git / moonbite-core / src/script/interpreter.cpp · raw
// Copyright (c) 2009-2010 Satoshi Nakamoto// Copyright (c) 2009-2020 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/interpreter.h>#include <crypto/ripemd160.h>#include <crypto/sha1.h>#include <crypto/sha256.h>#include <pubkey.h>#include <script/script.h>#include <uint256.h>typedef std::vector<unsigned char> valtype;namespace {inline bool set_success(ScriptError* ret){ if (ret) *ret = SCRIPT_ERR_OK; return true;}inline bool set_error(ScriptError* ret, const ScriptError serror){ if (ret) *ret = serror; return false;}} // namespacebool CastToBool(const valtype& vch){ for (unsigned int i = 0; i < vch.size(); i++) { if (vch[i] != 0) { // Can be negative zero if (i == vch.size()-1 && vch[i] == 0x80) return false; return true; } } return false;}/** * Script is a stack machine (like Forth) that evaluates a predicate * returning a bool indicating valid or not. There are no loops. */#define stacktop(i) (stack.at(stack.size()+(i)))#define altstacktop(i) (altstack.at(altstack.size()+(i)))static inline void popstack(std::vector<valtype>& stack){ if (stack.empty()) throw std::runtime_error("popstack(): stack empty"); stack.pop_back();}bool static IsCompressedOrUncompressedPubKey(const valtype &vchPubKey) { if (vchPubKey.size() < CPubKey::COMPRESSED_SIZE) { // Non-canonical public key: too short return false; } if (vchPubKey[0] == 0x04) { if (vchPubKey.size() != CPubKey::SIZE) { // Non-canonical public key: invalid length for uncompressed key return false; } } else if (vchPubKey[0] == 0x02 || vchPubKey[0] == 0x03) { if (vchPubKey.size() != CPubKey::COMPRESSED_SIZE) { // Non-canonical public key: invalid length for compressed key return false; } } else { // Non-canonical public key: neither compressed nor uncompressed return false; } return true;}bool static IsCompressedPubKey(const valtype &vchPubKey) { if (vchPubKey.size() != CPubKey::COMPRESSED_SIZE) { // Non-canonical public key: invalid length for compressed key return false; } if (vchPubKey[0] != 0x02 && vchPubKey[0] != 0x03) { // Non-canonical public key: invalid prefix for compressed key return false; } return true;}/** * A canonical signature exists of: <30> <total len> <02> <len R> <R> <02> <len S> <S> <hashtype> * Where R and S are not negative (their first byte has its highest bit not set), and not * excessively padded (do not start with a 0 byte, unless an otherwise negative number follows, * in which case a single 0 byte is necessary and even required). * * See https://bitcointalk.org/index.php?topic=8392.msg127623#msg127623 * * This function is consensus-critical since BIP66. */bool static IsValidSignatureEncoding(const std::vector<unsigned char> &sig) { // Format: 0x30 [total-length] 0x02 [R-length] [R] 0x02 [S-length] [S] [sighash] // * total-length: 1-byte length descriptor of everything that follows, // excluding the sighash byte. // * R-length: 1-byte length descriptor of the R value that follows. // * R: arbitrary-length big-endian encoded R value. It must use the shortest // possible encoding for a positive integer (which means no null bytes at // the start, except a single one when the next byte has its highest bit set). // * S-length: 1-byte length descriptor of the S value that follows. // * S: arbitrary-length big-endian encoded S value. The same rules apply. // * sighash: 1-byte value indicating what data is hashed (not part of the DER // signature) // Minimum and maximum size constraints. if (sig.size() < 9) return false; if (sig.size() > 73) return false; // A signature is of type 0x30 (compound). if (sig[0] != 0x30) return false; // Make sure the length covers the entire signature. if (sig[1] != sig.size() - 3) return false; // Extract the length of the R element. unsigned int lenR = sig[3]; // Make sure the length of the S element is still inside the signature. if (5 + lenR >= sig.size()) return false; // Extract the length of the S element. unsigned int lenS = sig[5 + lenR]; // Verify that the length of the signature matches the sum of the length // of the elements. if ((size_t)(lenR + lenS + 7) != sig.size()) return false; // Check whether the R element is an integer. if (sig[2] != 0x02) return false; // Zero-length integers are not allowed for R. if (lenR == 0) return false; // Negative numbers are not allowed for R. if (sig[4] & 0x80) return false; // Null bytes at the start of R are not allowed, unless R would // otherwise be interpreted as a negative number. if (lenR > 1 && (sig[4] == 0x00) && !(sig[5] & 0x80)) return false; // Check whether the S element is an integer. if (sig[lenR + 4] != 0x02) return false; // Zero-length integers are not allowed for S. if (lenS == 0) return false; // Negative numbers are not allowed for S. if (sig[lenR + 6] & 0x80) return false; // Null bytes at the start of S are not allowed, unless S would otherwise be // interpreted as a negative number. if (lenS > 1 && (sig[lenR + 6] == 0x00) && !(sig[lenR + 7] & 0x80)) return false; return true;}bool static IsLowDERSignature(const valtype &vchSig, ScriptError* serror) { if (!IsValidSignatureEncoding(vchSig)) { return set_error(serror, SCRIPT_ERR_SIG_DER); } // https://bitcoin.stackexchange.com/a/12556: // Also note that inside transaction signatures, an extra hashtype byte // follows the actual signature data. std::vector<unsigned char> vchSigCopy(vchSig.begin(), vchSig.begin() + vchSig.size() - 1); // If the S value is above the order of the curve divided by two, its // complement modulo the order could have been used instead, which is // one byte shorter when encoded correctly. if (!CPubKey::CheckLowS(vchSigCopy)) { return set_error(serror, SCRIPT_ERR_SIG_HIGH_S); } return true;}bool static IsDefinedHashtypeSignature(const valtype &vchSig) { if (vchSig.size() == 0) { return false; } unsigned char nHashType = vchSig[vchSig.size() - 1] & (~(SIGHASH_ANYONECANPAY)); if (nHashType < SIGHASH_ALL || nHashType > SIGHASH_SINGLE) return false; return true;}bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror) { // Empty signature. Not strictly DER encoded, but allowed to provide a // compact way to provide an invalid signature for use with CHECK(MULTI)SIG if (vchSig.size() == 0) { return true; } if ((flags & (SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC)) != 0 && !IsValidSignatureEncoding(vchSig)) { return set_error(serror, SCRIPT_ERR_SIG_DER); } else if ((flags & SCRIPT_VERIFY_LOW_S) != 0 && !IsLowDERSignature(vchSig, serror)) { // serror is set return false; } else if ((flags & SCRIPT_VERIFY_STRICTENC) != 0 && !IsDefinedHashtypeSignature(vchSig)) { return set_error(serror, SCRIPT_ERR_SIG_HASHTYPE); } return true;}bool static CheckPubKeyEncoding(const valtype &vchPubKey, unsigned int flags, const SigVersion &sigversion, ScriptError* serror) { if ((flags & SCRIPT_VERIFY_STRICTENC) != 0 && !IsCompressedOrUncompressedPubKey(vchPubKey)) { return set_error(serror, SCRIPT_ERR_PUBKEYTYPE); } // Only compressed keys are accepted in segwit if ((flags & SCRIPT_VERIFY_WITNESS_PUBKEYTYPE) != 0 && sigversion == SigVersion::WITNESS_V0 && !IsCompressedPubKey(vchPubKey)) { return set_error(serror, SCRIPT_ERR_WITNESS_PUBKEYTYPE); } return true;}bool static CheckMinimalPush(const valtype& data, opcodetype opcode) { // Excludes OP_1NEGATE, OP_1-16 since they are by definition minimal assert(0 <= opcode && opcode <= OP_PUSHDATA4); if (data.size() == 0) { // Should have used OP_0. return opcode == OP_0; } else if (data.size() == 1 && data[0] >= 1 && data[0] <= 16) { // Should have used OP_1 .. OP_16. return false; } else if (data.size() == 1 && data[0] == 