oslo.utils/oslo_utils/tests/imageutils/test_format_inspector.py
Dan Smith e927ac2ecb Squelch irrelevant format complaints
When we're eating a multi-inspector stream, we would expect the other
formats to fail at some point in the stream when they don't match.
This makes us not log the irrelevant format failures when we're
looking for a specific one. We were already logging that at debug
level for the sake of visibility into the process, but some people
have been misled by the complaint. In addition, soften the language
a bit to make it clear it's not an actual failure.

Change-Id: Ife973cead13eba0900b72d9234253d543f723636
2024-09-20 11:55:19 -07:00

1103 lines
44 KiB
Python

# Copyright 2020 Red Hat, Inc
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import io
import os
import struct
import subprocess
import tempfile
from unittest import mock
import ddt
from oslo_utils import units
from oslo_utils.imageutils import format_inspector
from oslo_utils.imageutils import QemuImgInfo
from oslotest import base as test_base
TEST_IMAGE_PREFIX = 'oslo-unittest-formatinspector-'
def get_size_format_from_qemu_img(filename):
output = subprocess.check_output(
'qemu-img info --output=json "%s"' % filename,
shell=True)
info = QemuImgInfo(output, format='json')
return info.virtual_size, info.file_format
@ddt.ddt
class TestFormatInspectors(test_base.BaseTestCase):
def setUp(self):
super(TestFormatInspectors, self).setUp()
self._created_files = []
def tearDown(self):
super(TestFormatInspectors, self).tearDown()
for fn in self._created_files:
try:
os.remove(fn)
except Exception:
pass
def _create_iso(self, image_size, subformat='9660'):
"""Create an ISO file of the given size.
:param image_size: The size of the image to create in bytes
:param subformat: The subformat to use, if any
"""
# these tests depend on mkisofs
# being installed and in the path,
# if it is not installed, skip
try:
subprocess.check_output('mkisofs --version', shell=True)
except Exception:
self.skipTest('mkisofs not installed')
size = image_size // units.Mi
base_cmd = "mkisofs"
if subformat == 'udf':
# depending on the distribution mkisofs may not support udf
# and may be provided by genisoimage instead. As a result we
# need to check if the command supports udf via help
# instead of checking the installed version.
# mkisofs --help outputs to stderr so we need to
# redirect it to stdout to use grep.
try:
subprocess.check_output(
'mkisofs --help 2>&1 | grep udf', shell=True)
except Exception:
self.skipTest('mkisofs does not support udf format')
base_cmd += " -udf"
prefix = TEST_IMAGE_PREFIX
prefix += '-%s-' % subformat
fn = tempfile.mktemp(prefix=prefix, suffix='.iso')
self._created_files.append(fn)
subprocess.check_output(
'dd if=/dev/zero of=%s bs=1M count=%i' % (fn, size),
shell=True)
# We need to use different file as input and output as the behavior
# of mkisofs is version dependent if both the input and the output
# are the same and can cause test failures
out_fn = "%s.iso" % fn
subprocess.check_output(
'%s -V "TEST" -o %s %s' % (base_cmd, out_fn, fn),
shell=True)
self._created_files.append(out_fn)
return out_fn
def _create_gpt(self, image_size, subformat='gpt'):
data = bytearray(b'\x00' * 512 * 10)
# The last two bytes of the first sector is the little-endian signature
# value 0xAA55
data[510:512] = b'\x55\xAA'
# This is one EFI Protective MBR partition in the first PTE slot,
# which is 16 bytes starting at offset 446.
data[446:446 + 16] = struct.pack('<BBBBBBBBII',
0x00, # boot
0x00, # start C
0x02, # start H
0x00, # start S
0xEE, # OS type
0x00, # end C
0x00, # end H
0x00, # end S
0x01, # start LBA
0x00, # size LBA
)
fn = tempfile.mktemp(prefix='%s-gpt-%s' % (TEST_IMAGE_PREFIX,
subformat))
with open(fn, 'wb') as f:
f.write(data)
self._created_files.append(fn)
return fn
def _create_img(
self, fmt, size, subformat=None, options=None,
backing_file=None):
"""Create an image file of the given format and size.
