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/wait_queue.h>
80#include <kern/sched_prim.h>
81
82#include <net/route.h>
83
84#include <netinet/in.h>
85#include <netinet/in_pcb.h>
86
87#if CONFIG_AUDIT
88MALLOC_DEFINE(M_AUDITDATA, "audit_data", "Audit data storage");
89MALLOC_DEFINE(M_AUDITPATH, "audit_path", "Audit path storage");
90MALLOC_DEFINE(M_AUDITTEXT, "audit_text", "Audit text storage");
91
92/*
93 * Audit control settings that are set/read by system calls and are hence
94 * non-static.
95 *
96 * Define the audit control flags.
97 */
98int			audit_enabled;
99int			audit_suspended;
100
101int			audit_syscalls;
102au_class_t 		audit_kevent_mask;
103
104/*
105 * Flags controlling behavior in low storage situations.  Should we panic if
106 * a write fails?  Should we fail stop if we're out of disk space?
107 */
108int			audit_panic_on_write_fail;
109int			audit_fail_stop;
110int			audit_argv;
111int			audit_arge;
112
113/*
114 * Are we currently "failing stop" due to out of disk space?
115 */
116int			audit_in_failure;
117
118/*
119 * Global audit statistics.
120 */
121struct audit_fstat	audit_fstat;
122
123/*
124 * Preselection mask for non-attributable events.
125 */
126struct au_mask		audit_nae_mask;
127
128/*
129 * Mutex to protect global variables shared between various threads and
130 * processes.
131 */
132struct mtx		audit_mtx;
133
134/*
135 * Queue of audit records ready for delivery to disk.  We insert new records
136 * at the tail, and remove records from the head.  Also, a count of the
137 * number of records used for checking queue depth.  In addition, a counter
138 * of records that we have allocated but are not yet in the queue, which is
139 * needed to estimate the total size of the combined set of records
140 * outstanding in the system.
141 */
142struct kaudit_queue	audit_q;
143int			audit_q_len;
144int			audit_pre_q_len;
145
146/*
147 * Audit queue control settings (minimum free, low/high water marks, etc.)
148 */
149struct au_qctrl		audit_qctrl;
150
151/*
152 * Condition variable to signal to the worker that it has work to do: either
153 * new records are in the queue, or a log replacement is taking place.
154 */
155struct cv		audit_worker_cv;
156
157/*
158 * Condition variable to signal when the worker is done draining the audit
159 * queue.
160 */
161struct cv		audit_drain_cv;
162
163/*
164 * Condition variable to flag when crossing the low watermark, meaning that
165 * threads blocked due to hitting the high watermark can wake up and continue
166 * to commit records.
167 */
168struct cv		audit_watermark_cv;
169
170/*
171 * Condition variable for  auditing threads wait on when in fail-stop mode.
172 * Threads wait on this CV forever (and ever), never seeing the light of day
173 * again.
174 */
175static struct cv	audit_fail_cv;
176
177static zone_t		audit_record_zone;
178
179/*
180 * Kernel audit information.  This will store the current audit address
181 * or host information that the kernel will use when it's generating
182 * audit records.  This data is modified by the A_GET{SET}KAUDIT auditon(2)
183 * command.
184 */
185static struct auditinfo_addr	audit_kinfo;
186static struct rwlock		audit_kinfo_lock;
187
188#define	KINFO_LOCK_INIT()	rw_init(&audit_kinfo_lock,		\
189					"audit_kinfo_lock")
190#define	KINFO_RLOCK()		rw_rlock(&audit_kinfo_lock)
191#define KINFO_WLOCK()		rw_wlock(&audit_kinfo_lock)
192#define	KINFO_RUNLOCK()		rw_runlock(&audit_kinfo_lock)
193#define	KINFO_WUNLOCK()		rw_wunlock(&audit_kinfo_lock)
194
195void
196audit_set_kinfo(struct auditinfo_addr *ak)
197{
198
199	KASSERT(ak->ai_termid.at_type == AU_IPv4 ||
200	    ak->ai_termid.at_type == AU_IPv6,
201	    ("audit_set_kinfo: invalid address type"));
202
203	KINFO_WLOCK();
204	bcopy(ak, &audit_kinfo, sizeof(audit_kinfo));
205	KINFO_WUNLOCK();
206}
207
208void
209audit_get_kinfo(struct auditinfo_addr *ak)
210{
211
212	KASSERT(audit_kinfo.ai_termid.at_type == AU_IPv4 ||
213	    audit_kinfo.ai_termid.at_type == AU_IPv6,
214	    ("audit_set_kinfo: invalid address type"));
215
216	KINFO_RLOCK();
217	bcopy(&audit_kinfo, ak, sizeof(*ak));
218	KINFO_RUNLOCK();
219}
220
221/*
222 * Construct an audit record for the passed thread.
