1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Landlock tests - Common user space base
4 *
5 * Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
6 * Copyright © 2019-2020 ANSSI
7 */
8
9 #define _GNU_SOURCE
10 #include <errno.h>
11 #include <fcntl.h>
12 #include <linux/keyctl.h>
13 #include <linux/landlock.h>
14 #include <string.h>
15 #include <sys/prctl.h>
16 #include <sys/socket.h>
17 #include <sys/types.h>
18
19 #include "common.h"
20
21 #ifndef O_PATH
22 #define O_PATH 010000000
23 #endif
24
TEST(inconsistent_attr)25 TEST(inconsistent_attr)
26 {
27 const long page_size = sysconf(_SC_PAGESIZE);
28 char *const buf = malloc(page_size + 1);
29 struct landlock_ruleset_attr *const ruleset_attr = (void *)buf;
30
31 ASSERT_NE(NULL, buf);
32
33 /* Checks copy_from_user(). */
34 ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, 0, 0));
35 /* The size if less than sizeof(struct landlock_attr_enforce). */
36 ASSERT_EQ(EINVAL, errno);
37 ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, 1, 0));
38 ASSERT_EQ(EINVAL, errno);
39 ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, 7, 0));
40 ASSERT_EQ(EINVAL, errno);
41
42 ASSERT_EQ(-1, landlock_create_ruleset(NULL, 1, 0));
43 /* The size if less than sizeof(struct landlock_attr_enforce). */
44 ASSERT_EQ(EFAULT, errno);
45
46 ASSERT_EQ(-1, landlock_create_ruleset(
47 NULL, sizeof(struct landlock_ruleset_attr), 0));
48 ASSERT_EQ(EFAULT, errno);
49
50 ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size + 1, 0));
51 ASSERT_EQ(E2BIG, errno);
52
53 /* Checks minimal valid attribute size. */
54 ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, 8, 0));
55 ASSERT_EQ(ENOMSG, errno);
56 ASSERT_EQ(-1, landlock_create_ruleset(
57 ruleset_attr,
58 sizeof(struct landlock_ruleset_attr), 0));
59 ASSERT_EQ(ENOMSG, errno);
60 ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size, 0));
61 ASSERT_EQ(ENOMSG, errno);
62
63 /* Checks non-zero value. */
64 buf[page_size - 2] = '.';
65 ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size, 0));
66 ASSERT_EQ(E2BIG, errno);
67
68 ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size + 1, 0));
69 ASSERT_EQ(E2BIG, errno);
70
71 free(buf);
72 }
73
TEST(abi_version)74 TEST(abi_version)
75 {
76 const struct landlock_ruleset_attr ruleset_attr = {
77 .handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
78 };
79 ASSERT_EQ(3, landlock_create_ruleset(NULL, 0,
80 LANDLOCK_CREATE_RULESET_VERSION));
81
82 ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0,
83 LANDLOCK_CREATE_RULESET_VERSION));
84 ASSERT_EQ(EINVAL, errno);
85
86 ASSERT_EQ(-1, landlock_create_ruleset(NULL, sizeof(ruleset_attr),
87 LANDLOCK_CREATE_RULESET_VERSION));
88 ASSERT_EQ(EINVAL, errno);
89
90 ASSERT_EQ(-1,
91 landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr),
92 LANDLOCK_CREATE_RULESET_VERSION));
93 ASSERT_EQ(EINVAL, errno);
94
95 ASSERT_EQ(-1, landlock_create_ruleset(NULL, 0,
96 LANDLOCK_CREATE_RULESET_VERSION |
97 1 << 31));
98 ASSERT_EQ(EINVAL, errno);
99 }
100
101 /* Tests ordering of syscall argument checks. */
TEST(create_ruleset_checks_ordering)102 TEST(create_ruleset_checks_ordering)
103 {
104 const int last_flag = LANDLOCK_CREATE_RULESET_VERSION;
105 const int invalid_flag = last_flag << 1;
106 int ruleset_fd;
