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bitcore/lib/script/interpreter.js

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'use strict';
var _ = require('lodash');
var Script = require('./script');
var Opcode = require('../opcode');
var BN = require('../crypto/bn');
var Hash = require('../crypto/hash');
var Signature = require('../crypto/signature');
var PublicKey = require('../publickey');
/**
* Bitcoin transactions contain scripts. Each input has a script called the
* scriptSig, and each output has a script called the scriptPubkey. To validate
* an input, the input's script is concatenated with the referenced output script,
* and the result is executed. If at the end of execution the stack contains a
* "true" value, then the transaction is valid.
*
* The primary way to use this class is via the verify function.
* e.g., Interpreter().verify( ... );
*/
var Interpreter = function Interpreter(obj) {
if (!(this instanceof Interpreter)) {
return new Interpreter(obj);
}
if (obj) {
this.initialize();
this.set(obj);
} else {
this.initialize();
}
};
/**
* Verifies a Script by executing it and returns true if it is valid.
* This function needs to be provided with the scriptSig and the scriptPubkey
* separately.
* @param {Script} scriptSig - the script's first part (corresponding to the tx input)
* @param {Script} scriptPubkey - the script's last part (corresponding to the tx output)
* @param {Transaction=} tx - the Transaction containing the scriptSig in one input (used
* to check signature validity for some opcodes like OP_CHECKSIG)
* @param {number} nin - index of the transaction input containing the scriptSig verified.
* @param {number} flags - evaluation flags. See Interpreter.SCRIPT_* constants
*
* Translated from bitcoind's VerifyScript
*/
Interpreter.prototype.verify = function(scriptSig, scriptPubkey, tx, nin, flags) {
var Transaction = require('../transaction');
if (_.isUndefined(tx)) {
tx = new Transaction();
}
if (_.isUndefined(nin)) {
nin = 0;
}
if (_.isUndefined(flags)) {
flags = 0;
}
this.set({
script: scriptSig,
tx: tx,
nin: nin,
flags: flags
});
var stackCopy;
if ((flags & Interpreter.SCRIPT_VERIFY_SIGPUSHONLY) !== 0 && !scriptSig.isPushOnly()) {
this.errstr = 'SCRIPT_ERR_SIG_PUSHONLY';
return false;
}
// evaluate scriptSig
if (!this.evaluate()) {
return false;
}
if (flags & Interpreter.SCRIPT_VERIFY_P2SH) {
stackCopy = this.stack.slice();
}
var stack = this.stack;
this.initialize();
this.set({
script: scriptPubkey,
stack: stack,
tx: tx,
nin: nin,
flags: flags
});
// evaluate scriptPubkey
if (!this.evaluate()) {
return false;
}
if (this.stack.length === 0) {
this.errstr = 'SCRIPT_ERR_EVAL_FALSE_NO_RESULT';
return false;
}
var buf = this.stack[this.stack.length - 1];
if (!Interpreter.castToBool(buf)) {
this.errstr = 'SCRIPT_ERR_EVAL_FALSE_IN_STACK';
return false;
}
// Additional validation for spend-to-script-hash transactions:
if ((flags & Interpreter.SCRIPT_VERIFY_P2SH) && scriptPubkey.isScriptHashOut()) {
// scriptSig must be literals-only or validation fails
if (!scriptSig.isPushOnly()) {
this.errstr = 'SCRIPT_ERR_SIG_PUSHONLY';
return false;
}
// stackCopy 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.
