Limit Entity Reference Owner

A simple module that adds a field setting to entity reference fields which, when enabled, validates that the field only references entities that are owned by the owner of the entity on which the field is attached. If the entity does not implement EntityOwnerInterface or the owner ID is null, it instead validates against the current user.

For instance, let's say an article node references media entities via field_media. If an article is owned/authored by uid 1, then field_media will throw a validation error if it references a media entity owned by uid 2.