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# -*- coding: utf-8 -*-
# libolm python bindings
# Copyright © 2015-2017 OpenMarket Ltd
# Copyright © 2018 Damir Jelić <poljar@termina.org.uk>
#
# 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.
"""libolm Account module.
This module contains the account part of the Olm library. It contains a single
Account class which handles the creation of new accounts as well as the storing
and restoring of them.
Examples:
>>> acc = Account()
>>> account.identity_keys()
>>> account.generate_one_time_keys(1)
"""
import json
# pylint: disable=redefined-builtin,unused-import
from builtins import bytes, super
from typing import AnyStr, Dict, Optional, Type
from future.utils import bytes_to_native_str
# pylint: disable=no-name-in-module
from _libolm import ffi, lib # type: ignore
from ._compat import URANDOM, to_bytes
from ._finalize import track_for_finalization
# This is imported only for type checking purposes
if False:
from .session import Session # pragma: no cover
def _clear_account(account):
# type: (ffi.cdata) -> None
lib.olm_clear_account(account)
class OlmAccountError(Exception):
"""libolm Account error exception."""
class Account(object):
"""libolm Account class."""
def __new__(cls):
# type: (Type[Account]) -> Account
obj = super().__new__(cls)
obj._buf = ffi.new("char[]", lib.olm_account_size())
obj._account = lib.olm_account(obj._buf)
track_for_finalization(obj, obj._account, _clear_account)
return obj
def __init__(self):
# type: () -> None
"""Create a new Olm account.
Creates a new account and its matching identity key pair.
Raises OlmAccountError on failure. If there weren't enough random bytes
for the account creation the error message for the exception will be
NOT_ENOUGH_RANDOM.
"""
# This is needed to silence mypy not knowing the type of _account.
# There has to be a better way for this.
if False: # pragma: no cover
self._account = self._account # type: ffi.cdata
random_length = lib.olm_create_account_random_length(self._account)
random = URANDOM(random_length)
random_buffer = ffi.new("char[]", random)
self._check_error(
lib.olm_create_account(self._account, random_buffer,
random_length))
def _check_error(self, ret):
# type: (int) -> None
if ret != lib.olm_error():
return
last_error = bytes_to_native_str(
ffi.string((lib.olm_account_last_error(self._account))))
raise OlmAccountError(last_error)
def pickle(self, passphrase=""):
# type: (Optional[str]) -> bytes
"""Store an Olm account.
Stores an account as a base64 string. Encrypts the account using the
supplied passphrase. Returns a byte object containing the base64
encoded string of the pickled account. Raises OlmAccountError on
failure.
Args:
passphrase(str, optional): The passphrase to be used to encrypt
the account.
"""
byte_key = bytes(passphrase, "utf-8") if passphrase else b""
key_buffer = ffi.new("char[]", byte_key)
pickle_length = lib.olm_pickle_account_length(self._account)
pickle_buffer = ffi.new("char[]", pickle_length)
self._check_error(
lib.olm_pickle_account(self._account, key_buffer, len(byte_key),
pickle_buffer, pickle_length))
return ffi.unpack(pickle_buffer, pickle_length)
@classmethod
def from_pickle(cls, pickle, passphrase=""):
# type: (bytes, Optional[str]) -> Account
"""Load a previously stored olm account.
Loads an account from a pickled base64-encoded string and returns an
Account object. Decrypts the account using the supplied passphrase.
Raises OlmAccountError on failure. If the passphrase doesn't match the
one used to encrypt the account then the error message for the
exception will be "BAD_ACCOUNT_KEY". If the base64 couldn't be decoded
then the error message will be "INVALID_BASE64".
Args:
pickle(bytes): Base64 encoded byte string containing the pickled
account
passphrase(str, optional): The passphrase used to encrypt the
account.
"""
if not pickle:
raise ValueError("Pickle can't be empty")
byte_key = bytes(passphrase, "utf-8") if passphrase else b""
key_buffer = ffi.new("char[]", byte_key)
pickle_buffer = ffi.new("char[]", pickle)
obj = cls.__new__(cls)
ret = lib.olm_unpickle_account(obj._account, key_buffer, len(byte_key),
pickle_buffer, len(pickle))
obj._check_error(ret)
return obj
@property
def identity_keys(self):
# type: () -> Dict[str, str]
"""dict: Public part of the identity keys of the account."""
out_length = lib.olm_account_identity_keys_length(self._account)
out_buffer = ffi.new("char[]", out_length)
self._check_error(
lib.olm_account_identity_keys(self._account, out_buffer,
out_length))
return json.loads(ffi.unpack(out_buffer, out_length).decode("utf-8"))
def sign(self, message):
# type: (AnyStr) -> str
"""Signs a message with this account.
Signs a message with the private ed25519 identity key of this account.
Returns the signature.
Raises OlmAccountError on failure.
Args:
message(str): The message to sign.
"""
bytes_message = to_bytes(message)
out_length = lib.olm_account_signature_length(self._account)
message_buffer = ffi.new("char[]", bytes_message)
out_buffer = ffi.new("char[]", out_length)
self._check_error(
lib.olm_account_sign(self._account, message_buffer,
len(bytes_message), out_buffer, out_length))
return bytes_to_native_str(ffi.unpack(out_buffer, out_length))
@property
def max_one_time_keys(self):
# type: () -> int
"""int: The maximum number of one-time keys the account can store."""
return lib.olm_account_max_number_of_one_time_keys(self._account)
def mark_keys_as_published(self):
# type: () -> None
"""Mark the current set of one-time keys as being published."""
lib.olm_account_mark_keys_as_published(self._account)
def generate_one_time_keys(self, count):
# type: (int) -> None
"""Generate a number of new one-time keys.
If the total number of keys stored by this account exceeds
max_one_time_keys() then the old keys are discarded.
Raises OlmAccountError on error.
Args:
count(int): The number of keys to generate.
"""
random_length = lib.olm_account_generate_one_time_keys_random_length(
self._account, count)
random = URANDOM(random_length)
random_buffer = ffi.new("char[]", random)
self._check_error(
lib.olm_account_generate_one_time_keys(
self._account, count, random_buffer, random_length))
@property
def one_time_keys(self):
# type: () -> Dict[str, Dict[str, str]]
"""dict: The public part of the one-time keys for this account."""
out_length = lib.olm_account_one_time_keys_length(self._account)
out_buffer = ffi.new("char[]", out_length)
self._check_error(
lib.olm_account_one_time_keys(self._account, out_buffer,
out_length))
return json.loads(ffi.unpack(out_buffer, out_length).decode("utf-8"))
def remove_one_time_keys(self, session):
# type: (Session) -> None
"""Remove used one-time keys.
Removes the one-time keys that the session used from the account.
Raises OlmAccountError on failure. If the account doesn't have any
matching one-time keys then the error message of the exception will be
"BAD_MESSAGE_KEY_ID".
Args:
session(Session): An Olm Session object that was created with this
account.
"""
self._check_error(lib.olm_remove_one_time_keys(self._account,
session._session))
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