Re: [PATCH 00/12] One more attempt at useful kernel lockdown

From: David Lang
Date: Mon Sep 09 2013 - 14:27:18 EST


On Mon, 9 Sep 2013, Valdis.Kletnieks@xxxxxx wrote:

On Mon, 09 Sep 2013 11:49:34 -0400, Matthew Garrett said:

So, this is my final attempt at providing the functionality I'm interested
in without inherently tying it to Secure Boot. There's strong parallels
between the functionality that I'm interested in and the BSD securelevel
interface, so here's a trivial implementation.

Although all the individual patches look like sane and reasonable things
to do, I'm not at all convinced that sticking them all under control of one
flag is really the right way to do it. In particular, there probably needs
to be some re-thinking of the kexec, signed-module, and secure-boot stuff,
as it's still a moving target.

Given that we know that people want signed binaries without blocking kexec, you should have '1' just enforce module signing and '2' (or higher) implement a full lockdown including kexec.

Or, eliminate the -1 permanently insecure option and make this a bitmask, if someone wants to enable every possible lockdown, have them set it to "all 1's", define the bits only as you need them.

right now
1 lock down modules
2 lock down kexec

etc

you may also want to have a 'disable module loading after this point' in the future.

David Lang
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