From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752084AbcEKWlD (ORCPT ); Wed, 11 May 2016 18:41:03 -0400 Received: from mga04.intel.com ([192.55.52.120]:44519 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751562AbcEKWlB (ORCPT ); Wed, 11 May 2016 18:41:01 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,609,1455004800"; d="scan'208";a="977895770" Date: Wed, 11 May 2016 15:40:58 -0700 From: Andi Kleen To: Kees Cook Cc: Hector Marco-Gisbert , Andy Lutomirski , LKML , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "x86@kernel.org" , Brian Gerst , Borislav Petkov , Huaitong Han , Ismael Ripoll Ripoll Subject: Re: [PATCH] x86_64: Disabling read-implies-exec when the stack is executable Message-ID: <20160511224058.GL11177@tassilo.jf.intel.com> References: <1462963502-11636-1-git-send-email-hecmargi@upv.es> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > However, I would tend to agree: RIE should only be needed on 32-bit > since 64-bit started its life knowing about no-exec permissions. NX was not in the original AMD K8 chips. Was only added some time later. > set_personality_64bit()'s (which is confusingly just an initializer > and not called during the personality() syscall) comment about this > makes no sense to me: > > /* TBD: overwrites user setup. Should have two bits. > But 64bit processes have always behaved this way, > so it's not too bad. The main problem is just that > 32bit childs are affected again. */ > current->personality &= ~READ_IMPLIES_EXEC; What does not make sense? -Andi