qemu-e2k/tests/qemu-iotests/037
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 COW from backing files
#
# Copyright (C) 2012 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 $seq"
status=1 # failure is the default!
_cleanup()
{
_cleanup_test_img
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common.rc
. ./common.filter
_supported_fmt qcow qcow2 vmdk qed
_supported_proto file
_unsupported_imgopts "subformat=monolithicFlat" \
"subformat=twoGbMaxExtentFlat" \
"subformat=twoGbMaxExtentSparse" \
"subformat=streamOptimized"
CLUSTER_SIZE=4k
size=128M
echo
echo "== creating backing file for COW tests =="
TEST_IMG_SAVE="$TEST_IMG"
TEST_IMG="$TEST_IMG.base"
_make_test_img $size
backing_io()
{
local offset=$1
local sectors=$2
local op=$3
local pattern=0
local cur_sec=0
for ((i=0;i<=$((sectors - 1));i++)); do
cur_sec=$((offset / 512 + i))
pattern=$(( ( (cur_sec % 256) + (cur_sec / 256)) % 256 ))
echo "$op -P $pattern $((cur_sec * 512)) 512"
done
}
backing_io 0 256 write | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
TEST_IMG="$TEST_IMG_SAVE"
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT 6G
echo
echo "== COW in a single cluster =="
$QEMU_IO -c "write -P 0x77 0 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -P 0x88 6k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -P 0x99 9k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x77 0 2k" "$TEST_IMG" | _filter_qemu_io
backing_io $((2 * 1024)) 8 read | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x88 6k 2k" "$TEST_IMG" | _filter_qemu_io
backing_io $((8 * 1024)) 2 read | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x99 9k 2k" "$TEST_IMG" | _filter_qemu_io
backing_io $((11 * 1024)) 2 read | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
echo
echo "== COW in two-cluster allocations =="
$QEMU_IO -c "write -P 0x77 16k 6k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -P 0x88 26k 6k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -P 0x99 33k 5k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x77 16k 6k" "$TEST_IMG" | _filter_qemu_io
backing_io $((22 * 1024)) 8 read | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x88 26k 6k" "$TEST_IMG" | _filter_qemu_io
backing_io $((32 * 1024)) 2 read | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x99 33k 5k" "$TEST_IMG" | _filter_qemu_io
backing_io $((38 * 1024)) 4 read | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
echo
echo "== COW in multi-cluster allocations =="
$QEMU_IO -c "write -P 0x77 48k 15k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -P 0x88 66k 14k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -P 0x99 83k 15k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x77 48k 15k" "$TEST_IMG" | _filter_qemu_io
backing_io $((63 * 1024)) 6 read | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x88 66k 14k" "$TEST_IMG" | _filter_qemu_io
backing_io $((80 * 1024)) 6 read | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x99 83k 15k" "$TEST_IMG" | _filter_qemu_io
backing_io $((98 * 1024)) 4 read | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
_check_test_img
# success, all done
echo "*** done"
rm -f $seq.full
status=0