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b0d623f7 1/*-
f427ee49 2 * Copyright (c) 1999-2020 Apple Inc.
b0d623f7
A
3 * Copyright (c) 2006-2007 Robert N. M. Watson
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of Apple Inc. ("Apple") nor the names of
15 * its contributors may be used to endorse or promote products derived
16 * from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR
22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
26 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
27 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 *
30 */
31/*
32 * NOTICE: This file was modified by McAfee Research in 2004 to introduce
33 * support for mandatory and extensible security protections. This notice
34 * is included in support of clause 2.2 (b) of the Apple Public License,
35 * Version 2.0.
36 */
37
38#include <sys/param.h>
39#include <sys/fcntl.h>
40#include <sys/kernel.h>
41#include <sys/lock.h>
42#include <sys/namei.h>
43#include <sys/proc_internal.h>
44#include <sys/kauth.h>
45#include <sys/queue.h>
46#include <sys/systm.h>
47#include <sys/time.h>
48#include <sys/ucred.h>
49#include <sys/uio.h>
50#include <sys/unistd.h>
51#include <sys/file_internal.h>
52#include <sys/vnode_internal.h>
53#include <sys/user.h>
54#include <sys/syscall.h>
55#include <sys/malloc.h>
56#include <sys/un.h>
57#include <sys/sysent.h>
58#include <sys/sysproto.h>
59#include <sys/vfs_context.h>
60#include <sys/domain.h>
61#include <sys/protosw.h>
62#include <sys/socketvar.h>
63
64#include <bsm/audit.h>
65#include <bsm/audit_internal.h>
66#include <bsm/audit_kevents.h>
67
68#include <security/audit/audit.h>
69#include <security/audit/audit_bsd.h>
70#include <security/audit/audit_private.h>
71
72#include <mach/host_priv.h>
73#include <mach/host_special_ports.h>
74#include <mach/audit_triggers_server.h>
75
76#include <kern/host.h>
b0d623f7 77#include <kern/zalloc.h>
b0d623f7
A
78#include <kern/sched_prim.h>
79
80#include <net/route.h>
81
82#include <netinet/in.h>
83#include <netinet/in_pcb.h>
84
85#if CONFIG_AUDIT
86MALLOC_DEFINE(M_AUDITDATA, "audit_data", "Audit data storage");
87MALLOC_DEFINE(M_AUDITPATH, "audit_path", "Audit path storage");
88MALLOC_DEFINE(M_AUDITTEXT, "audit_text", "Audit text storage");
f427ee49 89KALLOC_HEAP_DEFINE(KHEAP_AUDIT, "Audit", KHEAP_ID_DEFAULT);
b0d623f7
A
90
91/*
92 * Audit control settings that are set/read by system calls and are hence
93 * non-static.
94 *
95 * Define the audit control flags.
96 */
0a7de745
A
97int audit_enabled;
98int audit_suspended;
b0d623f7 99
0a7de745
A
100int audit_syscalls;
101au_class_t audit_kevent_mask;
b0d623f7 102
d9a64523
A
103/*
104 * The audit control mode is used to ensure configuration settings are only
105 * accepted from appropriate sources based on the current mode.
106 */
107au_ctlmode_t audit_ctl_mode;
108au_expire_after_t audit_expire_after;
109
b0d623f7
A
110/*
111 * Flags controlling behavior in low storage situations. Should we panic if
112 * a write fails? Should we fail stop if we're out of disk space?
113 */
0a7de745
A
114int audit_panic_on_write_fail;
115int audit_fail_stop;
116int audit_argv;
117int audit_arge;
b0d623f7
A
118
119/*
120 * Are we currently "failing stop" due to out of disk space?
121 */
0a7de745 122int audit_in_failure;
b0d623f7
A
123
124/*
125 * Global audit statistics.
126 */
0a7de745 127struct audit_fstat audit_fstat;
b0d623f7
A
128
129/*
130 * Preselection mask for non-attributable events.
131 */
0a7de745 132struct au_mask audit_nae_mask;
b0d623f7
A
133
134/*
135 * Mutex to protect global variables shared between various threads and
136 * processes.
137 */
0a7de745 138struct mtx audit_mtx;
b0d623f7
A
139
140/*
141 * Queue of audit records ready for delivery to disk. We insert new records
142 * at the tail, and remove records from the head. Also, a count of the
143 * number of records used for checking queue depth. In addition, a counter
144 * of records that we have allocated but are not yet in the queue, which is
145 * needed to estimate the total size of the combined set of records
146 * outstanding in the system.
147 */
0a7de745
A
148struct kaudit_queue audit_q;
149int audit_q_len;
150int audit_pre_q_len;
b0d623f7
A
151
152/*
153 * Audit queue control settings (minimum free, low/high water marks, etc.)
