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elements/src/script/interpreter.cpp

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <script/interpreter.h>
#include <consensus/consensus.h>
#include <crypto/ripemd160.h>
#include <crypto/sha1.h>
#include <crypto/sha256.h>
#include <pubkey.h>
#include <script/script.h>
#include <uint256.h>
extern "C" {
#include <simplicity/elements/env.h>
#include <simplicity/elements/exec.h>
#include <simplicity/errorCodes.h>
}
typedef std::vector<unsigned char> valtype;
// These asserts are consensus critical for elements tapscript arithmetic opcodes
static_assert(static_cast<uint64_t>(std::numeric_limits<int64_t>::max()) == UINT64_C(0x7FFFFFFFFFFFFFFF));
static_assert(static_cast<uint64_t>(std::numeric_limits<int64_t>::min()) == UINT64_C(0x8000000000000000));
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;
}
} // namespace
bool 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(size_t(int64_t(stack.size()) + int64_t{i})))
#define altstacktop(i) (altstack.at(size_t(int64_t(altstack.size()) + int64_t{i})))
static inline void popstack(std::vector<valtype>& stack)
{
if (stack.empty())
throw std::runtime_error("popstack(): stack empty");
stack.pop_back();
}
static inline int64_t cast_signed64(uint64_t v)
{
uint64_t int64_min = static_cast<uint64_t>(std::numeric_limits<int64_t>::min());
if (v >= int64_min)
return static_cast<int64_t>(v - int64_min) + std::numeric_limits<int64_t>::min();
return static_cast<int64_t>(v);
}
static inline int64_t read_le8_signed(const unsigned char* ptr)
{
return cast_signed64(ReadLE64(ptr));
}
static inline void push4_le(std::vector<valtype>& stack, uint32_t v)
{
uint32_t v_le = htole32_internal(v);
stack.emplace_back(reinterpret_cast<unsigned char*>(&v_le), reinterpret_cast<unsigned char*>(&v_le) + sizeof(v_le));
}
static inline void push8_le(std::vector<valtype>& stack, uint64_t v)
{
uint64_t v_le = htole64_internal(v);
stack.emplace_back(reinterpret_cast<unsigned char*>(&v_le), reinterpret_cast<unsigned char*>(&v_le) + sizeof(v_le));
}
static inline void pushasset(std::vector<valtype>& stack, const CConfidentialAsset& asset)
{
assert(!asset.IsNull());
stack.emplace_back(asset.vchCommitment.begin() + 1, asset.vchCommitment.end()); // Push asset without prefix
stack.emplace_back(asset.vchCommitment.begin(), asset.vchCommitment.begin() + 1); // Push prefix
}
static inline void pushvalue(std::vector<valtype>& stack, const CConfidentialValue& value)
{
valtype vchinpValue, vchValuePref;
if (value.IsNull()) {
// If value is null, explicitly push the explicit prefix 0x01
vchValuePref = {0x01};
vchinpValue.assign(8, 0x00);
} else if (value.IsExplicit()) {
// Convert BE to LE by using reverse iterator
vchValuePref.assign(value.vchCommitment.begin(), value.vchCommitment.begin() + 1);
vchinpValue.assign(value.vchCommitment.rbegin(), value.vchCommitment.rbegin() + 8);
} else { // (value.IsCommitment())
vchValuePref.assign(value.vchCommitment.begin(), value.vchCommitment.begin() + 1);
vchinpValue.assign(value.vchCommitment.begin() + 1, value.vchCommitment.end());
}
stack.push_back(std::move(vchinpValue)); // if value is null, 0(LE 8) is pushed
stack.push_back(std::move(vchValuePref)); // always push prefix
}
static inline void pushspk(std::vector<valtype>& stack, const CScript& scriptPubKey, const uint256& scriptPubKey_sha)
{
int witnessversion;
valtype witnessprogram;
if (scriptPubKey.IsWitnessProgram(witnessversion, witnessprogram)) {
stack.push_back(std::move(witnessprogram));
stack.push_back(CScriptNum(witnessversion).getvch());
} else {
stack.emplace_back(scriptPubKey_sha.begin(), scriptPubKey_sha.end());
stack.push_back(CScriptNum(-1).getvch());
}
}
/** Compute the outpoint flag(u8) for a given txin **/
template <class T>
inline unsigned char GetOutpointFlag(const T& txin)
{
return static_cast<unsigned char> ((!txin.assetIssuance.IsNull() ? (COutPoint::OUTPOINT_ISSUANCE_FLAG >> 24) : 0) |
(txin.m_is_pegin ? (COutPoint::OUTPOINT_PEGIN_FLAG >> 24) : 0));
}
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, unsigned int flags) {
if (vchSig.size() == 0) {
return false;
}
unsigned char nHashType = vchSig[vchSig.size() - 1] & (~(SIGHASH_ANYONECANPAY));
// ELEMENTS: Only allow SIGHASH_RANGEPROOF if the flag is set (after dynafed activation).
if ((flags & SCRIPT_SIGHASH_RANGEPROOF) == SCRIPT_SIGHASH_RANGEPROOF) {
nHashType = nHashType & (~(SIGHASH_RANGEPROOF));
}
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;
}
bool no_hash_byte = (flags & SCRIPT_NO_SIGHASH_BYTE) == SCRIPT_NO_SIGHASH_BYTE;
std::vector<unsigned char> vchSigCopy(vchSig.begin(), vchSig.begin() + vchSig.size());
// Push a dummy sighash byte to pass checks
if (no_hash_byte) {
vchSigCopy.push_back(SIGHASH_ALL);
}
if ((flags & (SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC)) != 0 && !IsValidSignatureEncoding(vchSigCopy)) {
return set_error(serror, SCRIPT_ERR_SIG_DER);
} else if ((flags & SCRIPT_VERIFY_LOW_S) != 0 && !IsLowDERSignature(vchSigCopy, serror)) {
// serror is set
return false;
} else if ((flags & SCRIPT_VERIFY_STRICTENC) != 0 && !IsDefinedHashtypeSignature(vchSigCopy, flags)) {
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;
}
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() const { return m_stack_size == 0; }
bool all_true() const { 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.
}
}
};
}
// Check the script has sufficient sigops budget for checksig(crypto) operation
inline bool update_validation_weight(ScriptExecutionData& execdata, ScriptError* serror)
{
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);
}
return true;
}
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, flags);
if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && vchSig.size())
return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL);
return true;
}
static bool EvalTapScriptCheckSigFromStack(const valtype& sig, const valtype& vchPubKey, ScriptExecutionData& execdata, unsigned int flags, const valtype& msg, SigVersion sigversion, ScriptError* serror, bool& success)
{
// This code follows the behaviour of EvalCheckSigTapscript
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.
if (!update_validation_weight(execdata, serror)) return false; // serror is set
}
if (vchPubKey.size() == 0) {
return set_error(serror, SCRIPT_ERR_PUBKEYTYPE);
} else if (vchPubKey.size() == 32) {
if (success) {
if (sig.size() != 64)
return set_error(serror, SCRIPT_ERR_SCHNORR_SIG_SIZE);
const XOnlyPubKey pubkey{vchPubKey};
if (!pubkey.VerifySchnorr(msg, sig))
return set_error(serror, SCRIPT_ERR_SCHNORR_SIG);
}
} 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;
}
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.
