def get_session_data(username, password_verifier, salt, client_public, private,
preset):
"""Print out server session data."""
session = SRPServerSession(SRPContext(username,
prime=preset[0],
generator=preset[1]),
hex_from_b64(password_verifier),
private=private)
session.process(client_public, salt, base64=True)
click.secho('Server session key: %s' % session.key_b64)
click.secho('Server session key proof: %s' % session.key_proof_b64)
click.secho('Server session key hash: %s' % session.key_proof_hash_b64)
def new_server_session(keys, pin):
"""Create SRP server session."""
context = SRPContext(
"Pair-Setup",
str(pin),
prime=constants.PRIME_3072,
generator=constants.PRIME_3072_GEN,
hash_func=hashlib.sha512,
bits_salt=128,
bits_random=512,
)
username, verifier, salt = context.get_user_data_triplet()
context_server = SRPContext(
username,
prime=constants.PRIME_3072,
generator=constants.PRIME_3072_GEN,
hash_func=hashlib.sha512,
bits_salt=128,
bits_random=512,
)
session = SRPServerSession(
context_server, verifier, binascii.hexlify(keys.auth).decode()
)
return session, salt
def __init__(self, loop, credentials, atv_device_id):
"""Initialize a new instance of ProxyMrpAppleTV."""
self.loop = loop
self.credentials = credentials
self.atv_device_id = atv_device_id
self.server = None
self.buffer = b''
self.has_paired = False
self.transport = None
self.chacha = None
self.connection = None
self.input_key = None
self.output_key = None
self.mapping = {
protobuf.DEVICE_INFO_MESSAGE: self.handle_device_info,
protobuf.CRYPTO_PAIRING_MESSAGE: self.handle_crypto_pairing,
}
self._shared = None
self._session_key = None
self._signing_key = SigningKey(32 * b'\x01')
self._auth_private = self._signing_key.to_seed()
self._auth_public = self._signing_key.get_verifying_key().to_bytes()
self._verify_private = curve25519.Private(secret=32 * b'\x01')
self._verify_public = self._verify_private.get_public()
self.context = SRPContext('Pair-Setup',
str(1111),
prime=constants.PRIME_3072,
generator=constants.PRIME_3072_GEN,
hash_func=hashlib.sha512,
bits_salt=128)
self.username, self.verifier, self.salt = \
self.context.get_user_data_triplet()
context_server = SRPContext('Pair-Setup',
prime=constants.PRIME_3072,
generator=constants.PRIME_3072_GEN,
hash_func=hashlib.sha512,
bits_salt=128)
self._session = SRPServerSession(
context_server, self.verifier,
binascii.hexlify(self._auth_private).decode())
def get_private_and_public(username, password_verifier, private, preset):
"""Print out server public and private."""
session = SRPServerSession(SRPContext(username,
prime=preset[0],
generator=preset[1]),
hex_from_b64(password_verifier),
private=private)
click.secho('Server private: %s' % session.private_b64)
click.secho('Server public: %s' % session.public_b64)
### at the client, where the password is known srp_context = SRPContext(username, password) # gen, prime user, password_verifier, salt = srp_context.get_user_data_triplet() gen = srp_context.generator prime = srp_context.prime ##### # HERE WE ARE IN THE SERVER # client send the server user, password_verifier, salt, gen, prime server_context = SRPContext(username, prime=prime, generator=gen) ########### # authentication starts here server_session = SRPServerSession(server_context, password_verifier) server_public_B = server_session.public # to be sent to the client ##### # HERE WE ARE IN THE CLIENT client_session = SRPClientSession(srp_context) client_public_A = client_session.public # the client has received B # the server has received A ##### # HERE WE ARE IN THE SERVER server_session.process(client_public_A, salt) # generating the common secret
print('A new padding test requested by ' + addr[0] + ':' + str(addr[1]))
#this should be done offline, only once, the server should store somewhere these data
context = SRPContext(USERNAME, PASSWORD)
username, password_verifier, server_salt = context.get_user_data_triplet()
print(username)
print(password_verifier)
print(server_salt)
prime = context.prime
gen = context.generator
print(prime)
print(gen)
# generate user-based server parameters
server_session = SRPServerSession(
SRPContext(username, prime=prime, generator=gen), password_verifier)
server_public_B = server_session.public
print(server_public_B)
server_data = json.dumps({
'prime': prime,
'generator': gen,
'B': server_public_B,
'server_salt': server_salt
})
print(server_data)
conn.send(server_data.encode())
# receive client parameters
user_data = conn.recv(DATA_SIZE).decode()
password_verifier = value_encode(
context.get_common_password_verifier(
context.get_common_password_hash(unhexlify(salt))))
else:
_, password_verifier, salt = context.get_user_data_triplet()
print("v:", password_verifier)
# Client => Server: username, A
sys.stdout.write("A: ")
sys.stdout.flush()
A = input()
