From patchwork Wed Feb 3 22:55:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu-cheng Yu X-Patchwork-Id: 12065645 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 2A1EAC433E0 for ; Wed, 3 Feb 2021 22:56:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B15E164E38 for ; Wed, 3 Feb 2021 22:56:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B15E164E38 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 265568D0008; Wed, 3 Feb 2021 17:56:33 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 217C48D0007; Wed, 3 Feb 2021 17:56:33 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0DE898D0008; Wed, 3 Feb 2021 17:56:33 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0140.hostedemail.com [216.40.44.140]) by kanga.kvack.org (Postfix) with ESMTP id DE4B48D0007 for ; Wed, 3 Feb 2021 17:56:32 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id A8F05362D for ; Wed, 3 Feb 2021 22:56:32 +0000 (UTC) X-FDA: 77778467424.16.fifth72_1114f48275d7 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin16.hostedemail.com (Postfix) with ESMTP id 835BD100E690B for ; Wed, 3 Feb 2021 22:56:32 +0000 (UTC) X-HE-Tag: fifth72_1114f48275d7 X-Filterd-Recvd-Size: 5585 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by imf04.hostedemail.com (Postfix) with ESMTP for ; Wed, 3 Feb 2021 22:56:31 +0000 (UTC) IronPort-SDR: WtpdlT0M36bCJMEdk6lUNv6bTsWLST/UM48QFI2A1MYp1gjtPA3dvmcXLjJ8UNlefpPs8tnLAI BvIbV9lfpODQ== X-IronPort-AV: E=McAfee;i="6000,8403,9884"; a="200102482" X-IronPort-AV: E=Sophos;i="5.79,399,1602572400"; d="scan'208";a="200102482" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2021 14:56:30 -0800 IronPort-SDR: ZATXDVE4oU1cXivQHr/R3pV/sj5RxVs6GFYbtgGXsSadbA/fwUasLyOAJAL1Ug6JaHRqiOs94L gwGHC490f+0g== X-IronPort-AV: E=Sophos;i="5.79,399,1602572400"; d="scan'208";a="507921140" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2021 14:56:30 -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 v19 18/25] mm: Update can_follow_write_pte() for shadow stack Date: Wed, 3 Feb 2021 14:55:40 -0800 Message-Id: <20210203225547.32221-19-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20210203225547.32221-1-yu-cheng.yu@intel.com> References: <20210203225547.32221-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 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: Can_follow_write_pte() ensures a read-only page is COWed by checking the FOLL_COW flag, and uses pte_dirty() to validate the flag is still valid. Like a writable data page, a shadow stack page is writable, and becomes read-only during copy-on-write, but it is always dirty. Thus, in the can_follow_write_pte() check, it belongs to the writable page case and should be excluded from the read-only page pte_dirty() check. Apply the same changes to can_follow_write_pmd(). Signed-off-by: Yu-cheng Yu Reviewed-by: Kees Cook --- mm/gup.c | 8 +++++--- mm/huge_memory.c | 8 +++++--- 2 files changed, 10 insertions(+), 6 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index e4c224cd9661..66ab67626f57 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -357,10 +357,12 @@ static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address, * FOLL_FORCE can write to even unwritable pte's, but only * after we've gone through a COW cycle and they are dirty. */ -static inline bool can_follow_write_pte(pte_t pte, unsigned int flags) +static inline bool can_follow_write_pte(pte_t pte, unsigned int flags, + struct vm_area_struct *vma) { return pte_write(pte) || - ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte)); + ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte) && + !arch_shadow_stack_mapping(vma->vm_flags)); } static struct page *follow_page_pte(struct vm_area_struct *vma, @@ -403,7 +405,7 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, } if ((flags & FOLL_NUMA) && pte_protnone(pte)) goto no_page; - if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags)) { + if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags, vma)) { pte_unmap_unlock(ptep, ptl); return NULL; } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index bfec65c9308b..eb64e2b56bc9 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1337,10 +1337,12 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) * FOLL_FORCE can write to even unwritable pmd's, but only * after we've gone through a COW cycle and they are dirty. */ -static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) +static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags, + struct vm_area_struct *vma) { return pmd_write(pmd) || - ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); + ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd) && + !arch_shadow_stack_mapping(vma->vm_flags)); } struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, @@ -1353,7 +1355,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, assert_spin_locked(pmd_lockptr(mm, pmd)); - if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) + if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags, vma)) goto out; /* Avoid dumping huge zero page */