154 */
0a7de745 155struct au_qctrl audit_qctrl;
b0d623f7
A
156
157/*
158 * Condition variable to signal to the worker that it has work to do: either
159 * new records are in the queue, or a log replacement is taking place.
160 */
0a7de745 161struct cv audit_worker_cv;
b0d623f7
A
162
163/*
164 * Condition variable to signal when the worker is done draining the audit
165 * queue.
166 */
0a7de745 167struct cv audit_drain_cv;
b0d623f7
A
168
169/*
170 * Condition variable to flag when crossing the low watermark, meaning that
171 * threads blocked due to hitting the high watermark can wake up and continue
172 * to commit records.
173 */
0a7de745 174struct cv audit_watermark_cv;
b0d623f7
A
175
176/*
177 * Condition variable for auditing threads wait on when in fail-stop mode.
178 * Threads wait on this CV forever (and ever), never seeing the light of day
179 * again.
180 */
0a7de745 181static struct cv audit_fail_cv;
b0d623f7 182
f427ee49
A
183static ZONE_DECLARE(audit_record_zone, "audit_zone",
184 sizeof(struct kaudit_record), ZC_NONE);
b0d623f7
A
185
186/*
187 * Kernel audit information. This will store the current audit address
188 * or host information that the kernel will use when it's generating
189 * audit records. This data is modified by the A_GET{SET}KAUDIT auditon(2)
190 * command.
191 */
0a7de745
A
192static struct auditinfo_addr audit_kinfo;
193static struct rwlock audit_kinfo_lock;
b0d623f7 194
0a7de745
A
195#define KINFO_LOCK_INIT() rw_init(&audit_kinfo_lock, \
196 "audit_kinfo_lock")
197#define KINFO_RLOCK() rw_rlock(&audit_kinfo_lock)
198#define KINFO_WLOCK() rw_wlock(&audit_kinfo_lock)
199#define KINFO_RUNLOCK() rw_runlock(&audit_kinfo_lock)
200#define KINFO_WUNLOCK() rw_wunlock(&audit_kinfo_lock)
b0d623f7
A
201
202void
203audit_set_kinfo(struct auditinfo_addr *ak)
204{
b0d623f7
A
205 KASSERT(ak->ai_termid.at_type == AU_IPv4 ||
206 ak->ai_termid.at_type == AU_IPv6,
207 ("audit_set_kinfo: invalid address type"));
208
209 KINFO_WLOCK();
210 bcopy(ak, &audit_kinfo, sizeof(audit_kinfo));
211 KINFO_WUNLOCK();
212}
213
214void
215audit_get_kinfo(struct auditinfo_addr *ak)
216{
b0d623f7
A
217 KASSERT(audit_kinfo.ai_termid.at_type == AU_IPv4 ||
218 audit_kinfo.ai_termid.at_type == AU_IPv6,
219 ("audit_set_kinfo: invalid address type"));
220
221 KINFO_RLOCK();
222 bcopy(&audit_kinfo, ak, sizeof(*ak));
223 KINFO_RUNLOCK();
224}
225
226/*
227 * Construct an audit record for the passed thread.
228 */
229static void
230audit_record_ctor(proc_t p, struct kaudit_record *ar)
231{
232 kauth_cred_t cred;
233
234 bzero(ar, sizeof(*ar));
235 ar->k_ar.ar_magic = AUDIT_RECORD_MAGIC;
236 nanotime(&ar->k_ar.ar_starttime);
237
6d2010ae
A
238 if (PROC_NULL != p) {
239 cred = kauth_cred_proc_ref(p);
b0d623f7 240
6d2010ae 241 /*
0a7de745
A
242 * Export the subject credential.
