1/*-
2 * Copyright (c) 1999-2009 Apple Inc.
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>
77#include <kern/kalloc.h>
78#include <kern/zalloc.h>
79#include <kern/sched_prim.h>
80
81#include <net/route.h>
82
83#include <netinet/in.h>
84#include <netinet/in_pcb.h>
85
86#if CONFIG_AUDIT
87MALLOC_DEFINE(M_AUDITDATA, "audit_data", "Audit data storage");
88MALLOC_DEFINE(M_AUDITPATH, "audit_path", "Audit path storage");
89MALLOC_DEFINE(M_AUDITTEXT, "audit_text", "Audit text storage");
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 */
97int audit_enabled;
98int audit_suspended;
99
100int audit_syscalls;
101au_class_t audit_kevent_mask;
102
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
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 */
114int audit_panic_on_write_fail;
115int audit_fail_stop;
116int audit_argv;
117int audit_arge;
118
119/*
120 * Are we currently "failing stop" due to out of disk space?
121 */
122int audit_in_failure;
123
124/*
125 * Global audit statistics.
126 */
127struct audit_fstat audit_fstat;
128
129/*
130 * Preselection mask for non-attributable events.
131 */
132struct au_mask audit_nae_mask;
133
134/*
135 * Mutex to protect global variables shared between various threads and
136 * processes.
137 */
138struct mtx audit_mtx;
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 */
148struct kaudit_queue audit_q;
149int audit_q_len;
150int audit_pre_q_len;
151
152/*
153 * Audit queue control settings (minimum free, low/high water marks, etc.)
154 */
155struct au_qctrl audit_qctrl;
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 */
161struct cv audit_worker_cv;
162
163/*
164 * Condition variable to signal when the worker is done draining the audit
165 * queue.
166 */
167struct cv audit_drain_cv;
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 */
174struct cv audit_watermark_cv;
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 */
181static struct cv audit_fail_cv;
182
183static zone_t audit_record_zone;
184
185/*
186 * Kernel audit information. This will store the current audit address
187 * or host information that the kernel will use when it's generating
188 * audit records. This data is modified by the A_GET{SET}KAUDIT auditon(2)
189 * command.
190 */
191static struct auditinfo_addr audit_kinfo;
192static struct rwlock audit_kinfo_lock;
193
194#define KINFO_LOCK_INIT() rw_init(&audit_kinfo_lock, \
195 "audit_kinfo_lock")
196#define KINFO_RLOCK() rw_rlock(&audit_kinfo_lock)
197#define KINFO_WLOCK() rw_wlock(&audit_kinfo_lock)
198#define KINFO_RUNLOCK() rw_runlock(&audit_kinfo_lock)
199#define KINFO_WUNLOCK() rw_wunlock(&audit_kinfo_lock)
200
201void
202audit_set_kinfo(struct auditinfo_addr *ak)
203{
204
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{
217
218 KASSERT(audit_kinfo.ai_termid.at_type == AU_IPv4 ||
219 audit_kinfo.ai_termid.at_type == AU_IPv6,
220 ("audit_set_kinfo: invalid address type"));
221
222 KINFO_RLOCK();
223 bcopy(&audit_kinfo, ak, sizeof(*ak));
224 KINFO_RUNLOCK();
225}
226
227/*
228 * Construct an audit record for the passed thread.
229 */
230static void
231audit_record_ctor(proc_t p, struct kaudit_record *ar)
232{
233 kauth_cred_t cred;
234
235 bzero(ar, sizeof(*ar));
236 ar->k_ar.ar_magic = AUDIT_RECORD_MAGIC;
237 nanotime(&ar->k_ar.ar_starttime);
238
239 if (PROC_NULL != p) {
240 cred = kauth_cred_proc_ref(p);
241
242 /*
243 * Export the subject credential.
