/**
* Copyright 2011 Google Inc.
* Copyright 2012 Matt Corallo.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.feathercoin.core;
import org.spongycastle.crypto.digests.RIPEMD160Digest;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.*;
import static com.google.feathercoin.core.Utils.bytesToHexString;
/**
* A chunk in a script
*/
class ScriptChunk {
public boolean isOpCode;
public byte[] data;
public int startLocationInProgram;
public ScriptChunk(boolean isOpCode, byte[] data, int startLocationInProgram) {
this.isOpCode = isOpCode;
this.data = data;
this.startLocationInProgram = startLocationInProgram;
}
public boolean equalsOpCode(int opCode) {
return isOpCode &&
data.length == 1 &&
(0xFF & data[0]) == opCode;
}
}
/**
* <p>Programs embedded inside transactions that control redemption of payments.</p>
*
* <p>Feathercoin transactions don't specify what they do directly. Instead <a href="https://en.feathercoin.it/wiki/Script">a
* small binary stack language</a> is used to define programs that when evaluated return whether the transaction
* "accepts" or rejects the other transactions connected to it.</p>
*
* <p>In SPV mode, scripts are not run, because that would require all transactions to be available and lightweight
* clients don't have that data. In full mode, this class is used to run the interpreted language. It also has
* static methods for building scripts.</p>
*/
public class Script {
// Some constants used for decoding the scripts, copied from the reference client
// push value
public static final int OP_0 = 0x00;
public static final int OP_FALSE = OP_0;
public static final int OP_PUSHDATA1 = 0x4c;
public static final int OP_PUSHDATA2 = 0x4d;
public static final int OP_PUSHDATA4 = 0x4e;
public static final int OP_1NEGATE = 0x4f;
public static final int OP_RESERVED = 0x50;
public static final int OP_1 = 0x51;
public static final int OP_TRUE=OP_1;
public static final int OP_2 = 0x52;
public static final int OP_3 = 0x53;
public static final int OP_4 = 0x54;
public static final int OP_5 = 0x55;
public static final int OP_6 = 0x56;
public static final int OP_7 = 0x57;
public static final int OP_8 = 0x58;
public static final int OP_9 = 0x59;
public static final int OP_10 = 0x5a;
public static final int OP_11 = 0x5b;
public static final int OP_12 = 0x5c;
public static final int OP_13 = 0x5d;
public static final int OP_14 = 0x5e;
public static final int OP_15 = 0x5f;
public static final int OP_16 = 0x60;
// control
public static final int OP_NOP = 0x61;
public static final int OP_VER = 0x62;
public static final int OP_IF = 0x63;
public static final int OP_NOTIF = 0x64;
public static final int OP_VERIF = 0x65;
public static final int OP_VERNOTIF = 0x66;
public static final int OP_ELSE = 0x67;
public static final int OP_ENDIF = 0x68;
public static final int OP_VERIFY = 0x69;
public static final int OP_RETURN = 0x6a;
// stack ops
public static final int OP_TOALTSTACK = 0x6b;
public static final int OP_FROMALTSTACK = 0x6c;
public static final int OP_2DROP = 0x6d;
public static final int OP_2DUP = 0x6e;
public static final int OP_3DUP = 0x6f;
public static final int OP_2OVER = 0x70;
public static final int OP_2ROT = 0x71;
public static final int OP_2SWAP = 0x72;
public static final int OP_IFDUP = 0x73;
public static final int OP_DEPTH = 0x74;
public static final int OP_DROP = 0x75;
public static final int OP_DUP = 0x76;
public static final int OP_NIP = 0x77;
public static final int OP_OVER = 0x78;
public static final int OP_PICK = 0x79;
public static final int OP_ROLL = 0x7a;
public static final int OP_ROT = 0x7b;
public static final int OP_SWAP = 0x7c;
public static final int OP_TUCK = 0x7d;
// splice ops
public static final int OP_CAT = 0x7e;
public static final int OP_SUBSTR = 0x7f;
public static final int OP_LEFT = 0x80;
public static final int OP_RIGHT = 0x81;
public static final int OP_SIZE = 0x82;
// bit logic
public static final int OP_INVERT = 0x83;
public static final int OP_AND = 0x84;
public static final int OP_OR = 0x85;
public static final int OP_XOR = 0x86;
public static final int OP_EQUAL = 0x87;
public static final int OP_EQUALVERIFY = 0x88;
public static final int OP_RESERVED1 = 0x89;
public static final int OP_RESERVED2 = 0x8a;
// numeric
public static final int OP_1ADD = 0x8b;
public static final int OP_1SUB = 0x8c;
public static final int OP_2MUL = 0x8d;
public static final int OP_2DIV = 0x8e;
public static final int OP_NEGATE = 0x8f;
public static final int OP_ABS = 0x90;
public static final int OP_NOT = 0x91;
public static final int OP_0NOTEQUAL = 0x92;
public static final int OP_ADD = 0x93;
public static final int OP_SUB = 0x94;
public static final int OP_MUL = 0x95;
public static final int OP_DIV = 0x96;
public static final int OP_MOD = 0x97;
public static final int OP_LSHIFT = 0x98;
public static final int OP_RSHIFT = 0x99;
public static final int OP_BOOLAND = 0x9a;
public static final int OP_BOOLOR = 0x9b;
public static final int OP_NUMEQUAL = 0x9c;
public static final int OP_NUMEQUALVERIFY = 0x9d;
public static final int OP_NUMNOTEQUAL = 0x9e;
public static final int OP_LESSTHAN = 0x9f;
public static final int OP_GREATERTHAN = 0xa0;
public static final int OP_LESSTHANOREQUAL = 0xa1;
public static final int OP_GREATERTHANOREQUAL = 0xa2;
public static final int OP_MIN = 0xa3;
public static final int OP_MAX = 0xa4;
public static final int OP_WITHIN = 0xa5;
// crypto
public static final int OP_RIPEMD160 = 0xa6;
public static final int OP_SHA1 = 0xa7;
public static final int OP_SHA256 = 0xa8;
public static final int OP_HASH160 = 0xa9;
public static final int OP_HASH256 = 0xaa;
public static final int OP_CODESEPARATOR = 0xab;
public static final int OP_CHECKSIG = 0xac;
public static final int OP_CHECKSIGVERIFY = 0xad;
public static final int OP_CHECKMULTISIG = 0xae;
public static final int OP_CHECKMULTISIGVERIFY = 0xaf;
// expansion
public static final int OP_NOP1 = 0xb0;
public static final int OP_NOP2 = 0xb1;
public static final int OP_NOP3 = 0xb2;
public static final int OP_NOP4 = 0xb3;
public static final int OP_NOP5 = 0xb4;
public static final int OP_NOP6 = 0xb5;
public static final int OP_NOP7 = 0xb6;
public static final int OP_NOP8 = 0xb7;
public static final int OP_NOP9 = 0xb8;
public static final int OP_NOP10 = 0xb9;
public static final int OP_INVALIDOPCODE = 0xff;
byte[] program;
private int cursor;
// The program is a set of byte[]s where each element is either [opcode] or [data, data, data ...]
