On Thu, Jan 23, 2020 at 7:25 AM KP Singh <kpsingh@xxxxxxxxxxxx> wrote:
>
> From: KP Singh <kpsingh@xxxxxxxxxx>
>
> * Add functionality in libbpf to attach eBPF program to LSM hooks
> * Lookup the index of the LSM hook in security_hook_heads and pass it in
> attr->lsm_hook_idx
>
> Signed-off-by: KP Singh <kpsingh@xxxxxxxxxx>
> Reviewed-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
> Reviewed-by: Florent Revest <revest@xxxxxxxxxx>
> Reviewed-by: Thomas Garnier <thgarnie@xxxxxxxxxx>
> ---
Looks good, but see few nits below.
Acked-by: Andrii Nakryiko <andriin@xxxxxx>
> tools/lib/bpf/bpf.c | 6 ++-
> tools/lib/bpf/bpf.h | 1 +
> tools/lib/bpf/libbpf.c | 104 +++++++++++++++++++++++++++++++++++++--
> tools/lib/bpf/libbpf.h | 4 ++
> tools/lib/bpf/libbpf.map | 3 ++
> 5 files changed, 114 insertions(+), 4 deletions(-)
>
[...]
> @@ -5084,6 +5099,8 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
> if (prog->type != BPF_PROG_TYPE_UNSPEC)
> continue;
>
> +
> +
why these extra lines?
> err = libbpf_prog_type_by_name(prog->section_name, &prog_type,
> &attach_type);
> if (err == -ESRCH)
> @@ -6160,6 +6177,7 @@ bool bpf_program__is_##NAME(const struct bpf_program *prog) \
> } \
>
> BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
> +BPF_PROG_TYPE_FNS(lsm, BPF_PROG_TYPE_LSM);
> BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
> BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
> BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
> @@ -6226,6 +6244,8 @@ static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
> struct bpf_program *prog);
> static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
> struct bpf_program *prog);
> +static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
> + struct bpf_program *prog);
>
> struct bpf_sec_def {
> const char *sec;
> @@ -6272,6 +6292,9 @@ static const struct bpf_sec_def section_defs[] = {
> SEC_DEF("freplace/", EXT,
> .is_attach_btf = true,
> .attach_fn = attach_trace),
> + SEC_DEF("lsm/", LSM,
> + .expected_attach_type = BPF_LSM_MAC,
curious, will there be non-MAC LSM programs? if yes, how they are
going to be different and which prefix will we use then?
> + .attach_fn = attach_lsm),
> BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
> BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
> BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
> @@ -6533,6 +6556,44 @@ static int bpf_object__collect_struct_ops_map_reloc(struct bpf_object *obj,
> return -EINVAL;
> }
>
> +static __s32 find_lsm_hook_idx(struct bpf_program *prog)
nit: I'd stick to int for return result, we barely ever use __s32 in libbpf.c
[...]
