Is copying an infringing derivative an infringement against the original work's author when copying the original would generally be legal?

Question

Suppose someone creates an unauthorized music video to accompany a popular song, thus making an infringing derivative (assuming fair dealing or other exceptions don't apply in this case). This derivative author then gives you permission to copy their derivative. Independently, you have a legal right to copy the original song (an example would be you live in Canada where personal-use copying of music is generally legal).

It then appears that you aren't infringing the derivative author's rights since you have their permission, nor are you infringing the original author's rights since there's an exemption within the law.

It seems weird to me that there might be a legal possibility for you to own an unauthorized derivative by performing what appears to be a completely legal copy action, so I'm wondering if I missed something here.

Is the copying of the derivative work legal? Does the answer change depending on whether you have knowledge that the derivative is infringing? I'm most interested in answers covering Canada or the European Union.

Edit: I've since stumbled on a journal article by William J. Braithwaite that basically discusses my question in pgs 213-220, minus the portion about copying the original being legal. However, it discusses Canadian copyright law as it was in 1982 and is rather inconclusive.

Answer 1

Whoever "derived" the illegal derivative work most likely has copyright in his derivations, unless they are not worth copyright protections. Say I take the Harry Potter books and add a few chapters and try to sell it - that's copyright infringement of course, but I have the copyright on these additional chapters.

However, I don't have the right to allow you to copy the derived work. And even if you have the right to copy the original work, you don't have the right to copy the derived work because it is a different work. I could extract my changes, and allow you to take them and do with them what you like. You could then create an illegally derived work yourself. I couldn't sue you, but the original copyright holder could.

To the comments: One, a work and a derivative of the work are not the same, so even if you have the right to make a copy of a work, that doesn’t give you any right whatsoever to copy a derivative work - they are not the same work. Two, the copyright holder has the exclusive right to control copying and the creation of derivative works. If the copyright holder doesn’t want derivatives to exist, then creating them, copying them etc. is always copyright infringement.