Problem: insufficient invalid value check in eth transaction

CHANGELOG.md

@@ -76,6 +76,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (deps) [#489](https://github.com/crypto-org-chain/ethermint/pull/489) Update cosmos-sdk to `v0.50.7`.
 * (rpc) [#491](https://github.com/crypto-org-chain/ethermint/pull/491) Avoid unnecessary tx decode in tx listener.
 * [#496](https://github.com/crypto-org-chain/cronos/pull/496) Set mempool MaxTx from config.
+* (ante) [#497](https://github.com/crypto-org-chain/ethermint/pull/497) Enforce positive value check in eth transaction.
 
 ## v0.21.x-cronos
 

app/ante/eth.go

@@ -16,6 +16,7 @@
 package ante
 
 import (
+	"fmt"
 	"math"
 	"math/big"
 
@@ -216,15 +217,18 @@ func CheckEthCanTransfer(
 				)
 			}
 		}
-
+		value := tx.Value()
+		if value == nil || value.Sign() == -1 {
+			return fmt.Errorf("value (%s) must be positive", value)
+		}
 		from := common.BytesToAddress(msgEthTx.From)
 		// check that caller has enough balance to cover asset transfer for **topmost** call
 		// NOTE: here the gas consumed is from the context with the infinite gas meter
-		if tx.Value().Sign() > 0 && !canTransfer(ctx, evmKeeper, evmParams.EvmDenom, from, tx.Value()) {
+		if value.Sign() > 0 && !canTransfer(ctx, evmKeeper, evmParams.EvmDenom, from, value) {
 			return errorsmod.Wrapf(
 				errortypes.ErrInsufficientFunds,
 				"failed to transfer %s from address %s using the EVM block context transfer function",
-				tx.Value(),
+				value,
 				from,
 			)
 		}

app/ante/eth_test.go

@@ -353,11 +353,24 @@ func (suite *AnteTestSuite) TestCanTransferDecorator() {
 		nil,
 		&ethtypes.AccessList{},
 	)
+	tx3 := evmtypes.NewTxContract(
+		suite.app.EvmKeeper.ChainID(),
+		1,
+		big.NewInt(-10),
+		1000,
+		big.NewInt(150),
+		big.NewInt(200),
+		nil,
+		nil,
+		&ethtypes.AccessList{},
+	)
 
-	tx.From = addr.Bytes()
+	for _, tx := range []*evmtypes.MsgEthereumTx{tx, tx3} {
+		tx.From = addr.Bytes()
 
-	err := tx.Sign(suite.ethSigner, tests.NewSigner(privKey))
-	suite.Require().NoError(err)
+		err := tx.Sign(suite.ethSigner, tests.NewSigner(privKey))
+		suite.Require().NoError(err)
+	}
 
 	var vmdb *statedb.StateDB
 
@@ -369,6 +382,7 @@ func (suite *AnteTestSuite) TestCanTransferDecorator() {
 	}{
 		{"invalid transaction type", &invalidTx{}, func() {}, false},
 		{"AsMessage failed", tx2, func() {}, false},
+		{"negative value", tx3, func() {}, false},
 		{
 			"evm CanTransfer failed",
 			tx,