chore: OpenVPN user and password as nullable

- Username and password can be the empty string for custom provider

internal/configuration/settings/openvpn.go

@@ -19,13 +19,15 @@ type OpenVPN struct {
 	// It can only be "2.4" or "2.5".
 	Version string
 	// User is the OpenVPN authentication username.
-	// It cannot be an empty string in the internal state
-	// if OpenVPN is used.
-	User string
+	// It cannot be nil in the internal state if OpenVPN is used.
+	// It is usually required but in some cases can be the empty string
+	// to indicate no user+password authentication is needed.
+	User *string
 	// Password is the OpenVPN authentication password.
-	// It cannot be an empty string in the internal state
-	// if OpenVPN is used.
-	Password string
+	// It cannot be nil in the internal state if OpenVPN is used.
+	// It is usually required but in some cases can be the empty string
+	// to indicate no user+password authentication is needed.
+	Password *string
 	// ConfFile is a custom OpenVPN configuration file path.
 	// It can be set to the empty string for it to be ignored.
 	// It cannot be nil in the internal state.
@@ -88,14 +90,14 @@ func (o OpenVPN) validate(vpnProvider string) (err error) {
 
 	isCustom := vpnProvider == providers.Custom
 
-	if !isCustom && o.User == "" {
+	if !isCustom && *o.User == "" {
 		return ErrOpenVPNUserIsEmpty
 	}
 
 	passwordRequired := !isCustom &&
-		(vpnProvider != providers.Ivpn || !ivpnAccountID.MatchString(o.User))
+		(vpnProvider != providers.Ivpn || !ivpnAccountID.MatchString(*o.User))
 
-	if passwordRequired && o.Password == "" {
+	if passwordRequired && *o.Password == "" {
 		return ErrOpenVPNPasswordIsEmpty
 	}
 
@@ -204,8 +206,8 @@ func validateOpenVPNClientKey(vpnProvider, clientKey string) (err error) {
 func (o *OpenVPN) copy() (copied OpenVPN) {
 	return OpenVPN{
 		Version:      o.Version,
-		User:         o.User,
-		Password:     o.Password,
+		User:         helpers.CopyStringPtr(o.User),
+		Password:     helpers.CopyStringPtr(o.Password),
 		ConfFile:     helpers.CopyStringPtr(o.ConfFile),
 		Ciphers:      helpers.CopyStringSlice(o.Ciphers),
 		Auth:         helpers.CopyStringPtr(o.Auth),
@@ -225,8 +227,8 @@ func (o *OpenVPN) copy() (copied OpenVPN) {
 // unset field of the receiver settings object.
 func (o *OpenVPN) mergeWith(other OpenVPN) {
 	o.Version = helpers.MergeWithString(o.Version, other.Version)
-	o.User = helpers.MergeWithString(o.User, other.User)
-	o.Password = helpers.MergeWithString(o.Password, other.Password)
+	o.User = helpers.MergeWithStringPtr(o.User, other.User)
+	o.Password = helpers.MergeWithStringPtr(o.Password, other.Password)
 	o.ConfFile = helpers.MergeWithStringPtr(o.ConfFile, other.ConfFile)
 	o.Ciphers = helpers.MergeStringSlices(o.Ciphers, other.Ciphers)
 	o.Auth = helpers.MergeWithStringPtr(o.Auth, other.Auth)
@@ -246,8 +248,8 @@ func (o *OpenVPN) mergeWith(other OpenVPN) {
 // settings.
 func (o *OpenVPN) overrideWith(other OpenVPN) {
 	o.Version = helpers.OverrideWithString(o.Version, other.Version)
-	o.User = helpers.OverrideWithString(o.User, other.User)
-	o.Password = helpers.OverrideWithString(o.Password, other.Password)
+	o.User = helpers.OverrideWithStringPtr(o.User, other.User)
+	o.Password = helpers.OverrideWithStringPtr(o.Password, other.Password)
 	o.ConfFile = helpers.OverrideWithStringPtr(o.ConfFile, other.ConfFile)
 	o.Ciphers = helpers.OverrideWithStringSlice(o.Ciphers, other.Ciphers)
 	o.Auth = helpers.OverrideWithStringPtr(o.Auth, other.Auth)
@@ -264,8 +266,11 @@ func (o *OpenVPN) overrideWith(other OpenVPN) {
 
 func (o *OpenVPN) setDefaults(vpnProvider string) {
 	o.Version = helpers.DefaultString(o.Version, openvpn.Openvpn25)
+	o.User = helpers.DefaultStringPtr(o.User, "")
 	if vpnProvider == providers.Mullvad {
-		o.Password = "m"
+		o.Password = helpers.DefaultStringPtr(o.Password, "m")
+	} else {
+		o.Password = helpers.DefaultStringPtr(o.Password, "")
 	}
 
 	o.ConfFile = helpers.DefaultStringPtr(o.ConfFile, "")
@@ -293,8 +298,8 @@ func (o OpenVPN) String() string {
 func (o OpenVPN) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("OpenVPN settings:")
 	node.Appendf("OpenVPN version: %s", o.Version)
-	node.Appendf("User: %s", helpers.ObfuscatePassword(o.User))
-	node.Appendf("Password: %s", helpers.ObfuscatePassword(o.Password))
+	node.Appendf("User: %s", helpers.ObfuscatePassword(*o.User))
+	node.Appendf("Password: %s", helpers.ObfuscatePassword(*o.Password))
 