:param fmt: The format to create
:param size: The size of the image to create in bytes
:param subformat: The subformat to use, if any
:param options: A dictionary of options to pass to the format
:param backing_file: The backing file to use, if any
"""
if fmt == 'iso':
return self._create_iso(size, subformat)
if fmt == 'gpt':
return self._create_gpt(size, subformat)
if fmt == 'vhd':
# QEMU calls the vhd format vpc
fmt = 'vpc'
# these tests depend on qemu-img being installed and in the path,
# if it is not installed, skip. we also need to ensure that the
# format is supported by qemu-img, this can vary depending on the
# distribution so we need to check if the format is supported via
# the help output.
try:
subprocess.check_output(
'qemu-img --help | grep %s' % fmt, shell=True)
except Exception:
self.skipTest(
'qemu-img not installed or does not support %s format' % fmt)
if options is None:
options = {}
opt = ''
prefix = TEST_IMAGE_PREFIX
if subformat:
options['subformat'] = subformat
prefix += subformat + '-'
if options:
opt += '-o ' + ','.join('%s=%s' % (k, v)
for k, v in options.items())
if backing_file is not None:
opt += ' -b %s -F raw' % backing_file
fn = tempfile.mktemp(prefix=prefix,
suffix='.%s' % fmt)
self._created_files.append(fn)
subprocess.check_output(
'qemu-img create -f %s %s %s %i' % (fmt, opt, fn, size),
shell=True)
return fn
def _create_allocated_vmdk(self, size_mb, subformat=None):
# We need a "big" VMDK file to exercise some parts of the code of the
# format_inspector. A way to create one is to first create an empty
# file, and then to convert it with the -S 0 option.
if subformat is None:
# Matches qemu-img default, see `qemu-img convert -O vmdk -o help`
subformat = 'monolithicSparse'
prefix = TEST_IMAGE_PREFIX
prefix += '-%s-' % subformat
fn = tempfile.mktemp(prefix=prefix, suffix='.vmdk')
self._created_files.append(fn)
raw = tempfile.mktemp(prefix=prefix, suffix='.raw')
self._created_files.append(raw)
# Create a file with pseudo-random data, otherwise it will get
# compressed in the streamOptimized format
subprocess.check_output(
'dd if=/dev/urandom of=%s bs=1M count=%i' % (raw, size_mb),
shell=True)
# Convert it to VMDK
subprocess.check_output(
'qemu-img convert -f raw -O vmdk -o subformat=%s -S 0 %s %s' % (
subformat, raw, fn),
shell=True)
return fn
def _test_format_at_block_size(self, format_name, img, block_size):
wrapper = format_inspector.InspectWrapper(open(img, 'rb'),
format_name)
while True:
chunk = wrapper.read(block_size)
if not chunk:
break
wrapper.close()
self.assertIsNotNone(wrapper.format, 'Failed to detect format')
return wrapper.format
def _test_format_at_image_size(self, format_name, image_size,
subformat=None, safety_check=False):
"""Test the format inspector for the given format at the
given image size.
:param format_name: The format to test
:param image_size: The size of the image to create in bytes
:param subformat: The subformat to use, if any
"""
img = self._create_img(format_name, image_size, subformat=subformat)
# Some formats have internal alignment restrictions making this not
# always exactly like image_size, so get the real value for comparison
virtual_size, _ = get_size_format_from_qemu_img(img)
# Read the format in various sizes, some of which will read whole
# sections in a single read, others will be completely unaligned, etc.
block_sizes = [64 * units.Ki, 1 * units.Mi]
# ISO images have a 32KB system area at the beginning of the image
# as a result reading that in 17 or 512 byte blocks takes too long,
# causing the test to fail. The 64KiB block size is enough to read
# the system area and header in a single read. the 1MiB block size
# adds very little time to the test so we include it.
if format_name != 'iso':
block_sizes.extend([17, 512])
for block_size in block_sizes:
fmt = self._test_format_at_block_size(format_name, img, block_size)
self.assertTrue(fmt.format_match,
'Failed to match %s at size %i block %i' % (
format_name, image_size, block_size))
self.assertEqual(virtual_size, fmt.virtual_size,
('Failed to calculate size for %s at size %i '
'block %i') % (format_name, image_size,
block_size))
memory = sum(fmt.context_info.values())
self.assertLess(memory, 512 * units.Ki,
'Format used more than 512KiB of memory: %s' % (
fmt.context_info))
if safety_check:
fmt.safety_check()
# If the safety check is supposed to pass, we can also make
# sure our detection works
det = format_inspector.detect_file_format(img)
self.assertEqual(det.__class__, fmt.__class__)
def _test_format(self, format_name, subformat=None):
# Try a few different image sizes, including some odd and very small
# sizes
for image_size in (512, 513, 2057, 7):
self._test_format_at_image_size(format_name, image_size * units.Mi,
subformat=subformat,
safety_check=True)
@ddt.data('qcow2', 'vhd', 'vhdx', 'vmdk', 'gpt')
def test_format(self, format):
self._test_format(format)
@ddt.unpack
@ddt.data(('iso', 'iso9660'), ('iso', 'udf'), ('vmdk', 'streamOptimized'))
def test_subformat(self, format, subformat):
self._test_format(format, subformat=subformat)
def _generate_bad_iso(self):
