Allow disabling cross-namespace references

controllers/helmrelease_controller.go

@@ -48,7 +48,9 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/reconcile"
 	"sigs.k8s.io/controller-runtime/pkg/source"
 
+	apiacl "github.com/fluxcd/pkg/apis/acl"
 	"github.com/fluxcd/pkg/apis/meta"
+	"github.com/fluxcd/pkg/runtime/acl"
 	"github.com/fluxcd/pkg/runtime/events"
 	"github.com/fluxcd/pkg/runtime/metrics"
 	"github.com/fluxcd/pkg/runtime/predicates"
@@ -78,6 +80,7 @@ type HelmReleaseReconciler struct {
 	EventRecorder         kuberecorder.EventRecorder
 	ExternalEventRecorder *events.Recorder
 	MetricsRecorder       *metrics.Recorder
+	NoCrossNamespaceRef   bool
 }
 
 func (r *HelmReleaseReconciler) SetupWithManager(mgr ctrl.Manager, opts HelmReleaseReconcilerOptions) error {
@@ -213,6 +216,13 @@ func (r *HelmReleaseReconciler) reconcile(ctx context.Context, hr v2.HelmRelease
 	// Reconcile chart based on the HelmChartTemplate
 	hc, reconcileErr := r.reconcileChart(ctx, &hr)
 	if reconcileErr != nil {
+		if acl.IsAccessDenied(reconcileErr) {
+			log.Error(reconcileErr, "access denied to cross-namespace source")
+			r.event(ctx, hr, hr.Status.LastAttemptedRevision, events.EventSeverityError, reconcileErr.Error())
+			return v2.HelmReleaseNotReady(hr, apiacl.AccessDeniedReason, reconcileErr.Error()),
+				ctrl.Result{RequeueAfter: hr.Spec.Interval.Duration}, nil
+		}
+
 		msg := fmt.Sprintf("chart reconciliation failed: %s", reconcileErr.Error())
 		r.event(ctx, hr, hr.Status.LastAttemptedRevision, events.EventSeverityError, msg)
 		return v2.HelmReleaseNotReady(hr, v2.ArtifactFailedReason, msg), ctrl.Result{Requeue: true}, reconcileErr

controllers/helmrelease_controller_chart.go

@@ -28,6 +28,7 @@ import (
 	"reflect"
 	"strings"
 
+	"github.com/fluxcd/pkg/runtime/acl"
 	"github.com/hashicorp/go-retryablehttp"
 	"helm.sh/helm/v3/pkg/chart"
 	"helm.sh/helm/v3/pkg/chart/loader"
@@ -47,6 +48,14 @@ func (r *HelmReleaseReconciler) reconcileChart(ctx context.Context, hr *v2.HelmR
 		Name:      hr.GetHelmChartName(),
 	}
 
+	if r.NoCrossNamespaceRef && chartName.Namespace != hr.Namespace {
+		return nil, acl.AccessDeniedError(fmt.Sprintf("can't access '%s/%s', cross-namespace references have been blocked",
+			hr.Spec.Chart.Spec.SourceRef.Kind, types.NamespacedName{
+				Namespace: hr.Spec.Chart.Spec.SourceRef.Namespace,
+				Name:      hr.Spec.Chart.Spec.SourceRef.Name,
+			}))
+	}
+
 	// Garbage collect the previous HelmChart if the namespace named changed.
 	if hr.Status.HelmChart != "" && hr.Status.HelmChart != chartName.String() {
 		if err := r.deleteHelmChart(ctx, hr); err != nil {

controllers/helmrelease_controller_chart_test.go

@@ -41,6 +41,7 @@ func TestHelmReleaseReconciler_reconcileChart(t *testing.T) {
 		expectHelmChartStatus string
 		expectGC              bool
 		expectErr             bool
+		noCrossNamspaceRef    bool
 	}{
 		{
 			name: "new HelmChart",
@@ -140,6 +141,33 @@ func TestHelmReleaseReconciler_reconcileChart(t *testing.T) {
 			expectHelmChartStatus: "cross/default-test-release",
 			expectGC:              true,
 		},
+		{
+			name: "block cross namespace access when flag is set",
+			hr: &v2.HelmRelease{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "test-release",
+					Namespace: "default",
+				},
+				Spec: v2.HelmReleaseSpec{
+					Interval: metav1.Duration{Duration: time.Minute},
+					Chart: v2.HelmChartTemplate{
+						Spec: v2.HelmChartTemplateSpec{
+							Chart: "chart",
+							SourceRef: v2.CrossNamespaceObjectReference{
+								Name:      "test-repository",
+								Kind:      "HelmRepository",
+								Namespace: "cross",
+							},
+						},
+					},
+				},
+				Status: v2.HelmReleaseStatus{
+					HelmChart: "",
+				},
+			},
+			noCrossNamspaceRef: true,
+			expectErr:          true,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -156,7 +184,8 @@ func TestHelmReleaseReconciler_reconcileChart(t *testing.T) {
 			}
 
 			r := &HelmReleaseReconciler{
-				Client: c,
+				Client:              c,
+				NoCrossNamespaceRef: tt.noCrossNamspaceRef,
 			}
 
 			hc, err := r.reconcileChart(logr.NewContext(context.TODO(), logr.Discard()), tt.hr)

docs/spec/v2beta1/helmreleases.md

@@ -687,6 +687,10 @@ Supported source types:
 The `HelmChart` is created in the same namespace as the `sourceRef`,
 with a name matching the `HelmRelease` `<metadata.namespace>-<metadata.name>`.
 
