wasm_hook.go

package ibc_hooks

import (
	"encoding/json"
	"fmt"

	wasmkeeper "github.com/CosmWasm/wasmd/x/wasm/keeper"
	wasmtypes "github.com/CosmWasm/wasmd/x/wasm/types"
	"github.com/cosmos/ibc-apps/modules/ibc-hooks/v8/keeper"
	"github.com/cosmos/ibc-apps/modules/ibc-hooks/v8/types"

	errors "cosmossdk.io/errors"
	sdkmath "cosmossdk.io/math"

	sdk "github.com/cosmos/cosmos-sdk/types"

	capabilitytypes "github.com/cosmos/ibc-go/modules/capability/types"
	transfertypes "github.com/cosmos/ibc-go/v8/modules/apps/transfer/types"
	ibcclienttypes "github.com/cosmos/ibc-go/v8/modules/core/02-client/types"
	channeltypes "github.com/cosmos/ibc-go/v8/modules/core/04-channel/types"
	ibcexported "github.com/cosmos/ibc-go/v8/modules/core/exported"
)

type ContractAck struct {
	ContractResult []byte `json:"contract_result"`
	IbcAck         []byte `json:"ibc_ack"`
}

type WasmHooks struct {
	ContractKeeper      *wasmkeeper.Keeper
	ibcHooksKeeper      *keeper.Keeper
	bech32PrefixAccAddr string
}

func NewWasmHooks(ibcHooksKeeper *keeper.Keeper, contractKeeper *wasmkeeper.Keeper, bech32PrefixAccAddr string) WasmHooks {
	return WasmHooks{
		ContractKeeper:      contractKeeper,
		ibcHooksKeeper:      ibcHooksKeeper,
		bech32PrefixAccAddr: bech32PrefixAccAddr,
	}
}

func (h WasmHooks) ProperlyConfigured() bool {
	return h.ContractKeeper != nil && h.ibcHooksKeeper != nil
}

func (h WasmHooks) OnRecvPacketOverride(im IBCMiddleware, ctx sdk.Context, packet channeltypes.Packet, relayer sdk.AccAddress) ibcexported.Acknowledgement {
	if !h.ProperlyConfigured() {
		// Not configured
		return im.App.OnRecvPacket(ctx, packet, relayer)
	}
	isIcs20, data := isIcs20Packet(packet.GetData())
	if !isIcs20 {
		return im.App.OnRecvPacket(ctx, packet, relayer)
	}

	// Validate the memo
	isWasmRouted, contractAddr, msgBytes, err := ValidateAndParseMemo(data.GetMemo(), data.Receiver)
	if !isWasmRouted {
		return im.App.OnRecvPacket(ctx, packet, relayer)
	}
	if err != nil {
		return NewEmitErrorAcknowledgement(ctx, types.ErrMsgValidation, err.Error())
	}
	if msgBytes == nil || contractAddr == nil { // This should never happen
		return NewEmitErrorAcknowledgement(ctx, types.ErrMsgValidation)
	}

	// Calculate the receiver / contract caller based on the packet's channel and sender
	channel := packet.GetDestChannel()
	sender := data.GetSender()
	senderBech32, err := keeper.DeriveIntermediateSender(channel, sender, h.bech32PrefixAccAddr)
	if err != nil {
		return NewEmitErrorAcknowledgement(ctx, types.ErrBadSender, fmt.Sprintf("cannot convert sender address %s/%s to bech32: %s", channel, sender, err.Error()))
	}

	// The funds sent on this packet need to be transferred to the intermediary account for the sender.
	// For this, we override the ICS20 packet's Receiver (essentially hijacking the funds to this new address)
	// and execute the underlying OnRecvPacket() call (which should eventually land on the transfer app's
	// relay.go and send the sunds to the intermediary account.
	//
	// If that succeeds, we make the contract call
	data.Receiver = senderBech32
	bz, err := json.Marshal(data)
	if err != nil {
		return NewEmitErrorAcknowledgement(ctx, types.ErrMarshaling, err.Error())
	}
	packet.Data = bz

	// Execute the receive
	ack := im.App.OnRecvPacket(ctx, packet, relayer)
	if !ack.Success() {
		return ack
	}

	amount, ok := sdkmath.NewIntFromString(data.GetAmount())
	if !ok {
		// This should never happen, as it should've been caught in the underlying call to OnRecvPacket,
		// but returning here for completeness
		return NewEmitErrorAcknowledgement(ctx, types.ErrInvalidPacket, "Amount is not an int")
	}

	// The packet's denom is the denom in the sender chain. This needs to be converted to the local denom.
	denom := MustExtractDenomFromPacketOnRecv(packet)
	funds := sdk.NewCoins(sdk.NewCoin(denom, amount))

