From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 32E697D062 for ; Thu, 7 Jun 2018 15:47:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934072AbeFGPqb (ORCPT ); Thu, 7 Jun 2018 11:46:31 -0400 Received: from mga09.intel.com ([134.134.136.24]:36282 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934269AbeFGOkd (ORCPT ); Thu, 7 Jun 2018 10:40:33 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Jun 2018 07:40:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,486,1520924400"; d="scan'208";a="47542289" Received: from 2b52.sc.intel.com ([143.183.136.51]) by orsmga008.jf.intel.com with ESMTP; 07 Jun 2018 07:40:31 -0700 From: Yu-cheng Yu To: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , "H.J. Lu" , Vedvyas Shanbhogue , "Ravi V. Shankar" , Dave Hansen , Andy Lutomirski , Jonathan Corbet , Oleg Nesterov , Arnd Bergmann , Mike Kravetz Cc: Yu-cheng Yu Subject: [PATCH 2/9] x86/cet: Add Kconfig option for user-mode shadow stack Date: Thu, 7 Jun 2018 07:36:58 -0700 Message-Id: <20180607143705.3531-3-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180607143705.3531-1-yu-cheng.yu@intel.com> References: <20180607143705.3531-1-yu-cheng.yu@intel.com> Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Introduce Kconfig option X86_INTEL_SHADOW_STACK_USER. An application has shadow stack protection when all the following are true: (1) The kernel has X86_INTEL_SHADOW_STACK_USER enabled, (2) The running processor supports the shadow stack, (3) The application is built with shadow stack enabled tools & libs and, and at runtime, all dependent shared libs can support shadow stack. If this kernel config option is enabled, but (2) or (3) above is not true, the application runs without the shadow stack protection. Existing legacy applications will continue to work without the shadow stack protection. The user-mode shadow stack protection is only implemented for the 64-bit kernel. Thirty-two bit applications are supported under the compatibility mode. Signed-off-by: Yu-cheng Yu --- arch/x86/Kconfig | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c07f492b871a..dd580d4910fc 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1925,6 +1925,30 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS If unsure, say y. +config X86_INTEL_CET + def_bool n + +config ARCH_HAS_SHSTK + def_bool n + +config X86_INTEL_SHADOW_STACK_USER + prompt "Intel Shadow Stack for user-mode" + def_bool n + depends on CPU_SUP_INTEL && X86_64 + select X86_INTEL_CET + select ARCH_HAS_SHSTK + ---help--- + Shadow stack provides hardware protection against program stack + corruption. Only when all the following are true will an application + have the shadow stack protection: the kernel supports it (i.e. this + feature is enabled), the application is compiled and linked with + shadow stack enabled, and the processor supports this feature. + When the kernel has this configuration enabled, existing non shadow + stack applications will continue to work, but without shadow stack + protection. + + If unsure, say y. + config EFI bool "EFI runtime service support" depends on ACPI -- 2.15.1 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html