mirror of https://git.matrix.org/git/olm.git
Merge branch 'python-sas'
Damir Jelić
commit
086133f39a
|
|
@ -1,4 +1,5 @@
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|||
include include/olm/olm.h
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include include/olm/pk.h
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include include/olm/sas.h
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include Makefile
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include olm_build.py
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|
|
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|
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@ -12,7 +12,10 @@ include/olm/olm.h: $(OLM_HEADERS)
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include/olm/pk.h: include/olm/olm.h ../include/olm/pk.h
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$(CPP) -I dummy -I ../include ../include/olm/pk.h -o include/olm/pk.h
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headers: include/olm/olm.h include/olm/pk.h
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include/olm/sas.h: include/olm/olm.h ../include/olm/sas.h
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$(CPP) -I dummy -I ../include ../include/olm/sas.h -o include/olm/sas.h
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headers: include/olm/olm.h include/olm/pk.h include/olm/sas.h
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olm-python2: headers
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DEVELOP=$(DEVELOP) python2 setup.py build
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|
|
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@ -21,7 +21,7 @@ Olm Python bindings
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| © Copyright 2015-2017 by OpenMarket Ltd
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| © Copyright 2018 by Damir Jelić
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"""
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from .utility import ed25519_verify, OlmVerifyError
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from .utility import ed25519_verify, OlmVerifyError, OlmHashError, sha256
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from .account import Account, OlmAccountError
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from .session import (
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Session,
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@ -43,3 +43,4 @@ from .pk import (
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PkEncryptionError,
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PkDecryptionError
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)
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from .sas import Sas, OlmSasError
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|
|
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|
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@ -0,0 +1,257 @@
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# -*- coding: utf-8 -*-
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# libolm python bindings
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# Copyright © 2019 Damir Jelić <poljar@termina.org.uk>
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""libolm SAS module.
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This module contains functions to perform key verification using the Short
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Authentication String (SAS) method.
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Examples:
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>>> sas = Sas()
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>>> bob_key = "3p7bfXt9wbTTW2HC7OQ1Nz+DQ8hbeGdNrfx+FG+IK08"
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>>> message = "Hello world!"
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>>> extra_info = "MAC"
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>>> sas_alice.set_their_pubkey(bob_key)
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>>> sas_alice.calculate_mac(message, extra_info)
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>>> sas_alice.generate_bytes(extra_info, 5)
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"""
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from functools import wraps
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from builtins import bytes
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from typing import Optional
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from future.utils import bytes_to_native_str
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from _libolm import ffi, lib
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from ._compat import URANDOM, to_bytes, to_bytearray
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from ._finalize import track_for_finalization
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def other_pubkey_set(func):
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"""Ensure that the other pubkey is added to the Sas object."""
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@wraps(func)
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def wrapper(self, *args, **kwargs):
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if not self.other_key_set:
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raise OlmSasError("The other public key isn't set.")
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return func(self, *args, **kwargs)
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return wrapper
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def _clear_sas(sas):
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# type: (ffi.cdata) -> None
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lib.olm_clear_sas(sas)
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class OlmSasError(Exception):
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"""libolm Sas error exception."""
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class Sas(object):
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"""libolm Short Authenticaton String (SAS) class."""
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def __init__(self, other_users_pubkey=None):
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# type: (Optional[str]) -> None
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"""Create a new SAS object.
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Args:
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other_users_pubkey(str, optional): The other users public key, this
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key is necesary to generate bytes for the authentication string
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as well as to calculate the MAC.
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Attributes:
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other_key_set (bool): A boolean flag that tracks if we set the
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other users public key for this SAS object.
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Raises OlmSasError on failure.
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"""
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self._buf = ffi.new("char[]", lib.olm_sas_size())
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self._sas = lib.olm_sas(self._buf)
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self.other_key_set = False
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track_for_finalization(self, self._sas, _clear_sas)
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random_length = lib.olm_create_sas_random_length(self._sas)
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random = URANDOM(random_length)
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self._create_sas(random, random_length)
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if other_users_pubkey:
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self.set_their_pubkey(other_users_pubkey)
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def _create_sas(self, buffer, buffer_length):
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self._check_error(
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lib.olm_create_sas(
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self._sas,
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ffi.from_buffer(buffer),
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buffer_length
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)
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)
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def _check_error(self, ret):
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# type: (int) -> None
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if ret != lib.olm_error():
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return
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last_error = bytes_to_native_str(
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ffi.string((lib.olm_sas_last_error(self._sas))))
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raise OlmSasError(last_error)
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@property
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def pubkey(self):
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# type: () -> str
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"""Get the public key for the SAS object.
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This returns the public key of the SAS object that can then be shared
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with another user to perform the authentication process.
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Raises OlmSasError on failure.