if (stackCopy.length === 0) {
throw new Error('internal error - stack copy empty');
}
var redeemScriptSerialized = stackCopy[stackCopy.length - 1];
var redeemScript = Script.fromBuffer(redeemScriptSerialized);
stackCopy.pop();
this.initialize();
this.set({
script: redeemScript,
stack: stackCopy,
tx: tx,
nin: nin,
flags: flags
});
// evaluate redeemScript
if (!this.evaluate()) {
return false;
}
if (stackCopy.length === 0) {
this.errstr = 'SCRIPT_ERR_EVAL_FALSE_NO_P2SH_STACK';
return false;
}
if (!Interpreter.castToBool(stackCopy[stackCopy.length - 1])) {
this.errstr = 'SCRIPT_ERR_EVAL_FALSE_IN_P2SH_STACK';
return false;
} else {
return true;
}
}
return true;
};
module.exports = Interpreter;
Interpreter.prototype.initialize = function(obj) {
this.stack = [];
this.altstack = [];
this.pc = 0;
this.pbegincodehash = 0;
this.nOpCount = 0;
this.vfExec = [];
this.errstr = '';
this.flags = 0;
};
Interpreter.prototype.set = function(obj) {
this.script = obj.script || this.script;
this.tx = obj.tx || this.tx;
this.nin = typeof obj.nin !== 'undefined' ? obj.nin : this.nin;
this.stack = obj.stack || this.stack;
this.altstack = obj.altack || this.altstack;
this.pc = typeof obj.pc !== 'undefined' ? obj.pc : this.pc;
this.pbegincodehash = typeof obj.pbegincodehash !== 'undefined' ? obj.pbegincodehash : this.pbegincodehash;
this.nOpCount = typeof obj.nOpCount !== 'undefined' ? obj.nOpCount : this.nOpCount;
this.vfExec = obj.vfExec || this.vfExec;
this.errstr = obj.errstr || this.errstr;
this.flags = typeof obj.flags !== 'undefined' ? obj.flags : this.flags;
};
Interpreter.true = new Buffer([1]);
Interpreter.false = new Buffer([]);
Interpreter.MAX_SCRIPT_ELEMENT_SIZE = 520;
Interpreter.LOCKTIME_THRESHOLD = 500000000;
Interpreter.LOCKTIME_THRESHOLD_BN = new BN(Interpreter.LOCKTIME_THRESHOLD);
// flags taken from bitcoind
// bitcoind commit: b5d1b1092998bc95313856d535c632ea5a8f9104
Interpreter.SCRIPT_VERIFY_NONE = 0;
// Evaluate P2SH subscripts (softfork safe, BIP16).
Interpreter.SCRIPT_VERIFY_P2SH = (1 << 0);
// Passing a non-strict-DER signature or one with undefined hashtype to a checksig operation causes script failure.
// Passing a pubkey that is not (0x04 + 64 bytes) or (0x02 or 0x03 + 32 bytes) to checksig causes that pubkey to be
// skipped (not softfork safe: this flag can widen the validity of OP_CHECKSIG OP_NOT).
Interpreter.SCRIPT_VERIFY_STRICTENC = (1 << 1);
// Passing a non-strict-DER signature to a checksig operation causes script failure (softfork safe, BIP62 rule 1)
Interpreter.SCRIPT_VERIFY_DERSIG = (1 << 2);
// Passing a non-strict-DER signature or one with S > order/2 to a checksig operation causes script failure
// (softfork safe, BIP62 rule 5).
Interpreter.SCRIPT_VERIFY_LOW_S = (1 << 3);
// verify dummy stack item consumed by CHECKMULTISIG is of zero-length (softfork safe, BIP62 rule 7).
Interpreter.SCRIPT_VERIFY_NULLDUMMY = (1 << 4);
// Using a non-push operator in the scriptSig causes script failure (softfork safe, BIP62 rule 2).
Interpreter.SCRIPT_VERIFY_SIGPUSHONLY = (1 << 5);
// Require minimal encodings for all push operations (OP_0... OP_16, OP_1NEGATE where possible, direct
// pushes up to 75 bytes, OP_PUSHDATA up to 255 bytes, OP_PUSHDATA2 for anything larger). Evaluating
// any other push causes the script to fail (BIP62 rule 3).
// In addition, whenever a stack element is interpreted as a number, it must be of minimal length (BIP62 rule 4).
// (softfork safe)
Interpreter.SCRIPT_VERIFY_MINIMALDATA = (1 << 6);
// Discourage use of NOPs reserved for upgrades (NOP1-10)
//
// Provided so that nodes can avoid accepting or mining transactions
// containing executed NOP's whose meaning may change after a soft-fork,
// thus rendering the script invalid; with this flag set executing
// discouraged NOPs fails the script. This verification flag will never be
// a mandatory flag applied to scripts in a block. NOPs that are not
// executed, e.g. within an unexecuted IF ENDIF block, are *not* rejected.
Interpreter.SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS = (1 << 7);
// CLTV See BIP65 for details.
