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/cdefs.h>
39 #include <sys/param.h>
40 #include <sys/condvar.h>
41 #include <sys/conf.h>
42 #include <sys/eventhandler.h>
43 #include <sys/file.h>
44 #include <sys/filedesc.h>
45 #include <sys/fcntl.h>
46 #include <sys/ipc.h>
47 #include <sys/jail.h>
48 #include <sys/kernel.h>
49 #include <sys/kthread.h>
50 #include <sys/malloc.h>
51 #include <sys/mount.h>
52 #include <sys/namei.h>
53 #include <sys/priv.h>
54 #include <sys/proc.h>
55 #include <sys/queue.h>
56 #include <sys/socket.h>
57 #include <sys/socketvar.h>
58 #include <sys/protosw.h>
59 #include <sys/domain.h>
60 #include <sys/sysctl.h>
61 #include <sys/sysproto.h>
62 #include <sys/sysent.h>
63 #include <sys/systm.h>
64 #include <sys/ucred.h>
65 #include <sys/uio.h>
66 #include <sys/un.h>
67 #include <sys/unistd.h>
68 #include <sys/vnode.h>
69
70 #include <bsm/audit.h>
71 #include <bsm/audit_internal.h>
72 #include <bsm/audit_kevents.h>
73
74 #include <netinet/in.h>
75 #include <netinet/in_pcb.h>
76
77 #include <security/audit/audit.h>
78 #include <security/audit/audit_private.h>
79
80 #include <vm/uma.h>
81
82 FEATURE(audit, "BSM audit support");
83
84 static uma_zone_t audit_record_zone;
85 static MALLOC_DEFINE(M_AUDITCRED, "audit_cred", "Audit cred storage");
86 MALLOC_DEFINE(M_AUDITDATA, "audit_data", "Audit data storage");
87 MALLOC_DEFINE(M_AUDITPATH, "audit_path", "Audit path storage");
88 MALLOC_DEFINE(M_AUDITTEXT, "audit_text", "Audit text storage");
89 MALLOC_DEFINE(M_AUDITGIDSET, "audit_gidset", "Audit GID set storage");
90
91 static SYSCTL_NODE(_security, OID_AUTO, audit, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
92 "TrustedBSD audit controls");
93
94 /*
95 * Audit control settings that are set/read by system calls and are hence
96 * non-static.
97 *
98 * Define the audit control flags.
99 */
100 int audit_trail_enabled;
101 int audit_trail_suspended;
102 #ifdef KDTRACE_HOOKS
103 u_int audit_dtrace_enabled;
104 #endif
105 bool __read_frequently audit_syscalls_enabled;
106
107 /*
108 * Flags controlling behavior in low storage situations. Should we panic if
109 * a write fails? Should we fail stop if we're out of disk space?
110 */
111 int audit_panic_on_write_fail;
112 int audit_fail_stop;
113 int audit_argv;
114 int audit_arge;
115
116 /*
117 * Are we currently "failing stop" due to out of disk space?
118 */
119 int audit_in_failure;
120
121 /*
122 * Global audit statistics.
123 */
124 struct audit_fstat audit_fstat;
125
126 /*
127 * Preselection mask for non-attributable events.
128 */
129 struct au_mask audit_nae_mask;
130
131 /*
132 * Mutex to protect global variables shared between various threads and
133 * processes.
134 */
135 struct mtx audit_mtx;
136
137 /*
138 * Queue of audit records ready for delivery to disk. We insert new records
139 * at the tail, and remove records from the head. Also, a count of the
140 * number of records used for checking queue depth. In addition, a counter
141 * of records that we have allocated but are not yet in the queue, which is
142 * needed to estimate the total size of the combined set of records
143 * outstanding in the system.
144 */
145 struct kaudit_queue audit_q;
146 int audit_q_len;
147 int audit_pre_q_len;
148
149 /*
150 * Audit queue control settings (minimum free, low/high water marks, etc.)
