Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1#define _GNU_SOURCE
2
3#include <cap-ng.h>
4#include <linux/capability.h>
5#include <stdbool.h>
6#include <string.h>
7#include <stdio.h>
8#include <fcntl.h>
9#include <errno.h>
10#include <stdarg.h>
11#include <sched.h>
12#include <sys/mount.h>
13#include <limits.h>
14#include <libgen.h>
15#include <malloc.h>
16#include <sys/wait.h>
17#include <sys/prctl.h>
18#include <sys/stat.h>
19
20#include "../kselftest.h"
21
22#ifndef PR_CAP_AMBIENT
23#define PR_CAP_AMBIENT 47
24# define PR_CAP_AMBIENT_IS_SET 1
25# define PR_CAP_AMBIENT_RAISE 2
26# define PR_CAP_AMBIENT_LOWER 3
27# define PR_CAP_AMBIENT_CLEAR_ALL 4
28#endif
29
30static int nerrs;
31static pid_t mpid; /* main() pid is used to avoid duplicate test counts */
32
33static void vmaybe_write_file(bool enoent_ok, char *filename, char *fmt, va_list ap)
34{
35 char buf[4096];
36 int fd;
37 ssize_t written;
38 int buf_len;
39
40 buf_len = vsnprintf(buf, sizeof(buf), fmt, ap);
41 if (buf_len < 0)
42 ksft_exit_fail_msg("vsnprintf failed - %s\n", strerror(errno));
43
44 if (buf_len >= sizeof(buf))
45 ksft_exit_fail_msg("vsnprintf output truncated\n");
46
47
48 fd = open(filename, O_WRONLY);
49 if (fd < 0) {
50 if ((errno == ENOENT) && enoent_ok)
51 return;
52 ksft_exit_fail_msg("open of %s failed - %s\n",
53 filename, strerror(errno));
54 }
55 written = write(fd, buf, buf_len);
56 if (written != buf_len) {
57 if (written >= 0) {
58 ksft_exit_fail_msg("short write to %s\n", filename);
59 } else {
60 ksft_exit_fail_msg("write to %s failed - %s\n",
61 filename, strerror(errno));
62 }
63 }
64 if (close(fd) != 0) {
65 ksft_exit_fail_msg("close of %s failed - %s\n",
66 filename, strerror(errno));
67 }
68}
69
70static void maybe_write_file(char *filename, char *fmt, ...)
71{
72 va_list ap;
73
74 va_start(ap, fmt);
75 vmaybe_write_file(true, filename, fmt, ap);
76 va_end(ap);
77}
78
79static void write_file(char *filename, char *fmt, ...)
80{
81 va_list ap;
82
83 va_start(ap, fmt);
84 vmaybe_write_file(false, filename, fmt, ap);
85 va_end(ap);
86}
87
88static bool create_and_enter_ns(uid_t inner_uid)
89{
90 uid_t outer_uid;
91 gid_t outer_gid;
92 int i;
93 bool have_outer_privilege;
94
95 outer_uid = getuid();
96 outer_gid = getgid();
97
98 /*
99 * TODO: If we're already root, we could skip creating the userns.
