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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 56038C4360C for ; Thu, 10 Oct 2019 16:15:19 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 280FF208C3 for ; Thu, 10 Oct 2019 16:15:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 280FF208C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:41888 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIb5x-0001yE-T4 for qemu-devel@archiver.kernel.org; Thu, 10 Oct 2019 12:15:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38511) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIaoS-0003qA-9u for qemu-devel@nongnu.org; Thu, 10 Oct 2019 11:57:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iIaoP-000278-Sp for qemu-devel@nongnu.org; Thu, 10 Oct 2019 11:57:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57476) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iIaoG-00024p-Q0; Thu, 10 Oct 2019 11:57:02 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 7FA3A10CBC4B; Thu, 10 Oct 2019 15:56:58 +0000 (UTC) Received: from [10.3.116.168] (ovpn-116-168.phx2.redhat.com [10.3.116.168]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 28886600C4; Thu, 10 Oct 2019 15:56:58 +0000 (UTC) Subject: Re: [PATCH 1/2] qcow2: Limit total allocation range to INT_MAX To: Max Reitz , qemu-block@nongnu.org References: <20191010100858.1261-1-mreitz@redhat.com> <20191010100858.1261-2-mreitz@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <0e08004e-3e96-8b6d-82b6-d7bbbcbea807@redhat.com> Date: Thu, 10 Oct 2019 10:56:57 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.0 MIME-Version: 1.0 In-Reply-To: <20191010100858.1261-2-mreitz@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.66]); Thu, 10 Oct 2019 15:56:58 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 10/10/19 5:08 AM, Max Reitz wrote: > When the COW areas are included, the size of an allocation can exceed > INT_MAX. This is kind of limited by handle_alloc() in that it already > caps avail_bytes at INT_MAX, but the number of clusters still reflects > the original length. > > This can have all sorts of effects, ranging from the storage layer write > call failing to image corruption. (If there were no image corruption, > then I suppose there would be data loss because the .cow_end area is > forced to be empty, even though there might be something we need to > COW.) > > Fix all of it by limiting nb_clusters so the equivalent number of bytes > will not exceed INT_MAX. > > Cc: qemu-stable@nongnu.org > Signed-off-by: Max Reitz > --- > block/qcow2-cluster.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org