1// SPDX-License-Identifier: GPL-2.0
2#define _GNU_SOURCE
3
4#include <cap-ng.h>
5#include <linux/capability.h>
6#include <stdbool.h>
7#include <string.h>
8#include <stdio.h>
9#include <fcntl.h>
10#include <errno.h>
11#include <stdarg.h>
12#include <sched.h>
13#include <sys/mount.h>
14#include <limits.h>
15#include <libgen.h>
16#include <malloc.h>
17#include <sys/wait.h>
18#include <sys/prctl.h>
19#include <sys/stat.h>
20
21#include "../kselftest.h"
22
23static int nerrs;
24static pid_t mpid; /* main() pid is used to avoid duplicate test counts */
25
26static void vmaybe_write_file(bool enoent_ok, char *filename, char *fmt, va_list ap)
27{
28 char buf[4096];
29 int fd;
30 ssize_t written;
31 int buf_len;
32
33 buf_len = vsnprintf(buf, sizeof(buf), fmt, ap);
34 if (buf_len < 0)
35 ksft_exit_fail_msg(msg: "vsnprintf failed - %s\n", strerror(errno));
36
37 if (buf_len >= sizeof(buf))
38 ksft_exit_fail_msg(msg: "vsnprintf output truncated\n");
39
40
41 fd = open(filename, O_WRONLY);
42 if (fd < 0) {
43 if ((errno == ENOENT) && enoent_ok)
44 return;
45 ksft_exit_fail_msg(msg: "open of %s failed - %s\n",
46 filename, strerror(errno));
47 }
48 written = write(fd, buf, buf_len);
49 if (written != buf_len) {
50 if (written >= 0) {
51 ksft_exit_fail_msg(msg: "short write to %s\n", filename);
52 } else {
53 ksft_exit_fail_msg(msg: "write to %s failed - %s\n",
54 filename, strerror(errno));
55 }
56 }
57 if (close(fd) != 0) {
58 ksft_exit_fail_msg(msg: "close of %s failed - %s\n",
59 filename, strerror(errno));
60 }
61}
62
63static void maybe_write_file(char *filename, char *fmt, ...)
64{
65 va_list ap;
66
67 va_start(ap, fmt);
68 vmaybe_write_file(true, filename, fmt, ap);
69 va_end(ap);
70}
71
72static void write_file(char *filename, char *fmt, ...)
73{
74 va_list ap;
75
76 va_start(ap, fmt);
77 vmaybe_write_file(false, filename, fmt, ap);
78 va_end(ap);
79}
80
81static bool create_and_enter_ns(uid_t inner_uid)
82{
83 uid_t outer_uid;
84 gid_t outer_gid;
85 int i;
86 bool have_outer_privilege;
87
88 outer_uid = getuid();
89 outer_gid = getgid();
90
91 /*
92 * TODO: If we're already root, we could skip creating the userns.
93 */
94
95 if (unshare(CLONE_NEWNS) == 0) {
96 ksft_print_msg(msg: "[NOTE]\tUsing global UIDs for tests\n");
97 if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) != 0)
98 ksft_exit_fail_msg(msg: "PR_SET_KEEPCAPS - %s\n",
99 strerror(errno));
100 if (setresuid(inner_uid, inner_uid, -1) != 0)
101 ksft_exit_fail_msg(msg: "setresuid - %s\n", strerror(errno));
102
103 // Re-enable effective caps
104 capng_get_caps_process();
105 for (i = 0; i < CAP_LAST_CAP; i++)
106 if (capng_have_capability(CAPNG_PERMITTED, i))
107 capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, i);
108 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
109 ksft_exit_fail_msg(
110 msg: "capng_apply - %s\n", strerror(errno));
111
112 have_outer_privilege = true;
113 } else if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == 0) {
114 ksft_print_msg(msg: "[NOTE]\tUsing a user namespace for tests\n");
115 maybe_write_file(filename: "/proc/self/setgroups", fmt: "deny");
116 write_file(filename: "/proc/self/uid_map", fmt: "%d %d 1", inner_uid, outer_uid);
117 write_file(filename: "/proc/self/gid_map", fmt: "0 %d 1", outer_gid);
118
119 have_outer_privilege = false;
120 } else {
121 ksft_exit_skip(msg: "must be root or be able to create a userns\n");
122 }
123
124 if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL) != 0)
125 ksft_exit_fail_msg(msg: "remount everything private - %s\n",
126 strerror(errno));
127
128 return have_outer_privilege;
129}
130
131static void chdir_to_tmpfs(void)
132{