243 */
6d2010ae
A
244 cru2x(cred, &ar->k_ar.ar_subj_cred);
245 ar->k_ar.ar_subj_ruid = kauth_cred_getruid(cred);
246 ar->k_ar.ar_subj_rgid = kauth_cred_getrgid(cred);
247 ar->k_ar.ar_subj_egid = kauth_cred_getgid(cred);
248 ar->k_ar.ar_subj_pid = p->p_pid;
249 ar->k_ar.ar_subj_auid = cred->cr_audit.as_aia_p->ai_auid;
250 ar->k_ar.ar_subj_asid = cred->cr_audit.as_aia_p->ai_asid;
251 bcopy(&cred->cr_audit.as_mask, &ar->k_ar.ar_subj_amask,
0a7de745 252 sizeof(struct au_mask));
6d2010ae
A
253 bcopy(&cred->cr_audit.as_aia_p->ai_termid,
254 &ar->k_ar.ar_subj_term_addr, sizeof(struct au_tid_addr));
255 kauth_cred_unref(&cred);
256 }
b0d623f7
A
257}
258
259static void
260audit_record_dtor(struct kaudit_record *ar)
261{
0a7de745 262 if (ar->k_ar.ar_arg_upath1 != NULL) {
b0d623f7 263 free(ar->k_ar.ar_arg_upath1, M_AUDITPATH);
0a7de745
A
264 }
265 if (ar->k_ar.ar_arg_upath2 != NULL) {
b0d623f7 266 free(ar->k_ar.ar_arg_upath2, M_AUDITPATH);
0a7de745
A
267 }
268 if (ar->k_ar.ar_arg_kpath1 != NULL) {
b0d623f7 269 free(ar->k_ar.ar_arg_kpath1, M_AUDITPATH);
0a7de745
A
270 }
271 if (ar->k_ar.ar_arg_kpath2 != NULL) {
b0d623f7 272 free(ar->k_ar.ar_arg_kpath2, M_AUDITPATH);
0a7de745
A
273 }
274 if (ar->k_ar.ar_arg_text != NULL) {
b0d623f7 275 free(ar->k_ar.ar_arg_text, M_AUDITTEXT);
0a7de745
A
276 }
277 if (ar->k_ar.ar_arg_opaque != NULL) {
b0d623f7 278 free(ar->k_ar.ar_arg_opaque, M_AUDITDATA);
0a7de745
A
279 }
280 if (ar->k_ar.ar_arg_data != NULL) {
b0d623f7 281 free(ar->k_ar.ar_arg_data, M_AUDITDATA);
0a7de745
A
282 }
283 if (ar->k_udata != NULL) {
b0d623f7 284 free(ar->k_udata, M_AUDITDATA);
0a7de745
A
285 }
286 if (ar->k_ar.ar_arg_argv != NULL) {
b0d623f7 287 free(ar->k_ar.ar_arg_argv, M_AUDITTEXT);
0a7de745
A
288 }
289 if (ar->k_ar.ar_arg_envv != NULL) {
b0d623f7 290 free(ar->k_ar.ar_arg_envv, M_AUDITTEXT);
0a7de745 291 }
d9a64523 292 audit_identity_info_destruct(&ar->k_ar.ar_arg_identity);
b0d623f7
A
293}
294
295/*
296 * Initialize the Audit subsystem: configuration state, work queue,
297 * synchronization primitives, worker thread, and trigger device node. Also
298 * call into the BSM assembly code to initialize it.
299 */
300void
301audit_init(void)
302{
b0d623f7
A
303 audit_enabled = 0;
304 audit_syscalls = 0;
305 audit_kevent_mask = 0;
306 audit_suspended = 0;
307 audit_panic_on_write_fail = 0;
308 audit_fail_stop = 0;
309 audit_in_failure = 0;
310 audit_argv = 0;
311 audit_arge = 0;
d9a64523
A
312 audit_ctl_mode = AUDIT_CTLMODE_NORMAL;
313 audit_expire_after.age = 0;
314 audit_expire_after.size = 0;
315 audit_expire_after.op_type = AUDIT_EXPIRE_OP_AND;
b0d623f7 316
0a7de745 317 audit_fstat.af_filesz = 0; /* '0' means unset, unbounded. */
b0d623f7
A
318 audit_fstat.af_currsz = 0;
319 audit_nae_mask.am_success = 0;
320 audit_nae_mask.am_failure = 0;
321
322 TAILQ_INIT(&audit_q);
323 audit_q_len = 0;
324 audit_pre_q_len = 0;
325 audit_qctrl.aq_hiwater = AQ_HIWATER;
326 audit_qctrl.aq_lowater = AQ_LOWATER;
327 audit_qctrl.aq_bufsz = AQ_BUFSZ;
328 audit_qctrl.aq_minfree = AU_FS_MINFREE;
329
330 audit_kinfo.ai_termid.at_type = AU_IPv4;
331 audit_kinfo.ai_termid.at_addr[0] = INADDR_ANY;
332
333 mtx_init(&audit_mtx, "audit_mtx", NULL, MTX_DEF);
334 KINFO_LOCK_INIT();
335 cv_init(&audit_worker_cv, "audit_worker_cv");
336 cv_init(&audit_drain_cv, "audit_drain_cv");
337 cv_init(&audit_watermark_cv, "audit_watermark_cv");
338 cv_init(&audit_fail_cv, "audit_fail_cv");
339
b0d623f7
A
340 /* Init audit session subsystem. */
341 audit_session_init();
342
343 /* Initialize the BSM audit subsystem. */
344 kau_init();
345
346 /* audit_trigger_init(); */
347
348 /* Start audit worker thread. */
349 (void) audit_pipe_init();
350
351 /* Start audit worker thread. */
352 audit_worker_init();
353}
354
355/*
356 * Drain the audit queue and close the log at shutdown. Note that this can
357 * be called both from the system shutdown path and also from audit
358 * configuration syscalls, so 'arg' and 'howto' are ignored.
