diff options
| -rw-r--r-- | freestyle_hid/_freestyle_encryption.py | 67 | ||||
| -rw-r--r-- | freestyle_hid/_session.py | 48 |
2 files changed, 75 insertions, 40 deletions
diff --git a/freestyle_hid/_freestyle_encryption.py b/freestyle_hid/_freestyle_encryption.py index 0461cb8..a0268eb 100644 --- a/freestyle_hid/_freestyle_encryption.py +++ b/freestyle_hid/_freestyle_encryption.py @@ -6,7 +6,7 @@ class SpeckEncrypt: def __init__(self, key): # Perform key expansion and store the round keys - self.key = key & ((2 ** 128) - 1) + self.key = key & ((2**128) - 1) self.key_schedule = [self.key & 0xFFFFFFFF] key_buf = [(self.key >> (x * 32)) & 0xFFFFFFFF for x in range(1, 4)] for x in range(26): @@ -58,13 +58,19 @@ class SpeckEncrypt: def encrypt(self, iv, plain): plain = bytearray(plain) input_length = len(plain) - plain.extend(bytes(b'\x00' * (8 - (input_length % 8)))) - iv = int.from_bytes(iv.to_bytes(8, byteorder='big'), byteorder='little', signed=False) + plain.extend(bytes(b"\x00" * (8 - (input_length % 8)))) + iv = int.from_bytes( + iv.to_bytes(8, byteorder="big"), byteorder="little", signed=False + ) output = bytearray() for i in range(len(plain) // 8): k = self.encrypt_block(iv) - res = k ^ int.from_bytes(plain[i*8:i*8+8], byteorder='little', signed=False) - output.extend(int.to_bytes(res, 8, byteorder='little', signed=False)) + slice_start = i * 8 + slice_end = slice_start + 8 + res = k ^ int.from_bytes( + plain[slice_start:slice_end], byteorder="little", signed=False + ) + output.extend(int.to_bytes(res, 8, byteorder="little", signed=False)) iv += 1 encrypted = output[:input_length] return bytes(encrypted) @@ -72,24 +78,30 @@ class SpeckEncrypt: def decrypt(self, iv, encrypted): return self.encrypt(iv, encrypted) -class SpeckCMAC: +class SpeckCMAC: def __init__(self, key): self.cipher = SpeckEncrypt(key) k0 = self.cipher.encrypt_block(0) - k0 = int.from_bytes(k0.to_bytes(8, byteorder='big'), byteorder='little', signed=False) + k0 = int.from_bytes( + k0.to_bytes(8, byteorder="big"), byteorder="little", signed=False + ) - k1 = (k0 << 1) & 0XFFFFFFFFFFFFFFFF - if (k0 >> 63 != 0): + k1 = (k0 << 1) & 0xFFFFFFFFFFFFFFFF + if k0 >> 63 != 0: k1 ^= 0x1B - k2 = (k1 << 1) & 0XFFFFFFFFFFFFFFFF - if (k1 >> 63 != 0): + k2 = (k1 << 1) & 0xFFFFFFFFFFFFFFFF + if k1 >> 63 != 0: k2 ^= 0x1B - k1 = int.from_bytes(k1.to_bytes(8, byteorder='big'), byteorder='little', signed=False) - k2 = int.from_bytes(k2.to_bytes(8, byteorder='big'), byteorder='little', signed=False) + k1 = int.from_bytes( + k1.to_bytes(8, byteorder="big"), byteorder="little", signed=False + ) + k2 = int.from_bytes( + k2.to_bytes(8, byteorder="big"), byteorder="little", signed=False + ) self.k1 = k1 self.k2 = k2 @@ -98,22 +110,33 @@ class SpeckCMAC: i = 0 data_len = len(data) - while (i < data_len): + while i < data_len: data_left = data_len - i - if (data_left == 8): - block = int.from_bytes(data[i:i+8], 'little') ^ self.k1 - elif (data_left < 8): - block = int.from_bytes(data[i:i+data_left] + b'\x80' + b'\x00'*(7-data_left), 'little') ^ self.k2 + slice_start = i + slice_end = slice_start + 8 + if data_left == 8: + block = int.from_bytes(data[slice_start:slice_end], "little") ^ self.k1 + elif data_left < 8: + slice_end = i + data_left + block = ( + int.from_bytes( + data[slice_start:slice_end] + + b"\x80" + + b"\x00" * (7 - data_left), + "little", + ) + ^ self.k2 + ) else: - block = int.from_bytes(data[i:i+8], 'little') + block = int.from_bytes(data[slice_start:slice_end], "little") c = self.cipher.encrypt_block(c ^ block) i += 8 return c def derive(self, label, context): - data = label + b'\x00' + context + b'\x80\x00' - d1 = self.sign(b'\x01' + data) - d2 = self.sign(b'\x02' + data) << 64 + data = label + b"\x00" + context + b"\x80\x00" + d1 = self.sign(b"\x01" + data) + d2 = self.sign(b"\x02" + data) << 64 return d1 | d2 diff --git a/freestyle_hid/_session.py b/freestyle_hid/_session.py index 581f3fe..cdfca42 100644 --- a/freestyle_hid/_session.py +++ b/freestyle_hid/_session.py @@ -11,15 +11,15 @@ from typing import AnyStr, Callable, Iterator, Optional, Sequence, Tuple import construct from ._exceptions import ChecksumError, CommandError +from ._freestyle_encryption import SpeckCMAC, SpeckEncrypt 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 +_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 @@ -142,30 +142,36 @@ class Session: 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) + 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) + 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) + 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) + 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) + 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) + 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!") + # print("HANDSHAKE SUCCESSFUL!") def connect(self): if self._encrypted_protocol: @@ -186,15 +192,15 @@ class Session: # 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:] + 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:] + 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 + 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) @@ -210,7 +216,10 @@ class Session: {"message_type": message_type, "command": command} ) - if self._encrypted_protocol and message_type not in _ALWAYS_UNENCRYPTED_MESSAGES: + 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}") @@ -225,7 +234,10 @@ class Session: assert usb_packet message_type = usb_packet[0] - if self._encrypted_protocol and message_type not in _ALWAYS_UNENCRYPTED_MESSAGES: + if ( + self._encrypted_protocol + and message_type not in _ALWAYS_UNENCRYPTED_MESSAGES + ): usb_packet = self.decrypt_message(usb_packet) message_length = usb_packet[1] |