selftests/bpf: Add selftest for fill_link_info

Add selftest for the fill_link_info of uprobe, kprobe and tracepoint.
The result:

  $ tools/testing/selftests/bpf/test_progs --name=fill_link_info
  #79/1    fill_link_info/kprobe_link_info:OK
  #79/2    fill_link_info/kretprobe_link_info:OK
  #79/3    fill_link_info/kprobe_invalid_ubuff:OK
  #79/4    fill_link_info/tracepoint_link_info:OK
  #79/5    fill_link_info/uprobe_link_info:OK
  #79/6    fill_link_info/uretprobe_link_info:OK
  #79/7    fill_link_info/kprobe_multi_link_info:OK
  #79/8    fill_link_info/kretprobe_multi_link_info:OK
  #79/9    fill_link_info/kprobe_multi_invalid_ubuff:OK
  #79      fill_link_info:OK
  Summary: 1/9 PASSED, 0 SKIPPED, 0 FAILED

The test case for kprobe_multi won't be run on aarch64, as it is not
supported.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230813141900.1268-3-laoar.shao@gmail.com

diff --git a/tools/testing/selftests/bpf/DENYLIST.aarch64 b/tools/testing/selftests/bpf/DENYLIST.aarch64
index 3b61e8b35d6203ad8cc6389ea857e394263d3dde..7f768d335698764527bb997413bcf63beef35991 100644 (file)
--- a/tools/testing/selftests/bpf/DENYLIST.aarch64
+++ b/tools/testing/selftests/bpf/DENYLIST.aarch64
@@ -12,3 +12,6 @@ kprobe_multi_test/skel_api                       # libbpf: failed to load BPF sk
 module_attach                                    # prog 'kprobe_multi': failed to auto-attach: -95
 fentry_test/fentry_many_args                     # fentry_many_args:FAIL:fentry_many_args_attach unexpected error: -524
 fexit_test/fexit_many_args                       # fexit_many_args:FAIL:fexit_many_args_attach unexpected error: -524
+fill_link_info/kprobe_multi_link_info            # bpf_program__attach_kprobe_multi_opts unexpected error: -95
+fill_link_info/kretprobe_multi_link_info         # bpf_program__attach_kprobe_multi_opts unexpected error: -95
+fill_link_info/kprobe_multi_invalid_ubuff        # bpf_program__attach_kprobe_multi_opts unexpected error: -95

diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
new file mode 100644 (file)
index 0000000..9d768e0
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -0,0 +1,342 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */
+
+#include <string.h>
+#include <linux/bpf.h>
+#include <linux/limits.h>
+#include <test_progs.h>
+#include "trace_helpers.h"
+#include "test_fill_link_info.skel.h"
+
+#define TP_CAT "sched"
+#define TP_NAME "sched_switch"
+
+static const char *kmulti_syms[] = {
+       "bpf_fentry_test2",
+       "bpf_fentry_test1",
+       "bpf_fentry_test3",
+};
+#define KMULTI_CNT ARRAY_SIZE(kmulti_syms)
+static __u64 kmulti_addrs[KMULTI_CNT];
+
+#define KPROBE_FUNC "bpf_fentry_test1"
+static __u64 kprobe_addr;
+
+#define UPROBE_FILE "/proc/self/exe"
+static ssize_t uprobe_offset;
+/* uprobe attach point */
+static noinline void uprobe_func(void)
+{
+       asm volatile ("");
+}
+
+static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long addr,
+                                ssize_t offset, ssize_t entry_offset)
+{
+       struct bpf_link_info info;
+       __u32 len = sizeof(info);
+       char buf[PATH_MAX];
+       int err;
+
+       memset(&info, 0, sizeof(info));
+       buf[0] = '\0';
+
+again:
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       if (!ASSERT_OK(err, "get_link_info"))
+               return -1;
+
+       if (!ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "link_type"))
+               return -1;
+       if (!ASSERT_EQ(info.perf_event.type, type, "perf_type_match"))
+               return -1;
+
+       switch (info.perf_event.type) {
+       case BPF_PERF_EVENT_KPROBE:
+       case BPF_PERF_EVENT_KRETPROBE:
+               ASSERT_EQ(info.perf_event.kprobe.offset, offset, "kprobe_offset");
+
+               /* In case kernel.kptr_restrict is not permitted or MAX_SYMS is reached */
+               if (addr)
+                       ASSERT_EQ(info.perf_event.kprobe.addr, addr + entry_offset,