List<ScriptChunk> chunks;
private final NetworkParameters params;
// Only for internal use
private Script() {
params = null;
}
/**
* Construct a Script using the given network parameters and a range of the programBytes array.
*
* @param params Network parameters.
* @param programBytes Array of program bytes from a transaction.
* @param offset How many bytes into programBytes to start reading from.
* @param length How many bytes to read.
* @throws ScriptException
*/
public Script(NetworkParameters params, byte[] programBytes, int offset, int length) throws ScriptException {
this.params = params;
parse(programBytes, offset, length);
}
/**
* Returns the program opcodes as a string, for example "[1234] DUP HAHS160"
*/
public String toString() {
StringBuffer buf = new StringBuffer();
for (ScriptChunk chunk : chunks) {
if (chunk.isOpCode) {
buf.append(getOpCodeName(chunk.data[0]));
buf.append(" ");
} else {
// Data chunk
buf.append("[");
buf.append(bytesToHexString(chunk.data));
buf.append("] ");
}
}
return buf.toString();
}
/**
* Converts the given OpCode into a string (eg "0", "PUSHDATA", or "NON_OP(10)")
*/
public static String getOpCodeName(byte opCode) {
int opcode = opCode & 0xff;
switch (opcode) {
case OP_0:
return "0";
case OP_PUSHDATA1:
return "PUSHDATA1";
case OP_PUSHDATA2:
return "PUSHDATA1";
case OP_PUSHDATA4:
return "PUSHDATA4";
case OP_1NEGATE:
return "1NEGATE";
case OP_RESERVED:
return "RESERVED";
case OP_1:
return "1";
case OP_2:
return "2";
case OP_3:
return "3";
case OP_4:
return "4";
case OP_5:
return "5";
case OP_6:
return "6";
case OP_7:
return "7";
case OP_8:
return "8";
case OP_9:
return "9";
case OP_10:
return "10";
case OP_11:
return "11";
case OP_12:
return "12";
case OP_13:
return "13";
case OP_14:
return "14";
case OP_15:
return "15";
case OP_16:
return "16";
case OP_NOP:
return "NOP";
case OP_VER:
return "VER";
case OP_IF:
return "IF";
case OP_NOTIF:
return "NOTIF";
case OP_VERIF:
return "VERIF";
case OP_VERNOTIF:
return "VERNOTIF";
case OP_ELSE:
return "ELSE";
case OP_ENDIF:
return "ENDIF";
case OP_VERIFY:
return "VERIFY";
case OP_RETURN:
return "RETURN";
case OP_TOALTSTACK:
return "TOALTSTACK";
case OP_FROMALTSTACK:
return "FROMALTSTACK";
case OP_2DROP:
return "2DROP";
case OP_2DUP:
return "2DUP";
case OP_3DUP:
return "3DUP";
case OP_2OVER:
return "2OVER";
case OP_2ROT:
return "2ROT";
case OP_2SWAP:
return "2SWAP";
case OP_IFDUP:
return "IFDUP";
case OP_DEPTH:
return "DEPTH";
case OP_DROP:
return "DROP";
case OP_DUP:
return "DUP";
case OP_NIP:
return "NIP";
case OP_OVER:
return "OVER";
case OP_PICK:
return "PICK";
case OP_ROLL:
return "ROLL";
case OP_ROT:
return "ROT";
case OP_SWAP:
return "SWAP";
case OP_TUCK:
return "TUCK";
case OP_CAT:
return "CAT";
case OP_SUBSTR:
return "SUBSTR";
case OP_LEFT:
return "LEFT";
case OP_RIGHT:
return "RIGHT";
case OP_SIZE:
return "SIZE";
case OP_INVERT:
return "INVERT";
case OP_AND:
return "AND";
case OP_OR:
return "OR";
case OP_XOR:
return "XOR";
case OP_EQUAL:
return "EQUAL";
case OP_EQUALVERIFY:
return "EQUALVERIFY";
case OP_RESERVED1:
return "RESERVED1";
case OP_RESERVED2:
return "RESERVED2";
case OP_1ADD:
return "1ADD";
case OP_1SUB:
return "1SUB";
case OP_2MUL:
return "2MUL";
case OP_2DIV:
return "2DIV";
case OP_NEGATE:
return "NEGATE";
case OP_ABS:
return "ABS";
case OP_NOT:
return "NOT";
case OP_0NOTEQUAL:
return "0NOTEQUAL";
case OP_ADD:
return "ADD";
case OP_SUB:
return "SUB";
case OP_MUL:
return "MUL";
case OP_DIV:
return "DIV";
case OP_MOD:
return "MOD";
case OP_LSHIFT:
return "LSHIFT";
case OP_RSHIFT:
return "RSHIFT";
case OP_BOOLAND:
return "BOOLAND";
case OP_BOOLOR:
return "BOOLOR";
case OP_NUMEQUAL:
return "NUMEQUAL";
case OP_NUMEQUALVERIFY:
return "NUMEQUALVERIFY";
case OP_NUMNOTEQUAL:
return "NUMNOTEQUAL";
case OP_LESSTHAN:
return "LESSTHAN";
case OP_GREATERTHAN:
return "GREATERTHAN";
case OP_LESSTHANOREQUAL:
return "LESSTHANOREQUAL";
case OP_GREATERTHANOREQUAL:
return "GREATERTHANOREQUAL";
case OP_MIN:
return "MIN";
case OP_MAX:
return "MAX";
case OP_WITHIN:
return "WITHIN";
case OP_RIPEMD160:
return "RIPEMD160";
case OP_SHA1:
return "SHA1";
case OP_SHA256:
return "SHA256";
case OP_HASH160:
return "HASH160";
case OP_HASH256:
return "HASH256";
case OP_CODESEPARATOR:
return "CODESEPARATOR";
case OP_CHECKSIG:
return "CHECKSIG";
case OP_CHECKSIGVERIFY:
return "CHECKSIGVERIFY";
case OP_CHECKMULTISIG:
return "CHECKMULTISIG";
case OP_CHECKMULTISIGVERIFY:
return "CHECKMULTISIGVERIFY";
case OP_NOP1:
return "NOP1";
case OP_NOP2:
return "NOP2";
case OP_NOP3:
return "NOP3";
case OP_NOP4:
return "NOP4";
case OP_NOP5:
return "NOP5";
case OP_NOP6:
return "NOP6";
case OP_NOP7:
return "NOP7";
case OP_NOP8:
return "NOP8";
case OP_NOP9:
return "NOP9";
case OP_NOP10:
return "NOP10";
default:
return "NON_OP(" + opcode + ")";
}
}
private byte[] getData(int len) throws ScriptException {
if (len > program.length - cursor)
throw new ScriptException("Failed read of " + len + " bytes");
try {
byte[] buf = new byte[len];
System.arraycopy(program, cursor, buf, 0, len);
cursor += len;
return buf;
} catch (ArrayIndexOutOfBoundsException e) {
// We want running out of data in the array to be treated as a handleable script parsing exception,
// not something that abnormally terminates the app.
throw new ScriptException("Failed read of " + len + " bytes", e);
} catch (NegativeArraySizeException e) {
// We want running out of data in the array to be treated as a handleable script parsing exception,
// not something that abnormally terminates the app.
throw new ScriptException("Failed read of " + len + " bytes", e);
}
}
private int readByte() throws ScriptException {
try {
return 0xFF & program[cursor++];
} catch (ArrayIndexOutOfBoundsException e) {
throw new ScriptException("Attempted to read outside of script boundaries");
}
}
/**
* To run a script, first we parse it which breaks it up into chunks representing pushes of
* data or logical opcodes. Then we can run the parsed chunks.
