feat!: limit the max tx size to 2 MiB

app/ante/ante.go

@@ -32,6 +32,8 @@ func NewAnteHandler(
 		// Set up the context with a gas meter.
 		// Must be called before gas consumption occurs in any other decorator.
 		ante.NewSetUpContextDecorator(),
+		// Ensure the tx is not larger than the configured threshold.
+		NewMaxTxSizeDecorator(),
 		// Ensure the tx does not contain any extension options.
 		ante.NewExtensionOptionsDecorator(nil),
 		// Ensure the tx passes ValidateBasic.

app/ante/max_tx_size.go

@@ -0,0 +1,27 @@
+package ante
+
+import (
+	"github.com/celestiaorg/celestia-app/v3/pkg/appconsts"
+	v3 "github.com/celestiaorg/celestia-app/v3/pkg/appconsts/v3"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+)
+
+// MaxTxSizeDecorator ensures that a tx can not be larger than
+// application's configured versioned constant.
+type MaxTxSizeDecorator struct{}
+
+func NewMaxTxSizeDecorator() MaxTxSizeDecorator {
+	return MaxTxSizeDecorator{}
+}
+
+// AnteHandle implements the AnteHandler interface. It ensures that tx size is under application's configured threshold.
+func (d MaxTxSizeDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (sdk.Context, error) {
+	// Tx size rule applies to app versions v3 and onwards.
+	if ctx.BlockHeader().Version.App >= v3.Version {
+		if len(ctx.TxBytes()) >= appconsts.MaxTxBytes(ctx.BlockHeader().Version.App) {
+			return ctx, sdkerrors.ErrTxTooLarge
+		}
+	}
+	return next(ctx, tx, simulate)
+}

app/ante/max_tx_size_test.go

@@ -0,0 +1,72 @@
+package ante_test
+
+import (
+	"testing"
+
+	"github.com/celestiaorg/celestia-app/v3/app/ante"
+	v2 "github.com/celestiaorg/celestia-app/v3/pkg/appconsts/v2"
+	v3 "github.com/celestiaorg/celestia-app/v3/pkg/appconsts/v3"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	"github.com/stretchr/testify/require"
+	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
+	version "github.com/tendermint/tendermint/proto/tendermint/version"
+)
+
+func TestMaxTxSizeDecorator(t *testing.T) {
+	decorator := ante.NewMaxTxSizeDecorator()
+	anteHandler := sdk.ChainAnteDecorators(decorator)
+
+	testCases := []struct {
+		name        string
+		txSize      int
+		expectError bool
+		appVersion  uint64
+	}{
+		{
+			name:        "good tx; under max tx bytes threshold",
+			txSize:      v3.MaxTxBytes - 1,
+			appVersion:  v3.Version,
+			expectError: false,
+		},
+		{
+			name:        "bad tx; over max tx bytes threshold",
+			txSize:      v3.MaxTxBytes + 1,
+			appVersion:  v3.Version,
+			expectError: true,
+		},
+		{
+			name:        "bad tx; equal to max tx bytes threshold",
+			txSize:      v3.MaxTxBytes,
+			appVersion:  v3.Version,
+			expectError: true,
+		},
+		{
+			name:        "only applies to v3 and above",
+			txSize:      v3.MaxTxBytes,
+			appVersion:  v2.Version,
+			expectError: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			ctx := sdk.NewContext(nil, tmproto.Header{
+				Version: version.Consensus{
+					App: tc.appVersion,
+				},
+			}, false, nil)
+
+			txBytes := make([]byte, tc.txSize)
+
+			ctx = ctx.WithTxBytes(txBytes)
+			_, err := anteHandler(ctx, nil, false)
+			if tc.expectError {
+				require.Error(t, err)
+				require.Contains(t, err.Error(), sdkerrors.ErrTxTooLarge.Error())
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}

pkg/appconsts/v3/app_consts.go

@@ -6,4 +6,5 @@ const (
 	SubtreeRootThreshold int    = 64
 	TxSizeCostPerByte    uint64 = 10
 	GasPerBlobByte       uint32 = 8
+	MaxTxBytes           int    = 2097152 // 2 MiB in bytes
 )

pkg/appconsts/versioned_consts.go

@@ -42,6 +42,10 @@ func GasPerBlobByte(_ uint64) uint32 {
 	return v3.GasPerBlobByte
 }
 
+func MaxTxBytes(_ uint64) int {
+	return v3.MaxTxBytes
+}
+
 var (
 	DefaultSubtreeRootThreshold = SubtreeRootThreshold(LatestVersion)
 	DefaultSquareSizeUpperBound = SquareSizeUpperBound(LatestVersion)

pkg/appconsts/versioned_consts_test.go

@@ -66,6 +66,12 @@ func TestVersionedConsts(t *testing.T) {
 			expectedConstant: v3.GasPerBlobByte,
 			got:              appconsts.GasPerBlobByte(v3.Version),
 		},
+		{
+			name:             "MaxTxBytes v3",
+			version:          v3.Version,
+			expectedConstant: v3.MaxTxBytes,
+			got:              appconsts.MaxTxBytes(v3.Version),
+		},
 	}
 
 	for _, tc := range testCases {

specs/src/ante_handler_v3.md

@@ -3,6 +3,7 @@
 The AnteHandler chains together several decorators to ensure the following criteria are met for app version 3:
 
 - The tx does not contain any messages that are unsupported by the current app version. See `MsgVersioningGateKeeper`.
+- The tx size is not larger than the application's configured versioned constant MaxTxBytes.
 - The tx does not contain any [extension options](https://github.com/cosmos/cosmos-sdk/blob/22c28366466e64ebf0df1ce5bec8b1130523552c/proto/cosmos/tx/v1beta1/tx.proto#L119-L122).
 - The tx passes `ValidateBasic()`.
 - The tx's [timeout_height](https://github.com/cosmos/cosmos-sdk/blob/22c28366466e64ebf0df1ce5bec8b1130523552c/proto/cosmos/tx/v1beta1/tx.proto#L115-L117) has not been reached if one is specified.