[Fedora-xen] Re: more random device badness in 2.6.18 :(

Gabor Gombas gombasg at sztaki.hu
Tue Oct 10 23:32:14 UTC 2006


On Tue, Oct 10, 2006 at 11:03:58PM +0200, Paul Wouters wrote:

> Why is this happening in userland?

Because whether the provided data is "random enough" is a policy
decision, and policy does not belong in the kernel.

> Will rng-tools run on every bare Linux
> system now? Including embedded systems?

Why not? Alternatively you can always create your own version. Open
source does not mean you get everything for free; it means you _can_ do
the work if you want to.

> How about xen guests who don't have
> direct access to the host's hardware (or software) random?

If they don't have access to the host's hardware, then they do not have a
/dev/hw_random device. What's your question? And how that's different
from machines not having a hw rng at all?

> Why is this entropy management not part of the kernel? So for Openswan to
> work correctly, it would need to depend on another daemon that may or may
> not be available and/or running?

No. It only has to depend on /dev/(u)random. How the entropy is obtained
(from /dev/hw_random, from the soundcard's white noise or from
elsewhere) is none of Openswan's business.  Tha'ts up to the system
administrator or distribution maker to decide and set up.

> I still believe /dev/random should just give the best random possible for
> the machine. Wether that is software random, or a piece of hardware, should
> not matter. That's the kernel's internal state and functioning.

Gabor

-- 
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     MTA SZTAKI Computer and Automation Research Institute
                Hungarian Academy of Sciences
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