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

From: Matthew Garrett
Date: Mon Feb 25 2013 - 10:45:57 EST

On Mon, Feb 25, 2013 at 03:28:32PM +0100, Florian Weimer wrote:

> But what puzzles me most is why anyone would assume that the UEFI
> application signing process somehow ensures that the embedded
> certificate is non-malicious. We cannot even track it back to the
> submitter because the third-pary market place UEFI authority only
> issues pseudonymous proxy certificates. This utterly useless for any
> purpose whatsoever, with the notable exception of avoding one
> additional step when setting up a dual-boot machine (which will not
> even work reliably until we switch to overwriting the Windows boot
> loader, like in the pre-UEFI days).

If your firmware trusts objects signed by Microsoft, you have to assume
that objects signed by Microsoft are trustworthy. There's no way to
build a security model otherwise. Are Microsoft trustworthy? We don't
know. If you don't trust Microsoft, remove their key from db.

> Seriously, folks, can we go back one step and discuss what problem you
> are trying to solve? Is it about allowing third-party kernel modules
> in an environment which does not allow unsigned ring 0 code execution?

The problem I'm trying to solve is "Don't permit Linux to be used as a
bootloader for backdoored versions of other operating systems". Any
other security benefit is a happy side effect.

Matthew Garrett | mjg59@xxxxxxxxxxxxx
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at