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Diffstat (limited to 'python/olm/sas.py')
| -rw-r--r-- | python/olm/sas.py | 245 |
1 files changed, 0 insertions, 245 deletions
diff --git a/python/olm/sas.py b/python/olm/sas.py deleted file mode 100644 index cf2a443..0000000 --- a/python/olm/sas.py +++ /dev/null @@ -1,245 +0,0 @@ -# -*- coding: utf-8 -*- -# libolm python bindings -# Copyright © 2019 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 SAS module. - -This module contains functions to perform key verification using the Short -Authentication String (SAS) method. - -Examples: - >>> sas = Sas() - >>> bob_key = "3p7bfXt9wbTTW2HC7OQ1Nz+DQ8hbeGdNrfx+FG+IK08" - >>> message = "Hello world!" - >>> extra_info = "MAC" - >>> sas_alice.set_their_pubkey(bob_key) - >>> sas_alice.calculate_mac(message, extra_info) - >>> sas_alice.generate_bytes(extra_info, 5) - -""" - -from builtins import bytes -from functools import wraps -from typing import Optional - -from future.utils import bytes_to_native_str - -from _libolm import ffi, lib - -from ._compat import URANDOM, to_bytearray, to_bytes -from ._finalize import track_for_finalization - - -def _clear_sas(sas): - # type: (ffi.cdata) -> None - lib.olm_clear_sas(sas) - - -class OlmSasError(Exception): - """libolm Sas error exception.""" - - -class Sas(object): - """libolm Short Authenticaton String (SAS) class.""" - - def __init__(self, other_users_pubkey=None): - # type: (Optional[str]) -> None - """Create a new SAS object. - - Args: - other_users_pubkey(str, optional): The other users public key, this - key is necesary to generate bytes for the authentication string - as well as to calculate the MAC. - - Raises OlmSasError on failure. - - """ - self._buf = ffi.new("char[]", lib.olm_sas_size()) - self._sas = lib.olm_sas(self._buf) - track_for_finalization(self, self._sas, _clear_sas) - - random_length = lib.olm_create_sas_random_length(self._sas) - random = URANDOM(random_length) - - self._create_sas(random, random_length) - - if other_users_pubkey: - self.set_their_pubkey(other_users_pubkey) - - def _create_sas(self, buffer, buffer_length): - self._check_error( - lib.olm_create_sas( - self._sas, - ffi.from_buffer(buffer), - buffer_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_sas_last_error(self._sas)))) - - raise OlmSasError(last_error) - - @property - def pubkey(self): - # type: () -> str - """Get the public key for the SAS object. - - This returns the public key of the SAS object that can then be shared - with another user to perform the authentication process. - - Raises OlmSasError on failure. - - """ - pubkey_length = lib.olm_sas_pubkey_length(self._sas) - pubkey_buffer = ffi.new("char[]", pubkey_length) - - self._check_error( - lib.olm_sas_get_pubkey(self._sas, pubkey_buffer, pubkey_length) - ) - - return bytes_to_native_str(ffi.unpack(pubkey_buffer, pubkey_length)) - - @property - def other_key_set(self): - # type: () -> bool - """Check if the other user's pubkey has been set. - """ - return lib.olm_sas_is_their_key_set(self._sas) == 1 - - def set_their_pubkey(self, key): - # type: (str) -> None - """Set the public key of the other user. - - This sets the public key of the other user, it needs to be set before - bytes can be generated for the authentication string and a MAC can be - calculated. - - Args: - key (str): The other users public key. - - Raises OlmSasError on failure. - - """ - byte_key = to_bytearray(key) - - self._check_error( - lib.olm_sas_set_their_key( - self._sas, - ffi.from_buffer(byte_key), - len(byte_key) - ) - ) - - def generate_bytes(self, extra_info, length): - # type: (str, int) -> bytes - """Generate bytes to use for the short authentication string. - - Args: - extra_info (str): Extra information to mix in when generating the - bytes. - length (int): The number of bytes to generate. - - Raises OlmSasError if the other users persons public key isn't set or - an internal Olm error happens. - - """ - if length < 1: - raise ValueError("The length needs to be a positive integer value") - - byte_info = to_bytearray(extra_info) - out_buffer = ffi.new("char[]", length) - - self._check_error( - lib.olm_sas_generate_bytes( - self._sas, - ffi.from_buffer(byte_info), - len(byte_info), - out_buffer, - length - ) - ) - - return ffi.unpack(out_buffer, length) - - def calculate_mac(self, message, extra_info): - # type: (str, str) -> str - """Generate a message authentication code based on the shared secret. - - Args: - message (str): The message to produce the authentication code for. - extra_info (str): Extra information to mix in when generating the - MAC - - Raises OlmSasError on failure. - - """ - byte_message = to_bytes(message) - byte_info = to_bytes(extra_info) - - mac_length = lib.olm_sas_mac_length(self._sas) - mac_buffer = ffi.new("char[]", mac_length) - - self._check_error( - lib.olm_sas_calculate_mac( - self._sas, - ffi.from_buffer(byte_message), - len(byte_message), - ffi.from_buffer(byte_info), - len(byte_info), - mac_buffer, - mac_length - ) - ) - return bytes_to_native_str(ffi.unpack(mac_buffer, mac_length)) - - def calculate_mac_long_kdf(self, message, extra_info): - # type: (str, str) -> str - """Generate a message authentication code based on the shared secret. - - This function should not be used unless compatibility with an older - non-tagged Olm version is required. - - Args: - message (str): The message to produce the authentication code for. - extra_info (str): Extra information to mix in when generating the - MAC - - Raises OlmSasError on failure. - - """ - byte_message = to_bytes(message) - byte_info = to_bytes(extra_info) - - mac_length = lib.olm_sas_mac_length(self._sas) - mac_buffer = ffi.new("char[]", mac_length) - - self._check_error( - lib.olm_sas_calculate_mac_long_kdf( - self._sas, - ffi.from_buffer(byte_message), - len(byte_message), - ffi.from_buffer(byte_info), - len(byte_info), - mac_buffer, - mac_length - ) - ) - return bytes_to_native_str(ffi.unpack(mac_buffer, mac_length)) |