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qemu/tests/qemu-iotests/149
Daniel P. Berrange 8b7cdba386 crypto: fix handling of iv generator hash defaults 
When opening an existing LUKS volume, if the iv generator is
essiv, then the iv hash algorithm is mandatory to provide. We
must report an error if it is omitted in the cipher mode spec,
not silently default to hash 0 (md5).  If the iv generator is
not essiv, then we explicitly ignore any iv hash algorithm,
rather than report an error, for compatibility with dm-crypt.

When creating a new LUKS volume, if the iv generator is essiv
and no iv hsah algorithm is provided, we should default to
using the sha256 hash.

Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-07-04 10:46:59 +01:00

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#!/usr/bin/env python
#
# Copyright (C) 2016 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: Daniel P. Berrange <berrange@redhat.com>
#
# Exercise the QEMU 'luks' block driver to validate interoperability
# with the Linux dm-crypt + cryptsetup implementation
import subprocess
import os
import os.path
import base64
import iotests
class LUKSConfig(object):
"""Represent configuration parameters for a single LUKS
setup to be tested"""
def __init__(self, name, cipher, keylen, mode, ivgen,
ivgen_hash, hash, password=None, passwords=None):
self.name = name
self.cipher = cipher
self.keylen = keylen
self.mode = mode
self.ivgen = ivgen
self.ivgen_hash = ivgen_hash
self.hash = hash
if passwords is not None:
self.passwords = passwords
else:
self.passwords = {}
if password is None:
self.passwords["0"] = "123456"
else:
self.passwords["0"] = password
def __repr__(self):
return self.name
def image_name(self):
return "luks-%s.img" % self.name
def image_path(self):
return os.path.join(iotests.test_dir, self.image_name())
def device_name(self):
return "qiotest-145-%s" % self.name
def device_path(self):
return "/dev/mapper/" + self.device_name()
def first_password(self):
for i in range(8):
slot = str(i)
if slot in self.passwords:
return (self.passwords[slot], slot)
raise Exception("No password found")
def first_password_base64(self):
(pw, slot) = self.first_password()
return base64.b64encode(pw)
def active_slots(self):
slots = []
for i in range(8):
slot = str(i)
if slot in self.passwords:
slots.append(slot)
return slots
def verify_passwordless_sudo():
"""Check whether sudo is configured to allow
password-less access to commands"""
args = ["sudo", "-n", "/bin/true"]
proc = subprocess.Popen(args,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT)
msg = proc.communicate()[0]
if proc.returncode != 0:
iotests.notrun('requires password-less sudo access: %s' % msg)
def cryptsetup(args, password=None):
"""Run the cryptsetup command in batch mode"""
fullargs = ["sudo", "cryptsetup", "-q", "-v"]
fullargs.extend(args)
iotests.log(" ".join(fullargs), filters=[iotests.filter_test_dir])
proc = subprocess.Popen(fullargs,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT)
msg = proc.communicate(password)[0]
if proc.returncode != 0:
raise Exception(msg)
def cryptsetup_add_password(config, slot):
"""Add another password to a LUKS key slot"""
(password, mainslot) = config.first_password()
pwfile = os.path.join(iotests.test_dir, "passwd.txt")
with open(pwfile, "w") as fh:
fh.write(config.passwords[slot])
try:
args = ["luksAddKey", config.image_path(),
"--key-slot", slot,
"--key-file", "-",
pwfile]
cryptsetup(args, password)
finally:
os.unlink(pwfile)
def cryptsetup_format(config):
"""Format a new LUKS volume with cryptsetup, adding the
first key slot only"""
(password, slot) = config.first_password()
args = ["luksFormat"]
cipher = config.cipher + "-" + config.mode + "-" + config.ivgen
if config.ivgen_hash is not None:
cipher = cipher + ":" + config.ivgen_hash
elif config.ivgen == "essiv":
cipher = cipher + ":" + "sha256"
