From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10A37ECE563 for ; Mon, 17 Sep 2018 17:13:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB576214D5 for ; Mon, 17 Sep 2018 17:13:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB576214D5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727864AbeIQWlm (ORCPT ); Mon, 17 Sep 2018 18:41:42 -0400 Received: from gate.crashing.org ([63.228.1.57]:38904 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726795AbeIQWll (ORCPT ); Mon, 17 Sep 2018 18:41:41 -0400 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id w8HGkF8v007790; Mon, 17 Sep 2018 11:46:15 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id w8HGkDal007780; Mon, 17 Sep 2018 11:46:13 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 17 Sep 2018 11:46:13 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] powerpc: initial stack protector (-fstack-protector) support Message-ID: <20180917164613.GJ23155@gate.crashing.org> References: <9f7efcc085685717bb4c7b3a575138a1a1cd15ed.1537186089.git.christophe.leroy@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9f7efcc085685717bb4c7b3a575138a1a1cd15ed.1537186089.git.christophe.leroy@c-s.fr> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! On Mon, Sep 17, 2018 at 12:15:05PM +0000, Christophe Leroy wrote: > Now, GCC offers the possibility to manually set the > stack-protector mode (global or tls) regardless of libc support. Yup :-) > This time, the patch selects HAVE_STACKPROTECTOR only if > -mstack-protector-guard=global is supported by GCC. "global" is weaker than "tls" (it is easier to read the cookie in an exploit). It is better to use tls if you can. Segher