macaroons: add BakeFromRootKey function

macaroons/bake_test.go

@@ -0,0 +1,58 @@
+package macaroons_test
+
+import (
+	"context"
+	"encoding/hex"
+	"testing"
+
+	"github.com/lightningnetwork/lnd/macaroons"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc/metadata"
+	"gopkg.in/macaroon-bakery.v2/bakery"
+)
+
+// TestBakeFromRootKey tests that a macaroon can be baked from a root key
+// directly without needing to create a store or service first.
+func TestBakeFromRootKey(t *testing.T) {
+	// Create a test store and unlock it.
+	_, store := newTestStore(t)
+
+	pw := []byte("weks")
+	err := store.CreateUnlock(&pw)
+	require.NoError(t, err)
+
+	// Force the store to create a new random root key.
+	key, id, err := store.RootKey(defaultRootKeyIDContext)
+	require.NoError(t, err)
+	require.Len(t, key, 32)
+
+	tmpKey, err := store.Get(defaultRootKeyIDContext, id)
+	require.NoError(t, err)
+	require.Equal(t, key, tmpKey)
+
+	// Create a service that uses the root key store.
+	service, err := macaroons.NewService(store, "lnd", false)
+	require.NoError(t, err, "Error creating new service")
+	defer func() {
+		require.NoError(t, service.Close())
+	}()
+
+	// Call the BakeFromRootKey function that derives a macaroon directly
+	// from the root key.
+	perms := []bakery.Op{{Entity: "foo", Action: "bar"}}
+	mac, err := macaroons.BakeFromRootKey(key, perms)
+	require.NoError(t, err)
+
+	macaroonBytes, err := mac.MarshalBinary()
+	require.NoError(t, err)
+
+	md := metadata.New(map[string]string{
+		"macaroon": hex.EncodeToString(macaroonBytes),
+	})
+	macCtx := metadata.NewIncomingContext(context.Background(), md)
+
+	// The macaroon should be valid for the service, since the root key was
+	// the same.
+	err = service.ValidateMacaroon(macCtx, nil, "baz")
+	require.NoError(t, err)
+}