Make SignPSBTInput operate on a private SignatureData object

Author: sipa

src/rpc/rawtransaction.cpp

@@ -1641,8 +1641,7 @@ UniValue finalizepsbt(const JSONRPCRequest& request)
     for (unsigned int i = 0; i < psbtx.tx->vin.size(); ++i) {
         PSBTInput& input = psbtx.inputs.at(i);
 
-        SignatureData sigdata;
-        complete &= SignPSBTInput(DUMMY_SIGNING_PROVIDER, *psbtx.tx, input, sigdata, i, 1);
+        complete &= SignPSBTInput(DUMMY_SIGNING_PROVIDER, *psbtx.tx, input, i, 1);
     }
 
     UniValue result(UniValue::VOBJ);

src/script/sign.cpp

@@ -237,14 +237,15 @@ bool ProduceSignature(const SigningProvider& provider, const BaseSignatureCreato
     return sigdata.complete;
 }
 
-bool SignPSBTInput(const SigningProvider& provider, const CMutableTransaction& tx, PSBTInput& input, SignatureData& sigdata, int index, int sighash)
+bool SignPSBTInput(const SigningProvider& provider, const CMutableTransaction& tx, PSBTInput& input, int index, int sighash)
 {
     // if this input has a final scriptsig or scriptwitness, don't do anything with it
     if (!input.final_script_sig.empty() || !input.final_script_witness.IsNull()) {
         return true;
     }
 
     // Fill SignatureData with input info
+    SignatureData sigdata;
     input.FillSignatureData(sigdata);
 
     // Get UTXO
@@ -276,6 +277,16 @@ bool SignPSBTInput(const SigningProvider& provider, const CMutableTransaction& t
     // Verify that a witness signature was produced in case one was required.
     if (require_witness_sig && !sigdata.witness) return false;
     input.FromSignatureData(sigdata);
+
+    // If both UTXO types are present, drop the unnecessary one.
+    if (input.non_witness_utxo && !input.witness_utxo.IsNull()) {
+        if (sigdata.witness) {
+            input.non_witness_utxo = nullptr;
+        } else {
+            input.witness_utxo.SetNull();
+        }
+    }
+
     return sig_complete;
 }
 

src/script/sign.h

@@ -696,7 +696,7 @@ bool SignSignature(const SigningProvider &provider, const CScript& fromPubKey, C
 bool SignSignature(const SigningProvider &provider, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType);
 
 /** Signs a PSBTInput, verifying that all provided data matches what is being signed. */
-bool SignPSBTInput(const SigningProvider& provider, const CMutableTransaction& tx, PSBTInput& input, SignatureData& sigdata, int index, int sighash = 1);
+bool SignPSBTInput(const SigningProvider& provider, const CMutableTransaction& tx, PSBTInput& input, int index, int sighash = SIGHASH_ALL);
 
 /** Extract signature data from a transaction input, and insert it. */
 SignatureData DataFromTransaction(const CMutableTransaction& tx, unsigned int nIn, const CTxOut& txout);

src/wallet/rpcwallet.cpp

@@ -4461,17 +4461,7 @@ bool FillPSBT(const CWallet* pwallet, PartiallySignedTransaction& psbtx, const C
             throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "Specified Sighash and sighash in PSBT do not match.");
         }
 
-        SignatureData sigdata;
-        complete &= SignPSBTInput(HidingSigningProvider(pwallet, !sign, !bip32derivs), *psbtx.tx, input, sigdata, i, sighash_type);
-
-        if (it != pwallet->mapWallet.end()) {
-            // Drop the unnecessary UTXO if we added both from the wallet.
-            if (sigdata.witness) {
-                input.non_witness_utxo = nullptr;
-            } else {
-                input.witness_utxo.SetNull();
-            }
-        }
+        complete &= SignPSBTInput(HidingSigningProvider(pwallet, !sign, !bip32derivs), *psbtx.tx, input, i, sighash_type);
     }
 
     // Fill in the bip32 keypaths and redeemscripts for the outputs so that hardware wallets can identify change