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

[Eric Dumazet <eric.dumazet@gmail.com>]

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@nul.nu>
> Signed-off-by: Will Drewry <wad@chromium.org>
> ---
>  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@gmail.com>