Interpreter.SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY = (1 << 9);
Interpreter.castToBool = function(buf) {
for (var i = 0; i < buf.length; i++) {
if (buf[i] !== 0) {
// can be negative zero
if (i === buf.length - 1 && buf[i] === 0x80) {
return false;
}
return true;
}
}
return false;
};
/**
* Translated from bitcoind's CheckSignatureEncoding
*/
Interpreter.prototype.checkSignatureEncoding = function(buf) {
var sig;
if ((this.flags & (Interpreter.SCRIPT_VERIFY_DERSIG | Interpreter.SCRIPT_VERIFY_LOW_S | Interpreter.SCRIPT_VERIFY_STRICTENC)) !== 0 && !Signature.isTxDER(buf)) {
this.errstr = 'SCRIPT_ERR_SIG_DER_INVALID_FORMAT';
return false;
} else if ((this.flags & Interpreter.SCRIPT_VERIFY_LOW_S) !== 0) {
sig = Signature.fromTxFormat(buf);
if (!sig.hasLowS()) {
this.errstr = 'SCRIPT_ERR_SIG_DER_HIGH_S';
return false;
}
} else if ((this.flags & Interpreter.SCRIPT_VERIFY_STRICTENC) !== 0) {
sig = Signature.fromTxFormat(buf);
if (!sig.hasDefinedHashtype()) {
this.errstr = 'SCRIPT_ERR_SIG_HASHTYPE';
return false;
}
}
return true;
};
/**
* Translated from bitcoind's CheckPubKeyEncoding
*/
Interpreter.prototype.checkPubkeyEncoding = function(buf) {
if ((this.flags & Interpreter.SCRIPT_VERIFY_STRICTENC) !== 0 && !PublicKey.isValid(buf)) {
this.errstr = 'SCRIPT_ERR_PUBKEYTYPE';
return false;
}
return true;
};
/**
* Based on bitcoind's EvalScript function, with the inner loop moved to
* Interpreter.prototype.step()
* bitcoind commit: b5d1b1092998bc95313856d535c632ea5a8f9104
*/
Interpreter.prototype.evaluate = function() {
if (this.script.toBuffer().length > 10000) {
this.errstr = 'SCRIPT_ERR_SCRIPT_SIZE';
return false;
}
try {
while (this.pc < this.script.chunks.length) {
var fSuccess = this.step();
if (!fSuccess) {
return false;
}
}
// Size limits
if (this.stack.length + this.altstack.length > 1000) {
this.errstr = 'SCRIPT_ERR_STACK_SIZE';
return false;
}
} catch (e) {
this.errstr = 'SCRIPT_ERR_UNKNOWN_ERROR: ' + e;
return false;
}
if (this.vfExec.length > 0) {
this.errstr = 'SCRIPT_ERR_UNBALANCED_CONDITIONAL';
return false;
}
return true;
};
/**
* Checks a locktime parameter with the transaction's locktime.
* There are two times of nLockTime: lock-by-blockheight and lock-by-blocktime,
* distinguished by whether nLockTime < LOCKTIME_THRESHOLD = 500000000
*
* See the corresponding code on bitcoin core:
* https://github.com/bitcoin/bitcoin/blob/ffd75adce01a78b3461b3ff05bcc2b530a9ce994/src/script/interpreter.cpp#L1129
*
* @param {BN} nLockTime the locktime read from the script
* @return {boolean} true if the transaction's locktime is less than or equal to
* the transaction's locktime
*/
Interpreter.prototype.checkLockTime = function(nLockTime) {
// 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 (!(
(this.tx.nLockTime < Interpreter.LOCKTIME_THRESHOLD && nLockTime.lt(Interpreter.LOCKTIME_THRESHOLD_BN)) ||
(this.tx.nLockTime >= Interpreter.LOCKTIME_THRESHOLD && nLockTime.gte(Interpreter.LOCKTIME_THRESHOLD_BN))
)) {
return false;
}
// Now that we know we're comparing apples-to-apples, the
// comparison is a simple numeric one.
if (nLockTime.gt(new BN(this.tx.nLockTime))) {
return false;
}
// Finally the nLockTime feature can be disabled and thus
// CHECKLOCKTIMEVERIFY bypassed if every txin has been
// finalized by setting nSequence to maxint. The
// transaction would be allowed into the blockchain, making
// the opcode ineffective.
//
// Testing if this vin is not final is sufficient to
// prevent this condition. Alternatively we could test all
// inputs, but testing just this input minimizes the data
// required to prove correct CHECKLOCKTIMEVERIFY execution.
if (!this.tx.inputs[this.nin].isFinal()) {
return false;
}
return true;
}
/**
* Based on the inner loop of bitcoind's EvalScript function
* bitcoind commit: b5d1b1092998bc95313856d535c632ea5a8f9104
*/
Interpreter.prototype.step = function() {
var fRequireMinimal = (this.flags & Interpreter.SCRIPT_VERIFY_MINIMALDATA) !== 0;
//bool fExec = !count(vfExec.begin(), vfExec.end(), false);
var fExec = (this.vfExec.indexOf(false) === -1);
var buf, buf1, buf2, spliced, n, x1, x2, bn, bn1, bn2, bufSig, bufPubkey, subscript;
var sig, pubkey;
var fValue, fSuccess;
// Read instruction
var chunk = this.script.chunks[this.pc];
this.pc++;
var opcodenum = chunk.opcodenum;
if (_.isUndefined(opcodenum)) {
this.errstr = 'SCRIPT_ERR_UNDEFINED_OPCODE';
return false;
}
if (chunk.buf && chunk.buf.length > Interpreter.MAX_SCRIPT_ELEMENT_SIZE) {
this.errstr = 'SCRIPT_ERR_PUSH_SIZE';
return false;
}
// Note how Opcode.OP_RESERVED does not count towards the opcode limit.
