1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */
3
4 #include <string.h>
5 #include <linux/bpf.h>
6 #include <linux/limits.h>
7 #include <test_progs.h>
8 #include "trace_helpers.h"
9 #include "test_fill_link_info.skel.h"
10
11 #define TP_CAT "sched"
12 #define TP_NAME "sched_switch"
13
14 static const char *kmulti_syms[] = {
15 "bpf_fentry_test2",
16 "bpf_fentry_test1",
17 "bpf_fentry_test3",
18 };
19 #define KMULTI_CNT ARRAY_SIZE(kmulti_syms)
20 static __u64 kmulti_addrs[KMULTI_CNT];
21
22 #define KPROBE_FUNC "bpf_fentry_test1"
23 static __u64 kprobe_addr;
24
25 #define UPROBE_FILE "/proc/self/exe"
26 static ssize_t uprobe_offset;
27 /* uprobe attach point */
uprobe_func(void)28 static noinline void uprobe_func(void)
29 {
30 asm volatile ("");
31 }
32
verify_perf_link_info(int fd,enum bpf_perf_event_type type,long addr,ssize_t offset,ssize_t entry_offset)33 static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long addr,
34 ssize_t offset, ssize_t entry_offset)
35 {
36 struct bpf_link_info info;
37 __u32 len = sizeof(info);
38 char buf[PATH_MAX];
39 int err;
40
41 memset(&info, 0, sizeof(info));
42 buf[0] = '\0';
43
44 again:
45 err = bpf_link_get_info_by_fd(fd, &info, &len);
46 if (!ASSERT_OK(err, "get_link_info"))
47 return -1;
48
49 if (!ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "link_type"))
50 return -1;
51 if (!ASSERT_EQ(info.perf_event.type, type, "perf_type_match"))
52 return -1;
53
54 switch (info.perf_event.type) {
55 case BPF_PERF_EVENT_KPROBE:
56 case BPF_PERF_EVENT_KRETPROBE:
57 ASSERT_EQ(info.perf_event.kprobe.offset, offset, "kprobe_offset");
58
59 /* In case kernel.kptr_restrict is not permitted or MAX_SYMS is reached */
60 if (addr)
61 ASSERT_EQ(info.perf_event.kprobe.addr, addr + entry_offset,
62 "kprobe_addr");
63
64 if (!info.perf_event.kprobe.func_name) {
65 ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
66 info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
67 info.perf_event.kprobe.name_len = sizeof(buf);
68 goto again;
69 }
70
71 err = strncmp(u64_to_ptr(info.perf_event.kprobe.func_name), KPROBE_FUNC,
72 strlen(KPROBE_FUNC));
73 ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
74 break;
75 case BPF_PERF_EVENT_TRACEPOINT:
76 if (!info.perf_event.tracepoint.tp_name) {
77 ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
78 info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
79 info.perf_event.tracepoint.name_len = sizeof(buf);
80 goto again;
81 }
82
83 err = strncmp(u64_to_ptr(info.perf_event.tracepoint.tp_name), TP_NAME,
84 strlen(TP_NAME));
85 ASSERT_EQ(err, 0, "cmp_tp_name");
86 break;
87 case BPF_PERF_EVENT_UPROBE:
88 case BPF_PERF_EVENT_URETPROBE:
89 ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
90
91 if (!info.perf_event.uprobe.file_name) {
92 ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
93 info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
94 info.perf_event.uprobe.name_len = sizeof(buf);
95 goto again;
96 }
97
98 err = strncmp(u64_to_ptr(info.perf_event.uprobe.file_name), UPROBE_FILE,
99 strlen(UPROBE_FILE));
100 ASSERT_EQ(err, 0, "cmp_file_name");
101 break;
102 default:
103 err = -1;
104 break;
105 }
106 return err;
107 }
108
kprobe_fill_invalid_user_buffer(int fd)109 static void kprobe_fill_invalid_user_buffer(int fd)
110 {
111 struct bpf_link_info info;
112 __u32 len = sizeof(info);
113 int err;
114
115 memset(&info, 0, sizeof(info));
116
117 info.perf_event.kprobe.func_name = 0x1; /* invalid address */
118 err = bpf_link_get_info_by_fd(fd, &info, &len);
119 ASSERT_EQ(err, -EINVAL, "invalid_buff_and_len");
120
121 info.perf_event.kprobe.name_len = 64;
122 err = bpf_link_get_info_by_fd(fd, &info, &len);
123 ASSERT_EQ(err, -EFAULT, "invalid_buff");
124
125 info.perf_event.kprobe.func_name = 0;
126 err = bpf_link_get_info_by_fd(fd, &info, &len);
127 ASSERT_EQ(err, -EINVAL, "invalid_len");
128
