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#!/usr/bin/env python3
# Copyright (c) 2017-2018 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 various fingerprinting protections.
If a stale block more than a month old or its header are requested by a peer,
the node should pretend that it does not have it to avoid fingerprinting.
"""
import time
from test_framework.blocktools import (create_block, create_coinbase)
from test_framework.messages import CInv
from test_framework.mininode import (
P2PInterface,
msg_headers,
msg_block,
msg_getdata,
msg_getheaders,
)
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import (
assert_equal,
wait_until,
)
class P2PFingerprintTest(BitcoinTestFramework):
def set_test_params(self):
self.setup_clean_chain = True
self.num_nodes = 1
def skip_test_if_missing_module(self):
self.skip_if_no_wallet()
# Build a chain of blocks on top of given one
def build_chain(self, nblocks, prev_hash, prev_height, prev_median_time):
blocks = []
for _ in range(nblocks):
coinbase = create_coinbase(prev_height + 1)
block_time = prev_median_time + 1
block = create_block(int(prev_hash, 16), coinbase, block_time)
block.solve()
blocks.append(block)
prev_hash = block.hash
prev_height += 1
prev_median_time = block_time
return blocks
# Send a getdata request for a given block hash
def send_block_request(self, block_hash, node):
msg = msg_getdata()
msg.inv.append(CInv(2, block_hash)) # 2 == "Block"
node.send_message(msg)
# Send a getheaders request for a given single block hash
def send_header_request(self, block_hash, node):
msg = msg_getheaders()
msg.hashstop = block_hash
node.send_message(msg)
# Check whether last block received from node has a given hash
def last_block_equals(self, expected_hash, node):
block_msg = node.last_message.get("block")
return block_msg and block_msg.block.rehash() == expected_hash
# Check whether last block header received from node has a given hash
def last_header_equals(self, expected_hash, node):
headers_msg = node.last_message.get("headers")
return (headers_msg and
headers_msg.headers and
headers_msg.headers[0].rehash() == expected_hash)
# Checks that stale blocks timestamped more than a month ago are not served
# by the node while recent stale blocks and old active chain blocks are.
# This does not currently test that stale blocks timestamped within the
# last month but that have over a month's worth of work are also withheld.
def run_test(self):
node0 = self.nodes[0].add_p2p_connection(P2PInterface())
# Set node time to 60 days ago
self.nodes[0].setmocktime(int(time.time()) - 60 * 24 * 60 * 60)
# Generating a chain of 10 blocks
block_hashes = self.nodes[0].generate(nblocks=10)
# Create longer chain starting 2 blocks before current tip
height = len(block_hashes) - 2
block_hash = block_hashes[height - 1]
block_time = self.nodes[0].getblockheader(block_hash)["mediantime"] + 1
new_blocks = self.build_chain(5, block_hash, height, block_time)
# Force reorg to a longer chain
node0.send_message(msg_headers(new_blocks))
node0.wait_for_getdata()
for block in new_blocks:
node0.send_and_ping(msg_block(block))
# Check that reorg succeeded
assert_equal(self.nodes[0].getblockcount(), 13)
stale_hash = int(block_hashes[-1], 16)
# Check that getdata request for stale block succeeds
self.send_block_request(stale_hash, node0)
test_function = lambda: self.last_block_equals(stale_hash, node0)
wait_until(test_function, timeout=3)
# Check that getheader request for stale block header succeeds
self.send_header_request(stale_hash, node0)
test_function = lambda: self.last_header_equals(stale_hash, node0)
wait_until(test_function, timeout=3)
# Longest chain is extended so stale is much older than chain tip
self.nodes[0].setmocktime(0)
tip = self.nodes[0].generate(nblocks=1)[0]
assert_equal(self.nodes[0].getblockcount(), 14)
# Send getdata & getheaders to refresh last received getheader message
block_hash = int(tip, 16)
self.send_block_request(block_hash, node0)
self.send_header_request(block_hash, node0)
node0.sync_with_ping()
# Request for very old stale block should now fail
self.send_block_request(stale_hash, node0)
time.sleep(3)
assert not self.last_block_equals(stale_hash, node0)
# Request for very old stale block header should now fail
self.send_header_request(stale_hash, node0)
time.sleep(3)
assert not self.last_header_equals(stale_hash, node0)
# Verify we can fetch very old blocks and headers on the active chain
block_hash = int(block_hashes[2], 16)
self.send_block_request(block_hash, node0)
self.send_header_request(block_hash, node0)
node0.sync_with_ping()
self.send_block_request(block_hash, node0)
test_function = lambda: self.last_block_equals(block_hash, node0)
wait_until(test_function, timeout=3)
self.send_header_request(block_hash, node0)
test_function = lambda: self.last_header_equals(block_hash, node0)
wait_until(test_function, timeout=3)
if __name__ == '__main__':
P2PFingerprintTest().main()
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