1 | // SPDX-License-Identifier: GPL-2.0 |
2 | |
3 | #define _GNU_SOURCE |
4 | #include <errno.h> |
5 | #include <fcntl.h> |
6 | #include <linux/netlink.h> |
7 | #include <signal.h> |
8 | #include <stdbool.h> |
9 | #include <stdio.h> |
10 | #include <stdlib.h> |
11 | #include <string.h> |
12 | #include <sys/prctl.h> |
13 | #include <sys/socket.h> |
14 | #include <sched.h> |
15 | #include <sys/eventfd.h> |
16 | #include <sys/stat.h> |
17 | #include <sys/syscall.h> |
18 | #include <sys/types.h> |
19 | #include <sys/wait.h> |
20 | #include <unistd.h> |
21 | |
22 | #include "../kselftest_harness.h" |
23 | |
24 | #define __DEV_FULL "/sys/devices/virtual/mem/full/uevent" |
25 | #define __UEVENT_BUFFER_SIZE (2048 * 2) |
26 | #define "add@/devices/virtual/mem/full" |
27 | #define sizeof("add@/devices/virtual/mem/full") |
28 | #define __UEVENT_LISTEN_ALL -1 |
29 | |
30 | ssize_t read_nointr(int fd, void *buf, size_t count) |
31 | { |
32 | ssize_t ret; |
33 | |
34 | again: |
35 | ret = read(fd, buf, count); |
36 | if (ret < 0 && errno == EINTR) |
37 | goto again; |
38 | |
39 | return ret; |
40 | } |
41 | |
42 | ssize_t write_nointr(int fd, const void *buf, size_t count) |
43 | { |
44 | ssize_t ret; |
45 | |
46 | again: |
47 | ret = write(fd, buf, count); |
48 | if (ret < 0 && errno == EINTR) |
49 | goto again; |
50 | |
51 | return ret; |
52 | } |
53 | |
54 | int wait_for_pid(pid_t pid) |
55 | { |
56 | int status, ret; |
57 | |
58 | again: |
59 | ret = waitpid(pid, &status, 0); |
60 | if (ret == -1) { |
61 | if (errno == EINTR) |
62 | goto again; |
63 | |
64 | return -1; |
65 | } |
66 | |
67 | if (ret != pid) |
68 | goto again; |
69 | |
70 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) |
71 | return -1; |
72 | |
73 | return 0; |
74 | } |
75 | |
76 | static int uevent_listener(unsigned long post_flags, bool expect_uevent, |
77 | int sync_fd) |
78 | { |
79 | int sk_fd, ret; |
80 | socklen_t sk_addr_len; |
81 | int rcv_buf_sz = __UEVENT_BUFFER_SIZE; |
82 | uint64_t sync_add = 1; |
83 | struct sockaddr_nl sk_addr = { 0 }, rcv_addr = { 0 }; |
84 | char buf[__UEVENT_BUFFER_SIZE] = { 0 }; |
85 | struct iovec iov = { buf, __UEVENT_BUFFER_SIZE }; |
86 | char control[CMSG_SPACE(sizeof(struct ucred))]; |
87 | struct msghdr hdr = { |
88 | &rcv_addr, sizeof(rcv_addr), &iov, 1, |
89 | control, sizeof(control), 0, |
90 | }; |
91 | |
92 | sk_fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, |
93 | NETLINK_KOBJECT_UEVENT); |
94 | if (sk_fd < 0) { |
95 | fprintf(stderr, "%s - Failed to open uevent socket\n" , strerror(errno)); |
96 | return -1; |
97 | } |
98 | |
99 | ret = setsockopt(sk_fd, SOL_SOCKET, SO_RCVBUF, &rcv_buf_sz, |
100 | sizeof(rcv_buf_sz)); |
101 | if (ret < 0) { |
102 | fprintf(stderr, "%s - Failed to set socket options\n" , strerror(errno)); |
103 | goto on_error; |
104 | } |
105 | |
106 | sk_addr.nl_family = AF_NETLINK; |
107 | sk_addr.nl_groups = __UEVENT_LISTEN_ALL; |
108 | |
109 | sk_addr_len = sizeof(sk_addr); |
110 | ret = bind(sk_fd, (struct sockaddr *)&sk_addr, sk_addr_len); |
111 | if (ret < 0) { |
112 | fprintf(stderr, "%s - Failed to bind socket\n" , strerror(errno)); |
113 | goto on_error; |
114 | } |
115 | |
116 | ret = getsockname(sk_fd, (struct sockaddr *)&sk_addr, &sk_addr_len); |
117 | if (ret < 0) { |
118 | fprintf(stderr, "%s - Failed to retrieve socket name\n" , strerror(errno)); |
119 | goto on_error; |
120 | } |
121 | |
122 | if ((size_t)sk_addr_len != sizeof(sk_addr)) { |
