[PATCH v2] seedrng: limit poolsize to 256 bytes and document flock() and fsync() usage

[Bernhard Reutner-Fischer]

On Sun, 1 May 2022 18:35:00 +0200
Emmanuel Deloget <logout at free.fr> wrote:

> > There is also the case (that on my systems at least) udev
> > initialisation reads from /dev/[u]random well before the S20
> > script loads any saved entropy.
> > I've not tried to find out what the value is used for.  
> 
> I find at least one occurrence where the goal is to create a
> random delay in udev-watch.c [1].

Yes, but that spot does seem to have a fallback.

But why is the seeding being run only at S20, way after udev?
seedrng would not _have_ to rely on /dev/{,u}random being there, we
could as well mknod our own node(s) and could hence run way earlier, i
assume. Would that help? We'd probably have less jitter accumulated if
fewer other stuff did run before us, but still.

thanks,