need a PRNG, seeded by a single call to arc4random_buf.. (xoroshiro12=
8+?)
> People are unfortunately rejecting your usecase as invalid because this d=
oes
> not require a csprng. :-( (to me that sums up everything that is wrong, y=
ou
> known you don't need one, but notmal averege joe programmer has no idea of
> all the subtleties ans is stuck with using random() ..)

Absolutely not. The idea behind arc4random is that an entire distribution c=
an
use this function without worrying performance or properties of the generat=
ed
stream of randomness. It was designed for a search-and-replace of calls to
random, without case-by-case reviews if the change is actually required for
security reasons. If the glibc implementation does not meet that, we have
failed.

--=20
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