+                                 "kprobe_addr");
+
+               if (!info.perf_event.kprobe.func_name) {
+                       ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
+                       info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
+                       info.perf_event.kprobe.name_len = sizeof(buf);
+                       goto again;
+               }
+
+               err = strncmp(u64_to_ptr(info.perf_event.kprobe.func_name), KPROBE_FUNC,
+                             strlen(KPROBE_FUNC));
+               ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
+               break;
+       case BPF_PERF_EVENT_TRACEPOINT:
+               if (!info.perf_event.tracepoint.tp_name) {
+                       ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
+                       info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
+                       info.perf_event.tracepoint.name_len = sizeof(buf);
+                       goto again;
+               }
+
+               err = strncmp(u64_to_ptr(info.perf_event.tracepoint.tp_name), TP_NAME,
+                             strlen(TP_NAME));
+               ASSERT_EQ(err, 0, "cmp_tp_name");
+               break;
+       case BPF_PERF_EVENT_UPROBE:
+       case BPF_PERF_EVENT_URETPROBE:
+               ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+
+               if (!info.perf_event.uprobe.file_name) {
+                       ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
+                       info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
+                       info.perf_event.uprobe.name_len = sizeof(buf);
+                       goto again;
+               }
+
+               err = strncmp(u64_to_ptr(info.perf_event.uprobe.file_name), UPROBE_FILE,
+                             strlen(UPROBE_FILE));
+                       ASSERT_EQ(err, 0, "cmp_file_name");
+               break;
+       default:
+               err = -1;
+               break;
+       }
+       return err;
+}
+
+static void kprobe_fill_invalid_user_buffer(int fd)
+{
+       struct bpf_link_info info;
+       __u32 len = sizeof(info);
+       int err;
+
+       memset(&info, 0, sizeof(info));
+
+       info.perf_event.kprobe.func_name = 0x1; /* invalid address */
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -EINVAL, "invalid_buff_and_len");
+
+       info.perf_event.kprobe.name_len = 64;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -EFAULT, "invalid_buff");
+
+       info.perf_event.kprobe.func_name = 0;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -EINVAL, "invalid_len");
+
+       ASSERT_EQ(info.perf_event.kprobe.addr, 0, "func_addr");
+       ASSERT_EQ(info.perf_event.kprobe.offset, 0, "func_offset");
+       ASSERT_EQ(info.perf_event.type, 0, "type");
+}
+
+static void test_kprobe_fill_link_info(struct test_fill_link_info *skel,
+                                      enum bpf_perf_event_type type,
+                                      bool invalid)
+{
+       DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts,
+               .attach_mode = PROBE_ATTACH_MODE_LINK,
+               .retprobe = type == BPF_PERF_EVENT_KRETPROBE,
+       );
+       ssize_t entry_offset = 0;
+       int link_fd, err;
+
+       skel->links.kprobe_run = bpf_program__attach_kprobe_opts(skel->progs.kprobe_run,
+                                                                KPROBE_FUNC, &opts);
+       if (!ASSERT_OK_PTR(skel->links.kprobe_run, "attach_kprobe"))
+               return;
+
+       link_fd = bpf_link__fd(skel->links.kprobe_run);
+       if (!invalid) {
+               /* See also arch_adjust_kprobe_addr(). */
+               if (skel->kconfig->CONFIG_X86_KERNEL_IBT)
+                       entry_offset = 4;
+               err = verify_perf_link_info(link_fd, type, kprobe_addr, 0, entry_offset);
+               ASSERT_OK(err, "verify_perf_link_info");
