From 13221de896b81e81271187314b4022ef5b4d987b Mon Sep 17 00:00:00 2001
From: Lukasz Rozmej <lukasz.rozmej@gmail.com>
Date: Mon, 17 May 2021 21:45:02 +0200
Subject: [PATCH] Validate ChainId on non-legacy transactions (#3061)

---
 .../Validators/TxValidatorTests.cs            | 22 ++++++++++++
 .../Validators/TxValidator.cs                 | 34 ++++++++++++++++---
 2 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/src/Nethermind/Nethermind.Blockchain.Test/Validators/TxValidatorTests.cs b/src/Nethermind/Nethermind.Blockchain.Test/Validators/TxValidatorTests.cs
index 4906a41f0d3..df6401fb10a 100644
--- a/src/Nethermind/Nethermind.Blockchain.Test/Validators/TxValidatorTests.cs
+++ b/src/Nethermind/Nethermind.Blockchain.Test/Validators/TxValidatorTests.cs
@@ -176,5 +176,27 @@ public bool Before_eip_1559_has_to_be_legacy_or_access_list_tx(TxType txType, bo
             IReleaseSpec releaseSpec = new ReleaseSpec() {IsEip2930Enabled = eip2930, IsEip1559Enabled = eip1559};
             return txValidator.IsWellFormed(tx, releaseSpec);
         }
+        
+        
+        [TestCase(TxType.Legacy, ExpectedResult = true)]
+        [TestCase(TxType.AccessList, ExpectedResult = false)]
+        [TestCase(TxType.EIP1559, ExpectedResult = false)]
+        public bool Chain_Id_required_for_non_legacy_transactions_after_Berlin(TxType txType)
+        {
+            byte[] sigData = new byte[65];
+            sigData[31] = 1; // correct r
+            sigData[63] = 1; // correct s
+            sigData[64] = 38;
+            Signature signature = new Signature(sigData);
+            Transaction tx = Build.A.Transaction
+                .WithType(txType > TxType.AccessList ? TxType.Legacy : txType)
+                .WithAccessList(txType == TxType.AccessList ? new AccessList(new Dictionary<Address, IReadOnlySet<UInt256>>()) : null)
+                .WithSignature(signature).TestObject;
+
+            tx.Type = txType;
+            
+            TxValidator txValidator = new TxValidator(ChainId.Mainnet);
+            return txValidator.IsWellFormed(tx, Berlin.Instance);
+        }
     }
 }
diff --git a/src/Nethermind/Nethermind.Blockchain/Validators/TxValidator.cs b/src/Nethermind/Nethermind.Blockchain/Validators/TxValidator.cs
index 07da1282fc7..a5ed01066f9 100644
--- a/src/Nethermind/Nethermind.Blockchain/Validators/TxValidator.cs
+++ b/src/Nethermind/Nethermind.Blockchain/Validators/TxValidator.cs
@@ -14,6 +14,7 @@
 //  You should have received a copy of the GNU Lesser General Public License
 //  along with the Nethermind. If not, see <http://www.gnu.org/licenses/>.
 
+using System;
 using System.Numerics;
 using Nethermind.Core;
 using Nethermind.Core.Crypto;
@@ -49,16 +50,39 @@ public bool IsWellFormed(Transaction transaction, IReleaseSpec releaseSpec)
                    transaction.GasLimit >= IntrinsicGasCalculator.Calculate(transaction, releaseSpec) &&
                    /* if it is a call or a transfer then we require the 'To' field to have a value
                       while for an init it will be empty */
-                   ValidateSignature(transaction.Signature, releaseSpec);
+                   ValidateSignature(transaction.Signature, releaseSpec) &&
+                   ValidateChainId(transaction);
         }
 
         private bool ValidateTxType(Transaction transaction, IReleaseSpec releaseSpec)
         {
-            return transaction.Type == TxType.Legacy || 
-                   (transaction.Type == TxType.AccessList && releaseSpec.UseTxAccessLists) ||
-                   (transaction.Type == TxType.EIP1559 && releaseSpec.IsEip1559Enabled);
+            switch (transaction.Type)
+            {
+                case TxType.Legacy:
+                    return true;
+                case TxType.AccessList:
+                    return releaseSpec.UseTxAccessLists;
+                case TxType.EIP1559:
+                    return releaseSpec.IsEip1559Enabled;
+                default:
+                    return false;
+            }
         }
-
+        
+        private bool ValidateChainId(Transaction transaction)
+        {
+            switch (transaction.Type)
+            {
+                case TxType.Legacy:
+                    return true;
+                case TxType.AccessList:
+                case TxType.EIP1559:
+                    return transaction.ChainId == _chainIdValue;
+                default:
+                    return false;
+            }
+        }
+        
         private bool ValidateSignature(Signature signature, IReleaseSpec spec)
         {
             BigInteger sValue = signature.SAsSpan.ToUnsignedBigInteger();