359 */
360void
361audit_shutdown(void)
362{
b0d623f7
A
363 audit_rotate_vnode(NULL, NULL);
364}
365
366/*
367 * Return the current thread's audit record, if any.
368 */
6d2010ae 369struct kaudit_record *
b0d623f7
A
370currecord(void)
371{
0a7de745 372 return curthread()->uu_ar;
b0d623f7
A
373}
374
375/*
376 * XXXAUDIT: There are a number of races present in the code below due to
377 * release and re-grab of the mutex. The code should be revised to become
378 * slightly less racy.
379 *
380 * XXXAUDIT: Shouldn't there be logic here to sleep waiting on available
381 * pre_q space, suspending the system call until there is room?
382 */
383struct kaudit_record *
384audit_new(int event, proc_t p, __unused struct uthread *uthread)
385{
386 struct kaudit_record *ar;
387 int no_record;
6d2010ae 388 int audit_override;
b0d623f7 389
6d2010ae
A
390 /*
391 * Override the audit_suspended and audit_enabled if it always
392 * audits session events.
393 *
394 * XXXss - This really needs to be a generalized call to a filter
395 * interface so if other things that use the audit subsystem in the
396 * future can simply plugged in.
397 */
398 audit_override = (AUE_SESSION_START == event ||
399 AUE_SESSION_UPDATE == event || AUE_SESSION_END == event ||
400 AUE_SESSION_CLOSE == event);
0a7de745 401
b0d623f7
A
402 mtx_lock(&audit_mtx);
403 no_record = (audit_suspended || !audit_enabled);
404 mtx_unlock(&audit_mtx);
0a7de745
A
405 if (!audit_override && no_record) {
406 return NULL;
407 }
b0d623f7
A
408
409 /*
410 * Initialize the audit record header.
411 * XXX: We may want to fail-stop if allocation fails.
412 *
413 * Note: the number of outstanding uncommitted audit records is
414 * limited to the number of concurrent threads servicing system calls
415 * in the kernel.
416 */
417 ar = zalloc(audit_record_zone);
0a7de745 418 if (ar == NULL) {
b0d623f7 419 return NULL;
0a7de745 420 }
b0d623f7
A
421 audit_record_ctor(p, ar);
422 ar->k_ar.ar_event = event;
423
424#if CONFIG_MACF
6d2010ae
A
425 if (PROC_NULL != p) {
426 if (audit_mac_new(p, ar) != 0) {
427 zfree(audit_record_zone, ar);
0a7de745 428 return NULL;
6d2010ae 429 }
0a7de745 430 } else {
6d2010ae 431 ar->k_ar.ar_mac_records = NULL;
0a7de745 432 }
b0d623f7
A
433#endif
434
435 mtx_lock(&audit_mtx);
436 audit_pre_q_len++;
437 mtx_unlock(&audit_mtx);
438
0a7de745 439 return ar;
b0d623f7
A
440}
441
442void
443audit_free(struct kaudit_record *ar)
444{
b0d623f7
A
445 audit_record_dtor(ar);
446#if CONFIG_MACF
0a7de745 447 if (NULL != ar->k_ar.ar_mac_records) {
6d2010ae 448 audit_mac_free(ar);
0a7de745 449 }
b0d623f7
A
450#endif
451 zfree(audit_record_zone, ar);
452}
453
454void
455audit_commit(struct kaudit_record *ar, int error, int retval)
456{
457 au_event_t event;
458 au_class_t class;
459 au_id_t auid;
460 int sorf;
461 struct au_mask *aumask;
6d2010ae 462 int audit_override;
b0d623f7 463
0a7de745 464 if (ar == NULL) {
b0d623f7 465 return;
0a7de745 466 }
b0d623f7
A
467
468 /*
469 * Decide whether to commit the audit record by checking the error
470 * value from the system call and using the appropriate audit mask.
471 */
0a7de745 472 if (ar->k_ar.ar_subj_auid == AU_DEFAUDITID) {
b0d623f7 473 aumask = &audit_nae_mask;
0a7de745 474 } else {
b0d623f7 475 aumask = &ar->k_ar.ar_subj_amask;
0a7de745 476 }
b0d623f7 477
0a7de745 478 if (error) {
b0d623f7 479 sorf = AU_PRS_FAILURE;
0a7de745 480 } else {
b0d623f7 481 sorf = AU_PRS_SUCCESS;
0a7de745 482 }
b0d623f7 483
0a7de745 484 switch (ar->k_ar.ar_event) {
b0d623f7
A
485 case AUE_OPEN_RWTC:
486 /*
487 * The open syscall always writes a AUE_OPEN_RWTC event;
488 * change it to the proper type of event based on the flags
489 * and the error value.