if (!update_validation_weight(execdata, serror)) return false; // serror is set
}
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);
}
const HashWriter HASHER_TAPLEAF_ELEMENTS = TaggedHash("TapLeaf/elements");
const HashWriter HASHER_TAPBRANCH_ELEMENTS = TaggedHash("TapBranch/elements");
const HashWriter HASHER_TAPSIGHASH_ELEMENTS = TaggedHash("TapSighash/elements");
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);
}
}
// ELEMENTS:
// commented out opcodes are re-enabled in Elements
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_LSHIFT ||
//opcode == OP_RSHIFT ||
opcode == OP_2MUL ||
opcode == OP_2DIV ||
opcode == OP_MUL ||
opcode == OP_DIV ||
opcode == OP_MOD
) {
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_CAT:
{
if (stack.size() < 2)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch1 = stacktop(-2);
valtype vch2 = stacktop(-1);
if (vch1.size() + vch2.size() > MAX_SCRIPT_ELEMENT_SIZE)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch3;
vch3.reserve(vch1.size() + vch2.size());
vch3.insert(vch3.end(), vch1.begin(), vch1.end());
vch3.insert(vch3.end(), vch2.begin(), vch2.end());
popstack(stack);
popstack(stack);
stack.push_back(vch3);
}
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;
//
// String operators
//
case OP_LEFT:
case OP_RIGHT:
{
if (stack.size() < 2)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch1 = stacktop(-2);
CScriptNum start(stacktop(-1), fRequireMinimal);
if (start < 0)
return set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR);
valtype vch2;
switch (opcode) {
case OP_RIGHT:
{
if (start >= vch1.size())
vch2 = vchZero;
else
vch2.insert(vch2.begin(), vch1.begin() + start.getint(), vch1.end());
break;
}
case OP_LEFT:
{
if (start >= vch1.size())
vch2 = vch1;
else
vch2.insert(vch2.begin(), vch1.begin(), vch1.begin() + start.getint());
break;
}
default:
{
assert(!"invalid opcode");
break;
}
}
popstack(stack);
popstack(stack);
stack.push_back(vch2);
}
break;
case OP_SUBSTR:
case OP_SUBSTR_LAZY:
{
if (stack.size() < 3)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch1 = stacktop(-3);
CScriptNum start(stacktop(-2), fRequireMinimal);
CScriptNum length(stacktop(-1), fRequireMinimal);
if (opcode == OP_SUBSTR_LAZY) {
if (start < 0)
start = 0;
if (length < 0)
length = 0;
if (start >= vch1.size()) {
popstack(stack);
popstack(stack);
popstack(stack);
stack.push_back(vchZero);
break;
}
if (length > MAX_SCRIPT_ELEMENT_SIZE)
length = MAX_SCRIPT_ELEMENT_SIZE;
// start + length cannot overflow because of the restrictions immediately above
if (start + length > vch1.size()) {
length = CScriptNum(vch1.size()) - start;
}
}
if (length < 0 || start < 0)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
if (start >= vch1.size())
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
if (length > vch1.size())
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
if ((start + length) > vch1.size())
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch2;
vch2.insert(vch2.begin(), vch1.begin() + start.getint(), vch1.begin() + (start + length).getint());
popstack(stack);
popstack(stack);
popstack(stack);
stack.push_back(vch2);
}
break;
//
// Bitwise logic
//
case OP_RSHIFT:
{
if (stack.size() < 2)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch1 = stacktop(-2);
CScriptNum bn(stacktop(-1), fRequireMinimal);
if (bn < 0)
return set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR);
unsigned int full_bytes = bn.getint() / 8;
unsigned int bits = bn.getint() % 8;
if (full_bytes >= vch1.size()) {
popstack(stack);
popstack(stack);
stack.push_back(vchZero);
break;
}
valtype vch2;
vch2.insert(vch2.begin(), vch1.begin() + full_bytes, vch1.end());
uint16_t temp = 0;
for (int i=(vch2.size()-1);i>=0;--i) {
temp = (vch2[i] << (8 - bits)) | ((temp << 8) & 0xff00);
vch2[i] = (temp & 0xff00) >> 8;
}
// 0x0fff >> 4 == 0x00ff or 0xff, reduce to minimal representation
while (!vch2.empty() && vch2.back() == 0)
vch2.pop_back();
popstack(stack);
popstack(stack);
stack.push_back(vch2);
}
break;
case OP_LSHIFT:
{
if (stack.size() < 2)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch1 = stacktop(-2);
CScriptNum bn(stacktop(-1), fRequireMinimal);
if (bn < 0)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
unsigned int full_bytes = bn.getint() / 8;
unsigned int bits = bn.getint() % 8;
if (vch1.size() + full_bytes + (bits ? 1 : 0) > MAX_SCRIPT_ELEMENT_SIZE)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch2;
vch2.reserve(vch1.size() + full_bytes + 1);
vch2.insert(vch2.end(), full_bytes, 0);
vch2.insert(vch2.end(), vch1.begin(), vch1.end());
vch2.insert(vch2.end(), 1, 0);
uint16_t temp = 0;
for (size_t i=0;i<vch2.size();++i) {
temp = (vch2[i] << bits) | (temp >> 8);
vch2[i] = temp & 0xff;
}
// reduce to minimal representation
while (!vch2.empty() && vch2.back() == 0)
vch2.pop_back();
popstack(stack);
popstack(stack);
stack.push_back(vch2);
}
break;
case OP_INVERT:
{
if (stack.size() < 1)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype& vch1 = stacktop(-1);
for (size_t i = 0; i < vch1.size(); ++i)
vch1[i] = ~vch1[i];
}
break;
case OP_AND:
{
// (x1 x2 -- x1 & x2)
if (stack.size() < 2)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype& vch1 = stacktop(-1);
valtype& vch2 = stacktop(-2);
if (vch1.size() != vch2.size())
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch3(vch1);
for (size_t i = 0; i < vch1.size(); i++)
vch3[i] &= vch2[i];
popstack(stack);
popstack(stack);
stack.push_back(vch3);
}
break;
case OP_OR:
{
// (x1 x2 -- x1 | x2)
if (stack.size() < 2)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype& vch1 = stacktop(-1);
valtype& vch2 = stacktop(-2);
if (vch1.size() != vch2.size())
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch3(vch1);
for (size_t i = 0; i < vch1.size(); i++)
vch3[i] |= vch2[i];
popstack(stack);
popstack(stack);
stack.push_back(vch3);
}
break;
case OP_XOR:
{
// (x1 x2 -- x1 ^ x2)
if (stack.size() < 2)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype& vch1 = stacktop(-1);
valtype& vch2 = stacktop(-2);
if (vch1.size() != vch2.size())
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vch3(vch1);
for (size_t i = 0; i < vch1.size(); i++)
vch3[i] ^= vch2[i];
popstack(stack);
popstack(stack);
stack.push_back(vch3);
}
break;
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, flags);
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;
case OP_DETERMINISTICRANDOM:
{
if (stack.size() < 3)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype vchSeed = stacktop(-3);
CScriptNum bnMin(stacktop(-2), fRequireMinimal);
CScriptNum bnMax(stacktop(-1), fRequireMinimal);
if (bnMin > bnMax)
return set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR);
if (bnMin == bnMax) {
popstack(stack);
popstack(stack);
popstack(stack);
stack.push_back(bnMin.getvch());
break;
}
// The range of the random source must be a multiple of the modulus
// to give every possible output value an equal possibility
uint64_t nMax = (bnMax-bnMin).getint();
uint64_t nRange = (std::numeric_limits<uint64_t>::max() / nMax) * nMax;
uint64_t nRand;
valtype vchHash(32, 0);
uint64_t nCounter = 0;
int nHashIndex = 3;
CSHA256 hasher;
hasher.Write(vchSeed.data(), vchSeed.size());
do {
if (nHashIndex >= 3) {
uint64_t le_counter = htole64_internal(nCounter);
CSHA256(hasher).Write((const unsigned char*)&le_counter, sizeof(nCounter)).Finalize(vchHash.data());
nHashIndex = 0;
nCounter++;
}
nRand = 0;
for (size_t i=0; i<8; ++i)
nRand |= ((uint64_t)vchHash[(nHashIndex*8) + i]) << (8*i);
nHashIndex++;
} while (nRand > nRange);
CScriptNum result(nRand % nMax);
result += bnMin.getint();
popstack(stack);
popstack(stack);
popstack(stack);
stack.push_back(result.getvch());
}
break;
case OP_CHECKSIGFROMSTACK:
case OP_CHECKSIGFROMSTACKVERIFY:
{
// (sig data pubkey -- bool)
if (stack.size() < 3)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype& vchSig = stacktop(-3);
valtype& vchData = stacktop(-2);
valtype& vchPubKey = stacktop(-1);
bool fSuccess;
// Different semantics for CHECKSIGFROMSTACK for taproot and pre-taproot
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0)
{
// Sigs from stack have no hash byte ever
if (!CheckSignatureEncoding(vchSig, (flags | SCRIPT_NO_SIGHASH_BYTE), serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) {
//serror is set
return false;
}
valtype vchHash(CSHA256::OUTPUT_SIZE);
CSHA256().Write(vchData.data(), vchData.size()).Finalize(vchHash.data());
uint256 hash(vchHash);
CPubKey pubkey(vchPubKey);
fSuccess = pubkey.Verify(hash, vchSig);
// CHECKSIGFROMSTACK in pre-tapscript cannot be failed.
