From b70bbaf5906d381b046c3ad89afb0045b73b3cb5 Mon Sep 17 00:00:00 2001
From: Dheeraj Dubey <dheeraj@comdex.one>
Date: Wed, 1 Mar 2023 06:53:10 +0530
Subject: [PATCH] Add initial(25%) deposit for gov proposals to prevent spams

---
 app/ante.go                  |  6 +++
 app/app.go                   |  2 +
 app/decorators/gov_filter.go | 88 ++++++++++++++++++++++++++++++++++++
 3 files changed, 96 insertions(+)
 create mode 100644 app/decorators/gov_filter.go

diff --git a/app/ante.go b/app/ante.go
index 72c29ae9c..5516326b1 100644
--- a/app/ante.go
+++ b/app/ante.go
@@ -3,9 +3,12 @@ package app
 import (
 	"github.com/CosmWasm/wasmd/x/wasm"
 	wasmkeeper "github.com/CosmWasm/wasmd/x/wasm/keeper"
+	"github.com/comdex-official/comdex/app/decorators"
+	"github.com/cosmos/cosmos-sdk/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/x/auth/ante"
+	govkeeper "github.com/cosmos/cosmos-sdk/x/gov/keeper"
 	ibcante "github.com/cosmos/ibc-go/v4/modules/core/ante"
 	ibckeeper "github.com/cosmos/ibc-go/v4/modules/core/keeper"
 )
@@ -17,6 +20,8 @@ type HandlerOptions struct {
 	wasmConfig        wasm.Config
 	txCounterStoreKey sdk.StoreKey
 	IBCChannelKeeper  *ibckeeper.Keeper
+	GovKeeper         govkeeper.Keeper
+	Cdc               codec.BinaryCodec
 }
 
 func NewAnteHandler(options HandlerOptions) (sdk.AnteHandler, error) {
@@ -40,6 +45,7 @@ func NewAnteHandler(options HandlerOptions) (sdk.AnteHandler, error) {
 		wasmkeeper.NewLimitSimulationGasDecorator(options.wasmConfig.SimulationGasLimit),
 		wasmkeeper.NewCountTXDecorator(options.txCounterStoreKey),
 		ante.NewRejectExtensionOptionsDecorator(),
+		decorators.NewGovPreventSpamDecorator(options.Cdc, options.GovKeeper),
 		ante.NewMempoolFeeDecorator(),
 		ante.NewValidateBasicDecorator(),
 		ante.NewTxTimeoutHeightDecorator(),
diff --git a/app/app.go b/app/app.go
index 7b3b02d6b..b394dfc1a 100644
--- a/app/app.go
+++ b/app/app.go
@@ -996,9 +996,11 @@ func New(
 				SignModeHandler: encoding.TxConfig.SignModeHandler(),
 				SigGasConsumer:  ante.DefaultSigVerificationGasConsumer,
 			},
+			GovKeeper:         app.GovKeeper,
 			wasmConfig:        wasmConfig,
 			txCounterStoreKey: app.GetKey(wasm.StoreKey),
 			IBCChannelKeeper:  app.IbcKeeper,
+			Cdc:               appCodec,
 		},
 	)
 	if err != nil {
diff --git a/app/decorators/gov_filter.go b/app/decorators/gov_filter.go
new file mode 100644
index 000000000..966be7653
--- /dev/null
+++ b/app/decorators/gov_filter.go
@@ -0,0 +1,88 @@
+package decorators
+
+import (
+	"github.com/cosmos/cosmos-sdk/codec"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	"github.com/cosmos/cosmos-sdk/x/authz"
+	govkeeper "github.com/cosmos/cosmos-sdk/x/gov/keeper"
+	govtypes "github.com/cosmos/cosmos-sdk/x/gov/types"
+)
+
+var MiniumInitialDepositRate = sdk.NewDecWithPrec(25, 2)
+
+type GovPreventSpamDecorator struct {
+	govKeeper govkeeper.Keeper
+	cdc       codec.BinaryCodec
+}
+
+func NewGovPreventSpamDecorator(cdc codec.BinaryCodec, govKeeper govkeeper.Keeper) GovPreventSpamDecorator {
+	return GovPreventSpamDecorator{
+		govKeeper: govKeeper,
+		cdc:       cdc,
+	}
+}
+
+func (gpsd GovPreventSpamDecorator) AnteHandle(
+	ctx sdk.Context, tx sdk.Tx,
+	simulate bool, next sdk.AnteHandler,
+) (newCtx sdk.Context, err error) {
+	msgs := tx.GetMsgs()
+
+	err = gpsd.checkSpamSubmitProposalMsg(ctx, msgs)
+
+	if err != nil {
+		return ctx, err
+	}
+
+	return next(ctx, tx, simulate)
+}
+
+func (gpsd GovPreventSpamDecorator) checkSpamSubmitProposalMsg(ctx sdk.Context, msgs []sdk.Msg) error {
+	validMsg := func(m sdk.Msg) error {
+		if msg, ok := m.(*govtypes.MsgSubmitProposal); ok {
+			// prevent spam gov msg
+			depositParams := gpsd.govKeeper.GetDepositParams(ctx)
+			miniumInitialDeposit := gpsd.calcMiniumInitialDeposit(depositParams.MinDeposit)
+			if msg.InitialDeposit.IsAllLT(miniumInitialDeposit) {
+				return sdkerrors.Wrapf(sdkerrors.ErrUnauthorized, "not enough initial deposit. required: %v", miniumInitialDeposit)
+			}
+		}
+		return nil
+	}
+
+	// Check every msg in the tx, if it's a MsgExec, check the inner msgs.
+	// If it's a MsgSubmitProposal, check the initial deposit is enough.
+	for _, m := range msgs {
+		var innerMsg sdk.Msg
+		if msg, ok := m.(*authz.MsgExec); ok {
+			for _, v := range msg.Msgs {
+				err := gpsd.cdc.UnpackAny(v, &innerMsg)
+				if err != nil {
+					return sdkerrors.Wrapf(sdkerrors.ErrUnauthorized, "cannot unmarshal authz exec msgs")
+				}
+
+				err = validMsg(innerMsg)
+				if err != nil {
+					return err
+				}
+			}
+		} else {
+			err := validMsg(m)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func (gpsd GovPreventSpamDecorator) calcMiniumInitialDeposit(minDeposit sdk.Coins) (miniumInitialDeposit sdk.Coins) {
+	for _, coin := range minDeposit {
+		miniumInitialCoin := MiniumInitialDepositRate.MulInt(coin.Amount).RoundInt()
+		miniumInitialDeposit = miniumInitialDeposit.Add(sdk.NewCoin(coin.Denom, miniumInitialCoin))
+	}
+
+	return
+}