123 | fprintf(stderr, "Invalid socket address size\n" ); |
124 | ret = -1; |
125 | goto on_error; |
126 | } |
127 | |
128 | if (post_flags & CLONE_NEWUSER) { |
129 | ret = unshare(CLONE_NEWUSER); |
130 | if (ret < 0) { |
131 | fprintf(stderr, |
132 | "%s - Failed to unshare user namespace\n" , |
133 | strerror(errno)); |
134 | goto on_error; |
135 | } |
136 | } |
137 | |
138 | if (post_flags & CLONE_NEWNET) { |
139 | ret = unshare(CLONE_NEWNET); |
140 | if (ret < 0) { |
141 | fprintf(stderr, |
142 | "%s - Failed to unshare network namespace\n" , |
143 | strerror(errno)); |
144 | goto on_error; |
145 | } |
146 | } |
147 | |
148 | ret = write_nointr(fd: sync_fd, buf: &sync_add, count: sizeof(sync_add)); |
149 | close(sync_fd); |
150 | if (ret != sizeof(sync_add)) { |
151 | ret = -1; |
152 | fprintf(stderr, "Failed to synchronize with parent process\n" ); |
153 | goto on_error; |
154 | } |
155 | |
156 | ret = 0; |
157 | for (;;) { |
158 | ssize_t r; |
159 | |
160 | r = recvmsg(sk_fd, &hdr, 0); |
161 | if (r <= 0) { |
162 | fprintf(stderr, "%s - Failed to receive uevent\n" , strerror(errno)); |
163 | ret = -1; |
164 | break; |
165 | } |
166 | |
167 | /* ignore libudev messages */ |
168 | if (memcmp(p: buf, q: "libudev" , size: 8) == 0) |
169 | continue; |
170 | |
171 | /* ignore uevents we didn't trigger */ |
172 | if (memcmp(p: buf, __UEVENT_HEADER, __UEVENT_HEADER_LEN) != 0) |
173 | continue; |
174 | |
175 | if (!expect_uevent) { |
176 | fprintf(stderr, "Received unexpected uevent:\n" ); |
177 | ret = -1; |
178 | } |
179 | |
180 | if (TH_LOG_ENABLED) { |
181 | /* If logging is enabled dump the received uevent. */ |
182 | (void)write_nointr(STDERR_FILENO, buf, r); |
183 | (void)write_nointr(STDERR_FILENO, "\n" , 1); |
184 | } |
185 | |
186 | break; |
187 | } |
188 | |
189 | on_error: |
190 | close(sk_fd); |
191 | |
192 | return ret; |
193 | } |
194 | |
195 | int trigger_uevent(unsigned int times) |
196 | { |
197 | int fd, ret; |
198 | unsigned int i; |
199 | |
200 | fd = open(__DEV_FULL, O_RDWR | O_CLOEXEC); |
201 | if (fd < 0) { |
202 | if (errno != ENOENT) |
203 | return -EINVAL; |
204 | |
205 | return -1; |
206 | } |
207 | |
208 | for (i = 0; i < times; i++) { |
209 | ret = write_nointr(fd, buf: "add\n" , count: sizeof("add\n" ) - 1); |
210 | if (ret < 0) { |
211 | fprintf(stderr, "Failed to trigger uevent\n" ); |
212 | break; |
213 | } |
214 | } |
215 | close(fd); |
216 | |
217 | return ret; |
218 | } |
219 | |
220 | int set_death_signal(void) |
221 | { |
222 | int ret; |
223 | pid_t ppid; |
224 | |
225 | ret = prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); |
226 | |
227 | /* Check whether we have been orphaned. */ |
228 | ppid = getppid(); |
229 | if (ppid == 1) { |
230 | pid_t self; |
231 | |
232 | self = getpid(); |
233 | ret = kill(self, SIGKILL); |
234 | } |
235 | |
236 | if (ret < 0) |
237 | return -1; |
238 | |
239 | return 0; |
240 | } |
241 | |
242 | static int do_test(unsigned long pre_flags, unsigned long post_flags, |
243 | bool expect_uevent, int sync_fd) |
244 | { |
245 | int ret; |
246 | uint64_t wait_val; |
247 | pid_t pid; |
248 | sigset_t mask; |
249 | sigset_t orig_mask; |
250 | struct timespec timeout; |
251 | |
252 | sigemptyset(set: &mask); |
253 | sigaddset(set: &mask, SIGCHLD); |
254 | |
255 | ret = sigprocmask(SIG_BLOCK, &mask, &orig_mask); |
256 | if (ret < 0) { |
257 | fprintf(stderr, "%s- Failed to block SIGCHLD\n" , strerror(errno)); |
258 | return -1; |
259 | } |
260 | |
