loopout: reject unsupported address formats

This commit adds a check to reject unsupported address
formats such as P2PK or P2TR addresses

loopd/swapclient_server.go

@@ -55,6 +55,12 @@ var (
 	errBalanceTooLow = errors.New(
 		"channel balance too low for loop out amount",
 	)
+
+	// errInvalidAddress is returned when the destination address is of
+	// an unsupported format such as P2PK or P2TR addresses.
+	errInvalidAddress = errors.New(
+		"invalid or unsupported address",
+	)
 )
 
 // swapClientServer implements the grpc service exposed by loopd.
@@ -1154,6 +1160,18 @@ func validateLoopOutRequest(ctx context.Context, lnd lndclient.LightningClient,
 			errIncorrectChain, chainParams.Name)
 	}
 
+	// Check that the provided destination address is a supported
+	// address format.
+	switch sweepAddr.(type) {
+	case *btcutil.AddressWitnessScriptHash,
+		*btcutil.AddressWitnessPubKeyHash,
+		*btcutil.AddressScriptHash,
+		*btcutil.AddressPubKeyHash:
+
+	default:
+		return 0, errInvalidAddress
+	}
+
 	// Check that the label is valid.
 	if err := labels.Validate(req.Label); err != nil {
 		return 0, err

loopd/swapclient_server_test.go

@@ -26,6 +26,10 @@ var (
 		[]byte{123}, &chaincfg.MainNetParams,
 	)
 
+	nodepubkeyAddr, _ = btcutil.DecodeAddress(
+		mock_lnd.NewMockLnd().NodePubkey, &chaincfg.MainNetParams,
+	)
+
 	chanID1 = lnwire.NewShortChanIDFromInt(1)
 	chanID2 = lnwire.NewShortChanIDFromInt(2)
 	chanID3 = lnwire.NewShortChanIDFromInt(3)
@@ -445,6 +449,13 @@ func TestValidateLoopOutRequest(t *testing.T) {
 			err:            errBalanceTooLow,
 			expectedTarget: 0,
 		},
+		{
+			name:           "node pubkey as dest addr",
+			chain:          chaincfg.MainNetParams,
+			destAddr:       nodepubkeyAddr,
+			err:            errInvalidAddress,
+			expectedTarget: 0,
+		},
 	}
 
 	for _, test := range tests {