1 /*
2 * Copyright (c) 2000-2020 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28 /*
29 * @OSF_COPYRIGHT@
30 */
31 /*
32 * Mach Operating System
33 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
34 * All Rights Reserved.
35 *
36 * Permission to use, copy, modify and distribute this software and its
37 * documentation is hereby granted, provided that both the copyright
38 * notice and this permission notice appear in all copies of the
39 * software, derivative works or modified versions, and any portions
40 * thereof, and that both notices appear in supporting documentation.
41 *
42 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
43 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
44 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
45 *
46 * Carnegie Mellon requests users of this software to return to
47 *
48 * Software Distribution Coordinator or [email protected]
49 * School of Computer Science
50 * Carnegie Mellon University
51 * Pittsburgh PA 15213-3890
52 *
53 * any improvements or extensions that they make and grant Carnegie Mellon
54 * the rights to redistribute these changes.
55 */
56 /*
57 */
58
59 #include <mach/mach_types.h>
60 #include <mach/boolean.h>
61 #include <mach/kern_return.h>
62 #include <mach/message.h>
63 #include <mach/port.h>
64 #include <mach/mig_errors.h>
65 #include <mach/task.h>
66 #include <mach/thread_status.h>
67 #include <mach/exception_types.h>
68 #include <mach/exc.h>
69 #include <mach/mach_exc.h>
70
71 #include <ipc/port.h>
72 #include <ipc/ipc_entry.h>
73 #include <ipc/ipc_object.h>
74 #include <ipc/ipc_notify.h>
75 #include <ipc/ipc_space.h>
76 #include <ipc/ipc_pset.h>
77 #include <ipc/ipc_machdep.h>
78
79 #include <kern/ipc_tt.h>
80 #include <kern/task.h>
81 #include <kern/thread.h>
82 #include <kern/processor.h>
83 #include <kern/sched.h>
84 #include <kern/sched_prim.h>
85 #include <kern/host.h>
86 #include <kern/misc_protos.h>
87 #include <kern/ux_handler.h>
88 #include <kern/task_ident.h>
89
90 #include <vm/vm_map.h>
91
92 #include <security/mac_mach_internal.h>
93 #include <string.h>
94
95 #include <pexpert/pexpert.h>
96
97 #include <os/log.h>
98 #include <os/system_event_log.h>
99
100 #include <libkern/coreanalytics/coreanalytics.h>
101
102 #include <sys/code_signing.h> /* for developer mode state */
103
104 bool panic_on_exception_triage = false;
105
106 /* Not used in coded, only for inspection during debugging */
107 unsigned long c_thr_exc_raise = 0;
108 unsigned long c_thr_exc_raise_identity_token = 0;
109 unsigned long c_thr_exc_raise_state = 0;
110 unsigned long c_thr_exc_raise_state_id = 0;
111 unsigned long c_thr_exc_raise_backtrace = 0;
112
113 /* forward declarations */
114 kern_return_t exception_deliver(
115 thread_t thread,
116 exception_type_t exception,
117 mach_exception_data_t code,
118 mach_msg_type_number_t codeCnt,
119 struct exception_action *excp,
120 lck_mtx_t *mutex);
121
122 #ifdef MACH_BSD
123 kern_return_t bsd_exception(
124 exception_type_t exception,
125 mach_exception_data_t code,
126 mach_msg_type_number_t codeCnt);
127 #endif /* MACH_BSD */
128
129 #if __has_feature(ptrauth_calls)
130 extern int exit_with_pac_exception(
131 void *proc,
132 exception_type_t exception,
133 mach_exception_code_t code,
134 mach_exception_subcode_t subcode);
135 #endif /* __has_feature(ptrauth_calls) */
136
137 #ifdef MACH_BSD
138 extern bool proc_is_traced(void *p);
139 extern int proc_selfpid(void);
140 extern char *proc_name_address(struct proc *p);
141 #endif /* MACH_BSD */
142
143 #if (DEVELOPMENT || DEBUG)
144 TUNABLE_WRITEABLE(unsigned int, exception_log_max_pid, "exception_log_max_pid", 0);
145 #endif /* (DEVELOPMENT || DEBUG) */
146
147 /*
148 * Routine: exception_init
149 * Purpose:
150 * Global initialization of state for exceptions.
151 * Conditions:
152 * None.