490 */
491 ar->k_ar.ar_event = audit_flags_and_error_to_openevent(
0a7de745 492 ar->k_ar.ar_arg_fflags, error);
b0d623f7
A
493 break;
494
495 case AUE_OPEN_EXTENDED_RWTC:
496 /*
497 * The open_extended syscall always writes a
498 * AUE_OPEN_EXTENDEDRWTC event; change it to the proper type of
499 * event based on the flags and the error value.
500 */
501 ar->k_ar.ar_event = audit_flags_and_error_to_openextendedevent(
0a7de745 502 ar->k_ar.ar_arg_fflags, error);
b0d623f7
A
503 break;
504
fe8ab488
A
505 case AUE_OPENAT_RWTC:
506 /*
507 * The openat syscall always writes a
508 * AUE_OPENAT_RWTC event; change it to the proper type of
509 * event based on the flags and the error value.
510 */
511 ar->k_ar.ar_event = audit_flags_and_error_to_openatevent(
0a7de745 512 ar->k_ar.ar_arg_fflags, error);
fe8ab488
A
513 break;
514
515 case AUE_OPENBYID_RWT:
516 /*
517 * The openbyid syscall always writes a
518 * AUE_OPENBYID_RWT event; change it to the proper type of
519 * event based on the flags and the error value.
520 */
521 ar->k_ar.ar_event = audit_flags_and_error_to_openbyidevent(
0a7de745 522 ar->k_ar.ar_arg_fflags, error);
fe8ab488
A
523 break;
524
b0d623f7
A
525 case AUE_SYSCTL:
526 ar->k_ar.ar_event = audit_ctlname_to_sysctlevent(
0a7de745 527 ar->k_ar.ar_arg_ctlname, ar->k_ar.ar_valid_arg);
b0d623f7
A
528 break;
529
530 case AUE_AUDITON:
531 /* Convert the auditon() command to an event. */
532 ar->k_ar.ar_event = auditon_command_event(ar->k_ar.ar_arg_cmd);
533 break;
534
535 case AUE_FCNTL:
536 /* Convert some fcntl() commands to their own events. */
537 ar->k_ar.ar_event = audit_fcntl_command_event(
0a7de745 538 ar->k_ar.ar_arg_cmd, ar->k_ar.ar_arg_fflags, error);
b0d623f7
A
539 break;
540 }
541
542 auid = ar->k_ar.ar_subj_auid;
543 event = ar->k_ar.ar_event;
544 class = au_event_class(event);
545
6d2010ae
A
546 /*
547 * See if we need to override the audit_suspend and audit_enabled
548 * flags.
549 *
550 * XXXss - This check needs to be generalized so new filters can
551 * easily be added.
552 */
553 audit_override = (AUE_SESSION_START == event ||
554 AUE_SESSION_UPDATE == event || AUE_SESSION_END == event ||
555 AUE_SESSION_CLOSE == event);
556
b0d623f7 557 ar->k_ar_commit |= AR_COMMIT_KERNEL;
0a7de745 558 if (au_preselect(event, class, aumask, sorf) != 0) {
b0d623f7 559 ar->k_ar_commit |= AR_PRESELECT_TRAIL;
0a7de745 560 }
b0d623f7 561 if (audit_pipe_preselect(auid, event, class, sorf,
0a7de745 562 ar->k_ar_commit & AR_PRESELECT_TRAIL) != 0) {
b0d623f7 563 ar->k_ar_commit |= AR_PRESELECT_PIPE;
0a7de745 564 }
b0d623f7 565 if ((ar->k_ar_commit & (AR_PRESELECT_TRAIL | AR_PRESELECT_PIPE |
6d2010ae
A
566 AR_PRESELECT_USER_TRAIL | AR_PRESELECT_USER_PIPE |
567 AR_PRESELECT_FILTER)) == 0) {
b0d623f7
A
568 mtx_lock(&audit_mtx);
569 audit_pre_q_len--;
570 mtx_unlock(&audit_mtx);
571 audit_free(ar);
572 return;
573 }
574
575 ar->k_ar.ar_errno = error;
576 ar->k_ar.ar_retval = retval;
577 nanotime(&ar->k_ar.ar_endtime);
578
579 /*
580 * Note: it could be that some records initiated while audit was
581 * enabled should still be committed?
582 */
583 mtx_lock(&audit_mtx);
6d2010ae 584 if (!audit_override && (audit_suspended || !audit_enabled)) {
b0d623f7
A
585 audit_pre_q_len--;
586 mtx_unlock(&audit_mtx);
587 audit_free(ar);
588 return;
589 }
590
591 /*
592 * Constrain the number of committed audit records based on the
593 * configurable parameter.
