normalize DER signature length.

lib/bcoin/pool.js

@@ -295,7 +295,7 @@ Pool.prototype.startServer = function startServer() {
 
   this.server.on('connection', function(socket) {
     self._addLeech(socket);
-  })
+  });
 
   this.server.on('listening', function() {
     var data = self.server.address();

lib/bcoin/script.js

@@ -304,6 +304,11 @@ script.checksig = function checksig(msg, sig, key) {
 
   sig = sig.slice(0, -1);
 
+  // Attempt to normalize the signature
+  // length before passing to elliptic.
+  // https://github.com/indutny/elliptic/issues/78
+  sig = script.normalizeDER(sig);
+
   // Use a try catch in case there are
   // any uncaught errors for bad inputs in verify().
   try {
@@ -311,6 +316,11 @@ script.checksig = function checksig(msg, sig, key) {
   } catch (e) {
     utils.debug('Elliptic threw during verification:');
     utils.debug(e.stack + '');
+    utils.debug({
+      msg: utils.toHex(msg),
+      sig: utils.toHex(sig),
+      key: utils.toHex(key)
+    });
     return false;
   }
 };
@@ -340,6 +350,56 @@ script.sign = function sign(msg, key, type) {
   return sig;
 };
 
+script.normalizeDER = function normalizeDER(signature) {
+  var data, p, len, rlen, slen;
+
+  if (Buffer.isBuffer(signature))
+    signature = Array.prototype.slice.call(signature);
+  else if (typeof signature === 'string')
+    signature = utils.toArray(signature, 'hex');
+
+  data = signature.slice();
+  p = { place: 0 };
+
+  if (data[p.place++] !== 0x30)
+    return signature;
+
+  len = getLength(data, p);
+
+  if (data.length > len + p.place)
+    data = data.slice(0, len + p.place);
+
+  if (data[p.place++] !== 0x02)
+    return signature;
+
+  rlen = getLength(data, p);
+  p.place += rlen;
+
+  if (data[p.place++] !== 0x02)
+    return signature;
+
+  slen = getLength(data, p);
+  if (data.length > slen + p.place)
+    data = data.slice(0, slen + p.place);
+
+  return data;
+};
+
+function getLength(buf, p) {
+  var initial = buf[p.place++];
+  if (!(initial & 0x80)) {
+    return initial;
+  }
+  var octetLen = initial & 0xf;
+  var val = 0;
+  for (var i = 0, off = p.place; i < octetLen; i++, off++) {
+    val <<= 8;
+    val |= buf[off];
+  }
+  p.place = off;
+  return val;
+}
+
 script._next = function _next(to, s, pc) {
   var depth = 0;
   var o;