Messages in this thread | | | Subject | Re: [PATCH] x86/efi: pull NV+BS variables out before we exit boot services | From | James Bottomley <> | Date | Tue, 19 Mar 2013 18:40:56 +0000 |
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On Tue, 2013-03-19 at 18:28 +0000, Matthew Garrett wrote: > On Tue, Mar 19, 2013 at 06:23:31PM +0000, James Bottomley wrote: > > > The scheme we discussed, unless something radically changed, was to > > convey a temporary key pair via a mechanism to later verify the > > hybernate kernel on a resume. That only requires reboot safe knowledge > > of the public key. The private key can be conveyed in BS only (not NV), > > and should be consumed (as in deleted) by the OS when it receives it, so > > it wouldn't be exposed by this patch. > > It requires the key to survive the system being entirely powered down, > which means it needs to be BS+NV. It shouldn't be possible for userspace > to access this key.
It requires the *public* key to survive power down, certainly. The private key can be thrown away once the hibernate image is signed. I think the scheme can be constructed so the private key is never in NV storage ... that also makes it more secure against tampering.
James
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