if (opcodenum > Opcode.OP_16 && ++(this.nOpCount) > 201) {
this.errstr = 'SCRIPT_ERR_OP_COUNT';
return false;
}
if (opcodenum === Opcode.OP_CAT ||
opcodenum === Opcode.OP_SUBSTR ||
opcodenum === Opcode.OP_LEFT ||
opcodenum === Opcode.OP_RIGHT ||
opcodenum === Opcode.OP_INVERT ||
opcodenum === Opcode.OP_AND ||
opcodenum === Opcode.OP_OR ||
opcodenum === Opcode.OP_XOR ||
opcodenum === Opcode.OP_2MUL ||
opcodenum === Opcode.OP_2DIV ||
opcodenum === Opcode.OP_MUL ||
opcodenum === Opcode.OP_DIV ||
opcodenum === Opcode.OP_MOD ||
opcodenum === Opcode.OP_LSHIFT ||
opcodenum === Opcode.OP_RSHIFT) {
this.errstr = 'SCRIPT_ERR_DISABLED_OPCODE';
return false;
}
if (fExec && 0 <= opcodenum && opcodenum <= Opcode.OP_PUSHDATA4) {
if (fRequireMinimal && !this.script.checkMinimalPush(this.pc - 1)) {
this.errstr = 'SCRIPT_ERR_MINIMALDATA';
return false;
}
if (!chunk.buf) {
this.stack.push(Interpreter.false);
} else if (chunk.len !== chunk.buf.length) {
throw new Error('Length of push value not equal to length of data');
} else {
this.stack.push(chunk.buf);
}
} else if (fExec || (Opcode.OP_IF <= opcodenum && opcodenum <= Opcode.OP_ENDIF)) {
switch (opcodenum) {
// Push value
case Opcode.OP_1NEGATE:
case Opcode.OP_1:
case Opcode.OP_2:
case Opcode.OP_3:
case Opcode.OP_4:
case Opcode.OP_5:
case Opcode.OP_6:
case Opcode.OP_7:
case Opcode.OP_8:
case Opcode.OP_9:
case Opcode.OP_10:
case Opcode.OP_11:
case Opcode.OP_12:
case Opcode.OP_13:
case Opcode.OP_14:
case Opcode.OP_15:
case Opcode.OP_16:
{
// ( -- value)
// ScriptNum bn((int)opcode - (int)(Opcode.OP_1 - 1));
n = opcodenum - (Opcode.OP_1 - 1);
buf = new BN(n).toScriptNumBuffer();
this.stack.push(buf);
// 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 Opcode.OP_NOP:
break;
case Opcode.OP_NOP2:
case Opcode.OP_CHECKLOCKTIMEVERIFY:
if (!(this.flags & Interpreter.SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY)) {
// not enabled; treat as a NOP2
if (this.flags & Interpreter.SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) {
this.errstr = 'SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS';
return false;
}
break;
}
if (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
// 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.
var nLockTime = BN.fromScriptNumBuffer(this.stack[this.stack.length - 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.lt(new BN(0))) {
this.errstr = 'SCRIPT_ERR_NEGATIVE_LOCKTIME';
return false;
}
// Actually compare the specified lock time with the transaction.
if (!this.checkLockTime(nLockTime)) {
this.errstr = 'SCRIPT_ERR_UNSATISFIED_LOCKTIME';
return false;
}
break;
case Opcode.OP_NOP1:
case Opcode.OP_NOP3:
case Opcode.OP_NOP4:
case Opcode.OP_NOP5:
case Opcode.OP_NOP6:
case Opcode.OP_NOP7:
case Opcode.OP_NOP8:
case Opcode.OP_NOP9:
case Opcode.OP_NOP10:
{
if (this.flags & Interpreter.SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) {
this.errstr = 'SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS';
return false;
}
}
break;
case Opcode.OP_IF:
case Opcode.OP_NOTIF:
{
// <expression> if [statements] [else [statements]] endif
// bool fValue = false;
fValue = false;
if (fExec) {
if (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_UNBALANCED_CONDITIONAL';
return false;
}
buf = this.stack.pop();
fValue = Interpreter.castToBool(buf);
if (opcodenum === Opcode.OP_NOTIF) {
fValue = !fValue;
}
}
this.vfExec.push(fValue);
}
break;
case Opcode.OP_ELSE:
{
if (this.vfExec.length === 0) {
this.errstr = 'SCRIPT_ERR_UNBALANCED_CONDITIONAL';
return false;
}
this.vfExec[this.vfExec.length - 1] = !this.vfExec[this.vfExec.length - 1];
}
break;
case Opcode.OP_ENDIF:
{
if (this.vfExec.length === 0) {
this.errstr = 'SCRIPT_ERR_UNBALANCED_CONDITIONAL';