args.extend(["--cipher", cipher])
if config.mode == "xts":
args.extend(["--key-size", str(config.keylen * 2)])
else:
args.extend(["--key-size", str(config.keylen)])
if config.hash is not None:
args.extend(["--hash", config.hash])
args.extend(["--key-slot", slot])
args.extend(["--key-file", "-"])
args.append(config.image_path())
cryptsetup(args, password)
def chown(config):
"""Set the ownership of a open LUKS device to this user"""
path = config.device_path()
args = ["sudo", "chown", "%d:%d" % (os.getuid(), os.getgid()), path]
iotests.log(" ".join(args), filters=[iotests.filter_chown])
proc = subprocess.Popen(args,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT)
msg = proc.communicate()[0]
if proc.returncode != 0:
raise Exception("Cannot change owner on %s" % path)
def cryptsetup_open(config):
"""Open an image as a LUKS device"""
(password, slot) = config.first_password()
args = ["luksOpen", config.image_path(), config.device_name()]
cryptsetup(args, password)
def cryptsetup_close(config):
"""Close an active LUKS device """
args = ["luksClose", config.device_name()]
cryptsetup(args)
def delete_image(config):
"""Delete a disk image"""
try:
os.unlink(config.image_path())
iotests.log("unlink %s" % config.image_path(),
filters=[iotests.filter_test_dir])
except Exception as e:
pass
def create_image(config, size_mb):
"""Create a bare disk image with requested size"""
delete_image(config)
iotests.log("truncate %s --size %dMB" % (config.image_path(), size_mb),
filters=[iotests.filter_test_dir])
with open(config.image_path(), "w") as fn:
fn.truncate(size_mb * 1024 * 1024)
def qemu_img_create(config, size_mb):
"""Create and format a disk image with LUKS using qemu-img"""
opts = [
"key-secret=sec0",
"cipher-alg=%s-%d" % (config.cipher, config.keylen),
"cipher-mode=%s" % config.mode,
"ivgen-alg=%s" % config.ivgen,
"hash-alg=%s" % config.hash,
]
if config.ivgen_hash is not None:
opts.append("ivgen-hash-alg=%s" % config.ivgen_hash)
args = ["create", "-f", "luks",
"--object",
("secret,id=sec0,data=%s,format=base64" %
config.first_password_base64()),
"-o", ",".join(opts),
config.image_path(),
"%dM" % size_mb]
iotests.log("qemu-img " + " ".join(args), filters=[iotests.filter_test_dir])
iotests.log(iotests.qemu_img_pipe(*args), filters=[iotests.filter_test_dir])
def qemu_io_image_args(config, dev=False):
"""Get the args for access an image or device with qemu-io"""
if dev:
return [
"--image-opts",
"driver=file,filename=%s" % config.device_path()]
else:
return [
"--object",
("secret,id=sec0,data=%s,format=base64" %
config.first_password_base64()),
"--image-opts",
("driver=luks,key-secret=sec0,file.filename=%s" %
config.image_path())]
def qemu_io_write_pattern(config, pattern, offset_mb, size_mb, dev=False):
"""Write a pattern of data to a LUKS image or device"""
args = ["-c", "write -P 0x%x %dM %dM" % (pattern, offset_mb, size_mb)]
args.extend(qemu_io_image_args(config, dev))
iotests.log("qemu-io " + " ".join(args), filters=[iotests.filter_test_dir])
iotests.log(iotests.qemu_io(*args), filters=[iotests.filter_test_dir,
iotests.filter_qemu_io])
def qemu_io_read_pattern(config, pattern, offset_mb, size_mb, dev=False):
"""Read a pattern of data to a LUKS image or device"""
args = ["-c", "read -P 0x%x %dM %dM" % (pattern, offset_mb, size_mb)]
args.extend(qemu_io_image_args(config, dev))
iotests.log("qemu-io " + " ".join(args), filters=[iotests.filter_test_dir])
iotests.log(iotests.qemu_io(*args), filters=[iotests.filter_test_dir,
iotests.filter_qemu_io])
def test_once(config, qemu_img=False):
"""Run the test with a desired LUKS configuration. Can either
use qemu-img for creating the initial volume, or cryptsetup,
in order to test interoperability in both directions"""
iotests.log("# ================= %s %s =================" % (
"qemu-img" if qemu_img else "dm-crypt", config))
