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=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 31DA7C433E0 for ; Wed, 10 Feb 2021 17:58:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C2BD564ED4 for ; Wed, 10 Feb 2021 17:58:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C2BD564ED4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 565C88D0005; Wed, 10 Feb 2021 12:58:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 479E08D0002; Wed, 10 Feb 2021 12:58:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 16D7E8D0003; Wed, 10 Feb 2021 12:58:08 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0092.hostedemail.com [216.40.44.92]) by kanga.kvack.org (Postfix) with ESMTP id B8B7A6B0080 for ; Wed, 10 Feb 2021 12:58:08 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 8466110FD5 for ; Wed, 10 Feb 2021 17:58:08 +0000 (UTC) X-FDA: 77803117056.29.sign65_200ac2527611 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 5B074183084B8 for ; Wed, 10 Feb 2021 17:58:08 +0000 (UTC) X-HE-Tag: sign65_200ac2527611 X-Filterd-Recvd-Size: 5778 Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Wed, 10 Feb 2021 17:58:07 +0000 (UTC) IronPort-SDR: 9cBaH/SjwbsvVyWwnl5U3IGXwwAv5tH4jzOrIKYWa1vqW02irYDfXkTlqQY95V6d7y2JAloUfq S1MRrdpSvksw== X-IronPort-AV: E=McAfee;i="6000,8403,9891"; a="243612381" X-IronPort-AV: E=Sophos;i="5.81,168,1610438400"; d="scan'208";a="243612381" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Feb 2021 09:58:02 -0800 IronPort-SDR: C35DMy/+nTMK4JMfi0VvgG7UCB4xKNTSSpzzRHsvZ0kIrvWnUniKjfiI/at6SCEd/LI0OndhjT JBOglZypVAAg== X-IronPort-AV: E=Sophos;i="5.81,168,1610438400"; d="scan'208";a="421140757" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Feb 2021 09:58:01 -0800 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 v20 12/25] mm: Introduce VM_SHSTK for shadow stack memory Date: Wed, 10 Feb 2021 09:56:50 -0800 Message-Id: <20210210175703.12492-13-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210210175703.12492-1-yu-cheng.yu@intel.com> References: <20210210175703.12492-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 --- Documentation/filesystems/proc.rst | 1 + arch/x86/mm/mmap.c | 2 ++ fs/proc/task_mmu.c | 3 +++ include/linux/mm.h | 8 ++++++++ 4 files changed, 14 insertions(+) diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesyste= ms/proc.rst index 2fa69f710e2a..fc533bfb9391 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -549,6 +549,7 @@ encoded manner. The codes are the following: mg mergable advise flag bt arm64 BTI guarded page mt arm64 MTE allocation tags are enabled + ss shadow stack page =3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 Note that there is no guarantee that every flag and associated mnemonic = will 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) =20 const char *arch_vma_name(struct vm_area_struct *vma) { + if (vma->vm_flags & VM_SHSTK) + return "[shadow stack]"; return NULL; } =20 diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 602e3a52884d..59623dcd92bb 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -661,6 +661,9 @@ static void show_smap_vma_flags(struct seq_file *m, s= truct vm_area_struct *vma) [ilog2(VM_PKEY_BIT4)] =3D "", #endif #endif /* CONFIG_ARCH_HAS_PKEYS */ +#ifdef CONFIG_X86_CET + [ilog2(VM_SHSTK)] =3D "ss", +#endif }; size_t i; =20 diff --git a/include/linux/mm.h b/include/linux/mm.h index ecdf8a8cd6ae..7be5f8b874aa 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -312,11 +312,13 @@ 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 */ =20 #ifdef CONFIG_ARCH_HAS_PKEYS @@ -332,6 +334,12 @@ extern unsigned int kobjsize(const void *objp); #endif #endif /* CONFIG_ARCH_HAS_PKEYS */ =20 +#ifdef CONFIG_X86_CET +# 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) --=20 2.21.0