return false;
}
this.vfExec.pop();
}
break;
case Opcode.OP_VERIFY:
{
// (true -- ) or
// (false -- false) and return
if (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
buf = this.stack[this.stack.length - 1];
fValue = Interpreter.castToBool(buf);
if (fValue) {
this.stack.pop();
} else {
this.errstr = 'SCRIPT_ERR_VERIFY';
return false;
}
}
break;
case Opcode.OP_RETURN:
{
this.errstr = 'SCRIPT_ERR_OP_RETURN';
return false;
}
break;
//
// Stack ops
//
case Opcode.OP_TOALTSTACK:
{
if (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
this.altstack.push(this.stack.pop());
}
break;
case Opcode.OP_FROMALTSTACK:
{
if (this.altstack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_ALTSTACK_OPERATION';
return false;
}
this.stack.push(this.altstack.pop());
}
break;
case Opcode.OP_2DROP:
{
// (x1 x2 -- )
if (this.stack.length < 2) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
this.stack.pop();
this.stack.pop();
}
break;
case Opcode.OP_2DUP:
{
// (x1 x2 -- x1 x2 x1 x2)
if (this.stack.length < 2) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
buf1 = this.stack[this.stack.length - 2];
buf2 = this.stack[this.stack.length - 1];
this.stack.push(buf1);
this.stack.push(buf2);
}
break;
case Opcode.OP_3DUP:
{
// (x1 x2 x3 -- x1 x2 x3 x1 x2 x3)
if (this.stack.length < 3) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
buf1 = this.stack[this.stack.length - 3];
buf2 = this.stack[this.stack.length - 2];
var buf3 = this.stack[this.stack.length - 1];
this.stack.push(buf1);
this.stack.push(buf2);
this.stack.push(buf3);
}
break;
case Opcode.OP_2OVER:
{
// (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2)
if (this.stack.length < 4) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
buf1 = this.stack[this.stack.length - 4];
buf2 = this.stack[this.stack.length - 3];
this.stack.push(buf1);
this.stack.push(buf2);
}
break;
case Opcode.OP_2ROT:
{
// (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2)
if (this.stack.length < 6) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
spliced = this.stack.splice(this.stack.length - 6, 2);
this.stack.push(spliced[0]);
this.stack.push(spliced[1]);
}
break;
case Opcode.OP_2SWAP:
{
// (x1 x2 x3 x4 -- x3 x4 x1 x2)
if (this.stack.length < 4) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
spliced = this.stack.splice(this.stack.length - 4, 2);
this.stack.push(spliced[0]);
this.stack.push(spliced[1]);
}
break;
case Opcode.OP_IFDUP:
{
// (x - 0 | x x)
if (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
buf = this.stack[this.stack.length - 1];
fValue = Interpreter.castToBool(buf);
if (fValue) {
this.stack.push(buf);
}
}
break;
case Opcode.OP_DEPTH:
{
// -- stacksize
buf = new BN(this.stack.length).toScriptNumBuffer();
this.stack.push(buf);
}
break;
case Opcode.OP_DROP:
{
// (x -- )
if (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
this.stack.pop();
}
break;
case Opcode.OP_DUP:
{
// (x -- x x)
if (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
this.stack.push(this.stack[this.stack.length - 1]);
}
break;
case Opcode.OP_NIP:
{
// (x1 x2 -- x2)
if (this.stack.length < 2) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
this.stack.splice(this.stack.length - 2, 1);
}
break;
case Opcode.OP_OVER:
{
// (x1 x2 -- x1 x2 x1)
if (this.stack.length < 2) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
this.stack.push(this.stack[this.stack.length - 2]);
}
break;
case Opcode.OP_PICK:
case Opcode.OP_ROLL:
{
// (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn)
// (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)
if (this.stack.length < 2) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
buf = this.stack[this.stack.length - 1];
bn = BN.fromScriptNumBuffer(buf, fRequireMinimal);
