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 #include <sys/vnode.h> 86 87 #include <security/mac/mac_framework.h> 88 #include <security/mac/mac_internal.h> 89 #include <security/mac/mac_policy.h> 90 91 /* 92 * DTrace SDT providers for MAC. 93 */ 94 SDT_PROVIDER_DEFINE(mac); 95 SDT_PROVIDER_DEFINE(mac_framework); 96 97 SDT_PROBE_DEFINE2(mac, , policy, modevent, "int", 98 "struct mac_policy_conf *"); 99 SDT_PROBE_DEFINE1(mac, , policy, register, 100 "struct mac_policy_conf *"); 101 SDT_PROBE_DEFINE1(mac, , policy, unregister, 102 "struct mac_policy_conf *"); 103 104 /* 105 * Root sysctl node for all MAC and MAC policy controls. 106 */ 107 SYSCTL_NODE(_security, OID_AUTO, mac, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 108 "TrustedBSD MAC policy controls"); 109 110 /* 111 * Declare that the kernel provides MAC support, version 3 (FreeBSD 7.x). 112 * This permits modules to refuse to be loaded if the necessary support isn't 113 * present, even if it's pre-boot. 114 */ 115 MODULE_VERSION(kernel_mac_support, MAC_VERSION); 116 117 static unsigned int mac_version = MAC_VERSION; 118 SYSCTL_UINT(_security_mac, OID_AUTO, version, CTLFLAG_RD, &mac_version, 0, 119 ""); 120 121 /* 122 * Flags for inlined checks. Note this would be best hotpatched at runtime. 123 * The following is a band-aid. 124 * 125 * Use FPFLAG for hooks running in commonly executed paths and FPFLAG_RARE 126 * for the rest. 127 */ 128 #define FPFLAG(f) \ 129 bool __read_frequently mac_##f##_fp_flag 130 131 #define FPFLAG_RARE(f) \ 132 bool __read_mostly mac_##f##_fp_flag 133 134 FPFLAG(priv_check); 135 FPFLAG(priv_grant); 136 FPFLAG(vnode_check_lookup); 137 FPFLAG(vnode_check_open); 138 FPFLAG(vnode_check_stat); 139 FPFLAG(vnode_check_read); 140 FPFLAG(vnode_check_write); 141 FPFLAG(vnode_check_mmap); 142 FPFLAG_RARE(vnode_check_poll); 143 FPFLAG_RARE(vnode_check_rename_from); 144 FPFLAG_RARE(vnode_check_access); 145 FPFLAG_RARE(vnode_check_readlink); 146 FPFLAG_RARE(pipe_check_stat); 147 FPFLAG_RARE(pipe_check_poll); 148 FPFLAG_RARE(pipe_check_read); 149 FPFLAG_RARE(ifnet_create_mbuf); 150 FPFLAG_RARE(ifnet_check_transmit); 151 152 #undef FPFLAG 153 #undef FPFLAG_RARE 154 155 /* 156 * Labels consist of a indexed set of "slots", which are allocated policies 157 * as required. The MAC Framework maintains a bitmask of slots allocated so 158 * far to prevent reuse. Slots cannot be reused, as the MAC Framework 159 * guarantees that newly allocated slots in labels will be NULL unless 160 * otherwise initialized, and because we do not have a mechanism to garbage 161 * collect slots on policy unload. As labeled policies tend to be statically 162 * loaded during boot, and not frequently unloaded and reloaded, this is not 163 * generally an issue. 164 */ 165 #if MAC_MAX_SLOTS > 32 166 #error "MAC_MAX_SLOTS too large" 167 #endif 168 169 static unsigned int mac_max_slots = MAC_MAX_SLOTS; 170 static unsigned int mac_slot_offsets_free = (1 << MAC_MAX_SLOTS) - 1; 171 SYSCTL_UINT(_security_mac, OID_AUTO, max_slots, CTLFLAG_RD, &mac_max_slots, 172 0, ""); 173 174 /* 175 * Has the kernel started generating labeled objects yet? All read/write 176 * access to this variable is serialized during the boot process. Following 177 * the end of serialization, we don't update this flag; no locking. 