129 ASSERT_EQ(info.perf_event.kprobe.addr, 0, "func_addr");
130 ASSERT_EQ(info.perf_event.kprobe.offset, 0, "func_offset");
131 ASSERT_EQ(info.perf_event.type, 0, "type");
132 }
133
test_kprobe_fill_link_info(struct test_fill_link_info * skel,enum bpf_perf_event_type type,bool invalid)134 static void test_kprobe_fill_link_info(struct test_fill_link_info *skel,
135 enum bpf_perf_event_type type,
136 bool invalid)
137 {
138 DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts,
139 .attach_mode = PROBE_ATTACH_MODE_LINK,
140 .retprobe = type == BPF_PERF_EVENT_KRETPROBE,
141 );
142 ssize_t entry_offset = 0;
143 int link_fd, err;
144
145 skel->links.kprobe_run = bpf_program__attach_kprobe_opts(skel->progs.kprobe_run,
146 KPROBE_FUNC, &opts);
147 if (!ASSERT_OK_PTR(skel->links.kprobe_run, "attach_kprobe"))
148 return;
149
150 link_fd = bpf_link__fd(skel->links.kprobe_run);
151 if (!invalid) {
152 /* See also arch_adjust_kprobe_addr(). */
153 if (skel->kconfig->CONFIG_X86_KERNEL_IBT)
154 entry_offset = 4;
155 err = verify_perf_link_info(link_fd, type, kprobe_addr, 0, entry_offset);
156 ASSERT_OK(err, "verify_perf_link_info");
157 } else {
158 kprobe_fill_invalid_user_buffer(link_fd);
159 }
160 bpf_link__detach(skel->links.kprobe_run);
161 }
162
test_tp_fill_link_info(struct test_fill_link_info * skel)163 static void test_tp_fill_link_info(struct test_fill_link_info *skel)
164 {
165 int link_fd, err;
166
167 skel->links.tp_run = bpf_program__attach_tracepoint(skel->progs.tp_run, TP_CAT, TP_NAME);
168 if (!ASSERT_OK_PTR(skel->links.tp_run, "attach_tp"))
169 return;
170
171 link_fd = bpf_link__fd(skel->links.tp_run);
172 err = verify_perf_link_info(link_fd, BPF_PERF_EVENT_TRACEPOINT, 0, 0, 0);
173 ASSERT_OK(err, "verify_perf_link_info");
174 bpf_link__detach(skel->links.tp_run);
175 }
176
test_uprobe_fill_link_info(struct test_fill_link_info * skel,enum bpf_perf_event_type type)177 static void test_uprobe_fill_link_info(struct test_fill_link_info *skel,
178 enum bpf_perf_event_type type)
179 {
180 int link_fd, err;
181
182 skel->links.uprobe_run = bpf_program__attach_uprobe(skel->progs.uprobe_run,
183 type == BPF_PERF_EVENT_URETPROBE,
184 0, /* self pid */
185 UPROBE_FILE, uprobe_offset);
186 if (!ASSERT_OK_PTR(skel->links.uprobe_run, "attach_uprobe"))
187 return;
188
189 link_fd = bpf_link__fd(skel->links.uprobe_run);
190 err = verify_perf_link_info(link_fd, type, 0, uprobe_offset, 0);
191 ASSERT_OK(err, "verify_perf_link_info");
192 bpf_link__detach(skel->links.uprobe_run);
193 }
194
verify_kmulti_link_info(int fd,bool retprobe)195 static int verify_kmulti_link_info(int fd, bool retprobe)
196 {
197 struct bpf_link_info info;
198 __u32 len = sizeof(info);
199 __u64 addrs[KMULTI_CNT];
200 int flags, i, err;
201
202 memset(&info, 0, sizeof(info));
203
204 again:
205 err = bpf_link_get_info_by_fd(fd, &info, &len);
206 if (!ASSERT_OK(err, "get_link_info"))
207 return -1;
208
209 if (!ASSERT_EQ(info.type, BPF_LINK_TYPE_KPROBE_MULTI, "kmulti_type"))
210 return -1;
211
212 ASSERT_EQ(info.kprobe_multi.count, KMULTI_CNT, "func_cnt");
213 flags = info.kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN;
214 if (!retprobe)
215 ASSERT_EQ(flags, 0, "kmulti_flags");
216 else
217 ASSERT_NEQ(flags, 0, "kretmulti_flags");
218
219 if (!info.kprobe_multi.addrs) {
220 info.kprobe_multi.addrs = ptr_to_u64(addrs);
221 goto again;
222 }
223 for (i = 0; i < KMULTI_CNT; i++)
224 ASSERT_EQ(addrs[i], kmulti_addrs[i], "kmulti_addrs");
225 return 0;
226 }
227
verify_kmulti_invalid_user_buffer(int fd)228 static void verify_kmulti_invalid_user_buffer(int fd)
229 {
230 struct bpf_link_info info;
231 __u32 len = sizeof(info);
232 __u64 addrs[KMULTI_CNT];
233 int err, i;
234
235 memset(&info, 0, sizeof(info));
236
237 info.kprobe_multi.count = KMULTI_CNT;
238 err = bpf_link_get_info_by_fd(fd, &info, &len);
239 ASSERT_EQ(err, -EINVAL, "no_addr");
240