n = bn.toNumber();
this.stack.pop();
if (n < 0 || n >= this.stack.length) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
buf = this.stack[this.stack.length - n - 1];
if (opcodenum === Opcode.OP_ROLL) {
this.stack.splice(this.stack.length - n - 1, 1);
}
this.stack.push(buf);
}
break;
case Opcode.OP_ROT:
{
// (x1 x2 x3 -- x2 x3 x1)
// x2 x1 x3 after first swap
// x2 x3 x1 after second swap
if (this.stack.length < 3) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
x1 = this.stack[this.stack.length - 3];
x2 = this.stack[this.stack.length - 2];
var x3 = this.stack[this.stack.length - 1];
this.stack[this.stack.length - 3] = x2;
this.stack[this.stack.length - 2] = x3;
this.stack[this.stack.length - 1] = x1;
}
break;
case Opcode.OP_SWAP:
{
// (x1 x2 -- x2 x1)
if (this.stack.length < 2) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
x1 = this.stack[this.stack.length - 2];
x2 = this.stack[this.stack.length - 1];
this.stack[this.stack.length - 2] = x2;
this.stack[this.stack.length - 1] = x1;
}
break;
case Opcode.OP_TUCK:
{
// (x1 x2 -- x2 x1 x2)
if (this.stack.length < 2) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
this.stack.splice(this.stack.length - 2, 0, this.stack[this.stack.length - 1]);
}
break;
case Opcode.OP_SIZE:
{
// (in -- in size)
if (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
bn = new BN(this.stack[this.stack.length - 1].length);
this.stack.push(bn.toScriptNumBuffer());
}
break;
//
// Bitwise logic
//
case Opcode.OP_EQUAL:
case Opcode.OP_EQUALVERIFY:
//case Opcode.OP_NOTEQUAL: // use Opcode.OP_NUMNOTEQUAL
{
// (x1 x2 - bool)
if (this.stack.length < 2) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
buf1 = this.stack[this.stack.length - 2];
buf2 = this.stack[this.stack.length - 1];
var fEqual = buf1.toString('hex') === buf2.toString('hex');
this.stack.pop();
this.stack.pop();
this.stack.push(fEqual ? Interpreter.true : Interpreter.false);
if (opcodenum === Opcode.OP_EQUALVERIFY) {
if (fEqual) {
this.stack.pop();
} else {
this.errstr = 'SCRIPT_ERR_EQUALVERIFY';
return false;
}
}
}
break;
//
// Numeric
//
case Opcode.OP_1ADD:
case Opcode.OP_1SUB:
case Opcode.OP_NEGATE:
case Opcode.OP_ABS:
case Opcode.OP_NOT:
case Opcode.OP_0NOTEQUAL:
{
// (in -- out)
if (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
buf = this.stack[this.stack.length - 1];
bn = BN.fromScriptNumBuffer(buf, fRequireMinimal);
switch (opcodenum) {
case Opcode.OP_1ADD:
bn = bn.add(BN.One);
break;
case Opcode.OP_1SUB:
bn = bn.sub(BN.One);
break;
case Opcode.OP_NEGATE:
bn = bn.neg();
break;
case Opcode.OP_ABS:
if (bn.cmp(BN.Zero) < 0) {
bn = bn.neg();
}
break;
case Opcode.OP_NOT:
bn = new BN((bn.cmp(BN.Zero) === 0) + 0);
break;
case Opcode.OP_0NOTEQUAL:
bn = new BN((bn.cmp(BN.Zero) !== 0) + 0);
break;
//default: assert(!'invalid opcode'); break; // TODO: does this ever occur?
}
this.stack.pop();
this.stack.push(bn.toScriptNumBuffer());
}
break;
case Opcode.OP_ADD:
case Opcode.OP_SUB:
case Opcode.OP_BOOLAND:
case Opcode.OP_BOOLOR:
case Opcode.OP_NUMEQUAL:
case Opcode.OP_NUMEQUALVERIFY:
case Opcode.OP_NUMNOTEQUAL:
case Opcode.OP_LESSTHAN:
case Opcode.OP_GREATERTHAN:
case Opcode.OP_LESSTHANOREQUAL:
case Opcode.OP_GREATERTHANOREQUAL:
case Opcode.OP_MIN:
case Opcode.OP_MAX:
{
// (x1 x2 -- out)
if (this.stack.length < 2) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
bn1 = BN.fromScriptNumBuffer(this.stack[this.stack.length - 2], fRequireMinimal);
bn2 = BN.fromScriptNumBuffer(this.stack[this.stack.length - 1], fRequireMinimal);
bn = new BN(0);
switch (opcodenum) {
case Opcode.OP_ADD:
bn = bn1.add(bn2);
break;
case Opcode.OP_SUB:
bn = bn1.sub(bn2);
break;
// case Opcode.OP_BOOLAND: bn = (bn1 != bnZero && bn2 != bnZero); break;
