Re: [GIT PULL] Load keys from signed PE binaries

Jiri Kosina
2013-02-28T23:52:55Z

On Thu, 28 Feb 2013, Matthew Garrett wrote:

> > > Sure, if you've been infected before the revocation, you'll still be
> > > infected. There's not really any good way around that.
> >
> > Which is a very substantial difference to normal X509 chain of trust,
> > isn't it?
>
> If you've loaded an x.509 certificate into the kernel and it's later
> revoked, any module signed with the key is going to be loadable until
> it's revoked. I don't see an especially large difference here?

i_own_your_ring0.ko can be modprobed long after blacklisting of "hello
world" binary hash has happened on the very particular machine in its dbx
(as there is no link, in a x509-chain-of-trust-sense, between the hash of
the PE binary and the i_own_your_ring0.ko signature key).

modprobe of a module signed by a key that has been blacklisted on the very
particular machine in its dbx is not going to work (as there is a very
direct x509 chain of trust link).

No?

Thanks,

--
Jiri Kosina
SUSE Labs