 	if *o.ConfFile != "" {
 		node.Appendf("Custom configuration file: %s", *o.ConfFile)

internal/configuration/sources/env/openvpn.go

@@ -72,14 +72,25 @@ func (r *Reader) readOpenVPN() (
 	return openVPN, nil
 }
 
-func (r *Reader) readOpenVPNUser() (user string) {
-	_, user = r.getEnvWithRetro("OPENVPN_USER", "USER")
+func (r *Reader) readOpenVPNUser() (user *string) {
+	user = new(string)
+	_, *user = r.getEnvWithRetro("OPENVPN_USER", "USER")
+	if *user == "" {
+		return nil
+	}
+
 	// Remove spaces in user ID to simplify user's life, thanks @JeordyR
-	return strings.ReplaceAll(user, " ", "")
+	*user = strings.ReplaceAll(*user, " ", "")
+	return user
 }
 
-func (r *Reader) readOpenVPNPassword() (password string) {
-	_, password = r.getEnvWithRetro("OPENVPN_PASSWORD", "PASSWORD")
+func (r *Reader) readOpenVPNPassword() (password *string) {
+	password = new(string)
+	_, *password = r.getEnvWithRetro("OPENVPN_PASSWORD", "PASSWORD")
+	if *password == "" {
+		return nil
+	}
+
 	return password
 }
 

internal/configuration/sources/secrets/helpers.go

@@ -25,18 +25,3 @@ func readSecretFileAsStringPtr(secretPathEnvKey, defaultSecretPath string) (
 	}
 	return files.ReadFromFile(path)
 }
-
-func readSecretFileAsString(secretPathEnvKey, defaultSecretPath string) (
-	s string, err error) {
-	path := getCleanedEnv(secretPathEnvKey)
-	if path == "" {
-		path = defaultSecretPath
-	}
-	stringPtr, err := files.ReadFromFile(path)
-	if err != nil {
-		return "", err
-	} else if stringPtr == nil {
-		return "", nil
-	}
-	return *stringPtr, nil
-}

internal/configuration/sources/secrets/openvpn.go

@@ -8,7 +8,7 @@ import (
 
 func readOpenVPN() (
 	settings settings.OpenVPN, err error) {
-	settings.User, err = readSecretFileAsString(
+	settings.User, err = readSecretFileAsStringPtr(
 		"OPENVPN_USER_SECRETFILE",
 		"/run/secrets/openvpn_user",
 	)
@@ -16,7 +16,7 @@ func readOpenVPN() (
 		return settings, fmt.Errorf("cannot read user file: %w", err)
 	}
 
-	settings.Password, err = readSecretFileAsString(
+	settings.Password, err = readSecretFileAsStringPtr(
 		"OPENVPN_PASSWORD_SECRETFILE",
 		"/run/secrets/openvpn_password",
 	)

internal/provider/custom/openvpnconf.go

@@ -74,7 +74,7 @@ func modifyConfig(lines []string, connection models.Connection,
 	modified = append(modified, "pull-filter ignore \"auth-token\"") // prevent auth failed loop
 	modified = append(modified, "auth-retry nointeract")
 	modified = append(modified, "suppress-timestamps")
-	if settings.User != "" {
+	if *settings.User != "" {
 		modified = append(modified, "auth-user-pass "+openvpn.AuthConf)
 	}
 	modified = append(modified, "verb "+strconv.Itoa(*settings.Verbosity))

internal/provider/custom/openvpnconf_test.go

@@ -36,7 +36,7 @@ func Test_modifyConfig(t *testing.T) {
 				"auth bla",
 			},
 			settings: settings.OpenVPN{
-				User:        "user",
+				User:        stringPtr("user"),
 				Ciphers:     []string{"cipher"},
 				Auth:        stringPtr("auth"),
 				MSSFix:      uint16Ptr(1000),

internal/server/helpers.go

@@ -0,0 +1,3 @@
+package server
+
+func stringPtr(s string) *string { return &s }

internal/server/openvpn.go

@@ -94,8 +94,8 @@ func (h *openvpnHandler) setStatus(w http.ResponseWriter, r *http.Request) {
 func (h *openvpnHandler) getSettings(w http.ResponseWriter) {
 	vpnSettings := h.looper.GetSettings()
 	settings := vpnSettings.OpenVPN
-	settings.User = "redacted"
-	settings.Password = "redacted"
+	settings.User = stringPtr("redacted")
+	settings.Password = stringPtr("redacted")
 	encoder := json.NewEncoder(w)
 	if err := encoder.Encode(settings); err != nil {
 		h.warner.Warn(err.Error())

internal/vpn/openvpn.go

@@ -27,8 +27,8 @@ func setupOpenVPN(ctx context.Context, fw Firewall,
 		return nil, "", fmt.Errorf("failed writing configuration to file: %w", err)
 	}
 
-	if settings.OpenVPN.User != "" {
-		err := openvpnConf.WriteAuthFile(settings.OpenVPN.User, settings.OpenVPN.Password)
+	if *settings.OpenVPN.User != "" {
+		err := openvpnConf.WriteAuthFile(*settings.OpenVPN.User, *settings.OpenVPN.Password)
 		if err != nil {
 			return nil, "", fmt.Errorf("failed writing auth to file: %w", err)
 		}