From patchwork Thu Sep 9 16:22:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 12483425 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 3B56BC433F5 for ; Thu, 9 Sep 2021 16:24:01 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E26A5611CA for ; Thu, 9 Sep 2021 16:24:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E26A5611CA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 10E086B007D; Thu, 9 Sep 2021 12:23:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 096966B007E; Thu, 9 Sep 2021 12:23:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D8EDF900002; Thu, 9 Sep 2021 12:23:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0236.hostedemail.com [216.40.44.236]) by kanga.kvack.org (Postfix) with ESMTP id C4B1B6B007D for ; Thu, 9 Sep 2021 12:23:51 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 6EC0F181CC1A5 for ; Thu, 9 Sep 2021 16:23:51 +0000 (UTC) X-FDA: 78568556262.20.A2545AD Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf26.hostedemail.com (Postfix) with ESMTP id 2326720019DE for ; Thu, 9 Sep 2021 16:23:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1631204630; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Vy4AapnQMIXuIP4+oB7VDWAdrTQvAAS99Uj1TpIfDfo=; b=awbT2nxUK9lTtl+YtMicJ5f8ZDf7FvxB0djpO/+X/GpYPTOfnJMll+s8V16x+TGwxnqklb HkYWuN2/68j9BngbQPsrFlkIaKUIl2uasu+5frcFiiJuZyQvE2tu3CslqDM5Pby13aFtKm mDhx1R4auwH5w5w+DMwFiESaOlSHRxc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-67-ioilyjDyOoyG3YriGikekw-1; Thu, 09 Sep 2021 12:23:49 -0400 X-MC-Unique: ioilyjDyOoyG3YriGikekw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 999D01006AA6; Thu, 9 Sep 2021 16:22:56 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.192.233]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8560777718; Thu, 9 Sep 2021 16:22:53 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-s390@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, David Hildenbrand , Christian Borntraeger , Janosch Frank , Cornelia Huck , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Niklas Schnelle , Gerald Schaefer , Ulrich Weigand Subject: [PATCH resend RFC 1/9] s390/gmap: validate VMA in __gmap_zap() Date: Thu, 9 Sep 2021 18:22:40 +0200 Message-Id: <20210909162248.14969-2-david@redhat.com> In-Reply-To: <20210909162248.14969-1-david@redhat.com> References: <20210909162248.14969-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=awbT2nxU; spf=none (imf26.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 216.205.24.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 2326720019DE X-Stat-Signature: ym6k4xs4z9e97zsd3n8rkkcz4ksyss39 X-HE-Tag: 1631204630-723047 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: 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"). The pure prescence in our guest_to_host radix tree does not imply that there is a VMA. Further, we should not allocate page tables (via get_locked_pte()) 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(). Note that gmap_discard() is different: zap_page_range()->unmap_single_vma() makes sure to stay within VMA boundaries. Fixes: b31288fa83b2 ("s390/kvm: support collaborative memory management") Signed-off-by: David Hildenbrand Reviewed-by: Claudio Imbrenda --- arch/s390/mm/gmap.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 9bb2c7512cd5..b6b56cd4ca64 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -673,6 +673,7 @@ EXPORT_SYMBOL_GPL(gmap_fault); */ void __gmap_zap(struct gmap *gmap, unsigned long gaddr) { + struct vm_area_struct *vma; unsigned long vmaddr; spinlock_t *ptl; pte_t *ptep; @@ -682,6 +683,11 @@ void __gmap_zap(struct gmap *gmap, unsigned long gaddr) gaddr >> PMD_SHIFT); if (vmaddr) { vmaddr |= gaddr & ~PMD_MASK; + + vma = vma_lookup(gmap->mm, vmaddr); + if (!vma || is_vm_hugetlb_page(vma)) + return; + /* Get pointer to the page table entry */ ptep = get_locked_pte(gmap->mm, vmaddr, &ptl); if (likely(ptep))