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 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 capng_get_caps_process(); 101 for (i = 0; i < CAP_LAST_CAP; i++) 102 if (capng_have_capability(CAPNG_PERMITTED, i)) 103 capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, i); 104 if (capng_apply(CAPNG_SELECT_CAPS) != 0) 105 ksft_exit_fail_msg( 106 "capng_apply - %s\n", strerror(errno)); 107 108 have_outer_privilege = true; 109 } else if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == 0) { 110 ksft_print_msg("[NOTE]\tUsing a user namespace for tests\n"); 111 maybe_write_file("/proc/self/setgroups", "deny"); 112 write_file("/proc/self/uid_map", "%d %d 1", inner_uid, outer_uid); 113 write_file("/proc/self/gid_map", "0 %d 1", outer_gid); 114 115 have_outer_privilege = false; 116 } else { 117 ksft_exit_skip("must be root or be able to create a userns\n"); 118 } 119 120 if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL) != 0) 121 ksft_exit_fail_msg("remount everything private - %s\n", 122 strerror(errno)); 123 124 return have_outer_privilege; 125 } 126 127 static void chdir_to_tmpfs(void) 128 { 129 char cwd[PATH_MAX]; 130 if (getcwd(cwd, sizeof(cwd)) != cwd) 131 ksft_exit_fail_msg("getcwd - %s\n", strerror(errno)); 132 133 if (mount("private_tmp", ".", "tmpfs", 0, "mode=0777") != 0) 134 ksft_exit_fail_msg("mount private tmpfs - %s\n", 135 strerror(errno)); 136 137 if (chdir(cwd) != 0) 138 ksft_exit_fail_msg("chdir to private tmpfs - %s\n", 139 strerror(errno)); 140 } 141 142 static void copy_fromat_to(int fromfd, const char *fromname, const char *toname) 143 { 144 int from = openat(fromfd, fromname, O_RDONLY); 145 if (from == -1) 146 ksft_exit_fail_msg("open copy source - %s\n", strerror(errno)); 147 148 int to = open(toname, O_CREAT | O_WRONLY | O_EXCL, 0700); 149 150 while (true) { 151 char buf[4096]; 152 ssize_t sz = read(from, buf, sizeof(buf)); 153 if (sz == 0) 154 break; 155 if (sz < 0) 156 ksft_exit_fail_msg("read - %s\n", strerror(errno)); 157 158 if (write(to, buf, sz) != sz) 159 /* no short writes on tmpfs */ 160 ksft_exit_fail_msg("write - %s\n", strerror(errno)); 161 } 162 163 close(from); 164 close(to); 165 } 166 167 static bool fork_wait(void) 168 { 169 pid_t child = fork(); 170 if (child == 0) { 171 nerrs = 0; 172 return true; 173 } else if (child > 0) { 174 int status; 175 if (waitpid(child, &status, 0) != child || 176 !WIFEXITED(status)) { 177 ksft_print_msg("Child died\n"); 178 nerrs++; 179 } else if (WEXITSTATUS(status) != 0) { 180 ksft_print_msg("Child failed\n"); 181 nerrs++; 182 } else { 183 /* don't print this message for mpid */ 184 if (getpid() != mpid) 185 ksft_test_result_pass("Passed\n"); 186 } 187 return false; 188 } else { 189 ksft_exit_fail_msg("fork - %s\n", strerror(errno)); 190 return false; 191 } 192 } 193 194 static void exec_other_validate_cap(const char *name, 195 bool eff, bool perm, bool inh, bool ambient) 196 { 197 execl(name, name, (eff ? "1" : "0"), 198 (perm ? "1" : "0"), (inh ? "1" : "0"), (ambient ? "1" : "0"), 199 NULL); 200 ksft_exit_fail_msg("execl - %s\n", strerror(errno)); 201 } 202 203 static void exec_validate_cap(bool eff, bool perm, bool inh, bool ambient) 204 { 205 exec_other_validate_cap("./validate_cap", eff, perm, inh, ambient); 206 } 207 208 static int do_tests(int uid, const char *our_path) 209 { 210 bool have_outer_privilege = create_and_enter_ns(uid); 211 212 int ourpath_fd = open(our_path, O_RDONLY | O_DIRECTORY); 213 if (ourpath_fd == -1) 214 ksft_exit_fail_msg("open '%s' - %s\n", 215 our_path, strerror(errno)); 216 217 chdir_to_tmpfs(); 218 219 copy_fromat_to(ourpath_fd, "validate_cap", "validate_cap"); 220 221 if (have_outer_privilege) { 222 uid_t gid = getegid(); 223 224 