Re: [PATCH v2 bpf-next 00/18] BPF token

Andy Lutomirski
2023-06-09T18:32:38Z

On Wed, Jun 7, 2023, at 4:53 PM, Andrii Nakryiko wrote:
> This patch set introduces new BPF object, BPF token, which allows to delegate
> a subset of BPF functionality from privileged system-wide daemon (e.g.,
> systemd or any other container manager) to a *trusted* unprivileged
> application. Trust is the key here. This functionality is not about allowing
> unconditional unprivileged BPF usage. Establishing trust, though, is
> completely up to the discretion of respective privileged application that
> would create a BPF token.
>

I skimmed the description and the LSFMM slides.

Years ago, I sent out a patch set to start down the path of making the bpf() API make sense when used in less-privileged contexts (regarding access control of BPF objects and such). It went nowhere.

Where does BPF token fit in? Does a kernel with these patches applied actually behave sensibly if you pass a BPF token into a container? Giving a way to enable BPF in a container is only a small part of the overall task -- making BPF behave sensibly in that container seems like it should also be necessary.