Debian Policy 4.7.0.1, 2024-08-25
Abstract
Establishes a standard, machine-readable format for
debian/copyright
files within Debian packages
to facilitate automated checking and reporting of licenses for
packages and sets of packages. This specification was originally
drafted as
DEP-5.
Table of Contents
This document describes a standard, machine-interpretable format for
the debian/copyright
file. This file is one of
the most important files in Debian packaging, but, prior to this
specification, no standard format was defined for it and its
contents varied tremendously across packages. This made it
difficult to automatically extract licensing information.
Use of this specification is optional.
Nothing in this proposal supersedes or modifies any of the requirements
specified in Debian Policy regarding the appropriate detail or
granularity to use when documenting copyright and license status in
debian/copyright
.
The diversity of free software licenses means that Debian needs to care not only about the freeness of a given work, but also its license's compatibility with the other parts of Debian it uses.
The arrival of the GPL version 3, its incompatibility with version 2, and our inability to spot the software where the incompatibility might be problematic is one prominent occurrence of this limitation.
There are earlier precedents, also. One is the GPL/OpenSSL
incompatibility. Apart from grepping
debian/copyright
, which is prone to numerous false
positives (packaging under the GPL but software under another license) or
negatives (GPL software but with an “OpenSSL special
exception” dual licensing form), there is no reliable way to know
which software in Debian might be problematic.
And there is more to come. There are issues with shipping GPLv2-only software with a CDDL operating system such as Nexenta. The GPL version 3 solves this issue, but not all GPL software can switch to it and we have no way to know how much of Debian should be stripped from such a system.
Even where licenses are DFSG-free and mutually compatible, users may wish for a way to identify software under certain licenses (if, for example, they have special reasons to avoid certain licenses).
Many people have worked on this specification over the years. The following alphabetical list is incomplete; please suggest missing people: Russ Allbery, Ben Finney, Sam Hocevar, Steve Langasek, Charles Plessy, Noah Slater, Jonas Smedegaard, Lars Wirzenius.
The debian/copyright
file must be
machine-interpretable, yet human-readable, while communicating all
mandated upstream information, copyright notices and licensing details.
The syntax of the file is the same as for other Debian control files, as
specified in the Debian Policy Manual. See its section
5.1 for details. Extra fields can be added to any stanza. No
prefixing is necessary or desired, but please avoid names similar to
standard ones so that mistakes are easier to catch. Future versions of
the debian/copyright
specification will attempt to
avoid conflicting specifications for widely used extra fields.
The file consists of two or more stanzas. At minimum, the file must include one header stanza and one Files stanza.
There are four types of fields. The definition for each field in this document indicates which type of value it takes.
The entire value of a single-line field must be on a single line.
For example, the Format
field has a single-line
value specifying the version of the machine-readable format that
is used.
Field values defined as whitespace-separated lists may be on one
line or many. Values in the list are separated by one or more
whitespace characters (space, tab, or newline). For example, the
Files
field contains a whitespace-separated
list of filename patterns.
Line-based lists have one value per line. For example, the
Upstream-Contact
field contains a line-based
list of contact addresses.
Formatted text fields use the same rules as the long description
in a package's Description
field in Debian
control files.
In some but not all cases, the first line may have special
meaning as a synopsis, similar to how the
Description
field uses the first line for
the short description. See Debian Policy's section 5.6.13,
“Description”,
for details. For example, Disclaimer
is a
formatted text field that has no special first line, and
License
is a formatted text field where the
first line indicates the short name or names of the licenses.
There are three kinds of stanzas. The first stanza in the file
is called the header stanza.
Every other stanza is either a Files stanza or a stand-alone License
stanza. This is similar to source and binary package
stanzas in debian/control
files.
The following fields may be present in a header stanza.
Format: required.
Upstream-Name: optional.
Upstream-Contact: optional.
Source: optional.
Disclaimer: optional.
Comment: optional.
License: optional.
Copyright: optional.
The Copyright
and License
fields in the header stanza may complement
but do not replace the fields in the Files
stanzas. If present, they summarise the copyright
notices or redistribution terms for the package as a whole.
For example, when a work has a grant of license under both a
permissive and a copyleft license, License
can
be used to clarify the license terms for the combination.
Copyright
and License
together can also be used to document a compilation
copyright and license.
It is valid to use License
in the header
stanza without an accompanying Copyright
field, but Copyright
alone is not sufficient.
Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/ Source: https://www.example.com/software/project Upstream-Name: SOFTware Upstream-Contact: John Doe <[email protected]>
The declaration of copyright and license for files may consist of
one or more stanzas. In the simplest case, a single stanza
with Files: *
can be used to state the license
and copyright for the whole package. Only the license and
copyright information required by the Debian archive is required
to be listed here.
The following fields may be present in a Files stanza.
Files: * Copyright: 1975-2010 Ulla Upstream License: GPL-2+ Files: debian/* Copyright: 2010 Daniela Debianizer License: GPL-2+ Files: debian/patches/fancy-feature Copyright: 2010 Daniela Debianizer License: GPL-3+ Files: */*.1 Copyright: 2010 Manuela Manpager License: GPL-2+
In this example, copyright in all files is held by the upstream, and that copyright holder grants license under the GPL, version 2 or later. There are three exceptions. All the Debian packaging files have copyright held by the packager, and further one specific file providing a new feature has a different grant of license. Finally, there are some manual pages added to the package, with copyright held by a third person.
Since the license of the manual pages is the same as most other
files in the package, the final stanza above could instead be
combined with the first stanza, listing both copyright
statements in one Copyright
field. Whether to
combine stanzas with the same grant of license is left to the
discretion of the author of the
debian/copyright
file.
Stand-alone License
stanzas can be used to
provide the full license text for a given license once, instead of
repeating it in each Files
stanza that refers
to it.
The synopsis (on the first line) of the License
field must be a single license short name or a short name followed
by a license exception.
The following fields may be present in a stand-alone License stanza.
Example 1. tri-licensed files
Files: src/js/editline/* Copyright: 1993, John Doe 1993, Joe Average License: MPL-1.1 or GPL-2 or LGPL-2.1 License: MPL-1.1 [LICENSE TEXT] License: GPL-2 [LICENSE TEXT] License: LGPL-2.1 [LICENSE TEXT]
Example 2. recurrent license
Files: src/js/editline/* Copyright: 1993, John Doe 1993, Joe Average License: MPL-1.1 Files: src/js/fdlibm/* Copyright: 1993, J-Random Corporation License: MPL-1.1 License: MPL-1.1 [LICENSE TEXT]
The following fields are defined for use in
debian/copyright
.
Single-line: URI of the format specification. The field that should be used for the current version of this document is:
Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
The original version of this specification used the non-https version of this URL as its URI, namely:
Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Both versions are valid and refer to the same specification, and parsers should interpret both as referencing the same format. The https URI is preferred.
Line-based list: the preferred address(es) to reach the upstream project. May be free-form text, but by convention will usually be written as a list of RFC5322 addresses or URIs.
Formatted text, no synopsis: an explanation of where the upstream source came from. Typically this would be a URL, but it might be a free-form explanation. The Debian Policy section 12.5 requires this information unless there are no upstream sources, which is mainly the case for native Debian packages. If the upstream source has been modified to remove non-free parts, that should be explained in this field.
Formatted text, no synopsis: this field is used for non-free or contrib packages to state that they are not part of Debian and to explain why (see Debian Policy section 12.5).
Formatted text, no synopsis: this field can provide additional information. For example, it might quote an e-mail from upstream justifying why the license is acceptable to the main archive, or an explanation of how this version of the package has been forked from a version known to be DFSG-free, even though the current upstream version is not.
Formatted text, with synopsis.
In the header stanza,
this field gives the license information for the package as a
whole, which may be different or simplified from a combination of
all the per-file license information. In a Files stanza, this field gives
the licensing terms for the files listed in the
Files
field for this stanza. In a stand-alone License
stanza, it gives the licensing terms for those
stanzas which reference it.
First line (synopsis): an abbreviated name for the license, or expression giving alternatives (see the Short name section for a list of standard abbreviations). If there are licenses present in the package without a standard short name, an arbitrary short name may be assigned for these licenses. These arbitrary names are only guaranteed to be unique within a single copyright file.
If there are no remaining lines, then all of the short names or
short names followed by license exceptions in the synopsis must be
described in stand-alone License
stanzas. Otherwise, this field should either include the
full text of the license(s) or include a pointer to the license
file under /usr/share/common-licenses
. This
field should include all text needed in order to fulfill both
Debian Policy's requirement for including a copy of the software's
distribution license (12.5),
and any license requirements to include warranty disclaimers or
other notices with the binary package.
Formatted text, no synopsis: one or more free-form copyright
statements. Any formatting is permitted; see the examples below
for some ideas for how to structure the field to make it easier to
read. In the header stanza, this field gives the copyright
information for the package as a whole, which may be different or
simplified from a combination of all the per-file copyright
information. In the Files stanzas, it gives the copyright
information that applies to the files matched by the
Files
pattern. If a work has no copyright holder
(i.e., it is in the public domain), that information should be
recorded here.
