From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Matt Fleming <matt@console-pimps.org>,
linux-efi@vger.kernel.org, lkml <linux-kernel@vger.kernel.org>
Subject: Re: Corrupted EFI region
Date: Wed, 31 Jul 2013 22:54:23 +0100 [thread overview]
Message-ID: <20130731215423.GA2628@srcf.ucam.org> (raw)
In-Reply-To: <20130731215130.GA6087@pd.tnic>
On Wed, Jul 31, 2013 at 11:51:30PM +0200, Borislav Petkov wrote:
> But the problem is, something messes up the upper boundary of the region
> and it is an EFI_BOOT_SERVICES_DATA region which we need for the runtime
> services mapping and if we can't map it properly, we're probably going
> to miss functionality or not have runtime at all.
"Easiest" way around this would probably be to stash the address map
after ExitBootServices() and compare it at SetVirtualAddressMap() time,
then take the widest boundaries and trim the e820 map to match. This is
obviously dependent upon the system not allocating anything further
after that, but it seems safest. The worst case is finding the firmware
writing over bits of the kernel.
--
Matthew Garrett | mjg59@srcf.ucam.org
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Garrett <mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org>
To: Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>
Cc: Matt Fleming
<matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>,
linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
lkml <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: Corrupted EFI region
Date: Wed, 31 Jul 2013 22:54:23 +0100 [thread overview]
Message-ID: <20130731215423.GA2628@srcf.ucam.org> (raw)
In-Reply-To: <20130731215130.GA6087-fF5Pk5pvG8Y@public.gmane.org>
On Wed, Jul 31, 2013 at 11:51:30PM +0200, Borislav Petkov wrote:
> But the problem is, something messes up the upper boundary of the region
> and it is an EFI_BOOT_SERVICES_DATA region which we need for the runtime
> services mapping and if we can't map it properly, we're probably going
> to miss functionality or not have runtime at all.
"Easiest" way around this would probably be to stash the address map
after ExitBootServices() and compare it at SetVirtualAddressMap() time,
then take the widest boundaries and trim the e820 map to match. This is
obviously dependent upon the system not allocating anything further
after that, but it seems safest. The worst case is finding the firmware
writing over bits of the kernel.
--
Matthew Garrett | mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org
next prev parent reply other threads:[~2013-07-31 21:54 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-31 20:54 Corrupted EFI region Borislav Petkov
2013-07-31 20:54 ` Borislav Petkov
2013-07-31 20:58 ` Matthew Garrett
2013-07-31 20:58 ` Matthew Garrett
2013-07-31 21:51 ` Borislav Petkov
2013-07-31 21:51 ` Borislav Petkov
2013-07-31 21:54 ` Matthew Garrett [this message]
2013-07-31 21:54 ` Matthew Garrett
2013-08-01 16:51 ` Borislav Petkov
2013-08-01 16:51 ` Borislav Petkov
2013-07-31 21:55 ` David Woodhouse
2013-07-31 21:55 ` David Woodhouse
2013-08-01 16:49 ` Borislav Petkov
2013-08-01 16:49 ` Borislav Petkov
2013-08-05 11:27 ` [edk2] " Laszlo Ersek