0x81) { // Should have used OP_1NEGATE. return false; } else if (data.size() <= 75) { // Must have used a direct push (opcode indicating number of bytes pushed + those bytes). return opcode == data.size(); } else if (data.size() <= 255) { // Must have used OP_PUSHDATA. return opcode == OP_PUSHDATA1; } else if (data.size() <= 65535) { // Must have used OP_PUSHDATA2. return opcode == OP_PUSHDATA2; } return true;}int FindAndDelete(CScript& script, const CScript& b){ int nFound = 0; if (b.empty()) return nFound; CScript result; CScript::const_iterator pc = script.begin(), pc2 = script.begin(), end = script.end(); opcodetype opcode; do { result.insert(result.end(), pc2, pc); while (static_cast<size_t>(end - pc) >= b.size() && std::equal(b.begin(), b.end(), pc)) { pc = pc + b.size(); ++nFound; } pc2 = pc; } while (script.GetOp(pc, opcode)); if (nFound > 0) { result.insert(result.end(), pc2, end); script = std::move(result); } return nFound;}namespace {/** A data type to abstract out the condition stack during script execution. * * Conceptually it acts like a vector of booleans, one for each level of nested * IF/THEN/ELSE, indicating whether we're in the active or inactive branch of * each. * * The elements on the stack cannot be observed individually; we only need to * expose whether the stack is empty and whether or not any false values are * present at all. To implement OP_ELSE, a toggle_top modifier is added, which * flips the last value without returning it. * * This uses an optimized implementation that does not materialize the * actual stack. Instead, it just stores the size of the would-be stack, * and the position of the first false value in it. */class ConditionStack {private: //! A constant for m_first_false_pos to indicate there are no falses. static constexpr uint32_t NO_FALSE = std::numeric_limits<uint32_t>::max(); //! The size of the implied stack. uint32_t m_stack_size = 0; //! The position of the first false value on the implied stack, or NO_FALSE if all true. uint32_t m_first_false_pos = NO_FALSE;public: bool empty() { return m_stack_size == 0; } bool all_true() { return m_first_false_pos == NO_FALSE; } void push_back(bool f) { if (m_first_false_pos == NO_FALSE && !f) { // The stack consists of all true values, and a false is added. // The first false value will appear at the current size. m_first_false_pos = m_stack_size; } ++m_stack_size; } void pop_back() { assert(m_stack_size > 0); --m_stack_size; if (m_first_false_pos == m_stack_size) { // When popping off the first false value, everything becomes true. m_first_false_pos = NO_FALSE; } } void toggle_top() { assert(m_stack_size > 0); if (m_first_false_pos == NO_FALSE) { // The current stack is all true values; the first false will be the top. m_first_false_pos = m_stack_size - 1; } else if (m_first_false_pos == m_stack_size - 1) { // The top is the first false value; toggling it will make everything true. m_first_false_pos = NO_FALSE; } else { // There is a false value, but not on top. No action is needed as toggling // anything but the first false value is unobservable. } }};}static bool EvalChecksigPreTapscript(const valtype& vchSig, const valtype& vchPubKey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& fSuccess){ assert(sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0); // Subset of script starting at the most recent codeseparator CScript scriptCode(pbegincodehash, pend); // Drop the signature in pre-segwit scripts but not segwit scripts if (sigversion == SigVersion::BASE) { int found = FindAndDelete(scriptCode, CScript() << vchSig); if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE)) return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE); } if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) { //serror is set return false; } fSuccess = checker.CheckECDSASignature(vchSig, vchPubKey, scriptCode, sigversion); if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && vchSig.size()) return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL); return true;}static bool EvalChecksigTapscript(const valtype& sig, const valtype& pubkey, ScriptExecutionData& execdata, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& success){ assert(sigversion == SigVersion::TAPSCRIPT); /* * The following validation sequence is consensus critical. Please note how -- * upgradable public key versions precede other rules; * the script execution fails when using empty signature with invalid public key; * the script execution fails when using non-empty invalid signature. */ success = !sig.empty(); if (success) { // Implement the sigops/witnesssize ratio test. // Passing with an upgradable public key version is also counted. assert(execdata.m_validation_weight_left_init); execdata.m_validation_weight_left -= VALIDATION_WEIGHT_PER_SIGOP_PASSED; if (execdata.m_validation_weight_left < 0) { return set_error(serror, SCRIPT_ERR_TAPSCRIPT_VALIDATION_WEIGHT); } } if (pubkey.size() == 0) { return set_error(serror, SCRIPT_ERR_PUBKEYTYPE); } else if (pubkey.size() == 32) { if (success && !checker.CheckSchnorrSignature(sig, pubkey, sigversion, execdata, serror)) { return false; // serror is set } } else { /* * New public key version softforks should be defined before this `else` block. * Generally, the new code should not do anything but failing the script execution. To avoid * consensus bugs, it should not modify any existing values (including `success`). */ if ((flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE) != 0) { return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_PUBKEYTYPE); } } return true;}/** Helper for OP_CHECKSIG, OP_CHECKSIGVERIFY, and (in Tapscript) OP_CHECKSIGADD. * * A return value of false means the script fails entirely. When true is returned, the * success variable indicates whether the signature check itself succeeded. */static bool EvalChecksig(const valtype& sig, const valtype& pubkey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, ScriptExecutionData& execdata, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& success){ switch (sigversion) { case SigVersion::BASE: case SigVersion::WITNESS_V0: return EvalChecksigPreTapscript(sig, pubkey, pbegincodehash, pend, flags, checker, sigversion, serror, success); case SigVersion::TAPSCRIPT: return EvalChecksigTapscript(sig, pubkey, execdata, flags, checker, sigversion, serror, success); case SigVersion::TAPROOT: // Key path spending in Taproot has no script, so this is unreachable. break; } assert(false);}bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* serror){ static const CScriptNum bnZero(0); static const CScriptNum bnOne(1); // static const CScriptNum bnFalse(0); // static const CScriptNum bnTrue(1); static const valtype vchFalse(0); // static const valtype vchZero(0); static const valtype vchTrue(1, 1); // sigversion cannot be TAPROOT here, as it admits no script execution. assert(sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0 || sigversion == SigVersion::TAPSCRIPT); CScript::const_iterator pc = script.begin(); CScript::const_iterator pend = script.end(); CScript::const_iterator pbegincodehash = script.begin(); opcodetype opcode; valtype vchPushValue; ConditionStack vfExec; std::vector<valtype> altstack; set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR); if ((sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) && script.size() > MAX_SCRIPT_SIZE) { return set_error(serror, SCRIPT_ERR_SCRIPT_SIZE); } int nOpCount = 0; bool fRequireMinimal = (flags & SCRIPT_VERIFY_MINIMALDATA) != 0; uint32_t opcode_pos = 0; execdata.m_codeseparator_pos = 0xFFFFFFFFUL; execdata.m_codeseparator_pos_init = true; try { for (; pc < pend; ++opcode_pos) { bool fExec = vfExec.all_true(); // // Read instruction // if (!script.GetOp(pc, opcode, vchPushValue)) return set_error(serror, SCRIPT_ERR_BAD_OPCODE); if (vchPushValue.size() > MAX_SCRIPT_ELEMENT_SIZE) return set_error(serror, SCRIPT_ERR_PUSH_SIZE); if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) { // Note how OP_RESERVED does not count towards the opcode limit. if (opcode > OP_16 && ++nOpCount > MAX_OPS_PER_SCRIPT) { return set_error(serror, SCRIPT_ERR_OP_COUNT); } } if (opcode == OP_CAT || opcode == OP_SUBSTR || opcode == OP_LEFT || opcode == OP_RIGHT || opcode == OP_INVERT || opcode == OP_AND || opcode == OP_OR || opcode == OP_XOR || opcode == OP_2MUL || opcode == OP_2DIV || opcode == OP_MUL || opcode == OP_DIV || opcode == OP_MOD || opcode == OP_LSHIFT || opcode == OP_RSHIFT) return set_error(serror, SCRIPT_ERR_DISABLED_OPCODE); // Disabled opcodes (CVE-2010-5137). // With SCRIPT_VERIFY_CONST_SCRIPTCODE, OP_CODESEPARATOR in non-segwit script is rejected even in an unexecuted branch if (opcode == OP_CODESEPARATOR && sigversion == SigVersion::BASE && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE)) return set_error(serror, SCRIPT_ERR_OP_CODESEPARATOR); if (fExec && 0 <= opcode && opcode <= OP_PUSHDATA4) { if (fRequireMinimal && !CheckMinimalPush(vchPushValue, opcode)) { return set_error(serror, SCRIPT_ERR_MINIMALDATA); } stack.push_back(vchPushValue); } else if (fExec || (OP_IF <= opcode && opcode <= OP_ENDIF)) switch (opcode) { // // Push value // case OP_1NEGATE: case OP_1: case OP_2: case OP_3: case OP_4: case OP_5: case OP_6: case OP_7: case OP_8: case OP_9: case OP_10: case OP_11: case OP_12: case OP_13: case OP_14: case OP_15: case OP_16: { // ( -- value) CScriptNum bn((int)opcode - (int)(OP_1 - 1)); stack.push_back(bn.getvch()); // The result of these opcodes should always be the minimal way to push the data // they push, so no need for a CheckMinimalPush here. } break; // // Control // case OP_NOP: break; case OP_CHECKLOCKTIMEVERIFY: { if (!(flags & SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY)) { // not enabled; treat as a NOP2 break; } if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); // Note that elsewhere numeric opcodes are limited to // operands in the range -2**31+1 to 2**31-1, however it is // legal for opcodes to produce results exceeding that // range. This limitation is implemented by CScriptNum's // default 4-byte limit. // // If we kept to that limit we'd have a year 2038 problem, // even though the nLockTime field in transactions // themselves is uint32 which only becomes meaningless // after the year 2106. // // Thus as a special case we tell CScriptNum to accept up // to 5-byte bignums, which are good until 2**39-1, well // beyond the 2**32-1 limit of the nLockTime field itself. const CScriptNum nLockTime(stacktop(-1), fRequireMinimal, 5); // In the rare event that the argument may be < 0 due to // some arithmetic being done first, you can always use // 0 MAX CHECKLOCKTIMEVERIFY. if (nLockTime < 0) return set_error(serror, SCRIPT_ERR_NEGATIVE_LOCKTIME); // Actually compare the specified lock time with the transaction. if (!checker.CheckLockTime(nLockTime)) return set_error(serror, SCRIPT_ERR_UNSATISFIED_LOCKTIME); break; } case OP_CHECKSEQUENCEVERIFY: { if (!(flags & SCRIPT_VERIFY_CHECKSEQUENCEVERIFY)) { // not enabled; treat as a NOP3 break; } if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); // nSequence, like nLockTime, is a 32-bit unsigned integer // field. See the comment in CHECKLOCKTIMEVERIFY regarding // 5-byte numeric operands. const CScriptNum nSequence(stacktop(-1), fRequireMinimal, 5); // In the rare event that the argument may be < 0 due to // some arithmetic being done first, you can always use // 0 MAX CHECKSEQUENCEVERIFY. if (nSequence < 0) return set_error(serror, SCRIPT_ERR_NEGATIVE_LOCKTIME); // To provide for future soft-fork extensibility, if the // operand has the disabled lock-time flag set, // CHECKSEQUENCEVERIFY behaves as a NOP. if ((nSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) != 0) break; // Compare the specified sequence number with the input. if (!checker.CheckSequence(nSequence)) return set_error(serror, SCRIPT_ERR_UNSATISFIED_LOCKTIME); break; } case OP_NOP1: case OP_NOP4: case OP_NOP5: case OP_NOP6: case OP_NOP7: case OP_NOP8: case OP_NOP9: case OP_NOP10: { if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS); } break; case OP_IF: case OP_NOTIF: { // <expression> if [statements] [else [statements]] endif bool fValue = false; if (fExec) { if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_UNBALANCED_CONDITIONAL); valtype& vch = stacktop(-1); // Tapscript requires minimal IF/NOTIF inputs as a consensus rule. if (sigversion == SigVersion::TAPSCRIPT) { // The input argument to the OP_IF and OP_NOTIF opcodes must be either // exactly 0 (the empty vector) or exactly 1 (the one-byte vector with value 1). if (vch.size() > 1 || (vch.size() == 1 && vch[0] != 1)) { return set_error(serror, SCRIPT_ERR_TAPSCRIPT_MINIMALIF); } } // Under witness v0 rules it is only a policy rule, enabled through SCRIPT_VERIFY_MINIMALIF. if (sigversion == SigVersion::WITNESS_V0 && (flags & SCRIPT_VERIFY_MINIMALIF)) { if (vch.size() > 1) return set_error(serror, SCRIPT_ERR_MINIMALIF); if (vch.size() == 1 && vch[0] != 1) return set_error(serror, SCRIPT_ERR_MINIMALIF); } fValue = CastToBool(vch); if (opcode == OP_NOTIF) fValue = !fValue; popstack(stack); } vfExec.push_back(fValue); } break; case OP_ELSE: { if (vfExec.empty()) return set_error(serror, SCRIPT_ERR_UNBALANCED_CONDITIONAL); vfExec.toggle_top(); } break; case OP_ENDIF: { if (vfExec.empty()) return set_error(serror, SCRIPT_ERR_UNBALANCED_CONDITIONAL); vfExec.pop_back(); } break; case OP_VERIFY: { // (true -- ) or // (false -- false) and return if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); bool fValue = CastToBool(stacktop(-1)); if (fValue) popstack(stack); else return set_error(serror, SCRIPT_ERR_VERIFY); } break; case OP_RETURN: { return set_error(serror, SCRIPT_ERR_OP_RETURN); } break; // // Stack ops // case OP_TOALTSTACK: { if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); altstack.push_back(stacktop(-1)); popstack(stack); } break; case OP_FROMALTSTACK: { if (altstack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_ALTSTACK_OPERATION); stack.push_back(altstacktop(-1)); popstack(altstack); } break; case OP_2DROP: { // (x1 x2 -- ) if (stack.size() < 2) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); popstack(stack); popstack(stack); } break; case OP_2DUP: { // (x1 x2 -- x1 x2 x1 x2) if (stack.size() < 2) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch1 = stacktop(-2); valtype vch2 = stacktop(-1); stack.push_back(vch1); stack.push_back(vch2); } break; case OP_3DUP: { // (x1 x2 x3 -- x1 x2 x3 x1 x2 x3) if (stack.size() < 3) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch1 = stacktop(-3); valtype vch2 = stacktop(-2); valtype vch3 = stacktop(-1); stack.push_back(vch1); stack.push_back(vch2); stack.push_back(vch3); } break; case OP_2OVER: { // (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2) if (stack.size() < 4) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch1 = stacktop(-4); valtype vch2 = stacktop(-3); stack.push_back(vch1); stack.push_back(vch2); } break; case OP_2ROT: { // (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2) if (stack.size() < 6) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch1 = stacktop(-6); valtype vch2 = stacktop(-5); stack.erase(stack.end()-6, stack.end()-4); stack.push_back(vch1); stack.push_back(vch2); } break; case OP_2SWAP: { // (x1 x2 x3 x4 -- x3 x4 x1 x2) if (stack.size() < 4) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); swap(stacktop(-4), stacktop(-2)); swap(stacktop(-3), stacktop(-1)); } break; case OP_IFDUP: { // (x - 0 | x x) if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch = stacktop(-1); if (CastToBool(vch)) stack.push_back(vch); } break; case OP_DEPTH: { // -- stacksize CScriptNum bn(stack.size()); stack.push_back(bn.getvch()); } break; case OP_DROP: { // (x -- ) if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); popstack(stack); } break; case OP_DUP: { // (x -- x x) if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch = stacktop(-1); stack.push_back(vch); } break; case OP_NIP: { // (x1 x2 -- x2) if (stack.size() < 2) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); stack.erase(stack.end() - 2); } break; case OP_OVER: { // (x1 x2 -- x1 x2 x1) if (stack.size() < 2) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch = stacktop(-2); stack.push_back(vch); } break; case OP_PICK: case OP_ROLL: { // (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn) // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn) if (stack.size() < 2) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); int n = CScriptNum(stacktop(-1), fRequireMinimal).getint(); popstack(stack); if (n < 0 || n >= (int)stack.size()) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch = stacktop(-n-1); if (opcode == OP_ROLL) stack.erase(stack.end()-n-1); stack.push_back(vch); } break; case OP_ROT: { // (x1 x2 x3 -- x2 x3 x1) // x2 x1 x3 after first swap // x2 x3 x1 after second swap if (stack.size() < 3) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); swap(stacktop(-3), stacktop(-2)); swap(stacktop(-2), stacktop(-1)); } break; case OP_SWAP: { // (x1 x2 -- x2 x1) if (stack.size() < 2) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); swap(stacktop(-2), stacktop(-1)); } break; case OP_TUCK: { // (x1 x2 -- x2 x1 x2) if (stack.size() < 2) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch = stacktop(-1); stack.insert(stack.end()-2, vch); } break; case OP_SIZE: { // (in -- in size) if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); CScriptNum bn(stacktop(-1).size()); stack.push_back(bn.getvch()); } break; // // Bitwise logic // case OP_EQUAL: case OP_EQUALVERIFY: //case OP_NOTEQUAL: // use OP_NUMNOTEQUAL { // (x1 x2 - bool) if (stack.size() < 2) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype& vch1 = stacktop(-2); valtype& vch2 = stacktop(-1); bool fEqual = (vch1 == vch2); // OP_NOTEQUAL is disabled because it would be too easy to say // something like n != 1 and have some wiseguy pass in 1 with extra // zero bytes after it (numerically, 0x01 == 0x0001 == 0x000001) //if (opcode == OP_NOTEQUAL) // fEqual = !fEqual; popstack(stack); popstack(stack); stack.push_back(fEqual ? vchTrue : vchFalse); if (opcode == OP_EQUALVERIFY) { if (fEqual) popstack(stack); else return set_error(serror, SCRIPT_ERR_EQUALVERIFY); } } break; // // Numeric // case OP_1ADD: case OP_1SUB: case OP_NEGATE: case OP_ABS: case OP_NOT: case OP_0NOTEQUAL: { // (in -- out) if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); CScriptNum bn(stacktop(-1), fRequireMinimal); switch (opcode) { case OP_1ADD: bn += bnOne; break; case OP_1SUB: bn -= bnOne; break; case OP_NEGATE: bn = -bn; break; case OP_ABS: if (bn < bnZero) bn = -bn; break; case OP_NOT: bn = (bn == bnZero); break; case OP_0NOTEQUAL: bn = (bn != bnZero); break; default: assert(!"invalid opcode"); break; } popstack(stack); stack.push_back(bn.getvch()); } break; case OP_ADD: case OP_SUB: case OP_BOOLAND: case OP_BOOLOR: case OP_NUMEQUAL: case OP_NUMEQUALVERIFY: case OP_NUMNOTEQUAL: case OP_LESSTHAN: case OP_GREATERTHAN: case OP_LESSTHANOREQUAL: case OP_GREATERTHANOREQUAL: case OP_MIN: case OP_MAX: { // (x1 x2 -- out) if (stack.size() < 2) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); CScriptNum bn1(stacktop(-2), fRequireMinimal); CScriptNum bn2(stacktop(-1), fRequireMinimal); CScriptNum bn(0); switch (opcode) { case OP_ADD: bn = bn1 + bn2; break; case OP_SUB: bn = bn1 - bn2; break; case OP_BOOLAND: bn = (bn1 != bnZero && bn2 != bnZero); break; case OP_BOOLOR: bn = (bn1 != bnZero || bn2 != bnZero); break; case OP_NUMEQUAL: bn = (bn1 == bn2); break; case OP_NUMEQUALVERIFY: bn = (bn1 == bn2); break; case OP_NUMNOTEQUAL: bn = (bn1 != bn2); break; case OP_LESSTHAN: bn = (bn1 < bn2); break; case OP_GREATERTHAN: bn = (bn1 > bn2); break; case OP_LESSTHANOREQUAL: bn = (bn1 <= bn2); break; case OP_GREATERTHANOREQUAL: bn = (bn1 >= bn2); break; case OP_MIN: bn = (bn1 < bn2 ? bn1 : bn2); break; case OP_MAX: bn = (bn1 > bn2 ? bn1 : bn2); break; default: assert(!"invalid opcode"); break; } popstack(stack); popstack(stack); stack.push_back(bn.getvch()); if (opcode == OP_NUMEQUALVERIFY) { if (CastToBool(stacktop(-1))) popstack(stack); else return set_error(serror, SCRIPT_ERR_NUMEQUALVERIFY); } } break; case OP_WITHIN: { // (x min max -- out) if (stack.size() < 3) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); CScriptNum bn1(stacktop(-3), fRequireMinimal); CScriptNum bn2(stacktop(-2), fRequireMinimal); CScriptNum bn3(stacktop(-1), fRequireMinimal); bool fValue = (bn2 <= bn1 && bn1 < bn3); popstack(stack); popstack(stack); popstack(stack); stack.push_back(fValue ? vchTrue : vchFalse); } break; // // Crypto // case OP_RIPEMD160: case OP_SHA1: case OP_SHA256: case OP_HASH160: case OP_HASH256: { // (in -- hash) if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype& vch = stacktop(-1); valtype vchHash((opcode == OP_RIPEMD160 || opcode == OP_SHA1 || opcode == OP_HASH160) ? 20 : 32); if (opcode == OP_RIPEMD160) CRIPEMD160().Write(vch.data(), vch.size()).Finalize(vchHash.data()); else if (opcode == OP_SHA1) CSHA1().Write(vch.data(), vch.size()).Finalize(vchHash.data()); else if (opcode == OP_SHA256) CSHA256().Write(vch.data(), vch.size()).Finalize(vchHash.data()); else if (opcode == OP_HASH160) CHash160().Write(vch).Finalize(vchHash); else if (opcode == OP_HASH256) CHash256().Write(vch).Finalize(vchHash); popstack(stack); stack.push_back(vchHash); } break; case OP_CODESEPARATOR: { // If SCRIPT_VERIFY_CONST_SCRIPTCODE flag is set, use of OP_CODESEPARATOR is rejected in pre-segwit // script, even in an unexecuted branch (this is checked above the opcode case statement). // Hash starts after the code separator pbegincodehash = pc; execdata.m_codeseparator_pos = opcode_pos; } break; case OP_CHECKSIG: case OP_CHECKSIGVERIFY: { // (sig pubkey -- bool) if (stack.size() < 2) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype& vchSig = stacktop(-2); valtype& vchPubKey = stacktop(-1); bool fSuccess = true; if (!EvalChecksig(vchSig, vchPubKey, pbegincodehash, pend, execdata, flags, checker, sigversion, serror, fSuccess)) return false; popstack(stack); popstack(stack); stack.push_back(fSuccess ? vchTrue : vchFalse); if (opcode == OP_CHECKSIGVERIFY) { if (fSuccess) popstack(stack); else return set_error(serror, SCRIPT_ERR_CHECKSIGVERIFY); } } break; case OP_CHECKSIGADD: { // OP_CHECKSIGADD is only available in Tapscript if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE); // (sig num pubkey -- num) if (stack.size() < 3) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); const valtype& sig = stacktop(-3); const CScriptNum num(stacktop(-2), fRequireMinimal); const valtype& pubkey = stacktop(-1); bool success = true; if (!EvalChecksig(sig, pubkey, pbegincodehash, pend, execdata, flags, checker, sigversion, serror, success)) return false; popstack(stack); popstack(stack); popstack(stack); stack.push_back((num + (success ? 