Re: [PATCH v10 2/7] KEYS: trusted: allow use of kernel RNG for key material

[Jason A. Donenfeld]

On Fri, May 13, 2022 at 04:57:00PM +0200, Ahmad Fatoum wrote:
> +	trusted.rng=	[KEYS]
> +			Format: <string>
> +			The RNG used to generate key material for trusted keys.
> +			Can be one of:
> +			- "kernel"
> +			- the same value as trusted.source: "tpm" or "tee"
> +			- "default"
> +			If not specified, "default" is used. In this case,
> +			the RNG's choice is left to each individual trust source.
> +

As a general mechanism, I object to this. The kernel's RNG must be
trusted in the first place for key material. That's the whole point of
it.

However, it sounds like you're not proposing a general mechanism, but
just something particular to this "trusted keys" business. In that case,
this should be a module flag, and thus not documented here, but rather
some place namespaced to your trusted keys stuff. "trusted_keys.preferred_rng={whatever}"

Jason