1 /*- 2 * Copyright (c) 1999-2002, 2006, 2009 Robert N. M. Watson 3 * Copyright (c) 2001 Ilmar S. Habibulin 4 * Copyright (c) 2001-2005 Networks Associates Technology, Inc. 5 * Copyright (c) 2005-2006 SPARTA, Inc. 6 * Copyright (c) 2008-2009 Apple Inc. 7 * All rights reserved. 8 * 9 * This software was developed by Robert Watson and Ilmar Habibulin for the 10 * TrustedBSD Project. 11 * 12 * This software was developed for the FreeBSD Project in part by Network 13 * Associates Laboratories, the Security Research Division of Network 14 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), 15 * as part of the DARPA CHATS research program. 16 * 17 * This software was enhanced by SPARTA ISSO under SPAWAR contract 18 * N66001-04-C-6019 ("SEFOS"). 19 * 20 * This software was developed at the University of Cambridge Computer 21 * Laboratory with support from a grant from Google, Inc. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the above copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 35 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 42 * SUCH DAMAGE. 43 */ 44 45 /*- 46 * Framework for extensible kernel access control. This file contains core 47 * kernel infrastructure for the TrustedBSD MAC Framework, including policy 48 * registration, versioning, locking, error composition operator, and system 49 * calls. 50 * 51 * The MAC Framework implements three programming interfaces: 52 * 53 * - The kernel MAC interface, defined in mac_framework.h, and invoked 54 * throughout the kernel to request security decisions, notify of security 55 * related events, etc. 56 * 57 * - The MAC policy module interface, defined in mac_policy.h, which is 58 * implemented by MAC policy modules and invoked by the MAC Framework to 59 * forward kernel security requests and notifications to policy modules. 60 * 61 * - The user MAC API, defined in mac.h, which allows user programs to query 62 * and set label state on objects. 63 * 64 * The majority of the MAC Framework implementation may be found in 65 * src/sys/security/mac. Sample policy modules may be found in 66 * src/sys/security/mac_*. 67 */ 68 69 #include "opt_mac.h" 70 71 #include <sys/cdefs.h> 72 __FBSDID("$FreeBSD$"); 73 74 #include <sys/param.h> 75 #include <sys/systm.h> 76 #include <sys/condvar.h> 77 #include <sys/kernel.h> 78 #include <sys/lock.h> 79 #include <sys/mac.h> 80 #include <sys/module.h> 81 #include <sys/rmlock.h> 82 #include <sys/sdt.h> 83 #include <sys/sx.h> 84 #include <sys/sysctl.h> 85 86 #include <security/mac/mac_framework.h> 87 #include <security/mac/mac_internal.h> 88 #include <security/mac/mac_policy.h> 89 90 /* 91 * DTrace SDT providers for MAC. 92 */ 93 SDT_PROVIDER_DEFINE(mac); 94 SDT_PROVIDER_DEFINE(mac_framework); 95 96 SDT_PROBE_DEFINE2(mac, , policy, modevent, "int", 97 "struct mac_policy_conf *"); 98 SDT_PROBE_DEFINE1(mac, , policy, register, 99 "struct mac_policy_conf *"); 100 SDT_PROBE_DEFINE1(mac, , policy, unregister, 101 "struct mac_policy_conf *"); 102 103 /* 104 * Root sysctl node for all MAC and MAC policy controls. 105 */ 106 SYSCTL_NODE(_security, OID_AUTO, mac, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 107 "TrustedBSD MAC policy controls"); 108 109 /* 110 * Declare that the kernel provides MAC support, version 3 (FreeBSD 7.x). 