178 */ 179 static int mac_late = 0; 180 181 /* 182 * Each policy declares a mask of object types requiring labels to be 183 * allocated for them. For convenience, we combine and cache the bitwise or 184 * of the per-policy object flags to track whether we will allocate a label 185 * for an object type at run-time. 186 */ 187 uint64_t mac_labeled; 188 SYSCTL_UQUAD(_security_mac, OID_AUTO, labeled, CTLFLAG_RD, &mac_labeled, 0, 189 "Mask of object types being labeled"); 190 191 MALLOC_DEFINE(M_MACTEMP, "mactemp", "MAC temporary label storage"); 192 193 /* 194 * MAC policy modules are placed in one of two lists: mac_static_policy_list, 195 * for policies that are loaded early and cannot be unloaded, and 196 * mac_policy_list, which holds policies either loaded later in the boot 197 * cycle or that may be unloaded. The static policy list does not require 198 * locks to iterate over, but the dynamic list requires synchronization. 199 * Support for dynamic policy loading can be compiled out using the 200 * MAC_STATIC kernel option. 201 * 202 * The dynamic policy list is protected by two locks: modifying the list 203 * requires both locks to be held exclusively. One of the locks, 204 * mac_policy_rm, is acquired over policy entry points that will never sleep; 205 * the other, mac_policy_rms, is acquired over policy entry points that may 206 * sleep. The former category will be used when kernel locks may be held 207 * over calls to the MAC Framework, during network processing in ithreads, 208 * etc. The latter will tend to involve potentially blocking memory 209 * allocations, extended attribute I/O, etc. 210 */ 211 #ifndef MAC_STATIC 212 static struct rmlock mac_policy_rm; /* Non-sleeping entry points. */ 213 static struct rmslock mac_policy_rms; /* Sleeping entry points. */ 214 #endif 215 216 struct mac_policy_list_head mac_policy_list; 217 struct mac_policy_list_head mac_static_policy_list; 218 u_int mac_policy_count; /* Registered policy count. */ 219 220 static void mac_policy_xlock(void); 221 static void mac_policy_xlock_assert(void); 222 static void mac_policy_xunlock(void); 223 224 void 225 mac_policy_slock_nosleep(struct rm_priotracker *tracker) 226 { 227 228 #ifndef MAC_STATIC 229 if (!mac_late) 230 return; 231 232 rm_rlock(&mac_policy_rm, tracker); 233 #endif 234 } 235 236 void 237 mac_policy_slock_sleep(void) 238 { 239 240 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 241 "mac_policy_slock_sleep"); 242 243 #ifndef MAC_STATIC 244 if (!mac_late) 245 return; 246 247 rms_rlock(&mac_policy_rms); 248 #endif 249 } 250 251 void 252 mac_policy_sunlock_nosleep(struct rm_priotracker *tracker) 253 { 254 255 #ifndef MAC_STATIC 256 if (!mac_late) 257 return; 258 259 rm_runlock(&mac_policy_rm, tracker); 260 #endif 261 } 262 263 void 264 mac_policy_sunlock_sleep(void) 265 { 266 267 #ifndef MAC_STATIC 268 if (!mac_late) 269 return; 270 271 rms_runlock(&mac_policy_rms); 272 #endif 273 } 274 275 static void 276 mac_policy_xlock(void) 277 { 278 279 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 280 "mac_policy_xlock()"); 281 282 #ifndef MAC_STATIC 283 if (!mac_late) 284 return; 285 286 rms_wlock(&mac_policy_rms); 287 rm_wlock(&mac_policy_rm); 288 #endif 289 } 290 291 static void 292 mac_policy_xunlock(void) 293 { 294 295 #ifndef MAC_STATIC 296 if (!mac_late) 297 return; 298 299 rm_wunlock(&mac_policy_rm); 300 rms_wunlock(&mac_policy_rms); 301 #endif 302 } 303 304 static void 305 mac_policy_xlock_assert(void) 306 { 307 308 #ifndef MAC_STATIC 309 if (!mac_late) 310 return; 311 312 rm_assert(&mac_policy_rm, RA_WLOCKED); 313 #endif 314 } 315 316 /* 317 * Initialize the MAC subsystem, including appropriate SMP locks. 318 */ 319 static void 320 mac_init(void) 321 { 322 323 LIST_INIT(&mac_static_policy_list); 324 LIST_INIT(&mac_policy_list); 325 mac_labelzone_init(); 326 327 #ifndef MAC_STATIC 328 rm_init_flags(&mac_policy_rm, "mac_policy_rm", RM_NOWITNESS | 329 RM_RECURSE); 330 rms_init(&mac_policy_rms, "mac_policy_rms"); 331 #endif 332 } 333 334 /* 335 * For the purposes of modules that want to know if they were loaded "early", 336 * set the mac_late flag once we've processed modules either linked into the 337 * kernel, or loaded before the kernel startup. 338 */ 339 static void 340 mac_late_init(void) 341 { 342 343 mac_late = 1; 344 } 345 346 /* 347 * Given a policy, derive from its set of non-NULL label init methods what 348 * object types the policy is interested in. 349 */ 350 static uint64_t 351 mac_policy_getlabeled(struct mac_policy_conf *mpc) 352 { 353 uint64_t labeled; 354 355 #define MPC_FLAG(method, flag) \ 356 if (mpc->mpc_ops->mpo_ ## method != NULL) \ 357 labeled |= (flag); \ 358 359 labeled = 0; 360 MPC_FLAG(cred_init_label, MPC_OBJECT_CRED); 361 MPC_FLAG(proc_init_label, MPC_OBJECT_PROC); 362 MPC_FLAG(vnode_init_label, MPC_OBJECT_VNODE); 363 MPC_FLAG(inpcb_init_label, MPC_OBJECT_INPCB); 364 MPC_FLAG(socket_init_label, MPC_OBJECT_SOCKET); 365 MPC_FLAG(devfs_init_label, MPC_OBJECT_DEVFS); 366 MPC_FLAG(mbuf_init_label, MPC_OBJECT_MBUF); 367 MPC_FLAG(ipq_init_label, MPC_OBJECT_IPQ); 368 MPC_FLAG(ifnet_init_label, MPC_OBJECT_IFNET); 369 MPC_FLAG(bpfdesc_init_label, MPC_OBJECT_BPFDESC); 370 MPC_FLAG(pipe_init_label, MPC_OBJECT_PIPE); 371 MPC_FLAG(mount_init_label, MPC_OBJECT_MOUNT); 372 MPC_FLAG(posixsem_init_label, MPC_OBJECT_POSIXSEM); 373 MPC_FLAG(posixshm_init_label, MPC_OBJECT_POSIXSHM); 374 MPC_FLAG(sysvmsg_init_label, MPC_OBJECT_SYSVMSG); 375 MPC_FLAG(sysvmsq_init_label, MPC_OBJECT_SYSVMSQ); 376 MPC_FLAG(sysvsem_init_label, MPC_OBJECT_SYSVSEM); 377 MPC_FLAG(sysvshm_init_label, MPC_OBJECT_SYSVSHM); 378 MPC_FLAG(syncache_init_label, MPC_OBJECT_SYNCACHE); 379 MPC_FLAG(ip6q_init_label, MPC_OBJECT_IP6Q); 380 381 #undef MPC_FLAG 382 return (labeled); 383 } 384 385 /* 386 * When policies are loaded or unloaded, walk the list of registered policies 387 * and built mac_labeled, a bitmask representing the union of all objects 388 * requiring labels across all policies. 389 */ 390 static void 391 mac_policy_update(void) 392 { 393 struct mac_policy_conf *mpc; 394 395 mac_policy_xlock_assert(); 396 397 mac_labeled = 0; 398 mac_policy_count = 0; 399 LIST_FOREACH(mpc, &mac_static_policy_list, mpc_list) { 400 mac_labeled |= mac_policy_getlabeled(mpc); 401 mac_policy_count++; 402 } 403 LIST_FOREACH(mpc, &mac_policy_list, mpc_list) { 404 mac_labeled |= mac_policy_getlabeled(mpc); 405 mac_policy_count++; 406 } 407 408 cache_fast_lookup_enabled_recalc(); 409 } 410 411 /* 412 * There are frequently used code paths which check for rarely installed 413 * policies. Gross hack below enables doing it in a cheap manner. 