+       } else {
+               kprobe_fill_invalid_user_buffer(link_fd);
+       }
+       bpf_link__detach(skel->links.kprobe_run);
+}
+
+static void test_tp_fill_link_info(struct test_fill_link_info *skel)
+{
+       int link_fd, err;
+
+       skel->links.tp_run = bpf_program__attach_tracepoint(skel->progs.tp_run, TP_CAT, TP_NAME);
+       if (!ASSERT_OK_PTR(skel->links.tp_run, "attach_tp"))
+               return;
+
+       link_fd = bpf_link__fd(skel->links.tp_run);
+       err = verify_perf_link_info(link_fd, BPF_PERF_EVENT_TRACEPOINT, 0, 0, 0);
+       ASSERT_OK(err, "verify_perf_link_info");
+       bpf_link__detach(skel->links.tp_run);
+}
+
+static void test_uprobe_fill_link_info(struct test_fill_link_info *skel,
+                                      enum bpf_perf_event_type type)
+{
+       int link_fd, err;
+
+       skel->links.uprobe_run = bpf_program__attach_uprobe(skel->progs.uprobe_run,
+                                                           type == BPF_PERF_EVENT_URETPROBE,
+                                                           0, /* self pid */
+                                                           UPROBE_FILE, uprobe_offset);
+       if (!ASSERT_OK_PTR(skel->links.uprobe_run, "attach_uprobe"))
+               return;
+
+       link_fd = bpf_link__fd(skel->links.uprobe_run);
+       err = verify_perf_link_info(link_fd, type, 0, uprobe_offset, 0);
+       ASSERT_OK(err, "verify_perf_link_info");
+       bpf_link__detach(skel->links.uprobe_run);
+}
+
+static int verify_kmulti_link_info(int fd, bool retprobe)
+{
+       struct bpf_link_info info;
+       __u32 len = sizeof(info);
+       __u64 addrs[KMULTI_CNT];
+       int flags, i, err;
+
+       memset(&info, 0, sizeof(info));
+
+again:
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       if (!ASSERT_OK(err, "get_link_info"))
+               return -1;
+
+       if (!ASSERT_EQ(info.type, BPF_LINK_TYPE_KPROBE_MULTI, "kmulti_type"))
+               return -1;
+
+       ASSERT_EQ(info.kprobe_multi.count, KMULTI_CNT, "func_cnt");
+       flags = info.kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN;
+       if (!retprobe)
+               ASSERT_EQ(flags, 0, "kmulti_flags");
+       else
+               ASSERT_NEQ(flags, 0, "kretmulti_flags");
+
+       if (!info.kprobe_multi.addrs) {
+               info.kprobe_multi.addrs = ptr_to_u64(addrs);
+               goto again;
+       }
+       for (i = 0; i < KMULTI_CNT; i++)
+               ASSERT_EQ(addrs[i], kmulti_addrs[i], "kmulti_addrs");
+       return 0;
+}
+
+static void verify_kmulti_invalid_user_buffer(int fd)
+{
+       struct bpf_link_info info;
+       __u32 len = sizeof(info);
+       __u64 addrs[KMULTI_CNT];
+       int err, i;
+
+       memset(&info, 0, sizeof(info));
+
+       info.kprobe_multi.count = KMULTI_CNT;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -EINVAL, "no_addr");
+
+       info.kprobe_multi.addrs = ptr_to_u64(addrs);
+       info.kprobe_multi.count = 0;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -EINVAL, "no_cnt");
+
+       for (i = 0; i < KMULTI_CNT; i++)
+               addrs[i] = 0;
+       info.kprobe_multi.count = KMULTI_CNT - 1;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -ENOSPC, "smaller_cnt");
+       for (i = 0; i < KMULTI_CNT - 1; i++)
+               ASSERT_EQ(addrs[i], kmulti_addrs[i], "kmulti_addrs");
+       ASSERT_EQ(addrs[i], 0, "kmulti_addrs");
+
+       for (i = 0; i < KMULTI_CNT; i++)
+               addrs[i] = 0;
+       info.kprobe_multi.count = KMULTI_CNT + 1;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, 0, "bigger_cnt");
+       for (i = 0; i < KMULTI_CNT; i++)
+               ASSERT_EQ(addrs[i], kmulti_addrs[i], "kmulti_addrs");
+
+       info.kprobe_multi.count = KMULTI_CNT;
+       info.kprobe_multi.addrs = 0x1; /* invalid addr */
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -EFAULT, "invalid_buff");
+}
