Re: [PATCH bpf 1/2] flow_dissector: reject invalid attach_flags

[Alexei Starovoitov]

On Fri, Jun 12, 2020 at 9:02 AM Lorenz Bauer <lmb@xxxxxxxxxxxxxx> wrote:
>
> Using BPF_PROG_ATTACH on a flow dissector program supports neither flags
> nor target_fd but accepts any value. Return EINVAL if either are non-zero.
>
> Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
> Fixes: b27f7bb590ba ("flow_dissector: Move out netns_bpf prog callbacks")
> ---
>  kernel/bpf/net_namespace.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c
> index 78cf061f8179..56133e78ae4f 100644
> --- a/kernel/bpf/net_namespace.c
> +++ b/kernel/bpf/net_namespace.c
> @@ -192,6 +192,9 @@ int netns_bpf_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
>         struct net *net;
>         int ret;
>
> +       if (attr->attach_flags || attr->target_fd)
> +               return -EINVAL;
> +

In theory it makes sense, but how did you test it?
test_progs -t flow
fails 5 tests.