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