* <p/>
* The reason for this split, instead of just interpreting directly, is to make it easier
* to reach into a programs structure and pull out bits of data without having to run it.
* This is necessary to render the to/from addresses of transactions in a user interface.
* The official client does something similar.
*/
private void parse(byte[] programBytes, int offset, int length) throws ScriptException {
// TODO: this is inefficient
program = new byte[length];
System.arraycopy(programBytes, offset, program, 0, length);
offset = 0;
chunks = new ArrayList<ScriptChunk>(10); // Arbitrary choice of initial size.
cursor = offset;
while (cursor < offset + length) {
int startLocationInProgram = cursor - offset;
int opcode = readByte();
if (opcode >= 0 && opcode < OP_PUSHDATA1) {
// Read some bytes of data, where how many is the opcode value itself.
chunks.add(new ScriptChunk(false, getData(opcode), startLocationInProgram)); // opcode == len here.
} else if (opcode == OP_PUSHDATA1) {
int len = readByte();
chunks.add(new ScriptChunk(false, getData(len), startLocationInProgram));
} else if (opcode == OP_PUSHDATA2) {
// Read a short, then read that many bytes of data.
int len = readByte() | (readByte() << 8);
chunks.add(new ScriptChunk(false, getData(len), startLocationInProgram));
} else if (opcode == OP_PUSHDATA4) {
// Read a uint32, then read that many bytes of data.
// Though this is allowed, because its value cannot be > 520, it should never actually be used
long len = readByte() | (readByte() << 8) | (readByte() << 16) | (readByte() << 24);
chunks.add(new ScriptChunk(false, getData((int)len), startLocationInProgram));
} else {
chunks.add(new ScriptChunk(true, new byte[]{(byte) opcode}, startLocationInProgram));
}
}
}
/**
* Returns true if this script is of the form <sig> OP_CHECKSIG. This form was originally intended for transactions
* where the peers talked to each other directly via TCP/IP, but has fallen out of favor with time due to that mode
* of operation being susceptible to man-in-the-middle attacks. It is still used in coinbase outputs and can be
* useful more exotic types of transaction, but today most payments are to addresses.
*/
public boolean isSentToRawPubKey() {
if (chunks.size() != 2)
return false;
return chunks.get(1).equalsOpCode(OP_CHECKSIG) &&
!chunks.get(0).isOpCode && chunks.get(0).data.length > 1;
}
/**
* Returns true if this script is of the form DUP HASH160 <pubkey hash> EQUALVERIFY CHECKSIG, ie, payment to an
* address like 1VayNert3x1KzbpzMGt2qdqrAThiRovi8. This form was originally intended for the case where you wish
* to send somebody money with a written code because their node is offline, but over time has become the standard
* way to make payments due to the short and recognizable base58 form addresses come in.
*/
public boolean isSentToAddress() {
if (chunks.size() != 5) return false;
return chunks.get(0).equalsOpCode(OP_DUP) &&
chunks.get(1).equalsOpCode(OP_HASH160) &&
chunks.get(2).data.length == Address.LENGTH &&
chunks.get(3).equalsOpCode(OP_EQUALVERIFY) &&
chunks.get(4).equalsOpCode(OP_CHECKSIG);
}
/**
* If a program matches the standard template DUP HASH160 <pubkey hash> EQUALVERIFY CHECKSIG
* then this function retrieves the third element, otherwise it throws a ScriptException.<p>
*
* This is useful for fetching the destination address of a transaction.
*/
public byte[] getPubKeyHash() throws ScriptException {
if (!isSentToAddress())
throw new ScriptException("Script not in the standard scriptPubKey form");
// Otherwise, the third element is the hash of the public key, ie the feathercoin address.
return chunks.get(2).data;
}
/**
* Returns the public key in this script. If a script contains two constants and nothing else, it is assumed to
* be a scriptSig (input) for a pay-to-address output and the second constant is returned (the first is the
* signature). If a script contains a constant and an OP_CHECKSIG opcode, the constant is returned as it is
* assumed to be a direct pay-to-key scriptPubKey (output) and the first constant is the public key.
*
* @throws ScriptException if the script is none of the named forms.
*/
public byte[] getPubKey() throws ScriptException {
if (chunks.size() != 2) {
throw new ScriptException("Script not of right size, expecting 2 but got " + chunks.size());
}
if (chunks.get(0).data.length > 2 && chunks.get(1).data.length > 2) {
// If we have two large constants assume the input to a pay-to-address output.
return chunks.get(1).data;
} else if (chunks.get(1).data.length == 1 && chunks.get(1).equalsOpCode(OP_CHECKSIG) && chunks.get(0).data.length > 2) {
// A large constant followed by an OP_CHECKSIG is the key.
return chunks.get(0).data;
} else {
throw new ScriptException("Script did not match expected form: " + toString());
}
}
/**
* Convenience wrapper around getPubKey. Only works for scriptSigs.
*/
public Address getFromAddress() throws ScriptException {
return new Address(params, Utils.sha256hash160(getPubKey()));
}
/**
* Gets the destination address from this script, if it's in the required form (see getPubKey).
*
* @throws ScriptException
*/
public Address getToAddress() throws ScriptException {
return new Address(params, getPubKeyHash());
}
////////////////////// Interface for writing scripts from scratch ////////////////////////////////
/**
* Writes out the given byte buffer to the output stream with the correct opcode prefix
* To write an integer call writeBytes(out, Utils.reverseBytes(Utils.encodeMPI(val, false)));
*/
static void writeBytes(OutputStream os, byte[] buf) throws IOException {
if (buf.length < OP_PUSHDATA1) {
os.write(buf.length);
os.write(buf);
} else if (buf.length < 256) {
os.write(OP_PUSHDATA1);
os.write(buf.length);
os.write(buf);
} else if (buf.length < 65536) {
os.write(OP_PUSHDATA2);
os.write(0xFF & (buf.length));
os.write(0xFF & (buf.length >> 8));
os.write(buf);
} else {
throw new RuntimeException("Unimplemented");
}
}
public static byte[] createOutputScript(Address to) {
try {
// TODO: Do this by creating a Script *first* then having the script reassemble itself into bytes.
