Patent clauses in software licenses

Template:Duds Some software licences contain clauses which place requirements on patent holders who participate in distributing that software. These can be useful, but only in some narrow cases.

Limits to effectiveness

1. These clauses only apply to patent holders who distribute the software which uses this licence.
2. The stronger the clause, the less likely it is that dangerous patent holders will distribute software that uses the licence.

GNU GPL v2

See section 6 and section 7.

Dan Ravicher argues that GPLv2 includes an implicit patent grant.

GNU GPL v3

• http://www.gnu.org/licenses/gpl.html

Section 10:

you may not impose a license fee, royalty, or other charge for exercise of rights granted under this License, and you may not initiate litigation (including a cross-claim or counterclaim in a lawsuit) alleging that any patent claim is infringed by making, using, selling, offering for sale, or importing the Program or any portion of it.

Also, section 12, which is very similar to GPLv2's section 7.

Related discussions

• From the 25th minute onward, Bradely Kuhn explains GPLv3 section 11
• http://fsfe.org/projects/gplv3/brussels-rms-transcript.en.html#retaliation

LGPL 2.1

• Discussion about Google's Chrome using LGPL'd library and having a patent licence, Chris DiBona gives Google's position

Apache License

• http://www.apache.org/licenses/LICENSE-2.0

Section 3:

If You institute patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that the Work or a Contribution incorporated within the Work constitutes direct or contributory patent infringement, then any patent licenses granted to You under this License for that Work shall terminate as of the date such litigation is filed.

Mozilla Public License

• http://www.mozilla.org/MPL/MPL-1.1.html

Section 8:

(excerpt) "...if You initiate litigation by asserting a patent infringement claim (excluding declatory judgment actions) against Initial Developer or a Contributor (the Initial Developer or Contributor against whom You file such action is referred to as "Participant") alleging that..."

WebM licence

This is the licence used by Google for the V8 video codec, first published in May 2010:

• http://www.webmproject.org/license/software/

Subject to the terms and conditions of the above License, Google hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer this implementation of VP8, where such license applies only to those patent claims, both currently owned by Google and acquired in the future, licensable by Google that are necessarily infringed by this implementation of VP8. If You or your agent or exclusive licensee institute or order or agree to the institution of patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that this implementation of VP8 or any code incorporated within this implementation of VP8 constitutes direct or contributory patent infringement, or inducement of patent infringement, then any rights granted to You under this License for this implementation of VP8 shall terminate as of the date such litigation is filed.

Related pages on ESP Wiki

• Duds and non-solutions
• Free software - practically all discussion of such clauses is in relation to free software licences
• Patent promises

External links

• Packaging Open Source, a paper which looks briefly at the patent clauses of various free software licences, by Mark Webbink, December 2009
• A forum comment describing a possible limit to the effectiveness of licences