Merge pull request #968 from ellemouton/sql10Sessions2

[sql-10] sessions: decouple super macaroon helpers from `sessions` package

Author: ellemouton

accounts/rpcserver.go

@@ -8,7 +8,7 @@ import (
 
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/lightninglabs/lightning-terminal/litrpc"
-	"github.com/lightninglabs/lightning-terminal/session"
+	litmac "github.com/lightninglabs/lightning-terminal/macaroons"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/macaroons"
@@ -22,12 +22,12 @@ type RPCServer struct {
 
 	service *InterceptorService
 
-	superMacBaker session.MacaroonBaker
+	superMacBaker litmac.Baker
 }
 
 // NewRPCServer returns a new RPC server for the given service.
 func NewRPCServer(service *InterceptorService,
-	superMacBaker session.MacaroonBaker) *RPCServer {
+	superMacBaker litmac.Baker) *RPCServer {
 
 	return &RPCServer{
 		service:       service,
@@ -79,19 +79,17 @@ func (s *RPCServer) CreateAccount(ctx context.Context,
 
 	var rootKeyIdSuffix [4]byte
 	copy(rootKeyIdSuffix[:], account.ID[0:4])
-	macRootKey := session.NewSuperMacaroonRootKeyID(rootKeyIdSuffix)
+	macRootKey := litmac.NewSuperMacaroonRootKeyID(rootKeyIdSuffix)
 
 	accountCaveat := checkers.Condition(
 		macaroons.CondLndCustom,
 		fmt.Sprintf("%s %x", CondAccount, account.ID[:]),
 	)
 
-	macHex, err := s.superMacBaker(ctx, macRootKey, &session.MacaroonRecipe{
-		Permissions: MacaroonPermissions,
-		Caveats: []macaroon.Caveat{{
-			Id: []byte(accountCaveat),
-		}},
-	})
+	macHex, err := s.superMacBaker(
+		ctx, macRootKey, MacaroonPermissions,
+		[]macaroon.Caveat{{Id: []byte(accountCaveat)}},
+	)
 	if err != nil {
 		return nil, fmt.Errorf("error baking account macaroon: %w", err)
 	}

cmd/litcli/helpers.go

@@ -7,7 +7,7 @@ import (
 	"encoding/json"
 	"os"
 
-	"github.com/lightninglabs/lightning-terminal/session"
+	"github.com/lightninglabs/lightning-terminal/macaroons"
 	"github.com/urfave/cli"
 )
 
@@ -66,7 +66,7 @@ func superMacRootKey(ctx *cli.Context) error {
 		}
 	}
 
-	id := session.NewSuperMacaroonRootKeyID(suffix)
+	id := macaroons.NewSuperMacaroonRootKeyID(suffix)
 
 	printJSON(struct {
 		RootKeyID uint64 `json:"root_key_id"`
@@ -97,7 +97,7 @@ var isSuperMacaroonCmd = cli.Command{
 // isSuperMacaroon checks if the users given macaroon is considered a super
 // macaroon.
 func isSuperMacaroon(ctx *cli.Context) error {
-	isSuperMac := session.IsSuperMacaroon(ctx.String("mac"))
+	isSuperMac := macaroons.IsSuperMacaroon(ctx.String("mac"))
 
 	printJSON(struct {
 		IsSuperMacaroon bool `json:"is_super_macaroon"`

itest/litd_firewall_test.go

@@ -22,6 +22,7 @@ import (
 	"github.com/lightninglabs/lightning-terminal/firewall"
 	"github.com/lightninglabs/lightning-terminal/firewalldb"
 	"github.com/lightninglabs/lightning-terminal/litrpc"
+	"github.com/lightninglabs/lightning-terminal/macaroons"
 	"github.com/lightninglabs/lightning-terminal/rules"
 	"github.com/lightninglabs/lightning-terminal/session"
 	"github.com/lightningnetwork/lnd"
@@ -2566,7 +2567,7 @@ func (c *caveatCredentials) GetRequestMetadata(ctx context.Context,
 		return metadata, nil
 	}
 