151 */
152 struct au_qctrl audit_qctrl;
153
154 /*
155 * Condition variable to signal to the worker that it has work to do: either
156 * new records are in the queue, or a log replacement is taking place.
157 */
158 struct cv audit_worker_cv;
159
160 /*
161 * Condition variable to flag when crossing the low watermark, meaning that
162 * threads blocked due to hitting the high watermark can wake up and continue
163 * to commit records.
164 */
165 struct cv audit_watermark_cv;
166
167 /*
168 * Condition variable for auditing threads wait on when in fail-stop mode.
169 * Threads wait on this CV forever (and ever), never seeing the light of day
170 * again.
171 */
172 static struct cv audit_fail_cv;
173
174 /*
175 * Optional DTrace audit provider support: function pointers for preselection
176 * and commit events.
177 */
178 #ifdef KDTRACE_HOOKS
179 void *(*dtaudit_hook_preselect)(au_id_t auid, au_event_t event,
180 au_class_t class);
181 int (*dtaudit_hook_commit)(struct kaudit_record *kar, au_id_t auid,
182 au_event_t event, au_class_t class, int sorf);
183 void (*dtaudit_hook_bsm)(struct kaudit_record *kar, au_id_t auid,
184 au_event_t event, au_class_t class, int sorf,
185 void *bsm_data, size_t bsm_lenlen);
186 #endif
187
188 /*
189 * Kernel audit information. This will store the current audit address
190 * or host information that the kernel will use when it's generating
191 * audit records. This data is modified by the A_GET{SET}KAUDIT auditon(2)
192 * command.
193 */
194 static struct auditinfo_addr audit_kinfo;
195 static struct rwlock audit_kinfo_lock;
196
197 #define KINFO_LOCK_INIT() rw_init(&audit_kinfo_lock, \
198 "audit_kinfo_lock")
199 #define KINFO_RLOCK() rw_rlock(&audit_kinfo_lock)
200 #define KINFO_WLOCK() rw_wlock(&audit_kinfo_lock)
201 #define KINFO_RUNLOCK() rw_runlock(&audit_kinfo_lock)
202 #define KINFO_WUNLOCK() rw_wunlock(&audit_kinfo_lock)
203
204 /*
205 * Check various policies to see if we should enable system-call audit hooks.
206 * Note that despite the mutex being held, we want to assign a value exactly
207 * once, as checks of the flag are performed lock-free for performance
208 * reasons. The mutex is used to get a consistent snapshot of policy state --
209 * e.g., safely accessing the two audit_trail flags.
210 */
211 void
audit_syscalls_enabled_update(void)212 audit_syscalls_enabled_update(void)
213 {
214
215 mtx_lock(&audit_mtx);
216 #ifdef KDTRACE_HOOKS
217 if (audit_dtrace_enabled)
218 audit_syscalls_enabled = true;
219 else {
220 #endif
221 if (audit_trail_enabled && !audit_trail_suspended)
222 audit_syscalls_enabled = true;
223 else
224 audit_syscalls_enabled = false;
225 #ifdef KDTRACE_HOOKS
226 }
227 #endif
228 mtx_unlock(&audit_mtx);
229 }
230
231 void
audit_set_kinfo(struct auditinfo_addr * ak)232 audit_set_kinfo(struct auditinfo_addr *ak)
233 {
234
235 KASSERT(ak->ai_termid.at_type == AU_IPv4 ||
236 ak->ai_termid.at_type == AU_IPv6,
237 ("audit_set_kinfo: invalid address type"));
238
239 KINFO_WLOCK();
240 audit_kinfo = *ak;
241 KINFO_WUNLOCK();
242 }
243
244 void
audit_get_kinfo(struct auditinfo_addr * ak)245 audit_get_kinfo(struct auditinfo_addr *ak)
246 {
247
248 KASSERT(audit_kinfo.ai_termid.at_type == AU_IPv4 ||
249 audit_kinfo.ai_termid.at_type == AU_IPv6,
250 ("audit_set_kinfo: invalid address type"));
251
252 KINFO_RLOCK();
253 *ak = audit_kinfo;
254 KINFO_RUNLOCK();
255 }
256
257 /*
258 * Construct an audit record for the passed thread.
