From 1b6970a44255d5cdb4d7562af19e197b772ffc71 Mon Sep 17 00:00:00 2001
From: Josh Klopfenstein <git@joshklop.com>
Date: Thu, 5 Dec 2024 15:13:49 -0600
Subject: [PATCH] Only allow deposit messages from the op node

The important change is in helpers/ante.go.

Before, we were only blocking deposit transactions from the Monomer mempool.
This meant that standard auth txs could contain deposit messages, minting arbitrary amounts of eth.
We fix this by checking for deposit messages in all transactions in helpers/ante.go.
---
 mempool/mempool.go          |  8 --------
 mempool/mempool_test.go     | 14 --------------
 x/rollup/tx/helpers/ante.go | 31 +++++++++++++++++++------------
 3 files changed, 19 insertions(+), 34 deletions(-)

diff --git a/mempool/mempool.go b/mempool/mempool.go
index e7cbb28d..d401f37f 100644
--- a/mempool/mempool.go
+++ b/mempool/mempool.go
@@ -8,7 +8,6 @@ import (
 
 	comettypes "github.com/cometbft/cometbft/types"
 	dbm "github.com/cosmos/cosmos-db"
-	"github.com/polymerdao/monomer"
 	"github.com/polymerdao/monomer/utils"
 )
 
@@ -39,13 +38,6 @@ func (p *Pool) Enqueue(userTxn comettypes.Tx) (err error) {
 	// Unfortunately, comet's DB interface doesn't support it.
 	// Moving to a different DB interface is left for future work.
 
-	// Attempt to adapt the Cosmos transaction to an Ethereum deposit transaction.
-	// If the adaptation succeeds, it indicates that the
-	// user transaction is a deposit transaction, which is not allowed in the pool.
-	if _, err := monomer.GetDepositTxs(userTxn); err == nil {
-		return errors.New("deposit txs are not allowed in the pool")
-	}
-
 	batch := p.db.NewBatch()
 	defer func() {
 		err = utils.WrapCloseErr(err, batch)
diff --git a/mempool/mempool_test.go b/mempool/mempool_test.go
index deadac62..e3bc57be 100644
--- a/mempool/mempool_test.go
+++ b/mempool/mempool_test.go
@@ -4,8 +4,6 @@ import (
 	"testing"
 
 	comettypes "github.com/cometbft/cometbft/types"
-	"github.com/ethereum/go-ethereum/common/hexutil"
-	"github.com/polymerdao/monomer"
 	"github.com/polymerdao/monomer/mempool"
 	"github.com/polymerdao/monomer/testutils"
 	"github.com/stretchr/testify/assert"
@@ -24,18 +22,6 @@ func TestMempool(t *testing.T) {
 		require.Error(t, err)
 	})
 
-	t.Run("deposit transaction", func(t *testing.T) {
-		l1AttributesTx, depositTx, _ := testutils.GenerateEthTxs(t)
-		l1AttributesTxBytes, err := l1AttributesTx.MarshalBinary()
-		require.NoError(t, err)
-		depositTxBytes, err := depositTx.MarshalBinary()
-		require.NoError(t, err)
-
-		cosmosTxs, err := monomer.AdaptPayloadTxsToCosmosTxs([]hexutil.Bytes{l1AttributesTxBytes, depositTxBytes})
-		require.NoError(t, err)
-		require.ErrorContains(t, pool.Enqueue(cosmosTxs[0]), "deposit txs are not allowed in the pool")
-	})
-
 	// enqueue multiple to empty
 	for i := byte(0); i < 3; i++ {
 		require.NoError(t, pool.Enqueue(comettypes.Tx([]byte{i})))
diff --git a/x/rollup/tx/helpers/ante.go b/x/rollup/tx/helpers/ante.go
index eb1a20ab..ca8b9ce6 100644
--- a/x/rollup/tx/helpers/ante.go
+++ b/x/rollup/tx/helpers/ante.go
@@ -1,6 +1,7 @@
 package helpers
 
 import (
+	"errors"
 	"fmt"
 
 	sdktypes "github.com/cosmos/cosmos-sdk/types"
@@ -35,22 +36,28 @@ func (a *AnteHandler) AnteHandle(
 	tx sdktypes.Tx,
 	simulate bool,
 ) (sdktypes.Context, error) {
-	switch tx.(type) {
-	case *rolluptypes.DepositsTx:
+	if _, ok := tx.(*rolluptypes.DepositsTx); ok {
 		newCtx, err := rolluptx.DepositAnteHandler(ctx, tx, simulate)
 		if err != nil {
 			return newCtx, fmt.Errorf("deposit ante handle: %v", err)
 		}
-		return newCtx, err
-	default: // Unfortunately, the Cosmos SDK does not export its default tx type.
-		newCtx, err := a.authAnteHandler(ctx, tx, simulate)
-		if err != nil {
-			return newCtx, fmt.Errorf("auth ante handle: %v", err)
-		}
-		newCtx, err = rolluptx.L1DataAnteHandler(newCtx, tx, a.rollupKeeper)
-		if err != nil {
-			return newCtx, fmt.Errorf("l1 data ante handle: %v", err)
-		}
 		return newCtx, nil
 	}
+
+	for _, msg := range tx.GetMsgs() {
+		if _, ok := msg.(rolluptypes.DepositMsg); ok {
+			return ctx, errors.New("transaction contains deposit message")
+		}
+	}
+
+	// need the tx decoder
+	newCtx, err := a.authAnteHandler(ctx, tx, simulate)
+	if err != nil {
+		return newCtx, fmt.Errorf("auth ante handle: %v", err)
+	}
+	newCtx, err = rolluptx.L1DataAnteHandler(newCtx, tx, a.rollupKeeper)
+	if err != nil {
+		return newCtx, fmt.Errorf("l1 data ante handle: %v", err)
+	}
+	return newCtx, nil
 }