[OpenWrt-Devel] [PATCH] openssl: Fix longer booting times by unblocking getrandom

Petr Štetiar ynezz at true.cz
Fri Mar 15 12:01:35 EDT 2019

Etienne Champetier <champetier.etienne at gmail.com> [2019-03-15 10:46:09]:


> Just a side note, on first boot we save a random seed using getrandom()
> https://github.com/openwrt/openwrt/blob/master/package/base-files/files/etc/init.d/urandom_seed
> https://github.com/openwrt/openwrt/blob/master/package/base-files/files/sbin/urandom_seed
> And we restore it in preinit
> https://github.com/openwrt/openwrt/blob/master/package/base-files/files/lib/preinit/81_urandom_seed

Well, it seems like we're writing the /etc/urandom.seed to the /dev/urandom
which doesn't help with initialization of CRNG, just seeding the /dev/urandom.

> So even if kernel PRNG is considered not initialized, in reality it
> is, so starting from second boot we are ~ok

Nope, see bellow.

1st boot:

 [    3.944674] urandom-seed: Seed file not found (/etc/urandom.seed)
 [   75.120166] random: fast init done
 [  140.917418] random: crng init done

2nd boot:

 [    3.938414] urandom-seed: Seeding with /etc/urandom.seed
 [   22.440981] random: fast init done
 [  135.737309] random: crng init done

-- ynezz

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