Disallow extended encoding for non-witness transactions

sipa · stevenroose · commit e11c6f558091 · 2019-03-21T15:50:35.000Z
diff --git a/src/primitives/transaction.h b/src/primitives/transaction.h
@@ -351,6 +351,10 @@ inline void UnserializeTransaction(TxType& tx, Stream& s) {
             const_cast<CTxWitness*>(&tx.witness)->vtxinwit.resize(tx.vin.size());
             const_cast<CTxWitness*>(&tx.witness)->vtxoutwit.resize(tx.vout.size());
             s >> tx.witness;
+            if (!tx.HasWitness()) {
+                /* It's illegal to encode witnesses when all witness stacks are empty. */
+                throw std::ios_base::failure("Superfluous witness record");
+            }
         }
     } else {
         const bool fAllowWitness = !(s.GetVersion() & SERIALIZE_TRANSACTION_NO_WITNESS);
@@ -381,6 +385,10 @@ inline void UnserializeTransaction(TxType& tx, Stream& s) {
                     s >> tx.witness.vtxinwit[i].m_pegin_witness.stack;
                 }
             }
+            if (!tx.HasWitness()) {
+                /* It's illegal to encode witnesses when all witness stacks are empty. */
+                throw std::ios_base::failure("Superfluous witness record");
+            }
         }
         s >> tx.nLockTime;
     }

Original file line number	Diff line number	Diff line change
`@@ -351,6 +351,10 @@ inline void UnserializeTransaction(TxType& tx, Stream& s) {`
`351`	`351`	`const_cast<CTxWitness*>(&tx.witness)->vtxinwit.resize(tx.vin.size());`
`352`	`352`	`const_cast<CTxWitness*>(&tx.witness)->vtxoutwit.resize(tx.vout.size());`
`353`	`353`	`s >> tx.witness;`
	`354`	`+ if (!tx.HasWitness()) {`
	`355`	`+ /* It's illegal to encode witnesses when all witness stacks are empty. */`
	`356`	`+ throw std::ios_base::failure("Superfluous witness record");`
	`357`	`+ }`
`354`	`358`	`}`
`355`	`359`	`} else {`
`356`	`360`	`const bool fAllowWitness = !(s.GetVersion() & SERIALIZE_TRANSACTION_NO_WITNESS);`
`@@ -381,6 +385,10 @@ inline void UnserializeTransaction(TxType& tx, Stream& s) {`
`381`	`385`	`s >> tx.witness.vtxinwit[i].m_pegin_witness.stack;`
`382`	`386`	`}`
`383`	`387`	`}`
	`388`	`+ if (!tx.HasWitness()) {`
	`389`	`+ /* It's illegal to encode witnesses when all witness stacks are empty. */`
	`390`	`+ throw std::ios_base::failure("Superfluous witness record");`
	`391`	`+ }`
`384`	`392`	`}`
`385`	`393`	`s >> tx.nLockTime;`
`386`	`394`	`}`