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_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 2ABB8C4BA26 for ; Wed, 26 Feb 2020 19:57:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 091B4222C4 for ; Wed, 26 Feb 2020 19:57:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727312AbgBZT5O (ORCPT ); Wed, 26 Feb 2020 14:57:14 -0500 Received: from jabberwock.ucw.cz ([46.255.230.98]:54622 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727244AbgBZT5N (ORCPT ); Wed, 26 Feb 2020 14:57:13 -0500 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id C1A811C036E; Wed, 26 Feb 2020 20:57:10 +0100 (CET) Date: Wed, 26 Feb 2020 20:57:10 +0100 From: Pavel Machek To: Dave Hansen Cc: Yu-cheng Yu , x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , x86-patch-review@intel.com Subject: Re: [RFC PATCH v9 05/27] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack protection Message-ID: <20200226195710.6sma4whvs3o76oux@ucw.cz> References: <20200205181935.3712-1-yu-cheng.yu@intel.com> <20200205181935.3712-6-yu-cheng.yu@intel.com> <597fb45a-cb94-e8e7-8e80-45a26766d32a@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <597fb45a-cb94-e8e7-8e80-45a26766d32a@intel.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On 2/5/20 10:19 AM, Yu-cheng Yu wrote: > > Introduce Kconfig option: X86_INTEL_SHADOW_STACK_USER. > > > > Shadow Stack (SHSTK) provides protection against function return address > > corruption. It is active when the kernel has this feature enabled, and > > both the processor and the application support it. When this feature is > > enabled, legacy non-SHSTK applications continue to work, but without SHSTK > > protection. > > > > The user-mode SHSTK protection is only implemented for the 64-bit kernel. > > IA32 applications are supported under the compatibility mode. > > I think what you're trying to say here is that the hardware supports > shadow stacks with 32-bit kernels. However, this series does not > include that support and we have no plans to add it. > > Right? > > I'll let others weigh in, but I rather dislike the use of acronyms here. > I'd much rather see the english "shadow stack" everywhere than SHSTK. For the record, I like "shadow stack" better, too. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [RFC PATCH v9 05/27] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack protection Date: Wed, 26 Feb 2020 20:57:10 +0100 Message-ID: <20200226195710.6sma4whvs3o76oux@ucw.cz> References: <20200205181935.3712-1-yu-cheng.yu@intel.com> <20200205181935.3712-6-yu-cheng.yu@intel.com> <597fb45a-cb94-e8e7-8e80-45a26766d32a@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <597fb45a-cb94-e8e7-8e80-45a26766d32a@intel.com> Sender: linux-doc-owner@vger.kernel.org To: Dave Hansen Cc: Yu-cheng Yu , x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz List-Id: linux-arch.vger.kernel.org > On 2/5/20 10:19 AM, Yu-cheng Yu wrote: > > Introduce Kconfig option: X86_INTEL_SHADOW_STACK_USER. > > > > Shadow Stack (SHSTK) provides protection against function return address > > corruption. It is active when the kernel has this feature enabled, and > > both the processor and the application support it. When this feature is > > enabled, legacy non-SHSTK applications continue to work, but without SHSTK > > protection. > > > > The user-mode SHSTK protection is only implemented for the 64-bit kernel. > > IA32 applications are supported under the compatibility mode. > > I think what you're trying to say here is that the hardware supports > shadow stacks with 32-bit kernels. However, this series does not > include that support and we have no plans to add it. > > Right? > > I'll let others weigh in, but I rather dislike the use of acronyms here. > I'd much rather see the english "shadow stack" everywhere than SHSTK. For the record, I like "shadow stack" better, too.