case Opcode.OP_BOOLAND:
bn = new BN(((bn1.cmp(BN.Zero) !== 0) && (bn2.cmp(BN.Zero) !== 0)) + 0);
break;
// case Opcode.OP_BOOLOR: bn = (bn1 != bnZero || bn2 != bnZero); break;
case Opcode.OP_BOOLOR:
bn = new BN(((bn1.cmp(BN.Zero) !== 0) || (bn2.cmp(BN.Zero) !== 0)) + 0);
break;
// case Opcode.OP_NUMEQUAL: bn = (bn1 == bn2); break;
case Opcode.OP_NUMEQUAL:
bn = new BN((bn1.cmp(bn2) === 0) + 0);
break;
// case Opcode.OP_NUMEQUALVERIFY: bn = (bn1 == bn2); break;
case Opcode.OP_NUMEQUALVERIFY:
bn = new BN((bn1.cmp(bn2) === 0) + 0);
break;
// case Opcode.OP_NUMNOTEQUAL: bn = (bn1 != bn2); break;
case Opcode.OP_NUMNOTEQUAL:
bn = new BN((bn1.cmp(bn2) !== 0) + 0);
break;
// case Opcode.OP_LESSTHAN: bn = (bn1 < bn2); break;
case Opcode.OP_LESSTHAN:
bn = new BN((bn1.cmp(bn2) < 0) + 0);
break;
// case Opcode.OP_GREATERTHAN: bn = (bn1 > bn2); break;
case Opcode.OP_GREATERTHAN:
bn = new BN((bn1.cmp(bn2) > 0) + 0);
break;
// case Opcode.OP_LESSTHANOREQUAL: bn = (bn1 <= bn2); break;
case Opcode.OP_LESSTHANOREQUAL:
bn = new BN((bn1.cmp(bn2) <= 0) + 0);
break;
// case Opcode.OP_GREATERTHANOREQUAL: bn = (bn1 >= bn2); break;
case Opcode.OP_GREATERTHANOREQUAL:
bn = new BN((bn1.cmp(bn2) >= 0) + 0);
break;
case Opcode.OP_MIN:
bn = (bn1.cmp(bn2) < 0 ? bn1 : bn2);
break;
case Opcode.OP_MAX:
bn = (bn1.cmp(bn2) > 0 ? bn1 : bn2);
break;
// default: assert(!'invalid opcode'); break; //TODO: does this ever occur?
}
this.stack.pop();
this.stack.pop();
this.stack.push(bn.toScriptNumBuffer());
if (opcodenum === Opcode.OP_NUMEQUALVERIFY) {
// if (CastToBool(stacktop(-1)))
if (Interpreter.castToBool(this.stack[this.stack.length - 1])) {
this.stack.pop();
} else {
this.errstr = 'SCRIPT_ERR_NUMEQUALVERIFY';
return false;
}
}
}
break;
case Opcode.OP_WITHIN:
{
// (x min max -- out)
if (this.stack.length < 3) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
bn1 = BN.fromScriptNumBuffer(this.stack[this.stack.length - 3], fRequireMinimal);
bn2 = BN.fromScriptNumBuffer(this.stack[this.stack.length - 2], fRequireMinimal);
var bn3 = BN.fromScriptNumBuffer(this.stack[this.stack.length - 1], fRequireMinimal);
//bool fValue = (bn2 <= bn1 && bn1 < bn3);
fValue = (bn2.cmp(bn1) <= 0) && (bn1.cmp(bn3) < 0);
this.stack.pop();
this.stack.pop();
this.stack.pop();
this.stack.push(fValue ? Interpreter.true : Interpreter.false);
}
break;
//
// Crypto
//
case Opcode.OP_RIPEMD160:
case Opcode.OP_SHA1:
case Opcode.OP_SHA256:
case Opcode.OP_HASH160:
case Opcode.OP_HASH256:
{
// (in -- hash)
if (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
buf = this.stack[this.stack.length - 1];
//valtype vchHash((opcode == Opcode.OP_RIPEMD160 ||
// opcode == Opcode.OP_SHA1 || opcode == Opcode.OP_HASH160) ? 20 : 32);
var bufHash;
if (opcodenum === Opcode.OP_RIPEMD160) {
bufHash = Hash.ripemd160(buf);
} else if (opcodenum === Opcode.OP_SHA1) {
bufHash = Hash.sha1(buf);
} else if (opcodenum === Opcode.OP_SHA256) {
bufHash = Hash.sha256(buf);
} else if (opcodenum === Opcode.OP_HASH160) {
bufHash = Hash.sha256ripemd160(buf);
} else if (opcodenum === Opcode.OP_HASH256) {
bufHash = Hash.sha256sha256(buf);
}
this.stack.pop();
this.stack.push(bufHash);
}
break;
case Opcode.OP_CODESEPARATOR:
{
// Hash starts after the code separator
this.pbegincodehash = this.pc;
}
break;
case Opcode.OP_CHECKSIG:
case Opcode.OP_CHECKSIGVERIFY:
{
// (sig pubkey -- bool)
if (this.stack.length < 2) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
bufSig = this.stack[this.stack.length - 2];
bufPubkey = this.stack[this.stack.length - 1];
// Subset of script starting at the most recent codeseparator
// CScript scriptCode(pbegincodehash, pend);
subscript = new Script().set({
chunks: this.script.chunks.slice(this.pbegincodehash)
