On Fri, Jul 11, 2014 at 06:56:26PM +0530, Amit Shah wrote: > On (Wed) 09 Jul 2014 [12:07:25], Jason Cooper wrote: > > Amit, Kees, > > (snip) > > > I'm cooling to the idea of the init function for virtio-rng, and it > > might be best just to admit that there's no way to seed the entropy pool > > from the virtio-rng at probe time. After all, once userspace is up, the > > system should take advantage of /dev/hwrng for the generation of > > long-term keys. Either via rngd feeding /dev/random, or directly. > > > > As for the follow-on patch you asked about, I think that's fine. More > > entropy can't hurt. > > > > The below patch might be worth considering so that the user of a system > > with only virtio-rng can kick the entropy pool as they see fit. It's > > probably not too kosher as is, but if the idea is liked, I could clean > > it up and submit. > > > > The advantage is that users don't need to have rngd installed and > > running on the system in order to jump-start the entropy pool. > > ... so a udev rule that looks for the new sysfs file, and asks the > kernel to do its thing? Or, as simple as: [ -e /sys/.../rng_seed_kernel ] && echo "0" >/sys/.../rng_seed_kernel in the initrd. It needs to run *before* any init scripts which may create keys. > And maybe even a patch to rngd that looks for this file and does a > similar thing? I'm not opposed to that, but it doesn't fit the problem I'm trying to solve. Basically, average systems, not trying to be Ft Knox-secure, but needing to generate long-term keys at first boot. These systems won't have an hwrng installed, but should use one if available. eg virtio-rng, or any of the on-die SoC hwrngs. > There's also the option to use a delayed workqueue item, that will > succeed if probe has finished. This method doesn't have userspace > dependencies. Hmm, I like that idea better. No ABI change to maintain, no userspace changes... You obviously know virtio-rng better than I do, care to take a crack at it? thx, Jason. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