244 */
245 cru2x(cred, &ar->k_ar.ar_subj_cred);
246 ar->k_ar.ar_subj_ruid = kauth_cred_getruid(cred);
247 ar->k_ar.ar_subj_rgid = kauth_cred_getrgid(cred);
248 ar->k_ar.ar_subj_egid = kauth_cred_getgid(cred);
249 ar->k_ar.ar_subj_pid = p->p_pid;
250 ar->k_ar.ar_subj_auid = cred->cr_audit.as_aia_p->ai_auid;
251 ar->k_ar.ar_subj_asid = cred->cr_audit.as_aia_p->ai_asid;
252 bcopy(&cred->cr_audit.as_mask, &ar->k_ar.ar_subj_amask,
253 sizeof(struct au_mask));
254 bcopy(&cred->cr_audit.as_aia_p->ai_termid,
255 &ar->k_ar.ar_subj_term_addr, sizeof(struct au_tid_addr));
256 kauth_cred_unref(&cred);
257 }
258}
259
260static void
261audit_record_dtor(struct kaudit_record *ar)
262{
263
264 if (ar->k_ar.ar_arg_upath1 != NULL)
265 free(ar->k_ar.ar_arg_upath1, M_AUDITPATH);
266 if (ar->k_ar.ar_arg_upath2 != NULL)
267 free(ar->k_ar.ar_arg_upath2, M_AUDITPATH);
268 if (ar->k_ar.ar_arg_kpath1 != NULL)
269 free(ar->k_ar.ar_arg_kpath1, M_AUDITPATH);
270 if (ar->k_ar.ar_arg_kpath2 != NULL)
271 free(ar->k_ar.ar_arg_kpath2, M_AUDITPATH);
272 if (ar->k_ar.ar_arg_text != NULL)
273 free(ar->k_ar.ar_arg_text, M_AUDITTEXT);
274 if (ar->k_ar.ar_arg_opaque != NULL)
275 free(ar->k_ar.ar_arg_opaque, M_AUDITDATA);
276 if (ar->k_ar.ar_arg_data != NULL)
277 free(ar->k_ar.ar_arg_data, M_AUDITDATA);
278 if (ar->k_udata != NULL)
279 free(ar->k_udata, M_AUDITDATA);
280 if (ar->k_ar.ar_arg_argv != NULL)
281 free(ar->k_ar.ar_arg_argv, M_AUDITTEXT);
282 if (ar->k_ar.ar_arg_envv != NULL)
283 free(ar->k_ar.ar_arg_envv, M_AUDITTEXT);
284 audit_identity_info_destruct(&ar->k_ar.ar_arg_identity);
285}
286
287/*
288 * Initialize the Audit subsystem: configuration state, work queue,
289 * synchronization primitives, worker thread, and trigger device node. Also
290 * call into the BSM assembly code to initialize it.
291 */
292void
293audit_init(void)
294{
295
296 audit_enabled = 0;
297 audit_syscalls = 0;
298 audit_kevent_mask = 0;
299 audit_suspended = 0;
300 audit_panic_on_write_fail = 0;
301 audit_fail_stop = 0;
302 audit_in_failure = 0;
303 audit_argv = 0;
304 audit_arge = 0;
305 audit_ctl_mode = AUDIT_CTLMODE_NORMAL;
306 audit_expire_after.age = 0;
307 audit_expire_after.size = 0;
308 audit_expire_after.op_type = AUDIT_EXPIRE_OP_AND;
309
310 audit_fstat.af_filesz = 0; /* '0' means unset, unbounded. */
311 audit_fstat.af_currsz = 0;
312 audit_nae_mask.am_success = 0;
313 audit_nae_mask.am_failure = 0;
314
315 TAILQ_INIT(&audit_q);
316 audit_q_len = 0;
317 audit_pre_q_len = 0;
318 audit_qctrl.aq_hiwater = AQ_HIWATER;
319 audit_qctrl.aq_lowater = AQ_LOWATER;
320 audit_qctrl.aq_bufsz = AQ_BUFSZ;
321 audit_qctrl.aq_minfree = AU_FS_MINFREE;
322
323 audit_kinfo.ai_termid.at_type = AU_IPv4;
324 audit_kinfo.ai_termid.at_addr[0] = INADDR_ANY;
325
326 _audit_lck_grp_init();
327 mtx_init(&audit_mtx, "audit_mtx", NULL, MTX_DEF);
328 KINFO_LOCK_INIT();
329 cv_init(&audit_worker_cv, "audit_worker_cv");
330 cv_init(&audit_drain_cv, "audit_drain_cv");
331 cv_init(&audit_watermark_cv, "audit_watermark_cv");
332 cv_init(&audit_fail_cv, "audit_fail_cv");
333
334 audit_record_zone = zinit(sizeof(struct kaudit_record),
335 AQ_HIWATER*sizeof(struct kaudit_record), 8192, "audit_zone");
336#if CONFIG_MACF
337 audit_mac_init();
338#endif
339 /* Init audit session subsystem. */
340 audit_session_init();
341
342 /* Initialize the BSM audit subsystem. */
343 kau_init();
344
345 /* audit_trigger_init(); */
346
347 /* Start audit worker thread. */
348 (void) audit_pipe_init();
349
350 /* Start audit worker thread. */
351 audit_worker_init();
352}
353
354/*
355 * Drain the audit queue and close the log at shutdown. Note that this can
356 * be called both from the system shutdown path and also from audit
357 * configuration syscalls, so 'arg' and 'howto' are ignored.
