[GITEA] add option for banning dots in usernames

Refs: https://codeberg.org/forgejo/forgejo/pulls/676

Author:    Panagiotis "Ivory" Vasilopoulos <git@n0toose.net>
Date:      Mon Jun 12 13:57:01 2023 +0200

Co-authored-by: Gusted <postmaster@gusted.xyz>
(cherry picked from commit fabdda5c6e)
(cherry picked from commit d2c7f45621)
(cherry picked from commit dfdbaba3d6)
(cherry picked from commit a3cda092b8)
(cherry picked from commit f0fdb5905c)
(cherry picked from commit 9697e48c1f)
(cherry picked from commit 46e31009a8)
(cherry picked from commit 5bb2c54b6f)
(cherry picked from commit 682f9d24e1)
(cherry picked from commit 1863481005)
(cherry picked from commit 4f1b7c4ddb)
(cherry picked from commit 6afe70bbf1)
(cherry picked from commit 5cec1d9c2d)

Conflicts:
	templates/admin/config.tmpl
	https://codeberg.org/forgejo/forgejo/pulls/1512
(cherry picked from commit de2d172473)
(cherry picked from commit 37a3172dd9)
(cherry picked from commit 92dfca0c5a)
(cherry picked from commit a713d59b0c)
(cherry picked from commit e7bd71a618)
(cherry picked from commit 69f3e952c4)
(cherry picked from commit 83fbb7b566)
(cherry picked from commit 3196605fa9)
(cherry picked from commit e37eb8de9c)
(cherry picked from commit 8c99f59e48)
(cherry picked from commit 74aa1ac66f)
(cherry picked from commit 622440b3bd)
(cherry picked from commit 2c1ec90984)
(cherry picked from commit 24d57152e0)
(cherry picked from commit 071e9013f3)
(cherry picked from commit 27fbb726fa)
(cherry picked from commit 29eddd86ea)

custom/conf/app.example.ini

@@ -817,6 +817,11 @@ LEVEL = Info
 ;; Every new user will have restricted permissions depending on this setting
 ;DEFAULT_USER_IS_RESTRICTED = false
 ;;
+;; Users will be able to use dots when choosing their username. Disabling this is
+;; helpful if your usersare having issues with e.g. RSS feeds or advanced third-party
+;; extensions that use strange regex patterns.
+; ALLOW_DOTS_IN_USERNAMES = true
+;;
 ;; Either "public", "limited" or "private", default is "public"
 ;; Limited is for users visible only to signed users
 ;; Private is for users visible only to members of their organizations

modules/setting/service.go

@@ -68,6 +68,7 @@ var Service = struct {
 	DefaultKeepEmailPrivate                 bool
 	DefaultAllowCreateOrganization          bool
 	DefaultUserIsRestricted                 bool
+	AllowDotsInUsernames                    bool
 	EnableTimetracking                      bool
 	DefaultEnableTimetracking               bool
 	DefaultEnableDependencies               bool
@@ -180,6 +181,7 @@ func loadServiceFrom(rootCfg ConfigProvider) {
 	Service.DefaultKeepEmailPrivate = sec.Key("DEFAULT_KEEP_EMAIL_PRIVATE").MustBool()
 	Service.DefaultAllowCreateOrganization = sec.Key("DEFAULT_ALLOW_CREATE_ORGANIZATION").MustBool(true)
 	Service.DefaultUserIsRestricted = sec.Key("DEFAULT_USER_IS_RESTRICTED").MustBool(false)
+	Service.AllowDotsInUsernames = sec.Key("ALLOW_DOTS_IN_USERNAMES").MustBool(true)
 	Service.EnableTimetracking = sec.Key("ENABLE_TIMETRACKING").MustBool(true)
 	if Service.EnableTimetracking {
 		Service.DefaultEnableTimetracking = sec.Key("DEFAULT_ENABLE_TIMETRACKING").MustBool(true)

modules/validation/helpers.go

@@ -117,13 +117,20 @@ func IsValidExternalTrackerURLFormat(uri string) bool {
 }
 
 var (
-	validUsernamePattern   = regexp.MustCompile(`^[\da-zA-Z][-.\w]*$`)
-	invalidUsernamePattern = regexp.MustCompile(`[-._]{2,}|[-._]$`) // No consecutive or trailing non-alphanumeric chars
+	validUsernamePatternWithDots    = regexp.MustCompile(`^[\da-zA-Z][-.\w]*$`)
+	validUsernamePatternWithoutDots = regexp.MustCompile(`^[\da-zA-Z][-\w]*$`)
+
+	// No consecutive or trailing non-alphanumeric chars, catches both cases
+	invalidUsernamePattern = regexp.MustCompile(`[-._]{2,}|[-._]$`)
 )
 
