xemu/tests/qemu-iotests/191
Eric Blake b66ff2c298 iotests: Specify explicit backing format where sensible
There are many existing qcow2 images that specify a backing file but
no format.  This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev.  With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently).  But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.

The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past.  It's time to set a better example in our own
iotests of properly setting this parameter.

iotest calls to create, rebase, and convert are all impacted to some
degree.  It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F.  (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-14 15:18:59 +02:00

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#!/usr/bin/env bash
#
# Test commit block job where top has two parents
#
# Copyright (C) 2017 Red Hat, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# creator
owner=kwolf@redhat.com
seq=`basename $0`
echo "QA output created by $seq"
status=1 # failure is the default!
_cleanup()
{
_rm_test_img "${TEST_IMG}.mid"
_rm_test_img "${TEST_IMG}.ovl2"
_rm_test_img "${TEST_IMG}.ovl3"
_cleanup_test_img
_cleanup_qemu
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common.rc
. ./common.filter
. ./common.qemu
_supported_fmt qcow2
_supported_proto file
# An external data file would change the query-named-block-nodes output
_unsupported_imgopts data_file
size=64M
echo
echo === Preparing and starting VM ===
echo
TEST_IMG="${TEST_IMG}.base" _make_test_img $size
TEST_IMG="${TEST_IMG}.mid" _make_test_img -o "backing_fmt=$IMGFMT" -b "${TEST_IMG}.base"
_make_test_img -b "${TEST_IMG}.mid" -F $IMGFMT
TEST_IMG="${TEST_IMG}.ovl2" _make_test_img -b "${TEST_IMG}.mid" -F $IMGFMT
$QEMU_IO -c 'write -P 0x55 1M 64k' "${TEST_IMG}.mid" | _filter_qemu_io
qemu_comm_method="qmp"
qmp_pretty="y"
_launch_qemu \
-blockdev "driver=${IMGFMT},file.driver=file,file.filename=${TEST_IMG}.base,node-name=base" \
-blockdev "driver=${IMGFMT},file.driver=file,file.filename=${TEST_IMG}.mid,node-name=mid,backing=base" \
-blockdev "driver=${IMGFMT},file.driver=file,file.filename=${TEST_IMG},node-name=top,backing=mid" \
-blockdev "driver=${IMGFMT},file.driver=file,file.filename=${TEST_IMG}.ovl2,node-name=top2,backing=mid"
h=$QEMU_HANDLE
_send_qemu_cmd $h "{ 'execute': 'qmp_capabilities' }" '^}'
echo
echo === Perform commit job ===
echo
_send_qemu_cmd $h \
"{ 'execute': 'block-commit',
'arguments': { 'job-id': 'commit0',
'device': 'top',
'base':'$TEST_IMG.base',
'top': '$TEST_IMG.mid' } }" \
'"status": "null"'
_send_qemu_cmd $h "" "^}"
echo
echo === Check that both top and top2 point to base now ===
echo
_send_qemu_cmd $h "{ 'execute': 'query-named-block-nodes' }" "^}" |
_filter_generated_node_ids | _filter_actual_image_size | _filter_img_info
_send_qemu_cmd $h "{ 'execute': 'quit' }" "^}"
wait=1 _cleanup_qemu
_img_info
TEST_IMG="$TEST_IMG.ovl2" _img_info
echo
echo === Preparing and starting VM with -drive ===
echo
TEST_IMG="${TEST_IMG}.base" _make_test_img $size
TEST_IMG="${TEST_IMG}.mid" _make_test_img -b "${TEST_IMG}.base" -F $IMGFMT
_make_test_img -b "${TEST_IMG}.mid" -F $IMGFMT
TEST_IMG="${TEST_IMG}.ovl2" _make_test_img -b "${TEST_IMG}.mid" -F $IMGFMT
TEST_IMG="${TEST_IMG}.ovl3" _make_test_img -b "${TEST_IMG}.ovl2" -F $IMGFMT
$QEMU_IO -c 'write -P 0x55 1M 64k' "${TEST_IMG}.mid" | _filter_qemu_io
qemu_comm_method="qmp"
qmp_pretty="y"
_launch_qemu \
-drive "driver=${IMGFMT},file=${TEST_IMG},node-name=top,backing.node-name=mid" \
-drive "driver=${IMGFMT},file=${TEST_IMG}.ovl3,node-name=top2,backing.backing=mid"
h=$QEMU_HANDLE
_send_qemu_cmd $h "{ 'execute': 'qmp_capabilities' }" '^}'
echo
echo === Perform commit job ===
echo
_send_qemu_cmd $h \
"{ 'execute': 'block-commit',
'arguments': { 'job-id': 'commit0',
'device': 'top',
'base':'$TEST_IMG.base',
'top': '$TEST_IMG.mid' } }" \
'"status": "null"'
_send_qemu_cmd $h "" "^}"
echo
echo === Check that both top and top2 point to base now ===
echo
_send_qemu_cmd $h "{ 'execute': 'query-named-block-nodes' }" "^}" |
_filter_generated_node_ids | _filter_actual_image_size | _filter_img_info
_send_qemu_cmd $h "{ 'execute': 'quit' }" "^}"
wait=1 _cleanup_qemu
_img_info
TEST_IMG="$TEST_IMG.ovl2" _img_info
# success, all done
echo "*** done"
rm -f $seq.full
status=0