111 * This permits modules to refuse to be loaded if the necessary support isn't 112 * present, even if it's pre-boot. 113 */ 114 MODULE_VERSION(kernel_mac_support, MAC_VERSION); 115 116 static unsigned int mac_version = MAC_VERSION; 117 SYSCTL_UINT(_security_mac, OID_AUTO, version, CTLFLAG_RD, &mac_version, 0, 118 ""); 119 120 /* 121 * Flags for inlined checks. Note this would be best hotpatched at runtime. 122 * The following is a band-aid. 123 * 124 * Use FPFLAG for hooks running in commonly executed paths and FPFLAG_RARE 125 * for the rest. 126 */ 127 #define FPFLAG(f) \ 128 bool __read_frequently mac_##f##_fp_flag 129 130 #define FPFLAG_RARE(f) \ 131 bool __read_mostly mac_##f##_fp_flag 132 133 FPFLAG(priv_check); 134 FPFLAG(priv_grant); 135 FPFLAG(vnode_check_lookup); 136 FPFLAG(vnode_check_open); 137 FPFLAG(vnode_check_stat); 138 FPFLAG(vnode_check_read); 139 FPFLAG(vnode_check_write); 140 FPFLAG(vnode_check_mmap); 141 FPFLAG_RARE(vnode_check_poll); 142 FPFLAG_RARE(vnode_check_rename_from); 143 144 #undef FPFLAG 145 #undef FPFLAG_RARE 146 147 /* 148 * Labels consist of a indexed set of "slots", which are allocated policies 149 * as required. The MAC Framework maintains a bitmask of slots allocated so 150 * far to prevent reuse. Slots cannot be reused, as the MAC Framework 151 * guarantees that newly allocated slots in labels will be NULL unless 152 * otherwise initialized, and because we do not have a mechanism to garbage 153 * collect slots on policy unload. As labeled policies tend to be statically 154 * loaded during boot, and not frequently unloaded and reloaded, this is not 155 * generally an issue. 156 */ 157 #if MAC_MAX_SLOTS > 32 158 #error "MAC_MAX_SLOTS too large" 159 #endif 160 161 static unsigned int mac_max_slots = MAC_MAX_SLOTS; 162 static unsigned int mac_slot_offsets_free = (1 << MAC_MAX_SLOTS) - 1; 163 SYSCTL_UINT(_security_mac, OID_AUTO, max_slots, CTLFLAG_RD, &mac_max_slots, 164 0, ""); 165 166 /* 167 * Has the kernel started generating labeled objects yet? All read/write 168 * access to this variable is serialized during the boot process. Following 169 * the end of serialization, we don't update this flag; no locking. 170 */ 171 static int mac_late = 0; 172 173 /* 174 * Each policy declares a mask of object types requiring labels to be 175 * allocated for them. For convenience, we combine and cache the bitwise or 176 * of the per-policy object flags to track whether we will allocate a label 177 * for an object type at run-time. 178 */ 179 uint64_t mac_labeled; 180 SYSCTL_UQUAD(_security_mac, OID_AUTO, labeled, CTLFLAG_RD, &mac_labeled, 0, 181 "Mask of object types being labeled"); 182 183 MALLOC_DEFINE(M_MACTEMP, "mactemp", "MAC temporary label storage"); 184 185 /* 186 * MAC policy modules are placed in one of two lists: mac_static_policy_list, 187 * for policies that are loaded early and cannot be unloaded, and 188 * mac_policy_list, which holds policies either loaded later in the boot 189 * cycle or that may be unloaded. The static policy list does not require 190 * locks to iterate over, but the dynamic list requires synchronization. 191 * Support for dynamic policy loading can be compiled out using the 192 * MAC_STATIC kernel option. 