ante: EIP712 support (#950)

* code migrated

* signed_data ported to avoid conficting dependency

* correct payload

* eip712 working with evmos.me

* use geth TypedData types

* fix linter

* minor refactor

* test first try

* fix test

* fix tests

* enforce fee delegated eip712

* verify signature refactor

* SignedTypedData api refactor

* add AnteHandler test for EIP712

* remove comment

* code clean up

* return more detailed error messages

* fix linter

* remove unnecesary global vars

* Update app/ante/eip712.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* fix pr comments

* remove hardcoded value

* add more tests

* add changelog

* use sdk errors

* add MsgDelegate test

Co-authored-by: Freddy Caceres <freddy.caceres@crypto.com>
Co-authored-by: Federico Kunze Küllmer <federico.kunze94@gmail.com>
Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>
Co-authored-by: crypto-facs <84574577+crypto-facs@users.noreply.github.com>

app/ante/ante.go

@@ -39,6 +39,9 @@ func NewAnteHandler(options HandlerOptions) sdk.AnteHandler {
 				case "/ethermint.evm.v1.ExtensionOptionsEthereumTx":
 					// handle as *evmtypes.MsgEthereumTx
 					anteHandler = newEthAnteHandler(options)
+				case "/ethermint.types.v1.ExtensionOptionsWeb3Tx":
+					// handle as normal Cosmos SDK tx, except signature is checked for EIP712 representation
+					anteHandler = newCosmosAnteHandlerEip712(options)
 				default:
 					return ctx, sdkerrors.Wrapf(
 						sdkerrors.ErrUnknownExtensionOptions,

app/ante/ante_test.go

@@ -1,6 +1,7 @@
 package ante_test
 
 import (
+	"github.com/cosmos/cosmos-sdk/types/tx/signing"
 	"math/big"
 	"strings"
 
