Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932914AbbLNXrt (ORCPT ); Mon, 14 Dec 2015 18:47:49 -0500 Received: from mail-oi0-f52.google.com ([209.85.218.52]:33886 "EHLO mail-oi0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932197AbbLNXro (ORCPT ); Mon, 14 Dec 2015 18:47:44 -0500 MIME-Version: 1.0 In-Reply-To: <566F5444.7000302@sr71.net> References: <20151214190542.39C4886D@viggo.jf.intel.com> <20151214190632.6A741188@viggo.jf.intel.com> <566F52CE.6080501@sr71.net> <566F5444.7000302@sr71.net> From: Andy Lutomirski Date: Mon, 14 Dec 2015 15:47:24 -0800 Message-ID: Subject: Re: [PATCH 31/32] x86, pkeys: execute-only support To: Dave Hansen Cc: Kees Cook , LKML , Linux-MM , "x86@kernel.org" , Linus Torvalds , Andrew Morton , Dave Hansen Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1086 Lines: 30 On Mon, Dec 14, 2015 at 3:44 PM, Dave Hansen wrote: > On 12/14/2015 03:39 PM, Andy Lutomirski wrote: >>> > Nope. My linker-fu is weak. >>> > >>> > Can we even depend on the linker by itself? Even if the sections were >>> > marked --x, we can't actually use them with those permissions unless we >>> > have protection keys. >>> > >>> > Do we need some special tag on the section to tell the linker to map it >>> > as --x under some conditions and r-x for others? >>> > >> Why? Wouldn't --x just end up acting like r-x if PKRU is absent? > > An app doing --x would expect it to be unreadable. I don't think we can > just silently turn it in to r-x. I don't see why. After all, an app doing --x right now gets rx. An app doing r-- still gets r-x on some systems. --Andy -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/