1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
|
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <script/standard.h>
#include <pubkey.h>
#include <script/interpreter.h>
#include <script/script.h>
#include <span.h>
#include <string>
#include <algorithm>
typedef std::vector<unsigned char> valtype;
std::string GetTxnOutputType(TxoutType t)
{
switch (t) {
case TxoutType::NONSTANDARD: return "nonstandard";
case TxoutType::PUBKEY: return "pubkey";
case TxoutType::PUBKEYHASH: return "pubkeyhash";
case TxoutType::SCRIPTHASH: return "scripthash";
case TxoutType::MULTISIG: return "multisig";
case TxoutType::NULL_DATA: return "nulldata";
case TxoutType::WITNESS_V0_KEYHASH: return "witness_v0_keyhash";
case TxoutType::WITNESS_V0_SCRIPTHASH: return "witness_v0_scripthash";
case TxoutType::WITNESS_V1_TAPROOT: return "witness_v1_taproot";
case TxoutType::WITNESS_UNKNOWN: return "witness_unknown";
} // no default case, so the compiler can warn about missing cases
assert(false);
}
static bool MatchPayToPubkey(const CScript& script, valtype& pubkey)
{
if (script.size() == CPubKey::SIZE + 2 && script[0] == CPubKey::SIZE && script.back() == OP_CHECKSIG) {
pubkey = valtype(script.begin() + 1, script.begin() + CPubKey::SIZE + 1);
return CPubKey::ValidSize(pubkey);
}
if (script.size() == CPubKey::COMPRESSED_SIZE + 2 && script[0] == CPubKey::COMPRESSED_SIZE && script.back() == OP_CHECKSIG) {
pubkey = valtype(script.begin() + 1, script.begin() + CPubKey::COMPRESSED_SIZE + 1);
return CPubKey::ValidSize(pubkey);
}
return false;
}
static bool MatchPayToPubkeyHash(const CScript& script, valtype& pubkeyhash)
{
if (script.size() == 25 && script[0] == OP_DUP && script[1] == OP_HASH160 && script[2] == 20 && script[23] == OP_EQUALVERIFY && script[24] == OP_CHECKSIG) {
pubkeyhash = valtype(script.begin () + 3, script.begin() + 23);
return true;
}
return false;
}
/** Test for "small positive integer" script opcodes - OP_1 through OP_16. */
static constexpr bool IsSmallInteger(opcodetype opcode)
{
return opcode >= OP_1 && opcode <= OP_16;
}
/** Retrieve a minimally-encoded number in range [min,max] from an (opcode, data) pair,
* whether it's OP_n or through a push. */
static std::optional<int> GetScriptNumber(opcodetype opcode, valtype data, int min, int max)
{
int count;
if (IsSmallInteger(opcode)) {
count = CScript::DecodeOP_N(opcode);
} else if (IsPushdataOp(opcode)) {
if (!CheckMinimalPush(data, opcode)) return {};
try {
count = CScriptNum(data, /* fRequireMinimal = */ true).getint();
} catch (const scriptnum_error&) {
return {};
}
} else {
return {};
}
if (count < min || count > max) return {};
return count;
}
static bool MatchMultisig(const CScript& script, int& required_sigs, std::vector<valtype>& pubkeys)
{
opcodetype opcode;
valtype data;
CScript::const_iterator it = script.begin();
if (script.size() < 1 || script.back() != OP_CHECKMULTISIG) return false;
if (!script.GetOp(it, opcode, data)) return false;
auto req_sigs = GetScriptNumber(opcode, data, 1, MAX_PUBKEYS_PER_MULTISIG);
if (!req_sigs) return false;
required_sigs = *req_sigs;
while (script.GetOp(it, opcode, data) && CPubKey::ValidSize(data)) {
pubkeys.emplace_back(std::move(data));
}
auto num_keys = GetScriptNumber(opcode, data, required_sigs, MAX_PUBKEYS_PER_MULTISIG);
if (!num_keys) return false;
if (pubkeys.size() != static_cast<unsigned long>(*num_keys)) return false;
return (it + 1 == script.end());
}
std::optional<std::pair<int, std::vector<Span<const unsigned char>>>> MatchMultiA(const CScript& script)
{
std::vector<Span<const unsigned char>> keyspans;
// Redundant, but very fast and selective test.