414 */ 415 416 #define FPO(f) (offsetof(struct mac_policy_ops, mpo_##f) / sizeof(uintptr_t)) 417 418 struct mac_policy_fastpath_elem { 419 int count; 420 bool *flag; 421 size_t offset; 422 }; 423 424 struct mac_policy_fastpath_elem mac_policy_fastpath_array[] = { 425 { .offset = FPO(priv_check), .flag = &mac_priv_check_fp_flag }, 426 { .offset = FPO(priv_grant), .flag = &mac_priv_grant_fp_flag }, 427 { .offset = FPO(vnode_check_lookup), 428 .flag = &mac_vnode_check_lookup_fp_flag }, 429 { .offset = FPO(vnode_check_readlink), 430 .flag = &mac_vnode_check_readlink_fp_flag }, 431 { .offset = FPO(vnode_check_open), 432 .flag = &mac_vnode_check_open_fp_flag }, 433 { .offset = FPO(vnode_check_stat), 434 .flag = &mac_vnode_check_stat_fp_flag }, 435 { .offset = FPO(vnode_check_read), 436 .flag = &mac_vnode_check_read_fp_flag }, 437 { .offset = FPO(vnode_check_write), 438 .flag = &mac_vnode_check_write_fp_flag }, 439 { .offset = FPO(vnode_check_mmap), 440 .flag = &mac_vnode_check_mmap_fp_flag }, 441 { .offset = FPO(vnode_check_poll), 442 .flag = &mac_vnode_check_poll_fp_flag }, 443 { .offset = FPO(vnode_check_rename_from), 444 .flag = &mac_vnode_check_rename_from_fp_flag }, 445 { .offset = FPO(vnode_check_access), 446 .flag = &mac_vnode_check_access_fp_flag }, 447 { .offset = FPO(pipe_check_stat), 448 .flag = &mac_pipe_check_stat_fp_flag }, 449 { .offset = FPO(pipe_check_poll), 450 .flag = &mac_pipe_check_poll_fp_flag }, 451 { .offset = FPO(pipe_check_read), 452 .flag = &mac_pipe_check_read_fp_flag }, 453 { .offset = FPO(ifnet_create_mbuf), 454 .flag = &mac_ifnet_create_mbuf_fp_flag }, 455 { .offset = FPO(ifnet_check_transmit), 456 .flag = &mac_ifnet_check_transmit_fp_flag }, 457 }; 458 459 static void 460 mac_policy_fastpath_enable(struct mac_policy_fastpath_elem *mpfe) 461 { 462 463 MPASS(mpfe->count >= 0); 464 mpfe->count++; 465 if (mpfe->count == 1) { 466 MPASS(*mpfe->flag == false); 467 *mpfe->flag = true; 468 } 469 } 470 471 static void 472 mac_policy_fastpath_disable(struct mac_policy_fastpath_elem *mpfe) 473 { 474 475 MPASS(mpfe->count >= 1); 476 mpfe->count--; 477 if (mpfe->count == 0) { 478 MPASS(*mpfe->flag == true); 479 *mpfe->flag = false; 480 } 481 } 482 483 static void 484 mac_policy_fastpath_register(struct mac_policy_conf *mpc) 485 { 486 struct mac_policy_fastpath_elem *mpfe; 487 uintptr_t **ops; 488 int i; 489 490 mac_policy_xlock_assert(); 491 492 ops = (uintptr_t **)mpc->mpc_ops; 493 for (i = 0; i < nitems(mac_policy_fastpath_array); i++) { 494 mpfe = &mac_policy_fastpath_array[i]; 495 if (ops[mpfe->offset] != NULL) 496 mac_policy_fastpath_enable(mpfe); 497 } 498 } 499 500 static void 501 mac_policy_fastpath_unregister(struct mac_policy_conf *mpc) 502 { 503 struct mac_policy_fastpath_elem *mpfe; 504 uintptr_t **ops; 505 int i; 506 507 mac_policy_xlock_assert(); 508 509 ops = (uintptr_t **)mpc->mpc_ops; 510 for (i = 0; i < nitems(mac_policy_fastpath_array); i++) { 511 mpfe = &mac_policy_fastpath_array[i]; 512 if (ops[mpfe->offset] != NULL) 513 mac_policy_fastpath_disable(mpfe); 514 } 515 } 516 517 #undef FPO 518 519 static int 520 mac_policy_register(struct mac_policy_conf *mpc) 521 { 522 struct mac_policy_conf *tmpc; 523 int error, slot, static_entry; 524 525 error = 0; 526 527 /* 528 * We don't technically need exclusive access while !mac_late, but 529 * hold it for assertion consistency. 