linux-kernel - Re: [PATCH 0/4] EFI 1:1 mapping

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 03 Jun 2013 07:27:22 -0700
From:	James Bottomley <James.Bottomley@...senPartnership.com>
To:	Borislav Petkov <bp@...en8.de>
Cc:	Matthew Garrett <mjg59@...f.ucam.org>,
	Linux EFI <linux-efi@...r.kernel.org>,
	Matt Fleming <matt@...sole-pimps.org>,
	Jiri Kosina <jkosina@...e.cz>, X86-ML <x86@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>, Borislav Petkov <bp@...e.de>
Subject: Re: [PATCH 0/4] EFI 1:1 mapping

On Mon, 2013-06-03 at 10:11 +0200, Borislav Petkov wrote:
> On Sun, Jun 02, 2013 at 11:56:20PM +0100, Matthew Garrett wrote:
> > I've just run Windows 8 under a hacked up copy of OVMF that dumps
> > the data passed to SetVirtualAddressMap. It seems that Windows *is*
> > mapping the runtime services to higher addresses - so presumably the
> > 1:1 mapping is in addition to the virtual mapping.
> 
> But but, once we call SetVirtualAddressMap with the set of addresses of
> the runtime services, only those can be used after, right? If so, we
> can't have both (this is at least my understanding)...

That's correct.  I think not calling SetVirtualAddressMap() and just
using a 1:1 mapping is far safer (having looked at what tianocore does
for SetVirtualAddressMap()).  The chances are that all the UEFI bioses
are only tested with windows, so the pointer chases it has to do to
switch address maps only work with the operations windows does.

James


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/