qemu-img: Require -F with -b backing image

Back in commit d9f059aa6c (qemu-img: Deprecate use of -b without -F),
we deprecated the ability to create a file with a backing image that
requires qemu to perform format probing.  Qemu can still probe older
files for backwards compatibility, but it is time to finish off the
ability to create such images, due to the potential security risk they
present.  Update a couple of iotests affected by the change.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210503213600.569128-3-eblake@redhat.com>
Reviewed-by: Connor Kuehl <ckuehl@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Eric Blake 2021-05-03 14:36:00 -07:00 committed by Kevin Wolf
parent 5a385bf5c5
commit 497a30dbb0
10 changed files with 56 additions and 85 deletions

View file

@ -920,8 +920,8 @@ class TestCommitWithOverriddenBacking(iotests.QMPTestCase):
def setUp(self):
qemu_img('create', '-f', iotests.imgfmt, self.img_base_a, '1M')
qemu_img('create', '-f', iotests.imgfmt, self.img_base_b, '1M')
qemu_img('create', '-f', iotests.imgfmt, '-b', self.img_base_a, \
self.img_top)
qemu_img('create', '-f', iotests.imgfmt, '-b', self.img_base_a,
'-F', iotests.imgfmt, self.img_top)
self.vm = iotests.VM()
self.vm.launch()

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@ -1295,8 +1295,10 @@ class TestReplaces(iotests.QMPTestCase):
class TestFilters(iotests.QMPTestCase):
def setUp(self):
qemu_img('create', '-f', iotests.imgfmt, backing_img, '1M')
qemu_img('create', '-f', iotests.imgfmt, '-b', backing_img, test_img)
qemu_img('create', '-f', iotests.imgfmt, '-b', backing_img, target_img)
qemu_img('create', '-f', iotests.imgfmt, '-b', backing_img,
'-F', iotests.imgfmt, test_img)
qemu_img('create', '-f', iotests.imgfmt, '-b', backing_img,
'-F', iotests.imgfmt, target_img)
qemu_io('-c', 'write -P 1 0 512k', backing_img)
qemu_io('-c', 'write -P 2 512k 512k', test_img)

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@ -44,16 +44,16 @@ _supported_os Linux
# qcow2.py does not work too well with external data files
_unsupported_imgopts data_file
# Intentionally specify backing file without backing format; demonstrate
# the difference in warning messages when backing file could be probed.
# Note that only a non-raw probe result will affect the resulting image.
# Older qemu-img could set up backing file without backing format; modern
# qemu can't but we can use qcow2.py to simulate older files.
truncate -s $((64 * 1024 * 1024)) "$TEST_IMG.orig"
_make_test_img -b "$TEST_IMG.orig" 64M
_make_test_img -b "$TEST_IMG.orig" -F raw 64M
$PYTHON qcow2.py "$TEST_IMG" del-header-ext 0xE2792ACA
TEST_IMG="$TEST_IMG.base" _make_test_img 64M
$QEMU_IMG convert -O qcow2 -B "$TEST_IMG.orig" "$TEST_IMG.orig" "$TEST_IMG"
_make_test_img -b "$TEST_IMG.base" 64M
_make_test_img -u -b "$TEST_IMG.base" 64M
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT 64M
_make_test_img -u -b "$TEST_IMG.base" -F $IMGFMT 64M
# Set an invalid backing file format
$PYTHON qcow2.py "$TEST_IMG" add-header-ext 0xE2792ACA "foo"
@ -64,9 +64,9 @@ _img_info
$QEMU_IO -c "open $TEST_IMG" -c "read 0 4k" 2>&1 | _filter_qemu_io | _filter_testdir
$QEMU_IO -c "open -o backing.driver=$IMGFMT $TEST_IMG" -c "read 0 4k" | _filter_qemu_io
# Rebase the image, to show that omitting backing format triggers a warning,
# but probing now lets us use the backing file.
$QEMU_IMG rebase -u -b "$TEST_IMG.base" "$TEST_IMG"
# Rebase the image, to show that backing format is required.
($QEMU_IMG rebase -u -b "$TEST_IMG.base" "$TEST_IMG" 2>&1 && echo "unexpected pass") | _filter_testdir
$QEMU_IMG rebase -u -b "$TEST_IMG.base" -F $IMGFMT "$TEST_IMG"
$QEMU_IO -c "open $TEST_IMG" -c "read 0 4k" 2>&1 | _filter_qemu_io | _filter_testdir
# success, all done

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@ -1,12 +1,9 @@
QA output created by 114
qemu-img: warning: Deprecated use of backing file without explicit backing format (detected format of raw)
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.orig
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.orig backing_fmt=raw
Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=67108864
qemu-img: warning: Deprecated use of backing file without explicit backing format
qemu-img: warning: Deprecated use of backing file without explicit backing format (detected format of IMGFMT)
qemu-img: Use of backing file requires explicit backing format
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
qemu-img: warning: Deprecated use of unopened backing file without explicit backing format, use of this image requires potentially unsafe format probing
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base
image: TEST_DIR/t.IMGFMT
file format: IMGFMT
virtual size: 64 MiB (67108864 bytes)
@ -17,7 +14,7 @@ qemu-io: can't open device TEST_DIR/t.qcow2: Could not open backing file: Unknow
no file open, try 'help open'
read 4096/4096 bytes at offset 0
4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
qemu-img: warning: Deprecated use of backing file without explicit backing format, use of this image requires potentially unsafe format probing
qemu-img: Could not change the backing file to 'TEST_DIR/t.qcow2.base': Invalid argument
read 4096/4096 bytes at offset 0
4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
*** done

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@ -3,7 +3,7 @@
#
# Test qcow backing file warnings
#
# Copyright (C) 2020 Red Hat, Inc.
# Copyright (C) 2020-2021 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
@ -46,7 +46,6 @@ echo "== qcow backed by qcow =="
TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base" $size
_img_info
_make_test_img -b "$TEST_IMG.base" -F $IMGFMT $size
_img_info
@ -71,7 +70,6 @@ echo "== qcow backed by raw =="
rm "$TEST_IMG.base"
truncate --size=$size "$TEST_IMG.base"
_make_test_img -b "$TEST_IMG.base" $size
_img_info
_make_test_img -b "$TEST_IMG.base" -F raw $size
_img_info

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@ -2,13 +2,7 @@ QA output created by 301
== qcow backed by qcow ==
Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=33554432
qemu-img: warning: Deprecated use of backing file without explicit backing format (detected format of IMGFMT)
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
image: TEST_DIR/t.IMGFMT
file format: IMGFMT
virtual size: 32 MiB (33554432 bytes)
cluster_size: 512
backing file: TEST_DIR/t.IMGFMT.base
qemu-img: TEST_DIR/t.IMGFMT: Backing file specified without backing format
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
image: TEST_DIR/t.IMGFMT
file format: IMGFMT
@ -36,13 +30,7 @@ cluster_size: 512
backing file: TEST_DIR/t.IMGFMT.base
== qcow backed by raw ==
qemu-img: warning: Deprecated use of backing file without explicit backing format (detected format of raw)
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base
image: TEST_DIR/t.IMGFMT
file format: IMGFMT
virtual size: 32 MiB (33554432 bytes)
cluster_size: 512
backing file: TEST_DIR/t.IMGFMT.base
qemu-img: TEST_DIR/t.IMGFMT: Backing file specified without backing format
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=raw
image: TEST_DIR/t.IMGFMT
file format: IMGFMT