From 8719c94c33a00e51c6100c06f3bc229613572de9 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Thu, 23 Aug 2018 17:01:14 -0700
Subject: [PATCH] Disallow extended encoding for non-witness transactions

---
 src/primitives/transaction.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/primitives/transaction.h b/src/primitives/transaction.h
index c1e92f2ecb..91a1d81984 100644
--- a/src/primitives/transaction.h
+++ b/src/primitives/transaction.h
@@ -654,6 +654,10 @@ inline void UnserializeTransaction(TxType& tx, Stream& s) {
         const_cast<CTxWitness*>(&tx.wit)->vtxinwit.resize(tx.vin.size());
         const_cast<CTxWitness*>(&tx.wit)->vtxoutwit.resize(tx.vout.size());
         s >> tx.wit;
+        if (!tx.HasWitness()) {
+            /* It's illegal to encode witnesses when all witness stacks are empty. */
+            throw std::ios_base::failure("Superfluous witness record");
+        }
     }
     if (flags) {
         /* Unknown flag in the serialization */