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 #include <sys/param.h>
73 #include <sys/systm.h>
74 #include <sys/condvar.h>
75 #include <sys/kernel.h>
76 #include <sys/lock.h>
77 #include <sys/mac.h>
78 #include <sys/module.h>
79 #include <sys/rmlock.h>
80 #include <sys/sdt.h>
81 #include <sys/sx.h>
82 #include <sys/sysctl.h>
83 #include <sys/vnode.h>
84
85 #include <security/mac/mac_framework.h>
86 #include <security/mac/mac_internal.h>
87 #include <security/mac/mac_policy.h>
88
89 /*
90 * DTrace SDT providers for MAC.
91 */
92 SDT_PROVIDER_DEFINE(mac);
93 SDT_PROVIDER_DEFINE(mac_framework);
94
95 SDT_PROBE_DEFINE2(mac, , policy, modevent, "int",
96 "struct mac_policy_conf *");
97 SDT_PROBE_DEFINE1(mac, , policy, register,
98 "struct mac_policy_conf *");
99 SDT_PROBE_DEFINE1(mac, , policy, unregister,
100 "struct mac_policy_conf *");
101
102 /*
103 * Root sysctl node for all MAC and MAC policy controls.
104 */
105 SYSCTL_NODE(_security, OID_AUTO, mac, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
106 "TrustedBSD MAC policy controls");
107
108 /*
109 * Declare that the kernel provides MAC support, version 3 (FreeBSD 7.x).
110 * This permits modules to refuse to be loaded if the necessary support isn't
111 * present, even if it's pre-boot.
112 */
113 MODULE_VERSION(kernel_mac_support, MAC_VERSION);
114
115 static unsigned int mac_version = MAC_VERSION;
116 SYSCTL_UINT(_security_mac, OID_AUTO, version, CTLFLAG_RD, &mac_version, 0,
117 "");
118
119 /*
120 * Flags for inlined checks. Note this would be best hotpatched at runtime.
121 * The following is a band-aid.
122 *
123 * Use FPFLAG for hooks running in commonly executed paths and FPFLAG_RARE
124 * for the rest.
125 */
126 #define FPFLAG(f) \
127 bool __read_frequently mac_##f##_fp_flag
128
129 #define FPFLAG_RARE(f) \
130 bool __read_mostly mac_##f##_fp_flag
131
132 FPFLAG(priv_check);
133 FPFLAG(priv_grant);
134 FPFLAG(vnode_check_lookup);
135 FPFLAG(vnode_check_open);
136 FPFLAG(vnode_check_stat);
137 FPFLAG(vnode_check_read);
138 FPFLAG(vnode_check_write);
139 FPFLAG(vnode_check_mmap);
140 FPFLAG_RARE(vnode_check_poll);
141 FPFLAG_RARE(vnode_check_rename_from);
142 FPFLAG_RARE(vnode_check_access);
143 FPFLAG_RARE(vnode_check_readlink);
144 FPFLAG_RARE(pipe_check_stat);
145 FPFLAG_RARE(pipe_check_poll);
146 FPFLAG_RARE(pipe_check_read);
147 FPFLAG_RARE(ifnet_create_mbuf);
148 FPFLAG_RARE(ifnet_check_transmit);
149
150 #undef FPFLAG
151 #undef FPFLAG_RARE
152
153 /*
154 * Labels consist of a indexed set of "slots", which are allocated policies
155 * as required. The MAC Framework maintains a bitmask of slots allocated so
156 * far to prevent reuse. Slots cannot be reused, as the MAC Framework
157 * guarantees that newly allocated slots in labels will be NULL unless
158 * otherwise initialized, and because we do not have a mechanism to garbage
159 * collect slots on policy unload. As labeled policies tend to be statically
160 * loaded during boot, and not frequently unloaded and reloaded, this is not
161 * generally an issue.
162 */
163 #if MAC_MAX_SLOTS > 32
164 #error "MAC_MAX_SLOTS too large"
165 #endif
166
167 static unsigned int mac_max_slots = MAC_MAX_SLOTS;
168 static unsigned int mac_slot_offsets_free = (1 << MAC_MAX_SLOTS) - 1;
169 SYSCTL_UINT(_security_mac, OID_AUTO, max_slots, CTLFLAG_RD, &mac_max_slots,
170 0, "");
171
172 /*
173 * Has the kernel started generating labeled objects yet? All read/write
174 * access to this variable is serialized during the boot process. Following
175 * the end of serialization, we don't update this flag; no locking.
