// Copyright (c) 2009-2010 Satoshi Nakamoto

// Copyright (c) 2009-2016 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 "interpreter.h"

#include "primitives/transaction.h"

#include "crypto/ripemd160.h"

#include "crypto/sha1.h"

#include "crypto/sha256.h"

#include "pubkey.h"

#include "script/script.h"

#include "uint256.h"

typedef std::vector<unsigned char> valtype;

namespace {

inline bool set_success(ScriptError* ret)

{

if (ret)

*ret = SCRIPT_ERR_OK;

return true;

}

inline bool set_error(ScriptError* ret, const ScriptError serror)

{

if (ret)

*ret = serror;

return false;

}

} // 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(stack.size()+(i)))

#define altstacktop(i) (altstack.at(altstack.size()+(i)))

static inline void popstack(std::vector<valtype>& stack)

{

if (stack.empty())

throw std::runtime_error("popstack(): stack empty");

stack.pop_back();

}

bool static IsCompressedOrUncompressedPubKey(const valtype &vchPubKey) {

if (vchPubKey.size() < 33) {

// Non-canonical public key: too short

return false;

}

if (vchPubKey[0] == 0x04) {

if (vchPubKey.size() != 65) {

// Non-canonical public key: invalid length for uncompressed key

return false;

}

} else if (vchPubKey[0] == 0x02 || vchPubKey[0] == 0x03) {

if (vchPubKey.size() != 33) {

// 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() != 33) {

// 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 integers (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);

}

std::vector<unsigned char> vchSigCopy(vchSig.begin(), vchSig.begin() + vchSig.size() - 1);

if (!CPubKey::CheckLowS(vchSigCopy)) {

return set_error(serror, SCRIPT_ERR_SIG_HIGH_S);

}

return true;

}

bool static IsDefinedHashtypeSignature(const valtype &vchSig) {

if (vchSig.size() == 0) {

return false;

}

unsigned char nHashType = vchSig[vchSig.size() - 1] & (~(SIGHASH_ANYONECANPAY));

if (nHashType < SIGHASH_ALL || nHashType > SIGHASH_SINGLE)

return false;

return true;

}

bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror) {

// Empty signature. Not strictly DER encoded, but allowed to provide a

// compact way to provide an invalid signature for use with CHECK(MULTI)SIG

if (vchSig.size() == 0) {

return true;

}

if ((flags & (SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC)) != 0 && !IsValidSignatureEncoding(vchSig)) {

return set_error(serror, SCRIPT_ERR_SIG_DER);

} else if ((flags & SCRIPT_VERIFY_LOW_S) != 0 && !IsLowDERSignature(vchSig, serror)) {

// serror is set

return false;

} else if ((flags & SCRIPT_VERIFY_STRICTENC) != 0 && !IsDefinedHashtypeSignature(vchSig)) {

return set_error(serror, SCRIPT_ERR_SIG_HASHTYPE);

}

return true;

}

bool static CheckPubKeyEncoding(const valtype &vchPubKey, unsigned int flags, const SigVersion &sigversion, ScriptError* serror) {

if ((flags & SCRIPT_VERIFY_STRICTENC) != 0 && !IsCompressedOrUncompressedPubKey(vchPubKey)) {

return set_error(serror, SCRIPT_ERR_PUBKEYTYPE);

}

// Only compressed keys are accepted in segwit

if ((flags & SCRIPT_VERIFY_WITNESS_PUBKEYTYPE) != 0 && sigversion == SIGVERSION_WITNESS_V0 && !IsCompressedPubKey(vchPubKey)) {

return set_error(serror, SCRIPT_ERR_WITNESS_PUBKEYTYPE);

}

return true;

}

bool static CheckMinimalPush(const valtype& data, opcodetype opcode) {

if (data.size() == 0) {

// Could have used OP_0.

return opcode == OP_0;

} else if (data.size() == 1 && data[0] >= 1 && data[0] <= 16) {

// Could have used OP_1 .. OP_16.

return opcode == OP_1 + (data[0] - 1);

} else if (data.size() == 1 && data[0] == 0x81) {

// Could have used OP_1NEGATE.

return opcode == OP_1NEGATE;

} else if (data.size() <= 75) {

// Could have used a direct push (opcode indicating number of bytes pushed + those bytes).

return opcode == data.size();

} else if (data.size() <= 255) {

// Could have used OP_PUSHDATA.

return opcode == OP_PUSHDATA1;

