On Thu, 21 Feb 2019 12:56:54 +0100, Toke Høiland-Jørgensen wrote:
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index b63bc77af2d1..629661db36ee 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -7527,6 +7527,12 @@ static int fixup_bpf_calls(struct bpf_verifier_env 
> *env)
>                       prog->dst_needed = 1;
>               if (insn->imm == BPF_FUNC_get_prandom_u32)
>                       bpf_user_rnd_init_once();
> +             if (insn->imm == BPF_FUNC_redirect) {
> +                     int err = dev_map_alloc_default_map();
> +
> +                     if (err)
> +                             return err;
> +             }
>               if (insn->imm == BPF_FUNC_override_return)
>                       prog->kprobe_override = 1;
>               if (insn->imm == BPF_FUNC_tail_call) {

> +int dev_map_alloc_default_map(void)
> +{
> +     struct net *net = current->nsproxy->net_ns;
> +     struct bpf_dtab *dtab, *old_dtab;
> +     struct net_device *netdev;
> +     union bpf_attr attr = {};
> +     u32 idx;
> +     int err;

BPF programs don't obey by netns boundaries.  The fact the program is
verified in one ns doesn't mean this is the only ns it will be used in :(
Meaning if any program is using the redirect map you may need a secret
map in every ns.. no?

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