358 */
359void
360audit_shutdown(void)
361{
362
363 audit_rotate_vnode(NULL, NULL);
364}
365
366/*
367 * Return the current thread's audit record, if any.
368 */
369struct kaudit_record *
370currecord(void)
371{
372
373 return (curthread()->uu_ar);
374}
375
376/*
377 * XXXAUDIT: There are a number of races present in the code below due to
378 * release and re-grab of the mutex. The code should be revised to become
379 * slightly less racy.
380 *
381 * XXXAUDIT: Shouldn't there be logic here to sleep waiting on available
382 * pre_q space, suspending the system call until there is room?
383 */
384struct kaudit_record *
385audit_new(int event, proc_t p, __unused struct uthread *uthread)
386{
387 struct kaudit_record *ar;
388 int no_record;
389 int audit_override;
390
391 /*
392 * Override the audit_suspended and audit_enabled if it always
393 * audits session events.
394 *
395 * XXXss - This really needs to be a generalized call to a filter
396 * interface so if other things that use the audit subsystem in the
397 * future can simply plugged in.
398 */
399 audit_override = (AUE_SESSION_START == event ||
400 AUE_SESSION_UPDATE == event || AUE_SESSION_END == event ||
401 AUE_SESSION_CLOSE == event);
402
403 mtx_lock(&audit_mtx);
404 no_record = (audit_suspended || !audit_enabled);
405 mtx_unlock(&audit_mtx);
406 if (!audit_override && no_record)
407 return (NULL);
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);
418 if (ar == NULL)
419 return NULL;
420 audit_record_ctor(p, ar);
421 ar->k_ar.ar_event = event;
422
423#if CONFIG_MACF
424 if (PROC_NULL != p) {
425 if (audit_mac_new(p, ar) != 0) {
426 zfree(audit_record_zone, ar);
427 return (NULL);
428 }
429 } else
430 ar->k_ar.ar_mac_records = NULL;
431#endif
432
433 mtx_lock(&audit_mtx);
434 audit_pre_q_len++;
435 mtx_unlock(&audit_mtx);
436
437 return (ar);
438}
439
440void
441audit_free(struct kaudit_record *ar)
442{
443
444 audit_record_dtor(ar);
445#if CONFIG_MACF
446 if (NULL != ar->k_ar.ar_mac_records)
447 audit_mac_free(ar);
448#endif
449 zfree(audit_record_zone, ar);
450}
451
452void
453audit_commit(struct kaudit_record *ar, int error, int retval)
454{
455 au_event_t event;
456 au_class_t class;
457 au_id_t auid;
458 int sorf;
459 struct au_mask *aumask;
460 int audit_override;
461
462 if (ar == NULL)
463 return;
464
465 /*
466 * Decide whether to commit the audit record by checking the error
467 * value from the system call and using the appropriate audit mask.
468 */
469 if (ar->k_ar.ar_subj_auid == AU_DEFAUDITID)
470 aumask = &audit_nae_mask;
471 else
472 aumask = &ar->k_ar.ar_subj_amask;
473
474 if (error)
475 sorf = AU_PRS_FAILURE;
476 else
477 sorf = AU_PRS_SUCCESS;
478
479 switch(ar->k_ar.ar_event) {
480 case AUE_OPEN_RWTC:
481 /*
482 * The open syscall always writes a AUE_OPEN_RWTC event;
483 * change it to the proper type of event based on the flags
484 * and the error value.
485 */
486 ar->k_ar.ar_event = audit_flags_and_error_to_openevent(
487 ar->k_ar.ar_arg_fflags, error);
488 break;
489
490 case AUE_OPEN_EXTENDED_RWTC:
491 /*
492 * The open_extended syscall always writes a
493 * AUE_OPEN_EXTENDEDRWTC event; change it to the proper type of
494 * event based on the flags and the error value.