1 : 0)).getvch()); } break; case OP_CHECKMULTISIG: case OP_CHECKMULTISIGVERIFY: { if (sigversion == SigVersion::TAPSCRIPT) return set_error(serror, SCRIPT_ERR_TAPSCRIPT_CHECKMULTISIG); // ([sig ...] num_of_signatures [pubkey ...] num_of_pubkeys -- bool) int i = 1; if ((int)stack.size() < i) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); int nKeysCount = CScriptNum(stacktop(-i), fRequireMinimal).getint(); if (nKeysCount < 0 || nKeysCount > MAX_PUBKEYS_PER_MULTISIG) return set_error(serror, SCRIPT_ERR_PUBKEY_COUNT); nOpCount += nKeysCount; if (nOpCount > MAX_OPS_PER_SCRIPT) return set_error(serror, SCRIPT_ERR_OP_COUNT); int ikey = ++i; // ikey2 is the position of last non-signature item in the stack. Top stack item = 1. // With SCRIPT_VERIFY_NULLFAIL, this is used for cleanup if operation fails. int ikey2 = nKeysCount + 2; i += nKeysCount; if ((int)stack.size() < i) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); int nSigsCount = CScriptNum(stacktop(-i), fRequireMinimal).getint(); if (nSigsCount < 0 || nSigsCount > nKeysCount) return set_error(serror, SCRIPT_ERR_SIG_COUNT); int isig = ++i; i += nSigsCount; if ((int)stack.size() < i) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); // Subset of script starting at the most recent codeseparator CScript scriptCode(pbegincodehash, pend); // Drop the signature in pre-segwit scripts but not segwit scripts for (int k = 0; k < nSigsCount; k++) { valtype& vchSig = stacktop(-isig-k); if (sigversion == SigVersion::BASE) { int found = FindAndDelete(scriptCode, CScript() << vchSig); if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE)) return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE); } } bool fSuccess = true; while (fSuccess && nSigsCount > 0) { valtype& vchSig = stacktop(-isig); valtype& vchPubKey = stacktop(-ikey); // Note how this makes the exact order of pubkey/signature evaluation // distinguishable by CHECKMULTISIG NOT if the STRICTENC flag is set. // See the script_(in)valid tests for details. if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) { // serror is set return false; } // Check signature bool fOk = checker.CheckECDSASignature(vchSig, vchPubKey, scriptCode, sigversion); if (fOk) { isig++; nSigsCount--; } ikey++; nKeysCount--; // If there are more signatures left than keys left, // then too many signatures have failed. Exit early, // without checking any further signatures. if (nSigsCount > nKeysCount) fSuccess = false; } // Clean up stack of actual arguments while (i-- > 1) { // If the operation failed, we require that all signatures must be empty vector if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && !ikey2 && stacktop(-1).size()) return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL); if (ikey2 > 0) ikey2--; popstack(stack); } // A bug causes CHECKMULTISIG to consume one extra argument // whose contents were not checked in any way. // // Unfortunately this is a potential source of mutability, // so optionally verify it is exactly equal to zero prior // to removing it from the stack. if (stack.size() < 1) return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); if ((flags & SCRIPT_VERIFY_NULLDUMMY) && stacktop(-1).size()) return set_error(serror, SCRIPT_ERR_SIG_NULLDUMMY); popstack(stack); stack.push_back(fSuccess ? vchTrue : vchFalse); if (opcode == OP_CHECKMULTISIGVERIFY) { if (fSuccess) popstack(stack); else return set_error(serror, SCRIPT_ERR_CHECKMULTISIGVERIFY); } } break; default: return set_error(serror, SCRIPT_ERR_BAD_OPCODE); } // Size limits if (stack.size() + altstack.size() > MAX_STACK_SIZE) return set_error(serror, SCRIPT_ERR_STACK_SIZE); } } catch (...) { return set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR); } if (!vfExec.empty()) return set_error(serror, SCRIPT_ERR_UNBALANCED_CONDITIONAL); return set_success(serror);}bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror){ ScriptExecutionData execdata; return EvalScript(stack, script, flags, checker, sigversion, execdata, serror);}namespace {/** * Wrapper that serializes like CTransaction, but with the modifications * required for the signature hash done in-place */template <class T>class CTransactionSignatureSerializer{private: const T& txTo; //!< reference to the spending transaction (the one being serialized) const CScript& scriptCode; //!< output script being consumed const unsigned int nIn; //!< input index of txTo being signed const bool fAnyoneCanPay; //!< whether the hashtype has the SIGHASH_ANYONECANPAY flag set const bool fHashSingle; //!< whether the hashtype is SIGHASH_SINGLE const bool fHashNone; //!< whether the hashtype is SIGHASH_NONEpublic: CTransactionSignatureSerializer(const T& txToIn, const CScript& scriptCodeIn, unsigned int nInIn, int nHashTypeIn) : txTo(txToIn), scriptCode(scriptCodeIn), nIn(nInIn), fAnyoneCanPay(!!(nHashTypeIn & SIGHASH_ANYONECANPAY)), fHashSingle((nHashTypeIn & 0x1f) == SIGHASH_SINGLE), fHashNone((nHashTypeIn & 0x1f) == SIGHASH_NONE) {} /** Serialize the passed scriptCode, skipping OP_CODESEPARATORs */ template<typename S> void SerializeScriptCode(S &s) const { CScript::const_iterator it = scriptCode.begin(); CScript::const_iterator itBegin = it; opcodetype opcode; unsigned int nCodeSeparators = 0; while (scriptCode.GetOp(it, opcode)) { if (opcode == OP_CODESEPARATOR) nCodeSeparators++; } ::WriteCompactSize(s, scriptCode.size() - nCodeSeparators); it = itBegin; while (scriptCode.GetOp(it, opcode)) { if (opcode == OP_CODESEPARATOR) { s.write((char*)&itBegin[0], it-itBegin-1); itBegin = it; } } if (itBegin != scriptCode.end()) s.write((char*)&itBegin[0], it-itBegin); } /** Serialize an input of txTo */ template<typename S> void SerializeInput(S &s, unsigned int nInput) const { // In case of SIGHASH_ANYONECANPAY, only the input being signed is serialized if (fAnyoneCanPay) nInput = nIn; // Serialize the prevout ::Serialize(s, txTo.vin[nInput].prevout); // Serialize the script if (nInput != nIn) // Blank out other inputs' signatures ::Serialize(s, CScript()); else SerializeScriptCode(s); // Serialize the nSequence if (nInput != nIn && (fHashSingle || fHashNone)) // let the others update at will ::Serialize(s, (int)0); else ::Serialize(s, txTo.vin[nInput].nSequence); } /** Serialize an output of txTo */ template<typename S> void SerializeOutput(S &s, unsigned int nOutput) const { if (fHashSingle && nOutput != nIn) // Do not lock-in the txout payee at other indices as txin ::Serialize(s, CTxOut()); else ::Serialize(s, txTo.vout[nOutput]); } /** Serialize txTo */ template<typename S> void Serialize(S &s) const { // Serialize nVersion ::Serialize(s, txTo.nVersion); // Serialize vin unsigned int nInputs = fAnyoneCanPay ? 1 : txTo.vin.size(); ::WriteCompactSize(s, nInputs); for (unsigned int nInput = 0; nInput < nInputs; nInput++) SerializeInput(s, nInput); // Serialize vout unsigned int nOutputs = fHashNone ? 