if (script.size() == 0 || script[0] != 32 || script.back() != OP_NUMEQUAL) return {};
// Parse keys
auto it = script.begin();
while (script.end() - it >= 34) {
if (*it != 32) return {};
++it;
keyspans.emplace_back(&*it, 32);
it += 32;
if (*it != (keyspans.size() == 1 ? OP_CHECKSIG : OP_CHECKSIGADD)) return {};
++it;
}
if (keyspans.size() == 0 || keyspans.size() > MAX_PUBKEYS_PER_MULTI_A) return {};
// Parse threshold.
opcodetype opcode;
std::vector<unsigned char> data;
if (!script.GetOp(it, opcode, data)) return {};
if (it == script.end()) return {};
if (*it != OP_NUMEQUAL) return {};
++it;
if (it != script.end()) return {};
auto threshold = GetScriptNumber(opcode, data, 1, (int)keyspans.size());
if (!threshold) return {};
// Construct result.
return std::pair{*threshold, std::move(keyspans)};
}
TxoutType Solver(const CScript& scriptPubKey, std::vector<std::vector<unsigned char>>& vSolutionsRet)
{
vSolutionsRet.clear();
// Shortcut for pay-to-script-hash, which are more constrained than the other types:
// it is always OP_HASH160 20 [20 byte hash] OP_EQUAL
if (scriptPubKey.IsPayToScriptHash())
{
std::vector<unsigned char> hashBytes(scriptPubKey.begin()+2, scriptPubKey.begin()+22);
vSolutionsRet.push_back(hashBytes);
return TxoutType::SCRIPTHASH;
}
int witnessversion;
std::vector<unsigned char> witnessprogram;
if (scriptPubKey.IsWitnessProgram(witnessversion, witnessprogram)) {
if (witnessversion == 0 && witnessprogram.size() == WITNESS_V0_KEYHASH_SIZE) {
vSolutionsRet.push_back(std::move(witnessprogram));
return TxoutType::WITNESS_V0_KEYHASH;
}
if (witnessversion == 0 && witnessprogram.size() == WITNESS_V0_SCRIPTHASH_SIZE) {
vSolutionsRet.push_back(std::move(witnessprogram));
return TxoutType::WITNESS_V0_SCRIPTHASH;
}
if (witnessversion == 1 && witnessprogram.size() == WITNESS_V1_TAPROOT_SIZE) {
vSolutionsRet.push_back(std::move(witnessprogram));
return TxoutType::WITNESS_V1_TAPROOT;
}
if (witnessversion != 0) {
vSolutionsRet.push_back(std::vector<unsigned char>{(unsigned char)witnessversion});
vSolutionsRet.push_back(std::move(witnessprogram));
return TxoutType::WITNESS_UNKNOWN;
}
return TxoutType::NONSTANDARD;
}
// Provably prunable, data-carrying output
//
// So long as script passes the IsUnspendable() test and all but the first
// byte passes the IsPushOnly() test we don't care what exactly is in the
// script.
if (scriptPubKey.size() >= 1 && scriptPubKey[0] == OP_RETURN && scriptPubKey.IsPushOnly(scriptPubKey.begin()+1)) {
return TxoutType::NULL_DATA;
}
std::vector<unsigned char> data;
if (MatchPayToPubkey(scriptPubKey, data)) {
vSolutionsRet.push_back(std::move(data));
return TxoutType::PUBKEY;
}
if (MatchPayToPubkeyHash(scriptPubKey, data)) {
vSolutionsRet.push_back(std::move(data));
return TxoutType::PUBKEYHASH;
}
int required;
std::vector<std::vector<unsigned char>> keys;
if (MatchMultisig(scriptPubKey, required, keys)) {
vSolutionsRet.push_back({static_cast<unsigned char>(required)}); // safe as required is in range 1..20
vSolutionsRet.insert(vSolutionsRet.end(), keys.begin(), keys.end());
vSolutionsRet.push_back({static_cast<unsigned char>(keys.size())}); // safe as size is in range 1..20
return TxoutType::MULTISIG;
}
vSolutionsRet.clear();
return TxoutType::NONSTANDARD;
}
CScript GetScriptForRawPubKey(const CPubKey& pubKey)
{
return CScript() << std::vector<unsigned char>(pubKey.begin(), pubKey.end()) << OP_CHECKSIG;
}
CScript GetScriptForMultisig(int nRequired, const std::vector<CPubKey>& keys)
{
CScript script;
script << nRequired;
for (const CPubKey& key : keys)
script << ToByteVector(key);
script << keys.size() << OP_CHECKMULTISIG;
return script;
}
|