# Receive username from client and generate server public.
server_session = SRPServerSession(context,
password_verifier,
private=args.private)
print("b:", server_session.private)
# Server => Client: s, B
print("s:", salt)
print("B:", server_session.public)
# Client => Server: M
sys.stdout.write("M: ")
sys.stdout.flush()
M = input()
# Process client public and verify session key proof.
server_session.process(A, salt)
# print(prime)
# print(gen)
# receive user data
user_data = conn.recv(DATA_SIZE).decode()
auth_data = json.loads(user_data)
# print(auth_data)
print("username = "******"prime = " + str(auth_data['prime']))
print("generator= " + str(auth_data['generator']))
print("verifier = " + str(auth_data['password_verifier']))
# generate user-based server parameters
server_session = SRPServerSession(
SRPContext(auth_data['username'],
prime=auth_data['prime'],
generator=auth_data['generator']),
auth_data['password_verifier'])
server_public = server_session.public
print("server public= " + str(server_public))
server_data = json.dumps({'server_verifier':
server_public}) # 'server_salt' : server_salt})
# print(server_data)
conn.send(server_data.encode())
# receive client parameters
user_data = conn.recv(DATA_SIZE).decode()
client_parameters = json.loads(user_data)
# print(client_parameters)
class ProxyMrpAppleTV(asyncio.Protocol): # pylint: disable=too-many-instance-attributes # noqa
"""Implementation of a fake MRP Apple TV."""
def __init__(self, loop, credentials, atv_device_id):
"""Initialize a new instance of ProxyMrpAppleTV."""
self.loop = loop
self.credentials = credentials
self.atv_device_id = atv_device_id
self.server = None
self.buffer = b''
self.has_paired = False
self.transport = None
self.chacha = None
self.connection = None
self.input_key = None
self.output_key = None
self.mapping = {
protobuf.DEVICE_INFO_MESSAGE: self.handle_device_info,
protobuf.CRYPTO_PAIRING_MESSAGE: self.handle_crypto_pairing,
}
self._shared = None
self._session_key = None
self._signing_key = SigningKey(32 * b'\x01')
self._auth_private = self._signing_key.to_seed()
self._auth_public = self._signing_key.get_verifying_key().to_bytes()
self._verify_private = curve25519.Private(secret=32 * b'\x01')
self._verify_public = self._verify_private.get_public()
self.context = SRPContext('Pair-Setup',
str(1111),
prime=constants.PRIME_3072,
generator=constants.PRIME_3072_GEN,
hash_func=hashlib.sha512,
bits_salt=128)
self.username, self.verifier, self.salt = \
self.context.get_user_data_triplet()
context_server = SRPContext('Pair-Setup',
prime=constants.PRIME_3072,
generator=constants.PRIME_3072_GEN,
hash_func=hashlib.sha512,
bits_salt=128)
self._session = SRPServerSession(
context_server, self.verifier,
binascii.hexlify(self._auth_private).decode())
def start(self, address, port):
"""Start the proxy instance."""
