block: an interoperability test for luks vs dm-crypt/cryptsetup

It is important that the QEMU luks implementation retains 100%
compatibility with the reference implementation provided by
the combination of the linux kernel dm-crypt module and cryptsetup
userspace tools.

There is a matrix of tests to be performed with different sets
of encryption settings. For each matrix entry, two tests will
be performed. One will create a LUKS image with the cryptsetup
tool and then do I/O with both cryptsetup & qemu-io. The other
will create the image with qemu-img and then again do I/O with
both cryptsetup and qemu-io.

The new I/O test 149 performs interoperability testing between
QEMU and the reference implementation. Such testing inherantly
requires elevated privileges, so to this this the user must have
configured passwordless sudo access. The test will automatically
skip if sudo is not available.

The test has to be run explicitly thus:

    cd tests/qemu-iotests
    ./check -luks 149

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 519 insertions, 0 deletions

diff --git a/tests/qemu-iotests/149 b/tests/qemu-iotests/149
new file mode 100755
index 0000000000..bb5811d93b
--- /dev/null
+++ b/tests/qemu-iotests/149
@@ -0,0 +1,519 @@
+#!/usr/bin/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
+    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",
+               }),
+]
+
+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)