1 // SPDX-License-Identifier: GPL-2.0
2
3 /*
4 * Based on Christian Brauner's clone3() example.
5 * These tests are assuming to be running in the host's
6 * PID namespace.
7 */
8
9 #define _GNU_SOURCE
10 #include <errno.h>
11 #include <linux/types.h>
12 #include <linux/sched.h>
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <stdbool.h>
16 #include <sys/syscall.h>
17 #include <sys/types.h>
18 #include <sys/un.h>
19 #include <sys/wait.h>
20 #include <unistd.h>
21 #include <sched.h>
22
23 #include "../kselftest.h"
24 #include "clone3_selftests.h"
25
26 #ifndef MAX_PID_NS_LEVEL
27 #define MAX_PID_NS_LEVEL 32
28 #endif
29
30 static int pipe_1[2];
31 static int pipe_2[2];
32
child_exit(int ret)33 static void child_exit(int ret)
34 {
35 fflush(stdout);
36 fflush(stderr);
37 _exit(ret);
38 }
39
call_clone3_set_tid(pid_t * set_tid,size_t set_tid_size,int flags,int expected_pid,bool wait_for_it)40 static int call_clone3_set_tid(pid_t *set_tid,
41 size_t set_tid_size,
42 int flags,
43 int expected_pid,
44 bool wait_for_it)
45 {
46 int status;
47 pid_t pid = -1;
48
49 struct clone_args args = {
50 .flags = flags,
51 .exit_signal = SIGCHLD,
52 .set_tid = ptr_to_u64(set_tid),
53 .set_tid_size = set_tid_size,
54 };
55
56 pid = sys_clone3(&args, sizeof(struct clone_args));
57 if (pid < 0) {
58 ksft_print_msg("%s - Failed to create new process\n",
59 strerror(errno));
60 return -errno;
61 }
62
63 if (pid == 0) {
64 int ret;
65 char tmp = 0;
66 int exit_code = EXIT_SUCCESS;
67
68 ksft_print_msg("I am the child, my PID is %d (expected %d)\n",
69 getpid(), set_tid[0]);
70 if (wait_for_it) {
71 ksft_print_msg("[%d] Child is ready and waiting\n",
72 getpid());
73
74 /* Signal the parent that the child is ready */
75 close(pipe_1[0]);
76 ret = write(pipe_1[1], &tmp, 1);
77 if (ret != 1) {
78 ksft_print_msg(
79 "Writing to pipe returned %d", ret);
80 exit_code = EXIT_FAILURE;
81 }
82 close(pipe_1[1]);
83 close(pipe_2[1]);
84 ret = read(pipe_2[0], &tmp, 1);
85 if (ret != 1) {
86 ksft_print_msg(
87 "Reading from pipe returned %d", ret);
88 exit_code = EXIT_FAILURE;
89 }
90 close(pipe_2[0]);
91 }
92
93 if (set_tid[0] != getpid())
94 child_exit(EXIT_FAILURE);
95 child_exit(exit_code);
96 }
97
98 if (expected_pid == 0 || expected_pid == pid) {
99 ksft_print_msg("I am the parent (%d). My child's pid is %d\n",
100 getpid(), pid);
101 } else {
102 ksft_print_msg(
103 "Expected child pid %d does not match actual pid %d\n",
104 expected_pid, pid);
105 return -1;
106 }
107
108 if (waitpid(pid, &status, 0) < 0) {
109 ksft_print_msg("Child returned %s\n", strerror(errno));
110 return -errno;
111 }
112
113 if (!WIFEXITED(status))
114 return -1;
115
116 return WEXITSTATUS(status);
117 }
118
test_clone3_set_tid(pid_t * set_tid,size_t set_tid_size,int flags,int expected,int expected_pid,bool wait_for_it)119 static void test_clone3_set_tid(pid_t *set_tid,
120 size_t set_tid_size,
121 int flags,
122 int expected,
123 int expected_pid,
124 bool wait_for_it)
125 {
126 int ret;
127
128 ksft_print_msg(
129 "[%d] Trying clone3() with CLONE_SET_TID to %d and 0x%x\n",
130 getpid(), set_tid[0], flags);
131 ret = call_clone3_set_tid(set_tid, set_tid_size, flags, expected_pid,
132 wait_for_it);
133 ksft_print_msg(
134 "[%d] clone3() with CLONE_SET_TID %d says :%d - expected %d\n",
135 getpid(), set_tid[0], ret, expected);
136 if (ret != expected)
137 ksft_test_result_fail(
138 "[%d] Result (%d) is different than expected (%d)\n",
139 getpid(), ret, expected);
140 else
141 ksft_test_result_pass(
142 "[%d] Result (%d) matches expectation (%d)\n",
143 getpid(), ret, expected);
144 }
main(int argc,char * argv[])145 int main(int argc, char *argv[])
146 {
147 FILE *f;
148 char buf;
149 char *line;
150 int status;
151 int ret = -1;
152 size_t len = 0;
153 int pid_max = 0;
154 uid_t uid = getuid();
155 char proc_path[100] = {0};
156 pid_t pid, ns1, ns2, ns3, ns_pid;
157 pid_t set_tid[MAX_PID_NS_LEVEL * 2];
158
159 ksft_print_header();
160 test_clone3_supported();