ByteArrayOutputStream bits = new UnsafeByteArrayOutputStream(24);
bits.write(OP_DUP);
bits.write(OP_HASH160);
writeBytes(bits, to.getHash160());
bits.write(OP_EQUALVERIFY);
bits.write(OP_CHECKSIG);
return bits.toByteArray();
} catch (IOException e) {
throw new RuntimeException(e); // Cannot happen.
}
}
/**
* Create a script that sends coins directly to the given public key (eg in a coinbase transaction).
*/
public static byte[] createOutputScript(byte[] pubkey) {
try {
// TODO: Do this by creating a Script *first* then having the script reassemble itself into bytes.
ByteArrayOutputStream bits = new UnsafeByteArrayOutputStream(pubkey.length + 1);
writeBytes(bits, pubkey);
bits.write(OP_CHECKSIG);
return bits.toByteArray();
} catch (IOException e) {
throw new RuntimeException(e); // Cannot happen.
}
}
/**
* Creates a script that sends coins directly to the given public key. Same as
* {@link Script#createOutputScript(byte[])} but more type safe.
*/
public static byte[] createOutputScript(ECKey pubkey) {
return createOutputScript(pubkey.getPubKey());
}
public static byte[] createInputScript(byte[] signature, byte[] pubkey) {
try {
// TODO: Do this by creating a Script *first* then having the script reassemble itself into bytes.
ByteArrayOutputStream bits = new UnsafeByteArrayOutputStream(signature.length + pubkey.length + 2);
writeBytes(bits, signature);
writeBytes(bits, pubkey);
return bits.toByteArray();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public static byte[] createInputScript(byte[] signature) {
try {
// TODO: Do this by creating a Script *first* then having the script reassemble itself into bytes.
ByteArrayOutputStream bits = new UnsafeByteArrayOutputStream(signature.length + 2);
writeBytes(bits, signature);
return bits.toByteArray();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
////////////////////// Interface used during verification of transactions/blocks ////////////////////////////////
private static int getSigOpCount(List<ScriptChunk> chunks, boolean accurate) throws ScriptException {
int sigOps = 0;
int lastOpCode = OP_INVALIDOPCODE;
for (ScriptChunk chunk : chunks) {
if (chunk.isOpCode) {
int opcode = 0xFF & chunk.data[0];
switch (opcode) {
case OP_CHECKSIG:
case OP_CHECKSIGVERIFY:
sigOps++;
break;
case OP_CHECKMULTISIG:
case OP_CHECKMULTISIGVERIFY:
if (accurate && lastOpCode >= OP_1 && lastOpCode <= OP_16)
sigOps += getOpNValue(lastOpCode);
else
sigOps += 20;
break;
default:
break;
}
lastOpCode = opcode;
}
}
return sigOps;
}
/**
* Convince method to get the int value of OP_N
*/
private static int getOpNValue(int opcode) throws ScriptException {
if (opcode == OP_0)
return 0;
if (opcode < OP_1 || opcode > OP_16) // This should absolutely never happen
throw new ScriptException("getOpNValue called on non OP_N opcode");
return opcode + 1 - OP_1;
}
/**
* Gets the count of regular SigOps in the script program (counting multisig ops as 20)
*/
public static int getSigOpCount(byte[] program) throws ScriptException {
Script script = new Script();
try {
script.parse(program, 0, program.length);
} catch (ScriptException e) {
// Ignore errors and count up to the parse-able length
}
return getSigOpCount(script.chunks, false);
}
/**
* Gets the count of P2SH Sig Ops in the Script scriptSig
*/
public static long getP2SHSigOpCount(byte[] scriptSig) throws ScriptException {
Script script = new Script();
try {
script.parse(scriptSig, 0, scriptSig.length);
} catch (ScriptException e) {
// Ignore errors and count up to the parse-able length
}
for (int i = script.chunks.size() - 1; i >= 0; i--)
if (!script.chunks.get(i).isOpCode) {
Script subScript = new Script();
subScript.parse(script.chunks.get(i).data, 0, script.chunks.get(i).data.length);
return getSigOpCount(subScript.chunks, true);
}
return 0;
}
/**
* <p>Whether or not this is a scriptPubKey representing a pay-to-script-hash output. In such outputs, the logic that
* controls reclamation is not actually in the output at all. Instead there's just a hash, and it's up to the
* spending input to provide a program matching that hash. This rule is "soft enforced" by the network as it does
* not exist in Satoshis original implementation. It means blocks containing P2SH transactions that don't match
* correctly are considered valid, but won't be mined upon, so they'll be rapidly re-orgd out of the chain. This
* logic is defined by <a href="https://en.feathercoin.it/wiki/BIP_0016">BIP 16</a>.</p>
*
* <p>feathercoinj does not support creation of P2SH transactions today. The goal of P2SH is to allow short addresses
* even for complex scripts (eg, multi-sig outputs) so they are convenient to work with in things like QRcodes or
* with copy/paste, and also to minimize the size of the unspent output set (which improves performance of the
* Feathercoin system).</p>
*/
public boolean isPayToScriptHash() {
return program.length == 23 &&
(program[0] & 0xff) == OP_HASH160 &&
(program[1] & 0xff) == 0x14 &&
(program[22] & 0xff) == OP_EQUAL;
}
private static boolean equalsRange(byte[] a, int start, byte[] b) {
if (start + b.length > a.length)
return false;
for (int i = 0; i < b.length; i++)
if (a[i + start] != b[i])
return false;
return true;
}
/**
* Returns the script bytes of inputScript with all instances of the specified script object removed
*/
public static byte[] removeAllInstancesOf(byte[] inputScript, byte[] chunkToRemove) {
// We usually don't end up removing anything
UnsafeByteArrayOutputStream bos = new UnsafeByteArrayOutputStream(inputScript.length);
int cursor = 0;
while (cursor < inputScript.length) {
boolean skip = equalsRange(inputScript, cursor, chunkToRemove);
int opcode = inputScript[cursor++] & 0xFF;
int additionalBytes = 0;
if (opcode >= 0 && opcode < OP_PUSHDATA1) {
additionalBytes = opcode;
} else if (opcode == OP_PUSHDATA1) {
