Commit 1e092a03 authored by KP Singh's avatar KP Singh Committed by Daniel Borkmann
Browse files

tools/libbpf: Add support for BPF_PROG_TYPE_LSM 



Since BPF_PROG_TYPE_LSM uses the same attaching mechanism as
BPF_PROG_TYPE_TRACING, the common logic is refactored into a static
function bpf_program__attach_btf_id.

A new API call bpf_program__attach_lsm is still added to avoid userspace
conflicts if this ever changes in the future.

Signed-off-by: default avatarKP Singh <kpsingh@google.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: default avatarBrendan Jackman <jackmanb@google.com>
Reviewed-by: default avatarFlorent Revest <revest@google.com>
Reviewed-by: default avatarJames Morris <jamorris@linux.microsoft.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200329004356.27286-7-kpsingh@chromium.org
parent 520b7aa0

tools/lib/bpf/bpf.c

+2 −1
Original line number Diff line number Diff line
@@ -235,7 +235,8 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr, 
	memset(&attr, 0, sizeof(attr));

	attr.prog_type = load_attr->prog_type;

	attr.expected_attach_type = load_attr->expected_attach_type;

	if (attr.prog_type == BPF_PROG_TYPE_STRUCT_OPS) {

	if (attr.prog_type == BPF_PROG_TYPE_STRUCT_OPS ||

	    attr.prog_type == BPF_PROG_TYPE_LSM) {

		attr.attach_btf_id = load_attr->attach_btf_id;

	} else if (attr.prog_type == BPF_PROG_TYPE_TRACING ||

		   attr.prog_type == BPF_PROG_TYPE_EXT) {

tools/lib/bpf/libbpf.c

+35 −4
Original line number Diff line number Diff line
@@ -2358,7 +2358,8 @@ static int bpf_object__finalize_btf(struct bpf_object *obj) 


static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog)

{

	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS)

	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||

	    prog->type == BPF_PROG_TYPE_LSM)

		return true;



	/* BPF_PROG_TYPE_TRACING programs which do not attach to other programs
@@ -4866,7 +4867,8 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, 
	load_attr.insns = insns;

	load_attr.insns_cnt = insns_cnt;

	load_attr.license = license;

	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS) {

	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||

	    prog->type == BPF_PROG_TYPE_LSM) {

		load_attr.attach_btf_id = prog->attach_btf_id;

	} else if (prog->type == BPF_PROG_TYPE_TRACING ||

		   prog->type == BPF_PROG_TYPE_EXT) {
@@ -4957,6 +4959,7 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) 
	int err = 0, fd, i, btf_id;



	if ((prog->type == BPF_PROG_TYPE_TRACING ||

	     prog->type == BPF_PROG_TYPE_LSM ||

	     prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {

		btf_id = libbpf_find_attach_btf_id(prog);

		if (btf_id <= 0)
@@ -6196,6 +6199,7 @@ 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);
@@ -6262,6 +6266,8 @@ 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;
@@ -6312,6 +6318,10 @@ static const struct bpf_sec_def section_defs[] = { 
	SEC_DEF("freplace/", EXT,

		.is_attach_btf = true,

		.attach_fn = attach_trace),

	SEC_DEF("lsm/", LSM,

		.is_attach_btf = true,

		.expected_attach_type = BPF_LSM_MAC,

		.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),
@@ -6574,6 +6584,7 @@ invalid_prog: 
}



#define BTF_TRACE_PREFIX "btf_trace_"

#define BTF_LSM_PREFIX "bpf_lsm_"

#define BTF_MAX_NAME_SIZE 128



static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
@@ -6601,6 +6612,9 @@ static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name, 
	if (attach_type == BPF_TRACE_RAW_TP)

		err = find_btf_by_prefix_kind(btf, BTF_TRACE_PREFIX, name,

					      BTF_KIND_TYPEDEF);

	else if (attach_type == BPF_LSM_MAC)

		err = find_btf_by_prefix_kind(btf, BTF_LSM_PREFIX, name,

					      BTF_KIND_FUNC);

	else

		err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
@@ -7465,7 +7479,8 @@ static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec, 
	return bpf_program__attach_raw_tracepoint(prog, tp_name);

