Line data Source code
1 : // Copyright (c) 2009-2010 Satoshi Nakamoto
2 : // Copyright (c) 2009-2022 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 :
6 : #include <script/sign.h>
7 :
8 : #include <consensus/amount.h>
9 : #include <key.h>
10 : #include <policy/policy.h>
11 : #include <primitives/transaction.h>
12 : #include <script/keyorigin.h>
13 : #include <script/miniscript.h>
14 : #include <script/script.h>
15 : #include <script/signingprovider.h>
16 : #include <script/solver.h>
17 : #include <uint256.h>
18 : #include <util/translation.h>
19 : #include <util/vector.h>
20 :
21 : typedef std::vector<unsigned char> valtype;
22 :
23 0 : MutableTransactionSignatureCreator::MutableTransactionSignatureCreator(const CMutableTransaction& tx, unsigned int input_idx, const CAmount& amount, int hash_type)
24 0 : : m_txto{tx}, nIn{input_idx}, nHashType{hash_type}, amount{amount}, checker{&m_txto, nIn, amount, MissingDataBehavior::FAIL},
25 0 : m_txdata(nullptr)
26 0 : {
27 0 : }
28 :
29 0 : MutableTransactionSignatureCreator::MutableTransactionSignatureCreator(const CMutableTransaction& tx, unsigned int input_idx, const CAmount& amount, const PrecomputedTransactionData* txdata, int hash_type)
30 0 : : m_txto{tx}, nIn{input_idx}, nHashType{hash_type}, amount{amount},
31 0 : checker{txdata ? MutableTransactionSignatureChecker{&m_txto, nIn, amount, *txdata, MissingDataBehavior::FAIL} :
32 0 : MutableTransactionSignatureChecker{&m_txto, nIn, amount, MissingDataBehavior::FAIL}},
33 0 : m_txdata(txdata)
34 0 : {
35 0 : }
36 :
37 0 : bool MutableTransactionSignatureCreator::CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& address, const CScript& scriptCode, SigVersion sigversion) const
38 : {
39 0 : assert(sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0);
40 :
41 0 : CKey key;
42 0 : if (!provider.GetKey(address, key))
43 0 : return false;
44 :
45 : // Signing with uncompressed keys is disabled in witness scripts
46 0 : if (sigversion == SigVersion::WITNESS_V0 && !key.IsCompressed())
47 0 : return false;
48 :
49 : // Signing without known amount does not work in witness scripts.
50 0 : if (sigversion == SigVersion::WITNESS_V0 && !MoneyRange(amount)) return false;
51 :
52 : // BASE/WITNESS_V0 signatures don't support explicit SIGHASH_DEFAULT, use SIGHASH_ALL instead.
53 0 : const int hashtype = nHashType == SIGHASH_DEFAULT ? SIGHASH_ALL : nHashType;
54 :
55 0 : uint256 hash = SignatureHash(scriptCode, m_txto, nIn, hashtype, amount, sigversion, m_txdata);
56 0 : if (!key.Sign(hash, vchSig))
57 0 : return false;
58 0 : vchSig.push_back((unsigned char)hashtype);
59 0 : return true;
60 0 : }
61 :
62 0 : bool MutableTransactionSignatureCreator::CreateSchnorrSig(const SigningProvider& provider, std::vector<unsigned char>& sig, const XOnlyPubKey& pubkey, const uint256* leaf_hash, const uint256* merkle_root, SigVersion sigversion) const
63 : {
64 0 : assert(sigversion == SigVersion::TAPROOT || sigversion == SigVersion::TAPSCRIPT);
65 :
66 0 : CKey key;
67 0 : if (!provider.GetKeyByXOnly(pubkey, key)) return false;
68 :
69 : // BIP341/BIP342 signing needs lots of precomputed transaction data. While some
70 : // (non-SIGHASH_DEFAULT) sighash modes exist that can work with just some subset
71 : // of data present, for now, only support signing when everything is provided.
72 0 : if (!m_txdata || !m_txdata->m_bip341_taproot_ready || !m_txdata->m_spent_outputs_ready) return false;
73 :
74 2 : ScriptExecutionData execdata;
75 0 : execdata.m_annex_init = true;
76 0 : execdata.m_annex_present = false; // Only support annex-less signing for now.
77 0 : if (sigversion == SigVersion::TAPSCRIPT) {
78 0 : execdata.m_codeseparator_pos_init = true;
79 0 : execdata.m_codeseparator_pos = 0xFFFFFFFF; // Only support non-OP_CODESEPARATOR BIP342 signing for now.
80 0 : if (!leaf_hash) return false; // BIP342 signing needs leaf hash.
81 0 : execdata.m_tapleaf_hash_init = true;
82 0 : execdata.m_tapleaf_hash = *leaf_hash;
83 0 : }
84 0 : uint256 hash;
85 0 : if (!SignatureHashSchnorr(hash, execdata, m_txto, nIn, nHashType, sigversion, *m_txdata, MissingDataBehavior::FAIL)) return false;
86 0 : sig.resize(64);
87 : // Use uint256{} as aux_rnd for now.
