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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 8A219C3A5A0 for ; Mon, 19 Aug 2019 19:35:46 +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 6059E206C1 for ; Mon, 19 Aug 2019 19:35:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6059E206C1 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]:56950 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hznRR-0000QU-IA for qemu-devel@archiver.kernel.org; Mon, 19 Aug 2019 15:35:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38122) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hznQh-0008Gb-KL for qemu-devel@nongnu.org; Mon, 19 Aug 2019 15:35:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hznQg-0006C3-Kx for qemu-devel@nongnu.org; Mon, 19 Aug 2019 15:34:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39216) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hznQe-0006BA-8l; Mon, 19 Aug 2019 15:34:56 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 93C9DA38181; Mon, 19 Aug 2019 19:34:55 +0000 (UTC) Received: from [10.3.117.3] (ovpn-117-3.phx2.redhat.com [10.3.117.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2AA5450; Mon, 19 Aug 2019 19:34:55 +0000 (UTC) To: Max Reitz , qemu-block@nongnu.org References: <20190819185602.4267-1-mreitz@redhat.com> <20190819185602.4267-5-mreitz@redhat.com> From: Eric Blake Openpgp: preference=signencrypt Autocrypt: addr=eblake@redhat.com; keydata= xsBNBEvHyWwBCACw7DwsQIh0kAbUXyqhfiKAKOTVu6OiMGffw2w90Ggrp4bdVKmCaEXlrVLU xphBM8mb+wsFkU+pq9YR621WXo9REYVIl0FxKeQo9dyQBZ/XvmUMka4NOmHtFg74nvkpJFCD TUNzmqfcjdKhfFV0d7P/ixKQeZr2WP1xMcjmAQY5YvQ2lUoHP43m8TtpB1LkjyYBCodd+LkV GmCx2Bop1LSblbvbrOm2bKpZdBPjncRNob73eTpIXEutvEaHH72LzpzksfcKM+M18cyRH+nP sAd98xIbVjm3Jm4k4d5oQyE2HwOur+trk2EcxTgdp17QapuWPwMfhaNq3runaX7x34zhABEB AAHNHkVyaWMgQmxha2UgPGVibGFrZUByZWRoYXQuY29tPsLAegQTAQgAJAIbAwULCQgHAwUV CgkICwUWAgMBAAIeAQIXgAUCS8fL9QIZAQAKCRCnoWtKJSdDahBHCACbl/5FGkUqJ89GAjeX RjpAeJtdKhujir0iS4CMSIng7fCiGZ0fNJCpL5RpViSo03Q7l37ss+No+dJI8KtAp6ID+PMz wTJe5Egtv/KGUKSDvOLYJ9WIIbftEObekP+GBpWP2+KbpADsc7EsNd70sYxExD3liwVJYqLc Rw7so1PEIFp+Ni9A1DrBR5NaJBnno2PHzHPTS9nmZVYm/4I32qkLXOcdX0XElO8VPDoVobG6 gELf4v/vIImdmxLh/w5WctUpBhWWIfQDvSOW2VZDOihm7pzhQodr3QP/GDLfpK6wI7exeu3P pfPtqwa06s1pae3ad13mZGzkBdNKs1HEm8x6zsBNBEvHyWwBCADGkMFzFjmmyqAEn5D+Mt4P zPdO8NatsDw8Qit3Rmzu+kUygxyYbz52ZO40WUu7EgQ5kDTOeRPnTOd7awWDQcl1gGBXgrkR pAlQ0l0ReO57Q0eglFydLMi5bkwYhfY+TwDPMh3aOP5qBXkm4qIYSsxb8A+i00P72AqFb9Q7 3weG/flxSPApLYQE5qWGSXjOkXJv42NGS6o6gd4RmD6Ap5e8ACo1lSMPfTpGzXlt4aRkBfvb NCfNsQikLZzFYDLbQgKBA33BDeV6vNJ9Cj0SgEGOkYyed4I6AbU0kIy1hHAm1r6+sAnEdIKj cHi3xWH/UPrZW5flM8Kqo14OTDkI9EtlABEBAAHCwF8EGAEIAAkFAkvHyWwCGwwACgkQp6Fr SiUnQ2q03wgAmRFGDeXzc58NX0NrDijUu0zx3Lns/qZ9VrkSWbNZBFjpWKaeL1fdVeE4TDGm I5mRRIsStjQzc2R9b+2VBUhlAqY1nAiBDv0Qnt+9cLiuEICeUwlyl42YdwpmY0ELcy5+u6wz mK/jxrYOpzXKDwLq5k4X+hmGuSNWWAN3gHiJqmJZPkhFPUIozZUCeEc76pS/IUN72NfprZmF Dp6/QDjDFtfS39bHSWXKVZUbqaMPqlj/z6Ugk027/3GUjHHr8WkeL1ezWepYDY7WSoXwfoAL 2UXYsMAr/uUncSKlfjvArhsej0S4zbqim2ZY6S8aRWw94J3bSvJR+Nwbs34GPTD4Pg== Organization: Red Hat, Inc. Message-ID: <85d04ded-0bf6-ab67-7af9-cc97f30ad366@redhat.com> Date: Mon, 19 Aug 2019 14:34:54 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190819185602.4267-5-mreitz@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="yIatP1svSXok5JHcyK2vcrHVjrRNbqgnX" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.68]); Mon, 