107 const struct landlock_ruleset_attr ruleset_attr = {
108 .handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
109 };
110
111 /* Checks priority for invalid flags. */
112 ASSERT_EQ(-1, landlock_create_ruleset(NULL, 0, invalid_flag));
113 ASSERT_EQ(EINVAL, errno);
114
115 ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0, invalid_flag));
116 ASSERT_EQ(EINVAL, errno);
117
118 ASSERT_EQ(-1, landlock_create_ruleset(NULL, sizeof(ruleset_attr),
119 invalid_flag));
120 ASSERT_EQ(EINVAL, errno);
121
122 ASSERT_EQ(-1,
123 landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr),
124 invalid_flag));
125 ASSERT_EQ(EINVAL, errno);
126
127 /* Checks too big ruleset_attr size. */
128 ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, -1, 0));
129 ASSERT_EQ(E2BIG, errno);
130
131 /* Checks too small ruleset_attr size. */
132 ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0, 0));
133 ASSERT_EQ(EINVAL, errno);
134 ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 1, 0));
135 ASSERT_EQ(EINVAL, errno);
136
137 /* Checks valid call. */
138 ruleset_fd =
139 landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
140 ASSERT_LE(0, ruleset_fd);
141 ASSERT_EQ(0, close(ruleset_fd));
142 }
143
144 /* Tests ordering of syscall argument checks. */
TEST(add_rule_checks_ordering)145 TEST(add_rule_checks_ordering)
146 {
147 const struct landlock_ruleset_attr ruleset_attr = {
148 .handled_access_fs = LANDLOCK_ACCESS_FS_EXECUTE,
149 };
150 struct landlock_path_beneath_attr path_beneath_attr = {
151 .allowed_access = LANDLOCK_ACCESS_FS_EXECUTE,
152 .parent_fd = -1,
153 };
154 const int ruleset_fd =
155 landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
156
157 ASSERT_LE(0, ruleset_fd);
158
159 /* Checks invalid flags. */
160 ASSERT_EQ(-1, landlock_add_rule(-1, 0, NULL, 1));
161 ASSERT_EQ(EINVAL, errno);
162
163 /* Checks invalid ruleset FD. */
164 ASSERT_EQ(-1, landlock_add_rule(-1, 0, NULL, 0));
165 ASSERT_EQ(EBADF, errno);
166
167 /* Checks invalid rule type. */
168 ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, 0, NULL, 0));
169 ASSERT_EQ(EINVAL, errno);
170
171 /* Checks invalid rule attr. */
172 ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
173 NULL, 0));
174 ASSERT_EQ(EFAULT, errno);
175
176 /* Checks invalid path_beneath.parent_fd. */
177 ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
178 &path_beneath_attr, 0));
179 ASSERT_EQ(EBADF, errno);
180
181 /* Checks valid call. */
182 path_beneath_attr.parent_fd =
183 open("/tmp", O_PATH | O_NOFOLLOW | O_DIRECTORY | O_CLOEXEC);
184 ASSERT_LE(0, path_beneath_attr.parent_fd);
185 ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
186 &path_beneath_attr, 0));
187 ASSERT_EQ(0, close(path_beneath_attr.parent_fd));
188 ASSERT_EQ(0, close(ruleset_fd));
189 }
190
191 /* Tests ordering of syscall argument and permission checks. */
TEST(restrict_self_checks_ordering)192 TEST(restrict_self_checks_ordering)
193 {
194 const struct landlock_ruleset_attr ruleset_attr = {
195 .handled_access_fs = LANDLOCK_ACCESS_FS_EXECUTE,
196 };
197 struct landlock_path_beneath_attr path_beneath_attr = {
198 .allowed_access = LANDLOCK_ACCESS_FS_EXECUTE,
199 .parent_fd = -1,
200 };
201 const int ruleset_fd =
202 landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
203
204 ASSERT_LE(0, ruleset_fd);
