On Tue, Aug 09, 2016 at 02:04:44PM +0000, Jason Cooper wrote: > > iiuc, Ted, you're saying using the hw_random framework would be > disasterous because despite most drivers having a default quality of 0, > rngd assumes 1 bit of entropy for every bit read? Sorry, what I was trying to say (but failed) was that bypassing the hwrng framework and injecting entropy directly the entropy pool was disatrous. > Thankfully, most hw_random drivers don't set the quality. So unless the > user sets the default_quality param, it's zero. The fact that this is "most" and not "all" does scare me a little. As far as I'm concerned *all* hw_random drivers should set quality to zero, since it should be up to the system administrator. Perhaps the one exception is virtio_rng, since if you don't trust the hypvervisor, the security of the VM is hopeless. That being said, I have seen configurations of KVM which use: -object rng-random,filename=/dev/urandom,id=rng0 \ -device virtio-rng-pci,rng=rng0 Which is somewhat non-ideal. (Try running od -x /dev/random on such a guest system....) - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