additionalBytes = inputScript[cursor] + 1;
} else if (opcode == OP_PUSHDATA2) {
additionalBytes = ((0xFF & inputScript[cursor]) |
((0xFF & inputScript[cursor+1]) << 8)) + 2;
} else if (opcode == OP_PUSHDATA4) {
additionalBytes = ((0xFF & inputScript[cursor]) |
((0xFF & inputScript[cursor+1]) << 8) |
((0xFF & inputScript[cursor+1]) << 16) |
((0xFF & inputScript[cursor+1]) << 24)) + 4;
}
if (!skip) {
try {
bos.write(opcode);
bos.write(Arrays.copyOfRange(inputScript, cursor, cursor + additionalBytes));
} catch (IOException e) {
throw new RuntimeException(e);
}
}
cursor += additionalBytes;
}
return bos.toByteArray();
}
/**
* Returns the script bytes of inputScript with all instances of the given op code removed
*/
public static byte[] removeAllInstancesOfOp(byte[] inputScript, int opCode) {
return removeAllInstancesOf(inputScript, new byte[] {(byte)opCode});
}
////////////////////// Script verification and helpers ////////////////////////////////
private static boolean castToBool(byte[] data) {
for (int i = 0; i < data.length; i++)
{
// "Can be negative zero" -reference client (see OpenSSL's BN_bn2mpi)
if (data[i] != 0)
return !(i == data.length - 1 && (data[i] & 0xFF) == 0x80);
}
return false;
}
private static BigInteger castToBigInteger(byte[] chunk) throws ScriptException {
if (chunk.length > 4)
throw new ScriptException("Script attempted to use an integer larger than 4 bytes");
return Utils.decodeMPI(Utils.reverseBytes(chunk), false);
}
private static void executeScript(Transaction txContainingThis, long index,
Script script, LinkedList<byte[]> stack) throws ScriptException {
int opCount = 0;
int lastCodeSepLocation = 0;
LinkedList<byte[]> altstack = new LinkedList<byte[]>();
LinkedList<Boolean> ifStack = new LinkedList<Boolean>();
for (ScriptChunk chunk : script.chunks) {
boolean shouldExecute = !ifStack.contains(false);
if (!chunk.isOpCode) {
if (chunk.data.length > 520)
throw new ScriptException("Attempted to push a data string larger than 520 bytes");
if (!shouldExecute)
continue;
stack.add(chunk.data);
} else {
int opcode = 0xFF & chunk.data[0];
if (opcode > OP_16) {
opCount++;
if (opCount > 201)
throw new ScriptException("More script operations than is allowed");
}
if (opcode == OP_VERIF || opcode == OP_VERNOTIF)
throw new ScriptException("Script included OP_VERIF or OP_VERNOTIF");
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)
throw new ScriptException("Script included a disabled Script Op.");
switch (opcode) {
case OP_IF:
if (!shouldExecute) {
ifStack.add(false);
continue;
}
if (stack.size() < 1)
throw new ScriptException("Attempted OP_IF on an empty stack");
ifStack.add(castToBool(stack.pollLast()));
continue;
case OP_NOTIF:
if (!shouldExecute) {
ifStack.add(false);
continue;
}
if (stack.size() < 1)
throw new ScriptException("Attempted OP_NOTIF on an empty stack");
ifStack.add(!castToBool(stack.pollLast()));
continue;
case OP_ELSE:
if (ifStack.isEmpty())
throw new ScriptException("Attempted OP_ELSE without OP_IF/NOTIF");
ifStack.add(!ifStack.pollLast());
continue;
case OP_ENDIF:
if (ifStack.isEmpty())
throw new ScriptException("Attempted OP_ENDIF without OP_IF/NOTIF");
ifStack.pollLast();
continue;
}
if (!shouldExecute)
continue;
switch(opcode) {
//case OP_0: dont know why this isnt also here in the reference client
case OP_1NEGATE:
stack.add(Utils.reverseBytes(Utils.encodeMPI(BigInteger.ONE.negate(), false)));
break;
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:
stack.add(Utils.reverseBytes(Utils.encodeMPI(BigInteger.valueOf(getOpNValue(opcode)), false)));
break;
case OP_NOP:
break;
case OP_VERIFY:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_VERIFY on an empty stack");
if (!castToBool(stack.pollLast()))
throw new ScriptException("OP_VERIFY failed");
break;
case OP_RETURN:
throw new ScriptException("Script called OP_RETURN");
case OP_TOALTSTACK:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_TOALTSTACK on an empty stack");
altstack.add(stack.pollLast());
break;
case OP_FROMALTSTACK:
if (altstack.size() < 1)
throw new ScriptException("Attempted OP_TOALTSTACK on an empty altstack");
stack.add(altstack.pollLast());
break;
case OP_2DROP:
if (stack.size() < 2)
throw new ScriptException("Attempted OP_2DROP on a stack with size < 2");
stack.pollLast();
stack.pollLast();
break;
case OP_2DUP:
if (stack.size() < 2)
throw new ScriptException("Attempted OP_2DUP on a stack with size < 2");
Iterator<byte[]> it2DUP = stack.descendingIterator();
byte[] OP2DUPtmpChunk2 = it2DUP.next();
stack.add(it2DUP.next());
stack.add(OP2DUPtmpChunk2);
break;
case OP_3DUP:
if (stack.size() < 3)
throw new ScriptException("Attempted OP_3DUP on a stack with size < 3");
Iterator<byte[]> it3DUP = stack.descendingIterator();
byte[] OP3DUPtmpChunk3 = it3DUP.next();
byte[] OP3DUPtmpChunk2 = it3DUP.next();
stack.add(it3DUP.next());
stack.add(OP3DUPtmpChunk2);
stack.add(OP3DUPtmpChunk3);
break;
case OP_2OVER:
if (stack.size() < 4)
throw new ScriptException("Attempted OP_2OVER on a stack with size < 4");
Iterator<byte[]> it2OVER = stack.descendingIterator();
it2OVER.next();
it2OVER.next();
byte[] OP2OVERtmpChunk2 = it2OVER.next();
stack.add(it2OVER.next());
stack.add(OP2OVERtmpChunk2);
break;
case OP_2ROT:
if (stack.size() < 6)
throw new ScriptException("Attempted OP_2ROT on a stack with size < 6");
byte[] OP2ROTtmpChunk6 = stack.pollLast();
byte[] OP2ROTtmpChunk5 = stack.pollLast();
byte[] OP2ROTtmpChunk4 = stack.pollLast();
byte[] OP2ROTtmpChunk3 = stack.pollLast();
byte[] OP2ROTtmpChunk2 = stack.pollLast();
byte[] OP2ROTtmpChunk1 = stack.pollLast();
stack.add(OP2ROTtmpChunk3);
stack.add(OP2ROTtmpChunk4);
stack.add(OP2ROTtmpChunk5);
stack.add(OP2ROTtmpChunk6);
stack.add(OP2ROTtmpChunk1);
stack.add(OP2ROTtmpChunk2);
break;
case OP_2SWAP:
if (stack.size() < 4)