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"""
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pubkey_length = lib.olm_sas_pubkey_length(self._sas)
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pubkey_buffer = ffi.new("char[]", pubkey_length)
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self._check_error(
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lib.olm_sas_get_pubkey(self._sas, pubkey_buffer, pubkey_length)
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)
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return bytes_to_native_str(ffi.unpack(pubkey_buffer, pubkey_length))
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def set_their_pubkey(self, key):
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# type: (str) -> None
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"""Set the public key of the other user.
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This sets the public key of the other user, it needs to be set before
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bytes can be generated for the authentication string and a MAC can be
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calculated.
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Args:
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key (str): The other users public key.
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Raises OlmSasError on failure.
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"""
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byte_key = to_bytearray(key)
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self._check_error(
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lib.olm_sas_set_their_key(
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self._sas,
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ffi.from_buffer(byte_key),
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len(byte_key)
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)
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)
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self.other_key_set = True
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@other_pubkey_set
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def generate_bytes(self, extra_info, length):
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# type: (str, int) -> bytes
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"""Generate bytes to use for the short authentication string.
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Args:
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extra_info (str): Extra information to mix in when generating the
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bytes.
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length (int): The number of bytes to generate.
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Raises OlmSasError if the other users persons public key isn't set or
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an internal Olm error happens.
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"""
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if length < 1:
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raise ValueError("The length needs to be a positive integer value")
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byte_info = to_bytearray(extra_info)
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out_buffer = ffi.new("char[]", length)
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self._check_error(
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lib.olm_sas_generate_bytes(
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self._sas,
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ffi.from_buffer(byte_info),
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len(byte_info),
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out_buffer,
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length
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)
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)
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return ffi.unpack(out_buffer, length)
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@other_pubkey_set
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def calculate_mac(self, message, extra_info):
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# type: (str, str) -> str
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"""Generate a message authentication code based on the shared secret.
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Args:
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message (str): The message to produce the authentication code for.
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extra_info (str): Extra information to mix in when generating the
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MAC
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Raises OlmSasError on failure.
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"""
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byte_message = to_bytes(message)
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byte_info = to_bytes(extra_info)
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mac_length = lib.olm_sas_mac_length(self._sas)
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mac_buffer = ffi.new("char[]", mac_length)
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self._check_error(
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lib.olm_sas_calculate_mac(
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self._sas,
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ffi.from_buffer(byte_message),
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len(byte_message),
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ffi.from_buffer(byte_info),
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len(byte_info),
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mac_buffer,
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mac_length
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)
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)
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return bytes_to_native_str(ffi.unpack(mac_buffer, mac_length))
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@other_pubkey_set
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def calculate_mac_long_kdf(self, message, extra_info):
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# type: (str, str) -> str
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"""Generate a message authentication code based on the shared secret.
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This function should not be used unless compatibility with an older
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non-tagged Olm version is required.
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Args:
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message (str): The message to produce the authentication code for.
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extra_info (str): Extra information to mix in when generating the
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MAC
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Raises OlmSasError on failure.
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"""
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byte_message = to_bytes(message)
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byte_info = to_bytes(extra_info)
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mac_length = lib.olm_sas_mac_length(self._sas)
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mac_buffer = ffi.new("char[]", mac_length)
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self._check_error(
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lib.olm_sas_calculate_mac_long_kdf(
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self._sas,
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ffi.from_buffer(byte_message),
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len(byte_message),
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ffi.from_buffer(byte_info),
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len(byte_info),
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mac_buffer,
|
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mac_length
|
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)
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)
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return bytes_to_native_str(ffi.unpack(mac_buffer, mac_length))
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|
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@ -32,6 +32,7 @@ Examples:
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# pylint: disable=redefined-builtin,unused-import
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from typing import AnyStr, Type
|
||||
from future.utils import bytes_to_native_str
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# pylint: disable=no-name-in-module
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from _libolm import ffi, lib # type: ignore
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|
|
@ -49,6 +50,10 @@ class OlmVerifyError(Exception):
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"""libolm signature verification exception."""
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|
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|
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class OlmHashError(Exception):
|
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"""libolm hash calculation exception."""
|
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|
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class _Utility(object):
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# pylint: disable=too-few-public-methods
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"""libolm Utility class."""