153 */
154 void
exception_init(void)155 exception_init(void)
156 {
157 int tmp = 0;
158
159 if (PE_parse_boot_argn("-panic_on_exception_triage", &tmp, sizeof(tmp))) {
160 panic_on_exception_triage = true;
161 }
162
163 #if (DEVELOPMENT || DEBUG)
164 if (exception_log_max_pid) {
165 printf("Logging all exceptions where pid < exception_log_max_pid (%d)\n", exception_log_max_pid);
166 }
167 #endif /* (DEVELOPMENT || DEBUG) */
168 }
169
170 static TUNABLE(bool, pac_replace_ptrs_user, "pac_replace_ptrs_user", true);
171
172 ipc_port_t
exception_port_copy_send(ipc_port_t port)173 exception_port_copy_send(ipc_port_t port)
174 {
175 if (IP_VALID(port)) {
176 if (is_ux_handler_port(port)) {
177 /* is_ux_handler_port() compares against __DATA_CONST */
178 port = ipc_port_copy_send_any(port);
179 } else {
180 port = ipc_port_copy_send_mqueue(port);
181 }
182 }
183 return port;
184 }
185
186 /*
187 * Routine: exception_deliver
188 * Purpose:
189 * Make an upcall to the exception server provided.
190 * Conditions:
191 * Nothing locked and no resources held.
192 * Called from an exception context, so
193 * thread_exception_return and thread_kdb_return
194 * are possible.
195 * Returns:
196 * KERN_SUCCESS if the exception was handled
197 */
198 kern_return_t
exception_deliver(thread_t thread,exception_type_t exception,mach_exception_data_t code,mach_msg_type_number_t codeCnt,struct exception_action * excp,lck_mtx_t * mutex)199 exception_deliver(
200 thread_t thread,
201 exception_type_t exception,
202 mach_exception_data_t code,
203 mach_msg_type_number_t codeCnt,
204 struct exception_action *excp,
205 lck_mtx_t *mutex)
206 {
207 ipc_port_t exc_port = IPC_PORT_NULL;
208 exception_data_type_t small_code[EXCEPTION_CODE_MAX];
209 thread_state_t new_state = NULL;
210 int code64;
211 int behavior;
212 int flavor;
213 kern_return_t kr;
214 task_t task;
215 task_id_token_t task_token;
216 ipc_port_t thread_port = IPC_PORT_NULL,
217 task_port = IPC_PORT_NULL,
218 task_token_port = IPC_PORT_NULL;
219
220 /*
221 * Save work if we are terminating.
222 * Just go back to our AST handler.
223 */
224 if (!thread->active && !thread->inspection) {
225 return KERN_SUCCESS;
226 }
227
228 /*
229 * If there are no exception actions defined for this entity,
230 * we can't deliver here.
231 */
232 if (excp == NULL) {
233 return KERN_FAILURE;
234 }
235
236 assert(exception < EXC_TYPES_COUNT);
237 if (exception >= EXC_TYPES_COUNT) {
238 return KERN_FAILURE;
239 }
240
241 excp = &excp[exception];
242
243 /*
244 * Snapshot the exception action data under lock for consistency.
245 * Hold a reference to the port over the exception_raise_* calls
246 * so it can't be destroyed. This seems like overkill, but keeps
247 * the port from disappearing between now and when
248 * ipc_object_copyin_from_kernel is finally called.
249 */
250 lck_mtx_lock(mutex);
251 exc_port = exception_port_copy_send(excp->port);
252 if (!IP_VALID(exc_port)) {
253 lck_mtx_unlock(mutex);
254 return KERN_FAILURE;
255 }
256
257 flavor = excp->flavor;
258 behavior = excp->behavior;
259 lck_mtx_unlock(mutex);
260
261 code64 = (behavior & MACH_EXCEPTION_CODES);
262 behavior &= ~MACH_EXCEPTION_MASK;
263
264 if (!code64) {
265 small_code[0] = CAST_DOWN_EXPLICIT(exception_data_type_t, code[0]);
266 small_code[1] = CAST_DOWN_EXPLICIT(exception_data_type_t, code[1]);
267 }
268
269 task = get_threadtask(thread);
270
271 #if CONFIG_MACF
272 /* Now is a reasonably good time to check if the exception action is
273 * permitted for this process, because after this point we will send
274 * the message out almost certainly.
275 * As with other failures, exception_triage_thread will go on
276 * to the next level.
