Re: [PATCH bpf-next] bpf, capabilities: introduce CAP_BPF

On Thu, 29 Aug 2019 10:23:10 -0700
Alexei Starovoitov [off-list ref] wrote:

quoted

CAP_TRACE_KERNEL: Use all of perf, ftrace, kprobe, etc.

CAP_TRACE_USER: Use all of perf with scope limited to user mode and uprobes.  

imo that makes little sense from security pov, since
such CAP_TRACE_KERNEL (ex kprobe) can trace "unrelated user process"
just as well. Yet not letting it do cleanly via uprobe.
Sort of like giving a spare key for back door of the house and
saying no, you cannot have main door key.

I took it as CAP_TRACE_KERNEL as a superset of CAP_TRACE_USER. That is,
if you have CAP_TRACE_KERNEL, by default you get USER. Where as
CAP_TRACE_USER, is much more limiting.

-- Steve