1 // SPDX-License-Identifier: BSD-3-Clause 2 /* 3 * Simple Landlock sandbox manager able to execute a process restricted by 4 * user-defined file system and network access control policies. 5 * 6 * Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net> 7 * Copyright © 2020 ANSSI 8 */ 9 10 #define _GNU_SOURCE 11 #define __SANE_USERSPACE_TYPES__ 12 #include <arpa/inet.h> 13 #include <errno.h> 14 #include <fcntl.h> 15 #include <linux/landlock.h> 16 #include <linux/socket.h> 17 #include <stddef.h> 18 #include <stdio.h> 19 #include <stdlib.h> 20 #include <string.h> 21 #include <sys/prctl.h> 22 #include <sys/stat.h> 23 #include <sys/syscall.h> 24 #include <unistd.h> 25 #include <stdbool.h> 26 27 #if defined(__GLIBC__) 28 #include <linux/prctl.h> 29 #endif 30 31 #ifndef landlock_create_ruleset 32 static inline int 33 landlock_create_ruleset(const struct landlock_ruleset_attr *const attr, 34 const size_t size, const __u32 flags) 35 { 36 return syscall(__NR_landlock_create_ruleset, attr, size, flags); 37 } 38 #endif 39 40 #ifndef landlock_add_rule 41 static inline int landlock_add_rule(const int ruleset_fd, 42 const enum landlock_rule_type rule_type, 43 const void *const rule_attr, 44 const __u32 flags) 45 { 46 return syscall(__NR_landlock_add_rule, ruleset_fd, rule_type, rule_attr, 47 flags); 48 } 49 #endif 50 51 #ifndef landlock_restrict_self 52 static inline int landlock_restrict_self(const int ruleset_fd, 53 const __u32 flags) 54 { 55 return syscall(__NR_landlock_restrict_self, ruleset_fd, flags); 56 } 57 #endif 58 59 #define ENV_FS_RO_NAME "LL_FS_RO" 60 #define ENV_FS_RW_NAME "LL_FS_RW" 61 #define ENV_FS_QUIET_NAME "LL_FS_QUIET" 62 #define ENV_TCP_BIND_NAME "LL_TCP_BIND" 63 #define ENV_TCP_CONNECT_NAME "LL_TCP_CONNECT" 64 #define ENV_NET_QUIET_NAME "LL_NET_QUIET" 65 #define ENV_SCOPED_NAME "LL_SCOPED" 66 #define ENV_QUIET_ACCESS_NAME "LL_QUIET_ACCESS" 67 #define ENV_FORCE_LOG_NAME "LL_FORCE_LOG" 68 #define ENV_UDP_BIND_NAME "LL_UDP_BIND" 69 #define ENV_UDP_CONNECT_SEND_NAME "LL_UDP_CONNECT_SEND" 70 #define ENV_DELIMITER ":" 71 72 static int str2num(const char *numstr, __u64 *num_dst) 73 { 74 char *endptr = NULL; 75 int err = 0; 76 __u64 num; 77 78 errno = 0; 79 num = strtoull(numstr, &endptr, 10); 80 if (errno != 0) 81 err = errno; 82 /* Was the string empty, or not entirely parsed successfully? */ 83 else if ((*numstr == '\0') || (*endptr != '\0')) 84 err = EINVAL; 85 else 86 *num_dst = num; 87 88 return err; 89 } 90 91 static int parse_path(char *env_path, const char ***const path_list) 92 { 93 int i, num_paths = 0; 94 95 if (env_path) { 96 num_paths++; 97 for (i = 0; env_path[i]; i++) { 98 if (env_path[i] == ENV_DELIMITER[0]) 99 num_paths++; 100 } 101 } 102 *path_list = malloc(num_paths * sizeof(**path_list)); 103 if (!*path_list) 104 return -1; 105 106 for (i = 0; i < num_paths; i++) 107 (*path_list)[i] = strsep(&env_path, ENV_DELIMITER); 108 109 return num_paths; 110 } 111 112 /* clang-format off */ 113 114 #define ACCESS_FILE ( \ 115 LANDLOCK_ACCESS_FS_EXECUTE | \ 116 LANDLOCK_ACCESS_FS_WRITE_FILE | \ 117 LANDLOCK_ACCESS_FS_READ_FILE | \ 118 LANDLOCK_ACCESS_FS_TRUNCATE | \ 119 LANDLOCK_ACCESS_FS_IOCTL_DEV | \ 120 LANDLOCK_ACCESS_FS_RESOLVE_UNIX) 121 122 /* clang-format on */ 123 124 static int populate_ruleset_fs(const char *const env_var, const int ruleset_fd, 125 const __u64 