1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1999-2005 Apple Inc.
5 * Copyright (c) 2006-2007, 2016-2018 Robert N. M. Watson
6 * All rights reserved.
7 *
8 * Portions of this software were developed by BAE Systems, the University of
9 * Cambridge Computer Laboratory, and Memorial University under DARPA/AFRL
10 * contract FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent
11 * Computing (TC) research program.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. Neither the name of Apple Inc. ("Apple") nor the names of
22 * its contributors may be used to endorse or promote products derived
23 * from this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR
29 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
33 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
34 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38 #include <sys/param.h>
39 #include <sys/condvar.h>
40 #include <sys/conf.h>
41 #include <sys/eventhandler.h>
42 #include <sys/file.h>
43 #include <sys/filedesc.h>
44 #include <sys/fcntl.h>
45 #include <sys/ipc.h>
46 #include <sys/jail.h>
47 #include <sys/kernel.h>
48 #include <sys/kthread.h>
49 #include <sys/malloc.h>
50 #include <sys/mount.h>
51 #include <sys/namei.h>
52 #include <sys/priv.h>
53 #include <sys/proc.h>
54 #include <sys/queue.h>
55 #include <sys/socket.h>
56 #include <sys/socketvar.h>
57 #include <sys/protosw.h>
58 #include <sys/domain.h>
59 #include <sys/sysctl.h>
60 #include <sys/sysproto.h>
61 #include <sys/sysent.h>
62 #include <sys/systm.h>
63 #include <sys/ucred.h>
64 #include <sys/uio.h>
65 #include <sys/un.h>
66 #include <sys/unistd.h>
67 #include <sys/vnode.h>
68
69 #include <bsm/audit.h>
70 #include <bsm/audit_internal.h>
71 #include <bsm/audit_kevents.h>
72
73 #include <netinet/in.h>
74 #include <netinet/in_pcb.h>
75
76 #include <security/audit/audit.h>
77 #include <security/audit/audit_private.h>
78
79 #include <vm/uma.h>
80
81 FEATURE(audit, "BSM audit support");
82
83 static uma_zone_t audit_record_zone;
84 static MALLOC_DEFINE(M_AUDITCRED, "audit_cred", "Audit cred storage");
85 MALLOC_DEFINE(M_AUDITDATA, "audit_data", "Audit data storage");
86 MALLOC_DEFINE(M_AUDITPATH, "audit_path", "Audit path storage");
87 MALLOC_DEFINE(M_AUDITTEXT, "audit_text", "Audit text storage");
88 MALLOC_DEFINE(M_AUDITGIDSET, "audit_gidset", "Audit GID set storage");
89
90 static SYSCTL_NODE(_security, OID_AUTO, audit, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
91 "TrustedBSD audit controls");
92
93 /*
94 * Audit control settings that are set/read by system calls and are hence
95 * non-static.
96 *
97 * Define the audit control flags.
98 */
99 int audit_trail_enabled;
100 int audit_trail_suspended;
101 #ifdef KDTRACE_HOOKS
102 u_int audit_dtrace_enabled;
103 #endif
104 bool __read_frequently audit_syscalls_enabled;
105
106 /*
107 * Flags controlling behavior in low storage situations. Should we panic if
108 * a write fails? Should we fail stop if we're out of disk space?
109 */
110 int audit_panic_on_write_fail;
111 int audit_fail_stop;
112 int audit_argv;
113 int audit_arge;
114
115 /*
116 * Are we currently "failing stop" due to out of disk space?
117 */
118 int audit_in_failure;
119
120 /*
121 * Global audit statistics.
122 */
123 struct audit_fstat audit_fstat;
124
125 /*
126 * Preselection mask for non-attributable events.
127 */
128 struct au_mask audit_nae_mask;
129
130 /*
131 * Mutex to protect global variables shared between various threads and
132 * processes.