});
// Drop the signature, since there's no way for a signature to sign itself
var tmpScript = new Script().add(bufSig);
subscript.findAndDelete(tmpScript);
if (!this.checkSignatureEncoding(bufSig) || !this.checkPubkeyEncoding(bufPubkey)) {
return false;
}
try {
sig = Signature.fromTxFormat(bufSig);
pubkey = PublicKey.fromBuffer(bufPubkey, false);
fSuccess = this.tx.verifySignature(sig, pubkey, this.nin, subscript);
} catch (e) {
//invalid sig or pubkey
fSuccess = false;
}
this.stack.pop();
this.stack.pop();
// stack.push_back(fSuccess ? vchTrue : vchFalse);
this.stack.push(fSuccess ? Interpreter.true : Interpreter.false);
if (opcodenum === Opcode.OP_CHECKSIGVERIFY) {
if (fSuccess) {
this.stack.pop();
} else {
this.errstr = 'SCRIPT_ERR_CHECKSIGVERIFY';
return false;
}
}
}
break;
case Opcode.OP_CHECKMULTISIG:
case Opcode.OP_CHECKMULTISIGVERIFY:
{
// ([sig ...] num_of_signatures [pubkey ...] num_of_pubkeys -- bool)
var i = 1;
if (this.stack.length < i) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
var nKeysCount = BN.fromScriptNumBuffer(this.stack[this.stack.length - i], fRequireMinimal).toNumber();
if (nKeysCount < 0 || nKeysCount > 20) {
this.errstr = 'SCRIPT_ERR_PUBKEY_COUNT';
return false;
}
this.nOpCount += nKeysCount;
if (this.nOpCount > 201) {
this.errstr = 'SCRIPT_ERR_OP_COUNT';
return false;
}
// int ikey = ++i;
var ikey = ++i;
i += nKeysCount;
if (this.stack.length < i) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
var nSigsCount = BN.fromScriptNumBuffer(this.stack[this.stack.length - i], fRequireMinimal).toNumber();
if (nSigsCount < 0 || nSigsCount > nKeysCount) {
this.errstr = 'SCRIPT_ERR_SIG_COUNT';
return false;
}
// int isig = ++i;
var isig = ++i;
i += nSigsCount;
if (this.stack.length < i) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
// Subset of script starting at the most recent codeseparator
subscript = new Script().set({
chunks: this.script.chunks.slice(this.pbegincodehash)
});
// Drop the signatures, since there's no way for a signature to sign itself
for (var k = 0; k < nSigsCount; k++) {
bufSig = this.stack[this.stack.length - isig - k];
subscript.findAndDelete(new Script().add(bufSig));
}
fSuccess = true;
while (fSuccess && nSigsCount > 0) {
// valtype& vchSig = stacktop(-isig);
bufSig = this.stack[this.stack.length - isig];
// valtype& vchPubKey = stacktop(-ikey);
bufPubkey = this.stack[this.stack.length - ikey];
if (!this.checkSignatureEncoding(bufSig) || !this.checkPubkeyEncoding(bufPubkey)) {
return false;
}
var fOk;
try {
sig = Signature.fromTxFormat(bufSig);
pubkey = PublicKey.fromBuffer(bufPubkey, false);
fOk = this.tx.verifySignature(sig, pubkey, this.nin, subscript);
} catch (e) {
//invalid sig or pubkey
fOk = false;
}
if (fOk) {
isig++;
nSigsCount--;
}
ikey++;
nKeysCount--;
// If there are more signatures left than keys left,
// then too many signatures have failed
if (nSigsCount > nKeysCount) {
fSuccess = false;
}
}
// Clean up stack of actual arguments
while (i-- > 1) {
this.stack.pop();
}
// 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 (this.stack.length < 1) {
this.errstr = 'SCRIPT_ERR_INVALID_STACK_OPERATION';
return false;
}
if ((this.flags & Interpreter.SCRIPT_VERIFY_NULLDUMMY) && this.stack[this.stack.length - 1].length) {
this.errstr = 'SCRIPT_ERR_SIG_NULLDUMMY';
return false;
}
this.stack.pop();
this.stack.push(fSuccess ? Interpreter.true : Interpreter.false);
if (opcodenum === Opcode.OP_CHECKMULTISIGVERIFY) {
if (fSuccess) {
this.stack.pop();
} else {
this.errstr = 'SCRIPT_ERR_CHECKMULTISIGVERIFY';
return false;
}
}
}
break;
default:
this.errstr = 'SCRIPT_ERR_BAD_OPCODE';
return false;
}
}
return true;
};
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