Fix API leaking Usermail if not logged in (go-gitea#25097)

The API should only return the real Mail of a User, if the caller is
logged in. The check do to this don't work. This PR fixes this. This not
really a security issue, but can lead to Spam.

---------

Co-authored-by: silverwind <me@silverwind.io>

models/user/user.go

@@ -203,11 +203,16 @@ func UpdateUserTheme(u *User, themeName string) error {
 	return UpdateUserCols(db.DefaultContext, u, "theme")
 }
 
+// GetPlaceholderEmail returns an noreply email
+func (u *User) GetPlaceholderEmail() string {
+	return fmt.Sprintf("%s@%s", u.LowerName, setting.Service.NoReplyAddress)
+}
+
 // GetEmail returns an noreply email, if the user has set to keep his
 // email address private, otherwise the primary email address.
 func (u *User) GetEmail() string {
 	if u.KeepEmailPrivate {
-		return fmt.Sprintf("%s@%s", u.LowerName, setting.Service.NoReplyAddress)
+		return u.GetPlaceholderEmail()
 	}
 	return u.Email
 }

services/convert/user.go

@@ -51,7 +51,7 @@ func toUser(ctx context.Context, user *user_model.User, signed, authed bool) *ap
 		ID:          user.ID,
 		UserName:    user.Name,
 		FullName:    user.FullName,
-		Email:       user.GetEmail(),
+		Email:       user.GetPlaceholderEmail(),
 		AvatarURL:   user.AvatarLink(ctx),
 		Created:     user.CreatedUnix.AsTime(),
 		Restricted:  user.IsRestricted,

tests/integration/api_user_info_test.go

@@ -9,6 +9,8 @@ import (
 	"testing"
 
 	auth_model "code.gitea.io/gitea/models/auth"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
 	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/tests"
 
@@ -21,6 +23,8 @@ func TestAPIUserInfo(t *testing.T) {
 	user := "user1"
 	user2 := "user31"
 
+	user3 := unittest.AssertExistsAndLoadBean(t, &user_model.User{Name: "user3"})
+
 	session := loginUser(t, user)
 	token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeReadUser)
 
@@ -36,6 +40,18 @@ func TestAPIUserInfo(t *testing.T) {
 
 		req = NewRequest(t, "GET", fmt.Sprintf("/api/v1/users/%s", user2))
 		MakeRequest(t, req, http.StatusNotFound)
+
+		// test if the placaholder Mail is returned if a User is not logged in
+		req = NewRequest(t, "GET", fmt.Sprintf("/api/v1/users/%s", user3.Name))
+		resp = MakeRequest(t, req, http.StatusOK)
+		DecodeJSON(t, resp, &u)
+		assert.Equal(t, user3.GetPlaceholderEmail(), u.Email)
+
+		// Test if the correct Mail is returned if a User is logged in
+		req = NewRequest(t, "GET", fmt.Sprintf("/api/v1/users/%s?token=%s", user3.Name, token))
+		resp = MakeRequest(t, req, http.StatusOK)
+		DecodeJSON(t, resp, &u)
+		assert.Equal(t, user3.GetEmail(), u.Email)
 	})
 
 	t.Run("GetAuthenticatedUser", func(t *testing.T) {

tests/integration/api_user_search_test.go

@@ -4,14 +4,12 @@
 package integration
 
 import (
-	"fmt"
 	"net/http"
 	"testing"
 
 	auth_model "code.gitea.io/gitea/models/auth"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
-	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/tests"
 
@@ -54,11 +52,7 @@ func TestAPIUserSearchNotLoggedIn(t *testing.T) {
 	for _, user := range results.Data {
 		assert.Contains(t, user.UserName, query)
 		modelUser = unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: user.ID})
-		if modelUser.KeepEmailPrivate {
-			assert.EqualValues(t, fmt.Sprintf("%s@%s", modelUser.LowerName, setting.Service.NoReplyAddress), user.Email)
-		} else {
-			assert.EqualValues(t, modelUser.Email, user.Email)
-		}
+		assert.EqualValues(t, modelUser.GetPlaceholderEmail(), user.Email)
 	}
 }