193 * 194 * The dynamic policy list is protected by two locks: modifying the list 195 * requires both locks to be held exclusively. One of the locks, 196 * mac_policy_rm, is acquired over policy entry points that will never sleep; 197 * the other, mac_policy_rms, is acquired over policy entry points that may 198 * sleep. The former category will be used when kernel locks may be held 199 * over calls to the MAC Framework, during network processing in ithreads, 200 * etc. The latter will tend to involve potentially blocking memory 201 * allocations, extended attribute I/O, etc. 202 */ 203 #ifndef MAC_STATIC 204 static struct rmlock mac_policy_rm; /* Non-sleeping entry points. */ 205 static struct rmslock mac_policy_rms; /* Sleeping entry points. */ 206 #endif 207 208 struct mac_policy_list_head mac_policy_list; 209 struct mac_policy_list_head mac_static_policy_list; 210 u_int mac_policy_count; /* Registered policy count. */ 211 212 static void mac_policy_xlock(void); 213 static void mac_policy_xlock_assert(void); 214 static void mac_policy_xunlock(void); 215 216 void 217 mac_policy_slock_nosleep(struct rm_priotracker *tracker) 218 { 219 220 #ifndef MAC_STATIC 221 if (!mac_late) 222 return; 223 224 rm_rlock(&mac_policy_rm, tracker); 225 #endif 226 } 227 228 void 229 mac_policy_slock_sleep(void) 230 { 231 232 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 233 "mac_policy_slock_sleep"); 234 235 #ifndef MAC_STATIC 236 if (!mac_late) 237 return; 238 239 rms_rlock(&mac_policy_rms); 240 #endif 241 } 242 243 void 244 mac_policy_sunlock_nosleep(struct rm_priotracker *tracker) 245 { 246 247 #ifndef MAC_STATIC 248 if (!mac_late) 249 return; 250 251 rm_runlock(&mac_policy_rm, tracker); 252 #endif 253 } 254 255 void 256 mac_policy_sunlock_sleep(void) 257 { 258 259 #ifndef MAC_STATIC 260 if (!mac_late) 261 return; 262 263 rms_runlock(&mac_policy_rms); 264 #endif 265 } 266 267 static void 268 mac_policy_xlock(void) 269 { 270 271 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 272 "mac_policy_xlock()"); 273 274 #ifndef MAC_STATIC 275 if (!mac_late) 276 return; 277 278 rms_wlock(&mac_policy_rms); 279 rm_wlock(&mac_policy_rm); 280 #endif 281 } 282 283 static void 284 mac_policy_xunlock(void) 285 { 286 287 #ifndef MAC_STATIC 288 if (!mac_late) 289 return; 290 291 rm_wunlock(&mac_policy_rm); 292 rms_wunlock(&mac_policy_rms); 293 #endif 294 } 295 296 static void 297 mac_policy_xlock_assert(void) 298 { 299 300 #ifndef MAC_STATIC 301 if (!mac_late) 302 return; 303 304 rm_assert(&mac_policy_rm, RA_WLOCKED); 305 #endif 306 } 307 308 /* 309 * Initialize the MAC subsystem, including appropriate SMP locks. 310 */ 311 static void 312 mac_init(void) 313 { 314 315 LIST_INIT(&mac_static_policy_list); 316 LIST_INIT(&mac_policy_list); 317 mac_labelzone_init(); 318 319 #ifndef MAC_STATIC 320 rm_init_flags(&mac_policy_rm, "mac_policy_rm", RM_NOWITNESS | 321 RM_RECURSE); 322 rms_init(&mac_policy_rms, "mac_policy_rms"); 323 #endif 324 } 325 326 /* 327 * For the purposes of modules that want to know if they were loaded "early", 328 * set the mac_late flag once we've processed modules either linked into the 329 * kernel, or loaded before the kernel startup. 330 */ 331 static void 332 mac_late_init(void) 333 { 334 335 mac_late = 1; 336 } 337 338 /* 339 * Given a policy, derive from its set of non-NULL label init methods what 340 * object types the policy is interested in. 341 */ 342 static uint64_t 343 mac_policy_getlabeled(struct mac_policy_conf *mpc) 344 { 345 uint64_t labeled; 346 347 #define MPC_FLAG(method, flag) \ 348 if (mpc->mpc_ops->mpo_ ## method != NULL) \ 349 labeled |= (flag); \ 350 351 labeled = 0; 352 MPC_FLAG(cred_init_label, MPC_OBJECT_CRED); 353 MPC_FLAG(proc_init_label, MPC_OBJECT_PROC); 354 MPC_FLAG(vnode_init_label, MPC_OBJECT_VNODE); 355 MPC_FLAG(inpcb_init_label, MPC_OBJECT_INPCB); 356 