copy_fromat_to(ourpath_fd, "validate_cap", 225 "validate_cap_suidroot"); 226 if (chown("validate_cap_suidroot", 0, -1) != 0) 227 ksft_exit_fail_msg("chown - %s\n", strerror(errno)); 228 if (chmod("validate_cap_suidroot", S_ISUID | 0700) != 0) 229 ksft_exit_fail_msg("chmod - %s\n", strerror(errno)); 230 231 copy_fromat_to(ourpath_fd, "validate_cap", 232 "validate_cap_suidnonroot"); 233 if (chown("validate_cap_suidnonroot", uid + 1, -1) != 0) 234 ksft_exit_fail_msg("chown - %s\n", strerror(errno)); 235 if (chmod("validate_cap_suidnonroot", S_ISUID | 0700) != 0) 236 ksft_exit_fail_msg("chmod - %s\n", strerror(errno)); 237 238 copy_fromat_to(ourpath_fd, "validate_cap", 239 "validate_cap_sgidroot"); 240 if (chown("validate_cap_sgidroot", -1, 0) != 0) 241 ksft_exit_fail_msg("chown - %s\n", strerror(errno)); 242 if (chmod("validate_cap_sgidroot", S_ISGID | 0710) != 0) 243 ksft_exit_fail_msg("chmod - %s\n", strerror(errno)); 244 245 copy_fromat_to(ourpath_fd, "validate_cap", 246 "validate_cap_sgidnonroot"); 247 if (chown("validate_cap_sgidnonroot", -1, gid + 1) != 0) 248 ksft_exit_fail_msg("chown - %s\n", strerror(errno)); 249 if (chmod("validate_cap_sgidnonroot", S_ISGID | 0710) != 0) 250 ksft_exit_fail_msg("chmod - %s\n", strerror(errno)); 251 } 252 253 capng_get_caps_process(); 254 255 /* Make sure that i starts out clear */ 256 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE); 257 if (capng_apply(CAPNG_SELECT_CAPS) != 0) 258 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno)); 259 260 if (uid == 0) { 261 ksft_print_msg("[RUN]\tRoot => ep\n"); 262 if (fork_wait()) 263 exec_validate_cap(true, true, false, false); 264 } else { 265 ksft_print_msg("[RUN]\tNon-root => no caps\n"); 266 if (fork_wait()) 267 exec_validate_cap(false, false, false, false); 268 } 269 270 ksft_print_msg("Check cap_ambient manipulation rules\n"); 271 272 /* We should not be able to add ambient caps yet. */ 273 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != -1 || errno != EPERM) { 274 if (errno == EINVAL) 275 ksft_test_result_fail( 276 "PR_CAP_AMBIENT_RAISE isn't supported\n"); 277 else 278 ksft_test_result_fail( 279 "PR_CAP_AMBIENT_RAISE should have failed eith EPERM on a non-inheritable cap\n"); 280 return 1; 281 } 282 ksft_test_result_pass( 283 "PR_CAP_AMBIENT_RAISE failed on non-inheritable cap\n"); 284 285 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_RAW); 286 capng_update(CAPNG_DROP, CAPNG_PERMITTED, CAP_NET_RAW); 287 capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_NET_RAW); 288 if (capng_apply(CAPNG_SELECT_CAPS) != 0) 289 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno)); 290 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_RAW, 0, 0, 0) != -1 || errno != EPERM) { 291 ksft_test_result_fail( 292 "PR_CAP_AMBIENT_RAISE should have failed on a non-permitted cap\n"); 293 return 1; 294 } 295 ksft_test_result_pass( 296 "PR_CAP_AMBIENT_RAISE failed on non-permitted cap\n"); 297 298 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE); 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_BIND_SERVICE, 0, 0, 0) != 0) { 302 ksft_test_result_fail( 303 "PR_CAP_AMBIENT_RAISE should have succeeded\n"); 304 return 1; 305 } 306 ksft_test_result_pass("PR_CAP_AMBIENT_RAISE worked\n"); 307 308 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 1) { 309 ksft_test_result_fail("PR_CAP_AMBIENT_IS_SET is broken\n"); 310 return 1; 311 } 312 313 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0, 0, 0, 0) != 0) 314 ksft_exit_fail_msg("PR_CAP_AMBIENT_CLEAR_ALL - %s\n", 315 strerror(errno)); 316 317 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) { 318 ksft_test_result_fail( 319 "PR_CAP_AMBIENT_CLEAR_ALL didn't work\n"); 320 return 1; 321 } 322 