117 lines
4.5 KiB
Python
117 lines
4.5 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 binascii
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import os
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from oslo_log import log as logging
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from nova import exception
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from nova import utils
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from nova.volume.encryptors import base
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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, connection_info, **kwargs):
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super(CryptsetupEncryptor, self).__init__(connection_info, **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 = self.symlink_path.split('/')[-1]
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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 _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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"""Opens the LUKS partition on the volume using the specified
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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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utils.execute(*cmd, process_input=passphrase,
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check_exit_code=True, run_as_root=True)
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def attach_volume(self, context, **kwargs):
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"""Shadows the device and passes an unencrypted version to the
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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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key = self._get_key(context).get_encoded()
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passphrase = self._get_passphrase(key)
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self._open_volume(passphrase, **kwargs)
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# modify the original symbolic link to refer to the decrypted device
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utils.execute('ln', '--symbolic', '--force',
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'/dev/mapper/%s' % self.dev_name, self.symlink_path,
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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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# cryptsetup returns 4 when attempting to destroy a non-active
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# dm-crypt device. We are going to ignore this error code to make
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# nova deleting that instance successfully.
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utils.execute('cryptsetup', 'remove', self.dev_name,
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run_as_root=True, check_exit_code=[0, 4])
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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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