MPC_FLAG(socket_init_label, MPC_OBJECT_SOCKET); 357 MPC_FLAG(devfs_init_label, MPC_OBJECT_DEVFS); 358 MPC_FLAG(mbuf_init_label, MPC_OBJECT_MBUF); 359 MPC_FLAG(ipq_init_label, MPC_OBJECT_IPQ); 360 MPC_FLAG(ifnet_init_label, MPC_OBJECT_IFNET); 361 MPC_FLAG(bpfdesc_init_label, MPC_OBJECT_BPFDESC); 362 MPC_FLAG(pipe_init_label, MPC_OBJECT_PIPE); 363 MPC_FLAG(mount_init_label, MPC_OBJECT_MOUNT); 364 MPC_FLAG(posixsem_init_label, MPC_OBJECT_POSIXSEM); 365 MPC_FLAG(posixshm_init_label, MPC_OBJECT_POSIXSHM); 366 MPC_FLAG(sysvmsg_init_label, MPC_OBJECT_SYSVMSG); 367 MPC_FLAG(sysvmsq_init_label, MPC_OBJECT_SYSVMSQ); 368 MPC_FLAG(sysvsem_init_label, MPC_OBJECT_SYSVSEM); 369 MPC_FLAG(sysvshm_init_label, MPC_OBJECT_SYSVSHM); 370 MPC_FLAG(syncache_init_label, MPC_OBJECT_SYNCACHE); 371 MPC_FLAG(ip6q_init_label, MPC_OBJECT_IP6Q); 372 373 #undef MPC_FLAG 374 return (labeled); 375 } 376 377 /* 378 * When policies are loaded or unloaded, walk the list of registered policies 379 * and built mac_labeled, a bitmask representing the union of all objects 380 * requiring labels across all policies. 381 */ 382 static void 383 mac_policy_update(void) 384 { 385 struct mac_policy_conf *mpc; 386 387 mac_policy_xlock_assert(); 388 389 mac_labeled = 0; 390 mac_policy_count = 0; 391 LIST_FOREACH(mpc, &mac_static_policy_list, mpc_list) { 392 mac_labeled |= mac_policy_getlabeled(mpc); 393 mac_policy_count++; 394 } 395 LIST_FOREACH(mpc, &mac_policy_list, mpc_list) { 396 mac_labeled |= mac_policy_getlabeled(mpc); 397 mac_policy_count++; 398 } 399 } 400 401 /* 402 * There are frequently used code paths which check for rarely installed 403 * policies. Gross hack below enables doing it in a cheap manner. 404 */ 405 406 #define FPO(f) (offsetof(struct mac_policy_ops, mpo_##f) / sizeof(uintptr_t)) 407 408 struct mac_policy_fastpath_elem { 409 int count; 410 bool *flag; 411 size_t offset; 412 }; 413 414 struct mac_policy_fastpath_elem mac_policy_fastpath_array[] = { 415 { .offset = FPO(priv_check), .flag = &mac_priv_check_fp_flag }, 416 { .offset = FPO(priv_grant), .flag = &mac_priv_grant_fp_flag }, 417 { .offset = FPO(vnode_check_lookup), 418 .flag = &mac_vnode_check_lookup_fp_flag }, 419 { .offset = FPO(vnode_check_open), 420 .flag = &mac_vnode_check_open_fp_flag }, 421 { .offset = FPO(vnode_check_stat), 422 .flag = &mac_vnode_check_stat_fp_flag }, 423 { .offset = FPO(vnode_check_read), 424 .flag = &mac_vnode_check_read_fp_flag }, 425 { .offset = FPO(vnode_check_write), 426 .flag = &mac_vnode_check_write_fp_flag }, 427 { .offset = FPO(vnode_check_mmap), 428 .flag = &mac_vnode_check_mmap_fp_flag }, 429 { .offset = FPO(vnode_check_poll), 430 .flag = &mac_vnode_check_poll_fp_flag }, 431 { .offset = FPO(vnode_check_rename_from), 432 .flag = &mac_vnode_check_rename_from_fp_flag }, 433 }; 434 435 static void 436 mac_policy_fastpath_enable(struct mac_policy_fastpath_elem *mpfe) 437 { 438 439 MPASS(mpfe->count >= 0); 440 mpfe->count++; 441 if (mpfe->count == 1) { 442 MPASS(*mpfe->flag == false); 443 *mpfe->flag = true; 444 } 445 } 446 447 static void 448 mac_policy_fastpath_disable(struct mac_policy_fastpath_elem *mpfe) 449 { 450 451 MPASS(mpfe->count >= 1); 452 mpfe->count--; 453 if (mpfe->count == 0) { 454 MPASS(*mpfe->flag == true); 455 *mpfe->flag = false; 456 } 457 } 458 459 static void 460 mac_policy_fastpath_register(struct mac_policy_conf *mpc) 461 { 462 struct mac_policy_fastpath_elem *mpfe; 463 uintptr_t **ops; 464 int i; 465 466 mac_policy_xlock_assert(); 