qemu-e2k/tests/qemu-iotests/038
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 with AIO
#
# 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 $seq"
status=1 # failure is the default!
_cleanup()
{
_cleanup_test_img
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common.rc
. ./common.filter
_supported_fmt qcow2 qed
_supported_proto file
_supported_os Linux
CLUSTER_SIZE=2M
size=128M
echo
echo "== creating backing file for COW tests =="
TEST_IMG_SAVE="$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 in $(seq 0 $((sectors - 1))); do
cur_sec=$((offset / 65536 + i))
pattern=$(( ( (cur_sec % 128) + (cur_sec / 128)) % 128 ))
echo "$op -P $pattern $((cur_sec * 64))k 64k"
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 "== Some concurrent requests touching the same cluster =="
overlay_io()
{
# Start with a request touching two clusters
echo aio_write -P 0x80 2020k 80k
# Then add some requests all over the place
for i in $(seq 0 15; seq 17 31; seq 33 47); do
echo aio_write -P $((0x81 + i)) $((i * 128))k 64k
done
# Then backwards overwriting part of them
for i in $( (seq 0 15; seq 17 31; seq 33 47) | tac); do
echo aio_write -P $((0x81 + i)) $((i * 128 + 32))k 64k
done
# And finally crossing the next cluster boundary
echo aio_write -P 0x90 4080k 80k
}
overlay_io | $QEMU_IO "$TEST_IMG" | _filter_qemu_io |\
sed -e 's/bytes at offset [0-9]*/bytes at offset XXX/g' \
-e 's/qemu-io> //g' | paste - - | sort | tr '\t' '\n'
echo
echo "== Verify image content =="
verify_io()
{
echo read -P 31 2016k 4k
echo read -P 0x80 2020k 80k
echo read -P 32 2100k 12k
echo read -P 33 2112k 64k
echo read -P 63 4064k 16k
echo read -P 0x90 4080k 80k
echo read -P 65 4160k 64k
for i in $(seq 0 15; seq 17 31; seq 33 47); do
echo read -P $((0x81 + i)) $((i * 128))k 96k
done
for i in $(seq 0 14; seq 16 30; seq 32 47); do
local cur_sec=$(( i * 2 + 1 ))
local pattern=$(( ( (cur_sec % 128) + (cur_sec / 128)) % 128 ))
echo read -P $pattern $((i * 128 + 96))k 32k
done
}
verify_io | $QEMU_IO "$TEST_IMG" | _filter_qemu_io
_check_test_img
# success, all done
echo "*** done"
rm -f $seq.full
status=0