selftests/bpf: add kprobe/uprobe selftests

Add tests verifying kprobe/kretprobe/uprobe/uretprobe APIs work as
expected.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Andrii Nakryiko 2019-07-01 16:59:02 -07:00 committed by Daniel Borkmann
parent 8c51b314d2
commit 1e8611bbdf
2 changed files with 221 additions and 0 deletions

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// 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);
}

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// 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;