241 info.kprobe_multi.addrs = ptr_to_u64(addrs);
242 info.kprobe_multi.count = 0;
243 err = bpf_link_get_info_by_fd(fd, &info, &len);
244 ASSERT_EQ(err, -EINVAL, "no_cnt");
245
246 for (i = 0; i < KMULTI_CNT; i++)
247 addrs[i] = 0;
248 info.kprobe_multi.count = KMULTI_CNT - 1;
249 err = bpf_link_get_info_by_fd(fd, &info, &len);
250 ASSERT_EQ(err, -ENOSPC, "smaller_cnt");
251 for (i = 0; i < KMULTI_CNT - 1; i++)
252 ASSERT_EQ(addrs[i], kmulti_addrs[i], "kmulti_addrs");
253 ASSERT_EQ(addrs[i], 0, "kmulti_addrs");
254
255 for (i = 0; i < KMULTI_CNT; i++)
256 addrs[i] = 0;
257 info.kprobe_multi.count = KMULTI_CNT + 1;
258 err = bpf_link_get_info_by_fd(fd, &info, &len);
259 ASSERT_EQ(err, 0, "bigger_cnt");
260 for (i = 0; i < KMULTI_CNT; i++)
261 ASSERT_EQ(addrs[i], kmulti_addrs[i], "kmulti_addrs");
262
263 info.kprobe_multi.count = KMULTI_CNT;
264 info.kprobe_multi.addrs = 0x1; /* invalid addr */
265 err = bpf_link_get_info_by_fd(fd, &info, &len);
266 ASSERT_EQ(err, -EFAULT, "invalid_buff");
267 }
268
symbols_cmp_r(const void * a,const void * b)269 static int symbols_cmp_r(const void *a, const void *b)
270 {
271 const char **str_a = (const char **) a;
272 const char **str_b = (const char **) b;
273
274 return strcmp(*str_a, *str_b);
275 }
276
test_kprobe_multi_fill_link_info(struct test_fill_link_info * skel,bool retprobe,bool invalid)277 static void test_kprobe_multi_fill_link_info(struct test_fill_link_info *skel,
278 bool retprobe, bool invalid)
279 {
280 LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
281 int link_fd, err;
282
283 opts.syms = kmulti_syms;
284 opts.cnt = KMULTI_CNT;
285 opts.retprobe = retprobe;
286 skel->links.kmulti_run = bpf_program__attach_kprobe_multi_opts(skel->progs.kmulti_run,
287 NULL, &opts);
288 if (!ASSERT_OK_PTR(skel->links.kmulti_run, "attach_kprobe_multi"))
289 return;
290
291 link_fd = bpf_link__fd(skel->links.kmulti_run);
292 if (!invalid) {
293 err = verify_kmulti_link_info(link_fd, retprobe);
294 ASSERT_OK(err, "verify_kmulti_link_info");
295 } else {
296 verify_kmulti_invalid_user_buffer(link_fd);
297 }
298 bpf_link__detach(skel->links.kmulti_run);
299 }
300
test_fill_link_info(void)301 void test_fill_link_info(void)
302 {
303 struct test_fill_link_info *skel;
304 int i;
305
306 skel = test_fill_link_info__open_and_load();
307 if (!ASSERT_OK_PTR(skel, "skel_open"))
308 return;
309
310 /* load kallsyms to compare the addr */
311 if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh"))
312 goto cleanup;
313
314 kprobe_addr = ksym_get_addr(KPROBE_FUNC);
315 if (test__start_subtest("kprobe_link_info"))
316 test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false);
317 if (test__start_subtest("kretprobe_link_info"))
318 test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KRETPROBE, false);
319 if (test__start_subtest("kprobe_invalid_ubuff"))
320 test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, true);
321 if (test__start_subtest("tracepoint_link_info"))
322 test_tp_fill_link_info(skel);
323
324 uprobe_offset = get_uprobe_offset(&uprobe_func);
325 if (test__start_subtest("uprobe_link_info"))
326 test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_UPROBE);
327 if (test__start_subtest("uretprobe_link_info"))
328 test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_URETPROBE);
329
330 qsort(kmulti_syms, KMULTI_CNT, sizeof(kmulti_syms[0]), symbols_cmp_r);
331 for (i = 0; i < KMULTI_CNT; i++)
332 kmulti_addrs[i] = ksym_get_addr(kmulti_syms[i]);
333 if (test__start_subtest("kprobe_multi_link_info"))
334 test_kprobe_multi_fill_link_info(skel, false, false);
335 if (test__start_subtest("kretprobe_multi_link_info"))
336 test_kprobe_multi_fill_link_info(skel, true, false);
337 if (test__start_subtest("kprobe_multi_invalid_ubuff"))
338 test_kprobe_multi_fill_link_info(skel, true, true);
339
340 cleanup:
341 test_fill_link_info__destroy(skel);
342 }
343