throw new ScriptException("Attempted OP_2SWAP on a stack with size < 4");
byte[] OP2SWAPtmpChunk4 = stack.pollLast();
byte[] OP2SWAPtmpChunk3 = stack.pollLast();
byte[] OP2SWAPtmpChunk2 = stack.pollLast();
byte[] OP2SWAPtmpChunk1 = stack.pollLast();
stack.add(OP2SWAPtmpChunk3);
stack.add(OP2SWAPtmpChunk4);
stack.add(OP2SWAPtmpChunk1);
stack.add(OP2SWAPtmpChunk2);
break;
case OP_IFDUP:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_IFDUP on an empty stack");
if (castToBool(stack.getLast()))
stack.add(stack.getLast());
break;
case OP_DEPTH:
stack.add(Utils.reverseBytes(Utils.encodeMPI(BigInteger.valueOf(stack.size()), false)));
break;
case OP_DROP:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_DROP on an empty stack");
stack.pollLast();
break;
case OP_DUP:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_DUP on an empty stack");
stack.add(stack.getLast());
break;
case OP_NIP:
if (stack.size() < 2)
throw new ScriptException("Attempted OP_NIP on a stack with size < 2");
byte[] OPNIPtmpChunk = stack.pollLast();
stack.pollLast();
stack.add(OPNIPtmpChunk);
break;
case OP_OVER:
if (stack.size() < 2)
throw new ScriptException("Attempted OP_OVER on a stack with size < 2");
Iterator<byte[]> itOVER = stack.descendingIterator();
itOVER.next();
stack.add(itOVER.next());
break;
case OP_PICK:
case OP_ROLL:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_PICK/OP_ROLL on an empty stack");
long val = castToBigInteger(stack.pollLast()).longValue();
if (val < 0 || val >= stack.size())
throw new ScriptException("OP_PICK/OP_ROLL attempted to get data deeper than stack size");
Iterator<byte[]> itPICK = stack.descendingIterator();
for (long i = 0; i < val; i++)
itPICK.next();
byte[] OPROLLtmpChunk = itPICK.next();
if (opcode == OP_ROLL)
itPICK.remove();
stack.add(OPROLLtmpChunk);
break;
case OP_ROT:
if (stack.size() < 3)
throw new ScriptException("Attempted OP_ROT on a stack with size < 3");
byte[] OPROTtmpChunk3 = stack.pollLast();
byte[] OPROTtmpChunk2 = stack.pollLast();
byte[] OPROTtmpChunk1 = stack.pollLast();
stack.add(OPROTtmpChunk2);
stack.add(OPROTtmpChunk3);
stack.add(OPROTtmpChunk1);
break;
case OP_SWAP:
case OP_TUCK:
if (stack.size() < 2)
throw new ScriptException("Attempted OP_SWAP on a stack with size < 2");
byte[] OPSWAPtmpChunk2 = stack.pollLast();
byte[] OPSWAPtmpChunk1 = stack.pollLast();
stack.add(OPSWAPtmpChunk2);
stack.add(OPSWAPtmpChunk1);
if (opcode == OP_TUCK)
stack.add(OPSWAPtmpChunk2);
break;
case OP_CAT:
case OP_SUBSTR:
case OP_LEFT:
case OP_RIGHT:
throw new ScriptException("Attempted to use disabled Script Op.");
case OP_SIZE:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_SIZE on an empty stack");
stack.add(Utils.reverseBytes(Utils.encodeMPI(BigInteger.valueOf(stack.getLast().length), false)));
break;
case OP_INVERT:
case OP_AND:
case OP_OR:
case OP_XOR:
throw new ScriptException("Attempted to use disabled Script Op.");
case OP_EQUAL:
if (stack.size() < 2)
throw new ScriptException("Attempted OP_EQUALVERIFY on a stack with size < 2");
stack.add(Arrays.equals(stack.pollLast(), stack.pollLast()) ? new byte[] {1} : new byte[] {0});
break;
case OP_EQUALVERIFY:
if (stack.size() < 2)
throw new ScriptException("Attempted OP_EQUALVERIFY on a stack with size < 2");
if (!Arrays.equals(stack.pollLast(), stack.pollLast()))
throw new ScriptException("OP_EQUALVERIFY: non-equal data");
break;
case OP_1ADD:
case OP_1SUB:
case OP_NEGATE:
case OP_ABS:
case OP_NOT:
case OP_0NOTEQUAL:
if (stack.size() < 1)
throw new ScriptException("Attempted a numeric op on an empty stack");
BigInteger numericOPnum = castToBigInteger(stack.pollLast());
switch (opcode) {
case OP_1ADD:
numericOPnum = numericOPnum.add(BigInteger.ONE);
break;
case OP_1SUB:
numericOPnum = numericOPnum.subtract(BigInteger.ONE);
break;
case OP_NEGATE:
numericOPnum = numericOPnum.negate();
break;
case OP_ABS:
if (numericOPnum.compareTo(BigInteger.ZERO) < 0)
numericOPnum = numericOPnum.negate();
break;
case OP_NOT:
if (numericOPnum.equals(BigInteger.ZERO))
numericOPnum = BigInteger.ONE;
else
numericOPnum = BigInteger.ZERO;
break;
case OP_0NOTEQUAL:
if (numericOPnum.equals(BigInteger.ZERO))
numericOPnum = BigInteger.ZERO;
else
numericOPnum = BigInteger.ONE;
break;
default:
throw new AssertionError("Unreachable");
}
stack.add(Utils.reverseBytes(Utils.encodeMPI(numericOPnum, false)));
break;
case OP_2MUL:
case OP_2DIV:
throw new ScriptException("Attempted to use disabled Script Op.");
case OP_ADD:
case OP_SUB:
case OP_BOOLAND:
case OP_BOOLOR:
case OP_NUMEQUAL:
case OP_NUMNOTEQUAL:
case OP_LESSTHAN:
case OP_GREATERTHAN:
case OP_LESSTHANOREQUAL:
case OP_GREATERTHANOREQUAL:
case OP_MIN:
case OP_MAX:
if (stack.size() < 2)
throw new ScriptException("Attempted a numeric op on a stack with size < 2");
BigInteger numericOPnum2 = castToBigInteger(stack.pollLast());
BigInteger numericOPnum1 = castToBigInteger(stack.pollLast());
BigInteger numericOPresult;
switch (opcode) {
case OP_ADD:
numericOPresult = numericOPnum1.add(numericOPnum2);
break;
case OP_SUB:
numericOPresult = numericOPnum1.subtract(numericOPnum2);
break;
case OP_BOOLAND:
if (!numericOPnum1.equals(BigInteger.ZERO) && !numericOPnum2.equals(BigInteger.ZERO))
numericOPresult = BigInteger.ONE;
else
numericOPresult = BigInteger.ZERO;
break;
case OP_BOOLOR:
if (!numericOPnum1.equals(BigInteger.ZERO) || !numericOPnum2.equals(BigInteger.ZERO))
numericOPresult = BigInteger.ONE;
else
numericOPresult = BigInteger.ZERO;
break;
case OP_NUMEQUAL:
if (numericOPnum1.equals(numericOPnum2))
numericOPresult = BigInteger.ONE;
else
numericOPresult = BigInteger.ZERO;
break;
case OP_NUMNOTEQUAL:
if (!numericOPnum1.equals(numericOPnum2))
numericOPresult = BigInteger.ONE;
else
numericOPresult = BigInteger.ZERO;
break;
case OP_LESSTHAN:
if (numericOPnum1.compareTo(numericOPnum2) < 0)