The Copyright
field collects all relevant
copyright notices for the files of this stanza. Not all
copyright notices may apply to every individual file, and years of
publication for one copyright holder may be gathered together. For
example, if file A has:
Copyright 2008 John Smith Copyright 2009 Angela Watts
and file B has:
Copyright 2010 Angela Watts
a single stanza may still be used for both files. The
Copyright
field for that stanza would
contain:
Copyright 2008 John Smith Copyright 2009, 2010 Angela Watts
The Copyright
field may contain the original
copyright statement copied exactly (including the word
“Copyright”), or it may shorten the text or merge it
with other copyright statements as described above, as long as it
does not sacrifice information. Examples in this specification use
both forms.
Whitespace-separated list: list of patterns indicating files covered by the license and copyright specified in this stanza.
Filename patterns in the Files
field are
specified using a simplified shell glob syntax. Patterns are
separated by whitespace.
Only the wildcards *
and ?
apply; the former matches any number of characters (including
none), the latter a single character. Both match slashes
(/
) and leading dots, unlike shell globs.
The pattern *.in
therefore matches any
file whose name ends in .in
anywhere in
the source tree, not just at the top level.
Patterns match pathnames that start at the root of the source
tree. Thus, “Makefile.in
”
matches only the file at the root of the tree, but
“*/Makefile.in
” matches at
any depth.
The backslash (\
) is used to remove the
magic from the next character; see table below.
Escape sequence | Matches |
---|---|
\* | star (asterisk) |
\? | question mark |
\\ | backslash |
Any other character following a backslash is an error.
This is the same pattern syntax as
fnmatch(3) without the
FNM_PATHNAME
flag, or the argument to the
-path
test of the GNU find
command, except that []
wildcards are not
recognized.
Multiple Files
stanzas are allowed. The last
stanza that matches a particular file applies to it. More
general stanzas should therefore be given first, followed by
more specific overrides.
Exclusions are only supported by adding Files
stanzas to override the previous match.
This syntax does not distinguish file names from directory names; a trailing slash in a pattern will never match any actual path. A whole directory tree may be selected with a pattern like "foo/*".
The space character, used to separate patterns, cannot be escaped with a backslash. A path like "foo bar" may be selected with a pattern like "foo?bar".
Much of the value of a machine-parseable copyright file lies in being
able to correlate the licenses of multiple pieces of software. To that
end, this spec defines standard short names for a number of commonly
used licenses, which can be used in the synopsis (first line) of a
License
field.
These short names have the specified meanings across all uses of this file format, and must not be used to refer to any other licenses. Parsers may thus rely on these short names referring to the same licenses wherever they occur, without needing to parse or compare the full license text.
From time to time, licenses may be added to or removed from the list of
standard short names. Such changes in the list of short names will
always be accompanied by changes to the version of this standard
and to the recommended
Format
value. Implementers who are parsing copyright
files should take care not to assume anything about the meaning of
license short names for unknown Format
versions.
Use of a standard short name does not override the Debian Policy
requirement to include the full license text in
debian/copyright
, nor any requirements in the
license of the work regarding reproduction of legal notices. This
information must still be included in the License
field, either in a stand-alone License stanza or in the relevant
files stanza.
For licenses that have multiple versions in use, the short name is
formed from the general short name of the license family, followed
by a dash and the version number. If the version number is
omitted, the lowest version number is implied. When the license
grant permits using the terms of any later version of that
license, add a plus sign to the end of the short name. For
example, the short name GPL
refers to the GPL
version 1 and is equivalent to GPL-1
, although
the latter is clearer and therefore preferred. If the package may
be distributed under the GPL version 1 or any later version, use a
short name of GPL-1+
.
For SPDX compatibility, versions with trailing dot-zeroes are considered to be equivalent to versions without (e.g., “2.0.0” is considered equal to “2.0” and “2”).
Currently, the full text of the licenses is only available in the SPDX Open Source License Registry.