259 */
260 static int
audit_record_ctor(void * mem,int size,void * arg,int flags)261 audit_record_ctor(void *mem, int size, void *arg, int flags)
262 {
263 struct kaudit_record *ar;
264 struct thread *td;
265 struct ucred *cred;
266 struct prison *pr;
267
268 KASSERT(sizeof(*ar) == size, ("audit_record_ctor: wrong size"));
269
270 td = arg;
271 ar = mem;
272 bzero(ar, sizeof(*ar));
273 ar->k_ar.ar_magic = AUDIT_RECORD_MAGIC;
274 nanotime(&ar->k_ar.ar_starttime);
275
276 /*
277 * Export the subject credential.
278 */
279 cred = td->td_ucred;
280 cru2x(cred, &ar->k_ar.ar_subj_cred);
281 ar->k_ar.ar_subj_ruid = cred->cr_ruid;
282 ar->k_ar.ar_subj_rgid = cred->cr_rgid;
283 ar->k_ar.ar_subj_egid = cred->cr_groups[0];
284 ar->k_ar.ar_subj_auid = cred->cr_audit.ai_auid;
285 ar->k_ar.ar_subj_asid = cred->cr_audit.ai_asid;
286 ar->k_ar.ar_subj_pid = td->td_proc->p_pid;
287 ar->k_ar.ar_subj_amask = cred->cr_audit.ai_mask;
288 ar->k_ar.ar_subj_term_addr = cred->cr_audit.ai_termid;
289 /*
290 * If this process is jailed, make sure we capture the name of the
291 * jail so we can use it to generate a zonename token when we covert
292 * this record to BSM.
293 */
294 if (jailed(cred)) {
295 pr = cred->cr_prison;
296 (void) strlcpy(ar->k_ar.ar_jailname, pr->pr_name,
297 sizeof(ar->k_ar.ar_jailname));
298 } else
299 ar->k_ar.ar_jailname[0] = '\0';
300 return (0);
301 }
302
303 static void
audit_record_dtor(void * mem,int size,void * arg)304 audit_record_dtor(void *mem, int size, void *arg)
305 {
306 struct kaudit_record *ar;
307
308 KASSERT(sizeof(*ar) == size, ("audit_record_dtor: wrong size"));
309
310 ar = mem;
311 if (ar->k_ar.ar_arg_upath1 != NULL)
312 free(ar->k_ar.ar_arg_upath1, M_AUDITPATH);
313 if (ar->k_ar.ar_arg_upath2 != NULL)
314 free(ar->k_ar.ar_arg_upath2, M_AUDITPATH);
315 if (ar->k_ar.ar_arg_text != NULL)
316 free(ar->k_ar.ar_arg_text, M_AUDITTEXT);
317 if (ar->k_udata != NULL)
318 free(ar->k_udata, M_AUDITDATA);
319 if (ar->k_ar.ar_arg_argv != NULL)
320 free(ar->k_ar.ar_arg_argv, M_AUDITTEXT);
321 if (ar->k_ar.ar_arg_envv != NULL)
322 free(ar->k_ar.ar_arg_envv, M_AUDITTEXT);
323 if (ar->k_ar.ar_arg_groups.gidset != NULL)
324 free(ar->k_ar.ar_arg_groups.gidset, M_AUDITGIDSET);
325 }
326
327 /*
328 * Initialize the Audit subsystem: configuration state, work queue,
329 * synchronization primitives, worker thread, and trigger device node. Also
330 * call into the BSM assembly code to initialize it.