277 */
278
279 /* The global exception-to-signal translation port is safe to be an exception handler. */
280 if (is_ux_handler_port(exc_port) == FALSE &&
281 mac_exc_action_check_exception_send(task, excp) != 0) {
282 kr = KERN_FAILURE;
283 goto out_release_right;
284 }
285 #endif
286
287 thread->options |= TH_IN_MACH_EXCEPTION;
288
289 switch (behavior) {
290 case EXCEPTION_STATE: {
291 mach_msg_type_number_t old_state_cnt, new_state_cnt;
292 thread_state_data_t old_state;
293 thread_set_status_flags_t get_flags = TSSF_TRANSLATE_TO_USER;
294 thread_set_status_flags_t set_flags = TSSF_CHECK_USER_FLAGS;
295 bool task_allow_user_state = task_needs_user_signed_thread_state(task);
296
297 if (pac_replace_ptrs_user || task_allow_user_state) {
298 get_flags |= TSSF_RANDOM_USER_DIV;
299 set_flags |= (TSSF_ALLOW_ONLY_USER_PTRS | TSSF_RANDOM_USER_DIV);
300 }
301
302 c_thr_exc_raise_state++;
303 old_state_cnt = _MachineStateCount[flavor];
304 kr = thread_getstatus_to_user(thread, flavor,
305 (thread_state_t)old_state,
306 &old_state_cnt, get_flags);
307 new_state_cnt = old_state_cnt;
308 if (kr == KERN_SUCCESS) {
309 new_state = (thread_state_t)kalloc_data(sizeof(thread_state_data_t), Z_WAITOK | Z_ZERO);
310 if (new_state == NULL) {
311 kr = KERN_RESOURCE_SHORTAGE;
312 goto out_release_right;
313 }
314 if (code64) {
315 kr = mach_exception_raise_state(exc_port,
316 exception,
317 code,
318 codeCnt,
319 &flavor,
320 old_state, old_state_cnt,
321 new_state, &new_state_cnt);
322 } else {
323 kr = exception_raise_state(exc_port, exception,
324 small_code,
325 codeCnt,
326 &flavor,
327 old_state, old_state_cnt,
328 new_state, &new_state_cnt);
329 }
330 if (kr == KERN_SUCCESS) {
331 if (exception != EXC_CORPSE_NOTIFY) {
332 kr = thread_setstatus_from_user(thread, flavor,
333 (thread_state_t)new_state, new_state_cnt,
334 (thread_state_t)old_state, old_state_cnt,
335 set_flags);
336 }
337 goto out_release_right;
338 }
339 }
340
341 goto out_release_right;
342 }
343
344 case EXCEPTION_DEFAULT: {
345 c_thr_exc_raise++;
346
347 task_reference(task);
348 thread_reference(thread);
349 /*
350 * Only deliver control port if Developer Mode enabled,
351 * or task is a corpse. Otherwise we only deliver the
352 * (immovable) read port in exception handler (both in
353 * or out of process). (94669540)
354 */
355 if (developer_mode_state() || task_is_a_corpse(task)) {
356 task_port = convert_task_to_port(task);
357 thread_port = convert_thread_to_port(thread);
358 } else {
359 task_port = convert_task_read_to_port(task);
360 thread_port = convert_thread_read_to_port(thread);
361 }
362 /* task and thread ref consumed */
363
364 if (code64) {
365 kr = mach_exception_raise(exc_port,
366 thread_port,
367 task_port,
368 exception,
369 code,
370 codeCnt);
371 } else {
372 kr = exception_raise(exc_port,
373 thread_port,
374 task_port,
375 exception,
376 small_code,
377 codeCnt);
378 }
379
380 goto out_release_right;
381 }
382
383 case EXCEPTION_IDENTITY_PROTECTED: {
384 c_thr_exc_raise_identity_token++;
385
386 kr = task_create_identity_token(task, &task_token);
387 /* task_token now represents a task, or corpse */
388 assert(kr == KERN_SUCCESS);
389 task_token_port = convert_task_id_token_to_port(task_token);
390 /* task token ref consumed */
391
392 if (code64) {
393 kr = mach_exception_raise_identity_protected(exc_port,
394 thread->thread_id,
395 task_token_port,
396 exception,
397 code,
398 codeCnt);
399 } else {
