Problem: don't support blocking addresses

Solution:
- support block addresses in mempool

CHANGELOG.md

@@ -47,6 +47,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 ### Features
 
 * (rpc) [#1682](https://github.com/evmos/ethermint/pull/1682) Add config for maximum number of bytes returned from eth_call.
+* (ante) [#]() Support blocking list of addresses in mempool.
 
 ### Bug Fixes
 

app/ante/ante.go

@@ -29,6 +29,16 @@ func NewAnteHandler(options HandlerOptions) (sdk.AnteHandler, error) {
 		return nil, err
 	}
 
+	blacklist := make(map[string]struct{}, len(options.Blacklist))
+	for _, str := range options.Blacklist {
+		addr, err := sdk.AccAddressFromBech32(str)
+		if err != nil {
+			return nil, fmt.Errorf("invalid bech32 address: %s", str)
+		}
+
+		blacklist[string(addr)] = struct{}{}
+	}
+
 	return func(
 		ctx sdk.Context, tx sdk.Tx, sim bool,
 	) (newCtx sdk.Context, err error) {
@@ -48,6 +58,12 @@ func NewAnteHandler(options HandlerOptions) (sdk.AnteHandler, error) {
 						"vesting messages are not supported",
 					)
 				}
+
+				for _, signer := range msg.GetSigners() {
+					if _, ok := blacklist[string(signer)]; ok {
+						return ctx, fmt.Errorf("signer is blocked: %s", signer.String())
+					}
+				}
 			}
 		}
 

app/ante/handler_options.go

@@ -28,6 +28,7 @@ type HandlerOptions struct {
 	MaxTxGasWanted         uint64
 	ExtensionOptionChecker ante.ExtensionOptionChecker
 	TxFeeChecker           ante.TxFeeChecker
+	Blacklist              []string
 }
 
 func (options HandlerOptions) validate() error {