-	mac, err := session.ParseMacaroon(macHex)
+	mac, err := macaroons.ParseMacaroon(macHex)
 	if err != nil {
 		return nil, err
 	}

macaroons/macaroons.go

@@ -0,0 +1,35 @@
+package macaroons
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+
+	"github.com/lightningnetwork/lnd/lnrpc"
+	"google.golang.org/protobuf/proto"
+	"gopkg.in/macaroon-bakery.v2/bakery"
+	"gopkg.in/macaroon.v2"
+)
+
+// Baker is a function type for baking a super macaroon.
+type Baker func(ctx context.Context, rootKeyID uint64,
+	perms []bakery.Op, caveats []macaroon.Caveat) (string, error)
+
+// RootKeyIDFromMacaroon extracts the root key ID of the passed macaroon.
+func RootKeyIDFromMacaroon(mac *macaroon.Macaroon) (uint64, error) {
+	rawID := mac.Id()
+	if rawID[0] != byte(bakery.LatestVersion) {
+		return 0, fmt.Errorf("mac id is not on the latest version")
+	}
+
+	decodedID := &lnrpc.MacaroonId{}
+	idProto := rawID[1:]
+	err := proto.Unmarshal(idProto, decodedID)
+	if err != nil {
+		return 0, err
+	}
+
+	// The storage ID is a string representation of a 64-bit unsigned
+	// number.
+	return strconv.ParseUint(string(decodedID.StorageId), 10, 64)
+}

macaroons/super_mac.go

@@ -0,0 +1,120 @@
+package macaroons
+
+import (
+	"bytes"
+	"context"
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+
+	"github.com/lightningnetwork/lnd/lnrpc"
+	"gopkg.in/macaroon-bakery.v2/bakery"
+	"gopkg.in/macaroon.v2"
+)
+
+// SuperMacaroonRootKeyPrefix is the prefix we set on a super macaroon's root
+// key to clearly mark it as such.
+var SuperMacaroonRootKeyPrefix = [4]byte{0xFF, 0xEE, 0xDD, 0xCC}
+
+// SuperMacaroonValidator is a function type for validating a super macaroon.
+type SuperMacaroonValidator func(ctx context.Context,
+	superMacaroon []byte, requiredPermissions []bakery.Op,
+	fullMethod string) error
+
+// NewSuperMacaroonRootKeyID returns a new macaroon root key ID that has the
+// prefix to mark it as a super macaroon root key.
+func NewSuperMacaroonRootKeyID(id [4]byte) uint64 {
+	rootKeyBytes := make([]byte, 8)
+	copy(rootKeyBytes[:], SuperMacaroonRootKeyPrefix[:])
+	copy(rootKeyBytes[4:], id[:])
+
+	return binary.BigEndian.Uint64(rootKeyBytes)
+}
+
+// ParseMacaroon parses a hex encoded macaroon into its native struct.
+func ParseMacaroon(macHex string) (*macaroon.Macaroon, error) {
+	macBytes, err := hex.DecodeString(macHex)
+	if err != nil {
+		return nil, err
+	}
+
+	mac := &macaroon.Macaroon{}
+	if err := mac.UnmarshalBinary(macBytes); err != nil {
+		return nil, err
+	}
+
+	return mac, nil
+}
+
+// IsSuperMacaroon returns true if the given hex encoded macaroon is a super
+// macaroon baked by LiT which can be identified by its root key ID.
+func IsSuperMacaroon(macHex string) bool {
+	mac, err := ParseMacaroon(macHex)
+	if err != nil {
+		return false
+	}
+
+	rootKeyID, err := RootKeyIDFromMacaroon(mac)
+	if err != nil {
+		return false
+	}
+
+	return isSuperMacaroonRootKeyID(rootKeyID)
+}
+
+// isSuperMacaroonRootKeyID returns true if the given macaroon root key ID (also
+// known as storage ID) is a super macaroon, which can be identified by its
+// first 4 bytes.
+func isSuperMacaroonRootKeyID(rootKeyID uint64) bool {
+	rootKeyBytes := make([]byte, 8)
+	binary.BigEndian.PutUint64(rootKeyBytes, rootKeyID)
+	return bytes.HasPrefix(rootKeyBytes, SuperMacaroonRootKeyPrefix[:])
+}
+
+// BakeSuperMacaroon uses the lnd client to bake a macaroon that can include
+// permissions for multiple daemons.
+func BakeSuperMacaroon(ctx context.Context, lnd lnrpc.LightningClient,
+	rootKeyID uint64, perms []bakery.Op, caveats []macaroon.Caveat) (string,
+	error) {
+
+	if lnd == nil {
+		return "", errors.New("lnd not yet connected")
+	}
+
+	req := &lnrpc.BakeMacaroonRequest{
+		Permissions: make(
+			[]*lnrpc.MacaroonPermission, len(perms),
+		),
+		AllowExternalPermissions: true,
+		RootKeyId:                rootKeyID,
+	}
+	for idx, perm := range perms {
+		req.Permissions[idx] = &lnrpc.MacaroonPermission{
+			Entity: perm.Entity,
+			Action: perm.Action,
+		}
+	}
+
+	res, err := lnd.BakeMacaroon(ctx, req)
+	if err != nil {
+		return "", err
+	}
+
+	mac, err := ParseMacaroon(res.Macaroon)
+	if err != nil {
+		return "", err
+	}
+
+	for _, caveat := range caveats {
+		if err := mac.AddFirstPartyCaveat(caveat.Id); err != nil {
+			return "", err
+		}
+	}
+
+	macBytes, err := mac.MarshalBinary()
+	if err != nil {
+		return "", err
+	}
+
+	return hex.EncodeToString(macBytes), err
+}

session/macaroon_test.go renamed to macaroons/super_mac_test.go

@@ -1,4 +1,4 @@
-package session
+package macaroons
 
 import (
 	"testing"
@@ -25,13 +25,21 @@ var (
 		"60a6caf"
 )
 