133 */
134 struct mtx audit_mtx;
135
136 /*
137 * Queue of audit records ready for delivery to disk. We insert new records
138 * at the tail, and remove records from the head. Also, a count of the
139 * number of records used for checking queue depth. In addition, a counter
140 * of records that we have allocated but are not yet in the queue, which is
141 * needed to estimate the total size of the combined set of records
142 * outstanding in the system.
143 */
144 struct kaudit_queue audit_q;
145 int audit_q_len;
146 int audit_pre_q_len;
147
148 /*
149 * Audit queue control settings (minimum free, low/high water marks, etc.)
150 */
151 struct au_qctrl audit_qctrl;
152
153 /*
154 * Condition variable to signal to the worker that it has work to do: either
155 * new records are in the queue, or a log replacement is taking place.
156 */
157 struct cv audit_worker_cv;
158
159 /*
160 * Condition variable to flag when crossing the low watermark, meaning that
161 * threads blocked due to hitting the high watermark can wake up and continue
162 * to commit records.
163 */
164 struct cv audit_watermark_cv;
165
166 /*
167 * Condition variable for auditing threads wait on when in fail-stop mode.
168 * Threads wait on this CV forever (and ever), never seeing the light of day
169 * again.
170 */
171 static struct cv audit_fail_cv;
172
173 /*
174 * Optional DTrace audit provider support: function pointers for preselection
175 * and commit events.
176 */
177 #ifdef KDTRACE_HOOKS
178 void *(*dtaudit_hook_preselect)(au_id_t auid, au_event_t event,
179 au_class_t class);
180 int (*dtaudit_hook_commit)(struct kaudit_record *kar, au_id_t auid,
181 au_event_t event, au_class_t class, int sorf);
182 void (*dtaudit_hook_bsm)(struct kaudit_record *kar, au_id_t auid,
183 au_event_t event, au_class_t class, int sorf,
184 void *bsm_data, size_t bsm_lenlen);
185 #endif
186
187 /*
188 * Kernel audit information. This will store the current audit address
189 * or host information that the kernel will use when it's generating
190 * audit records. This data is modified by the A_GET{SET}KAUDIT auditon(2)
191 * command.
192 */
193 static struct auditinfo_addr audit_kinfo;
194 static struct rwlock audit_kinfo_lock;
195
196 #define KINFO_LOCK_INIT() rw_init(&audit_kinfo_lock, \
197 "audit_kinfo_lock")
198 #define KINFO_RLOCK() rw_rlock(&audit_kinfo_lock)
199 #define KINFO_WLOCK() rw_wlock(&audit_kinfo_lock)
200 #define KINFO_RUNLOCK() rw_runlock(&audit_kinfo_lock)
201 #define KINFO_WUNLOCK() rw_wunlock(&audit_kinfo_lock)
202
203 /*
204 * Check various policies to see if we should enable system-call audit hooks.
205 * Note that despite the mutex being held, we want to assign a value exactly
206 * once, as checks of the flag are performed lock-free for performance
207 * reasons. The mutex is used to get a consistent snapshot of policy state --
208 * e.g., safely accessing the two audit_trail flags.
209 */
210 void
audit_syscalls_enabled_update(void)211 audit_syscalls_enabled_update(void)
212 {
213
214 mtx_lock(&audit_mtx);
215 #ifdef KDTRACE_HOOKS
216 if (audit_dtrace_enabled)
217 audit_syscalls_enabled = true;
218 else {
219 #endif
220 if (audit_trail_enabled && !audit_trail_suspended)
221 audit_syscalls_enabled = true;
222 else
223 audit_syscalls_enabled = false;
224 #ifdef KDTRACE_HOOKS
225 }
226 #endif
227 mtx_unlock(&audit_mtx);
228 }
229
230 void
audit_set_kinfo(struct auditinfo_addr * ak)231 audit_set_kinfo(struct auditinfo_addr *ak)
232 {
233
234 KASSERT(ak->ai_termid.at_type == AU_IPv4 ||
235 ak->ai_termid.at_type == AU_IPv6,
236 ("audit_set_kinfo: invalid address type"));
237
238 KINFO_WLOCK();
239 audit_kinfo = *ak;
240 KINFO_WUNLOCK();
241 }
242
243 void
audit_get_kinfo(struct auditinfo_addr * ak)244 audit_get_kinfo(struct auditinfo_addr *ak)
245 {
246
247 KASSERT(audit_kinfo.ai_termid.at_type == AU_IPv4 ||
248 audit_kinfo.ai_termid.at_type == AU_IPv6,
249 ("audit_set_kinfo: invalid address type"));
250
251 KINFO_RLOCK();
252 *ak = audit_kinfo;
253 KINFO_RUNLOCK();
254 }
255
256 /*
257 * Construct an audit record for the passed thread.
