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New LUKS devices management module (#48991)

* New LUKS devices management module

- new module that uses cryptsetup (LUKS) functions for management
of encrypted devices
- unit tests included

* New LUKS devices management module

- modified interface by removing 'open' option and moving its functionality
into 'state' option
This commit is contained in:
japokorn 2019-02-15 10:25:14 +01:00 committed by John R Barker
parent 0c8c72a0bf
commit 68d43130d0
3 changed files with 744 additions and 0 deletions

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#!/usr/bin/python
# Copyright (c) 2017 Ansible Project
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type
ANSIBLE_METADATA = {'metadata_version': '1.1',
'status': ['preview'],
'supported_by': 'community'}
DOCUMENTATION = '''
---
module: luks_device
short_description: Manage encrypted (LUKS) devices
version_added: "2.8"
description:
- "Module manages L(LUKS,https://en.wikipedia.org/wiki/Linux_Unified_Key_Setup)
on given device. Supports creating, destroying, opening and closing of
LUKS container and adding or removing new keys."
options:
device:
description:
- "Device to work with (e.g. C(/dev/sda1)). Needed in most cases.
Can be omitted only when I(state=closed) together with I(name)
is provided."
type: str
state:
description:
- "Desired state of the LUKS container. Based on its value creates,
destroys, opens or closes the LUKS container on a given device."
- "I(present) will create LUKS container unless already present.
Requires I(device) and I(keyfile) options to be provided."
- "I(absent) will remove existing LUKS container if it exists.
Requires I(device) or I(name) to be specified."
- "I(opened) will unlock the LUKS container. If it does not exist
it will be created first.
Requires I(device) and I(keyfile) to be specified. Use
the I(name) option to set the name of the opened container.
Otherwise the name will be generated automatically and returned
as a part of the result."
- "I(closed) will lock the LUKS container. However if the container
does not exist it will be created.
Requires I(device) and I(keyfile) options to be provided. If
container does already exist I(device) or I(name) will suffice."
default: present
choices: [present, absent, opened, closed]
type: str
name:
description:
- "Sets container name when I(state=opened). Can be used
instead of I(device) when closing the existing container
(i.e. when I(state=closed))."
type: str
keyfile:
description:
- "Used to unlock the container and needed for most
of the operations. Parameter value is the path
to the keyfile with the passphrase."
- "BEWARE that working with keyfiles in plaintext is dangerous.
Make sure that they are protected."
type: path
new_keyfile:
description:
- "Adds additional key to given container on I(device).
Needs I(keyfile) option for authorization. LUKS container
supports up to 8 keys. Parameter value is the path
to the keyfile with the passphrase."
- "BEWARE that working with keyfiles in plaintext is dangerous.
Make sure that they are protected."
type: path
remove_keyfile:
description:
- "Removes given key from the container on I(device). Does not
remove the keyfile from filesystem.
Parameter value is the path to the keyfile with the passphrase."
- "BEWARE that it is possible to remove even the last key from the
container. Data in there will be irreversibly lost
without a warning."
- "BEWARE that working with keyfiles in plaintext is dangerous.
Make sure that they are protected."
type: path
requirements:
- "cryptsetup"
- "wipefs"
- "lsblk"
notes:
- "This module does not support check mode. The reason being that
while it is possible to chain several operations together
(e.g. 'create' and 'open'), the latter usually depends on changes
to the system done by the previous one. (LUKS cannot be opened,
when it does not exist.)"
author:
"Jan Pokorny (@japokorn)"
'''
EXAMPLES = '''
- name: create LUKS container (remains unchanged if it already exists)
luks_device:
device: "/dev/loop0"
state: "present"
keyfile: "/vault/keyfile"
- name: (create and) open the LUKS container; name it "mycrypt"
luks_device:
device: "/dev/loop0"
state: "opened"
name: "mycrypt"
keyfile: "/vault/keyfile"
- name: close the existing LUKS container "mycrypt"
luks_device:
state: "closed"
name: "mycrypt"
- name: make sure LUKS container exists and is closed
luks_device:
device: "/dev/loop0"
state: "closed"
keyfile: "/vault/keyfile"
- name: create container if it does not exist and add new key to it
luks_device:
device: "/dev/loop0"
state: "present"
keyfile: "/vault/keyfile"
new_keyfile: "/vault/keyfile2"
- name: add new key to the LUKS container (container has to exist)
luks_device:
device: "/dev/loop0"
keyfile: "/vault/keyfile"
new_keyfile: "/vault/keyfile2"
- name: remove existing key from the LUKS container
luks_device:
device: "/dev/loop0"
remove_keyfile: "/vault/keyfile2"
- name: completely remove the LUKS container and its contents
luks_device:
device: "/dev/loop0"
state: "absent"
'''
RETURN = '''
name:
description:
When I(state=opened) returns (generated or given) name
of LUKS container. Returns None if no name is supplied.
