[SECURITY] Notify users about account security changes

- Currently if the password, primary mail, TOTP or security keys are
changed, no notification is made of that and makes compromising an
account a bit easier as it's essentially undetectable until the original
person tries to log in. Although other changes should be made as
well (re-authing before allowing a password change), this should go a
long way of improving the account security in Forgejo.
- Adds a mail notification for password and primary mail changes. For
the primary mail change, a mail notification is sent to the old primary
mail.
- Add a mail notification when TOTP or a security keys is removed, if no
other 2FA method is configured the mail will also contain that 2FA is
no longer needed to log into their account.
- `MakeEmailAddressPrimary` is refactored to the user service package,
as it now involves calling the mailer service.
- Unit tests added.
- Integration tests added.

models/user/email_address.go

@@ -307,60 +307,6 @@ func updateActivation(ctx context.Context, email *EmailAddress, activate bool) e
 	return UpdateUserCols(ctx, user, "rands")
 }
 
-func MakeEmailPrimaryWithUser(ctx context.Context, user *User, email *EmailAddress) error {
-	ctx, committer, err := db.TxContext(ctx)
-	if err != nil {
-		return err
-	}
-	defer committer.Close()
-	sess := db.GetEngine(ctx)
-
-	// 1. Update user table
-	user.Email = email.Email
-	if _, err = sess.ID(user.ID).Cols("email").Update(user); err != nil {
-		return err
-	}
-
-	// 2. Update old primary email
-	if _, err = sess.Where("uid=? AND is_primary=?", email.UID, true).Cols("is_primary").Update(&EmailAddress{
-		IsPrimary: false,
-	}); err != nil {
-		return err
-	}
-
-	// 3. update new primary email
-	email.IsPrimary = true
-	if _, err = sess.ID(email.ID).Cols("is_primary").Update(email); err != nil {
-		return err
-	}
-
-	return committer.Commit()
-}
-
-// MakeEmailPrimary sets primary email address of given user.
-func MakeEmailPrimary(ctx context.Context, email *EmailAddress) error {
-	has, err := db.GetEngine(ctx).Get(email)
-	if err != nil {
-		return err
-	} else if !has {
-		return ErrEmailAddressNotExist{Email: email.Email}
-	}
-
-	if !email.IsActivated {
-		return ErrEmailNotActivated
-	}
-
-	user := &User{}
-	has, err = db.GetEngine(ctx).ID(email.UID).Get(user)
-	if err != nil {
-		return err
-	} else if !has {
-		return ErrUserNotExist{UID: email.UID}
-	}
-
-	return MakeEmailPrimaryWithUser(ctx, user, email)
-}
-
 // VerifyActiveEmailCode verifies active email code when active account
 func VerifyActiveEmailCode(ctx context.Context, code, email string) *EmailAddress {
 	if user := GetVerifyUser(ctx, code); user != nil {

models/user/email_address_test.go

@@ -43,40 +43,6 @@ func TestIsEmailUsed(t *testing.T) {
 	assert.False(t, isExist)
 }
 
-func TestMakeEmailPrimary(t *testing.T) {
-	assert.NoError(t, unittest.PrepareTestDatabase())
-
-	email := &user_model.EmailAddress{
-		Email: "user567890@example.com",
-	}
-	err := user_model.MakeEmailPrimary(db.DefaultContext, email)
-	assert.Error(t, err)
-	assert.EqualError(t, err, user_model.ErrEmailAddressNotExist{Email: email.Email}.Error())
-
-	email = &user_model.EmailAddress{
-		Email: "user11@example.com",
-	}
-	err = user_model.MakeEmailPrimary(db.DefaultContext, email)
-	assert.Error(t, err)
-	assert.EqualError(t, err, user_model.ErrEmailNotActivated.Error())
-
-	email = &user_model.EmailAddress{
-		Email: "user9999999@example.com",
-	}
-	err = user_model.MakeEmailPrimary(db.DefaultContext, email)
-	assert.Error(t, err)
-	assert.True(t, user_model.IsErrUserNotExist(err))
-
-	email = &user_model.EmailAddress{
-		Email: "user101@example.com",
-	}
-	err = user_model.MakeEmailPrimary(db.DefaultContext, email)
-	assert.NoError(t, err)
-
-	user, _ := user_model.GetUserByID(db.DefaultContext, int64(10))
-	assert.Equal(t, "user101@example.com", user.Email)
-}
-
 func TestActivate(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 

models/user/user.go

@@ -451,17 +451,22 @@ var emailToReplacer = strings.NewReplacer(
 )
 
 // EmailTo returns a string suitable to be put into a e-mail `To:` header.
-func (u *User) EmailTo() string {
+func (u *User) EmailTo(overrideMail ...string) string {
 	sanitizedDisplayName := emailToReplacer.Replace(u.DisplayName())
 
-	// should be an edge case but nice to have
-	if sanitizedDisplayName == u.Email {
-		return u.Email
+	email := u.Email
+	if len(overrideMail) > 0 {
+		email = overrideMail[0]
 	}
 
-	address, err := mail.ParseAddress(fmt.Sprintf("%s <%s>", sanitizedDisplayName, u.Email))
+	// should be an edge case but nice to have
+	if sanitizedDisplayName == email {
+		return email
+	}
+
+	address, err := mail.ParseAddress(fmt.Sprintf("%s <%s>", sanitizedDisplayName, email))
 	if err != nil {
-		return u.Email
+		return email
 	}
 
 	return address.String()

models/user/user_test.go

@@ -625,6 +625,11 @@ func TestEmailTo(t *testing.T) {
 			assert.EqualValues(t, testCase.result, testUser.EmailTo())
 		})
 	}
+
+	t.Run("Override user's email", func(t *testing.T) {
+		testUser := &user_model.User{FullName: "Christine Jorgensen", Email: "christine@test.com"}
+		assert.EqualValues(t, `"Christine Jorgensen" <christine@example.org>`, testUser.EmailTo("christine@example.org"))
+	})
 }
 
 func TestDisabledUserFeatures(t *testing.T) {