88 0 : if (!key.SignSchnorr(hash, sig, merkle_root, {})) return false;
89 0 : if (nHashType) sig.push_back(nHashType);
90 0 : return true;
91 0 : }
92 :
93 0 : static bool GetCScript(const SigningProvider& provider, const SignatureData& sigdata, const CScriptID& scriptid, CScript& script)
94 : {
95 0 : if (provider.GetCScript(scriptid, script)) {
96 0 : return true;
97 : }
98 : // Look for scripts in SignatureData
99 0 : if (CScriptID(sigdata.redeem_script) == scriptid) {
100 0 : script = sigdata.redeem_script;
101 0 : return true;
102 0 : } else if (CScriptID(sigdata.witness_script) == scriptid) {
103 0 : script = sigdata.witness_script;
104 0 : return true;
105 : }
106 0 : return false;
107 0 : }
108 :
109 0 : static bool GetPubKey(const SigningProvider& provider, const SignatureData& sigdata, const CKeyID& address, CPubKey& pubkey)
110 : {
111 : // Look for pubkey in all partial sigs
112 0 : const auto it = sigdata.signatures.find(address);
113 0 : if (it != sigdata.signatures.end()) {
114 0 : pubkey = it->second.first;
115 0 : return true;
116 : }
117 : // Look for pubkey in pubkey list
118 0 : const auto& pk_it = sigdata.misc_pubkeys.find(address);
119 0 : if (pk_it != sigdata.misc_pubkeys.end()) {
120 0 : pubkey = pk_it->second.first;
121 0 : return true;
122 : }
123 : // Query the underlying provider
124 0 : return provider.GetPubKey(address, pubkey);
125 0 : }
126 :
127 0 : static bool CreateSig(const BaseSignatureCreator& creator, SignatureData& sigdata, const SigningProvider& provider, std::vector<unsigned char>& sig_out, const CPubKey& pubkey, const CScript& scriptcode, SigVersion sigversion)
128 : {
129 0 : CKeyID keyid = pubkey.GetID();
130 0 : const auto it = sigdata.signatures.find(keyid);
131 0 : if (it != sigdata.signatures.end()) {
132 0 : sig_out = it->second.second;
133 0 : return true;
134 : }
135 0 : KeyOriginInfo info;
136 0 : if (provider.GetKeyOrigin(keyid, info)) {
137 0 : sigdata.misc_pubkeys.emplace(keyid, std::make_pair(pubkey, std::move(info)));
138 0 : }
139 0 : if (creator.CreateSig(provider, sig_out, keyid, scriptcode, sigversion)) {
140 0 : auto i = sigdata.signatures.emplace(keyid, SigPair(pubkey, sig_out));
141 0 : assert(i.second);
142 0 : return true;
143 : }
144 : // Could not make signature or signature not found, add keyid to missing
145 0 : sigdata.missing_sigs.push_back(keyid);
146 0 : return false;
147 0 : }
148 :
149 0 : static bool CreateTaprootScriptSig(const BaseSignatureCreator& creator, SignatureData& sigdata, const SigningProvider& provider, std::vector<unsigned char>& sig_out, const XOnlyPubKey& pubkey, const uint256& leaf_hash, SigVersion sigversion)
150 : {
151 0 : KeyOriginInfo info;
152 0 : if (provider.GetKeyOriginByXOnly(pubkey, info)) {
153 0 : auto it = sigdata.taproot_misc_pubkeys.find(pubkey);
154 0 : if (it == sigdata.taproot_misc_pubkeys.end()) {
155 0 : sigdata.taproot_misc_pubkeys.emplace(pubkey, std::make_pair(std::set<uint256>({leaf_hash}), info));
156 0 : } else {
157 0 : it->second.first.insert(leaf_hash);
158 : }
159 0 : }
160 :
161 0 : auto lookup_key = std::make_pair(pubkey, leaf_hash);
162 0 : auto it = sigdata.taproot_script_sigs.find(lookup_key);
163 0 : if (it != sigdata.taproot_script_sigs.end()) {
164 0 : sig_out = it->second;
165 0 : return true;
166 : }
167 0 : if (creator.CreateSchnorrSig(provider, sig_out, pubkey, &leaf_hash, nullptr, sigversion)) {
168 0 : sigdata.taproot_script_sigs[lookup_key] = sig_out;
169 0 : return true;
170 : }
171 0 : return false;
172 0 : }
173 :
174 0 : static bool SignTaprootScript(const SigningProvider& provider, const BaseSignatureCreator& creator, SignatureData& sigdata, int leaf_version, Span<const unsigned char> script_bytes, std::vector<valtype>& result)
175 : {
176 : // Only BIP342 tapscript signing is supported for now.