if (!fSuccess)
return set_error(serror, SCRIPT_ERR_CHECKSIGVERIFY);
} else {
// New BIP 340 semantics for CHECKSIGFROMSTACK
if (!EvalTapScriptCheckSigFromStack(vchSig, vchPubKey, execdata, flags, vchData, sigversion, serror, fSuccess)) return false;
}
popstack(stack);
popstack(stack);
popstack(stack);
stack.push_back(fSuccess ? vchTrue : vchFalse);
if (opcode == OP_CHECKSIGFROMSTACKVERIFY)
{
if (fSuccess)
popstack(stack);
else
return set_error(serror, SCRIPT_ERR_CHECKSIGVERIFY);
}
}
break;
case OP_SHA256INITIALIZE: // (in -- sha256_ctx)
{
// OP_SHA256INITIALIZE is only available in Tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
if (stack.size() < 1)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
CSHA256 ctx;
valtype& vch = stacktop(-1);
if (!ctx.SafeWrite(vch.data(), vch.size()))
return set_error(serror, SCRIPT_ERR_SHA2_CONTEXT_WRITE);
popstack(stack);
stack.push_back(ctx.Save());
}
break;
case OP_SHA256UPDATE: // (sha256_ctx in -- sha256_ctx)
{
// OP_SHA256UPDATE is only available in Tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
if (stack.size() < 2)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
CSHA256 ctx;
valtype& vchCtx = stacktop(-2);
if (!ctx.Load(vchCtx))
return set_error(serror, SCRIPT_ERR_SHA2_CONTEXT_LOAD);
valtype& vch = stacktop(-1);
if (!ctx.SafeWrite(vch.data(), vch.size()))
return set_error(serror, SCRIPT_ERR_SHA2_CONTEXT_WRITE);
popstack(stack);
popstack(stack);
stack.push_back(ctx.Save());
}
break;
case OP_SHA256FINALIZE: // (sha256_ctx in -- hash)
{
// OP_SHA256FINALIZE is only available in Tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
if (stack.size() < 2)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype& vchCtx = stacktop(-2);
CSHA256 ctx;
if (!ctx.Load(vchCtx))
return set_error(serror, SCRIPT_ERR_SHA2_CONTEXT_LOAD);
valtype& vch = stacktop(-1);
if (!ctx.SafeWrite(vch.data(), vch.size()))
return set_error(serror, SCRIPT_ERR_SHA2_CONTEXT_WRITE);
valtype vchHash(CHash256::OUTPUT_SIZE);
ctx.Finalize(vchHash.data());
popstack(stack);
popstack(stack);
stack.push_back(std::move(vchHash));
}
break;
case OP_INSPECTINPUTOUTPOINT:
case OP_INSPECTINPUTASSET:
case OP_INSPECTINPUTVALUE:
case OP_INSPECTINPUTSCRIPTPUBKEY:
case OP_INSPECTINPUTSEQUENCE:
case OP_INSPECTINPUTISSUANCE:
{
// Input inspection opcodes only available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
if (stack.size() < 1)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
int idx = CScriptNum(stacktop(-1), fRequireMinimal).getint();
popstack(stack);
auto inps = checker.GetTxvIn();
const PrecomputedTransactionData *cache = checker.GetPrecomputedTransactionData();
// Return error if the evaluation context is unavailable
// TODO: Handle according to MissingDataBehavior
if (!inps || !cache || !cache->m_bip341_taproot_ready)
return set_error(serror, SCRIPT_ERR_INTROSPECT_CONTEXT_UNAVAILABLE);
const std::vector<CTxOut>& spent_outputs = cache->m_spent_outputs;
// This condition is ensured when m_spent_outputs_ready is set
// which is asserted when m_bip341_taproot_ready is set
assert(spent_outputs.size() == inps->size());
if (idx < 0 || static_cast<unsigned int>(idx) >= inps->size())
return set_error(serror, SCRIPT_ERR_INTROSPECT_INDEX_OUT_OF_BOUNDS);
const CTxIn& inp = inps->at(idx);
const CTxOut& spent_utxo = spent_outputs[idx];
switch (opcode)
{
case OP_INSPECTINPUTOUTPOINT:
{
// Push prev txid
stack.emplace_back(inp.prevout.hash.ToUint256().begin(), inp.prevout.hash.ToUint256().end());
push4_le(stack, inp.prevout.n);
// Push the outpoint flag
stack.emplace_back(1, GetOutpointFlag(inp));
break;
}
case OP_INSPECTINPUTASSET:
{
pushasset(stack, spent_utxo.nAsset);
break;
}
case OP_INSPECTINPUTVALUE:
{
pushvalue(stack, spent_utxo.nValue);
break;
}
case OP_INSPECTINPUTSCRIPTPUBKEY:
{
pushspk(stack, spent_utxo.scriptPubKey, cache->m_spent_output_spk_single_hashes[idx]);
break;
}
case OP_INSPECTINPUTSEQUENCE:
{
push4_le(stack, inp.nSequence);
break;
}
case OP_INSPECTINPUTISSUANCE:
{
if (!inp.assetIssuance.IsNull()) {
pushvalue(stack, inp.assetIssuance.nInflationKeys);
pushvalue(stack, inp.assetIssuance.nAmount);
// Next push Asset entropy
stack.emplace_back(inp.assetIssuance.assetEntropy.begin(), inp.assetIssuance.assetEntropy.end());
// Finally push blinding nonce
// By pushing the this order, we make sure that the stack top is empty
// iff there is no issuance.
stack.emplace_back(inp.assetIssuance.assetBlindingNonce.begin(), inp.assetIssuance.assetBlindingNonce.end());
} else { // No issuance
stack.push_back(vchFalse);
}
break;
}
default: assert(!"invalid opcode"); break;
}
}
break;
case OP_PUSHCURRENTINPUTINDEX:
{
// OP_PUSHCURRENTINPUTINDEX is available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
// Even tough this value should never 2^25(MAX_SIZE), this can set to any value in exotic custom contexts
// safe to check that this in 4 byte positive number before pushing it
// TODO: Handle according to MissingDataBehavior
if (checker.GetnIn() > MAX_SIZE)
return set_error(serror, SCRIPT_ERR_INTROSPECT_CONTEXT_UNAVAILABLE);
stack.push_back(CScriptNum(static_cast<int64_t>(checker.GetnIn())).getvch());
}
break;
case OP_INSPECTOUTPUTASSET:
case OP_INSPECTOUTPUTVALUE:
case OP_INSPECTOUTPUTNONCE:
case OP_INSPECTOUTPUTSCRIPTPUBKEY:
{
// Output instropsection codes only available post tapscript is available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
if (stack.size() < 1)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
int idx = CScriptNum(stacktop(-1), fRequireMinimal).getint();
popstack(stack);
auto outs = checker.GetTxvOut();
const PrecomputedTransactionData *cache = checker.GetPrecomputedTransactionData();
// Return error if the evaluation context is unavailable
// TODO: Handle according to MissingDataBehavior
if (!outs || !cache || !cache->m_bip341_taproot_ready)
return set_error(serror, SCRIPT_ERR_INTROSPECT_CONTEXT_UNAVAILABLE);
assert(cache->m_output_spk_single_hashes.size() == outs->size());
if (idx < 0 || static_cast<unsigned int>(idx) >= outs->size())
return set_error(serror, SCRIPT_ERR_INTROSPECT_INDEX_OUT_OF_BOUNDS);
const CTxOut& out = outs->at(idx);
switch (opcode)
{
case OP_INSPECTOUTPUTASSET:
{
pushasset(stack, out.nAsset);
break;
}
case OP_INSPECTOUTPUTVALUE:
{
pushvalue(stack, out.nValue);
break;
}
case OP_INSPECTOUTPUTNONCE:
{
if (out.nNonce.IsNull()) {
stack.push_back(vchFalse);
} else {
stack.emplace_back(out.nNonce.vchCommitment);
}
break;
}
case OP_INSPECTOUTPUTSCRIPTPUBKEY:
{
pushspk(stack, out.scriptPubKey, cache->m_output_spk_single_hashes[idx]);
break;
}
default: assert(!"invalid opcode"); break;
}
}
break;
case OP_INSPECTVERSION:
case OP_INSPECTLOCKTIME:
case OP_INSPECTNUMINPUTS:
case OP_INSPECTNUMOUTPUTS:
case OP_TXWEIGHT:
{
// Transaction introspection is available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
switch (opcode)
{
case OP_INSPECTVERSION:
