Re: getrandom and getentropy

[maya%NetBSD.org@localhost]

On Tue, May 12, 2020 at 12:37:57PM +0000, nia wrote:
> These use arandom exclusively on NetBSD:
> - gnutls (via nettle _rnd_get_system_entropy)
>   Prefers getentropy and only uses getrandom if there's no getentropy.
> - openssl (syscall_random)
>   Prefers getentropy and only uses getrandom if there's no getentropy.
> - libuv (uv__random)
>   Prefers getentropy on macOS and Android.
> - rust (getrandom crate, standard library and compiler)
> - FreeBSD libc (to implement getentropy)

This is missing the "full disclosure: I added all but one of those
myself".

Rust used to read a byte from /dev/random, then use /dev/urandom. This
was bad in "entropy depletion" NetBSD<=9, it no longer is.

I don't understand this entire argument, we are arguing that
getrandom(0) is very important to provide since we want to offer a
no-file version of "read byte from /dev/random then read from
/dev/urandom".

Then we go against this idea and add getentropy as /dev/urandom.
linux implements getentropy as getrandom(0), so it's a valid
implementation that people acknowledge.