Re: [PATCH 5/7] efi: Get the secure boot status [ver #3]

From: David Howells
Date: Fri Nov 25 2016 - 07:45:24 EST

Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:

> Yes. In pre-2.6, DeployedMode is not a reserved name, and so it may be
> possible for someone to slip in a DeployedMode=0 on a secure boot
> enabled system to trick the kernel into thinking lockdown should be
> disabled.

How does one get the version number? Unfortunately, searching the document
for 'version' doesn't help as every page has that in the footer:-/

> > + if (val == 1)
> > + return 0;
> I think the logic is the wrong way around here. Secure Boot is enabled
> if SecureBoot=1 and SetupMode=0, unless DeployedMode=0. So you should
> return 0 here if val == 0, but only when running on 2.6 or later.

Good point.