fix: add rolebinding validation against rfc-1123 dns for sa subjects

Signed-off-by: Oliver Bähler <oliverbaehler@hotmail.com>

controllers/tenant/rolebindings.go

@@ -97,6 +97,9 @@ func (r *Manager) syncAdditionalRoleBinding(tenant *capsulev1beta1.Tenant, ns st
 			r.Log.Error(err, "Cannot sync Additional RoleBinding")
 		}
 		r.Log.Info(fmt.Sprintf("Additional RoleBindings sync result: %s", string(res)), "name", target.Name, "namespace", target.Namespace)
+		if err != nil {
+			return
+		}
 	}
 
 	return nil

main.go

@@ -167,7 +167,7 @@ func main() {
 		route.PVC(pvc.Handler()),
 		route.Service(service.Handler()),
 		route.NetworkPolicy(utils.InCapsuleGroups(cfg, networkpolicy.Handler())),
-		route.Tenant(tenant.NameHandler(), tenant.IngressClassRegexHandler(), tenant.StorageClassRegexHandler(), tenant.ContainerRegistryRegexHandler(), tenant.HostnameRegexHandler(), tenant.FreezedEmitter(), tenant.ServiceAccountNameHandler()),
+		route.Tenant(tenant.NameHandler(), tenant.RoleBindingRegexHandler(), tenant.IngressClassRegexHandler(), tenant.StorageClassRegexHandler(), tenant.ContainerRegistryRegexHandler(), tenant.HostnameRegexHandler(), tenant.FreezedEmitter(), tenant.ServiceAccountNameHandler()),
 		route.OwnerReference(utils.InCapsuleGroups(cfg, ownerreference.Handler(cfg))),
 		route.Cordoning(tenant.CordoningHandler(cfg)),
 		route.Node(utils.InCapsuleGroups(cfg, node.UserMetadataHandler(cfg, kubeVersion))),

pkg/webhook/tenant/rolebindings_regex.go

@@ -0,0 +1,66 @@
+// Copyright 2020-2021 Clastix Labs
+// SPDX-License-Identifier: Apache-2.0
+
+package tenant
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	rbacv1 "k8s.io/api/rbac/v1"
+	"k8s.io/apimachinery/pkg/util/validation"
+	"k8s.io/client-go/tools/record"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
+
+	capsulev1beta1 "github.com/clastix/capsule/api/v1beta1"
+	capsulewebhook "github.com/clastix/capsule/pkg/webhook"
+	"github.com/clastix/capsule/pkg/webhook/utils"
+)
+
+type rbRegexHandler struct {
+}
+
+func RoleBindingRegexHandler() capsulewebhook.Handler {
+	return &rbRegexHandler{}
+}
+
+func (h *rbRegexHandler) validate(req admission.Request, decoder *admission.Decoder) *admission.Response {
+	tenant := &capsulev1beta1.Tenant{}
+	if err := decoder.Decode(req, tenant); err != nil {
+		return utils.ErroredResponse(err)
+	}
+
+	if len(tenant.Spec.AdditionalRoleBindings) > 0 {
+		for _, binding := range tenant.Spec.AdditionalRoleBindings {
+			for _, subject := range binding.Subjects {
+				if subject.Kind == rbacv1.ServiceAccountKind {
+					err := validation.IsDNS1123Subdomain(subject.Name)
+					if len(err) > 0 {
+						response := admission.Denied(fmt.Sprintf("Subject Name '%v' for binding '%v' is invalid. %v", subject.Name, binding.ClusterRoleName, strings.Join(err, ", ")))
+						return &response
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+func (h *rbRegexHandler) OnCreate(_ client.Client, decoder *admission.Decoder, _ record.EventRecorder) capsulewebhook.Func {
+	return func(_ context.Context, req admission.Request) *admission.Response {
+		return h.validate(req, decoder)
+	}
+}
+
+func (h *rbRegexHandler) OnDelete(client.Client, *admission.Decoder, record.EventRecorder) capsulewebhook.Func {
+	return func(context.Context, admission.Request) *admission.Response {
+		return nil
+	}
+}
+
+func (h *rbRegexHandler) OnUpdate(_ client.Client, decoder *admission.Decoder, _ record.EventRecorder) capsulewebhook.Func {
+	return func(_ context.Context, req admission.Request) *admission.Response {
+		return h.validate(req, decoder)
+	}
+}