From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Weinberger Subject: Re: [PATCH v2] all arches, signal: Move restart_block to struct task_struct Date: Tue, 11 Nov 2014 11:52:27 +0100 Message-ID: <5461EA6B.9020305@nod.at> References: <43c88012a4959cd427ab634906e697fbc524e847.1414604015.git.luto@amacapital.net> <20141110.211319.1983610686941713044.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from a.ns.miles-group.at ([95.130.255.143]:65275 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752326AbaKKKwd (ORCPT ); Tue, 11 Nov 2014 05:52:33 -0500 In-Reply-To: <20141110.211319.1983610686941713044.davem@davemloft.net> Sender: linux-arch-owner@vger.kernel.org List-ID: To: David Miller , luto@amacapital.net Cc: tglx@linutronix.de, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-arch@vger.kernel.org, viro@zeniv.linux.org.uk, richard.weinberger@gmail.com, hpa@zytor.com, mingo@kernel.org, keescook@chromium.org Am 11.11.2014 um 03:13 schrieb David Miller: > From: Andy Lutomirski > Date: Mon, 10 Nov 2014 14:03:23 -0800 > >> On Wed, Oct 29, 2014 at 11:12 AM, Thomas Gleixner wrote: >>> On Wed, 29 Oct 2014, Andy Lutomirski wrote: >>> >>>> If an attacker can cause a controlled kernel stack overflow, >>>> overwriting the restart block is a very juicy exploit target. >>>> Moving the restart block to struct task_struct prevents this >>>> exploit. >>>> >>>> Note that there are other fields in thread_info that are also easy >>>> targets, at least on some architectures. >>>> >>>> It's also a decent simplification, since the restart code is more or >>>> less identical on all architectures. >>> >>> I think that's the most important change. Moving common stuff into >>> common code. The side effect of slightly reducing the attack surface >>> is nice, but as Al pointed out not really the big win here. >> >> Having gotten exactly zero feedback from any arch maintainer outside >> of x86, am I supposed to pester people further? > > No objections wrt. sparc and if things break I'll help fix it. Same for UML. Acked-by: Richard Weinberger Thanks, //richard