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 | /* |
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 | |
131 | static 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 | |
146 | static 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 | |
171 | static 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 | |
198 | static 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 | |
207 | static 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 | |
212 | static 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 | |
416 | done: |
417 | ksft_print_cnts(); |
418 | return nerrs ? 1 : 0; |
419 | } |
420 | |
421 | int 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 | |