# we want to emulate a malicious user who uploads a an
# ISO file has a qcow2 header in the system area
# of the ISO file
# we will create a qcow2 image and an ISO file
# and then copy the qcow2 header to the ISO file
# e.g.
# mkisofs -o orig.iso /etc/resolv.conf
# qemu-img create orig.qcow2 -f qcow2 64M
# dd if=orig.qcow2 of=outcome bs=32K count=1
# dd if=orig.iso of=outcome bs=32K skip=1 seek=1
qcow = self._create_img('qcow2', 10 * units.Mi)
iso = self._create_iso(64 * units.Mi, subformat='9660')
# first ensure the files are valid
iso_fmt = self._test_format_at_block_size('iso', iso, 4 * units.Ki)
self.assertTrue(iso_fmt.format_match)
qcow_fmt = self._test_format_at_block_size('qcow2', qcow, 4 * units.Ki)
self.assertTrue(qcow_fmt.format_match)
# now copy the qcow2 header to an ISO file
prefix = TEST_IMAGE_PREFIX
prefix += '-bad-'
fn = tempfile.mktemp(prefix=prefix, suffix='.iso')
self._created_files.append(fn)
subprocess.check_output(
'dd if=%s of=%s bs=32K count=1' % (qcow, fn),
shell=True)
subprocess.check_output(
'dd if=%s of=%s bs=32K skip=1 seek=1' % (iso, fn),
shell=True)
return qcow, iso, fn
def test_bad_iso_qcow2(self):
# Test that an iso with a qcow2 header in the system area will be
# rejected because it matches more than one format (iso and qcow2).
# This is an important case because qemu-img does not support iso,
# and can be fooled into thinking one is a qcow2 by putting the header
# for one in ISO9660's "system area", which is technically a valid
# thing to do.
_, _, fn = self._generate_bad_iso()
self.assertRaisesRegex(format_inspector.ImageFormatError,
'Multiple formats detected',
self._test_format_at_block_size,
'iso', fn, 4 * units.Ki)
def test_from_file_reads_minimum(self):
img = self._create_img('qcow2', 10 * units.Mi)
file_size = os.stat(img).st_size
fmt = format_inspector.QcowInspector.from_file(img)
# We know everything we need from the first 512 bytes of a QCOW image,
# so make sure that we did not read the whole thing when we inspect
# a local file.
self.assertLess(fmt.actual_size, file_size)
def test_qed_always_unsafe(self):
img = self._create_img('qed', 10 * units.Mi)
fmt = format_inspector.get_inspector('qed').from_file(img)
self.assertTrue(fmt.format_match)
self.assertRaises(format_inspector.SafetyCheckFailed,
fmt.safety_check)
def test_vmdk_non_sparse_unsafe(self):
img = self._create_img('vmdk', 10 * units.Mi,
subformat='monolithicFlat')
fmt = format_inspector.detect_file_format(img)
self.assertEqual('vmdk', fmt.NAME)
e = self.assertRaises(format_inspector.SafetyCheckFailed,
fmt.safety_check)
self.assertIn('Unsupported subformat', str(e.failures['descriptor']))
def _test_vmdk_bad_descriptor_offset(self, subformat=None):
format_name = 'vmdk'
image_size = 10 * units.Mi
descriptorOffsetAddr = 0x1c
BAD_ADDRESS = 0x400
img = self._create_img(format_name, image_size, subformat=subformat)
# Corrupt the header
fd = open(img, 'r+b')
fd.seek(descriptorOffsetAddr)
fd.write(struct.pack('<Q', BAD_ADDRESS // 512))
fd.close()
# Read the format in various sizes, some of which will read whole
# sections in a single read, others will be completely unaligned, etc.
for block_size in (64 * units.Ki, 512, 17, 1 * units.Mi):
self.assertRaisesRegex(format_inspector.ImageFormatError,
'Wrong descriptor location',
self._test_format_at_block_size,
'vmdk', img, block_size)
def test_vmdk_bad_descriptor_offset(self):
self._test_vmdk_bad_descriptor_offset()
def test_vmdk_bad_descriptor_offset_stream_optimized(self):
self._test_vmdk_bad_descriptor_offset(subformat='streamOptimized')
def _test_vmdk_bad_descriptor_mem_limit(self, subformat=None):
format_name = 'vmdk'