133 char cwd[PATH_MAX];
134 if (getcwd(cwd, sizeof(cwd)) != cwd)
135 ksft_exit_fail_msg(msg: "getcwd - %s\n", strerror(errno));
136
137 if (mount("private_tmp", ".", "tmpfs", 0, "mode=0777") != 0)
138 ksft_exit_fail_msg(msg: "mount private tmpfs - %s\n",
139 strerror(errno));
140
141 if (chdir(cwd) != 0)
142 ksft_exit_fail_msg(msg: "chdir to private tmpfs - %s\n",
143 strerror(errno));
144}
145
146static void copy_fromat_to(int fromfd, const char *fromname, const char *toname)
147{
148 int from = openat(fromfd, fromname, O_RDONLY);
149 if (from == -1)
150 ksft_exit_fail_msg("open copy source - %s\n", strerror(errno));
151
152 int to = open(toname, O_CREAT | O_WRONLY | O_EXCL, 0700);
153
154 while (true) {
155 char buf[4096];
156 ssize_t sz = read(from, buf, sizeof(buf));
157 if (sz == 0)
158 break;
159 if (sz < 0)
160 ksft_exit_fail_msg("read - %s\n", strerror(errno));
161
162 if (write(to, buf, sz) != sz)
163 /* no short writes on tmpfs */
164 ksft_exit_fail_msg("write - %s\n", strerror(errno));
165 }
166
167 close(from);
168 close(to);
169}
170
171static bool fork_wait(void)
172{
173 pid_t child = fork();
174 if (child == 0) {
175 nerrs = 0;
176 return true;
177 } else if (child > 0) {
178 int status;
179 if (waitpid(child, &status, 0) != child ||
180 !WIFEXITED(status)) {
181 ksft_print_msg(msg: "Child died\n");
182 nerrs++;
183 } else if (WEXITSTATUS(status) != 0) {
184 ksft_print_msg(msg: "Child failed\n");
185 nerrs++;
186 } else {
187 /* don't print this message for mpid */
188 if (getpid() != mpid)
189 ksft_test_result_pass(msg: "Passed\n");
190 }
191 return false;
192 } else {
193 ksft_exit_fail_msg("fork - %s\n", strerror(errno));
194 return false;
195 }
196}
197
198static void exec_other_validate_cap(const char *name,
199 bool eff, bool perm, bool inh, bool ambient)
200{
201 execl(name, name, (eff ? "1" : "0"),
202 (perm ? "1" : "0"), (inh ? "1" : "0"), (ambient ? "1" : "0"),
203 NULL);
204 ksft_exit_fail_msg("execl - %s\n", strerror(errno));
205}
206
207static void exec_validate_cap(bool eff, bool perm, bool inh, bool ambient)
208{
209 exec_other_validate_cap(name: "./validate_cap", eff, perm, inh, ambient);
210}
211
212static int do_tests(int uid, const char *our_path)
213{
214 bool have_outer_privilege = create_and_enter_ns(inner_uid: uid);
215
216 int ourpath_fd = open(our_path, O_RDONLY | O_DIRECTORY);
217 if (ourpath_fd == -1)
218 ksft_exit_fail_msg("open '%s' - %s\n",
219 our_path, strerror(errno));
220
221 chdir_to_tmpfs();
222
223 copy_fromat_to(fromfd: ourpath_fd, fromname: "validate_cap", toname: "validate_cap");
224
225 if (have_outer_privilege) {
226 uid_t gid = getegid();
227
228 copy_fromat_to(fromfd: ourpath_fd, fromname: "validate_cap",
229 toname: "validate_cap_suidroot");
230 if (chown("validate_cap_suidroot", 0, -1) != 0)
231 ksft_exit_fail_msg("chown - %s\n", strerror(errno));
232 if (chmod("validate_cap_suidroot", S_ISUID | 0700) != 0)
233 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
234
235 copy_fromat_to(fromfd: ourpath_fd, fromname: "validate_cap",
236 toname: "validate_cap_suidnonroot");
237 if (chown("validate_cap_suidnonroot", uid + 1, -1) != 0)
238 ksft_exit_fail_msg("chown - %s\n", strerror(errno));
239 if (chmod("validate_cap_suidnonroot", S_ISUID | 0700) != 0)
240 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
241
242 copy_fromat_to(fromfd: ourpath_fd, fromname: "validate_cap",
243 toname: "validate_cap_sgidroot");
244 if (chown("validate_cap_sgidroot", -1, 0) != 0)
245 ksft_exit_fail_msg("chown - %s\n", strerror(errno));
246 if (chmod("validate_cap_sgidroot", S_ISGID | 0710) != 0)
247 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
