Let's consider a project A, with authors and copyright holders A1, A2, A3 etc, licensed under GPL v2.

Project B builds on project A (let's say they just outright import the source code of A and link against it statically for simplicity), but the author of B, B1, offers B under a dubious, non-GPL license (let's call it the "commercial use allowed only on even days of the month" license).

Can I, as somebody not affiliated with either A1, A2 etc. or B1,

  • Just use B under the terms of the GPL v2 (in this example, e.g. use it commercially on odd days of the month as well, as long as I comply with the GPLv2) without talking to anybody? Specifically, clause 3.6 states that

Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions.

  • Take action against B1 and make them explicitly grant me (and I suppose everybody else) these rights without the involvement of any or all of the original authors A1, A2 etc.?

3 Answers 3


Can I, as somebody not affiliated with either A1, A2 etc. or B1, just use B under the terms of the GPL v2?

No. B may well be violating A's copyright by distributing the derivative work under a licence other than GPLv2, but that doesn't entitle you to presume a different licence. Yes, GPLv2 grants you a licence from An, but that doesn't include a licence from B1, who would still be in position to accuse you of copyright infringement if you used B otherwise than in accordance with the licence under which you received it.

Can I, as somebody not affiliated with either A1, A2 etc. or B1, take action against B1 and make them explicitly grant me (and I suppose everybody else) these rights?

The right to start such an action is a third-party beneficiary right, and they are jurisdictionally-dependent. You can read more about that in this LWN article (usual disclosure: I wrote the article, but I didn't give the talk on which it's based). In jurisdictions where third-party rights exist, you will also need to be able to apply for specific performance (that is, a court order requiring B1 to release the code to you under GPLv2, instead of merely compensating you monetarily for your lost rights). Those are also jurisdictionally-dependent, and are also covered in the linked article.

Personally, I think your best bet is to contact the authors of A, point out what's happening, and (as Miral points out below) ask them if they intended this. If they didn't, then perhaps ask if you can help them do something about it (eg, donating funding so they can get a legal professional to contact B and explain to them the error of their ways).

  • 14
    It's entirely possible (though perhaps unlikely) that A deliberately licensed their work to B under different terms (e.g. a commercial license), and those different terms allow B to subsequently offer their own work under different terms from the GPL. As such, this answer is correct: you could ask A if B is allowed to do that, but you should not assume by default that they are not, or that it's safe to use B's work against the licensing terms they offer.
    – Miral
    Commented Apr 17 at 4:42
  • 1
    That is a very good point, and I thank you for making it.
    – MadHatter
    Commented Apr 17 at 11:44

Very subtly different:

offers B under GPLv3, but adds a dubious, non-GPL condition

This would be the case if they keep the original GPLv3 declarations from project A.

In that case, GPLv3 itself provides for:

If the Program as you received it, or any part of it, contains a notice stating that it is governed by this License along with a term that is a further restriction, you may remove that term.

Note: I did not realize that this text only exists in GPLv3, not the GPLv2 specified in question. I'm leaving this answer here for any future readers who may be interested in GPL generically.

  • That language is particular to GPLv3, and the question is specifically about GPLv2.
    – MadHatter
    Commented Apr 17 at 11:42
  • @MadHatter Ah, good point. I missed that.
    – jpa
    Commented Apr 17 at 12:12

Simplified non-lawyer answer.

The author of B has no right to withhold A from you. They have no obligation to provide additional services or products for free.

In the simplified scenario (B links to A), B must either provide you with the source code for A or provide you a way to get that source code (possibly by saying "It's somewhere on github").

Where it gets more complicated is if they alter the code for A somehow. (Say, by changing a line or two.) They still have to offer you a way to get the GPL version of the code, but not their changes.

They're even allowed to charge for any services they provide. Say, virus checking. (The example in the license is physical media. But any service at all, including something you can easily do yourself, is allowed.)

  • 1
    Note that there's a big difference between using GPL software for a SaaS product vs providing the binaries. If B provides the binaries for the modified version of A, they also have to offer the modified source. See gnu.org: Does the GPL require that source code of modified versions be posted to the public?.
    – Brian
    Commented Apr 17 at 16:06
  • 1
    "if they alter the code for A somehow ... They still have to offer you a way to get the GPL version of the code, but not their changes" sorry, but that's not true, see eg GPLv2 ss2b and 3. Modified versions of GPLv2 works, if distributed, must be under GPLv2, and if distributed as binary-only must be accompanied by complete corresponding source (or this must be made available to recipients of the binaries for no more than the cost of transmission).
    – MadHatter
    Commented Apr 18 at 5:20

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