400 panic("mach_exception_raise_identity_protected() must be code64");
401 }
402
403 goto out_release_right;
404 }
405
406 case EXCEPTION_STATE_IDENTITY: {
407 mach_msg_type_number_t old_state_cnt, new_state_cnt;
408 thread_state_data_t old_state;
409 thread_set_status_flags_t get_flags = TSSF_TRANSLATE_TO_USER;
410 thread_set_status_flags_t set_flags = TSSF_CHECK_USER_FLAGS;
411 bool task_allow_user_state = task_needs_user_signed_thread_state(task);
412
413 if (pac_replace_ptrs_user || task_allow_user_state) {
414 get_flags |= TSSF_RANDOM_USER_DIV;
415 set_flags |= (TSSF_ALLOW_ONLY_USER_PTRS | TSSF_RANDOM_USER_DIV);
416 }
417
418 c_thr_exc_raise_state_id++;
419
420 task_reference(task);
421 thread_reference(thread);
422 /*
423 * Only deliver control port if Developer Mode enabled,
424 * or task is a corpse. Otherwise we only deliver the
425 * (immovable) read port in exception handler (both in
426 * or out of process). (94669540)
427 */
428 if (developer_mode_state() || task_is_a_corpse(task)) {
429 task_port = convert_task_to_port(task);
430 thread_port = convert_thread_to_port(thread);
431 } else {
432 task_port = convert_task_read_to_port(task);
433 thread_port = convert_thread_read_to_port(thread);
434 }
435 /* task and thread ref consumed */
436
437 old_state_cnt = _MachineStateCount[flavor];
438 kr = thread_getstatus_to_user(thread, flavor,
439 (thread_state_t)old_state,
440 &old_state_cnt, get_flags);
441 new_state_cnt = old_state_cnt;
442 if (kr == KERN_SUCCESS) {
443 new_state = (thread_state_t)kalloc_data(sizeof(thread_state_data_t), Z_WAITOK | Z_ZERO);
444 if (new_state == NULL) {
445 kr = KERN_RESOURCE_SHORTAGE;
446 goto out_release_right;
447 }
448 if (code64) {
449 kr = mach_exception_raise_state_identity(
450 exc_port,
451 thread_port,
452 task_port,
453 exception,
454 code,
455 codeCnt,
456 &flavor,
457 old_state, old_state_cnt,
458 new_state, &new_state_cnt);
459 } else {
460 kr = exception_raise_state_identity(exc_port,
461 thread_port,
462 task_port,
463 exception,
464 small_code,
465 codeCnt,
466 &flavor,
467 old_state, old_state_cnt,
468 new_state, &new_state_cnt);
469 }
470
471 if (kr == KERN_SUCCESS) {
472 if (exception != EXC_CORPSE_NOTIFY &&
473 ip_kotype(thread_port) == IKOT_THREAD_CONTROL) {
474 kr = thread_setstatus_from_user(thread, flavor,
475 (thread_state_t)new_state, new_state_cnt,
476 (thread_state_t)old_state, old_state_cnt, set_flags);
477 }
478 goto out_release_right;
479 }
480 }
481
482 goto out_release_right;
483 }
484
485 default:
486 panic("bad exception behavior!");
487 return KERN_FAILURE;
488 }/* switch */
489
490 out_release_right:
491
492 thread->options &= ~TH_IN_MACH_EXCEPTION;
493
494 if (task_port) {
495 ipc_port_release_send(task_port);
496 }
497
498 if (thread_port) {
499 ipc_port_release_send(thread_port);
500 }
501
502 if (exc_port) {
503 ipc_port_release_send(exc_port);
504 }
505
506 if (task_token_port) {
507 ipc_port_release_send(task_token_port);
508 }
509
510 if (new_state) {
511 kfree_data(new_state, sizeof(thread_state_data_t));
512 }
513
514 return kr;
515 }
516
517 /*
518 * Attempt exception delivery with backtrace info to exception ports
519 * in exc_ports in order.
520 */
521 /*
522 * Routine: exception_deliver_backtrace
523 * Purpose:
524 * Attempt exception delivery with backtrace info to exception ports
525 * in exc_ports in order.
526 * Conditions:
527 * Caller has a reference on bt_object, and send rights on exc_ports.
