Note that as an alternative to openssl there's gnutls which is lgpl2+ and thus is compatible - but only for dynamic linking, proprietary applications statically linking to libzmq thanks to it's exception will not be able to statically link to gnutls.
On Tue, 25 Dec 2018, 21:13 Luca Boccassi <[email protected] wrote: > On Tue, 2018-12-25 at 21:05 +0100, 林宝龙 wrote: > > I suggested to use curve directly, but as a hole system, they didn't > > want > > to have two key management system, TLS was there which was used by > > other > > node. And another reason they gave to me is the curve was not been > > used so > > much by big companies compare to TLS, even it's simple than TLS. > > Further > > more the running environment has already had OpenSSL installed, use > > openssl > > can lower the security libraries maintenance. > > First of all curve was created by expert cryptographers, and it's > extensively used, so it's not really a problem. The crypto primitives > are provides by libsodium, which again is a very high quality library > and used by many, many applications and libraries, and will most likely > be already installed everywhere. > > Regarding key management, are you aware that there's the ZAP protocol? > You can use it to implement the key management scheme you prefer, > programmatically. For example, you could map 1:1 from SSL keys to curve > keys internally. > > > About the license problem, as you explained to me, it is a big > > problem, I > > saw there is an issue which was registered 2 years ago to change the > > libzmq's license, but it is not coming to end. I'll check with my > > colleagues how to make the license issue gone? Come back to you when > > I > > have more information. > > Again - you *cannot* make the license issue go away. We have been > trying to relicense to MPL2 for years, it will take years to finish, if > ever. This is not something that can be worked around or "hacked". It's > a legal issue. > > > Best regards, > > Baolong > > > > On Tue, 25 Dec 2018, 12:31 Luca Boccassi <[email protected] > > wrote: > > > > > On Tue, 2018-12-25 at 00:53 +0100, 林宝龙 wrote: > > > > The problem of first option we met is that OpenSSL provides a lot > > > > configurable things, for example, trust group, external > > > > verification > > > > callback, etc. We must add more options to sockopt to have such > > > > things > > > > configurable. For the callback functions, if we continue using > > > > setsockopt, > > > > we need to cast function pointer to void pointer and vice versa, > > > > looks not > > > > good. > > > > > > As mentioned, there is really no alternative to continue supporting > > > bindings. Also, exposing a third party API/ABI again would mean > > > that > > > the users would need to start worrying about OpenSSL's API/ABI > > > changes, > > > and keep them in sync with the internal usage of the library. That > > > would not be maintainable. > > > > > > So it looks like there are both legal and implementation problems. > > > So > > > let's take a step back: why is the current > > > encryption/authentication > > > support via CURVE and GSSAPI not sufficient? What is lacking that > > > you > > > need in your application? > > > > > > > About the licence issue, I'm not familiar with those licenses, > > > > and I > > > > have > > > > asked someone inside my company, got the answer that I can use > > > > OpenSSL in > > > > libzmq with an exception, I don't know how. He said that we will > > > > share the > > > > code out in the end, but can't contribute back to libzmq > > > > directly. > > > > Does it > > > > same as what you concern? Do you have more information that we > > > > must > > > > stop > > > > using OpenSSL inside libzmq? > > > > > > Yes an exception is needed as I said, but not just from you: from > > > every > > > single copyright holder of libzmq, of which there are many. That's > > > because adding an exception to the license is a change in license, > > > and > > > cannot legally be done unilaterally. > > > > > > Note that this is not only a problem for contributing code back, > > > but > > > also for your application. You cannot distribute those changes to > > > anybody without a license change, which means you cannot give your > > > application to anybody without breaching the terms of the license, > > > and > > > thus copyright law. > > > > > > > On Mon, 24 Dec 2018, 23:42 Luca Boccassi <[email protected] > > > > wrote: > > > > > > > > > On Mon, 24 Dec 2018, 23:03 林宝龙 <[email protected] wrote: > > > > > > > > > > > Hi, > > > > > > > > > > > > We are adding TLS support for ZeroMQ(based on 4.2.5). Product > > > > > > reason, we > > > > > > choosed OpenSSL as TLS library. > > > > > > > > > > > > Ask community for suggestions, which solution below is > > > > > > better? > > > > > > 1. Use TLS public certification, private key, etc as socket > > > > > > option (set > > > > > > through setsockopt), ZeroMQ manages the OpenSSL context, > > > > > > one OpenSSL > > > > > > context per socket_base_t object. > > > > > > 2. Use OpenSSL context as socket option(set through > > > > > > setsockopt), > > > > > > external > > > > > > application should provide the OpenSSL context, with public > > > > > > certification, > > > > > > private key, etc. set in context level, all ssl connections > > > > > > share > > > > > > the same > > > > > > configuration as the input OpenSSL context. > > > > > > > > > > > > At beginning we choosed the first solution, like curve, use > > > > > > public > > > > > > certification, private key as the socket option. But later > > > > > > on, we > > > > > > found the > > > > > > second solution that use external OpenSSL context can make > > > > > > the > > > > > > ZeroMQ code > > > > > > simpler, and more flexible, external application can > > > > > > configure > > > > > > the OpenSSL > > > > > > context without change the ZeroMQ socket options. > > > > > > > > > > > > Welcome your comments. > > > > > > > > > > > > Best regards, > > > > > > Baolong > > > > > > > > > > > > > > > > The first option would be better, exposing third party API and > > > > > ABI > > > > > would > > > > > be a nightmare, especially for bindings. O > > > > > > > > > > But the most important issue is that the Openssl license is not > > > > > compatible > > > > > with libzmq, which is licensed under the lgpl3, so I'm afraid > > > > > such > > > > > combination will not be legally distributable. At least not > > > > > without > > > > > a > > > > > relicensing effort to add an exception - we are already trying > > > > > that > > > > > to > > > > > change to mpl2 and are nowhere near done unfortunately. > > > > > > > > > > > _______________________________________________ > > > > > > > > > > zeromq-dev mailing list > > > > > [email protected] > > > > > https://lists.zeromq.org/mailman/listinfo/zeromq-dev > > > > > > > > > > > > > _______________________________________________ > > > > zeromq-dev mailing list > > > > [email protected] > > > > https://lists.zeromq.org/mailman/listinfo/zeromq-dev > > > > > > -- > > > Kind regards, > > > Luca Boccassi_______________________________________________ > > > zeromq-dev mailing list > > > [email protected] > > > https://lists.zeromq.org/mailman/listinfo/zeromq-dev > > > > > > > _______________________________________________ > > zeromq-dev mailing list > > [email protected] > > https://lists.zeromq.org/mailman/listinfo/zeromq-dev > > -- > Kind regards, > Luca Boccassi
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