176 */
177 static int mac_late = 0;
178
179 /*
180 * Each policy declares a mask of object types requiring labels to be
181 * allocated for them. For convenience, we combine and cache the bitwise or
182 * of the per-policy object flags to track whether we will allocate a label
183 * for an object type at run-time.
184 */
185 uint64_t mac_labeled;
186 SYSCTL_UQUAD(_security_mac, OID_AUTO, labeled, CTLFLAG_RD, &mac_labeled, 0,
187 "Mask of object types being labeled");
188
189 MALLOC_DEFINE(M_MACTEMP, "mactemp", "MAC temporary label storage");
190
191 /*
192 * MAC policy modules are placed in one of two lists: mac_static_policy_list,
193 * for policies that are loaded early and cannot be unloaded, and
194 * mac_policy_list, which holds policies either loaded later in the boot
195 * cycle or that may be unloaded. The static policy list does not require
196 * locks to iterate over, but the dynamic list requires synchronization.
197 * Support for dynamic policy loading can be compiled out using the
198 * MAC_STATIC kernel option.
199 *
200 * The dynamic policy list is protected by two locks: modifying the list
201 * requires both locks to be held exclusively. One of the locks,
202 * mac_policy_rm, is acquired over policy entry points that will never sleep;
203 * the other, mac_policy_rms, is acquired over policy entry points that may
204 * sleep. The former category will be used when kernel locks may be held
205 * over calls to the MAC Framework, during network processing in ithreads,
206 * etc. The latter will tend to involve potentially blocking memory
207 * allocations, extended attribute I/O, etc.
208 */
209 #ifndef MAC_STATIC
210 static struct rmlock mac_policy_rm; /* Non-sleeping entry points. */
211 static struct rmslock mac_policy_rms; /* Sleeping entry points. */
212 #endif
213
214 struct mac_policy_list_head mac_policy_list;
215 struct mac_policy_list_head mac_static_policy_list;
216 u_int mac_policy_count; /* Registered policy count. */
217
218 static void mac_policy_xlock(void);
219 static void mac_policy_xlock_assert(void);
220 static void mac_policy_xunlock(void);
221
222 void
mac_policy_slock_nosleep(struct rm_priotracker * tracker)223 mac_policy_slock_nosleep(struct rm_priotracker *tracker)
224 {
225
226 #ifndef MAC_STATIC
227 if (!mac_late)
228 return;
229
230 rm_rlock(&mac_policy_rm, tracker);
231 #endif
232 }
233
234 void
mac_policy_slock_sleep(void)235 mac_policy_slock_sleep(void)
236 {
237
238 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
239 "mac_policy_slock_sleep");
240
241 #ifndef MAC_STATIC
242 if (!mac_late)
243 return;
244
245 rms_rlock(&mac_policy_rms);
246 #endif
247 }
248
249 void
mac_policy_sunlock_nosleep(struct rm_priotracker * tracker)250 mac_policy_sunlock_nosleep(struct rm_priotracker *tracker)
251 {
252
253 #ifndef MAC_STATIC
254 if (!mac_late)
255 return;
256
257 rm_runlock(&mac_policy_rm, tracker);
258 #endif
259 }
260
261 void
mac_policy_sunlock_sleep(void)262 mac_policy_sunlock_sleep(void)
263 {
264
265 #ifndef MAC_STATIC
266 if (!mac_late)
267 return;
268
269 rms_runlock(&mac_policy_rms);
270 #endif
271 }
272
273 static void
mac_policy_xlock(void)274 mac_policy_xlock(void)
275 {
276
277 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
278 "mac_policy_xlock()");
279
280 #ifndef MAC_STATIC
281 if (!mac_late)
282 return;
283
284 rms_wlock(&mac_policy_rms);
285 rm_wlock(&mac_policy_rm);
286 #endif
287 }
288
289 static void
mac_policy_xunlock(void)290 mac_policy_xunlock(void)
291 {
292
293 #ifndef MAC_STATIC
294 if (!mac_late)
295 return;
296
297 rm_wunlock(&mac_policy_rm);
298 rms_wunlock(&mac_policy_rms);
299 #endif
300 }
301
302 static void
mac_policy_xlock_assert(void)303 mac_policy_xlock_assert(void)
304 {
305
306 #ifndef MAC_STATIC
307 if (!mac_late)
308 return;
309
310 rm_assert(&mac_policy_rm, RA_WLOCKED);
311 #endif
312 }
313
314 /*
315 * Initialize the MAC subsystem, including appropriate SMP locks.
