Merge #13721: Bugfixes for BIP 174 combining and deserialization

fad231a Fix merging of global unknown data in PSBTs (Andrew Chow)
41df035 Check that PSBT keys are the correct length (Andrew Chow)

Pull request description:

  This PR fixes a few bugs that were found and adds tests checking for these errors.

  Specifically:
  - Single byte keys are checked to actually be one byte.
  - Unknown global data must be merged when combining two PSBTs.

Tree-SHA512: c0e7b4bc607d510cc005aaa7c0813ee58c5467ab7ce4adce485522dfeee92b1af3d29fe89df778b0ea812bb3827e085b30e04d4f4ebcefd8364d809573991332

Author: laanwj

src/script/sign.cpp

@@ -474,6 +474,7 @@ void PartiallySignedTransaction::Merge(const PartiallySignedTransaction& psbt)
     for (unsigned int i = 0; i < outputs.size(); ++i) {
         outputs[i].Merge(psbt.outputs[i]);
     }
+    unknown.insert(psbt.unknown.begin(), psbt.unknown.end());
 }
 
 bool PartiallySignedTransaction::IsSane() const

src/script/sign.h

@@ -284,12 +284,16 @@ struct PSBTInput
                 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);
                     break;
                 case PSBT_IN_WITNESS_UTXO:
                     if (!witness_utxo.IsNull()) {
                         throw std::ios_base::failure("Duplicate Key, input witness utxo already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure("Witness utxo key is more than one byte type");
                     }
                     UnserializeFromVector(s, witness_utxo);
                     break;
@@ -319,13 +323,17 @@ struct PSBTInput
                 case PSBT_IN_SIGHASH:
                     if (sighash_type > 0) {
                         throw std::ios_base::failure("Duplicate Key, input sighash type already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure("Sighash type key is more than one byte type");
                     }
                     UnserializeFromVector(s, sighash_type);
                     break;
                 case PSBT_IN_REDEEMSCRIPT:
                 {
                     if (!redeem_script.empty()) {
                         throw std::ios_base::failure("Duplicate Key, input redeemScript already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure("Input redeemScript key is more than one byte type");
                     }
                     s >> redeem_script;
                     break;
@@ -334,6 +342,8 @@ struct PSBTInput
                 {
                     if (!witness_script.empty()) {
                         throw std::ios_base::failure("Duplicate Key, input witnessScript already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure("Input witnessScript key is more than one byte type");
                     }
                     s >> witness_script;
                     break;
@@ -347,6 +357,8 @@ struct PSBTInput
                 {
                     if (!final_script_sig.empty()) {
                         throw std::ios_base::failure("Duplicate Key, input final scriptSig already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure("Final scriptSig key is more than one byte type");
                     }
                     s >> final_script_sig;
                     break;
@@ -355,6 +367,8 @@ struct PSBTInput
                 {
                     if (!final_script_witness.IsNull()) {
                         throw std::ios_base::failure("Duplicate Key, input final scriptWitness already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure("Final scriptWitness key is more than one byte type");
                     }
                     UnserializeFromVector(s, final_script_witness.stack);
                     break;
@@ -442,6 +456,8 @@ struct PSBTOutput
                 {
                     if (!redeem_script.empty()) {
                         throw std::ios_base::failure("Duplicate Key, output redeemScript already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure("Output redeemScript key is more than one byte type");
                     }
                     s >> redeem_script;
                     break;
@@ -450,6 +466,8 @@ struct PSBTOutput
                 {
                     if (!witness_script.empty()) {
                         throw std::ios_base::failure("Duplicate Key, output witnessScript already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure("Output witnessScript key is more than one byte type");
                     }
                     s >> witness_script;
                     break;
@@ -564,6 +582,8 @@ struct PartiallySignedTransaction
                 {
                     if (tx) {
                         throw std::ios_base::failure("Duplicate Key, unsigned tx already provided");
+                    } else if (key.size() != 1) {
+                        throw std::ios_base::failure("Global unsigned tx key is more than one byte type");
                     }
                     CMutableTransaction mtx;
                     UnserializeFromVector(s, mtx);