177 0 : if (leaf_version != TAPROOT_LEAF_TAPSCRIPT) return false;
178 0 : SigVersion sigversion = SigVersion::TAPSCRIPT;
179 :
180 0 : uint256 leaf_hash = ComputeTapleafHash(leaf_version, script_bytes);
181 0 : CScript script = CScript(script_bytes.begin(), script_bytes.end());
182 :
183 : // <xonly pubkey> OP_CHECKSIG
184 0 : if (script.size() == 34 && script[33] == OP_CHECKSIG && script[0] == 0x20) {
185 0 : XOnlyPubKey pubkey{Span{script}.subspan(1, 32)};
186 0 : std::vector<unsigned char> sig;
187 0 : if (CreateTaprootScriptSig(creator, sigdata, provider, sig, pubkey, leaf_hash, sigversion)) {
188 0 : result = Vector(std::move(sig));
189 0 : return true;
190 : }
191 0 : return false;
192 0 : }
193 :
194 : // multi_a scripts (<key> OP_CHECKSIG <key> OP_CHECKSIGADD <key> OP_CHECKSIGADD <k> OP_NUMEQUAL)
195 0 : if (auto match = MatchMultiA(script)) {
196 0 : std::vector<std::vector<unsigned char>> sigs;
197 0 : int good_sigs = 0;
198 0 : for (size_t i = 0; i < match->second.size(); ++i) {
199 0 : XOnlyPubKey pubkey{*(match->second.rbegin() + i)};
200 0 : std::vector<unsigned char> sig;
201 0 : bool good_sig = CreateTaprootScriptSig(creator, sigdata, provider, sig, pubkey, leaf_hash, sigversion);
202 0 : if (good_sig && good_sigs < match->first) {
203 0 : ++good_sigs;
204 0 : sigs.push_back(std::move(sig));
205 0 : } else {
206 0 : sigs.emplace_back();
207 : }
208 0 : }
209 0 : if (good_sigs == match->first) {
210 0 : result = std::move(sigs);
211 0 : return true;
212 : }
213 0 : return false;
214 0 : }
215 :
216 0 : return false;
217 0 : }
218 :
219 0 : static bool SignTaproot(const SigningProvider& provider, const BaseSignatureCreator& creator, const WitnessV1Taproot& output, SignatureData& sigdata, std::vector<valtype>& result)
220 : {
221 0 : TaprootSpendData spenddata;
222 0 : TaprootBuilder builder;
223 :
224 : // Gather information about this output.
225 0 : if (provider.GetTaprootSpendData(output, spenddata)) {
226 0 : sigdata.tr_spenddata.Merge(spenddata);
227 0 : }
228 0 : if (provider.GetTaprootBuilder(output, builder)) {
229 0 : sigdata.tr_builder = builder;
230 0 : }
231 :
232 : // Try key path spending.
233 : {
234 0 : KeyOriginInfo info;
235 0 : if (provider.GetKeyOriginByXOnly(sigdata.tr_spenddata.internal_key, info)) {
236 0 : auto it = sigdata.taproot_misc_pubkeys.find(sigdata.tr_spenddata.internal_key);
237 0 : if (it == sigdata.taproot_misc_pubkeys.end()) {
238 0 : sigdata.taproot_misc_pubkeys.emplace(sigdata.tr_spenddata.internal_key, std::make_pair(std::set<uint256>(), info));
239 0 : }
240 0 : }
241 :
242 0 : std::vector<unsigned char> sig;
243 0 : if (sigdata.taproot_key_path_sig.size() == 0) {
244 0 : if (creator.CreateSchnorrSig(provider, sig, sigdata.tr_spenddata.internal_key, nullptr, &sigdata.tr_spenddata.merkle_root, SigVersion::TAPROOT)) {
245 0 : sigdata.taproot_key_path_sig = sig;
246 0 : }
247 0 : }
248 0 : if (sigdata.taproot_key_path_sig.size() == 0) {
249 0 : if (creator.CreateSchnorrSig(provider, sig, output, nullptr, nullptr, SigVersion::TAPROOT)) {
250 0 : sigdata.taproot_key_path_sig = sig;
251 0 : }
252 0 : }
253 0 : if (sigdata.taproot_key_path_sig.size()) {
254 0 : result = Vector(sigdata.taproot_key_path_sig);
255 0 : return true;
256 : }
257 0 : }
258 :
259 : // Try script path spending.
260 0 : std::vector<std::vector<unsigned char>> smallest_result_stack;
261 0 : for (const auto& [key, control_blocks] : sigdata.tr_spenddata.scripts) {
262 0 : const auto& [script, leaf_ver] = key;
263 0 : std::vector<std::vector<unsigned char>> result_stack;
264 0 : if (SignTaprootScript(provider, creator, sigdata, leaf_ver, script, result_stack)) {
265 0 : result_stack.emplace_back(std::begin(script), std::end(script)); // Push the script
266 0 : result_stack.push_back(*control_blocks.begin()); // Push the smallest control block
267 0 : if (smallest_result_stack.size() == 0 ||
268 0 : GetSerializeSize(result_stack, PROTOCOL_VERSION) < GetSerializeSize(smallest_result_stack, PROTOCOL_VERSION)) {
269 0 : smallest_result_stack = std::move(result_stack);
270 0 : }
271 0 : }
272 0 : }
273 0 : if (smallest_result_stack.size() != 0) {
274 0 : result = std::move(smallest_result_stack);
275 0 : return true;
276 : }
277 :
278 0 : return false;
279 0 : }
280 :
281 2 : /**
282 : * Sign scriptPubKey using signature made with creator.
283 2 : * Signatures are returned in scriptSigRet (or returns false if scriptPubKey can't be signed),
284 : * unless whichTypeRet is TxoutType::SCRIPTHASH, in which case scriptSigRet is the redemption script.
285 2 : * Returns false if scriptPubKey could not be completely satisfied.
