From b6d067ec935dd49fce550a25315c756ac8114b34 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Wed, 4 Jul 2018 14:30:18 -0700
Subject: [PATCH] consensus: fail early on pow check when target > 256 bits.

---
 lib/protocol/consensus.js | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/protocol/consensus.js b/lib/protocol/consensus.js
index d144108a..36f8e072 100644
--- a/lib/protocol/consensus.js
+++ b/lib/protocol/consensus.js
@@ -323,6 +323,9 @@ exports.verifyPOW = function verifyPOW(hash, bits) {
   if (target.isNeg() || target.isZero())
     return false;
 
+  if (target.bitLength() > 256)
+    return false;
+
   const num = new BN(hash, 'le');
 
   if (num.gt(target))