{
push4_le(stack, static_cast<uint32_t>(checker.GetTxVersion()));
break;
}
case OP_INSPECTLOCKTIME:
{
push4_le(stack, checker.GetLockTime());
break;
}
case OP_INSPECTNUMINPUTS:
{
auto inps = checker.GetTxvIn();
// TODO: Handle according to MissingDataBehavior
if (!inps)
return set_error(serror, SCRIPT_ERR_INTROSPECT_CONTEXT_UNAVAILABLE);
auto num_ins = inps->size();
assert(num_ins <= MAX_SIZE);
stack.push_back(CScriptNum(static_cast<int64_t>(num_ins)).getvch());
break;
}
case OP_INSPECTNUMOUTPUTS:
{
auto outs = checker.GetTxvOut();
// TODO: Handle according to MissingDataBehavior
if (!outs)
return set_error(serror, SCRIPT_ERR_INTROSPECT_CONTEXT_UNAVAILABLE);
auto num_outs = outs->size();
assert(num_outs <= MAX_SIZE);
stack.push_back(CScriptNum(static_cast<int64_t>(num_outs)).getvch());
break;
}
case OP_TXWEIGHT:
{
const PrecomputedTransactionData *cache = checker.GetPrecomputedTransactionData();
// Return error if the evaluation context is unavailable
// TODO: Handle according to MissingDataBehavior
if (!cache || !cache->m_bip341_taproot_ready)
return set_error(serror, SCRIPT_ERR_INTROSPECT_CONTEXT_UNAVAILABLE);
push8_le(stack, cache->m_tx_weight);
break;
}
default: assert(!"invalid opcode"); break;
}
}
break;
case OP_ADD64:
case OP_SUB64:
case OP_MUL64:
case OP_DIV64:
case OP_LESSTHAN64:
case OP_LESSTHANOREQUAL64:
case OP_GREATERTHAN64:
case OP_GREATERTHANOREQUAL64:
{
// Opcodes only available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
if (stack.size() < 2)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype& vcha = stacktop(-2);
valtype& vchb = stacktop(-1);
if (vchb.size() != 8 || vcha.size() != 8)
return set_error(serror, SCRIPT_ERR_EXPECTED_8BYTES);
int64_t b = read_le8_signed(vchb.data());
int64_t a = read_le8_signed(vcha.data());
switch(opcode)
{
case OP_ADD64:
if ((a > 0 && b > std::numeric_limits<int64_t>::max() - a) ||
(a < 0 && b < std::numeric_limits<int64_t>::min() - a))
stack.push_back(vchFalse);
else {
popstack(stack);
popstack(stack);
push8_le(stack, a + b);
stack.push_back(vchTrue);
}
break;
case OP_SUB64:
if ((b > 0 && a < std::numeric_limits<int64_t>::min() + b) ||
(b < 0 && a > std::numeric_limits<int64_t>::max() + b))
stack.push_back(vchFalse);
else {
popstack(stack);
popstack(stack);
push8_le(stack, a - b);
stack.push_back(vchTrue);
}
break;
case OP_MUL64:
if ((a > 0 && b > 0 && a > std::numeric_limits<int64_t>::max() / b) ||
(a > 0 && b < 0 && b < std::numeric_limits<int64_t>::min() / a) ||
(a < 0 && b > 0 && a < std::numeric_limits<int64_t>::min() / b) ||
(a < 0 && b < 0 && b < std::numeric_limits<int64_t>::max() / a))
stack.push_back(vchFalse);
else {
popstack(stack);
popstack(stack);
push8_le(stack, a * b);
stack.push_back(vchTrue);
}
break;
case OP_DIV64:
{
if (b == 0 || (b == -1 && a == std::numeric_limits<int64_t>::min())) { stack.push_back(vchFalse); break; }
int64_t r = a % b;
int64_t q = a / b;
if (r < 0 && b > 0) { r += b; q-=1;} // ensures that 0<=r<|b|
else if (r < 0 && b < 0) { r -= b; q+=1;} // ensures that 0<=r<|b|
popstack(stack);
popstack(stack);
push8_le(stack, r);
push8_le(stack, q);
stack.push_back(vchTrue);
}
break;
break;
case OP_LESSTHAN64: popstack(stack); popstack(stack); stack.push_back( (a < b) ? vchTrue : vchFalse ); break;
case OP_LESSTHANOREQUAL64: popstack(stack); popstack(stack); stack.push_back( (a <= b) ? vchTrue : vchFalse ); break;
case OP_GREATERTHAN64: popstack(stack); popstack(stack); stack.push_back( (a > b) ? vchTrue : vchFalse ); break;
case OP_GREATERTHANOREQUAL64: popstack(stack); popstack(stack); stack.push_back( (a >= b) ? vchTrue : vchFalse ); break;
default: assert(!"invalid opcode"); break;
}
}
break;
case OP_NEG64:
{
// Opcodes only available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
if (stack.size() < 1)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype& vcha = stacktop(-1);
if (vcha.size() != 8)
return set_error(serror, SCRIPT_ERR_EXPECTED_8BYTES);
int64_t a = read_le8_signed(vcha.data());
if (a == std::numeric_limits<int64_t>::min()) { stack.push_back(vchFalse); break; }
popstack(stack);
push8_le(stack, -a);
stack.push_back(vchTrue);
}
break;
case OP_SCRIPTNUMTOLE64:
{
// Opcodes only available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
if (stack.size() < 1)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
int64_t num = CScriptNum(stacktop(-1), fRequireMinimal).getint();
popstack(stack);
push8_le(stack, num);
}
break;
case OP_LE64TOSCRIPTNUM:
{
// Opcodes only available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
if (stack.size() < 1)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype& vchnum = stacktop(-1);
if (vchnum.size() != 8)
return set_error(serror, SCRIPT_ERR_EXPECTED_8BYTES);
valtype vchscript_num = CScriptNum(read_le8_signed(vchnum.data())).getvch();
if (vchscript_num.size() > CScriptNum::nDefaultMaxNumSize) {
return set_error(serror, SCRIPT_ERR_ARITHMETIC64);
} else {
popstack(stack);
stack.push_back(std::move(vchscript_num));
}
}
break;
case OP_LE32TOLE64:
{
// Opcodes only available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
if (stack.size() < 1)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
valtype& vchnum = stacktop(-1);
if (vchnum.size() != 4)
return set_error(serror, SCRIPT_ERR_ARITHMETIC64);
uint32_t num = ReadLE32(vchnum.data());
popstack(stack);
push8_le(stack, static_cast<int64_t>(num));
}
break;
case OP_ECMULSCALARVERIFY:
{
// OP_ECMULSCALARVERIFY is available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
valtype& vchRes = stacktop(-3);
valtype& vchGenerator = stacktop(-2);
valtype& vchScalar = stacktop(-1);
CPubKey pk(vchGenerator);
CPubKey res(vchRes);
if (!pk.IsCompressed() || !res.IsCompressed())
return set_error(serror, SCRIPT_ERR_PUBKEYTYPE);
if (!update_validation_weight(execdata, serror)) return false; // serror is set
if (vchScalar.size() != 32 || !res.TweakMulVerify(pk, uint256(vchScalar)))
return set_error(serror, SCRIPT_ERR_ECMULTVERIFYFAIL);
popstack(stack);
popstack(stack);
popstack(stack);
}
break;
//crypto opcodes
case OP_TWEAKVERIFY:
{
// OP_TWEAKVERIFY is available post tapscript
if (sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0) return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
valtype& vchTweakedKey = stacktop(-3);
valtype& vchTweak = stacktop(-2);
valtype& vchInternalKey = stacktop(-1);
if (vchTweakedKey.size() != CPubKey::COMPRESSED_SIZE || (vchTweakedKey[0] != 0x02 && vchTweakedKey[0] != 0x03)
|| vchInternalKey.size() != 32 || vchTweak.size() != 32)
return set_error(serror, SCRIPT_ERR_PUBKEYTYPE);
if (!update_validation_weight(execdata, serror)) return false; // serror is set
const XOnlyPubKey tweakedXOnlyKey{Span<const unsigned char>{vchTweakedKey.data() + 1, vchTweakedKey.data() + CPubKey::COMPRESSED_SIZE}};
const uint256 tweak(vchTweak);
const XOnlyPubKey internalKey{vchInternalKey};