oneKB = 1024
oneMB = oneKB * 1024
oneGB = oneMB * 1024
oneTB = oneGB * 1024
# 4 TB, so that we pass the 32-bit sector number boundary.
# Important for testing correctness of some IV generators
# The files are sparse, so not actually using this much space
image_size = 4 * oneTB
if qemu_img:
iotests.log("# Create image")
qemu_img_create(config, image_size / oneMB)
else:
iotests.log("# Create image")
create_image(config, image_size / oneMB)
lowOffsetMB = 100
highOffsetMB = 3 * oneTB / oneMB
try:
if not qemu_img:
iotests.log("# Format image")
cryptsetup_format(config)
for slot in config.active_slots()[1:]:
iotests.log("# Add password slot %s" % slot)
cryptsetup_add_password(config, slot)
# First we'll open the image using cryptsetup and write a
# known pattern of data that we'll then verify with QEMU
iotests.log("# Open dev")
cryptsetup_open(config)
try:
iotests.log("# Set dev owner")
chown(config)
iotests.log("# Write test pattern 0xa7")
qemu_io_write_pattern(config, 0xa7, lowOffsetMB, 10, dev=True)
iotests.log("# Write test pattern 0x13")
qemu_io_write_pattern(config, 0x13, highOffsetMB, 10, dev=True)
finally:
iotests.log("# Close dev")
cryptsetup_close(config)
# Ok, now we're using QEMU to verify the pattern just
# written via dm-crypt
iotests.log("# Read test pattern 0xa7")
qemu_io_read_pattern(config, 0xa7, lowOffsetMB, 10, dev=False)
iotests.log("# Read test pattern 0x13")
qemu_io_read_pattern(config, 0x13, highOffsetMB, 10, dev=False)
# Write a new pattern to the image, which we'll later
# verify with dm-crypt
iotests.log("# Write test pattern 0x91")
qemu_io_write_pattern(config, 0x91, lowOffsetMB, 10, dev=False)
iotests.log("# Write test pattern 0x5e")
qemu_io_write_pattern(config, 0x5e, highOffsetMB, 10, dev=False)
# Now we're opening the image with dm-crypt once more
# and verifying what QEMU wrote, completing the circle
iotests.log("# Open dev")
cryptsetup_open(config)
try:
iotests.log("# Set dev owner")
chown(config)
iotests.log("# Read test pattern 0x91")
qemu_io_read_pattern(config, 0x91, lowOffsetMB, 10, dev=True)
iotests.log("# Read test pattern 0x5e")
qemu_io_read_pattern(config, 0x5e, highOffsetMB, 10, dev=True)
finally:
iotests.log("# Close dev")
cryptsetup_close(config)
finally:
iotests.log("# Delete image")
delete_image(config)
print
# Obviously we only work with the luks image format
iotests.verify_image_format(supported_fmts=['luks'])
iotests.verify_platform()
# We need sudo in order to run cryptsetup to create
# dm-crypt devices. This is safe to use on any
# machine, since all dm-crypt devices are backed
# by newly created plain files, and have a dm-crypt
# name prefix of 'qiotest' to avoid clashing with
# user LUKS volumes
verify_passwordless_sudo()
