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#!/usr/bin/env python3
# Copyright (c) 2022 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
import random
import time
from enum import Enum
from test_framework.messages import MAGIC_BYTES
from test_framework.p2p import P2PInterface
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import random_bitflip
from test_framework.v2_p2p import (
EncryptedP2PState,
MAX_GARBAGE_LEN,
)
class TestType(Enum):
""" Scenarios to be tested:
1. EARLY_KEY_RESPONSE - The responder needs to wait until one byte is received which does not match the 16 bytes
consisting of network magic followed by "version\x00\x00\x00\x00\x00" before sending out its ellswift + garbage bytes
2. EXCESS_GARBAGE - Disconnection happens when > MAX_GARBAGE_LEN bytes garbage is sent
3. WRONG_GARBAGE_TERMINATOR - Disconnection happens when incorrect garbage terminator is sent
4. WRONG_GARBAGE - Disconnection happens when garbage bytes that is sent is different from what the peer receives
5. SEND_NO_AAD - Disconnection happens when AAD of first encrypted packet after the garbage terminator is not filled
6. SEND_NON_EMPTY_VERSION_PACKET - non-empty version packet is simply ignored
"""
EARLY_KEY_RESPONSE = 0
EXCESS_GARBAGE = 1
WRONG_GARBAGE_TERMINATOR = 2
WRONG_GARBAGE = 3
SEND_NO_AAD = 4
SEND_NON_EMPTY_VERSION_PACKET = 5
class EarlyKeyResponseState(EncryptedP2PState):
""" Modify v2 P2P protocol functions for testing EARLY_KEY_RESPONSE scenario"""
def __init__(self, initiating, net):
super().__init__(initiating=initiating, net=net)
self.can_data_be_received = False # variable used to assert if data is received on recvbuf.
def initiate_v2_handshake(self):
"""Send ellswift and garbage bytes in 2 parts when TestType = (EARLY_KEY_RESPONSE)"""
self.generate_keypair_and_garbage()
return b""
class ExcessGarbageState(EncryptedP2PState):
"""Generate > MAX_GARBAGE_LEN garbage bytes"""
def generate_keypair_and_garbage(self):
garbage_len = MAX_GARBAGE_LEN + random.randrange(1, MAX_GARBAGE_LEN + 1)
return super().generate_keypair_and_garbage(garbage_len)
class WrongGarbageTerminatorState(EncryptedP2PState):
"""Add option for sending wrong garbage terminator"""
def generate_keypair_and_garbage(self):
garbage_len = random.randrange(MAX_GARBAGE_LEN//2)
return super().generate_keypair_and_garbage(garbage_len)
def complete_handshake(self, response):
length, handshake_bytes = super().complete_handshake(response)
# first 16 bytes returned by complete_handshake() is the garbage terminator
wrong_garbage_terminator = random_bitflip(handshake_bytes[:16])
return length, wrong_garbage_terminator + handshake_bytes[16:]
class WrongGarbageState(EncryptedP2PState):
"""Generate tampered garbage bytes"""
def generate_keypair_and_garbage(self):
garbage_len = random.randrange(1, MAX_GARBAGE_LEN)
ellswift_garbage_bytes = super().generate_keypair_and_garbage(garbage_len)
# assume that garbage bytes sent to TestNode were tampered with
return ellswift_garbage_bytes[:64] + random_bitflip(ellswift_garbage_bytes[64:])
class NoAADState(EncryptedP2PState):
"""Add option for not filling first encrypted packet after garbage terminator with AAD"""
def generate_keypair_and_garbage(self):
garbage_len = random.randrange(1, MAX_GARBAGE_LEN)
return super().generate_keypair_and_garbage(garbage_len)
def complete_handshake(self, response):
self.sent_garbage = b'' # do not authenticate the garbage which is sent
return super().complete_handshake(response)
class NonEmptyVersionPacketState(EncryptedP2PState):
""""Add option for sending non-empty transport version packet."""
def complete_handshake(self, response):
self.transport_version = random.randbytes(5)
return super().complete_handshake(response)
class MisbehavingV2Peer(P2PInterface):
"""Custom implementation of P2PInterface which uses modified v2 P2P protocol functions for testing purposes."""
