diff options
| -rw-r--r-- | python/Makefile | 2 | ||||
| -rw-r--r-- | python/olm/_compat.py | 10 | ||||
| -rw-r--r-- | python/olm/account.py | 62 | ||||
| -rw-r--r-- | python/olm/group_session.py | 165 | ||||
| -rw-r--r-- | python/olm/session.py | 106 | ||||
| -rw-r--r-- | python/olm/utility.py | 19 |
6 files changed, 236 insertions, 128 deletions
diff --git a/python/Makefile b/python/Makefile index a19c4f8..5da703a 100644 --- a/python/Makefile +++ b/python/Makefile @@ -3,6 +3,8 @@ all: olm-python2 olm-python3 include/olm/olm.h: ../include/olm/olm.h ../include/olm/inbound_group_session.h ../include/olm/outbound_group_session.h mkdir -p include/olm $(CPP) -I dummy -I ../include ../include/olm/olm.h -o include/olm/olm.h +# add memset to the header so that we can use it to clear buffers + echo 'void *memset(void *s, int c, size_t n);' >> include/olm/olm.h olm-python2: include/olm/olm.h DEVELOP=$(DEVELOP) python2 setup.py build diff --git a/python/olm/_compat.py b/python/olm/_compat.py index 8f1670d..91e4d1b 100644 --- a/python/olm/_compat.py +++ b/python/olm/_compat.py @@ -26,6 +26,16 @@ except ImportError: # pragma: no cover URANDOM = urandom # type: ignore +def to_bytearray(string): + # type: (AnyStr) -> bytes + if isinstance(string, bytes): + return bytearray(string) + elif isinstance(string, str): + return bytearray(string, "utf-8") + + raise TypeError("Invalid type {}".format(type(string))) + + def to_bytes(string): # type: (AnyStr) -> bytes if isinstance(string, bytes): diff --git a/python/olm/account.py b/python/olm/account.py index 1dba96d..8455655 100644 --- a/python/olm/account.py +++ b/python/olm/account.py @@ -37,7 +37,7 @@ 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 ._compat import URANDOM, to_bytearray from ._finalize import track_for_finalization # This is imported only for type checking purposes @@ -82,12 +82,12 @@ class Account(object): 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, + lib.olm_create_account(self._account, ffi.from_buffer(random), random_length)) + def _check_error(self, ret): # type: (int) -> None if ret != lib.olm_error(): @@ -111,15 +111,23 @@ class Account(object): 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) + byte_key = bytearray(passphrase, "utf-8") if passphrase else b"" 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)) + try: + self._check_error( + lib.olm_pickle_account(self._account, + ffi.from_buffer(byte_key), + len(byte_key), + pickle_buffer, + pickle_length)) + finally: + # zero out copies of the passphrase + for i in range(0, len(byte_key)): + byte_key[i] = 0 + return ffi.unpack(pickle_buffer, pickle_length) @classmethod @@ -143,15 +151,22 @@ class Account(object): 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) + byte_key = bytearray(passphrase, "utf-8") if passphrase else b"" + # copy because unpickle will destroy the buffer 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) + try: + ret = lib.olm_unpickle_account(obj._account, + ffi.from_buffer(byte_key), + len(byte_key), + pickle_buffer, + len(pickle)) + obj._check_error(ret) + finally: + for i in range(0, len(byte_key)): + byte_key[i] = 0 return obj @@ -178,14 +193,21 @@ class Account(object): Args: message(str): The message to sign. """ - bytes_message = to_bytes(message) + bytes_message = to_bytearray(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)) + try: + self._check_error( + lib.olm_account_sign(self._account, + ffi.from_buffer(bytes_message), + len(bytes_message), out_buffer, + out_length)) + finally: + # clear out copies of the message, which may be plaintext + if bytes_message is not message: + for i in range(0, len(bytes_message)): + bytes_message[i] = 