I need help signing psbt input

[jerempjerem]

Hi im trying to sign only 2 of 3 inputs in a psbt tx, both input come from UTXO from my nested segwit address, I always get the error: "Signature does not correpond to this input "

Here is my code :

package main

import (
	"bytes"
	"encoding/base64"
	"fmt"

	"github.com/btcsuite/btcd/btcutil"
	"github.com/btcsuite/btcd/btcutil/psbt"
	"github.com/btcsuite/btcd/chaincfg"
	"github.com/btcsuite/btcd/chaincfg/chainhash"
	"github.com/btcsuite/btcd/txscript"
	"github.com/btcsuite/btcd/wire"
)

func GetPayToAddressScript(address_ string) ([]byte, error) {
	address, err := btcutil.DecodeAddress(address_, &chaincfg.MainNetParams)
	if err != nil {
		return nil, err
	}

	pkScript, err := txscript.PayToAddrScript(address)
	if err != nil {
		return nil, err
	}

	return pkScript, nil
}

type PrevOutputFetcher struct {
	Utxos map[wire.OutPoint]*wire.TxOut
}

func (p *PrevOutputFetcher) FetchPrevOutput(outpoint wire.OutPoint) *wire.TxOut {
	return p.Utxos[outpoint]
}

type UTXO struct {
	Txid       string
	Vout       int
	Value      int64
    Address    string
}
 
func main() {
    segwitNestedAddress := "3G1MdfbQQAuqxix9xSBuYRM9r4kGQG1ahv"
    segwitNestedWif := ""
    b64psbt := "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"

    inputToSign := []int{1, 2}


    UTXOs := []UTXO{
        {
            Txid: "cb2323266c701097758810cfb4e8e0b729bb59d278a63f560b0ccb8318dd02e9",
            Vout: 188,
            Value: 546,
            Address: "bc1p8kcxf9lguv70xa02epwra9rzxel9q9dl0rpnfxgje9ghgqf3maks9vgq7h",
        },
        {
            Txid: "3f521838067337af0fe4f95ea81aab2c89db510062986e64d226d9a24c1ff6ac",
            Vout: 0,
            Value: 35468,
            Address: segwitNestedAddress,
        },
        {
            Txid: "2899c7384ce183f71f1e123cdd4ea3a6a1f63724ef41a4f32853badf0f7ea7cf",
            Vout: 0,
            Value: 2000000,
            Address: segwitNestedAddress,
        },
    }

    psbtBytes, err := base64.StdEncoding.DecodeString(b64psbt)
    if err != nil {
        fmt.Println(err)
        return
    }

    packet, err := psbt.NewFromRawBytes(bytes.NewReader(psbtBytes), false)
    if err != nil {
        fmt.Println(err)
        return
    }

    wif, err := btcutil.DecodeWIF(segwitNestedWif)
    if err != nil {
        fmt.Println(err)
        return
    }

    serializedPubKey := wif.SerializePubKey()
    witnessProg := btcutil.Hash160(serializedPubKey)
    addressWitnessPubKeyHash, err := btcutil.NewAddressWitnessPubKeyHash(witnessProg, &chaincfg.MainNetParams)
    if err != nil {
            fmt.Println(err)
            return 
    }

    witnessScript, err := txscript.PayToAddrScript(addressWitnessPubKeyHash)
    if err != nil {
          fmt.Println(err)
          return
    }

    subScript, err := txscript.NewScriptBuilder().AddData(witnessScript).Script()
    if err != nil {
          fmt.Println(err)
          return
    }


    updater, err := psbt.NewUpdater(packet)
    if err != nil {
        fmt.Println(err)
        return
    }


    utxoMap := make(map[wire.OutPoint]*wire.TxOut)
    
    for _, utxo := range UTXOs {
          chainHash, _ := chainhash.NewHashFromStr(utxo.Txid)
          outpoint := wire.NewOutPoint(chainHash, uint32(utxo.Vout))
          value := btcutil.Amount(utxo.Value)
          pkScript, _ := GetPayToAddressScript(utxo.Address)
          txOut := wire.NewTxOut(int64(value), pkScript)
          utxoMap[*outpoint] = txOut
    }

     sigHashes := txscript.NewTxSigHashes(packet.UnsignedTx, &PrevOutputFetcher{Utxos: utxoMap})
     
    for _, index := range inputToSign {
        fmt.Println("Signing input", index)
        sig, err := txscript.RawTxInWitnessSignature(packet.UnsignedTx, sigHashes, index, UTXOs[index].Value, witnessScript, txscript.SigHashAll, wif.PrivKey)
        if err != nil {
            fmt.Println(err)
            return
        }
    
        _, err = updater.Sign(index, sig, serializedPubKey, subScript, witnessScript)
        if err != nil {
            fmt.Println(err)
            return
        }
    }
}

[guggero]

Your error is likely coming from here:

btcd/btcutil/psbt/updater.go

Line 139 in a764afd

if !bytes.Equal(scriptHashScript, scriptPubKey) {

So the redeem script doesn't match, probably it's set wrong in your PSBT.