From 43871c6141652ba0ee5f7f0fe5575e31c47c1806 Mon Sep 17 00:00:00 2001
From: ChronosX88 <chronosx88@gmail.com>
Date: Thu, 27 May 2021 00:29:37 +0300
Subject: [PATCH] Add validation of tx hash when syncing

---
 blockchain/sync/sync_mgr.go     | 3 +++
 blockchain/types/transaction.go | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/blockchain/sync/sync_mgr.go b/blockchain/sync/sync_mgr.go
index 91c2f8e..2a6cbef 100644
--- a/blockchain/sync/sync_mgr.go
+++ b/blockchain/sync/sync_mgr.go
@@ -158,6 +158,9 @@ func (sm *syncManager) processReceivedBlock(block types2.Block) error {
 		if !txProofVerified {
 			return fmt.Errorf("transaction doesn't present in block hash merkle tree")
 		}
+		if !tx.ValidateHash() {
+			return fmt.Errorf("transaction hash is invalid")
+		}
 	}
 
 	err = sm.blockPool.StoreBlock(&block)
diff --git a/blockchain/types/transaction.go b/blockchain/types/transaction.go
index 3be0e0d..abb4c6d 100644
--- a/blockchain/types/transaction.go
+++ b/blockchain/types/transaction.go
@@ -1,6 +1,7 @@
 package types
 
 import (
+	"bytes"
 	"encoding/hex"
 	"fmt"
 	"time"
@@ -27,3 +28,11 @@ func CreateTransaction(data []byte) *Transaction {
 		Data:      data,
 	}
 }
+
+func (tx *Transaction) ValidateHash() bool {
+	h := crypto.Keccak256([]byte(fmt.Sprintf("%d_%s", tx.Timestamp.Unix(), tx.Hash)))
+	if bytes.Compare(h, tx.Hash) != 0 {
+		return false
+	}
+	return true
+}