From 0bcd84b3b430741b2d077c6fbb2f80a07f9f9d88 Mon Sep 17 00:00:00 2001
From: tchardin <tdotchardin@gmail.com>
Date: Tue, 27 Feb 2024 13:15:50 -0600
Subject: [PATCH] feat: skip oversized inputs

---
 op-batcher/batcher/service.go                 |  5 ++
 op-node/rollup/derive/plasma_data_source.go   |  6 ++
 .../rollup/derive/plasma_data_source_test.go  | 87 +++++++++++++++++++
 op-plasma/params.go                           |  6 ++
 4 files changed, 104 insertions(+)
 create mode 100644 op-plasma/params.go

diff --git a/op-batcher/batcher/service.go b/op-batcher/batcher/service.go
index c5a5cd0c3096..0923db861caf 100644
--- a/op-batcher/batcher/service.go
+++ b/op-batcher/batcher/service.go
@@ -205,6 +205,11 @@ func (bs *BatcherService) initChannelConfig(cfg *CLIConfig) error {
 	default:
 		return fmt.Errorf("unknown data availability type: %v", cfg.DataAvailabilityType)
 	}
+
+	if bs.UsePlasma && bs.ChannelConfig.MaxFrameSize > plasma.MaxInputSize {
+		return fmt.Errorf("max frame size %d exceeds plasma max input size %d", bs.ChannelConfig.MaxFrameSize, plasma.MaxInputSize)
+	}
+
 	bs.ChannelConfig.MaxFrameSize-- // subtract 1 byte for version
 
 	if bs.UseBlobs && !bs.RollupConfig.IsEcotone(uint64(time.Now().Unix())) {
diff --git a/op-node/rollup/derive/plasma_data_source.go b/op-node/rollup/derive/plasma_data_source.go
index 15a7648cf1ee..ee0ac0079961 100644
--- a/op-node/rollup/derive/plasma_data_source.go
+++ b/op-node/rollup/derive/plasma_data_source.go
@@ -69,6 +69,12 @@ func (s *PlasmaDataSource) Next(ctx context.Context) (eth.Data, error) {
 		// return temporary error so we can keep retrying.
 		return nil, NewTemporaryError(fmt.Errorf("failed to fetch input data with comm %x from da service: %w", s.comm, err))
 	}
+	// inputs are limited to a max size to ensure they can be challenged in the DA contract.
+	if len(data) > plasma.MaxInputSize {
+		s.log.Warn("input data exceeds max size", "size", len(data), "max", plasma.MaxInputSize)
+		s.comm = nil
+		return s.Next(ctx)
+	}
 	// reset the commitment so we can fetch the next one from the source at the next iteration.
 	s.comm = nil
 	return data, nil
diff --git a/op-node/rollup/derive/plasma_data_source_test.go b/op-node/rollup/derive/plasma_data_source_test.go
index 4db21f9a86eb..28bd72b6f031 100644
--- a/op-node/rollup/derive/plasma_data_source_test.go
+++ b/op-node/rollup/derive/plasma_data_source_test.go
@@ -369,3 +369,90 @@ func TestPlasmaDataSourceStall(t *testing.T) {
 
 	l1F.AssertExpectations(t)
 }
+
+func TestPlasmaDataSourceOversizedInput(t *testing.T) {
+	logger := testlog.Logger(t, log.LevelDebug)
+	ctx := context.Background()
+
+	rng := rand.New(rand.NewSource(1234))
+
+	l1F := &testutils.MockL1Source{}
+
+	storage := plasma.NewMockDAClient(logger)
+
+	pcfg := plasma.Config{
+		ChallengeWindow: 90, ResolveWindow: 90,
+	}
+
+	da := plasma.NewPlasmaDAWithStorage(logger, pcfg, storage, l1F, &plasma.NoopMetrics{})
+
+	// Create rollup genesis and config
+	l1Time := uint64(2)
+	refA := testutils.RandomBlockRef(rng)
+	refA.Number = 1
+	l1Refs := []eth.L1BlockRef{refA}
+	refA0 := eth.L2BlockRef{
+		Hash:           testutils.RandomHash(rng),
+		Number:         0,
+		ParentHash:     common.Hash{},
+		Time:           refA.Time,
+		L1Origin:       refA.ID(),
+		SequenceNumber: 0,
+	}
+	batcherPriv := testutils.RandomKey()
+	batcherAddr := crypto.PubkeyToAddress(batcherPriv.PublicKey)
+	batcherInbox := common.Address{42}
+	cfg := &rollup.Config{
+		Genesis: rollup.Genesis{
+			L1:     refA.ID(),
+			L2:     refA0.ID(),
+			L2Time: refA0.Time,
+		},
+		BlockTime:          1,
+		SeqWindowSize:      20,
+		BatchInboxAddress:  batcherInbox,
+		DAChallengeAddress: common.Address{43},
+	}
+
+	signer := cfg.L1Signer()
+
+	factory := NewDataSourceFactory(logger, cfg, l1F, nil, da)
+
+	parent := l1Refs[0]
+	// create a new mock l1 ref
+	ref := eth.L1BlockRef{
+		Hash:       testutils.RandomHash(rng),
+		Number:     parent.Number + 1,
+		ParentHash: parent.Hash,
+		Time:       parent.Time + l1Time,
+	}
+	l1F.ExpectFetchReceipts(ref.Hash, nil, types.Receipts{}, nil)
+	// mock input commitments in l1 transactions with an oversized input
+	input := testutils.RandomData(rng, plasma.MaxInputSize+1)
+	comm, _ := storage.SetInput(ctx, input)
+
+	tx, err := types.SignNewTx(batcherPriv, signer, &types.DynamicFeeTx{
+		ChainID:   signer.ChainID(),
+		Nonce:     0,
+		GasTipCap: big.NewInt(2 * params.GWei),
+		GasFeeCap: big.NewInt(30 * params.GWei),
+		Gas:       100_000,
+		To:        &batcherInbox,
+		Value:     big.NewInt(int64(0)),
+		Data:      comm,
+	})
+	require.NoError(t, err)
+
+	txs := []*types.Transaction{tx}
+
+	l1F.ExpectInfoAndTxsByHash(ref.Hash, testutils.RandomBlockInfo(rng), txs, nil)
+
+	src, err := factory.OpenData(ctx, ref, batcherAddr)
+	require.NoError(t, err)
+
+	// data is skipped so should return an EOF
+	_, err = src.Next(ctx)
+	require.ErrorIs(t, err, io.EOF)
+
+	l1F.AssertExpectations(t)
+}
diff --git a/op-plasma/params.go b/op-plasma/params.go
new file mode 100644
index 000000000000..3377d981cd00
--- /dev/null
+++ b/op-plasma/params.go
@@ -0,0 +1,6 @@
+package plasma
+
+// Max input size ensures the canonical chain cannot include input batches too large to
+// challenge in the Data Availability Challenge contract. Value in number of bytes.
+// This value can only be changed in a hard fork.
+const MaxInputSize = 130672