Differential D6178 Diff 20473 test/functional/p2p_invalid_messages.py

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test/functional/p2p_invalid_messages.py

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				#!/usr/bin/env python3
				# Copyright (c) 2015-2018 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."""
				import struct

				from test_framework import messages
				from test_framework.mininode import P2PDataStore
				from test_framework.test_framework import BitcoinTestFramework


				class msg_unrecognized:
				"""Nonsensical message. Modeled after similar types in test_framework.messages."""

				command = 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 messages.ser_string(self.str_data)

				def __repr__(self):
				return "{}(data={})".format(self.command, self.str_data)


				class msg_nametoolong(msg_unrecognized):

				command = b'thisnameiswayyyyyyyyytoolong'


				class InvalidMessagesTest(BitcoinTestFramework):

				def set_test_params(self):
				self.num_nodes = 1
				self.setup_clean_chain = True

				def run_test(self):
				"""
				0. Send a bunch of large (2MB) messages of an unrecognized type. Check to see
				that it isn't an effective DoS against the node.

				1. Send an oversized (2MB+) message and check that we're disconnected.

				2. Send a few messages with an incorrect data size in the header, ensure the
				messages are ignored.

				3. Send an unrecognized message with a command name longer than 12 characters.

				"""
				node = self.nodes[0]
				self.node = node
				node.add_p2p_connection(P2PDataStore())
				conn2 = node.add_p2p_connection(P2PDataStore())

				# 2MB, per MAX_PROTOCOL_MESSAGE_LENGTH
				msg_limit = 2 * 1024 * 1024
				# Account for the 4-byte length prefix
				valid_data_limit = msg_limit - 5

				#
				# 0.
				#
				# Send as large a message as is valid, ensure we aren't disconnected but
				# also can't exhaust resources.
				#
				msg_at_size = msg_unrecognized("b" * valid_data_limit)
				assert len(msg_at_size.serialize()) == msg_limit

				with node.assert_memory_usage_stable(perc_increase_allowed=0.03):
				self.log.info(
				"Sending a bunch of large, junk messages to test "
				"memory exhaustion. May take a bit...")

				# Run a bunch of times to test for memory exhaustion.
				for _ in range(80):
				node.p2p.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.
				for _ in range(20):
				conn2.sync_with_ping(timeout=2)

				# Peer 1, despite serving up a bunch of nonsense, should still be
				# connected.
				self.log.info("Waiting for node to drop junk messages.")
				node.p2p.sync_with_ping(timeout=30)
				assert node.p2p.is_connected

				#
				# 1.
				#
				# Send an oversized message, ensure we're disconnected.
				#
				msg_over_size = msg_unrecognized("b" * (valid_data_limit + 1))
				assert len(msg_over_size.serialize()) == (msg_limit + 1)

				with node.assert_debug_log(["Oversized header detected"]):
				# An unknown message type (or any message type) over
				# MAX_PROTOCOL_MESSAGE_LENGTH should result in a disconnect.
				node.p2p.send_message(msg_over_size)
				node.p2p.wait_for_disconnect(timeout=4)

				node.disconnect_p2ps()
				conn = node.add_p2p_connection(P2PDataStore())
				conn.wait_for_verack()

				#
				# 2.
				#
				# Send messages with an incorrect data size in the header.
				#
				actual_size = 100
				msg = msg_unrecognized("b" * actual_size)

				# TODO: handle larger-than cases. I haven't been able to pin down what
				# behavior to expect.
				for wrong_size in (2, 77, 78, 79):
				self.log.info(
				"Sending a message with incorrect size of {}".format(wrong_size))

				# Unmodified message should submit okay.
				node.p2p.send_and_ping(msg)

				# A message lying about its data size results in a disconnect when the incorrect
				# data size is less than the actual size.
				#
				# TODO: why does behavior change at 78 bytes?
				#
				node.p2p.send_raw_message(
				self._tweak_msg_data_size(
				msg, wrong_size))

				# For some reason unknown to me, we sometimes have to push additional data to the
				# peer in order for it to realize a disconnect.
				try:
				node.p2p.send_message(messages.msg_ping(nonce=123123))
				except IOError:
				pass

				node.p2p.wait_for_disconnect(timeout=10)
				node.disconnect_p2ps()
				node.add_p2p_connection(P2PDataStore())

				#
				# 3.
				#
				# Send a message with a too-long command name.
				#
				node.p2p.send_message(msg_nametoolong("foobar"))
				node.p2p.wait_for_disconnect(timeout=4)

				# Node is still up.
				conn = node.add_p2p_connection(P2PDataStore())
				conn.sync_with_ping()

				def _tweak_msg_data_size(self, message, wrong_size):
				"""
				Return a raw message based on another message but with an incorrect data size in
				the message header.
				"""
				raw_msg = self.node.p2p.build_message(message)

				bad_size_bytes = struct.pack("<I", wrong_size)
				num_header_bytes_before_size = 4 + 12

				# Replace the correct data size in the message with an incorrect one.
				raw_msg_with_wrong_size = (
				raw_msg[:num_header_bytes_before_size] +
				bad_size_bytes +
				raw_msg[(num_header_bytes_before_size + len(bad_size_bytes)):]
				)
				assert len(raw_msg) == len(raw_msg_with_wrong_size)

				return raw_msg_with_wrong_size


				if __name__ == '__main__':
				InvalidMessagesTest().main()