331 */
332 static void
audit_init(void)333 audit_init(void)
334 {
335
336 audit_trail_enabled = 0;
337 audit_trail_suspended = 0;
338 audit_syscalls_enabled = false;
339 audit_panic_on_write_fail = 0;
340 audit_fail_stop = 0;
341 audit_in_failure = 0;
342 audit_argv = 0;
343 audit_arge = 0;
344
345 audit_fstat.af_filesz = 0; /* '0' means unset, unbounded. */
346 audit_fstat.af_currsz = 0;
347 audit_nae_mask.am_success = 0;
348 audit_nae_mask.am_failure = 0;
349
350 TAILQ_INIT(&audit_q);
351 audit_q_len = 0;
352 audit_pre_q_len = 0;
353 audit_qctrl.aq_hiwater = AQ_HIWATER;
354 audit_qctrl.aq_lowater = AQ_LOWATER;
355 audit_qctrl.aq_bufsz = AQ_BUFSZ;
356 audit_qctrl.aq_minfree = AU_FS_MINFREE;
357
358 audit_kinfo.ai_termid.at_type = AU_IPv4;
359 audit_kinfo.ai_termid.at_addr[0] = INADDR_ANY;
360
361 mtx_init(&audit_mtx, "audit_mtx", NULL, MTX_DEF);
362 KINFO_LOCK_INIT();
363 cv_init(&audit_worker_cv, "audit_worker_cv");
364 cv_init(&audit_watermark_cv, "audit_watermark_cv");
365 cv_init(&audit_fail_cv, "audit_fail_cv");
366
367 audit_record_zone = uma_zcreate("audit_record",
368 sizeof(struct kaudit_record), audit_record_ctor,
369 audit_record_dtor, NULL, NULL, UMA_ALIGN_PTR, 0);
370
371 /* First initialisation of audit_syscalls_enabled. */
372 audit_syscalls_enabled_update();
373
374 /* Initialize the BSM audit subsystem. */
375 kau_init();
376
377 audit_trigger_init();
378
379 /* Register shutdown handler. */
380 EVENTHANDLER_REGISTER(shutdown_pre_sync, audit_shutdown, NULL,
381 SHUTDOWN_PRI_FIRST);
382
383 /* Start audit worker thread. */
384 audit_worker_init();
385 }
386
387 SYSINIT(audit_init, SI_SUB_AUDIT, SI_ORDER_FIRST, audit_init, NULL);
388
389 /*
390 * Drain the audit queue and close the log at shutdown. Note that this can
391 * be called both from the system shutdown path and also from audit
392 * configuration syscalls, so 'arg' and 'howto' are ignored.
393 *
394 * XXXRW: In FreeBSD 7.x and 8.x, this fails to wait for the record queue to
395 * drain before returning, which could lead to lost records on shutdown.
396 */
397 void
audit_shutdown(void * arg,int howto)398 audit_shutdown(void *arg, int howto)
399 {
400 if (KERNEL_PANICKED())
401 return;
402 audit_rotate_vnode(NULL, NULL);
403 }
404
405 /*
406 * Return the current thread's audit record, if any.
407 */
408 struct kaudit_record *
currecord(void)409 currecord(void)
410 {
411
412 return (curthread->td_ar);
413 }
414
415 /*
416 * XXXAUDIT: Shouldn't there be logic here to sleep waiting on available
417 * pre_q space, suspending the system call until there is room?
418 */
419 struct kaudit_record *
audit_new(int event,struct thread * td)420 audit_new(int event, struct thread *td)
421 {
422 struct kaudit_record *ar;
423
424 /*
425 * Note: the number of outstanding uncommitted audit records is
426 * limited to the number of concurrent threads servicing system calls
427 * in the kernel.
