On Wed, 27 Jul 2022 17:45:46 -0700 Martin KaFai Lau wrote:
> > bool setsockopt_capable(struct user_namespace *ns, int cap)
> > {
> > if (!in_task()) {
> > /* Running in irq/softirq -> setsockopt invoked by bpf program.
> > * [not sure, is it safe to assume no regular path leads
> > to setsockopt from sirq?]
> > */
> > return true;
> > }
> >
> > /* Running in process context, task has bpf_ctx set -> invoked
> > by bpf program. */
> > if (current->bpf_ctx != NULL)
> > return true;
> >
> > return ns_capable(ns, cap);
> > }
> >
> > And then do /ns_capable/setsockopt_capable/ in net/core/sock.c
> >
> > But that might be more fragile than passing the flag, idk.
> I think it should work. From a quick look, all bpf_setsockopt usage has
> bpf_ctx. The one from bpf_tcp_ca (struct_ops) and bpf_iter is trampoline
> which also has bpf_ctx. Not sure about the future use cases.
>
> To be honest, I am not sure if I have missed cases and also have similar questions
> your have in the above sample code. This may deserve a separate patch
> set for discussion. Using a bit in sockptr is mostly free now.
> WDYT ?
Sorry to chime in but I vote against @in_bpf. I had to search the git
history recently to figure out what SK_USER_DATA_BPF means. It's not
going to be obvious to a networking person what semantics to attribute
to "in bpf".
