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>

diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
new file mode 100644 (file)
index 0000000..a468639
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
@@ -0,0 +1,166 @@
+// 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);
+}

diff --git a/tools/testing/selftests/bpf/progs/test_attach_probe.c b/tools/testing/selftests/bpf/progs/test_attach_probe.c
new file mode 100644 (file)
index 0000000..7a7c5cd
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_attach_probe.c
@@ -0,0 +1,55 @@
+// 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;