	// Execute the contract
	execMsg := wasmtypes.MsgExecuteContract{
		Sender:   senderBech32,
		Contract: contractAddr.String(),
		Msg:      msgBytes,
		Funds:    funds,
	}
	response, err := h.execWasmMsg(ctx, &execMsg)
	if err != nil {
		return NewEmitErrorAcknowledgement(ctx, types.ErrWasmError, err.Error())
	}

	fullAck := ContractAck{ContractResult: response.Data, IbcAck: ack.Acknowledgement()}
	bz, err = json.Marshal(fullAck)
	if err != nil {
		return NewEmitErrorAcknowledgement(ctx, types.ErrBadResponse, err.Error())
	}

	return channeltypes.NewResultAcknowledgement(bz)
}

func (h WasmHooks) execWasmMsg(ctx sdk.Context, execMsg *wasmtypes.MsgExecuteContract) (*wasmtypes.MsgExecuteContractResponse, error) {
	if err := execMsg.ValidateBasic(); err != nil {
		return nil, fmt.Errorf(types.ErrBadExecutionMsg, err.Error())
	}
	wasmMsgServer := wasmkeeper.NewMsgServerImpl(h.ContractKeeper)
	return wasmMsgServer.ExecuteContract(sdk.WrapSDKContext(ctx), execMsg)
}

func isIcs20Packet(data []byte) (isIcs20 bool, ics20data transfertypes.FungibleTokenPacketData) {
	var packetdata transfertypes.FungibleTokenPacketData
	if err := json.Unmarshal(data, &packetdata); err != nil {
		return false, packetdata
	}
	return true, packetdata
}

// jsonStringHasKey parses the memo as a json object and checks if it contains the key.
func jsonStringHasKey(memo, key string) (found bool, jsonObject map[string]interface{}) {
	jsonObject = make(map[string]interface{})

	// If there is no memo, the packet was either sent with an earlier version of IBC, or the memo was
	// intentionally left blank. Nothing to do here. Ignore the packet and pass it down the stack.
	if len(memo) == 0 {
		return false, jsonObject
	}

	// the jsonObject must be a valid JSON object
	err := json.Unmarshal([]byte(memo), &jsonObject)
	if err != nil {
		return false, jsonObject
	}

	// If the key doesn't exist, there's nothing to do on this hook. Continue by passing the packet
	// down the stack
	_, ok := jsonObject[key]
	if !ok {
		return false, jsonObject
	}

	return true, jsonObject
}

func ValidateAndParseMemo(memo string, receiver string) (isWasmRouted bool, contractAddr sdk.AccAddress, msgBytes []byte, err error) {
	isWasmRouted, metadata := jsonStringHasKey(memo, "wasm")
	if !isWasmRouted {
		return isWasmRouted, sdk.AccAddress{}, nil, nil
	}

	wasmRaw := metadata["wasm"]

	// Make sure the wasm key is a map. If it isn't, ignore this packet
	wasm, ok := wasmRaw.(map[string]interface{})
	if !ok {
		return isWasmRouted, sdk.AccAddress{}, nil,
			fmt.Errorf(types.ErrBadMetadataFormatMsg, memo, "wasm metadata is not a valid JSON map object")
	}

	// Get the contract
	contract, ok := wasm["contract"].(string)
	if !ok {
		// The tokens will be returned
		return isWasmRouted, sdk.AccAddress{}, nil,
			fmt.Errorf(types.ErrBadMetadataFormatMsg, memo, `Could not find key wasm["contract"]`)
	}

	contractAddr, err = sdk.AccAddressFromBech32(contract)
	if err != nil {
		return isWasmRouted, sdk.AccAddress{}, nil,
			fmt.Errorf(types.ErrBadMetadataFormatMsg, memo, `wasm["contract"] is not a valid bech32 address`)
	}

	// The contract and the receiver should be the same for the packet to be valid
	if contract != receiver {
		return isWasmRouted, sdk.AccAddress{}, nil,
			fmt.Errorf(types.ErrBadMetadataFormatMsg, memo, `wasm["contract"] should be the same as the receiver of the packet`)
	}

	// Ensure the message key is provided
	if wasm["msg"] == nil {
		return isWasmRouted, sdk.AccAddress{}, nil,
			fmt.Errorf(types.ErrBadMetadataFormatMsg, memo, `Could not find key wasm["msg"]`)
	}

	// Make sure the msg key is a map. If it isn't, return an error
	_, ok = wasm["msg"].(map[string]interface{})
	if !ok {
		return isWasmRouted, sdk.AccAddress{}, nil,
			fmt.Errorf(types.ErrBadMetadataFormatMsg, memo, `wasm["msg"] is not a map object`)
	}

