diff mbox series

[bpf-next,v4,6/8] tools/libbpf: Add support for BPF_PROG_TYPE_LSM

Message ID 20200220175250.10795-7-kpsingh@chromium.org
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series MAC and Audit policy using eBPF (KRSI) | expand

Commit Message

KP Singh Feb. 20, 2020, 5:52 p.m. UTC 
From: KP Singh <kpsingh@google.com>

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.

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: KP Singh <kpsingh@google.com>
---
 tools/lib/bpf/bpf.c      |  3 ++-
 tools/lib/bpf/libbpf.c   | 46 ++++++++++++++++++++++++++++++++--------
 tools/lib/bpf/libbpf.h   |  4 ++++
 tools/lib/bpf/libbpf.map |  3 +++
 4 files changed, 46 insertions(+), 10 deletions(-)

Comments

Andrii Nakryiko Feb. 25, 2020, 6:45 a.m. UTC | #1 
On Thu, Feb 20, 2020 at 9:53 AM KP Singh <kpsingh@chromium.org> wrote:
>
> From: KP Singh <kpsingh@google.com>
>
> 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.
>
> 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: KP Singh <kpsingh@google.com>
> ---
>  tools/lib/bpf/bpf.c      |  3 ++-
>  tools/lib/bpf/libbpf.c   | 46 ++++++++++++++++++++++++++++++++--------
>  tools/lib/bpf/libbpf.h   |  4 ++++
>  tools/lib/bpf/libbpf.map |  3 +++
>  4 files changed, 46 insertions(+), 10 deletions(-)
>
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index c6dafe563176..73220176728d 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -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) {
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 514b1a524abb..d11139d5e76b 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -2351,16 +2351,14 @@ 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
>          * also need vmlinux BTF
>          */
> -       if (prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd)
> -               return true;
> -
> -       return false;
> +       return prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd;


please keep this as is, it allows to add more logic easily, if necessary

>  }
>
>  static int bpf_object__load_vmlinux_btf(struct bpf_object *obj)
> @@ -4855,7 +4853,8 @@ 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;

[...]

> -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(struct bpf_program *prog)
>  {
>         char errmsg[STRERR_BUFSIZE];
>         struct bpf_link_fd *link;
> @@ -7376,7 +7388,7 @@ 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 to: %s\n",

to attach to ... what?.. %s at the end is just an error message

>                         bpf_program__title(prog, false),
>                         libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
>                 return ERR_PTR(pfd);
> @@ -7385,10 +7397,26 @@ struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
>         return (struct bpf_link *)link;
>  }
>

[...]

> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -227,10 +227,13 @@ LIBBPF_0.0.7 {
>                 bpf_probe_large_insn_limit;
>                 bpf_prog_attach_xattr;
>                 bpf_program__attach;
> +               bpf_program__attach_lsm;
>                 bpf_program__name;
>                 bpf_program__is_extension;
> +               bpf_program__is_lsm;
>                 bpf_program__is_struct_ops;
>                 bpf_program__set_extension;
> +               bpf_program__set_lsm;

please make sure to add to 0.0.8 version for new revision

>                 bpf_program__set_struct_ops;
>                 btf__align_of;
>                 libbpf_find_kernel_btf;
> --
> 2.20.1
>
diff mbox series

Patch

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index c6dafe563176..73220176728d 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -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) {
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 514b1a524abb..d11139d5e76b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2351,16 +2351,14 @@  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
 	 * also need vmlinux BTF
 	 */
-	if (prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd)
-		return true;
-
-	return false;
+	return prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd;
 }
 
 static int bpf_object__load_vmlinux_btf(struct bpf_object *obj)
@@ -4855,7 +4853,8 @@  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) {
@@ -4940,6 +4939,7 @@  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) {
 		btf_id = libbpf_find_attach_btf_id(prog);
 		if (btf_id <= 0)
@@ -6179,6 +6179,7 @@  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);
@@ -6245,6 +6246,8 @@  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;
@@ -6291,6 +6294,10 @@  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),
@@ -6553,6 +6560,7 @@  static int bpf_object__collect_struct_ops_map_reloc(struct bpf_object *obj,
 }
 
 #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,
@@ -6580,6 +6588,9 @@  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);
 
@@ -7354,7 +7365,8 @@  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(struct bpf_program *prog)
 {
 	char errmsg[STRERR_BUFSIZE];
 	struct bpf_link_fd *link;
@@ -7376,7 +7388,7 @@  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 to: %s\n",
 			bpf_program__title(prog, false),
 			libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
 		return ERR_PTR(pfd);
@@ -7385,10 +7397,26 @@  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(prog);
+}
+
+struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog)
+{
+	return bpf_program__attach_btf(prog);
+}
+
 static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
 				     struct bpf_program *prog)
 {
-	return bpf_program__attach_trace(prog);
+	return bpf_program__attach_btf(prog);
+}
+
+static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
+				   struct bpf_program *prog)
+{
+	return bpf_program__attach_btf(prog);
 }
 
 struct bpf_link *bpf_program__attach(struct bpf_program *prog)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 3fe12c9d1f92..3f72323f205b 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -243,6 +243,8 @@  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;
@@ -316,6 +318,7 @@  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);
@@ -338,6 +341,7 @@  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);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index b035122142bb..8df332a528a0 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -227,10 +227,13 @@  LIBBPF_0.0.7 {
 		bpf_probe_large_insn_limit;
 		bpf_prog_attach_xattr;
 		bpf_program__attach;
+		bpf_program__attach_lsm;
 		bpf_program__name;
 		bpf_program__is_extension;
+		bpf_program__is_lsm;
 		bpf_program__is_struct_ops;
 		bpf_program__set_extension;
+		bpf_program__set_lsm;
 		bpf_program__set_struct_ops;
 		btf__align_of;
 		libbpf_find_kernel_btf;