@@ -292,6 +293,101 @@ func (suite AnteTestSuite) TestAnteHandler() {
 				return txBuilder.GetTx()
 			}, false, false, false,
 		},
+		{
+			"success - DeliverTx EIP712 signed Cosmos Tx with MsgSend",
+			func() sdk.Tx {
+				from := acc.GetAddress()
+				amount := sdk.NewCoins(sdk.NewCoin(evmtypes.DefaultEVMDenom, sdk.NewInt(20)))
+				gas := uint64(200000)
+				txBuilder := suite.CreateTestEIP712TxBuilderMsgSend(from, privKey, "ethermint_9000-1", gas, amount)
+				return txBuilder.GetTx()
+			}, false, false, true,
+		},
+		{
+			"success - DeliverTx EIP712 signed Cosmos Tx with DelegateMsg",
+			func() sdk.Tx {
+				from := acc.GetAddress()
+				coinAmount := sdk.NewCoin(evmtypes.DefaultEVMDenom, sdk.NewInt(20))
+				amount := sdk.NewCoins(coinAmount)
+				gas := uint64(200000)
+				txBuilder := suite.CreateTestEIP712TxBuilderMsgDelegate(from, privKey, "ethermint_9000-1", gas, amount)
+				return txBuilder.GetTx()
+			}, false, false, true,
+		},
+		{
+			"fails - DeliverTx EIP712 signed Cosmos Tx with wrong Chain ID",
+			func() sdk.Tx {
+				from := acc.GetAddress()
+				amount := sdk.NewCoins(sdk.NewCoin(evmtypes.DefaultEVMDenom, sdk.NewInt(20)))
+				gas := uint64(200000)
+				txBuilder := suite.CreateTestEIP712TxBuilderMsgSend(from, privKey, "ethermint_9002-1", gas, amount)
+				return txBuilder.GetTx()
+			}, false, false, false,
+		},
+		{
+			"fails - DeliverTx EIP712 signed Cosmos Tx with different gas fees",
+			func() sdk.Tx {
+				from := acc.GetAddress()
+				amount := sdk.NewCoins(sdk.NewCoin(evmtypes.DefaultEVMDenom, sdk.NewInt(20)))
+				gas := uint64(200000)
+				txBuilder := suite.CreateTestEIP712TxBuilderMsgSend(from, privKey, "ethermint_9001-1", gas, amount)
+				txBuilder.SetGasLimit(uint64(300000))
+				txBuilder.SetFeeAmount(sdk.NewCoins(sdk.NewCoin(evmtypes.DefaultEVMDenom, sdk.NewInt(30))))
+				return txBuilder.GetTx()
+			}, false, false, false,
+		},
+		{
+			"fails - DeliverTx EIP712 signed Cosmos Tx with empty signature",
+			func() sdk.Tx {
+				from := acc.GetAddress()
+				amount := sdk.NewCoins(sdk.NewCoin(evmtypes.DefaultEVMDenom, sdk.NewInt(20)))
+				gas := uint64(200000)
+				txBuilder := suite.CreateTestEIP712TxBuilderMsgSend(from, privKey, "ethermint_9001-1", gas, amount)
+				sigsV2 := signing.SignatureV2{}
+				txBuilder.SetSignatures(sigsV2)
+				return txBuilder.GetTx()
+			}, false, false, false,
+		},
+		{
+			"fails - DeliverTx EIP712 signed Cosmos Tx with invalid sequence",
+			func() sdk.Tx {
+				from := acc.GetAddress()
+				amount := sdk.NewCoins(sdk.NewCoin(evmtypes.DefaultEVMDenom, sdk.NewInt(20)))
+				gas := uint64(200000)
+				txBuilder := suite.CreateTestEIP712TxBuilderMsgSend(from, privKey, "ethermint_9001-1", gas, amount)
+				nonce, err := suite.app.AccountKeeper.GetSequence(suite.ctx, acc.GetAddress())
+				suite.Require().NoError(err)
+				sigsV2 := signing.SignatureV2{
+					PubKey: privKey.PubKey(),
+					Data: &signing.SingleSignatureData{
+						SignMode: signing.SignMode_SIGN_MODE_LEGACY_AMINO_JSON,
+					},
+					Sequence: nonce - 1,
+				}
+				txBuilder.SetSignatures(sigsV2)
+				return txBuilder.GetTx()
+			}, false, false, false,
+		},
+		{
+			"fails - DeliverTx EIP712 signed Cosmos Tx with invalid signMode",
+			func() sdk.Tx {
+				from := acc.GetAddress()
+				amount := sdk.NewCoins(sdk.NewCoin(evmtypes.DefaultEVMDenom, sdk.NewInt(20)))
+				gas := uint64(200000)
+				txBuilder := suite.CreateTestEIP712TxBuilderMsgSend(from, privKey, "ethermint_9001-1", gas, amount)
+				nonce, err := suite.app.AccountKeeper.GetSequence(suite.ctx, acc.GetAddress())
+				suite.Require().NoError(err)
+				sigsV2 := signing.SignatureV2{
+					PubKey: privKey.PubKey(),
+					Data: &signing.SingleSignatureData{
+						SignMode: signing.SignMode_SIGN_MODE_UNSPECIFIED,
+					},
+					Sequence: nonce,
+				}
+				txBuilder.SetSignatures(sigsV2)
+				return txBuilder.GetTx()
+			}, false, false, false,
+		},
 	}
 
