p2p_headers_presync.cpp raw
1 // Copyright (c) 2024-present The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5 #include <arith_uint256.h>
6 #include <blockencodings.h>
7 #include <net.h>
8 #include <net_processing.h>
9 #include <netmessagemaker.h>
10 #include <node/peerman_args.h>
11 #include <test/fuzz/FuzzedDataProvider.h>
12 #include <test/fuzz/fuzz.h>
13 #include <test/fuzz/util.h>
14 #include <test/util/net.h>
15 #include <test/util/script.h>
16 #include <test/util/setup_common.h>
17 #include <test/util/time.h>
18 #include <uint256.h>
19 #include <validation.h>
20
21 namespace {
22 constexpr uint32_t FUZZ_MAX_HEADERS_RESULTS{16};
23
24 class HeadersSyncSetup : public TestingSetup
25 {
26 std::vector<CNode*> m_connections;
27
28 public:
29 HeadersSyncSetup(const ChainType chain_type, TestOpts opts) : TestingSetup(chain_type, opts)
30 {
31 PeerManager::Options peerman_opts;
32 node::ApplyArgsManOptions(*m_node.args, peerman_opts);
33 peerman_opts.max_headers_result = FUZZ_MAX_HEADERS_RESULTS;
34 // The peerman's rng is a global that is reused, so it will be reused
35 // and may cause non-determinism between runs. This may even influence
36 // the global RNG, because seeding may be done from the global one. For
37 // now, avoid it influencing the global RNG, and initialize it with a
38 // constant instead.
39 peerman_opts.deterministic_rng = true;
40 // No txs are relayed. Disable irrelevant and possibly
41 // non-deterministic code paths.
42 peerman_opts.ignore_incoming_txs = true;
43 m_node.peerman = PeerManager::make(*m_node.connman, *m_node.addrman,
44 m_node.banman.get(), *m_node.chainman,
45 *m_node.mempool, *m_node.warnings, peerman_opts);
46
47 CConnman::Options options;
48 options.m_msgproc = m_node.peerman.get();
49 m_node.connman->Init(options);
50 }
51
52 void ResetAndInitialize() EXCLUSIVE_LOCKS_REQUIRED(NetEventsInterface::g_msgproc_mutex);
53 void SendMessage(FuzzedDataProvider& fuzzed_data_provider, CSerializedNetMsg&& msg)
54 EXCLUSIVE_LOCKS_REQUIRED(NetEventsInterface::g_msgproc_mutex);
55 };
56
57 void HeadersSyncSetup::ResetAndInitialize()
58 {
59 m_connections.clear();
60 auto& connman = static_cast<ConnmanTestMsg&>(*m_node.connman);
61 connman.StopNodes();
62
63 static NodeId id{0};
64 std::vector<ConnectionType> conn_types = {
65 ConnectionType::OUTBOUND_FULL_RELAY,
66 ConnectionType::BLOCK_RELAY,
67 ConnectionType::INBOUND
68 };
69
70 for (auto conn_type : conn_types) {
71 CAddress addr{};
72 m_connections.push_back(new CNode(id++, nullptr, addr, 0, 0, addr, "", conn_type, false, 0));
73 CNode& p2p_node = *m_connections.back();
74
75 connman.Handshake(
76 /*node=*/p2p_node,
77 /*successfully_connected=*/true,
78 /*remote_services=*/ServiceFlags(NODE_NETWORK | NODE_WITNESS),
79 /*local_services=*/ServiceFlags(NODE_NETWORK | NODE_WITNESS),
80 /*version=*/PROTOCOL_VERSION,
81 /*relay_txs=*/true);
82
83 connman.AddTestNode(p2p_node);
84 }
85 }
86
87 void HeadersSyncSetup::SendMessage(FuzzedDataProvider& fuzzed_data_provider, CSerializedNetMsg&& msg)
88 {
89 auto& connman = static_cast<ConnmanTestMsg&>(*m_node.connman);
90 CNode& connection = *PickValue(fuzzed_data_provider, m_connections);
91
92 connman.FlushSendBuffer(connection);
93 (void)connman.ReceiveMsgFrom(connection, std::move(msg));
94 connection.fPauseSend = false;
95 try {
96 connman.ProcessMessagesOnce(connection);
97 } catch (const std::ios_base::failure&) {
98 }
99 m_node.peerman->SendMessages(connection);
100 }
101
102 CBlockHeader ConsumeHeader(FuzzedDataProvider& fuzzed_data_provider, const uint256& prev_hash, uint32_t prev_nbits)
103 {
104 CBlockHeader header;
105 header.nNonce = 0;
106 // Either use the previous difficulty or let the fuzzer choose. The upper target in the
107 // range comes from the bits value of the genesis block, which is 0x1d00ffff. The lower
108 // target comes from the bits value of mainnet block 840000, which is 0x17034219.
109 // Calling lower_target.SetCompact(0x17034219) and upper_target.SetCompact(0x1d00ffff)
110 // should return the values below.