} else if (data.size() <= 65535) {

// Could have used OP_PUSHDATA2.

return opcode == OP_PUSHDATA2;

}

return true;

}

bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror)

{

static const CScriptNum bnZero(0);

static const CScriptNum bnOne(1);

// 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);

CScript::const_iterator pc = script.begin();

CScript::const_iterator pend = script.end();

CScript::const_iterator pbegincodehash = script.begin();

opcodetype opcode;

valtype vchPushValue;

std::vector<bool> vfExec;

std::vector<valtype> altstack;

set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR);

if (script.size() > MAX_SCRIPT_SIZE)

return set_error(serror, SCRIPT_ERR_SCRIPT_SIZE);

int nOpCount = 0;

bool fRequireMinimal = (flags & SCRIPT_VERIFY_MINIMALDATA) != 0;

try

{

while (pc < pend)

{

bool fExec = !count(vfExec.begin(), vfExec.end(), false);

//

// 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);

// Note how OP_RESERVED does not count towards the opcode limit.

if (opcode > OP_16 && ++nOpCount > MAX_OPS_PER_SCRIPT)

return set_error(serror, SCRIPT_ERR_OP_COUNT);

if (opcode == OP_CAT ||

opcode == OP_SUBSTR ||

opcode == OP_LEFT ||

opcode == OP_RIGHT ||

opcode == OP_INVERT ||

opcode == OP_AND ||

opcode == OP_OR ||

opcode == OP_XOR ||

opcode == OP_2MUL ||

opcode == OP_2DIV ||

opcode == OP_MUL ||

opcode == OP_DIV ||

opcode == OP_MOD ||

opcode == OP_LSHIFT ||

opcode == OP_RSHIFT)

return set_error(serror, SCRIPT_ERR_DISABLED_OPCODE); // Disabled opcodes.

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

if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) {

return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS);

}

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

if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) {

return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS);

}

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);

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.back() = !vfExec.back();

}

break;

case OP_ENDIF:

{

if (vfExec.empty())

return set_error(serror, SCRIPT_ERR_UNBALANCED_CONDITIONAL);

vfExec.pop_back();

}

break;

case OP_VERIFY:

{

// (true -- ) or

// (false -- false) and return

if (stack.size() < 1)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

bool fValue = CastToBool(stacktop(-1));

if (fValue)

popstack(stack);

else

return set_error(serror, SCRIPT_ERR_VERIFY);

}

break;

case OP_RETURN:

{

return set_error(serror, SCRIPT_ERR_OP_RETURN);

}

break;

//

// Stack ops

//

case OP_TOALTSTACK:

{

if (stack.size() < 1)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

altstack.push_back(stacktop(-1));

popstack(stack);

}

break;

case OP_FROMALTSTACK:

{

if (altstack.size() < 1)

return set_error(serror, SCRIPT_ERR_INVALID_ALTSTACK_OPERATION);

stack.push_back(altstacktop(-1));

popstack(altstack);

}

break;

case OP_2DROP:

{

// (x1 x2 -- )

if (stack.size() < 2)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

popstack(stack);

popstack(stack);

}

break;

case OP_2DUP:

{

// (x1 x2 -- x1 x2 x1 x2)

if (stack.size() < 2)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype vch1 = stacktop(-2);

valtype vch2 = stacktop(-1);

stack.push_back(vch1);

stack.push_back(vch2);

}

break;

case OP_3DUP:

{

// (x1 x2 x3 -- x1 x2 x3 x1 x2 x3)

if (stack.size() < 3)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype vch1 = stacktop(-3);

valtype vch2 = stacktop(-2);

valtype vch3 = stacktop(-1);

stack.push_back(vch1);

stack.push_back(vch2);

stack.push_back(vch3);

}

break;

case OP_2OVER:

{

// (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2)

if (stack.size() < 4)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype vch1 = stacktop(-4);

valtype vch2 = stacktop(-3);

stack.push_back(vch1);

stack.push_back(vch2);

}

break;

case OP_2ROT:

{

// (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2)

if (stack.size() < 6)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype vch1 = stacktop(-6);

valtype vch2 = stacktop(-5);

stack.erase(stack.end()-6, stack.end()-4);

stack.push_back(vch1);

stack.push_back(vch2);

}

break;

case OP_2SWAP:

{

// (x1 x2 x3 x4 -- x3 x4 x1 x2)

if (stack.size() < 4)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

swap(stacktop(-4), stacktop(-2));

swap(stacktop(-3), stacktop(-1));