if (!tweakedXOnlyKey.CheckPayToContract(internalKey, tweak, vchTweakedKey[0] & 1))
return set_error(serror, SCRIPT_ERR_ECMULTVERIFYFAIL);
popstack(stack);
popstack(stack);
popstack(stack);
}
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 fRangeproof; //!< whether the hashtype has the SIGHASH_RANGEPROOF flag set
const bool fHashSingle; //!< whether the hashtype is SIGHASH_SINGLE
const bool fHashNone; //!< whether the hashtype is SIGHASH_NONE
public:
CTransactionSignatureSerializer(const T& txToIn, const CScript& scriptCodeIn, unsigned int nInIn, int nHashTypeIn, unsigned int flags) :
txTo(txToIn), scriptCode(scriptCodeIn), nIn(nInIn),
fAnyoneCanPay(!!(nHashTypeIn & SIGHASH_ANYONECANPAY)),
fRangeproof(!!(flags & SCRIPT_SIGHASH_RANGEPROOF) && !!(nHashTypeIn & SIGHASH_RANGEPROOF)),
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(AsBytes(Span{&itBegin[0], size_t(it - itBegin - 1)}));
itBegin = it;
}
}
if (itBegin != scriptCode.end())
s.write(AsBytes(Span{&itBegin[0], size_t(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, int32_t{0});
else
::Serialize(s, txTo.vin[nInput].nSequence);
// Serialize the asset issuance object
if (!txTo.vin[nInput].assetIssuance.IsNull()) {
assert(g_con_elementsmode);
::Serialize(s, txTo.vin[nInput].assetIssuance);
}
}
/** 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 rangeproof
if (fRangeproof) {
if (nOutput < txTo.witness.vtxoutwit.size()) {
::Serialize(s, txTo.witness.vtxoutwit[nOutput].vchRangeproof);
::Serialize(s, txTo.witness.vtxoutwit[nOutput].vchSurjectionproof);
} else {
::Serialize(s, (unsigned char) 0);
::Serialize(s, (unsigned char) 0);
}
}
}
}
/** Serialize txTo */
template<typename S>
void Serialize(S &s) const {
// Serialize version
::Serialize(s, txTo.version);
// 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 outpoint flags of a tx. */
template <class T>
uint256 GetOutpointFlagsSHA256(const T& txTo)
{
HashWriter ss{};
for (const auto& txin : txTo.vin) {
ss << GetOutpointFlag(txin);
}
return ss.GetSHA256();
}
/** Compute the (single) SHA256 of the concatenation of all prevouts of a tx. */
template <class T>
uint256 GetPrevoutsSHA256(const T& txTo)
{
HashWriter ss{};
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)
{
HashWriter ss{};
for (const auto& txin : txTo.vin) {
ss << txin.nSequence;
}
return ss.GetSHA256();
}
/** Compute the (single) SHA256 of the concatenation of all issuances of a tx. */
// Used for segwitv0/taproot sighash calculation
template <class T>
uint256 GetIssuanceSHA256(const T& txTo)
{
HashWriter ss{};
for (const auto& txin : txTo.vin) {
if (txin.assetIssuance.IsNull())
ss << (unsigned char)0;
else
ss << txin.assetIssuance;
}
return ss.GetSHA256();
}
/** Compute the (single) SHA256 of the concatenation of all output witnesses
* (rangeproof and surjection proof) in `CTxWitness`*/
// Used in taphash calculation
template <class T>
uint256 GetOutputWitnessesSHA256(const T& txTo)
{
HashWriter ss{};
for (const auto& outwit : txTo.witness.vtxoutwit) {
ss << outwit;
}
return ss.GetSHA256();
}
/** Compute the (single) SHA256 of the concatenation of all input issuance witnesses
* (vchIssuanceAmountRangeproof and vchInflationKeysRangeproof proof) in `CTxInWitness`*/
// Used in taphash calculation
template <class T>
uint256 GetIssuanceRangeproofsSHA256(const T& txTo)
{
HashWriter ss{};
for (const auto& inwit : txTo.witness.vtxinwit) {
ss << inwit.vchIssuanceAmountRangeproof;
ss << inwit.vchInflationKeysRangeproof;
}
return ss.GetSHA256();
}
// Compute a (single) SHA256 of the concatenation of all outputs
template <class T>
uint256 GetOutputsSHA256(const T& txTo)
{
HashWriter ss{};
for (const auto& txout : txTo.vout) {
ss << txout;
}
return ss.GetSHA256();
}
/** Compute the (single) SHA256 of the concatenation of all asset and amounts commitments spent by a tx. */
// Elements TapHash only
uint256 GetSpentAssetsAmountsSHA256(const std::vector<CTxOut>& outputs_spent)
{
HashWriter ss{};
for (const auto& txout : outputs_spent) {
ss << txout.nAsset;
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)
{
HashWriter ss{};
for (const auto& txout : outputs_spent) {
ss << txout.scriptPubKey;
}
return ss.GetSHA256();
}
/** Compute the vector where each element is SHA256 of scriptPubKeys spent by a tx. */
std::vector<uint256> GetSpentScriptPubKeysSHA256(const std::vector<CTxOut>& outputs_spent)
{
std::vector<uint256> spent_spk_single_hashes;
spent_spk_single_hashes.reserve(outputs_spent.size());
for (const auto& txout : outputs_spent) {
// Normal serialization using the << operator would also serialize the length, therefore we directly write using CSHA256
uint256 spent_spk_single_hash;
CSHA256().Write(txout.scriptPubKey.data(), txout.scriptPubKey.size()).Finalize(spent_spk_single_hash.data());
spent_spk_single_hashes.push_back(std::move(spent_spk_single_hash));
}
return spent_spk_single_hashes;
}
/** Compute the vector where each element is SHA256 of output scriptPubKey of a tx. */
template <class T>
std::vector<uint256> GetOutputScriptPubKeysSHA256(const T& txTo)
{
std::vector<uint256> out_spk_single_hashes;
out_spk_single_hashes.reserve(txTo.vout.size());
for (const auto& txout : txTo.vout) {
// Normal serialization using the << operator would also serialize the length, therefore we directly write using CSHA256
uint256 out_spk_single_hash;
CSHA256().Write(txout.scriptPubKey.data(), txout.scriptPubKey.size()).Finalize(out_spk_single_hash.data());
out_spk_single_hashes.push_back(std::move(out_spk_single_hash));
}
return out_spk_single_hashes;
}
template <class T>
uint256 GetRangeproofsHash(const T& txTo) {
HashWriter ss{};
for (size_t i = 0; i < txTo.vout.size(); i++) {
if (i < txTo.witness.vtxoutwit.size()) {
ss << txTo.witness.vtxoutwit[i].vchRangeproof;
ss << txTo.witness.vtxoutwit[i].vchSurjectionproof;
} else {
ss << (unsigned char) 0;
ss << (unsigned char) 0;
}
}
return ss.GetHash();
}
} // namespace
template <class T>
void PrecomputedTransactionData::Init(const T& txTo, std::vector<CTxOut>&& spent_outputs, bool force)
{
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 = force;
bool uses_bip341_taproot = force;
for (size_t inpos = 0; inpos < txTo.vin.size() && !(uses_bip143_segwit && uses_bip341_taproot); ++inpos) {
if (inpos < txTo.witness.vtxinwit.size() && !txTo.witness.vtxinwit[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);
m_issuances_single_hash = GetIssuanceSHA256(txTo);
}
if (uses_bip143_segwit) {
hashPrevouts = SHA256Uint256(m_prevouts_single_hash);
hashSequence = SHA256Uint256(m_sequences_single_hash);
hashIssuance = SHA256Uint256(m_issuances_single_hash);
hashOutputs = SHA256Uint256(m_outputs_single_hash);
hashRangeproofs = GetRangeproofsHash(txTo);
m_bip143_segwit_ready = true;
}
if (uses_bip341_taproot && m_spent_outputs_ready) {
// line copied from GetTransactionWeight() in src/consensus/validation.h
