I made my own open source license. Is it any good? Is it legal?

1. Rolling your own anything-which-requires-skill usually results in a product inferior to what a professional would produce so it's best not to do so unless you have a reason which makes it a better course of action. This isn't to say rolling your own is a bad idea. In fact it benefits the opensource community by introducing new ideas, and showing areas for new license demand. But it's important to make sure you understand the consequences of making/using a bad license.

2. Custom licenses aren't likely to be widely used, because anyone who wants to use works under this license may run into license compatibility issues when combining works. Also many people will steer clear simply because an untested license is a wildcard. People like to know how a license will hold up in court. So by using a custom license you'll be limiting the potential audience for your work.

3. Your license will be awkward to actually use. You've taken text from existing licenses, and those licenses need to be adhered to when distributing your license, or you violate the copyright of the authors of those original licenses. The key example of this being that both the 3 Clause BSD license, and the Apache 2.0 License require a copy of the license to be distributed with works. So when you use your license you must also include the BSD and Apache licenses. In doing so, you'll need to be careful not to accidentally try to license those license texts under your license, or each other. You'll also need to be careful not to accidentally license you work under the BSD, or Apache licenses (unless you're wanting to do that). You might be able to get around all of this by arguing fair use of the text in your license, but that's not a guarantee.

   It's also worth noting that by posting the license on this site you've licensed it under the CC BY-SA 4.0 which means anyone who takes it from here will also need to adhere to the CC BY-SA 4.0 when using your license.

If you're having trouble finding a license that meets your needs try browsing the list on OSI, or consider hiring a lawyer to draft one for you (or proof this one for you).

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Copyright James Daniel Marrs Ritchey. This material was created for submission at 'https://opensource.stackexchange.com/questions/10092/i-made-my-own-open-source-license-is-it-any-good-is-it-legal', but can also be alternatively obtained from 'https://snippetly.blogspot.com/2020/07/making-homebrew-license.html' under the terms of any of the following licenses: Ritchey Permissive License v8 (https://jamesdanielmarrsritchey.blogspot.com/2020/01/ritchey-permissive-license-v8.html), The MIT License (https://opensource.org/licenses/MIT), Ritchey 2020 Permissive License v1 (https://jamesdanielmarrsritchey.blogspot.com/2020/05/ritchey-2020-permissive-license-v1.html).

One problem with your proposed license is as follows.

BSD license says:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

This means the list of conditions and the disclaimer must be retained.

Your license says:

Redistributions of source code must retain the above copyright notice, all copyright, patent, trademark, and attribution notices, excluding those notices that do not pertain to any part of the Derivative Works, this list of conditions and the following disclaimer.

I bolded the part that I can interpret as being a single clause. Now your license says that the list of conditions and the disclaimer are not required to be retained.

Regarding the patent allowances and, more importantly, requirements:

If I was evaluating your license and I saw those conditions, I would immediately wonder whether those requirements are 1) reasonable and 2) in my best interest. Since you said

My legal knowledge is nil.

... chances are there are some loopholes in your wording that would come to bite me in the rear in some way down the road, even IF I assume you were in fact simply ignorant in the first place and not secretly malicious. The well-known licenses are drafted over months and sometimes years by professionals who address issues like this. Once I realize your license was homegrown I'd try to forget everything about your software as fast as I could.

If I wanted to incorporate your software into my own program which I wanted to keep proprietary, I would not do it based on the patent concerns I just laid out. If I wanted to incorporate your software into my library or program which I wanted to release as free software, I wouldn't use your software either because then I'd be responsible for figuring out license compatibility between your homegrown license and other licenses.

TL;DR use a known license, pick the one you like the most.