205 path_beneath_attr.parent_fd =
206 open("/tmp", O_PATH | O_NOFOLLOW | O_DIRECTORY | O_CLOEXEC);
207 ASSERT_LE(0, path_beneath_attr.parent_fd);
208 ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
209 &path_beneath_attr, 0));
210 ASSERT_EQ(0, close(path_beneath_attr.parent_fd));
211
212 /* Checks unprivileged enforcement without no_new_privs. */
213 drop_caps(_metadata);
214 ASSERT_EQ(-1, landlock_restrict_self(-1, -1));
215 ASSERT_EQ(EPERM, errno);
216 ASSERT_EQ(-1, landlock_restrict_self(-1, 0));
217 ASSERT_EQ(EPERM, errno);
218 ASSERT_EQ(-1, landlock_restrict_self(ruleset_fd, 0));
219 ASSERT_EQ(EPERM, errno);
220
221 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
222
223 /* Checks invalid flags. */
224 ASSERT_EQ(-1, landlock_restrict_self(-1, -1));
225 ASSERT_EQ(EINVAL, errno);
226
227 /* Checks invalid ruleset FD. */
228 ASSERT_EQ(-1, landlock_restrict_self(-1, 0));
229 ASSERT_EQ(EBADF, errno);
230
231 /* Checks valid call. */
232 ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0));
233 ASSERT_EQ(0, close(ruleset_fd));
234 }
235
TEST(ruleset_fd_io)236 TEST(ruleset_fd_io)
237 {
238 struct landlock_ruleset_attr ruleset_attr = {
239 .handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
240 };
241 int ruleset_fd;
242 char buf;
243
244 drop_caps(_metadata);
245 ruleset_fd =
246 landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
247 ASSERT_LE(0, ruleset_fd);
248
249 ASSERT_EQ(-1, write(ruleset_fd, ".", 1));
250 ASSERT_EQ(EINVAL, errno);
251 ASSERT_EQ(-1, read(ruleset_fd, &buf, 1));
252 ASSERT_EQ(EINVAL, errno);
253
254 ASSERT_EQ(0, close(ruleset_fd));
255 }
256
257 /* Tests enforcement of a ruleset FD transferred through a UNIX socket. */
TEST(ruleset_fd_transfer)258 TEST(ruleset_fd_transfer)
259 {
260 struct landlock_ruleset_attr ruleset_attr = {
261 .handled_access_fs = LANDLOCK_ACCESS_FS_READ_DIR,
262 };
263 struct landlock_path_beneath_attr path_beneath_attr = {
264 .allowed_access = LANDLOCK_ACCESS_FS_READ_DIR,
265 };
266 int ruleset_fd_tx, dir_fd;
267 int socket_fds[2];
268 pid_t child;
269 int status;
270
271 drop_caps(_metadata);
272
273 /* Creates a test ruleset with a simple rule. */
274 ruleset_fd_tx =
275 landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
276 ASSERT_LE(0, ruleset_fd_tx);
277 path_beneath_attr.parent_fd =
278 open("/tmp", O_PATH | O_NOFOLLOW | O_DIRECTORY | O_CLOEXEC);
279 ASSERT_LE(0, path_beneath_attr.parent_fd);
280 ASSERT_EQ(0,
281 landlock_add_rule(ruleset_fd_tx, LANDLOCK_RULE_PATH_BENEATH,
282 &path_beneath_attr, 0));
283 ASSERT_EQ(0, close(path_beneath_attr.parent_fd));
284
285 /* Sends the ruleset FD over a socketpair and then close it. */
286 ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0,
287 socket_fds));
288 ASSERT_EQ(0, send_fd(socket_fds[0], ruleset_fd_tx));
289 ASSERT_EQ(0, close(socket_fds[0]));
290 ASSERT_EQ(0, close(ruleset_fd_tx));
291
292 child = fork();
293 ASSERT_LE(0, child);
294 if (child == 0) {
295 const int ruleset_fd_rx = recv_fd(socket_fds[1]);
296
297 ASSERT_LE(0, ruleset_fd_rx);
298 ASSERT_EQ(0, close(socket_fds[1]));
299
300 /* Enforces the received ruleset on the child. */
301 ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
302 ASSERT_EQ(0, landlock_restrict_self(ruleset_fd_rx, 0));
303 ASSERT_EQ(0, close(ruleset_fd_rx));
