5 #include <linux/capability.h>
13 #include <sys/mount.h>
18 #include <sys/prctl.h>
21 #ifndef PR_CAP_AMBIENT
22 #define PR_CAP_AMBIENT 47
23 # define PR_CAP_AMBIENT_IS_SET 1
24 # define PR_CAP_AMBIENT_RAISE 2
25 # define PR_CAP_AMBIENT_LOWER 3
26 # define PR_CAP_AMBIENT_CLEAR_ALL 4
31 static void vmaybe_write_file(bool enoent_ok, char *filename, char *fmt, va_list ap)
38 buf_len = vsnprintf(buf, sizeof(buf), fmt, ap);
40 err(1, "vsnprintf failed");
42 if (buf_len >= sizeof(buf)) {
43 errx(1, "vsnprintf output truncated");
46 fd = open(filename, O_WRONLY);
48 if ((errno == ENOENT) && enoent_ok)
50 err(1, "open of %s failed", filename);
52 written = write(fd, buf, buf_len);
53 if (written != buf_len) {
55 errx(1, "short write to %s", filename);
57 err(1, "write to %s failed", filename);
61 err(1, "close of %s failed", filename);
65 static void maybe_write_file(char *filename, char *fmt, ...)
70 vmaybe_write_file(true, filename, fmt, ap);
74 static void write_file(char *filename, char *fmt, ...)
79 vmaybe_write_file(false, filename, fmt, ap);
83 static bool create_and_enter_ns(uid_t inner_uid)
88 bool have_outer_privilege;
94 * TODO: If we're already root, we could skip creating the userns.
97 if (unshare(CLONE_NEWNS) == 0) {
98 printf("[NOTE]\tUsing global UIDs for tests\n");
99 if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) != 0)
100 err(1, "PR_SET_KEEPCAPS");
101 if (setresuid(inner_uid, inner_uid, -1) != 0)
104 // Re-enable effective caps
105 capng_get_caps_process();
106 for (i = 0; i < CAP_LAST_CAP; i++)
107 if (capng_have_capability(CAPNG_PERMITTED, i))
108 capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, i);
109 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
110 err(1, "capng_apply");
112 have_outer_privilege = true;
113 } else if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == 0) {
114 printf("[NOTE]\tUsing a user namespace for tests\n");
115 maybe_write_file("/proc/self/setgroups", "deny");
116 write_file("/proc/self/uid_map", "%d %d 1", inner_uid, outer_uid);
117 write_file("/proc/self/gid_map", "0 %d 1", outer_gid);
119 have_outer_privilege = false;
121 errx(1, "must be root or be able to create a userns");
124 if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL) != 0)
125 err(1, "remount everything private");
127 return have_outer_privilege;
130 static void chdir_to_tmpfs(void)
133 if (getcwd(cwd, sizeof(cwd)) != cwd)
136 if (mount("private_tmp", ".", "tmpfs", 0, "mode=0777") != 0)
137 err(1, "mount private tmpfs");
140 err(1, "chdir to private tmpfs");
143 static void copy_fromat_to(int fromfd, const char *fromname, const char *toname)
145 int from = openat(fromfd, fromname, O_RDONLY);
147 err(1, "open copy source");
149 int to = open(toname, O_CREAT | O_WRONLY | O_EXCL, 0700);
153 ssize_t sz = read(from, buf, sizeof(buf));
159 if (write(to, buf, sz) != sz)
160 err(1, "write"); /* no short writes on tmpfs */
167 static bool fork_wait(void)
169 pid_t child = fork();
173 } else if (child > 0) {
175 if (waitpid(child, &status, 0) != child ||
176 !WIFEXITED(status)) {
177 printf("[FAIL]\tChild died\n");
179 } else if (WEXITSTATUS(status) != 0) {
180 printf("[FAIL]\tChild failed\n");
183 printf("[OK]\tChild succeeded\n");
192 static void exec_other_validate_cap(const char *name,
193 bool eff, bool perm, bool inh, bool ambient)
195 execl(name, name, (eff ? "1" : "0"),
196 (perm ? "1" : "0"), (inh ? "1" : "0"), (ambient ? "1" : "0"),
201 static void exec_validate_cap(bool eff, bool perm, bool inh, bool ambient)
203 exec_other_validate_cap("./validate_cap", eff, perm, inh, ambient);
206 static int do_tests(int uid, const char *our_path)
208 bool have_outer_privilege = create_and_enter_ns(uid);
210 int ourpath_fd = open(our_path, O_RDONLY | O_DIRECTORY);
211 if (ourpath_fd == -1)
212 err(1, "open '%s'", our_path);
216 copy_fromat_to(ourpath_fd, "validate_cap", "validate_cap");
218 if (have_outer_privilege) {
219 uid_t gid = getegid();
221 copy_fromat_to(ourpath_fd, "validate_cap",
222 "validate_cap_suidroot");
223 if (chown("validate_cap_suidroot", 0, -1) != 0)
225 if (chmod("validate_cap_suidroot", S_ISUID | 0700) != 0)
228 copy_fromat_to(ourpath_fd, "validate_cap",
229 "validate_cap_suidnonroot");
230 if (chown("validate_cap_suidnonroot", uid + 1, -1) != 0)
232 if (chmod("validate_cap_suidnonroot", S_ISUID | 0700) != 0)
235 copy_fromat_to(ourpath_fd, "validate_cap",
236 "validate_cap_sgidroot");
237 if (chown("validate_cap_sgidroot", -1, 0) != 0)
239 if (chmod("validate_cap_sgidroot", S_ISGID | 0710) != 0)
242 copy_fromat_to(ourpath_fd, "validate_cap",
243 "validate_cap_sgidnonroot");