530 */ 531 mac_policy_xlock(); 532 533 /* 534 * If the module can potentially be unloaded, or we're loading late, 535 * we have to stick it in the non-static list and pay an extra 536 * performance overhead. Otherwise, we can pay a light locking cost 537 * and stick it in the static list. 538 */ 539 static_entry = (!mac_late && 540 !(mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_UNLOADOK)); 541 542 if (static_entry) { 543 LIST_FOREACH(tmpc, &mac_static_policy_list, mpc_list) { 544 if (strcmp(tmpc->mpc_name, mpc->mpc_name) == 0) { 545 error = EEXIST; 546 goto out; 547 } 548 } 549 } else { 550 LIST_FOREACH(tmpc, &mac_policy_list, mpc_list) { 551 if (strcmp(tmpc->mpc_name, mpc->mpc_name) == 0) { 552 error = EEXIST; 553 goto out; 554 } 555 } 556 } 557 if (mpc->mpc_field_off != NULL) { 558 slot = ffs(mac_slot_offsets_free); 559 if (slot == 0) { 560 error = ENOMEM; 561 goto out; 562 } 563 slot--; 564 mac_slot_offsets_free &= ~(1 << slot); 565 *mpc->mpc_field_off = slot; 566 } 567 mpc->mpc_runtime_flags |= MPC_RUNTIME_FLAG_REGISTERED; 568 569 /* 570 * If we're loading a MAC module after the framework has initialized, 571 * it has to go into the dynamic list. If we're loading it before 572 * we've finished initializing, it can go into the static list with 573 * weaker locker requirements. 574 */ 575 if (static_entry) 576 LIST_INSERT_HEAD(&mac_static_policy_list, mpc, mpc_list); 577 else 578 LIST_INSERT_HEAD(&mac_policy_list, mpc, mpc_list); 579 580 /* 581 * Per-policy initialization. Currently, this takes place under the 582 * exclusive lock, so policies must not sleep in their init method. 583 * In the future, we may want to separate "init" from "start", with 584 * "init" occurring without the lock held. Likewise, on tear-down, 585 * breaking out "stop" from "destroy". 586 */ 587 if (mpc->mpc_ops->mpo_init != NULL) 588 (*(mpc->mpc_ops->mpo_init))(mpc); 589 590 mac_policy_fastpath_register(mpc); 591 592 mac_policy_update(); 593 594 SDT_PROBE1(mac, , policy, register, mpc); 595 printf("Security policy loaded: %s (%s)\n", mpc->mpc_fullname, 596 mpc->mpc_name); 597 598 out: 599 mac_policy_xunlock(); 600 return (error); 601 } 602 603 static int 604 mac_policy_unregister(struct mac_policy_conf *mpc) 605 { 606 607 /* 608 * If we fail the load, we may get a request to unload. Check to see 609 * if we did the run-time registration, and if not, silently succeed. 610 */ 611 mac_policy_xlock(); 612 if ((mpc->mpc_runtime_flags & MPC_RUNTIME_FLAG_REGISTERED) == 0) { 613 mac_policy_xunlock(); 614 return (0); 615 } 616 #if 0 617 /* 618 * Don't allow unloading modules with private data. 619 */ 620 if (mpc->mpc_field_off != NULL) { 621 mac_policy_xunlock(); 622 return (EBUSY); 623 } 624 #endif 625 /* 626 * Only allow the unload to proceed if the module is unloadable by 627 * its own definition. 