improve locktime checks and coinbase parsing.

lib/bcoin/block.js

@@ -62,7 +62,7 @@ function Block(data, subtype) {
     if (this.version >= 2) {
       tx = this.txs[0];
       if (tx && tx.inputs[0] && +tx.inputs[0].out.hash === 0) {
-        height = bcoin.script.coinbaseHeight(tx.inputs[0].script);
+        height = bcoin.script.coinbaseHeight(tx.inputs[0].script, this);
         if (height > 0)
           this._height = height;
       }

lib/bcoin/script.js

@@ -384,7 +384,10 @@ script.execute = function execute(s, stack, tx, index, recurse) {
       case 'roll': {
         if (stack.length < 2)
           return false;
-        n = new bn(stack.pop()).toNumber();
+        v = stack.pop();
+        if (v.length > 6)
+          return false;
+        n = new bn(v).toNumber();
         if (n < 0 || n >= stack.length)
           return false;
         v = stack[-n - 1];
@@ -772,7 +775,15 @@ script.execute = function execute(s, stack, tx, index, recurse) {
         if (!tx || stack.length === 0)
           return false;
 
-        lock = new bn(stack[stack.length - 1]).toNumber();
+        lock = stack[stack.length - 1];
+
+        if (!Array.isArray(lock))
+          return false;
+
+        if (lock.length > 6)
+          return false;
+
+        lock = new bn(lock).toNumber();
 
         if (lock < 0)
           return false;
@@ -878,11 +889,20 @@ script.standard = function standard(s) {
 };
 
 script.lockTime = function lockTime(s) {
-  return s.length > 3
+  var lock = s[0];
+  var res = s.length > 3
     && Array.isArray(s[0])
     && s[1] === 'checklocktimeverify'
-    && s[2] === 'drop'
-    && new bn(s[0]);
+    && s[2] === 'drop';
+
+  if (!res)
+    return false;
+
+  // Number can only store 6 & 5/8 bytes
+  if (lock.length > 6)
+    lock = [0x1f].concat(lock.slice(0, 6));
+
+  return new bn(lock);
 };
 
 script.spendable = function spendable(s, lockTime) {
@@ -1138,38 +1158,84 @@ script.isScripthashInput = function isScripthashInput(s, redeem) {
   return keys;
 };
 
-script.coinbaseHeight = function coinbaseHeight(s) {
-  var raw = s._raw || script.encode(s);
-  var height;
+script.coinbaseBits = function coinbaseBits(s, block) {
+  var value;
 
   if (!Array.isArray(s[0]))
-    return -1;
+    return { type: 'value', value: s[0] };
 
-  if (raw[0] < 0x03 || s[0].length < 3)
-    return -1;
+  // Number can only store up to 53 bits (6 & 5/8 bytes)
+  if (s[0].length > 6)
+    return { type: 'value', value: s[0] };
 
-  height = new bn(s[0].reverse()).toNumber();
+  value = new bn(s[0].reverse()).toNumber();
+
+  if (block) {
+    if (value === block.bits)
+      return { type: 'bits', value: value };
+
+    if (value === block.ts)
+      return { type: 'ts', value: value };
+
+    if (block.version < 2)
+      return { type: 'value', value: value };
+  }
 
   // Last v1 block
-  if (height < 227835)
-    return -1;
+  if (s[0].length < 3 || value < 227835)
+    return { type: 'value', value: value };
 
-  return height;
+  return { type: 'height', value: value };
 };
 
-script.coinbase = function coinbase(s) {
-  var raw = s._raw || script.encode(s);
-  var data = script.coinbaseHeight(s);
+script.coinbaseHeight = function coinbaseHeight(s, block) {
+  var data = script.coinbaseBits(s, block);
+  if (data.type !== 'height')
+    return -1;
+  return data.value;
+};
 
-  if (height > 0)
-    raw = raw.slice(raw[0] + 1);
+script.coinbase = function coinbase(s, block) {
+  var coinbase, data, nonce, flags;
 
-  return {
-    height: height,
+  coinbase = {
     script: s,
-    data: raw,
-    text: utils.array2utf8(raw)
+    raw: s._raw || script.encode(s)
   };
+
+  data = script.coinbaseBits(s, block);
+
+  if (Array.isArray(s[1]))
+    nonce = new bn(s[1]);
+
+  flags = s.slice(2);
+
+  coinbase[data.type] = data.value;
+  coinbase.nonce = nonce;
+  coinbase.flags = flags;
+  coinbase.text = utils.array2utf8(flags);
+
+  return coinbase;
+};
+
+script.isCoinbase = function isCoinbase(s, block) {
+  var coinbase = script.coinbase(s, block);
+
+  if (coinbase.raw.length > 100 || s.length < 2)
+    return false;
+
+  if (coinbase.value != null)
+    return false;
+
+  if (coinbase.nonce == null)
+    return false;
+
+  if (block) {
+    if (coinbase.bits != null && coinbase.flags.length)
+      return false;
+  }
+
+  return coinbase;
 };
 
 // https://github.com/bitcoin/bips/blob/master/bip-0066.mediawiki