package ante import ( "fmt" "math/big" sdk "github.com/cosmos/cosmos-sdk/types" sdkerrors "github.com/cosmos/cosmos-sdk/types/errors" "github.com/cosmos/cosmos-sdk/x/auth" authante "github.com/cosmos/cosmos-sdk/x/auth/ante" "github.com/cosmos/cosmos-sdk/x/auth/types" emint "github.com/cosmos/ethermint/types" evmtypes "github.com/cosmos/ethermint/x/evm/types" "github.com/ethereum/go-ethereum/common" ethcore "github.com/ethereum/go-ethereum/core" ) // EVMKeeper defines the expected keeper interface used on the Eth AnteHandler type EVMKeeper interface { GetParams(ctx sdk.Context) evmtypes.Params } // EthSetupContextDecorator sets the infinite GasMeter in the Context and wraps // the next AnteHandler with a defer clause to recover from any downstream // OutOfGas panics in the AnteHandler chain to return an error with information // on gas provided and gas used. // CONTRACT: Must be first decorator in the chain // CONTRACT: Tx must implement GasTx interface type EthSetupContextDecorator struct{} // NewEthSetupContextDecorator creates a new EthSetupContextDecorator func NewEthSetupContextDecorator() EthSetupContextDecorator { return EthSetupContextDecorator{} } // AnteHandle sets the infinite gas meter to done to ignore costs in AnteHandler checks. // This is undone at the EthGasConsumeDecorator, where the context is set with the // ethereum tx GasLimit. func (escd EthSetupContextDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) { ctx = ctx.WithBlockGasMeter(sdk.NewInfiniteGasMeter()) // all transactions must implement GasTx gasTx, ok := tx.(authante.GasTx) if !ok { return ctx, sdkerrors.Wrap(sdkerrors.ErrTxDecode, "Tx must be GasTx") } // Decorator will catch an OutOfGasPanic caused in the next antehandler // AnteHandlers must have their own defer/recover in order for the BaseApp // to know how much gas was used! This is because the GasMeter is created in // the AnteHandler, but if it panics the context won't be set properly in // runTx's recover call. defer func() { if r := recover(); r != nil { switch rType := r.(type) { case sdk.ErrorOutOfGas: log := fmt.Sprintf( "out of gas in location: %v; gasLimit: %d, gasUsed: %d", rType.Descriptor, gasTx.GetGas(), ctx.GasMeter().GasConsumed(), ) err = sdkerrors.Wrap(sdkerrors.ErrOutOfGas, log) default: panic(r) } } }() return next(ctx, tx, simulate) } // EthMempoolFeeDecorator validates that sufficient fees have been provided that // meet a minimum threshold defined by the proposer (for mempool purposes during CheckTx). type EthMempoolFeeDecorator struct { evmKeeper EVMKeeper } // NewEthMempoolFeeDecorator creates a new EthMempoolFeeDecorator func NewEthMempoolFeeDecorator(ek EVMKeeper) EthMempoolFeeDecorator { return EthMempoolFeeDecorator{ evmKeeper: ek, } } // AnteHandle verifies that enough fees have been provided by the // Ethereum transaction that meet the minimum threshold set by the block // proposer. // // NOTE: This should only be run during a CheckTx mode. func (emfd EthMempoolFeeDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) { if !ctx.IsCheckTx() { return next(ctx, tx, simulate) } msgEthTx, ok := tx.(evmtypes.MsgEthereumTx) if !ok { return ctx, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "invalid transaction type: %T", tx) } evmDenom := emfd.evmKeeper.GetParams(ctx).EvmDenom // fee = GP * GL fee := sdk.NewInt64DecCoin(evmDenom, msgEthTx.Fee().Int64()) minGasPrices := ctx.MinGasPrices() // check that fee provided is greater than the minimum // NOTE: we only check if aphotons are present in min gas prices. It is up to the // sender if they want to send additional fees in other denominations. var hasEnoughFees bool if fee.Amount.GTE(minGasPrices.AmountOf(evmDenom)) { hasEnoughFees = true } // reject transaction if minimum gas price is positive and the transaction does not // meet the minimum fee if !ctx.MinGasPrices().IsZero() && !hasEnoughFees { return ctx, sdkerrors.Wrap( sdkerrors.ErrInsufficientFee, fmt.Sprintf("insufficient fee, got: %q required: %q", fee, ctx.MinGasPrices()), ) } return next(ctx, tx, simulate) } // EthSigVerificationDecorator validates an ethereum signature type EthSigVerificationDecorator struct{} // NewEthSigVerificationDecorator creates a new EthSigVerificationDecorator func NewEthSigVerificationDecorator() EthSigVerificationDecorator { return EthSigVerificationDecorator{} } // AnteHandle validates the signature and returns sender address func (esvd EthSigVerificationDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) { msgEthTx, ok := tx.