428 */
429 ar = uma_zalloc_arg(audit_record_zone, td, M_WAITOK);
430 ar->k_ar.ar_event = event;
431
432 mtx_lock(&audit_mtx);
433 audit_pre_q_len++;
434 mtx_unlock(&audit_mtx);
435
436 return (ar);
437 }
438
439 void
audit_free(struct kaudit_record * ar)440 audit_free(struct kaudit_record *ar)
441 {
442
443 uma_zfree(audit_record_zone, ar);
444 }
445
446 void
audit_commit(struct kaudit_record * ar,int error,int retval)447 audit_commit(struct kaudit_record *ar, int error, int retval)
448 {
449 au_event_t event;
450 au_class_t class;
451 au_id_t auid;
452 int sorf;
453 struct au_mask *aumask;
454
455 if (ar == NULL)
456 return;
457
458 ar->k_ar.ar_errno = error;
459 ar->k_ar.ar_retval = retval;
460 nanotime(&ar->k_ar.ar_endtime);
461
462 /*
463 * Decide whether to commit the audit record by checking the error
464 * value from the system call and using the appropriate audit mask.
465 */
466 if (ar->k_ar.ar_subj_auid == AU_DEFAUDITID)
467 aumask = &audit_nae_mask;
468 else
469 aumask = &ar->k_ar.ar_subj_amask;
470
471 if (error)
472 sorf = AU_PRS_FAILURE;
473 else
474 sorf = AU_PRS_SUCCESS;
475
476 /*
477 * syscalls.master sometimes contains a prototype event number, which
478 * we will transform into a more specific event number now that we
479 * have more complete information gathered during the system call.
480 */
481 switch(ar->k_ar.ar_event) {
482 case AUE_OPEN_RWTC:
483 ar->k_ar.ar_event = audit_flags_and_error_to_openevent(
484 ar->k_ar.ar_arg_fflags, error);
485 break;
486
487 case AUE_OPENAT_RWTC:
488 ar->k_ar.ar_event = audit_flags_and_error_to_openatevent(
489 ar->k_ar.ar_arg_fflags, error);
490 break;
491
492 case AUE_SYSCTL:
493 ar->k_ar.ar_event = audit_ctlname_to_sysctlevent(
494 ar->k_ar.ar_arg_ctlname, ar->k_ar.ar_valid_arg);
495 break;
496
497 case AUE_AUDITON:
498 /* Convert the auditon() command to an event. */
499 ar->k_ar.ar_event = auditon_command_event(ar->k_ar.ar_arg_cmd);
500 break;
501
502 case AUE_MSGSYS:
503 if (ARG_IS_VALID(ar, ARG_SVIPC_WHICH))
504 ar->k_ar.ar_event =
505 audit_msgsys_to_event(ar->k_ar.ar_arg_svipc_which);
506 break;
507
508 case AUE_SEMSYS:
509 if (ARG_IS_VALID(ar, ARG_SVIPC_WHICH))
510 ar->k_ar.ar_event =
511 audit_semsys_to_event(ar->k_ar.ar_arg_svipc_which);
512 break;
513
514 case AUE_SHMSYS:
515 if (ARG_IS_VALID(ar, ARG_SVIPC_WHICH))
516 ar->k_ar.ar_event =
517 audit_shmsys_to_event(ar->k_ar.ar_arg_svipc_which);
518 break;
519 }
520
521 auid = ar->k_ar.ar_subj_auid;
522 event = ar->k_ar.ar_event;
523 class = au_event_class(event);
524
525 ar->k_ar_commit |= AR_COMMIT_KERNEL;
526 if (au_preselect(event, class, aumask, sorf) != 0)
527 ar->k_ar_commit |= AR_PRESELECT_TRAIL;
528 if (audit_pipe_preselect(auid, event, class, sorf,
529 ar->k_ar_commit & AR_PRESELECT_TRAIL) != 0)
530 ar->k_ar_commit |= AR_PRESELECT_PIPE;
531 #ifdef KDTRACE_HOOKS
532 /*
533 * Expose the audit record to DTrace, both to allow the "commit" probe
534 * to fire if it's desirable, and also to allow a decision to be made
535 * about later firing with BSM in the audit worker.
