|| ||Jiri Kosina <jkosina-AT-suse.cz> |
|| ||Matthew Garrett <mjg-AT-redhat.com> |
|| ||Re: [RFC] Second attempt at kernel secure boot support |
|| ||Wed, 31 Oct 2012 15:50:00 +0100 (CET)|
|| ||Article, Thread
On Mon, 29 Oct 2012, Matthew Garrett wrote:
> > > This is pretty much identical to the first patchset, but with the capability
> > > renamed (CAP_COMPROMISE_KERNEL) and the kexec patch dropped. If anyone wants
> > > to deploy these then they should disable kexec until support for signed
> > > kexec payloads has been merged.
> > Apparently your patchset currently doesn't handle device firmware loading,
> > nor do you seem to mention in in the comments.
> > I believe signed firmware loading should be put on plate as well, right?
> I think that's definitely something that should be covered. I hadn't
> worried about it immediately as any attack would be limited to machines
> with a specific piece of hardware, and the attacker would need to expend
> a significant amount of reverse engineering work on the firmware - and
> we'd probably benefit from them doing that in the long run...
Now -- how about resuming from S4?
Reading stored memory image (potentially tampered before reboot) from disk
is basically DMA-ing arbitrary data over the whole RAM. I am currently not
able to imagine a scenario how this could be made "secure" (without
storing private keys to sign the hibernation image on the machine itself
which, well, doesn't sound secure either).
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