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#!/usr/bin/env python3
# Copyright (c) 2015-2020 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Test node responses to invalid network messages."""
from test_framework.messages import (
CBlockHeader,
CInv,
MAX_HEADERS_RESULTS,
MAX_INV_SIZE,
MAX_PROTOCOL_MESSAGE_LENGTH,
msg_getdata,
msg_headers,
msg_inv,
msg_ping,
MSG_TX,
ser_string,
)
from test_framework.p2p import (
P2PDataStore,
P2PInterface,
)
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import assert_equal
VALID_DATA_LIMIT = MAX_PROTOCOL_MESSAGE_LENGTH - 5 # Account for the 5-byte length prefix
class msg_unrecognized:
"""Nonsensical message. Modeled after similar types in test_framework.messages."""
msgtype = b'badmsg'
def __init__(self, *, str_data):
self.str_data = str_data.encode() if not isinstance(str_data, bytes) else str_data
def serialize(self):
return ser_string(self.str_data)
def __repr__(self):
return "{}(data={})".format(self.msgtype, self.str_data)
class InvalidMessagesTest(BitcoinTestFramework):
def set_test_params(self):
self.num_nodes = 1
self.setup_clean_chain = True
def run_test(self):
self.test_buffer()
self.test_magic_bytes()
self.test_checksum()
self.test_size()
self.test_msgtype()
self.test_oversized_inv_msg()
self.test_oversized_getdata_msg()
self.test_oversized_headers_msg()
self.test_resource_exhaustion()
def test_buffer(self):
self.log.info("Test message with header split across two buffers is received")
conn = self.nodes[0].add_p2p_connection(P2PDataStore())
# Create valid message
msg = conn.build_message(msg_ping(nonce=12345))
cut_pos = 12 # Chosen at an arbitrary position within the header
# Send message in two pieces
before = self.nodes[0].getnettotals()['totalbytesrecv']
conn.send_raw_message(msg[:cut_pos])
# Wait until node has processed the first half of the message
self.wait_until(lambda: self.nodes[0].getnettotals()['totalbytesrecv'] != before)
middle = self.nodes[0].getnettotals()['totalbytesrecv']
# If this assert fails, we've hit an unlikely race
# where the test framework sent a message in between the two halves
assert_equal(middle, before + cut_pos)
conn.send_raw_message(msg[cut_pos:])
conn.sync_with_ping(timeout=1)
self.nodes[0].disconnect_p2ps()
def test_magic_bytes(self):
self.log.info("Test message with invalid magic bytes disconnects peer")
conn = self.nodes[0].add_p2p_connection(P2PDataStore())
with self.nodes[0].assert_debug_log(['PROCESSMESSAGE: INVALID MESSAGESTART badmsg']):
msg = conn.build_message(msg_unrecognized(str_data="d"))
# modify magic bytes
msg = b'\xff' * 4 + msg[4:]
conn.send_raw_message(msg)
conn.wait_for_disconnect(timeout=1)
self.nodes[0].disconnect_p2ps()
def test_checksum(self):
self.log.info("Test message with invalid checksum logs an error")
conn = self.nodes[0].add_p2p_connection(P2PDataStore())
with self.nodes[0].assert_debug_log(['CHECKSUM ERROR (badmsg, 2 bytes), expected 78df0a04 was ffffffff']):
msg = conn.build_message(msg_unrecognized(str_data="d"))
# Checksum is after start bytes (4B), message type (12B), len (4B)
cut_len = 4 + 12 + 4
# modify checksum
msg = msg[:cut_len] + b'\xff' * 4 + msg[cut_len + 4:]
conn.send_raw_message(msg)
conn.sync_with_ping(timeout=1)
# Check that traffic is accounted for (24 bytes header + 2 bytes payload)
assert_equal(self.nodes[0].getpeerinfo()[0]['bytesrecv_per_msg']['*other*'], 26)
self.nodes[0].disconnect_p2ps()
def test_size(self):
self.log.info("Test message with oversized payload disconnects peer")
conn = self.nodes[0].add_p2p_connection(P2PDataStore())
with self.nodes[0].assert_debug_log(['']):
msg = msg_unrecognized(str_data="d" * (VALID_DATA_LIMIT + 1))
msg = conn.build_message(msg)
conn.send_raw_message(msg)
conn.wait_for_disconnect(timeout=1)
self.nodes[0].disconnect_p2ps()
def test_msgtype(self):
self.log.info("Test message with invalid message type logs an error")
conn = self.nodes[0].add_p2p_connection(P2PDataStore())
with self.nodes[0].assert_debug_log(['PROCESSMESSAGE: ERRORS IN HEADER']):
msg = msg_unrecognized(str_data="d")
msg.msgtype = b'\xff' * 12
msg = conn.build_message(msg)
# Modify msgtype
msg = msg[:7] + b'\x00' + msg[7 + 1:]
conn.send_raw_message(msg)
conn.sync_with_ping(timeout=1)
# Check that traffic is accounted for (24 bytes header + 2 bytes payload)
assert_equal(self.nodes[0].getpeerinfo()[0]['bytesrecv_per_msg']['*other*'], 26)
self.nodes[0].disconnect_p2ps()
def test_oversized_msg(self, msg, size):
msg_type = msg.msgtype.decode('ascii')
self.log.info("Test {} message of size {} is logged as misbehaving".format(msg_type, size))
with self.nodes[0].assert_debug_log(['Misbehaving', '{} message size = {}'.format(msg_type, size)]):
self.nodes[0].add_p2p_connection(P2PInterface()).send_and_ping(msg)
self.nodes[0].disconnect_p2ps()
def test_oversized_inv_msg(self):
size = MAX_INV_SIZE + 1
self.test_oversized_msg(msg_inv([CInv(MSG_TX, 1)] * size), size)
def test_oversized_getdata_msg(self):
size = MAX_INV_SIZE + 1
self.test_oversized_msg(msg_getdata([CInv(MSG_TX, 1)] * size), size)
def test_oversized_headers_msg(self):
size = MAX_HEADERS_RESULTS + 1
self.test_oversized_msg(msg_headers([CBlockHeader()] * size), size)
def test_resource_exhaustion(self):
self.log.info("Test node stays up despite many large junk messages")
conn = self.nodes[0].add_p2p_connection(P2PDataStore())
conn2 = self.nodes[0].add_p2p_connection(P2PDataStore())
msg_at_size = msg_unrecognized(str_data="b" * VALID_DATA_LIMIT)
assert len(msg_at_size.serialize()) == MAX_PROTOCOL_MESSAGE_LENGTH
self.log.info("(a) Send 80 messages, each of maximum valid data size (4MB)")
for _ in range(80):
conn.send_message(msg_at_size)
# Check that, even though the node is being hammered by nonsense from one
# connection, it can still service other peers in a timely way.
self.log.info("(b) Check node still services peers in a timely way")
for _ in range(20):
conn2.sync_with_ping(timeout=2)
self.log.info("(c) Wait for node to drop junk messages, while remaining connected")
conn.sync_with_ping(timeout=400)
# Despite being served up a bunch of nonsense, the peers should still be connected.
assert conn.is_connected
assert conn2.is_connected
self.nodes[0].disconnect_p2ps()
if __name__ == '__main__':
InvalidMessagesTest().main()
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