536 */
537 if (dtaudit_hook_commit != NULL) {
538 if (dtaudit_hook_commit(ar, auid, event, class, sorf) != 0)
539 ar->k_ar_commit |= AR_PRESELECT_DTRACE;
540 }
541 #endif
542
543 if ((ar->k_ar_commit & (AR_PRESELECT_TRAIL | AR_PRESELECT_PIPE |
544 AR_PRESELECT_USER_TRAIL | AR_PRESELECT_USER_PIPE |
545 AR_PRESELECT_DTRACE)) == 0) {
546 mtx_lock(&audit_mtx);
547 audit_pre_q_len--;
548 mtx_unlock(&audit_mtx);
549 audit_free(ar);
550 return;
551 }
552
553 /*
554 * Note: it could be that some records initiated while audit was
555 * enabled should still be committed?
556 *
557 * NB: The check here is not for audit_syscalls because any
558 * DTrace-related obligations have been fulfilled above -- we're just
559 * down to the trail and pipes now.
560 */
561 mtx_lock(&audit_mtx);
562 if (audit_trail_suspended || !audit_trail_enabled) {
563 audit_pre_q_len--;
564 mtx_unlock(&audit_mtx);
565 audit_free(ar);
566 return;
567 }
568
569 /*
570 * Constrain the number of committed audit records based on the
571 * configurable parameter.
572 */
573 while (audit_q_len >= audit_qctrl.aq_hiwater)
574 cv_wait(&audit_watermark_cv, &audit_mtx);
575
576 TAILQ_INSERT_TAIL(&audit_q, ar, k_q);
577 audit_q_len++;
578 audit_pre_q_len--;
579 cv_signal(&audit_worker_cv);
580 mtx_unlock(&audit_mtx);
581 }
582
583 /*
584 * audit_syscall_enter() is called on entry to each system call. It is
585 * responsible for deciding whether or not to audit the call (preselection),
586 * and if so, allocating a per-thread audit record. audit_new() will fill in
587 * basic thread/credential properties.
588 *
589 * This function will be entered only if audit_syscalls_enabled was set in the
590 * macro wrapper for this function. It could be cleared by the time this
591 * function runs, but that is an acceptable race.
592 */
593 void
audit_syscall_enter(unsigned short code,struct thread * td)594 audit_syscall_enter(unsigned short code, struct thread *td)
595 {
596 struct au_mask *aumask;
597 #ifdef KDTRACE_HOOKS
598 void *dtaudit_state;
599 #endif
600 au_class_t class;
601 au_event_t event;
602 au_id_t auid;
603 int record_needed;
604
605 KASSERT(td->td_ar == NULL, ("audit_syscall_enter: td->td_ar != NULL"));
606 KASSERT((td->td_pflags & TDP_AUDITREC) == 0,
607 ("audit_syscall_enter: TDP_AUDITREC set"));
608
609 /*
610 * In FreeBSD, each ABI has its own system call table, and hence
611 * mapping of system call codes to audit events. Convert the code to
612 * an audit event identifier using the process system call table
613 * reference. In Darwin, there's only one, so we use the global
614 * symbol for the system call table. No audit record is generated
615 * for bad system calls, as no operation has been performed.
616 */
617 if (code >= td->td_proc->p_sysent->sv_size)
618 return;
619
620 event = td->td_proc->p_sysent->sv_table[code].sy_auevent;
621 if (event == AUE_NULL)
622 return;
623
624 /*
625 * Check which audit mask to use; either the kernel non-attributable
626 * event mask or the process audit mask.
