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=-16.8 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 59F71C43460 for ; Tue, 27 Apr 2021 20:44:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 364FD61420 for ; Tue, 27 Apr 2021 20:44:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239046AbhD0UpH (ORCPT ); Tue, 27 Apr 2021 16:45:07 -0400 Received: from mga05.intel.com ([192.55.52.43]:31779 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239038AbhD0Uow (ORCPT ); Tue, 27 Apr 2021 16:44:52 -0400 IronPort-SDR: 0vx8tUf41OlnCihQhl1GQVjY2f9JPPYzlCxF5a6wiABAOpdOau3SBF/3siDJKsrS3LYKY/ofO7 RDNg+MCZn+mQ== X-IronPort-AV: E=McAfee;i="6200,9189,9967"; a="281922446" X-IronPort-AV: E=Sophos;i="5.82,255,1613462400"; d="scan'208";a="281922446" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Apr 2021 13:44:07 -0700 IronPort-SDR: 7P8jTrq4zYxq3ucQoaAPWtoyBHLoKd1I1fXA8lTvxqFOvUSMbpYdEh7z1PHiAdeYJM27K219Id VJ/nB5nqJdKQ== X-IronPort-AV: E=Sophos;i="5.82,255,1613462400"; d="scan'208";a="465623429" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Apr 2021 13:44:06 -0700 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 , Haitao Huang Cc: Yu-cheng Yu Subject: [PATCH v26 02/30] x86/cet/shstk: Add Kconfig option for Shadow Stack Date: Tue, 27 Apr 2021 13:42:47 -0700 Message-Id: <20210427204315.24153-3-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210427204315.24153-1-yu-cheng.yu@intel.com> References: <20210427204315.24153-1-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_SHADOW_STACK enabled, 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 Cc: Kees Cook --- v25: - Remove X86_CET and use X86_SHADOW_STACK directly. v24: - Update for the splitting X86_CET to X86_SHADOW_STACK and X86_IBT. 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 2792879d398e..41283f82fd87 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -28,6 +28,7 @@ config X86_64 select ARCH_HAS_GIGANTIC_PAGE select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 select ARCH_USE_CMPXCHG_LOCKREF + select ARCH_HAS_SHADOW_STACK select HAVE_ARCH_SOFT_DIRTY select MODULES_USE_ELF_RELA select NEED_DMA_MAP_STATE @@ -1941,6 +1942,27 @@ config X86_SGX If unsure, say N. +config ARCH_HAS_SHADOW_STACK + def_bool n + +config X86_SHADOW_STACK + prompt "Intel Shadow Stack" + def_bool n + depends on AS_WRUSS + depends on ARCH_HAS_SHADOW_STACK + select ARCH_USES_HIGH_VMA_FLAGS + help + Shadow Stack protection is a hardware feature that detects function + return address corruption. This helps mitigate ROP attacks. + Applications must be enabled to use it, and old userspace does not + get protection "for free". + Support for this feature is present on Tiger Lake family of + 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