On Wed 2013-09-25 15:16:54, James Bottomley wrote: > On Wed, 2013-09-25 at 17:25 -0400, Alan Stern wrote: > > On Wed, 25 Sep 2013, David Howells wrote: > > > > > I have pushed some keyrings patches that will likely affect this to: > > > > > > http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=keys-devel > > > > > > I intend to ask James to pull these into his next branch. If he's happy to do > > > so, I can look at pulling at least your asymmetric keys patch on top of them. > > > > This suggests a point that I raised at the Linux Plumbers conference: > > > > Why are asymmetric keys used for verifying the hibernation image? It > > seems that a symmetric key would work just as well. And it would be a > > lot quicker to generate, because it wouldn't need any high-precision > > integer computations. > > The reason is the desire to validate that the previous kernel created > something which it passed on to the current kernel (in this case, the > hibernation image) untampered with. To do that, something must be > passed to the prior kernel that can be validated but *not* recreated by > the current kernel. I don't get this. Why is it important that current kernel can't recreate the signature? Current kernel is not considered malicious (if it were, you have worse problems). Pavel PS: And yes, it would be nice to have Documentation/power/swsusp-uefi.txt (or something) explaining the design. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
