Merge pull request #63403 from deads2k/server-14-creationpower

Automatic merge from submit-queue (batch tested with PRs 63258, 63398, 63403). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

don't block creation on lack of delete powers

Create and delete aren't the same thing, but the alternatives seem worse. This stops checking for deletion powers on create.  You still have to know the UID to create an effective ownerref, so name hunting is unrealistic.

@kubernetes/sig-api-machinery-pr-reviews 

```release-note
owner references can be set during creation without deletion power
```

plugin/pkg/admission/gc/gc_admission.go

@@ -95,21 +95,26 @@ func (a *gcPermissionsEnforcement) Validate(attributes admission.Attributes) (er
 		return nil
 	}
 
-	deleteAttributes := authorizer.AttributesRecord{
+	// if you are creating a thing, you should always be allowed to set an owner ref since you logically had the power
-		User:            attributes.GetUserInfo(),
+	// to never create it.  We still need to check block owner deletion below, because the power to delete does not
-		Verb:            "delete",
+	// imply the power to prevent deletion on other resources.
-		Namespace:       attributes.GetNamespace(),
+	if attributes.GetOperation() != admission.Create {
-		APIGroup:        attributes.GetResource().Group,
+		deleteAttributes := authorizer.AttributesRecord{
-		APIVersion:      attributes.GetResource().Version,
+			User:            attributes.GetUserInfo(),
-		Resource:        attributes.GetResource().Resource,
+			Verb:            "delete",
-		Subresource:     attributes.GetSubresource(),
+			Namespace:       attributes.GetNamespace(),
-		Name:            attributes.GetName(),
+			APIGroup:        attributes.GetResource().Group,
-		ResourceRequest: true,
+			APIVersion:      attributes.GetResource().Version,
-		Path:            "",
+			Resource:        attributes.GetResource().Resource,
-	}
+			Subresource:     attributes.GetSubresource(),
-	decision, reason, err := a.authorizer.Authorize(deleteAttributes)
+			Name:            attributes.GetName(),
-	if decision != authorizer.DecisionAllow {
+			ResourceRequest: true,
-		return admission.NewForbidden(attributes, fmt.Errorf("cannot set an ownerRef on a resource you can't delete: %v, %v", reason, err))
+			Path:            "",
+		}
+		decision, reason, err := a.authorizer.Authorize(deleteAttributes)
+		if decision != authorizer.DecisionAllow {
+			return admission.NewForbidden(attributes, fmt.Errorf("cannot set an ownerRef on a resource you can't delete: %v, %v", reason, err))
+		}
 	}
 
 	// Further check if the user is setting ownerReference.blockOwnerDeletion to
@@ -119,7 +124,7 @@ func (a *gcPermissionsEnforcement) Validate(attributes admission.Attributes) (er
 	for _, ref := range newBlockingRefs {
 		records, err := a.ownerRefToDeleteAttributeRecords(ref, attributes)
 		if err != nil {
-			return admission.NewForbidden(attributes, fmt.Errorf("cannot set blockOwnerDeletion in this case because cannot find RESTMapping for APIVersion %s Kind %s: %v, %v", ref.APIVersion, ref.Kind, reason, err))
+			return admission.NewForbidden(attributes, fmt.Errorf("cannot set blockOwnerDeletion in this case because cannot find RESTMapping for APIVersion %s Kind %s: %v", ref.APIVersion, ref.Kind, err))
 		}
 		// Multiple records are returned if ref.Kind could map to multiple
 		// resources. User needs to have delete permission on all the

plugin/pkg/admission/gc/gc_admission_test.go

@@ -102,6 +102,9 @@ func TestGCAdmission(t *testing.T) {
 		return err == nil
 	}
 	expectCantSetOwnerRefError := func(err error) bool {
+		if err == nil {
+			return false
+		}
 		return strings.Contains(err.Error(), "cannot set an ownerRef on a resource you can't delete")
 	}
 	tests := []struct {
@@ -140,7 +143,7 @@ func TestGCAdmission(t *testing.T) {
 			username:   "non-deleter",
 			resource:   api.SchemeGroupVersion.WithResource("pods"),
 			newObj:     &api.Pod{ObjectMeta: metav1.ObjectMeta{OwnerReferences: []metav1.OwnerReference{{Name: "first"}}}},
-			checkError: expectCantSetOwnerRefError,
+			checkError: expectNoError,
 		},
 		{
 			name:       "non-pod-deleter, create, no objectref change",
@@ -154,7 +157,7 @@ func TestGCAdmission(t *testing.T) {
 			username:   "non-pod-deleter",
 			resource:   api.SchemeGroupVersion.WithResource("pods"),
 			newObj:     &api.Pod{ObjectMeta: metav1.ObjectMeta{OwnerReferences: []metav1.OwnerReference{{Name: "first"}}}},
-			checkError: expectCantSetOwnerRefError,
+			checkError: expectNoError,
 		},
 		{
 			name:       "non-pod-deleter, create, objectref change, but not a pod",
@@ -254,23 +257,26 @@ func TestGCAdmission(t *testing.T) {
 			checkError: expectNoError,
 		},
 	}
-	gcAdmit, err := newGCPermissionsEnforcement()
-	if err != nil {
-		t.Error(err)
-	}
 
 	for _, tc := range tests {
-		operation := admission.Create
+		t.Run(tc.name, func(t *testing.T) {
-		if tc.oldObj != nil {
+			gcAdmit, err := newGCPermissionsEnforcement()
-			operation = admission.Update
+			if err != nil {
-		}
+				t.Error(err)
-		user := &user.DefaultInfo{Name: tc.username}
+			}
-		attributes := admission.NewAttributesRecord(tc.newObj, tc.oldObj, schema.GroupVersionKind{}, metav1.NamespaceDefault, "foo", tc.resource, tc.subresource, operation, user)
 
-		err := gcAdmit.Validate(attributes)
+			operation := admission.Create
-		if !tc.checkError(err) {
+			if tc.oldObj != nil {
-			t.Errorf("%v: unexpected err: %v", tc.name, err)
+				operation = admission.Update
-		}
+			}
+			user := &user.DefaultInfo{Name: tc.username}
+			attributes := admission.NewAttributesRecord(tc.newObj, tc.oldObj, schema.GroupVersionKind{}, metav1.NamespaceDefault, "foo", tc.resource, tc.subresource, operation, user)
+
+			err = gcAdmit.Validate(attributes)
+			if !tc.checkError(err) {
+				t.Errorf("unexpected err: %v", err)
+			}
+		})
 	}
 }