495 */
496 ar->k_ar.ar_event = audit_flags_and_error_to_openextendedevent(
497 ar->k_ar.ar_arg_fflags, error);
498 break;
499
500 case AUE_OPENAT_RWTC:
501 /*
502 * The openat syscall always writes a
503 * AUE_OPENAT_RWTC event; change it to the proper type of
504 * event based on the flags and the error value.
505 */
506 ar->k_ar.ar_event = audit_flags_and_error_to_openatevent(
507 ar->k_ar.ar_arg_fflags, error);
508 break;
509
510 case AUE_OPENBYID_RWT:
511 /*
512 * The openbyid syscall always writes a
513 * AUE_OPENBYID_RWT event; change it to the proper type of
514 * event based on the flags and the error value.
515 */
516 ar->k_ar.ar_event = audit_flags_and_error_to_openbyidevent(
517 ar->k_ar.ar_arg_fflags, error);
518 break;
519
520 case AUE_SYSCTL:
521 ar->k_ar.ar_event = audit_ctlname_to_sysctlevent(
522 ar->k_ar.ar_arg_ctlname, ar->k_ar.ar_valid_arg);
523 break;
524
525 case AUE_AUDITON:
526 /* Convert the auditon() command to an event. */
527 ar->k_ar.ar_event = auditon_command_event(ar->k_ar.ar_arg_cmd);
528 break;
529
530 case AUE_FCNTL:
531 /* Convert some fcntl() commands to their own events. */
532 ar->k_ar.ar_event = audit_fcntl_command_event(
533 ar->k_ar.ar_arg_cmd, ar->k_ar.ar_arg_fflags, error);
534 break;
535 }
536
537 auid = ar->k_ar.ar_subj_auid;
538 event = ar->k_ar.ar_event;
539 class = au_event_class(event);
540
541 /*
542 * See if we need to override the audit_suspend and audit_enabled
543 * flags.
544 *
545 * XXXss - This check needs to be generalized so new filters can
546 * easily be added.
547 */
548 audit_override = (AUE_SESSION_START == event ||
549 AUE_SESSION_UPDATE == event || AUE_SESSION_END == event ||
550 AUE_SESSION_CLOSE == event);
551
552 ar->k_ar_commit |= AR_COMMIT_KERNEL;
553 if (au_preselect(event, class, aumask, sorf) != 0)
554 ar->k_ar_commit |= AR_PRESELECT_TRAIL;
555 if (audit_pipe_preselect(auid, event, class, sorf,
556 ar->k_ar_commit & AR_PRESELECT_TRAIL) != 0)
557 ar->k_ar_commit |= AR_PRESELECT_PIPE;
558 if ((ar->k_ar_commit & (AR_PRESELECT_TRAIL | AR_PRESELECT_PIPE |
559 AR_PRESELECT_USER_TRAIL | AR_PRESELECT_USER_PIPE |
560 AR_PRESELECT_FILTER)) == 0) {
561 mtx_lock(&audit_mtx);
562 audit_pre_q_len--;
563 mtx_unlock(&audit_mtx);
564 audit_free(ar);
565 return;
566 }
567
568 ar->k_ar.ar_errno = error;
569 ar->k_ar.ar_retval = retval;
570 nanotime(&ar->k_ar.ar_endtime);
571
572 /*
573 * Note: it could be that some records initiated while audit was
574 * enabled should still be committed?
575 */
576 mtx_lock(&audit_mtx);
577 if (!audit_override && (audit_suspended || !audit_enabled)) {
578 audit_pre_q_len--;
579 mtx_unlock(&audit_mtx);
580 audit_free(ar);
581 return;
582 }
583
584 /*
585 * Constrain the number of committed audit records based on the
586 * configurable parameter.
587 */
588 while (audit_q_len >= audit_qctrl.aq_hiwater)
589 cv_wait(&audit_watermark_cv, &audit_mtx);
590
591 TAILQ_INSERT_TAIL(&audit_q, ar, k_q);
592 audit_q_len++;
593 audit_pre_q_len--;
594 cv_signal(&audit_worker_cv);
595 mtx_unlock(&audit_mtx);
596}
597
598/*
599 * audit_syscall_enter() is called on entry to each system call. It is
600 * responsible for deciding whether or not to audit the call (preselection),
601 * and if so, allocating a per-thread audit record. audit_new() will fill in
602 * basic thread/credential properties.
