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

Jiri Kosina
2013-02-28T23:45:27Z

On Thu, 28 Feb 2013, Matthew Garrett wrote:

> > But the real harm is being done by the i_own_your_ring0.ko module, which
> > can be modprobed on all the systems where the signed "hello world" binary
> > has been keyctl-ed before it was blacklisted.
>
> 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?

This security model seems to be quite seriously flawed to me (in a sense
that it has nothing to do with chain of trust as mandated by X509 even
though it tries to pretend the opposite)

And frankly, Linus' proposal at [1] doesn't really make it any better in
principle, it just keeps the whole thing out of kernel.

[1] https://lkml.org/lkml/2013/2/21/228

> > In other words -- you blacklist the population of the key on systems by
> > blakclisting the key-carrying binary, but the key remains trusted on
> > whatever system the binary has been processed by keyctl before. Right?
>
> You have to re-load it on every boot, it's not a permanent thing.

That unfortunately seems to be very weak security measure as well.

Thanks,

--
Jiri Kosina
SUSE Labs