script: interpreter witness program fixes

lib/script/interpreter.js

@@ -32,25 +32,26 @@ var Interpreter = function Interpreter(obj) {
 };
 
 Interpreter.prototype.verifyWitnessProgram = function(version, program, witness, satoshis, flags) {
-  var scriptPubKey = new Script;
+  var scriptPubKey = new Script();
   var stack = [];
 
-  if (version == 0) {
+  if (version === 0) {
     if (program.length == 32) {
       if (witness.length == 0) {
         this.errstr = 'v0 scripthash program empty';
         return false;
       }
 
-      scriptPubKey = witness[witness.length - 1];
-      var hash = Hash.sha256(scriptPubKey);
-      if (hash !== program.script) {
+      var scriptPubKeyBuffer = witness[witness.length - 1];
+      scriptPubKey = new Script(scriptPubKeyBuffer);
+      var hash = Hash.sha256(scriptPubKeyBuffer);
+      if (hash.toString('hex') !== program.toString('hex')) {
         this.errstr = 'witness program mismatch';
         return false;
       }
 
       stack = witness.slice(0, -1);
-    } else if (program.script.length == 20) {
+    } else if (program.length == 20) {
       if (witness.length != 2) {
         this.errstr = 'witness program mismatch';
         return false;
@@ -69,6 +70,7 @@ Interpreter.prototype.verifyWitnessProgram = function(version, program, witness,
     return true;
   }
 
+  this.initialize();
   this.set({
     script: scriptPubKey,
     stack: stack,
@@ -110,7 +112,7 @@ Interpreter.prototype.verifyWitnessProgram = function(version, program, witness,
  *
  * Translated from bitcoind's VerifyScript
  */
-  Interpreter.prototype.verify = function(scriptSig, scriptPubkey, tx, nin, flags, witness, satoshis) {
+Interpreter.prototype.verify = function(scriptSig, scriptPubkey, tx, nin, flags, witness, satoshis) {
 
   var Transaction = require('../transaction');
   if (_.isUndefined(tx)) {
@@ -183,15 +185,14 @@ Interpreter.prototype.verifyWitnessProgram = function(version, program, witness,
   var version, program;
 
   if ((flags & Interpreter.SCRIPT_VERIFY_WITNESS)) {
-    if (scriptPubkey.isWitnessProgram()) {
-      version = scriptPubkey[0];
-      program = s.toProgram();
+    var witnessValues = {};
+    if (scriptPubkey.isWitnessProgram(witnessValues)) {
       hadWitness = true;
       if (scriptSig.toBuffer().length != 0) {
         return false;
       }
 
-      if (!this.verifyWitnessProgram(version, program, witness, satoshis, flags)) {
+      if (!this.verifyWitnessProgram(witnessValues.version, witnessValues.program, witness, satoshis, flags)) {
         return false;
       }
     }
@@ -239,17 +240,18 @@ Interpreter.prototype.verifyWitnessProgram = function(version, program, witness,
       this.errstr = 'SCRIPT_ERR_EVAL_FALSE_IN_P2SH_STACK';
       return false;
     }
-    if ((flags & this.SCRIPT_VERIFY_WITNESS)) {
-      if (redeemScript.isWitnessOut()) {
-        version = redeemScript[0];
-        program = redeemScript.toProgram();
+    if ((flags & Interpreter.SCRIPT_VERIFY_WITNESS)) {
+      var witnessValues = {};
+      if (redeemScript.isWitnessProgram(witnessValues)) {
         hadWitness = true;
-        if (scriptSig !== redeemScript) {
+        var redeemScriptPush = new Script();
+        redeemScriptPush.add(redeemScript.toBuffer());
+        if (scriptSig.toHex() !== redeemScriptPush.toHex()) {
           this.errstr = 'Malleated scriptSig';
           return false;
         }
 
-        if (!this.verifyWitnessProgram(version, program, witness, satoshis, flags)) {
+        if (!this.verifyWitnessProgram(witnessValues.version, witnessValues.program, witness, satoshis, flags)) {
           return false;
         }
 
@@ -257,7 +259,7 @@ Interpreter.prototype.verifyWitnessProgram = function(version, program, witness,
       }
     }
 
-    if ((flags & this.SCRIPT_VERIFY_WITNESS)) {
+    if ((flags & Interpreter.SCRIPT_VERIFY_WITNESS)) {
       if (!hadWitness && witness.length > 0) {
         this.errstr = 'Witness unexpected';
         return false;

lib/script/script.js

@@ -405,29 +405,32 @@ Script.prototype.isWitnessPublicKeyHashOut = function() {
 };
 
 /**
+ * @param {Object=} values - The return values
+ * @param {Number} values.version - Set with the witness version
+ * @param {Buffer} values.program - Set with the witness program
  * @returns {boolean} if this is a p2wpkh output script
  */
-Script.prototype.isWitnessProgram = function() {
+Script.prototype.isWitnessProgram = function(values) {
+  if (!values) {
+    values = {};
+  }
   var buf = this.toBuffer();
   if (buf.length < 4 || buf.length > 34) {
     return false;
   }
-  if (buf[0] !== Opcode.OP_0 && (buf[0] < Opcode.OP_1 && buf[1] > Opcode.OP_16)) {
+  if (buf[0] >= Opcode.OP_0 && (buf[0] < 1 && buf[0] > 16)) {
     return false;
   }
 
-  if (buf.length == buf[1] + 2) {
+  if (buf.length === buf[1] + 2) {
+    values.version = buf[0];
+    values.program = buf.slice(2, buf.length);
     return true;
   }
 
   return false;
 };
 
-Script.prototype.toProgram = function () {
-  var buf = this.toBuffer();
-  return buf.slice(2, buf.end);
-};
-
 /**
  * @returns {boolean} if this is a p2sh input script
  * Note that these are frequently indistinguishable from pubkeyhashin

lib/transaction/transaction.js

@@ -1201,7 +1201,12 @@ Transaction.prototype.verifySignature = function(sig, pubkey, nin, subscript, si
   }
 
   if (sigversion == 1) {
-    return SighashWitness.verify(this, sig, pubkey, nin, subscript, this.inputs[nin].getSatoshisBuffer());
+    var subscriptBuffer = subscript.toBuffer();
+    var scriptCodeWriter = new BufferWriter();
+    scriptCodeWriter.writeVarintNum(subscriptBuffer.length);
+    scriptCodeWriter.write(subscriptBuffer);
+
+    return SighashWitness.verify(this, sig, pubkey, nin, scriptCodeWriter.toBuffer(), this.inputs[nin].getSatoshisBuffer());
   }
 
   return Sighash.verify(this, sig, pubkey, nin, subscript);