223 */
224static void
225audit_record_ctor(proc_t p, struct kaudit_record *ar)
226{
227	kauth_cred_t cred;
228
229	bzero(ar, sizeof(*ar));
230	ar->k_ar.ar_magic = AUDIT_RECORD_MAGIC;
231	nanotime(&ar->k_ar.ar_starttime);
232
233	if (PROC_NULL != p) {
234		cred = kauth_cred_proc_ref(p);
235
236		/*
237	 	 * Export the subject credential.
238	 	 */
239		cru2x(cred, &ar->k_ar.ar_subj_cred);
240		ar->k_ar.ar_subj_ruid = kauth_cred_getruid(cred);
241		ar->k_ar.ar_subj_rgid = kauth_cred_getrgid(cred);
242		ar->k_ar.ar_subj_egid = kauth_cred_getgid(cred);
243		ar->k_ar.ar_subj_pid = p->p_pid;
244		ar->k_ar.ar_subj_auid = cred->cr_audit.as_aia_p->ai_auid;
245		ar->k_ar.ar_subj_asid = cred->cr_audit.as_aia_p->ai_asid;
246		bcopy(&cred->cr_audit.as_mask, &ar->k_ar.ar_subj_amask,
247    		    sizeof(struct au_mask));
248		bcopy(&cred->cr_audit.as_aia_p->ai_termid,
249		    &ar->k_ar.ar_subj_term_addr, sizeof(struct au_tid_addr));
250		kauth_cred_unref(&cred);
251	}
252}
253
254static void
255audit_record_dtor(struct kaudit_record *ar)
256{
257
258	if (ar->k_ar.ar_arg_upath1 != NULL)
259		free(ar->k_ar.ar_arg_upath1, M_AUDITPATH);
260	if (ar->k_ar.ar_arg_upath2 != NULL)
261		free(ar->k_ar.ar_arg_upath2, M_AUDITPATH);
262	if (ar->k_ar.ar_arg_kpath1 != NULL)
263		free(ar->k_ar.ar_arg_kpath1, M_AUDITPATH);
264	if (ar->k_ar.ar_arg_kpath2 != NULL)
265		free(ar->k_ar.ar_arg_kpath2, M_AUDITPATH);
266	if (ar->k_ar.ar_arg_text != NULL)
267		free(ar->k_ar.ar_arg_text, M_AUDITTEXT);
268	if (ar->k_ar.ar_arg_opaque != NULL)
269		free(ar->k_ar.ar_arg_opaque, M_AUDITDATA);
270	if (ar->k_ar.ar_arg_data != NULL)
271		free(ar->k_ar.ar_arg_data, M_AUDITDATA);
272	if (ar->k_udata != NULL)
273		free(ar->k_udata, M_AUDITDATA);
274	if (ar->k_ar.ar_arg_argv != NULL)
275		free(ar->k_ar.ar_arg_argv, M_AUDITTEXT);
276	if (ar->k_ar.ar_arg_envv != NULL)
277		free(ar->k_ar.ar_arg_envv, M_AUDITTEXT);
278}
279
280/*
281 * Initialize the Audit subsystem: configuration state, work queue,
282 * synchronization primitives, worker thread, and trigger device node.  Also
283 * call into the BSM assembly code to initialize it.
