On Tue, Nov 16, 2021 at 2:16 AM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote: > > On 11/15/21 7:20 PM, Martin Kelly wrote: > > Hi, > > > > I have a question regarding the dual licensing provision of bpftool. I > > understand that bpftool can be distributed as either GPL 2.0 or BSD 2-clause. > > That said, bpftool can also auto-generate BPF code that gets specified inline > > in the skeleton header file, and it's possible that the BPF code generated is > > GPL. What I'm wondering is what happens if bpftool generates GPL-licensed BPF > > code inside the skeleton header, so that you get a header like this: > > > > something.skel.h: > > /* this file is BSD 2-clause, by nature of dual licensing */ > > Fwiw, the generated header contains an SPDX identifier: > > /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ > /* THIS FILE IS AUTOGENERATED! */ > > > /* THIS FILE IS AUTOGENERATED! */ > > > > /* standard skeleton definitions */ > > > > ... > > > > s->data_sz = XXX; > > s->data = (void *)"\ > > <eBPF bytecode, produced by GPL 2.0 sources, specified in binary> > > "; > > > > My guess is that, based on the choice to dual-license bpftool, the header is > > meant to still be BSD 2-clause, and the s->data inline code's GPL license is > > not meant to change the licensing of the header itself, but I wanted to Yes, definitely that is the intent (but not a lawyer either). > > double-check, especially as I am not a lawyer. If this is indeed the intent, > > is there any opposition to a patch clarifying this more explicitly in > > Documentation/bpf/bpf_licensing.rst? > > Not a lawyer either, but my interpretation is that this point related to "packaging" > of BPF programs from the bpf_licensing.rst would apply here (given this is what it > does after all): > > Packaging BPF programs with user space applications > =================================================== > > Generally, proprietary-licensed applications and GPL licensed BPF programs > written for the Linux kernel in the same package can co-exist because they are > separate executable processes. This applies to both cBPF and eBPF programs. Yep. If someone packages proprietary BPF ELF into a skeleton, that doesn't make the BPF ELF suddenly GPL or BSD, I'd imagine.
