Re: [PATCH 2/2] efi: Validate UEFI boot variables

On Mon, Apr 30, 2012 at 08:00:30PM -0400, Shea Levy wrote:

On 04/30/2012 04:11 PM, Matthew Garrett wrote:

quoted

A common flaw in UEFI systems is a refusal to POST triggered by a malformed
boot variable. Once in this state, machines may only be restored by
reflashing their firmware with an external hardware device. While this is
obviously a firmware bug, the serious nature of the outcome suggests that
operating systems should filter their variable writes in order to prevent
a malicious user from rendering the machine unusable.

Any chance this will make it safe to use efibootmgr on Apple EFI
firmware? I've been afraid to use it because I've read it can
silently brick the device due to a mistake in efibootmgr. Obviously
this won't correct that mistake, but with this applied should a
successful variable set imply that the firmware wasn't bricked?

As far as I know that's been fixed since 
202f9d0a41809e3424af5f61489b48b622824aed - the problem wasn't 
efibootmgr, the problem was Apple's firmware overwriting itself.

-- 
Matthew Garrett | mjg59@srcf.ucam.org