528 * Does not consume any passed references or rights
529 */
530 void
exception_deliver_backtrace(kcdata_object_t bt_object,ipc_port_t exc_ports[static BT_EXC_PORTS_COUNT],exception_type_t exception)531 exception_deliver_backtrace(
532 kcdata_object_t bt_object,
533 ipc_port_t exc_ports[static BT_EXC_PORTS_COUNT],
534 exception_type_t exception)
535 {
536 kern_return_t kr;
537 mach_exception_data_type_t code[EXCEPTION_CODE_MAX];
538 ipc_port_t target_port, bt_obj_port;
539
540 assert(exception == EXC_GUARD);
541
542 code[0] = exception;
543 code[1] = 0;
544
545 kcdata_object_reference(bt_object);
546 bt_obj_port = convert_kcdata_object_to_port(bt_object);
547 /* backtrace object ref consumed, no-senders is armed */
548
549 if (!IP_VALID(bt_obj_port)) {
550 return;
551 }
552
553 /*
554 * We are guaranteed at task_enqueue_exception_with_corpse() time
555 * that the exception port prefers backtrace delivery.
556 */
557 for (unsigned int i = 0; i < BT_EXC_PORTS_COUNT; i++) {
558 target_port = exc_ports[i];
559
560 if (!IP_VALID(target_port)) {
561 continue;
562 }
563
564 ip_mq_lock(target_port);
565 if (!ip_active(target_port)) {
566 ip_mq_unlock(target_port);
567 continue;
568 }
569 ip_mq_unlock(target_port);
570
571 kr = mach_exception_raise_backtrace(target_port,
572 bt_obj_port,
573 EXC_CORPSE_NOTIFY,
574 code,
575 EXCEPTION_CODE_MAX);
576
577 if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) {
578 /* Exception is handled at this level */
579 break;
580 }
581 }
582
583 /* May trigger no-senders notification for backtrace object */
584 ipc_port_release_send(bt_obj_port);
585
586 return;
587 }
588
589 /*
590 * Routine: check_exc_receiver_dependency
591 * Purpose:
592 * Verify that the port destined for receiving this exception is not
593 * on the current task. This would cause hang in kernel for
594 * EXC_CRASH primarily. Note: If port is transferred
595 * between check and delivery then deadlock may happen.
596 *
597 * Conditions:
598 * Nothing locked and no resources held.
599 * Called from an exception context.
600 * Returns:
601 * KERN_SUCCESS if its ok to send exception message.
602 */
603 static kern_return_t
check_exc_receiver_dependency(exception_type_t exception,struct exception_action * excp,lck_mtx_t * mutex)604 check_exc_receiver_dependency(
605 exception_type_t exception,
606 struct exception_action *excp,
607 lck_mtx_t *mutex)
608 {
609 kern_return_t retval = KERN_SUCCESS;
610
611 if (excp == NULL || exception != EXC_CRASH) {
612 return retval;
613 }
614
615 task_t task = current_task();
616 lck_mtx_lock(mutex);
617 ipc_port_t xport = excp[exception].port;
618 if (IP_VALID(xport) && ip_in_space_noauth(xport, task->itk_space)) {
619 retval = KERN_FAILURE;
620 }
621 lck_mtx_unlock(mutex);
622 return retval;
623 }
624
625
626 /*
627 * Routine: exception_triage_thread
628 * Purpose:
629 * The thread caught an exception.
630 * We make an up-call to the thread's exception server.
631 * Conditions:
632 * Nothing locked and no resources held.
633 * Called from an exception context, so
634 * thread_exception_return and thread_kdb_return
635 * are possible.
636 * Returns:
637 * KERN_SUCCESS if exception is handled by any of the handlers.
638 */
639 kern_return_t
exception_triage_thread(exception_type_t exception,mach_exception_data_t code,mach_msg_type_number_t codeCnt,thread_t thread)640 exception_triage_thread(
641 exception_type_t exception,
642 mach_exception_data_t code,
643 mach_msg_type_number_t codeCnt,
644 thread_t thread)
645 {
646 task_t task;
647 thread_ro_t tro;
648 host_priv_t host_priv;
649 lck_mtx_t *mutex;
650 struct exception_action *actions;
651 kern_return_t kr = KERN_FAILURE;
652
653 assert(exception != EXC_RPC_ALERT);
654
655 /*
656 * If this behavior has been requested by the the kernel
657 * (due to the boot environment), we should panic if we
658 * enter this function. This is intended as a debugging
659 * aid; it should allow us to debug why we caught an
660 * exception in environments where debugging is especially
661 * difficult.