returned: success
type: str
sample: "luks-c1da9a58-2fde-4256-9d9f-6ab008b4dd1b"
'''
import re
from ansible.module_utils.basic import AnsibleModule
RETURN_CODE = 0
STDOUT = 1
STDERR = 2
# used to get <luks-name> out of lsblk output in format 'crypt <luks-name>'
# regex takes care of any possible blank characters
LUKS_NAME_REGEX = re.compile(r'\s*crypt\s+([^\s]*)\s*')
# used to get </luks/device> out of lsblk output
# in format 'device: </luks/device>'
LUKS_DEVICE_REGEX = re.compile(r'\s*device:\s+([^\s]*)\s*')
class Handler(object):
def __init__(self, module):
self._module = module
self._lsblk_bin = self._module.get_bin_path('lsblk', True)
def _run_command(self, command):
return self._module.run_command(command)
def generate_luks_name(self, device):
''' Generate name for luks based on device UUID ('luks-<UUID>').
Raises ValueError when obtaining of UUID fails.
'''
result = self._run_command([self._lsblk_bin, '-n', device, '-o', 'UUID'])
if result[RETURN_CODE] != 0:
raise ValueError('Error while generating LUKS name for %s: %s'
% (device, result[STDERR]))
dev_uuid = result[STDOUT].strip()
return 'luks-%s' % dev_uuid
class CryptHandler(Handler):
def __init__(self, module):
super(CryptHandler, self).__init__(module)
self._cryptsetup_bin = self._module.get_bin_path('cryptsetup', True)
def get_container_name_by_device(self, device):
''' obtain LUKS container name based on the device where it is located
return None if not found
raise ValueError if lsblk command fails
'''
result = self._run_command([self._lsblk_bin, device, '-nlo', 'type,name'])
if result[RETURN_CODE] != 0:
raise ValueError('Error while obtaining LUKS name for %s: %s'
% (device, result[STDERR]))
m = LUKS_NAME_REGEX.search(result[STDOUT])
try:
name = m.group(1)
except AttributeError:
name = None
return name
def get_container_device_by_name(self, name):
''' obtain device name based on the LUKS container name
return None if not found
raise ValueError if lsblk command fails
'''
# apparently each device can have only one LUKS container on it
result = self._run_command([self._cryptsetup_bin, 'status', name])
if result[RETURN_CODE] != 0:
return None
m = LUKS_DEVICE_REGEX.search(result[STDOUT])
device = m.group(1)
return device
def is_luks(self, device):
''' check if the LUKS device does exist
'''
result = self._run_command([self._cryptsetup_bin, 'isLuks', device])
return result[RETURN_CODE] == 0
def run_luks_create(self, device, keyfile):
# create a new luks container; use batch mode to auto confirm
result = self._run_command([self._cryptsetup_bin, 'luksFormat',
'-q', device, keyfile])
if result[RETURN_CODE] != 0:
raise ValueError('Error while creating LUKS on %s: %s'
% (device, result[STDERR]))
def run_luks_open(self, device, keyfile, name):
result = self._run_command([self._cryptsetup_bin, '--key-file', keyfile,
'open', '--type', 'luks', device, name])
if result[RETURN_CODE] != 0:
raise ValueError('Error while opening LUKS container on %s: %s'
% (device, result[STDERR]))
def run_luks_close(self, name):
result = self._run_command([self._cryptsetup_bin, 'close', name])
if result[RETURN_CODE] != 0:
raise ValueError('Error while closing LUKS container %s' % (name))
def run_luks_remove(self, device):
wipefs_bin = self._module.get_bin_path('wipefs', True)
name = self.get_container_name_by_device(device)
if name is not None:
self.run_luks_close(name)
result = self._run_command([wipefs_bin, '--all', device])
if result[RETURN_CODE] != 0:
raise ValueError('Error while wiping luks container %s: %s'
% (device, result[STDERR]))
def run_luks_add_key(self, device, keyfile, new_keyfile):
''' Add new key to given 'device'; authentization done using 'keyfile'
Raises ValueError when command fails
'''
result = self._run_command([self._cryptsetup_bin, 'luksAddKey', device,
new_keyfile, '--key-file', keyfile])
if result[RETURN_CODE] != 0:
raise ValueError('Error while adding new LUKS key to %s: %s'
% (device, result[STDERR]))
def run_luks_remove_key(self, device, keyfile):
''' Remove key from given device
Raises ValueError when command fails
'''
result = self._run_command([self._cryptsetup_bin, 'luksRemoveKey', device,
'-q', '--key-file', keyfile])
if result[RETURN_CODE] != 0:
raise ValueError('Error while removing LUKS key from %s: %s'
% (device, result[STDERR]))
class ConditionsHandler(Handler):
def __init__(self, module, crypthandler):
super(ConditionsHandler, self).__init__(module)
self._crypthandler = crypthandler
def luks_create(self):
return (self._module.params['device'] is not None and
self._module.params['keyfile'] is not None and
self._module.params['state'] in ('present',
'opened',
'closed') and
not self._crypthandler.is_luks(self._module.params['device']))
def opened_luks_name(self):
''' If luks is already opened, return its name.