image_size = 5 * units.Mi
virtual_size = 5 * units.Mi
descriptorOffsetAddr = 0x1c
descriptorSizeAddr = descriptorOffsetAddr + 8
twoMBInSectors = (2 << 20) // 512
# We need a big VMDK because otherwise we will not have enough data to
# fill-up the CaptureRegion.
img = self._create_allocated_vmdk(image_size // units.Mi,
subformat=subformat)
# Corrupt the end of descriptor address so it "ends" at 2MB
fd = open(img, 'r+b')
fd.seek(descriptorSizeAddr)
fd.write(struct.pack('<Q', twoMBInSectors))
fd.close()
# Read the format in various sizes, some of which will read whole
# sections in a single read, others will be completely unaligned, etc.
for block_size in (64 * units.Ki, 512, 17, 1 * units.Mi):
fmt = self._test_format_at_block_size(format_name, img, block_size)
self.assertTrue(fmt.format_match,
'Failed to match %s at size %i block %i' % (
format_name, image_size, block_size))
self.assertEqual(virtual_size, fmt.virtual_size,
('Failed to calculate size for %s at size %i '
'block %i') % (format_name, image_size,
block_size))
memory = sum(fmt.context_info.values())
self.assertLess(memory, 1.5 * units.Mi,
'Format used more than 1.5MiB of memory: %s' % (
fmt.context_info))
def test_vmdk_bad_descriptor_mem_limit(self):
self._test_vmdk_bad_descriptor_mem_limit()
def test_vmdk_bad_descriptor_mem_limit_stream_optimized(self):
self._test_vmdk_bad_descriptor_mem_limit(subformat='streamOptimized')
def test_qcow2_safety_checks(self):
# Create backing and data-file names (and initialize the backing file)
backing_fn = tempfile.mktemp(prefix='backing')
self._created_files.append(backing_fn)
with open(backing_fn, 'w') as f:
f.write('foobar')
data_fn = tempfile.mktemp(prefix='data')
self._created_files.append(data_fn)
# A qcow with no backing or data file is safe
fn = self._create_img('qcow2', 5 * units.Mi, None)
inspector = format_inspector.QcowInspector.from_file(fn)
inspector.safety_check()
# A backing file makes it unsafe
fn = self._create_img('qcow2', 5 * units.Mi, None,
backing_file=backing_fn)
inspector = format_inspector.QcowInspector.from_file(fn)
self.assertRaisesRegex(format_inspector.SafetyCheckFailed,
'.*backing_file.*',
inspector.safety_check)
# A data-file makes it unsafe
fn = self._create_img('qcow2', 5 * units.Mi,
options={'data_file': data_fn,
'data_file_raw': 'on'})
inspector = format_inspector.QcowInspector.from_file(fn)
self.assertRaisesRegex(format_inspector.SafetyCheckFailed,
'.*data_file.*',
inspector.safety_check)
# Trying to load a non-QCOW file is an error
self.assertRaises(format_inspector.ImageFormatError,
format_inspector.QcowInspector.from_file,
backing_fn)
def test_qcow2_feature_flag_checks(self):
data = bytearray(512)
data[0:4] = b'QFI\xFB'
inspector = format_inspector.QcowInspector()
inspector.region('header').data = data
def set_version(ver):
data[0x07] = ver
inspector.region_complete('header')
# All zeros, known version, no feature flags - all good
set_version(3)
inspector.check_unknown_features()
# A feature flag set in the first byte (highest-order) is not
# something we know about, so fail.
data[0x48] = 0x01
self.assertRaisesRegex(format_inspector.SafetyViolation,
'Unknown QCOW2 features found',
inspector.check_unknown_features),
# The first bit in the last byte (lowest-order) is known (the dirty
# bit) so that should pass
data[0x48] = 0x00
data[0x4F] = 0x01
inspector.check_unknown_features()
# Currently (as of 2024), the high-order feature flag bit in the low-
# order byte is not assigned, so make sure we reject it.
data[0x4F] = 0x80
self.assertRaisesRegex(format_inspector.SafetyViolation,
'Unknown QCOW2 features found',
inspector.check_unknown_features),
# Version 1 should be rejected outright
set_version(1)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'Unsupported qcow2 version',
inspector.check_unknown_features)
# Version 4 should be rejected outright
set_version(4)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'Unsupported qcow2 version',
inspector.check_unknown_features)
# Version 2 had no feature flagging, so with the above flags still
# set, we should not process that data as feature flags and pass here.
set_version(2)
inspector.check_unknown_features()
def test_qcow2_future_flags(self):
class Qcow2Future(format_inspector.QcowInspector):
"""A hypothetical future where qcow2 has 12 extra features."""