// (we cannot directly use that function for type reasons)
m_tx_weight = ::GetSerializeSize(TX_NO_WITNESS(txTo)) * (WITNESS_SCALE_FACTOR - 1) + ::GetSerializeSize(TX_WITH_WITNESS(txTo));
m_outpoints_flag_single_hash = GetOutpointFlagsSHA256(txTo);
m_spent_asset_amounts_single_hash = GetSpentAssetsAmountsSHA256(m_spent_outputs);
m_issuance_rangeproofs_single_hash = GetIssuanceRangeproofsSHA256(txTo);
m_output_witnesses_single_hash = GetOutputWitnessesSHA256(txTo);
m_spent_scripts_single_hash = GetSpentScriptsSHA256(m_spent_outputs);
m_spent_output_spk_single_hashes = GetSpentScriptPubKeysSHA256(m_spent_outputs);
m_output_spk_single_hashes = GetOutputScriptPubKeysSHA256(txTo);
std::vector<rawElementsBuffer> simplicityRawAnnex(txTo.witness.vtxinwit.size());
std::vector<rawElementsInput> simplicityRawInput(txTo.vin.size());
for (size_t i = 0; i < txTo.vin.size(); ++i) {
simplicityRawInput[i].prevTxid = txTo.vin[i].prevout.hash.ToUint256().begin();
simplicityRawInput[i].prevIx = txTo.vin[i].prevout.n;
simplicityRawInput[i].sequence = txTo.vin[i].nSequence;
simplicityRawInput[i].txo.asset = m_spent_outputs[i].nAsset.vchCommitment.empty() ? nullptr : m_spent_outputs[i].nAsset.vchCommitment.data();
simplicityRawInput[i].txo.value = m_spent_outputs[i].nValue.vchCommitment.empty() ? nullptr : m_spent_outputs[i].nValue.vchCommitment.data();
simplicityRawInput[i].txo.scriptPubKey.buf = m_spent_outputs[i].scriptPubKey.data();
simplicityRawInput[i].txo.scriptPubKey.len = m_spent_outputs[i].scriptPubKey.size();
simplicityRawInput[i].issuance.blindingNonce = txTo.vin[i].assetIssuance.assetBlindingNonce.begin();
simplicityRawInput[i].issuance.assetEntropy = txTo.vin[i].assetIssuance.assetEntropy.begin();
simplicityRawInput[i].issuance.amount = txTo.vin[i].assetIssuance.nAmount.vchCommitment.empty() ? nullptr : txTo.vin[i].assetIssuance.nAmount.vchCommitment.data();
simplicityRawInput[i].issuance.inflationKeys = txTo.vin[i].assetIssuance.nInflationKeys.vchCommitment.empty() ? nullptr : txTo.vin[i].assetIssuance.nInflationKeys.vchCommitment.data();
simplicityRawInput[i].annex = nullptr;
if (i < txTo.witness.vtxinwit.size()) {
Span<const valtype> stack{txTo.witness.vtxinwit[i].scriptWitness.stack};
if (stack.size() >= 2 && !stack.back().empty() && stack.back()[0] == ANNEX_TAG) {
simplicityRawAnnex[i].buf = stack.back().data()+1;
simplicityRawAnnex[i].len = stack.back().size()-1;
simplicityRawInput[i].annex = &simplicityRawAnnex[i];
}
simplicityRawInput[i].issuance.amountRangePrf.buf = txTo.witness.vtxinwit[i].vchIssuanceAmountRangeproof.data();
simplicityRawInput[i].issuance.amountRangePrf.len = txTo.witness.vtxinwit[i].vchIssuanceAmountRangeproof.size();
simplicityRawInput[i].issuance.inflationKeysRangePrf.buf = txTo.witness.vtxinwit[i].vchInflationKeysRangeproof.data();
simplicityRawInput[i].issuance.inflationKeysRangePrf.len = txTo.witness.vtxinwit[i].vchInflationKeysRangeproof.size();
assert(!txTo.vin[i].m_is_pegin || ( txTo.witness.vtxinwit[i].m_pegin_witness.stack.size() >= 4 && txTo.witness.vtxinwit[i].m_pegin_witness.stack[2].size() == 32));
simplicityRawInput[i].pegin = txTo.vin[i].m_is_pegin ? txTo.witness.vtxinwit[i].m_pegin_witness.stack[2].data() : nullptr;
} else {
simplicityRawInput[i].issuance.amountRangePrf.buf = nullptr;
simplicityRawInput[i].issuance.amountRangePrf.len = 0;
simplicityRawInput[i].issuance.inflationKeysRangePrf.buf = nullptr;
simplicityRawInput[i].issuance.inflationKeysRangePrf.len = 0;
assert(!txTo.vin[i].m_is_pegin);
simplicityRawInput[i].pegin = nullptr;
}
}
std::vector<rawElementsOutput> simplicityRawOutput(txTo.vout.size());
for (size_t i = 0; i < txTo.vout.size(); ++i) {
simplicityRawOutput[i].asset = txTo.vout[i].nAsset.vchCommitment.empty() ? nullptr : txTo.vout[i].nAsset.vchCommitment.data();
simplicityRawOutput[i].value = txTo.vout[i].nValue.vchCommitment.empty() ? nullptr : txTo.vout[i].nValue.vchCommitment.data();
simplicityRawOutput[i].nonce = txTo.vout[i].nNonce.vchCommitment.empty() ? nullptr : txTo.vout[i].nNonce.vchCommitment.data();
simplicityRawOutput[i].scriptPubKey.buf = txTo.vout[i].scriptPubKey.data();
simplicityRawOutput[i].scriptPubKey.len = txTo.vout[i].scriptPubKey.size();
if (i < txTo.witness.vtxoutwit.size()) {
simplicityRawOutput[i].surjectionProof.buf = txTo.witness.vtxoutwit[i].vchSurjectionproof.data();
simplicityRawOutput[i].surjectionProof.len = txTo.witness.vtxoutwit[i].vchSurjectionproof.size();
simplicityRawOutput[i].rangeProof.buf = txTo.witness.vtxoutwit[i].vchRangeproof.data();
simplicityRawOutput[i].rangeProof.len = txTo.witness.vtxoutwit[i].vchRangeproof.size();
} else {
simplicityRawOutput[i].surjectionProof.buf = nullptr;
simplicityRawOutput[i].surjectionProof.len = 0;
simplicityRawOutput[i].rangeProof.buf = nullptr;
simplicityRawOutput[i].rangeProof.len = 0;
}
}
rawElementsTransaction simplicityRawTx;
uint256 rawHash = txTo.GetHash();
simplicityRawTx.txid = rawHash.begin();
simplicityRawTx.input = simplicityRawInput.data();
simplicityRawTx.numInputs = simplicityRawInput.size();
simplicityRawTx.output = simplicityRawOutput.data();
simplicityRawTx.numOutputs = simplicityRawOutput.size();
simplicityRawTx.version = (uint32_t)txTo.version;
simplicityRawTx.lockTime = txTo.nLockTime;
m_simplicity_tx_data = SimplicityTransactionUniquePtr(simplicity_elements_mallocTransaction(&simplicityRawTx));
m_bip341_taproot_ready = true;
}
}
void SimplicityTransactionDeleter::operator()(elementsTransaction* ptr) const {
simplicity_elements_freeTransaction(ptr);
}
template <class T>
PrecomputedTransactionData::PrecomputedTransactionData(const T& txTo)
: PrecomputedTransactionData(uint256{})
{
Init(txTo, {});
}
// explicit instantiation
template void PrecomputedTransactionData::Init(const CTransaction& txTo, std::vector<CTxOut>&& spent_outputs, bool force);
template void PrecomputedTransactionData::Init(const CMutableTransaction& txTo, std::vector<CTxOut>&& spent_outputs, bool force);
template PrecomputedTransactionData::PrecomputedTransactionData(const CTransaction& txTo);
template PrecomputedTransactionData::PrecomputedTransactionData(const CMutableTransaction& txTo);
PrecomputedTransactionData::PrecomputedTransactionData(const uint256& hash_genesis_block)
: m_hash_genesis_block(hash_genesis_block)
, m_tapsighash_hasher(HashWriter(HASHER_TAPSIGHASH_ELEMENTS) << hash_genesis_block << hash_genesis_block) {}
static bool HandleMissingData(MissingDataBehavior mdb)
{
switch (mdb) {
case MissingDataBehavior::ASSERT_FAIL:
assert(!"Missing data");
break;
case MissingDataBehavior::FAIL:
return false;
}
assert(!"Unknown MissingDataBehavior value");
}
template<typename T>
bool SignatureHashSchnorr(uint256& hash_out, ScriptExecutionData& execdata, const T& tx_to, uint32_t in_pos, uint8_t hash_type, SigVersion sigversion, const PrecomputedTransactionData& cache, MissingDataBehavior mdb)
