Scope barman Secret RBAC

Avoid granting namespace-wide Secret access when ObjectStores do not need credential Secrets.

Ref: #892
Signed-off-by: Martin Hansen <dontbeevilpls@gmail.com>

internal/cnpgi/operator/specs/role.go

@@ -60,7 +60,7 @@ func BuildRoleRules(barmanObjects []barmancloudv1.ObjectStore) []rbacv1.PolicyRu
 		}
 	}
 
-	return []rbacv1.PolicyRule{
+	rules := []rbacv1.PolicyRule{
 		{
 			APIGroups: []string{
 				barmancloudv1.GroupVersion.Group,
@@ -87,7 +87,11 @@ func BuildRoleRules(barmanObjects []barmancloudv1.ObjectStore) []rbacv1.PolicyRu
 			},
 			ResourceNames: barmanObjectsSet.ToSortedList(),
 		},
-		{
+	}
+
+	secrets := secretsSet.ToSortedList()
+	if len(secrets) > 0 {
+		rules = append(rules, rbacv1.PolicyRule{
 			APIGroups: []string{
 				"",
 			},
@@ -99,9 +103,11 @@ func BuildRoleRules(barmanObjects []barmancloudv1.ObjectStore) []rbacv1.PolicyRu
 				"watch",
 				"list",
 			},
-			ResourceNames: secretsSet.ToSortedList(),
-		},
+			ResourceNames: secrets,
+		})
 	}
+
+	return rules
 }
 
 // ObjectStoreNamesFromRole extracts the ObjectStore names referenced

internal/cnpgi/operator/specs/role_test.go

@@ -78,13 +78,12 @@ var _ = Describe("BuildRoleRules", func() {
 		Expect(rules[2].ResourceNames).To(ConsistOf("secret-a", "secret-b"))
 	})
 
-	It("should produce rules with empty ResourceNames for empty input", func() {
+	It("should not produce a secrets rule for empty input", func() {
 		rules := BuildRoleRules(nil)
-		Expect(rules).To(HaveLen(3))
+		Expect(rules).To(HaveLen(2))
 		Expect(rules[0].ResourceNames).To(BeEmpty())
 		Expect(rules[0].ResourceNames).NotTo(BeNil())
 		Expect(rules[1].ResourceNames).To(BeEmpty())
-		Expect(rules[2].ResourceNames).To(BeEmpty())
 	})
 
 	It("should deduplicate secret names across ObjectStores", func() {
@@ -95,6 +94,31 @@ var _ = Describe("BuildRoleRules", func() {
 		rules := BuildRoleRules(objects)
 		Expect(rules[2].ResourceNames).To(Equal([]string{"shared-secret"}))
 	})
+
+	It("should not produce a secrets rule when ObjectStores use IAM role inheritance", func() {
+		objects := []barmancloudv1.ObjectStore{
+			{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "store-a",
+					Namespace: "default",
+				},
+				Spec: barmancloudv1.ObjectStoreSpec{
+					Configuration: barmanapi.BarmanObjectStoreConfiguration{
+						DestinationPath: "s3://bucket/path",
+						BarmanCredentials: barmanapi.BarmanCredentials{
+							AWS: &barmanapi.S3Credentials{
+								InheritFromIAMRole: true,
+							},
+						},
+					},
+				},
+			},
+		}
+		rules := BuildRoleRules(objects)
+		Expect(rules).To(HaveLen(2))
+		Expect(rules[0].ResourceNames).To(Equal([]string{"store-a"}))
+		Expect(rules[1].ResourceNames).To(Equal([]string{"store-a"}))
+	})
 })
 
 var _ = Describe("BuildRole", func() {

internal/cnpgi/operator/specs/secrets.go

@@ -28,6 +28,9 @@ import (
 func CollectSecretNamesFromCredentials(barmanCredentials *barmanapi.BarmanCredentials) []string {
 	var references []*machineryapi.SecretKeySelector
 	if barmanCredentials.AWS != nil {
+		// When using IAM role inheritance, barman-cloud uses the pod
+		// environment credential chain and does not read credential Secrets.
+		if !barmanCredentials.AWS.InheritFromIAMRole {
 			references = append(
 				references,
 				barmanCredentials.AWS.AccessKeyIDReference,
@@ -36,6 +39,7 @@ func CollectSecretNamesFromCredentials(barmanCredentials *barmanapi.BarmanCreden
 				barmanCredentials.AWS.SessionToken,
 			)
 		}
+	}
 	if barmanCredentials.Azure != nil {
 		// When using default Azure credentials or managed identity, no secrets are required
 		if !barmanCredentials.Azure.UseDefaultAzureCredentials &&

internal/cnpgi/operator/specs/secrets_test.go

@@ -57,6 +57,29 @@ var _ = Describe("CollectSecretNamesFromCredentials", func() {
 			secrets := CollectSecretNamesFromCredentials(credentials)
 			Expect(secrets).To(BeEmpty())
 		})
+
+		It("should return empty list when using InheritFromIAMRole", func() {
+			credentials := &barmanapi.BarmanCredentials{
+				AWS: &barmanapi.S3Credentials{
+					InheritFromIAMRole: true,
+					AccessKeyIDReference: &machineryapi.SecretKeySelector{
+						LocalObjectReference: machineryapi.LocalObjectReference{
+							Name: "aws-secret",
+						},
+						Key: "access-key-id",
+					},
+					RegionReference: &machineryapi.SecretKeySelector{
+						LocalObjectReference: machineryapi.LocalObjectReference{
+							Name: "aws-region",
+						},
+						Key: "region",
+					},
+				},
+			}
+
+			secrets := CollectSecretNamesFromCredentials(credentials)
+			Expect(secrets).To(BeEmpty())
+		})
 	})
 
 	Context("when collecting secrets from Azure credentials", func() {

internal/controller/objectstore_controller_test.go

@@ -31,8 +31,8 @@ import (
 	apierrs "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
-	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/types"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/fake"
 	"sigs.k8s.io/controller-runtime/pkg/client/interceptor"
@@ -261,7 +261,7 @@ var _ = Describe("ObjectStoreReconciler", func() {
 			Expect(result).To(Equal(reconcile.Result{}))
 		})
 
-		It("should produce empty ResourceNames when all ObjectStores are deleted", func() {
+		It("should omit the secrets rule when all ObjectStores are deleted", func() {
 			store := newTestObjectStore("my-store", "default", "aws-creds")
 			role := newLabeledRole("my-cluster", "default", []barmancloudv1.ObjectStore{*store})
 
@@ -291,10 +291,11 @@ var _ = Describe("ObjectStoreReconciler", func() {
 				Name:      "my-cluster-barman-cloud",
 			}, &updatedRole)).To(Succeed())
 
-			// All rules should have empty ResourceNames
 			Expect(updatedRole.Rules[0].ResourceNames).To(BeEmpty())
 			Expect(updatedRole.Rules[1].ResourceNames).To(BeEmpty())
-			Expect(updatedRole.Rules[2].ResourceNames).To(BeEmpty())
+			for _, rule := range updatedRole.Rules {
+				Expect(rule.Resources).NotTo(Equal([]string{"secrets"}))
+			}
 		})
 
 		It("should return an error when listing Roles fails", func() {