I_FEATURES_MAX_BIT = 12
data = bytearray(512)
data[0:4] = b'QFI\xFB'
inspector = Qcow2Future()
inspector.region('header').data = data
data[0x07] = 3
inspector.region_complete('header')
# Bit 8 is allowed
data[0x4F] = 0x80
inspector.check_unknown_features()
# Bit 9 is allowed
data[0x4E] = 0x01
inspector.check_unknown_features()
# Bit 16 is not allowed
data[0x4E] = 0x81
self.assertRaisesRegex(format_inspector.SafetyViolation,
'Unknown QCOW2 features found',
inspector.check_unknown_features)
def test_vdi(self):
self._test_format('vdi')
def test_invalid_data(self):
wrapper = format_inspector.InspectWrapper(open(__file__, 'rb'))
while True:
chunk = wrapper.read(32)
if not chunk:
break
wrapper.close()
# Make sure this was not detected as any other format
self.assertEqual('raw', str(wrapper.format))
# Make sure that all of the other inspectors do not match and did not
# use too much memory
for fmt in wrapper._inspectors:
if str(fmt) == 'raw':
continue
self.assertFalse(fmt.format_match)
memory = sum(fmt.context_info.values())
self.assertLess(memory, 512 * units.Ki,
'Format used more than 512KiB of memory: %s' % (
fmt.context_info))
def test_invalid_data_without_raw(self):
wrapper = format_inspector.InspectWrapper(
open(__file__, 'rb'),
allowed_formats=['qcow2', 'vmdk'])
while True:
chunk = wrapper.read(32)
if not chunk:
break
wrapper.close()
# Make sure this was not detected as any other format
self.assertRaises(format_inspector.ImageFormatError,
lambda: wrapper.format)
def test_vmdk_invalid_type(self):
fmt = format_inspector.VMDKInspector()
with open(__file__, 'rb') as f:
fmt.eat_chunk(f.read())
fake_rgn = mock.MagicMock()
fake_rgn.complete = True
fake_rgn.data = b'foocreateType="someunknownformat"bar'
with mock.patch.object(fmt, 'has_region', return_value=True):
with mock.patch.object(fmt, 'region', return_value=fake_rgn):
self.assertEqual(0, fmt.virtual_size)
def test_vmdk_with_footer(self):
img_fn = self._create_img('vmdk', 10 * units.Mi,
subformat='streamOptimized')
# Make the file signal that there is a footer, add a footer, but with
# invalid data
with open(img_fn, 'rb+') as f:
# Write the "expect a footer" sentinel into the header
f.seek(56)
f.write(
struct.pack('<Q', format_inspector.VMDKInspector.GD_AT_END))
# Add room for the footer marker, footer, and EOS marker, but
# filled with zeroes (which is invalid)
f.seek(0, 2)
f.write(b'\x00' * 512 * 3)
fmt = format_inspector.VMDKInspector.from_file(img_fn)
self.assertRaisesRegex(format_inspector.SafetyCheckFailed,
'footer',
fmt.safety_check)
# Make the footer and footer/EOS markers legit
header = bytearray(fmt.region('header').data)
# This is gdOffset, which must not be GD_AT_END in the footer
header[56:57] = b'\x00'
with open(img_fn, 'rb+') as f:
# This is the footer marker (type=3)
f.seek(-512 * 3 + 12, 2)
f.write(b'\x03\x00\x00\x00')
# Second-to-last sector is the footer, which must be a copy of the
# header but with gdOffset set to something other than the flag.
f.seek(-512 * 2, 2)
f.write(header)
# With everything set to legit values, we should pass the check now
fmt = format_inspector.VMDKInspector.from_file(img_fn)
fmt.safety_check()
# Make sure we properly detect this type of VMDK
det = format_inspector.detect_file_format(img_fn)
self.assertEqual(format_inspector.VMDKInspector, det.__class__)
def test_vmdk_footer_checks(self):
def make_header(sig=b'KDMV', ver=1, d_sec=1, d_off=0x200, gdo=None):
return struct.pack('<4sIIQQQQIQQ', sig, ver, 0, 0, 0, d_sec, d_off,
0, 0,
gdo or format_inspector.VMDKInspector.GD_AT_END)
def make_footer(fm_typ=3, fm_sz=0, fm_pad=b'\x00',
eos_typ=0, eos_sz=0, eos_pad=b'\x00',
**header):
region = bytearray(b'\x00' * 512 * 3)
region[512:1024] = make_header(**header)
region[8] = fm_sz
region[12] = fm_typ
region[16:512] = fm_pad * 496
region[1024 + 8] = eos_sz
region[1024 + 12] = eos_typ
region[1024 + 16:] = eos_pad * 496
return region
fmt = format_inspector.VMDKInspector()
fmt.new_region('footer', format_inspector.EndCaptureRegion(512 * 3))
fmt.region('header').data = make_header()
# Signature must match header
fmt.region('footer').data = make_footer(sig=b'leak')
self.assertRaisesRegex(format_inspector.SafetyViolation,
'signature', fmt.check_footer)
# Version must match header
fmt.region('footer').data = make_footer(ver=2)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'version', fmt.check_footer)
# Descriptor cannot be longer
fmt.region('footer').data = make_footer(d_sec=2)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'descriptor', fmt.check_footer)
# Descriptor cannot be relocated
fmt.region('footer').data = make_footer(d_off=0x300)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'descriptor', fmt.check_footer)