allowed_access, __u32 flags) 126 { 127 int num_paths, i, ret = 1; 128 char *env_path_name; 129 const char **path_list = NULL; 130 struct landlock_path_beneath_attr path_beneath = { 131 .parent_fd = -1, 132 }; 133 134 env_path_name = getenv(env_var); 135 if (!env_path_name) { 136 /* Prevents users to forget a setting. */ 137 fprintf(stderr, "Missing environment variable %s\n", env_var); 138 return 1; 139 } 140 env_path_name = strdup(env_path_name); 141 unsetenv(env_var); 142 num_paths = parse_path(env_path_name, &path_list); 143 if (num_paths < 0) { 144 fprintf(stderr, "Failed to allocate memory\n"); 145 goto out_free_name; 146 } 147 if (num_paths == 1 && path_list[0][0] == '\0') { 148 /* 149 * Allows to not use all possible restrictions (e.g. use 150 * LL_FS_RO without LL_FS_RW). 151 */ 152 ret = 0; 153 goto out_free_name; 154 } 155 156 for (i = 0; i < num_paths; i++) { 157 struct stat statbuf; 158 159 path_beneath.parent_fd = open(path_list[i], O_PATH | O_CLOEXEC); 160 if (path_beneath.parent_fd < 0) { 161 fprintf(stderr, "Failed to open \"%s\": %s\n", 162 path_list[i], strerror(errno)); 163 continue; 164 } 165 if (fstat(path_beneath.parent_fd, &statbuf)) { 166 fprintf(stderr, "Failed to stat \"%s\": %s\n", 167 path_list[i], strerror(errno)); 168 close(path_beneath.parent_fd); 169 goto out_free_name; 170 } 171 path_beneath.allowed_access = allowed_access; 172 if (!S_ISDIR(statbuf.st_mode)) 173 path_beneath.allowed_access &= ACCESS_FILE; 174 if (landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH, 175 &path_beneath, flags)) { 176 fprintf(stderr, 177 "Failed to update the ruleset with \"%s\": %s\n", 178 path_list[i], strerror(errno)); 179 close(path_beneath.parent_fd); 180 goto out_free_name; 181 } 182 close(path_beneath.parent_fd); 183 } 184 ret = 0; 185 186 out_free_name: 187 free(path_list); 188 free(env_path_name); 189 return ret; 190 } 191 192 static int populate_ruleset_net(const char *const env_var, const int ruleset_fd, 193 const __u64 allowed_access, __u32 flags) 194 { 195 int ret = 1; 196 char *env_port_name, *env_port_name_next, *strport; 197 struct landlock_net_port_attr net_port = { 198 .allowed_access = allowed_access, 199 }; 200 201 env_port_name = getenv(env_var); 202 if (!env_port_name) 203 return 0; 204 env_port_name = strdup(env_port_name); 205 unsetenv(env_var); 206 207 env_port_name_next = env_port_name; 208 while ((strport = strsep(&env_port_name_next, ENV_DELIMITER))) { 209 __u64 port; 210 211 if (strcmp(strport, "") == 0) 212 continue; 213 214 if (str2num(strport, &port)) { 215 fprintf(stderr, "Failed to parse port at \"%s\"\n", 216 strport); 217 goto out_free_name; 218 } 219 net_port.port = port; 220 if (landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_PORT, 221 &net_port, flags)) { 222 fprintf(stderr, 223 "Failed to update the ruleset with port \"%llu\": %s\n", 224 net_port.port, strerror(errno)); 225 goto out_free_name; 226 } 227 } 228 ret = 0; 229 230 out_free_name: 231 free(env_port_name); 232 return ret; 233 } 234 235 /* Returns true on error, false otherwise. */ 236 static bool check_ruleset_scope(const char *const env_var, 237 struct landlock_ruleset_attr *ruleset_attr) 238 { 239 char *env_type_scope, *env_type_scope_next, *ipc_scoping_name; 240 bool error = false; 241 bool abstract_scoping = false; 242 bool signal_scoping = false; 243 244 /* Scoping is not supported by Landlock ABI */ 245 if (!