placement/nova/volume/encryptors/cryptsetup.py
Kaitlin Farr c7ccad4a02 Replace key manager with Castellan
Because key manager code is duplicated across several projects, a key
manager interface was moved into its own library. This patch goes back
to replace the old code with the new library.

Change-Id: Ib563b0ea4b8b4bc1833bf52bf49a68546c384996
Implements: blueprint use-castellan-key-manager
2016-04-27 14:37:06 -04:00

117 lines
4.5 KiB
Python

# Copyright (c) 2013 The Johns Hopkins University/Applied Physics Laboratory
# 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 binascii
import os
from oslo_log import log as logging
from nova import exception
from nova import utils
from nova.volume.encryptors import base
LOG = logging.getLogger(__name__)
class CryptsetupEncryptor(base.VolumeEncryptor):
"""A VolumeEncryptor based on dm-crypt.
This VolumeEncryptor uses dm-crypt to encrypt the specified volume.
"""
def __init__(self, connection_info, **kwargs):
super(CryptsetupEncryptor, self).__init__(connection_info, **kwargs)
# Fail if no device_path was set when connecting the volume, e.g. in
# the case of libvirt network volume drivers.
data = connection_info['data']
if not data.get('device_path'):
volume_id = data.get('volume_id') or connection_info.get('serial')
raise exception.VolumeEncryptionNotSupported(
volume_id=volume_id,
volume_type=connection_info['driver_volume_type'])
# the device's path as given to libvirt -- e.g., /dev/disk/by-path/...
self.symlink_path = connection_info['data']['device_path']
# a unique name for the volume -- e.g., the iSCSI participant name
self.dev_name = self.symlink_path.split('/')[-1]
# the device's actual path on the compute host -- e.g., /dev/sd_
self.dev_path = os.path.realpath(self.symlink_path)
def _get_passphrase(self, key):
"""Convert raw key to string."""
return binascii.hexlify(key).decode('utf-8')
def _open_volume(self, passphrase, **kwargs):
"""Opens the LUKS partition on the volume using the specified
passphrase.
:param passphrase: the passphrase used to access the volume
"""
LOG.debug("opening encrypted volume %s", self.dev_path)
# NOTE(joel-coffman): cryptsetup will strip trailing newlines from
# input specified on stdin unless --key-file=- is specified.
cmd = ["cryptsetup", "create", "--key-file=-"]
cipher = kwargs.get("cipher", None)
if cipher is not None:
cmd.extend(["--cipher", cipher])
key_size = kwargs.get("key_size", None)
if key_size is not None:
cmd.extend(["--key-size", key_size])
cmd.extend([self.dev_name, self.dev_path])
utils.execute(*cmd, process_input=passphrase,
check_exit_code=True, run_as_root=True)
def attach_volume(self, context, **kwargs):
"""Shadows the device and passes an unencrypted version to the
instance.
Transparent disk encryption is achieved by mounting the volume via
dm-crypt and passing the resulting device to the instance. The
instance is unaware of the underlying encryption due to modifying the
original symbolic link to refer to the device mounted by dm-crypt.
"""
key = self._get_key(context).get_encoded()
passphrase = self._get_passphrase(key)
self._open_volume(passphrase, **kwargs)
# modify the original symbolic link to refer to the decrypted device
utils.execute('ln', '--symbolic', '--force',
'/dev/mapper/%s' % self.dev_name, self.symlink_path,
run_as_root=True, check_exit_code=True)
def _close_volume(self, **kwargs):
"""Closes the device (effectively removes the dm-crypt mapping)."""
LOG.debug("closing encrypted volume %s", self.dev_path)
# cryptsetup returns 4 when attempting to destroy a non-active
# dm-crypt device. We are going to ignore this error code to make
# nova deleting that instance successfully.
utils.execute('cryptsetup', 'remove', self.dev_name,
run_as_root=True, check_exit_code=[0, 4])
def detach_volume(self, **kwargs):
"""Removes the dm-crypt mapping for the device."""
self._close_volume(**kwargs)