[PATCH] rockchip: board: Increase rng-seed size to make it sufficient for modern Linux

[Dragan Simic]

Hello,

On 2024-10-14 12:26, Alex ThreeD wrote:
> On Mon, Oct 14, 2024 at 12:10 AM Marek Vasut <marex at denx.de> wrote:
>> Let's make this override-able via environment variable, because this
>> might be growing in the future again. Does this work ?
>> 
>> size_t len = env_get_ulong("kaslrseed_size", 10, 32);
> 
> Maybe `env_get_hex("rng_seed_size", 32)` would be better? As most other 
> env are
> hexadecimal.
> 
> Actually it seems that entropy required to init pool early has 
> decreased in
> Linux 5.19 from 64 bytes (2 * CHACHA_KEY_SIZE) to 32 bytes
> (BLAKE2S_HASH_SIZE)
> https://elixir.bootlin.com/linux/v5.18/source/drivers/char/random.c#L236
> https://elixir.bootlin.com/linux/v5.19/source/drivers/char/random.c#L551
> Anyway config knob should not harm.

I think that the value received from the new environment variable
should be accepted only if it's greater than some hardcoded value,
in this case 32.  That way, someone won't be able to misconfigure
their board environment and cause the early random pool initialization
to be postponed.