286 : */
287 2 : static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator& creator, const CScript& scriptPubKey,
288 : std::vector<valtype>& ret, TxoutType& whichTypeRet, SigVersion sigversion, SignatureData& sigdata)
289 2 : {
290 0 : CScript scriptRet;
291 0 : ret.clear();
292 0 : std::vector<unsigned char> sig;
293 :
294 0 : std::vector<valtype> vSolutions;
295 0 : whichTypeRet = Solver(scriptPubKey, vSolutions);
296 :
297 0 : switch (whichTypeRet) {
298 : case TxoutType::NONSTANDARD:
299 : case TxoutType::NULL_DATA:
300 : case TxoutType::WITNESS_UNKNOWN:
301 0 : return false;
302 : case TxoutType::PUBKEY:
303 0 : if (!CreateSig(creator, sigdata, provider, sig, CPubKey(vSolutions[0]), scriptPubKey, sigversion)) return false;
304 0 : ret.push_back(std::move(sig));
305 0 : return true;
306 : case TxoutType::PUBKEYHASH: {
307 0 : CKeyID keyID = CKeyID(uint160(vSolutions[0]));
308 0 : CPubKey pubkey;
309 0 : if (!GetPubKey(provider, sigdata, keyID, pubkey)) {
310 : // Pubkey could not be found, add to missing
311 0 : sigdata.missing_pubkeys.push_back(keyID);
312 0 : return false;
313 : }
314 0 : if (!CreateSig(creator, sigdata, provider, sig, pubkey, scriptPubKey, sigversion)) return false;
315 0 : ret.push_back(std::move(sig));
316 0 : ret.push_back(ToByteVector(pubkey));
317 0 : return true;
318 : }
319 : case TxoutType::SCRIPTHASH: {
320 0 : uint160 h160{vSolutions[0]};
321 0 : if (GetCScript(provider, sigdata, CScriptID{h160}, scriptRet)) {
322 0 : ret.push_back(std::vector<unsigned char>(scriptRet.begin(), scriptRet.end()));
323 0 : return true;
324 : }
325 : // Could not find redeemScript, add to missing
326 0 : sigdata.missing_redeem_script = h160;
327 0 : return false;
328 : }
329 : case TxoutType::MULTISIG: {
330 0 : size_t required = vSolutions.front()[0];
331 0 : ret.push_back(valtype()); // workaround CHECKMULTISIG bug
332 0 : for (size_t i = 1; i < vSolutions.size() - 1; ++i) {
333 0 : CPubKey pubkey = CPubKey(vSolutions[i]);
334 : // We need to always call CreateSig in order to fill sigdata with all
335 : // possible signatures that we can create. This will allow further PSBT
336 : // processing to work as it needs all possible signature and pubkey pairs
337 0 : if (CreateSig(creator, sigdata, provider, sig, pubkey, scriptPubKey, sigversion)) {
338 0 : if (ret.size() < required + 1) {
339 0 : ret.push_back(std::move(sig));
340 0 : }
341 0 : }
342 0 : }
343 0 : bool ok = ret.size() == required + 1;
344 0 : for (size_t i = 0; i + ret.size() < required + 1; ++i) {
345 0 : ret.push_back(valtype());
346 0 : }
347 0 : return ok;
348 : }
349 : case TxoutType::WITNESS_V0_KEYHASH:
350 0 : ret.push_back(vSolutions[0]);
351 0 : return true;
352 :
353 : case TxoutType::WITNESS_V0_SCRIPTHASH:
354 0 : if (GetCScript(provider, sigdata, CScriptID{RIPEMD160(vSolutions[0])}, scriptRet)) {
355 0 : ret.push_back(std::vector<unsigned char>(scriptRet.begin(), scriptRet.end()));
356 0 : return true;
357 : }
358 : // Could not find witnessScript, add to missing
359 0 : sigdata.missing_witness_script = uint256(vSolutions[0]);
360 0 : return false;
361 :
362 : case TxoutType::WITNESS_V1_TAPROOT:
363 0 : return SignTaproot(provider, creator, WitnessV1Taproot(XOnlyPubKey{vSolutions[0]}), sigdata, ret);
364 : } // no default case, so the compiler can warn about missing cases
365 0 : assert(false);
366 0 : }
367 :
368 0 : static CScript PushAll(const std::vector<valtype>& values)
369 : {
370 0 : CScript result;
371 0 : for (const valtype& v : values) {
372 0 : if (v.size() == 0) {
373 0 : result << OP_0;
374 0 : } else if (v.size() == 1 && v[0] >= 1 && v[0] <= 16) {
375 0 : result << CScript::EncodeOP_N(v[0]);
376 0 : } else if (v.size() == 1 && v[0] == 0x81) {
377 0 : result << OP_1NEGATE;
378 0 : } else {
379 0 : result << v;
380 : }
381 : }
382 0 : return result;
383 0 : }
384 :
385 : template<typename M, typename K, typename V>
386 0 : miniscript::Availability MsLookupHelper(const M& map, const K& key, V& value)
387 : {
388 0 : auto it = map.find(key);
389 0 : if (it != map.end()) {
390 0 : value = it->second;
391 0 : return miniscript::Availability::YES;
392 : }
393 0 : return miniscript::Availability::NO;
394 0 : }
395 :
396 : /**
397 : * Context for solving a Miniscript.
398 : * If enough material (access to keys, hash preimages, ..) is given, produces a valid satisfaction.
399 : */
400 : struct Satisfier {
401 : typedef CPubKey Key;
402 :
403 : const SigningProvider& m_provider;
404 : SignatureData& m_sig_data;
405 : const BaseSignatureCreator& m_creator;
406 : const CScript& m_witness_script;
407 :
408 0 : explicit Satisfier(const SigningProvider& provider LIFETIMEBOUND, SignatureData& sig_data LIFETIMEBOUND,
409 : const BaseSignatureCreator& creator LIFETIMEBOUND,
410 0 : const CScript& witscript LIFETIMEBOUND) : m_provider(provider),
411 0 : m_sig_data(sig_data),
412 0 : m_creator(creator),
413 0 : m_witness_script(witscript) {}
414 :
415 0 : static bool KeyCompare(const Key& a, const Key& b) {
416 0 : return a < b;
417 : }
418 :
419 : //! Conversion from a raw public key.
