Re: [GIT PULL] Kernel lockdown for secure boot

From: David Howells
Date: Wed Apr 04 2018 - 09:57:25 EST

Theodore Y. Ts'o <tytso@xxxxxxx> wrote:

> > Lockdown mode restricts kexec to booting an authorised image (where the
> > authorisation may be by signature or by IMA).
> If that's true, then Matthew's assertion that lockdown w/o secure boot
> is insecure goes away, no?


Lockdown prevents the running kernel from being modified (or, at least, that's
the hope).

But it doesn't do anything to prevent the kernel being modified before
lockdown is engaged.

We are trying to use secureboot to protect the system to the point that
lockdown can take over.