From 5a3ef8b40f85afef2c2e21e22df82603644b3f01 Mon Sep 17 00:00:00 2001 From: Lee Yarwood Date: Fri, 14 Oct 2016 16:41:53 +0100 Subject: [PATCH] encryptors: Workaround mangled passphrases Prior to Ib563b0ea the passphrase used by CryptsetupEncryptor and LuksEncryptor had any leading zeros per hexadecimal digit removed, for example 0x04 or 04 would turn into 0x4 or 4. As a result any volume encrypted prior to the release of Newton used a modified passphrase that was different to that stored by the key manager being used in the environment. To correct this for LuksEncryptor volumes permission denied errors are now caught when attempting to open a volume. A second attempt to open the volume is then made using a mangled passphrase. If successful the correct passphrase is then added to the volume before the mangled passphrase is finally removed. This workaround can be removed in a future release once it is safe to assume that all LuksEncryptor volumes have had any mangled passphrases replaced in this way. This isn't possible for CryptsetupEncryptor volumes as the plain mode used by cryptsetup does not provide a way for adding and removing keys. As such on a permission denied error a second attempt is made to open the volume using a mangled passphrase. Unlike the above workaround this cannot be removed in a future release. Change-Id: I7096463c5eba951dd6322ee6965435e877ca0371 Partial-bug: #1633518 --- .../unit/volume/encryptors/test_cryptsetup.py | 40 ++++++++++++++++--- nova/volume/encryptors/cryptsetup.py | 25 +++++++++++- 2 files changed, 58 insertions(+), 7 deletions(-) diff --git a/nova/tests/unit/volume/encryptors/test_cryptsetup.py b/nova/tests/unit/volume/encryptors/test_cryptsetup.py index e524f40d8..53eb1098c 100644 --- a/nova/tests/unit/volume/encryptors/test_cryptsetup.py +++ b/nova/tests/unit/volume/encryptors/test_cryptsetup.py @@ -19,16 +19,17 @@ import copy from castellan.common.objects import symmetric_key as key import mock +from oslo_concurrency import processutils import six +import uuid from nova import exception from nova.tests.unit.volume.encryptors import test_base from nova.volume.encryptors import cryptsetup -def fake__get_key(context): - raw = bytes(binascii.unhexlify('0' * 32)) - +def fake__get_key(context, passphrase): + raw = bytes(binascii.unhexlify(passphrase)) symmetric_key = key.SymmetricKey('AES', len(raw) * 8, raw) return symmetric_key @@ -59,14 +60,15 @@ class CryptsetupEncryptorTestCase(test_base.VolumeEncryptorTestCase): @mock.patch('nova.utils.execute') def test_attach_volume(self, mock_execute): + fake_key = uuid.uuid4().hex self.encryptor._get_key = mock.MagicMock() - self.encryptor._get_key.return_value = fake__get_key(None) + self.encryptor._get_key.return_value = fake__get_key(None, fake_key) self.encryptor.attach_volume(None) mock_execute.assert_has_calls([ mock.call('cryptsetup', 'create', '--key-file=-', self.dev_name, - self.dev_path, process_input='0' * 32, + self.dev_path, process_input=fake_key, run_as_root=True, check_exit_code=True), mock.call('ln', '--symbolic', '--force', '/dev/mapper/%s' % self.dev_name, self.symlink_path, @@ -138,3 +140,31 @@ class CryptsetupEncryptorTestCase(test_base.VolumeEncryptorTestCase): mock.call('/dev/mapper/%s' % wwn)]) mock_execute.assert_called_once_with( 'cryptsetup', 'status', wwn, run_as_root=True) + + @mock.patch('nova.utils.execute') + def test_attach_volume_unmangle_passphrase(self, mock_execute): + fake_key = '0725230b' + fake_key_mangled = '72523b' + self.encryptor._get_key = mock.MagicMock() + self.encryptor._get_key.return_value = fake__get_key(None, fake_key) + + mock_execute.side_effect = [ + processutils.ProcessExecutionError(exit_code=2), # luksOpen + mock.DEFAULT, + mock.DEFAULT, + ] + + self.encryptor.attach_volume(None) + + mock_execute.assert_has_calls([ + mock.call('cryptsetup', 'create', '--key-file=-', self.dev_name, + self.dev_path, process_input=fake_key, + run_as_root=True, check_exit_code=True), + mock.call('cryptsetup', 'create', '--key-file=-', self.dev_name, + self.dev_path, process_input=fake_key_mangled, + run_as_root=True, check_exit_code=True), + mock.call('ln', '--symbolic', '--force', + '/dev/mapper/%s' % self.dev_name, self.symlink_path, + run_as_root=True, check_exit_code=True), + ]) + self.assertEqual(3, mock_execute.call_count) diff --git a/nova/volume/encryptors/cryptsetup.py b/nova/volume/encryptors/cryptsetup.py index fa690db6c..62614a847 100644 --- a/nova/volume/encryptors/cryptsetup.py +++ b/nova/volume/encryptors/cryptsetup.py @@ -14,6 +14,7 @@ # under the License. +import array import binascii import os @@ -21,7 +22,7 @@ from oslo_concurrency import processutils from oslo_log import log as logging from nova import exception -from nova.i18n import _LW +from nova.i18n import _LW, _LI from nova import utils from nova.volume.encryptors import base @@ -119,6 +120,17 @@ class CryptsetupEncryptor(base.VolumeEncryptor): utils.execute(*cmd, process_input=passphrase, check_exit_code=True, run_as_root=True) + def _get_mangled_passphrase(self, key): + """Convert the raw key into a list of unsigned int's and then a string + """ + # NOTE(lyarwood): This replicates the methods used prior to Newton to + # first encode the passphrase as a list of unsigned int's before + # decoding back into a string. This method strips any leading 0's + # of the resulting hex digit pairs, resulting in a different + # passphrase being returned. + encoded_key = array.array('B', key).tolist() + return ''.join(hex(x).replace('0x', '') for x in encoded_key) + def attach_volume(self, context, **kwargs): """Shadows the device and passes an unencrypted version to the instance. @@ -132,7 +144,16 @@ class CryptsetupEncryptor(base.VolumeEncryptor): key = self._get_key(context).get_encoded() passphrase = self._get_passphrase(key) - self._open_volume(passphrase, **kwargs) + try: + self._open_volume(passphrase, **kwargs) + except processutils.ProcessExecutionError as e: + if e.exit_code == 2: + # NOTE(lyarwood): Workaround bug#1633518 by attempting to use + # a mangled passphrase to open the device.. + LOG.info(_LI("Unable to open %s with the current passphrase, " + "attempting to use a mangled passphrase to open " + "the volume."), self.dev_path) + self._open_volume(self._get_mangled_passphrase(key), **kwargs) # modify the original symbolic link to refer to the decrypted device utils.execute('ln', '--symbolic', '--force',