diff options
| -rw-r--r-- | src/net_processing.cpp | 37 | ||||
| -rwxr-xr-x | test/functional/p2p-fingerprint.py | 158 | ||||
| -rwxr-xr-x | test/functional/test_framework/mininode.py | 4 | ||||
| -rwxr-xr-x | test/functional/test_runner.py | 1 |
4 files changed, 189 insertions, 11 deletions
diff --git a/src/net_processing.cpp b/src/net_processing.cpp index 7fced41d4f..b5e37722df 100644 --- a/src/net_processing.cpp +++ b/src/net_processing.cpp @@ -61,6 +61,14 @@ static std::vector<std::pair<uint256, CTransactionRef>> vExtraTxnForCompact GUAR static const uint64_t RANDOMIZER_ID_ADDRESS_RELAY = 0x3cac0035b5866b90ULL; // SHA256("main address relay")[0:8] +/// Age after which a stale block will no longer be served if requested as +/// protection against fingerprinting. Set to one month, denominated in seconds. +static const int STALE_RELAY_AGE_LIMIT = 30 * 24 * 60 * 60; + +/// Age after which a block is considered historical for purposes of rate +/// limiting block relay. Set to one week, denominated in seconds. +static const int HISTORICAL_BLOCK_AGE = 7 * 24 * 60 * 60; + // Internal stuff namespace { /** Number of nodes with fSyncStarted. */ @@ -706,6 +714,17 @@ void Misbehaving(NodeId pnode, int howmuch) // blockchain -> download logic notification // +// To prevent fingerprinting attacks, only send blocks/headers outside of the +// active chain if they are no more than a month older (both in time, and in +// best equivalent proof of work) than the best header chain we know about. +static bool StaleBlockRequestAllowed(const CBlockIndex* pindex, const Consensus::Params& consensusParams) +{ + AssertLockHeld(cs_main); + return (pindexBestHeader != nullptr) && + (pindexBestHeader->GetBlockTime() - pindex->GetBlockTime() < STALE_RELAY_AGE_LIMIT) && + (GetBlockProofEquivalentTime(*pindexBestHeader, *pindex, *pindexBestHeader, consensusParams) < STALE_RELAY_AGE_LIMIT); +} + PeerLogicValidation::PeerLogicValidation(CConnman* connmanIn) : connman(connmanIn) { // Initialize global variables that cannot be constructed at startup. recentRejects.reset(new CRollingBloomFilter(120000, 0.000001)); @@ -983,13 +1002,8 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam if (chainActive.Contains(mi->second)) { send = true; } else { - static const int nOneMonth = 30 * 24 * 60 * 60; - // To prevent fingerprinting attacks, only send blocks outside of the active - // chain if they are valid, and no more than a month older (both in time, and in - // best equivalent proof of work) than the best header chain we know about. - send = mi->second->IsValid(BLOCK_VALID_SCRIPTS) && (pindexBestHeader != nullptr) && - (pindexBestHeader->GetBlockTime() - mi->second->GetBlockTime() < nOneMonth) && - (GetBlockProofEquivalentTime(*pindexBestHeader, *mi->second, *pindexBestHeader, consensusParams) < nOneMonth); + send = mi->second->IsValid(BLOCK_VALID_SCRIPTS) && + StaleBlockRequestAllowed(mi->second, consensusParams); if (!send) { LogPrintf("%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom->GetId()); } @@ -997,8 +1011,7 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam } // disconnect node in case we have reached the outbound limit for serving historical blocks // never disconnect whitelisted nodes - static const int nOneWeek = 7 * 24 * 60 * 60; // assume > 1 week = historical - if (send && connman->OutboundTargetReached(true) && ( ((pindexBestHeader != nullptr) && (pindexBestHeader->GetBlockTime() - mi->second->GetBlockTime() > nOneWeek)) || inv.type == MSG_FILTERED_BLOCK) && !pfrom->fWhitelisted) + if (send && connman->OutboundTargetReached(true) && ( ((pindexBestHeader != nullptr) && (pindexBestHeader->GetBlockTime() - mi->second->GetBlockTime() > HISTORICAL_BLOCK_AGE)) || inv.type == MSG_FILTERED_BLOCK) && !pfrom->fWhitelisted) { LogPrint(BCLog::NET, "historical block serving limit reached, disconnect peer=%d\n", pfrom->GetId()); @@ -1723,6 +1736,12 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr if (mi == mapBlockIndex.end()) return true; pindex = (*mi).second; + + if (!chainActive.Contains(pindex) && + !StaleBlockRequestAllowed(pindex, chainparams.GetConsensus())) { + LogPrintf("%s: ignoring request from peer=%i for old block header that isn't in the main chain\n", __func__, pfrom->GetId()); + return true; + } } else { diff --git a/test/functional/p2p-fingerprint.py b/test/functional/p2p-fingerprint.py new file mode 100755 index 0000000000..fe60c6cd46 --- /dev/null +++ b/test/functional/p2p-fingerprint.py @@ -0,0 +1,158 @@ +#!/usr/bin/env python3 +# Copyright (c) 2017 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 an 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.mininode import ( + CInv, + NetworkThread, + NodeConn, + NodeConnCB, + msg_headers, + msg_block, + msg_getdata, + msg_getheaders, + wait_until, +) +from test_framework.test_framework import BitcoinTestFramework +from test_framework.util import ( + assert_equal, + p2p_port, +) + +class P2PFingerprintTest(BitcoinTestFramework): + def set_test_params(self): + self.setup_clean_chain = True + self.num_nodes = 1 + + # 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 = NodeConnCB() + + connections = [] + connections.append(NodeConn('127.0.0.1', p2p_port(0), self.nodes[0], node0)) + node0.add_connection(connections[0]) + + NetworkThread().start() + node0.wait_for_verack() + + # 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() diff --git a/test/functional/test_framework/mininode.py b/test/functional/test_framework/mininode.py index d072969d7f..c6f596156a 100755 --- a/test/functional/test_framework/mininode.py +++ b/test/functional/test_framework/mininode.py @@ -1310,8 +1310,8 @@ class msg_getheaders(object): class msg_headers(object): command = b"headers" - def __init__(self): - self.headers = [] + def __init__(self, headers=None): + self.headers = headers if headers is not None else [] def deserialize(self, f): # comment in bitcoind indicates these should be deserialized as blocks diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py index 5c8740d7cd..434ba23b3b 100755 --- a/test/functional/test_runner.py +++ b/test/functional/test_runner.py @@ -123,6 +123,7 @@ BASE_SCRIPTS= [ 'uptime.py', 'resendwallettransactions.py', 'minchainwork.py', + 'p2p-fingerprint.py', ] EXTENDED_SCRIPTS = [ |