(ruleset_attr->scoped & 246 (LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET | LANDLOCK_SCOPE_SIGNAL))) 247 goto out_unset; 248 249 env_type_scope = getenv(env_var); 250 /* Scoping is not supported by the user */ 251 if (!env_type_scope || strcmp("", env_type_scope) == 0) 252 goto out_unset; 253 254 env_type_scope = strdup(env_type_scope); 255 env_type_scope_next = env_type_scope; 256 while ((ipc_scoping_name = 257 strsep(&env_type_scope_next, ENV_DELIMITER))) { 258 if (strcmp("a", ipc_scoping_name) == 0 && !abstract_scoping) { 259 abstract_scoping = true; 260 } else if (strcmp("s", ipc_scoping_name) == 0 && 261 !signal_scoping) { 262 signal_scoping = true; 263 } else { 264 fprintf(stderr, "Unknown or duplicate scope \"%s\"\n", 265 ipc_scoping_name); 266 error = true; 267 goto out_free_name; 268 } 269 } 270 271 out_free_name: 272 free(env_type_scope); 273 274 out_unset: 275 if (!abstract_scoping) 276 ruleset_attr->scoped &= ~LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET; 277 if (!signal_scoping) 278 ruleset_attr->scoped &= ~LANDLOCK_SCOPE_SIGNAL; 279 280 unsetenv(env_var); 281 return error; 282 } 283 284 /* clang-format off */ 285 286 #define ACCESS_FS_ROUGHLY_READ ( \ 287 LANDLOCK_ACCESS_FS_EXECUTE | \ 288 LANDLOCK_ACCESS_FS_READ_FILE | \ 289 LANDLOCK_ACCESS_FS_READ_DIR) 290 291 #define ACCESS_FS_ROUGHLY_WRITE ( \ 292 LANDLOCK_ACCESS_FS_WRITE_FILE | \ 293 LANDLOCK_ACCESS_FS_REMOVE_DIR | \ 294 LANDLOCK_ACCESS_FS_REMOVE_FILE | \ 295 LANDLOCK_ACCESS_FS_MAKE_CHAR | \ 296 LANDLOCK_ACCESS_FS_MAKE_DIR | \ 297 LANDLOCK_ACCESS_FS_MAKE_REG | \ 298 LANDLOCK_ACCESS_FS_MAKE_SOCK | \ 299 LANDLOCK_ACCESS_FS_MAKE_FIFO | \ 300 LANDLOCK_ACCESS_FS_MAKE_BLOCK | \ 301 LANDLOCK_ACCESS_FS_MAKE_SYM | \ 302 LANDLOCK_ACCESS_FS_REFER | \ 303 LANDLOCK_ACCESS_FS_TRUNCATE | \ 304 LANDLOCK_ACCESS_FS_IOCTL_DEV | \ 305 LANDLOCK_ACCESS_FS_RESOLVE_UNIX) 306 307 /* clang-format on */ 308 309 /* 310 * Parses ENV_QUIET_ACCESS_NAME and sets the quiet_access_fs, quiet_access_net 311 * and quiet_scoped masks of @ruleset_attr accordingly. 312 */ 313 static int add_quiet_access(const char *const env_var, 314 struct landlock_ruleset_attr *const ruleset_attr) 315 { 316 char *env_quiet_access, *env_quiet_access_next, *str_access; 317 318 env_quiet_access = getenv(env_var); 319 if (!env_quiet_access) 320 return 0; 321 322 env_quiet_access = strdup(env_quiet_access); 323 env_quiet_access_next = env_quiet_access; 324 unsetenv(env_var); 325 326 while ((str_access = strsep(&env_quiet_access_next, ENV_DELIMITER))) { 327 if (strcmp(str_access, "") == 0) 328 continue; 329 else if (strcmp(str_access, "all") == 0) { 330 ruleset_attr->quiet_access_fs = 331 ruleset_attr->handled_access_fs; 332 ruleset_attr->quiet_access_net = 333 ruleset_attr->handled_access_net; 334 ruleset_attr->quiet_scoped = ruleset_attr->scoped; 335 } else if (strcmp(str_access, "read") == 0) 336 ruleset_attr->quiet_access_fs |= ACCESS_FS_ROUGHLY_READ; 337 else if (strcmp(str_access, "write") == 0) 338 ruleset_attr->quiet_access_fs |= 339 ACCESS_FS_ROUGHLY_WRITE; 340 else if (strcmp(str_access, "tcp_bind") == 0) 341 ruleset_attr->quiet_access_net |= 342 LANDLOCK_ACCESS_NET_BIND_TCP; 343 else if (strcmp(str_access, "tcp_connect") == 0) 344 ruleset_attr->quiet_access_net |= 345 