Merge #13960: Fix PSBT deserialization of 0-input transactions

bd19cc7 Serialize non-witness utxo as a non-witness tx but always deserialize as witness (Andrew Chow)
43811e6 Fix PSBT deserialization of 0-input transactions (Andrew Chow)

Pull request description:

  0-input transactions can be ambiguously deserialized as being witness transactions. Since the unsigned transaction is never serialized as a witness transaction as it has no witnesses, we should always deserialize it as a non-witness transaction and set the serialization flags as such.

  When a transaction is serliazed for the non-witness-utxo, it is always a valid network transaction and thus it should be always be deserialized as a witness transaction and the deserialzation flags are set as such.

  Fixes #13958

Tree-SHA512: 1937b3cb2618534478d4f533541fb9efce3cb5badb5d1964bfe19400f4aacc6c8ecedaf1f20d26b20baf94f81fd07dfb15b3b08089ecbd63aeecbc18c7c48086

Author: laanwj

src/script/sign.h

@@ -223,7 +223,8 @@ struct PSBTInput
         // If there is a non-witness utxo, then don't add the witness one.
         if (non_witness_utxo) {
             SerializeToVector(s, PSBT_IN_NON_WITNESS_UTXO);
-            SerializeToVector(s, non_witness_utxo);
+            OverrideStream<Stream> os(&s, s.GetType(), s.GetVersion() | SERIALIZE_TRANSACTION_NO_WITNESS);
+            SerializeToVector(os, non_witness_utxo);
         } else if (!witness_utxo.IsNull()) {
             SerializeToVector(s, PSBT_IN_WITNESS_UTXO);
             SerializeToVector(s, witness_utxo);
@@ -297,13 +298,17 @@ struct PSBTInput
             // Do stuff based on type
             switch(type) {
                 case PSBT_IN_NON_WITNESS_UTXO:
+                {
                     if (non_witness_utxo) {
                         throw std::ios_base::failure("Duplicate Key, input non-witness utxo already provided");
                     } else if (key.size() != 1) {
                         throw std::ios_base::failure("Non-witness utxo key is more than one byte type");
                     }
-                    UnserializeFromVector(s, non_witness_utxo);
+                    // Set the stream to unserialize with witness since this is always a valid network transaction
+                    OverrideStream<Stream> os(&s, s.GetType(), s.GetVersion() & ~SERIALIZE_TRANSACTION_NO_WITNESS);
+                    UnserializeFromVector(os, non_witness_utxo);
                     break;
+                }
                 case PSBT_IN_WITNESS_UTXO:
                     if (!witness_utxo.IsNull()) {
                         throw std::ios_base::failure("Duplicate Key, input witness utxo already provided");
@@ -547,7 +552,8 @@ struct PartiallySignedTransaction
         SerializeToVector(s, PSBT_GLOBAL_UNSIGNED_TX);
 
         // Write serialized tx to a stream
-        SerializeToVector(s, *tx);
+        OverrideStream<Stream> os(&s, s.GetType(), s.GetVersion() | SERIALIZE_TRANSACTION_NO_WITNESS);
+        SerializeToVector(os, *tx);
 
         // Write the unknown things
         for (auto& entry : unknown) {
@@ -601,7 +607,9 @@ struct PartiallySignedTransaction
                         throw std::ios_base::failure("Global unsigned tx key is more than one byte type");
                     }
                     CMutableTransaction mtx;
-                    UnserializeFromVector(s, mtx);
+                    // Set the stream to serialize with non-witness since this should always be non-witness
+                    OverrideStream<Stream> os(&s, s.GetType(), s.GetVersion() | SERIALIZE_TRANSACTION_NO_WITNESS);
+                    UnserializeFromVector(os, mtx);
                     tx = std::move(mtx);
                     // Make sure that all scriptSigs and scriptWitnesses are empty
                     for (const CTxIn& txin : tx->vin) {

src/streams.h

@@ -61,6 +61,7 @@ class OverrideStream
 
     int GetVersion() const { return nVersion; }
     int GetType() const { return nType; }
+    size_t size() const { return stream->size(); }
 };
 
 template<typename S>

test/functional/data/rpc_psbt.json

@@ -24,7 +24,8 @@
         "cHNidP8BAKACAAAAAqsJSaCMWvfEm4IS9Bfi8Vqz9cM9zxU4IagTn4d6W3vkAAAAAAD+////qwlJoIxa98SbghL0F+LxWrP1wz3PFTghqBOfh3pbe+QBAAAAAP7///8CYDvqCwAAAAAZdqkUdopAu9dAy+gdmI5x3ipNXHE5ax2IrI4kAAAAAAAAGXapFG9GILVT+glechue4O/p+gOcykWXiKwAAAAAAAEHakcwRAIgR1lmF5fAGwNrJZKJSGhiGDR9iYZLcZ4ff89X0eURZYcCIFMJ6r9Wqk2Ikf/REf3xM286KdqGbX+EhtdVRs7tr5MZASEDXNxh/HupccC1AaZGoqg7ECy0OIEhfKaC3Ibi1z+ogpIAAQEgAOH1BQAAAAAXqRQ1RebjO4MsRwUPJNPuuTycA5SLx4cBBBYAFIXRNTfy4mVAWjTbr6nj3aAfuCMIAAAA",
         "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",
         "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",
-        "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"
+        "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",
+        "cHNidP8BACoCAAAAAAFAQg8AAAAAABepFG6Rty1Vk+fUOR4v9E6R6YXDFkHwhwAAAAAAAA=="
     ],
     "creator" : [
         {