258 */
259 static int
audit_record_ctor(void * mem,int size,void * arg,int flags)260 audit_record_ctor(void *mem, int size, void *arg, int flags)
261 {
262 struct kaudit_record *ar;
263 struct thread *td;
264 struct ucred *cred;
265 struct prison *pr;
266
267 KASSERT(sizeof(*ar) == size, ("audit_record_ctor: wrong size"));
268
269 td = arg;
270 ar = mem;
271 bzero(ar, sizeof(*ar));
272 ar->k_ar.ar_magic = AUDIT_RECORD_MAGIC;
273 nanotime(&ar->k_ar.ar_starttime);
274
275 /*
276 * Export the subject credential.
277 */
278 cred = td->td_ucred;
279 cru2x(cred, &ar->k_ar.ar_subj_cred);
280 ar->k_ar.ar_subj_ruid = cred->cr_ruid;
281 ar->k_ar.ar_subj_rgid = cred->cr_rgid;
282 ar->k_ar.ar_subj_egid = cred->cr_groups[0];
283 ar->k_ar.ar_subj_auid = cred->cr_audit.ai_auid;
284 ar->k_ar.ar_subj_asid = cred->cr_audit.ai_asid;
285 ar->k_ar.ar_subj_pid = td->td_proc->p_pid;
286 ar->k_ar.ar_subj_amask = cred->cr_audit.ai_mask;
287 ar->k_ar.ar_subj_term_addr = cred->cr_audit.ai_termid;
288 /*
289 * If this process is jailed, make sure we capture the name of the
290 * jail so we can use it to generate a zonename token when we covert
291 * this record to BSM.
292 */
293 if (jailed(cred)) {
294 pr = cred->cr_prison;
295 (void) strlcpy(ar->k_ar.ar_jailname, pr->pr_name,
296 sizeof(ar->k_ar.ar_jailname));
297 } else
298 ar->k_ar.ar_jailname[0] = '\0';
299 return (0);
300 }
301
302 static void
audit_record_dtor(void * mem,int size,void * arg)303 audit_record_dtor(void *mem, int size, void *arg)
304 {
305 struct kaudit_record *ar;
306
307 KASSERT(sizeof(*ar) == size, ("audit_record_dtor: wrong size"));
308
309 ar = mem;
310 if (ar->k_ar.ar_arg_upath1 != NULL)
311 free(ar->k_ar.ar_arg_upath1, M_AUDITPATH);
312 if (ar->k_ar.ar_arg_upath2 != NULL)
313 free(ar->k_ar.ar_arg_upath2, M_AUDITPATH);
314 if (ar->k_ar.ar_arg_text != NULL)
315 free(ar->k_ar.ar_arg_text, M_AUDITTEXT);
316 if (ar->k_udata != NULL)
317 free(ar->k_udata, M_AUDITDATA);
318 if (ar->k_ar.ar_arg_argv != NULL)
319 free(ar->k_ar.ar_arg_argv, M_AUDITTEXT);
320 if (ar->k_ar.ar_arg_envv != NULL)
321 free(ar->k_ar.ar_arg_envv, M_AUDITTEXT);
322 if (ar->k_ar.ar_arg_groups.gidset != NULL)
323 free(ar->k_ar.ar_arg_groups.gidset, M_AUDITGIDSET);
324 }
325
326 /*
327 * Initialize the Audit subsystem: configuration state, work queue,
328 * synchronization primitives, worker thread, and trigger device node. Also
329 * call into the BSM assembly code to initialize it.