0 return bytes_to_native_str(ffi.unpack(out_buffer, out_length)) @@ -214,10 +236,10 @@ class Account(object): 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)) + self._account, count, ffi.from_buffer(random), random_length)) @property def one_time_keys(self): diff --git a/python/olm/group_session.py b/python/olm/group_session.py index bbb5e56..814ce27 100644 --- a/python/olm/group_session.py +++ b/python/olm/group_session.py @@ -33,7 +33,7 @@ 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 ._compat import URANDOM, to_bytearray, to_bytes from ._finalize import track_for_finalization @@ -78,12 +78,17 @@ class InboundGroupSession(object): if False: # pragma: no cover self._session = self._session # type: ffi.cdata - byte_session_key = to_bytes(session_key) - - key_buffer = ffi.new("char[]", byte_session_key) - ret = lib.olm_init_inbound_group_session( - self._session, key_buffer, len(byte_session_key) - ) + byte_session_key = to_bytearray(session_key) + + try: + ret = lib.olm_init_inbound_group_session( + self._session, + ffi.from_buffer(byte_session_key), len(byte_session_key) + ) + finally: + if byte_session_key is not session_key: + for i in range(0, len(byte_session_key)): + byte_session_key[i] = 0 self._check_error(ret) def pickle(self, passphrase=""): @@ -98,19 +103,23 @@ class InboundGroupSession(object): passphrase(str, optional): The passphrase to be used to encrypt the session. """ - byte_passphrase = bytes(passphrase, "utf-8") if passphrase else b"" + byte_passphrase = bytearray(passphrase, "utf-8") if passphrase else b"" - passphrase_buffer = ffi.new("char[]", byte_passphrase) pickle_length = lib.olm_pickle_inbound_group_session_length( self._session) pickle_buffer = ffi.new("char[]", pickle_length) - ret = lib.olm_pickle_inbound_group_session( - self._session, passphrase_buffer, len(byte_passphrase), - pickle_buffer, pickle_length - ) - - self._check_error(ret) + try: + ret = lib.olm_pickle_inbound_group_session( + self._session, + ffi.from_buffer(byte_passphrase), len(byte_passphrase), + pickle_buffer, pickle_length + ) + self._check_error(ret) + finally: + # clear out copies of the passphrase + for i in range(0, len(byte_passphrase)): + byte_passphrase[i] = 0 return ffi.unpack(pickle_buffer, pickle_length) @@ -135,20 +144,25 @@ class InboundGroupSession(object): if not pickle: raise ValueError("Pickle can't be empty") - byte_passphrase = bytes(passphrase, "utf-8") if passphrase else b"" - passphrase_buffer = ffi.new("char[]", byte_passphrase) + byte_passphrase = bytearray(passphrase, "utf-8") if passphrase else b"" + # copy because unpickle will destroy the buffer pickle_buffer = ffi.new("char[]", pickle) obj = cls.__new__(cls) - ret = lib.olm_unpickle_inbound_group_session( - obj._session, - passphrase_buffer, - len(byte_passphrase), - pickle_buffer, - len(pickle) - ) - obj._check_error(ret) + try: + ret = lib.olm_unpickle_inbound_group_session( + obj._session, + ffi.from_buffer(byte_passphrase), + len(byte_passphrase), + pickle_buffer, + len(pickle) + ) + obj._check_error(ret) + finally: + # clear out copies of the passphrase + for i in range(0, len(byte_passphrase)): + byte_passphrase[i] = 0 return obj @@ -189,12 +203,15 @@ class InboundGroupSession(object): byte_ciphertext = to_bytes(ciphertext) + # copy because max_plaintext_length will destroy the buffer ciphertext_buffer = ffi.new("char[]", byte_ciphertext) max_plaintext_length = lib.olm_group_decrypt_max_plaintext_length( self._session, ciphertext_buffer, len(byte_ciphertext) ) + self._check_error(max_plaintext_length) plaintext_buffer = ffi.new("char[]", max_plaintext_length) + # copy because max_plaintext_length