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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17D1EC43219 for ; Tue, 16 Nov 2021 01:26:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04FC063259 for ; Tue, 16 Nov 2021 01:26:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380556AbhKPB27 (ORCPT ); Mon, 15 Nov 2021 20:28:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:34524 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243664AbhKOTCQ (ORCPT ); Mon, 15 Nov 2021 14:02:16 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DF50F63354; Mon, 15 Nov 2021 18:14:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637000084; bh=u/A7qNJqw2HYjZOMQugM6KVKv8N+Kb0hobvc7LRX6qQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YclwjgyfT1HL2SuEW0lLPlBHhwHFsOicPYCIy7yyQ5VocLbzPFENmDNMqe5JIkRfo VFk3xRYeXwRjlJH3eZEpfAVi4O9I/FdUGdoeHt1HRgN19Ca+Gtg/KbjrGFC5XYN6cU ZEVL6R4MLs1mnO1hk6kdCdVFc+AllJuK9fySmfsE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Hildenbrand , Claudio Imbrenda , Heiko Carstens , Christian Borntraeger , Sasha Levin Subject: [PATCH 5.14 499/849] s390/mm: validate VMA in PGSTE manipulation functions Date: Mon, 15 Nov 2021 17:59:42 +0100 Message-Id: <20211115165437.156257690@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165419.961798833@linuxfoundation.org> References: <20211115165419.961798833@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Hildenbrand [ Upstream commit fe3d10024073f06f04c74b9674bd71ccc1d787cf ] We should not walk/touch page tables outside of VMA boundaries when holding only the mmap sem in read mode. Evil user space can modify the VMA layout just before this function runs and e.g., trigger races with page table removal code since commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap"). gfn_to_hva() will only translate using KVM memory regions, but won't validate the VMA. Further, we should not allocate page tables outside of VMA boundaries: if evil user space decides to map hugetlbfs to these ranges, bad things will happen because we suddenly have PTE or PMD page tables where we shouldn't have them. Similarly, we have to check if we suddenly find a hugetlbfs VMA, before calling get_locked_pte(). Fixes: 2d42f9477320 ("s390/kvm: Add PGSTE manipulation functions") Signed-off-by: David Hildenbrand Reviewed-by: Claudio Imbrenda Acked-by: Heiko Carstens Link: https://lore.kernel.org/r/20210909162248.14969-4-david@redhat.com Signed-off-by: Christian Borntraeger Signed-off-by: Sasha Levin --- arch/s390/mm/pgtable.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index eec3a9d7176e3..54969e0f3a944 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -988,6 +988,7 @@ EXPORT_SYMBOL(get_guest_storage_key); int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc, unsigned long *oldpte, unsigned long *oldpgste) { + struct vm_area_struct *vma; unsigned long pgstev; spinlock_t *ptl; pgste_t pgste; @@ -997,6 +998,10 @@ int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc, WARN_ON_ONCE(orc > ESSA_MAX); if (unlikely(orc > ESSA_MAX)) return -EINVAL; + + vma = vma_lookup(mm, hva); + if (!vma || is_vm_hugetlb_page(vma)) + return -EFAULT; ptep = get_locked_pte(mm, hva, &ptl); if (unlikely(!ptep)) return -EFAULT; @@ -1089,10 +1094,14 @@ EXPORT_SYMBOL(pgste_perform_essa); int set_pgste_bits(struct mm_struct *mm, unsigned long hva, unsigned long bits, unsigned long value) { + struct vm_area_struct *vma; spinlock_t *ptl; pgste_t new; pte_t *ptep; + vma = vma_lookup(mm, hva); + if (!vma || is_vm_hugetlb_page(vma)) + return -EFAULT; ptep = get_locked_pte(mm, hva, &ptl); if (unlikely(!ptep)) return -EFAULT; @@ -1117,9 +1126,13 @@ EXPORT_SYMBOL(set_pgste_bits); */ int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep) { + struct vm_area_struct *vma; spinlock_t *ptl; pte_t *ptep; + vma = vma_lookup(mm, hva); + if (!vma || is_vm_hugetlb_page(vma)) + return -EFAULT; ptep = get_locked_pte(mm, hva, &ptl); if (unlikely(!ptep)) return -EFAULT; -- 2.33.0