121 lines
3.4 KiB
Python
121 lines
3.4 KiB
Python
"""
|
|
.. module: lemur.utils
|
|
:platform: Unix
|
|
:copyright: (c) 2015 by Netflix Inc., see AUTHORS for more
|
|
:license: Apache, see LICENSE for more details.
|
|
.. moduleauthor:: Kevin Glisson <kglisson@netflix.com>
|
|
"""
|
|
import os
|
|
from flask import current_app
|
|
from cryptography.fernet import Fernet, MultiFernet
|
|
import sqlalchemy.types as types
|
|
|
|
from contextlib import contextmanager
|
|
import tempfile
|
|
|
|
|
|
@contextmanager
|
|
def mktempfile():
|
|
with tempfile.NamedTemporaryFile(delete=False) as f:
|
|
name = f.name
|
|
|
|
try:
|
|
yield name
|
|
finally:
|
|
try:
|
|
os.unlink(name)
|
|
except OSError as e:
|
|
current_app.logger.debug("No file {0}".format(name))
|
|
|
|
|
|
@contextmanager
|
|
def mktemppath():
|
|
try:
|
|
path = os.path.join(tempfile._get_default_tempdir(), next(tempfile._get_candidate_names()))
|
|
yield path
|
|
finally:
|
|
try:
|
|
os.unlink(path)
|
|
except OSError as e:
|
|
current_app.logger.debug("No file {0}".format(path))
|
|
|
|
|
|
def get_keys():
|
|
"""
|
|
Gets the encryption keys.
|
|
|
|
This supports multiple keys to facilitate key rotation. The first
|
|
key in the list is used to encrypt. Decryption is attempted with
|
|
each key in succession.
|
|
|
|
:return:
|
|
"""
|
|
|
|
# when running lemur create_config, this code needs to work despite
|
|
# the fact that there is not a current_app with a config at that point
|
|
keys = current_app.config.get('LEMUR_ENCRYPTION_KEYS', [])
|
|
|
|
# this function is expected to return a list of keys, but we want
|
|
# to let people just specify a single key
|
|
if not isinstance(keys, list):
|
|
keys = [keys]
|
|
|
|
# make sure there is no accidental whitespace
|
|
keys = [key.strip() for key in keys]
|
|
|
|
return keys
|
|
|
|
|
|
class Vault(types.TypeDecorator):
|
|
"""
|
|
A custom SQLAlchemy column type that transparently handles encryption.
|
|
|
|
This uses the MultiFernet from the cryptography package to facilitate
|
|
key rotation. That class handles encryption and signing.
|
|
|
|
Fernet uses AES in CBC mode with 128-bit keys and PKCS7 padding. It
|
|
uses HMAC-SHA256 for ciphertext authentication. Initialization
|
|
vectors are generated using os.urandom().
|
|
"""
|
|
|
|
# required by SQLAlchemy. defines the underlying column type
|
|
impl = types.Binary
|
|
|
|
def process_bind_param(self, value, dialect):
|
|
"""
|
|
Encrypt values on the way into the database.
|
|
|
|
MultiFernet.encrypt uses the first key in the list.
|
|
"""
|
|
|
|
# we assume that the user's keys are already Fernet keys (32 byte
|
|
# keys that have been base64 encoded).
|
|
self.keys = [Fernet(key) for key in get_keys()]
|
|
|
|
if not value:
|
|
return
|
|
|
|
# ensure bytes for fernet
|
|
if isinstance(value, str):
|
|
value = value.encode('utf-8')
|
|
|
|
return MultiFernet(self.keys).encrypt(value)
|
|
|
|
def process_result_value(self, value, dialect):
|
|
"""
|
|
Decrypt values on the way out of the database.
|
|
|
|
MultiFernet tries each key until one works.
|
|
"""
|
|
|
|
# we assume that the user's keys are already Fernet keys (32 byte
|
|
# keys that have been base64 encoded).
|
|
self.keys = [Fernet(key) for key in get_keys()]
|
|
|
|
# if the value is not a string we aren't going to try to decrypt
|
|
# it. this is for the case where the column is null
|
|
if not value:
|
|
return
|
|
|
|
return MultiFernet(self.keys).decrypt(value).decode('utf8')
|