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|
|
@ -64,12 +69,12 @@ class _Utility(object):
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track_for_finalization(cls, cls._utility, _clear_utility)
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@classmethod
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def _check_error(cls, ret):
|
||||
# type: (int) -> None
|
||||
def _check_error(cls, ret, error_class):
|
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# type: (int, Type) -> None
|
||||
if ret != lib.olm_error():
|
||||
return
|
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|
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raise OlmVerifyError("{}".format(
|
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raise error_class("{}".format(
|
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ffi.string(lib.olm_utility_last_error(
|
||||
cls._utility)).decode("utf-8")))
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||||
|
||||
|
|
@ -84,18 +89,41 @@ class _Utility(object):
|
|||
byte_signature = to_bytearray(signature)
|
||||
|
||||
try:
|
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cls._check_error(
|
||||
lib.olm_ed25519_verify(cls._utility, byte_key, len(byte_key),
|
||||
ffi.from_buffer(byte_message),
|
||||
len(byte_message),
|
||||
ffi.from_buffer(byte_signature),
|
||||
len(byte_signature)))
|
||||
ret = lib.olm_ed25519_verify(
|
||||
cls._utility,
|
||||
byte_key,
|
||||
len(byte_key),
|
||||
ffi.from_buffer(byte_message),
|
||||
len(byte_message),
|
||||
ffi.from_buffer(byte_signature),
|
||||
len(byte_signature)
|
||||
)
|
||||
|
||||
cls._check_error(ret, OlmVerifyError)
|
||||
|
||||
finally:
|
||||
# clear out copies of the message, which may be a plaintext
|
||||
if byte_message is not message:
|
||||
for i in range(0, len(byte_message)):
|
||||
byte_message[i] = 0
|
||||
|
||||
@classmethod
|
||||
def _sha256(cls, input):
|
||||
# type: (Type[_Utility], AnyStr) -> str
|
||||
if not cls._utility:
|
||||
cls._allocate()
|
||||
|
||||
byte_input = to_bytes(input)
|
||||
hash_length = lib.olm_sha256_length(cls._utility)
|
||||
hash = ffi.new("char[]", hash_length)
|
||||
|
||||
ret = lib.olm_sha256(cls._utility, byte_input, len(byte_input),
|
||||
hash, hash_length)
|
||||
|
||||
cls._check_error(ret, OlmHashError)
|
||||
|
||||
return bytes_to_native_str(ffi.unpack(hash, hash_length))
|
||||
|
||||
|
||||
def ed25519_verify(key, message, signature):
|
||||
# type: (AnyStr, AnyStr, AnyStr) -> None
|
||||
|
|
@ -109,3 +137,14 @@ def ed25519_verify(key, message, signature):
|
|||
signature(bytes): The message signature.
|
||||
"""
|
||||
return _Utility._ed25519_verify(key, message, signature)
|
||||
|
||||
|
||||
def sha256(input_string):
|
||||
# type: (AnyStr) -> str
|
||||
"""Calculate the SHA-256 hash of the input and encodes it as base64.
|
||||
|
||||
Args:
|
||||
input_string(str): The input for which the hash will be calculated.
|
||||
|
||||
"""
|
||||
return _Utility._sha256(input_string)
|
||||
|
|
|
|||
|
|
@ -43,6 +43,7 @@ ffibuilder.set_source(
|
|||
#include <olm/inbound_group_session.h>
|
||||
#include <olm/outbound_group_session.h>
|
||||
#include <olm/pk.h>
|
||||
#include <olm/sas.h>
|
||||
""",
|
||||
libraries=["olm"],
|
||||
extra_compile_args=compile_args,
|
||||
|
|
@ -54,5 +55,8 @@ with open(os.path.join(PATH, "include/olm/olm.h")) as f:
|
|||
with open(os.path.join(PATH, "include/olm/pk.h")) as f:
|
||||
ffibuilder.cdef(f.read(), override=True)
|
||||
|
||||
with open(os.path.join(PATH, "include/olm/sas.h")) as f:
|
||||
ffibuilder.cdef(f.read(), override=True)
|
||||
|
||||
if __name__ == "__main__":
|
||||
ffibuilder.compile(verbose=True)
|
||||
|
|
|
|||
|
|
@ -0,0 +1,99 @@
|
|||
from builtins import bytes
|
||||
|
||||
import pytest
|
||||
|
||||
from olm import OlmSasError, Sas
|
||||
|
||||
MESSAGE = "Test message"
|
||||
EXTRA_INFO = "extra_info"
|
||||
|
||||
|
||||
class TestClass(object):
|
||||
def test_sas_creation(self):
|
||||
sas = Sas()
|
||||
assert sas.pubkey
|
||||
|
||||
def test_other_key_setting(self):
|
||||
sas_alice = Sas()
|
||||
sas_bob = Sas()
|
||||
|
||||
assert not sas_alice.other_key_set
|
||||
sas_alice.set_their_pubkey(sas_bob.pubkey)
|
||||
assert sas_alice.other_key_set
|
||||
|
||||
def test_bytes_generating(self):
|
||||
sas_alice = Sas()
|
||||
sas_bob = Sas(sas_alice.pubkey)
|
||||
|
||||
assert sas_bob.other_key_set
|
||||
|
||||
with pytest.raises(OlmSasError):
|
||||
sas_alice.generate_bytes(EXTRA_INFO, 5)
|
||||
|
||||
sas_alice.set_their_pubkey(sas_bob.pubkey)
|
||||
|
||||
with pytest.raises(ValueError):
|
||||
sas_alice.generate_bytes(EXTRA_INFO, 0)
|
||||
|
||||
alice_bytes = sas_alice.generate_bytes(EXTRA_INFO, 5)
|
||||
bob_bytes = sas_bob.generate_bytes(EXTRA_INFO, 5)
|
||||
|
||||
assert alice_bytes == bob_bytes
|
||||
|
||||
def test_mac_generating(self):
|
||||
sas_alice = Sas()
|
||||
sas_bob = Sas()
|
||||
|
||||
with pytest.raises(OlmSasError):
|
||||
sas_alice.calculate_mac(MESSAGE, EXTRA_INFO)
|
||||
|
||||
sas_alice.set_their_pubkey(sas_bob.pubkey)
|
||||
sas_bob.set_their_pubkey(sas_alice.pubkey)
|
||||
|
||||
alice_mac = sas_alice.calculate_mac(MESSAGE, EXTRA_INFO)
|
||||
bob_mac = sas_bob.calculate_mac(MESSAGE, EXTRA_INFO)
|
||||
|
||||
assert alice_mac == bob_mac
|
||||
|
||||
def test_cross_language_mac(self):
|
||||
"""Test MAC generating with a predefined key pair.
