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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 861BAC8300B for ; Wed, 29 Apr 2020 22:10:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C4DE2076B for ; Wed, 29 Apr 2020 22:10:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727028AbgD2WKa (ORCPT ); Wed, 29 Apr 2020 18:10:30 -0400 Received: from mga09.intel.com ([134.134.136.24]:61292 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727830AbgD2WIm (ORCPT ); Wed, 29 Apr 2020 18:08:42 -0400 IronPort-SDR: 0K+ydWruisOHemTRClejmqu5W3mw9FdKTTDtufQ2hz112oFVkSH74KpRnBANpl2vH9L/ciKqv2 I+HfjPw6e4Bw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2020 15:08:42 -0700 IronPort-SDR: rkCyd4MEbRBcVRLk9asgG/r/BHUdH6pFX5SaolLMaG4cC/bBBEq2dq4lza1tP+mjdFUUotFfrD 4cfGOnyZcUDA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,333,1583222400"; d="scan'208";a="276308861" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga002.jf.intel.com with ESMTP; 29 Apr 2020 15:08:41 -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 Cc: Yu-cheng Yu Subject: [PATCH v10 05/26] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack Date: Wed, 29 Apr 2020 15:07:11 -0700 Message-Id: <20200429220732.31602-6-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200429220732.31602-1-yu-cheng.yu@intel.com> References: <20200429220732.31602-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@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_INTEL_SHADOW_STACK_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 --- v10: - Change SHSTK to shadow stack in the help text. - Change build-time check to config-time check. - Change ARCH_HAS_SHSTK to ARCH_HAS_SHADOW_STACK. arch/x86/Kconfig | 30 +++++++++++++++++++++++++++ scripts/as-x86_64-has-shadow-stack.sh | 4 ++++ 2 files changed, 34 insertions(+) create mode 100755 scripts/as-x86_64-has-shadow-stack.sh diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 1197b5596d5a..c98f82fffe85 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1947,6 +1947,36 @@ config X86_INTEL_TSX_MODE_AUTO side channel attacks- equals the tsx=auto command line parameter. endchoice +config AS_HAS_SHADOW_STACK + def_bool $(success,$(srctree)/scripts/as-x86_64-has-shadow-stack.sh $(CC)) + help + Test the assembler for shadow stack instructions. + +config X86_INTEL_CET + def_bool n + +config ARCH_HAS_SHADOW_STACK + def_bool n + +config X86_INTEL_SHADOW_STACK_USER + prompt "Intel Shadow Stacks for user-mode" + def_bool n + depends on CPU_SUP_INTEL && X86_64 + depends on AS_HAS_SHADOW_STACK + select ARCH_USES_HIGH_VMA_FLAGS + select X86_INTEL_CET + select ARCH_HAS_SHADOW_STACK + help + Shadow Stacks provides protection against program stack + corruption. It's a hardware feature. This only matters + if you have the right hardware. It's a security hardening + feature and apps must be enabled to use it. You get no + protection "for free" on old userspace. The hardware can + support user and kernel, but this option is for user space + only. + + If unsure, say y. + config EFI bool "EFI runtime service support" depends on ACPI diff --git a/scripts/as-x86_64-has-shadow-stack.sh b/scripts/as-x86_64-has-shadow-stack.sh new file mode 100755 index 000000000000..fac1d363a1b8 --- /dev/null +++ b/scripts/as-x86_64-has-shadow-stack.sh @@ -0,0 +1,4 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +echo "wrussq %rax, (%rbx)" | $* -x assembler -c - -- 2.21.0