# Establish connection to ATV
self.connection = MrpConnection(address, port, self.loop)
protocol = MrpProtocol(
self.loop, self.connection, SRPAuthHandler(),
MrpService(None, port, credentials=self.credentials))
self.loop.run_until_complete(
protocol.start(skip_initial_messages=True))
self.connection.listener = self
# Setup server used to publish a fake MRP server
coro = self.loop.create_server(lambda: self, '0.0.0.0')
self.server = self.loop.run_until_complete(coro)
_LOGGER.info('Started MRP server at port %d', self.port)
@property
def port(self):
"""Port used by MRP proxy server."""
return self.server.sockets[0].getsockname()[1]
def connection_made(self, transport):
"""Client did connect to proxy."""
self.transport = transport
def _send(self, message):
data = message.SerializeToString()
_LOGGER.info('<<(DECRYPTED): %s', message)
if self.chacha:
data = self.chacha.encrypt(data)
log_binary(_LOGGER, '<<(ENCRYPTED)', Message=message)
length = variant.write_variant(len(data))
self.transport.write(length + data)
def _send_raw(self, raw):
parsed = protobuf.ProtocolMessage()
parsed.ParseFromString(raw)
log_binary(_LOGGER, 'ATV->APP', Raw=raw)
_LOGGER.info('ATV->APP Parsed: %s', parsed)
if self.chacha:
raw = self.chacha.encrypt(raw)
log_binary(_LOGGER, 'ATV->APP', Encrypted=raw)
length = variant.write_variant(len(raw))
try:
self.transport.write(length + raw)
except Exception: # pylint: disable=broad-except
_LOGGER.exception('Failed to send to app')
def message_received(self, _, raw):
"""Message received from ATV."""
self._send_raw(raw)
def data_received(self, data):
"""Message received from iOS app/client."""
self.buffer += data
while self.buffer:
length, raw = variant.read_variant(self.buffer)
if len(raw) < length:
break
data = raw[:length]
self.buffer = raw[length:]
if self.chacha:
log_binary(_LOGGER, 'ENC Phone->ATV', Encrypted=data)
data = self.chacha.decrypt(data)
parsed = protobuf.ProtocolMessage()
parsed.ParseFromString(data)
_LOGGER.info('(DEC Phone->ATV): %s', parsed)
try:
def unhandled_message(_, raw):
self.connection.send_raw(raw)
self.mapping.get(parsed.type, unhandled_message)(parsed, data)
except Exception: # pylint: disable=broad-except
_LOGGER.exception('Error while dispatching message')
def handle_device_info(self, message, _):
"""Handle received device information message."""
_LOGGER.debug('Received device info message')
# TODO: Consolidate this better with message.device_information(...)
resp = messages.create(protobuf.DEVICE_INFO_MESSAGE)
resp.identifier = message.identifier
resp.inner().uniqueIdentifier = self.atv_device_id.decode()
resp.inner().name = 'ATVProxy'
resp.inner().systemBuildVersion = '15K600'
resp.inner().applicationBundleIdentifier = 'com.apple.mediaremoted'
resp.inner().protocolVersion = 1
resp.inner().lastSupportedMessageType = 58
resp.inner().supportsSystemPairing = True
resp.inner().allowsPairing = True
resp.inner().systemMediaApplication = "com.apple.TVMusic"
resp.inner().supportsACL = True
resp.inner().supportsSharedQueue = True
resp.inner().supportsExtendedMotion = True
resp.inner().sharedQueueVersion = 2
self._send(resp)
def handle_crypto_pairing(self, message, _):
"""Handle incoming crypto pairing message."""
