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Copyright law is complex, OpenBSD policy is simple - OpenBSD strives to maintain the spirit of the original Berkeley unix copyrights.
OpenBSD can exist as it does today because of the example set by the Computer Systems Research Group at Berkeley and the battles which they and others fought to create a relatively un-encumbered unix source distribution.
The ability of a freely redistributable "Berkeley" unix to move forward on a competitive basis with other operating systems depends on the willingness of the various development groups to exchange code amongst themselves and with other projects. Understanding the the legal issues surrounding copyright is fundamental to the ability to exchange and re-distribute code, while honoring the spirit of the copyright and concept of attribution is fundamental to promoting the cooperation of the people involved.
Because the OpenBSD copyright imposes no conditions beyond those imposed by the Berkeley copyright, OpenBSD can hope to share the same wide distribution and applicability as the Berkeley distributions. It follows however, that OpenBSD can not include material which includes copyrights which are more restrictive than the Berkeley copyright, or must relegate this material to a secondary status, i.e. OpenBSD as a whole is freely redistributable, but some optional components may not be.
While the overall subject of copyright law is far beyond the scope of this document, some basics are in order. Under the current copyright law, copyrights are implicit in the creation of a new work and reside with the creator, unless otherwise assigned. In general the copyright applies only to the new work, not the material the work was derived from, nor those portions of the derivative material included in the new work.
Copyright law admits to three general categories of works:
It is vitally important to understand that copyrights are broad protections as defined by national and international copyright law. The "copyright notices" usually included in source files are not copyrights, but rather notices that a party asserts that they hold copyright to the material or to part of the material. Typically these notices are associcated with license terms which grant permissions subject to copyright law and with disclaimers that state the position of the copyright holder/distributor with respect to liability surrounding use of the material.
Again, an important point to note is that the release and conditions can only apply to the portion of the work that was originated by the copyright holder - the holder of a copyright on a derivative work can neither grant additional permissions for use of the original work, nor impose more restrictive conditions for use of that work.
Because copyright arises from the creation of a work and not the text or a registration process, removing or altering a copyright notice or associated release terms has no bearing on the existance of the copyright, rather all that is accomplished to whatever rights the person making the modifications had to use the material in the first place. Likewise, adding terms and conditions in conflict with the original terms and conditions does not supercede them, rather it casts doubts on the rights of the person making the amendments to use the material and creates confusion as to whether anyone can use amended version or derivitives thereof.
Finally, releases are generally binding on the material that they are distributed with. This means that if the originator of a work distributes that work with a release granting certain permissions, those permissions apply as stated, without discrimination, to all persons legitimately possessing a copy of the work. That means that having granted a permission, the copyright holder can not retroactively say that an individual or class of individuals are no longer granted those permissions. Likewise should the copyright holder decide to "go commercial" he can not revoke permissions already granted for the use of the work as distributed, though he may impose more restrictive permissions in his future distributions of that work.
This section attempts to summarize the position of OpenBSD relative to some commonly encountered copyrights.
The Berkeley copyright is the model for the OpenBSD copyright. It retains the rights of the copyright holder, while imposing minimal conditions on the use of the copyrighted material. Material with Berkeley copyrights, or copyrights closely adhering to the Berkeley model can generally be included in OpenBSD.
While AT&T holds the copyrights to much "unix" code and documentation, OpenBSD is based largely on Berkeley (BSD) distributions that contain only material known to be free of AT&T copyrights, or material to which AT&T has abandoned it's copyright or included licensing terms similar to the Berkeley terms. No material subject to restrictive AT&T copyrights can be included in OpenBSD.
Examples of AT&T code, included subject to non-restrictive copyrights, include some system sources such as init_main.c and the AT&T version of awk.
In general OpenBSD does not include material copyrighted by manufacturers or software houses. Material may be included where the copyright owner has granted general permission for reuse without conditions, with terms similar to the Berkeley copyright, or where the material is the product of an employee and the employer's copyright notice is effectively releases any rights they might have to the work.
The Carnegie-Mellon copyright is similar to the Berkeley copyright, except that it requests that derivative works be made available to Carnegie-Mellon. Because this is only a request and not a condition, such material can still be included in OpenBSD. It should be noted that existing versions of Mach are still subject to AT&T copyrights, which prevents the general distribution of Mach sources.
The GNU Public License and licenses modeled on it impose the restriction that source code must be distributed or made available for all works that are derivatives of the GNU copyrighted code.
While this may be a noble strategy in terms of software sharing, it is a condition that is typically unacceptable for commercial use of software. As a consequence, software bound by the GPL terms can not be included in the kernel or "runtime" of of OpenBSD, though software subject to GPL terms may be included as development tools or as part of the system at are "optional" as long as such use does not result in OpenBSD as a whole becoming subject to the GPL terms.
As an example, some ports include GNU Floating Point Emulation - this is optional and the system can be built without it or with an alternative emulation package. Another example is the use GCC and other GNU tools in the OpenBSD tool chain - it is quite possible to distribute a system for many applications without a tool chain, or the distributor can choose to include a tool chain as optional bundle which conforms to the GPL terms.
Much of OpenBSD is orignally based on and evolveed from NetBSD, since some of the OpenBSD developers were involved in the NetBSD project. The general NetBSD license terms are compatible with the Berkeley license and permit such use. Material subject only to the general NetBSD license can generally be included in OpenBSD.
The current NetBSD distribution also includes material copyrighted by individuals who have imposed license conditions beyond that of the general NetBSD license, but granted the NetBSD Foundation license to distribute the material. Such material can not be included in OpenBSD as long as the conditions imposed are at odds with the OpenBSD license terms or releases from those terms are offered on a disciminatory basis.
Most of FreeBSD is also based on Berkeley licensed material or includes copyright notices based on the Berkeley model. Such material can be included in OpenBSD, while those parts that are subject to GPL or various individual copyright terms that are at odds with the OpenBSD license can not be included in OpenBSD.
Most of Linux is subject to GPL style licensing terms and therefore can not be included in OpenBSD. Individual components may be eligible, subject to the terms of the originator's copyright notices. Note that Linux "distributions" may also be subject additional copyright claims of the distributing organization, either as a compilation or on material included that is not part of the Linux core.
X and XFree86 are not parts of OpenBSD, rather X or Xfree86 is distributed with many OpenBSD ports as a convenience to the user, subject to applicable license terms.
Most "shareware" copyright notices impose conditions for redistribution, use or visibility that are at conflict with the OpenBSD project goals. Review on a case-by-case basis is required as to whether the wording of the conditions is acceptable in terms of conditions being requested vs. demanded and whether the spirit of the conditions is compatible with goals of the OpenBSD project.
While material that is truly entered into the "Public Domain" can be included in OpenBSD, review is required on a case by case basis. Frequently the "public domain" assertion is made by someone who does not really hold all rights under Copyright law to grant that status or there are a variety of conditions imposed on use. For a work to be truly in the "Public Domain" all rights are abandoned and the material is offered without restrictions.
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