19 Aug 2019 19:34:55 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v2 04/16] qcow2: Keep unknown extra snapshot data 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" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --yIatP1svSXok5JHcyK2vcrHVjrRNbqgnX Content-Type: multipart/mixed; boundary="SE5eowyH54Z7ATU3w2ugNsdyWe8HXzaTi"; protected-headers="v1" From: Eric Blake To: Max Reitz , qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Kevin Wolf Message-ID: <85d04ded-0bf6-ab67-7af9-cc97f30ad366@redhat.com> Subject: Re: [PATCH v2 04/16] qcow2: Keep unknown extra snapshot data References: <20190819185602.4267-1-mreitz@redhat.com> <20190819185602.4267-5-mreitz@redhat.com> In-Reply-To: <20190819185602.4267-5-mreitz@redhat.com> --SE5eowyH54Z7ATU3w2ugNsdyWe8HXzaTi Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 8/19/19 1:55 PM, Max Reitz wrote: > The qcow2 specification says to ignore unknown extra data fields in > snapshot table entries. Currently, we discard it whenever we update th= e > image, which is a bit different from "ignore". >=20 > This patch makes the qcow2 driver keep all unknown extra data fields > when updating an image's snapshot table. >=20 > @@ -80,31 +80,53 @@ int qcow2_read_snapshots(BlockDriverState *bs, Erro= r **errp) > sn->date_sec =3D be32_to_cpu(h.date_sec); > sn->date_nsec =3D be32_to_cpu(h.date_nsec); > sn->vm_clock_nsec =3D be64_to_cpu(h.vm_clock_nsec); > - extra_data_size =3D be32_to_cpu(h.extra_data_size); > + sn->extra_data_size =3D be32_to_cpu(h.extra_data_size); > =20 > id_str_size =3D be16_to_cpu(h.id_str_size); > name_size =3D be16_to_cpu(h.name_size); > =20 > - /* Read extra data */ > + if (sn->extra_data_size > QCOW_MAX_SNAPSHOT_EXTRA_DATA) { > + ret =3D -EFBIG; > + error_setg(errp, "Too much extra metadata in snapshot tabl= e " > + "entry %i", i); > + goto fail; We fail if extra_data_size is > 1024... > + if (sn->extra_data_size > sizeof(extra)) { > + /* Store unknown extra data */ > + size_t unknown_extra_data_size =3D > + sn->extra_data_size - sizeof(extra); > + But read at most 1008 bytes into sn->unknown_extra_data. > @@ -234,6 +257,22 @@ static int qcow2_write_snapshots(BlockDriverState = *bs) > } > offset +=3D sizeof(extra); > =20 > + if (sn->extra_data_size > sizeof(extra)) { > + size_t unknown_extra_data_size =3D > + sn->extra_data_size - sizeof(extra); > + > + /* qcow2_read_snapshots() ensures no unbounded allocation = */ > + assert(unknown_extra_data_size <=3D BDRV_REQUEST_MAX_BYTES= ); So this assertion is quite loose in what it permits; tighter would be assert(unknown_extra_data_size <=3D QCOW_MAX_SNAPSHOT_EXTRA_DATA - sizeof(extra)) --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org --SE5eowyH54Z7ATU3w2ugNsdyWe8HXzaTi-- --yIatP1svSXok5JHcyK2vcrHVjrRNbqgnX Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAl1a+d4ACgkQp6FrSiUn Q2rqlggArKP87NFD3iaj1hPLzlZbdOLox2KuGHzBazi5Lmk2EtnyCYFdvfm02Dw+ TsUWwr5K4JH9BRBfMPMxCE1++dLNlnT30z2t6e4aBepQW9z4kJoOkWgY5QZrnXst D6L/5mqT8alSl+jiu13nXwaz86O/nkbYZIkCFXoc4peMnC9vad2w9QMKZaph7Ncv 51mHbonLwInSai4bHg+hsyTnJ6rrJtHfKbVDkyoHBROLl3ge15SpvX09Y/TuZtqM 5hD1ioXxL0EgwoLzqRch0O2UxeLo47Ol6BCcUisJ7BbUIuOxeWCnUqz+2mPuEDiO w9BwhzDsTDac+4bS3T7wjPmbFhM8nQ== =WlJ4 -----END PGP SIGNATURE----- --yIatP1svSXok5JHcyK2vcrHVjrRNbqgnX--