+> **Note** that on multi-tenant clusters,  platform admins can disable cross-namespace references
+> with the `--no-cross-namespace-refs=true` flag. When this flag is set, the helmrelease can only
+> refer to sources in the same  namespace as the helmrelease object.
+
 The `chart.spec.chart` can either contain:
 
 - The name of the chart as made available by the `HelmRepository`

go.mod

@@ -6,9 +6,10 @@ replace github.com/fluxcd/helm-controller/api => ./api
 
 require (
 	github.com/fluxcd/helm-controller/api v0.15.0
+	github.com/fluxcd/pkg/apis/acl v0.0.3
 	github.com/fluxcd/pkg/apis/kustomize v0.3.1
 	github.com/fluxcd/pkg/apis/meta v0.10.2
-	github.com/fluxcd/pkg/runtime v0.12.3
+	github.com/fluxcd/pkg/runtime v0.12.4
 	github.com/fluxcd/source-controller/api v0.20.1
 	github.com/go-logr/logr v1.2.2
 	github.com/hashicorp/go-retryablehttp v0.6.8

go.sum

@@ -320,6 +320,8 @@ github.com/fluxcd/pkg/apis/meta v0.10.2 h1:pnDBBEvfs4HaKiVAYgz+e/AQ8dLvcgmVfSeBr
 github.com/fluxcd/pkg/apis/meta v0.10.2/go.mod h1:KQ2er9xa6koy7uoPMZjIjNudB5p4tXs+w0GO6fRcy7I=
 github.com/fluxcd/pkg/runtime v0.12.3 h1:h21AZ3YG5MAP7DxFF9hfKrP+vFzys2L7CkUbPFjbP/0=
 github.com/fluxcd/pkg/runtime v0.12.3/go.mod h1:imJ2xYy/d4PbSinX2IefmZk+iS2c1P5fY0js8mCE4SM=
+github.com/fluxcd/pkg/runtime v0.12.4 h1:gA27RG/+adN2/7Qe03PB46Iwmye/MusPCpuS4zQ2fW0=
+github.com/fluxcd/pkg/runtime v0.12.4/go.mod h1:gspNvhAqodZgSmK1ZhMtvARBf/NGAlxmaZaIOHkJYsc=
 github.com/fluxcd/source-controller/api v0.20.1 h1:BfYw1gNHykiCVFNtDz3atcf3Vph+arfuveKmouI98wE=
 github.com/fluxcd/source-controller/api v0.20.1/go.mod h1:Ab2qDmAUz6ZCp8UaHYLYzxyFrC1FQqEqjxiROb/Rdiw=
 github.com/form3tech-oss/jwt-go v3.2.2+incompatible/go.mod h1:pbq4aXjuKjdthFRnoDwaVPLA+WlJuPGy+QneDUgJi2k=

main.go

@@ -30,6 +30,7 @@ import (
 	ctrl "sigs.k8s.io/controller-runtime"
 	crtlmetrics "sigs.k8s.io/controller-runtime/pkg/metrics"
 
+	"github.com/fluxcd/pkg/runtime/acl"
 	"github.com/fluxcd/pkg/runtime/client"
 	"github.com/fluxcd/pkg/runtime/events"
 	"github.com/fluxcd/pkg/runtime/leaderelection"
@@ -70,6 +71,7 @@ func main() {
 		httpRetry             int
 		clientOptions         client.Options
 		logOptions            logger.Options
+		aclOptions            acl.Options
 		leaderElectionOptions leaderelection.Options
 	)
 
@@ -83,6 +85,7 @@ func main() {
 	flag.IntVar(&httpRetry, "http-retry", 9, "The maximum number of retries when failing to fetch artifacts over HTTP.")
 	clientOptions.BindFlags(flag.CommandLine)
 	logOptions.BindFlags(flag.CommandLine)
+	aclOptions.BindFlags(flag.CommandLine)
 	leaderElectionOptions.BindFlags(flag.CommandLine)
 	flag.Parse()
 
@@ -139,6 +142,7 @@ func main() {
 		EventRecorder:         mgr.GetEventRecorderFor(controllerName),
 		ExternalEventRecorder: eventRecorder,
 		MetricsRecorder:       metricsRecorder,
+		NoCrossNamespaceRef:   aclOptions.NoCrossNamespaceRefs,
 	}).SetupWithManager(mgr, controllers.HelmReleaseReconcilerOptions{
 		MaxConcurrentReconciles:   concurrent,
 		DependencyRequeueInterval: requeueDependency,