(evmtypes.MsgEthereumTx) if !ok { return ctx, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "invalid transaction type: %T", tx) } // parse the chainID from a string to a base-10 integer chainID, ok := new(big.Int).SetString(ctx.ChainID(), 10) if !ok { return ctx, sdkerrors.Wrap(emint.ErrInvalidChainID, ctx.ChainID()) } // validate sender/signature _, err = msgEthTx.VerifySig(chainID) if err != nil { return ctx, sdkerrors.Wrap(sdkerrors.ErrUnauthorized, fmt.Sprintf("signature verification failed: %s", err.Error())) } // NOTE: when signature verification succeeds, a non-empty signer address can be // retrieved from the transaction on the next AnteDecorators. return next(ctx, msgEthTx, simulate) } // AccountVerificationDecorator validates an account balance checks type AccountVerificationDecorator struct { ak auth.AccountKeeper evmKeeper EVMKeeper } // NewAccountVerificationDecorator creates a new AccountVerificationDecorator func NewAccountVerificationDecorator(ak auth.AccountKeeper, ek EVMKeeper) AccountVerificationDecorator { return AccountVerificationDecorator{ ak: ak, evmKeeper: ek, } } // AnteHandle validates the signature and returns sender address func (avd AccountVerificationDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) { if !ctx.IsCheckTx() { return next(ctx, tx, simulate) } msgEthTx, ok := tx.(evmtypes.MsgEthereumTx) if !ok { return ctx, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "invalid transaction type: %T", tx) } // sender address should be in the tx cache from the previous AnteHandle call address := msgEthTx.From() if address.Empty() { panic("sender address cannot be empty") } acc := avd.ak.GetAccount(ctx, address) if acc == nil { acc = avd.ak.NewAccountWithAddress(ctx, address) avd.ak.SetAccount(ctx, acc) } // on InitChain make sure account number == 0 if ctx.BlockHeight() == 0 && acc.GetAccountNumber() != 0 { return ctx, sdkerrors.Wrapf( sdkerrors.ErrInvalidSequence, "invalid account number for height zero (got %d)", acc.GetAccountNumber(), ) } evmDenom := avd.evmKeeper.GetParams(ctx).EvmDenom // validate sender has enough funds to pay for gas cost balance := acc.GetCoins().AmountOf(evmDenom) if balance.BigInt().Cmp(msgEthTx.Cost()) < 0 { return ctx, sdkerrors.Wrapf( sdkerrors.ErrInsufficientFunds, "sender balance < tx gas cost (%s%s < %s%s)", balance.String(), evmDenom, msgEthTx.Cost().String(), evmDenom, ) } return next(ctx, tx, simulate) } // NonceVerificationDecorator that the account nonce from the transaction matches // the sender account sequence. type NonceVerificationDecorator struct { ak auth.AccountKeeper } // NewNonceVerificationDecorator creates a new NonceVerificationDecorator func NewNonceVerificationDecorator(ak auth.AccountKeeper) NonceVerificationDecorator { return NonceVerificationDecorator{ ak: ak, } } // AnteHandle validates that the transaction nonce is valid (equivalent to the sender account’s // current nonce). func (nvd NonceVerificationDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) { msgEthTx, ok := tx.