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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 00A35C32751 for ; Wed, 31 Jul 2019 09:07:29 +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 CAF6D2067D for ; Wed, 31 Jul 2019 09:07:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CAF6D2067D 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]:39152 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hska0-0004Oj-2D for qemu-devel@archiver.kernel.org; Wed, 31 Jul 2019 05:07:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55756) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hskZY-0003vk-5J for qemu-devel@nongnu.org; Wed, 31 Jul 2019 05:07:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hskZX-0001Vz-5a for qemu-devel@nongnu.org; Wed, 31 Jul 2019 05:07:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57218) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hskZU-0001VC-RK; Wed, 31 Jul 2019 05:06:57 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 362BB81F18; Wed, 31 Jul 2019 09:06:56 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-117-44.ams2.redhat.com [10.36.117.44]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C004E1000329; Wed, 31 Jul 2019 09:06:54 +0000 (UTC) To: Eric Blake , qemu-block@nongnu.org References: <20190730172508.19911-1-mreitz@redhat.com> <20190730172508.19911-9-mreitz@redhat.com> From: Max Reitz Openpgp: preference=signencrypt Autocrypt: addr=mreitz@redhat.com; prefer-encrypt=mutual; keydata= mQENBFXOJlcBCADEyyhOTsoa/2ujoTRAJj4MKA21dkxxELVj3cuILpLTmtachWj7QW+TVG8U /PsMCFbpwsQR7oEy8eHHZwuGQsNpEtNC2G/L8Yka0BIBzv7dEgrPzIu+W3anZXQW4702+uES U29G8TP/NGfXRRHGlbBIH9KNUnOSUD2vRtpOLXkWsV5CN6vQFYgQfFvmp5ZpPeUe6xNplu8V mcTw8OSEDW/ZnxJc8TekCKZSpdzYoxfzjm7xGmZqB18VFwgJZlIibt1HE0EB4w5GsD7x5ekh awIe3RwoZgZDLQMdOitJ1tUc8aqaxvgA4tz6J6st8D8pS//m1gAoYJWGwwIVj1DjTYLtABEB AAG0HU1heCBSZWl0eiA8bXJlaXR6QHJlZGhhdC5jb20+iQFTBBMBCAA9AhsDBQkSzAMABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheABQJVzie5FRhoa3A6Ly9rZXlzLmdudXBnLm5ldAAKCRD0 B9sAYdXPQDcIB/9uNkbYEex1rHKz3mr12uxYMwLOOFY9fstP5aoVJQ1nWQVB6m2cfKGdcRe1 2/nFaHSNAzT0NnKz2MjhZVmcrpyd2Gp2QyISCfb1FbT82GMtXFj1wiHmPb3CixYmWGQUUh+I AvUqsevLA+WihgBUyaJq/vuDVM1/K9Un+w+Tz5vpeMidlIsTYhcsMhn0L9wlCjoucljvbDy/ 8C9L2DUdgi3XTa0ORKeflUhdL4gucWoAMrKX2nmPjBMKLgU7WLBc8AtV+84b9OWFML6NEyo4 4cP7cM/07VlJK53pqNg5cHtnWwjHcbpGkQvx6RUx6F1My3y52vM24rNUA3+ligVEgPYBuQEN BFXOJlcBCADAmcVUNTWT6yLWQHvxZ0o47KCP8OcLqD+67T0RCe6d0LP8GsWtrJdeDIQk+T+F xO7DolQPS6iQ6Ak2/lJaPX8L0BkEAiMuLCKFU6Bn3lFOkrQeKp3u05wCSV1iKnhg0UPji9V2 W5eNfy8F4ZQHpeGUGy+liGXlxqkeRVhLyevUqfU0WgNqAJpfhHSGpBgihUupmyUg7lfUPeRM DzAN1pIqoFuxnN+BRHdAecpsLcbR8sQddXmDg9BpSKozO/JyBmaS1RlquI8HERQoe6EynJhd 64aICHDfj61rp+/0jTIcevxIIAzW70IadoS/y3DVIkuhncgDBvGbF3aBtjrJVP+5ABEBAAGJ ASUEGAEIAA8FAlXOJlcCGwwFCRLMAwAACgkQ9AfbAGHVz0CbFwf9F/PXxQR9i4N0iipISYjU sxVdjJOM2TMut+ZZcQ6NSMvhZ0ogQxJ+iEQ5OjnIputKvPVd5U7WRh+4lF1lB/NQGrGZQ1ic alkj6ocscQyFwfib+xIe9w8TG1CVGkII7+TbS5pXHRxZH1niaRpoi/hYtgzkuOPp35jJyqT/ /ELbqQTDAWcqtJhzxKLE/ugcOMK520dJDeb6x2xVES+S5LXby0D4juZlvUj+1fwZu+7Io5+B bkhSVPb/QdOVTpnz7zWNyNw+OONo1aBUKkhq2UIByYXgORPFnbfMY7QWHcjpBVw9MgC4tGeF R4bv+1nAMMxKmb5VvQCExr0eFhJUAHAhVg== Message-ID: Date: Wed, 31 Jul 2019 