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From: "H. Peter Anvin" <hpa@zytor.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Kees Cook <keescook@chromium.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Rik van Riel <riel@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Matthew Garrett <matthew.garrett@nebula.com>,
	Rob Landley <rob@landley.net>,
	Eric Biederman <ebiederm@xmission.com>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Mel Gorman <mgorman@suse.de>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	kexec@lists.infradead.org
Subject: Re: [PATCH v2] kexec: add sysctl to disable kexec
Date: Tue, 10 Dec 2013 10:54:00 -0800	[thread overview]
Message-ID: <52A76348.5080803@zytor.com> (raw)
In-Reply-To: <20131210183352.GD13909@redhat.com>

On 12/10/2013 10:33 AM, Vivek Goyal wrote:
> On Tue, Dec 10, 2013 at 08:32:38AM -0800, H. Peter Anvin wrote:
>> Of course it isn't.
> 
> I am not sure what are you trying to say. This is too brief.
> 
> Thanks
> Vivek
> 

Of course it is not sufficient.  Once you can get arbitrary code into
kernel space (CPL 0) you can do anything, and "disabling jump back" is
just a speed bump.

	-hpa



  reply	other threads:[~2013-12-10 18:55 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-10  0:16 [PATCH v2] kexec: add sysctl to disable kexec Kees Cook
2013-12-10  0:34 ` H. Peter Anvin
2013-12-10  1:06   ` Kees Cook
2013-12-10 14:35     ` Vivek Goyal
2013-12-10 14:38       ` Vivek Goyal
2013-12-10 16:32       ` H. Peter Anvin
2013-12-10 18:33         ` Vivek Goyal
2013-12-10 18:54           ` H. Peter Anvin [this message]
2013-12-10 19:14             ` Vivek Goyal
2013-12-10 19:33               ` Kees Cook
2013-12-11 17:52 ` Eric W. Biederman
2013-12-11 21:13   ` Kees Cook
2013-12-11 23:15     ` Eric W. Biederman
2013-12-11 23:22       ` Kees Cook
2013-12-12  1:14         ` Eric W. Biederman

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