Add RejectExtensionOptionsDecorator (#6988)

* Add RejectExtensionOptionsDecorator

* Fix error code

* Fix lint

* Add ExtensionOptionsTxBuilder

* Add tests

* Add tests

* Update tests

* Docs

Co-authored-by: sahith-narahari <sahithnarahari@gmail.com>
Co-authored-by: Alexander Bezobchuk <alexanderbez@users.noreply.github.com>

types/errors/errors.go

@@ -110,6 +110,9 @@ var (
 	// explicitly set timeout height.
 	ErrTxTimeoutHeight = Register(RootCodespace, 30, "tx timeout height")
 
+	// ErrUnknownExtensionOptions defines an error for unknown extension options.
+	ErrUnknownExtensionOptions = Register(RootCodespace, 31, "unknown extension options")
+
 	// ErrPanic is only set when we recover from a panic, so we know to
 	// redact potentially sensitive system info
 	ErrPanic = Register(UndefinedCodespace, 111222, "panic")

x/auth/ante/ante.go

@@ -16,6 +16,7 @@ func NewAnteHandler(
 ) sdk.AnteHandler {
 	return sdk.ChainAnteDecorators(
 		NewSetUpContextDecorator(), // outermost AnteDecorator. SetUpContext must be called first
+		NewRejectExtensionOptionsDecorator(),
 		NewMempoolFeeDecorator(),
 		NewValidateBasicDecorator(),
 		TxTimeoutHeightDecorator{},

x/auth/ante/ext.go

@@ -0,0 +1,36 @@
+package ante
+
+import (
+	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
+	"github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+)
+
+type HasExtensionOptionsTx interface {
+	GetExtensionOptions() []*codectypes.Any
+	GetNonCriticalExtensionOptions() []*codectypes.Any
+}
+
+// RejectExtensionOptionsDecorator is an AnteDecorator that rejects all extension
+// options which can optionally be included in protobuf transactions. Users that
+// need extension options should create a custom AnteHandler chain that handles
+// needed extension options properly and rejects unknown ones.
+type RejectExtensionOptionsDecorator struct{}
+
+// NewRejectExtensionOptionsDecorator creates a new RejectExtensionOptionsDecorator
+func NewRejectExtensionOptionsDecorator() RejectExtensionOptionsDecorator {
+	return RejectExtensionOptionsDecorator{}
+}
+
+var _ types.AnteDecorator = RejectExtensionOptionsDecorator{}
+
+// AnteHandle implements the AnteDecorator.AnteHandle method
+func (r RejectExtensionOptionsDecorator) AnteHandle(ctx types.Context, tx types.Tx, simulate bool, next types.AnteHandler) (newCtx types.Context, err error) {
+	if hasExtOptsTx, ok := tx.(HasExtensionOptionsTx); ok {
+		if len(hasExtOptsTx.GetExtensionOptions()) != 0 {
+			return ctx, sdkerrors.ErrUnknownExtensionOptions
+		}
+	}
+
+	return next(ctx, tx, simulate)
+}

x/auth/ante/ext_test.go

@@ -0,0 +1,36 @@
+package ante_test
+
+import (
+	"github.com/cosmos/cosmos-sdk/codec/types"
+	"github.com/cosmos/cosmos-sdk/testutil/testdata"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/auth/ante"
+	"github.com/cosmos/cosmos-sdk/x/auth/tx"
+)
+
+func (suite *AnteTestSuite) TestRejectExtensionOptionsDecorator() {
+	suite.SetupTest(true) // setup
+	suite.txBuilder = suite.clientCtx.TxConfig.NewTxBuilder()
+
+	reod := ante.NewRejectExtensionOptionsDecorator()
+	antehandler := sdk.ChainAnteDecorators(reod)
+
+	// no extension options should not trigger an error
+	theTx := suite.txBuilder.GetTx()
+	_, err := antehandler(suite.ctx, theTx, false)
+	suite.Require().NoError(err)
+
+	extOptsTxBldr, ok := suite.txBuilder.(tx.ExtensionOptionsTxBuilder)
+	if !ok {
+		// if we can't set extension options, this decorator doesn't apply and we're done
+		return
+	}
+
+	// setting any extension option should cause an error
+	any, err := types.NewAnyWithValue(testdata.NewTestMsg())
+	suite.Require().NoError(err)
+	extOptsTxBldr.SetExtensionOptions(any)
+	theTx = suite.txBuilder.GetTx()
+	_, err = antehandler(suite.ctx, theTx, false)
+	suite.Require().EqualError(err, "unknown extension options")
+}

x/auth/tx/builder.go

@@ -14,6 +14,7 @@ import (
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/tx"
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
+	"github.com/cosmos/cosmos-sdk/x/auth/ante"
 	authsigning "github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
 
@@ -38,10 +39,19 @@ type builder struct {
 }
 
 var (
-	_ authsigning.Tx   = &builder{}
-	_ client.TxBuilder = &builder{}
+	_ authsigning.Tx             = &builder{}
+	_ client.TxBuilder           = &builder{}
+	_ ante.HasExtensionOptionsTx = &builder{}
+	_ ExtensionOptionsTxBuilder  = &builder{}
 )
 
+type ExtensionOptionsTxBuilder interface {
+	client.TxBuilder
+
+	SetExtensionOptions(...*codectypes.Any)
+	SetNonCriticalExtensionOptions(...*codectypes.Any)
+}
+
 func newBuilder(pubkeyCodec types.PublicKeyCodec) *builder {
 	return &builder{
 		tx: &tx.Tx{
@@ -391,3 +401,21 @@ func (t *builder) setSignatures(sigs [][]byte) {
 func (t *builder) GetTx() authsigning.Tx {
 	return t
 }
+
+func (t *builder) GetExtensionOptions() []*codectypes.Any {
+	return t.tx.Body.ExtensionOptions
+}
+
+func (t *builder) GetNonCriticalExtensionOptions() []*codectypes.Any {
+	return t.tx.Body.NonCriticalExtensionOptions
+}
+
+func (t *builder) SetExtensionOptions(extOpts ...*codectypes.Any) {
+	t.tx.Body.ExtensionOptions = extOpts
+	t.bodyBz = nil
+}
+
+func (t *builder) SetNonCriticalExtensionOptions(extOpts ...*codectypes.Any) {
+	t.tx.Body.NonCriticalExtensionOptions = extOpts
+	t.bodyBz = nil
+}

x/auth/tx/builder_test.go

@@ -109,6 +109,13 @@ func TestTxBuilder(t *testing.T) {
 	require.Equal(t, 1, len(txBuilder.GetPubKeys()))
 	require.Equal(t, legacy.Cdc.MustMarshalBinaryBare(pubkey), legacy.Cdc.MustMarshalBinaryBare(txBuilder.GetPubKeys()[0]))
 
+	any, err := codectypes.NewAnyWithValue(testdata.NewTestMsg())
+	require.NoError(t, err)
+	txBuilder.SetExtensionOptions(any)
+	require.Equal(t, []*codectypes.Any{any}, txBuilder.GetExtensionOptions())
+	txBuilder.SetNonCriticalExtensionOptions(any)
+	require.Equal(t, []*codectypes.Any{any}, txBuilder.GetNonCriticalExtensionOptions())
+
 	txBuilder = &builder{}
 	require.NotPanics(t, func() {
 		_ = txBuilder.GetMsgs()