 // IsValidUsername checks if username is valid
 func IsValidUsername(name string) bool {
 	// It is difficult to find a single pattern that is both readable and effective,
 	// but it's easier to use positive and negative checks.
-	return validUsernamePattern.MatchString(name) && !invalidUsernamePattern.MatchString(name)
+	if setting.Service.AllowDotsInUsernames {
+		return validUsernamePatternWithDots.MatchString(name) && !invalidUsernamePattern.MatchString(name)
+	}
+
+	return validUsernamePatternWithoutDots.MatchString(name) && !invalidUsernamePattern.MatchString(name)
 }

modules/validation/helpers_test.go

@@ -155,7 +155,8 @@ func Test_IsValidExternalTrackerURLFormat(t *testing.T) {
 	}
 }
 
-func TestIsValidUsername(t *testing.T) {
+func TestIsValidUsernameAllowDots(t *testing.T) {
+	setting.Service.AllowDotsInUsernames = true
 	tests := []struct {
 		arg  string
 		want bool
@@ -185,3 +186,31 @@ func TestIsValidUsername(t *testing.T) {
 		})
 	}
 }
+
+func TestIsValidUsernameBanDots(t *testing.T) {
+	setting.Service.AllowDotsInUsernames = false
+	defer func() {
+		setting.Service.AllowDotsInUsernames = true
+	}()
+
+	tests := []struct {
+		arg  string
+		want bool
+	}{
+		{arg: "a", want: true},
+		{arg: "abc", want: true},
+		{arg: "0.b-c", want: false},
+		{arg: "a.b-c_d", want: false},
+		{arg: ".abc", want: false},
+		{arg: "abc.", want: false},
+		{arg: "a..bc", want: false},
+		{arg: "a...bc", want: false},
+		{arg: "a.-bc", want: false},
+		{arg: "a._bc", want: false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.arg, func(t *testing.T) {
+			assert.Equalf(t, tt.want, IsValidUsername(tt.arg), "IsValidUsername[AllowDotsInUsernames=false](%v)", tt.arg)
+		})
+	}
+}

modules/web/middleware/binding.go

@@ -8,6 +8,7 @@ import (
 	"reflect"
 	"strings"
 
+	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/translation"
 	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/modules/validation"
@@ -135,7 +136,11 @@ func Validate(errs binding.Errors, data map[string]any, f Form, l translation.Lo
 			case validation.ErrRegexPattern:
 				data["ErrorMsg"] = trName + l.Tr("form.regex_pattern_error", errs[0].Message)
 			case validation.ErrUsername:
-				data["ErrorMsg"] = trName + l.Tr("form.username_error")
+				if setting.Service.AllowDotsInUsernames {
+					data["ErrorMsg"] = trName + l.Tr("form.username_error")
+				} else {
+					data["ErrorMsg"] = trName + l.Tr("form.username_error_no_dots")
+				}
 			case validation.ErrInvalidGroupTeamMap:
 				data["ErrorMsg"] = trName + l.Tr("form.invalid_group_team_map_error", errs[0].Message)
 			default:

templates/admin/config.tmpl

@@ -157,6 +157,8 @@
 				<dd>{{if .Service.DefaultKeepEmailPrivate}}{{svg "octicon-check"}}{{else}}{{svg "octicon-x"}}{{end}}</dd>
 				<dt>{{ctx.Locale.Tr "admin.config.default_allow_create_organization"}}</dt>
 				<dd>{{if .Service.DefaultAllowCreateOrganization}}{{svg "octicon-check"}}{{else}}{{svg "octicon-x"}}{{end}}</dd>
+				<dt>{{ctx.Locale.Tr "admin.config.allow_dots_in_usernames"}}</dt>
+				<dd>{{if .Service.AllowDotsInUsernames}}{{svg "octicon-check"}}{{else}}{{svg "octicon-x"}}{{end}}</dd>
 				<dt>{{ctx.Locale.Tr "admin.config.enable_timetracking"}}</dt>
 				<dd>{{if .Service.EnableTimetracking}}{{svg "octicon-check"}}{{else}}{{svg "octicon-x"}}{{end}}</dd>
 				{{if .Service.EnableTimetracking}}