|
@@ -1,128 +0,0 @@
|
|
|
-License Mixing
|
|
|
-==============
|
|
|
-
|
|
|
-libcurl can be built to use a fair amount of various third party libraries,
|
|
|
-libraries that are written and provided by other parties that are distributed
|
|
|
-using their own licenses. Even libcurl itself contains code that may cause
|
|
|
-problems to some. This document attempts to describe what licenses libcurl and
|
|
|
-the other libraries use and what possible dilemmas linking and mixing them all
|
|
|
-can lead to for end users.
|
|
|
-
|
|
|
-I am not a lawyer and this is not legal advice!
|
|
|
-
|
|
|
-One common dilemma is that [GPL](https://www.gnu.org/licenses/gpl.html)
|
|
|
-licensed code is not allowed to be linked with code licensed under the
|
|
|
-[Original BSD license](https://spdx.org/licenses/BSD-4-Clause.html) (with the
|
|
|
-announcement clause). You may still build your own copies that use them all,
|
|
|
-but distributing them as binaries would be to violate the GPL license - unless
|
|
|
-you accompany your license with an
|
|
|
-[exception](https://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs). This
|
|
|
-particular problem was addressed when the [Modified BSD
|
|
|
-license](https://opensource.org/licenses/BSD-3-Clause) was created, which does
|
|
|
-not have the announcement clause that collides with GPL.
|
|
|
-
|
|
|
-## libcurl
|
|
|
-
|
|
|
- Uses an [MIT style license](https://curl.haxx.se/docs/copyright.html) that is
|
|
|
- very liberal.
|
|
|
-
|
|
|
-## OpenSSL
|
|
|
-
|
|
|
- (May be used for SSL/TLS support) Uses an Original BSD-style license with an
|
|
|
- announcement clause that makes it "incompatible" with GPL. You are not
|
|
|
- allowed to ship binaries that link with OpenSSL that includes GPL code
|
|
|
- (unless that specific GPL code includes an exception for OpenSSL - a habit
|
|
|
- that is growing more and more common). If OpenSSL's licensing is a problem
|
|
|
- for you, consider using another TLS library.
|
|
|
-
|
|
|
-## GnuTLS
|
|
|
-
|
|
|
- (May be used for SSL/TLS support) Uses the
|
|
|
- [LGPL](https://www.gnu.org/licenses/lgpl.html) license. If this is a problem
|
|
|
- for you, consider using another TLS library. Also note that GnuTLS itself
|
|
|
- depends on and uses other libs (libgcrypt and libgpg-error) and they too are
|
|
|
- LGPL- or GPL-licensed.
|
|
|
-
|
|
|
-## WolfSSL
|
|
|
-
|
|
|
- (May be used for SSL/TLS support) Uses the GPL license or a proprietary
|
|
|
- license. If this is a problem for you, consider using another TLS library.
|
|
|
-
|
|
|
-## NSS
|
|
|
-
|
|
|
- (May be used for SSL/TLS support) Is covered by the
|
|
|
- [MPL](https://www.mozilla.org/MPL/) license, the GPL license and the LGPL
|
|
|
- license. You may choose to license the code under MPL terms, GPL terms, or
|
|
|
- LGPL terms. These licenses grant you different permissions and impose
|
|
|
- different obligations. You should select the license that best meets your
|
|
|
- needs.
|
|
|
-
|
|
|
-## mbedTLS
|
|
|
-
|
|
|
- (May be used for SSL/TLS support) Uses the [Apache 2.0
|
|
|
- license](https://opensource.org/licenses/Apache-2.0) or the GPL license.
|
|
|
- You may choose to license the code under Apache 2.0 terms or GPL terms.
|
|
|
- These licenses grant you different permissions and impose different
|
|
|
- obligations. You should select the license that best meets your needs.
|
|
|
-
|
|
|
-## BoringSSL
|
|
|
-
|
|
|
- (May be used for SSL/TLS support) As an OpenSSL fork, it has the same
|
|
|
- license as that.
|
|
|
-
|
|
|
-## libressl
|
|
|
-
|
|
|
- (May be used for SSL/TLS support) As an OpenSSL fork, it has the same
|
|
|
- license as that.
|
|
|
-
|
|
|
-## BearSSL
|
|
|
-
|
|
|
- (May be used for SSL/TLS support) Uses an MIT license that is very liberal
|
|
|
- and imposes no restrictions on any other library or part you may link with.
|
|
|
-
|
|
|
-## c-ares
|
|
|
-
|
|
|
- (Used for asynchronous name resolves) Uses an MIT license that is very
|
|
|
- liberal and imposes no restrictions on any other library or part you may link
|
|
|
- with.
|
|
|
-
|
|
|
-## zlib
|
|
|
-
|
|
|
- (Used for compressed Transfer-Encoding support) Uses an MIT-style license
|
|
|
- that shouldn't collide with any other library.
|
|
|
-
|
|
|
-## MIT Kerberos
|
|
|
-
|
|
|
- (May be used for GSS support) MIT licensed, that shouldn't collide with any
|
|
|
- other parts.
|
|
|
-
|
|
|
-## Heimdal
|
|
|
-
|
|
|
- (May be used for GSS support) Heimdal is Original BSD licensed with the
|
|
|
- announcement clause.
|
|
|
-
|
|
|
-## GNU GSS
|
|
|
-
|
|
|
- (May be used for GSS support) GNU GSS is GPL licensed. Note that you may not
|
|
|
- distribute binary curl packages that uses this if you build curl to also link
|
|
|
- and use any Original BSD licensed libraries!
|
|
|
-
|
|
|
-## libidn
|
|
|
-
|
|
|
- (Used for IDNA support) Uses the GNU Lesser General Public License [3]. LGPL
|
|
|
- is a variation of GPL with slightly less aggressive "copyleft". This license
|
|
|
- requires more requirements to be met when distributing binaries, see the
|
|
|
- license for details. Also note that if you distribute a binary that includes
|
|
|
- this library, you must also include the full LGPL license text. Please
|
|
|
- properly point out what parts of the distributed package that the license
|
|
|
- addresses.
|
|
|
-
|
|
|
-## OpenLDAP
|
|
|
-
|
|
|
- (Used for LDAP support) Uses a Modified BSD-style license. Since libcurl uses
|
|
|
- OpenLDAP as a shared library only, I have not heard of anyone that ships
|
|
|
- OpenLDAP linked with libcurl in an app.
|
|
|
-
|
|
|
-## libssh2
|
|
|
-
|
|
|
- (Used for scp and sftp support) libssh2 uses a Modified BSD-style license.
|