{
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());
if (!(cache.m_bip341_taproot_ready && cache.m_spent_outputs_ready)) {
return HandleMissingData(mdb);
}
HashWriter ss = cache.m_tapsighash_hasher;
// no epoch in elements taphash
// 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.version;
ss << tx_to.nLockTime;
if (input_type != SIGHASH_ANYONECANPAY) {
ss << cache.m_outpoints_flag_single_hash;
ss << cache.m_prevouts_single_hash;
ss << cache.m_spent_asset_amounts_single_hash;
// Why is nNonce not included in sighash?(both in ACP and non ACP case)
//
// Nonces are not serialized into utxo database. As a consequence, after restarting the node,
// all nonces in the utxoset are cleared which results in a inconsistent view for nonces for
// nodes that did not restart. See https://github.com/ElementsProject/elements/issues/1004 for details
ss << cache.m_spent_scripts_single_hash;
ss << cache.m_sequences_single_hash;
ss << cache.m_issuances_single_hash;
ss << cache.m_issuance_rangeproofs_single_hash;
}
if (output_type == SIGHASH_ALL) {
ss << cache.m_outputs_single_hash;
ss << cache.m_output_witnesses_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 << GetOutpointFlag(tx_to.vin[in_pos]);
ss << tx_to.vin[in_pos].prevout;
ss << cache.m_spent_outputs[in_pos].nAsset;
ss << cache.m_spent_outputs[in_pos].nValue;
ss << cache.m_spent_outputs[in_pos].scriptPubKey;
ss << tx_to.vin[in_pos].nSequence;
if (tx_to.vin[in_pos].assetIssuance.IsNull()) {
ss << (unsigned char)0;
} else {
ss << tx_to.vin[in_pos].assetIssuance;
HashWriter sha_single_input_issuance_witness{};
sha_single_input_issuance_witness << tx_to.witness.vtxinwit[in_pos].vchIssuanceAmountRangeproof;
sha_single_input_issuance_witness << tx_to.witness.vtxinwit[in_pos].vchInflationKeysRangeproof;
ss << sha_single_input_issuance_witness.GetSHA256();
}
} 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;
if (!execdata.m_output_hash) {
HashWriter sha_single_output{};
sha_single_output << tx_to.vout[in_pos];
execdata.m_output_hash = sha_single_output.GetSHA256();
}
ss << execdata.m_output_hash.value();
// ELEMENTS
if (!execdata.m_output_witness_hash) {
HashWriter sha_single_output_witness{};
sha_single_output_witness << tx_to.witness.vtxoutwit[in_pos];
execdata.m_output_witness_hash = sha_single_output_witness.GetSHA256();
}
ss << execdata.m_output_witness_hash.value();
}
// 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, int32_t nHashType, const CConfidentialValue& amount, SigVersion sigversion, unsigned int flags, const PrecomputedTransactionData* cache)
{
assert(nIn < txTo.vin.size());
if (sigversion == SigVersion::WITNESS_V0) {
uint256 hashPrevouts;
uint256 hashSequence;
uint256 hashIssuance;
uint256 hashOutputs;
uint256 hashRangeproofs;
const bool cacheready = cache && cache->m_bip143_segwit_ready;
bool fRangeproof = !!(flags & SCRIPT_SIGHASH_RANGEPROOF) && !!(nHashType & SIGHASH_RANGEPROOF);
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 & SIGHASH_ANYONECANPAY)) {
hashIssuance = cacheready ? cache->hashIssuance : SHA256Uint256(GetIssuanceSHA256(txTo));
}
if ((nHashType & 0x1f) != SIGHASH_SINGLE && (nHashType & 0x1f) != SIGHASH_NONE) {
hashOutputs = cacheready ? cache->hashOutputs : SHA256Uint256(GetOutputsSHA256(txTo));
if (fRangeproof) {
hashRangeproofs = cacheready ? cache->hashRangeproofs : GetRangeproofsHash(txTo);
}
} else if ((nHashType & 0x1f) == SIGHASH_SINGLE && nIn < txTo.vout.size()) {
HashWriter ss{};
ss << txTo.vout[nIn];
hashOutputs = ss.GetHash();
if (fRangeproof) {
HashWriter ss{};
if (nIn < txTo.witness.vtxoutwit.size()) {
ss << txTo.witness.vtxoutwit[nIn].vchRangeproof;
ss << txTo.witness.vtxoutwit[nIn].vchSurjectionproof;
} else {
ss << (unsigned char) 0;
ss << (unsigned char) 0;
}
hashRangeproofs = ss.GetHash();
}
}
HashWriter ss{};
// Version
ss << txTo.version;
// Input prevouts/nSequence (none/all, depending on flags)
ss << hashPrevouts;
ss << hashSequence;
if (g_con_elementsmode) {
ss << hashIssuance;
}
// 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;
if (g_con_elementsmode) {
ss << amount;
} else {
ss << amount.GetAmount();
}
ss << txTo.vin[nIn].nSequence;
if (!txTo.vin[nIn].assetIssuance.IsNull()) {
assert(g_con_elementsmode);
ss << txTo.vin[nIn].assetIssuance;
}
// Outputs (none/one/all, depending on flags)
ss << hashOutputs;
if (fRangeproof) {
// This addition must be conditional because it was added after
// the segwit sighash was specified.
ss << hashRangeproofs;
}
// 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, flags);
// Serialize and hash
HashWriter ss{};
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, unsigned int flags) 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();
// Witness sighashes need the amount.
if (sigversion == SigVersion::WITNESS_V0 && amount.IsNull()) return HandleMissingData(m_mdb);
uint256 sighash = SignatureHash(scriptCode, *txTo, nIn, nHashType, amount, sigversion, flags, 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, 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;
if (!this->txdata) return HandleMissingData(m_mdb);
if (!SignatureHashSchnorr(sighash, execdata, *txTo, nIn, hashtype, sigversion, *this->txdata, m_mdb)) {
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 in IsFinalTx()
// 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 (txTo->version < 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;
}
template <class T>
uint32_t GenericTransactionSignatureChecker<T>::GetLockTime() const
{
return txTo->nLockTime;
}
template <class T>
int32_t GenericTransactionSignatureChecker<T>::GetTxVersion() const
{
return txTo->version;
}
template <class T>
const std::vector<CTxIn>* GenericTransactionSignatureChecker<T>::GetTxvIn() const
{
return &(txTo->vin);
}
template <class T>
const std::vector<CTxOut>* GenericTransactionSignatureChecker<T>::GetTxvOut() const
{
return &(txTo->vout);
}
template <class T>
const PrecomputedTransactionData* GenericTransactionSignatureChecker<T>::GetPrecomputedTransactionData() const
{
return txdata;
}
template <class T>
uint32_t GenericTransactionSignatureChecker<T>::GetnIn() const
{
return nIn;
}
template <class T>
bool GenericTransactionSignatureChecker<T>::CheckSimplicity(const valtype& program, const valtype& witness, const rawElementsTapEnv& simplicityRawTap, int64_t budget, ScriptError* serror) const
{
simplicity_err error;
elementsTapEnv* simplicityTapEnv = simplicity_elements_mallocTapEnv(&simplicityRawTap);
assert(txdata->m_simplicity_tx_data);
assert(simplicityTapEnv);
if (!simplicity_elements_execSimplicity(&error, nullptr, txdata->m_simplicity_tx_data.get(), nIn, simplicityTapEnv, txdata->m_hash_genesis_block.data(), 0, budget, nullptr, program.data(), program.size(), witness.data(), witness.size())) {
assert(!"simplicity_elements_execSimplicity internal error");
}
simplicity_elements_freeTapEnv(simplicityTapEnv);