594 */
0a7de745 595 while (audit_q_len >= audit_qctrl.aq_hiwater) {
b0d623f7 596 cv_wait(&audit_watermark_cv, &audit_mtx);
0a7de745 597 }
b0d623f7
A
598
599 TAILQ_INSERT_TAIL(&audit_q, ar, k_q);
600 audit_q_len++;
601 audit_pre_q_len--;
602 cv_signal(&audit_worker_cv);
603 mtx_unlock(&audit_mtx);
604}
605
606/*
607 * audit_syscall_enter() is called on entry to each system call. It is
608 * responsible for deciding whether or not to audit the call (preselection),
609 * and if so, allocating a per-thread audit record. audit_new() will fill in
610 * basic thread/credential properties.
611 */
612void
613audit_syscall_enter(unsigned int code, proc_t proc, struct uthread *uthread)
614{
615 struct au_mask *aumask;
616 au_class_t class;
617 au_event_t event;
618 au_id_t auid;
619 kauth_cred_t cred;
620
621 /*
622 * In FreeBSD, each ABI has its own system call table, and hence
623 * mapping of system call codes to audit events. Convert the code to
624 * an audit event identifier using the process system call table
625 * reference. In Darwin, there's only one, so we use the global
626 * symbol for the system call table. No audit record is generated
627 * for bad system calls, as no operation has been performed.
628 *
629 * In Mac OS X, the audit events are stored in a table seperate from
630 * the syscall table(s). This table is generated by makesyscalls.sh
631 * from syscalls.master and stored in audit_kevents.c.
632 */
0a7de745 633 if (code >= nsysent) {
b0d623f7 634 return;
0a7de745 635 }
b0d623f7 636 event = sys_au_event[code];
0a7de745 637 if (event == AUE_NULL) {
b0d623f7 638 return;
0a7de745 639 }
b0d623f7
A
640
641 KASSERT(uthread->uu_ar == NULL,
642 ("audit_syscall_enter: uthread->uu_ar != NULL"));
643
644 /*
645 * Check which audit mask to use; either the kernel non-attributable
646 * event mask or the process audit mask.
647 */
648 cred = kauth_cred_proc_ref(proc);
649 auid = cred->cr_audit.as_aia_p->ai_auid;
0a7de745 650 if (auid == AU_DEFAUDITID) {
b0d623f7 651 aumask = &audit_nae_mask;
0a7de745 652 } else {
b0d623f7 653 aumask = &cred->cr_audit.as_mask;
0a7de745 654 }
b0d623f7
A
655
656 /*
657 * Allocate an audit record, if preselection allows it, and store in
658 * the thread for later use.
659 */
660 class = au_event_class(event);
661#if CONFIG_MACF
662 /*
663 * Note: audit_mac_syscall_enter() may call audit_new() and allocate
664 * memory for the audit record (uu_ar).
665 */
0a7de745 666 if (audit_mac_syscall_enter(code, proc, uthread, cred, event) == 0) {
b0d623f7 667 goto out;
0a7de745 668 }
b0d623f7
A
669#endif
670 if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
671 /*
672 * If we're out of space and need to suspend unprivileged
673 * processes, do that here rather than trying to allocate
674 * another audit record.
675 *
676 * Note: we might wish to be able to continue here in the
677 * future, if the system recovers. That should be possible
678 * by means of checking the condition in a loop around
679 * cv_wait(). It might be desirable to reevaluate whether an
680 * audit record is still required for this event by
681 * re-calling au_preselect().
682 */
683 if (audit_in_failure &&
684 suser(cred, &proc->p_acflag) != 0) {
685 cv_wait(&audit_fail_cv, &audit_mtx);
686 panic("audit_failing_stop: thread continued");
687 }
0a7de745 688 if (uthread->uu_ar == NULL) {
b0d623f7 689 uthread->uu_ar = audit_new(event, proc, uthread);
0a7de745 690 }
b0d623f7 691 } else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
0a7de745 692 if (uthread->uu_ar == NULL) {
b0d623f7 693 uthread->uu_ar = audit_new(event, proc, uthread);
0a7de745
A
694 }
695 }
b0d623f7 696
d9a64523
A
697 /*
698 * All audited events will contain an identity
699 *
700 * Note: Identity should be obtained prior to the syscall implementation
701 * being called to handle cases like execve(2) where the process changes
702 */
703 AUDIT_ARG(identity);
704
b0d623f7
A
705out:
706 kauth_cred_unref(&cred);
707}
708
709/*
710 * audit_syscall_exit() is called from the return of every system call, or in
711 * the event of exit1(), during the execution of exit1(). It is responsible
712 * for committing the audit record, if any, along with return condition.