If 'name' parameter is specified and differs
from obtained value, fail.
Return None otherwise
'''
if self._module.params['state'] != 'opened':
return None
# try to obtain luks name - it may be already opened
name = self._crypthandler.get_container_name_by_device(
self._module.params['device'])
if name is None:
# container is not open
return None
if (self._module.params['name'] is None):
# container is already opened
return name
if (name != self._module.params['name']):
# the container is already open but with different name:
# suspicious. back off
self._module.fail_json(msg="LUKS container is already opened "
"under different name '%s'." % name)
# container is opened and the names match
return name
def luks_open(self):
if (self._module.params['device'] is None or
self._module.params['keyfile'] is None or
self._module.params['state'] != 'opened'):
# conditions for open not fulfilled
return False
name = self.opened_luks_name()
if name is None:
return True
return False
def luks_close(self):
if ((self._module.params['name'] is None and
self._module.params['device'] is None) or
self._module.params['state'] != 'closed'):
# conditions for close not fulfilled
return False
if self._module.params['device'] is not None:
name = self._crypthandler.get_container_name_by_device(
self._module.params['device'])
# sucessfully getting name based on device means that luks is open
luks_is_open = name is not None
if self._module.params['name'] is not None:
device = self._crypthandler.get_container_device_by_name(
self._module.params['name'])
# sucessfully getting device based on name means that luks is open
luks_is_open = device is not None
return luks_is_open
def luks_add_key(self):
if (self._module.params['device'] is None or
self._module.params['keyfile'] is None or
self._module.params['new_keyfile'] is None):
# conditions for adding a key not fulfilled
return False
if self._module.params['state'] == 'absent':
self._module.fail_json(msg="Contradiction in setup: Asking to "
"add a key to absent LUKS.")
return True
def luks_remove_key(self):
if (self._module.params['device'] is None or
self._module.params['remove_keyfile'] is None):
# conditions for removing a key not fulfilled
return False
if self._module.params['state'] == 'absent':
self._module.fail_json(msg="Contradiction in setup: Asking to "
"remove a key from absent LUKS.")
return True
def luks_remove(self):
return (self._module.params['device'] is not None and
self._module.params['state'] == 'absent' and
self._crypthandler.is_luks(self._module.params['device']))
def run_module():
# available arguments/parameters that a user can pass
module_args = dict(
state=dict(type='str',
choices=['present', 'absent', 'opened', 'closed'],
required=False,
default='present'),
device=dict(type='str', required=False),
name=dict(type='str', required=False),
keyfile=dict(type='path', required=False),
new_keyfile=dict(type='path', required=False),
remove_keyfile=dict(type='path', required=False)
)
# seed the result dict in the object
result = dict(
changed=False,
name=None
)
module = AnsibleModule(argument_spec=module_args,
supports_check_mode=False)
crypt = CryptHandler(module)
conditions = ConditionsHandler(module, crypt)
