From 12fad78716134afc178246400d66320089e8ddd5 Mon Sep 17 00:00:00 2001
From: Tomas Martykan <t.martykan@gmail.com>
Date: Wed, 11 Dec 2024 14:41:43 +0100
Subject: [PATCH] feat(connect): improve serializeEthereumTx

---
 .../ethereum/api/ethereumSignTransaction.ts   | 13 +---
 .../src/api/ethereum/ethereumSignTx.ts        | 62 ++++++++++++++-----
 2 files changed, 47 insertions(+), 28 deletions(-)

diff --git a/packages/connect/src/api/ethereum/api/ethereumSignTransaction.ts b/packages/connect/src/api/ethereum/api/ethereumSignTransaction.ts
index 8c43809344a..571e3b79eba 100644
--- a/packages/connect/src/api/ethereum/api/ethereumSignTransaction.ts
+++ b/packages/connect/src/api/ethereum/api/ethereumSignTransaction.ts
@@ -1,7 +1,5 @@
 // origin: https://github.com/trezor/connect/blob/develop/src/js/core/methods/EthereumSignTransaction.js
 
-import { FeeMarketEIP1559TxData, LegacyTxData } from '@ethereumjs/tx';
-
 import { MessagesSchema } from '@trezor/protobuf';
 import { Assert } from '@trezor/schema-utils';
 
@@ -155,16 +153,7 @@ export default class EthereumSignTransaction extends AbstractMethod<
                   definitions,
               );
 
-        const txData = {
-            ...tx,
-            ...signature,
-            type: isLegacy ? 0 : 2, // 0 for legacy, 2 for EIP-1559
-            gasPrice: isLegacy ? tx.gasPrice : undefined,
-            maxFeePerGas: !isLegacy ? tx.maxFeePerGas : undefined,
-            maxPriorityFeePerGas: !isLegacy ? tx.maxPriorityFeePerGas : undefined,
-        } as LegacyTxData | FeeMarketEIP1559TxData;
-
-        const serializedTx = helper.serializeEthereumTx(txData, tx.chainId);
+        const serializedTx = helper.serializeEthereumTx(tx, signature, isLegacy);
 
         return { ...signature, serializedTx };
     }
diff --git a/packages/connect/src/api/ethereum/ethereumSignTx.ts b/packages/connect/src/api/ethereum/ethereumSignTx.ts
index a844bc1d308..b92f48b694c 100644
--- a/packages/connect/src/api/ethereum/ethereumSignTx.ts
+++ b/packages/connect/src/api/ethereum/ethereumSignTx.ts
@@ -7,7 +7,11 @@ import { MessagesSchema } from '@trezor/protobuf';
 
 import { PROTO, ERRORS } from '../../constants';
 import type { TypedCall } from '../../device/DeviceCommands';
-import type { EthereumAccessList } from '../../types/api/ethereum';
+import type {
+    EthereumAccessList,
+    EthereumTransaction,
+    EthereumTransactionEIP1559,
+} from '../../types/api/ethereum';
 import { addHexPrefix, deepTransform } from '../../utils/formatUtils';
 
 const splitString = (str?: string, len?: number) => {
@@ -26,9 +30,9 @@ const processTxRequest = async (
     data?: string,
     chain_id?: number,
 ): Promise<{
-    v: string;
-    r: string;
-    s: string;
+    v: `0x${string}`;
+    r: `0x${string}`;
+    s: `0x${string}`;
 }> => {
     if (!request.data_length) {
         let v = request.signature_v;
@@ -59,24 +63,50 @@ const processTxRequest = async (
 
 const deepHexPrefix = deepTransform(addHexPrefix);
 
-export const serializeEthereumTx = (
-    txData: LegacyTxData | FeeMarketEIP1559TxData,
-    chainId: number,
-) => {
+export const getCommonForChain = (chainId: number) => {
+    // @ethereumjs/tx directly supported chains
+    if (Common.isSupportedChainId(BigInt(chainId))) return new Common({ chain: chainId });
+
     // @ethereumjs/tx doesn't support ETC (chain 61) by default
     // and it needs to be declared as custom chain
     // see: https://github.com/ethereumjs/ethereumjs-tx/blob/master/examples/custom-chain-tx.ts
-    const txOptions =
-        chainId === 61
+    if (chainId === 61)
+        return Common.custom(
+            { name: 'ethereum-classic', networkId: 1, chainId: 61 },
+            { baseChain: Chain.Mainnet, hardfork: Hardfork.Petersburg },
+        );
+
+    // other chains
+    return Common.custom({ chainId });
+};
+
+export const serializeEthereumTx = (
+    tx: EthereumTransactionEIP1559 | EthereumTransaction,
+    signature: { v: `0x${string}`; r: `0x${string}`; s: `0x${string}` },
+    isLegacy: boolean,
+) => {
+    const txData = deepHexPrefix({
+        ...tx,
+        ...signature,
+        type: isLegacy ? 0 : 2, // 0 for legacy, 2 for EIP-1559
+        ...(isLegacy
             ? {
-                  common: Common.custom(
-                      { name: 'ethereum-classic', networkId: 1, chainId: 61 },
-                      { baseChain: Chain.Mainnet, hardfork: Hardfork.Petersburg },
-                  ),
+                  gasPrice: tx.gasPrice,
+                  maxFeePerGas: undefined,
+                  maxPriorityFeePerGas: undefined,
               }
-            : { chain: chainId };
+            : {
+                  gasPrice: undefined,
+                  maxFeePerGas: tx.maxFeePerGas,
+                  maxPriorityFeePerGas: tx.maxPriorityFeePerGas,
+              }),
+    }) satisfies LegacyTxData | FeeMarketEIP1559TxData;
+
+    const txOptions = {
+        common: getCommonForChain(tx.chainId),
+    };
 
-    const ethTx = TransactionFactory.fromTxData(deepHexPrefix(txData), txOptions);
+    const ethTx = TransactionFactory.fromTxData(txData, txOptions);
 
     return `0x${Buffer.from(ethTx.serialize()).toString('hex')}`;
 };