628 */ 629 if ((mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_UNLOADOK) == 0) { 630 mac_policy_xunlock(); 631 return (EBUSY); 632 } 633 634 mac_policy_fastpath_unregister(mpc); 635 636 if (mpc->mpc_ops->mpo_destroy != NULL) 637 (*(mpc->mpc_ops->mpo_destroy))(mpc); 638 639 LIST_REMOVE(mpc, mpc_list); 640 mpc->mpc_runtime_flags &= ~MPC_RUNTIME_FLAG_REGISTERED; 641 mac_policy_update(); 642 mac_policy_xunlock(); 643 644 SDT_PROBE1(mac, , policy, unregister, mpc); 645 printf("Security policy unload: %s (%s)\n", mpc->mpc_fullname, 646 mpc->mpc_name); 647 648 return (0); 649 } 650 651 /* 652 * Allow MAC policy modules to register during boot, etc. 653 */ 654 int 655 mac_policy_modevent(module_t mod, int type, void *data) 656 { 657 struct mac_policy_conf *mpc; 658 int error; 659 660 error = 0; 661 mpc = (struct mac_policy_conf *) data; 662 663 #ifdef MAC_STATIC 664 if (mac_late) { 665 printf("mac_policy_modevent: MAC_STATIC and late\n"); 666 return (EBUSY); 667 } 668 #endif 669 670 SDT_PROBE2(mac, , policy, modevent, type, mpc); 671 switch (type) { 672 case MOD_LOAD: 673 if (mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_NOTLATE && 674 mac_late) { 675 printf("mac_policy_modevent: can't load %s policy " 676 "after booting\n", mpc->mpc_name); 677 error = EBUSY; 678 break; 679 } 680 error = mac_policy_register(mpc); 681 break; 682 case MOD_UNLOAD: 683 /* Don't unregister the module if it was never registered. */ 684 if ((mpc->mpc_runtime_flags & MPC_RUNTIME_FLAG_REGISTERED) 685 != 0) 686 error = mac_policy_unregister(mpc); 687 else 688 error = 0; 689 break; 690 default: 691 error = EOPNOTSUPP; 692 break; 693 } 694 695 return (error); 696 } 697 698 /* 699 * Define an error value precedence, and given two arguments, selects the 700 * value with the higher precedence. 701 */ 702 int 703 mac_error_select(int error1, int error2) 704 { 705 706 /* Certain decision-making errors take top priority. */ 707 if (error1 == EDEADLK || error2 == EDEADLK) 708 return (EDEADLK); 709 710 /* Invalid arguments should be reported where possible. */ 711 if (error1 == EINVAL || error2 == EINVAL) 712 return (EINVAL); 713 714 /* Precedence goes to "visibility", with both process and file. */ 715 if (error1 == ESRCH || error2 == ESRCH) 716 return (ESRCH); 717 718 if (error1 == ENOENT || error2 == ENOENT) 719 return (ENOENT); 720 721 /* Precedence goes to DAC/MAC protections. */ 722 if (error1 == EACCES || error2 == EACCES) 723 return (EACCES); 724 725 /* Precedence goes to privilege. */ 726 if (error1 == EPERM || error2 == EPERM) 727 return (EPERM); 728 729 /* Precedence goes to error over success; otherwise, arbitrary. */ 730 if (error1 != 0) 731 return (error1); 732 return (error2); 733 } 734 735 int 736 mac_check_structmac_consistent(struct mac *mac) 737 { 738 739 /* Require that labels have a non-zero length. */ 740 if (mac->m_buflen > MAC_MAX_LABEL_BUF_LEN || 741 mac->m_buflen <= sizeof("")) 742 return (EINVAL); 743 744 return (0); 745 } 746 747 SYSINIT(mac, SI_SUB_MAC, SI_ORDER_FIRST, mac_init, NULL); 748 SYSINIT(mac_late, SI_SUB_MAC_LATE, SI_ORDER_FIRST, mac_late_init, NULL); 749