Messages in this thread | | | Date | Wed, 16 Jul 2014 10:23:16 +0300 | From | Gleb Natapov <> | Subject | Re: [PATCH 0/4] random,x86,kvm: Add and use MSR_KVM_GET_RNG_SEED |
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On Wed, Jul 16, 2014 at 09:10:27AM +0200, Daniel Borkmann wrote: > On 07/16/2014 08:41 AM, Gleb Natapov wrote: > >On Tue, Jul 15, 2014 at 07:48:06PM -0700, Andy Lutomirski wrote: > >>virtio-rng is both too complicated and insufficient for initial rng > >>seeding. It's far too complicated to use for KASLR or any other > >>early boot random number needs. It also provides /dev/random-style > >>bits, which means that making guest boot wait for virtio-rng is > >>unacceptably slow, and doing it asynchronously means that > >>/dev/urandom might be predictable when userspace starts. > >> > >>This introduces a very simple synchronous mechanism to get > >>/dev/urandom-style bits. > > > >Why can't you use RDRAND instruction for that? > > You mean using it directly? I think simply for the very same reasons > as in c2557a303a ... So you trust your hypervisor vendor more than you trust your CPU vendor? :)
-- Gleb.
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