def test_separator_list(self):
val = [
[TLV.kTLVType_State, TLV.M3],
TLV.kTLVType_Separator_Pair,
[TLV.kTLVType_State, TLV.M4],
]
res = TLV.decode_bytearray(TLV.encode_list(val))
self.assertEqual(val, res)
def test_long_values_2(self):
val = [
[TLV.kTLVType_State, TLV.M3],
[TLV.kTLVType_Certificate, (150 * "a" + 150 * "b").encode()],
[TLV.kTLVType_Identifier, "hello".encode()],
]
res = TLV.decode_bytearray(TLV.encode_list(val))
self.assertEqual(val, res)
def test_long_values_decode_bytearray_to_list(self):
example = bytearray.fromhex("060103" + ("09FF" + 255 * "61" + "092D" +
45 * "61") + "010568656c6c6f")
expected = [
[6, bytearray(b"\x03")],
[9, bytearray(300 * b"a")],
[1, bytearray(b"hello")],
]
data = TLV.decode_bytearray(example)
self.assertListEqual(data, expected)
def perform_pair_setup_part2(
pin: str, ios_pairing_id: str, salt: bytearray,
server_public_key: bytearray
) -> Generator[Tuple[List[Tuple[int, bytearray]], List[int]], None, Dict[str,
str]]:
"""
Performs a pair setup operation as described in chapter 4.7 page 39 ff.
:param pin: the setup code from the accessory
:param ios_pairing_id: the id of the simulated ios device
:return: a dict with the ios device's part of the pairing information
:raises UnavailableError: if the device is already paired
:raises MaxTriesError: if the device received more than 100 unsuccessful pairing attempts
:raises BusyError: if a parallel pairing is ongoing
:raises AuthenticationError: if the verification of the device's SRP proof fails
:raises MaxPeersError: if the device cannot accept an additional pairing
:raises IllegalData: if the verification of the accessory's data fails
"""
srp_client = SrpClient("Pair-Setup", pin)
srp_client.set_salt(salt)
srp_client.set_server_public_key(server_public_key)
client_pub_key = srp_client.get_public_key()
client_proof = srp_client.get_proof()
response_tlv = [
(TLV.kTLVType_State, TLV.M3),
(TLV.kTLVType_PublicKey, SrpClient.to_byte_array(client_pub_key)),
(TLV.kTLVType_Proof, SrpClient.to_byte_array(client_proof)),
]
step4_expectations = [
TLV.kTLVType_State, TLV.kTLVType_Error, TLV.kTLVType_Proof
]
response_tlv = yield (response_tlv, step4_expectations)
#
# Step #5 ios --> accessory (Exchange Request) (see page 43)
#
logging.debug("#5 ios -> accessory: send SRP exchange request")
# M4 Verification (page 43)
response_tlv = TLV.reorder(response_tlv, step4_expectations)
assert (response_tlv[0][0] == TLV.kTLVType_State and response_tlv[0][1]
== TLV.M4), "perform_pair_setup: State not M4"
if response_tlv[1][0] == TLV.kTLVType_Error:
error_handler(response_tlv[1][1], "step 5")
assert response_tlv[1][
0] == TLV.kTLVType_Proof, "perform_pair_setup: Not a proof"
if not srp_client.verify_servers_proof(response_tlv[1][1]):
raise AuthenticationError("Step #5: wrong proof!")