0 : (fHashSingle ? nIn+1 : txTo.vout.size()); ::WriteCompactSize(s, nOutputs); for (unsigned int nOutput = 0; nOutput < nOutputs; nOutput++) SerializeOutput(s, nOutput); // Serialize nLockTime ::Serialize(s, txTo.nLockTime); }};/** Compute the (single) SHA256 of the concatenation of all prevouts of a tx. */template <class T>uint256 GetPrevoutsSHA256(const T& txTo){ CHashWriter ss(SER_GETHASH, 0); for (const auto& txin : txTo.vin) { ss << txin.prevout; } return ss.GetSHA256();}/** Compute the (single) SHA256 of the concatenation of all nSequences of a tx. */template <class T>uint256 GetSequencesSHA256(const T& txTo){ CHashWriter ss(SER_GETHASH, 0); for (const auto& txin : txTo.vin) { ss << txin.nSequence; } return ss.GetSHA256();}/** Compute the (single) SHA256 of the concatenation of all txouts of a tx. */template <class T>uint256 GetOutputsSHA256(const T& txTo){ CHashWriter ss(SER_GETHASH, 0); for (const auto& txout : txTo.vout) { ss << txout; } return ss.GetSHA256();}/** Compute the (single) SHA256 of the concatenation of all amounts spent by a tx. */uint256 GetSpentAmountsSHA256(const std::vector<CTxOut>& outputs_spent){ CHashWriter ss(SER_GETHASH, 0); for (const auto& txout : outputs_spent) { ss << txout.nValue; } return ss.GetSHA256();}/** Compute the (single) SHA256 of the concatenation of all scriptPubKeys spent by a tx. */uint256 GetSpentScriptsSHA256(const std::vector<CTxOut>& outputs_spent){ CHashWriter ss(SER_GETHASH, 0); for (const auto& txout : outputs_spent) { ss << txout.scriptPubKey; } return ss.GetSHA256();}} // namespacetemplate <class T>void PrecomputedTransactionData::Init(const T& txTo, std::vector<CTxOut>&& spent_outputs){ assert(!m_spent_outputs_ready); m_spent_outputs = std::move(spent_outputs); if (!m_spent_outputs.empty()) { assert(m_spent_outputs.size() == txTo.vin.size()); m_spent_outputs_ready = true; } // Determine which precomputation-impacting features this transaction uses. bool uses_bip143_segwit = false; bool uses_bip341_taproot = false; for (size_t inpos = 0; inpos < txTo.vin.size(); ++inpos) { if (!txTo.vin[inpos].scriptWitness.IsNull()) { if (m_spent_outputs_ready && m_spent_outputs[inpos].scriptPubKey.size() == 2 + WITNESS_V1_TAPROOT_SIZE && m_spent_outputs[inpos].scriptPubKey[0] == OP_1) { // Treat every witness-bearing spend with 34-byte scriptPubKey that starts with OP_1 as a Taproot // spend. This only works if spent_outputs was provided as well, but if it wasn't, actual validation // will fail anyway. Note that this branch may trigger for scriptPubKeys that aren't actually segwit // but in that case validation will fail as SCRIPT_ERR_WITNESS_UNEXPECTED anyway. uses_bip341_taproot = true; } else { // Treat every spend that's not known to native witness v1 as a Witness v0 spend. This branch may // also be taken for unknown witness versions, but it is harmless, and being precise would require // P2SH evaluation to find the redeemScript. uses_bip143_segwit = true; } } if (uses_bip341_taproot && uses_bip143_segwit) break; // No need to scan further if we already need all. } if (uses_bip143_segwit || uses_bip341_taproot) { // Computations shared between both sighash schemes. m_prevouts_single_hash = GetPrevoutsSHA256(txTo); m_sequences_single_hash = GetSequencesSHA256(txTo); m_outputs_single_hash = GetOutputsSHA256(txTo); } if (uses_bip143_segwit) { hashPrevouts = SHA256Uint256(m_prevouts_single_hash); hashSequence = SHA256Uint256(m_sequences_single_hash); hashOutputs = SHA256Uint256(m_outputs_single_hash); m_bip143_segwit_ready = true; } if (uses_bip341_taproot) { m_spent_amounts_single_hash = GetSpentAmountsSHA256(m_spent_outputs); m_spent_scripts_single_hash = GetSpentScriptsSHA256(m_spent_outputs); m_bip341_taproot_ready = true; }}template <class T>PrecomputedTransactionData::PrecomputedTransactionData(const T& txTo){ Init(txTo, {});}// explicit instantiationtemplate void PrecomputedTransactionData::Init(const CTransaction& txTo, std::vector<CTxOut>&& spent_outputs);template void PrecomputedTransactionData::Init(const CMutableTransaction& txTo, std::vector<CTxOut>&& spent_outputs);template PrecomputedTransactionData::PrecomputedTransactionData(const CTransaction& txTo);template PrecomputedTransactionData::PrecomputedTransactionData(const CMutableTransaction& txTo);static const CHashWriter HASHER_TAPSIGHASH = TaggedHash("TapSighash");static const CHashWriter HASHER_TAPLEAF = TaggedHash("TapLeaf");static const CHashWriter HASHER_TAPBRANCH = TaggedHash("TapBranch");static const CHashWriter HASHER_TAPTWEAK = TaggedHash("TapTweak");template<typename T>bool SignatureHashSchnorr(uint256& hash_out, const ScriptExecutionData& execdata, const T& tx_to, uint32_t in_pos, uint8_t hash_type, SigVersion sigversion, const PrecomputedTransactionData& cache){ uint8_t ext_flag, key_version; switch (sigversion) { case SigVersion::TAPROOT: ext_flag = 0; // key_version is not used and left uninitialized. break; case SigVersion::TAPSCRIPT: ext_flag = 1; // key_version must be 0 for now, representing the current version of // 32-byte public keys in the tapscript signature opcode execution. // An upgradable public key version (with a size not 32-byte) may // request a different key_version with a new sigversion. key_version = 0; break; default: assert(false); } assert(in_pos < tx_to.vin.size()); assert(cache.m_bip341_taproot_ready && cache.m_spent_outputs_ready); CHashWriter ss = HASHER_TAPSIGHASH; // Epoch static constexpr uint8_t EPOCH = 0; ss << EPOCH; // Hash type const uint8_t output_type = (hash_type == SIGHASH_DEFAULT) ? SIGHASH_ALL : (hash_type & SIGHASH_OUTPUT_MASK); // Default (no sighash byte) is equivalent to SIGHASH_ALL const uint8_t input_type = hash_type & SIGHASH_INPUT_MASK; if (!(hash_type <= 0x03 || (hash_type >= 0x81 && hash_type <= 0x83))) return false; ss << hash_type; // Transaction level data ss << tx_to.nVersion; ss << tx_to.nLockTime; if (input_type != SIGHASH_ANYONECANPAY) { ss << cache.m_prevouts_single_hash; ss << cache.m_spent_amounts_single_hash; ss << cache.m_spent_scripts_single_hash; ss << cache.m_sequences_single_hash; } if (output_type == SIGHASH_ALL) { ss << cache.m_outputs_single_hash; } // Data about the input/prevout being spent assert(execdata.m_annex_init); const bool have_annex = execdata.m_annex_present; const uint8_t spend_type = (ext_flag << 1) + (have_annex ? 1 : 0); // The low bit indicates whether an annex is present. ss << spend_type; if (input_type == SIGHASH_ANYONECANPAY) { ss << tx_to.vin[in_pos].prevout; ss << cache.m_spent_outputs[in_pos]; ss << tx_to.vin[in_pos].nSequence; } else { ss << in_pos; } if (have_annex) { ss << execdata.m_annex_hash; } // Data about the output (if only one). if (output_type == SIGHASH_SINGLE) { if (in_pos >= tx_to.vout.size()) return false; CHashWriter sha_single_output(SER_GETHASH, 0); sha_single_output << tx_to.vout[in_pos]; ss << sha_single_output.GetSHA256(); } // Additional data for BIP 342 signatures if (sigversion == SigVersion::TAPSCRIPT) { assert(execdata.m_tapleaf_hash_init); ss << execdata.m_tapleaf_hash; ss << key_version; assert(execdata.m_codeseparator_pos_init); ss << execdata.m_codeseparator_pos; } hash_out = ss.GetSHA256(); return true;}template <class T>uint256 SignatureHash(const CScript& scriptCode, const T& txTo, unsigned int nIn, int nHashType, const CAmount& amount, SigVersion sigversion, const PrecomputedTransactionData* cache){ assert(nIn < txTo.vin.size()); if (sigversion == SigVersion::WITNESS_V0) { uint256 hashPrevouts; uint256 hashSequence; uint256 hashOutputs; const bool cacheready = cache && cache->m_bip143_segwit_ready; if (!(nHashType & SIGHASH_ANYONECANPAY)) { hashPrevouts = cacheready ? cache->hashPrevouts : SHA256Uint256(GetPrevoutsSHA256(txTo)); } if (!