316 */
317 static void
mac_init(void)318 mac_init(void)
319 {
320
321 LIST_INIT(&mac_static_policy_list);
322 LIST_INIT(&mac_policy_list);
323 mac_labelzone_init();
324
325 #ifndef MAC_STATIC
326 rm_init_flags(&mac_policy_rm, "mac_policy_rm", RM_NOWITNESS |
327 RM_RECURSE);
328 rms_init(&mac_policy_rms, "mac_policy_rms");
329 #endif
330 }
331
332 /*
333 * For the purposes of modules that want to know if they were loaded "early",
334 * set the mac_late flag once we've processed modules either linked into the
335 * kernel, or loaded before the kernel startup.
336 */
337 static void
mac_late_init(void)338 mac_late_init(void)
339 {
340
341 mac_late = 1;
342 }
343
344 /*
345 * Given a policy, derive from its set of non-NULL label init methods what
346 * object types the policy is interested in.
347 */
348 static uint64_t
mac_policy_getlabeled(struct mac_policy_conf * mpc)349 mac_policy_getlabeled(struct mac_policy_conf *mpc)
350 {
351 uint64_t labeled;
352
353 #define MPC_FLAG(method, flag) \
354 if (mpc->mpc_ops->mpo_ ## method != NULL) \
355 labeled |= (flag); \
356
357 labeled = 0;
358 MPC_FLAG(cred_init_label, MPC_OBJECT_CRED);
359 MPC_FLAG(proc_init_label, MPC_OBJECT_PROC);
360 MPC_FLAG(vnode_init_label, MPC_OBJECT_VNODE);
361 MPC_FLAG(inpcb_init_label, MPC_OBJECT_INPCB);
362 MPC_FLAG(socket_init_label, MPC_OBJECT_SOCKET);
363 MPC_FLAG(devfs_init_label, MPC_OBJECT_DEVFS);
364 MPC_FLAG(mbuf_init_label, MPC_OBJECT_MBUF);
365 MPC_FLAG(ipq_init_label, MPC_OBJECT_IPQ);
366 MPC_FLAG(ifnet_init_label, MPC_OBJECT_IFNET);
367 MPC_FLAG(bpfdesc_init_label, MPC_OBJECT_BPFDESC);
368 MPC_FLAG(pipe_init_label, MPC_OBJECT_PIPE);
369 MPC_FLAG(mount_init_label, MPC_OBJECT_MOUNT);
370 MPC_FLAG(posixsem_init_label, MPC_OBJECT_POSIXSEM);
371 MPC_FLAG(posixshm_init_label, MPC_OBJECT_POSIXSHM);
372 MPC_FLAG(sysvmsg_init_label, MPC_OBJECT_SYSVMSG);
373 MPC_FLAG(sysvmsq_init_label, MPC_OBJECT_SYSVMSQ);
374 MPC_FLAG(sysvsem_init_label, MPC_OBJECT_SYSVSEM);
375 MPC_FLAG(sysvshm_init_label, MPC_OBJECT_SYSVSHM);
376 MPC_FLAG(syncache_init_label, MPC_OBJECT_SYNCACHE);
377 MPC_FLAG(ip6q_init_label, MPC_OBJECT_IP6Q);
378
379 #undef MPC_FLAG
380 return (labeled);
381 }
382
383 /*
384 * When policies are loaded or unloaded, walk the list of registered policies
385 * and built mac_labeled, a bitmask representing the union of all objects
386 * requiring labels across all policies.