330 */
331 static void
audit_init(void)332 audit_init(void)
333 {
334
335 audit_trail_enabled = 0;
336 audit_trail_suspended = 0;
337 audit_syscalls_enabled = false;
338 audit_panic_on_write_fail = 0;
339 audit_fail_stop = 0;
340 audit_in_failure = 0;
341 audit_argv = 0;
342 audit_arge = 0;
343
344 audit_fstat.af_filesz = 0; /* '0' means unset, unbounded. */
345 audit_fstat.af_currsz = 0;
346 audit_nae_mask.am_success = 0;
347 audit_nae_mask.am_failure = 0;
348
349 TAILQ_INIT(&audit_q);
350 audit_q_len = 0;
351 audit_pre_q_len = 0;
352 audit_qctrl.aq_hiwater = AQ_HIWATER;
353 audit_qctrl.aq_lowater = AQ_LOWATER;
354 audit_qctrl.aq_bufsz = AQ_BUFSZ;
355 audit_qctrl.aq_minfree = AU_FS_MINFREE;
356
357 audit_kinfo.ai_termid.at_type = AU_IPv4;
358 audit_kinfo.ai_termid.at_addr[0] = INADDR_ANY;
359
360 mtx_init(&audit_mtx, "audit_mtx", NULL, MTX_DEF);
361 KINFO_LOCK_INIT();
362 cv_init(&audit_worker_cv, "audit_worker_cv");
363 cv_init(&audit_watermark_cv, "audit_watermark_cv");
364 cv_init(&audit_fail_cv, "audit_fail_cv");
365
366 audit_record_zone = uma_zcreate("audit_record",
367 sizeof(struct kaudit_record), audit_record_ctor,
368 audit_record_dtor, NULL, NULL, UMA_ALIGN_PTR, 0);
369
370 /* First initialisation of audit_syscalls_enabled. */
371 audit_syscalls_enabled_update();
372
373 /* Initialize the BSM audit subsystem. */
374 kau_init();
375
376 audit_trigger_init();
377
378 /* Register shutdown handler. */
379 EVENTHANDLER_REGISTER(shutdown_pre_sync, audit_shutdown, NULL,
380 SHUTDOWN_PRI_FIRST);
381
382 /* Start audit worker thread. */
383 audit_worker_init();
384 }
385
386 SYSINIT(audit_init, SI_SUB_AUDIT, SI_ORDER_FIRST, audit_init, NULL);
387
388 /*
389 * Drain the audit queue and close the log at shutdown. Note that this can
390 * be called both from the system shutdown path and also from audit
391 * configuration syscalls, so 'arg' and 'howto' are ignored.
392 *
393 * XXXRW: In FreeBSD 7.x and 8.x, this fails to wait for the record queue to
394 * drain before returning, which could lead to lost records on shutdown.
395 */
396 void
audit_shutdown(void * arg,int howto)397 audit_shutdown(void *arg, int howto)
398 {
399 if (KERNEL_PANICKED())
400 return;
401 audit_rotate_vnode(NULL, NULL);
402 }
403
404 /*
405 * Return the current thread's audit record, if any.
406 */
407 struct kaudit_record *
currecord(void)408 currecord(void)
409 {
410
411 return (curthread->td_ar);
412 }
413
414 /*
415 * XXXAUDIT: Shouldn't there be logic here to sleep waiting on available
416 * pre_q space, suspending the system call until there is room?