100 */
101
102 if (unshare(CLONE_NEWNS) == 0) {
103 ksft_print_msg("[NOTE]\tUsing global UIDs for tests\n");
104 if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) != 0)
105 ksft_exit_fail_msg("PR_SET_KEEPCAPS - %s\n",
106 strerror(errno));
107 if (setresuid(inner_uid, inner_uid, -1) != 0)
108 ksft_exit_fail_msg("setresuid - %s\n", strerror(errno));
109
110 // Re-enable effective caps
111 capng_get_caps_process();
112 for (i = 0; i < CAP_LAST_CAP; i++)
113 if (capng_have_capability(CAPNG_PERMITTED, i))
114 capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, i);
115 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
116 ksft_exit_fail_msg(
117 "capng_apply - %s\n", strerror(errno));
118
119 have_outer_privilege = true;
120 } else if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == 0) {
121 ksft_print_msg("[NOTE]\tUsing a user namespace for tests\n");
122 maybe_write_file("/proc/self/setgroups", "deny");
123 write_file("/proc/self/uid_map", "%d %d 1", inner_uid, outer_uid);
124 write_file("/proc/self/gid_map", "0 %d 1", outer_gid);
125
126 have_outer_privilege = false;
127 } else {
128 ksft_exit_skip("must be root or be able to create a userns\n");
129 }
130
131 if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL) != 0)
132 ksft_exit_fail_msg("remount everything private - %s\n",
133 strerror(errno));
134
135 return have_outer_privilege;
136}
137
138static void chdir_to_tmpfs(void)
139{
140 char cwd[PATH_MAX];
141 if (getcwd(cwd, sizeof(cwd)) != cwd)
142 ksft_exit_fail_msg("getcwd - %s\n", strerror(errno));
143
144 if (mount("private_tmp", ".", "tmpfs", 0, "mode=0777") != 0)
145 ksft_exit_fail_msg("mount private tmpfs - %s\n",
146 strerror(errno));
147
148 if (chdir(cwd) != 0)
149 ksft_exit_fail_msg("chdir to private tmpfs - %s\n",
150 strerror(errno));
151}
152
153static void copy_fromat_to(int fromfd, const char *fromname, const char *toname)
154{
155 int from = openat(fromfd, fromname, O_RDONLY);
156 if (from == -1)
157 ksft_exit_fail_msg("open copy source - %s\n", strerror(errno));
158
159 int to = open(toname, O_CREAT | O_WRONLY | O_EXCL, 0700);
160
161 while (true) {
162 char buf[4096];
163 ssize_t sz = read(from, buf, sizeof(buf));
164 if (sz == 0)
165 break;
166 if (sz < 0)
167 ksft_exit_fail_msg("read - %s\n", strerror(errno));
168
169 if (write(to, buf, sz) != sz)
170 /* no short writes on tmpfs */
171 ksft_exit_fail_msg("write - %s\n", strerror(errno));
172 }
173
174 close(from);
175 close(to);
176}
177
178static bool fork_wait(void)
179{
180 pid_t child = fork();
181 if (child == 0) {
182 nerrs = 0;
183 return true;
184 } else if (child > 0) {
185 int status;
186 if (waitpid(child, &status, 0) != child ||
187 !WIFEXITED(status)) {
188 ksft_print_msg("Child died\n");
189 nerrs++;
190 } else if (WEXITSTATUS(status) != 0) {
191 ksft_print_msg("Child failed\n");
192 nerrs++;
193 } else {
194 /* don't print this message for mpid */
195 if (getpid() != mpid)
196 ksft_test_result_pass("Passed\n");
197 }
198 return false;
199 } else {
200 ksft_exit_fail_msg("fork - %s\n", strerror(errno));
201 return false;
202 }
203}
204
205static void exec_other_validate_cap(const char *name,
206 bool eff, bool perm, bool inh, bool ambient)
207{
208 execl(name, name, (eff ? "1" : "0"),
209 (perm ? "1" : "0"), (inh ? "1" : "0"), (ambient ? "1" : "0"),
210 NULL);
211 ksft_exit_fail_msg("execl - %s\n", strerror(errno));
212}
213
214static void exec_validate_cap(bool eff, bool perm, bool inh, bool ambient)
215{
216 exec_other_validate_cap("./validate_cap", eff, perm, inh, ambient);
217}
218
219static int do_tests(int uid, const char *our_path)
220{
221 bool have_outer_privilege = create_and_enter_ns(uid);
222
223 int ourpath_fd = open(our_path, O_RDONLY | O_DIRECTORY);
224 if (ourpath_fd == -1)
225 ksft_exit_fail_msg("open '%s' - %s\n",
226 our_path, strerror(errno));
227
228 chdir_to_tmpfs();
