xemu/tests/qemu-iotests/024
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

206 lines
6.4 KiB
Bash
Executable File

#!/usr/bin/env bash
#
# Rebasing COW images
#
# Copyright (C) 2009 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 $seq"
status=1 # failure is the default!
_cleanup()
{
_cleanup_test_img
_rm_test_img "$TEST_DIR/t.$IMGFMT.base_old"
_rm_test_img "$TEST_DIR/t.$IMGFMT.base_new"
_rm_test_img "$TEST_DIR/subdir/t.$IMGFMT"
_rm_test_img "$TEST_DIR/subdir/t.$IMGFMT.base_old"
_rm_test_img "$TEST_DIR/subdir/t.$IMGFMT.base_new"
rmdir "$TEST_DIR/subdir" 2> /dev/null
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common.rc
. ./common.filter
. ./common.pattern
# Currently only qcow2 and qed support rebasing
_supported_fmt qcow2 qed
_supported_proto file
_supported_os Linux
CLUSTER_SIZE=65536
# Cluster allocations to be tested:
#
# Backing (old) 11 -- 11 -- 11 -- 11 --
# Backing (new) 22 22 -- -- 22 22 -- --
# COW image 33 33 33 33 -- -- -- --
#
# The pattern is written twice to have both an alloc -> non-alloc and a
# non-alloc -> alloc transition in the COW image.
echo "Creating backing file"
echo
TEST_IMG_SAVE="$TEST_IMG"
TEST_IMG="$TEST_IMG.base_old"
_make_test_img 1G
io_pattern writev 0 $CLUSTER_SIZE $((2 * CLUSTER_SIZE)) 8 0x11
TEST_IMG="$TEST_IMG_SAVE.base_new"
echo "Creating new backing file"
echo
_make_test_img 1G
io_pattern writev 0 $((2 * CLUSTER_SIZE)) $((4 * CLUSTER_SIZE)) 4 0x22
TEST_IMG="$TEST_IMG_SAVE"
echo "Creating COW image"
echo
_make_test_img -b "$TEST_IMG.base_old" -F $IMGFMT 1G
io_pattern writev 0 $((4 * CLUSTER_SIZE)) 0 1 0x33
io_pattern writev $((8 * CLUSTER_SIZE)) $((4 * CLUSTER_SIZE)) 0 1 0x33
echo "Read before the rebase to make sure everything is set up correctly"
echo
io_pattern readv $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((4 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((5 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((6 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((7 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((8 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((9 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((10 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((11 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((12 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((13 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((14 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((15 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
echo
echo Rebase and test again
echo
$QEMU_IMG rebase -b "$TEST_IMG.base_new" -F $IMGFMT "$TEST_IMG"
io_pattern readv $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((4 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((5 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((6 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((7 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((8 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((9 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((10 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((11 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x33
io_pattern readv $((12 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((13 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
io_pattern readv $((14 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x11
io_pattern readv $((15 * CLUSTER_SIZE)) $CLUSTER_SIZE 0 1 0x00
echo
echo "=== Test rebase in a subdirectory of the working directory ==="
echo
# Clean up the old images beforehand so they do not interfere with
# this test
_cleanup
mkdir "$TEST_DIR/subdir"
# Relative to the overlay
BASE_OLD_OREL="t.$IMGFMT.base_old"
BASE_NEW_OREL="t.$IMGFMT.base_new"
# Relative to $TEST_DIR (which is going to be our working directory)
OVERLAY_WREL="subdir/t.$IMGFMT"
BASE_OLD="$TEST_DIR/subdir/$BASE_OLD_OREL"
BASE_NEW="$TEST_DIR/subdir/$BASE_NEW_OREL"
OVERLAY="$TEST_DIR/$OVERLAY_WREL"
# Test done here:
#
# Backing (old): 11 11 -- 11
# Backing (new): -- 22 22 11
# Overlay: -- -- -- --
#
# Rebasing works, we have verified that above. Here, we just want to
# see that rebasing is done for the correct target backing file.
TEST_IMG=$BASE_OLD _make_test_img 1M
TEST_IMG=$BASE_NEW _make_test_img 1M
TEST_IMG=$OVERLAY _make_test_img -b "$BASE_OLD_OREL" -F $IMGFMT 1M
echo
$QEMU_IO "$BASE_OLD" \
-c "write -P 0x11 $((0 * CLUSTER_SIZE)) $((2 * CLUSTER_SIZE))" \
-c "write -P 0x11 $((3 * CLUSTER_SIZE)) $((1 * CLUSTER_SIZE))" \
| _filter_qemu_io
$QEMU_IO "$BASE_NEW" \
-c "write -P 0x22 $((1 * CLUSTER_SIZE)) $((2 * CLUSTER_SIZE))" \
-c "write -P 0x11 $((3 * CLUSTER_SIZE)) $((1 * CLUSTER_SIZE))" \
| _filter_qemu_io
echo
pushd "$TEST_DIR" >/dev/null
$QEMU_IMG rebase -f "$IMGFMT" -b "$BASE_NEW_OREL" -F $IMGFMT "$OVERLAY_WREL"
popd >/dev/null
# Verify the backing path is correct
TEST_IMG=$OVERLAY _img_info | grep '^backing file:'
echo
# Verify the data is correct
$QEMU_IO "$OVERLAY" \
-c "read -P 0x11 $((0 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
-c "read -P 0x11 $((1 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
-c "read -P 0x00 $((2 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
-c "read -P 0x11 $((3 * CLUSTER_SIZE)) $CLUSTER_SIZE" \
| _filter_qemu_io
echo
# Verify that cluster #3 is not allocated (because it is the same in
# $BASE_OLD and $BASE_NEW)
$QEMU_IMG map "$OVERLAY" | _filter_qemu_img_map
# success, all done
echo "*** done"
rm -f $seq.full
status=0