(evmtypes.MsgEthereumTx) if !ok { return ctx, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "invalid transaction type: %T", tx) } // sender address should be in the tx cache from the previous AnteHandle call address := msgEthTx.From() if address.Empty() { panic("sender address cannot be empty") } acc := nvd.ak.GetAccount(ctx, address) if acc == nil { return ctx, fmt.Errorf("account %s (%s) is nil", common.BytesToAddress(address.Bytes()), address) } seq := acc.GetSequence() if msgEthTx.Data.AccountNonce != seq { return ctx, sdkerrors.Wrap( sdkerrors.ErrInvalidSequence, fmt.Sprintf("invalid nonce; got %d, expected %d", msgEthTx.Data.AccountNonce, seq), ) } return next(ctx, tx, simulate) } // EthGasConsumeDecorator validates enough intrinsic gas for the transaction and // gas consumption. type EthGasConsumeDecorator struct { ak auth.AccountKeeper sk types.SupplyKeeper evmKeeper EVMKeeper } // NewEthGasConsumeDecorator creates a new EthGasConsumeDecorator func NewEthGasConsumeDecorator(ak auth.AccountKeeper, sk types.SupplyKeeper, ek EVMKeeper) EthGasConsumeDecorator { return EthGasConsumeDecorator{ ak: ak, sk: sk, evmKeeper: ek, } } // AnteHandle validates that the Ethereum tx message has enough to cover intrinsic gas // (during CheckTx only) and that the sender has enough balance to pay for the gas cost. // // Intrinsic gas for a transaction is the amount of gas // that the transaction uses before the transaction is executed. The gas is a // constant value of 21000 plus any cost inccured by additional bytes of data // supplied with the transaction. func (egcd EthGasConsumeDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) { msgEthTx, ok := tx.(evmtypes.MsgEthereumTx) if !ok { return ctx, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "invalid transaction type: %T", tx) } // sender address should be in the tx cache address := msgEthTx.From() if address.Empty() { panic("sender address cannot be empty") } // Fetch sender account from signature senderAcc, err := auth.GetSignerAcc(ctx, egcd.ak, address) if err != nil { return ctx, err } if senderAcc == nil { return ctx, fmt.Errorf("sender account %s (%s) is nil", common.BytesToAddress(address.Bytes()), address) } gasLimit := msgEthTx.GetGas() gas, err := ethcore.IntrinsicGas(msgEthTx.Data.Payload, msgEthTx.To() == nil, true, false) if err != nil { return ctx, sdkerrors.Wrap(err, "failed to compute intrinsic gas cost") } // intrinsic gas verification during CheckTx if ctx.IsCheckTx() && gasLimit < gas { return ctx, fmt.Errorf("intrinsic gas too low: %d < %d", gasLimit, gas) } // Charge sender for gas up to limit if gasLimit != 0 { // Cost calculates the fees paid to validators based on gas limit and price cost := new(big.Int).Mul(msgEthTx.Data.Price, new(big.Int).SetUint64(gasLimit)) evmDenom := egcd.evmKeeper.GetParams(ctx).EvmDenom feeAmt := sdk.NewCoins( sdk.NewCoin(evmDenom, sdk.NewIntFromBigInt(cost)), ) err = auth.DeductFees(egcd.sk, ctx, senderAcc, feeAmt) if err != nil { return ctx, err } } // Set gas meter after ante handler to ignore gaskv costs newCtx = auth.SetGasMeter(simulate, ctx, gasLimit) return next(newCtx, tx, simulate) } // IncrementSenderSequenceDecorator increments the sequence of the signers. The // main difference with the SDK's IncrementSequenceDecorator is that the MsgEthereumTx // doesn't implement the SigVerifiableTx interface. // // CONTRACT: must be called after msg.VerifySig in order to cache the sender address. type IncrementSenderSequenceDecorator struct { ak auth.AccountKeeper } // NewIncrementSenderSequenceDecorator creates a new IncrementSenderSequenceDecorator. func NewIncrementSenderSequenceDecorator(ak auth.AccountKeeper) IncrementSenderSequenceDecorator { return IncrementSenderSequenceDecorator{ ak: ak, } } // AnteHandle handles incrementing the sequence of the sender. func (issd IncrementSenderSequenceDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (sdk.Context, error) { // get and set account must be called with an infinite gas meter in order to prevent // additional gas from being deducted. gasMeter := ctx.GasMeter() ctx = ctx.WithGasMeter(sdk.NewInfiniteGasMeter()) msgEthTx, ok := tx.(evmtypes.MsgEthereumTx) if !ok { ctx = ctx.WithGasMeter(gasMeter) return ctx, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "invalid transaction type: %T", tx) } // increment sequence of all signers for _, addr := range msgEthTx.GetSigners() { acc := issd.ak.GetAccount(ctx, addr) if err := acc.SetSequence(acc.GetSequence() + 1); err != nil { panic(err) } issd.ak.SetAccount(ctx, acc) } // set the original gas meter ctx = ctx.WithGasMeter(gasMeter) return next(ctx, tx, simulate) }