# Footer must not have GD_AT_END implying another footer
fmt.region('footer').data = make_footer()
self.assertRaisesRegex(format_inspector.SafetyViolation,
'another footer', fmt.check_footer)
# Footer marker type must be correct
fmt.region('footer').data = make_footer(gdo=123, fm_typ=7)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'marker', fmt.check_footer)
# Footer marker must indicate size=0
fmt.region('footer').data = make_footer(gdo=123, fm_sz=1)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'marker', fmt.check_footer)
# Footer marker must be zero-padded
fmt.region('footer').data = make_footer(gdo=123, fm_pad=b'\x01')
self.assertRaisesRegex(format_inspector.SafetyViolation,
'marker', fmt.check_footer)
# EOS marker type must be correct
fmt.region('footer').data = make_footer(gdo=123, eos_typ=7)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'marker', fmt.check_footer)
# EOS marker must indicate size=0
fmt.region('footer').data = make_footer(gdo=123, eos_sz=1)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'marker', fmt.check_footer)
# EOS marker must be zero-padded
fmt.region('footer').data = make_footer(gdo=123, eos_pad=b'\x01')
self.assertRaisesRegex(format_inspector.SafetyViolation,
'marker', fmt.check_footer)
# Everything in place should pass
fmt.region('footer').data = make_footer(gdo=123)
fmt.check_footer()
def test_vmdk_safety_checks(self):
descriptor_lines = [
'# a comment',
'createType monolithicFlat',
'',
' ',
'someUnknownThing=foo',
'ddb whatever',
'rw 0 somefile.vmdk',
]
def setup_check():
fmt = format_inspector.VMDKInspector()
fmt.region('header').data = b'KDMV' * 128
data = ('\n'.join(descriptor_lines)).encode()
data += b'\x00' * (512 - len(data))
fmt.region('descriptor').data = data
fmt.region_complete('descriptor')
return fmt
# This should fail because the createType header is broken
fmt = setup_check()
e = self.assertRaises(format_inspector.SafetyCheckFailed,
fmt.safety_check)
self.assertIn('Unsupported subformat', str(e.failures['descriptor']))
# This should fail because the createType is not safe
descriptor_lines[1] = 'createType="monolithicFlat"'
e = self.assertRaises(format_inspector.SafetyCheckFailed,
fmt.safety_check)
self.assertIn('Unsupported subformat', str(e.failures['descriptor']))
# Fix createType and make sure we pass now
descriptor_lines[1] = 'createType="monolithicSparse"'
fmt = setup_check()
fmt.safety_check()
# Add an extent in an invalid mode which we will not recognize and fail
descriptor_lines.append('wronly 2048 somefile2.vmdk')
fmt = setup_check()
e = self.assertRaises(format_inspector.SafetyCheckFailed,
fmt.safety_check)
self.assertIn('descriptor data', str(e.failures['descriptor']))
# Add an extent with a valid mode but an invalid character
descriptor_lines[-1] = 'rw 2048 /etc/hosts'
fmt = setup_check()
e = self.assertRaises(format_inspector.SafetyCheckFailed,
fmt.safety_check)
self.assertIn('extent filenames', str(e.failures['descriptor']))
# Make sure we fail if there are no extents
descriptor_lines.pop()
descriptor_lines.pop()
fmt = setup_check()
e = self.assertRaises(format_inspector.SafetyCheckFailed,
fmt.safety_check)
self.assertIn('No extents found', str(e.failures['descriptor']))
def test_vmdk_format_checks(self):
# Invalid signature
fmt = format_inspector.VMDKInspector()
chunk = (b'\x00' * 512)
self.assertRaisesRegex(format_inspector.ImageFormatError,
'Signature',
fmt.eat_chunk, chunk)
# Good signature but unknown version
fmt = format_inspector.VMDKInspector()
chunk = b'KDMV\x00' + (b'\x00' * 512)
self.assertRaisesRegex(format_inspector.ImageFormatError,
'Unsupported format version',
fmt.eat_chunk, chunk)
# Good signature and version, no footer, invalid descriptor location
fmt = format_inspector.VMDKInspector()
chunk = bytearray(b'\x00' * 512)
chunk[0:5] = b'KDMV\x01'
self.assertRaisesRegex(format_inspector.ImageFormatError,
'Wrong descriptor location',
fmt.eat_chunk, chunk)
def test_gpt_mbr_check(self):
data = bytearray(b'\x00' * 512 * 2)
data[510:512] = b'\x55\xAA'
fmt = format_inspector.GPTInspector()
def mkpte(n=0, boot=0, ostype=0xEE, starth=2, startlba=1):
data[446 + n * 16:446 + n * 16 + 16] = struct.pack(
'<BBBBBBBBII',
boot, # boot
0x00, # start C
starth, # start H
0x00, # start S
ostype, # OS type
0x00, # end C
0x00, # end H
0x00, # end S
startlba, # start LBA
0x00, # size LBA
)
fmt.region('mbr').data = data
fmt.region_complete('mbr')
# Make sure we pass with EFI partition and correct values
mkpte()
fmt.check_mbr_partitions()
# Make sure we fail if the boot flag is not one of the valid values
mkpte(boot=0xA)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'invalid boot flag',
fmt.check_mbr_partitions)
