Messages in this thread | | | Subject | Re: [PATCH v2 net-next 1/3] bpf: enable non-root eBPF programs | From | Alexei Starovoitov <> | Date | Fri, 9 Oct 2015 10:30:49 -0700 |
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On 10/9/15 4:45 AM, Hannes Frederic Sowa wrote: > Afaics this problem hasn't even be solved in > perf so far, tracepoints hit independent of the namespace currently.
yes and that's exactly what we're trying to solve. The "demux+worker bpf programs" proposal is a work-in-progress solution to get confidence how to actually separate tracepoint events into namespaces before adding any new APIs to kernel.
> For me namespacing of ebpf code is actually not that important, I would > much rather like to control which namespace is allowed to execute ebpf > in an unpriviledged manner. Like Thomas wrote, a capability was great > for that, but I don't know if any new capabilities will be added.
I think we're mixing too many things here. First I believe eBPF 'socket filters' do not need any caps. They're packet read-only and functionally very similar to classic with a distinction that packet data can be aggregated into maps and programs can be written in C. So I see no reason to restrict them per user or per namespace. Openstack use case is different. There it will be prog_type_sched_cls that can mangle packets, change skb metadata, etc under TC framework. These are not suitable for all users and this patch leaves them root-only. If you're proposing to add CAP_BPF_TC to let containers use them without being CAP_SYS_ADMIN, then I agree, it is useful, but needs a lot more safety analysis on tc side. Similar for prog_type_kprobe: we can add CAP_BPF_KPROBE to let some trusted applications run unprivileged, but still being able to do performance monitoring/analytics. And we would need to carefully think about program restrictions, since bpf_probe_read and kernel pointer walking is essential part in tracing.
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