Re: [PATCH 2/2] lguest: virtio-rng support

From: Rusty Russell
Date: Sat May 17 2008 - 00:47:36 EST


On Friday 16 May 2008 20:49:41 Johannes Berg wrote:
> > +
> > +/* Our random number generator device reads from /dev/urandom into the Guest's
> > + * input buffers. The usual case is that the Guest doesn't want random numbers
> > + * and so has no buffers although /dev/urandom is still readable, whereas
> > + * console is the reverse.
>
> Is it really a good idea to use the hosts /dev/urandom to fill the
> guests /dev/random?

Technically it's up to rngd in the guest to decide whether to feed entropy
or not (ie. /dev/urandom or /dev/random).

If we use /dev/random in the host, we risk a DoS. But since /dev/random
is 0666 on my system, perhaps noone actually cares?

Cheers,
Rusty.
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