diff options
Diffstat (limited to 'src/script/interpreter.cpp')
| -rw-r--r-- | src/script/interpreter.cpp | 240 |
1 files changed, 227 insertions, 13 deletions
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp index fd4a5674cf..bc027e9f0c 100644 --- a/src/script/interpreter.cpp +++ b/src/script/interpreter.cpp @@ -229,7 +229,7 @@ bool static CheckMinimalPush(const valtype& data, opcodetype opcode) { return true; } -bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror) +bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror) { static const CScriptNum bnZero(0); static const CScriptNum bnOne(1); @@ -869,13 +869,15 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un CScript scriptCode(pbegincodehash, pend); // Drop the signature, since there's no way for a signature to sign itself - scriptCode.FindAndDelete(CScript(vchSig)); + if (sigversion == SIGVERSION_BASE) { + scriptCode.FindAndDelete(CScript(vchSig)); + } if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, serror)) { //serror is set return false; } - bool fSuccess = checker.CheckSig(vchSig, vchPubKey, scriptCode); + bool fSuccess = checker.CheckSig(vchSig, vchPubKey, scriptCode, sigversion); popstack(stack); popstack(stack); @@ -925,7 +927,9 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un for (int k = 0; k < nSigsCount; k++) { valtype& vchSig = stacktop(-isig-k); - scriptCode.FindAndDelete(CScript(vchSig)); + if (sigversion == SIGVERSION_BASE) { + scriptCode.FindAndDelete(CScript(vchSig)); + } } bool fSuccess = true; @@ -943,7 +947,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un } // Check signature - bool fOk = checker.CheckSig(vchSig, vchPubKey, scriptCode); + bool fOk = checker.CheckSig(vchSig, vchPubKey, scriptCode, sigversion); if (fOk) { isig++; @@ -1106,8 +1110,64 @@ public: } // anon namespace -uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType) +uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, const CAmount& amount, SigVersion sigversion) { + if (sigversion == SIGVERSION_WITNESS_V0) { + uint256 hashPrevouts; + uint256 hashSequence; + uint256 hashOutputs; + + if (!(nHashType & SIGHASH_ANYONECANPAY)) { + CHashWriter ss(SER_GETHASH, 0); + for (unsigned int n = 0; n < txTo.vin.size(); n++) { + ss << txTo.vin[n].prevout; + } + hashPrevouts = ss.GetHash(); // TODO: cache this value for all signatures in a transaction + } + + if (!(nHashType & SIGHASH_ANYONECANPAY) && (nHashType & 0x1f) != SIGHASH_SINGLE && (nHashType & 0x1f) != SIGHASH_NONE) { + CHashWriter ss(SER_GETHASH, 0); + for (unsigned int n = 0; n < txTo.vin.size(); n++) { + ss << txTo.vin[n].nSequence; + } + hashSequence = ss.GetHash(); // TODO: cache this value for all signatures in a transaction + } + + if ((nHashType & 0x1f) != SIGHASH_SINGLE && (nHashType & 0x1f) != SIGHASH_NONE) { + CHashWriter ss(SER_GETHASH, 0); + for (unsigned int n = 0; n < txTo.vout.size(); n++) { + ss << txTo.vout[n]; + } + hashOutputs = ss.GetHash(); // TODO: cache this value for all signatures in a transaction + } else if ((nHashType & 0x1f) == SIGHASH_SINGLE && nIn < txTo.vout.size()) { + CHashWriter ss(SER_GETHASH, 0); + ss << txTo.vout[nIn]; + hashOutputs = ss.GetHash(); + } + + CHashWriter ss(SER_GETHASH, 0); + // Version + ss << txTo.nVersion; + // Input prevouts/nSequence (none/all, depending on flags) + ss << hashPrevouts; + ss << hashSequence; + // The input being signed (replacing the scriptSig with scriptCode + amount) + // The prevout may already be contained in hashPrevout, and the nSequence + // may already be contain in hashSequence. + ss << txTo.vin[nIn].prevout; + ss << static_cast<const CScriptBase&>(scriptCode); + ss << amount; + ss << txTo.vin[nIn].nSequence; + // Outputs (none/one/all, depending on flags) + ss << hashOutputs; + // Locktime + ss << txTo.nLockTime; + // Sighash type + ss << nHashType; + + return ss.GetHash(); + } + static const uint256 one(uint256S("0000000000000000000000000000000000000000000000000000000000000001")); if (nIn >= txTo.vin.size()) { // nIn out of range @@ -1136,7 +1196,7 @@ bool TransactionSignatureChecker::VerifySignature(const std::vector<unsigned cha return pubkey.Verify(sighash, vchSig); } -bool TransactionSignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn, const vector<unsigned