Yes. You heard it. There is not an actual law that is actually broken when you are committing an act of cannibalism. However, there are still conditions in which it can definitely be considered illegal.
Let us start by asserting that in order to eat someone you should probably commit murder before doing it so. But this is not always the case. For example if the person being cannibalized just chops of a part of his flesh and does not die, no crime has been committed. Also eating the flesh of a dead person is also not considered a crime. This completely justifies the consumption of corpses in cases such as getting trapped in an avalanche where partners die. However, there should be proof that these people were not in fact killed.