11:06:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="WNCqFY6v4v0mDJWuI3vyw0cC8EoZ0v8Ml" X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 31 Jul 2019 09:06:56 +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 for-4.2 08/13] qcow2: Fix broken snapshot table entries 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) --WNCqFY6v4v0mDJWuI3vyw0cC8EoZ0v8Ml Content-Type: multipart/mixed; boundary="aQUIwxmaRjpto4Zd44frl2RQXrKVxAvio"; protected-headers="v1" From: Max Reitz To: Eric Blake , qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Kevin Wolf Message-ID: Subject: Re: [PATCH for-4.2 08/13] qcow2: Fix broken snapshot table entries References: <20190730172508.19911-1-mreitz@redhat.com> <20190730172508.19911-9-mreitz@redhat.com> In-Reply-To: --aQUIwxmaRjpto4Zd44frl2RQXrKVxAvio Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 30.07.19 21:02, Eric Blake wrote: > On 7/30/19 12:25 PM, Max Reitz wrote: >> The only case where we currently reject snapshot table entries is when= >> they have too much extra data. Fix them with qemu-img check -r all by= >> counting it as a corruption, reducing their extra_data_size, and then >> letting qcow2_check_fix_snapshot_table() do the rest. >> >> Signed-off-by: Max Reitz >> --- >> block/qcow2-snapshot.c | 69 ++++++++++++++++++++++++++++++++++-------= - >> 1 file changed, 56 insertions(+), 13 deletions(-) >> >=20 >> @@ -112,16 +141,22 @@ int qcow2_read_snapshots(BlockDriverState *bs, E= rror **errp) >> } >> =20 >> if (sn->extra_data_size > sizeof(extra)) { >> - /* Store unknown extra data */ >> size_t unknown_extra_data_size =3D >> sn->extra_data_size - sizeof(extra); >> =20 >> - sn->unknown_extra_data =3D g_malloc(unknown_extra_data_si= ze); >> - ret =3D bdrv_pread(bs->file, offset, sn->unknown_extra_da= ta, >> - unknown_extra_data_size); >> - if (ret < 0) { >> - error_setg_errno(errp, -ret, "Failed to read snapshot= table"); >> - goto fail; >> + if (discard_unknown_extra_data) { >> + /* Discard unknown extra data */ >> + sn->extra_data_size =3D sizeof(extra); >=20 > This truncates it down to just the data we know. Should it instead > truncate down to the 1024 bytes of QCOW_MAX_SNAPSHOT_EXTRA_DATA defined= > in 2/13? (We can't keep all of the user's extra stuff, but we can at > least try to preserve as much as possible) On one hand, potentially cutting unknown data in half sounds like not such a good idea to me. On the other, a field can only be considered present if it is fully present. So cutting any optional data in half shouldn=E2=80=99t have any= negative impact. So, yes, truncating it down to 1024 bytes sounds good. Max > Otherwise, looks good. > Reviewed-by: Eric Blake >=20 --aQUIwxmaRjpto4Zd44frl2RQXrKVxAvio-- --WNCqFY6v4v0mDJWuI3vyw0cC8EoZ0v8Ml Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl1BWiwACgkQ9AfbAGHV z0CiTggAqmGIYRJ/LX9BbE2vanEyUH4aJizCDAhGFI6sj/LOJomF0o1ARS/MY2eu 9yKSUJzIhCeZikZJsg/Pflc5DxAjPhzxjU469uaW8Jw5TufJIxULfRtKUAZcFFHp RaLLbiV40U+IQtyJvchFz0FdIzC5wBoPcxpXFRJQdJFlh1bth0S7+18oF/76bdNv HzBV34/kugK66DQt95BWkgQTKqAyR52kXNi8Xc6VZ9BWkrNjMqmRTDvV7Jvublqu MUOg4+H/XL1rtuCeaVKF7z5sXfWfjGNHAmPqmwmOjAn8p2D14WIZ4AN2L4rFgafy tENEQQigigCa7oEQPwjVPKCwc0xV3A== =f2cU -----END PGP SIGNATURE----- --WNCqFY6v4v0mDJWuI3vyw0cC8EoZ0v8Ml--