selftests/bpf: add kprobe/uprobe selftests

// SPDX-License-Identifier: GPL-2.0

#include <test_progs.h>

ssize_t get_base_addr() {

	size_t start;

	char buf[256];

	FILE *f;

	f = fopen("/proc/self/maps", "r");

	if (!f)

		return -errno;

	while (fscanf(f, "%zx-%*x %s %*s\n", &start, buf) == 2) {

		if (strcmp(buf, "r-xp") == 0) {

			fclose(f);

			return start;

		}

	}

	fclose(f);

	return -EINVAL;

}

#ifdef __x86_64__

#define SYS_KPROBE_NAME "__x64_sys_nanosleep"

#else

#define SYS_KPROBE_NAME "sys_nanosleep"

#endif

void test_attach_probe(void)

{

	const char *kprobe_name = "kprobe/sys_nanosleep";

	const char *kretprobe_name = "kretprobe/sys_nanosleep";

	const char *uprobe_name = "uprobe/trigger_func";

	const char *uretprobe_name = "uretprobe/trigger_func";

	const int kprobe_idx = 0, kretprobe_idx = 1;

	const int uprobe_idx = 2, uretprobe_idx = 3;

	const char *file = "./test_attach_probe.o";

	struct bpf_program *kprobe_prog, *kretprobe_prog;

	struct bpf_program *uprobe_prog, *uretprobe_prog;

	struct bpf_object *obj;

	int err, prog_fd, duration = 0, res;

	struct bpf_link *kprobe_link = NULL;

	struct bpf_link *kretprobe_link = NULL;

	struct bpf_link *uprobe_link = NULL;

	struct bpf_link *uretprobe_link = NULL;

	int results_map_fd;

	size_t uprobe_offset;

	ssize_t base_addr;

	base_addr = get_base_addr();

	if (CHECK(base_addr < 0, "get_base_addr",

		  "failed to find base addr: %zd", base_addr))

		return;

	uprobe_offset = (size_t)&get_base_addr - base_addr;

	/* load programs */

	err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);

	if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))

		return;

	kprobe_prog = bpf_object__find_program_by_title(obj, kprobe_name);

	if (CHECK(!kprobe_prog, "find_probe",

		  "prog '%s' not found\n", kprobe_name))

		goto cleanup;

	kretprobe_prog = bpf_object__find_program_by_title(obj, kretprobe_name);

	if (CHECK(!kretprobe_prog, "find_probe",

		  "prog '%s' not found\n", kretprobe_name))

		goto cleanup;

	uprobe_prog = bpf_object__find_program_by_title(obj, uprobe_name);

	if (CHECK(!uprobe_prog, "find_probe",

		  "prog '%s' not found\n", uprobe_name))

		goto cleanup;

	uretprobe_prog = bpf_object__find_program_by_title(obj, uretprobe_name);

	if (CHECK(!uretprobe_prog, "find_probe",

		  "prog '%s' not found\n", uretprobe_name))

		goto cleanup;

	/* load maps */

	results_map_fd = bpf_find_map(__func__, obj, "results_map");

	if (CHECK(results_map_fd < 0, "find_results_map",

		  "err %d\n", results_map_fd))

		goto cleanup;

	kprobe_link = bpf_program__attach_kprobe(kprobe_prog,

						 false /* retprobe */,

						 SYS_KPROBE_NAME);

	if (CHECK(IS_ERR(kprobe_link), "attach_kprobe",

		  "err %ld\n", PTR_ERR(kprobe_link))) {

		kprobe_link = NULL;

		goto cleanup;

	}

	kretprobe_link = bpf_program__attach_kprobe(kretprobe_prog,

						    true /* retprobe */,

						    SYS_KPROBE_NAME);

	if (CHECK(IS_ERR(kretprobe_link), "attach_kretprobe",

		  "err %ld\n", PTR_ERR(kretprobe_link))) {

		kretprobe_link = NULL;

		goto cleanup;