}



struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)

/* Common logic for all BPF program types that attach to a btf_id */

static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog)

{

	char errmsg[STRERR_BUFSIZE];

	struct bpf_link *link;
@@ -7487,7 +7502,7 @@ struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog) 
	if (pfd < 0) {

		pfd = -errno;

		free(link);

		pr_warn("program '%s': failed to attach to trace: %s\n",

		pr_warn("program '%s': failed to attach: %s\n",

			bpf_program__title(prog, false),

			libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));

		return ERR_PTR(pfd);
@@ -7496,12 +7511,28 @@ struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog) 
	return (struct bpf_link *)link;

}



struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)

{

	return bpf_program__attach_btf_id(prog);

}



struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog)

{

	return bpf_program__attach_btf_id(prog);

}



static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,

				     struct bpf_program *prog)

{

	return bpf_program__attach_trace(prog);

}



static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,

				   struct bpf_program *prog)

{

	return bpf_program__attach_lsm(prog);

}



struct bpf_link *bpf_program__attach(struct bpf_program *prog)

{

	const struct bpf_sec_def *sec_def;

tools/lib/bpf/libbpf.h

+4 −0
Original line number Diff line number Diff line
@@ -248,6 +248,8 @@ bpf_program__attach_raw_tracepoint(struct bpf_program *prog, 


LIBBPF_API struct bpf_link *

bpf_program__attach_trace(struct bpf_program *prog);

LIBBPF_API struct bpf_link *

bpf_program__attach_lsm(struct bpf_program *prog);

struct bpf_map;

LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map);

struct bpf_insn;
@@ -321,6 +323,7 @@ LIBBPF_API int bpf_program__set_socket_filter(struct bpf_program *prog); 
LIBBPF_API int bpf_program__set_tracepoint(struct bpf_program *prog);

LIBBPF_API int bpf_program__set_raw_tracepoint(struct bpf_program *prog);

LIBBPF_API int bpf_program__set_kprobe(struct bpf_program *prog);

LIBBPF_API int bpf_program__set_lsm(struct bpf_program *prog);

LIBBPF_API int bpf_program__set_sched_cls(struct bpf_program *prog);

LIBBPF_API int bpf_program__set_sched_act(struct bpf_program *prog);

LIBBPF_API int bpf_program__set_xdp(struct bpf_program *prog);
@@ -347,6 +350,7 @@ LIBBPF_API bool bpf_program__is_socket_filter(const struct bpf_program *prog); 
LIBBPF_API bool bpf_program__is_tracepoint(const struct bpf_program *prog);

LIBBPF_API bool bpf_program__is_raw_tracepoint(const struct bpf_program *prog);

LIBBPF_API bool bpf_program__is_kprobe(const struct bpf_program *prog);

LIBBPF_API bool bpf_program__is_lsm(const struct bpf_program *prog);

LIBBPF_API bool bpf_program__is_sched_cls(const struct bpf_program *prog);

LIBBPF_API bool bpf_program__is_sched_act(const struct bpf_program *prog);

LIBBPF_API bool bpf_program__is_xdp(const struct bpf_program *prog);

tools/lib/bpf/libbpf.map

+3 −0
Original line number Diff line number Diff line
@@ -244,6 +244,9 @@ LIBBPF_0.0.8 { 
		bpf_link__pin_path;

		bpf_link__unpin;

		bpf_map__set_initial_value;

		bpf_program__attach_lsm;

		bpf_program__is_lsm;

		bpf_program__set_attach_target;

		bpf_program__set_lsm;

		bpf_set_link_xdp_fd_opts;

} LIBBPF_0.0.7;

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