#!/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.mininode import ( P2PDataStore, P2PInterface, ) from test_framework.test_framework import BitcoinTestFramework from test_framework.util import ( assert_equal, wait_until, ) 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 = int(self.nodes[0].getnettotals()['totalbytesrecv']) conn.send_raw_message(msg[:cut_pos]) # Wait until node has processed the first half of the message wait_until(lambda: int(self.nodes[0].getnettotals()['totalbytesrecv']) != before) middle = int(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) 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) 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()