qemu/tests/qemu-iotests/156
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
#
# Tests oVirt-like storage migration:
# - Create snapshot
# - Create target image with (not yet existing) target backing chain
# (i.e. just write the name of a soon-to-be-copied-over backing file into it)
# - drive-mirror the snapshot to the target with mode=existing and sync=top
# - In the meantime, copy the original source files to the destination via
# conventional means (i.e. outside of qemu)
# - Complete the drive-mirror job
# - Delete all source images
#
# Copyright (C) 2016 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=mreitz@redhat.com
seq="$(basename $0)"
echo "QA output created by $seq"
status=1 # failure is the default!
_cleanup()
{
_cleanup_qemu
for img in "$TEST_IMG"{,.target}{,.backing,.overlay}; do
_rm_test_img "$img"
done
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common.rc
. ./common.filter
. ./common.qemu
_supported_fmt qcow2 qed
_supported_proto generic
_unsupported_proto vxhs
# Copying files around with cp does not work with external data files
_unsupported_imgopts data_file
# Create source disk
TEST_IMG="$TEST_IMG.backing" _make_test_img 1M
_make_test_img -b "$TEST_IMG.backing" -F $IMGFMT 1M
$QEMU_IO -c 'write -P 1 0 256k' "$TEST_IMG.backing" | _filter_qemu_io
$QEMU_IO -c 'write -P 2 64k 192k' "$TEST_IMG" | _filter_qemu_io
_launch_qemu -drive if=none,id=source,file="$TEST_IMG"
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'qmp_capabilities' }" \
'return'
# Create snapshot
TEST_IMG="$TEST_IMG.overlay" _make_test_img -u -b "$TEST_IMG" -F $IMGFMT 1M
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'blockdev-snapshot-sync',
'arguments': { 'device': 'source',
'snapshot-file': '$TEST_IMG.overlay',
'format': '$IMGFMT',
'mode': 'existing' } }" \
'return'
# Write something to the snapshot
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'human-monitor-command',
'arguments': { 'command-line':
'qemu-io source \"write -P 3 128k 128k\"' } }" \
'return'
# Create target image
TEST_IMG="$TEST_IMG.target.overlay" _make_test_img -u -b "$TEST_IMG.target" \
-F $IMGFMT 1M
# Mirror snapshot
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'drive-mirror',
'arguments': { 'device': 'source',
'target': '$TEST_IMG.target.overlay',
'mode': 'existing',
'sync': 'top' } }" \
'return'
# Wait for convergence
_send_qemu_cmd $QEMU_HANDLE \
'' \
'BLOCK_JOB_READY'
# Write some more
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'human-monitor-command',
'arguments': { 'command-line':
'qemu-io source \"write -P 4 192k 64k\"' } }" \
'return'
# Copy source backing chain to the target before completing the job
cp "$TEST_IMG.backing" "$TEST_IMG.target.backing"
cp "$TEST_IMG" "$TEST_IMG.target"
$QEMU_IMG rebase -u -b "$TEST_IMG.target.backing" -F $IMGFMT "$TEST_IMG.target"
# Complete block job
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'block-job-complete',
'arguments': { 'device': 'source' } }" \
''
_send_qemu_cmd $QEMU_HANDLE \
'' \
'"status": "null"'
# Remove the source images
for img in "$TEST_IMG{,.backing,.overlay}"; do
_rm_test_img "$img"
done
echo
# Check online disk contents
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'human-monitor-command',
'arguments': { 'command-line':
'qemu-io source \"read -P 1 0k 64k\"' } }" \
'return'
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'human-monitor-command',
'arguments': { 'command-line':
'qemu-io source \"read -P 2 64k 64k\"' } }" \
'return'
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'human-monitor-command',
'arguments': { 'command-line':
'qemu-io source \"read -P 3 128k 64k\"' } }" \
'return'
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'human-monitor-command',
'arguments': { 'command-line':
'qemu-io source \"read -P 4 192k 64k\"' } }" \
'return'
echo
_send_qemu_cmd $QEMU_HANDLE \
"{ 'execute': 'quit' }" \
'return'
wait=1 _cleanup_qemu
echo
# Check offline disk contents
$QEMU_IO -c 'read -P 1 0k 64k' \
-c 'read -P 2 64k 64k' \
-c 'read -P 3 128k 64k' \
-c 'read -P 4 192k 64k' \
"$TEST_IMG.target.overlay" | _filter_qemu_io
echo
# success, all done
echo '*** done'
rm -f $seq.full
status=0