248
249 copy_fromat_to(fromfd: ourpath_fd, fromname: "validate_cap",
250 toname: "validate_cap_sgidnonroot");
251 if (chown("validate_cap_sgidnonroot", -1, gid + 1) != 0)
252 ksft_exit_fail_msg("chown - %s\n", strerror(errno));
253 if (chmod("validate_cap_sgidnonroot", S_ISGID | 0710) != 0)
254 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
255 }
256
257 capng_get_caps_process();
258
259 /* Make sure that i starts out clear */
260 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
261 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
262 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
263
264 if (uid == 0) {
265 ksft_print_msg(msg: "[RUN]\tRoot => ep\n");
266 if (fork_wait())
267 exec_validate_cap(eff: true, perm: true, inh: false, ambient: false);
268 } else {
269 ksft_print_msg(msg: "[RUN]\tNon-root => no caps\n");
270 if (fork_wait())
271 exec_validate_cap(eff: false, perm: false, inh: false, ambient: false);
272 }
273
274 ksft_print_msg(msg: "Check cap_ambient manipulation rules\n");
275
276 /* We should not be able to add ambient caps yet. */
277 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != -1 || errno != EPERM) {
278 if (errno == EINVAL)
279 ksft_test_result_fail(
280 msg: "PR_CAP_AMBIENT_RAISE isn't supported\n");
281 else
282 ksft_test_result_fail(
283 msg: "PR_CAP_AMBIENT_RAISE should have failed eith EPERM on a non-inheritable cap\n");
284 return 1;
285 }
286 ksft_test_result_pass(
287 msg: "PR_CAP_AMBIENT_RAISE failed on non-inheritable cap\n");
288
289 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_RAW);
290 capng_update(CAPNG_DROP, CAPNG_PERMITTED, CAP_NET_RAW);
291 capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_NET_RAW);
292 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
293 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
294 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_RAW, 0, 0, 0) != -1 || errno != EPERM) {
295 ksft_test_result_fail(
296 msg: "PR_CAP_AMBIENT_RAISE should have failed on a non-permitted cap\n");
297 return 1;
298 }
299 ksft_test_result_pass(
300 msg: "PR_CAP_AMBIENT_RAISE failed on non-permitted cap\n");
301
302 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
303 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
304 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
305 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
306 ksft_test_result_fail(
307 msg: "PR_CAP_AMBIENT_RAISE should have succeeded\n");
308 return 1;
309 }
310 ksft_test_result_pass(msg: "PR_CAP_AMBIENT_RAISE worked\n");
311
312 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 1) {
313 ksft_test_result_fail(msg: "PR_CAP_AMBIENT_IS_SET is broken\n");
314 return 1;
315 }
316
317 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0, 0, 0, 0) != 0)
318 ksft_exit_fail_msg("PR_CAP_AMBIENT_CLEAR_ALL - %s\n",
319 strerror(errno));
320
321 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
322 ksft_test_result_fail(
323 msg: "PR_CAP_AMBIENT_CLEAR_ALL didn't work\n");
324 return 1;
325 }
326
327 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)
328 ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n",
329 strerror(errno));
330
331 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
332 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
333 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
334
335 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
336 ksft_test_result_fail(msg: "Dropping I should have dropped A\n");
337 return 1;
338 }
339
340 ksft_test_result_pass(msg: "Basic manipulation appears to work\n");
341
342 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
