From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [kernel-hardening] Re: [PATCH] x86: make IDT read-only
Date: Tue, 09 Apr 2013 11:59:15 -0700
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To: Eric Northup <digitaleric@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>, Alex Shi <alex.shi@intel.com>, Jeremy Fitzhardinge <jeremy@goop.org>, Will Drewry <wad@chromium.org>, Kees Cook <keescook@chromium.org>, Julien Tinnes <jln@google.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Frederic Weisbecker <fweisbec@gmail.com>, Dan Rosenberg <drosenberg@vsecurity.com>, "x86@kernel.org" <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>, Steven Rostedt <rostedt@goodmis.org>, Borislav Petkov <borislav.petkov@amd.com>, Ingo Molnar <mingo@redhat.com>, "kernel-hardening@lists.openwall.com" <kernel-hardening@lists.openwall.com>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
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On 04/09/2013 11:54 AM, Eric Northup wrote:
> 
> The GDT is a problem if the address returned by 'sgdt' is
> kernel-writable - it doesn't necessarily reveal the random offset, but
> I'm pretty sure that writing to the GDT could cause privilege
> escalation.
> 

That is a pretty safe assumption...

	-hpa