b66ff2c298
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>
127 lines
3.5 KiB
Bash
Executable File
127 lines
3.5 KiB
Bash
Executable File
#!/usr/bin/env bash
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#
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# Test case for relative backing file names in complex BDS trees
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#
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# Copyright (C) 2014 Red Hat, Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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#
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# creator
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owner=mreitz@redhat.com
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seq="$(basename $0)"
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echo "QA output created by $seq"
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status=1 # failure is the default!
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_cleanup()
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{
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_cleanup_test_img
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_rm_test_img "$TEST_IMG.copy"
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}
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trap "_cleanup; exit \$status" 0 1 2 3 15
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# get standard environment, filters and checks
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. ./common.rc
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. ./common.filter
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# Any format supporting backing files
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_supported_fmt qed qcow qcow2 vmdk
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_supported_proto file
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_unsupported_imgopts "subformat=monolithicFlat" "subformat=twoGbMaxExtentFlat" \
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"subformat=twoGbMaxExtentSparse"
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TEST_IMG_REL=$(basename "$TEST_IMG")
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echo
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echo '=== Reconstructable filename ==='
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echo
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TEST_IMG="$TEST_IMG.base" _make_test_img 64M
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_make_test_img -b "$TEST_IMG_REL.base" -F $IMGFMT 64M
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# qemu should be able to reconstruct the filename, so relative backing names
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# should work
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# (We have to filter the backing file format because vmdk always
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# reports it (as vmdk), whereas other image formats would do so only
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# with the backing_fmt creation option, which neither vmdk nor qcow
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# support)
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TEST_IMG="json:{'driver':'$IMGFMT','file':{'driver':'file','filename':'$TEST_IMG'}}" \
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_img_info | _filter_img_info | grep -v 'backing file format'
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echo
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echo '=== Non-reconstructable filename ==='
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echo
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# Across blkdebug without a config file, you cannot reconstruct filenames, so
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# qemu is incapable of knowing the directory of the top image from the filename
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# alone. However, using bdrv_dirname(), it should still work.
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# (Filter out the json:{} filename so this test works with external data files)
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TEST_IMG="json:{
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'driver': '$IMGFMT',
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'file': {
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'driver': 'blkdebug',
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'image': {
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'driver': 'file',
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'filename': '$TEST_IMG'
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},
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'set-state': [
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{
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'event': 'read_aio',
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'new_state': 42
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}
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]
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}
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}" _img_info | _filter_img_info | grep -v 'backing file format' \
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| _filter_json_filename
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echo
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echo '=== Backing name is always relative to the backed image ==='
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echo
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# omit the image size; it should work anyway
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_make_test_img -b "$TEST_IMG_REL.base" -F $IMGFMT
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echo
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echo '=== Nodes without a common directory ==='
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echo
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cp "$TEST_IMG" "$TEST_IMG.copy"
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# Should inform us that the actual path of the backing file cannot be determined
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TEST_IMG="json:{
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'driver': '$IMGFMT',
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'file': {
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'driver': 'quorum',
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'vote-threshold': 1,
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'children': [
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{
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'driver': 'file',
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'filename': '$TEST_IMG'
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},
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{
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'driver': 'file',
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'filename': '$TEST_IMG.copy'
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}
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]
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}
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}" _img_info | _filter_img_info | grep -v 'backing file format' \
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| _filter_json_filename
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# success, all done
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echo '*** done'
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rm -f $seq.full
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status=0
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