[1/3] loopd: add TLS

README.md

@@ -333,6 +333,18 @@ pending swaps after a restart.
 Information about pending swaps is stored persistently in the swap database.
 Its location is `~/.loopd/<network>/loop.db`.
 
+## Transport security
+
+The gRPC and REST connections of `loopd` are encrypted with TLS the same way
+`lnd` is.
+
+If no custom loop directory is set then the TLS certificate is stored in
+`~/.loopd/<network>/tls.cert`.
+
+The `loop` command will pick up the file automatically on mainnet if no custom
+loop directory is used. For other networks it should be sufficient to add the
+`--network` flag to tell the CLI in what sub directory to look for the files.
+
 ## Multiple Simultaneous Swaps
 
 It is possible to execute multiple swaps simultaneously. Just keep loopd 

cmd/loop/main.go

@@ -6,15 +6,20 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"path/filepath"
 	"strconv"
+	"strings"
 	"time"
 
+	"github.com/lightninglabs/lndclient"
 	"github.com/lightninglabs/loop"
+	"github.com/lightninglabs/loop/loopd"
 	"github.com/lightninglabs/loop/looprpc"
 	"github.com/lightninglabs/loop/swap"
 	"github.com/lightninglabs/protobuf-hex-display/json"
 	"github.com/lightninglabs/protobuf-hex-display/jsonpb"
 	"github.com/lightninglabs/protobuf-hex-display/proto"
+	"github.com/lightningnetwork/lnd/lncfg"
 	"github.com/lightningnetwork/lnd/macaroons"
 
 	"github.com/btcsuite/btcutil"
@@ -43,10 +48,22 @@ var (
 	// that we set when sending it over the line.
 	defaultMacaroonTimeout int64 = 60
 
+	loopDirFlag = cli.StringFlag{
+		Name:  "loopdir",
+		Value: loopd.LoopDirBase,
+		Usage: "path to loop's base directory",
+	}
+	networkFlag = cli.StringFlag{
+		Name: "network, n",
+		Usage: "the network loop is running on e.g. mainnet, " +
+			"testnet, etc.",
+		Value: loopd.DefaultNetwork,
+	}
+
 	tlsCertFlag = cli.StringFlag{
-		Name: "tlscertpath",
-		Usage: "path to loop's TLS certificate, only needed if loop " +
-			"runs in the same process as lnd",
+		Name:  "tlscertpath",
+		Usage: "path to loop's TLS certificate",
+		Value: loopd.DefaultTLSCertPath,
 	}
 	macaroonPathFlag = cli.StringFlag{
 		Name: "macaroonpath",
@@ -103,6 +120,8 @@ func main() {
 			Value: "localhost:11010",
 			Usage: "loopd daemon address host:port",
 		},
+		networkFlag,
+		loopDirFlag,
 		tlsCertFlag,
 		macaroonPathFlag,
 	}
@@ -121,8 +140,10 @@ func main() {
 
 func getClient(ctx *cli.Context) (looprpc.SwapClientClient, func(), error) {
 	rpcServer := ctx.GlobalString("rpcserver")
-	tlsCertPath := ctx.GlobalString(tlsCertFlag.Name)
-	macaroonPath := ctx.GlobalString(macaroonPathFlag.Name)
+	tlsCertPath, macaroonPath, err := extractPathArgs(ctx)
+	if err != nil {
+		return nil, nil, err
+	}
 	conn, err := getClientConn(rpcServer, tlsCertPath, macaroonPath)
 	if err != nil {
 		return nil, nil, err
@@ -137,6 +158,40 @@ func getMaxRoutingFee(amt btcutil.Amount) btcutil.Amount {
 	return swap.CalcFee(amt, maxRoutingFeeBase, maxRoutingFeeRate)
 }
 
+// extractPathArgs parses the TLS certificate and macaroon paths from the
+// command.
+func extractPathArgs(ctx *cli.Context) (string, string, error) {
+	// We'll start off by parsing the network. This is needed to determine
+	// the correct path to the TLS certificate and macaroon when not
+	// specified.
+	networkStr := strings.ToLower(ctx.GlobalString("network"))
+	_, err := lndclient.Network(networkStr).ChainParams()
+	if err != nil {
+		return "", "", err
+	}
+
+	// We'll now fetch the loopdir so we can make a decision on how to
+	// properly read the cert. This will either be the default, or will have
+	// been overwritten by the end user.
+	loopDir := lncfg.CleanAndExpandPath(ctx.GlobalString(loopDirFlag.Name))
+	tlsCertPath := lncfg.CleanAndExpandPath(ctx.GlobalString(
+		tlsCertFlag.Name,
+	))
+
+	// If a custom lnd directory was set, we'll also check if custom paths
+	// for the TLS cert file were set as well. If not, we'll override their
+	// paths so they can be found within the custom loop directory set. This
+	// allows us to set a custom lnd directory, along with custom paths to
+	// the TLS cert file.
+	if loopDir != loopd.LoopDirBase || networkStr != loopd.DefaultNetwork {
+		tlsCertPath = filepath.Join(
+			loopDir, networkStr, loopd.DefaultTLSCertFilename,
+		)
+	}
+
+	return tlsCertPath, ctx.GlobalString(macaroonPathFlag.Name), nil
+}
+
 type inLimits struct {
 	maxMinerFee btcutil.Amount
 	maxSwapFee  btcutil.Amount
@@ -322,49 +377,44 @@ func getClientConn(address, tlsCertPath, macaroonPath string) (*grpc.ClientConn,
 		grpc.WithDefaultCallOptions(maxMsgRecvSize),
 	}
 
