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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 74ABCC2BB9A for ; Wed, 9 Dec 2020 22:24:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 56BB0238A0 for ; Wed, 9 Dec 2020 22:24:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388662AbgLIWYf (ORCPT ); Wed, 9 Dec 2020 17:24:35 -0500 Received: from mga18.intel.com ([134.134.136.126]:14580 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388639AbgLIWYa (ORCPT ); Wed, 9 Dec 2020 17:24:30 -0500 IronPort-SDR: Mx53IUsyXR5JmTKr+ayHHjWStJ8dsZnDVty1g/mNWTeIvxfLduqY0p01+8pK4dG5RWS2RTau6w mGxm/bwMz/FA== X-IronPort-AV: E=McAfee;i="6000,8403,9830"; a="161918055" X-IronPort-AV: E=Sophos;i="5.78,407,1599548400"; d="scan'208";a="161918055" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Dec 2020 14:23:47 -0800 IronPort-SDR: uclimdvVR2tD5wF0nf91TYXck+W/PPf4mnEQLUGLoYy68dqMmFwq7ldTI6YTy1s+ftRXAmW1LR Ir9wdLNWFfEQ== X-IronPort-AV: E=Sophos;i="5.78,407,1599548400"; d="scan'208";a="318543510" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Dec 2020 14:23:46 -0800 From: Yu-cheng Yu To: 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 , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu Cc: Yu-cheng Yu Subject: [PATCH v16 02/26] x86/cet/shstk: Add Kconfig option for user-mode control-flow protection Date: Wed, 9 Dec 2020 14:22:56 -0800 Message-Id: <20201209222320.1724-3-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20201209222320.1724-1-yu-cheng.yu@intel.com> References: <20201209222320.1724-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Shadow Stack provides protection against function return address corruption. It is active when the processor supports it, the kernel has CONFIG_X86_CET_USER, and the application is built for the feature. This is only implemented for the 64-bit kernel. When it is enabled, legacy non-Shadow Stack applications continue to work, but without protection. Signed-off-by: Yu-cheng Yu --- arch/x86/Kconfig | 22 ++++++++++++++++++++++ arch/x86/Kconfig.assembler | 5 +++++ 2 files changed, 27 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index fbf26e0f7a6a..78b4b5bb1272 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1931,6 +1931,28 @@ config X86_INTEL_TSX_MODE_AUTO side channel attacks- equals the tsx=auto command line parameter. endchoice +config ARCH_HAS_SHADOW_STACK + def_bool n + +config X86_CET_USER + prompt "Intel Control-flow protection for user-mode" + def_bool n + depends on CPU_SUP_INTEL && X86_64 + depends on AS_WRUSS + select ARCH_USES_HIGH_VMA_FLAGS + select ARCH_HAS_SHADOW_STACK + help + Control-flow protection is a hardware security hardening feature + that detects function-return address or jump target changes by + malicious code. Applications must be enabled to use it, and old + userspace does not get protection "for free". + Support for this feature is present on processors released in + 2020 or later. Enabling this feature increases kernel text size + by 3.7 KB. + See Documentation/x86/intel_cet.rst for more information. + + If unsure, say N. + config EFI bool "EFI runtime service support" depends on ACPI diff --git a/arch/x86/Kconfig.assembler b/arch/x86/Kconfig.assembler index 26b8c08e2fc4..00c79dd93651 100644 --- a/arch/x86/Kconfig.assembler +++ b/arch/x86/Kconfig.assembler @@ -19,3 +19,8 @@ config AS_TPAUSE def_bool $(as-instr,tpause %ecx) help Supported by binutils >= 2.31.1 and LLVM integrated assembler >= V7 + +config AS_WRUSS + def_bool $(as-instr,wrussq %rax$(comma)(%rbx)) + help + Supported by binutils >= 2.31 and LLVM integrated assembler -- 2.21.0