Re: [PATCH] random: add a config option to trust the CPU's hwrng

From: Theodore Y. Ts'o
Date: Wed Jul 18 2018 - 10:26:36 EST


On Wed, Jul 18, 2018 at 09:22:13AM +0200, Yann Droneaud wrote:
>
> The text message should explain this is only relevant during
> initialization / early boot.
>
> The config option name should state this.

There are other workarounds for hangs that happen after initialization
/ early boot, yes. They are of varying levels of quality / safely,
but that's neither here nor there.

However, enabling config option means that the CRNG will be
initialized with potentially information available to the CPU
manufacturer and/or Nation States, and this persists *after*
initialization / early boot. So to say, "we're perfectly safe after
we leave initialization / early boot" is not true.

So I'd much rather make it clear that we are trusting the CPU
manufacturer far more than just during early boot.

Cheers,

- Ted