261 | pid = fork(); |
262 | if (pid < 0) { |
263 | fprintf(stderr, "%s - Failed to fork() new process\n" , strerror(errno)); |
264 | return -1; |
265 | } |
266 | |
267 | if (pid == 0) { |
268 | /* Make sure that we go away when our parent dies. */ |
269 | ret = set_death_signal(); |
270 | if (ret < 0) { |
271 | fprintf(stderr, "Failed to set PR_SET_PDEATHSIG to SIGKILL\n" ); |
272 | _exit(EXIT_FAILURE); |
273 | } |
274 | |
275 | if (pre_flags & CLONE_NEWUSER) { |
276 | ret = unshare(CLONE_NEWUSER); |
277 | if (ret < 0) { |
278 | fprintf(stderr, |
279 | "%s - Failed to unshare user namespace\n" , |
280 | strerror(errno)); |
281 | _exit(EXIT_FAILURE); |
282 | } |
283 | } |
284 | |
285 | if (pre_flags & CLONE_NEWNET) { |
286 | ret = unshare(CLONE_NEWNET); |
287 | if (ret < 0) { |
288 | fprintf(stderr, |
289 | "%s - Failed to unshare network namespace\n" , |
290 | strerror(errno)); |
291 | _exit(EXIT_FAILURE); |
292 | } |
293 | } |
294 | |
295 | if (uevent_listener(post_flags, expect_uevent, sync_fd) < 0) |
296 | _exit(EXIT_FAILURE); |
297 | |
298 | _exit(EXIT_SUCCESS); |
299 | } |
300 | |
301 | ret = read_nointr(fd: sync_fd, buf: &wait_val, count: sizeof(wait_val)); |
302 | if (ret != sizeof(wait_val)) { |
303 | fprintf(stderr, "Failed to synchronize with child process\n" ); |
304 | _exit(EXIT_FAILURE); |
305 | } |
306 | |
307 | /* Trigger 10 uevents to account for the case where the kernel might |
308 | * drop some. |
309 | */ |
310 | ret = trigger_uevent(times: 10); |
311 | if (ret < 0) |
312 | fprintf(stderr, "Failed triggering uevents\n" ); |
313 | |
314 | /* Wait for 2 seconds before considering this failed. This should be |
315 | * plenty of time for the kernel to deliver the uevent even under heavy |
316 | * load. |
317 | */ |
318 | timeout.tv_sec = 2; |
319 | timeout.tv_nsec = 0; |
320 | |
321 | again: |
322 | ret = sigtimedwait(&mask, NULL, &timeout); |
323 | if (ret < 0) { |
324 | if (errno == EINTR) |
325 | goto again; |
326 | |
327 | if (!expect_uevent) |
328 | ret = kill(pid, SIGTERM); /* success */ |
329 | else |
330 | ret = kill(pid, SIGUSR1); /* error */ |
331 | if (ret < 0) |
332 | return -1; |
333 | } |
334 | |
335 | ret = wait_for_pid(pid); |
336 | if (ret < 0) |
337 | return -1; |
338 | |
339 | return ret; |
340 | } |
341 | |
342 | static void signal_handler(int sig) |
343 | { |
344 | if (sig == SIGTERM) |
345 | _exit(EXIT_SUCCESS); |
346 | |
347 | _exit(EXIT_FAILURE); |
348 | } |
349 | |
350 | TEST(uevent_filtering) |
351 | { |
352 | int ret, sync_fd; |
353 | struct sigaction act; |
354 | |
355 | if (geteuid()) { |
356 | TH_LOG("Uevent filtering tests require root privileges. Skipping test" ); |
357 | _exit(KSFT_SKIP); |
358 | } |
359 | |
360 | ret = access(__DEV_FULL, F_OK); |
361 | EXPECT_EQ(0, ret) { |
362 | if (errno == ENOENT) { |
363 | TH_LOG(__DEV_FULL " does not exist. Skipping test" ); |
364 | _exit(KSFT_SKIP); |
365 | } |
366 | |
367 | _exit(KSFT_FAIL); |
368 | } |
369 | |
370 | act.sa_handler = signal_handler; |
371 | act.sa_flags = 0; |
372 | sigemptyset(set: &act.sa_mask); |
373 | |
374 | ret = sigaction(SIGTERM, &act, NULL); |
375 | ASSERT_EQ(0, ret); |
376 | |
377 | sync_fd = eventfd(0, EFD_CLOEXEC); |
378 | ASSERT_GE(sync_fd, 0); |
379 | |
380 | /* |
381 | * Setup: |
382 | * - Open uevent listening socket in initial network namespace owned by |
383 | * initial user namespace. |
384 | * - Trigger uevent in initial network namespace owned by initial user |
385 | * namespace. |
