Merge pull request #14 from vds/013-marshalbinary

Fix bugs in binary marshal/unmarshal code and add tests.

export_test.go

@@ -0,0 +1,6 @@
+package macaroon
+
+// Data returns the macaroon's data.
+func (m *Macaroon) Data() []byte {
+	return m.data
+}

macaroon.go

@@ -127,7 +127,7 @@ func (m *Macaroon) appendCaveat(caveatId string, verificationId []byte, loc stri
 		}
 	}
 	if loc != "" {
-		cav.location, ok = m.appendPacket(fieldLocation, []byte(loc))
+		cav.location, ok = m.appendPacket(fieldCaveatLocation, []byte(loc))
 		if !ok {
 			return nil, fmt.Errorf("caveat location too big")
 		}

macaroon_test.go

@@ -1,14 +1,14 @@
 package macaroon_test
 
 import (
+	"encoding/base64"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"testing"
 
 	"github.com/rogpeppe/macaroon"
 	gc "gopkg.in/check.v1"
-	_ "net/http"
 )
 
 func TestPackage(t *testing.T) {
@@ -485,3 +485,49 @@ func makeMacaroons(mspecs []macaroonSpec) (
 	}
 	return []byte(mspecs[0].rootKey), primary, discharges
 }
+
+func assertEqualMacaroons(c *gc.C, m0, m1 *macaroon.Macaroon) {
+	m0json, err := m0.MarshalJSON()
+	c.Assert(err, gc.IsNil)
+	m1json, err := m1.MarshalJSON()
+	var m0val, m1val interface{}
+	err = json.Unmarshal(m0json, &m0val)
+	c.Assert(err, gc.IsNil)
+	err = json.Unmarshal(m1json, &m1val)
+	c.Assert(err, gc.IsNil)
+	c.Assert(m0val, gc.DeepEquals, m1val)
+}
+
+func (*macaroonSuite) TestBinaryRoundTrip(c *gc.C) {
+	// Test the binary marshalling and unmarshalling of a macaroon with
+	// first and third party caveats.
+	rootKey := []byte("secret")
+	m0 := MustNew(rootKey, "some id", "a location")
+	err := m0.AddFirstPartyCaveat("first caveat")
+	c.Assert(err, gc.IsNil)
+	err = m0.AddFirstPartyCaveat("second caveat")
+	c.Assert(err, gc.IsNil)
+	err = m0.AddThirdPartyCaveat([]byte("shared root key"), "3rd party caveat", "remote.com")
+	c.Assert(err, gc.IsNil)
+	data, err := m0.MarshalBinary()
+	c.Assert(err, gc.IsNil)
+	var m1 macaroon.Macaroon
+	err = m1.UnmarshalBinary(data)
+	c.Assert(err, gc.IsNil)
+	assertEqualMacaroons(c, m0, &m1)
+}
+
+func (*macaroonSuite) TestBinaryMarshalingAgainstLibmacaroon(c *gc.C) {
+	// Test that a libmacaroon marshalled macaroon can be correctly unmarshaled
+	data, err := base64.StdEncoding.DecodeString(
+		"MDAxN2xvY2F0aW9uIHNvbWV3aGVyZQowMDEyaWRlbnRpZmllciBpZAowMDEzY2lkIGlkZW50aWZpZXIKMDA1MXZpZCAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAC4i9QwCgbL/wZGFvLQpsyhLOv0v6VjIo2KJv5miz+7krqCpt5EhmrL8pYO9xrhT80KMDAxM2NsIHRoaXJkIHBhcnR5CjAwMmZzaWduYXR1cmUg3BXkIDX0giAPPrgkDLbiMGYy/zsC2qPb4jU4G/dohkAK")
+	c.Assert(err, gc.IsNil)
+	var m0 macaroon.Macaroon
+	err = m0.UnmarshalBinary(data)
+	c.Assert(err, gc.IsNil)
+	jsonData := []byte(`{"caveats":[{"cid":"identifier\n","vid":"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAuIvUMAoGy/8GRhby0KbMoSzr9L+lYyKNiib+Zos/u5K6gqbeRIZqy/KWDvca4U/NCg==","cl":"third party\n"}],"location":"somewhere\n","identifier":"id\n","signature":"dc15e42035f482200f3eb8240cb6e2306632ff3b02daa3dbe235381bf76886400a"}`)
+	var m1 macaroon.Macaroon
+	err = m1.UnmarshalJSON(jsonData)
+	c.Assert(err, gc.IsNil)
+	assertEqualMacaroons(c, &m0, &m1)
+}

marshal.go

@@ -128,7 +128,6 @@ func (m *Macaroon) UnmarshalBinary(data []byte) error {
 	if err != nil {
 		return err
 	}
-
 	var cav caveat
 	for {
 		p, err := m.parsePacket(start)
@@ -142,6 +141,8 @@ func (m *Macaroon) UnmarshalBinary(data []byte) error {
 			if cav.caveatId.len() != 0 {
 				m.caveats = append(m.caveats, cav)
 			}
+			// Remove the signature from data.
+			m.data = m.data[0:p.start]
 			m.sig = append([]byte(nil), m.dataBytes(p)...)
 			return nil
 		case fieldCaveatId:
@@ -163,10 +164,11 @@ func (m *Macaroon) UnmarshalBinary(data []byte) error {
 			return fmt.Errorf("unexpected field %q", field)
 		}
 	}
+	return nil
 }
 
 func (m *Macaroon) expectPacket(start int, kind string) (int, packet, error) {
-	p, err := m.parsePacket(0)
+	p, err := m.parsePacket(start)
 	if err != nil {
 		return 0, packet{}, err
 	}