Re: [RFD] linux-firmware key arrangement for firmware signing

Kyle McMartin
2015-05-20T20:36:03Z

On Wed, May 20, 2015 at 09:04:26AM -0500, Seth Forshee wrote:
> 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.
>

I think the solution here is two-fold... first, we'll probably try some
to use a HSM for signing, so there's extremely low risk of compromise.
Secondly, if we annotate the key such that it can only be used for
firmware, a compromise of my key won't allow you to kexec or load kernel
modules.

regards, --Kyle