Add Allow-/Block-List for Migrate & Mirrors (#13610)

* add black list and white list support for migrating repositories

* fix fmt

* fix lint

* fix vendor

* fix modules.txt

* clean diff

* specify log message

* use blocklist/allowlist

* allways use lowercase to match url

* Apply allow/block

* Settings: use existing "migrations" section

* convert domains lower case

* dont store unused value

* Block private addresses for migration by default

* fix lint

* use proposed-upstream func to detect private IP addr

* a nit

* add own error for blocked migration, add tests, imprufe api

* fix test

* fix-if-localhost-is-ipv4

* rename error & error message

* rename setting options

* Apply suggestions from code review

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

modules/setting/migrations.go

@@ -4,11 +4,18 @@
 
 package setting
 
+import (
+	"strings"
+)
+
 var (
 	// Migrations settings
 	Migrations = struct {
-		MaxAttempts  int
-		RetryBackoff int
+		MaxAttempts        int
+		RetryBackoff       int
+		AllowedDomains     []string
+		BlockedDomains     []string
+		AllowLocalNetworks bool
 	}{
 		MaxAttempts:  3,
 		RetryBackoff: 3,
@@ -19,4 +26,15 @@ func newMigrationsService() {
 	sec := Cfg.Section("migrations")
 	Migrations.MaxAttempts = sec.Key("MAX_ATTEMPTS").MustInt(Migrations.MaxAttempts)
 	Migrations.RetryBackoff = sec.Key("RETRY_BACKOFF").MustInt(Migrations.RetryBackoff)
+
+	Migrations.AllowedDomains = sec.Key("ALLOWED_DOMAINS").Strings(",")
+	for i := range Migrations.AllowedDomains {
+		Migrations.AllowedDomains[i] = strings.ToLower(Migrations.AllowedDomains[i])
+	}
+	Migrations.BlockedDomains = sec.Key("BLOCKED_DOMAINS").Strings(",")
+	for i := range Migrations.BlockedDomains {
+		Migrations.BlockedDomains[i] = strings.ToLower(Migrations.BlockedDomains[i])
+	}
+
+	Migrations.AllowLocalNetworks = sec.Key("ALLOW_LOCALNETWORKS").MustBool(false)
 }