Re: [PATCH] net: filter: fix upper BPF instruction limit

From: Alexei Starovoitov
Date: Wed Jun 18 2014 - 18:48:11 EST


On Wed, Jun 18, 2014 at 3:34 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> The original checks (via sk_chk_filter) for instruction count uses ">",
> not ">=", so changing this in sk_convert_filter has the potential to break
> existing seccomp filters that used exactly BPF_MAXINSNS many instructions.
>
> Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set")
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # v3.15+

Acked-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>

I wonder how did you catch this? :)
Just code inspection or seccomp actually generating such programs?

Thanks!
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/