From c9c19bcd8a1e5ecc71357ba06ac19fee984dac5a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20Negovanovi=C4=87?=
 <93934272+Stefan-Ethernal@users.noreply.github.com>
Date: Thu, 10 Aug 2023 13:38:23 +0200
Subject: [PATCH] Fix hash calculation for dynamic fee and access list
 transactions (#253)

* Simplify and make signing more readable

* Include Dynamic fee transactions signing in the test

* Hash using provided chain id instead the one from transaction

* Change transaction type to uint8 data type
---
 structs.go            |  2 +-
 wallet/signer.go      | 20 ++++++++------------
 wallet/signer_test.go | 19 +++++++++++++------
 3 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/structs.go b/structs.go
index f8a24c13..699d5899 100644
--- a/structs.go
+++ b/structs.go
@@ -164,7 +164,7 @@ func (b *Block) Copy() *Block {
 	return bb
 }
 
-type TransactionType int
+type TransactionType uint8
 
 const (
 	TransactionLegacy TransactionType = 0
diff --git a/wallet/signer.go b/wallet/signer.go
index 0d12a56a..dad25ec7 100644
--- a/wallet/signer.go
+++ b/wallet/signer.go
@@ -75,12 +75,13 @@ func (e *EIP1155Signer) SignTx(tx *ethgo.Transaction, key ethgo.Key) (*ethgo.Tra
 
 func signHash(tx *ethgo.Transaction, chainID uint64) []byte {
 	a := fastrlp.DefaultArenaPool.Get()
+	defer fastrlp.DefaultArenaPool.Put(a)
 
 	v := a.NewArray()
 
-	if tx.Type != 0 {
+	if tx.Type != ethgo.TransactionLegacy {
 		// either dynamic and access type
-		v.Set(a.NewBigInt(tx.ChainID))
+		v.Set(a.NewBigInt(new(big.Int).SetUint64(chainID)))
 	}
 
 	v.Set(a.NewUint(tx.Nonce))
@@ -103,7 +104,7 @@ func signHash(tx *ethgo.Transaction, chainID uint64) []byte {
 	v.Set(a.NewBigInt(tx.Value))
 	v.Set(a.NewCopyBytes(tx.Input))
 
-	if tx.Type != 0 {
+	if tx.Type != ethgo.TransactionLegacy {
 		// either dynamic and access type
 		accessList, err := tx.AccessList.MarshalRLPWith(a)
 		if err != nil {
@@ -113,7 +114,7 @@ func signHash(tx *ethgo.Transaction, chainID uint64) []byte {
 	}
 
 	// EIP155
-	if chainID != 0 && tx.Type == 0 {
+	if chainID != 0 && tx.Type == ethgo.TransactionLegacy {
 		v.Set(a.NewUint(chainID))
 		v.Set(a.NewUint(0))
 		v.Set(a.NewUint(0))
@@ -122,15 +123,10 @@ func signHash(tx *ethgo.Transaction, chainID uint64) []byte {
 	dst := v.MarshalTo(nil)
 
 	// append the tx type byte
-	if tx.Type == ethgo.TransactionAccessList {
-		dst = append([]byte{0x1}, dst...)
-	} else if tx.Type == ethgo.TransactionDynamicFee {
-		dst = append([]byte{0x2}, dst...)
+	if tx.Type != ethgo.TransactionLegacy {
+		dst = append([]byte{byte(tx.Type)}, dst...)
 	}
-
-	hash := ethgo.Keccak256(dst)
-	fastrlp.DefaultArenaPool.Put(a)
-	return hash
+	return ethgo.Keccak256(dst)
 }
 
 func encodeSignature(R, S []byte, V byte) ([]byte, error) {
diff --git a/wallet/signer_test.go b/wallet/signer_test.go
index dcff5fa4..dde31c44 100644
--- a/wallet/signer_test.go
+++ b/wallet/signer_test.go
@@ -12,8 +12,6 @@ import (
 
 func TestSigner_SignAndRecover(t *testing.T) {
 	rapid.Check(t, func(t *rapid.T) {
-		istyped := rapid.Bool().Draw(t, "istyped")
-
 		// fill in common types for a transaction
 		txn := &ethgo.Transaction{}
 
@@ -22,15 +20,24 @@ func TestSigner_SignAndRecover(t *testing.T) {
 			txn.To = &to
 		}
 
+		txType := rapid.IntRange(0, 2).Draw(t, "tx type")
+
 		// fill in specific fields depending on the type
 		// of the transaction.
-		if istyped {
-			txn.Type = ethgo.TransactionAccessList
+		txn.Type = ethgo.TransactionType(txType)
+		if txn.Type == ethgo.TransactionDynamicFee {
+			maxFeePerGas := rapid.Int64Range(1, 1000000000).Draw(t, "maxFeePerGas")
+			txn.MaxFeePerGas = big.NewInt(maxFeePerGas)
+			maxPriorityFeePerGas := rapid.Int64Range(1, 1000000000).Draw(t, "maxPriorityFeePerGas")
+			txn.MaxPriorityFeePerGas = big.NewInt(maxPriorityFeePerGas)
+		} else {
+			gasPrice := rapid.Uint64Range(1, 1000000000).Draw(t, "gasPrice")
+			txn.GasPrice = gasPrice
 		}
 
 		// signer is from a random chain
-		chainid := rapid.Uint64().Draw(t, "chainid")
-		signer := NewEIP155Signer(chainid)
+		chainId := rapid.Uint64().Draw(t, "chainId")
+		signer := NewEIP155Signer(chainId)
 
 		key, err := GenerateKey()
 		require.NoError(t, err)