From e68bab4ab367b7cdf44327f9ee4fd473b2c854de Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Thu, 18 Feb 2016 01:46:29 -0800
Subject: [PATCH] make scripthash input test less insane.

---
 lib/bcoin/script.js | 55 ++++++++++++++-------------------------------
 1 file changed, 17 insertions(+), 38 deletions(-)

diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index 63f4b75b..3574d513 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -1978,8 +1978,8 @@ script.isMultisigInput = function isMultisigInput(s, keys, tx, i) {
   return true;
 };
 
-script.isScripthashInput = function isScripthashInput(s, data, strict) {
-  var raw, redeem;
+script.isScripthashInput = function isScripthashInput(s, redeem) {
+  var raw;
 
   // Grab the raw redeem script.
   raw = s[s.length - 1];
@@ -1994,9 +1994,20 @@ script.isScripthashInput = function isScripthashInput(s, data, strict) {
   if (!Array.isArray(raw))
     return false;
 
-  // If the last data element is a valid
-  // signature or key, it's _extremely_
-  // unlikely this is a scripthash.
+  // Check data against last array in case
+  // a raw redeem script was passed in.
+  if (redeem)
+    return utils.isEqual(redeem, raw);
+
+  // Testing for scripthash inputs requires
+  // some evil magic to work. We do it by
+  // ruling things _out_. This test will not
+  // be correct 100% of the time. We rule
+  // out that the last data element is: a
+  // null dummy, a valid signature, a valid
+  // key, and we ensure that it is at least
+  // a script that does not use undefined
+  // opcodes.
   if (script.isDummy(raw))
     return false;
 
@@ -2006,40 +2017,8 @@ script.isScripthashInput = function isScripthashInput(s, data, strict) {
   if (script.isKeyEncoding(raw))
     return false;
 
-  // Ensure this is a valid encoded script
-  // if (!script.isEncoded(raw))
-  //   return false;
-
-  // Check data against last array in case
-  // a raw redeem script was passed in.
-  if (data && utils.isEqual(data, raw))
-    return true;
-
-  // Return here if we do not want to check
-  // against standard transaction types.
-  if (!strict)
-    return true;
-
-  // P2SH redeem scripts can be nonstandard: make
-  // it easier for other functions to parse this.
-  redeem = script.decode(raw);
-
-  // Get the "real" scriptSig
-  s = s.slice(0, -1);
-
-  // Do some sanity checking on the inputs
-  if (!script.isPubkeyInput(s)
-    && !script.isPubkeyhashInput(s)
-    && !script.isMultisigInput(s)) {
+  if (!script.isEncoded(raw))
     return false;
-  }
-
-  // Test against all other script types
-  if (!script.isPubkey(redeem, data)
-    && !script.isPubkeyhash(redeem, data)
-    && !script.isMultisig(redeem, data)) {
-    return false;
-  }
 
   return true;
 };