From 4f76b9f18c71afaf1de95c8f2f810aa6371ac4a4 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Sat, 5 Dec 2015 18:58:27 -0800
Subject: [PATCH] fix scriptInput/signInput for multisig/p2sh.

---
 lib/bcoin/tx.js     | 51 ++++++++++++++++++++++++++-------------------
 lib/bcoin/wallet.js |  2 +-
 2 files changed, 31 insertions(+), 22 deletions(-)

diff --git a/lib/bcoin/tx.js b/lib/bcoin/tx.js
index b1243ba5..40445e3e 100644
--- a/lib/bcoin/tx.js
+++ b/lib/bcoin/tx.js
@@ -112,7 +112,7 @@ TX.prototype._inputIndex = function _inputIndex(hash, index) {
   return -1;
 };
 
-TX.prototype.signature = function(input, key) {
+TX.prototype.signature = function(input, key, type) {
   // Get the previous output's subscript
   var s = input.out.tx.getSubscript(input.out.index);
 
@@ -142,13 +142,11 @@ TX.prototype.scriptInput = function(input, pub, nsigs) {
   // Multisig
   // raw format: OP_FALSE [sig-1] [sig-2] ...
   if (bcoin.script.isMultisig(s)) {
-    if (!nsigs) {
+    if (!nsigs)
       throw new Error('`nsigs` is required for multisig');
-    }
     input.script = [ constants.opcodes['false'] ];
-    for (var i = 0; i < nsigs; i++) {
+    for (var i = 0; i < nsigs; i++)
       input.script[i + 1] = constants.opcodes['0'];
-    }
     return;
   }
 
@@ -157,21 +155,22 @@ TX.prototype.scriptInput = function(input, pub, nsigs) {
   if (bcoin.script.isScripthash(s)) {
     input.script = [ constants.opcodes['false'] ];
     var m = pub[0] - constants.opcodes['1'] + 1;
-    for (var i = 0; i < m; i++) {
+    for (var i = 0; i < m; i++)
       input.script[i + 1] = constants.opcodes['0'];
-    }
     // P2SH requires the redeem script after signatures
-    if (bcoin.script.isScripthash(s)) {
+    if (bcoin.script.isScripthash(s))
       input.script.push(pub);
-    }
     return;
   }
 
-  throw new Error('could not identify prev_out type');
+  throw new Error('scriptInput(): could not identify prev_out type');
 };
 
 // Sign the now-built scriptSigs
-TX.prototype.signInput = function(input, key) {
+TX.prototype.signInput = function(input, key, type) {
+  if (!type)
+    type = 'all';
+
   // Get the previous output's subscript
   var s = input.out.tx.getSubscript(input.out.index);
 
@@ -191,29 +190,39 @@ TX.prototype.signInput = function(input, key) {
   }
 
   // Multisig
-  // empty array == OP_FALSE == OP_0
   // raw format: OP_FALSE [sig-1] [sig-2] ...
   // p2sh format: OP_FALSE [sig-1] [sig-2] ... [redeem-script]
   if (bcoin.script.isMultisig(s) || bcoin.script.isScripthash(s)) {
-    var l = input.script.length;
-    if (bcoin.script.isScripthash(s)) {
-      l--;
-    }
-    for (var i = 0; i < l; i++) {
-      input.script[i + 1] = signature;
+    var len = input.script.length;
+
+    if (bcoin.script.isScripthash(s))
+      len--;
+
+    for (var i = 1; i < len; i++) {
+      // Already signed
+      if (utils.isEqual(input.script[i], signature))
+        break;
+
+      if (input.script[i] === constants.opcodes['0']) {
+        input.script[i] = signature;
+        break;
+      }
     }
+    return;
   }
+
+  throw new Error('signInput(): could not identify prev_out type');
 };
 
 // Build the scriptSig and sign it
-TX.prototype.scriptSig = function(input, key, pub, nsigs) {
+TX.prototype.scriptSig = function(input, key, pub, type, nsigs) {
   // Build script for input
   tx.scriptInput(input, pub, nsigs);
 
   // Sign input
-  tx.signInput(input, key);
+  tx.signInput(input, key, type);
 
-  return this.input.script;
+  return input.script;
 };
 
 TX.prototype.input = function input(i, index) {
diff --git a/lib/bcoin/wallet.js b/lib/bcoin/wallet.js
index df4579d1..db20d8d9 100644
--- a/lib/bcoin/wallet.js
+++ b/lib/bcoin/wallet.js
@@ -347,7 +347,7 @@ Wallet.prototype.sign = function sign(tx, type, inputs) {
     if (!input.out.tx || !this.ownOutput(input.out.tx))
       return false;
 
-    tx.scriptSig(input, key, pub, nsigs);
+    tx.scriptSig(input, key, pub, type, nsigs);
 
     return true;
   }, this);