From af73b78bbb03ceb950ef73c0c3bb974b6da26488 Mon Sep 17 00:00:00 2001
From: Brad Davidson <brad.davidson@rancher.com>
Date: Mon, 1 Jul 2024 22:56:48 +0000
Subject: [PATCH] Fix ClusterRoleBinding subject growth

Fixed an issue where failing to include APIGroup on the subjects caused the reconcile helpers to think the subject needed to be re-added every time RKE2 starts up.

Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
---
 pkg/rke2/clusterrole.go           | 35 +++++++++++++++++++++++++++++++
 pkg/rke2/clusterrole_bootstrap.go |  4 ++--
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/pkg/rke2/clusterrole.go b/pkg/rke2/clusterrole.go
index 543fa28279..bc2bc110e2 100644
--- a/pkg/rke2/clusterrole.go
+++ b/pkg/rke2/clusterrole.go
@@ -2,11 +2,16 @@ package rke2
 
 import (
 	"context"
+	"encoding/json"
 	"sync"
 
 	"github.com/k3s-io/k3s/pkg/cli/cmds"
 	"github.com/sirupsen/logrus"
+	rbacv1 "k8s.io/api/rbac/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
 	genericapiserver "k8s.io/apiserver/pkg/server"
+	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/tools/clientcmd"
 	rbacrest "k8s.io/kubernetes/pkg/registry/rbac/rest"
 )
@@ -21,6 +26,10 @@ func setClusterRoles() cmds.StartupHook {
 			logrus.Info("Applying Cluster Role Bindings")
 
 			config, err := clientcmd.BuildConfigFromFlags("", args.KubeConfigSupervisor)
+			if err != nil {
+				logrus.Fatalf("clusterrole: new k8s restConfig: %v", err)
+			}
+			client, err := kubernetes.NewForConfig(config)
 			if err != nil {
 				logrus.Fatalf("clusterrole: new k8s client: %v", err)
 			}
@@ -45,6 +54,32 @@ func setClusterRoles() cmds.StartupHook {
 				logrus.Fatalf("clusterrole: EnsureRBACPolicy failed: %v", err)
 			}
 
+			// Begin remediation for https://github.com/rancher/rke2/issues/6272
+			// This can be removed after ~1 year of shipping releases not affected by this issue.
+
+			// stub binding/clusterrolebinding for marshalling the patch json
+			type binding struct {
+				Subjects []rbacv1.Subject `json:"subjects"`
+			}
+
+			// It is not critical if these fail, the excess subjects just need to be cleaned up eventually
+			for ns, rbs := range policy.RoleBindings {
+				for _, rb := range rbs {
+					b, _ := json.Marshal(binding{Subjects: rb.Subjects})
+					if _, err := client.RbacV1().RoleBindings(ns).Patch(ctx, rb.Name, types.MergePatchType, b, metav1.PatchOptions{}); err != nil {
+						logrus.Debugf("Failed to patch RoleBinding %s/%s subjects: %v", ns, rb.Name, err)
+					}
+				}
+			}
+			for _, crb := range policy.ClusterRoleBindings {
+				b, _ := json.Marshal(binding{Subjects: crb.Subjects})
+				if _, err := client.RbacV1().ClusterRoleBindings().Patch(ctx, crb.Name, types.MergePatchType, b, metav1.PatchOptions{}); err != nil {
+					logrus.Debugf("Failed to patch ClusterRoleBinding %s subjects: %v", crb.Name, err)
+				}
+			}
+
+			// End remediation for https://github.com/rancher/rke2/issues/6272
+
 			logrus.Info("Cluster Role Bindings applied successfully")
 		}()
 		return nil
diff --git a/pkg/rke2/clusterrole_bootstrap.go b/pkg/rke2/clusterrole_bootstrap.go
index b023536283..5268789a3f 100644
--- a/pkg/rke2/clusterrole_bootstrap.go
+++ b/pkg/rke2/clusterrole_bootstrap.go
@@ -102,7 +102,7 @@ func roleBindings() map[string][]rbacv1.RoleBinding {
 // For some reason the core helpers don't have any methods for adding namespaced users, only namespaced service accounts.
 func RoleBindingNamespacedUsers(r *rbacv1helpers.RoleBindingBuilder, namespace string, users ...string) *rbacv1helpers.RoleBindingBuilder {
 	for _, user := range users {
-		r.RoleBinding.Subjects = append(r.RoleBinding.Subjects, rbacv1.Subject{Kind: rbacv1.UserKind, Namespace: namespace, Name: user})
+		r.RoleBinding.Subjects = append(r.RoleBinding.Subjects, rbacv1.Subject{APIGroup: rbacv1.GroupName, Kind: rbacv1.UserKind, Namespace: namespace, Name: user})
 	}
 	return r
 }
@@ -119,7 +119,7 @@ func RoleBindingName(r *rbacv1helpers.RoleBindingBuilder, name string) *rbacv1he
 // For some reason the core helpers don't have any methods for adding namespaced users, only namespaced service accounts.
 func ClusterRoleBindingNamespacedUsers(r *rbacv1helpers.ClusterRoleBindingBuilder, namespace string, users ...string) *rbacv1helpers.ClusterRoleBindingBuilder {
 	for _, user := range users {
-		r.ClusterRoleBinding.Subjects = append(r.ClusterRoleBinding.Subjects, rbacv1.Subject{Kind: rbacv1.UserKind, Namespace: namespace, Name: user})
+		r.ClusterRoleBinding.Subjects = append(r.ClusterRoleBinding.Subjects, rbacv1.Subject{APIGroup: rbacv1.GroupName, Kind: rbacv1.UserKind, Namespace: namespace, Name: user})
 	}
 	return r
 }