161 ksft_set_plan(29);
162
163 if (pipe(pipe_1) < 0 || pipe(pipe_2) < 0)
164 ksft_exit_fail_msg("pipe() failed\n");
165
166 f = fopen("/proc/sys/kernel/pid_max", "r");
167 if (f == NULL)
168 ksft_exit_fail_msg(
169 "%s - Could not open /proc/sys/kernel/pid_max\n",
170 strerror(errno));
171 fscanf(f, "%d", &pid_max);
172 fclose(f);
173 ksft_print_msg("/proc/sys/kernel/pid_max %d\n", pid_max);
174
175 /* Try invalid settings */
176 memset(&set_tid, 0, sizeof(set_tid));
177 test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL + 1, 0, -EINVAL, 0, 0);
178
179 test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2, 0, -EINVAL, 0, 0);
180
181 test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2 + 1, 0,
182 -EINVAL, 0, 0);
183
184 test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 42, 0, -EINVAL, 0, 0);
185
186 /*
187 * This can actually work if this test running in a MAX_PID_NS_LEVEL - 1
188 * nested PID namespace.
189 */
190 test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL - 1, 0, -EINVAL, 0, 0);
191
192 memset(&set_tid, 0xff, sizeof(set_tid));
193 test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL + 1, 0, -EINVAL, 0, 0);
194
195 test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2, 0, -EINVAL, 0, 0);
196
197 test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2 + 1, 0,
198 -EINVAL, 0, 0);
199
200 test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 42, 0, -EINVAL, 0, 0);
201
202 /*
203 * This can actually work if this test running in a MAX_PID_NS_LEVEL - 1
204 * nested PID namespace.
205 */
206 test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL - 1, 0, -EINVAL, 0, 0);
207
208 memset(&set_tid, 0, sizeof(set_tid));
209 /* Try with an invalid PID */
210 set_tid[0] = 0;
211 test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
212
213 set_tid[0] = -1;
214 test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
215
216 /* Claim that the set_tid array actually contains 2 elements. */
217 test_clone3_set_tid(set_tid, 2, 0, -EINVAL, 0, 0);
218
219 /* Try it in a new PID namespace */
220 if (uid == 0)
221 test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, -EINVAL, 0, 0);
222 else
223 ksft_test_result_skip("Clone3() with set_tid requires root\n");
224
225 /* Try with a valid PID (1) this should return -EEXIST. */
226 set_tid[0] = 1;
227 if (uid == 0)
228 test_clone3_set_tid(set_tid, 1, 0, -EEXIST, 0, 0);
229 else
230 ksft_test_result_skip("Clone3() with set_tid requires root\n");
231
232 /* Try it in a new PID namespace */
233 if (uid == 0)
234 test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, 0, 0, 0);
235 else
236 ksft_test_result_skip("Clone3() with set_tid requires root\n");
237
238 /* pid_max should fail everywhere */
239 set_tid[0] = pid_max;
240 test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
241
242 if (uid == 0)
243 test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, -EINVAL, 0, 0);
244 else
245 ksft_test_result_skip("Clone3() with set_tid requires root\n");
246
247 if (uid != 0) {
248 /*
249 * All remaining tests require root. Tell the framework
250 * that all those tests are skipped as non-root.
251 */
252 ksft_cnt.ksft_xskip += ksft_plan - ksft_test_num();
253 goto out;
254 }
255
256 /* Find the current active PID */
257 pid = fork();
258 if (pid == 0) {
259 ksft_print_msg("Child has PID %d\n", getpid());
260 child_exit(EXIT_SUCCESS);
261 }
262 if (waitpid(pid, &status, 0) < 0)
263 ksft_exit_fail_msg("Waiting for child %d failed", pid);
264
265 /* After the child has finished, its PID should be free. */
266 set_tid[0] = pid;
267 test_clone3_set_tid(set_tid, 1, 0, 0, 0, 0);
268
269 /* This should fail as there is no PID 1 in that namespace */
270 test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, -EINVAL, 0, 0);
271
272 /*
273 * Creating a process with PID 1 in the newly created most nested
274 * PID namespace and PID 'pid' in the parent PID namespace. This
275 * needs to work.