-	switch {
-	// If a TLS certificate file is specified, we need to load it and build
-	// transport credentials with it.
-	case tlsCertPath != "":
-		creds, err := credentials.NewClientTLSFromFile(tlsCertPath, "")
-		if err != nil {
-			fatal(err)
-		}
+	// TLS cannot be disabled, we'll always have a cert file to read.
+	creds, err := credentials.NewClientTLSFromFile(tlsCertPath, "")
+	if err != nil {
+		return nil, err
+	}
 
-		// Macaroons are only allowed to be transmitted over a TLS
-		// enabled connection.
-		if macaroonPath != "" {
-			opts = append(opts, readMacaroon(macaroonPath))
+	// Macaroons are not yet enabled by default.
+	if macaroonPath != "" {
+		macOption, err := readMacaroon(macaroonPath)
+		if err != nil {
+			return nil, err
 		}
-
-		opts = append(opts, grpc.WithTransportCredentials(creds))
-
-	// By default, if no certificate is supplied, we assume the RPC server
-	// runs without TLS.
-	default:
-		opts = append(opts, grpc.WithInsecure())
+		opts = append(opts, macOption)
 	}
 
+	opts = append(opts, grpc.WithTransportCredentials(creds))
+
 	conn, err := grpc.Dial(address, opts...)
 	if err != nil {
-		return nil, fmt.Errorf("unable to connect to RPC server: %v", err)
+		return nil, fmt.Errorf("unable to connect to RPC server: %v",
+			err)
 	}
 
 	return conn, nil
 }
 
 // readMacaroon tries to read the macaroon file at the specified path and create
 // gRPC dial options from it.
-func readMacaroon(macPath string) grpc.DialOption {
+func readMacaroon(macPath string) (grpc.DialOption, error) {
 	// Load the specified macaroon file.
 	macBytes, err := ioutil.ReadFile(macPath)
 	if err != nil {
-		fatal(fmt.Errorf("unable to read macaroon path : %v", err))
+		return nil, fmt.Errorf("unable to read macaroon path : %v", err)
 	}
 
 	mac := &macaroon.Macaroon{}
 	if err = mac.UnmarshalBinary(macBytes); err != nil {
-		fatal(fmt.Errorf("unable to decode macaroon: %v", err))
+		return nil, fmt.Errorf("unable to decode macaroon: %v", err)
 	}
 
 	macConstraints := []macaroons.Constraint{
@@ -384,10 +434,10 @@ func readMacaroon(macPath string) grpc.DialOption {
 	// Apply constraints to the macaroon.
 	constrainedMac, err := macaroons.AddConstraints(mac, macConstraints...)
 	if err != nil {
-		fatal(err)
+		return nil, err
 	}
 
 	// Now we append the macaroon credentials to the dial options.
 	cred := macaroons.NewMacaroonCredential(constrainedMac)
-	return grpc.WithPerRPCCredentials(cred)
+	return grpc.WithPerRPCCredentials(cred), nil
 }

go.mod

@@ -13,6 +13,7 @@ require (
 	github.com/lightninglabs/lndclient v0.11.0-0
 	github.com/lightninglabs/protobuf-hex-display v1.3.3-0.20191212020323-b444784ce75d
 	github.com/lightningnetwork/lnd v0.11.0-beta
+	github.com/lightningnetwork/lnd/cert v1.0.3
 	github.com/lightningnetwork/lnd/queue v1.0.4
 	github.com/stretchr/testify v1.5.1
 	github.com/urfave/cli v1.20.0

go.sum

@@ -182,6 +182,8 @@ github.com/lightningnetwork/lightning-onion v1.0.2-0.20200501022730-3c8c8d0b89ea
 github.com/lightningnetwork/lnd v0.11.0-beta h1:pUAT7FMHqS+iarNxyRtgj96XKCGAWwmb6ZdiUBy78ts=
 github.com/lightningnetwork/lnd v0.11.0-beta/go.mod h1:CzArvT7NFDLhVyW06+NJWSuWFmE6Ea+AjjA3txUBqTM=
 github.com/lightningnetwork/lnd/cert v1.0.2/go.mod h1:fmtemlSMf5t4hsQmcprSoOykypAPp+9c+0d0iqTScMo=
+github.com/lightningnetwork/lnd/cert v1.0.3 h1:/K2gjzLgVI8we2IIPKc0ztWTEa85uds5sWXi1K6mOT0=
+github.com/lightningnetwork/lnd/cert v1.0.3/go.mod h1:3MWXVLLPI0Mg0XETm9fT4N9Vyy/8qQLmaM5589bEggM=
 github.com/lightningnetwork/lnd/clock v1.0.1 h1:QQod8+m3KgqHdvVMV+2DRNNZS1GRFir8mHZYA+Z2hFo=
 github.com/lightningnetwork/lnd/clock v1.0.1/go.mod h1:KnQudQ6w0IAMZi1SgvecLZQZ43ra2vpDNj7H/aasemg=
 github.com/lightningnetwork/lnd/queue v1.0.1 h1:jzJKcTy3Nj5lQrooJ3aaw9Lau3I0IwvQR5sqtjdv2R0=