229
230 copy_fromat_to(ourpath_fd, "validate_cap", "validate_cap");
231
232 if (have_outer_privilege) {
233 uid_t gid = getegid();
234
235 copy_fromat_to(ourpath_fd, "validate_cap",
236 "validate_cap_suidroot");
237 if (chown("validate_cap_suidroot", 0, -1) != 0)
238 ksft_exit_fail_msg("chown - %s\n", strerror(errno));
239 if (chmod("validate_cap_suidroot", S_ISUID | 0700) != 0)
240 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
241
242 copy_fromat_to(ourpath_fd, "validate_cap",
243 "validate_cap_suidnonroot");
244 if (chown("validate_cap_suidnonroot", uid + 1, -1) != 0)
245 ksft_exit_fail_msg("chown - %s\n", strerror(errno));
246 if (chmod("validate_cap_suidnonroot", S_ISUID | 0700) != 0)
247 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
248
249 copy_fromat_to(ourpath_fd, "validate_cap",
250 "validate_cap_sgidroot");
251 if (chown("validate_cap_sgidroot", -1, 0) != 0)
252 ksft_exit_fail_msg("chown - %s\n", strerror(errno));
253 if (chmod("validate_cap_sgidroot", S_ISGID | 0710) != 0)
254 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
255
256 copy_fromat_to(ourpath_fd, "validate_cap",
257 "validate_cap_sgidnonroot");
258 if (chown("validate_cap_sgidnonroot", -1, gid + 1) != 0)
259 ksft_exit_fail_msg("chown - %s\n", strerror(errno));
260 if (chmod("validate_cap_sgidnonroot", S_ISGID | 0710) != 0)
261 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
262 }
263
264 capng_get_caps_process();
265
266 /* Make sure that i starts out clear */
267 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
268 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
269 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
270
271 if (uid == 0) {
272 ksft_print_msg("[RUN]\tRoot => ep\n");
273 if (fork_wait())
274 exec_validate_cap(true, true, false, false);
275 } else {
276 ksft_print_msg("[RUN]\tNon-root => no caps\n");
277 if (fork_wait())
278 exec_validate_cap(false, false, false, false);
279 }
280
281 ksft_print_msg("Check cap_ambient manipulation rules\n");
282
283 /* We should not be able to add ambient caps yet. */
284 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != -1 || errno != EPERM) {
285 if (errno == EINVAL)
286 ksft_test_result_fail(
287 "PR_CAP_AMBIENT_RAISE isn't supported\n");
288 else
289 ksft_test_result_fail(
290 "PR_CAP_AMBIENT_RAISE should have failed eith EPERM on a non-inheritable cap\n");
291 return 1;
292 }
293 ksft_test_result_pass(
294 "PR_CAP_AMBIENT_RAISE failed on non-inheritable cap\n");
295
296 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_RAW);
297 capng_update(CAPNG_DROP, CAPNG_PERMITTED, CAP_NET_RAW);
298 capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_NET_RAW);
299 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
300 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
301 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_RAW, 0, 0, 0) != -1 || errno != EPERM) {
302 ksft_test_result_fail(
303 "PR_CAP_AMBIENT_RAISE should have failed on a non-permitted cap\n");
304 return 1;
305 }
306 ksft_test_result_pass(
307 "PR_CAP_AMBIENT_RAISE failed on non-permitted cap\n");
308
309 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
310 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
311 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
312 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
313 ksft_test_result_fail(
314 "PR_CAP_AMBIENT_RAISE should have succeeded\n");
315 return 1;
316 }
317 ksft_test_result_pass("PR_CAP_AMBIENT_RAISE worked\n");
318
319 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 1) {
320 ksft_test_result_fail("PR_CAP_AMBIENT_IS_SET is broken\n");
321 return 1;
322 }
323
324 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0, 0, 0, 0) != 0)
325 ksft_exit_fail_msg("PR_CAP_AMBIENT_CLEAR_ALL - %s\n",
326 strerror(errno));
327
328 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