713 *
714 * Note: The audit_syscall_exit() parameter list was modified to support
715 * mac_audit_check_postselect(), which requires the syscall number.
716 */
717#if CONFIG_MACF
718void
719audit_syscall_exit(unsigned int code, int error, __unused proc_t proc,
720 struct uthread *uthread)
721#else
722void
723audit_syscall_exit(int error, __unsed proc_t proc, struct uthread *uthread)
724#endif
725{
726 int retval;
727
728 /*
729 * Commit the audit record as desired; once we pass the record into
730 * audit_commit(), the memory is owned by the audit subsystem. The
731 * return value from the system call is stored on the user thread.
732 * If there was an error, the return value is set to -1, imitating
733 * the behavior of the cerror routine.
734 */
0a7de745 735 if (error) {
b0d623f7 736 retval = -1;
0a7de745 737 } else {
b0d623f7 738 retval = uthread->uu_rval[0];
0a7de745 739 }
b0d623f7
A
740
741#if CONFIG_MACF
0a7de745 742 if (audit_mac_syscall_exit(code, uthread, error, retval) != 0) {
b0d623f7 743 goto out;
0a7de745 744 }
b0d623f7
A
745#endif
746 audit_commit(uthread->uu_ar, error, retval);
747
748out:
749 uthread->uu_ar = NULL;
750}
751
94ff46dc
A
752/*
753 * For system calls such as posix_spawn(2) the sub operations (i.e., file actions
754 * and port actions) need to be audited as their own events. Like with system
755 * calls we need to determine if the sub operation needs to be audited by
756 * examining preselection masks.
757 */
758void
759audit_subcall_enter(au_event_t event, proc_t proc, struct uthread *uthread)
760{
761 struct au_mask *aumask;
762 au_class_t class;
763 au_id_t auid;
764 kauth_cred_t cred;
765
766 /*
767 * Check which audit mask to use; either the kernel non-attributable
768 * event mask or the process audit mask.
769 */
770 cred = kauth_cred_proc_ref(proc);
771 auid = cred->cr_audit.as_aia_p->ai_auid;
772 if (auid == AU_DEFAUDITID) {
773 aumask = &audit_nae_mask;
774 } else {
775 aumask = &cred->cr_audit.as_mask;
776 }
777
778 /*
779 * Allocate an audit record, if preselection allows it, and store in
780 * the thread for later use.
781 */
782 class = au_event_class(event);
783
784 if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
785 /*
786 * If we're out of space and need to suspend unprivileged
787 * processes, do that here rather than trying to allocate
788 * another audit record.
789 *
790 * Note: we might wish to be able to continue here in the
791 * future, if the system recovers. That should be possible
792 * by means of checking the condition in a loop around
793 * cv_wait(). It might be desirable to reevaluate whether an
794 * audit record is still required for this event by
795 * re-calling au_preselect().
796 */
797 if (audit_in_failure &&
798 suser(cred, &proc->p_acflag) != 0) {
799 cv_wait(&audit_fail_cv, &audit_mtx);
800 panic("audit_failing_stop: thread continued");
801 }
802 if (uthread->uu_ar == NULL) {
803 uthread->uu_ar = audit_new(event, proc, uthread);
804 }
805 } else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
806 if (uthread->uu_ar == NULL) {
807 uthread->uu_ar = audit_new(event, proc, uthread);
808 }
809 }
810
811 kauth_cred_unref(&cred);
812}
813
814void
815audit_subcall_exit(int error, struct uthread *uthread)
816{
817 /* A subcall doesn't have a return value so always zero. */
818 audit_commit(uthread->uu_ar, error, 0 /* retval */);
819
820 uthread->uu_ar = NULL;
821}
822
b0d623f7
A
823/*
824 * Calls to set up and tear down audit structures used during Mach system
825 * calls.
826 */
827void
828audit_mach_syscall_enter(unsigned short event)
829{
830 struct uthread *uthread;
831 proc_t proc;
832 struct au_mask *aumask;
833 kauth_cred_t cred;
834 au_class_t class;
835 au_id_t auid;
836
0a7de745 837 if (event == AUE_NULL) {
b0d623f7 838 return;
0a7de745 839 }
b0d623f7
A
840
841 uthread = curthread();
0a7de745 842 if (uthread == NULL) {
b0d623f7 843 return;
0a7de745 844 }
b0d623f7
A
845
846 proc = current_proc();
0a7de745 847 if (proc == NULL) {
b0d623f7 848 return;
0a7de745 849 }
b0d623f7
A
850
851 KASSERT(uthread->uu_ar == NULL,
852 ("audit_mach_syscall_enter: uthread->uu_ar != NULL"));
853
854 cred = kauth_cred_proc_ref(proc);
855 auid = cred->cr_audit.as_aia_p->ai_auid;
856
857 /*
858 * Check which audit mask to use; either the kernel non-attributable
859 * event mask or the process audit mask.
