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 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 perform_pair_setup_part2(pin, ios_pairing_id, write_fun, salt,
server_public_key):
"""
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
:param write_fun: a function that takes a bytes representation of a TLV, the expected keys as list and returns
decoded TLV as list
: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.encode_list([
(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 = write_fun(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, ios_device_ltpk = ed25519.create_keypair()
# reversed:
# Pair-Setup-Encrypt-Salt instead of Pair-Setup-Controller-Sign-Salt
# Pair-Setup-Encrypt-Info instead of Pair-Setup-Controller-Sign-Info
hkdf_inst = hkdf.Hkdf('Pair-Setup-Controller-Sign-Salt'.encode(),
SrpClient.to_byte_array(session_key),
hash=hashlib.sha512)
ios_device_x = hkdf_inst.expand('Pair-Setup-Controller-Sign-Info'.encode(),
32)
hkdf_inst = hkdf.Hkdf('Pair-Setup-Encrypt-Salt'.encode(),
SrpClient.to_byte_array(session_key),
hash=hashlib.sha512)
session_key = hkdf_inst.expand('Pair-Setup-Encrypt-Info'.encode(), 32)
ios_device_pairing_id = ios_pairing_id.encode()
ios_device_info = ios_device_x + ios_device_pairing_id + ios_device_ltpk.to_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_ltpk.to_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)
tmp = bytearray(encrypted_data_with_auth_tag[0])
tmp += encrypted_data_with_auth_tag[1]
response_tlv = [(TLV.kTLVType_State, TLV.M5),
(TLV.kTLVType_EncryptedData, tmp)]
body = TLV.encode_list(response_tlv)
step6_expectations = [
TLV.kTLVType_State, TLV.kTLVType_Error, TLV.kTLVType_EncryptedData
]
response_tlv = write_fun(body, 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 homekit.exception.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]
hkdf_inst = hkdf.Hkdf('Pair-Setup-Accessory-Sign-Salt'.encode(),
SrpClient.to_byte_array(
srp_client.get_session_key()),
hash=hashlib.sha512)
accessory_x = hkdf_inst.expand('Pair-Setup-Accessory-Sign-Info'.encode(),
32)
accessory_info = accessory_x + accessory_pairing_id + accessory_ltpk
e25519s = ed25519.VerifyingKey(bytes(response_tlv[1][1]))
try:
e25519s.verify(bytes(accessory_sig), bytes(accessory_info))
except AssertionError:
raise InvalidSignatureError('step #7')
return {
'AccessoryPairingID': response_tlv[0][1].decode(),
'AccessoryLTPK': hexlify(response_tlv[1][1]).decode(),
'iOSPairingId': ios_pairing_id,
'iOSDeviceLTSK':
ios_device_ltsk.to_ascii(encoding='hex').decode()[:64],
'iOSDeviceLTPK': hexlify(ios_device_ltpk.to_bytes()).decode()
}