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Diffstat (limited to 'python/olm/utility.py')
| -rw-r--r-- | python/olm/utility.py | 132 |
1 files changed, 93 insertions, 39 deletions
diff --git a/python/olm/utility.py b/python/olm/utility.py index dac0225..0a64128 100644 --- a/python/olm/utility.py +++ b/python/olm/utility.py @@ -1,56 +1,110 @@ -from ._base import lib, c_void_p, c_size_t, c_char_p, \ - create_string_buffer, ERR, OlmError +# -*- 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 Utility module. -lib.olm_utility_size.argtypes = [] -lib.olm_utility_size.restype = c_size_t +This module contains utilities for olm. +It only contains the ed25519_verify function for signature verification. -lib.olm_utility.argtypes = [c_void_p] -lib.olm_utility.restype = c_void_p +Examples: + >>> alice = Account() -lib.olm_utility_last_error.argtypes = [c_void_p] -lib.olm_utility_last_error.restype = c_char_p + >>> message = "Test" + >>> signature = alice.sign(message) + >>> signing_key = alice.identity_keys["ed25519"] + >>> ed25519_verify(signing_key, message, signature) -def utility_errcheck(res, func, args): - if res == ERR: - raise OlmError("%s: %s" % ( - func.__name__, lib.olm_utility_last_error(args[0]) - )) - return res +""" +# pylint: disable=redefined-builtin,unused-import +from typing import AnyStr, Type -def utility_function(func, *types): - func.argtypes = (c_void_p,) + types - func.restypes = c_size_t - func.errcheck = utility_errcheck +# pylint: disable=no-name-in-module +from _libolm import ffi, lib # type: ignore -utility_function( - lib.olm_ed25519_verify, - c_void_p, c_size_t, # key, key_length - c_void_p, c_size_t, # message, message_length - c_void_p, c_size_t, # signature, signature_length -) +from ._compat import to_bytearray, to_bytes +from ._finalize import track_for_finalization -class Utility(object): - def __init__(self): - self.buf = create_string_buffer(lib.olm_utility_size()) - self.ptr = lib.olm_utility(self.buf) +def _clear_utility(utility): # pragma: no cover + # type: (ffi.cdata) -> None + lib.olm_clear_utility(utility) -_utility = None + +class OlmVerifyError(Exception): + """libolm signature verification exception.""" + + +class _Utility(object): + # pylint: disable=too-few-public-methods + """libolm Utility class.""" + + _buf = None + _utility = None + + @classmethod + def _allocate(cls): + # type: (Type[_Utility]) -> None + cls._buf = ffi.new("char[]", lib.olm_utility_size()) + cls._utility = lib.olm_utility(cls._buf) + track_for_finalization(cls, cls._utility, _clear_utility) + + @classmethod + def _check_error(cls, ret): + # type: (int) -> None + if ret != lib.olm_error(): + return + + raise OlmVerifyError("{}".format( + ffi.string(lib.olm_utility_last_error( + cls._utility)).decode("utf-8"))) + + @classmethod + def _ed25519_verify(cls, key, message, signature): + # type: (Type[_Utility], AnyStr, AnyStr, AnyStr) -> None + if not cls._utility: + cls._allocate() + + byte_key = to_bytes(key) + byte_message = to_bytearray(message) + byte_signature = to_bytes(signature) + + try: + cls._check_error( + lib.olm_ed25519_verify(cls._utility, byte_key, len(byte_key), + ffi.from_buffer(byte_message), + len(byte_message), + byte_signature, len(byte_signature))) + 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 def ed25519_verify(key, message, signature): - """ Verify an ed25519 signature. Raises an OlmError if verification fails. + # type: (AnyStr, AnyStr, AnyStr) -> None + """Verify an ed25519 signature. + + Raises an OlmVerifyError if verification fails. + Args: - key(bytes): The ed25519 public key used for signing. - message(bytes): The signed message. + key(str): The ed25519 public key used for signing. + message(str): The signed message. signature(bytes): The message signature. """ - global _utility - if not _utility: - _utility = Utility() - lib.olm_ed25519_verify(_utility.ptr, - key, len(key), - message, len(message), - signature, len(signature)) + return _Utility._ed25519_verify(key, message, signature) |