# Make sure we fail if no partitions are defined. This is probably
# not a safety problem, but may mean that we mis-identified the image.
mkpte(ostype=0)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'no partitions defined',
fmt.check_mbr_partitions)
# EFI Protective MBRs are not allowed to have any other partitions
# defined other than the GPT-protecting one.
mkpte()
mkpte(n=1)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'invalid extra partitions',
fmt.check_mbr_partitions)
# Make sure that we tolerate any start CHS value for non-EFI types,
# but refuse outside the required values for EFI.
mkpte(n=1, ostype=2)
mkpte(ostype=0x8E, starth=1)
fmt.check_mbr_partitions()
mkpte(starth=1)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'invalid start CHS',
fmt.check_mbr_partitions)
# Make sure that we tolerate any start LBA value for non-EFI types,
# but refuse outside the required values for EFI.
mkpte(ostype=0x8E, startlba=2)
fmt.check_mbr_partitions()
mkpte(startlba=2)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'invalid start LBA',
fmt.check_mbr_partitions)
def test_unique_names(self):
for key, inspector_cls in format_inspector.ALL_FORMATS.items():
self.assertEqual(key, inspector_cls.NAME)
class TestFormatInspectorInfra(test_base.BaseTestCase):
def _test_capture_region_bs(self, bs):
data = b''.join(chr(x).encode() for x in range(ord('A'), ord('z')))
regions = [
format_inspector.CaptureRegion(3, 9),
format_inspector.CaptureRegion(0, 256),
format_inspector.CaptureRegion(32, 8),
format_inspector.EndCaptureRegion(32),
format_inspector.EndCaptureRegion(5),
]
for region in regions:
# None of them should be complete yet
self.assertFalse(region.complete)
pos = 0
for i in range(0, len(data), bs):
chunk = data[i:i + bs]
pos += len(chunk)
for region in regions:
region.capture(chunk, pos)
# The end regions should not be complete until we signal EOF
self.assertFalse(regions[3].complete)
self.assertFalse(regions[4].complete)
for region in regions:
try:
region.finish()
except AttributeError:
pass
self.assertEqual(data[3:12], regions[0].data)
self.assertEqual(data[0:256], regions[1].data)
self.assertEqual(data[32:40], regions[2].data)
self.assertEqual(data[-32:], regions[3].data)
self.assertEqual(data[-5:], regions[4].data)
# The small regions should be complete
self.assertTrue(regions[0].complete)
self.assertTrue(regions[2].complete)
# The end regions should be complete
self.assertTrue(regions[3].complete)
self.assertTrue(regions[4].complete)
# This region extended past the available data, so not complete
self.assertFalse(regions[1].complete)
def test_capture_region(self):
for block_size in (1, 3, 7, 13, 32, 64):
self._test_capture_region_bs(block_size)
def _get_wrapper(self, data):
source = io.BytesIO(data)
return format_inspector.InspectWrapper(source)
def test_info_wrapper_file_like(self):
data = b''.join(chr(x).encode() for x in range(ord('A'), ord('z')))
wrapper = self._get_wrapper(data)
read_data = b''
while True:
chunk = wrapper.read(8)
if not chunk:
break
read_data += chunk
self.assertEqual(data, read_data)
def test_info_wrapper_iter_like(self):
data = b''.join(chr(x).encode() for x in range(ord('A'), ord('z')))
wrapper = self._get_wrapper(data)
read_data = b''
for chunk in wrapper:
read_data += chunk
self.assertEqual(data, read_data)
@mock.patch.object(format_inspector.VMDKInspector, 'eat_chunk')
def test_info_wrapper_file_like_eats_error(self, mock_eat):
wrapper = self._get_wrapper(b'123456')
mock_eat.side_effect = Exception('fail')
data = b''
while True:
chunk = wrapper.read(3)
if not chunk:
break
data += chunk
# Make sure we got all the data despite the error
self.assertEqual(b'123456', data)
# Make sure we only called this once and never again after
# the error was raised
mock_eat.assert_called_once_with(b'123')
@mock.patch.object(format_inspector.VMDKInspector, 'eat_chunk')
@mock.patch.object(format_inspector.LOG, 'debug')
def test_wrapper_iter_like_eats_error(self, mock_log, mock_eat,
expected=None):
wrapper = format_inspector.InspectWrapper(iter([b'123', b'456']),
expected_format=expected)
mock_eat.side_effect = Exception('fail')
data = b''
for chunk in wrapper:
data += chunk
# Make sure we got all the data despite the error
self.assertEqual(b'123456', data)
# Make sure we only called this once and never again after
# the error was raised
mock_eat.assert_called_once_with(b'123')
if expected:
self.assertFalse(mock_log.called)
else:
self.assertTrue(mock_log.called)
def test_wrapper_iter_like_eats_error_expected_quiet(self):