LANDLOCK_ACCESS_NET_CONNECT_TCP; 346 else if (strcmp(str_access, "udp_bind") == 0) 347 ruleset_attr->quiet_access_net |= 348 LANDLOCK_ACCESS_NET_BIND_UDP; 349 else if (strcmp(str_access, "udp_connect") == 0) 350 ruleset_attr->quiet_access_net |= 351 LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP; 352 else if (strcmp(str_access, "abstract_unix_socket") == 0) 353 ruleset_attr->quiet_scoped |= 354 LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET; 355 else if (strcmp(str_access, "signal") == 0) 356 ruleset_attr->quiet_scoped |= LANDLOCK_SCOPE_SIGNAL; 357 else { 358 fprintf(stderr, "Unknown quiet access \"%s\"\n", 359 str_access); 360 free(env_quiet_access); 361 return -1; 362 } 363 } 364 365 free(env_quiet_access); 366 ruleset_attr->quiet_access_fs &= ruleset_attr->handled_access_fs; 367 ruleset_attr->quiet_access_net &= ruleset_attr->handled_access_net; 368 ruleset_attr->quiet_scoped &= ruleset_attr->scoped; 369 return 0; 370 } 371 372 #define LANDLOCK_ABI_LAST 11 373 374 #define XSTR(s) #s 375 #define STR(s) XSTR(s) 376 377 /* clang-format off */ 378 379 static const char help[] = 380 "usage: " ENV_FS_RO_NAME "=\"...\" " ENV_FS_RW_NAME "=\"...\" " 381 "[other environment variables] %1$s <cmd> [args]...\n" 382 "\n" 383 "Execute the given command in a restricted environment.\n" 384 "Multi-valued settings (lists of ports, paths, scopes) are colon-delimited.\n" 385 "\n" 386 "Mandatory settings:\n" 387 "* " ENV_FS_RO_NAME ": paths allowed to be used in a read-only way\n" 388 "* " ENV_FS_RW_NAME ": paths allowed to be used in a read-write way\n" 389 "\n" 390 "Optional settings (when not set, their associated access check " 391 "is always allowed, which is different from an empty string which " 392 "means an empty list):\n" 393 "* " ENV_TCP_BIND_NAME ": ports allowed to bind (server)\n" 394 "* " ENV_TCP_CONNECT_NAME ": ports allowed to connect (client)\n" 395 "* " ENV_UDP_BIND_NAME ": local UDP ports allowed to bind (server: " 396 "prepare to receive on port / client: set as source port)\n" 397 "* " ENV_UDP_CONNECT_SEND_NAME ": remote UDP ports allowed to connect " 398 "or send to (client: use as destination port / server: receive only from it)\n" 399 "(caution: sending requires being able to bind to a local source port)\n" 400 "* " ENV_SCOPED_NAME ": actions denied on the outside of the landlock domain\n" 401 " - \"a\" to restrict opening abstract unix sockets\n" 402 " - \"s\" to restrict sending signals\n" 403 "\n" 404 "A sandboxer should not log denied access requests to avoid spamming logs, " 405 "but to test audit we can set " ENV_FORCE_LOG_NAME "=1\n" 406 ENV_FS_QUIET_NAME " and " ENV_NET_QUIET_NAME ", both optional, can then be used " 407 "to make access to some denied paths or network ports not trigger audit logging.\n" 408 ENV_QUIET_ACCESS_NAME " can be used to specify which accesses should be quieted " 409 "(required when " ENV_FS_QUIET_NAME " or " ENV_NET_QUIET_NAME " is set):\n" 410 " - \"all\" to quiet all of the accesses below\n" 411 " - \"read\" to quiet all file/dir read accesses\n" 412 " - \"write\" to quiet all file/dir write accesses\n" 413 " - \"tcp_bind\" to quiet tcp bind denials\n" 414 " - \"tcp_connect\" to quiet tcp connect denials\n" 415 " - \"udp_bind\" to quiet udp bind denials\n" 416 " - \"udp_connect\" to quiet udp connect / send denials\n" 417 " - \"abstract_unix_socket\" to quiet abstract unix socket denials\n" 418 " - \"signal\" to quiet signal denials\n" 419 "\n" 420 "Example:\n" 421 ENV_FS_RO_NAME "=\"${PATH}:/lib:/usr:/proc:/etc:/dev/urandom\" " 422 ENV_FS_RW_NAME "=\"/dev/null:/dev/full:/dev/zero:/dev/pts:/tmp\" " 423 ENV_TCP_BIND_NAME "=\"9418\" " 424 ENV_TCP_CONNECT_NAME "=\"80:443\" " 425 ENV_UDP_CONNECT_SEND_NAME "=\"53\" " 426 ENV_SCOPED_NAME "=\"a:s\" " 427 "%1$s bash -i\n" 428 "\n" 429 "This sandboxer can use Landlock features up to ABI version " 430 STR(LANDLOCK_ABI_LAST) ".\n"; 431 432 /* clang-format on */ 433 434 int main(const int argc, char *const argv[], char *const *const envp) 435 { 436 const char *cmd_path; 437 char *const *cmd_argv; 438 int ruleset_fd, abi; 439 char *env_port_name, *env_force_log; 440 __u64 access_fs_ro = ACCESS_FS_ROUGHLY_READ, 441 access_fs_rw = ACCESS_FS_ROUGHLY_READ | ACCESS_FS_ROUGHLY_WRITE; 442 443 struct landlock_ruleset_attr ruleset_attr = { 444 .handled_access_fs = access_fs_rw, 445 .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP | 446 LANDLOCK_ACCESS_NET_CONNECT_TCP | 447 LANDLOCK_ACCESS_NET_BIND_UDP | 448 LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP, 449 .scoped = LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET | 450 LANDLOCK_SCOPE_SIGNAL, 451 .quiet_access_fs = 0, 452 .quiet_access_net = 0, 453 .quiet_scoped = 0, 454 }; 455 bool quiet_supported = true; 456 int supported_restrict_flags = LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON | 457 LANDLOCK_RESTRICT_SELF_NO_NEW_PRIVS; 458 int set_restrict_flags = LANDLOCK_RESTRICT_SELF_NO_NEW_PRIVS; 459 460 if (argc < 2) { 461 fprintf(stderr, help, argv[0]); 462 return 1; 463 } 464 465 abi = landlock_create_ruleset(NULL, 0, LANDLOCK_CREATE_RULESET_VERSION); 466 if (abi < 0) { 467 const int err = errno; 468 469 perror("Failed to check Landlock compatibility"); 470 switch (err) { 471 case ENOSYS: 472 fprintf(stderr, 473 "Hint: Landlock is not supported by the current kernel. " 474 "To support it, build the kernel with " 475 "CONFIG_SECURITY_LANDLOCK=y and prepend " 476 "\"landlock,\" to the content of CONFIG_LSM.\n"); 477 break; 478 case EOPNOTSUPP: 479 fprintf(stderr, 480 "Hint: Landlock is currently disabled. " 481 "It can be enabled in the kernel configuration by " 482 "prepending \"landlock,\" to the content of CONFIG_LSM, " 483 "or at boot time by setting the same content to the " 484 "\"lsm\" kernel parameter.\n"); 485 break; 486 } 487 return 1; 488 } 489 490 /* Best-effort security. */ 491 switch (abi) { 492 case 1: 493 /* 494 * Removes LANDLOCK_ACCESS_FS_REFER for ABI < 2 495 * 496 * Note: The "refer" operations (file renaming and linking 497 * across different directories) are always forbidden when using 498 * Landlock with ABI 1. 499 * 500 * If only ABI 1 is available, this sandboxer knowingly forbids 501 * refer operations. 502 * 503 * If a program *needs* to do refer operations after enabling 504 * Landlock, it can not use Landlock at ABI level 1. To be 505 * compatible with different kernel versions, such programs 506 * should then fall back to not restrict themselves at all if 507 * the running kernel only supports ABI 1. 