From patchwork Thu Sep 9 14:59:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 12483357 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 C4989C433EF for ; Thu, 9 Sep 2021 14:59:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5267461167 for ; Thu, 9 Sep 2021 14:59:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5267461167 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 70B346B006C; Thu, 9 Sep 2021 10:59:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6BA96900002; Thu, 9 Sep 2021 10:59:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 55BB66B0073; Thu, 9 Sep 2021 10:59:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0138.hostedemail.com [216.40.44.138]) by kanga.kvack.org (Postfix) with ESMTP id 45A476B006C for ; Thu, 9 Sep 2021 10:59:58 -0400 (EDT) Received: from smtpin40.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id DA5C78249980 for ; Thu, 9 Sep 2021 14:59:57 +0000 (UTC) X-FDA: 78568344834.40.63F309E Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf27.hostedemail.com (Postfix) with ESMTP id 6E2F37000081 for ; Thu, 9 Sep 2021 14:59:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1631199596; 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=JfaPeAiH2lgbLinp4qR5vvan4nts9sfffkBP2qjs7gKsesdijeb0DE1v4lHK+hDPhCr+Ro cPWrMkyh4vIsUcoH5O4Ex67DCgNKukMOwr/3YxLQC6nfarArpzEdUfG1gFoD0BIo/NsKYu a0xK4fxx1dA/psNp7vILSDLZVIqd7Nc= 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-566-qWG1Yqm1OjiYOek_gEs4uw-1; Thu, 09 Sep 2021 10:59:55 -0400 X-MC-Unique: qWG1Yqm1OjiYOek_gEs4uw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A97DC1006AA2; Thu, 9 Sep 2021 14:59:54 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.192.233]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3DF9C53E08; Thu, 9 Sep 2021 14:59:53 +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 Subject: [PATCH RFC 1/9] s390/gmap: validate VMA in __gmap_zap() Date: Thu, 9 Sep 2021 16:59:37 +0200 Message-Id: <20210909145945.12192-2-david@redhat.com> In-Reply-To: <20210909145945.12192-1-david@redhat.com> References: <20210909145945.12192-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Stat-Signature: zo11fwd7myizw8b6m5ibtpjofs49kmmz Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=JfaPeAiH; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf27.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=david@redhat.com X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 6E2F37000081 X-HE-Tag: 1631199597-814654 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 --- 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))