244 if (chown("validate_cap_sgidnonroot", -1, gid + 1) != 0)
246 if (chmod("validate_cap_sgidnonroot", S_ISGID | 0710) != 0)
250 capng_get_caps_process();
252 /* Make sure that i starts out clear */
253 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
254 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
255 err(1, "capng_apply");
258 printf("[RUN]\tRoot => ep\n");
260 exec_validate_cap(true, true, false, false);
262 printf("[RUN]\tNon-root => no caps\n");
264 exec_validate_cap(false, false, false, false);
267 printf("[OK]\tCheck cap_ambient manipulation rules\n");
269 /* We should not be able to add ambient caps yet. */
270 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != -1 || errno != EPERM) {
272 printf("[FAIL]\tPR_CAP_AMBIENT_RAISE isn't supported\n");
274 printf("[FAIL]\tPR_CAP_AMBIENT_RAISE should have failed eith EPERM on a non-inheritable cap\n");
277 printf("[OK]\tPR_CAP_AMBIENT_RAISE failed on non-inheritable cap\n");
279 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_RAW);
280 capng_update(CAPNG_DROP, CAPNG_PERMITTED, CAP_NET_RAW);
281 capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_NET_RAW);
282 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
283 err(1, "capng_apply");
284 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_RAW, 0, 0, 0) != -1 || errno != EPERM) {
285 printf("[FAIL]\tPR_CAP_AMBIENT_RAISE should have failed on a non-permitted cap\n");
288 printf("[OK]\tPR_CAP_AMBIENT_RAISE failed on non-permitted cap\n");
290 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
291 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
292 err(1, "capng_apply");
293 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
294 printf("[FAIL]\tPR_CAP_AMBIENT_RAISE should have succeeded\n");
297 printf("[OK]\tPR_CAP_AMBIENT_RAISE worked\n");
299 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 1) {
300 printf("[FAIL]\tPR_CAP_AMBIENT_IS_SET is broken\n");
304 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0, 0, 0, 0) != 0)
305 err(1, "PR_CAP_AMBIENT_CLEAR_ALL");
307 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
308 printf("[FAIL]\tPR_CAP_AMBIENT_CLEAR_ALL didn't work\n");
312 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)
313 err(1, "PR_CAP_AMBIENT_RAISE");
315 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
316 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
317 err(1, "capng_apply");
319 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
320 printf("[FAIL]\tDropping I should have dropped A\n");
324 printf("[OK]\tBasic manipulation appears to work\n");
326 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
327 if (capng_apply(CAPNG_SELECT_CAPS) != 0)
328 err(1, "capng_apply");
330 printf("[RUN]\tRoot +i => eip\n");
332 exec_validate_cap(true, true, true, false);
334 printf("[RUN]\tNon-root +i => i\n");
336 exec_validate_cap(false, false, true, false);
339 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)
340 err(1, "PR_CAP_AMBIENT_RAISE");
342 printf("[RUN]\tUID %d +ia => eipa\n", uid);
344 exec_validate_cap(true, true, true, true);
346 /* The remaining tests need real privilege */
348 if (!have_outer_privilege) {
349 printf("[SKIP]\tSUID/SGID tests (needs privilege)\n");
354 printf("[RUN]\tRoot +ia, suidroot => eipa\n");
356 exec_other_validate_cap("./validate_cap_suidroot",
357 true, true, true, true);
359 printf("[RUN]\tRoot +ia, suidnonroot => ip\n");
361 exec_other_validate_cap("./validate_cap_suidnonroot",
362 false, true, true, false);
364 printf("[RUN]\tRoot +ia, sgidroot => eipa\n");
366 exec_other_validate_cap("./validate_cap_sgidroot",
367 true, true, true, true);
370 printf("[RUN]\tRoot, gid != 0, +ia, sgidroot => eip\n");
371 if (setresgid(1, 1, 1) != 0)
373 exec_other_validate_cap("./validate_cap_sgidroot",
374 true, true, true, false);
377 printf("[RUN]\tRoot +ia, sgidnonroot => eip\n");
379 exec_other_validate_cap("./validate_cap_sgidnonroot",
380 true, true, true, false);
382 printf("[RUN]\tNon-root +ia, sgidnonroot => i\n");
383 exec_other_validate_cap("./validate_cap_sgidnonroot",
384 false, false, true, false);
387 printf("[RUN]\tNon-root +ia, sgidroot => i\n");
388 if (setresgid(1, 1, 1) != 0)
390 exec_other_validate_cap("./validate_cap_sgidroot",
391 false, false, true, false);
396 return nerrs ? 1 : 0;
399 int main(int argc, char **argv)
401 char *tmp1, *tmp2, *our_path;
404 tmp1 = strdup(argv[0]);
407 tmp2 = dirname(tmp1);
408 our_path = strdup(tmp2);
414 printf("[RUN]\t+++ Tests with uid == 0 +++\n");
415 return do_tests(0, our_path);
419 printf("[RUN]\t+++ Tests with uid != 0 +++\n");
420 return do_tests(1, our_path);
423 return nerrs ? 1 : 0;