343 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
344 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
345 if (uid == 0) {
346 ksft_print_msg(msg: "[RUN]\tRoot +i => eip\n");
347 if (fork_wait())
348 exec_validate_cap(eff: true, perm: true, inh: true, ambient: false);
349 } else {
350 ksft_print_msg(msg: "[RUN]\tNon-root +i => i\n");
351 if (fork_wait())
352 exec_validate_cap(eff: false, perm: false, inh: true, ambient: false);
353 }
354
355 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)
356 ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n",
357 strerror(errno));
358
359 ksft_print_msg(msg: "[RUN]\tUID %d +ia => eipa\n", uid);
360 if (fork_wait())
361 exec_validate_cap(eff: true, perm: true, inh: true, ambient: true);
362
363 /* The remaining tests need real privilege */
364
365 if (!have_outer_privilege) {
366 ksft_test_result_skip(msg: "SUID/SGID tests (needs privilege)\n");
367 goto done;
368 }
369
370 if (uid == 0) {
371 ksft_print_msg(msg: "[RUN]\tRoot +ia, suidroot => eipa\n");
372 if (fork_wait())
373 exec_other_validate_cap(name: "./validate_cap_suidroot",
374 eff: true, perm: true, inh: true, ambient: true);
375
376 ksft_print_msg(msg: "[RUN]\tRoot +ia, suidnonroot => ip\n");
377 if (fork_wait())
378 exec_other_validate_cap(name: "./validate_cap_suidnonroot",
379 eff: false, perm: true, inh: true, ambient: false);
380
381 ksft_print_msg(msg: "[RUN]\tRoot +ia, sgidroot => eipa\n");
382 if (fork_wait())
383 exec_other_validate_cap(name: "./validate_cap_sgidroot",
384 eff: true, perm: true, inh: true, ambient: true);
385
386 if (fork_wait()) {
387 ksft_print_msg(
388 msg: "[RUN]\tRoot, gid != 0, +ia, sgidroot => eip\n");
389 if (setresgid(1, 1, 1) != 0)
390 ksft_exit_fail_msg("setresgid - %s\n",
391 strerror(errno));
392 exec_other_validate_cap(name: "./validate_cap_sgidroot",
393 eff: true, perm: true, inh: true, ambient: false);
394 }
395
396 ksft_print_msg(msg: "[RUN]\tRoot +ia, sgidnonroot => eip\n");
397 if (fork_wait())
398 exec_other_validate_cap(name: "./validate_cap_sgidnonroot",
399 eff: true, perm: true, inh: true, ambient: false);
400 } else {
401 ksft_print_msg(msg: "[RUN]\tNon-root +ia, sgidnonroot => i\n");
402 if (fork_wait())
403 exec_other_validate_cap(name: "./validate_cap_sgidnonroot",
404 eff: false, perm: false, inh: true, ambient: false);
405
406 if (fork_wait()) {
407 ksft_print_msg(msg: "[RUN]\tNon-root +ia, sgidroot => i\n");
408 if (setresgid(1, 1, 1) != 0)
409 ksft_exit_fail_msg("setresgid - %s\n",
410 strerror(errno));
411 exec_other_validate_cap(name: "./validate_cap_sgidroot",
412 eff: false, perm: false, inh: true, ambient: false);
413 }
414 }
415
416done:
417 ksft_print_cnts();
418 return nerrs ? 1 : 0;
419}
420
421int main(int argc, char **argv)
422{
423 char *tmp1, *tmp2, *our_path;
424
425 /* Find our path */
426 tmp1 = strdup(argv[0]);
427 if (!tmp1)
428 ksft_exit_fail_msg("strdup - %s\n", strerror(errno));
429 tmp2 = dirname(tmp1);
430 our_path = strdup(tmp2);
431 if (!our_path)
432 ksft_exit_fail_msg("strdup - %s\n", strerror(errno));
433 free(tmp1);
434
435 mpid = getpid();
436
437 if (fork_wait()) {
438 ksft_print_header();
439 ksft_set_plan(plan: 12);
440 ksft_print_msg(msg: "[RUN]\t+++ Tests with uid == 0 +++\n");
441 return do_tests(uid: 0, our_path);
442 }
443
444 ksft_print_msg(msg: "==================================================\n");
445
446 if (fork_wait()) {
447 ksft_print_header();
448 ksft_set_plan(plan: 9);
449 ksft_print_msg(msg: "[RUN]\t+++ Tests with uid != 0 +++\n");
450 return do_tests(uid: 1, our_path);
451 }
452
453 return nerrs ? 1 : 0;
454}
455

source code of linux/tools/testing/selftests/capabilities/test_execve.c