860 */
0a7de745 861 if (auid == AU_DEFAUDITID) {
b0d623f7 862 aumask = &audit_nae_mask;
0a7de745 863 } else {
b0d623f7 864 aumask = &cred->cr_audit.as_mask;
0a7de745 865 }
b0d623f7
A
866
867 /*
868 * Allocate an audit record, if desired, and store in the BSD thread
869 * for later use.
870 */
871 class = au_event_class(event);
0a7de745 872 if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
b0d623f7 873 uthread->uu_ar = audit_new(event, proc, uthread);
0a7de745 874 } else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
b0d623f7 875 uthread->uu_ar = audit_new(event, proc, uthread);
0a7de745 876 } else {
b0d623f7 877 uthread->uu_ar = NULL;
0a7de745 878 }
b0d623f7
A
879
880 kauth_cred_unref(&cred);
881}
882
883void
884audit_mach_syscall_exit(int retval, struct uthread *uthread)
885{
886 /*
887 * The error code from Mach system calls is the same as the
888 * return value
889 */
890 /* XXX Is the above statement always true? */
891 audit_commit(uthread->uu_ar, retval, retval);
892 uthread->uu_ar = NULL;
893}
894
895/*
896 * kau_will_audit can be used by a security policy to determine
897 * if an audit record will be stored, reducing wasted memory allocation
898 * and string handling.
899 */
900int
901kau_will_audit(void)
902{
0a7de745 903 return audit_enabled && currecord() != NULL;
b0d623f7
A
904}
905
39037602 906#if CONFIG_COREDUMP
b0d623f7
A
907void
908audit_proc_coredump(proc_t proc, char *path, int errcode)
909{
910 struct kaudit_record *ar;
911 struct au_mask *aumask;
912 au_class_t class;
913 int ret, sorf;
914 char **pathp;
915 au_id_t auid;
916 kauth_cred_t my_cred;
917 struct uthread *uthread;
918
919 ret = 0;
920
921 /*
922 * Make sure we are using the correct preselection mask.
923 */
924 my_cred = kauth_cred_proc_ref(proc);
925 auid = my_cred->cr_audit.as_aia_p->ai_auid;
0a7de745 926 if (auid == AU_DEFAUDITID) {
b0d623f7 927 aumask = &audit_nae_mask;
0a7de745 928 } else {
b0d623f7 929 aumask = &my_cred->cr_audit.as_mask;
0a7de745 930 }
b0d623f7
A
931 kauth_cred_unref(&my_cred);
932 /*
933 * It's possible for coredump(9) generation to fail. Make sure that
934 * we handle this case correctly for preselection.
935 */
0a7de745 936 if (errcode != 0) {
b0d623f7 937 sorf = AU_PRS_FAILURE;
0a7de745 938 } else {
b0d623f7 939 sorf = AU_PRS_SUCCESS;
0a7de745 940 }
b0d623f7
A
941 class = au_event_class(AUE_CORE);
942 if (au_preselect(AUE_CORE, class, aumask, sorf) == 0 &&
0a7de745 943 audit_pipe_preselect(auid, AUE_CORE, class, sorf, 0) == 0) {
b0d623f7 944 return;
0a7de745 945 }
b0d623f7
A
946 /*
947 * If we are interested in seeing this audit record, allocate it.
948 * Where possible coredump records should contain a pathname and arg32
949 * (signal) tokens.
950 */
951 uthread = curthread();
952 ar = audit_new(AUE_CORE, proc, uthread);
f427ee49
A
953 if (ar == NULL) {
954 return;
955 }
b0d623f7
A
956 if (path != NULL) {
957 pathp = &ar->k_ar.ar_arg_upath1;
958 *pathp = malloc(MAXPATHLEN, M_AUDITPATH, M_WAITOK);
959 if (audit_canon_path(vfs_context_cwd(vfs_context_current()), path,
0a7de745 960 *pathp)) {
b0d623f7 961 free(*pathp, M_AUDITPATH);
0a7de745 962 } else {
b0d623f7 963 ARG_SET_VALID(ar, ARG_UPATH1);
0a7de745 964 }
b0d623f7
A
965 }
966 ar->k_ar.ar_arg_signum = proc->p_sigacts->ps_sig;
967 ARG_SET_VALID(ar, ARG_SIGNUM);
0a7de745 968 if (errcode != 0) {
b0d623f7 969 ret = 1;
0a7de745 970 }
b0d623f7
A
971 audit_commit(ar, errcode, ret);
972}
39037602 973#endif /* CONFIG_COREDUMP */
b0d623f7 974#endif /* CONFIG_AUDIT */