 	for _, tc := range testCases {

app/ante/eip712.go

@@ -0,0 +1,272 @@
+package ante
+
+import (
+	"fmt"
+
+	"github.com/cosmos/cosmos-sdk/codec"
+	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
+	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	"github.com/cosmos/cosmos-sdk/types/tx/signing"
+	authante "github.com/cosmos/cosmos-sdk/x/auth/ante"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	authsigning "github.com/cosmos/cosmos-sdk/x/auth/signing"
+
+	ethcrypto "github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/crypto/secp256k1"
+	"github.com/tharsis/ethermint/crypto/ethsecp256k1"
+	"github.com/tharsis/ethermint/ethereum/eip712"
+	ethermint "github.com/tharsis/ethermint/types"
+	evmtypes "github.com/tharsis/ethermint/x/evm/types"
+)
+
+var ethermintCodec codec.ProtoCodecMarshaler
+
+func init() {
+	registry := codectypes.NewInterfaceRegistry()
+	ethermint.RegisterInterfaces(registry)
+	ethermintCodec = codec.NewProtoCodec(registry)
+}
+
+// Eip712SigVerificationDecorator Verify all signatures for a tx and return an error if any are invalid. Note,
+// the Eip712SigVerificationDecorator decorator will not get executed on ReCheck.
+//
+// CONTRACT: Pubkeys are set in context for all signers before this decorator runs
+// CONTRACT: Tx must implement SigVerifiableTx interface
+type Eip712SigVerificationDecorator struct {
+	ak              evmtypes.AccountKeeper
+	signModeHandler authsigning.SignModeHandler
+}
+
+// NewEip712SigVerificationDecorator creates a new Eip712SigVerificationDecorator
+func NewEip712SigVerificationDecorator(ak evmtypes.AccountKeeper, signModeHandler authsigning.SignModeHandler) Eip712SigVerificationDecorator {
+	return Eip712SigVerificationDecorator{
+		ak:              ak,
+		signModeHandler: signModeHandler,
+	}
+}
+
+// AnteHandle handles validation of EIP712 signed cosmos txs.
+// it is not run on RecheckTx
+func (svd Eip712SigVerificationDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) {
+	// no need to verify signatures on recheck tx
+	if ctx.IsReCheckTx() {
+		return next(ctx, tx, simulate)
+	}
+
+	sigTx, ok := tx.(authsigning.SigVerifiableTx)
+	if !ok {
+		return ctx, sdkerrors.Wrapf(sdkerrors.ErrInvalidType, "tx %T doesn't implement authsigning.SigVerifiableTx", tx)
+	}
+
+	authSignTx, ok := tx.(authsigning.Tx)
+	if !ok {
+		return ctx, sdkerrors.Wrapf(sdkerrors.ErrInvalidType, "tx %T doesn't implement the authsigning.Tx interface", tx)
+	}
+
+	// stdSigs contains the sequence number, account number, and signatures.
+	// When simulating, this would just be a 0-length slice.
+	sigs, err := sigTx.GetSignaturesV2()
+	if err != nil {
+		return ctx, err
+	}
+
+	signerAddrs := sigTx.GetSigners()
+
+	// EIP712 allows just one signature
+	if len(sigs) != 1 {
+		return ctx, sdkerrors.Wrapf(sdkerrors.ErrUnauthorized, "invalid number of signers (%d);  EIP712 signatures allows just one signature", len(sigs))
+	}
+
+	// check that signer length and signature length are the same
+	if len(sigs) != len(signerAddrs) {
+		return ctx, sdkerrors.Wrapf(sdkerrors.ErrUnauthorized, "invalid number of signer;  expected: %d, got %d", len(signerAddrs), len(sigs))
+	}
+
+	// EIP712 has just one signature, avoid looping here and only read index 0
+	i := 0
+	sig := sigs[i]
+
+	acc, err := authante.GetSignerAcc(ctx, svd.ak, signerAddrs[i])
+	if err != nil {
+		return ctx, err
+	}
+
+	// retrieve pubkey
+	pubKey := acc.GetPubKey()
+	if !simulate && pubKey == nil {
+		return ctx, sdkerrors.Wrap(sdkerrors.ErrInvalidPubKey, "pubkey on account is not set")
+	}
+
+	// Check account sequence number.
+	if sig.Sequence != acc.GetSequence() {
+		return ctx, sdkerrors.Wrapf(
+			sdkerrors.ErrWrongSequence,
+			"account sequence mismatch, expected %d, got %d", acc.GetSequence(), sig.Sequence,
+		)
+	}
+
+	// retrieve signer data
+	genesis := ctx.BlockHeight() == 0
+	chainID := ctx.ChainID()
+
+	var accNum uint64
+	if !genesis {
+		accNum = acc.GetAccountNumber()
+	}
+
+	signerData := authsigning.SignerData{
+		ChainID:       chainID,
+		AccountNumber: accNum,
+		Sequence:      acc.GetSequence(),
+	}
+
+	if simulate {
+		return next(ctx, tx, simulate)
+	}
+
+	if err := VerifySignature(pubKey, signerData, sig.Data, svd.signModeHandler, authSignTx); err != nil {
+		errMsg := fmt.Errorf("signature verification failed; please verify account number (%d) and chain-id (%s): %w", accNum, chainID, err)
+		return ctx, sdkerrors.Wrap(sdkerrors.ErrUnauthorized, errMsg.Error())
+	}
+
+	return next(ctx, tx, simulate)
+}
+
+// VerifySignature verifies a transaction signature contained in SignatureData abstracting over different signing modes
+// and single vs multi-signatures.
+func VerifySignature(
+	pubKey cryptotypes.PubKey,
+	signerData authsigning.SignerData,
+	sigData signing.SignatureData,
