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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 7D82EC3A59E for ; Mon, 2 Sep 2019 13:47:52 +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 4DA66216C8 for ; Mon, 2 Sep 2019 13:47:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4DA66216C8 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]:36754 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i4mgR-0006fw-DN for qemu-devel@archiver.kernel.org; Mon, 02 Sep 2019 09:47:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53949) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i4mf9-00060i-TX for qemu-devel@nongnu.org; Mon, 02 Sep 2019 09:46:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i4mf8-0007ar-Ph for qemu-devel@nongnu.org; Mon, 02 Sep 2019 09:46:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41672) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i4mf4-0007Uz-U1; Mon, 02 Sep 2019 09:46:27 -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 40DE73082E10; Mon, 2 Sep 2019 13:46:25 +0000 (UTC) Received: from localhost.localdomain (ovpn-116-189.ams2.redhat.com [10.36.116.189]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D738460920; Mon, 2 Sep 2019 13:46:23 +0000 (UTC) Date: Mon, 2 Sep 2019 15:46:22 +0200 From: Kevin Wolf To: Peter Lieven Message-ID: <20190902134622.GH13140@localhost.localdomain> References: <20190829133615.29873-1-pl@kamp.de> <20190902130701.GE13140@localhost.localdomain> <7992af97-086e-b1c1-2b1a-fa72727e04c1@kamp.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <7992af97-086e-b1c1-2b1a-fa72727e04c1@kamp.de> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Mon, 02 Sep 2019 13:46:25 +0000 (UTC) Content-Transfer-Encoding: quoted-printable 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] block/vhdx: add check for truncated image files 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: codyprime@gmail.com, Jan-Hendrik Frintrop , qemu-devel@nongnu.org, qemu-block@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 02.09.2019 um 15:15 hat Peter Lieven geschrieben: > Am 02.09.19 um 15:07 schrieb Kevin Wolf: > > Am 29.08.2019 um 15:36 hat Peter Lieven geschrieben: > > > qemu is currently not able to detect truncated vhdx image files. > > > Add a basic check if all allocated blocks are reachable to vhdx_co_= check. > > >=20 > > > Signed-off-by: Jan-Hendrik Frintrop > > > Signed-off-by: Peter Lieven > > > --- > > > block/vhdx.c | 19 +++++++++++++++++++ > > > 1 file changed, 19 insertions(+) > > >=20 > > > diff --git a/block/vhdx.c b/block/vhdx.c > > > index 6a09d0a55c..4382b1375d 100644 > > > --- a/block/vhdx.c > > > +++ b/block/vhdx.c > > > @@ -2068,10 +2068,29 @@ static int coroutine_fn vhdx_co_check(Block= DriverState *bs, > > > BdrvCheckMode fix) > > > { > > > BDRVVHDXState *s =3D bs->opaque; > > > + VHDXSectorInfo sinfo; > > > + int64_t file_size =3D bdrv_get_allocated_file_size(bs); > > Don't you mean bdrv_getlength()? > >=20 > > bdrv_get_allocated_file_size() is only the allocated size, i.e. witho= ut > > holes. So a higher offset may actually be present. >=20 >=20 > Isn't bdrv_getlength the virtual disk size? I need to check if a block > points to a location after EOF of the underlying physical file. Yes, it would have to be bdrv_getlength(bs->file->bs), i.e. call it on the protocol layer, not on the format layer. > > > + int64_t sector_num; > > > if (s->log_replayed_on_open) { > > > result->corruptions_fixed++; > > > } > > > + > > > + for (sector_num =3D 0; sector_num < bs->total_sectors; > > > + sector_num +=3D s->block_size / BDRV_SECTOR_SIZE) { > > > + int nb_sectors =3D MIN(bs->total_sectors - sector_num, > > > + s->block_size / BDRV_SECTOR_SIZE); > > > + vhdx_block_translate(s, sector_num, nb_sectors, &sinfo); > > > + if ((s->bat[sinfo.bat_idx] & VHDX_BAT_STATE_BIT_MASK) =3D=3D > > > + PAYLOAD_BLOCK_FULLY_PRESENT) { > > > + if (sinfo.file_offset + > > > + sinfo.sectors_avail * BDRV_SECTOR_SIZE > file_size= ) { > > Do we need to protect against integer overflows here? I think > > sinfo.file_offset comes directly from the image file and might be > > corrupted. > >=20 > > Or has it already been check somewhere? >=20 >=20 > The headers are being checked in vhdx_open.=A0 sinfo.file_offset + > sinfo.sectors_avail * BDRV_SECTOR_SIZE is exactly what is being passed > to bdrv_pread when reading from the image file. Fair enough, though if I'm not missing anything, we only check that BAT entries don't overlap with other regions, not that they aren't too high. And vhdx_block_translate() doesn't seem to check for overflows either before it sets sinfo->sectors_avail. So maybe this is actually a bug that should be fixed in vhdx_block_translate() so that normal accesses get the fix, too. > > > + /* block is past the end of file, image has been t= runcated. */ > > > + result->corruptions++; > > I think we should print an error message like other formats do, so th= at > > the user knows which kind of corruption 'qemu-img check' found (inclu= de > > the guest and host offset of the invalid block). >=20 > What would be the appropriate way to do this? There is no errp in the > check funtion. Inclunde headers so that error_report() is available? Yes, I think error_report() would be fine. qcow2 even just uses fprintf(stderr, ...), but maybe that's something we shouldn't imitate. Kevin