[PATCH ustream-ssl] ustream-mbedtls: Use getrandom() instead of /dev/urandom

[Torsten Duwe]

Hi Hauke!

On Sun, 19 Feb 2023 21:06:15 +0100
Hauke Mehrtens <hauke at hauke-m.de> wrote:

> Hi Torsten,
> 
> Sorry for the late answer, I forgot about this mail thread.

No problem.

> > On Sun, 29 Jan 2023 17:08:38 +0100
> > Hauke Mehrtens <hauke at hauke-m.de> wrote:

[...]

> ustreamss uses the randomness to generate session keys (including 
> ephemeral keys), IVs and padding. The long term keys are generated in a 
> different application.

[...]

> 
> I think we should wait with creating TLS sessions till we have enough 
> random data to do it securely. I tested this on a lantiq xrx200 (MIPS) 
> device and it was initialized much before the LAN interface was up.
                                ^^^^^^^^^^^
Yes. Good that it works out this way. Otherwise you'd have had a tough
decision to make.

> The code in ustream-mbedtls.c was probably initially written when 
> /dev/random was still blocking when too much entropy was read out of the 
> pool.

I guess so, too.

> I will rename the function.

Cool. You can add my review tag if you want...

	Torsten