_LOGGER.debug('Received crypto pairing message')
pairing_data = tlv8.read_tlv(message.inner().pairingData)
seqno = pairing_data[tlv8.TLV_SEQ_NO][0]
getattr(self, "_seqno_" + str(seqno))(pairing_data)
def _seqno_1(self, pairing_data):
if self.has_paired:
server_pub_key = self._verify_public.serialize()
client_pub_key = pairing_data[tlv8.TLV_PUBLIC_KEY]
self._shared = self._verify_private.get_shared_key(
curve25519.Public(client_pub_key), hashfunc=lambda x: x)
session_key = hkdf_expand('Pair-Verify-Encrypt-Salt',
'Pair-Verify-Encrypt-Info', self._shared)
info = server_pub_key + self.atv_device_id + client_pub_key
signature = SigningKey(self._signing_key.to_seed()).sign(info)
tlv = tlv8.write_tlv({
tlv8.TLV_IDENTIFIER: self.atv_device_id,
tlv8.TLV_SIGNATURE: signature
})
chacha = chacha20.Chacha20Cipher(session_key, session_key)
encrypted = chacha.encrypt(tlv, nounce='PV-Msg02'.encode())
msg = messages.crypto_pairing({
tlv8.TLV_SEQ_NO: b'\x02',
tlv8.TLV_PUBLIC_KEY: server_pub_key,
tlv8.TLV_ENCRYPTED_DATA: encrypted
})
self.output_key = hkdf_expand('MediaRemote-Salt',
'MediaRemote-Write-Encryption-Key',
self._shared)
self.input_key = hkdf_expand('MediaRemote-Salt',
'MediaRemote-Read-Encryption-Key',
self._shared)
log_binary(_LOGGER,
'Keys',
Output=self.output_key,
Input=self.input_key)
else:
msg = messages.crypto_pairing({
tlv8.TLV_SALT:
binascii.unhexlify(self.salt),
tlv8.TLV_PUBLIC_KEY:
binascii.unhexlify(self._session.public),
tlv8.TLV_SEQ_NO:
b'\x02'
})
self._send(msg)
def _seqno_3(self, pairing_data):
if self.has_paired:
self._send(messages.crypto_pairing({tlv8.TLV_SEQ_NO: b'\x04'}))
self.chacha = chacha20.Chacha20Cipher(self.input_key,
self.output_key)
else:
pubkey = binascii.hexlify(
pairing_data[tlv8.TLV_PUBLIC_KEY]).decode()
self._session.process(pubkey, self.salt)
proof = binascii.unhexlify(self._session.key_proof_hash)
assert self._session.verify_proof(
binascii.hexlify(pairing_data[tlv8.TLV_PROOF]))
msg = messages.crypto_pairing({
tlv8.TLV_PROOF: proof,
tlv8.TLV_SEQ_NO: b'\x04'
})
self._send(msg)
def _seqno_5(self, _):
self._session_key = hkdf_expand('Pair-Setup-Encrypt-Salt',
'Pair-Setup-Encrypt-Info',
binascii.unhexlify(self._session.key))
acc_device_x = hkdf_expand('Pair-Setup-Accessory-Sign-Salt',
'Pair-Setup-Accessory-Sign-Info',
binascii.unhexlify(self._session.key))
device_info = acc_device_x + self.atv_device_id + self._auth_public
signature = self._signing_key.sign(device_info)
tlv = tlv8.write_tlv({
tlv8.TLV_IDENTIFIER: self.atv_device_id,
tlv8.TLV_PUBLIC_KEY: self._auth_public,
tlv8.TLV_SIGNATURE: signature
})
chacha = chacha20.Chacha20Cipher(self._session_key, self._session_key)
encrypted = chacha.encrypt(tlv, nounce='PS-Msg06'.encode())
msg = messages.crypto_pairing({
tlv8.TLV_SEQ_NO: b'\x06',
tlv8.TLV_ENCRYPTED_DATA: encrypted,
})
self.has_paired = True
self._send(msg)