GLEP 76: Copyright Policy

Purpose / Scope

This policy documents how Gentoo contributors comply and document copyright for any contributions made to Gentoo. Anyone committing documentation or sources to any repository hosted on Gentoo infrastructure or to any official Gentoo project (independently of hosting) must comply with this policy. Unofficial Gentoo projects are also recommended to use this policy.

Questions regarding this policy should be directed to the Council or the gentoo-project mailing list. Any concerns over possible copyright violations should be directed to the Council if they cannot be worked out with the appropriate maintainer.

Licensing of Gentoo Projects

Every Gentoo project must abide by the Gentoo Social Contract [2] and release its work under one or more of the following:

1. The GNU General Public License, version 2 or later (GPL-2+) [3].
2. The Creative Commons Attribution-ShareAlike 4.0 License (CC-BY-SA-4.0, only for documentation) [4]. Existing projects may also stay with CC-BY-SA-3.0 [5].
3. A license approved as GPL compatible by the Free Software Foundation [6].

Exceptions for other free software licenses will be granted by the Gentoo Council on a case by case basis.

Certificate of Origin

All commits to Gentoo project repositories shall be accompanied by a certificate of origin. The purpose of the certificate is to declare that the contribution can be modified and redistributed in accordance with the project's license.

For commits made using a VCS, the committer shall certify agreement to the Certificate of Origin by adding

Signed-off-by: Name <e-mail>

to the commit message as a separate line, using a known identity as a natural person. This could be the committer's real name or an established online identity.

The following is the current Gentoo Certificate of Origin, revision 1:

By making a contribution to this project, I certify that:

1. The contribution was created in whole or in part by me, and I have the right to submit it under the free software license indicated in the file; or
2. The contribution is based upon previous work that, to the best of my knowledge, is covered under an appropriate free software license, and I have the right under that license to submit that work with modifications, whether created in whole or in part by me, under the same free software license (unless I am permitted to submit under a different license), as indicated in the file; or
3. The contribution is a license text (or a file of similar nature), and verbatim distribution is allowed; or
4. The contribution was provided directly to me by some other person who certified 1., 2., 3., or 4., and I have not modified it.

I understand and agree that this project and the contribution are public and that a record of the contribution (including all personal information I submit with it, including my sign-off) is maintained indefinitely and may be redistributed consistent with this project or the free software license(s) involved.

The Gentoo Certificate of Origin is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License [4]. It is based on the Linux Kernel DCO [7], released by Open Source Development Labs, Inc. in 2005 under a CC-BY-SA-2.5 License.

Alternatively, and if it is applicable, committers can certify their commits with the Linux Kernel DCO 1.1 [8]. This shall be indicated by adding (DCO-1.1) at the end of the Signed-off-by line. Using the Gentoo Certificate of Origin is strongly preferred.

Copyright Attribution

All copyrightable files included in Gentoo projects must contain appropriate copyright and license notices, as defined by this policy. For files in textual format, these notices normally appear near the top of the file. When technical limitations do not allow for text notices in the file itself (e.g., for binary image file formats), copyright and license can be stated in an accompanying text file in the same directory.

A proper copyright notice reads:

Copyright YEARS MAIN-CONTRIBUTOR [OTHER-CONTRIBUTOR]... [and others]

It must list the main copyright holder, who is usually the original author, or the contributor holding copyright to the largest portion of the file. Additional copyright holders can be listed, but this is normally not required. The "and others" text may be omitted if the explicitly listed contributors hold copyright to the entire file. In some jurisdictions, the copyright holder can also be a company or other legal entity, and therefore be different from the original author.

Any requirement (e.g., by law, or by the file's license) to keep existing copyright notices intact is not affected by this policy.

Anyone finding a file out of compliance should file a bug against the associated project/package providing as much information as possible. Files that are not brought into compliance within 60 days or upon a request for removal by a aggrieved copyright holder will be removed. Any concerns not addressed by a maintainer can be appealed to the Council.

