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("vsnprintf failed - %s\n", strerror(errno)); 36 37 if (buf_len >= sizeof(buf)) 38 ksft_exit_fail_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("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("short write to %s\n", filename); 52 } else { 53 ksft_exit_fail_msg("write to %s failed - %s\n", 54 filename, strerror(errno)); 55 } 56 } 57 if (close(fd) != 0) { 58 ksft_exit_fail_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, ret; 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("[NOTE]\tUsing global UIDs for tests\n"); 93 if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) != 0) 94 ksft_exit_fail_msg("PR_SET_KEEPCAPS - %s\n", 95 strerror(errno)); 96 if (setresuid(inner_uid, inner_uid, -1) != 0) 97 ksft_exit_fail_msg("setresuid - %s\n", strerror(errno)); 98 99 // Re-enable effective caps 100 ret = capng_get_caps_process(); 101 if (ret == -1) 102 ksft_exit_fail_msg("capng_get_caps_process failed\n"); 103 104 for (i = 0; i < CAP_LAST_CAP; i++) 105 if (capng_have_capability(CAPNG_PERMITTED, i)) 106 capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, i); 107 if (capng_apply(CAPNG_SELECT_CAPS) != 0) 108 ksft_exit_fail_msg( 109 "capng_apply - %s\n", strerror(errno)); 110 111 have_outer_privilege = true; 112 } else if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == 0) { 113 ksft_print_msg("[NOTE]\tUsing a user namespace for tests\n"); 114 maybe_write_file("/proc/self/setgroups", "deny"); 115 write_file("/proc/self/uid_map", "%d %d 1", inner_uid, outer_uid); 116 write_file("/proc/self/gid_map", "0 %d 1", outer_gid); 117 118 have_outer_privilege = false; 119 } else { 120 ksft_exit_skip("must be root or be able to create a userns\n"); 121 } 122 123 if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL) != 0) 124 ksft_exit_fail_msg("remount everything private - %s\n", 125 strerror(errno)); 126 127 return have_outer_privilege; 128 } 129 130 static void chdir_to_tmpfs(void) 131 { 132 char cwd[PATH_MAX]; 133 if (getcwd(cwd, sizeof(cwd)) != cwd) 134 ksft_exit_fail_msg("getcwd - %s\n", strerror(errno)); 135 136 if (mount("private_tmp", ".", "tmpfs", 0, "mode=0777") != 0) 137 ksft_exit_fail_msg("mount private tmpfs - %s\n", 138 strerror(errno)); 139 140 if (chdir(cwd) != 0) 141 ksft_exit_fail_msg("chdir to private tmpfs - %s\n", 142 strerror(errno)); 143 } 144 145 static void copy_fromat_to(int fromfd, const char *fromname, const char *toname) 146 { 147 int from = openat(fromfd, fromname, O_RDONLY); 148 if (from == -1) 149 ksft_exit_fail_msg("open copy source - %s\n", strerror(errno)); 150 151 int to = open(toname, O_CREAT | O_WRONLY | O_EXCL, 0700); 152 153 while (true) { 154 char buf[4096]; 155 ssize_t sz = read(from, buf, sizeof(buf)); 156 if (sz == 0) 157 break; 158 if (sz < 0) 159 ksft_exit_fail_msg("read - %s\n", strerror(errno)); 160 161 if (write(to, buf, sz) != sz) 162 /* no short writes on tmpfs */ 163 ksft_exit_fail_msg("write - %s\n", strerror(errno)); 164 } 165 166 close(from); 167 close(to); 168 } 169 170 static bool fork_wait(void) 171 { 172 pid_t child = fork(); 173 if (child == 0) { 174 nerrs = 0; 175 return true; 176 } else if (child > 0) { 177 int status; 178 if (waitpid(child, &status, 0) != child || 179 !WIFEXITED(status)) { 180 ksft_print_msg("Child died\n"); 181 nerrs++; 182 } else if (WEXITSTATUS(status) != 0) { 183 ksft_print_msg("Child failed\n"); 184 nerrs++; 185 } else { 186 /* don't print this message for mpid */ 187 if (getpid() != mpid) 188 ksft_test_result_pass("Passed\n"); 189 } 190 return false; 191 } else { 192 ksft_exit_fail_msg("fork - %s\n", strerror(errno)); 193 return false; 194 } 195 } 196 197 static void exec_other_validate_cap(const char *name, 198 bool eff, bool