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=-16.7 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 362E7C433E0 for ; Wed, 27 Jan 2021 21:26:48 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DD58360C3F for ; Wed, 27 Jan 2021 21:26:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DD58360C3F 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 B213E8D0006; Wed, 27 Jan 2021 16:26:29 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AAE058D0007; Wed, 27 Jan 2021 16:26:29 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8D89D8D0006; Wed, 27 Jan 2021 16:26:29 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0029.hostedemail.com [216.40.44.29]) by kanga.kvack.org (Postfix) with ESMTP id 71E448D0001 for ; Wed, 27 Jan 2021 16:26:29 -0500 (EST) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 30E5E181AEF21 for ; Wed, 27 Jan 2021 21:26:29 +0000 (UTC) X-FDA: 77752838898.01.dad71_3d156e22759a Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin01.hostedemail.com (Postfix) with ESMTP id F035A1004EC44 for ; Wed, 27 Jan 2021 21:26:02 +0000 (UTC) X-HE-Tag: dad71_3d156e22759a X-Filterd-Recvd-Size: 6699 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf15.hostedemail.com (Postfix) with ESMTP for ; Wed, 27 Jan 2021 21:26:01 +0000 (UTC) IronPort-SDR: e7I7knhtrEdnVjczzHVcAoJOolZD6QqeQv7voPR0axIuJ8wicG4gkj8+ix/C6c/1g7EGa8CO1b GkhF7BDfZ8fQ== X-IronPort-AV: E=McAfee;i="6000,8403,9877"; a="180281150" X-IronPort-AV: E=Sophos;i="5.79,380,1602572400"; d="scan'208";a="180281150" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jan 2021 13:25:56 -0800 IronPort-SDR: A4Gcmb38MdT1UtYNYrK/Hp2wjJ6uWqJg0pZpdbMY/drs4r78YatA6pcAPC9xD8NnO0I0Jw2zr3 6zHJCQPOLDBg== X-IronPort-AV: E=Sophos;i="5.79,380,1602572400"; d="scan'208";a="353948232" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jan 2021 13:25:56 -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 v18 14/25] x86/mm: Update maybe_mkwrite() for shadow stack Date: Wed, 27 Jan 2021 13:25:13 -0800 Message-Id: <20210127212524.10188-15-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210127212524.10188-1-yu-cheng.yu@intel.com> References: <20210127212524.10188-1-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: When serving a page fault, maybe_mkwrite() makes a PTE writable if its vm= a has VM_WRITE. A shadow stack vma has VM_SHSTK. Its PTEs have _PAGE_DIRTY, but not _PAGE_WRITE. In fork(), _PAGE_DIRTY is cleared to effect copy-on-write, and in page fault, _PAGE_DIRTY is restored and the shadow stack page is writable again. Update maybe_mkwrite() by introducing arch_maybe_mkwrite(), which sets _PAGE_DIRTY for a shadow stack PTE. Apply the same changes to maybe_pmd_mkwrite(). Signed-off-by: Yu-cheng Yu --- arch/x86/Kconfig | 4 ++++ arch/x86/mm/pgtable.c | 18 ++++++++++++++++++ include/linux/mm.h | 2 ++ include/linux/pgtable.h | 24 ++++++++++++++++++++++++ mm/huge_memory.c | 2 ++ 5 files changed, 50 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2d080a2335df..1204a6dcc0da 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1954,6 +1954,9 @@ config X86_SGX config ARCH_HAS_SHADOW_STACK def_bool n =20 +config ARCH_MAYBE_MKWRITE + def_bool n + config X86_CET prompt "Intel Control-flow protection for user-mode" def_bool n @@ -1961,6 +1964,7 @@ config X86_CET depends on AS_WRUSS select ARCH_USES_HIGH_VMA_FLAGS select ARCH_HAS_SHADOW_STACK + select ARCH_MAYBE_MKWRITE help Control-flow protection is a hardware security hardening feature that detects function-return address or jump target changes by diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index f6a9e2e36642..0f4fbf51a9fc 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -610,6 +610,24 @@ int pmdp_clear_flush_young(struct vm_area_struct *vm= a, } #endif =20 +#ifdef CONFIG_ARCH_MAYBE_MKWRITE +pte_t arch_maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) +{ + if (likely(vma->vm_flags & VM_SHSTK)) + pte =3D pte_mkwrite_shstk(pte); + return pte; +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +pmd_t arch_maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) +{ + if (likely(vma->vm_flags & VM_SHSTK)) + pmd =3D pmd_mkwrite_shstk(pmd); + return pmd; +} +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ +#endif /* CONFIG_ARCH_MAYBE_MKWRITE */ + /** * reserve_top_address - reserves a hole in the top of kernel address sp= ace * @reserve - size of hole to reserve diff --git a/include/linux/mm.h b/include/linux/mm.h index 7be5f8b874aa..abd756e426fc 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -993,6 +993,8 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct v= m_area_struct *vma) { if (likely(vma->vm_flags & VM_WRITE)) pte =3D pte_mkwrite(pte); + else + pte =3D arch_maybe_mkwrite(pte, vma); return pte; } =20 diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 8fcdfa52eb4b..d8452218d09b 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1439,6 +1439,30 @@ static inline bool arch_has_pfn_modify_check(void) } #endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */ =20 +#ifdef CONFIG_MMU +#ifdef CONFIG_ARCH_MAYBE_MKWRITE +pte_t arch_maybe_mkwrite(pte_t pte, struct vm_area_struct *vma); + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +pmd_t arch_maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma); +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + +#else /* !CONFIG_ARCH_MAYBE_MKWRITE */ +static inline pte_t arch_maybe_mkwrite(pte_t pte, struct vm_area_struct = *vma) +{ + return pte; +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +static inline pmd_t arch_maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_str= uct *vma) +{ + return pmd; +} +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + +#endif /* CONFIG_ARCH_MAYBE_MKWRITE */ +#endif /* CONFIG_MMU */ + /* * Architecture PAGE_KERNEL_* fallbacks * diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9237976abe72..bfec65c9308b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -478,6 +478,8 @@ pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_str= uct *vma) { if (likely(vma->vm_flags & VM_WRITE)) pmd =3D pmd_mkwrite(pmd); + else + pmd =3D arch_maybe_pmd_mkwrite(pmd, vma); return pmd; } =20 --=20 2.21.0