284 */
285void
286audit_init(void)
287{
288
289	audit_enabled = 0;
290	audit_syscalls = 0;
291	audit_kevent_mask = 0;
292	audit_suspended = 0;
293	audit_panic_on_write_fail = 0;
294	audit_fail_stop = 0;
295	audit_in_failure = 0;
296	audit_argv = 0;
297	audit_arge = 0;
298
299	audit_fstat.af_filesz = 0;	/* '0' means unset, unbounded. */
300	audit_fstat.af_currsz = 0;
301	audit_nae_mask.am_success = 0;
302	audit_nae_mask.am_failure = 0;
303
304	TAILQ_INIT(&audit_q);
305	audit_q_len = 0;
306	audit_pre_q_len = 0;
307	audit_qctrl.aq_hiwater = AQ_HIWATER;
308	audit_qctrl.aq_lowater = AQ_LOWATER;
309	audit_qctrl.aq_bufsz = AQ_BUFSZ;
310	audit_qctrl.aq_minfree = AU_FS_MINFREE;
311
312	audit_kinfo.ai_termid.at_type = AU_IPv4;
313	audit_kinfo.ai_termid.at_addr[0] = INADDR_ANY;
314
315	_audit_lck_grp_init();
316	mtx_init(&audit_mtx, "audit_mtx", NULL, MTX_DEF);
317	KINFO_LOCK_INIT();
318	cv_init(&audit_worker_cv, "audit_worker_cv");
319	cv_init(&audit_drain_cv, "audit_drain_cv");
320	cv_init(&audit_watermark_cv, "audit_watermark_cv");
321	cv_init(&audit_fail_cv, "audit_fail_cv");
322
323	audit_record_zone = zinit(sizeof(struct kaudit_record),
324	    AQ_HIWATER*sizeof(struct kaudit_record), 8192, "audit_zone");
325#if CONFIG_MACF
326	audit_mac_init();
327#endif
328	/* Init audit session subsystem. */
329	audit_session_init();
330
331	/* Initialize the BSM audit subsystem. */
332	kau_init();
333
334	/* audit_trigger_init(); */
335
336	/* Start audit worker thread. */
337	(void) audit_pipe_init();
338
339	/* Start audit worker thread. */
340	audit_worker_init();
341}
342
343/*
344 * Drain the audit queue and close the log at shutdown.  Note that this can
345 * be called both from the system shutdown path and also from audit
346 * configuration syscalls, so 'arg' and 'howto' are ignored.
347 */
348void
349audit_shutdown(void)
350{
351
352	audit_rotate_vnode(NULL, NULL);
353}
354
355/*
356 * Return the current thread's audit record, if any.
357 */
358struct kaudit_record *
359currecord(void)
360{
361
362	return (curthread()->uu_ar);
363}
364
365/*
366 * XXXAUDIT: There are a number of races present in the code below due to
367 * release and re-grab of the mutex.  The code should be revised to become
368 * slightly less racy.
369 *
370 * XXXAUDIT: Shouldn't there be logic here to sleep waiting on available
371 * pre_q space, suspending the system call until there is room?
372 */
373struct kaudit_record *
374audit_new(int event, proc_t p, __unused struct uthread *uthread)
375{
376	struct kaudit_record *ar;
377	int no_record;
378	int audit_override;
379
380	/*
381	 * Override the audit_suspended and audit_enabled if it always
382	 * audits session events.
383	 *
384	 * XXXss - This really needs to be a generalized call to a filter
385	 * interface so if other things that use the audit subsystem in the
386	 * future can simply plugged in.
387	 */
388	audit_override = (AUE_SESSION_START == event ||
389	    AUE_SESSION_UPDATE == event || AUE_SESSION_END == event ||
390	    AUE_SESSION_CLOSE == event);
391
392	mtx_lock(&audit_mtx);
393	no_record = (audit_suspended || !audit_enabled);
394	mtx_unlock(&audit_mtx);
395	if (!audit_override && no_record)
396		return (NULL);
397
398	/*
399	 * Initialize the audit record header.