perm, bool inh, bool ambient) 199 { 200 execl(name, name, (eff ? "1" : "0"), 201 (perm ? "1" : "0"), (inh ? "1" : "0"), (ambient ? "1" : "0"), 202 NULL); 203 ksft_exit_fail_msg("execl - %s\n", strerror(errno)); 204 } 205 206 static void exec_validate_cap(bool eff, bool perm, bool inh, bool ambient) 207 { 208 exec_other_validate_cap("./validate_cap", eff, perm, inh, ambient); 209 } 210 211 static int do_tests(int uid, const char *our_path) 212 { 213 int ret; 214 bool have_outer_privilege = create_and_enter_ns(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(ourpath_fd, "validate_cap", "validate_cap"); 224 225 if (have_outer_privilege) { 226 uid_t gid = getegid(); 227 228 copy_fromat_to(ourpath_fd, "validate_cap", 229 "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(ourpath_fd, "validate_cap", 236 "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(ourpath_fd, "validate_cap", 243 "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(ourpath_fd, "validate_cap", 250 "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 ret = capng_get_caps_process(); 258 if (ret == -1) 259 ksft_exit_fail_msg("capng_get_caps_process failed\n"); 260 261 /* Make sure that i starts out clear */ 262 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE); 263 if (capng_apply(CAPNG_SELECT_CAPS) != 0) 264 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno)); 265 266 if (uid == 0) { 267 ksft_print_msg("[RUN]\tRoot => ep\n"); 268 if (fork_wait()) 269 exec_validate_cap(true, true, false, false); 270 } else { 271 ksft_print_msg("[RUN]\tNon-root => no caps\n"); 272 if (fork_wait()) 273 exec_validate_cap(false, false, false, false); 274 } 275 276 ksft_print_msg("Check cap_ambient manipulation rules\n"); 277 278 /* We should not be able to add ambient caps yet. */ 279 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != -1 || errno != EPERM) { 280 if (errno == EINVAL) 281 ksft_test_result_fail( 282 "PR_CAP_AMBIENT_RAISE isn't supported\n"); 283 else 284 ksft_test_result_fail( 285 "PR_CAP_AMBIENT_RAISE should have failed eith EPERM on a non-inheritable cap\n"); 286 return 1; 287 } 288 ksft_test_result_pass( 289 "PR_CAP_AMBIENT_RAISE failed on non-inheritable cap\n"); 290 291 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_RAW); 292 capng_update(CAPNG_DROP, CAPNG_PERMITTED, CAP_NET_RAW); 293 capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_NET_RAW); 294 if (capng_apply(CAPNG_SELECT_CAPS) != 0) 295 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno)); 296 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_RAW, 0, 0, 0) != -1 || errno != EPERM) { 297 ksft_test_result_fail( 298 "PR_CAP_AMBIENT_RAISE should have failed on a non-permitted cap\n"); 299 return 1; 300 } 301 ksft_test_result_pass( 302 "PR_CAP_AMBIENT_RAISE failed on non-permitted cap\n"); 303 304 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE); 305 if (capng_apply(CAPNG_SELECT_CAPS) != 0) 306 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno)); 307 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) { 308 ksft_test_result_fail( 309 "PR_CAP_AMBIENT_RAISE should have succeeded\n"); 310 return 1; 311 } 312 ksft_test_result_pass("PR_CAP_AMBIENT_RAISE worked\n"); 313 314 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 1) { 315 ksft_test_result_fail("PR_CAP_AMBIENT_IS_SET is broken\n"); 316 return 1; 317 } 318 319 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0, 0, 0, 0) != 0) 320 ksft_exit_fail_msg("PR_CAP_AMBIENT_CLEAR_ALL - %s\n", 321 strerror(errno)); 322 323 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) { 324 ksft_test_result_fail( 325 "PR_CAP_AMBIENT_CLEAR_ALL didn't work\n"); 326 return 1; 327 } 328 329 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) 330 ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n", 331 strerror(errno)); 332 333 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE); 334 if (capng_apply(CAPNG_SELECT_CAPS) != 0) 335 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno)); 336 337 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) { 338 ksft_test_result_fail("Dropping I should have dropped A\n"); 339 return 1; 340 } 341 342 ksft_test_result_pass("Basic manipulation appears to work\n"); 343 344 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE); 345 if (capng_apply(CAPNG_SELECT_CAPS) != 0) 346 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno)); 347 if (uid == 0) { 348 ksft_print_msg("[RUN]\tRoot +i => eip\n"); 349 if (fork_wait()) 350 exec_validate_cap(true, true, true, false); 351 } else { 352 ksft_print_msg("[RUN]\tNon-root +i => i\n"); 353 if (fork_wait()) 354 exec_validate_cap(false, false, true, false); 355 } 356 357 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) 358 ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n", 359 strerror(errno)); 360 361 ksft_print_msg("[RUN]\tUID %d +ia => eipa\n", uid); 362 if (fork_wait()) 363 exec_validate_cap(true, true, true, true); 364 365 /* The remaining tests need real privilege */ 366 367 if (!have_outer_privilege) { 368 ksft_test_result_skip("SUID/SGID tests (needs privilege)\n"); 369 goto done; 370 } 371 372 if (uid == 0) { 373 ksft_print_msg("[RUN]\tRoot +ia, suidroot => eipa\n"); 374 if (fork_wait()) 375 exec_other_validate_cap("./validate_cap_suidroot", 376 true, true, true, true); 377 378 ksft_print_msg("[RUN]\tRoot +ia, suidnonroot => ip\n"); 379 if (fork_wait()) 380 exec_other_validate_cap("./validate_cap_suidnonroot", 381 false, true, true, false); 382 383 ksft_print_msg("[RUN]\tRoot +ia, sgidroot => eipa\n"); 384 if (fork_wait()) 385 exec_other_validate_cap("./validate_cap_sgidroot", 386 true, true, true, true); 387 388 if (fork_wait()) { 389 ksft_print_msg( 390 "[RUN]\tRoot, gid != 0, +ia, sgidroot => eip\n"); 391 if (setresgid(1, 1, 1) != 0) 392 ksft_exit_fail_msg("setresgid - %s\n", 393 strerror(errno)); 394 exec_other_validate_cap("./validate_cap_sgidroot", 395 true, true, true, false); 396 } 397 398 ksft_print_msg("[RUN]\tRoot +ia, sgidnonroot => eip\n"); 399 if (fork_wait()) 400 exec_other_validate_cap("./validate_cap_sgidnonroot", 401 true, true, true, false); 402 } else { 403 ksft_print_msg("[RUN]\tNon-root +ia, sgidnonroot => i\n"); 404 if (fork_wait()) 405 exec_other_validate_cap("./validate_cap_sgidnonroot", 406 false, false, true, false); 407 408 if (fork_wait()) { 409 ksft_print_msg("[RUN]\tNon-root +ia, sgidroot => i\n"); 410 if (setresgid(1, 1, 1) != 0) 411 ksft_exit_fail_msg("setresgid - %s\n", 412 strerror(errno)); 413 exec_other_validate_cap("./validate_cap_sgidroot", 414 false, false, true, false); 415 } 416 } 417 418 done: 419 ksft_print_cnts(); 420 return nerrs ? 1 : 0; 421 } 422 423 int main(int argc, char **argv) 424 { 425 char *tmp1, *tmp2, *our_path; 426 427 /* Find our path */ 428 tmp1 = strdup(argv[0]); 429 if (!tmp1) 430 ksft_exit_fail_msg("strdup - %s\n", strerror(errno)); 431 tmp2 = dirname(tmp1); 432 our_path = strdup(tmp2); 433 if (!our_path) 434 ksft_exit_fail_msg("strdup - %s\n", strerror(errno)); 435 free(tmp1); 436 437 mpid = getpid(); 438 439 if (fork_wait()) { 440 ksft_print_header(); 441 ksft_set_plan(12); 442 ksft_print_msg("[RUN]\t+++ Tests with uid == 0 +++\n"); 443 return do_tests(0, our_path); 444 } 445 446 ksft_print_msg("==================================================\n"); 447 448 if (fork_wait()) { 449 ksft_print_header(); 450 ksft_set_plan(9); 451 ksft_print_msg("[RUN]\t+++ Tests with uid != 0 +++\n"); 452 return do_tests(1, our_path); 453 } 454 455 return nerrs ? 1 : 0; 456 } 457