508 */ 509 ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_REFER; 510 __attribute__((fallthrough)); 511 case 2: 512 /* Removes LANDLOCK_ACCESS_FS_TRUNCATE for ABI < 3 */ 513 ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_TRUNCATE; 514 __attribute__((fallthrough)); 515 case 3: 516 /* Removes network support for ABI < 4 */ 517 ruleset_attr.handled_access_net &= 518 ~(LANDLOCK_ACCESS_NET_BIND_TCP | 519 LANDLOCK_ACCESS_NET_CONNECT_TCP); 520 __attribute__((fallthrough)); 521 case 4: 522 /* Removes LANDLOCK_ACCESS_FS_IOCTL_DEV for ABI < 5 */ 523 ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_IOCTL_DEV; 524 525 __attribute__((fallthrough)); 526 case 5: 527 /* Removes LANDLOCK_SCOPE_* for ABI < 6 */ 528 ruleset_attr.scoped &= ~(LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET | 529 LANDLOCK_SCOPE_SIGNAL); 530 __attribute__((fallthrough)); 531 case 6: 532 /* Removes LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON for ABI < 7 */ 533 supported_restrict_flags &= 534 ~LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON; 535 __attribute__((fallthrough)); 536 case 7: 537 case 8: 538 /* Removes LANDLOCK_ACCESS_FS_RESOLVE_UNIX for ABI < 9 */ 539 ruleset_attr.handled_access_fs &= 540 ~LANDLOCK_ACCESS_FS_RESOLVE_UNIX; 541 __attribute__((fallthrough)); 542 case 9: 543 /* Removes UDP support for ABI < 10 */ 544 ruleset_attr.handled_access_net &= 545 ~(LANDLOCK_ACCESS_NET_BIND_UDP | 546 LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP); 547 /* Removes quiet flags for ABI < 10 later on. */ 548 quiet_supported = false; 549 __attribute__((fallthrough)); 550 case 10: 551 /* Removes LANDLOCK_RESTRICT_SELF_NO_NEW_PRIVS for ABI < 11 */ 552 supported_restrict_flags &= 553 ~LANDLOCK_RESTRICT_SELF_NO_NEW_PRIVS; 554 set_restrict_flags &= ~LANDLOCK_RESTRICT_SELF_NO_NEW_PRIVS; 555 556 /* Must be printed for any ABI < LANDLOCK_ABI_LAST. */ 557 fprintf(stderr, 558 "Hint: You should update the running kernel " 559 "to leverage Landlock features " 560 "provided by ABI version %d (instead of %d).\n", 561 LANDLOCK_ABI_LAST, abi); 562 __attribute__((fallthrough)); 563 case LANDLOCK_ABI_LAST: 564 break; 565 default: 566 fprintf(stderr, 567 "Hint: You should update this sandboxer " 568 "to leverage Landlock features " 569 "provided by ABI version %d (instead of %d).\n", 570 abi, LANDLOCK_ABI_LAST); 571 } 572 access_fs_ro &= ruleset_attr.handled_access_fs; 573 access_fs_rw &= ruleset_attr.handled_access_fs; 574 575 /* Removes bind access attribute if not supported by a user. */ 576 env_port_name = getenv(ENV_TCP_BIND_NAME); 577 if (!env_port_name) { 578 ruleset_attr.handled_access_net &= 579 ~LANDLOCK_ACCESS_NET_BIND_TCP; 580 } 581 /* Removes connect access attribute if not supported by a user. */ 582 env_port_name = getenv(ENV_TCP_CONNECT_NAME); 583 if (!env_port_name) { 584 ruleset_attr.handled_access_net &= 585 ~LANDLOCK_ACCESS_NET_CONNECT_TCP; 586 } 587 /* Removes UDP bind access control if not supported by a user. */ 588 env_port_name = getenv(ENV_UDP_BIND_NAME); 589 if (!env_port_name) { 590 ruleset_attr.handled_access_net &= 591 ~LANDLOCK_ACCESS_NET_BIND_UDP; 592 } 593 /* Removes UDP connect/send access control if not supported by a user. */ 594 env_port_name = getenv(ENV_UDP_CONNECT_SEND_NAME); 595 if (!env_port_name) { 596 ruleset_attr.handled_access_net &= 597 ~LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP; 598 } 599 600 if (check_ruleset_scope(ENV_SCOPED_NAME, &ruleset_attr)) 601 return 1; 602 603 /* Enables optional logs. */ 604 env_force_log = getenv(ENV_FORCE_LOG_NAME); 605 if (env_force_log) { 606 if (strcmp(env_force_log, "1") != 0) { 607 fprintf(stderr, "Unknown value for " ENV_FORCE_LOG_NAME 608 " (only \"1\" is handled)\n"); 609 return 1; 610 } 611 if (!