# The conditions are in order to allow more operations in one run.
# (e.g. create luks and add a key to it)
# luks create
if conditions.luks_create():
try:
crypt.run_luks_create(module.params['device'],
module.params['keyfile'])
except ValueError as e:
module.fail_json(msg="luks_device error: %s" % e)
result['changed'] = True
# luks open
name = conditions.opened_luks_name()
if name is not None:
result['name'] = name
if conditions.luks_open():
name = module.params['name']
if name is None:
try:
name = crypt.generate_luks_name(module.params['device'])
except ValueError as e:
module.fail_json(msg="luks_device error: %s" % e)
try:
crypt.run_luks_open(module.params['device'],
module.params['keyfile'],
name)
except ValueError as e:
module.fail_json(msg="luks_device error: %s" % e)
result['name'] = name
result['changed'] = True
# luks close
if conditions.luks_close():
if module.params['device'] is not None:
try:
name = crypt.get_container_name_by_device(
module.params['device'])
except ValueError as e:
module.fail_json(msg="luks_device error: %s" % e)
else:
name = module.params['name']
try:
crypt.run_luks_close(name)
except ValueError as e:
module.fail_json(msg="luks_device error: %s" % e)
result['changed'] = True
# luks add key
if conditions.luks_add_key():
try:
crypt.run_luks_add_key(module.params['device'],
module.params['keyfile'],
module.params['new_keyfile'])
except ValueError as e:
module.fail_json(msg="luks_device error: %s" % e)
result['changed'] = True
# luks remove key
if conditions.luks_remove_key():
try:
crypt.run_luks_remove_key(module.params['device'],
module.params['remove_keyfile'])
except ValueError as e:
module.fail_json(msg="luks_device error: %s" % e)
result['changed'] = True
# luks remove
if conditions.luks_remove():
try:
crypt.run_luks_remove(module.params['device'])
except ValueError as e:
module.fail_json(msg="luks_device error: %s" % e)
result['changed'] = True
# Success - return result
module.exit_json(**result)
def main():
run_module()
if __name__ == '__main__':
main()

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import pytest
from ansible.modules.crypto import luks_device
class DummyModule(object):
# module to mock AnsibleModule class
def __init__(self):
self.params = dict()
def fail_json(self, msg=""):
raise ValueError(msg)
def get_bin_path(self, command, dummy):
return command
# ===== Handler & CryptHandler methods tests =====
def test_generate_luks_name(monkeypatch):
module = DummyModule()
monkeypatch.setattr(luks_device.Handler, "_run_command",
lambda x, y: [0, "UUID", ""])
crypt = luks_device.CryptHandler(module)
assert crypt.generate_luks_name("/dev/dummy") == "luks-UUID"
def test_get_container_name_by_device(monkeypatch):
module = DummyModule()
monkeypatch.setattr(luks_device.Handler, "_run_command",
lambda x, y: [0, "crypt container_name", ""])
crypt = luks_device.CryptHandler(module)
assert crypt.get_container_name_by_device("/dev/dummy") == "container_name"
def test_get_container_device_by_name(monkeypatch):
module = DummyModule()
monkeypatch.setattr(luks_device.Handler, "_run_command",
lambda x, y: [0, "device: /dev/luksdevice", ""])
crypt = luks_device.CryptHandler(module)
assert crypt.get_container_device_by_name("dummy") == "/dev/luksdevice"
def test_run_luks_remove(monkeypatch):
def run_command_check(self, command):
# check that wipefs command is actually called
assert command[0] == "wipefs"
return [0, "", ""]
module = DummyModule()
monkeypatch.setattr(luks_device.CryptHandler,
"get_container_name_by_device",
lambda x, y: None)
monkeypatch.setattr(luks_device.Handler,
"_run_command",
run_command_check)
crypt = luks_device.CryptHandler(module)
crypt.run_luks_remove("dummy")
# ===== ConditionsHandler methods data and tests =====
# device, key, state, is_luks, expected
LUKS_CREATE_DATA = (
("dummy", "key", "present", False, True),
(None, "key", "present", False, False),
("dummy", None, "present", False, False),
("dummy", "key", "absent", False, False),
("dummy", "key", "opened", True, False),
("dummy", "key", "closed", True, False),
("dummy", "key", "present", True, False))
# device, state, is_luks, expected
LUKS_REMOVE_DATA = (
("dummy", "absent", True, True),
(None, "absent", True, False),
("dummy", "present", True, False),
("dummy", "absent", False, False))
# device, key, state, name, name_by_dev, expected
LUKS_OPEN_DATA = (
("dummy", "key", "present", "name", None, False),
("dummy", "key", "absent", "name", None, False),
("dummy", "key", "closed", "name", None, False),
("dummy", "key", "opened", "name", None, True),
(None, "key", "opened", "name", None, False),
