xemu/tests/qemu-iotests/085
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
#
# Live snapshot tests
#
# This tests live snapshots of images on a running QEMU instance, using
# QMP commands. Both single disk snapshots, and transactional group
# snapshots are performed.
#
# Copyright (C) 2014 Red Hat, Inc.
# Copyright (C) 2015 Igalia, S.L.
#
# 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=jcody@redhat.com
seq=`basename $0`
echo "QA output created by $seq"
status=1 # failure is the default!
snapshot_virt0="snapshot-v0.qcow2"
snapshot_virt1="snapshot-v1.qcow2"
SNAPSHOTS=10
_cleanup()
{
_cleanup_qemu
_cleanup_test_img
for i in $(seq 1 ${SNAPSHOTS})
do
_rm_test_img "${TEST_DIR}/${i}-${snapshot_virt0}"
_rm_test_img "${TEST_DIR}/${i}-${snapshot_virt1}"
done
for img in "${TEST_IMG}".{1,2,base}
do
_rm_test_img "$img"
done
}
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
# ${1}: unique identifier for the snapshot filename
create_single_snapshot()
{
cmd="{ 'execute': 'blockdev-snapshot-sync',
'arguments': { 'device': 'virtio0',
'snapshot-file':'${TEST_DIR}/${1}-${snapshot_virt0}',
'format': 'qcow2' } }"
_send_qemu_cmd $h "${cmd}" "return"
}
# ${1}: unique identifier for the snapshot filename
create_group_snapshot()
{
cmd="{ 'execute': 'transaction', 'arguments':
{'actions': [
{ 'type': 'blockdev-snapshot-sync', 'data' :
{ 'device': 'virtio0',
'snapshot-file': '${TEST_DIR}/${1}-${snapshot_virt0}' } },
{ 'type': 'blockdev-snapshot-sync', 'data' :
{ 'device': 'virtio1',
'snapshot-file': '${TEST_DIR}/${1}-${snapshot_virt1}' } } ]
} }"
_send_qemu_cmd $h "${cmd}" "return"
}
# ${1}: unique identifier for the snapshot filename
# ${2}: extra_params to the blockdev-add command
# ${3}: filename
do_blockdev_add()
{
cmd="{ 'execute': 'blockdev-add', 'arguments':
{ 'driver': 'qcow2', 'node-name': 'snap_${1}', ${2}
'file':
{ 'driver': 'file', 'filename': '${3}',
'node-name': 'file_${1}' } } }"
_send_qemu_cmd $h "${cmd}" "return"
}
# ${1}: unique identifier for the snapshot filename
add_snapshot_image()
{
base_image="${TEST_DIR}/$((${1}-1))-${snapshot_virt0}"
snapshot_file="${TEST_DIR}/${1}-${snapshot_virt0}"
TEST_IMG=$snapshot_file _make_test_img -u -b "${base_image}" -F $IMGFMT "$size"
do_blockdev_add "$1" "'backing': null, " "${snapshot_file}"
}
# ${1}: unique identifier for the snapshot filename
# ${2}: expected response, defaults to 'return'
blockdev_snapshot()
{
cmd="{ 'execute': 'blockdev-snapshot',
'arguments': { 'node': 'virtio0',
'overlay':'snap_${1}' } }"
_send_qemu_cmd $h "${cmd}" "${2:-return}"
}
size=128M
TEST_IMG="$TEST_IMG.1" _make_test_img $size
TEST_IMG="$TEST_IMG.2" _make_test_img $size
echo
echo === Running QEMU ===
echo
qemu_comm_method="qmp"
_launch_qemu -drive file="${TEST_IMG}.1",if=virtio -drive file="${TEST_IMG}.2",if=virtio
h=$QEMU_HANDLE
echo
echo === Sending capabilities ===
echo
_send_qemu_cmd $h "{ 'execute': 'qmp_capabilities' }" "return"
# Tests for the blockdev-snapshot-sync command
echo
echo === Create a single snapshot on virtio0 ===
echo
create_single_snapshot 1
echo
echo === Invalid command - missing device and nodename ===
echo
_send_qemu_cmd $h "{ 'execute': 'blockdev-snapshot-sync',
'arguments': { 'snapshot-file':'${TEST_DIR}/1-${snapshot_virt0}',
'format': 'qcow2' } }" "error"
echo
echo === Invalid command - missing snapshot-file ===
echo
_send_qemu_cmd $h "{ 'execute': 'blockdev-snapshot-sync',
'arguments': { 'device': 'virtio0',
'format': 'qcow2' } }" "error"
echo
echo
echo === Create several transactional group snapshots ===
echo
for i in $(seq 2 ${SNAPSHOTS})
do
create_group_snapshot ${i}
done
# Tests for the blockdev-snapshot command
echo
echo === Create a couple of snapshots using blockdev-snapshot ===
echo
SNAPSHOTS=$((${SNAPSHOTS}+1))
add_snapshot_image ${SNAPSHOTS}
blockdev_snapshot ${SNAPSHOTS}
SNAPSHOTS=$((${SNAPSHOTS}+1))
add_snapshot_image ${SNAPSHOTS}
blockdev_snapshot ${SNAPSHOTS}
echo
echo === Invalid command - cannot create a snapshot using a file BDS ===
echo
_send_qemu_cmd $h "{ 'execute': 'blockdev-snapshot',
'arguments': { 'node':'virtio0',
'overlay':'file_${SNAPSHOTS}' }
}" "error"
echo
echo === Invalid command - snapshot node used as active layer ===
echo
blockdev_snapshot ${SNAPSHOTS} error
_send_qemu_cmd $h "{ 'execute': 'blockdev-snapshot',
'arguments': { 'node':'virtio0',
'overlay':'virtio0' }
}" "error"
_send_qemu_cmd $h "{ 'execute': 'blockdev-snapshot',
'arguments': { 'node':'virtio0',
'overlay':'virtio1' }
}" "error"
echo
echo === Invalid command - snapshot node used as backing hd ===
echo
blockdev_snapshot $((${SNAPSHOTS}-1)) error
echo
echo === Invalid command - snapshot node has a backing image ===
echo
SNAPSHOTS=$((${SNAPSHOTS}+1))
TEST_IMG="$TEST_IMG.base" _make_test_img "$size"
_make_test_img -b "${TEST_IMG}.base" -F $IMGFMT "$size"
do_blockdev_add ${SNAPSHOTS} "" "${TEST_IMG}"
blockdev_snapshot ${SNAPSHOTS} error
echo
echo === Invalid command - The node does not exist ===
echo
blockdev_snapshot $((${SNAPSHOTS}+1)) error
_send_qemu_cmd $h "{ 'execute': 'blockdev-snapshot',
'arguments': { 'node':'nodevice',
'overlay':'snap_${SNAPSHOTS}' }
}" "error"
# success, all done
echo "*** done"
rm -f $seq.full
status=0