fix: add authz ante handler

app/ante/ante_test.go

@@ -798,7 +798,7 @@ func (suite AnteTestSuite) TestAnteHandler() {
 					signing.SignMode_SIGN_MODE_DIRECT,
 					msg,
 					"ethermint_9000-1",
-					2000,
+					2000000,
 					"EIP-712",
 				)
 
@@ -831,7 +831,7 @@ func (suite AnteTestSuite) TestAnteHandler() {
 					signing.SignMode_SIGN_MODE_DIRECT,
 					msg,
 					"ethermint_9000-1",
-					2000,
+					2000000,
 					"EIP-712",
 				)
 
@@ -860,12 +860,48 @@ func (suite AnteTestSuite) TestAnteHandler() {
 					signing.SignMode_SIGN_MODE_DIRECT,
 					msg,
 					"ethermint_9000-1",
-					2000,
+					2000000,
 					"EIP-712",
 				)
 
 				txBuilder.SetMsgs(msg, msg)
 
+				return txBuilder.GetTx()
+			}, false, false, false,
+		},
+		{
+			"Fails - Authz Exec with unauthorized message",
+			func() sdk.Tx {
+				ethTx := evmtypes.NewTx(
+					suite.app.EvmKeeper.ChainID(),
+					1,
+					&to,
+					big.NewInt(10),
+					100000,
+					big.NewInt(150),
+					big.NewInt(200),
+					nil,
+					nil,
+					nil,
+				)
+				ethTx.From = addr.Hex()
+
+				msg := authz.NewMsgExec(
+					sdk.AccAddress(privKey.PubKey().Address()),
+					[]sdk.Msg{ethTx},
+				)
+
+				txBuilder := suite.CreateTestSingleSignedTx(
+					privKey,
+					signing.SignMode_SIGN_MODE_LEGACY_AMINO_JSON,
+					&msg,
+					"ethermint_9000-1",
+					200000,
+					"",
+				)
+
+				txBuilder.SetMsgs(&msg)
+
 				return txBuilder.GetTx()
 			}, false, false, false,
 		},

app/ante/authz.go

@@ -0,0 +1,101 @@
+// Copyright 2021 Evmos Foundation
+// This file is part of Evmos' Ethermint library.
+//
+// The Ethermint library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The Ethermint library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the Ethermint library. If not, see https://github.com/evmos/ethermint/blob/main/LICENSE
+package ante
+
+import (
+	"fmt"
+
+	errorsmod "cosmossdk.io/errors"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	errortypes "github.com/cosmos/cosmos-sdk/types/errors"
+	"github.com/cosmos/cosmos-sdk/x/authz"
+)
+
+// maxNestedMsgs defines a cap for the number of nested messages on a MsgExec message
+const maxNestedMsgs = 6
+
+// AuthzLimiterDecorator blocks certain msg types from being granted or executed
+// within the authorization module.
+type AuthzLimiterDecorator struct {
+	// disabledMsgs is a set that contains type urls of unauthorized msgs.
+	disabledMsgs map[string]struct{}
+}
+
+// NewAuthzLimiterDecorator creates a decorator to block certain msg types
+// from being granted or executed within authz.
+func NewAuthzLimiterDecorator(disabledMsgTypes []string) AuthzLimiterDecorator {
+	disabledMsgs := make(map[string]struct{})
+	for _, url := range disabledMsgTypes {
+		disabledMsgs[url] = struct{}{}
+	}
+
+	return AuthzLimiterDecorator{
+		disabledMsgs: disabledMsgs,
+	}
+}
+
+func (ald AuthzLimiterDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (newCtx sdk.Context, err error) {
+	if err := ald.checkDisabledMsgs(tx.GetMsgs(), false, 0); err != nil {
+		return ctx, errorsmod.Wrapf(errortypes.ErrUnauthorized, err.Error())
+	}
+	return next(ctx, tx, simulate)
+}
+
+// checkDisabledMsgs iterates through the msgs and returns an error if it finds any unauthorized msgs.
+//
+// This method is recursive as MsgExec's can wrap other MsgExecs. nestedMsgs sets a reasonable limit on
+// the total messages, regardless of how they are nested.
+func (ald AuthzLimiterDecorator) checkDisabledMsgs(msgs []sdk.Msg, isAuthzInnerMsg bool, nestedMsgs int) error {
+	if nestedMsgs >= maxNestedMsgs {
+		return fmt.Errorf("found more nested msgs than permitted. Limit is : %d", maxNestedMsgs)
+	}
+	for _, msg := range msgs {
+		switch msg := msg.(type) {
+		case *authz.MsgExec:
+			innerMsgs, err := msg.GetMessages()
+			if err != nil {
+				return err
+			}
+			nestedMsgs++
+			if err := ald.checkDisabledMsgs(innerMsgs, true, nestedMsgs); err != nil {
+				return err
+			}
+		case *authz.MsgGrant:
+			authorization, err := msg.GetAuthorization()
+			if err != nil {
+				return err
+			}
+
+			url := authorization.MsgTypeURL()
+			if ald.isDisabledMsg(url) {
+				return fmt.Errorf("found disabled msg type: %s", url)
+			}
+		default:
+			url := sdk.MsgTypeURL(msg)
+			if isAuthzInnerMsg && ald.isDisabledMsg(url) {
+				return fmt.Errorf("found disabled msg type: %s", url)
+			}
+		}
+	}
+	return nil
+}
+
+// isDisabledMsg returns true if the given message is in the set of restricted
+// messages from the AnteHandler.
+func (ald AuthzLimiterDecorator) isDisabledMsg(msgTypeURL string) bool {
+	_, ok := ald.disabledMsgs[msgTypeURL]
+	return ok
+}