Simplified Attribution

Alternatively, projects are welcome to use a simplified form of the copyright notice, which reads:

Copyright YEARS Gentoo Authors

Projects using this scheme must track authorship in a VCS, unless they list all authors of copyrightable contributions in an AUTHORS file.

Policy

This document aims to provide a single consistent copyright policy for all Gentoo projects. It is explicitly enforced for all official Gentoo projects in order to protect the interests of Gentoo as a whole, including its contributors, developers and users. Additionally, it is enforced for all other projects hosted on Gentoo infrastructure in order to protect the Gentoo infrastructure owners and improve consistency.

The copyright model is built on the DCO model used by the Linux kernel and requires all contributors to certify the legitimacy of their contributions. This also requires that they use a known identity for signing; an anonymous certification would not mean anything. This policy is derived from the Linux project's policy as of 2023-02-27 [9].

In the future, a second stage of this policy may use a combination of the DCO model and an FLA model [1] as it is used by different open source projects. Contributors would be able to freely choose whether they sign the FLA document or not.

After Gentoo Linux has become an associated project of Software in the Public Interest (SPI) [10], the Gentoo Council will be responsible for granting of license exceptions and resolution of copyright issues, instead of the Gentoo Foundation Trustees. The Council may confer with SPI for issues that it cannot resolve itself.

Licensing of Projects

The Social Contract mentions GPL-2 and CC-BY-SA-2.0, both with the option to use them in a later version ("at our discretion"). In order to facilitate interchange of software between different projects, we aim for uniformity of their licensing. Therefore, items a) and b) explicitly recommend the use of GPL-2+ and CC-BY-SA-4.0. The latter is restricted to be used for documentation, because Creative Commons themselves recommend against using their licenses for software [11].

Other GPL-compatible free software licenses that are not explicitly listed are allowed by item c). This covers cases where compatibility to licenses used by upstream projects is necessary. (For example, the Gentoo BSD project may want to use the 2-clause or 3-clause BSD license.)

By default, GPL-incompatible licenses (e.g., the CDDL) are not allowed, because their use would hinder interchange of code between Gentoo projects. However, the Council can grant exceptions to this, as long as the license in question is a free software or open source license.

Changes to the Certificate of Origin

The Gentoo Certificate of Origin rev. 1 has been based on Linux Kernel DCO 1.1 [7]. It features the following modifications from the original:

1. The enumeration has been modified to use numeric points.

2. Additional point 3. has been inserted:

   3. The contribution is a license text (or a file of similar nature), and verbatim distribution is allowed; or

3. The original point (c) has shifted to become point 4., and has been updated to account for the additional point 3.

4. The original point (d) has been transformed into a stand-alone paragraph following the enumeration.

5. The term "open source" has been replaced by "free software" throughout.

The new point was deemed necessary to allow committing license files into the Gentoo repository, since those files usually do not permit modification. It has been established that adding a clear provision for this case is better than excluding those commits from compliance with the Certificate of Origin. Debian was facing a similar problem [12].

The update of point (c) was necessary to allow the new clause being certified by the person providing the contribution.

The term "free software" is used for consistency with the language of the Gentoo Social Contract [2].

The remaining changes were merely editorial. The original point (d) is not part of the or statement joining the other points, so keeping it in a paragraph separate from the enumeration is more appropriate.

Addition of another point for public domain material was also considered. However, it is preferred if all contributions carry an explicit license notice that allows their certification under point 1. or 2. If necessary, license tools like Creative Commons CC0 [13] or Public Domain Mark [14] can be used.

Copyright Notice

Especially for ebuild repositories, constantly keeping track of the main copyright holder of any file would be rather inconvenient and tedious. Therefore, projects are free to use either a traditional copyright notice listing the individual author(s), or a simplified notice with an attribution to the "Gentoo Authors". The latter resembles the scheme used by the Chromium project [15].