|
||||
|
||||
This test imports a private and public key from the C test and checks
|
||||
if we are getting the same MAC that the C code calculated.
|
||||
"""
|
||||
alice_private = [
|
||||
0x77, 0x07, 0x6D, 0x0A, 0x73, 0x18, 0xA5, 0x7D,
|
||||
0x3C, 0x16, 0xC1, 0x72, 0x51, 0xB2, 0x66, 0x45,
|
||||
0xDF, 0x4C, 0x2F, 0x87, 0xEB, 0xC0, 0x99, 0x2A,
|
||||
0xB1, 0x77, 0xFB, 0xA5, 0x1D, 0xB9, 0x2C, 0x2A
|
||||
]
|
||||
|
||||
bob_key = "3p7bfXt9wbTTW2HC7OQ1Nz+DQ8hbeGdNrfx+FG+IK08"
|
||||
message = "Hello world!"
|
||||
extra_info = "MAC"
|
||||
expected_mac = "2nSMTXM+TStTU3RUVTNSVVZUTlNWVlpVVGxOV1ZscFY"
|
||||
|
||||
sas_alice = Sas()
|
||||
sas_alice._create_sas(bytes(alice_private), 32)
|
||||
sas_alice.set_their_pubkey(bob_key)
|
||||
|
||||
alice_mac = sas_alice.calculate_mac(message, extra_info)
|
||||
|
||||
assert alice_mac == expected_mac
|
||||
|
||||
def test_long_mac_generating(self):
|
||||
sas_alice = Sas()
|
||||
sas_bob = Sas()
|
||||
|
||||
with pytest.raises(OlmSasError):
|
||||
sas_alice.calculate_mac_long_kdf(MESSAGE, EXTRA_INFO)
|
||||
|
||||
sas_alice.set_their_pubkey(sas_bob.pubkey)
|
||||
sas_bob.set_their_pubkey(sas_alice.pubkey)
|
||||
|
||||
alice_mac = sas_alice.calculate_mac_long_kdf(MESSAGE, EXTRA_INFO)
|
||||
bob_mac = sas_bob.calculate_mac_long_kdf(MESSAGE, EXTRA_INFO)
|
||||
bob_short_mac = sas_bob.calculate_mac(MESSAGE, EXTRA_INFO)
|
||||
|
||||
assert alice_mac == bob_mac
|
||||
assert alice_mac != bob_short_mac
|
||||
|
|
@ -0,0 +1,29 @@
|
|||
import base64
|
||||
import hashlib
|
||||
|
||||
from future.utils import bytes_to_native_str
|
||||
from hypothesis import given
|
||||
from hypothesis.strategies import text
|
||||
|
||||
from olm import sha256
|
||||
from olm._compat import to_bytes
|
||||
|
||||
|
||||
class TestClass(object):
|
||||
@given(text(), text())
|
||||
def test_sha256(self, input1, input2):
|
||||
first_hash = sha256(input1)
|
||||
second_hash = sha256(input2)
|
||||
|
||||
hashlib_hash = base64.b64encode(
|
||||
hashlib.sha256(to_bytes(input1)).digest()
|
||||
)
|
||||
|
||||
hashlib_hash = bytes_to_native_str(hashlib_hash[:-1])
|
||||
|
||||
if input1 == input2:
|
||||
assert first_hash == second_hash
|
||||
else:
|
||||
assert first_hash != second_hash
|
||||
|
||||
assert hashlib_hash == first_hash
|
||||
Loading…
Reference in New Issue