Keyword | Meaning |
---|---|
public-domain | No license required for any purpose; the work is not subject to copyright in any jurisdiction. |
Apache | Apache license 1.0, 2.0. |
Artistic | Artistic license 1.0, 2.0. |
BSD-2-clause | Berkeley software distribution license, 2-clause version. |
BSD-3-clause | Berkeley software distribution license, 3-clause version. |
BSD-4-clause | Berkeley software distribution license, 4-clause version. |
ISC | Internet Software Consortium, sometimes also known as the OpenBSD License. |
CC-BY | Creative Commons Attribution license 1.0, 2.0, 2.5, 3.0. |
CC-BY-SA | Creative Commons Attribution Share Alike license 1.0, 2.0, 2.5, 3.0. |
CC-BY-ND | Creative Commons Attribution No Derivatives license 1.0, 2.0, 2.5, 3.0. |
CC-BY-NC | Creative Commons Attribution Non-Commercial license 1.0, 2.0, 2.5, 3.0. |
CC-BY-NC-SA | Creative Commons Attribution Non-Commercial Share Alike license 1.0, 2.0, 2.5, 3.0. |
CC-BY-NC-ND | Creative Commons Attribution Non-Commercial No Derivatives license 1.0, 2.0, 2.5, 3.0. |
CC0 | Creative Commons Zero 1.0 Universal. Omit “Universal” from the license version when forming the short name. |
CDDL | Common Development and Distribution License 1.0. |
CPL | Common Public License. |
EFL | The Eiffel Forum License 1.0, 2.0. |
Expat | The Expat license. |
GPL | GNU General Public License 1.0, 2.0, 3.0. |
LGPL | GNU Lesser General Public License 2.1, 3.0, or GNU Library General Public License 2.0. |
GFDL | GNU Free Documentation License 1.0, 1.1, 1.2, or 1.3. Use GFDL-NIV instead if there are no Front-Cover or Back-Cover Texts or Invariant Sections. |
GFDL-NIV | GNU Free Documentation License, with no Front-Cover or Back-Cover Texts or Invariant Sections. Use the same version numbers as GFDL. |
LPPL | LaTeX Project Public License 1.0, 1.1, 1.2, 1.3c. |
MPL | Mozilla Public License 1.1. |
Perl |
Perl license
(use “GPL-1+ or Artistic-1 ”
instead).
|
Python | Python license 2.0. |
QPL | Q Public License 1.0. |
W3C | W3C Software License For more information, consult the W3C Intellectual Rights FAQ. |
Zlib | zlib/libpng license. |
Zope | Zope Public License 1.0, 1.1, 2.0, 2.1. |
There are many versions of the MIT license. Please use Expat instead, when it matches.
An exception or clarification to a license is signalled in plain text,
by appending with
to the short name. This document provides a list
of keywords that must be used when referring to the most frequent
exceptions. When exceptions other than these are in effect that
modify a common license by granting additional permissions, you may
use an arbitrary keyword not taken from the below list of keywords.
When a license differs from a common license because of added
restrictions rather than because of added permissions, a distinct
short name should be used instead of
exceptionkeywords
with
.
exceptionkeywords
Only one exception may be specified for each license within a given license specification. If more than one exception applies to a single license, an arbitrary short name indicating that combination of multiple exceptions must be used instead.
The GPL Font
exception refers to the text added to
the license notice of each file as specified at How does the
GPL apply to fonts. The precise text corresponding to this
exception is:
As a special exception, if you create a document which uses this font, and embed this font or unaltered portions of this font into the document, this font does not by itself cause the resulting document to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the document might be covered by the GNU General Public License. If you modify this font, you may extend this exception to your version of the font, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.
The GPL OpenSSL
exception gives permission to
link GPL-licensed code with the OpenSSL library, which contains
GPL-incompatible clauses. For more information, see The OpenSSL
License and The GPL by Mark McLoughlin and the message
middleman
software license conflicts with OpenSSL by Mark McLoughlin
on the debian-legal mailing list. The text
corresponding to this exception is:
In addition, as a special exception, the copyright holders give permission to link the code of portions of this program with the OpenSSL library under certain conditions as described in each individual source file, and distribute linked combinations including the two. You must obey the GNU General Public License in all respects for all of the code used other than OpenSSL. If you modify file(s) with this exception, you may extend this exception to your version of the file(s), but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. If you delete this exception statement from all source files in the program, then also delete it here.
The License
short name
public-domain
does not refer to a set of license
terms. There are some works which are not subject to copyright in
any jurisdiction and therefore no license is required for any
purpose covered by copyright law. This short name is an explicit
declaration that the associated files are “in the public
domain”.
Widespread misunderstanding about copyright in general, and the public domain in particular, results in the common assertion that a work is in the public domain when this is partly or wholly untrue for that work. The Wikipedia article on public domain is a useful reference for this subject.
