linux-kernel - Re: [kernel-hardening] [PATCH v7 0/9] x86/mm: memory area address KASLR

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Message-ID: <CAGXu5jKSk9910EiyR1q+UzPst_XeP5_Uyx7Wu3j4+Tnsha70qg@mail.gmail.com>
Date:	Thu, 23 Jun 2016 12:59:07 -0700
From:	Kees Cook <keescook@...omium.org>
To:	Sandy Harris <sandyinchina@...il.com>
Cc:	"kernel-hardening@...ts.openwall.com" 
	<kernel-hardening@...ts.openwall.com>,
	Thomas Garnier <thgarnie@...gle.com>,
	Ingo Molnar <mingo@...nel.org>,
	Andy Lutomirski <luto@...nel.org>,
	"x86@...nel.org" <x86@...nel.org>, Borislav Petkov <bp@...e.de>,
	Baoquan He <bhe@...hat.com>, Yinghai Lu <yinghai@...nel.org>,
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	Matt Fleming <matt@...eblueprint.co.uk>,
	Toshi Kani <toshi.kani@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Dan Williams <dan.j.williams@...el.com>,
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	Xiao Guangrong <guangrong.xiao@...ux.intel.com>,
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	Jonathan Corbet <corbet@....net>,
	"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>
Subject: Re: [kernel-hardening] [PATCH v7 0/9] x86/mm: memory area address KASLR

On Thu, Jun 23, 2016 at 12:45 PM, Sandy Harris <sandyinchina@...il.com> wrote:
> Jason Cooper <jason@...edaemon.net> wrote:
>
>> Modern systems that receive a seed from the bootloader via the
>> random-seed property (typically from the hw-rng) can mix both sources
>> for increased resilience.
>>
>> Unfortunately, I'm not very familiar with the internals of x86
>> bootstrapping.  Could GRUB be scripted to do a similar task?  How would
>> the address and size of the seed be passed to the kernel?  command line?
>
> One suggestion is at:
> http://www.av8n.com/computer/htm/secure-random.htm#sec-boot-image

Interesting! This might pose a problem for signed images, though.
(Actually, for signed arm kernels is the DT signed too? If so, it
would be a similar problem.)

-Kees

-- 
Kees Cook
Chrome OS & Brillo Security