/workdir/bitcoin/src/signet.cpp
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1 | | // Copyright (c) 2019-2021 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 <signet.h> |
6 | | |
7 | | #include <array> |
8 | | #include <cstdint> |
9 | | #include <vector> |
10 | | |
11 | | #include <common/system.h> |
12 | | #include <consensus/merkle.h> |
13 | | #include <consensus/params.h> |
14 | | #include <consensus/validation.h> |
15 | | #include <core_io.h> |
16 | | #include <hash.h> |
17 | | #include <logging.h> |
18 | | #include <primitives/block.h> |
19 | | #include <primitives/transaction.h> |
20 | | #include <script/interpreter.h> |
21 | | #include <span.h> |
22 | | #include <streams.h> |
23 | | #include <uint256.h> |
24 | | #include <util/strencodings.h> |
25 | | |
26 | | static constexpr uint8_t SIGNET_HEADER[4] = {0xec, 0xc7, 0xda, 0xa2}; |
27 | | |
28 | | static constexpr unsigned int BLOCK_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_NULLDUMMY; |
29 | | |
30 | | static bool FetchAndClearCommitmentSection(const Span<const uint8_t> header, CScript& witness_commitment, std::vector<uint8_t>& result) |
31 | 0 | { |
32 | 0 | CScript replacement; |
33 | 0 | bool found_header = false; |
34 | 0 | result.clear(); |
35 | |
|
36 | 0 | opcodetype opcode; |
37 | 0 | CScript::const_iterator pc = witness_commitment.begin(); |
38 | 0 | std::vector<uint8_t> pushdata; |
39 | 0 | while (witness_commitment.GetOp(pc, opcode, pushdata)) { Branch (39:12): [True: 0, False: 0]
|
40 | 0 | if (pushdata.size() > 0) { Branch (40:13): [True: 0, False: 0]
|
41 | 0 | if (!found_header && pushdata.size() > (size_t)header.size() && Span{pushdata}.first(header.size()) == header) { Branch (41:17): [True: 0, False: 0]
Branch (41:17): [True: 0, False: 0]
Branch (41:34): [True: 0, False: 0]
Branch (41:77): [True: 0, False: 0]
|
42 | | // pushdata only counts if it has the header _and_ some data |
43 | 0 | result.insert(result.end(), pushdata.begin() + header.size(), pushdata.end()); |
44 | 0 | pushdata.erase(pushdata.begin() + header.size(), pushdata.end()); |
45 | 0 | found_header = true; |
46 | 0 | } |
47 | 0 | replacement << pushdata; |
48 | 0 | } else { |
49 | 0 | replacement << opcode; |
50 | 0 | } |
51 | 0 | } |
52 | |
|
53 | 0 | if (found_header) witness_commitment = replacement; Branch (53:9): [True: 0, False: 0]
|
54 | 0 | return found_header; |
55 | 0 | } |
56 | | |
57 | | static uint256 ComputeModifiedMerkleRoot(const CMutableTransaction& cb, const CBlock& block) |
58 | 0 | { |
59 | 0 | std::vector<uint256> leaves; |
60 | 0 | leaves.resize(block.vtx.size()); |
61 | 0 | leaves[0] = cb.GetHash(); |
62 | 0 | for (size_t s = 1; s < block.vtx.size(); ++s) { Branch (62:24): [True: 0, False: 0]
|
63 | 0 | leaves[s] = block.vtx[s]->GetHash(); |
64 | 0 | } |
65 | 0 | return ComputeMerkleRoot(std::move(leaves)); |
66 | 0 | } |
67 | | |
68 | | std::optional<SignetTxs> SignetTxs::Create(const CBlock& block, const CScript& challenge) |
69 | 0 | { |
70 | 0 | CMutableTransaction tx_to_spend; |
71 | 0 | tx_to_spend.version = 0; |
72 | 0 | tx_to_spend.nLockTime = 0; |
73 | 0 | tx_to_spend.vin.emplace_back(COutPoint(), CScript(OP_0), 0); |
74 | 0 | tx_to_spend.vout.emplace_back(0, challenge); |
75 | |
|
76 | 0 | CMutableTransaction tx_spending; |
77 | 0 | tx_spending.version = 0; |
78 | 0 | tx_spending.nLockTime = 0; |
79 | 0 | tx_spending.vin.emplace_back(COutPoint(), CScript(), 0); |
80 | 0 | tx_spending.vout.emplace_back(0, CScript(OP_RETURN)); |
81 | | |
82 | | // can't fill any other fields before extracting signet |