387 */
388 static void
mac_policy_update(void)389 mac_policy_update(void)
390 {
391 struct mac_policy_conf *mpc;
392
393 mac_policy_xlock_assert();
394
395 mac_labeled = 0;
396 mac_policy_count = 0;
397 LIST_FOREACH(mpc, &mac_static_policy_list, mpc_list) {
398 mac_labeled |= mac_policy_getlabeled(mpc);
399 mac_policy_count++;
400 }
401 LIST_FOREACH(mpc, &mac_policy_list, mpc_list) {
402 mac_labeled |= mac_policy_getlabeled(mpc);
403 mac_policy_count++;
404 }
405
406 cache_fast_lookup_enabled_recalc();
407 }
408
409 /*
410 * There are frequently used code paths which check for rarely installed
411 * policies. Gross hack below enables doing it in a cheap manner.
412 */
413
414 #define FPO(f) (offsetof(struct mac_policy_ops, mpo_##f) / sizeof(uintptr_t))
415
416 struct mac_policy_fastpath_elem {
417 int count;
418 bool *flag;
419 size_t offset;
420 };
421
422 struct mac_policy_fastpath_elem mac_policy_fastpath_array[] = {
423 { .offset = FPO(priv_check), .flag = &mac_priv_check_fp_flag },
424 { .offset = FPO(priv_grant), .flag = &mac_priv_grant_fp_flag },
425 { .offset = FPO(vnode_check_lookup),
426 .flag = &mac_vnode_check_lookup_fp_flag },
427 { .offset = FPO(vnode_check_readlink),
428 .flag = &mac_vnode_check_readlink_fp_flag },
429 { .offset = FPO(vnode_check_open),
430 .flag = &mac_vnode_check_open_fp_flag },
431 { .offset = FPO(vnode_check_stat),
432 .flag = &mac_vnode_check_stat_fp_flag },
433 { .offset = FPO(vnode_check_read),
434 .flag = &mac_vnode_check_read_fp_flag },
435 { .offset = FPO(vnode_check_write),
436 .flag = &mac_vnode_check_write_fp_flag },
437 { .offset = FPO(vnode_check_mmap),
438 .flag = &mac_vnode_check_mmap_fp_flag },
439 { .offset = FPO(vnode_check_poll),
440 .flag = &mac_vnode_check_poll_fp_flag },
441 { .offset = FPO(vnode_check_rename_from),
442 .flag = &mac_vnode_check_rename_from_fp_flag },
443 { .offset = FPO(vnode_check_access),
444 .flag = &mac_vnode_check_access_fp_flag },
445 { .offset = FPO(pipe_check_stat),
446 .flag = &mac_pipe_check_stat_fp_flag },
447 { .offset = FPO(pipe_check_poll),
448 .flag = &mac_pipe_check_poll_fp_flag },
449 { .offset = FPO(pipe_check_read),
450 .flag = &mac_pipe_check_read_fp_flag },
451 { .offset = FPO(ifnet_create_mbuf),
452 .flag = &mac_ifnet_create_mbuf_fp_flag },
453 { .offset = FPO(ifnet_check_transmit),
454 .flag = &mac_ifnet_check_transmit_fp_flag },
455 };
456
457 static void
mac_policy_fastpath_enable(struct mac_policy_fastpath_elem * mpfe)458 mac_policy_fastpath_enable(struct mac_policy_fastpath_elem *mpfe)
459 {
460
461 MPASS(mpfe->count >= 0);
462 mpfe->count++;
463 if (mpfe->count == 1) {
464 MPASS(*mpfe->flag == false);
465 *mpfe->flag = true;
466 }
467 }
468
469 static void
mac_policy_fastpath_disable(struct mac_policy_fastpath_elem * mpfe)470 mac_policy_fastpath_disable(struct mac_policy_fastpath_elem *mpfe)
471 {
472
473 MPASS(mpfe->count >= 1);
474 mpfe->count--;
475 if (mpfe->count == 0) {
476 MPASS(*mpfe->flag == true);
477 *mpfe->flag = false;
478 }
479 }
480
481 static void
mac_policy_fastpath_register(struct mac_policy_conf * mpc)482 mac_policy_fastpath_register(struct mac_policy_conf *mpc)
483 {
484 struct mac_policy_fastpath_elem *mpfe;
485 uintptr_t **ops;
486 int i;
487
488 mac_policy_xlock_assert();
489
490 ops = (uintptr_t **)mpc->mpc_ops;
491 for (i = 0; i < nitems(mac_policy_fastpath_array); i++) {
492 mpfe = &mac_policy_fastpath_array[i];
493 if (ops[mpfe->offset] != NULL)
494 mac_policy_fastpath_enable(mpfe);
495 }
496 }
497
498 static void
mac_policy_fastpath_unregister(struct mac_policy_conf * mpc)499 mac_policy_fastpath_unregister(struct mac_policy_conf *mpc)
500 {
501 struct mac_policy_fastpath_elem *mpfe;
502 uintptr_t **ops;
503 int i;
504
505 mac_policy_xlock_assert();
506
507 ops = (uintptr_t **)mpc->mpc_ops;
508 for (i = 0; i < nitems(mac_policy_fastpath_array); i++) {
509 mpfe = &mac_policy_fastpath_array[i];
510 if (ops[mpfe->offset] != NULL)
511 mac_policy_fastpath_disable(mpfe);
512 }
513 }
514
515 #undef FPO
516
517 static int
mac_policy_register(struct mac_policy_conf * mpc)518 mac_policy_register(struct mac_policy_conf *mpc)
519 {
520 struct mac_policy_list_head *mpc_list;
521 struct mac_policy_conf *last_mpc, *tmpc;
522 int error, slot, static_entry;
523
524 error = 0;
525
526 /*
527 * We don't technically need exclusive access while !mac_late, but
528 * hold it for assertion consistency.
