qemu-e2k/tests/qemu-iotests/097
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

127 lines
4.6 KiB
Bash
Executable File

#!/usr/bin/env bash
#
# Commit changes into backing chains and empty the top image if the
# backing image is not explicitly specified
#
# Copyright (C) 2014 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 $seq"
status=1 # failure is the default!
_cleanup()
{
_cleanup_test_img
_rm_test_img "$TEST_IMG.itmd"
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common.rc
. ./common.filter
. ./common.pattern
# Any format supporting backing files and bdrv_make_empty
_supported_fmt qcow qcow2
_supported_proto file
_supported_os Linux
# Four main passes:
# 0: Two-layer backing chain, commit to upper backing file (implicitly)
# (in this case, the top image will be emptied)
# 1: Two-layer backing chain, commit to upper backing file (explicitly)
# (in this case, the top image will implicitly stay unchanged)
# 2: Two-layer backing chain, commit to upper backing file (implicitly with -d)
# (in this case, the top image will explicitly stay unchanged)
# 3: Two-layer backing chain, commit to lower backing file
# (in this case, the top image will implicitly stay unchanged)
#
# 020 already tests committing, so this only tests whether image chains are
# working properly and that all images above the base are emptied; therefore,
# no complicated patterns are necessary. Check near the 2G mark, as qcow2
# has been buggy at that boundary in the past.
for i in 0 1 2 3; do
echo
echo "=== Test pass $i ==="
echo
len=$((2100 * 1024 * 1024 + 512)) # larger than 2G, and not cluster aligned
TEST_IMG="$TEST_IMG.base" _make_test_img $len
TEST_IMG="$TEST_IMG.itmd" _make_test_img -b "$TEST_IMG.base" -F $IMGFMT $len
_make_test_img -b "$TEST_IMG.itmd" -F $IMGFMT $len
$QEMU_IO -c "write -P 1 0x7ffd0000 192k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -P 2 0x7ffe0000 128k" "$TEST_IMG.itmd" | _filter_qemu_io
$QEMU_IO -c "write -P 3 0x7fff0000 64k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -P 4 $(($len - 512)) 512" "$TEST_IMG" | _filter_qemu_io
if [ $i -lt 3 ]; then
if [ $i == 0 ]; then
# -b "$TEST_IMG.itmd" should be the default (that is, committing to the
# first backing file in the chain)
$QEMU_IMG commit "$TEST_IMG"
elif [ $i == 1 ]; then
# explicitly specify the commit target (this should imply -d)
$QEMU_IMG commit -b "$TEST_IMG.itmd" "$TEST_IMG"
else
# do not explicitly specify the commit target, but use -d to leave the
# top image unchanged
$QEMU_IMG commit -d "$TEST_IMG"
fi
# Bottom should be unchanged
$QEMU_IO -c 'read -P 1 0x7ffd0000 192k' "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "read -P 0 $((len - 512)) 512" "$TEST_IMG.base" | _filter_qemu_io
# Intermediate should contain changes from top
$QEMU_IO -c 'read -P 1 0x7ffd0000 64k' "$TEST_IMG.itmd" | _filter_qemu_io
$QEMU_IO -c 'read -P 2 0x7ffe0000 64k' "$TEST_IMG.itmd" | _filter_qemu_io
$QEMU_IO -c 'read -P 3 0x7fff0000 64k' "$TEST_IMG.itmd" | _filter_qemu_io
$QEMU_IO -c "read -P 4 $((len - 512)) 512" "$TEST_IMG.itmd" | _filter_qemu_io
# And in pass 0, the top image should be empty, whereas in both other passes
# it should be unchanged (which is both checked by qemu-img map)
else
$QEMU_IMG commit -b "$TEST_IMG.base" "$TEST_IMG"
# Bottom should contain all changes
$QEMU_IO -c 'read -P 1 0x7ffd0000 64k' "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c 'read -P 2 0x7ffe0000 64k' "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c 'read -P 3 0x7fff0000 64k' "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "read -P 4 $((len - 512)) 512" "$TEST_IMG.base" | _filter_qemu_io
# Both top and intermediate should be unchanged
fi
$QEMU_IMG map "$TEST_IMG.base" | _filter_qemu_img_map
$QEMU_IMG map "$TEST_IMG.itmd" | _filter_qemu_img_map
$QEMU_IMG map "$TEST_IMG" | _filter_qemu_img_map
done
# success, all done
echo "*** done"
rm -f $seq.full
status=0