switch (error) {
case SIMPLICITY_NO_ERROR: return set_success(serror);
case SIMPLICITY_ERR_MALLOC:
case SIMPLICITY_ERR_NOT_YET_IMPLEMENTED:
assert(!"simplicity_elements_execSimplicity internal error");
break;
case SIMPLICITY_ERR_DATA_OUT_OF_RANGE: return set_error(serror, SCRIPT_ERR_SIMPLICITY_DATA_OUT_OF_RANGE);
case SIMPLICITY_ERR_DATA_OUT_OF_ORDER: return set_error(serror, SCRIPT_ERR_SIMPLICITY_DATA_OUT_OF_ORDER);
case SIMPLICITY_ERR_FAIL_CODE: return set_error(serror, SCRIPT_ERR_SIMPLICITY_FAIL_CODE);
case SIMPLICITY_ERR_RESERVED_CODE: return set_error(serror, SCRIPT_ERR_SIMPLICITY_RESERVED_CODE);
case SIMPLICITY_ERR_HIDDEN: return set_error(serror, SCRIPT_ERR_SIMPLICITY_HIDDEN);
case SIMPLICITY_ERR_BITSTREAM_EOF: return set_error(serror, SCRIPT_ERR_SIMPLICITY_BITSTREAM_EOF);
case SIMPLICITY_ERR_BITSTREAM_TRAILING_BYTES: return set_error(serror, SCRIPT_ERR_SIMPLICITY_BITSTREAM_TRAILING_BYTES);
case SIMPLICITY_ERR_BITSTREAM_ILLEGAL_PADDING: return set_error(serror, SCRIPT_ERR_SIMPLICITY_BITSTREAM_ILLEGAL_PADDING);
case SIMPLICITY_ERR_TYPE_INFERENCE_UNIFICATION: return set_error(serror, SCRIPT_ERR_SIMPLICITY_TYPE_INFERENCE_UNIFICATION);
case SIMPLICITY_ERR_TYPE_INFERENCE_OCCURS_CHECK: return set_error(serror, SCRIPT_ERR_SIMPLICITY_TYPE_INFERENCE_OCCURS_CHECK);
case SIMPLICITY_ERR_TYPE_INFERENCE_NOT_PROGRAM: return set_error(serror, SCRIPT_ERR_SIMPLICITY_TYPE_INFERENCE_NOT_PROGRAM);
case SIMPLICITY_ERR_WITNESS_EOF: return set_error(serror, SCRIPT_ERR_SIMPLICITY_WITNESS_EOF);
case SIMPLICITY_ERR_WITNESS_TRAILING_BYTES: return set_error(serror, SCRIPT_ERR_SIMPLICITY_WITNESS_TRAILING_BYTES);
case SIMPLICITY_ERR_WITNESS_ILLEGAL_PADDING: return set_error(serror, SCRIPT_ERR_SIMPLICITY_WITNESS_ILLEGAL_PADDING);
case SIMPLICITY_ERR_UNSHARED_SUBEXPRESSION: return set_error(serror, SCRIPT_ERR_SIMPLICITY_UNSHARED_SUBEXPRESSION);
case SIMPLICITY_ERR_CMR: return set_error(serror, SCRIPT_ERR_SIMPLICITY_CMR);
case SIMPLICITY_ERR_EXEC_BUDGET: return set_error(serror, SCRIPT_ERR_SIMPLICITY_EXEC_BUDGET);
case SIMPLICITY_ERR_EXEC_MEMORY: return set_error(serror, SCRIPT_ERR_SIMPLICITY_EXEC_MEMORY);
case SIMPLICITY_ERR_EXEC_JET: return set_error(serror, SCRIPT_ERR_SIMPLICITY_EXEC_JET);
case SIMPLICITY_ERR_EXEC_ASSERT: return set_error(serror, SCRIPT_ERR_SIMPLICITY_EXEC_ASSERT);
case SIMPLICITY_ERR_ANTIDOS: return set_error(serror, SCRIPT_ERR_SIMPLICITY_ANTIDOS);
case SIMPLICITY_ERR_HIDDEN_ROOT: return set_error(serror, SCRIPT_ERR_SIMPLICITY_HIDDEN_ROOT);
case SIMPLICITY_ERR_AMR: return set_error(serror, SCRIPT_ERR_SIMPLICITY_AMR);
case SIMPLICITY_ERR_OVERWEIGHT: return set_error(serror, SCRIPT_ERR_SIMPLICITY_OVERWEIGHT);
default: return set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR);
}
}
// explicit instantiation
template class GenericTransactionSignatureChecker<CTransaction>;
template class GenericTransactionSignatureChecker<CMutableTransaction>;
static bool ExecuteWitnessScript(const Span<const valtype>& stack_span, const CScript& exec_script, 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 = exec_script.begin();
while (pc < exec_script.end()) {
opcodetype opcode;
if (!exec_script.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, exec_script, 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;
}
uint256 ComputeTapleafHash(uint8_t leaf_version, Span<const unsigned char> script)
{
return (HashWriter{HASHER_TAPLEAF_ELEMENTS} << leaf_version << CompactSizeWriter(script.size()) << script).GetSHA256();
}
uint256 ComputeTapbranchHash(Span<const unsigned char> a, Span<const unsigned char> b)
{
HashWriter ss_branch{HASHER_TAPBRANCH_ELEMENTS};
if (std::lexicographical_compare(a.begin(), a.end(), b.begin(), b.end())) {
ss_branch << a << b;
} else {
ss_branch << b << a;
}
return ss_branch.GetSHA256();
}
uint256 ComputeTaprootMerkleRoot(Span<const unsigned char> control, const uint256& tapleaf_hash)
{
assert(control.size() >= TAPROOT_CONTROL_BASE_SIZE);
assert(control.size() <= TAPROOT_CONTROL_MAX_SIZE);
assert((control.size() - TAPROOT_CONTROL_BASE_SIZE) % TAPROOT_CONTROL_NODE_SIZE == 0);
const int path_len = (control.size() - TAPROOT_CONTROL_BASE_SIZE) / TAPROOT_CONTROL_NODE_SIZE;
uint256 k = tapleaf_hash;
for (int i = 0; i < path_len; ++i) {
Span node{Span{control}.subspan(TAPROOT_CONTROL_BASE_SIZE + TAPROOT_CONTROL_NODE_SIZE * i, TAPROOT_CONTROL_NODE_SIZE)};
k = ComputeTapbranchHash(k, node);
}
return k;
}
static bool VerifyTaprootCommitment(const std::vector<unsigned char>& control, const std::vector<unsigned char>& program, const uint256& tapleaf_hash)
{
assert(control.size() >= TAPROOT_CONTROL_BASE_SIZE);
assert(program.size() >= uint256::size());
//! The internal pubkey (x-only, so no Y coordinate parity).
const XOnlyPubKey p{Span{control}.subspan(1, TAPROOT_CONTROL_BASE_SIZE - 1)};
//! The output pubkey (taken from the scriptPubKey).
const XOnlyPubKey q{program};
// Compute the Merkle root from the leaf and the provided path.
const uint256 merkle_root = ComputeTaprootMerkleRoot(control, tapleaf_hash);
// Verify that the output pubkey matches the tweaked internal pubkey, after correcting for parity.
return q.CheckTapTweak(p, merkle_root, 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 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.data(), 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 = (HashWriter{} << 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 = SpanPopBack(stack);
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);
}
execdata.m_tapleaf_hash = ComputeTapleafHash(control[0] & TAPROOT_LEAF_MASK, script);
if (!VerifyTaprootCommitment(control, program, 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 0xc4)
exec_script = CScript(script.begin(), script.end());
execdata.m_validation_weight_left = ::GetSerializeSize(witness.stack) + 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_SIMPLICITY) && (control[0] & TAPROOT_LEAF_MASK) == TAPROOT_LEAF_TAPSIMPLICITY) {
if (stack.size() != 2 || script.size() != 32) return set_error(serror, SCRIPT_ERR_SIMPLICITY_WRONG_LENGTH);
// Tapsimplicity (leaf version 0xbe)
const valtype& simplicity_program = SpanPopBack(stack);
const valtype& simplicity_witness = SpanPopBack(stack);
const int64_t budget = ::GetSerializeSize(witness.stack) + VALIDATION_WEIGHT_OFFSET;
rawElementsTapEnv simplicityRawTap;
simplicityRawTap.controlBlock = control.data();
simplicityRawTap.pathLen = (control.size() - TAPROOT_CONTROL_BASE_SIZE) / TAPROOT_CONTROL_NODE_SIZE;
simplicityRawTap.scriptCMR = script.data();
return checker.CheckSimplicity(simplicity_program, simplicity_witness, simplicityRawTap, budget, 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 (!is_p2sh && CScript::IsPayToAnchor(witversion, program)) {
return true;
} 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;
}
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