numericOPresult = BigInteger.ONE;
else
numericOPresult = BigInteger.ZERO;
break;
case OP_GREATERTHAN:
if (numericOPnum1.compareTo(numericOPnum2) > 0)
numericOPresult = BigInteger.ONE;
else
numericOPresult = BigInteger.ZERO;
break;
case OP_LESSTHANOREQUAL:
if (numericOPnum1.compareTo(numericOPnum2) <= 0)
numericOPresult = BigInteger.ONE;
else
numericOPresult = BigInteger.ZERO;
break;
case OP_GREATERTHANOREQUAL:
if (numericOPnum1.compareTo(numericOPnum2) >= 0)
numericOPresult = BigInteger.ONE;
else
numericOPresult = BigInteger.ZERO;
break;
case OP_MIN:
if (numericOPnum1.compareTo(numericOPnum2) < 0)
numericOPresult = numericOPnum1;
else
numericOPresult = numericOPnum2;
break;
case OP_MAX:
if (numericOPnum1.compareTo(numericOPnum2) > 0)
numericOPresult = numericOPnum1;
else
numericOPresult = numericOPnum2;
break;
default:
throw new RuntimeException("Opcode switched at runtime?");
}
stack.add(Utils.reverseBytes(Utils.encodeMPI(numericOPresult, false)));
break;
case OP_MUL:
case OP_DIV:
case OP_MOD:
case OP_LSHIFT:
case OP_RSHIFT:
throw new ScriptException("Attempted to use disabled Script Op.");
case OP_NUMEQUALVERIFY:
if (stack.size() < 2)
throw new ScriptException("Attempted OP_NUMEQUALVERIFY on a stack with size < 2");
BigInteger OPNUMEQUALVERIFYnum2 = castToBigInteger(stack.pollLast());
BigInteger OPNUMEQUALVERIFYnum1 = castToBigInteger(stack.pollLast());
if (!OPNUMEQUALVERIFYnum1.equals(OPNUMEQUALVERIFYnum2))
throw new ScriptException("OP_NUMEQUALVERIFY failed");
break;
case OP_WITHIN:
if (stack.size() < 3)
throw new ScriptException("Attempted OP_WITHIN on a stack with size < 3");
BigInteger OPWITHINnum3 = castToBigInteger(stack.pollLast());
BigInteger OPWITHINnum2 = castToBigInteger(stack.pollLast());
BigInteger OPWITHINnum1 = castToBigInteger(stack.pollLast());
if (OPWITHINnum2.compareTo(OPWITHINnum1) <= 0 && OPWITHINnum1.compareTo(OPWITHINnum3) < 0)
stack.add(Utils.reverseBytes(Utils.encodeMPI(BigInteger.ONE, false)));
else
stack.add(Utils.reverseBytes(Utils.encodeMPI(BigInteger.ZERO, false)));
break;
case OP_RIPEMD160:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_RIPEMD160 on an empty stack");
RIPEMD160Digest digest = new RIPEMD160Digest();
byte[] dataToHash = stack.pollLast();
digest.update(dataToHash, 0, dataToHash.length);
byte[] ripmemdHash = new byte[20];
digest.doFinal(ripmemdHash, 0);
stack.add(ripmemdHash);
break;
case OP_SHA1:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_SHA1 on an empty stack");
try {
stack.add(MessageDigest.getInstance("SHA-1").digest(stack.pollLast()));
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e); // Cannot happen.
}
break;
case OP_SHA256:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_SHA256 on an empty stack");
try {
stack.add(MessageDigest.getInstance("SHA-256").digest(stack.pollLast()));
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e); // Cannot happen.
}
break;
case OP_HASH160:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_HASH160 on an empty stack");
stack.add(Utils.sha256hash160(stack.pollLast()));
break;
case OP_HASH256:
if (stack.size() < 1)
throw new ScriptException("Attempted OP_SHA256 on an empty stack");
stack.add(Utils.doubleDigest(stack.pollLast()));
break;
case OP_CODESEPARATOR:
lastCodeSepLocation = chunk.startLocationInProgram + 1;
break;
case OP_CHECKSIG:
case OP_CHECKSIGVERIFY:
if (stack.size() < 2)
throw new ScriptException("Attempted OP_CHECKSIG(VERIFY) on a stack with size < 2");
byte[] CHECKSIGpubKey = stack.pollLast();
byte[] CHECKSIGsig = stack.pollLast();
byte[] CHECKSIGconnectedScript = Arrays.copyOfRange(script.program, lastCodeSepLocation, script.program.length);
UnsafeByteArrayOutputStream OPCHECKSIGOutStream = new UnsafeByteArrayOutputStream(CHECKSIGsig.length + 1);
try {
writeBytes(OPCHECKSIGOutStream, CHECKSIGsig);
} catch (IOException e) {
throw new RuntimeException(e); // Cannot happen
}
CHECKSIGconnectedScript = removeAllInstancesOf(CHECKSIGconnectedScript, OPCHECKSIGOutStream.toByteArray());
// TODO: Use int for indexes everywhere, we can't have that many inputs/outputs
Sha256Hash CHECKSIGhash = txContainingThis.hashTransactionForSignature((int)index, CHECKSIGconnectedScript,
CHECKSIGsig[CHECKSIGsig.length - 1]);
boolean CHECKSIGsigValid;
try {
CHECKSIGsigValid = ECKey.verify(CHECKSIGhash.getBytes(), Arrays.copyOf(CHECKSIGsig, CHECKSIGsig.length - 1), CHECKSIGpubKey);
} catch (Exception e1) {
// There is (at least) one exception that could be hit here (EOFException, if the sig is too short)
// Because I can't verify there aren't more, we use a very generic Exception catch
CHECKSIGsigValid = false;
}
if (opcode == OP_CHECKSIG)
stack.add(CHECKSIGsigValid ? new byte[] {1} : new byte[] {0});
else if (opcode == OP_CHECKSIGVERIFY)
if (!CHECKSIGsigValid)
throw new ScriptException("Script failed OP_CHECKSIGVERIFY");
break;
case OP_CHECKMULTISIG:
case OP_CHECKMULTISIGVERIFY:
if (stack.size() < 2)
throw new ScriptException("Attempted OP_CHECKMULTISIG(VERIFY) on a stack with size < 2");
int CHECKMULTISIGpubKeyCount = castToBigInteger(stack.pollLast()).intValue();
if (CHECKMULTISIGpubKeyCount < 0 || CHECKMULTISIGpubKeyCount > 20)
throw new ScriptException("OP_CHECKMULTISIG(VERIFY) with pubkey count out of range");
opCount += CHECKMULTISIGpubKeyCount;
if (opCount > 201)
throw new ScriptException("Total op count > 201 during OP_CHECKMULTISIG(VERIFY)");
if (stack.size() < CHECKMULTISIGpubKeyCount + 1)
throw new ScriptException("Attempted OP_CHECKMULTISIG(VERIFY) on a stack with size < num_of_pubkeys + 2");
LinkedList<byte[]> CHECKMULTISIGpubkeys = new LinkedList<byte[]>();
for (int i = 0; i < CHECKMULTISIGpubKeyCount; i++)
CHECKMULTISIGpubkeys.add(stack.pollLast());
int CHECKMULTISIGsigCount = castToBigInteger(stack.pollLast()).intValue();
if (CHECKMULTISIGsigCount < 0 || CHECKMULTISIGsigCount > CHECKMULTISIGpubKeyCount)