420 : template <typename I>
421 0 : std::optional<Key> FromPKBytes(I first, I last) const
422 : {
423 0 : Key pubkey{first, last};
424 0 : if (pubkey.IsValid()) return pubkey;
425 0 : return {};
426 0 : }
427 :
428 : //! Conversion from a raw public key hash.
429 : template<typename I>
430 0 : std::optional<Key> FromPKHBytes(I first, I last) const {
431 0 : assert(last - first == 20);
432 0 : Key pubkey;
433 0 : CKeyID key_id;
434 0 : std::copy(first, last, key_id.begin());
435 0 : if (GetPubKey(m_provider, m_sig_data, key_id, pubkey)) return pubkey;
436 0 : m_sig_data.missing_pubkeys.push_back(key_id);
437 0 : return {};
438 0 : }
439 :
440 : //! Conversion to raw public key.
441 0 : std::vector<unsigned char> ToPKBytes(const CPubKey& key) const { return {key.begin(), key.end()}; }
442 :
443 : //! Satisfy a signature check.
444 0 : miniscript::Availability Sign(const CPubKey& key, std::vector<unsigned char>& sig) const {
445 0 : if (CreateSig(m_creator, m_sig_data, m_provider, sig, key, m_witness_script, SigVersion::WITNESS_V0)) {
446 0 : return miniscript::Availability::YES;
447 : }
448 0 : return miniscript::Availability::NO;
449 0 : }
450 :
451 : //! Time lock satisfactions.
452 0 : bool CheckAfter(uint32_t value) const { return m_creator.Checker().CheckLockTime(CScriptNum(value)); }
453 0 : bool CheckOlder(uint32_t value) const { return m_creator.Checker().CheckSequence(CScriptNum(value)); }
454 :
455 :
456 : //! Hash preimage satisfactions.
457 0 : miniscript::Availability SatSHA256(const std::vector<unsigned char>& hash, std::vector<unsigned char>& preimage) const {
458 0 : return MsLookupHelper(m_sig_data.sha256_preimages, hash, preimage);
459 : }
460 0 : miniscript::Availability SatRIPEMD160(const std::vector<unsigned char>& hash, std::vector<unsigned char>& preimage) const {
461 0 : return MsLookupHelper(m_sig_data.ripemd160_preimages, hash, preimage);
462 : }
463 0 : miniscript::Availability SatHASH256(const std::vector<unsigned char>& hash, std::vector<unsigned char>& preimage) const {
464 0 : return MsLookupHelper(m_sig_data.hash256_preimages, hash, preimage);
465 : }
466 0 : miniscript::Availability SatHASH160(const std::vector<unsigned char>& hash, std::vector<unsigned char>& preimage) const {
467 0 : return MsLookupHelper(m_sig_data.hash160_preimages, hash, preimage);
468 : }
469 : };
470 :
471 0 : bool ProduceSignature(const SigningProvider& provider, const BaseSignatureCreator& creator, const CScript& fromPubKey, SignatureData& sigdata)
472 : {
473 0 : if (sigdata.complete) return true;
474 :
475 0 : std::vector<valtype> result;
476 : TxoutType whichType;
477 0 : bool solved = SignStep(provider, creator, fromPubKey, result, whichType, SigVersion::BASE, sigdata);
478 0 : bool P2SH = false;
479 0 : CScript subscript;
480 :
481 0 : if (solved && whichType == TxoutType::SCRIPTHASH)
482 : {
483 : // Solver returns the subscript that needs to be evaluated;
484 : // the final scriptSig is the signatures from that
485 : // and then the serialized subscript:
486 0 : subscript = CScript(result[0].begin(), result[0].end());
487 0 : sigdata.redeem_script = subscript;
488 0 : solved = solved && SignStep(provider, creator, subscript, result, whichType, SigVersion::BASE, sigdata) && whichType != TxoutType::SCRIPTHASH;
489 0 : P2SH = true;
490 0 : }
491 :
492 0 : if (solved && whichType == TxoutType::WITNESS_V0_KEYHASH)
493 : {
494 0 : CScript witnessscript;
495 0 : witnessscript << OP_DUP << OP_HASH160 << ToByteVector(result[0]) << OP_EQUALVERIFY << OP_CHECKSIG;
496 : TxoutType subType;
497 0 : solved = solved && SignStep(provider, creator, witnessscript, result, subType, SigVersion::WITNESS_V0, sigdata);
498 0 : sigdata.scriptWitness.stack = result;
499 0 : sigdata.witness = true;
500 0 : result.clear();
501 0 : }
502 0 : else if (solved && whichType == TxoutType::WITNESS_V0_SCRIPTHASH)
503 : {
504 0 : CScript witnessscript(result[0].begin(), result[0].end());
505 0 : sigdata.witness_script = witnessscript;
506 :
507 0 : TxoutType subType{TxoutType::NONSTANDARD};
508 0 : solved = solved && SignStep(provider, creator, witnessscript, result, subType, SigVersion::WITNESS_V0, sigdata) && subType != TxoutType::SCRIPTHASH && subType != TxoutType::WITNESS_V0_SCRIPTHASH && subType != TxoutType::WITNESS_V0_KEYHASH;
509 :
510 : // If we couldn't find a solution with the legacy satisfier, try satisfying the script using Miniscript.
