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; 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("[NOTE]\tUsing global UIDs for tests\n"); 97 if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) != 0) 98 ksft_exit_fail_msg("PR_SET_KEEPCAPS - %s\n", 99 strerror(errno)); 100 if (setresuid(inner_uid, inner_uid, -1) != 0) 101 ksft_exit_fail_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 "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("[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); 118 119 have_outer_privilege = false; 120 } else { 121 ksft_exit_skip("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("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("getcwd - %s\n", strerror(errno)); 136 137 if (mount("private_tmp", ".", "tmpfs", 0, "mode=0777") != 0) 138 ksft_exit_fail_msg("mount private tmpfs - %s\n", 139 strerror(errno)); 140 141 if (chdir(cwd) != 0) 142 ksft_exit_fail_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("Child died\n"); 182 nerrs++; 183 } else if (WEXITSTATUS(status) != 0) { 184 ksft_print_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("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("./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(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 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("[RUN]\tRoot => ep\n"); 266 if (fork_wait()) 267 exec_validate_cap(true, true, false, false); 268 } else { 269 ksft_print_msg("[RUN]\tNon-root => no caps\n"); 270 if (fork_wait()) 271 exec_validate_cap(false, false, false, false); 272 } 273 274 ksft_print_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 "PR_CAP_AMBIENT_RAISE isn't supported\n"); 281 else 282 ksft_test_result_fail( 283 "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 "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 "PR_CAP_AMBIENT_RAISE should have failed on a non-permitted cap\n"); 297 return 1; 298 } 299 ksft_test_result_pass( 300 "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 "PR_CAP_AMBIENT_RAISE should have succeeded\n"); 308 return 1; 309 } 310 ksft_test_result_pass("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("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 "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("Dropping I should have dropped A\n"); 337 return 1; 338 } 339 340 ksft_test_result_pass("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("[RUN]\tRoot +i => eip\n"); 347 if (fork_wait()) 348 exec_validate_cap(true, true, true, false); 349 } else { 350 ksft_print_msg("[RUN]\tNon-root +i => i\n"); 351 if (fork_wait()) 352 exec_validate_cap(false, false, true, 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("[RUN]\tUID %d +ia => eipa\n", uid); 360 if (fork_wait()) 361 exec_validate_cap(true, true, true, true); 362 363 /* The remaining tests need real privilege */ 364 365 if (!have_outer_privilege) { 366 ksft_test_result_skip("SUID/SGID tests (needs privilege)\n"); 367 goto done; 368 } 369 370 if (uid == 0) { 371 ksft_print_msg("[RUN]\tRoot +ia, suidroot => eipa\n"); 372 if (fork_wait()) 373 exec_other_validate_cap("./validate_cap_suidroot", 374 true, true, true, true); 375 376 ksft_print_msg("[RUN]\tRoot +ia, suidnonroot => ip\n"); 377 if (fork_wait()) 378 exec_other_validate_cap("./validate_cap_suidnonroot", 379 false, true, true, false); 380 381 ksft_print_msg("[RUN]\tRoot +ia, sgidroot => eipa\n"); 382 if (fork_wait()) 383 exec_other_validate_cap("./validate_cap_sgidroot", 384 true, true, true, true); 385 386 if (fork_wait()) { 387 ksft_print_msg( 388 "[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("./validate_cap_sgidroot", 393 true, true, true, false); 394 } 395 396 ksft_print_msg("[RUN]\tRoot +ia, sgidnonroot => eip\n"); 397 if (fork_wait()) 398 exec_other_validate_cap("./validate_cap_sgidnonroot", 399 true, true, true, false); 400 } else { 401 ksft_print_msg("[RUN]\tNon-root +ia, sgidnonroot => i\n"); 402 if (fork_wait()) 403 exec_other_validate_cap("./validate_cap_sgidnonroot", 404 false, false, true, false); 405 406 if (fork_wait()) { 407 ksft_print_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("./validate_cap_sgidroot", 412 false, false, true, 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(12); 440 ksft_print_msg("[RUN]\t+++ Tests with uid == 0 +++\n"); 441 return do_tests(0, our_path); 442 } 443 444 ksft_print_msg("==================================================\n"); 445 446 if (fork_wait()) { 447 ksft_print_header(); 448 ksft_set_plan(9); 449 ksft_print_msg("[RUN]\t+++ Tests with uid != 0 +++\n"); 450 return do_tests(1, our_path); 451 } 452 453 return nerrs ? 1 : 0; 454 } 455