[net-next v3 1/2] bpf, seccomp: Add eBPF filter capabilities

[Tycho Andersen]

On Mon, Feb 26, 2018 at 07:49:48PM -0800, Sargun Dhillon wrote:
> On Mon, Feb 26, 2018 at 4:54 PM, Tycho Andersen <tycho at tycho.ws> wrote:
> > On Mon, Feb 26, 2018 at 07:27:05AM +0000, Sargun Dhillon wrote:
> >> +config SECCOMP_FILTER_EXTENDED
> >> +     bool "Extended BPF seccomp filters"
> >> +     depends on SECCOMP_FILTER && BPF_SYSCALL
> >> +     depends on !CHECKPOINT_RESTORE
> >
> > Why not just give -EINVAL or something in case one of these is
> > requested, instead of making them incompatible at compile time?
> >
> > Tycho
> There's already code to return -EMEDIUMTYPE if it's a non-classic, or
> non-saved filter. Under the normal case, with CHECKPOINT_RESTORE
> enabled, you should never be able to get that. I think it makes sense
> to preserve this behaviour.

Oh, right. So can't we just drop this, and the existing code will
DTRT, i.e. give you -EMEDIUMTYPE because the new filters aren't
supported, until they are?

Tycho