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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 DCB99C4741F for ; Fri, 25 Sep 2020 15:37:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A182520809 for ; Fri, 25 Sep 2020 15:37:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729275AbgIYPhc (ORCPT ); Fri, 25 Sep 2020 11:37:32 -0400 Received: from mga04.intel.com ([192.55.52.120]:20941 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728858AbgIYPhc (ORCPT ); Fri, 25 Sep 2020 11:37:32 -0400 IronPort-SDR: 20KLv/1wlaBeaZltSAPfT0s5Z8UrRekxjaVvbCc5JJh0KxH3ZaPyKZRyhpW7NnXigzIhpRAG8+ A1rYX4JFq/rQ== X-IronPort-AV: E=McAfee;i="6000,8403,9755"; a="158942298" X-IronPort-AV: E=Sophos;i="5.77,302,1596524400"; d="scan'208";a="158942298" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Sep 2020 07:57:22 -0700 IronPort-SDR: Xn7tOP38aTzxS1F3DgT594Nc5/t0LVjgKiMcYDrlupByZ9U9chgs6eqiGEd6P1jD3DYPb6t+FY EwIB+RHGZh9Q== X-IronPort-AV: E=Sophos;i="5.77,302,1596524400"; d="scan'208";a="487499179" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Sep 2020 07:57:21 -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 Cc: Yu-cheng Yu Subject: [PATCH v13 12/26] mm: Introduce VM_SHSTK for shadow stack memory Date: Fri, 25 Sep 2020 07:56:35 -0700 Message-Id: <20200925145649.5438-13-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200925145649.5438-1-yu-cheng.yu@intel.com> References: <20200925145649.5438-1-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 A Shadow Stack PTE must be read-only and have _PAGE_DIRTY set. However, read-only and Dirty PTEs also exist for copy-on-write (COW) pages. These two cases are handled differently for page faults. Introduce VM_SHSTK to track shadow stack VMAs. Signed-off-by: Yu-cheng Yu Reviewed-by: Kees Cook --- v9: - Add VM_SHSTK case to arch_vma_name(). - Revise the commit log to explain why adding a new VM flag. arch/x86/mm/mmap.c | 2 ++ fs/proc/task_mmu.c | 3 +++ include/linux/mm.h | 8 ++++++++ 3 files changed, 13 insertions(+) diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index c90c20904a60..a22c6b6fc607 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -165,6 +165,8 @@ unsigned long get_mmap_base(int is_legacy) const char *arch_vma_name(struct vm_area_struct *vma) { + if (vma->vm_flags & VM_SHSTK) + return "[shadow stack]"; return NULL; } diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 5066b0251ed8..436dd37f2d4c 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -663,6 +663,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) [ilog2(VM_PKEY_BIT4)] = "", #endif #endif /* CONFIG_ARCH_HAS_PKEYS */ +#ifdef CONFIG_X86_SHADOW_STACK_USER + [ilog2(VM_SHSTK)] = "ss", +#endif }; size_t i; diff --git a/include/linux/mm.h b/include/linux/mm.h index b2f370f0b420..a1d61731d7b4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -304,11 +304,13 @@ extern unsigned int kobjsize(const void *objp); #define VM_HIGH_ARCH_BIT_2 34 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit architectures */ +#define VM_HIGH_ARCH_BIT_5 37 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0) #define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1) #define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2) #define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3) #define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) +#define VM_HIGH_ARCH_5 BIT(VM_HIGH_ARCH_BIT_5) #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ #ifdef CONFIG_ARCH_HAS_PKEYS @@ -324,6 +326,12 @@ extern unsigned int kobjsize(const void *objp); #endif #endif /* CONFIG_ARCH_HAS_PKEYS */ +#ifdef CONFIG_X86_SHADOW_STACK_USER +# define VM_SHSTK VM_HIGH_ARCH_5 +#else +# define VM_SHSTK VM_NONE +#endif + #if defined(CONFIG_X86) # define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ #elif defined(CONFIG_PPC) -- 2.21.0