627 */
628 auid = td->td_ucred->cr_audit.ai_auid;
629 if (auid == AU_DEFAUDITID)
630 aumask = &audit_nae_mask;
631 else
632 aumask = &td->td_ucred->cr_audit.ai_mask;
633
634 /*
635 * Determine whether trail or pipe preselection would like an audit
636 * record allocated for this system call.
637 */
638 class = au_event_class(event);
639 if (au_preselect(event, class, aumask, AU_PRS_BOTH)) {
640 /*
641 * If we're out of space and need to suspend unprivileged
642 * processes, do that here rather than trying to allocate
643 * another audit record.
644 *
645 * Note: we might wish to be able to continue here in the
646 * future, if the system recovers. That should be possible
647 * by means of checking the condition in a loop around
648 * cv_wait(). It might be desirable to reevaluate whether an
649 * audit record is still required for this event by
650 * re-calling au_preselect().
651 */
652 if (audit_in_failure &&
653 priv_check(td, PRIV_AUDIT_FAILSTOP) != 0) {
654 cv_wait(&audit_fail_cv, &audit_mtx);
655 panic("audit_failing_stop: thread continued");
656 }
657 record_needed = 1;
658 } else if (audit_pipe_preselect(auid, event, class, AU_PRS_BOTH, 0)) {
659 record_needed = 1;
660 } else {
661 record_needed = 0;
662 }
663
664 /*
665 * After audit trails and pipes have made their policy choices, DTrace
666 * may request that records be generated as well. This is a slightly
667 * complex affair, as the DTrace audit provider needs the audit
668 * framework to maintain some state on the audit record, which has not
669 * been allocated at the point where the decision has to be made.
670 * This hook must run even if we are not changing the decision, as
671 * DTrace may want to stick event state onto a record we were going to
672 * produce due to the trail or pipes. The event state returned by the
673 * DTrace provider must be safe without locks held between here and
674 * below -- i.e., dtaudit_state must must refer to stable memory.
675 */
676 #ifdef KDTRACE_HOOKS
677 dtaudit_state = NULL;
678 if (dtaudit_hook_preselect != NULL) {
679 dtaudit_state = dtaudit_hook_preselect(auid, event, class);
680 if (dtaudit_state != NULL)
681 record_needed = 1;
682 }
683 #endif
684
685 /*
686 * If a record is required, allocate it and attach it to the thread
687 * for use throughout the system call. Also attach DTrace state if
688 * required.
689 *
690 * XXXRW: If we decide to reference count the evname_elem underlying
691 * dtaudit_state, we will need to free here if no record is allocated
692 * or allocatable.
693 */
694 if (record_needed) {
695 td->td_ar = audit_new(event, td);
696 if (td->td_ar != NULL) {
697 td->td_pflags |= TDP_AUDITREC;
698 #ifdef KDTRACE_HOOKS
699 td->td_ar->k_dtaudit_state = dtaudit_state;
700 #endif
701 }
702 } else
703 td->td_ar = NULL;
704 }
705
706 /*
707 * audit_syscall_exit() is called from the return of every system call, or in
708 * the event of exit1(), during the execution of exit1(). It is responsible
709 * for committing the audit record, if any, along with return condition.
710 */
711 void
audit_syscall_exit(int error,struct thread * td)712 audit_syscall_exit(int error, struct thread *td)
713 {
714 int retval;
715
716 /*
717 * Commit the audit record as desired; once we pass the record into
718 * audit_commit(), the memory is owned by the audit subsystem. The
719 * return value from the system call is stored on the user thread.
720 * If there was an error, the return value is set to -1, imitating
721 * the behavior of the cerror routine.
