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=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 5433AC8300C for ; Wed, 29 Apr 2020 22:10:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C5C12076B for ; Wed, 29 Apr 2020 22:10:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727911AbgD2WIs (ORCPT ); Wed, 29 Apr 2020 18:08:48 -0400 Received: from mga09.intel.com ([134.134.136.24]:61302 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727896AbgD2WIr (ORCPT ); Wed, 29 Apr 2020 18:08:47 -0400 IronPort-SDR: UUvmM3xpy9aDLyUK+FUbU8m5LmRF5C4tDpffFqFQDUbboIFBx/W1y5b3s4vuuukvJq1uCt2pRb al4TEsVPFoGA== 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 15:08:46 -0700 IronPort-SDR: 2vxAJGg8O3iygJAHmEigMgsjXjgcykqGrkKoYfSXckrD2HdLJpx0LY/BIdbkyFACvdbjlmETut WX0gWiw++O2A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,333,1583222400"; d="scan'208";a="276308890" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga002.jf.intel.com with ESMTP; 29 Apr 2020 15:08:45 -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 12/26] mm: Introduce VM_SHSTK for shadow stack memory Date: Wed, 29 Apr 2020 15:07:18 -0700 Message-Id: <20200429220732.31602-13-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-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@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 cb91eccc4960..fe77fd6debf1 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -163,6 +163,8 @@ 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 8d382d4ec067..434692759265 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -657,6 +657,9 @@ 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_INTEL_SHADOW_STACK_USER + [ilog2(VM_SHSTK)] = "ss", +#endif }; size_t i; diff --git a/include/linux/mm.h b/include/linux/mm.h index 5a323422d783..54bb4cd9fee8 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -294,11 +294,13 @@ 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 @@ -336,6 +338,12 @@ extern unsigned int kobjsize(const void *objp); # define VM_MPX VM_NONE #endif +#ifdef CONFIG_X86_INTEL_SHADOW_STACK_USER +# define VM_SHSTK VM_HIGH_ARCH_5 +#else +# define VM_SHSTK VM_NONE +#endif + #ifndef VM_GROWSUP # define VM_GROWSUP VM_NONE #endif -- 2.21.0