From nobody Mon Feb 9 10:28:31 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1510346164819922.6230041845931; Fri, 10 Nov 2017 12:36:04 -0800 (PST) Received: from localhost ([::1]:43403 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eDG1z-0004n0-WF for importer@patchew.org; Fri, 10 Nov 2017 15:36:04 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54865) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eDFxb-0001E9-Qj for qemu-devel@nongnu.org; Fri, 10 Nov 2017 15:31:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eDFxa-00045O-PJ for qemu-devel@nongnu.org; Fri, 10 Nov 2017 15:31:31 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35772) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eDFxY-00042r-2E; Fri, 10 Nov 2017 15:31:28 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 337995D9EB; Fri, 10 Nov 2017 20:31:27 +0000 (UTC) Received: from localhost (ovpn-204-126.brq.redhat.com [10.40.204.126]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 99B914DA68; Fri, 10 Nov 2017 20:31:23 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Fri, 10 Nov 2017 21:31:08 +0100 Message-Id: <20171110203111.7666-3-mreitz@redhat.com> In-Reply-To: <20171110203111.7666-1-mreitz@redhat.com> References: <20171110203111.7666-1-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Fri, 10 Nov 2017 20:31:27 +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 Subject: [Qemu-devel] [PATCH for-2.11 2/5] qcow2: Unaligned zero cluster in handle_alloc() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , John Snow , Alberto Garcia , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" We should check whether the cluster offset we are about to use is actually valid; that is, whether it is aligned to cluster boundaries. Reported-by: R. Nageswara Sastry Buglink: https://bugs.launchpad.net/qemu/+bug/1728643 Buglink: https://bugs.launchpad.net/qemu/+bug/1728657 Signed-off-by: Max Reitz Reviewed-by: Alberto Garcia Reviewed-by: Eric Blake --- block/qcow2-cluster.c | 13 ++++++++++++- tests/qemu-iotests/060 | 16 ++++++++++++++++ tests/qemu-iotests/060.out | 10 ++++++++++ 3 files changed, 38 insertions(+), 1 deletion(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 2e072ed155..a3fec27bf9 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1308,10 +1308,21 @@ static int handle_alloc(BlockDriverState *bs, uint6= 4_t guest_offset, (!*host_offset || start_of_cluster(s, *host_offset) =3D=3D (entry & L2E_OFFSET_MASK= ))) { + int preallocated_nb_clusters; + + if (offset_into_cluster(s, entry & L2E_OFFSET_MASK)) { + qcow2_signal_corruption(bs, true, -1, -1, "Preallocated zero " + "cluster offset %#llx unaligned (guest= " + "offset: %#" PRIx64 ")", + entry & L2E_OFFSET_MASK, guest_offset); + ret =3D -EIO; + goto fail; + } + /* Try to reuse preallocated zero clusters; contiguous normal clus= ters * would be fine, too, but count_cow_clusters() above has limited * nb_clusters already to a range of COW clusters */ - int preallocated_nb_clusters =3D + preallocated_nb_clusters =3D count_contiguous_clusters(nb_clusters, s->cluster_size, &l2_table[l2_index], QCOW_OFLAG_COPI= ED); assert(preallocated_nb_clusters > 0); diff --git a/tests/qemu-iotests/060 b/tests/qemu-iotests/060 index 56bdf1ee2e..49bc89df38 100755 --- a/tests/qemu-iotests/060 +++ b/tests/qemu-iotests/060 @@ -321,6 +321,22 @@ echo '--- Repairing ---' # because the image was already marked corrupt by that point _check_test_img -r all =20 +echo +echo "=3D=3D=3D Writing to an unaligned preallocated zero cluster =3D=3D= =3D" +echo + +_make_test_img 64M + +# Allocate the L2 table +$QEMU_IO -c "write 0 64k" -c "discard 0 64k" "$TEST_IMG" | _filter_qemu_io +# Pretend there is a preallocated zero cluster somewhere inside the +# image header +poke_file "$TEST_IMG" "$l2_offset" "\x80\x00\x00\x00\x00\x00\x2a\x01" +# Let's write to it! +$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io + +# Can't repair this yet (TODO: We can just deallocate the cluster) + # success, all done echo "*** done" rm -f $seq.full diff --git a/tests/qemu-iotests/060.out b/tests/qemu-iotests/060.out index f013fe73c0..c583076808 100644 --- a/tests/qemu-iotests/060.out +++ b/tests/qemu-iotests/060.out @@ -307,4 +307,14 @@ The following inconsistencies were found and repaired: =20 Double checking the fixed image now... No errors were found on the image. + +=3D=3D=3D Writing to an unaligned preallocated zero cluster =3D=3D=3D + +Formatting 'TEST_DIR/t.IMGFMT', fmt=3DIMGFMT size=3D67108864 +wrote 65536/65536 bytes at offset 0 +64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +discard 65536/65536 bytes at offset 0 +64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +qcow2: Marking image as corrupt: Preallocated zero cluster offset 0x2a00 u= naligned (guest offset: 0); further corruption events will be suppressed +write failed: Input/output error *** done --=20 2.13.6