user: fix password info JSON encoding to survive round trips

PasswordInfos are marshaled when storing them in the database as
part of the local connector. However, the custom unmarsheler
defined could not unmarshal the standard marshling of this struct.

Add a struct tag to the Password field to correct this.

Closes #332

connector/config_repo_test.go

@@ -61,7 +61,7 @@ func TestNewConnectorConfigFromMap(t *testing.T) {
 				"type": "local",
 				"id":   "foo",
 				"passwordInfos": []map[string]string{
-					{"userId": "abc", "passwordHash": "PING"},
+					{"userId": "abc", "passwordHash": "UElORw=="}, // []byte is base64 encoded when using json.Marshasl
 					{"userId": "271", "passwordPlaintext": "pong"},
 				},
 			},

user/password.go

@@ -53,9 +53,9 @@ func NewPasswordFromPlaintext(plaintext string) (Password, error) {
 type PasswordInfo struct {
 	UserID string
 
-	Password Password
+	Password Password `json:"passwordHash"`
 
-	PasswordExpires time.Time
+	PasswordExpires time.Time `json:"passwordExpires"`
 }
 
 func (p PasswordInfo) Authenticate(plaintext string) (*oidc.Identity, error) {
@@ -86,7 +86,7 @@ type PasswordInfoRepo interface {
 func (u *PasswordInfo) UnmarshalJSON(data []byte) error {
 	var dec struct {
 		UserID            string    `json:"userId"`
-		PasswordHash      string    `json:"passwordHash"`
+		PasswordHash      []byte    `json:"passwordHash"`
 		PasswordPlaintext string    `json:"passwordPlaintext"`
 		PasswordExpires   time.Time `json:"passwordExpires"`
 	}
@@ -98,7 +98,9 @@ func (u *PasswordInfo) UnmarshalJSON(data []byte) error {
 
 	u.UserID = dec.UserID
 
-	u.PasswordExpires = dec.PasswordExpires
+	if !dec.PasswordExpires.IsZero() {
+		u.PasswordExpires = dec.PasswordExpires
+	}
 
 	if len(dec.PasswordHash) != 0 {
 		if dec.PasswordPlaintext != "" {

user/password_test.go

@@ -1,6 +1,7 @@
 package user
 
 import (
+	"encoding/json"
 	"net/url"
 	"testing"
 	"time"
@@ -13,6 +14,44 @@ import (
 	"github.com/coreos/go-oidc/key"
 )
 
+func TestPasswordMarshaling(t *testing.T) {
+	hashPassword := func(s string) []byte {
+		data, err := DefaultPasswordHasher(s)
+		if err != nil {
+			t.Fatalf("Failed to hash password: %v", err)
+		}
+		return data
+	}
+
+	tests := []PasswordInfo{
+		{
+			UserID:   "mrpink",
+			Password: hashPassword("mrpinks-password"),
+		},
+		{
+			UserID:          "mrorange",
+			Password:        hashPassword("mroranges-password"),
+			PasswordExpires: time.Now().Add(time.Hour),
+		},
+	}
+	for i, tt := range tests {
+		data, err := json.Marshal(tt)
+		if err != nil {
+			t.Errorf("case %d: failed to marshal password info: %v", i, err)
+			continue
+		}
+		var p PasswordInfo
+		if err := json.Unmarshal(data, &p); err != nil {
+			t.Errorf("case %d: failed to unmarshal password info: %v", i, err)
+			continue
+		}
+		if diff := pretty.Compare(tt, p); diff != "" {
+			t.Errorf("case %d: password info did not survive JSON marshal round trip: %s", i, diff)
+		}
+	}
+
+}
+
 func TestNewPasswordFromHash(t *testing.T) {
 	tests := []string{
 		"test",