603 */
604void
605audit_syscall_enter(unsigned int code, proc_t proc, struct uthread *uthread)
606{
607 struct au_mask *aumask;
608 au_class_t class;
609 au_event_t event;
610 au_id_t auid;
611 kauth_cred_t cred;
612
613 /*
614 * In FreeBSD, each ABI has its own system call table, and hence
615 * mapping of system call codes to audit events. Convert the code to
616 * an audit event identifier using the process system call table
617 * reference. In Darwin, there's only one, so we use the global
618 * symbol for the system call table. No audit record is generated
619 * for bad system calls, as no operation has been performed.
620 *
621 * In Mac OS X, the audit events are stored in a table seperate from
622 * the syscall table(s). This table is generated by makesyscalls.sh
623 * from syscalls.master and stored in audit_kevents.c.
624 */
625 if (code >= nsysent)
626 return;
627 event = sys_au_event[code];
628 if (event == AUE_NULL)
629 return;
630
631 KASSERT(uthread->uu_ar == NULL,
632 ("audit_syscall_enter: uthread->uu_ar != NULL"));
633
634 /*
635 * Check which audit mask to use; either the kernel non-attributable
636 * event mask or the process audit mask.
637 */
638 cred = kauth_cred_proc_ref(proc);
639 auid = cred->cr_audit.as_aia_p->ai_auid;
640 if (auid == AU_DEFAUDITID)
641 aumask = &audit_nae_mask;
642 else
643 aumask = &cred->cr_audit.as_mask;
644
645 /*
646 * Allocate an audit record, if preselection allows it, and store in
647 * the thread for later use.
648 */
649 class = au_event_class(event);
650#if CONFIG_MACF
651 /*
652 * Note: audit_mac_syscall_enter() may call audit_new() and allocate
653 * memory for the audit record (uu_ar).
654 */
655 if (audit_mac_syscall_enter(code, proc, uthread, cred, event) == 0)
656 goto out;
657#endif
658 if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
659 /*
660 * If we're out of space and need to suspend unprivileged
661 * processes, do that here rather than trying to allocate
662 * another audit record.
663 *
664 * Note: we might wish to be able to continue here in the
665 * future, if the system recovers. That should be possible
666 * by means of checking the condition in a loop around
667 * cv_wait(). It might be desirable to reevaluate whether an
668 * audit record is still required for this event by
669 * re-calling au_preselect().
670 */
671 if (audit_in_failure &&
672 suser(cred, &proc->p_acflag) != 0) {
673 cv_wait(&audit_fail_cv, &audit_mtx);
674 panic("audit_failing_stop: thread continued");
675 }
676 if (uthread->uu_ar == NULL)
677 uthread->uu_ar = audit_new(event, proc, uthread);
678 } else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
679 if (uthread->uu_ar == NULL)
680 uthread->uu_ar = audit_new(event, proc, uthread);
681 }
682
683 /*
684 * All audited events will contain an identity
685 *
686 * Note: Identity should be obtained prior to the syscall implementation
687 * being called to handle cases like execve(2) where the process changes
688 */
689 AUDIT_ARG(identity);
690
691out:
692 kauth_cred_unref(&cred);
693}
694
695/*
696 * audit_syscall_exit() is called from the return of every system call, or in
697 * the event of exit1(), during the execution of exit1(). It is responsible
698 * for committing the audit record, if any, along with return condition.
699 *
700 * Note: The audit_syscall_exit() parameter list was modified to support
701 * mac_audit_check_postselect(), which requires the syscall number.
702 */
703#if CONFIG_MACF
704void
705audit_syscall_exit(unsigned int code, int error, __unused proc_t proc,
706 struct uthread *uthread)
707#else
708void
709audit_syscall_exit(int error, __unsed proc_t proc, struct uthread *uthread)
710#endif
711{
712 int retval;
713
714 /*
715 * Commit the audit record as desired; once we pass the record into
716 * audit_commit(), the memory is owned by the audit subsystem. The
717 * return value from the system call is stored on the user thread.
718 * If there was an error, the return value is set to -1, imitating
719 * the behavior of the cerror routine.
720 */
721 if (error)
722 retval = -1;
723 else
724 retval = uthread->uu_rval[0];
725
726#if CONFIG_MACF
727 if (audit_mac_syscall_exit(code, uthread, error, retval) != 0)
728 goto out;
729#endif
730 audit_commit(uthread->uu_ar, error, retval);
731
732out:
733 uthread->uu_ar = NULL;
734}
735
736/*
737 * Calls to set up and tear down audit structures used during Mach system
738 * calls.
