[dm-crypt] License Clarification

Nathaniel McCallum npmccallum at redhat.com
Mon Nov 14 22:47:11 CET 2016

Thanks for the response. My particular concern is the ability to link
to both libcryptsetup and openssl higher up in the stack.

On Mon, Nov 14, 2016 at 3:22 PM, Milan Broz <gmazyland at gmail.com> wrote:
> The original intention is documented here
> http://www.saout.de/pipermail/dm-crypt/2012-December/002992.html
> Anyway, I have contacted lawyers to check it and for possible
> guidance if a fix is needed.
> Thanks,
> Milan
> On 11/10/2016 08:41 PM, Nathaniel McCallum wrote:
>> In reviewing the license choices of a set of my projects, I have
>> noticed an inconsistency in licensing and I would like to receive some
>> clarification.
>> There is a commit that changes some of the code to LGPLv2.1+:
>> https://gitlab.com/cryptsetup/cryptsetup/commit/7eccb7ff5031a4f42f1ae8f7ffaefe80ba0d53dd
>> However, the main header still reads GPLv2+:
>> https://gitlab.com/cryptsetup/cryptsetup/blob/master/lib/libcryptsetup.h
>> Further, the API examples have LGPLv2.1+:
>> https://gitlab.com/cryptsetup/cryptsetup/wikis/API/index.html
>> Again, the openssl crypto backend are licensed as LGPLv2.1+ w/ openssl
>> exception. However, this exception doesn't seem to apply to the whole
>> library:
>> https://gitlab.com/cryptsetup/cryptsetup/blob/master/lib/crypto_backend/crypto_openssl.c
>> In short, it is very unclear to me how this licensing is supposed to work.
>> The best I can ascertain is this:
>> crypto-backend (LGPLv2+) ==> libcryptsetup (GPLv2+) ==> API examples (LGPLv2+)
>> It would, thus, seem to me that the API examples are incompatibly
>> licensed and cannot actually link against libcryptsetup.
>> Further, it seems to me that the crypto-backend can link against
>> openssl, but not libcryptsetup itself. This further implies that
>> consumers of libcryptsetup cannot link against openssl.
>> Have I understood this correctly?
>> _______________________________________________
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>> dm-crypt at saout.de
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