2013-08-05 11:27 ` Laszlo Ersek
2013-08-05 13:02 ` Borislav Petkov
2013-08-05 13:02 ` Borislav Petkov
2013-08-05 13:39 ` Laszlo Ersek
2013-08-05 13:39 ` Laszlo Ersek
2013-08-05 14:03 ` Borislav Petkov
2013-08-05 14:03 ` Borislav Petkov
2013-08-05 14:27 ` Laszlo Ersek
2013-08-05 14:27 ` Laszlo Ersek
2013-08-05 14:40 ` Borislav Petkov
2013-08-05 14:40 ` Borislav Petkov
2013-08-05 15:15 ` Laszlo Ersek
2013-08-05 15:15 ` Laszlo Ersek
2013-08-05 15:34 ` James Bottomley
2013-08-05 15:34 ` James Bottomley
2013-08-05 16:27 ` Laszlo Ersek
2013-08-05 16:27 ` Laszlo Ersek
2013-08-05 16:12 ` Borislav Petkov
2013-08-05 16:12 ` Borislav Petkov
2013-08-05 16:41 ` Laszlo Ersek
2013-08-05 16:41 ` Laszlo Ersek
2013-08-05 16:47 ` Borislav Petkov
2013-08-05 16:47 ` Borislav Petkov
2013-08-05 17:00 ` Kinney, Michael D
2013-08-05 17:00 ` Kinney, Michael D
2013-08-05 17:09 ` Laszlo Ersek
2013-08-05 17:09 ` Laszlo Ersek
2013-08-05 21:26 ` Laszlo Ersek
2013-08-05 21:26 ` Laszlo Ersek
2013-08-05 22:08 ` Borislav Petkov
2013-08-05 22:08 ` Borislav Petkov
2013-08-06 14:10 ` Borislav Petkov
2013-08-06 14:10 ` Borislav Petkov
2013-08-06 15:31 ` Laszlo Ersek
2013-08-06 15:31 ` Laszlo Ersek
2013-08-07 15:19 ` Borislav Petkov
2013-08-07 17:23 ` Andrew Fish
2013-08-07 17:23 ` Andrew Fish
2013-08-07 20:19 ` Matt Fleming
2013-08-07 20:19 ` Matt Fleming
2013-08-07 20:24 ` Matt Fleming
2013-08-07 20:24 ` Matt Fleming
2013-08-07 21:10 ` Andrew Fish
2013-08-07 21:10 ` Andrew Fish
2013-08-07 21:23 ` Matthew Garrett
2013-08-08 10:17 ` Matt Fleming
2013-08-08 10:17 ` Matt Fleming
2013-08-08 13:46 ` Andrew Fish
2013-08-08 13:46 ` Andrew Fish
2013-09-02 8:19 ` Matt Fleming
2013-09-02 8:19 ` Matt Fleming
2013-09-13 20:38 ` jerry.hoemann
2013-09-13 20:38 ` jerry.hoemann-VXdhtT5mjnY
2013-09-16 10:59 ` Matt Fleming
2013-09-16 10:59 ` Matt Fleming
2013-09-16 11:50 ` Laszlo Ersek
2013-09-16 11:50 ` Laszlo Ersek
2013-09-16 15:57 ` Josh Triplett
2013-09-16 15:57 ` Josh Triplett
2013-09-16 16:25 ` Laszlo Ersek
2013-09-16 16:25 ` Laszlo Ersek
2013-09-16 16:27 ` Matthew Garrett
2013-09-16 16:27 ` Matthew Garrett
2013-09-16 16:29 ` Josh Triplett
2013-09-16 16:29 ` Josh Triplett
2013-09-18 19:24 ` jerry.hoemann
2013-09-18 19:24 ` jerry.hoemann-VXdhtT5mjnY
2013-09-20 9:06 ` Matt Fleming
2013-09-20 9:06 ` Matt Fleming
2013-08-07 17:49 ` Laszlo Ersek
2013-08-07 17:49 ` Laszlo Ersek
2013-08-08 15:02 ` Borislav Petkov
2013-08-08 15:02 ` Borislav Petkov
2013-08-08 21:45 ` Brian J. Johnson
2013-08-08 21:45 ` Brian J. Johnson
2013-08-18 7:33 ` Jordan Justen
2013-08-18 7:33 ` Jordan Justen
2013-08-05 15:50 ` Andrew Fish
2013-08-05 15:50 ` Andrew Fish
2013-08-05 18:12 ` Borislav Petkov
2013-08-05 18:12 ` Borislav Petkov
2013-08-05 21:37 ` H. Peter Anvin
2013-08-05 21:37 ` H. Peter Anvin
2013-08-05 21:41 ` Borislav Petkov
2013-08-05 21:41 ` Borislav Petkov
2013-08-05 21:49 ` H. Peter Anvin
2013-08-05 21:49 ` H. Peter Anvin
2013-08-05 21:55 ` Laszlo Ersek
2013-08-05 21:55 ` Laszlo Ersek
2013-08-05 22:52 ` James Bottomley
2013-08-05 22:52 ` James Bottomley
2013-08-06 7:26 ` Laszlo Ersek
2013-08-06 7:26 ` Laszlo Ersek
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