329 ksft_test_result_fail(
330 "PR_CAP_AMBIENT_CLEAR_ALL didn't work\n");
331 return 1;
332 }
333
334 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)
335 ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n",
336 strerror(errno));
337
338 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
339 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
340 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
341
342 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
343 ksft_test_result_fail("Dropping I should have dropped A\n");
344 return 1;
345 }
346
347 ksft_test_result_pass("Basic manipulation appears to work\n");
348
349 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
350 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
351 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
352 if (uid == 0) {
353 ksft_print_msg("[RUN]\tRoot +i => eip\n");
354 if (fork_wait())
355 exec_validate_cap(true, true, true, false);
356 } else {
357 ksft_print_msg("[RUN]\tNon-root +i => i\n");
358 if (fork_wait())
359 exec_validate_cap(false, false, true, false);
360 }
361
362 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)
363 ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n",
364 strerror(errno));
365
366 ksft_print_msg("[RUN]\tUID %d +ia => eipa\n", uid);
367 if (fork_wait())
368 exec_validate_cap(true, true, true, true);
369
370 /* The remaining tests need real privilege */
371
372 if (!have_outer_privilege) {
373 ksft_test_result_skip("SUID/SGID tests (needs privilege)\n");
374 goto done;
375 }
376
377 if (uid == 0) {
378 ksft_print_msg("[RUN]\tRoot +ia, suidroot => eipa\n");
379 if (fork_wait())
380 exec_other_validate_cap("./validate_cap_suidroot",
381 true, true, true, true);
382
383 ksft_print_msg("[RUN]\tRoot +ia, suidnonroot => ip\n");
384 if (fork_wait())
385 exec_other_validate_cap("./validate_cap_suidnonroot",
386 false, true, true, false);
387
388 ksft_print_msg("[RUN]\tRoot +ia, sgidroot => eipa\n");
389 if (fork_wait())
390 exec_other_validate_cap("./validate_cap_sgidroot",
391 true, true, true, true);
392
393 if (fork_wait()) {
394 ksft_print_msg(
395 "[RUN]\tRoot, gid != 0, +ia, sgidroot => eip\n");
396 if (setresgid(1, 1, 1) != 0)
397 ksft_exit_fail_msg("setresgid - %s\n",
398 strerror(errno));
399 exec_other_validate_cap("./validate_cap_sgidroot",
400 true, true, true, false);
401 }
402
403 ksft_print_msg("[RUN]\tRoot +ia, sgidnonroot => eip\n");
404 if (fork_wait())
405 exec_other_validate_cap("./validate_cap_sgidnonroot",
406 true, true, true, false);
407 } else {
408 ksft_print_msg("[RUN]\tNon-root +ia, sgidnonroot => i\n");
409 if (fork_wait())
410 exec_other_validate_cap("./validate_cap_sgidnonroot",
411 false, false, true, false);
412
413 if (fork_wait()) {
414 ksft_print_msg("[RUN]\tNon-root +ia, sgidroot => i\n");
415 if (setresgid(1, 1, 1) != 0)
416 ksft_exit_fail_msg("setresgid - %s\n",
417 strerror(errno));
418 exec_other_validate_cap("./validate_cap_sgidroot",
419 false, false, true, false);
420 }
421 }
422
423done:
424 ksft_print_cnts();
425 return nerrs ? 1 : 0;
426}
427
428int main(int argc, char **argv)
429{
430 char *tmp1, *tmp2, *our_path;
431
432 ksft_print_header();
433
434 /* Find our path */
435 tmp1 = strdup(argv[0]);
436 if (!tmp1)
437 ksft_exit_fail_msg("strdup - %s\n", strerror(errno));
438 tmp2 = dirname(tmp1);
439 our_path = strdup(tmp2);
440 if (!our_path)
441 ksft_exit_fail_msg("strdup - %s\n", strerror(errno));
442 free(tmp1);
443
444 mpid = getpid();
445
446 if (fork_wait()) {
447 ksft_print_msg("[RUN]\t+++ Tests with uid == 0 +++\n");
448 return do_tests(0, our_path);
449 }
450
451 ksft_print_msg("==================================================\n");
452
453 if (fork_wait()) {
454 ksft_print_msg("[RUN]\t+++ Tests with uid != 0 +++\n");
455 return do_tests(1, our_path);
456 }
457
458 return nerrs ? 1 : 0;
459}