(nHashType & SIGHASH_ANYONECANPAY) && (nHashType & 0x1f) != SIGHASH_SINGLE && (nHashType & 0x1f) != SIGHASH_NONE) { hashSequence = cacheready ? cache->hashSequence : SHA256Uint256(GetSequencesSHA256(txTo)); } if ((nHashType & 0x1f) != SIGHASH_SINGLE && (nHashType & 0x1f) != SIGHASH_NONE) { hashOutputs = cacheready ? cache->hashOutputs : SHA256Uint256(GetOutputsSHA256(txTo)); } 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 << 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(); } // Check for invalid use of SIGHASH_SINGLE if ((nHashType & 0x1f) == SIGHASH_SINGLE) { if (nIn >= txTo.vout.size()) { // nOut out of range return uint256::ONE; } } // Wrapper to serialize only the necessary parts of the transaction being signed CTransactionSignatureSerializer<T> txTmp(txTo, scriptCode, nIn, nHashType); // Serialize and hash CHashWriter ss(SER_GETHASH, 0); ss << txTmp << nHashType; return ss.GetHash();}template <class T>bool GenericTransactionSignatureChecker<T>::VerifyECDSASignature(const std::vector<unsigned char>& vchSig, const CPubKey& pubkey, const uint256& sighash) const{ return pubkey.Verify(sighash, vchSig);}template <class T>bool GenericTransactionSignatureChecker<T>::VerifySchnorrSignature(Span<const unsigned char> sig, const XOnlyPubKey& pubkey, const uint256& sighash) const{ return pubkey.VerifySchnorr(sighash, sig);}template <class T>bool GenericTransactionSignatureChecker<T>::CheckECDSASignature(const std::vector<unsigned char>& vchSigIn, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const{ CPubKey pubkey(vchPubKey); if (!pubkey.IsValid()) return false; // Hash type is one byte tacked on to the end of the signature std::vector<unsigned char> vchSig(vchSigIn); if (vchSig.empty()) return false; int nHashType = vchSig.back(); vchSig.pop_back(); uint256 sighash = SignatureHash(scriptCode, *txTo, nIn, nHashType, amount, sigversion, this->txdata); if (!VerifyECDSASignature(vchSig, pubkey, sighash)) return false; return true;}template <class T>bool GenericTransactionSignatureChecker<T>::CheckSchnorrSignature(Span<const unsigned char> sig, Span<const unsigned char> pubkey_in, SigVersion sigversion, const ScriptExecutionData& execdata, ScriptError* serror) const{ assert(sigversion == SigVersion::TAPROOT || sigversion == SigVersion::TAPSCRIPT); // Schnorr signatures have 32-byte public keys. The caller is responsible for enforcing this. assert(pubkey_in.size() == 32); // Note that in Tapscript evaluation, empty signatures are treated specially (invalid signature that does not // abort script execution). This is implemented in EvalChecksigTapscript, which won't invoke // CheckSchnorrSignature in that case. In other contexts, they are invalid like every other signature with // size different from 64 or 65. if (sig.size() != 64 && sig.size() != 65) return set_error(serror, SCRIPT_ERR_SCHNORR_SIG_SIZE); XOnlyPubKey pubkey{pubkey_in}; uint8_t hashtype = SIGHASH_DEFAULT; if (sig.size() == 65) { hashtype = SpanPopBack(sig); if (hashtype == SIGHASH_DEFAULT) return set_error(serror, SCRIPT_ERR_SCHNORR_SIG_HASHTYPE); } uint256 sighash; assert(this->txdata); if (!SignatureHashSchnorr(sighash, execdata, *txTo, nIn, hashtype, sigversion, *this->txdata)) { return set_error(serror, SCRIPT_ERR_SCHNORR_SIG_HASHTYPE); } if (!VerifySchnorrSignature(sig, pubkey, sighash)) return set_error(serror, SCRIPT_ERR_SCHNORR_SIG); return true;}template <class T>bool GenericTransactionSignatureChecker<T>::CheckLockTime(const CScriptNum& nLockTime) const{ // There are two kinds of nLockTime: lock-by-blockheight // and lock-by-blocktime, distinguished by whether // nLockTime < LOCKTIME_THRESHOLD. // // We want to compare apples to apples, so fail the script // unless the type of nLockTime being tested is the same as // the nLockTime in the transaction. if (!( (txTo->nLockTime < LOCKTIME_THRESHOLD && nLockTime < LOCKTIME_THRESHOLD) || (txTo->nLockTime >= LOCKTIME_THRESHOLD && nLockTime >= LOCKTIME_THRESHOLD) )) return false; // Now that we know we're comparing apples-to-apples, the // comparison is a simple numeric one. if (nLockTime > (int64_t)txTo->nLockTime) return false; // Finally the nLockTime feature can be disabled and thus // CHECKLOCKTIMEVERIFY bypassed if every txin has been // finalized by setting nSequence to maxint. The // transaction would be allowed into the blockchain, making // the opcode ineffective. // // Testing if this vin is not final is sufficient to // prevent this condition. Alternatively we could test all // inputs, but testing just this input minimizes the data // required to prove correct CHECKLOCKTIMEVERIFY execution. if (CTxIn::SEQUENCE_FINAL == txTo->vin[nIn].nSequence) return false; return true;}template <class T>bool GenericTransactionSignatureChecker<T>::CheckSequence(const CScriptNum& nSequence) const{ // Relative lock times are supported by comparing the passed // in operand to the sequence number of the input. const int64_t txToSequence = (int64_t)txTo->vin[nIn].nSequence; // Fail if the transaction's version number is not set high // enough to trigger BIP 68 rules. if (static_cast<uint32_t>(txTo->nVersion) < 2) return false; // Sequence numbers with their most significant bit set are not // consensus constrained. Testing that the transaction's sequence // number do not have this bit set prevents using this property // to get around a CHECKSEQUENCEVERIFY check. if (txToSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) return false; // Mask off any bits that do not have consensus-enforced meaning // before doing the integer comparisons const uint32_t nLockTimeMask = CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG | CTxIn::SEQUENCE_LOCKTIME_MASK; const int64_t txToSequenceMasked = txToSequence & nLockTimeMask; const CScriptNum nSequenceMasked = nSequence & nLockTimeMask; // There are two kinds of nSequence: lock-by-blockheight // and lock-by-blocktime, distinguished by whether // nSequenceMasked < CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG. // // We want to compare apples to apples, so fail the script // unless the type of nSequenceMasked being tested is the same as // the nSequenceMasked in the transaction. if (!( (txToSequenceMasked < CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG && nSequenceMasked < CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) || (txToSequenceMasked >= CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG && nSequenceMasked >= CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) )) { return false; } // Now that we know we're comparing apples-to-apples, the // comparison is a simple numeric one. if (nSequenceMasked > txToSequenceMasked) return false; return true;}// explicit instantiationtemplate class GenericTransactionSignatureChecker<CTransaction>;template class GenericTransactionSignatureChecker<CMutableTransaction>;static bool ExecuteWitnessScript(const Span<const valtype>& stack_span, const CScript& scriptPubKey, unsigned int flags, SigVersion sigversion, const BaseSignatureChecker& checker, ScriptExecutionData& execdata, ScriptError* serror){ std::vector<valtype> stack{stack_span.begin(), stack_span.end()}; if (sigversion == SigVersion::TAPSCRIPT) { // OP_SUCCESSx processing overrides everything, including stack element size limits CScript::const_iterator pc = scriptPubKey.begin(); while (pc < scriptPubKey.end()) { opcodetype opcode; if (!scriptPubKey.GetOp(pc, opcode)) { // Note how this condition would not be reached if an unknown OP_SUCCESSx was found return set_error(serror, SCRIPT_ERR_BAD_OPCODE); } // New opcodes will be listed here. May use a different sigversion to modify existing opcodes. if (IsOpSuccess(opcode)) { if (flags & SCRIPT_VERIFY_DISCOURAGE_OP_SUCCESS) { return set_error(serror, SCRIPT_ERR_DISCOURAGE_OP_SUCCESS); } return set_success(serror); } } // Tapscript enforces initial stack size limits (altstack is empty here) if (stack.size() > MAX_STACK_SIZE) return set_error(serror, SCRIPT_ERR_STACK_SIZE); } // Disallow stack item size > MAX_SCRIPT_ELEMENT_SIZE in witness stack for (const valtype& elem : stack) { if (elem.size() > MAX_SCRIPT_ELEMENT_SIZE) return