def __init__(self, test_type):
super().__init__()
self.test_type = test_type
def connection_made(self, transport):
if self.test_type == TestType.EARLY_KEY_RESPONSE:
self.v2_state = EarlyKeyResponseState(initiating=True, net='regtest')
elif self.test_type == TestType.EXCESS_GARBAGE:
self.v2_state = ExcessGarbageState(initiating=True, net='regtest')
elif self.test_type == TestType.WRONG_GARBAGE_TERMINATOR:
self.v2_state = WrongGarbageTerminatorState(initiating=True, net='regtest')
elif self.test_type == TestType.WRONG_GARBAGE:
self.v2_state = WrongGarbageState(initiating=True, net='regtest')
elif self.test_type == TestType.SEND_NO_AAD:
self.v2_state = NoAADState(initiating=True, net='regtest')
elif TestType.SEND_NON_EMPTY_VERSION_PACKET:
self.v2_state = NonEmptyVersionPacketState(initiating=True, net='regtest')
super().connection_made(transport)
def data_received(self, t):
if self.test_type == TestType.EARLY_KEY_RESPONSE:
# check that data can be received on recvbuf only when mismatch from V1_PREFIX happens
assert self.v2_state.can_data_be_received
else:
super().data_received(t)
class EncryptedP2PMisbehaving(BitcoinTestFramework):
def set_test_params(self):
self.num_nodes = 1
self.extra_args = [["-v2transport=1", "-peertimeout=3"]]
def run_test(self):
self.test_earlykeyresponse()
self.test_v2disconnection()
def test_earlykeyresponse(self):
self.log.info('Sending ellswift bytes in parts to ensure that response from responder is received only when')
self.log.info('ellswift bytes have a mismatch from the 16 bytes(network magic followed by "version\\x00\\x00\\x00\\x00\\x00")')
node0 = self.nodes[0]
node0.setmocktime(int(time.time()))
self.log.info('Sending first 4 bytes of ellswift which match network magic')
self.log.info('If a response is received, assertion failure would happen in our custom data_received() function')
peer1 = node0.add_p2p_connection(MisbehavingV2Peer(TestType.EARLY_KEY_RESPONSE), wait_for_verack=False, send_version=False, supports_v2_p2p=True, wait_for_v2_handshake=False)
peer1.send_raw_message(MAGIC_BYTES['regtest'])
self.log.info('Sending remaining ellswift and garbage which are different from V1_PREFIX. Since a response is')
self.log.info('expected now, our custom data_received() function wouldn\'t result in assertion failure')
peer1.v2_state.can_data_be_received = True
self.wait_until(lambda: peer1.v2_state.ellswift_ours)
peer1.send_raw_message(peer1.v2_state.ellswift_ours[4:] + peer1.v2_state.sent_garbage)
# Ensure that the bytes sent after 4 bytes network magic are actually received.
self.wait_until(lambda: node0.getpeerinfo()[-1]["bytesrecv"] > 4)
self.wait_until(lambda: node0.getpeerinfo()[-1]["bytessent"] > 0)
with node0.assert_debug_log(['V2 handshake timeout peer=0']):
node0.bumpmocktime(4) # `InactivityCheck()` triggers now
peer1.wait_for_disconnect(timeout=1)
self.log.info('successful disconnection since modified ellswift was sent as response')
def test_v2disconnection(self):
# test v2 disconnection scenarios
node0 = self.nodes[0]
expected_debug_message = [
[], # EARLY_KEY_RESPONSE
["V2 transport error: missing garbage terminator, peer=1"], # EXCESS_GARBAGE
["V2 handshake timeout peer=3"], # WRONG_GARBAGE_TERMINATOR
["V2 transport error: packet decryption failure"], # WRONG_GARBAGE
["V2 transport error: packet decryption failure"], # SEND_NO_AAD
[], # SEND_NON_EMPTY_VERSION_PACKET
]
for test_type in TestType:
if test_type == TestType.EARLY_KEY_RESPONSE:
continue
elif test_type == TestType.SEND_NON_EMPTY_VERSION_PACKET:
node0.add_p2p_connection(MisbehavingV2Peer(test_type), wait_for_verack=True, send_version=True, supports_v2_p2p=True)
self.log.info(f"No disconnection for {test_type.name}")
else:
with node0.assert_debug_log(expected_debug_message[test_type.value], timeout=5):
node0.setmocktime(int(time.time()))
peer1 = node0.add_p2p_connection(MisbehavingV2Peer(test_type), wait_for_verack=False, send_version=False, supports_v2_p2p=True, expect_success=False)
# Make a passing connection for more robust disconnection checking.
peer2 = node0.add_p2p_connection(P2PInterface())
assert peer2.is_connected
node0.bumpmocktime(4) # `InactivityCheck()` triggers now
peer1.wait_for_disconnect()
self.log.info(f"Expected disconnection for {test_type.name}")
if __name__ == '__main__':
EncryptedP2PMisbehaving().main()
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