Seth Forshee <seth.forshee@xxxxxxxxxxxxx> wrote: > > This begs the question on how we'd manage keys for firmware signing on > > linux-firmare. Since the keys are x509 keys we need a CA. Based on some > > initial discussions it would seem we'd need the Linux Foundation to create > > a key, this would be embedded in the kernel and that key would be used to > > sign Kyle's key. Kyle would in turn use his key for signing > > linux-firmware files. David, Kyle, did I summarize this correctly ? > > I raised the question of key revocation when we discussed this on irc, > but it wasn't answered to my satisfaction. If a key signed by the > kernel-embedded key is compromised, how can that key be revoked so that > it is no longer trusted? > > Someone mentioned UEFI blacklists, which I don't know much about, but > not all systems have UEFI. The only reliable option that comes to mind > for me is an in-kernel blacklist of keys which should no longer be > trusted. Key revocation is generally an unpleasant problem. How do you inform a system that a key of any sort is revoked? With PGP, for instance, you might be able to connect to the net and consult a server. UEFI has a blacklist that can theoretically be used to prevent both usage of a key and usage of a particular object. As I understand it, the blacklist in UEFI is just a table of SHA256 hashes. Relying on UEFI presents three problems, though: (1) the system admin has to manually, as far as I'm aware, inform the BIOS; (2) the UEFI storage is limited; and (3) not all systems have UEFI. What you do on a non-UEFI system, I'm not sure. If the kernel isn't verified by the loader or the system firmware then you don't have a 'fully' secure system anyway and the blacklist may be of questionable value. David -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
