[PATCH v2 security-next 1/4] security: Hornet LSM

[Paul Moore]

On Tue, Apr 15, 2025 at 3:08 PM Blaise Boscaccy
<bboscaccy at linux.microsoft.com> wrote:
> ... would you be ammenable to a simple patch in
> skel_internal.h that freezes maps? e.g

I have limited network access at the moment, so it is possible I've
missed it, but I think it would be helpful to get a verdict on the
RFC-esque patch from Blaise below.

> diff --git a/tools/lib/bpf/skel_internal.h b/tools/lib/bpf/skel_internal.h
> index 4d5fa079b5d6..51e72dc23062 100644
> --- a/tools/lib/bpf/skel_internal.h
> +++ b/tools/lib/bpf/skel_internal.h
> @@ -263,6 +263,17 @@ static inline int skel_map_delete_elem(int fd, const void *key)
>         return skel_sys_bpf(BPF_MAP_DELETE_ELEM, &attr, attr_sz);
>  }
>
> +static inline int skel_map_freeze(int fd)
> +{
> +       const size_t attr_sz = offsetofend(union bpf_attr, map_fd);
> +       union bpf_attr attr;
> +
> +       memset(&attr, 0, attr_sz);
> +       attr.map_fd = fd;
> +
> +       return skel_sys_bpf(BPF_MAP_FREEZE, &attr, attr_sz);
> +}
> +
>  static inline int skel_map_get_fd_by_id(__u32 id)
>  {
>         const size_t attr_sz = offsetofend(union bpf_attr, flags);
> @@ -327,6 +338,13 @@ static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
>                 goto out;
>         }
>
> +       err = skel_map_freeze(map_fd);
> +       if (err < 0) {
> +               opts->errstr = "failed to freeze map";
> +               set_err;
> +               goto out;
> +       }
> +
>         memset(&attr, 0, prog_load_attr_sz);
>         attr.prog_type = BPF_PROG_TYPE_SYSCALL;
>         attr.insns = (long) opts->insns;
>

-- 
paul-moore.com