When the License
field in a stanza has the
short name public-domain
, the remaining lines of
the field must explain exactly what exemption
the corresponding files for that stanza have from default
copyright restrictions.
License names are case-insensitive, and may not contain spaces.
In case of multi-licensing, the license short names are separated by
or
when the user can chose between different
licenses, and by and
when use of the work must
simultaneously comply with the terms of multiple licenses.
For instance, this is a simple, “GPL version 2 or later” field:
License: GPL-2+
This is a dual-licensed GPL/Artistic work such as Perl:
License: GPL-1+ or Artistic
This is for a file that has both GPL and classic BSD code in it:
License: GPL-2+ and BSD-3-clause
For the most complex cases, a comma is used to disambiguate the
priority of or
s and and
s.
The conjunction “and
” has priority over
“or
” unless preceded by a comma. For
instance:
A or B and C
means A or (B and C)
.
A or B, and C
means (A or B) and
C
.
This is for a file that has Perl code and classic BSD code in it:
License: GPL-2+ or Artistic-2.0, and BSD-3-clause
A GPL-2+
work with the OpenSSL
exception is in effect a dual-licensed work that can be redistributed
either under the GPL-2+
, or under the
GPL-2+
with the OpenSSL
exception. It is thus expressed as GPL-2+ with OpenSSL
exception
. A possible License
field for
such a license is:
License: GPL-2+ with OpenSSL exception This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. . In addition, as a special exception, the author of this program gives permission to link the code of its release with the OpenSSL project's "OpenSSL" library (or with modified versions of it that use the same license as the "OpenSSL" library), and distribute the linked executables. You must obey the GNU General Public License in all respects for all of the code used other than "OpenSSL". If you modify this file, you may extend this exception to your version of the file, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. . This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. . You should have received a copy of the GNU General Public License along with this package; if not, see <https://www.gnu.org/licenses/>. Comment: On Debian systems, the full text of the GNU General Public License version 2 can be found in the file '/usr/share/common-licenses/GPL-2'.
SPDX is an attempt to standardize
a format for communicating the components, licenses and copyrights
associated with a software package. It and the machine-readable
debian/copyright
format attempt to be somewhat
compatible. However, the two formats have different aims, and so the
formats are different. The DEP5 wiki
page will be used to track the differences.
Example 3. Simple
A possible debian/copyright
file for an
program “X Solitaire” distributed in the Debian
source package xsol
(this is not a complete or
correct copyright file for the actual xsol
package):
Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/ Source: ftp://ftp.example.com/pub/games Upstream-Name: X Solitaire Files: * Copyright: 1998 John Doe <[email protected]> 1998 Jane Smith <[email protected]> License: GPL-2+ This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. . This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. . You should have received a copy of the GNU General Public License along with this package; if not, see <https://www.gnu.org/licenses/>. Comment: On Debian systems, the full text of the GNU General Public License version 2 can be found in the file '/usr/share/common-licenses/GPL-2'.
Example 4. Complex
A possible debian/copyright
file for the program
“Planet Venus”, distributed in the Debian source
package planet-venus
(this is not a complete or
correct copyright file for the actual
planet-venus
package):
Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/ Source: https://www.example.com/code/venus Upstream-Name: Planet Venus Upstream-Contact: John Doe <[email protected]> Files: * Copyright: 2008, John Doe <[email protected]> 2007, Jane Smith <[email protected]> 2007, Joe Average <[email protected]> 2007, J. Random User <[email protected]> License: PSF-2 Files: debian/* Copyright: 2008, Dan Developer <[email protected]> License: permissive Copying and distribution of this package, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. Files: debian/patches/theme-diveintomark.patch Copyright: 2008, Joe Hacker <[email protected]> License: GPL-2+ Files: planet/vendor/compat_logging/* Copyright: 2002, Mark Smith <[email protected]> License: MIT [LICENSE TEXT] Files: planet/vendor/httplib2/* Copyright: 2006, John Brown <[email protected]> License: MIT2 Unspecified MIT style license. Files: planet/vendor/feedparser.py Copyright: 2007, Mike Smith <[email protected]> License: PSF-2 Files: planet/vendor/htmltmpl.py Copyright: 2004, Thomas Brown <[email protected]> License: GPL-2+ License: PSF-2 [LICENSE TEXT] License: GPL-2+ This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. . This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. . You should have received a copy of the GNU General Public License along with this package; if not, see <https://www.gnu.org/licenses/>. Comment: On Debian systems, the full text of the GNU General Public License version 2 can be found in the file '/usr/share/common-licenses/GPL-2'.