739 */
740void
741audit_mach_syscall_enter(unsigned short event)
742{
743 struct uthread *uthread;
744 proc_t proc;
745 struct au_mask *aumask;
746 kauth_cred_t cred;
747 au_class_t class;
748 au_id_t auid;
749
750 if (event == AUE_NULL)
751 return;
752
753 uthread = curthread();
754 if (uthread == NULL)
755 return;
756
757 proc = current_proc();
758 if (proc == NULL)
759 return;
760
761 KASSERT(uthread->uu_ar == NULL,
762 ("audit_mach_syscall_enter: uthread->uu_ar != NULL"));
763
764 cred = kauth_cred_proc_ref(proc);
765 auid = cred->cr_audit.as_aia_p->ai_auid;
766
767 /*
768 * Check which audit mask to use; either the kernel non-attributable
769 * event mask or the process audit mask.
770 */
771 if (auid == AU_DEFAUDITID)
772 aumask = &audit_nae_mask;
773 else
774 aumask = &cred->cr_audit.as_mask;
775
776 /*
777 * Allocate an audit record, if desired, and store in the BSD thread
778 * for later use.
779 */
780 class = au_event_class(event);
781 if (au_preselect(event, class, aumask, AU_PRS_BOTH))
782 uthread->uu_ar = audit_new(event, proc, uthread);
783 else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0))
784 uthread->uu_ar = audit_new(event, proc, uthread);
785 else
786 uthread->uu_ar = NULL;
787
788 kauth_cred_unref(&cred);
789}
790
791void
792audit_mach_syscall_exit(int retval, struct uthread *uthread)
793{
794 /*
795 * The error code from Mach system calls is the same as the
796 * return value
797 */
798 /* XXX Is the above statement always true? */
799 audit_commit(uthread->uu_ar, retval, retval);
800 uthread->uu_ar = NULL;
801}
802
803/*
804 * kau_will_audit can be used by a security policy to determine
805 * if an audit record will be stored, reducing wasted memory allocation
806 * and string handling.
807 */
808int
809kau_will_audit(void)
810{
811
812 return (audit_enabled && currecord() != NULL);
813}
814
815#if CONFIG_COREDUMP
816void
817audit_proc_coredump(proc_t proc, char *path, int errcode)
818{
819 struct kaudit_record *ar;
820 struct au_mask *aumask;
821 au_class_t class;
822 int ret, sorf;
823 char **pathp;
824 au_id_t auid;
825 kauth_cred_t my_cred;
826 struct uthread *uthread;
827
828 ret = 0;
829
830 /*
831 * Make sure we are using the correct preselection mask.
832 */
833 my_cred = kauth_cred_proc_ref(proc);
834 auid = my_cred->cr_audit.as_aia_p->ai_auid;
835 if (auid == AU_DEFAUDITID)
836 aumask = &audit_nae_mask;
837 else
838 aumask = &my_cred->cr_audit.as_mask;
839 kauth_cred_unref(&my_cred);
840 /*
841 * It's possible for coredump(9) generation to fail. Make sure that
842 * we handle this case correctly for preselection.
843 */
844 if (errcode != 0)
845 sorf = AU_PRS_FAILURE;
846 else
847 sorf = AU_PRS_SUCCESS;
848 class = au_event_class(AUE_CORE);
849 if (au_preselect(AUE_CORE, class, aumask, sorf) == 0 &&
850 audit_pipe_preselect(auid, AUE_CORE, class, sorf, 0) == 0)
851 return;
852 /*
853 * If we are interested in seeing this audit record, allocate it.
854 * Where possible coredump records should contain a pathname and arg32
855 * (signal) tokens.
856 */
857 uthread = curthread();
858 ar = audit_new(AUE_CORE, proc, uthread);
859 if (path != NULL) {
860 pathp = &ar->k_ar.ar_arg_upath1;
861 *pathp = malloc(MAXPATHLEN, M_AUDITPATH, M_WAITOK);
862 if (audit_canon_path(vfs_context_cwd(vfs_context_current()), path,
863 *pathp))
864 free(*pathp, M_AUDITPATH);
865 else
866 ARG_SET_VALID(ar, ARG_UPATH1);
867 }
868 ar->k_ar.ar_arg_signum = proc->p_sigacts->ps_sig;
869 ARG_SET_VALID(ar, ARG_SIGNUM);
870 if (errcode != 0)
871 ret = 1;
872 audit_commit(ar, errcode, ret);
873}
874#endif /* CONFIG_COREDUMP */
875#endif /* CONFIG_AUDIT */
876