467 468 ops = (uintptr_t **)mpc->mpc_ops; 469 for (i = 0; i < nitems(mac_policy_fastpath_array); i++) { 470 mpfe = &mac_policy_fastpath_array[i]; 471 if (ops[mpfe->offset] != NULL) 472 mac_policy_fastpath_enable(mpfe); 473 } 474 } 475 476 static void 477 mac_policy_fastpath_unregister(struct mac_policy_conf *mpc) 478 { 479 struct mac_policy_fastpath_elem *mpfe; 480 uintptr_t **ops; 481 int i; 482 483 mac_policy_xlock_assert(); 484 485 ops = (uintptr_t **)mpc->mpc_ops; 486 for (i = 0; i < nitems(mac_policy_fastpath_array); i++) { 487 mpfe = &mac_policy_fastpath_array[i]; 488 if (ops[mpfe->offset] != NULL) 489 mac_policy_fastpath_disable(mpfe); 490 } 491 } 492 493 #undef FPO 494 495 static int 496 mac_policy_register(struct mac_policy_conf *mpc) 497 { 498 struct mac_policy_conf *tmpc; 499 int error, slot, static_entry; 500 501 error = 0; 502 503 /* 504 * We don't technically need exclusive access while !mac_late, but 505 * hold it for assertion consistency. 506 */ 507 mac_policy_xlock(); 508 509 /* 510 * If the module can potentially be unloaded, or we're loading late, 511 * we have to stick it in the non-static list and pay an extra 512 * performance overhead. Otherwise, we can pay a light locking cost 513 * and stick it in the static list. 514 */ 515 static_entry = (!mac_late && 516 !(mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_UNLOADOK)); 517 518 if (static_entry) { 519 LIST_FOREACH(tmpc, &mac_static_policy_list, mpc_list) { 520 if (strcmp(tmpc->mpc_name, mpc->mpc_name) == 0) { 521 error = EEXIST; 522 goto out; 523 } 524 } 525 } else { 526 LIST_FOREACH(tmpc, &mac_policy_list, mpc_list) { 527 if (strcmp(tmpc->mpc_name, mpc->mpc_name) == 0) { 528 error = EEXIST; 529 goto out; 530 } 531 } 532 } 533 if (mpc->mpc_field_off != NULL) { 534 slot = ffs(mac_slot_offsets_free); 535 if (slot == 0) { 536 error = ENOMEM; 537 goto out; 538 } 539 slot--; 540 mac_slot_offsets_free &= ~(1 << slot); 541 *mpc->mpc_field_off = slot; 542 } 543 mpc->mpc_runtime_flags |= MPC_RUNTIME_FLAG_REGISTERED; 544 545 /* 546 * If we're loading a MAC module after the framework has initialized, 547 * it has to go into the dynamic list. If we're loading it before 548 * we've finished initializing, it can go into the static list with 549 * weaker locker requirements. 550 */ 551 if (static_entry) 552 LIST_INSERT_HEAD(&mac_static_policy_list, mpc, mpc_list); 553 else 554 LIST_INSERT_HEAD(&mac_policy_list, mpc, mpc_list); 555 556 /* 557 * Per-policy initialization. Currently, this takes place under the 558 * exclusive lock, so policies must not sleep in their init method. 559 * In the future, we may want to separate "init" from "start", with 560 * "init" occurring without the lock held. Likewise, on tear-down, 561 * breaking out "stop" from "destroy". 562 */ 563 if (mpc->mpc_ops->mpo_init != NULL) 564 (*(mpc->mpc_ops->mpo_init))(mpc); 565 566 mac_policy_fastpath_register(mpc); 567 568 mac_policy_update(); 569 570 SDT_PROBE1(mac, , policy, register, mpc); 571 printf("Security policy loaded: %s (%s)\n", mpc->mpc_fullname, 572 mpc->mpc_name); 573 574 out: 575 mac_policy_xunlock(); 576 return (error); 577 } 578 579 static int 580 mac_policy_unregister(struct mac_policy_conf *mpc) 581 { 582 583 /* 584 * If we fail the load, we may get a request to unload. Check to see 585 * if we did the run-time registration, and if not, silently succeed. 