304
305 /* Checks that the ruleset enforcement. */
306 ASSERT_EQ(-1, open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC));
307 ASSERT_EQ(EACCES, errno);
308 dir_fd = open("/tmp", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
309 ASSERT_LE(0, dir_fd);
310 ASSERT_EQ(0, close(dir_fd));
311 _exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE);
312 return;
313 }
314
315 ASSERT_EQ(0, close(socket_fds[1]));
316
317 /* Checks that the parent is unrestricted. */
318 dir_fd = open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
319 ASSERT_LE(0, dir_fd);
320 ASSERT_EQ(0, close(dir_fd));
321 dir_fd = open("/tmp", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
322 ASSERT_LE(0, dir_fd);
323 ASSERT_EQ(0, close(dir_fd));
324
325 ASSERT_EQ(child, waitpid(child, &status, 0));
326 ASSERT_EQ(1, WIFEXITED(status));
327 ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status));
328 }
329
TEST(cred_transfer)330 TEST(cred_transfer)
331 {
332 struct landlock_ruleset_attr ruleset_attr = {
333 .handled_access_fs = LANDLOCK_ACCESS_FS_READ_DIR,
334 };
335 int ruleset_fd, dir_fd;
336 pid_t child;
337 int status;
338
339 drop_caps(_metadata);
340
341 dir_fd = open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
342 EXPECT_LE(0, dir_fd);
343 EXPECT_EQ(0, close(dir_fd));
344
345 /* Denies opening directories. */
346 ruleset_fd =
347 landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
348 ASSERT_LE(0, ruleset_fd);
349 EXPECT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
350 ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0));
351 EXPECT_EQ(0, close(ruleset_fd));
352
353 /* Checks ruleset enforcement. */
354 EXPECT_EQ(-1, open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC));
355 EXPECT_EQ(EACCES, errno);
356
357 /* Needed for KEYCTL_SESSION_TO_PARENT permission checks */
358 EXPECT_NE(-1, syscall(__NR_keyctl, KEYCTL_JOIN_SESSION_KEYRING, NULL, 0,
359 0, 0))
360 {
361 TH_LOG("Failed to join session keyring: %s", strerror(errno));
362 }
363
364 child = fork();
365 ASSERT_LE(0, child);
366 if (child == 0) {
367 /* Checks ruleset enforcement. */
368 EXPECT_EQ(-1, open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC));
369 EXPECT_EQ(EACCES, errno);
370
371 /*
372 * KEYCTL_SESSION_TO_PARENT is a no-op unless we have a
373 * different session keyring in the child, so make that happen.
374 */
375 EXPECT_NE(-1, syscall(__NR_keyctl, KEYCTL_JOIN_SESSION_KEYRING,
376 NULL, 0, 0, 0));
377
378 /*
379 * KEYCTL_SESSION_TO_PARENT installs credentials on the parent
380 * that never go through the cred_prepare hook, this path uses
381 * cred_transfer instead.
382 */
383 EXPECT_EQ(0, syscall(__NR_keyctl, KEYCTL_SESSION_TO_PARENT, 0,
384 0, 0, 0));
385
386 /* Re-checks ruleset enforcement. */
387 EXPECT_EQ(-1, open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC));
388 EXPECT_EQ(EACCES, errno);
389
390 _exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE);
391 return;
392 }
393
394 EXPECT_EQ(child, waitpid(child, &status, 0));
395 EXPECT_EQ(1, WIFEXITED(status));
396 EXPECT_EQ(EXIT_SUCCESS, WEXITSTATUS(status));
397
398 /* Re-checks ruleset enforcement. */
399 EXPECT_EQ(-1, open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC));
400 EXPECT_EQ(EACCES, errno);
401 }
402
403 TEST_HARNESS_MAIN
404