What are the most difficult questions in open source licensing?

These are the things my clients and I think about a lot.

What is the scope of derviative works under the GPLv2?

I have often called this the $64,000 question of open source licensing. (Some of you are too young for that reference, but it comes from a game show in the 1960’s — back then, that much bought you a house, not just a Mercedes Benz E Class.) There are some relatively easy cases to determine GPL scope, and you will find more about those on the FSF’s FAQ about GPLv2 on my links page. But there are other cases, such as those involving Linux kernel drivers, dual processors, virtualization layers, that are more complicated. To analyze these questions, one needs some technical understanding about how software is put together, and also an understanding of the legal principles underlying GPL.

What constitutes distribution under GPL and other copyleft licenses?

It’s pretty well understood that the copyleft requirements of most licenses only adhere when one actually distirbutes copies of code. (That isn’t true for all the copyleft licenses, just the most common ones.) But distribution can become a complicated question, particularly when copies are provided to developers, testers, corporate affiliates, and outsource providers. This is a situation where the right legal help can be of great benefit in managing the need to comply with copyleft.

Are there implied patent licenses under GPL and other open source licenses?

Although some open source licenses have express patent licenses, none of the have reservations of rights. So, there may be “implied licenses” granted when one contributes to or distributes open source code. This causes great concern for companies that have patent portfolios to protect. The hard part is not usually patents that would read directly on the code — it’s of greater concern how far beyond that an implied license would go. The law on implied licenses is very unclear, and overlaps with notions of patent exhaustion and estoppel.

How do I comply with notice requirements for embedded software?

Notice requirements in open source licenses aren’t usually complicated, but they can be an enormous headache. The more complex the product, and the less it looks like application software, the more difficult it is to apply notices consistently and rationally and still be compliant. Companies use a lot of different practices, most of which are a compromise of some sort. Coming up with a notice procedure takes knowledge of open source requirements, but also common sense and a practical approach.

Does open source licensing allow or require me to use trademarks?

Open source licenses are not trademark licenses. But there is a tension between trademark law and open source licensing. Trademark law cover when you can, or must, use the trademark, logo or brand name of a company that is a source for software. It also covers when you must not. Most companies that release open source software should carefully consider what brands or identifiers they will apply to that software, and enunciating transparent policies for trademark use.