# M5 Request generation (page 44)
session_key = srp_client.get_session_key()
ios_device_ltsk = ed25519.Ed25519PrivateKey.generate()
ios_device_ltpk = ios_device_ltsk.public_key()
ios_device_public_bytes = ios_device_ltpk.public_bytes(
encoding=serialization.Encoding.Raw,
format=serialization.PublicFormat.Raw)
# reversed:
# Pair-Setup-Encrypt-Salt instead of Pair-Setup-Controller-Sign-Salt
# Pair-Setup-Encrypt-Info instead of Pair-Setup-Controller-Sign-Info
ios_device_x = hkdf_derive(
SrpClient.to_byte_array(session_key),
"Pair-Setup-Controller-Sign-Salt",
"Pair-Setup-Controller-Sign-Info",
)
session_key = hkdf_derive(
SrpClient.to_byte_array(session_key),
"Pair-Setup-Encrypt-Salt",
"Pair-Setup-Encrypt-Info",
)
ios_device_pairing_id = ios_pairing_id.encode()
ios_device_info = ios_device_x + ios_device_pairing_id + ios_device_public_bytes
ios_device_signature = ios_device_ltsk.sign(ios_device_info)
sub_tlv = [
(TLV.kTLVType_Identifier, ios_device_pairing_id),
(TLV.kTLVType_PublicKey, ios_device_public_bytes),
(TLV.kTLVType_Signature, ios_device_signature),
]
sub_tlv_b = TLV.encode_list(sub_tlv)
# taking tge iOSDeviceX as key was reversed from
# https://github.com/KhaosT/HAP-NodeJS/blob/2ea9d761d9bd7593dd1949fec621ab085af5e567/lib/HAPServer.js
# function handlePairStepFive calling encryption.encryptAndSeal
encrypted_data_with_auth_tag = chacha20_aead_encrypt(
bytes(), session_key, "PS-Msg05".encode(), bytes([0, 0, 0, 0]),
sub_tlv_b)
response_tlv = [
(TLV.kTLVType_State, TLV.M5),
(TLV.kTLVType_EncryptedData, encrypted_data_with_auth_tag),
]
step6_expectations = [
TLV.kTLVType_State,
TLV.kTLVType_Error,
TLV.kTLVType_EncryptedData,
]
response_tlv = yield (response_tlv, step6_expectations)
#
# Step #7 ios (Verification) (page 47)
#
response_tlv = TLV.reorder(response_tlv, step6_expectations)
assert (response_tlv[0][0] == TLV.kTLVType_State and response_tlv[0][1]
== TLV.M6), "perform_pair_setup: State not M6"
if response_tlv[1][0] == TLV.kTLVType_Error:
error_handler(response_tlv[1][1], "step 7")
assert (response_tlv[1][0] == TLV.kTLVType_EncryptedData
), "perform_pair_setup: No encrypted data"
decrypted_data = chacha20_aead_decrypt(
bytes(),
session_key,
"PS-Msg06".encode(),
bytes([0, 0, 0, 0]),
response_tlv[1][1],
)
if decrypted_data is False:
raise IllegalData("step 7")
response_tlv = TLV.decode_bytearray(decrypted_data)
response_tlv = TLV.reorder(
response_tlv,
[
TLV.kTLVType_Identifier, TLV.kTLVType_PublicKey,
TLV.kTLVType_Signature
],
)
assert (response_tlv[2][0] == TLV.kTLVType_Signature
), "perform_pair_setup: No signature"
accessory_sig = response_tlv[2][1]
assert (response_tlv[0][0] == TLV.kTLVType_Identifier
), "perform_pair_setup: No identifier"
accessory_pairing_id = response_tlv[0][1]
assert (response_tlv[1][0] == TLV.kTLVType_PublicKey
), "perform_pair_setup: No public key"
accessory_ltpk = response_tlv[1][1]
accessory_x = hkdf_derive(
SrpClient.to_byte_array(srp_client.get_session_key()),
"Pair-Setup-Accessory-Sign-Salt",
"Pair-Setup-Accessory-Sign-Info",
)
accessory_info = accessory_x + accessory_pairing_id + accessory_ltpk
e25519s = ed25519.Ed25519PublicKey.from_public_bytes(
bytes(response_tlv[1][1]))
try:
e25519s.verify(bytes(accessory_sig), bytes(accessory_info))
except cryptography_exceptions.InvalidSignature:
raise InvalidSignatureError("step #7")
ios_device_ltsk_private_bytes = ios_device_ltsk.private_bytes(
encoding=serialization.Encoding.Raw,
format=serialization.PrivateFormat.Raw,
encryption_algorithm=serialization.NoEncryption(),
)
return {
"AccessoryPairingID": response_tlv[0][1].decode(),
"AccessoryLTPK": hexlify(response_tlv[1][1]).decode(),
"iOSPairingId": ios_pairing_id,
"iOSDeviceLTSK": ios_device_ltsk_private_bytes.hex(),
"iOSDeviceLTPK": ios_device_public_bytes.hex(),
}