386 | * Expected Result: |
387 | * - uevent listening socket receives uevent |
388 | */ |
389 | ret = do_test(pre_flags: 0, post_flags: 0, expect_uevent: true, sync_fd); |
390 | ASSERT_EQ(0, ret) { |
391 | goto do_cleanup; |
392 | } |
393 | |
394 | /* |
395 | * Setup: |
396 | * - Open uevent listening socket in non-initial network namespace |
397 | * owned by initial user namespace. |
398 | * - Trigger uevent in initial network namespace owned by initial user |
399 | * namespace. |
400 | * Expected Result: |
401 | * - uevent listening socket receives uevent |
402 | */ |
403 | ret = do_test(CLONE_NEWNET, post_flags: 0, expect_uevent: true, sync_fd); |
404 | ASSERT_EQ(0, ret) { |
405 | goto do_cleanup; |
406 | } |
407 | |
408 | /* |
409 | * Setup: |
410 | * - unshare user namespace |
411 | * - Open uevent listening socket in initial network namespace |
412 | * owned by initial user namespace. |
413 | * - Trigger uevent in initial network namespace owned by initial user |
414 | * namespace. |
415 | * Expected Result: |
416 | * - uevent listening socket receives uevent |
417 | */ |
418 | ret = do_test(CLONE_NEWUSER, post_flags: 0, expect_uevent: true, sync_fd); |
419 | ASSERT_EQ(0, ret) { |
420 | goto do_cleanup; |
421 | } |
422 | |
423 | /* |
424 | * Setup: |
425 | * - Open uevent listening socket in non-initial network namespace |
426 | * owned by non-initial user namespace. |
427 | * - Trigger uevent in initial network namespace owned by initial user |
428 | * namespace. |
429 | * Expected Result: |
430 | * - uevent listening socket receives no uevent |
431 | */ |
432 | ret = do_test(CLONE_NEWUSER | CLONE_NEWNET, post_flags: 0, expect_uevent: false, sync_fd); |
433 | ASSERT_EQ(0, ret) { |
434 | goto do_cleanup; |
435 | } |
436 | |
437 | /* |
438 | * Setup: |
439 | * - Open uevent listening socket in initial network namespace |
440 | * owned by initial user namespace. |
441 | * - unshare network namespace |
442 | * - Trigger uevent in initial network namespace owned by initial user |
443 | * namespace. |
444 | * Expected Result: |
445 | * - uevent listening socket receives uevent |
446 | */ |
447 | ret = do_test(pre_flags: 0, CLONE_NEWNET, expect_uevent: true, sync_fd); |
448 | ASSERT_EQ(0, ret) { |
449 | goto do_cleanup; |
450 | } |
451 | |
452 | /* |
453 | * Setup: |
454 | * - Open uevent listening socket in initial network namespace |
455 | * owned by initial user namespace. |
456 | * - unshare user namespace |
457 | * - Trigger uevent in initial network namespace owned by initial user |
458 | * namespace. |
459 | * Expected Result: |
460 | * - uevent listening socket receives uevent |
461 | */ |
462 | ret = do_test(pre_flags: 0, CLONE_NEWUSER, expect_uevent: true, sync_fd); |
463 | ASSERT_EQ(0, ret) { |
464 | goto do_cleanup; |
465 | } |
466 | |
467 | /* |
468 | * Setup: |
469 | * - Open uevent listening socket in initial network namespace |
470 | * owned by initial user namespace. |
471 | * - unshare user namespace |
472 | * - unshare network namespace |
473 | * - Trigger uevent in initial network namespace owned by initial user |
474 | * namespace. |
475 | * Expected Result: |
476 | * - uevent listening socket receives uevent |
477 | */ |
478 | ret = do_test(pre_flags: 0, CLONE_NEWUSER | CLONE_NEWNET, expect_uevent: true, sync_fd); |
479 | ASSERT_EQ(0, ret) { |
480 | goto do_cleanup; |
481 | } |
482 | |
483 | do_cleanup: |
484 | close(sync_fd); |
485 | } |
486 | |
487 | TEST_HARNESS_MAIN |
488 | |