+	_ authsigning.SignModeHandler,
+	tx authsigning.Tx,
+) error {
+	switch data := sigData.(type) {
+	case *signing.SingleSignatureData:
+		if data.SignMode != signing.SignMode_SIGN_MODE_LEGACY_AMINO_JSON {
+			return sdkerrors.Wrapf(sdkerrors.ErrNotSupported, "unexpected SignatureData %T: wrong SignMode", sigData)
+		}
+
+		// Note: this prevents the user from sending thrash data in the signature field
+		if len(data.Signature) != 0 {
+			return sdkerrors.Wrap(sdkerrors.ErrTooManySignatures, "invalid signature value; EIP712 must have the cosmos transaction signature empty")
+		}
+
+		// @contract: this code is reached only when Msg has Web3Tx extension (so this custom Ante handler flow),
+		// and the signature is SIGN_MODE_LEGACY_AMINO_JSON which is supported for EIP712 for now
+
+		msgs := tx.GetMsgs()
+		if len(msgs) == 0 {
+			return sdkerrors.Wrap(sdkerrors.ErrNoSignatures, "tx doesn't contain any msgs to verify signature")
+		}
+
+		txBytes := legacytx.StdSignBytes(
+			signerData.ChainID,
+			signerData.AccountNumber,
+			signerData.Sequence,
+			tx.GetTimeoutHeight(),
+			legacytx.StdFee{
+				Amount: tx.GetFee(),
+				Gas:    tx.GetGas(),
+			},
+			msgs, tx.GetMemo(),
+		)
+
+		signerChainID, err := ethermint.ParseChainID(signerData.ChainID)
+		if err != nil {
+			return sdkerrors.Wrapf(err, "failed to parse chainID: %s", signerData.ChainID)
+		}
+
+		txWithExtensions, ok := tx.(authante.HasExtensionOptionsTx)
+		if !ok {
+			return sdkerrors.Wrap(sdkerrors.ErrUnknownExtensionOptions, "tx doesnt contain any extensions")
+		}
+		opts := txWithExtensions.GetExtensionOptions()
+		if len(opts) != 1 {
+			return sdkerrors.Wrap(sdkerrors.ErrUnknownExtensionOptions, "tx doesnt contain expected amount of extension options")
+		}
+
+		var optIface ethermint.ExtensionOptionsWeb3TxI
+
+		if err := ethermintCodec.UnpackAny(opts[0], &optIface); err != nil {
+			return sdkerrors.Wrap(err, "failed to proto-unpack ExtensionOptionsWeb3Tx")
+		}
+
+		extOpt, ok := optIface.(*ethermint.ExtensionOptionsWeb3Tx)
+		if !ok {
+			return sdkerrors.Wrap(sdkerrors.ErrInvalidChainID, "unknown extension option")
+		}
+
+		if extOpt.TypedDataChainID != signerChainID.Uint64() {
+			return sdkerrors.Wrap(sdkerrors.ErrInvalidChainID, "invalid chainID")
+		}
+
+		if len(extOpt.FeePayer) == 0 {
+			return sdkerrors.Wrap(sdkerrors.ErrUnknownExtensionOptions, "no feePayer on ExtensionOptionsWeb3Tx")
+		}
+		feePayer, err := sdk.AccAddressFromBech32(extOpt.FeePayer)
+		if err != nil {
+			return sdkerrors.Wrap(err, "failed to parse feePayer from ExtensionOptionsWeb3Tx")
+		}
+
+		feeDelegation := &eip712.FeeDelegationOptions{
+			FeePayer: feePayer,
+		}
+
+		typedData, err := eip712.WrapTxToTypedData(ethermintCodec, extOpt.TypedDataChainID, msgs[0], txBytes, feeDelegation)
+		if err != nil {
+			return sdkerrors.Wrap(err, "failed to pack tx data in EIP712 object")
+		}
+
+		sigHash, err := eip712.ComputeTypedDataHash(typedData)
+		if err != nil {
+			return err
+		}
+
+		feePayerSig := extOpt.FeePayerSig
+		if len(feePayerSig) != ethcrypto.SignatureLength {
+			return sdkerrors.Wrap(sdkerrors.ErrorInvalidSigner, "signature length doesn't match typical [R||S||V] signature 65 bytes")
+		}
+
+		// Remove the recovery offset if needed (ie. Metamask eip712 signature)
+		if feePayerSig[ethcrypto.RecoveryIDOffset] == 27 || feePayerSig[ethcrypto.RecoveryIDOffset] == 28 {
+			feePayerSig[ethcrypto.RecoveryIDOffset] -= 27
+		}
+
+		feePayerPubkey, err := secp256k1.RecoverPubkey(sigHash, feePayerSig)
+		if err != nil {
+			return sdkerrors.Wrap(err, "failed to recover delegated fee payer from sig")
+		}
+
+		ecPubKey, err := ethcrypto.UnmarshalPubkey(feePayerPubkey)
+		if err != nil {
+			return sdkerrors.Wrap(err, "failed to unmarshal recovered fee payer pubkey")
+		}
+
+		pk := &ethsecp256k1.PubKey{
+			Key: ethcrypto.CompressPubkey(ecPubKey),
+		}
+
+		if !pubKey.Equals(pk) {
+			return sdkerrors.Wrapf(sdkerrors.ErrInvalidPubKey, "feePayer pubkey %s is different from transaction pubkey %s", pubKey, pk)
+		}
+
+		recoveredFeePayerAcc := sdk.AccAddress(pk.Address().Bytes())
+
+		if !recoveredFeePayerAcc.Equals(feePayer) {
+			return sdkerrors.Wrapf(sdkerrors.ErrorInvalidSigner, "failed to verify delegated fee payer %s signature", recoveredFeePayerAcc)
+		}
+
+		// VerifySignature of ethsecp256k1 accepts 64 byte signature [R||S]
+		// WARNING! Under NO CIRCUMSTANCES try to use pubKey.VerifySignature there
+		if !secp256k1.VerifySignature(pubKey.Bytes(), sigHash, feePayerSig[:len(feePayerSig)-1]) {
+			return sdkerrors.Wrap(sdkerrors.ErrorInvalidSigner, "unable to verify signer signature of EIP712 typed data")
+		}
+
+		return nil
+	default:
+		return sdkerrors.Wrapf(sdkerrors.ErrTooManySignatures, "unexpected SignatureData %T", sigData)
+	}
+}

