Re: [PATCH v15 01/13] sk_run_filter: add BPF_S_ANC_SECCOMP_LD_W

From: Eric Dumazet
Date: Fri Mar 16 2012 - 14:15:44 EST


On Wed, 2012-03-14 at 22:11 -0500, Will Drewry wrote:
> Introduces a new BPF ancillary instruction that all LD calls will be
> mapped through when skb_run_filter() is being used for seccomp BPF. The
> rewriting will be done using a secondary chk_filter function that is run
> after skb_chk_filter.
>
> The code change is guarded by CONFIG_SECCOMP_FILTER which is added,
> along with the seccomp_bpf_load() function later in this series.
>
> This is based on http://lkml.org/lkml/2012/3/2/141
>
> v15: include seccomp.h explicitly for when seccomp_bpf_load exists.
> v14: First cut using a single additional instruction
> ... v13: made bpf functions generic.
>
> Suggested-by: Indan Zupancic <indan@xxxxxx>
> Signed-off-by: Will Drewry <wad@xxxxxxxxxxxx>
> ---
> include/linux/filter.h | 1 +
> net/core/filter.c | 6 ++++++
> 2 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/filter.h b/include/linux/filter.h
> index 8eeb205..aaa2e80 100644
> --- a/include/linux/filter.h
> +++ b/include/linux/filter.h
> @@ -228,6 +228,7 @@ enum {
> BPF_S_ANC_HATYPE,
> BPF_S_ANC_RXHASH,
> BPF_S_ANC_CPU,
> + BPF_S_ANC_SECCOMP_LD_W,
> };
>
> #endif /* __KERNEL__ */
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 5dea452..d775edc 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -39,6 +39,7 @@
> #include <linux/filter.h>
> #include <linux/reciprocal_div.h>
> #include <linux/ratelimit.h>
> +#include <linux/seccomp.h>
>
> /* No hurry in this branch */
> static void *__load_pointer(const struct sk_buff *skb, int k, unsigned int size)
> @@ -350,6 +351,11 @@ load_b:
> A = 0;
> continue;
> }
> +#ifdef CONFIG_SECCOMP_FILTER
> + case BPF_S_ANC_SECCOMP_LD_W:
> + A = seccomp_bpf_load(fentry->k);
> + continue;
> +#endif
> default:
> WARN_RATELIMIT(1, "Unknown code:%u jt:%u tf:%u k:%u\n",
> fentry->code, fentry->jt,


Acked-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>


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