	// Get the message string by serializing the map
	msgBytes, err = json.Marshal(wasm["msg"])
	if err != nil {
		// The tokens will be returned
		return isWasmRouted, sdk.AccAddress{}, nil,
			fmt.Errorf(types.ErrBadMetadataFormatMsg, memo, err.Error())
	}

	return isWasmRouted, contractAddr, msgBytes, nil
}

func (h WasmHooks) SendPacketOverride(i ICS4Middleware, ctx sdk.Context, chanCap *capabilitytypes.Capability, sourcePort string, sourceChannel string, timeoutHeight ibcclienttypes.Height, timeoutTimestamp uint64, data []byte) (sequence uint64, err error) {
	isIcs20, ics20data := isIcs20Packet(data)
	if !isIcs20 {
		return i.channel.SendPacket(ctx, chanCap, sourcePort, sourceChannel, timeoutHeight, timeoutTimestamp, data) // continue
	}

	isCallbackRouted, metadata := jsonStringHasKey(ics20data.GetMemo(), types.IBCCallbackKey)
	if !isCallbackRouted {
		return i.channel.SendPacket(ctx, chanCap, sourcePort, sourceChannel, timeoutHeight, timeoutTimestamp, data) // continue
	}

	// We remove the callback metadata from the memo as it has already been processed.

	// If the only available key in the memo is the callback, we should remove the memo
	// from the data completely so the packet is sent without it.
	// This way receiver chains that are on old versions of IBC will be able to process the packet
	callbackRaw := metadata[types.IBCCallbackKey] // This will be used later.
	delete(metadata, types.IBCCallbackKey)
	bzMetadata, err := json.Marshal(metadata)
	if err != nil {
		return 0, errors.Wrap(err, "ibc_callback marshall error")
	}
	stringMetadata := string(bzMetadata)
	if stringMetadata == "{}" {
		ics20data.Memo = ""
	} else {
		ics20data.Memo = stringMetadata
	}
	dataBytes, err := json.Marshal(ics20data)
	if err != nil {
		return 0, errors.Wrap(err, "ics20data marshall error")
	}

	seq, err := i.channel.SendPacket(ctx, chanCap, sourcePort, sourceChannel, timeoutHeight, timeoutTimestamp, dataBytes)
	if err != nil {
		return 0, err
	}

	// Make sure the callback contract is a string and a valid bech32 addr. If it isn't, ignore this packet
	contract, ok := callbackRaw.(string)
	if !ok {
		return 0, nil
	}
	_, err = sdk.AccAddressFromBech32(contract)
	if err != nil {
		return 0, nil
	}

	h.ibcHooksKeeper.StorePacketCallback(ctx, sourceChannel, seq, contract)
	return seq, nil
}

func (h WasmHooks) OnAcknowledgementPacketOverride(im IBCMiddleware, ctx sdk.Context, packet channeltypes.Packet, acknowledgement []byte, relayer sdk.AccAddress) error {
	err := im.App.OnAcknowledgementPacket(ctx, packet, acknowledgement, relayer)
	if err != nil {
		return err
	}

	if !h.ProperlyConfigured() {
		// Not configured. Return from the underlying implementation
		return nil
	}

	contract := h.ibcHooksKeeper.GetPacketCallback(ctx, packet.GetSourceChannel(), packet.GetSequence())
	if contract == "" {
		// No callback configured
		return nil
	}

	contractAddr, err := sdk.AccAddressFromBech32(contract)
	if err != nil {
		return errors.Wrap(err, "Ack callback error") // The callback configured is not a bech32. Error out
	}

	success := "false"
	if !IsJsonAckError(acknowledgement) {
		success = "true"
	}

	// Notify the sender that the ack has been received
	ackAsJson, err := json.Marshal(acknowledgement)
	if err != nil {
		// If the ack is not a json object, error
		return err
	}

	sudoMsg := []byte(fmt.Sprintf(
		`{"ibc_lifecycle_complete": {"ibc_ack": {"channel": "%s", "sequence": %d, "ack": %s, "success": %s}}}`,
		packet.SourceChannel, packet.Sequence, ackAsJson, success))
	_, err = h.ContractKeeper.Sudo(ctx, contractAddr, sudoMsg)
	if err != nil {
		// error processing the callback
		// ToDo: Open Question: Should we also delete the callback here?
		return errors.Wrap(err, "Ack callback error")
	}
	h.ibcHooksKeeper.DeletePacketCallback(ctx, packet.GetSourceChannel(), packet.GetSequence())
	return nil
}

