/
authz.go
97 lines (88 loc) · 3.4 KB
/
authz.go
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// 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 := msg.GetAuthorization()
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
}