char>& vchPubKey, const CScript& scriptCode) const +bool TransactionSignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn, const vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const { CPubKey pubkey(vchPubKey); if (!pubkey.IsValid()) @@ -1149,7 +1209,7 @@ bool TransactionSignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn int nHashType = vchSig.back(); vchSig.pop_back(); - uint256 sighash = SignatureHash(scriptCode, *txTo, nIn, nHashType); + uint256 sighash = SignatureHash(scriptCode, *txTo, nIn, nHashType, amount, sigversion); if (!VerifySignature(vchSig, pubkey, sighash)) return false; @@ -1239,8 +1299,67 @@ bool TransactionSignatureChecker::CheckSequence(const CScriptNum& nSequence) con return true; } -bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror) +static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion, const std::vector<unsigned char>& program, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror) { + vector<vector<unsigned char> > stack; + CScript scriptPubKey; + + if (witversion == 0) { + if (program.size() == 32) { + // Version 0 segregated witness program: SHA256(CScript) inside the program, CScript + inputs in witness + if (witness.stack.size() == 0) { + return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_WITNESS_EMPTY); + } + scriptPubKey = CScript(witness.stack.back().begin(), witness.stack.back().end()); + stack = std::vector<std::vector<unsigned char> >(witness.stack.begin(), witness.stack.end() - 1); + uint256 hashScriptPubKey; + CSHA256().Write(&scriptPubKey[0], scriptPubKey.size()).Finalize(hashScriptPubKey.begin()); + if (memcmp(hashScriptPubKey.begin(), &program[0], 32)) { + return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_MISMATCH); + } + } else if (program.size() == 20) { + // Special case for pay-to-pubkeyhash; signature + pubkey in witness + if (witness.stack.size() != 2) { + return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_MISMATCH); // 2 items in witness + } + scriptPubKey << OP_DUP << OP_HASH160 << program << OP_EQUALVERIFY << OP_CHECKSIG; + stack = witness.stack; + } else { + return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_WRONG_LENGTH); + } + } else if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM) { + return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM); + } else { + // Higher version witness scripts return true for future softfork compatibility + return set_success(serror); + } + + // Disallow stack item size > MAX_SCRIPT_ELEMENT_SIZE in witness stack + for (unsigned int i = 0; i < stack.size(); i++) { + if (stack.at(i).size() > MAX_SCRIPT_ELEMENT_SIZE) + return set_error(serror, SCRIPT_ERR_PUSH_SIZE); + } + + if (!EvalScript(stack, scriptPubKey, flags, checker, SIGVERSION_WITNESS_V0, serror)) { + return false; + } + + // Scripts inside witness implicitly require cleanstack behaviour + if (stack.size() != 1) + return set_error(serror, SCRIPT_ERR_EVAL_FALSE); + if (!CastToBool(stack.back())) + return set_error(serror, SCRIPT_ERR_EVAL_FALSE); + return true; +} + +bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror) +{ + static const CScriptWitness emptyWitness; + if (witness == NULL) { + witness = &emptyWitness; + } + bool hadWitness = false; + set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR); if ((flags & SCRIPT_VERIFY_SIGPUSHONLY) != 0 && !scriptSig.IsPushOnly()) { @@ -1248,12 +1367,12 @@ bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigne } vector<vector<unsigned char> > stack, stackCopy; - if (!EvalScript(stack, scriptSig, flags, checker, serror)) + if (!EvalScript(stack, scriptSig, flags, checker, SIGVERSION_BASE, serror)) // serror is set return false; if (flags & SCRIPT_VERIFY_P2SH) stackCopy = stack; - if (!EvalScript(stack, scriptPubKey, flags, checker, serror)) + if (!EvalScript(stack, scriptPubKey, flags, checker, SIGVERSION_BASE, serror)) // serror is set return false; if (stack.empty()) @@ -1261,6 +1380,25 @@ bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigne if (CastToBool(stack.back()) == false) return set_error(serror, SCRIPT_ERR_EVAL_FALSE); + // Bare witness programs + int witnessversion; + std::vector<unsigned char> witnessprogram; + if (flags & SCRIPT_VERIFY_WITNESS) { + if (scriptPubKey.IsWitnessProgram(witnessversion, witnessprogram)) { + hadWitness = true; + if (scriptSig.size() != 0) { + // The scriptSig must be _exactly_ CScript(), otherwise we reintroduce malleability. + return set_error(serror, SCRIPT_ERR_WITNESS_MALLEATED); + } + if (!VerifyWitnessProgram(*witness, witnessversion, witnessprogram, flags, checker, serror)) { + return false; + } + // Bypass the cleanstack check at the end. The actual stack is obviously not clean + // for witness programs. + stack.resize(1); + } + } + // Additional validation for spend-to-script-hash transactions: if ((flags & SCRIPT_VERIFY_P2SH) && scriptPubKey.IsPayToScriptHash()) { @@ -1280,26 +1418,102 @@ bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigne CScript pubKey2(pubKeySerialized.begin(), pubKeySerialized.end()); popstack(stack); - if (!EvalScript(stack, pubKey2, flags, checker, serror)) + if (!EvalScript(stack, pubKey2, flags, checker, SIGVERSION_BASE, serror)) // serror is set return false; if (stack.empty()) return set_error(serror, SCRIPT_ERR_EVAL_FALSE); if (!CastToBool(stack.back())) return set_error(serror, SCRIPT_ERR_EVAL_FALSE); + + // P2SH witness program + if (flags & SCRIPT_VERIFY_WITNESS) { + if (pubKey2.IsWitnessProgram(witnessversion, witnessprogram)) { + hadWitness = true; + if (scriptSig != CScript() << std::vector<unsigned char>(pubKey2.begin(), pubKey2.end())) { + // The scriptSig must be _exactly_ a single push of the redeemScript. Otherwise we + // reintroduce malleability. + return set_error(serror, SCRIPT_ERR_WITNESS_MALLEATED_P2SH); + } + if (!VerifyWitnessProgram(*witness, witnessversion, witnessprogram, flags, checker, serror)) { + return false; + } + // Bypass the cleanstack check at the end. The actual stack is obviously not clean + // for witness programs. + stack.resize(1); + } + } } // The CLEANSTACK check is only performed after potential P2SH evaluation, // as the non-P2SH evaluation of a P2SH script will obviously not result in - // a clean stack (the P2SH inputs remain). + // a clean stack (the P2SH inputs remain). The same holds for witness evaluation. if ((flags & SCRIPT_VERIFY_CLEANSTACK) != 0) { // Disallow CLEANSTACK without P2SH, as otherwise a switch CLEANSTACK->P2SH+CLEANSTACK // would be possible, which is not a softfork (and P2SH should be one). assert((flags & SCRIPT_VERIFY_P2SH) != 0); + assert((flags & SCRIPT_VERIFY_WITNESS) != 0); if (stack.size() != 1) { return set_error(serror, SCRIPT_ERR_CLEANSTACK); } } + if (flags & SCRIPT_VERIFY_WITNESS) { + // We can't check for correct unexpected witness data if P2SH was off, so require + // that WITNESS implies P2SH. Otherwise, going from WITNESS->P2SH+WITNESS would be + // possible, which is not a softfork. + assert((flags & SCRIPT_VERIFY_P2SH) != 0); + if (!hadWitness && !witness->IsNull()) { + return set_error(serror, SCRIPT_ERR_WITNESS_UNEXPECTED); + } + } + return set_success(serror); } + +size_t static WitnessSigOps(int witversion, const std::vector<unsigned char>& witprogram, const CScriptWitness& witness, int flags) +{ + if (witversion == 0) { + if (witprogram.size() == 20) + return 1; + + if (witprogram.size() == 32 && witness.stack.size() > 0) { + CScript subscript(witness.stack.back().begin(), witness.stack.back().end()); + return subscript.GetSigOpCount(true); + } + } + + // Future flags may be implemented here. + return 0; +} + +size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags) +{ + static const CScriptWitness witnessEmpty; + + if ((flags & SCRIPT_VERIFY_WITNESS) == 0) { + return 0; + } + assert((flags & SCRIPT_VERIFY_P2SH) != 0); + + int witnessversion; + std::vector<unsigned char> witnessprogram; + if (scriptPubKey.IsWitnessProgram(witnessversion, witnessprogram)) { + return WitnessSigOps(witnessversion, witnessprogram, witness ? *witness : witnessEmpty, flags); + } + + if (scriptPubKey.IsPayToScriptHash() && scriptSig.IsPushOnly()) { + CScript::const_iterator pc = scriptSig.begin(); + vector<unsigned char> data; + while (pc < scriptSig.end()) { + opcodetype opcode; + scriptSig.GetOp(pc, opcode, data); + } + CScript subscript(data.begin(), data.end()); + if (subscript.IsWitnessProgram(witnessversion, witnessprogram)) { + return WitnessSigOps(witnessversion, witnessprogram, witness ? *witness : witnessEmpty, flags); + } + } + + return 0; +} |