From adb304748f221eeb12914a4bd328cf95126b219c Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Mon, 8 Feb 2016 19:55:56 -0800
Subject: [PATCH] add some data integrity checks when loading the chain.

---
 lib/bcoin/chain.js | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index ecf97622..dedfc683 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -97,23 +97,36 @@ Chain.prototype._init = function _init() {
 
   utils.nextTick(function() {
     var count = self.db.count();
-    var entry;
+    var lastEntry;
     var i = 1;
 
-    function done() {
+    function done(height) {
+      if (height != null) {
+        utils.debug(
+          'Blockchain is corrupt after height %d. Resetting.',
+          height);
+        self.resetHeight(height);
+      } else {
+        utils.debug('Chain successfully loaded.');
+      }
       self.loading = false;
       self.emit('load');
-
-      utils.debug('Chain successfully loaded.');
     }
 
     (function next() {
       if (i >= count)
         return done();
+
       self.db.getAsync(i, function(err, entry) {
         if (err)
           throw err;
+
+        // Do some paranoid checks.
+        if (lastEntry && entry.prevBlock !== lastEntry.hash)
+          return done(Math.max(0, i - 2));
+
         self._saveEntry(entry);
+        lastEntry = entry;
         i += 1;
         next();
       });