511 : // Note we need to check if the result stack is empty before, because it might be used even if the Script
512 : // isn't fully solved. For instance the CHECKMULTISIG satisfaction in SignStep() pushes partial signatures
513 : // and the extractor relies on this behaviour to combine witnesses.
514 0 : if (!solved && result.empty()) {
515 0 : Satisfier ms_satisfier{provider, sigdata, creator, witnessscript};
516 0 : const auto ms = miniscript::FromScript(witnessscript, ms_satisfier);
517 0 : solved = ms && ms->Satisfy(ms_satisfier, result) == miniscript::Availability::YES;
518 0 : }
519 0 : result.push_back(std::vector<unsigned char>(witnessscript.begin(), witnessscript.end()));
520 :
521 0 : sigdata.scriptWitness.stack = result;
522 0 : sigdata.witness = true;
523 0 : result.clear();
524 0 : } else if (whichType == TxoutType::WITNESS_V1_TAPROOT && !P2SH) {
525 0 : sigdata.witness = true;
526 0 : if (solved) {
527 0 : sigdata.scriptWitness.stack = std::move(result);
528 0 : }
529 0 : result.clear();
530 0 : } else if (solved && whichType == TxoutType::WITNESS_UNKNOWN) {
531 0 : sigdata.witness = true;
532 0 : }
533 :
534 0 : if (!sigdata.witness) sigdata.scriptWitness.stack.clear();
535 0 : if (P2SH) {
536 0 : result.push_back(std::vector<unsigned char>(subscript.begin(), subscript.end()));
537 0 : }
538 0 : sigdata.scriptSig = PushAll(result);
539 :
540 : // Test solution
541 0 : sigdata.complete = solved && VerifyScript(sigdata.scriptSig, fromPubKey, &sigdata.scriptWitness, STANDARD_SCRIPT_VERIFY_FLAGS, creator.Checker());
542 0 : return sigdata.complete;
543 0 : }
544 :
545 : namespace {
546 : class SignatureExtractorChecker final : public DeferringSignatureChecker
547 : {
548 : private:
549 : SignatureData& sigdata;
550 :
551 : public:
552 0 : SignatureExtractorChecker(SignatureData& sigdata, BaseSignatureChecker& checker) : DeferringSignatureChecker(checker), sigdata(sigdata) {}
553 :
554 0 : bool CheckECDSASignature(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const override
555 : {
556 0 : if (m_checker.CheckECDSASignature(scriptSig, vchPubKey, scriptCode, sigversion)) {
557 0 : CPubKey pubkey(vchPubKey);
558 0 : sigdata.signatures.emplace(pubkey.GetID(), SigPair(pubkey, scriptSig));
559 0 : return true;
560 : }
561 0 : return false;
562 0 : }
563 : };
564 :
565 : struct Stacks
566 : {
567 : std::vector<valtype> script;
568 : std::vector<valtype> witness;
569 :
570 : Stacks() = delete;
571 : Stacks(const Stacks&) = delete;
572 0 : explicit Stacks(const SignatureData& data) : witness(data.scriptWitness.stack) {
573 0 : EvalScript(script, data.scriptSig, SCRIPT_VERIFY_STRICTENC, BaseSignatureChecker(), SigVersion::BASE);
574 0 : }
575 : };
576 : }
577 :
578 : // Extracts signatures and scripts from incomplete scriptSigs. Please do not extend this, use PSBT instead
579 0 : SignatureData DataFromTransaction(const CMutableTransaction& tx, unsigned int nIn, const CTxOut& txout)
580 : {
581 0 : SignatureData data;
582 0 : assert(tx.vin.size() > nIn);
583 0 : data.scriptSig = tx.vin[nIn].scriptSig;
584 0 : data.scriptWitness = tx.vin[nIn].scriptWitness;
585 0 : Stacks stack(data);
586 :
587 : // Get signatures
588 0 : MutableTransactionSignatureChecker tx_checker(&tx, nIn, txout.nValue, MissingDataBehavior::FAIL);
589 0 : SignatureExtractorChecker extractor_checker(data, tx_checker);
590 0 : if (VerifyScript(data.scriptSig, txout.scriptPubKey, &data.scriptWitness, STANDARD_SCRIPT_VERIFY_FLAGS, extractor_checker)) {
591 0 : data.complete = true;
592 0 : return data;
593 : }
594 :
595 : // Get scripts
596 0 : std::vector<std::vector<unsigned char>> solutions;
597 0 : TxoutType script_type = Solver(txout.scriptPubKey, solutions);
598 0 : SigVersion sigversion = SigVersion::BASE;
599 0 : CScript next_script = txout.scriptPubKey;
600 :
601 0 : if (script_type == TxoutType::SCRIPTHASH && !stack.script.empty() && !stack.script.back().empty()) {
602 : // Get the redeemScript
603 0 : CScript redeem_script(stack.script.back().begin(), stack.script.back().end());
604 0 : data.redeem_script = redeem_script;
605 0 : next_script = std::move(redeem_script);
606 :
607 : // Get redeemScript type
608 0 : script_type = Solver(next_script, solutions);
609 0 : stack.script.pop_back();
610 0 : }
611 0 : if (script_type == TxoutType::WITNESS_V0_SCRIPTHASH && !stack.witness.empty() && !stack.witness.back().empty()) {
612 : // Get the witnessScript
613 0 : CScript witness_script(stack.witness.back().begin(), stack.witness.back().end());