83 | | // responses from block coinbase tx |
84 | | |
85 | | // find and delete signet signature |
86 | 0 | if (block.vtx.empty()) return std::nullopt; // no coinbase tx in block; invalid Branch (86:9): [True: 0, False: 0]
|
87 | 0 | CMutableTransaction modified_cb(*block.vtx.at(0)); |
88 | |
|
89 | 0 | const int cidx = GetWitnessCommitmentIndex(block); |
90 | 0 | if (cidx == NO_WITNESS_COMMITMENT) { Branch (90:9): [True: 0, False: 0]
|
91 | 0 | return std::nullopt; // require a witness commitment |
92 | 0 | } |
93 | | |
94 | 0 | CScript& witness_commitment = modified_cb.vout.at(cidx).scriptPubKey; |
95 | |
|
96 | 0 | std::vector<uint8_t> signet_solution; |
97 | 0 | if (!FetchAndClearCommitmentSection(SIGNET_HEADER, witness_commitment, signet_solution)) { Branch (97:9): [True: 0, False: 0]
|
98 | | // no signet solution -- allow this to support OP_TRUE as trivial block challenge |
99 | 0 | } else { |
100 | 0 | try { |
101 | 0 | SpanReader v{signet_solution}; |
102 | 0 | v >> tx_spending.vin[0].scriptSig; |
103 | 0 | v >> tx_spending.vin[0].scriptWitness.stack; |
104 | 0 | if (!v.empty()) return std::nullopt; // extraneous data encountered Branch (104:17): [True: 0, False: 0]
|
105 | 0 | } catch (const std::exception&) { |
106 | 0 | return std::nullopt; // parsing error |
107 | 0 | } |
108 | 0 | } |
109 | 0 | uint256 signet_merkle = ComputeModifiedMerkleRoot(modified_cb, block); |
110 | |
|
111 | 0 | std::vector<uint8_t> block_data; |
112 | 0 | VectorWriter writer{block_data, 0}; |
113 | 0 | writer << block.nVersion; |
114 | 0 | writer << block.hashPrevBlock; |
115 | 0 | writer << signet_merkle; |
116 | 0 | writer << block.nTime; |
117 | 0 | tx_to_spend.vin[0].scriptSig << block_data; |
118 | 0 | tx_spending.vin[0].prevout = COutPoint(tx_to_spend.GetHash(), 0); |
119 | |
|
120 | 0 | return SignetTxs{tx_to_spend, tx_spending}; |
121 | 0 | } |
122 | | |
123 | | // Signet block solution checker |
124 | | bool CheckSignetBlockSolution(const CBlock& block, const Consensus::Params& consensusParams) |
125 | 0 | { |
126 | 0 | if (block.GetHash() == consensusParams.hashGenesisBlock) { Branch (126:9): [True: 0, False: 0]
|
127 | | // genesis block solution is always valid |
128 | 0 | return true; |
129 | 0 | } |
130 | | |
131 | 0 | const CScript challenge(consensusParams.signet_challenge.begin(), consensusParams.signet_challenge.end()); |
132 | 0 | const std::optional<SignetTxs> signet_txs = SignetTxs::Create(block, challenge); |
133 | |
|
134 | 0 | if (!signet_txs) { Branch (134:9): [True: 0, False: 0]
|
135 | 0 | LogPrint(BCLog::VALIDATION, "CheckSignetBlockSolution: Errors in block (block solution parse failure)\n"); |
136 | 0 | return false; |
137 | 0 | } |
138 | | |
139 | 0 | const CScript& scriptSig = signet_txs->m_to_sign.vin[0].scriptSig; |
140 | 0 | const CScriptWitness& witness = signet_txs->m_to_sign.vin[0].scriptWitness; |
141 | |
|
142 | 0 | PrecomputedTransactionData txdata; |
143 | 0 | txdata.Init(signet_txs->m_to_sign, {signet_txs->m_to_spend.vout[0]}); |
144 | 0 | TransactionSignatureChecker sigcheck(&signet_txs->m_to_sign, /* nInIn= */ 0, /* amountIn= */ signet_txs->m_to_spend.vout[0].nValue, txdata, MissingDataBehavior::ASSERT_FAIL); |
145 | |
|
146 | 0 | if (!VerifyScript(scriptSig, signet_txs->m_to_spend.vout[0].scriptPubKey, &witness, BLOCK_SCRIPT_VERIFY_FLAGS, sigcheck)) { Branch (146:9): [True: 0, False: 0]
|
147 | 0 | LogPrint(BCLog::VALIDATION, "CheckSignetBlockSolution: Errors in block (block solution invalid)\n"); |
148 | 0 | return false; |
149 | 0 | } |
150 | 0 | return true; |
151 | 0 | } |