400	 * XXX: We may want to fail-stop if allocation fails.
401	 *
402	 * Note: the number of outstanding uncommitted audit records is
403	 * limited to the number of concurrent threads servicing system calls
404	 * in the kernel.
405	 */
406	ar = zalloc(audit_record_zone);
407	if (ar == NULL)
408		return NULL;
409	audit_record_ctor(p, ar);
410	ar->k_ar.ar_event = event;
411
412#if CONFIG_MACF
413	if (PROC_NULL != p) {
414		if (audit_mac_new(p, ar) != 0) {
415			zfree(audit_record_zone, ar);
416			return (NULL);
417		}
418	} else
419		ar->k_ar.ar_mac_records = NULL;
420#endif
421
422	mtx_lock(&audit_mtx);
423	audit_pre_q_len++;
424	mtx_unlock(&audit_mtx);
425
426	return (ar);
427}
428
429void
430audit_free(struct kaudit_record *ar)
431{
432
433	audit_record_dtor(ar);
434#if CONFIG_MACF
435	if (NULL != ar->k_ar.ar_mac_records)
436		audit_mac_free(ar);
437#endif
438	zfree(audit_record_zone, ar);
439}
440
441void
442audit_commit(struct kaudit_record *ar, int error, int retval)
443{
444	au_event_t event;
445	au_class_t class;
446	au_id_t auid;
447	int sorf;
448	struct au_mask *aumask;
449	int audit_override;
450
451	if (ar == NULL)
452		return;
453
454	/*
455	 * Decide whether to commit the audit record by checking the error
456	 * value from the system call and using the appropriate audit mask.
457	 */
458	if (ar->k_ar.ar_subj_auid == AU_DEFAUDITID)
459		aumask = &audit_nae_mask;
460	else
461		aumask = &ar->k_ar.ar_subj_amask;
462
463	if (error)
464		sorf = AU_PRS_FAILURE;
465	else
466		sorf = AU_PRS_SUCCESS;
467
468	switch(ar->k_ar.ar_event) {
469	case AUE_OPEN_RWTC:
470		/*
471		 * The open syscall always writes a AUE_OPEN_RWTC event;
472		 * change it to the proper type of event based on the flags
473		 * and the error value.
474		 */
475		ar->k_ar.ar_event = audit_flags_and_error_to_openevent(
476		    ar->k_ar.ar_arg_fflags, error);
477		break;
478
479	case AUE_OPEN_EXTENDED_RWTC:
480		/*
481		 * The open_extended syscall always writes a
482		 * AUE_OPEN_EXTENDEDRWTC event; change it to the proper type of
483		 * event based on the flags and the error value.
484		 */
485		ar->k_ar.ar_event = audit_flags_and_error_to_openextendedevent(
486		    ar->k_ar.ar_arg_fflags, error);
487		break;
488
489	case AUE_OPENAT_RWTC:
490		/*
491		 * The openat syscall always writes a
492		 * AUE_OPENAT_RWTC event; change it to the proper type of
493		 * event based on the flags and the error value.
494		 */
495		ar->k_ar.ar_event = audit_flags_and_error_to_openatevent(
496		    ar->k_ar.ar_arg_fflags, error);
497		break;
498
499	case AUE_OPENBYID_RWT:
500		/*
501		 * The openbyid syscall always writes a
502		 * AUE_OPENBYID_RWT event; change it to the proper type of
503		 * event based on the flags and the error value.
504		 */
505		ar->k_ar.ar_event = audit_flags_and_error_to_openbyidevent(
506		    ar->k_ar.ar_arg_fflags, error);
507		break;
508
509	case AUE_SYSCTL:
510		ar->k_ar.ar_event = audit_ctlname_to_sysctlevent(
511		    ar->k_ar.ar_arg_ctlname, ar->k_ar.ar_valid_arg);
512		break;
513
514	case AUE_AUDITON:
515		/* Convert the auditon() command to an event. */
516		ar->k_ar.ar_event = auditon_command_event(ar->k_ar.ar_arg_cmd);
517		break;
518
519	case AUE_FCNTL:
520		/* Convert some fcntl() commands to their own events. */
521		ar->k_ar.ar_event = audit_fcntl_command_event(
522		    ar->k_ar.ar_arg_cmd, ar->k_ar.ar_arg_fflags, error);
523		break;
524	}
525
526	auid = ar->k_ar.ar_subj_auid;
527	event = ar->k_ar.ar_event;
528	class = au_event_class(event);
529
530	/*
531	 * See if we need to override the audit_suspend and audit_enabled
532	 * flags.