417 */
418 struct kaudit_record *
audit_new(int event,struct thread * td)419 audit_new(int event, struct thread *td)
420 {
421 struct kaudit_record *ar;
422
423 /*
424 * Note: the number of outstanding uncommitted audit records is
425 * limited to the number of concurrent threads servicing system calls
426 * in the kernel.
427 */
428 ar = uma_zalloc_arg(audit_record_zone, td, M_WAITOK);
429 ar->k_ar.ar_event = event;
430
431 mtx_lock(&audit_mtx);
432 audit_pre_q_len++;
433 mtx_unlock(&audit_mtx);
434
435 return (ar);
436 }
437
438 void
audit_free(struct kaudit_record * ar)439 audit_free(struct kaudit_record *ar)
440 {
441
442 uma_zfree(audit_record_zone, ar);
443 }
444
445 void
audit_commit(struct kaudit_record * ar,int error,int retval)446 audit_commit(struct kaudit_record *ar, int error, int retval)
447 {
448 au_event_t event;
449 au_class_t class;
450 au_id_t auid;
451 int sorf;
452 struct au_mask *aumask;
453
454 if (ar == NULL)
455 return;
456
457 ar->k_ar.ar_errno = error;
458 ar->k_ar.ar_retval = retval;
459 nanotime(&ar->k_ar.ar_endtime);
460
461 /*
462 * Decide whether to commit the audit record by checking the error
463 * value from the system call and using the appropriate audit mask.
464 */
465 if (ar->k_ar.ar_subj_auid == AU_DEFAUDITID)
466 aumask = &audit_nae_mask;
467 else
468 aumask = &ar->k_ar.ar_subj_amask;
469
470 if (error)
471 sorf = AU_PRS_FAILURE;
472 else
473 sorf = AU_PRS_SUCCESS;
474
475 /*
476 * syscalls.master sometimes contains a prototype event number, which
477 * we will transform into a more specific event number now that we
478 * have more complete information gathered during the system call.
479 */
480 switch(ar->k_ar.ar_event) {
481 case AUE_OPEN_RWTC:
482 ar->k_ar.ar_event = audit_flags_and_error_to_openevent(
483 ar->k_ar.ar_arg_fflags, error);
484 break;
485
486 case AUE_OPENAT_RWTC:
487 ar->k_ar.ar_event = audit_flags_and_error_to_openatevent(
488 ar->k_ar.ar_arg_fflags, error);
489 break;
490
491 case AUE_SYSCTL:
492 ar->k_ar.ar_event = audit_ctlname_to_sysctlevent(
493 ar->k_ar.ar_arg_ctlname, ar->k_ar.ar_valid_arg);
494 break;
495
496 case AUE_AUDITON:
497 /* Convert the auditon() command to an event. */
498 ar->k_ar.ar_event = auditon_command_event(ar->k_ar.ar_arg_cmd);
499 break;
500
501 case AUE_MSGSYS:
502 if (ARG_IS_VALID(ar, ARG_SVIPC_WHICH))
503 ar->k_ar.ar_event =
504 audit_msgsys_to_event(ar->k_ar.ar_arg_svipc_which);
505 break;
506
507 case AUE_SEMSYS:
508 if (ARG_IS_VALID(ar, ARG_SVIPC_WHICH))
509 ar->k_ar.ar_event =
510 audit_semsys_to_event(ar->k_ar.ar_arg_svipc_which);
511 break;
512
513 case AUE_SHMSYS:
514 if (ARG_IS_VALID(ar, ARG_SVIPC_WHICH))
515 ar->k_ar.ar_event =
516 audit_shmsys_to_event(ar->k_ar.ar_arg_svipc_which);
517 break;
518 }
519
520 auid = ar->k_ar.ar_subj_auid;
521 event = ar->k_ar.ar_event;
522 class = au_event_class(event);
523
524 ar->k_ar_commit |= AR_COMMIT_KERNEL;
525 if (au_preselect(event, class, aumask, sorf) != 0)
526 ar->k_ar_commit |= AR_PRESELECT_TRAIL;
527 if (audit_pipe_preselect(auid, event, class, sorf,
528 ar->k_ar_commit & AR_PRESELECT_TRAIL) != 0)
529 ar->k_ar_commit |= AR_PRESELECT_PIPE;
530 #ifdef KDTRACE_HOOKS
531 /*
532 * Expose the audit record to DTrace, both to allow the "commit" probe
533 * to fire if it's desirable, and also to allow a decision to be made
534 * about later firing with BSM in the audit worker.
