qemu/tests/qemu-iotests/267
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 which nodes are involved in internal snapshots
#
# Copyright (C) 2019 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 $seq"
status=1 # failure is the default!
_cleanup()
{
_cleanup_test_img
rm -f "$SOCK_DIR/nbd"
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common.rc
. ./common.filter
_supported_fmt qcow2
_supported_proto file
_supported_os Linux
_require_drivers copy-on-read
# Internal snapshots are (currently) impossible with refcount_bits=1,
# and generally impossible with external data files
_unsupported_imgopts 'refcount_bits=1[^0-9]' data_file
_require_devices virtio-blk
do_run_qemu()
{
echo Testing: "$@"
(
if ! test -t 0; then
while read cmd; do
echo $cmd
done
fi
echo quit
) | $QEMU -nographic -monitor stdio -nodefaults "$@"
echo
}
run_qemu()
{
do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qemu | _filter_hmp |
_filter_generated_node_ids | _filter_imgfmt | _filter_vmstate_size
}
size=128M
run_test()
{
if [ -n "$BACKING_FILE" ]; then
_make_test_img -b "$BACKING_FILE" -F $IMGFMT $size
else
_make_test_img $size
fi
printf "savevm snap0\ninfo snapshots\nloadvm snap0\n" | run_qemu "$@" | _filter_date
}
echo
echo "=== No block devices at all ==="
echo
run_test
echo
echo "=== -drive if=none ==="
echo
run_test -drive driver=file,file="$TEST_IMG",if=none
run_test -drive driver=$IMGFMT,file="$TEST_IMG",if=none
run_test -drive driver=$IMGFMT,file="$TEST_IMG",if=none -device virtio-blk,drive=none0
echo
echo "=== -drive if=virtio ==="
echo
run_test -drive driver=file,file="$TEST_IMG",if=virtio
run_test -drive driver=$IMGFMT,file="$TEST_IMG",if=virtio
echo
echo "=== Simple -blockdev ==="
echo
run_test -blockdev driver=file,filename="$TEST_IMG",node-name=file
run_test -blockdev driver=file,filename="$TEST_IMG",node-name=file \
-blockdev driver=$IMGFMT,file=file,node-name=fmt
run_test -blockdev driver=file,filename="$TEST_IMG",node-name=file \
-blockdev driver=raw,file=file,node-name=raw \
-blockdev driver=$IMGFMT,file=raw,node-name=fmt
echo
echo "=== -blockdev with a filter on top ==="
echo
run_test -blockdev driver=file,filename="$TEST_IMG",node-name=file \
-blockdev driver=$IMGFMT,file=file,node-name=fmt \
-blockdev driver=copy-on-read,file=fmt,node-name=filter
echo
echo "=== -blockdev with a backing file ==="
echo
TEST_IMG="$TEST_IMG.base" _make_test_img $size
BACKING_FILE="$TEST_IMG.base" \
run_test -blockdev driver=file,filename="$TEST_IMG.base",node-name=backing-file \
-blockdev driver=file,filename="$TEST_IMG",node-name=file \
-blockdev driver=$IMGFMT,file=file,backing=backing-file,node-name=fmt
BACKING_FILE="$TEST_IMG.base" \
run_test -blockdev driver=file,filename="$TEST_IMG.base",node-name=backing-file \
-blockdev driver=$IMGFMT,file=backing-file,node-name=backing-fmt \
-blockdev driver=file,filename="$TEST_IMG",node-name=file \
-blockdev driver=$IMGFMT,file=file,backing=backing-fmt,node-name=fmt
# A snapshot should be present on the overlay, but not the backing file
echo Internal snapshots on overlay:
$QEMU_IMG snapshot -l "$TEST_IMG" | _filter_date | _filter_vmstate_size
echo Internal snapshots on backing file:
$QEMU_IMG snapshot -l "$TEST_IMG.base" | _filter_date | _filter_vmstate_size
echo
echo "=== -blockdev with NBD server on the backing file ==="
echo
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $size
cat <<EOF |
nbd_server_start unix:$SOCK_DIR/nbd
nbd_server_add -w backing-fmt
savevm snap0
info snapshots
loadvm snap0
EOF
run_qemu -blockdev driver=file,filename="$TEST_IMG.base",node-name=backing-file \
-blockdev driver=$IMGFMT,file=backing-file,node-name=backing-fmt \
-blockdev driver=file,filename="$TEST_IMG",node-name=file \
-blockdev driver=$IMGFMT,file=file,backing=backing-fmt,node-name=fmt |
_filter_date
# This time, a snapshot should be created on both files
echo Internal snapshots on overlay:
$QEMU_IMG snapshot -l "$TEST_IMG" | _filter_date | _filter_vmstate_size
echo Internal snapshots on backing file:
$QEMU_IMG snapshot -l "$TEST_IMG.base" | _filter_date | _filter_vmstate_size
# success, all done
echo "*** done"
rm -f $seq.full
status=0