533	 *
534	 * XXXss - This check needs to be generalized so new filters can
535	 * easily be added.
536	 */
537	audit_override = (AUE_SESSION_START == event ||
538	    AUE_SESSION_UPDATE == event || AUE_SESSION_END == event ||
539	    AUE_SESSION_CLOSE == event);
540
541	ar->k_ar_commit |= AR_COMMIT_KERNEL;
542	if (au_preselect(event, class, aumask, sorf) != 0)
543		ar->k_ar_commit |= AR_PRESELECT_TRAIL;
544	if (audit_pipe_preselect(auid, event, class, sorf,
545	    ar->k_ar_commit & AR_PRESELECT_TRAIL) != 0)
546		ar->k_ar_commit |= AR_PRESELECT_PIPE;
547	if ((ar->k_ar_commit & (AR_PRESELECT_TRAIL | AR_PRESELECT_PIPE |
548	    AR_PRESELECT_USER_TRAIL | AR_PRESELECT_USER_PIPE |
549	    AR_PRESELECT_FILTER)) == 0) {
550		mtx_lock(&audit_mtx);
551		audit_pre_q_len--;
552		mtx_unlock(&audit_mtx);
553		audit_free(ar);
554		return;
555	}
556
557	ar->k_ar.ar_errno = error;
558	ar->k_ar.ar_retval = retval;
559	nanotime(&ar->k_ar.ar_endtime);
560
561	/*
562	 * Note: it could be that some records initiated while audit was
563	 * enabled should still be committed?
564	 */
565	mtx_lock(&audit_mtx);
566	if (!audit_override && (audit_suspended || !audit_enabled)) {
567		audit_pre_q_len--;
568		mtx_unlock(&audit_mtx);
569		audit_free(ar);
570		return;
571	}
572
573	/*
574	 * Constrain the number of committed audit records based on the
575	 * configurable parameter.
576	 */
577	while (audit_q_len >= audit_qctrl.aq_hiwater)
578		cv_wait(&audit_watermark_cv, &audit_mtx);
579
580	TAILQ_INSERT_TAIL(&audit_q, ar, k_q);
581	audit_q_len++;
582	audit_pre_q_len--;
583	cv_signal(&audit_worker_cv);
584	mtx_unlock(&audit_mtx);
585}
586
587/*
588 * audit_syscall_enter() is called on entry to each system call.  It is
589 * responsible for deciding whether or not to audit the call (preselection),
590 * and if so, allocating a per-thread audit record.  audit_new() will fill in
591 * basic thread/credential properties.
592 */
593void
594audit_syscall_enter(unsigned int code, proc_t proc, struct uthread *uthread)
595{
596	struct au_mask *aumask;
597	au_class_t class;
598	au_event_t event;
599	au_id_t auid;
600	kauth_cred_t cred;
601
602	/*
603	 * In FreeBSD, each ABI has its own system call table, and hence
604	 * mapping of system call codes to audit events.  Convert the code to
605	 * an audit event identifier using the process system call table
606	 * reference.  In Darwin, there's only one, so we use the global
607	 * symbol for the system call table.  No audit record is generated
608	 * for bad system calls, as no operation has been performed.
609	 *
610	 * In Mac OS X, the audit events are stored in a table seperate from
611	 * the syscall table(s).  This table is generated by makesyscalls.sh
612	 * from syscalls.master and stored in audit_kevents.c.
