Re: Trusted kernel patchset for Secure Boot lockdown

From: Kees Cook
Date: Wed Feb 26 2014 - 16:11:37 EST


On Wed, Feb 26, 2014 at 12:11 PM, Matthew Garrett
<matthew.garrett@xxxxxxxxxx> wrote:
> The conclusion we came to at Plumbers was that this patchset was basically
> fine but that Linus hated the name "securelevel" more than I hate pickled
> herring, so after thinking about this for a few months I've come up with
> "Trusted Kernel". This flag indicates that the kernel is, via some
> external mechanism, trusted and should behave that way. If firmware has
> some way to verify the kernel, it can pass that information on. If userspace
> has some way to verify the kernel, it can set the flag itself. However,
> userspace should not attempt to use the flag as a means to verify that the
> kernel was trusted - untrusted userspace could have set it on an untrusted
> kernel, but by the same metric an untrusted kernel could just set it itself.
>
> If people object to this name then I swear to god that I will open a poll
> on Phoronix to decide the next attempt and you will like that even less.

For the Chrome OS use-case, it might be better described as "untrusted
userspace", but that seems unfriendly. :) The "trusted kernel" name
seems fine to me.

-Kees

--
Kees Cook
Chrome OS Security
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