# Test with an expected format, but not the one we're going to
# intentionally fail to make sure that we do not log failures
# for non-expected formats.
self.test_wrapper_iter_like_eats_error(expected='vhd')
def test_get_inspector(self):
self.assertEqual(format_inspector.QcowInspector,
format_inspector.get_inspector('qcow2'))
self.assertIsNone(format_inspector.get_inspector('foo'))
def test_safety_check_records_result(self):
def fake_check():
raise format_inspector.SafetyViolation('myresult')
check = format_inspector.SafetyCheck('foo', fake_check,
description='a fake check')
self.assertRaisesRegex(format_inspector.SafetyViolation,
'myresult',
check)
def test_safety_check_records_failure(self):
# This check will fail with ValueError
check = format_inspector.SafetyCheck('foo', lambda: int('a'),
description='a fake check')
self.assertRaisesRegex(format_inspector.SafetyViolation,
'Unexpected error',
check)
def test_safety_check_constants(self):
null_check = format_inspector.SafetyCheck.null()
self.assertIsInstance(null_check, format_inspector.SafetyCheck)
self.assertIsNone(null_check())
banned_check = format_inspector.SafetyCheck.banned()
self.assertIsInstance(banned_check, format_inspector.SafetyCheck)
self.assertRaisesRegex(format_inspector.SafetyViolation,
'not allowed',
banned_check)
def test_safety_check_error_conditions(self):
inspector = format_inspector.QcowInspector()
self.assertRaisesRegex(format_inspector.ImageFormatError,
'Incomplete file.*',
inspector.safety_check)
inspector.eat_chunk(b'\x00' * 512)
self.assertRaisesRegex(format_inspector.ImageFormatError,
'content does not match',
inspector.safety_check)
self.assertRaises(RuntimeError, inspector.add_safety_check, 'foo')
def test_safety_checks_required(self):
class BadSafetyCheck(format_inspector.FileInspector):
def _initialize(self):
# No safety checks!
return
@property
def format_match(self):
return True
self.assertRaisesRegex(RuntimeError, 'at least one safety',
BadSafetyCheck)
def test_finish_is_final(self):
fmt = format_inspector.RawFileInspector()
fmt.eat_chunk(b'\x00')
fmt.finish()
self.assertRaises(RuntimeError, fmt.eat_chunk, b'\x00')
class TestFormatInspectorsTargeted(test_base.BaseTestCase):
def _make_vhd_meta(self, guid_raw, item_length):
# Meta region header, padded to 32 bytes
data = struct.pack('<8sHH', b'metadata', 0, 1)
data += b'0' * 20
# Metadata table entry, 16-byte GUID, 12-byte information,
# padded to 32-bytes
data += guid_raw
data += struct.pack('<III', 256, item_length, 0)
data += b'0' * 6
return data
def test_vhd_table_over_limit(self):
ins = format_inspector.VHDXInspector()
meta = format_inspector.CaptureRegion(0, 0)
desired = b'012345678ABCDEF0'
# This is a poorly-crafted image that specifies a larger table size
# than is allowed
meta.data = self._make_vhd_meta(desired, 33 * 2048)
ins.new_region('metadata', meta)
new_region = ins._find_meta_entry(ins._guid(desired))
# Make sure we clamp to our limit of 32 * 2048
self.assertEqual(
format_inspector.VHDXInspector.VHDX_METADATA_TABLE_MAX_SIZE,
new_region.length)
def test_vhd_table_under_limit(self):
ins = format_inspector.VHDXInspector()
meta = format_inspector.CaptureRegion(0, 0)
desired = b'012345678ABCDEF0'
meta.data = self._make_vhd_meta(desired, 16 * 2048)
ins.new_region('metadata', meta)
new_region = ins._find_meta_entry(ins._guid(desired))
# Table size was under the limit, make sure we get it back
self.assertEqual(16 * 2048, new_region.length)