614 0 : data.witness_script = witness_script;
615 0 : next_script = std::move(witness_script);
616 :
617 : // Get witnessScript type
618 0 : script_type = Solver(next_script, solutions);
619 0 : stack.witness.pop_back();
620 0 : stack.script = std::move(stack.witness);
621 0 : stack.witness.clear();
622 0 : sigversion = SigVersion::WITNESS_V0;
623 0 : }
624 0 : if (script_type == TxoutType::MULTISIG && !stack.script.empty()) {
625 : // Build a map of pubkey -> signature by matching sigs to pubkeys:
626 0 : assert(solutions.size() > 1);
627 0 : unsigned int num_pubkeys = solutions.size()-2;
628 0 : unsigned int last_success_key = 0;
629 0 : for (const valtype& sig : stack.script) {
630 0 : for (unsigned int i = last_success_key; i < num_pubkeys; ++i) {
631 0 : const valtype& pubkey = solutions[i+1];
632 : // We either have a signature for this pubkey, or we have found a signature and it is valid
633 0 : if (data.signatures.count(CPubKey(pubkey).GetID()) || extractor_checker.CheckECDSASignature(sig, pubkey, next_script, sigversion)) {
634 0 : last_success_key = i + 1;
635 0 : break;
636 : }
637 0 : }
638 : }
639 0 : }
640 :
641 0 : return data;
642 0 : }
643 :
644 0 : void UpdateInput(CTxIn& input, const SignatureData& data)
645 : {
646 0 : input.scriptSig = data.scriptSig;
647 0 : input.scriptWitness = data.scriptWitness;
648 0 : }
649 :
650 0 : void SignatureData::MergeSignatureData(SignatureData sigdata)
651 : {
652 0 : if (complete) return;
653 0 : if (sigdata.complete) {
654 0 : *this = std::move(sigdata);
655 0 : return;
656 : }
657 0 : if (redeem_script.empty() && !sigdata.redeem_script.empty()) {
658 0 : redeem_script = sigdata.redeem_script;
659 0 : }
660 0 : if (witness_script.empty() && !sigdata.witness_script.empty()) {
661 0 : witness_script = sigdata.witness_script;
662 0 : }
663 0 : signatures.insert(std::make_move_iterator(sigdata.signatures.begin()), std::make_move_iterator(sigdata.signatures.end()));
664 0 : }
665 :
666 0 : bool SignSignature(const SigningProvider &provider, const CScript& fromPubKey, CMutableTransaction& txTo, unsigned int nIn, const CAmount& amount, int nHashType, SignatureData& sig_data)
667 : {
668 0 : assert(nIn < txTo.vin.size());
669 :
670 0 : MutableTransactionSignatureCreator creator(txTo, nIn, amount, nHashType);
671 :
672 0 : bool ret = ProduceSignature(provider, creator, fromPubKey, sig_data);
673 0 : UpdateInput(txTo.vin.at(nIn), sig_data);
674 0 : return ret;
675 0 : }
676 :
677 0 : bool SignSignature(const SigningProvider &provider, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType, SignatureData& sig_data)
678 : {
679 0 : assert(nIn < txTo.vin.size());
680 0 : const CTxIn& txin = txTo.vin[nIn];
681 0 : assert(txin.prevout.n < txFrom.vout.size());
682 0 : const CTxOut& txout = txFrom.vout[txin.prevout.n];
683 :
684 0 : return SignSignature(provider, txout.scriptPubKey, txTo, nIn, txout.nValue, nHashType, sig_data);
685 : }
686 :
687 : namespace {
688 : /** Dummy signature checker which accepts all signatures. */
689 : class DummySignatureChecker final : public BaseSignatureChecker
690 : {
691 : public:
692 2 : DummySignatureChecker() = default;
693 0 : bool CheckECDSASignature(const std::vector<unsigned char>& sig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const override { return sig.size() != 0; }
694 0 : bool CheckSchnorrSignature(Span<const unsigned char> sig, Span<const unsigned char> pubkey, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* serror) const override { return sig.size() != 0; }
695 0 : bool CheckLockTime(const CScriptNum& nLockTime) const override { return true; }
696 0 : bool CheckSequence(const CScriptNum& nSequence) const override { return true; }
697 : };
698 : }
699 :
700 2 : const BaseSignatureChecker& DUMMY_CHECKER = DummySignatureChecker();
701 :
702 : namespace {
703 : class DummySignatureCreator final : public BaseSignatureCreator {
704 : private:
705 : char m_r_len = 32;
706 : char m_s_len = 32;
707 : public:
708 4 : DummySignatureCreator(char r_len, char s_len) : m_r_len(r_len), m_s_len(s_len) {}
709 0 : const BaseSignatureChecker& Checker() const override { return DUMMY_CHECKER; }
710 0 : bool CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const override
711 : {
712 : // Create a dummy signature that is a valid DER-encoding
713 0 : vchSig.assign(m_r_len + m_s_len + 7, '\000');
714 0 : vchSig[0] = 0x30;
715 0 : vchSig[1] = m_r_len + m_s_len + 4;
716 0 : vchSig[2] = 0x02;
717 0 : vchSig[3] = m_r_len;
718 0 : vchSig[4] = 0x01;
719 0 : vchSig[4 + m_r_len] = 0x02;