535 */
536 if (dtaudit_hook_commit != NULL) {
537 if (dtaudit_hook_commit(ar, auid, event, class, sorf) != 0)
538 ar->k_ar_commit |= AR_PRESELECT_DTRACE;
539 }
540 #endif
541
542 if ((ar->k_ar_commit & (AR_PRESELECT_TRAIL | AR_PRESELECT_PIPE |
543 AR_PRESELECT_USER_TRAIL | AR_PRESELECT_USER_PIPE |
544 AR_PRESELECT_DTRACE)) == 0) {
545 mtx_lock(&audit_mtx);
546 audit_pre_q_len--;
547 mtx_unlock(&audit_mtx);
548 audit_free(ar);
549 return;
550 }
551
552 /*
553 * Note: it could be that some records initiated while audit was
554 * enabled should still be committed?
555 *
556 * NB: The check here is not for audit_syscalls because any
557 * DTrace-related obligations have been fulfilled above -- we're just
558 * down to the trail and pipes now.
559 */
560 mtx_lock(&audit_mtx);
561 if (audit_trail_suspended || !audit_trail_enabled) {
562 audit_pre_q_len--;
563 mtx_unlock(&audit_mtx);
564 audit_free(ar);
565 return;
566 }
567
568 /*
569 * Constrain the number of committed audit records based on the
570 * configurable parameter.
571 */
572 while (audit_q_len >= audit_qctrl.aq_hiwater)
573 cv_wait(&audit_watermark_cv, &audit_mtx);
574
575 TAILQ_INSERT_TAIL(&audit_q, ar, k_q);
576 audit_q_len++;
577 audit_pre_q_len--;
578 cv_signal(&audit_worker_cv);
579 mtx_unlock(&audit_mtx);
580 }
581
582 /*
583 * audit_syscall_enter() is called on entry to each system call. It is
584 * responsible for deciding whether or not to audit the call (preselection),
585 * and if so, allocating a per-thread audit record. audit_new() will fill in
586 * basic thread/credential properties.
587 *
588 * This function will be entered only if audit_syscalls_enabled was set in the
589 * macro wrapper for this function. It could be cleared by the time this
590 * function runs, but that is an acceptable race.
591 */
592 void
audit_syscall_enter(unsigned short code,struct thread * td)593 audit_syscall_enter(unsigned short code, struct thread *td)
594 {
595 struct au_mask *aumask;
596 #ifdef KDTRACE_HOOKS
597 void *dtaudit_state;
598 #endif
599 au_class_t class;
600 au_event_t event;
601 au_id_t auid;
602 int record_needed;
603
604 KASSERT(td->td_ar == NULL, ("audit_syscall_enter: td->td_ar != NULL"));
605 KASSERT((td->td_pflags & TDP_AUDITREC) == 0,
606 ("audit_syscall_enter: TDP_AUDITREC set"));
607
608 /*
609 * In FreeBSD, each ABI has its own system call table, and hence
610 * mapping of system call codes to audit events. Convert the code to
611 * an audit event identifier using the process system call table
612 * reference. In Darwin, there's only one, so we use the global
613 * symbol for the system call table. No audit record is generated
614 * for bad system calls, as no operation has been performed.
615 */
616 if (code >= td->td_proc->p_sysent->sv_size)
617 return;
618
619 event = td->td_proc->p_sysent->sv_table[code].sy_auevent;
620 if (event == AUE_NULL)
621 return;
622
623 /*
624 * Check which audit mask to use; either the kernel non-attributable
625 * event mask or the process audit mask.
