feat: add _URI entries for mail config (#8116)

For the mailer and incoming_mailer config, allow passwords to be read from a file.
Add `_URI` config values and use the existing `loadSecret` function to do this.

Resolves https://codeberg.org/forgejo/forgejo/issues/8113

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/8116
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Reviewed-by: oliverpool <oliverpool@noreply.codeberg.org>
Co-authored-by: fruzitent <fruzit@gmail.com>
Co-committed-by: fruzitent <fruzit@gmail.com>

custom/conf/app.example.ini

@@ -1768,6 +1768,9 @@ LEVEL = Info
 ;; Use PASSWD = `your password` for quoting if you use special characters in the password.
 ;PASSWD =
 ;;
+;; Alternative location to specify mailer password. You cannot specify both this and PASSWD, and must pick one
+;PASSWD_URI = file:/etc/forgejo/mailer_passwd
+;;
 ;; Send mails only in plain text, without HTML alternative
 ;SEND_AS_PLAIN_TEXT = false
 ;;
@@ -1820,6 +1823,9 @@ LEVEL = Info
 ;; Password of the receiving account
 ;PASSWORD =
 ;;
+;; Alternative location to specify password of the receiving account. You cannot specify both this and PASSWORD, and must pick one
+;PASSWORD_URI = file:/etc/forgejo/email_incoming_password
+;;
 ;; Whether the IMAP server uses TLS.
 ;USE_TLS = false
 ;;

modules/setting/incoming_email.go

@@ -44,9 +44,14 @@ func loadIncomingEmailFrom(rootCfg ConfigProvider) {
 	if sec.HasKey("USER") && !sec.HasKey("USERNAME") {
 		IncomingEmail.Username = sec.Key("USER").String()
 	}
+
 	if sec.HasKey("PASSWD") && !sec.HasKey("PASSWORD") {
-		IncomingEmail.Password = sec.Key("PASSWD").String()
+		sec.Key("PASSWORD").SetValue(sec.Key("PASSWD").String())
 	}
+	if sec.HasKey("PASSWD_URI") && !sec.HasKey("PASSWORD_URI") {
+		sec.Key("PASSWORD_URI").SetValue(sec.Key("PASSWD_URI").String())
+	}
+	IncomingEmail.Password = loadSecret(sec, "PASSWORD_URI", "PASSWORD")
 
 	// Infer Port if not set
 	if IncomingEmail.Port == 0 {

modules/setting/incoming_email_test.go

@@ -4,6 +4,8 @@
 package setting
 
 import (
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -35,6 +37,22 @@ func Test_loadIncomingEmailFrom(t *testing.T) {
 		assert.Equal(t, "y0u'll n3v3r gUess th1S!!1", IncomingEmail.Password)
 	})
 
+	t.Run("Secrets", func(t *testing.T) {
+		uri := filepath.Join(t.TempDir(), "email_incoming_password")
+
+		if err := os.WriteFile(uri, []byte("th1S gUess n3v3r y0u'll!!1"), 0o644); err != nil {
+			t.Fatal(err)
+		}
+
+		cfg, sec := makeBaseConfig()
+		sec.NewKey("PASSWORD_URI", "file:"+uri)
+
+		IncomingEmail.Password = ""
+		loadIncomingEmailFrom(cfg)
+
+		assert.Equal(t, "th1S gUess n3v3r y0u'll!!1", IncomingEmail.Password)
+	})
+
 	t.Run("Port settings", func(t *testing.T) {
 		t.Run("no port, no tls", func(t *testing.T) {
 			defer resetIncomingEmailPort()()

modules/setting/mailer.go

@@ -147,6 +147,10 @@ func loadMailerFrom(rootCfg ConfigProvider) {
 	if sec.HasKey("PASSWORD") && !sec.HasKey("PASSWD") {
 		sec.Key("PASSWD").SetValue(sec.Key("PASSWORD").String())
 	}
+	if sec.HasKey("PASSWORD_URI") && !sec.HasKey("PASSWD_URI") {
+		sec.Key("PASSWD_URI").SetValue(sec.Key("PASSWORD_URI").String())
+	}
+	sec.Key("PASSWD").SetValue(loadSecret(sec, "PASSWD_URI", "PASSWD"))
 
 	// Set default values & validate
 	sec.Key("NAME").MustString(AppName)

modules/setting/mailer_test.go

@@ -4,6 +4,8 @@
 package setting
 
 import (
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -52,6 +54,24 @@ func Test_loadMailerFrom(t *testing.T) {
 		assert.Equal(t, "y0u'll n3v3r gUess th1S!!1", MailService.Passwd)
 	})
 
+	t.Run("Secrets", func(t *testing.T) {
+		uri := filepath.Join(t.TempDir(), "mailer_passwd")
+
+		if err := os.WriteFile(uri, []byte("th1S gUess n3v3r y0u'll!!1"), 0o644); err != nil {
+			t.Fatal(err)
+		}
+
+		cfg, _ := NewConfigProviderFromData("")
+		sec := cfg.Section("mailer")
+		sec.NewKey("ENABLED", "true")
+		sec.NewKey("PASSWD_URI", "file:"+uri)
+
+		MailService.Passwd = ""
+		loadMailerFrom(cfg)
+
+		assert.Equal(t, "th1S gUess n3v3r y0u'll!!1", MailService.Passwd)
+	})
+
 	t.Run("sendmail argument sanitization", func(t *testing.T) {
 		cfg, _ := NewConfigProviderFromData("")
 		sec := cfg.Section("mailer")