linux-kernel - Re: Trusted kernel patchset for Secure Boot lockdown

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Message-ID: <1394746362.27846.5.camel@x230>
Date:	Thu, 13 Mar 2014 21:32:42 +0000
From:	Matthew Garrett <matthew.garrett@...ula.com>
To:	"hpa@...or.com" <hpa@...or.com>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"jmorris@...ei.org" <jmorris@...ei.org>,
	"keescook@...omium.org" <keescook@...omium.org>,
	"linux-security-module@...r.kernel.org" 
	<linux-security-module@...r.kernel.org>,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"jwboyer@...oraproject.org" <jwboyer@...oraproject.org>,
	"gnomes@...rguk.ukuu.org.uk" <gnomes@...rguk.ukuu.org.uk>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
Subject: Re: Trusted kernel patchset for Secure Boot lockdown

On Thu, 2014-03-13 at 14:28 -0700, H. Peter Anvin wrote:
> On 03/13/2014 02:24 PM, One Thousand Gnomes wrote:
> > 
> > If I have CAP_SYS_RAWIO I can make arbitary ring 0 calls from userspace,
> > trivially and in a fashion well known and documented.
> > 
> 
> ... and once we eliminate CAP_SYS_RAWIO a bunch of the patches become
> redundant.

We can only drop CAP_SYS_RAWIO if we change a bunch of the existing
CAP_SYS_RAWIO checks to something else. How do we do that without
breaking existing userspace?

-- 
Matthew Garrett <matthew.garrett@...ula.com>