529 */
530 mac_policy_xlock();
531
532 /*
533 * If the module can potentially be unloaded, or we're loading late,
534 * we have to stick it in the non-static list and pay an extra
535 * performance overhead. Otherwise, we can pay a light locking cost
536 * and stick it in the static list.
537 */
538 static_entry = (!mac_late &&
539 !(mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_UNLOADOK));
540
541 mpc_list = (static_entry) ? &mac_static_policy_list :
542 &mac_policy_list;
543 last_mpc = NULL;
544 LIST_FOREACH(tmpc, mpc_list, mpc_list) {
545 last_mpc = tmpc;
546 if (strcmp(tmpc->mpc_name, mpc->mpc_name) == 0) {
547 error = EEXIST;
548 goto out;
549 }
550 }
551 if (mpc->mpc_field_off != NULL) {
552 slot = ffs(mac_slot_offsets_free);
553 if (slot == 0) {
554 error = ENOMEM;
555 goto out;
556 }
557 slot--;
558 mac_slot_offsets_free &= ~(1 << slot);
559 *mpc->mpc_field_off = slot;
560 }
561 mpc->mpc_runtime_flags |= MPC_RUNTIME_FLAG_REGISTERED;
562
563 /*
564 * Some modules may depend on the operations of its dependencies.
565 * Inserting modules in order of registration ensures operations
566 * that work on the module list retain dependency order.
567 */
568 if (last_mpc == NULL)
569 LIST_INSERT_HEAD(mpc_list, mpc, mpc_list);
570 else
571 LIST_INSERT_AFTER(last_mpc, mpc, mpc_list);
572 /*
573 * Per-policy initialization. Currently, this takes place under the
574 * exclusive lock, so policies must not sleep in their init method.
575 * In the future, we may want to separate "init" from "start", with
576 * "init" occurring without the lock held. Likewise, on tear-down,
577 * breaking out "stop" from "destroy".
578 */
579 if (mpc->mpc_ops->mpo_init != NULL)
580 (*(mpc->mpc_ops->mpo_init))(mpc);
581
582 mac_policy_fastpath_register(mpc);
583
584 mac_policy_update();
585
586 SDT_PROBE1(mac, , policy, register, mpc);
587 printf("Security policy loaded: %s (%s)\n", mpc->mpc_fullname,
588 mpc->mpc_name);
589
590 out:
591 mac_policy_xunlock();
592 return (error);
593 }
594
595 static int
mac_policy_unregister(struct mac_policy_conf * mpc)596 mac_policy_unregister(struct mac_policy_conf *mpc)
597 {
598
599 /*
600 * If we fail the load, we may get a request to unload. Check to see
601 * if we did the run-time registration, and if not, silently succeed.
602 */
603 mac_policy_xlock();
604 if ((mpc->mpc_runtime_flags & MPC_RUNTIME_FLAG_REGISTERED) == 0) {
605 mac_policy_xunlock();
606 return (0);
607 }
608 #if 0
609 /*
610 * Don't allow unloading modules with private data.
