feat: restrict languages (#6931)

* feat: return 404 or 409 if org reg disallowed

* fix: system limit permissions

* feat: add iam limits api

* feat: disallow public org registrations on default instance

* add integration test

* test: integration

* fix test

* docs: describe public org registrations

* avoid updating docs deps

* fix system limits integration test

* silence integration tests

* fix linting

* ignore strange linter complaints

* review

* improve reset properties naming

* redefine the api

* use restrictions aggregate

* test query

* simplify and test projection

* test commands

* fix unit tests

* move integration test

* support restrictions on default instance

* also test GetRestrictions

* self review

* lint

* abstract away resource owner

* fix tests

* configure supported languages

* fix allowed languages

* fix tests

* default lang must not be restricted

* preferred language must be allowed

* change preferred languages

* check languages everywhere

* lint

* test command side

* lint

* add integration test

* add integration test

* restrict supported ui locales

* lint

* lint

* cleanup

* lint

* allow undefined preferred language

* fix integration tests

* update main

* fix env var

* ignore linter

* ignore linter

* improve integration test config

* reduce cognitive complexity

* compile

* check for duplicates

* remove useless restriction checks

* review

* revert restriction renaming

* fix language restrictions

* lint

* generate

* allow custom texts for supported langs for now

* fix tests

* cleanup

* cleanup

* cleanup

* lint

* unsupported preferred lang is allowed

* fix integration test

* finish reverting to old property name

* finish reverting to old property name

* load languages

* refactor(i18n): centralize translators and fs

* lint

* amplify no validations on preferred languages

* fix integration test

* lint

* fix resetting allowed languages

* test unchanged restrictions

internal/api/oidc/server.go

@@ -12,6 +12,7 @@ import (
 	"github.com/zitadel/zitadel/internal/auth/repository"
 	"github.com/zitadel/zitadel/internal/command"
 	"github.com/zitadel/zitadel/internal/crypto"
+	"github.com/zitadel/zitadel/internal/i18n"
 	"github.com/zitadel/zitadel/internal/query"
 	"github.com/zitadel/zitadel/internal/telemetry/tracing"
 )
@@ -103,8 +104,15 @@ func (s *Server) Ready(ctx context.Context, r *op.Request[struct{}]) (_ *op.Resp
 func (s *Server) Discovery(ctx context.Context, r *op.Request[struct{}]) (_ *op.Response, err error) {
 	ctx, span := tracing.NewSpan(ctx)
 	defer func() { span.EndWithError(err) }()
-
-	return op.NewResponse(s.createDiscoveryConfig(ctx)), nil
+	restrictions, err := s.query.GetInstanceRestrictions(ctx)
+	if err != nil {
+		return nil, err
+	}
+	allowedLanguages := restrictions.AllowedLanguages
+	if len(allowedLanguages) == 0 {
+		allowedLanguages = i18n.SupportedLanguages()
+	}
+	return op.NewResponse(s.createDiscoveryConfig(ctx, allowedLanguages)), nil
 }
 
 func (s *Server) Keys(ctx context.Context, r *op.Request[struct{}]) (_ *op.Response, err error) {
@@ -205,7 +213,7 @@ func (s *Server) EndSession(ctx context.Context, r *op.Request[oidc.EndSessionRe
 	return s.LegacyServer.EndSession(ctx, r)
 }
 
-func (s *Server) createDiscoveryConfig(ctx context.Context) *oidc.DiscoveryConfiguration {
+func (s *Server) createDiscoveryConfig(ctx context.Context, supportedUILocales oidc.Locales) *oidc.DiscoveryConfiguration {
 	issuer := op.IssuerFromContext(ctx)
 	return &oidc.DiscoveryConfiguration{
 		Issuer:                                     issuer,
@@ -231,7 +239,7 @@ func (s *Server) createDiscoveryConfig(ctx context.Context) *oidc.DiscoveryConfi
 		RevocationEndpointAuthMethodsSupported:             op.AuthMethodsRevocationEndpoint(s.Provider()),
 		ClaimsSupported:                                    op.SupportedClaims(s.Provider()),
 		CodeChallengeMethodsSupported:                      op.CodeChallengeMethods(s.Provider()),
-		UILocalesSupported:                                 s.Provider().SupportedUILocales(),
+		UILocalesSupported:                                 supportedUILocales,
 		RequestParameterSupported:                          s.Provider().RequestObjectSupported(),
 	}
 }