720 0 : vchSig[5 + m_r_len] = m_s_len;
721 0 : vchSig[6 + m_r_len] = 0x01;
722 0 : vchSig[6 + m_r_len + m_s_len] = SIGHASH_ALL;
723 0 : return true;
724 : }
725 0 : bool CreateSchnorrSig(const SigningProvider& provider, std::vector<unsigned char>& sig, const XOnlyPubKey& pubkey, const uint256* leaf_hash, const uint256* tweak, SigVersion sigversion) const override
726 : {
727 0 : sig.assign(64, '\000');
728 0 : return true;
729 : }
730 : };
731 :
732 : }
733 :
734 2 : const BaseSignatureCreator& DUMMY_SIGNATURE_CREATOR = DummySignatureCreator(32, 32);
735 2 : const BaseSignatureCreator& DUMMY_MAXIMUM_SIGNATURE_CREATOR = DummySignatureCreator(33, 32);
736 :
737 0 : bool IsSegWitOutput(const SigningProvider& provider, const CScript& script)
738 : {
739 : int version;
740 0 : valtype program;
741 0 : if (script.IsWitnessProgram(version, program)) return true;
742 0 : if (script.IsPayToScriptHash()) {
743 0 : std::vector<valtype> solutions;
744 0 : auto whichtype = Solver(script, solutions);
745 0 : if (whichtype == TxoutType::SCRIPTHASH) {
746 0 : auto h160 = uint160(solutions[0]);
747 0 : CScript subscript;
748 0 : if (provider.GetCScript(CScriptID{h160}, subscript)) {
749 0 : if (subscript.IsWitnessProgram(version, program)) return true;
750 0 : }
751 0 : }
752 0 : }
753 0 : return false;
754 0 : }
755 :
756 0 : bool SignTransaction(CMutableTransaction& mtx, const SigningProvider* keystore, const std::map<COutPoint, Coin>& coins, int nHashType, std::map<int, bilingual_str>& input_errors)
757 : {
758 0 : bool fHashSingle = ((nHashType & ~SIGHASH_ANYONECANPAY) == SIGHASH_SINGLE);
759 :
760 : // Use CTransaction for the constant parts of the
761 : // transaction to avoid rehashing.
762 0 : const CTransaction txConst(mtx);
763 :
764 0 : PrecomputedTransactionData txdata;
765 0 : std::vector<CTxOut> spent_outputs;
766 0 : for (unsigned int i = 0; i < mtx.vin.size(); ++i) {
767 0 : CTxIn& txin = mtx.vin[i];
768 0 : auto coin = coins.find(txin.prevout);
769 0 : if (coin == coins.end() || coin->second.IsSpent()) {
770 0 : txdata.Init(txConst, /*spent_outputs=*/{}, /*force=*/true);
771 0 : break;
772 : } else {
773 0 : spent_outputs.emplace_back(coin->second.out.nValue, coin->second.out.scriptPubKey);
774 : }
775 0 : }
776 0 : if (spent_outputs.size() == mtx.vin.size()) {
777 0 : txdata.Init(txConst, std::move(spent_outputs), true);
778 0 : }
779 :
780 : // Sign what we can:
781 0 : for (unsigned int i = 0; i < mtx.vin.size(); ++i) {
782 0 : CTxIn& txin = mtx.vin[i];
783 0 : auto coin = coins.find(txin.prevout);
784 0 : if (coin == coins.end() || coin->second.IsSpent()) {
785 0 : input_errors[i] = _("Input not found or already spent");
786 0 : continue;
787 : }
788 0 : const CScript& prevPubKey = coin->second.out.scriptPubKey;
789 0 : const CAmount& amount = coin->second.out.nValue;
790 :
791 0 : SignatureData sigdata = DataFromTransaction(mtx, i, coin->second.out);
792 : // Only sign SIGHASH_SINGLE if there's a corresponding output:
793 0 : if (!fHashSingle || (i < mtx.vout.size())) {
794 0 : ProduceSignature(*keystore, MutableTransactionSignatureCreator(mtx, i, amount, &txdata, nHashType), prevPubKey, sigdata);
795 0 : }
796 :
797 0 : UpdateInput(txin, sigdata);
798 :
799 : // amount must be specified for valid segwit signature
800 0 : if (amount == MAX_MONEY && !txin.scriptWitness.IsNull()) {
801 0 : input_errors[i] = _("Missing amount");
802 0 : continue;
803 : }
804 :
805 0 : ScriptError serror = SCRIPT_ERR_OK;
806 0 : if (!VerifyScript(txin.scriptSig, prevPubKey, &txin.scriptWitness, STANDARD_SCRIPT_VERIFY_FLAGS, TransactionSignatureChecker(&txConst, i, amount, txdata, MissingDataBehavior::FAIL), &serror)) {
807 0 : if (serror == SCRIPT_ERR_INVALID_STACK_OPERATION) {
808 : // Unable to sign input and verification failed (possible attempt to partially sign).
809 0 : input_errors[i] = Untranslated("Unable to sign input, invalid stack size (possibly missing key)");
810 0 : } else if (serror == SCRIPT_ERR_SIG_NULLFAIL) {
811 : // Verification failed (possibly due to insufficient signatures).
812 0 : input_errors[i] = Untranslated("CHECK(MULTI)SIG failing with non-zero signature (possibly need more signatures)");
813 0 : } else {
814 0 : input_errors[i] = Untranslated(ScriptErrorString(serror));
815 : }
816 0 : } else {
817 : // If this input succeeds, make sure there is no error set for it
818 0 : input_errors.erase(i);
819 : }
820 0 : }
821 0 : return input_errors.empty();
822 0 : }
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