app/ante/handler_options.go

@@ -79,3 +79,26 @@ func newCosmosAnteHandler(options HandlerOptions) sdk.AnteHandler {
 		ibcante.NewAnteDecorator(options.IBCChannelKeeper),
 	)
 }
+
+func newCosmosAnteHandlerEip712(options HandlerOptions) sdk.AnteHandler {
+	return sdk.ChainAnteDecorators(
+		RejectMessagesDecorator{}, // reject MsgEthereumTxs
+		ante.NewSetUpContextDecorator(),
+		// NOTE: extensions option decorator removed
+		// ante.NewRejectExtensionOptionsDecorator(),
+		ante.NewMempoolFeeDecorator(),
+		ante.NewValidateBasicDecorator(),
+		ante.NewTxTimeoutHeightDecorator(),
+		ante.NewValidateMemoDecorator(options.AccountKeeper),
+		ante.NewConsumeGasForTxSizeDecorator(options.AccountKeeper),
+		ante.NewDeductFeeDecorator(options.AccountKeeper, options.BankKeeper, options.FeegrantKeeper),
+		// SetPubKeyDecorator must be called before all signature verification decorators
+		ante.NewSetPubKeyDecorator(options.AccountKeeper),
+		ante.NewValidateSigCountDecorator(options.AccountKeeper),
+		ante.NewSigGasConsumeDecorator(options.AccountKeeper, options.SigGasConsumer),
+		// Note: signature verification uses EIP instead of the cosmos signature validator
+		NewEip712SigVerificationDecorator(options.AccountKeeper, options.SignModeHandler),
+		ante.NewIncrementSequenceDecorator(options.AccountKeeper),
+		ibcante.NewAnteDecorator(options.IBCChannelKeeper),
+	)
+}

app/ante/utils_test.go

@@ -1,6 +1,13 @@
 package ante_test
 
 import (
+	"github.com/cosmos/cosmos-sdk/codec"
+	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	types2 "github.com/cosmos/cosmos-sdk/x/bank/types"
+	types3 "github.com/cosmos/cosmos-sdk/x/staking/types"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/tharsis/ethermint/ethereum/eip712"
+	"github.com/tharsis/ethermint/types"
 	"math"
 	"testing"
 	"time"
@@ -191,6 +198,88 @@ func (suite *AnteTestSuite) CreateTestTxBuilder(
 	return txBuilder
 }
 