+
+static int symbols_cmp_r(const void *a, const void *b)
+{
+       const char **str_a = (const char **) a;
+       const char **str_b = (const char **) b;
+
+       return strcmp(*str_a, *str_b);
+}
+
+static void test_kprobe_multi_fill_link_info(struct test_fill_link_info *skel,
+                                            bool retprobe, bool invalid)
+{
+       LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+       int link_fd, err;
+
+       opts.syms = kmulti_syms;
+       opts.cnt = KMULTI_CNT;
+       opts.retprobe = retprobe;
+       skel->links.kmulti_run = bpf_program__attach_kprobe_multi_opts(skel->progs.kmulti_run,
+                                                                      NULL, &opts);
+       if (!ASSERT_OK_PTR(skel->links.kmulti_run, "attach_kprobe_multi"))
+               return;
+
+       link_fd = bpf_link__fd(skel->links.kmulti_run);
+       if (!invalid) {
+               err = verify_kmulti_link_info(link_fd, retprobe);
+               ASSERT_OK(err, "verify_kmulti_link_info");
+       } else {
+               verify_kmulti_invalid_user_buffer(link_fd);
+       }
+       bpf_link__detach(skel->links.kmulti_run);
+}
+
+void test_fill_link_info(void)
+{
+       struct test_fill_link_info *skel;
+       int i;
+
+       skel = test_fill_link_info__open_and_load();
+       if (!ASSERT_OK_PTR(skel, "skel_open"))
+               return;
+
+       /* load kallsyms to compare the addr */
+       if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh"))
+               goto cleanup;
+
+       kprobe_addr = ksym_get_addr(KPROBE_FUNC);
+       if (test__start_subtest("kprobe_link_info"))
+               test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false);
+       if (test__start_subtest("kretprobe_link_info"))
+               test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KRETPROBE, false);
+       if (test__start_subtest("kprobe_invalid_ubuff"))
+               test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, true);
+       if (test__start_subtest("tracepoint_link_info"))
+               test_tp_fill_link_info(skel);
+
+       uprobe_offset = get_uprobe_offset(&uprobe_func);
+       if (test__start_subtest("uprobe_link_info"))
+               test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_UPROBE);
+       if (test__start_subtest("uretprobe_link_info"))
+               test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_URETPROBE);
+
+       qsort(kmulti_syms, KMULTI_CNT, sizeof(kmulti_syms[0]), symbols_cmp_r);
+       for (i = 0; i < KMULTI_CNT; i++)
+               kmulti_addrs[i] = ksym_get_addr(kmulti_syms[i]);
+       if (test__start_subtest("kprobe_multi_link_info"))
+               test_kprobe_multi_fill_link_info(skel, false, false);
+       if (test__start_subtest("kretprobe_multi_link_info"))
+               test_kprobe_multi_fill_link_info(skel, true, false);
+       if (test__start_subtest("kprobe_multi_invalid_ubuff"))
+               test_kprobe_multi_fill_link_info(skel, true, true);
+
+cleanup:
+       test_fill_link_info__destroy(skel);
+}

diff --git a/tools/testing/selftests/bpf/progs/test_fill_link_info.c b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
new file mode 100644 (file)
index 0000000..564f402
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */
+
+#include "vmlinux.h"
+#include <bpf/bpf_tracing.h>
+#include <stdbool.h>
+
+extern bool CONFIG_X86_KERNEL_IBT __kconfig __weak;
+
+/* This function is here to have CONFIG_X86_KERNEL_IBT
+ * used and added to object BTF.
+ */
+int unused(void)
+{
+       return CONFIG_X86_KERNEL_IBT ? 0 : 1;
+}
+
+SEC("kprobe")
+int BPF_PROG(kprobe_run)
+{
+       return 0;
+}
+
+SEC("uprobe")
+int BPF_PROG(uprobe_run)
+{
+       return 0;
+}
+
+SEC("tracepoint")
+int BPF_PROG(tp_run)
+{
+       return 0;
+}
+
+SEC("kprobe.multi")
+int BPF_PROG(kmulti_run)
+{
+       return 0;
+}
+
+char _license[] SEC("license") = "GPL";