Re: getrandom and getentropy

[Andreas Gustafsson <gson%gson.org@localhost>]

nia wrote:
> > OpenBSD guarantees that there is an entropy seed from the boot loader,
> > which is very different from NetBSD's "best effort".  Was this not
> > already the case when the getentropy API was introduced?
> 
> We do the same, on supported architectures. In addition to reading
> from CPU HWRNGs extremely early in the kernel, the bootloader
> provides a seed. Then, once userland is ready, all entropy is
> consolidated.
> 
> At the risk of recieving more angry private emails from Mr. de Raadt,
> (in the bootblocks!), if what OpenBSD does satisfies you, what
> NetBSD does should also satisfy you.

For the OpenBSD strategy to work, the system needs to actually refuse
to run if the seed can't be loaded (or full entropy achieved in some
other way).  NetBSD doesn't do that.  As long as there is any way
userland can start before full entropy has been achieved, all APIs
that provide randomness for security purposes must support blocking
(or returning errors).
-- 
Andreas Gustafsson, gson%gson.org@localhost