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 30 static int nerrs; 31 static pid_t mpid; /* main() pid is used to avoid duplicate test counts */ 32 33 static 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 70 static 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 79 static 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 88 static 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 } 137 138 static 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 } 152 153 static 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 } 177 178 static 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 } 204 205 static 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 } 213 214 static 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 } 218 219 static 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 } 422 423 done: 424 ksft_print_cnts(); 425 return nerrs ? 1 : 0; 426 } 427 428 int 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 } 460