626 */
627 auid = td->td_ucred->cr_audit.ai_auid;
628 if (auid == AU_DEFAUDITID)
629 aumask = &audit_nae_mask;
630 else
631 aumask = &td->td_ucred->cr_audit.ai_mask;
632
633 /*
634 * Determine whether trail or pipe preselection would like an audit
635 * record allocated for this system call.
636 */
637 class = au_event_class(event);
638 if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
639 /*
640 * If we're out of space and need to suspend unprivileged
641 * processes, do that here rather than trying to allocate
642 * another audit record.
643 *
644 * Note: we might wish to be able to continue here in the
645 * future, if the system recovers. That should be possible
646 * by means of checking the condition in a loop around
647 * cv_wait(). It might be desirable to reevaluate whether an
648 * audit record is still required for this event by
649 * re-calling au_preselect().
650 */
651 if (audit_in_failure &&
652 priv_check(td, PRIV_AUDIT_FAILSTOP) != 0) {
653 cv_wait(&audit_fail_cv, &audit_mtx);
654 panic("audit_failing_stop: thread continued");
655 }
656 record_needed = 1;
657 } else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
658 record_needed = 1;
659 } else {
660 record_needed = 0;
661 }
662
663 /*
664 * After audit trails and pipes have made their policy choices, DTrace
665 * may request that records be generated as well. This is a slightly
666 * complex affair, as the DTrace audit provider needs the audit
667 * framework to maintain some state on the audit record, which has not
668 * been allocated at the point where the decision has to be made.
669 * This hook must run even if we are not changing the decision, as
670 * DTrace may want to stick event state onto a record we were going to
671 * produce due to the trail or pipes. The event state returned by the
672 * DTrace provider must be safe without locks held between here and
673 * below -- i.e., dtaudit_state must must refer to stable memory.
674 */
675 #ifdef KDTRACE_HOOKS
676 dtaudit_state = NULL;
677 if (dtaudit_hook_preselect != NULL) {
678 dtaudit_state = dtaudit_hook_preselect(auid, event, class);
679 if (dtaudit_state != NULL)
680 record_needed = 1;
681 }
682 #endif
683
684 /*
685 * If a record is required, allocate it and attach it to the thread
686 * for use throughout the system call. Also attach DTrace state if
687 * required.
688 *
689 * XXXRW: If we decide to reference count the evname_elem underlying
690 * dtaudit_state, we will need to free here if no record is allocated
691 * or allocatable.
692 */
693 if (record_needed) {
694 td->td_ar = audit_new(event, td);
695 if (td->td_ar != NULL) {
696 td->td_pflags |= TDP_AUDITREC;
697 #ifdef KDTRACE_HOOKS
698 td->td_ar->k_dtaudit_state = dtaudit_state;
699 #endif
700 }
701 } else
702 td->td_ar = NULL;
703 }
704
705 /*
706 * audit_syscall_exit() is called from the return of every system call, or in
707 * the event of exit1(), during the execution of exit1(). It is responsible
708 * for committing the audit record, if any, along with return condition.
709 */
710 void
audit_syscall_exit(int error,struct thread * td)711 audit_syscall_exit(int error, struct thread *td)
712 {
713 int retval;
714
715 /*
716 * Commit the audit record as desired; once we pass the record into
717 * audit_commit(), the memory is owned by the audit subsystem. The
718 * return value from the system call is stored on the user thread.
719 * If there was an error, the return value is set to -1, imitating
720 * the behavior of the cerror routine.
