From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752063AbcEQTdf (ORCPT <rfc822;w@1wt.eu>);
	Tue, 17 May 2016 15:33:35 -0400
Received: from terminus.zytor.com ([198.137.202.10]:47204 "EHLO mail.zytor.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1751600AbcEQTdd (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Tue, 17 May 2016 15:33:33 -0400
Subject: Re: [PATCH] x86/boot: Refuse to build with data relocations
To: Kees Cook <keescook@chromium.org>
References: <20160512203104.GA7425@www.outflux.net>
 <B09F32EB-DA6E-4A8C-9C7B-DF99B7A2FC62@zytor.com>
 <CAGXu5jLCfMbGCkPYbLPSHax5-GU65xPpjYTscfSkOmZJEv+jrA@mail.gmail.com>
 <8bc4f1fd-c6f8-4643-becf-4f84be378807@zytor.com>
 <20160516103051.GA11330@gmail.com>
 <CAGXu5jJOnADjRkkC_v3rC3ruFrNxM3s7vG9u4jMnQY=yJUT1kA@mail.gmail.com>
 <3b9c1266-f69b-50e4-36fd-ab3e75875293@zytor.com>
 <CAGXu5jJPMC2EjAB8mc_2edyPcRYRxwUO5_mhd9o=jp4wuz5eQg@mail.gmail.com>
 <4a2a6750-5ee3-4549-a92d-f39a2c0e1aad@zytor.com>
 <CAGXu5j+zVytGCJK8_fnzWMwNT6YA+SdQP=mt5NRfOymzKVpP6Q@mail.gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@suse.de>,
        Baoquan He <bhe@redhat.com>, Yinghai Lu <yinghai@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "x86@kernel.org" <x86@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        "H.J. Lu" <hjl.tools@gmail.com>, Dmitry Vyukov <dvyukov@google.com>,
        LKML <linux-kernel@vger.kernel.org>
From: "H. Peter Anvin" <hpa@zytor.com>
Message-ID: <4db3947b-741f-c3c4-f1f2-ba6d85de9f1c@zytor.com>
Date: Tue, 17 May 2016 12:33:17 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.0
MIME-Version: 1.0
In-Reply-To: <CAGXu5j+zVytGCJK8_fnzWMwNT6YA+SdQP=mt5NRfOymzKVpP6Q@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 05/17/16 12:28, Kees Cook wrote:
>>
>> I think there is something way more subtle going on here, and it bothers
>> me exactly because it is subtle.  It may be that it is OK right now, but
>> there are alarm bells going on all over my brain on this.  I'm going to
>> stare at this for a bit and see if I can make sense of it; but if it
>> turns out that what we have is something really problematic it might be
>> better to apply a big hammer and avoid future breakage once and for all.
> 
> Sounds good. I would just like to decouple this from the KASLR
> improvements. This fragility hasn't changed as a result of that work,
> but I'd really like to have that series put to bed -- I've spent a lot
> of time already cleaning up it and other areas of the compressed
> kernel code. :)
> 

Agreed; this is orthogonal to kASLR.

	-hpa