323 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) 324 ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n", 325 strerror(errno)); 326 327 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE); 328 if (capng_apply(CAPNG_SELECT_CAPS) != 0) 329 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno)); 330 331 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) { 332 ksft_test_result_fail("Dropping I should have dropped A\n"); 333 return 1; 334 } 335 336 ksft_test_result_pass("Basic manipulation appears to work\n"); 337 338 capng_update(CAPNG_ADD, 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 if (uid == 0) { 342 ksft_print_msg("[RUN]\tRoot +i => eip\n"); 343 if (fork_wait()) 344 exec_validate_cap(true, true, true, false); 345 } else { 346 ksft_print_msg("[RUN]\tNon-root +i => i\n"); 347 if (fork_wait()) 348 exec_validate_cap(false, false, true, false); 349 } 350 351 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) 352 ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n", 353 strerror(errno)); 354 355 ksft_print_msg("[RUN]\tUID %d +ia => eipa\n", uid); 356 if (fork_wait()) 357 exec_validate_cap(true, true, true, true); 358 359 /* The remaining tests need real privilege */ 360 361 if (!have_outer_privilege) { 362 ksft_test_result_skip("SUID/SGID tests (needs privilege)\n"); 363 goto done; 364 } 365 366 if (uid == 0) { 367 ksft_print_msg("[RUN]\tRoot +ia, suidroot => eipa\n"); 368 if (fork_wait()) 369 exec_other_validate_cap("./validate_cap_suidroot", 370 true, true, true, true); 371 372 ksft_print_msg("[RUN]\tRoot +ia, suidnonroot => ip\n"); 373 if (fork_wait()) 374 exec_other_validate_cap("./validate_cap_suidnonroot", 375 false, true, true, false); 376 377 ksft_print_msg("[RUN]\tRoot +ia, sgidroot => eipa\n"); 378 if (fork_wait()) 379 exec_other_validate_cap("./validate_cap_sgidroot", 380 true, true, true, true); 381 382 if (fork_wait()) { 383 ksft_print_msg( 384 "[RUN]\tRoot, gid != 0, +ia, sgidroot => eip\n"); 385 if (setresgid(1, 1, 1) != 0) 386 ksft_exit_fail_msg("setresgid - %s\n", 387 strerror(errno)); 388 exec_other_validate_cap("./validate_cap_sgidroot", 389 true, true, true, false); 390 } 391 392 ksft_print_msg("[RUN]\tRoot +ia, sgidnonroot => eip\n"); 393 if (fork_wait()) 394 exec_other_validate_cap("./validate_cap_sgidnonroot", 395 true, true, true, false); 396 } else { 397 ksft_print_msg("[RUN]\tNon-root +ia, sgidnonroot => i\n"); 398 if (fork_wait()) 399 exec_other_validate_cap("./validate_cap_sgidnonroot", 400 false, false, true, false); 401 402 if (fork_wait()) { 403 ksft_print_msg("[RUN]\tNon-root +ia, sgidroot => i\n"); 404 if (setresgid(1, 1, 1) != 0) 405 ksft_exit_fail_msg("setresgid - %s\n", 406 strerror(errno)); 407 exec_other_validate_cap("./validate_cap_sgidroot", 408 false, false, true, false); 409 } 410 } 411 412 done: 413 ksft_print_cnts(); 414 return nerrs ? 1 : 0; 415 } 416 417 int main(int argc, char **argv) 418 { 419 char *tmp1, *tmp2, *our_path; 420 421 /* Find our path */ 422 tmp1 = strdup(argv[0]); 423 if (!tmp1) 424 ksft_exit_fail_msg("strdup - %s\n", strerror(errno)); 425 tmp2 = dirname(tmp1); 426 our_path = strdup(tmp2); 427 if (!our_path) 428 ksft_exit_fail_msg("strdup - %s\n", strerror(errno)); 429 free(tmp1); 430 431 mpid = getpid(); 432 433 if (fork_wait()) { 434 ksft_print_header(); 435 ksft_set_plan(12); 436 ksft_print_msg("[RUN]\t+++ Tests with uid == 0 +++\n"); 437 return do_tests(0, our_path); 438 } 439 440 ksft_print_msg("==================================================\n"); 441 442 if (fork_wait()) { 443 ksft_print_header(); 444 ksft_set_plan(9); 445 ksft_print_msg("[RUN]\t+++ Tests with uid != 0 +++\n"); 446 return do_tests(1, our_path); 447 } 448 449 return nerrs ? 1 : 0; 450 } 451