("dummy", None, "opened", "name", None, False),
("dummy", "key", "opened", "name", "name", False),
("dummy", "key", "opened", "beer", "name", "exception"))
# device, dev_by_name, name, name_by_dev, state, expected
LUKS_CLOSE_DATA = (
("dummy", "dummy", "name", "name", "present", False),
("dummy", "dummy", "name", "name", "absent", False),
("dummy", "dummy", "name", "name", "opened", False),
("dummy", "dummy", "name", "name", "closed", True),
(None, "dummy", "name", "name", "closed", True),
("dummy", "dummy", None, "name", "closed", True),
(None, "dummy", None, "name", "closed", False))
# device, key, new_key, state, expected
LUKS_ADD_KEY_DATA = (
("dummy", "key", "new_key", "present", True),
(None, "key", "new_key", "present", False),
("dummy", None, "new_key", "present", False),
("dummy", "key", None, "present", False),
("dummy", "key", "new_key", "absent", "exception"))
# device, remove_key, state, expected
LUKS_REMOVE_KEY_DATA = (
("dummy", "key", "present", True),
(None, "key", "present", False),
("dummy", None, "present", False),
("dummy", "key", "absent", "exception"))
@pytest.mark.parametrize("device, keyfile, state, is_luks, expected",
((d[0], d[1], d[2], d[3], d[4])
for d in LUKS_CREATE_DATA))
def test_luks_create(device, keyfile, state, is_luks, expected, monkeypatch):
module = DummyModule()
module.params["device"] = device
module.params["keyfile"] = keyfile
module.params["state"] = state
monkeypatch.setattr(luks_device.CryptHandler, "is_luks",
lambda x, y: is_luks)
crypt = luks_device.CryptHandler(module)
conditions = luks_device.ConditionsHandler(module, crypt)
assert conditions.luks_create() == expected
@pytest.mark.parametrize("device, state, is_luks, expected",
((d[0], d[1], d[2], d[3])
for d in LUKS_REMOVE_DATA))
def test_luks_remove(device, state, is_luks, expected, monkeypatch):
module = DummyModule()
module.params["device"] = device
module.params["state"] = state
monkeypatch.setattr(luks_device.CryptHandler, "is_luks",
lambda x, y: is_luks)
crypt = luks_device.CryptHandler(module)
conditions = luks_device.ConditionsHandler(module, crypt)
assert conditions.luks_remove() == expected
@pytest.mark.parametrize("device, keyfile, state, name, "
"name_by_dev, expected",
((d[0], d[1], d[2], d[3], d[4], d[5])
for d in LUKS_OPEN_DATA))
def test_luks_open(device, keyfile, state, name, name_by_dev,
expected, monkeypatch):
module = DummyModule()
module.params["device"] = device
module.params["keyfile"] = keyfile
module.params["state"] = state
module.params["name"] = name
monkeypatch.setattr(luks_device.CryptHandler,
"get_container_name_by_device",
lambda x, y: name_by_dev)
crypt = luks_device.CryptHandler(module)
conditions = luks_device.ConditionsHandler(module, crypt)
try:
assert conditions.luks_open() == expected
except ValueError:
assert expected == "exception"
@pytest.mark.parametrize("device, dev_by_name, name, name_by_dev, "
"state, expected",
((d[0], d[1], d[2], d[3], d[4], d[5])
for d in LUKS_CLOSE_DATA))
def test_luks_close(device, dev_by_name, name, name_by_dev, state,
expected, monkeypatch):
module = DummyModule()
module.params["device"] = device
module.params["name"] = name
module.params["state"] = state
monkeypatch.setattr(luks_device.CryptHandler,
"get_container_name_by_device",
lambda x, y: name_by_dev)
monkeypatch.setattr(luks_device.CryptHandler,
"get_container_device_by_name",
lambda x, y: dev_by_name)
crypt = luks_device.CryptHandler(module)
conditions = luks_device.ConditionsHandler(module, crypt)
assert conditions.luks_close() == expected
@pytest.mark.parametrize("device, keyfile, new_keyfile, state, expected",
((d[0], d[1], d[2], d[3], d[4])
for d in LUKS_ADD_KEY_DATA))
def test_luks_add_key(device, keyfile, new_keyfile, state, expected, monkeypatch):
module = DummyModule()
module.params["device"] = device
module.params["keyfile"] = keyfile
module.params["new_keyfile"] = new_keyfile
module.params["state"] = state
conditions = luks_device.ConditionsHandler(module, module)
try:
assert conditions.luks_add_key() == expected
except ValueError:
assert expected == "exception"
@pytest.mark.parametrize("device, remove_keyfile, state, expected",
((d[0], d[1], d[2], d[3])
for d in LUKS_REMOVE_KEY_DATA))
def test_luks_remove_key(device, remove_keyfile, state, expected, monkeypatch):
module = DummyModule()
module.params["device"] = device
module.params["remove_keyfile"] = remove_keyfile
module.params["state"] = state
conditions = luks_device.ConditionsHandler(module, module)
try:
assert conditions.luks_remove_key() == expected
except ValueError:
assert expected == "exception"