b3e5aa3761
This encryptor and the underlying plain cryptsetup encryption format it provides is not widely used, inflexible (no key rotation) and as a result no longer required in os-brick. This change starts the deprecation process. Additional changes will be posted to ensure the retype workflow between this encryptor and the LUKS based encryptors is well tested ahead of any removal. Change-Id: Ibb560da269a2f330526af6761fa509c262e3d361
194 lines
8.4 KiB
Python
194 lines
8.4 KiB
Python
# Copyright (c) 2013 The Johns Hopkins University/Applied Physics Laboratory
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import array
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import binascii
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import os
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from os_brick.encryptors import base
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from os_brick import exception
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from oslo_concurrency import processutils
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from oslo_log import log as logging
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from oslo_log import versionutils
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LOG = logging.getLogger(__name__)
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class CryptsetupEncryptor(base.VolumeEncryptor):
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"""A VolumeEncryptor based on dm-crypt.
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This VolumeEncryptor uses dm-crypt to encrypt the specified volume.
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"""
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def __init__(self, root_helper,
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connection_info,
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keymgr,
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execute=None,
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*args, **kwargs):
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super(CryptsetupEncryptor, self).__init__(
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root_helper=root_helper,
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connection_info=connection_info,
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keymgr=keymgr,
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execute=execute,
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*args, **kwargs)
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# Fail if no device_path was set when connecting the volume, e.g. in
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# the case of libvirt network volume drivers.
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data = connection_info['data']
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if not data.get('device_path'):
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volume_id = data.get('volume_id') or connection_info.get('serial')
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raise exception.VolumeEncryptionNotSupported(
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volume_id=volume_id,
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volume_type=connection_info['driver_volume_type'])
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# the device's path as given to libvirt -- e.g., /dev/disk/by-path/...
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self.symlink_path = connection_info['data']['device_path']
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# a unique name for the volume -- e.g., the iSCSI participant name
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self.dev_name = 'crypt-%s' % os.path.basename(self.symlink_path)
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# NOTE(lixiaoy1): This is to import fix for 1439869 from Nova.
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# NOTE(tsekiyama): In older version of nova, dev_name was the same
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# as the symlink name. Now it has 'crypt-' prefix to avoid conflict
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# with multipath device symlink. To enable rolling update, we use the
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# old name when the encrypted volume already exists.
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old_dev_name = os.path.basename(self.symlink_path)
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wwn = data.get('multipath_id')
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if self._is_crypt_device_available(old_dev_name):
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self.dev_name = old_dev_name
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LOG.debug("Using old encrypted volume name: %s", self.dev_name)
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elif wwn and wwn != old_dev_name:
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# FibreChannel device could be named '/dev/mapper/<WWN>'.
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if self._is_crypt_device_available(wwn):
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self.dev_name = wwn
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LOG.debug("Using encrypted volume name from wwn: %s",
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self.dev_name)
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# the device's actual path on the compute host -- e.g., /dev/sd_
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self.dev_path = os.path.realpath(self.symlink_path)
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def _is_crypt_device_available(self, dev_name):
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if not os.path.exists('/dev/mapper/%s' % dev_name):
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return False
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try:
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self._execute('cryptsetup', 'status', dev_name, run_as_root=True)
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except processutils.ProcessExecutionError as e:
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# If /dev/mapper/<dev_name> is a non-crypt block device (such as a
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# normal disk or multipath device), exit_code will be 1. In the
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# case, we will omit the warning message.
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if e.exit_code != 1:
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LOG.warning('cryptsetup status %(dev_name)s exited '
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'abnormally (status %(exit_code)s): %(err)s',
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{"dev_name": dev_name, "exit_code": e.exit_code,
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"err": e.stderr})
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return False
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return True
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def _get_passphrase(self, key):
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"""Convert raw key to string."""
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return binascii.hexlify(key).decode('utf-8')
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def _open_volume(self, passphrase, **kwargs):
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"""Open the LUKS partition on the volume using passphrase.
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:param passphrase: the passphrase used to access the volume
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"""
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LOG.debug("opening encrypted volume %s", self.dev_path)
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# NOTE(joel-coffman): cryptsetup will strip trailing newlines from
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# input specified on stdin unless --key-file=- is specified.
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cmd = ["cryptsetup", "create", "--key-file=-"]
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cipher = kwargs.get("cipher", None)
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if cipher is not None:
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cmd.extend(["--cipher", cipher])
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key_size = kwargs.get("key_size", None)
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if key_size is not None:
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cmd.extend(["--key-size", key_size])
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cmd.extend([self.dev_name, self.dev_path])
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self._execute(*cmd, process_input=passphrase,
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check_exit_code=True, run_as_root=True,
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root_helper=self._root_helper)
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def _get_mangled_passphrase(self, key):
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"""Convert the raw key into a list of unsigned int's and then a string
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"""
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# NOTE(lyarwood): This replicates the methods used prior to Newton to
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# first encode the passphrase as a list of unsigned int's before
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# decoding back into a string. This method strips any leading 0's
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# of the resulting hex digit pairs, resulting in a different
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# passphrase being returned.
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encoded_key = array.array('B', key).tolist()
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return ''.join(hex(x).replace('0x', '') for x in encoded_key)
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def attach_volume(self, context, **kwargs):
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"""Shadow the device and pass an unencrypted version to the instance.
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Transparent disk encryption is achieved by mounting the volume via
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dm-crypt and passing the resulting device to the instance. The
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instance is unaware of the underlying encryption due to modifying the
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original symbolic link to refer to the device mounted by dm-crypt.
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"""
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# TODO(lyarwood): Remove this encryptor and refactor the LUKS based
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# encryptors in the U release.
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versionutils.report_deprecated_feature(
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LOG,
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"The plain CryptsetupEncryptor is deprecated and will be removed "
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"in a future release. Existing users are encouraged to retype "
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"any existing volumes using this encryptor to the 'luks' "
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"LuksEncryptor or 'luks2' Luks2Encryptor encryptors as soon as "
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"possible.")
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key = self._get_key(context).get_encoded()
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passphrase = self._get_passphrase(key)
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try:
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self._open_volume(passphrase, **kwargs)
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except processutils.ProcessExecutionError as e:
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if e.exit_code == 2:
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# NOTE(lyarwood): Workaround bug#1633518 by attempting to use
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# a mangled passphrase to open the device..
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LOG.info("Unable to open %s with the current passphrase, "
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"attempting to use a mangled passphrase to open "
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"the volume.", self.dev_path)
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self._open_volume(self._get_mangled_passphrase(key), **kwargs)
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# modify the original symbolic link to refer to the decrypted device
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self._execute('ln', '--symbolic', '--force',
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'/dev/mapper/%s' % self.dev_name, self.symlink_path,
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root_helper=self._root_helper,
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run_as_root=True, check_exit_code=True)
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def _close_volume(self, **kwargs):
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"""Closes the device (effectively removes the dm-crypt mapping)."""
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LOG.debug("closing encrypted volume %s", self.dev_path)
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# NOTE(mdbooth): remove will return 4 (wrong device specified) if
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# the device doesn't exist. We assume here that the caller hasn't
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# specified the wrong device, and that it doesn't exist because it
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# isn't open. We don't fail in this case in order to make this
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# operation idempotent.
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self._execute('cryptsetup', 'remove', self.dev_name,
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run_as_root=True, check_exit_code=[0, 4],
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root_helper=self._root_helper)
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def detach_volume(self, **kwargs):
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"""Removes the dm-crypt mapping for the device."""
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self._close_volume(**kwargs)
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