set_error(serror, SCRIPT_ERR_PUSH_SIZE); } // Run the script interpreter. if (!EvalScript(stack, scriptPubKey, flags, checker, sigversion, execdata, serror)) return false; // Scripts inside witness implicitly require cleanstack behaviour if (stack.size() != 1) return set_error(serror, SCRIPT_ERR_CLEANSTACK); if (!CastToBool(stack.back())) return set_error(serror, SCRIPT_ERR_EVAL_FALSE); return true;}static bool VerifyTaprootCommitment(const std::vector<unsigned char>& control, const std::vector<unsigned char>& program, const CScript& script, uint256& tapleaf_hash){ const int path_len = (control.size() - TAPROOT_CONTROL_BASE_SIZE) / TAPROOT_CONTROL_NODE_SIZE; const XOnlyPubKey p{uint256(std::vector<unsigned char>(control.begin() + 1, control.begin() + TAPROOT_CONTROL_BASE_SIZE))}; const XOnlyPubKey q{uint256(program)}; tapleaf_hash = (CHashWriter(HASHER_TAPLEAF) << uint8_t(control[0] & TAPROOT_LEAF_MASK) << script).GetSHA256(); uint256 k = tapleaf_hash; for (int i = 0; i < path_len; ++i) { CHashWriter ss_branch{HASHER_TAPBRANCH}; Span<const unsigned char> node(control.data() + TAPROOT_CONTROL_BASE_SIZE + TAPROOT_CONTROL_NODE_SIZE * i, TAPROOT_CONTROL_NODE_SIZE); if (std::lexicographical_compare(k.begin(), k.end(), node.begin(), node.end())) { ss_branch << k << node; } else { ss_branch << node << k; } k = ss_branch.GetSHA256(); } k = (CHashWriter(HASHER_TAPTWEAK) << MakeSpan(p) << k).GetSHA256(); return q.CheckPayToContract(p, k, control[0] & 1);}static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion, const std::vector<unsigned char>& program, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror, bool is_p2sh){ CScript exec_script; //!< Actually executed script (last stack item in P2WSH; implied P2PKH script in P2WPKH; leaf script in P2TR) Span<const valtype> stack{witness.stack}; ScriptExecutionData execdata; if (witversion == 0) { if (program.size() == WITNESS_V0_SCRIPTHASH_SIZE) { // BIP141 P2WSH: 32-byte witness v0 program (which encodes SHA256(script)) if (stack.size() == 0) { return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_WITNESS_EMPTY); } const valtype& script_bytes = SpanPopBack(stack); exec_script = CScript(script_bytes.begin(), script_bytes.end()); uint256 hash_exec_script; CSHA256().Write(&exec_script[0], exec_script.size()).Finalize(hash_exec_script.begin()); if (memcmp(hash_exec_script.begin(), program.data(), 32)) { return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_MISMATCH); } return ExecuteWitnessScript(stack, exec_script, flags, SigVersion::WITNESS_V0, checker, execdata, serror); } else if (program.size() == WITNESS_V0_KEYHASH_SIZE) { // BIP141 P2WPKH: 20-byte witness v0 program (which encodes Hash160(pubkey)) if (stack.size() != 2) { return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_MISMATCH); // 2 items in witness } exec_script << OP_DUP << OP_HASH160 << program << OP_EQUALVERIFY << OP_CHECKSIG; return ExecuteWitnessScript(stack, exec_script, flags, SigVersion::WITNESS_V0, checker, execdata, serror); } else { return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_WRONG_LENGTH); } } else if (witversion == 1 && program.size() == WITNESS_V1_TAPROOT_SIZE && !is_p2sh) { // BIP341 Taproot: 32-byte non-P2SH witness v1 program (which encodes a P2C-tweaked pubkey) if (!(flags & SCRIPT_VERIFY_TAPROOT)) return set_success(serror); if (stack.size() == 0) return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_WITNESS_EMPTY); if (stack.size() >= 2 && !stack.back().empty() && stack.back()[0] == ANNEX_TAG) { // Drop annex (this is non-standard; see IsWitnessStandard) const valtype& annex = SpanPopBack(stack); execdata.m_annex_hash = (CHashWriter(SER_GETHASH, 0) << annex).GetSHA256(); execdata.m_annex_present = true; } else { execdata.m_annex_present = false; } execdata.m_annex_init = true; if (stack.size() == 1) { // Key path spending (stack size is 1 after removing optional annex) if (!checker.CheckSchnorrSignature(stack.front(), program, SigVersion::TAPROOT, execdata, serror)) { return false; // serror is set } return set_success(serror); } else { // Script path spending (stack size is >1 after removing optional annex) const valtype& control = SpanPopBack(stack); const valtype& script_bytes = SpanPopBack(stack); exec_script = CScript(script_bytes.begin(), script_bytes.end()); if (control.size() < TAPROOT_CONTROL_BASE_SIZE || control.size() > TAPROOT_CONTROL_MAX_SIZE || ((control.size() - TAPROOT_CONTROL_BASE_SIZE) % TAPROOT_CONTROL_NODE_SIZE) != 0) { return set_error(serror, SCRIPT_ERR_TAPROOT_WRONG_CONTROL_SIZE); } if (!VerifyTaprootCommitment(control, program, exec_script, execdata.m_tapleaf_hash)) { return set_error(serror, SCRIPT_ERR_WITNESS_PROGRAM_MISMATCH); } execdata.m_tapleaf_hash_init = true; if ((control[0] & TAPROOT_LEAF_MASK) == TAPROOT_LEAF_TAPSCRIPT) { // Tapscript (leaf version 0xc0) execdata.m_validation_weight_left = ::GetSerializeSize(witness.stack, PROTOCOL_VERSION) + VALIDATION_WEIGHT_OFFSET; execdata.m_validation_weight_left_init = true; return ExecuteWitnessScript(stack, exec_script, flags, SigVersion::TAPSCRIPT, checker, execdata, serror); } if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_TAPROOT_VERSION) { return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_TAPROOT_VERSION); } return set_success(serror); } } else { if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM) { return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM); } // Other version/size/p2sh combinations return true for future softfork compatibility return true; } // There is intentionally no return statement here, to be able to use "control reaches end of non-void function" warnings to detect gaps in the logic above.}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 == nullptr) { witness = &emptyWitness; } bool hadWitness = false; set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR); if ((flags & SCRIPT_VERIFY_SIGPUSHONLY) != 0 && !scriptSig.IsPushOnly()) { return set_error(serror, SCRIPT_ERR_SIG_PUSHONLY); } // scriptSig and scriptPubKey must be evaluated sequentially on the same stack // rather than being simply concatenated (see CVE-2010-5141) std::vector<std::vector<unsigned char> > stack, stackCopy; 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, SigVersion::BASE, serror)) // serror is set return false; if (stack.empty()) return set_error(serror, SCRIPT_ERR_EVAL_FALSE); 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, /* is_p2sh */ false)) { 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()) { // scriptSig must be literals-only or validation fails if (!scriptSig.IsPushOnly()) return set_error(serror, SCRIPT_ERR_SIG_PUSHONLY); // Restore stack. swap(stack, stackCopy); // stack cannot be empty here, because if it was the // P2SH HASH <> EQUAL scriptPubKey would be evaluated with // an empty stack and the EvalScript above would return false. assert(!stack.empty()); const valtype& pubKeySerialized = stack.back(); CScript pubKey2(pubKeySerialized.begin(), pubKeySerialized.end()); popstack(stack); 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, /* is_p2sh */ true)) { 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). 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){ if (witversion == 0) { if (witprogram.size() == WITNESS_V0_KEYHASH_SIZE) return 1; if (witprogram.size() == WITNESS_V0_SCRIPTHASH_SIZE && 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); } if (scriptPubKey.IsPayToScriptHash() && scriptSig.IsPushOnly()) { CScript::const_iterator pc = scriptSig.begin(); std::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); } } return 0;}