722 */
723 if (error)
724 retval = -1;
725 else
726 retval = td->td_retval[0];
727
728 audit_commit(td->td_ar, error, retval);
729 td->td_ar = NULL;
730 td->td_pflags &= ~TDP_AUDITREC;
731 }
732
733 void
audit_cred_copy(struct ucred * src,struct ucred * dest)734 audit_cred_copy(struct ucred *src, struct ucred *dest)
735 {
736
737 bcopy(&src->cr_audit, &dest->cr_audit, sizeof(dest->cr_audit));
738 }
739
740 void
audit_cred_destroy(struct ucred * cred)741 audit_cred_destroy(struct ucred *cred)
742 {
743
744 }
745
746 void
audit_cred_init(struct ucred * cred)747 audit_cred_init(struct ucred *cred)
748 {
749
750 bzero(&cred->cr_audit, sizeof(cred->cr_audit));
751 }
752
753 /*
754 * Initialize audit information for the first kernel process (proc 0) and for
755 * the first user process (init).
756 */
757 void
audit_cred_kproc0(struct ucred * cred)758 audit_cred_kproc0(struct ucred *cred)
759 {
760
761 cred->cr_audit.ai_auid = AU_DEFAUDITID;
762 cred->cr_audit.ai_termid.at_type = AU_IPv4;
763 }
764
765 void
audit_cred_proc1(struct ucred * cred)766 audit_cred_proc1(struct ucred *cred)
767 {
768
769 cred->cr_audit.ai_auid = AU_DEFAUDITID;
770 cred->cr_audit.ai_termid.at_type = AU_IPv4;
771 }
772
773 void
audit_thread_alloc(struct thread * td)774 audit_thread_alloc(struct thread *td)
775 {
776
777 td->td_ar = NULL;
778 }
779
780 void
audit_thread_free(struct thread * td)781 audit_thread_free(struct thread *td)
782 {
783
784 KASSERT(td->td_ar == NULL, ("audit_thread_free: td_ar != NULL"));
785 KASSERT((td->td_pflags & TDP_AUDITREC) == 0,
786 ("audit_thread_free: TDP_AUDITREC set"));
787 }
788
789 void
audit_proc_coredump(struct thread * td,char * path,int errcode)790 audit_proc_coredump(struct thread *td, char *path, int errcode)
791 {
792 struct kaudit_record *ar;
793 struct au_mask *aumask;
794 struct ucred *cred;
795 au_class_t class;
796 int ret, sorf;
797 char **pathp;
798 au_id_t auid;
799
800 ret = 0;
801
802 /*
803 * Make sure we are using the correct preselection mask.
804 */
805 cred = td->td_ucred;
806 auid = cred->cr_audit.ai_auid;
807 if (auid == AU_DEFAUDITID)
808 aumask = &audit_nae_mask;
809 else
810 aumask = &cred->cr_audit.ai_mask;
811 /*
812 * It's possible for coredump(9) generation to fail. Make sure that
813 * we handle this case correctly for preselection.
814 */
815 if (errcode != 0)
816 sorf = AU_PRS_FAILURE;
817 else
818 sorf = AU_PRS_SUCCESS;
819 class = au_event_class(AUE_CORE);
820 if (au_preselect(AUE_CORE, class, aumask, sorf) == 0 &&
821 audit_pipe_preselect(auid, AUE_CORE, class, sorf, 0) == 0)
822 return;
823
824 /*
825 * If we are interested in seeing this audit record, allocate it.
826 * Where possible coredump records should contain a pathname and arg32
827 * (signal) tokens.
828 */
829 ar = audit_new(AUE_CORE, td);
830 if (ar == NULL)
831 return;
832 if (path != NULL) {
833 pathp = &ar->k_ar.ar_arg_upath1;
834 *pathp = malloc(MAXPATHLEN, M_AUDITPATH, M_WAITOK);
835 audit_canon_path(td, AT_FDCWD, path, *pathp);
836 ARG_SET_VALID(ar, ARG_UPATH1);
837 }
838 ar->k_ar.ar_arg_signum = td->td_proc->p_sig;
839 ARG_SET_VALID(ar, ARG_SIGNUM);
840 if (errcode != 0)
841 ret = 1;
842 audit_commit(ar, errcode, ret);
843 }
844