111 //
112 // RPC commands to verify:
113 // getblockheader 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
114 // getblockheader 0000000000000000000320283a032748cef8227873ff4872689bf23f1cda83a5
115 if (fuzzed_data_provider.ConsumeBool()) {
116 header.nBits = prev_nbits;
117 } else {
118 arith_uint256 lower_target = UintToArith256(uint256{"0000000000000000000342190000000000000000000000000000000000000000"});
119 arith_uint256 upper_target = UintToArith256(uint256{"00000000ffff0000000000000000000000000000000000000000000000000000"});
120 arith_uint256 target = ConsumeArithUInt256InRange(fuzzed_data_provider, lower_target, upper_target);
121 header.nBits = target.GetCompact();
122 }
123 header.nTime = TicksSinceEpoch<std::chrono::seconds>(ConsumeTime(fuzzed_data_provider));
124 header.hashPrevBlock = prev_hash;
125 header.nVersion = fuzzed_data_provider.ConsumeIntegral<int32_t>();
126 return header;
127 }
128
129 CBlock ConsumeBlock(FuzzedDataProvider& fuzzed_data_provider, const uint256& prev_hash, uint32_t prev_nbits)
130 {
131 auto header = ConsumeHeader(fuzzed_data_provider, prev_hash, prev_nbits);
132 // In order to reach the headers acceptance logic, the block is
133 // constructed in a way that will pass the mutation checks.
134 CBlock block{header};
135 CMutableTransaction tx;
136 tx.vin.resize(1);
137 tx.vout.resize(1);
138 tx.vout[0].nValue = 0;
139 tx.vin[0].scriptSig.resize(2);
140 block.vtx.push_back(MakeTransactionRef(tx));
141 block.hashMerkleRoot = block.vtx[0]->GetHash().ToUint256();
142 return block;
143 }
144
145 // Global setup works for this test as state modification (specifically in the
146 // block index) would indicate a bug.
147 HeadersSyncSetup* g_testing_setup;
148
149 void initialize()
150 {
151 static auto setup{
152 MakeNoLogFileContext<HeadersSyncSetup>(ChainType::MAIN,
153 {
154 .setup_validation_interface = false,
155 }),
156 };
157 g_testing_setup = setup.get();
158 }
159 } // namespace
160
161 FUZZ_TARGET(p2p_headers_presync, .init = initialize)
162 {
163 SeedRandomStateForTest(SeedRand::ZEROS);
164 FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
165 // The steady clock is currently only used for logging, so a constant
166 // time-point seems acceptable for now.
167 FakeSteadyClock steady_ctx{};
168
169 ChainstateManager& chainman = *g_testing_setup->m_node.chainman;
170 CBlockHeader base{chainman.GetParams().GenesisBlock()};
171 const FakeNodeClock clock{base.Time()};
172
173 LOCK(NetEventsInterface::g_msgproc_mutex);
174
175 g_testing_setup->ResetAndInitialize();
176
177 // The chain is just a single block, so this is equal to 1
178 size_t original_index_size{WITH_LOCK(cs_main, return chainman.m_blockman.m_block_index.size())};
179 arith_uint256 total_work{WITH_LOCK(cs_main, return chainman.m_best_header->nChainWork)};
180
181 std::vector<CBlockHeader> all_headers;
182
183 LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 100)
184 {
185 auto finalized_block = [&]() {
186 CBlock block = ConsumeBlock(fuzzed_data_provider, base.GetHash(), base.nBits);
187 FinalizeHeader(block, chainman);
188 return block;
189 };
190
191 // Send low-work headers, compact blocks, and blocks
192 CallOneOf(
193 fuzzed_data_provider,
194 [&]() NO_THREAD_SAFETY_ANALYSIS {
195 // Send FUZZ_MAX_HEADERS_RESULTS headers
196 std::vector<CBlock> headers;
197 headers.resize(FUZZ_MAX_HEADERS_RESULTS);
198 for (CBlock& header : headers) {
199 header = ConsumeHeader(fuzzed_data_provider, base.GetHash(), base.nBits);
200 FinalizeHeader(header, chainman);
201 base = header;
202 }
203
204 all_headers.insert(all_headers.end(), headers.begin(), headers.end());
205
206 auto headers_msg = NetMsg::Make(NetMsgType::HEADERS, TX_WITH_WITNESS(headers));
207 g_testing_setup->SendMessage(fuzzed_data_provider, std::move(headers_msg));
208 },
209 [&]() NO_THREAD_SAFETY_ANALYSIS {
210 // Send a compact block
211 auto block = finalized_block();
212 CBlockHeaderAndShortTxIDs cmpct_block{block, fuzzed_data_provider.ConsumeIntegral<uint64_t>()};
213
214 all_headers.push_back(block);
215
216 auto headers_msg = NetMsg::Make(NetMsgType::CMPCTBLOCK, TX_WITH_WITNESS(cmpct_block));
217 g_testing_setup->SendMessage(fuzzed_data_provider, std::move(headers_msg));
218 },
219 [&]() NO_THREAD_SAFETY_ANALYSIS {
220 // Send a block
221 auto block = finalized_block();
222
223 all_headers.push_back(block);
224
225 auto headers_msg = NetMsg::Make(NetMsgType::BLOCK, TX_WITH_WITNESS(block));
226 g_testing_setup->SendMessage(fuzzed_data_provider, std::move(headers_msg));
227 });
228 }
229
230 // This is a conservative overestimate, as base is only moved forward when sending headers. In theory,
231 // the longest chain generated by this test is 1600 (FUZZ_MAX_HEADERS_RESULTS * 100) headers. In that case,
232 // this variable will accurately reflect the chain's total work.
233 total_work += CalculateClaimedHeadersWork(all_headers);
234
235 // This test should never create a chain with more work than MinimumChainWork.
236 assert(total_work < chainman.MinimumChainWork());
237
238 // The headers/blocks sent in this test should never be stored, as the chains don't have the work required
239 // to meet the anti-DoS work threshold. So, if at any point the block index grew in size, then there's a bug
240 // in the headers pre-sync logic.
241 assert(WITH_LOCK(cs_main, return chainman.m_blockman.m_block_index.size()) == original_index_size);
242 }
243