586 */ 587 mac_policy_xlock(); 588 if ((mpc->mpc_runtime_flags & MPC_RUNTIME_FLAG_REGISTERED) == 0) { 589 mac_policy_xunlock(); 590 return (0); 591 } 592 #if 0 593 /* 594 * Don't allow unloading modules with private data. 595 */ 596 if (mpc->mpc_field_off != NULL) { 597 mac_policy_xunlock(); 598 return (EBUSY); 599 } 600 #endif 601 /* 602 * Only allow the unload to proceed if the module is unloadable by 603 * its own definition. 604 */ 605 if ((mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_UNLOADOK) == 0) { 606 mac_policy_xunlock(); 607 return (EBUSY); 608 } 609 610 mac_policy_fastpath_unregister(mpc); 611 612 if (mpc->mpc_ops->mpo_destroy != NULL) 613 (*(mpc->mpc_ops->mpo_destroy))(mpc); 614 615 LIST_REMOVE(mpc, mpc_list); 616 mpc->mpc_runtime_flags &= ~MPC_RUNTIME_FLAG_REGISTERED; 617 mac_policy_update(); 618 mac_policy_xunlock(); 619 620 SDT_PROBE1(mac, , policy, unregister, mpc); 621 printf("Security policy unload: %s (%s)\n", mpc->mpc_fullname, 622 mpc->mpc_name); 623 624 return (0); 625 } 626 627 /* 628 * Allow MAC policy modules to register during boot, etc. 629 */ 630 int 631 mac_policy_modevent(module_t mod, int type, void *data) 632 { 633 struct mac_policy_conf *mpc; 634 int error; 635 636 error = 0; 637 mpc = (struct mac_policy_conf *) data; 638 639 #ifdef MAC_STATIC 640 if (mac_late) { 641 printf("mac_policy_modevent: MAC_STATIC and late\n"); 642 return (EBUSY); 643 } 644 #endif 645 646 SDT_PROBE2(mac, , policy, modevent, type, mpc); 647 switch (type) { 648 case MOD_LOAD: 649 if (mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_NOTLATE && 650 mac_late) { 651 printf("mac_policy_modevent: can't load %s policy " 652 "after booting\n", mpc->mpc_name); 653 error = EBUSY; 654 break; 655 } 656 error = mac_policy_register(mpc); 657 break; 658 case MOD_UNLOAD: 659 /* Don't unregister the module if it was never registered. */ 660 if ((mpc->mpc_runtime_flags & MPC_RUNTIME_FLAG_REGISTERED) 661 != 0) 662 error = mac_policy_unregister(mpc); 663 else 664 error = 0; 665 break; 666 default: 667 error = EOPNOTSUPP; 668 break; 669 } 670 671 return (error); 672 } 673 674 /* 675 * Define an error value precedence, and given two arguments, selects the 676 * value with the higher precedence. 677 */ 678 int 679 mac_error_select(int error1, int error2) 680 { 681 682 /* Certain decision-making errors take top priority. */ 683 if (error1 == EDEADLK || error2 == EDEADLK) 684 return (EDEADLK); 685 686 /* Invalid arguments should be reported where possible. */ 687 if (error1 == EINVAL || error2 == EINVAL) 688 return (EINVAL); 689 690 /* Precedence goes to "visibility", with both process and file. */ 691 if (error1 == ESRCH || error2 == ESRCH) 692 return (ESRCH); 693 694 if (error1 == ENOENT || error2 == ENOENT) 695 return (ENOENT); 696 697 /* Precedence goes to DAC/MAC protections. */ 698 if (error1 == EACCES || error2 == EACCES) 699 return (EACCES); 700 701 /* Precedence goes to privilege. */ 702 if (error1 == EPERM || error2 == EPERM) 703 return (EPERM); 704 705 /* Precedence goes to error over success; otherwise, arbitrary. */ 706 if (error1 != 0) 707 return (error1); 708 return (error2); 709 } 710 711 int 712 mac_check_structmac_consistent(struct mac *mac) 713 { 714 715 /* Require that labels have a non-zero length. */ 716 if (mac->m_buflen > MAC_MAX_LABEL_BUF_LEN || 717 mac->m_buflen <= sizeof("")) 718 return (EINVAL); 719 720 return (0); 721 } 722 723 SYSINIT(mac, SI_SUB_MAC, SI_ORDER_FIRST, mac_init, NULL); 724 SYSINIT(mac_late, SI_SUB_MAC_LATE, SI_ORDER_FIRST, mac_late_init, NULL); 725