276 */
277 set_tid[0] = 1;
278 set_tid[1] = pid;
279 test_clone3_set_tid(set_tid, 2, CLONE_NEWPID, 0, pid, 0);
280
281 ksft_print_msg("unshare PID namespace\n");
282 if (unshare(CLONE_NEWPID) == -1)
283 ksft_exit_fail_msg("unshare(CLONE_NEWPID) failed: %s\n",
284 strerror(errno));
285
286 set_tid[0] = pid;
287
288 /* This should fail as there is no PID 1 in that namespace */
289 test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
290
291 /* Let's create a PID 1 */
292 ns_pid = fork();
293 if (ns_pid == 0) {
294 /*
295 * This and the next test cases check that all pid-s are
296 * released on error paths.
297 */
298 set_tid[0] = 43;
299 set_tid[1] = -1;
300 test_clone3_set_tid(set_tid, 2, 0, -EINVAL, 0, 0);
301
302 set_tid[0] = 43;
303 set_tid[1] = pid;
304 test_clone3_set_tid(set_tid, 2, 0, 0, 43, 0);
305
306 ksft_print_msg("Child in PID namespace has PID %d\n", getpid());
307 set_tid[0] = 2;
308 test_clone3_set_tid(set_tid, 1, 0, 0, 2, 0);
309
310 set_tid[0] = 1;
311 set_tid[1] = -1;
312 set_tid[2] = pid;
313 /* This should fail as there is invalid PID at level '1'. */
314 test_clone3_set_tid(set_tid, 3, CLONE_NEWPID, -EINVAL, 0, 0);
315
316 set_tid[0] = 1;
317 set_tid[1] = 42;
318 set_tid[2] = pid;
319 /*
320 * This should fail as there are not enough active PID
321 * namespaces. Again assuming this is running in the host's
322 * PID namespace. Not yet nested.
323 */
324 test_clone3_set_tid(set_tid, 4, CLONE_NEWPID, -EINVAL, 0, 0);
325
326 /*
327 * This should work and from the parent we should see
328 * something like 'NSpid: pid 42 1'.
329 */
330 test_clone3_set_tid(set_tid, 3, CLONE_NEWPID, 0, 42, true);
331
332 child_exit(ksft_cnt.ksft_fail);
333 }
334
335 close(pipe_1[1]);
336 close(pipe_2[0]);
337 while (read(pipe_1[0], &buf, 1) > 0) {
338 ksft_print_msg("[%d] Child is ready and waiting\n", getpid());
339 break;
340 }
341
342 snprintf(proc_path, sizeof(proc_path), "/proc/%d/status", pid);
343 f = fopen(proc_path, "r");
344 if (f == NULL)
345 ksft_exit_fail_msg(
346 "%s - Could not open %s\n",
347 strerror(errno), proc_path);
348
349 while (getline(&line, &len, f) != -1) {
350 if (strstr(line, "NSpid")) {
351 int i;
352
353 /* Verify that all generated PIDs are as expected. */
354 i = sscanf(line, "NSpid:\t%d\t%d\t%d",
355 &ns3, &ns2, &ns1);
356 if (i != 3) {
357 ksft_print_msg(
358 "Unexpected 'NSPid:' entry: %s",
359 line);
360 ns1 = ns2 = ns3 = 0;
361 }
362 break;
363 }
364 }
365 fclose(f);
366 free(line);
367 close(pipe_2[0]);
368
369 /* Tell the clone3()'d child to finish. */
370 write(pipe_2[1], &buf, 1);
371 close(pipe_2[1]);
372
373 if (waitpid(ns_pid, &status, 0) < 0) {
374 ksft_print_msg("Child returned %s\n", strerror(errno));
375 ret = -errno;
376 goto out;
377 }
378
379 if (!WIFEXITED(status))
380 ksft_test_result_fail("Child error\n");
381
382 ksft_cnt.ksft_pass += 6 - (ksft_cnt.ksft_fail - WEXITSTATUS(status));
383 ksft_cnt.ksft_fail = WEXITSTATUS(status);
384
385 if (ns3 == pid && ns2 == 42 && ns1 == 1)
386 ksft_test_result_pass(
387 "PIDs in all namespaces as expected (%d,%d,%d)\n",
388 ns3, ns2, ns1);
389 else
390 ksft_test_result_fail(
391 "PIDs in all namespaces not as expected (%d,%d,%d)\n",
392 ns3, ns2, ns1);
393 out:
394 ret = 0;
395
396 return !ret ? ksft_exit_pass() : ksft_exit_fail();
397 }
398