test/functional/p2p-fingerprint.py

   1 #!/usr/bin/env python3
   2 # Copyright (c) 2017 The Bitcoin Core developers
   3 # Distributed under the MIT software license, see the accompanying
   4 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5 """Test various fingerprinting protections.
   6
   7 If an stale block more than a month old or its header are requested by a peer,
   8 the node should pretend that it does not have it to avoid fingerprinting.
   9 """
  10
  11 import time
  12
  13 from test_framework.blocktools import (create_block, create_coinbase)
  14 from test_framework.mininode import (
  15     CInv,
  16     P2PInterface,
  17     msg_headers,
  18     msg_block,
  19     msg_getdata,
  20     msg_getheaders,
  21     network_thread_start,
  22     wait_until,
  23 )
  24 from test_framework.test_framework import BitcoinTestFramework
  25 from test_framework.util import (
  26     assert_equal,
  27 )
  28
  29 class P2PFingerprintTest(BitcoinTestFramework):
  30     def set_test_params(self):
  31         self.setup_clean_chain = True
  32         self.num_nodes = 1
  33
  34     # Build a chain of blocks on top of given one
  35     def build_chain(self, nblocks, prev_hash, prev_height, prev_median_time):
  36         blocks = []
  37         for _ in range(nblocks):
  38             coinbase = create_coinbase(prev_height + 1)
  39             block_time = prev_median_time + 1
  40             block = create_block(int(prev_hash, 16), coinbase, block_time)
  41             block.solve()
  42
  43             blocks.append(block)
  44             prev_hash = block.hash
  45             prev_height += 1
  46             prev_median_time = block_time
  47         return blocks
  48
  49     # Send a getdata request for a given block hash
  50     def send_block_request(self, block_hash, node):
  51         msg = msg_getdata()
  52         msg.inv.append(CInv(2, block_hash))  # 2 == "Block"
  53         node.send_message(msg)
  54
  55     # Send a getheaders request for a given single block hash
  56     def send_header_request(self, block_hash, node):
  57         msg = msg_getheaders()
  58         msg.hashstop = block_hash
  59         node.send_message(msg)
  60
  61     # Check whether last block received from node has a given hash
  62     def last_block_equals(self, expected_hash, node):
  63         block_msg = node.last_message.get("block")
  64         return block_msg and block_msg.block.rehash() == expected_hash
  65
  66     # Check whether last block header received from node has a given hash
  67     def last_header_equals(self, expected_hash, node):
  68         headers_msg = node.last_message.get("headers")
  69         return (headers_msg and
  70                 headers_msg.headers and
  71                 headers_msg.headers[0].rehash() == expected_hash)
  72
  73     # Checks that stale blocks timestamped more than a month ago are not served
  74     # by the node while recent stale blocks and old active chain blocks are.
  75     # This does not currently test that stale blocks timestamped within the
  76     # last month but that have over a month's worth of work are also withheld.
  77     def run_test(self):
  78         node0 = self.nodes[0].add_p2p_connection(P2PInterface())
  79
  80         network_thread_start()
  81         node0.wait_for_verack()
  82
  83         # Set node time to 60 days ago
  84         self.nodes[0].setmocktime(int(time.time()) - 60 * 24 * 60 * 60)
  85
  86         # Generating a chain of 10 blocks
  87         block_hashes = self.nodes[0].generate(nblocks=10)
  88
  89         # Create longer chain starting 2 blocks before current tip
  90         height = len(block_hashes) - 2
  91         block_hash = block_hashes[height - 1]
  92         block_time = self.nodes[0].getblockheader(block_hash)["mediantime"] + 1
  93         new_blocks = self.build_chain(5, block_hash, height, block_time)
  94
  95         # Force reorg to a longer chain
  96         node0.send_message(msg_headers(new_blocks))
  97         node0.wait_for_getdata()
  98         for block in new_blocks:
  99             node0.send_and_ping(msg_block(block))
 100
 101         # Check that reorg succeeded
 102         assert_equal(self.nodes[0].getblockcount(), 13)
 103
 104         stale_hash = int(block_hashes[-1], 16)
 105
 106         # Check that getdata request for stale block succeeds
 107         self.send_block_request(stale_hash, node0)
 108         test_function = lambda: self.last_block_equals(stale_hash, node0)
 109         wait_until(test_function, timeout=3)
 110
 111         # Check that getheader request for stale block header succeeds
 112         self.send_header_request(stale_hash, node0)
 113         test_function = lambda: self.last_header_equals(stale_hash, node0)
 114         wait_until(test_function, timeout=3)
 115
 116         # Longest chain is extended so stale is much older than chain tip
 117         self.nodes[0].setmocktime(0)
 118         tip = self.nodes[0].generate(nblocks=1)[0]
 119         assert_equal(self.nodes[0].getblockcount(), 14)
 120
 121         # Send getdata & getheaders to refresh last received getheader message
 122         block_hash = int(tip, 16)
 123         self.send_block_request(block_hash, node0)
 124         self.send_header_request(block_hash, node0)
 125         node0.sync_with_ping()
 126
 127         # Request for very old stale block should now fail
 128         self.send_block_request(stale_hash, node0)
 129         time.sleep(3)
 130         assert not self.last_block_equals(stale_hash, node0)
 131
 132         # Request for very old stale block header should now fail
 133         self.send_header_request(stale_hash, node0)
 134         time.sleep(3)
 135         assert not self.last_header_equals(stale_hash, node0)
 136
 137         # Verify we can fetch very old blocks and headers on the active chain
 138         block_hash = int(block_hashes[2], 16)
 139         self.send_block_request(block_hash, node0)
 140         self.send_header_request(block_hash, node0)
 141         node0.sync_with_ping()
 142
 143         self.send_block_request(block_hash, node0)
 144         test_function = lambda: self.last_block_equals(block_hash, node0)
 145         wait_until(test_function, timeout=3)
 146
 147         self.send_header_request(block_hash, node0)
 148         test_function = lambda: self.last_header_equals(block_hash, node0)
 149         wait_until(test_function, timeout=3)
 150
 151 if __name__ == '__main__':
 152     P2PFingerprintTest().main()