# If we look at all permutations of cipher, key size,
# mode, ivgen, hash, there are ~1000 possible configs.
#
# We certainly don't want/need to test every permutation
# to get good validation of interoperability between QEMU
# and dm-crypt/cryptsetup.
#
# The configs below are a representative set that aim to
# exercise each axis of configurability.
#
configs = [
# A common LUKS default
LUKSConfig("aes-256-xts-plain64-sha1",
"aes", 256, "xts", "plain64", None, "sha1"),
# LUKS default but diff ciphers
LUKSConfig("twofish-256-xts-plain64-sha1",
"twofish", 256, "xts", "plain64", None, "sha1"),
LUKSConfig("serpent-256-xts-plain64-sha1",
"serpent", 256, "xts", "plain64", None, "sha1"),
# Should really be xts, but kernel doesn't support xts+cast5
# nor does it do essiv+cast5
LUKSConfig("cast5-128-cbc-plain64-sha1",
"cast5", 128, "cbc", "plain64", None, "sha1"),
LUKSConfig("cast6-256-xts-plain64-sha1",
"cast6", 256, "xts", "plain64", None, "sha1"),
# LUKS default but diff modes / ivgens
LUKSConfig("aes-256-cbc-plain-sha1",
"aes", 256, "cbc", "plain", None, "sha1"),
LUKSConfig("aes-256-cbc-plain64-sha1",
"aes", 256, "cbc", "plain64", None, "sha1"),
LUKSConfig("aes-256-cbc-essiv-sha256-sha1",
"aes", 256, "cbc", "essiv", "sha256", "sha1"),
LUKSConfig("aes-256-xts-essiv-sha256-sha1",
"aes", 256, "xts", "essiv", "sha256", "sha1"),
# LUKS default but smaller key sizes
LUKSConfig("aes-128-xts-plain64-sha256-sha1",
"aes", 128, "xts", "plain64", None, "sha1"),
LUKSConfig("aes-192-xts-plain64-sha256-sha1",
"aes", 192, "xts", "plain64", None, "sha1"),
LUKSConfig("twofish-128-xts-plain64-sha1",
"twofish", 128, "xts", "plain64", None, "sha1"),
LUKSConfig("twofish-192-xts-plain64-sha1",
"twofish", 192, "xts", "plain64", None, "sha1"),
LUKSConfig("serpent-128-xts-plain64-sha1",
"serpent", 128, "xts", "plain64", None, "sha1"),
LUKSConfig("serpent-192-xts-plain64-sha1",
"serpent", 192, "xts", "plain64", None, "sha1"),
LUKSConfig("cast6-128-xts-plain64-sha1",
"cast6", 128, "xts", "plain", None, "sha1"),
LUKSConfig("cast6-192-xts-plain64-sha1",
"cast6", 192, "xts", "plain64", None, "sha1"),
# LUKS default but diff hash
LUKSConfig("aes-256-xts-plain64-sha256",
"aes", 256, "xts", "plain64", None, "sha256"),
LUKSConfig("aes-256-xts-plain64-sha512",
"aes", 256, "xts", "plain64", None, "sha512"),
LUKSConfig("aes-256-xts-plain64-ripemd160",
"aes", 256, "xts", "plain64", None, "ripemd160"),
# Password in slot 3
LUKSConfig("aes-256-xts-plain-sha1-pwslot3",
"aes", 256, "xts", "plain", None, "sha1",
passwords={
"3": "slot3",
}),
# Passwords in every slot
LUKSConfig("aes-256-xts-plain-sha1-pwallslots",
"aes", 256, "xts", "plain", None, "sha1",
passwords={
"0": "slot1",
"1": "slot1",
"2": "slot2",
"3": "slot3",
"4": "slot4",
"5": "slot5",
"6": "slot6",
"7": "slot7",
}),
# Check handling of default hash alg (sha256) with essiv
LUKSConfig("aes-256-cbc-essiv-auto-sha1",
"aes", 256, "cbc", "essiv", None, "sha1"),
# Check that a useless hash provided for 'plain64' iv gen
# is ignored and no error raised
LUKSConfig("aes-256-cbc-plain64-sha256-sha1",
"aes", 256, "cbc", "plain64", "sha256", "sha1"),
]
blacklist = [
# We don't have a cast-6 cipher impl for QEMU yet
"cast6-256-xts-plain64-sha1",
"cast6-128-xts-plain64-sha1",
"cast6-192-xts-plain64-sha1",
# GCrypt doesn't support Twofish with 192 bit key
"twofish-192-xts-plain64-sha1",
# We don't have sha512 hash wired up yet
"aes-256-xts-plain64-sha512",
# We don't have ripemd160 hash wired up yet
"aes-256-xts-plain64-ripemd160",
]
whitelist = []
if "LUKS_CONFIG" in os.environ:
whitelist = os.environ["LUKS_CONFIG"].split(",")
for config in configs:
if config.name in blacklist:
iotests.log("Skipping %s in blacklist" % config.name)
continue
if len(whitelist) > 0 and config.name not in whitelist:
iotests.log("Skipping %s not in whitelist" % config.name)
continue
test_once(config, qemu_img=False)
# XXX we should support setting passwords in a non-0
# key slot with 'qemu-img create' in future
(pw, slot) = config.first_password()
if slot == "0":
test_once(config, qemu_img=True)
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