(supported_restrict_flags & 612 LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON)) { 613 fprintf(stderr, 614 "Audit logs not supported by current kernel\n"); 615 return 1; 616 } 617 set_restrict_flags |= LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON; 618 unsetenv(ENV_FORCE_LOG_NAME); 619 } 620 621 /* Set the quiet access masks. */ 622 if (quiet_supported) { 623 if ((getenv(ENV_FS_QUIET_NAME) || getenv(ENV_NET_QUIET_NAME)) && 624 !getenv(ENV_QUIET_ACCESS_NAME)) { 625 fprintf(stderr, 626 "%s must be set (e.g. to \"all\") when %s or %s is used\n", 627 ENV_QUIET_ACCESS_NAME, ENV_FS_QUIET_NAME, 628 ENV_NET_QUIET_NAME); 629 return 1; 630 } 631 if (add_quiet_access(ENV_QUIET_ACCESS_NAME, &ruleset_attr)) 632 return 1; 633 } else if (getenv(ENV_FS_QUIET_NAME) || getenv(ENV_NET_QUIET_NAME) || 634 getenv(ENV_QUIET_ACCESS_NAME)) { 635 fprintf(stderr, 636 "Quiet flags not supported by current kernel\n"); 637 return 1; 638 } 639 640 ruleset_fd = 641 landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); 642 if (ruleset_fd < 0) { 643 perror("Failed to create a ruleset"); 644 return 1; 645 } 646 647 if (populate_ruleset_fs(ENV_FS_RO_NAME, ruleset_fd, access_fs_ro, 0)) 648 goto err_close_ruleset; 649 if (populate_ruleset_fs(ENV_FS_RW_NAME, ruleset_fd, access_fs_rw, 0)) 650 goto err_close_ruleset; 651 652 /* Don't require this env to be present. */ 653 if (quiet_supported && getenv(ENV_FS_QUIET_NAME)) { 654 if (populate_ruleset_fs(ENV_FS_QUIET_NAME, ruleset_fd, 0, 655 LANDLOCK_ADD_RULE_QUIET)) 656 goto err_close_ruleset; 657 } 658 659 if (populate_ruleset_net(ENV_TCP_BIND_NAME, ruleset_fd, 660 LANDLOCK_ACCESS_NET_BIND_TCP, 0)) { 661 goto err_close_ruleset; 662 } 663 if (populate_ruleset_net(ENV_TCP_CONNECT_NAME, ruleset_fd, 664 LANDLOCK_ACCESS_NET_CONNECT_TCP, 0)) { 665 goto err_close_ruleset; 666 } 667 if (populate_ruleset_net(ENV_UDP_BIND_NAME, ruleset_fd, 668 LANDLOCK_ACCESS_NET_BIND_UDP, 0)) { 669 goto err_close_ruleset; 670 } 671 if (populate_ruleset_net(ENV_UDP_CONNECT_SEND_NAME, ruleset_fd, 672 LANDLOCK_ACCESS_NET_CONNECT_SEND_UDP, 0)) { 673 goto err_close_ruleset; 674 } 675 676 if (quiet_supported) { 677 if (populate_ruleset_net(ENV_NET_QUIET_NAME, ruleset_fd, 0, 678 LANDLOCK_ADD_RULE_QUIET)) { 679 goto err_close_ruleset; 680 } 681 } 682 683 if (!(set_restrict_flags & LANDLOCK_RESTRICT_SELF_NO_NEW_PRIVS) && 684 prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { 685 perror("Failed to restrict privileges"); 686 goto err_close_ruleset; 687 } 688 if (landlock_restrict_self(ruleset_fd, set_restrict_flags)) { 689 perror("Failed to enforce ruleset"); 690 goto err_close_ruleset; 691 } 692 close(ruleset_fd); 693 694 cmd_path = argv[1]; 695 cmd_argv = argv + 1; 696 fprintf(stderr, "Executing the sandboxed command...\n"); 697 execvpe(cmd_path, cmd_argv, envp); 698 fprintf(stderr, "Failed to execute \"%s\": %s\n", cmd_path, 699 strerror(errno)); 700 fprintf(stderr, "Hint: access to the binary, the interpreter or " 701 "shared libraries may be denied.\n"); 702 return 1; 703 704 err_close_ruleset: 705 close(ruleset_fd); 706 return 1; 707 } 708