613	 */
614	if (code > NUM_SYSENT)
615		return;
616	event = sys_au_event[code];
617	if (event == AUE_NULL)
618		return;
619
620	KASSERT(uthread->uu_ar == NULL,
621	    ("audit_syscall_enter: uthread->uu_ar != NULL"));
622
623	/*
624	 * Check which audit mask to use; either the kernel non-attributable
625	 * event mask or the process audit mask.
626	 */
627	cred = kauth_cred_proc_ref(proc);
628	auid = cred->cr_audit.as_aia_p->ai_auid;
629	if (auid == AU_DEFAUDITID)
630		aumask = &audit_nae_mask;
631	else
632		aumask = &cred->cr_audit.as_mask;
633
634	/*
635	 * Allocate an audit record, if preselection allows it, and store in
636	 * the thread for later use.
637	 */
638	class = au_event_class(event);
639#if CONFIG_MACF
640	/*
641	 * Note: audit_mac_syscall_enter() may call audit_new() and allocate
642	 * memory for the audit record (uu_ar).
643	 */
644	if (audit_mac_syscall_enter(code, proc, uthread, cred, event) == 0)
645		goto out;
646#endif
647	if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
648		/*
649		 * If we're out of space and need to suspend unprivileged
650		 * processes, do that here rather than trying to allocate
651		 * another audit record.
652		 *
653		 * Note: we might wish to be able to continue here in the
654		 * future, if the system recovers.  That should be possible
655		 * by means of checking the condition in a loop around
656		 * cv_wait().  It might be desirable to reevaluate whether an
657		 * audit record is still required for this event by
658		 * re-calling au_preselect().
659		 */
660		if (audit_in_failure &&
661		    suser(cred, &proc->p_acflag) != 0) {
662			cv_wait(&audit_fail_cv, &audit_mtx);
663			panic("audit_failing_stop: thread continued");
664		}
665		if (uthread->uu_ar == NULL)
666			uthread->uu_ar = audit_new(event, proc, uthread);
667	} else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
668		if (uthread->uu_ar == NULL)
669			uthread->uu_ar = audit_new(event, proc, uthread);
670	}
671
672out:
673	kauth_cred_unref(&cred);
674}
675
676/*
677 * audit_syscall_exit() is called from the return of every system call, or in
678 * the event of exit1(), during the execution of exit1().  It is responsible
679 * for committing the audit record, if any, along with return condition.
680 *
681 * Note: The audit_syscall_exit() parameter list was modified to support
682 * mac_audit_check_postselect(), which requires the syscall number.
683 */
684#if CONFIG_MACF
685void
686audit_syscall_exit(unsigned int code, int error, __unused proc_t proc,
687    struct uthread *uthread)
688#else
689void
690audit_syscall_exit(int error, __unsed proc_t proc, struct uthread *uthread)
691#endif
692{
693	int retval;
694
695	/*
696	 * Commit the audit record as desired; once we pass the record into
697	 * audit_commit(), the memory is owned by the audit subsystem.  The
698	 * return value from the system call is stored on the user thread.
699	 * If there was an error, the return value is set to -1, imitating
700	 * the behavior of the cerror routine.
701	 */
702	if (error)
703		retval = -1;
704	else
705		retval = uthread->uu_rval[0];
706
707#if CONFIG_MACF
708	if (audit_mac_syscall_exit(code, uthread, error, retval) != 0)
709		goto out;
710#endif
711	audit_commit(uthread->uu_ar, error, retval);
712
713out:
714	uthread->uu_ar = NULL;
715}
716
717/*
718 * Calls to set up and tear down audit structures used during Mach system
719 * calls.
720 */
721void
722audit_mach_syscall_enter(unsigned short event)
723{
724	struct uthread *uthread;
725	proc_t proc;
726	struct au_mask *aumask;
727	kauth_cred_t cred;
728	au_class_t class;
729	au_id_t auid;
730
731	if (event == AUE_NULL)
732		return;
733
734	uthread = curthread();
735	if (uthread == NULL)
736		return;
737
738	proc = current_proc();
739	if (proc == NULL)
740		return;
741
742	KASSERT(uthread->uu_ar == NULL,
743	    ("audit_mach_syscall_enter: uthread->uu_ar != NULL"));
744
745	cred = kauth_cred_proc_ref(proc);
746	auid = cred->cr_audit.as_aia_p->ai_auid;
747
748	/*
749	 * Check which audit mask to use; either the kernel non-attributable
750	 * event mask or the process audit mask.