}

break;

case OP_IFDUP:

{

// (x - 0 | x x)

if (stack.size() < 1)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype vch = stacktop(-1);

if (CastToBool(vch))

stack.push_back(vch);

}

break;

case OP_DEPTH:

{

// -- stacksize

CScriptNum bn(stack.size());

stack.push_back(bn.getvch());

}

break;

case OP_DROP:

{

// (x -- )

if (stack.size() < 1)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

popstack(stack);

}

break;

case OP_DUP:

{

// (x -- x x)

if (stack.size() < 1)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype vch = stacktop(-1);

stack.push_back(vch);

}

break;

case OP_NIP:

{

// (x1 x2 -- x2)

if (stack.size() < 2)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

stack.erase(stack.end() - 2);

}

break;

case OP_OVER:

{

// (x1 x2 -- x1 x2 x1)

if (stack.size() < 2)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype vch = stacktop(-2);

stack.push_back(vch);

}

break;

case OP_PICK:

case OP_ROLL:

{

// (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn)

// (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)

if (stack.size() < 2)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

int n = CScriptNum(stacktop(-1), fRequireMinimal).getint();

popstack(stack);

if (n < 0 || n >= (int)stack.size())

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype vch = stacktop(-n-1);

if (opcode == OP_ROLL)

stack.erase(stack.end()-n-1);

stack.push_back(vch);

}

break;

case OP_ROT:

{

// (x1 x2 x3 -- x2 x3 x1)

// x2 x1 x3 after first swap

// x2 x3 x1 after second swap

if (stack.size() < 3)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

swap(stacktop(-3), stacktop(-2));

swap(stacktop(-2), stacktop(-1));

}

break;

case OP_SWAP:

{

// (x1 x2 -- x2 x1)

if (stack.size() < 2)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

swap(stacktop(-2), stacktop(-1));

}

break;

case OP_TUCK:

{

// (x1 x2 -- x2 x1 x2)

if (stack.size() < 2)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype vch = stacktop(-1);

stack.insert(stack.end()-2, vch);

}

break;

case OP_SIZE:

{

// (in -- in size)

if (stack.size() < 1)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

CScriptNum bn(stacktop(-1).size());

stack.push_back(bn.getvch());

}

break;

//

// Bitwise logic

//

case OP_EQUAL:

case OP_EQUALVERIFY:

//case OP_NOTEQUAL: // use OP_NUMNOTEQUAL

{

// (x1 x2 - bool)

if (stack.size() < 2)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype& vch1 = stacktop(-2);

valtype& vch2 = stacktop(-1);

bool fEqual = (vch1 == vch2);

// OP_NOTEQUAL is disabled because it would be too easy to say

// something like n != 1 and have some wiseguy pass in 1 with extra

// zero bytes after it (numerically, 0x01 == 0x0001 == 0x000001)

//if (opcode == OP_NOTEQUAL)

// fEqual = !fEqual;

popstack(stack);

popstack(stack);

stack.push_back(fEqual ? vchTrue : vchFalse);

if (opcode == OP_EQUALVERIFY)

{

if (fEqual)

popstack(stack);

else

return set_error(serror, SCRIPT_ERR_EQUALVERIFY);

}

}

break;

//

// Numeric

//

case OP_1ADD:

case OP_1SUB:

case OP_NEGATE:

case OP_ABS:

case OP_NOT:

case OP_0NOTEQUAL:

{

// (in -- out)

if (stack.size() < 1)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

CScriptNum bn(stacktop(-1), fRequireMinimal);

switch (opcode)

{

case OP_1ADD: bn += bnOne; break;

case OP_1SUB: bn -= bnOne; break;

case OP_NEGATE: bn = -bn; break;

case OP_ABS: if (bn < bnZero) bn = -bn; break;

case OP_NOT: bn = (bn == bnZero); break;

case OP_0NOTEQUAL: bn = (bn != bnZero); break;

default: assert(!"invalid opcode"); break;

}

popstack(stack);

stack.push_back(bn.getvch());

}

break;

case OP_ADD:

case OP_SUB:

case OP_BOOLAND:

case OP_BOOLOR:

case OP_NUMEQUAL:

case OP_NUMEQUALVERIFY:

case OP_NUMNOTEQUAL:

case OP_LESSTHAN:

case OP_GREATERTHAN:

case OP_LESSTHANOREQUAL:

case OP_GREATERTHANOREQUAL:

case OP_MIN:

case OP_MAX:

{

// (x1 x2 -- out)

if (stack.size() < 2)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

CScriptNum bn1(stacktop(-2), fRequireMinimal);

CScriptNum bn2(stacktop(-1), fRequireMinimal);

CScriptNum bn(0);

switch (opcode)

{

case OP_ADD:

bn = bn1 + bn2;

break;

case OP_SUB:

bn = bn1 - bn2;

break;

case OP_BOOLAND: bn = (bn1 != bnZero && bn2 != bnZero); break;

case OP_BOOLOR: bn = (bn1 != bnZero || bn2 != bnZero); break;

case OP_NUMEQUAL: bn = (bn1 == bn2); break;

case OP_NUMEQUALVERIFY: bn = (bn1 == bn2); break;

case OP_NUMNOTEQUAL: bn = (bn1 != bn2); break;

case OP_LESSTHAN: bn = (bn1 < bn2); break;

case OP_GREATERTHAN: bn = (bn1 > bn2); break;

case OP_LESSTHANOREQUAL: bn = (bn1 <= bn2); break;

case OP_GREATERTHANOREQUAL: bn = (bn1 >= bn2); break;

case OP_MIN: bn = (bn1 < bn2 ? bn1 : bn2); break;

case OP_MAX: bn = (bn1 > bn2 ? bn1 : bn2); break;

default: assert(!"invalid opcode"); break;

}

popstack(stack);

popstack(stack);

stack.push_back(bn.getvch());

if (opcode == OP_NUMEQUALVERIFY)

{

if (CastToBool(stacktop(-1)))

popstack(stack);

else

return set_error(serror, SCRIPT_ERR_NUMEQUALVERIFY);

}

}

break;

case OP_WITHIN:

{

// (x min max -- out)

if (stack.size() < 3)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

CScriptNum bn1(stacktop(-3), fRequireMinimal);

CScriptNum bn2(stacktop(-2), fRequireMinimal);

CScriptNum bn3(stacktop(-1), fRequireMinimal);

bool fValue = (bn2 <= bn1 && bn1 < bn3);

popstack(stack);

popstack(stack);

popstack(stack);

stack.push_back(fValue ? vchTrue : vchFalse);

}

break;

//

// Crypto

//

case OP_RIPEMD160:

case OP_SHA1:

case OP_SHA256:

case OP_HASH160:

case OP_HASH256:

{

// (in -- hash)

if (stack.size() < 1)

return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);

valtype& vch = stacktop(-1);

valtype vchHash((opcode == OP_RIPEMD160 || opcode == OP_SHA1 || opcode == OP_HASH160) ? 20 : 32);

if (opcode == OP_RIPEMD160)

CRIPEMD160().Write(vch.data(), vch.size()).Finalize(vchHash.data());

else if (opcode == OP_SHA1)

CSHA1().Write(vch.data(), vch.size()).Finalize(vchHash.data());

else if (opcode == OP_SHA256)

CSHA256().Write(vch.data(), vch.size()).Finalize(vchHash.data());

else if (opcode == OP_HASH160)

CHash160().Write(vch.data(), vch.size()).Finalize(vchHash.data());

else if (opcode == OP_HASH256)

CHash256().Write(vch.data(), vch.size()).Finalize(vchHash.data());

popstack(stack);

stack.push_back(vchHash);

}

break;

case OP_CODESEPARATOR:

{

// Hash starts after the code separator

pbegincodehash = pc;

}

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);

// 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) {

scriptCode.FindAndDelete(CScript(vchSig));

}

if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) {

//serror is set

return false;

}

bool fSuccess = checker.CheckSig(vchSig, vchPubKey, scriptCode, sigversion);

if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && vchSig.size())

return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL);

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_CHECKMULTISIG:

case OP_CHECKMULTISIGVERIFY:

{

// ([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) {

scriptCode.FindAndDelete(CScript(vchSig));

}

}

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.CheckSig(vchSig, vchPubKey, scriptCode, sigversion);

if (fOk) {

isig++;

nSigsCount--;

}

ikey++;

nKeysCount--;

// If there are more signatures left than keys left,

// then too many signatures have failed. Exit early,

// without checking any further signatures.

if (nSigsCount > nKeysCount)

fSuccess = false;

}

// Clean up stack of actual arguments

while (i-- > 1) {

// If the operation failed, we require that all signatures must be empty vector

if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && !ikey2 && stacktop(-1).size())

return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL);

if (ikey2 > 0)

ikey2--;

popstack(stack);

}