	}

	uprobe_link = bpf_program__attach_uprobe(uprobe_prog,

						 false /* retprobe */,

						 0 /* self pid */,

						 "/proc/self/exe",

						 uprobe_offset);

	if (CHECK(IS_ERR(uprobe_link), "attach_uprobe",

		  "err %ld\n", PTR_ERR(uprobe_link))) {

		uprobe_link = NULL;

		goto cleanup;

	}

	uretprobe_link = bpf_program__attach_uprobe(uretprobe_prog,

						    true /* retprobe */,

						    -1 /* any pid */,

						    "/proc/self/exe",

						    uprobe_offset);

	if (CHECK(IS_ERR(uretprobe_link), "attach_uretprobe",

		  "err %ld\n", PTR_ERR(uretprobe_link))) {

		uretprobe_link = NULL;

		goto cleanup;

	}

	/* trigger & validate kprobe && kretprobe */

	usleep(1);

	err = bpf_map_lookup_elem(results_map_fd, &kprobe_idx, &res);

	if (CHECK(err, "get_kprobe_res",

		  "failed to get kprobe res: %d\n", err))

		goto cleanup;

	if (CHECK(res != kprobe_idx + 1, "check_kprobe_res",

		  "wrong kprobe res: %d\n", res))

		goto cleanup;

	err = bpf_map_lookup_elem(results_map_fd, &kretprobe_idx, &res);

	if (CHECK(err, "get_kretprobe_res",

		  "failed to get kretprobe res: %d\n", err))

		goto cleanup;

	if (CHECK(res != kretprobe_idx + 1, "check_kretprobe_res",

		  "wrong kretprobe res: %d\n", res))

		goto cleanup;

	/* trigger & validate uprobe & uretprobe */

	get_base_addr();

	err = bpf_map_lookup_elem(results_map_fd, &uprobe_idx, &res);

	if (CHECK(err, "get_uprobe_res",

		  "failed to get uprobe res: %d\n", err))

		goto cleanup;

	if (CHECK(res != uprobe_idx + 1, "check_uprobe_res",

		  "wrong uprobe res: %d\n", res))

		goto cleanup;

	err = bpf_map_lookup_elem(results_map_fd, &uretprobe_idx, &res);

	if (CHECK(err, "get_uretprobe_res",

		  "failed to get uretprobe res: %d\n", err))

		goto cleanup;

	if (CHECK(res != uretprobe_idx + 1, "check_uretprobe_res",

		  "wrong uretprobe res: %d\n", res))

		goto cleanup;

cleanup:

	bpf_link__destroy(kprobe_link);

	bpf_link__destroy(kretprobe_link);

	bpf_link__destroy(uprobe_link);

	bpf_link__destroy(uretprobe_link);

	bpf_object__close(obj);

}

// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2017 Facebook

#include <linux/ptrace.h>

#include <linux/bpf.h>

#include "bpf_helpers.h"

struct {

	int type;

	int max_entries;

	int *key;

	int *value;

} results_map SEC(".maps") = {

	.type = BPF_MAP_TYPE_ARRAY,

	.max_entries = 4,

};

SEC("kprobe/sys_nanosleep")

int handle_sys_nanosleep_entry(struct pt_regs *ctx)

{

	const int key = 0, value = 1;

	bpf_map_update_elem(&results_map, &key, &value, 0);

	return 0;

}

SEC("kretprobe/sys_nanosleep")

int handle_sys_getpid_return(struct pt_regs *ctx)

{

	const int key = 1, value = 2;

	bpf_map_update_elem(&results_map, &key, &value, 0);

	return 0;

}

SEC("uprobe/trigger_func")

int handle_uprobe_entry(struct pt_regs *ctx)

{

	const int key = 2, value = 3;

	bpf_map_update_elem(&results_map, &key, &value, 0);

	return 0;

}

SEC("uretprobe/trigger_func")

int handle_uprobe_return(struct pt_regs *ctx)

{

	const int key = 3, value = 4;

	bpf_map_update_elem(&results_map, &key, &value, 0);

	return 0;

}

char _license[] SEC("license") = "GPL";

__u32 _version SEC("version") = 1;