From patchwork Mon Nov 29 18:19:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 519034 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB088C433FE for ; Mon, 29 Nov 2021 18:35:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353411AbhK2Siq (ORCPT ); Mon, 29 Nov 2021 13:38:46 -0500 Received: from sin.source.kernel.org ([145.40.73.55]:53618 "EHLO sin.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379013AbhK2Sge (ORCPT ); Mon, 29 Nov 2021 13:36:34 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id D3D3FCE157F; Mon, 29 Nov 2021 18:33:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82271C53FD0; Mon, 29 Nov 2021 18:33:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1638210793; bh=Zb8ifKlzWNXeZ8yM4Hq0X0BJEtNmuR1DIE0wPXoNHKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IU8m9iPSfqjgn1VYbYN8N79erTagOOoTCvRIgGtjZaxR7dMvDPlHQG1uvGNQY7jHO b79POLbJqOMnddQuzer7Ns4gSosgmtnkBKJr/WHkPYfLx8rqiEWmkULDLXM4/kaxJV 9CbQnSl6/jPIZuYafVaE6HWSLPTE2wroYhXi+290= 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 Subject: [PATCH 5.10 118/121] s390/mm: validate VMA in PGSTE manipulation functions Date: Mon, 29 Nov 2021 19:19:09 +0100 Message-Id: <20211129181715.636136621@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211129181711.642046348@linuxfoundation.org> References: <20211129181711.642046348@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: David Hildenbrand commit fe3d10024073f06f04c74b9674bd71ccc1d787cf upstream. 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: Greg Kroah-Hartman --- arch/s390/mm/pgtable.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- 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 WARN_ON_ONCE(orc > ESSA_MAX); if (unlikely(orc > ESSA_MAX)) return -EINVAL; + + vma = find_vma(mm, hva); + if (!vma || hva < vma->vm_start || 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 = find_vma(mm, hva); + if (!vma || hva < vma->vm_start || 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 = find_vma(mm, hva); + if (!vma || hva < vma->vm_start || is_vm_hugetlb_page(vma)) + return -EFAULT; ptep = get_locked_pte(mm, hva, &ptl); if (unlikely(!ptep)) return -EFAULT;