#!/usr/bin/env python3
# group: rw sudo
#
# 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.encode('ascii')).decode('ascii')

    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,
                            universal_newlines=True)

    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,
                            universal_newlines=True)

    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", "-",
                "--iter-time", "10",
                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", "--type", "luks1"]
    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.extend(["--iter-time", "10"])
    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(msg)


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 check_cipher_support(config, output):
    """Check the output of qemu-img or qemu-io for mention of the respective
    cipher algorithm being unsupported, and if so, skip this test.
    (Returns `output` for convenience.)"""

    if 'Unsupported cipher algorithm' in output:
        iotests.notrun('Unsupported cipher algorithm '
                       f'{config.cipher}-{config.keylen}-{config.mode}; '
                       'consider configuring qemu with a different crypto '
                       'backend')
    return output

def qemu_img_create(config, size_mb):
    """Create and format a disk image with LUKS using qemu-img"""

    opts = [
        "key-secret=sec0",
        "iter-time=10",
        "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])
    try:
        iotests.qemu_img(*args)
    except subprocess.CalledProcessError as exc:
        check_cipher_support(config, exc.output)
        raise

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=host_device,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"""

    if dev:
        chown(config)
    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])
    output = iotests.qemu_io(*args, check=False).stdout
    iotests.log(check_cipher_support(config, output),
                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"""

    if dev:
        chown(config)
    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])
    output = iotests.qemu_io(*args, check=False).stdout
    iotests.log(check_cipher_support(config, output),
                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("# 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("# 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.script_initialize(supported_fmts=['luks'])

# 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-sha224",
               "aes", 256, "xts", "plain64", None, "sha224"),
    LUKSConfig("aes-256-xts-plain64-sha256",
               "aes", 256, "xts", "plain64", None, "sha256"),
    LUKSConfig("aes-256-xts-plain64-sha384",
               "aes", 256, "xts", "plain64", None, "sha384"),
    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",
]

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)