+func (suite *AnteTestSuite) CreateTestEIP712TxBuilderMsgSend(from sdk.AccAddress, priv cryptotypes.PrivKey, chainId string, gas uint64, gasAmount sdk.Coins) client.TxBuilder {
+	// Build MsgSend
+	recipient := sdk.AccAddress(common.Address{}.Bytes())
+	msgSend := types2.NewMsgSend(from, recipient, sdk.NewCoins(sdk.NewCoin(evmtypes.DefaultEVMDenom, sdk.NewInt(1))))
+	return suite.CreateTestEIP712CosmosTxBuilder(from, priv, chainId, gas, gasAmount, msgSend)
+}
+
+func (suite *AnteTestSuite) CreateTestEIP712TxBuilderMsgDelegate(from sdk.AccAddress, priv cryptotypes.PrivKey, chainId string, gas uint64, gasAmount sdk.Coins) client.TxBuilder {
+	// Build MsgSend
+	valEthAddr := tests.GenerateAddress()
+	valAddr := sdk.ValAddress(valEthAddr.Bytes())
+	msgSend := types3.NewMsgDelegate(from, valAddr, sdk.NewCoin(evmtypes.DefaultEVMDenom, sdk.NewInt(20)))
+	return suite.CreateTestEIP712CosmosTxBuilder(from, priv, chainId, gas, gasAmount, msgSend)
+}
+
+func (suite *AnteTestSuite) CreateTestEIP712CosmosTxBuilder(
+	from sdk.AccAddress, priv cryptotypes.PrivKey, chainId string, gas uint64, gasAmount sdk.Coins, msg sdk.Msg,
+) client.TxBuilder {
+	var err error
+
+	nonce, err := suite.app.AccountKeeper.GetSequence(suite.ctx, from)
+	suite.Require().NoError(err)
+
+	pc, err := types.ParseChainID(chainId)
+	suite.Require().NoError(err)
+	ethChainId := pc.Uint64()
+
+	// GenerateTypedData TypedData
+	var ethermintCodec codec.ProtoCodecMarshaler
+	fee := legacytx.NewStdFee(gas, gasAmount)
+	accNumber := suite.app.AccountKeeper.GetAccount(suite.ctx, from).GetAccountNumber()
+
+	data := legacytx.StdSignBytes(chainId, accNumber, nonce, 0, fee, []sdk.Msg{msg}, "")
+	typedData, err := eip712.WrapTxToTypedData(ethermintCodec, ethChainId, msg, data, &eip712.FeeDelegationOptions{
+		FeePayer: from,
+	})
+	suite.Require().NoError(err)
+
+	sigHash, err := eip712.ComputeTypedDataHash(typedData)
+	suite.Require().NoError(err)
+
+	// Sign typedData
+	keyringSigner := tests.NewSigner(priv)
+	signature, pubKey, err := keyringSigner.SignByAddress(from, sigHash)
+	suite.Require().NoError(err)
+	signature[crypto.RecoveryIDOffset] += 27 // Transform V from 0/1 to 27/28 according to the yellow paper
+
+	// Add ExtensionOptionsWeb3Tx extension
+	var option *codectypes.Any
+	option, err = codectypes.NewAnyWithValue(&types.ExtensionOptionsWeb3Tx{
+		FeePayer:         from.String(),
+		TypedDataChainID: ethChainId,
+		FeePayerSig:      signature,
+	})
+	suite.Require().NoError(err)
+
+	suite.clientCtx.TxConfig.SignModeHandler()
+	txBuilder := suite.clientCtx.TxConfig.NewTxBuilder()
+	builder, ok := txBuilder.(authtx.ExtensionOptionsTxBuilder)
+	suite.Require().True(ok)
+
+	builder.SetExtensionOptions(option)
+	builder.SetFeeAmount(gasAmount)
+	builder.SetGasLimit(gas)
+
+	sigsV2 := signing.SignatureV2{
+		PubKey: pubKey,
+		Data: &signing.SingleSignatureData{
+			SignMode: signing.SignMode_SIGN_MODE_LEGACY_AMINO_JSON,
+		},
+		Sequence: nonce,
+	}
+
+	err = builder.SetSignatures(sigsV2)
+	suite.Require().NoError(err)
+
+	err = builder.SetMsgs(msg)
+	suite.Require().NoError(err)
+
+	return builder
+}
+
 var _ sdk.Tx = &invalidTx{}
 
 type invalidTx struct{}