611 */
612 if (mpc->mpc_field_off != NULL) {
613 mac_policy_xunlock();
614 return (EBUSY);
615 }
616 #endif
617 /*
618 * Only allow the unload to proceed if the module is unloadable by
619 * its own definition.
620 */
621 if ((mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_UNLOADOK) == 0) {
622 mac_policy_xunlock();
623 return (EBUSY);
624 }
625
626 mac_policy_fastpath_unregister(mpc);
627
628 if (mpc->mpc_ops->mpo_destroy != NULL)
629 (*(mpc->mpc_ops->mpo_destroy))(mpc);
630
631 LIST_REMOVE(mpc, mpc_list);
632 mpc->mpc_runtime_flags &= ~MPC_RUNTIME_FLAG_REGISTERED;
633 mac_policy_update();
634 mac_policy_xunlock();
635
636 SDT_PROBE1(mac, , policy, unregister, mpc);
637 printf("Security policy unload: %s (%s)\n", mpc->mpc_fullname,
638 mpc->mpc_name);
639
640 return (0);
641 }
642
643 /*
644 * Allow MAC policy modules to register during boot, etc.
645 */
646 int
mac_policy_modevent(module_t mod,int type,void * data)647 mac_policy_modevent(module_t mod, int type, void *data)
648 {
649 struct mac_policy_conf *mpc;
650 int error;
651
652 error = 0;
653 mpc = (struct mac_policy_conf *) data;
654
655 #ifdef MAC_STATIC
656 if (mac_late) {
657 printf("mac_policy_modevent: MAC_STATIC and late\n");
658 return (EBUSY);
659 }
660 #endif
661
662 SDT_PROBE2(mac, , policy, modevent, type, mpc);
663 switch (type) {
664 case MOD_LOAD:
665 if (mpc->mpc_loadtime_flags & MPC_LOADTIME_FLAG_NOTLATE &&
666 mac_late) {
667 printf("mac_policy_modevent: can't load %s policy "
668 "after booting\n", mpc->mpc_name);
669 error = EBUSY;
670 break;
671 }
672 error = mac_policy_register(mpc);
673 break;
674 case MOD_UNLOAD:
675 /* Don't unregister the module if it was never registered. */
676 if ((mpc->mpc_runtime_flags & MPC_RUNTIME_FLAG_REGISTERED)
677 != 0)
678 error = mac_policy_unregister(mpc);
679 else
680 error = 0;
681 break;
682 default:
683 error = EOPNOTSUPP;
684 break;
685 }
686
687 return (error);
688 }
689
690 /*
691 * Define an error value precedence, and given two arguments, selects the
692 * value with the higher precedence.
693 */
694 int
mac_error_select(int error1,int error2)695 mac_error_select(int error1, int error2)
696 {
697
698 /* Certain decision-making errors take top priority. */
699 if (error1 == EDEADLK || error2 == EDEADLK)
700 return (EDEADLK);
701
702 /* Invalid arguments should be reported where possible. */
703 if (error1 == EINVAL || error2 == EINVAL)
704 return (EINVAL);
705
706 /* Precedence goes to "visibility", with both process and file. */
707 if (error1 == ESRCH || error2 == ESRCH)
708 return (ESRCH);
709
710 if (error1 == ENOENT || error2 == ENOENT)
711 return (ENOENT);
712
713 /* Precedence goes to DAC/MAC protections. */
714 if (error1 == EACCES || error2 == EACCES)
715 return (EACCES);
716
717 /* Precedence goes to privilege. */
718 if (error1 == EPERM || error2 == EPERM)
719 return (EPERM);
720
721 /* Precedence goes to error over success; otherwise, arbitrary. */
722 if (error1 != 0)
723 return (error1);
724 return (error2);
725 }
726
727 int
mac_check_structmac_consistent(struct mac * mac)728 mac_check_structmac_consistent(struct mac *mac)
729 {
730
731 /* Require that labels have a non-zero length. */
732 if (mac->m_buflen > MAC_MAX_LABEL_BUF_LEN ||
733 mac->m_buflen <= sizeof(""))
734 return (EINVAL);
735
736 return (0);
737 }
738
739 SYSINIT(mac, SI_SUB_MAC, SI_ORDER_FIRST, mac_init, NULL);
740 SYSINIT(mac_late, SI_SUB_MAC_LATE, SI_ORDER_FIRST, mac_late_init, NULL);
741