throw new ScriptException("OP_CHECKMULTISIG(VERIFY) with sig count out of range");
if (stack.size() < CHECKMULTISIGsigCount + 1)
throw new ScriptException("Attempted OP_CHECKMULTISIG(VERIFY) on a stack with size < num_of_pubkeys + num_of_signatures + 3");
LinkedList<byte[]> CHECKMULTISIGsigs = new LinkedList<byte[]>();
for (int i = 0; i < CHECKMULTISIGsigCount; i++)
CHECKMULTISIGsigs.add(stack.pollLast());
byte[] CHECKMULTISIGconnectedScript = Arrays.copyOfRange(script.program, lastCodeSepLocation, script.program.length);
for (byte[] CHECKMULTISIGsig : CHECKMULTISIGsigs) {
UnsafeByteArrayOutputStream OPCHECKMULTISIGOutStream = new UnsafeByteArrayOutputStream(CHECKMULTISIGsig.length + 1);
try {
writeBytes(OPCHECKMULTISIGOutStream, CHECKMULTISIGsig);
} catch (IOException e) {
throw new RuntimeException(e); // Cannot happen
}
CHECKMULTISIGconnectedScript = removeAllInstancesOf(CHECKMULTISIGconnectedScript, OPCHECKMULTISIGOutStream.toByteArray());
}
boolean CHECKMULTISIGValid = true;
while (CHECKMULTISIGsigs.size() > 0) {
byte[] CHECKMULTISIGsig = CHECKMULTISIGsigs.getFirst();
byte[] CHECKMULTISIGpubKey = CHECKMULTISIGpubkeys.pollFirst();
// We could reasonably move this out of the loop,
// but because signature verification is significantly more expensive than hashing, its not a big deal
Sha256Hash CHECKMULTISIGhash = txContainingThis.hashTransactionForSignature((int)index, CHECKMULTISIGconnectedScript,
CHECKMULTISIGsig[CHECKMULTISIGsig.length - 1]);
try {
if (ECKey.verify(CHECKMULTISIGhash.getBytes(), Arrays.copyOf(CHECKMULTISIGsig, CHECKMULTISIGsig.length - 1), CHECKMULTISIGpubKey))
CHECKMULTISIGsigs.pollFirst();
} catch (Exception e) {
// There is (at least) one exception that could be hit here (EOFException, if the sig is too short)
// Because I can't verify there aren't more, we use a very generic Exception catch
}
if (CHECKMULTISIGsigs.size() > CHECKMULTISIGpubkeys.size()) {
CHECKMULTISIGValid = false;
break;
}
}
// We uselessly remove a stack object to emulate a reference client bug
stack.pollLast();
if (opcode == OP_CHECKMULTISIG)
stack.add(CHECKMULTISIGValid ? new byte[] {1} : new byte[] {0});
else if (opcode == OP_CHECKMULTISIGVERIFY)
if (!CHECKMULTISIGValid)
throw new ScriptException("Script failed OP_CHECKMULTISIGVERIFY");
break;
case OP_NOP1:
case OP_NOP2:
case OP_NOP3:
case OP_NOP4:
case OP_NOP5:
case OP_NOP6:
case OP_NOP7:
case OP_NOP8:
case OP_NOP9:
case OP_NOP10:
break;
default:
throw new ScriptException("Script used a reserved Op Code");
}
}
if (stack.size() + altstack.size() > 1000 || stack.size() + altstack.size() < 0)
throw new ScriptException("Stack size exceeded range");
}
if (!ifStack.isEmpty())
throw new ScriptException("OP_IF/OP_NOTIF without OP_ENDIF");
}
/**
* Verifies that this script (interpreted as a scriptSig) correctly spends the given scriptPubKey.
* @param txContainingThis The transaction in which this input scriptSig resides.
* @param scriptSigIndex The index in txContainingThis of the scriptSig (note: NOT the index of the scriptPubKey).
* @param scriptPubKey The connected scriptPubKey containing the conditions needed to claim the value.
* @param enforceP2SH Whether "pay to script hash" rules should be enforced. If in doubt, set to true.
* @throws VerificationException if this script does not correctly spend the scriptPubKey
*/
public void correctlySpends(Transaction txContainingThis, long scriptSigIndex, Script scriptPubKey,
boolean enforceP2SH) throws ScriptException {
if (program.length > 10000 || scriptPubKey.program.length > 10000)
throw new ScriptException("Script larger than 10,000 bytes");
LinkedList<byte[]> stack = new LinkedList<byte[]>();
LinkedList<byte[]> p2shStack = null;
executeScript(txContainingThis, scriptSigIndex, this, stack);
if (enforceP2SH)
p2shStack = new LinkedList<byte[]>(stack);
executeScript(txContainingThis, scriptSigIndex, scriptPubKey, stack);
if (stack.size() == 0)
throw new ScriptException("Stack empty at end of script execution.");
if (!castToBool(stack.pollLast()))
throw new ScriptException("Script resulted in a non-true stack");
// P2SH is pay to script hash. It means that the scriptPubKey has a special form which is a valid
// program but it has "useless" form that if evaluated as a normal program always returns true.
// Instead, miners recognize it as special based on its template - it provides a hash of the real scriptPubKey
// and that must be provided by the input. The goal of this bizarre arrangement is twofold:
//
// (1) You can sum up a large, complex script (like a CHECKMULTISIG script) with an address that's the same
// size as a regular address. This means it doesn't overload scannable QR codes/NFC tags or become
// un-wieldy to copy/paste.
// (2) It allows the working set to be smaller: nodes perform best when they can store as many unspent outputs
// in RAM as possible, so if the outputs are made smaller and the inputs get bigger, then it's better for
// overall scalability and performance.
// TODO: Check if we can take out enforceP2SH if there's a checkpoint at the enforcement block.
if (enforceP2SH && scriptPubKey.isPayToScriptHash()) {
for (ScriptChunk chunk : chunks)
if (chunk.isOpCode && (chunk.data[0] & 0xff) > OP_16)
throw new ScriptException("Attempted to spend a P2SH scriptPubKey with a script that contained script ops");
byte[] scriptPubKeyBytes = p2shStack.pollLast();
Script scriptPubKeyP2SH = new Script(params, scriptPubKeyBytes, 0, scriptPubKeyBytes.length);
executeScript(txContainingThis, scriptSigIndex, scriptPubKeyP2SH, p2shStack);
if (p2shStack.size() == 0)
throw new ScriptException("P2SH stack empty at end of script execution.");
if (!castToBool(p2shStack.pollLast()))
throw new ScriptException("P2SH script execution resulted in a non-true stack");
}
}
}