func (h WasmHooks) OnTimeoutPacketOverride(im IBCMiddleware, ctx sdk.Context, packet channeltypes.Packet, relayer sdk.AccAddress) error {
	err := im.App.OnTimeoutPacket(ctx, packet, relayer)
	if err != nil {
		return err
	}

	if !h.ProperlyConfigured() {
		// Not configured. Return from the underlying implementation
		return nil
	}

	contract := h.ibcHooksKeeper.GetPacketCallback(ctx, packet.GetSourceChannel(), packet.GetSequence())
	if contract == "" {
		// No callback configured
		return nil
	}

	contractAddr, err := sdk.AccAddressFromBech32(contract)
	if err != nil {
		return errors.Wrap(err, "Timeout callback error") // The callback configured is not a bech32. Error out
	}

	sudoMsg := []byte(fmt.Sprintf(
		`{"ibc_lifecycle_complete": {"ibc_timeout": {"channel": "%s", "sequence": %d}}}`,
		packet.SourceChannel, packet.Sequence))
	_, err = h.ContractKeeper.Sudo(ctx, contractAddr, sudoMsg)
	if err != nil {
		// error processing the callback. This could be because the contract doesn't implement the message type to
		// process the callback. Retrying this will not help, so we can delete the callback from storage.
		// Since the packet has timed out, we don't expect any other responses that may trigger the callback.
		ctx.EventManager().EmitEvents(sdk.Events{
			sdk.NewEvent(
				"ibc-timeout-callback-error",
				sdk.NewAttribute("contract", contractAddr.String()),
				sdk.NewAttribute("message", string(sudoMsg)),
				sdk.NewAttribute("error", err.Error()),
			),
		})
	}
	h.ibcHooksKeeper.DeletePacketCallback(ctx, packet.GetSourceChannel(), packet.GetSequence())
	return nil
}

// NewEmitErrorAcknowledgement creates a new error acknowledgement after having emitted an event with the
// details of the error.
func NewEmitErrorAcknowledgement(ctx sdk.Context, err error, errorContexts ...string) channeltypes.Acknowledgement {
	errorType := "ibc-acknowledgement-error"
	logger := ctx.Logger().With("module", errorType)

	attributes := make([]sdk.Attribute, len(errorContexts)+1)
	attributes[0] = sdk.NewAttribute("error", err.Error())
	for i, s := range errorContexts {
		attributes[i+1] = sdk.NewAttribute("error-context", s)
		logger.Error(fmt.Sprintf("error-context: %v", s))
	}

	ctx.EventManager().EmitEvents(sdk.Events{
		sdk.NewEvent(
			errorType,
			attributes...,
		),
	})

	return channeltypes.NewErrorAcknowledgement(err)
}

// IsJsonAckError checks an IBC acknowledgement to see if it's an error.
// This is a replacement for ack.Success() which is currently not working on some circumstances
func IsJsonAckError(acknowledgement []byte) bool {
	var ackErr channeltypes.Acknowledgement_Error
	if err := json.Unmarshal(acknowledgement, &ackErr); err == nil && len(ackErr.Error) > 0 {
		return true
	}
	return false
}

// MustExtractDenomFromPacketOnRecv takes a packet with a valid ICS20 token data in the Data field and returns the
// denom as represented in the local chain.
// If the data cannot be unmarshalled this function will panic
func MustExtractDenomFromPacketOnRecv(packet ibcexported.PacketI) string {
	var data transfertypes.FungibleTokenPacketData
	if err := json.Unmarshal(packet.GetData(), &data); err != nil {
		panic("unable to unmarshal ICS20 packet data")
	}

	var denom string
	if transfertypes.ReceiverChainIsSource(packet.GetSourcePort(), packet.GetSourceChannel(), data.Denom) {
		// remove prefix added by sender chain
		voucherPrefix := transfertypes.GetDenomPrefix(packet.GetSourcePort(), packet.GetSourceChannel())

		unprefixedDenom := data.Denom[len(voucherPrefix):]

		// coin denomination used in sending from the escrow address
		denom = unprefixedDenom

		// The denomination used to send the coins is either the native denom or the hash of the path
		// if the denomination is not native.
		denomTrace := transfertypes.ParseDenomTrace(unprefixedDenom)
		if denomTrace.Path != "" {
			denom = denomTrace.IBCDenom()
		}
	} else {
		prefixedDenom := transfertypes.GetDenomPrefix(packet.GetDestPort(), packet.GetDestChannel()) + data.Denom
		denom = transfertypes.ParseDenomTrace(prefixedDenom).IBCDenom()
	}
	return denom
}