will destroy the buffer ciphertext_buffer = ffi.new("char[]", byte_ciphertext) message_index = ffi.new("uint32_t*") @@ -206,10 +223,15 @@ class InboundGroupSession(object): self._check_error(plaintext_length) - return bytes_to_native_str(ffi.unpack( + plaintext = bytes_to_native_str(ffi.unpack( plaintext_buffer, plaintext_length - )), message_index[0] + )) + + # clear out copies of the plaintext + lib.memset(plaintext_buffer, 0, max_plaintext_length) + + return plaintext, message_index[0] @property def id(self): @@ -281,15 +303,19 @@ class InboundGroupSession(object): """ obj = cls.__new__(cls) - byte_session_key = to_bytes(session_key) + byte_session_key = to_bytearray(session_key) - key_buffer = ffi.new("char[]", byte_session_key) - ret = lib.olm_import_inbound_group_session( - obj._session, - key_buffer, - len(byte_session_key) - ) - obj._check_error(ret) + try: + ret = lib.olm_import_inbound_group_session( + obj._session, + ffi.from_buffer(byte_session_key), + len(byte_session_key) + ) + obj._check_error(ret) + finally: + if byte_session_key is not session_key: + for i in range(0, len(byte_session_key)): + byte_session_key[i] = 0 return obj @@ -323,10 +349,9 @@ class OutboundGroupSession(object): self._session ) random = URANDOM(random_length) - random_buffer = ffi.new("char[]", random) ret = lib.olm_init_outbound_group_session( - self._session, random_buffer, random_length + self._session, ffi.from_buffer(random), random_length ) self._check_error(ret) @@ -353,17 +378,23 @@ class OutboundGroupSession(object): passphrase(str, optional): The passphrase to be used to encrypt the session. """ - byte_passphrase = bytes(passphrase, "utf-8") if passphrase else b"" - passphrase_buffer = ffi.new("char[]", byte_passphrase) + byte_passphrase = bytearray(passphrase, "utf-8") if passphrase else b"" pickle_length = lib.olm_pickle_outbound_group_session_length( self._session) pickle_buffer = ffi.new("char[]", pickle_length) - ret = lib.olm_pickle_outbound_group_session( - self._session, passphrase_buffer, len(byte_passphrase), - pickle_buffer, pickle_length - ) - self._check_error(ret) + try: + ret = lib.olm_pickle_outbound_group_session( + self._session, + ffi.from_buffer(byte_passphrase), len(byte_passphrase), + pickle_buffer, pickle_length + ) + self._check_error(ret) + finally: + # clear out copies of the passphrase + for i in range(0, len(byte_passphrase)): + byte_passphrase[i] = 0 + return ffi.unpack(pickle_buffer, pickle_length) @classmethod @@ -387,20 +418,25 @@ class OutboundGroupSession(object): if not pickle: raise ValueError("Pickle can't be empty") - byte_passphrase = bytes(passphrase, "utf-8") if passphrase else b"" - passphrase_buffer = ffi.new("char[]", byte_passphrase) + byte_passphrase = bytearray(passphrase, "utf-8") if passphrase else b"" + # copy because unpickle will destroy the buffer pickle_buffer = ffi.new("char[]", pickle) obj = cls.__new__(cls) - ret = lib.olm_unpickle_outbound_group_session( - obj._session, - passphrase_buffer, - len(byte_passphrase), - pickle_buffer, - len(pickle) - ) - obj._check_error(ret) + try: + ret = lib.olm_unpickle_outbound_group_session( + obj._session, + ffi.from_buffer(byte_passphrase), + len(byte_passphrase), + pickle_buffer, + len(pickle) + ) + obj._check_error(ret) + finally: + # clear out copies of the passphrase + for i in range(0, len(byte_passphrase)): + byte_passphrase[i] = 0 return obj @@ -414,21 +450,26 @@ class OutboundGroupSession(object): plaintext(str): A string that will be encrypted using the group session. """ - byte_plaintext = to_bytes(plaintext) + byte_plaintext = to_bytearray(plaintext) message_length = lib.olm_group_encrypt_message_length( self._session, len(byte_plaintext) ) message_buffer = ffi.new("char[]", message_length) - plaintext_buffer = ffi.new("char[]", byte_plaintext) + try: + ret = lib.olm_group_encrypt( + self._session, + ffi.from_buffer(byte_plaintext), len(byte_plaintext), + message_buffer, message_length, + ) + self._check_error(ret) + finally: + # clear out copies of plaintext + if byte_plaintext is not plaintext: + for i in range(0, len(byte_plaintext)): + byte_plaintext[i] = 0 - ret = lib.olm_group_encrypt( - self._session, - plaintext_buffer, len(byte_plaintext), - message_buffer, message_length, - ) - self._check_error(ret) return bytes_to_native_str(ffi.unpack(message_buffer, message_length)) @property diff --git a/python/olm/session.py b/python/olm/session.py index b123e8a..cba9be0 100644 --- a/python/olm/session.py +++ b/python/olm/session.py @@ -40,7 +40,7 @@ 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 ._compat import URANDOM, to_bytearray, to_bytes from ._finalize import track_for_finalization # This is imported only for type checking purposes @@ -164,15 +164,22 @@ class Session(object): passphrase(str, optional): The passphrase to be used to encrypt the session. """ - byte_key = bytes(passphrase, "utf-8") if passphrase else b"" - key_buffer = ffi.new("char[]", byte_key) + byte_key = bytearray(passphrase, "utf-8") if passphrase else b"" pickle_length = lib.olm_pickle_session_length(self._session) pickle_buffer = ffi.new("char[]", pickle_length) - self._check_error( - lib.olm_pickle_session(self._session, key_buffer, len(byte_key), - pickle_buffer, pickle_length)) + try: + self._check_error( + lib.olm_pickle_session(self._session, + ffi.from_buffer(byte_key), + len(byte_key), + pickle_buffer, pickle_length)) + finally: + # clear out copies of the passphrase + for i in range(0, len(byte_key)): + byte_key[i] = 0 + return ffi.unpack(pickle_buffer, pickle_length) @classmethod @@ -196,16 +203,23 @@ class Session(object): 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) + byte_key = bytearray(passphrase, "utf-8") if passphrase else b"" + # copy because unpickle will destroy the buffer pickle_buffer = ffi.new("char[]", pickle) session = cls.__new__(cls) - ret = lib.olm_unpickle_session(session._session, key_buffer, - len(byte_key), pickle_buffer, - len(pickle)) - session._check_error(ret) + try: + ret = lib.olm_unpickle_session(session._session, + ffi.from_buffer(byte_key), + len(byte_key), + pickle_buffer, + len(pickle)) + session._check_error(ret) + finally: + # clear out copies of the passphrase + for i in range(0, len(byte_key)): + byte_key[i] = 0 return session @@ -217,29 +231,32 @@ class Session(object): Args: plaintext(str): The plaintext message that will be encrypted. """ - byte_plaintext = to_bytes(plaintext) + byte_plaintext = to_bytearray(plaintext) r_length = lib.olm_encrypt_random_length(self._session) random = URANDOM(r_length) - random_buffer = ffi.new("char[]", random) - message_type = lib.olm_encrypt_message_type(self._session) + try: + message_type = lib.olm_encrypt_message_type(self._session) - self._check_error(message_type) - - ciphertext_length = lib.olm_encrypt_message_length( - self._session, len(plaintext) - ) - ciphertext_buffer = ffi.new("char[]", ciphertext_length) + self._check_error(message_type) - plaintext_buffer = ffi.new("char[]", byte_plaintext) + ciphertext_length = lib.olm_encrypt_message_length( + self._session, len(byte_plaintext) + ) + ciphertext_buffer = ffi.new("char[]", ciphertext_length) - self._check_error(lib.olm_encrypt( - self._session, - plaintext_buffer, len(byte_plaintext), - random_buffer, r_length, - ciphertext_buffer, ciphertext_length, - )) + self._check_error(lib.olm_encrypt( + self._session, + ffi.from_buffer(byte_plaintext), len(byte_plaintext), + ffi.from_buffer(random), r_length, + ciphertext_buffer, ciphertext_length, + )) + finally: + # clear out copies of plaintext + if byte_plaintext is not plaintext: + for i in range(0, len(byte_plaintext)): + byte_plaintext[i] = 0 if message_type == lib.OLM_MESSAGE_TYPE_PRE_KEY: return OlmPreKeyMessage( @@ -274,22 +291,34 @@ class Session(object): raise ValueError("Ciphertext can't be empty") byte_ciphertext = to_bytes(message.ciphertext) + # make a copy the ciphertext buffer, because + # olm_decrypt_max_plaintext_length wants to destroy something ciphertext_buffer = ffi.new("char[]", byte_ciphertext) max_plaintext_length = lib.olm_decrypt_max_plaintext_length( self._session, message.message_type, ciphertext_buffer, len(byte_ciphertext) ) + self._check_error(max_plaintext_length) plaintext_buffer = ffi.new("char[]", max_plaintext_length) + + # make a copy the ciphertext buffer, because + # olm_decrypt_max_plaintext_length wants to destroy something ciphertext_buffer = ffi.new("char[]", byte_ciphertext) plaintext_length = lib.olm_decrypt( - self._session, message.message_type, ciphertext_buffer, - len(byte_ciphertext), plaintext_buffer, max_plaintext_length + self._session, message.message_type, + ciphertext_buffer, len(byte_ciphertext), + plaintext_buffer, max_plaintext_length ) self._check_error(plaintext_length) - return bytes_to_native_str( + plaintext = bytes_to_native_str( ffi.unpack(plaintext_buffer, plaintext_length)) + # clear out copies of the plaintext + lib.memset(plaintext_buffer, 0, max_plaintext_length) + + return plaintext + @property def id(self): # type: () -> str @@ -331,16 +360,16 @@ class Session(object): ret = None byte_ciphertext = to_bytes(message.ciphertext) - + # make a copy, because olm_matches_inbound_session(_from) will distroy + # it message_buffer = ffi.new("char[]", byte_ciphertext) if identity_key: byte_id_key = to_bytes(identity_key) - identity_key_buffer = ffi.new("char[]", byte_id_key) ret = lib.olm_matches_inbound_session_from( self._session, - identity_key_buffer, len(byte_id_key), + ffi.from_buffer(byte_id_key), len(byte_id_key), message_buffer, len(byte_ciphertext) ) @@ -447,14 +476,11 @@ class OutboundSession(Session): self._session) random = URANDOM(session_random_length) - random_buffer = ffi.new("char[]", random) - identity_key_buffer = ffi.new("char[]", byte_id_key) - one_time_key_buffer = ffi.new("char[]", byte_one_time) self._check_error(lib.olm_create_outbound_session( self._session, account._account, - identity_key_buffer, len(byte_id_key), - one_time_key_buffer, len(byte_one_time), - random_buffer, session_random_length + ffi.from_buffer(byte_id_key), len(byte_id_key), + ffi.from_buffer(byte_one_time), len(byte_one_time), + ffi.from_buffer(random), session_random_length )) diff --git a/python/olm/utility.py b/python/olm/utility.py index 1c5c41d..0a64128 100644 --- a/python/olm/utility.py +++ b/python/olm/utility.py @@ -36,7 +36,7 @@ from typing import AnyStr, Type # pylint: disable=no-name-in-module from _libolm import ffi, lib # type: ignore -from ._compat import to_bytes +from ._compat import to_bytearray, to_bytes from ._finalize import track_for_finalization @@ -80,13 +80,20 @@ class _Utility(object): cls._allocate() byte_key = to_bytes(key) - byte_message = to_bytes(message) + byte_message = to_bytearray(message) byte_signature = to_bytes(signature) - cls._check_error( - lib.olm_ed25519_verify(cls._utility, byte_key, len(byte_key), - byte_message, len(byte_message), - byte_signature, len(byte_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): |