diff options
Diffstat (limited to 'freestyle_hid/_session.py')
| -rw-r--r-- | freestyle_hid/_session.py | 105 |
1 files changed, 83 insertions, 22 deletions
diff --git a/freestyle_hid/_session.py b/freestyle_hid/_session.py index 527a5fc..581f3fe 100644 --- a/freestyle_hid/_session.py +++ b/freestyle_hid/_session.py @@ -4,6 +4,7 @@ import csv import logging import pathlib +import random import re from typing import AnyStr, Callable, Iterator, Optional, Sequence, Tuple @@ -11,9 +12,15 @@ import construct from ._exceptions import ChecksumError, CommandError from ._hidwrapper import HidWrapper +from ._freestyle_encryption import SpeckEncrypt, SpeckCMAC ABBOTT_VENDOR_ID = 0x1A61 +_AUTH_ENC_MASTER_KEY = 0xdeadbeef +_AUTH_MAC_MASTER_KEY = 0xdeadbeef +_SESS_ENC_MASTER_KEY = 0xdeadbeef +_SESS_MAC_MASTER_KEY = 0xdeadbeef + _INIT_COMMAND = 0x01 _INIT_RESPONSE = 0x71 @@ -64,15 +71,6 @@ _FREESTYLE_MESSAGE = construct.Struct( ), ) -_FREESTYLE_ENCRYPTED_MESSAGE = construct.Struct( - hid_report=construct.Const(0, construct.Byte), - message_type=construct.Byte, - command=construct.Padded( - 63, # command can only be up to 62 bytes, but one is used for length. - construct.GreedyBytes, - ), -) - _TEXT_COMPLETION_RE = re.compile(b"CMD (?:OK|Fail!)") _TEXT_REPLY_FORMAT = re.compile( b"^(?P<message>.*)CKSM:(?P<checksum>[0-9A-F]{8})\r\n" @@ -121,12 +119,57 @@ class Session: encoding: str = "ascii", ) -> None: self._handle = HidWrapper.open(device_path, ABBOTT_VENDOR_ID, product_id) - self._text_message_type = text_message_type self._text_reply_message_type = text_reply_message_type self._encoding = encoding + self._encrypted_protocol = product_id in [0x3950] + + def encryption_handshake(self): + self.send_command(0x05, b"") + response = self.read_response() + assert response[0] == 0x06 + serial = response[1][:13] + + crypt = SpeckCMAC(_AUTH_ENC_MASTER_KEY) + auth_enc_key = crypt.derive("AuthrEnc".encode(), serial) + auth_enc = SpeckEncrypt(auth_enc_key) + crypt = SpeckCMAC(_AUTH_MAC_MASTER_KEY) + auth_mac_key = crypt.derive("AuthrMAC".encode(), serial) + auth_mac = SpeckCMAC(auth_mac_key) + + self.send_command(_ENCRYPTION_SETUP_COMMAND, b"\x11") + response = self.read_response() + assert response[0] == _ENCRYPTION_SETUP_RESPONSE + assert response[1][0] == 0x16 + reader_rand = response[1][1:9] + iv = int.from_bytes(response[1][9:16], 'big', signed=False) + driver_rand = random.randbytes(8) + resp_enc = auth_enc.encrypt(iv, reader_rand + driver_rand) + resp_mac = auth_mac.sign(b"\x14\x1a\x17" + resp_enc + b"\x01") + resp_mac = int.to_bytes(resp_mac, 8, byteorder='little', signed=False) + self.send_command(_ENCRYPTION_SETUP_COMMAND, b"\x17" + resp_enc + b"\x01" + resp_mac) + response = self.read_response() + assert response[0] == _ENCRYPTION_SETUP_RESPONSE + assert response[1][0] == 0x18 + mac = auth_mac.sign(b"\x33\x22" + response[1][:24]) + mac = int.to_bytes(mac, 8, byteorder='little', signed=False) + assert mac == response[1][24:32] + iv = int.from_bytes(response[1][17:24], 'big', signed=False) + resp_dec = auth_enc.decrypt(iv, response[1][1:17]) + assert resp_dec[:8] == driver_rand + assert resp_dec[8:] == reader_rand + + crypt = SpeckCMAC(_SESS_ENC_MASTER_KEY) + ses_enc_key = crypt.derive("SessnEnc".encode(), serial + reader_rand + driver_rand) + crypt = SpeckCMAC(_SESS_MAC_MASTER_KEY) + ses_mac_key = crypt.derive("SessnMAC".encode(), serial + reader_rand + driver_rand) + self.crypt_enc = SpeckEncrypt(ses_enc_key) + self.crypt_mac = SpeckCMAC(ses_mac_key) + #print("HANDSHAKE SUCCESSFUL!") def connect(self): + if self._encrypted_protocol: + self.encryption_handshake() """Open connection to the device, starting the knocking sequence.""" self.send_command(_INIT_COMMAND, b"") response = self.read_response() @@ -135,6 +178,26 @@ class Session: f"Connection error: unexpected message %{response[0]:02x}:{response[1].hex()}" ) + def encrypt_message(self, packet: bytes): + output = bytearray(packet) + # 0xFF IV is actually 0, because of some weird padding + encrypted = self.crypt_enc.encrypt(0xFF, packet[2:57]) + output[2:57] = encrypted + # Not giving a f**k about the IV counter for now + output[57:61] = bytes(4) + mac = self.crypt_mac.sign(output[1:61]) + output[61:65] = int.to_bytes(mac, 8, byteorder='little', signed=False)[4:] + return bytes(output) + + def decrypt_message(self, packet: bytes): + output = bytearray(packet) + mac = self.crypt_mac.sign(packet[:60]) + mac = int.to_bytes(mac, 8, byteorder='little', signed=False)[4:] + assert mac == packet[60:64] + iv = int.from_bytes(packet[56:60], 'big', signed=False) << 8 + output[1:56] = self.crypt_enc.decrypt(iv, packet[1:56]) + return bytes(output) + def send_command(self, message_type: int, command: bytes, encrypted: bool = False): """Send a raw command to the device. @@ -142,16 +205,14 @@ class Session: message_type: The first byte sent with the report to the device. command: The command to send out the device. """ - if encrypted: - assert message_type not in _ALWAYS_UNENCRYPTED_MESSAGES - meta_construct = _FREESTYLE_ENCRYPTED_MESSAGE - else: - meta_construct = _FREESTYLE_MESSAGE - usb_packet = meta_construct.build( + usb_packet = _FREESTYLE_MESSAGE.build( {"message_type": message_type, "command": command} ) + if self._encrypted_protocol and message_type not in _ALWAYS_UNENCRYPTED_MESSAGES: + usb_packet = self.encrypt_message(usb_packet) + logging.debug(f"Sending packet: {usb_packet!r}") self._handle.write(usb_packet) @@ -164,12 +225,12 @@ class Session: assert usb_packet message_type = usb_packet[0] - if not encrypted or message_type in _ALWAYS_UNENCRYPTED_MESSAGES: - message_length = usb_packet[1] - message_end_idx = 2 + message_length - message_content = usb_packet[2:message_end_idx] - else: - message_content = usb_packet[1:] + if self._encrypted_protocol and message_type not in _ALWAYS_UNENCRYPTED_MESSAGES: + usb_packet = self.decrypt_message(usb_packet) + + message_length = usb_packet[1] + message_end_idx = 2 + message_length + message_content = usb_packet[2:message_end_idx] # hidapi module returns a list of bytes rather than a bytes object. message = (message_type, bytes(message_content)) |