+// TestSuperMacaroonRootKeyID tests that adding the super macaroon prefix to
+// a root key ID results in a valid super macaroon root key ID.
 func TestSuperMacaroonRootKeyID(t *testing.T) {
+	t.Parallel()
+
 	someBytes := [4]byte{02, 03, 44, 88}
 	rootKeyID := NewSuperMacaroonRootKeyID(someBytes)
 	require.True(t, isSuperMacaroonRootKeyID(rootKeyID))
 	require.False(t, isSuperMacaroonRootKeyID(123))
 }
 
+// TestIsSuperMacaroon tests that we can correctly identify an example super
+// macaroon.
 func TestIsSuperMacaroon(t *testing.T) {
+	t.Parallel()
+
 	require.True(t, IsSuperMacaroon(testMacHex))
 }

rpc_proxy.go

@@ -13,8 +13,8 @@ import (
 
 	"github.com/improbable-eng/grpc-web/go/grpcweb"
 	"github.com/lightninglabs/lightning-terminal/litrpc"
+	litmac "github.com/lightninglabs/lightning-terminal/macaroons"
 	"github.com/lightninglabs/lightning-terminal/perms"
-	"github.com/lightninglabs/lightning-terminal/session"
 	litstatus "github.com/lightninglabs/lightning-terminal/status"
 	"github.com/lightninglabs/lightning-terminal/subservers"
 	"github.com/lightningnetwork/lnd/lncfg"
@@ -71,7 +71,7 @@ func (e *proxyErr) Unwrap() error {
 // or REST request and delegate (and convert if necessary) it to the correct
 // component.
 func newRpcProxy(cfg *Config, validator macaroons.MacaroonValidator,
-	superMacValidator session.SuperMacaroonValidator,
+	superMacValidator litmac.SuperMacaroonValidator,
 	permsMgr *perms.Manager, subServerMgr *subservers.Manager,
 	statusMgr *litstatus.Manager, getLNDClient lndBasicClientFn) *rpcProxy {
 
@@ -176,7 +176,7 @@ type rpcProxy struct {
 	bakeSuperMac bakeSuperMac
 
 	macValidator      macaroons.MacaroonValidator
-	superMacValidator session.SuperMacaroonValidator
+	superMacValidator litmac.SuperMacaroonValidator
 
 	superMacaroon string
 
@@ -331,7 +331,9 @@ func (p *rpcProxy) makeDirector(allowLitRPC bool) func(ctx context.Context,
 				))
 			}
 
-		case len(macHeader) == 1 && session.IsSuperMacaroon(macHeader[0]):
+		case len(macHeader) == 1 &&
+			litmac.IsSuperMacaroon(macHeader[0]):
+
 			// If we have a macaroon, and it's a super macaroon,
 			// then we need to convert it into the actual daemon
 			// macaroon if they're running in remote mode.

session/interface.go

@@ -1,12 +1,12 @@
 package session
 
 import (
-	"context"
 	"fmt"
 	"time"
 
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightninglabs/lightning-node-connect/mailbox"
+	"github.com/lightninglabs/lightning-terminal/macaroons"
 	"gopkg.in/macaroon-bakery.v2/bakery"
 	"gopkg.in/macaroon.v2"
 )
@@ -71,10 +71,6 @@ type Session struct {
 	GroupID ID
 }
 
-// MacaroonBaker is a function type for baking a super macaroon.
-type MacaroonBaker func(ctx context.Context, rootKeyID uint64,
-	recipe *MacaroonRecipe) (string, error)
-
 // NewSession creates a new session with the given user-defined parameters.
 func NewSession(id ID, localPrivKey *btcec.PrivateKey, label string, typ Type,
 	expiry time.Time, serverAddr string, devServer bool, perms []bakery.Op,
@@ -86,7 +82,7 @@ func NewSession(id ID, localPrivKey *btcec.PrivateKey, label string, typ Type,
 		return nil, fmt.Errorf("error deriving pairing secret: %v", err)
 	}
 
-	macRootKey := NewSuperMacaroonRootKeyID(id)
+	macRootKey := macaroons.NewSuperMacaroonRootKeyID(id)
 
 	// The group ID will by default be the same as the Session ID
 	// unless this session links to a previous session.