751	 */
752	if (auid == AU_DEFAUDITID)
753		aumask = &audit_nae_mask;
754	else
755		aumask = &cred->cr_audit.as_mask;
756
757	/*
758	 * Allocate an audit record, if desired, and store in the BSD thread
759	 * for later use.
760	 */
761	class = au_event_class(event);
762	if (au_preselect(event, class, aumask, AU_PRS_BOTH))
763		uthread->uu_ar = audit_new(event, proc, uthread);
764	else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0))
765		uthread->uu_ar = audit_new(event, proc, uthread);
766	else
767		uthread->uu_ar = NULL;
768
769	kauth_cred_unref(&cred);
770}
771
772void
773audit_mach_syscall_exit(int retval, struct uthread *uthread)
774{
775	/*
776	 * The error code from Mach system calls is the same as the
777	 * return value
778	 */
779	/* XXX Is the above statement always true? */
780	audit_commit(uthread->uu_ar, retval, retval);
781	uthread->uu_ar = NULL;
782}
783
784/*
785 * kau_will_audit can be used by a security policy to determine
786 * if an audit record will be stored, reducing wasted memory allocation
787 * and string handling.
788 */
789int
790kau_will_audit(void)
791{
792
793	return (audit_enabled && currecord() != NULL);
794}
795
796void
797audit_proc_coredump(proc_t proc, char *path, int errcode)
798{
799	struct kaudit_record *ar;
800	struct au_mask *aumask;
801	au_class_t class;
802	int ret, sorf;
803	char **pathp;
804	au_id_t auid;
805	kauth_cred_t my_cred;
806	struct uthread *uthread;
807
808	ret = 0;
809
810	/*
811	 * Make sure we are using the correct preselection mask.
812	 */
813	my_cred = kauth_cred_proc_ref(proc);
814	auid = my_cred->cr_audit.as_aia_p->ai_auid;
815	if (auid == AU_DEFAUDITID)
816		aumask = &audit_nae_mask;
817	else
818		aumask = &my_cred->cr_audit.as_mask;
819	kauth_cred_unref(&my_cred);
820	/*
821	 * It's possible for coredump(9) generation to fail.  Make sure that
822	 * we handle this case correctly for preselection.
823	 */
824	if (errcode != 0)
825		sorf = AU_PRS_FAILURE;
826	else
827		sorf = AU_PRS_SUCCESS;
828	class = au_event_class(AUE_CORE);
829	if (au_preselect(AUE_CORE, class, aumask, sorf) == 0 &&
830	    audit_pipe_preselect(auid, AUE_CORE, class, sorf, 0) == 0)
831		return;
832	/*
833	 * If we are interested in seeing this audit record, allocate it.
834	 * Where possible coredump records should contain a pathname and arg32
835	 * (signal) tokens.
836	 */
837	uthread = curthread();
838	ar = audit_new(AUE_CORE, proc, uthread);
839	if (path != NULL) {
840		pathp = &ar->k_ar.ar_arg_upath1;
841		*pathp = malloc(MAXPATHLEN, M_AUDITPATH, M_WAITOK);
842		if (audit_canon_path(vfs_context_cwd(vfs_context_current()), path,
843		    *pathp))
844			free(*pathp, M_AUDITPATH);
845		else
846			ARG_SET_VALID(ar, ARG_UPATH1);
847	}
848	ar->k_ar.ar_arg_signum = proc->p_sigacts->ps_sig;
849	ARG_SET_VALID(ar, ARG_SIGNUM);
850	if (errcode != 0)
851		ret = 1;
852	audit_commit(ar, errcode, ret);
853}
854#endif /* CONFIG_AUDIT */
855