721 */
722 if (error)
723 retval = -1;
724 else
725 retval = td->td_retval[0];
726
727 audit_commit(td->td_ar, error, retval);
728 td->td_ar = NULL;
729 td->td_pflags &= ~TDP_AUDITREC;
730 }
731
732 void
audit_cred_copy(struct ucred * src,struct ucred * dest)733 audit_cred_copy(struct ucred *src, struct ucred *dest)
734 {
735
736 bcopy(&src->cr_audit, &dest->cr_audit, sizeof(dest->cr_audit));
737 }
738
739 void
audit_cred_destroy(struct ucred * cred)740 audit_cred_destroy(struct ucred *cred)
741 {
742
743 }
744
745 void
audit_cred_init(struct ucred * cred)746 audit_cred_init(struct ucred *cred)
747 {
748
749 bzero(&cred->cr_audit, sizeof(cred->cr_audit));
750 }
751
752 /*
753 * Initialize audit information for the first kernel process (proc 0) and for
754 * the first user process (init).
755 */
756 void
audit_cred_kproc0(struct ucred * cred)757 audit_cred_kproc0(struct ucred *cred)
758 {
759
760 cred->cr_audit.ai_auid = AU_DEFAUDITID;
761 cred->cr_audit.ai_termid.at_type = AU_IPv4;
762 }
763
764 void
audit_cred_proc1(struct ucred * cred)765 audit_cred_proc1(struct ucred *cred)
766 {
767
768 cred->cr_audit.ai_auid = AU_DEFAUDITID;
769 cred->cr_audit.ai_termid.at_type = AU_IPv4;
770 }
771
772 void
audit_thread_alloc(struct thread * td)773 audit_thread_alloc(struct thread *td)
774 {
775
776 td->td_ar = NULL;
777 }
778
779 void
audit_thread_free(struct thread * td)780 audit_thread_free(struct thread *td)
781 {
782
783 KASSERT(td->td_ar == NULL, ("audit_thread_free: td_ar != NULL"));
784 KASSERT((td->td_pflags & TDP_AUDITREC) == 0,
785 ("audit_thread_free: TDP_AUDITREC set"));
786 }
787
788 void
audit_proc_coredump(struct thread * td,char * path,int errcode)789 audit_proc_coredump(struct thread *td, char *path, int errcode)
790 {
791 struct kaudit_record *ar;
792 struct au_mask *aumask;
793 struct ucred *cred;
794 au_class_t class;
795 int ret, sorf;
796 char **pathp;
797 au_id_t auid;
798
799 ret = 0;
800
801 /*
802 * Make sure we are using the correct preselection mask.
803 */
804 cred = td->td_ucred;
805 auid = cred->cr_audit.ai_auid;
806 if (auid == AU_DEFAUDITID)
807 aumask = &audit_nae_mask;
808 else
809 aumask = &cred->cr_audit.ai_mask;
810 /*
811 * It's possible for coredump(9) generation to fail. Make sure that
812 * we handle this case correctly for preselection.
813 */
814 if (errcode != 0)
815 sorf = AU_PRS_FAILURE;
816 else
817 sorf = AU_PRS_SUCCESS;
818 class = au_event_class(AUE_CORE);
819 if (au_preselect(AUE_CORE, class, aumask, sorf) == 0 &&
820 audit_pipe_preselect(auid, AUE_CORE, class, sorf, 0) == 0)
821 return;
822
823 /*
824 * If we are interested in seeing this audit record, allocate it.
825 * Where possible coredump records should contain a pathname and arg32
826 * (signal) tokens.
827 */
828 ar = audit_new(AUE_CORE, td);
829 if (ar == NULL)
830 return;
831 if (path != NULL) {
832 pathp = &ar->k_ar.ar_arg_upath1;
833 *pathp = malloc(MAXPATHLEN, M_AUDITPATH, M_WAITOK);
834 audit_canon_path(td, AT_FDCWD, path, *pathp);
835 ARG_SET_VALID(ar, ARG_UPATH1);
836 }
837 ar->k_ar.ar_arg_signum = td->td_proc->p_sig;
838 ARG_SET_VALID(ar, ARG_SIGNUM);
839 if (errcode != 0)
840 ret = 1;
841 audit_commit(ar, errcode, ret);
842 }
843