Re: [RFC] Second attempt at kernel secure boot support

From: James Bottomley
Date: Thu Nov 01 2012 - 05:59:10 EST


On Thu, 2012-11-01 at 10:45 +0100, Jiri Kosina wrote:
> On Thu, 1 Nov 2012, James Bottomley wrote:
>
> > I'm actually just struggling to understand the use case for these more
> > esoteric protections.
>
> I believe the real point is drawing a clear line between trusted and
> untrusted (with root being userspace, hence implicitly untrusted), and
> disallowing "legitimate crossing" of this line.

But that doesn't really help me: untrusted root is an oxymoron. I get
capability separated systems, where you invest trust in layers and you
make each layer small and verifiable, so you have a granular trust
policy you build up. I really don't understand the use case for trying
to remove a small portion of trust from the huge trust domain of root
and then doing a massive amount of fixup around the edges because
there's leaks all over the place from the trust that root still has. It
all seems to be a bit backwards. If you just begin with the capability
separated granular system, I don't see why it doesn't all just work with
what we have today.

James


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