662 */
663 if (panic_on_exception_triage) {
664 panic("called exception_triage when it was forbidden by the boot environment");
665 }
666
667 /*
668 * Try to raise the exception at the activation level.
669 */
670 mutex = &thread->mutex;
671 tro = get_thread_ro(thread);
672 actions = tro->tro_exc_actions;
673 if (KERN_SUCCESS == check_exc_receiver_dependency(exception, actions, mutex)) {
674 kr = exception_deliver(thread, exception, code, codeCnt, actions, mutex);
675 if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) {
676 goto out;
677 }
678 }
679
680 /*
681 * Maybe the task level will handle it.
682 */
683 task = tro->tro_task;
684 mutex = &task->itk_lock_data;
685 actions = task->exc_actions;
686 if (KERN_SUCCESS == check_exc_receiver_dependency(exception, actions, mutex)) {
687 kr = exception_deliver(thread, exception, code, codeCnt, actions, mutex);
688 if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) {
689 goto out;
690 }
691 }
692
693 /*
694 * How about at the host level?
695 */
696 host_priv = host_priv_self();
697 mutex = &host_priv->lock;
698 actions = host_priv->exc_actions;
699 if (KERN_SUCCESS == check_exc_receiver_dependency(exception, actions, mutex)) {
700 kr = exception_deliver(thread, exception, code, codeCnt, actions, mutex);
701 if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) {
702 goto out;
703 }
704 }
705
706 out:
707 if ((exception != EXC_CRASH) && (exception != EXC_RESOURCE) &&
708 (exception != EXC_GUARD) && (exception != EXC_CORPSE_NOTIFY)) {
709 thread_exception_return();
710 }
711 return kr;
712 }
713
714 #if __has_feature(ptrauth_calls)
715 static TUNABLE(bool, pac_exception_telemetry, "-pac_exception_telemetry", false);
716
717 CA_EVENT(pac_exception_event,
718 CA_INT, exception,
719 CA_INT, exception_code_0,
720 CA_INT, exception_code_1,
721 CA_STATIC_STRING(CA_PROCNAME_LEN), proc_name);
722
723 static void
pac_exception_triage(exception_type_t exception,mach_exception_data_t code)724 pac_exception_triage(
725 exception_type_t exception,
726 mach_exception_data_t code)
727 {
728 boolean_t traced_flag = FALSE;
729 task_t task = current_task();
730 void *proc = get_bsdtask_info(task);
731 char *proc_name = (char *) "unknown";
732 int pid = 0;
733
734 #ifdef MACH_BSD
735 pid = proc_selfpid();
736 if (proc) {
737 traced_flag = proc_is_traced(proc);
738 /* Should only be called on current proc */
739 proc_name = proc_name_address(proc);
740
741 /*
742 * For a ptrauth violation, check if process isn't being ptraced and
743 * the task has the TFRO_PAC_EXC_FATAL flag set. If both conditions are true,
744 * terminate the task via exit_with_reason
745 */
746 if (!traced_flag) {
747 if (pac_exception_telemetry) {
748 ca_event_t ca_event = CA_EVENT_ALLOCATE(pac_exception_event);
749 CA_EVENT_TYPE(pac_exception_event) * pexc_event = ca_event->data;
750 pexc_event->exception = exception;
751 pexc_event->exception_code_0 = code[0];
752 pexc_event->exception_code_1 = code[1];
753 strlcpy(pexc_event->proc_name, proc_name, CA_PROCNAME_LEN);
754 CA_EVENT_SEND(ca_event);
755 }
756 if (task_is_pac_exception_fatal(task)) {
757 os_log_error(OS_LOG_DEFAULT, "%s: process %s[%d] hit a pac violation\n", __func__, proc_name, pid);
758 exit_with_pac_exception(proc, exception, code[0], code[1]);
759 thread_exception_return();
760 /* NOT_REACHABLE */
761 }
762 }
763 }
764 #endif /* MACH_BSD */
765 }
766 #endif /* __has_feature(ptrauth_calls) */
767
768 /*
769 * Routine: exception_triage
770 * Purpose:
771 * The current thread caught an exception.
772 * We make an up-call to the thread's exception server.
773 * Conditions:
774 * Nothing locked and no resources held.
775 * Called from an exception context, so
776 * thread_exception_return and thread_kdb_return
777 * are possible.
778 * Returns:
779 * KERN_SUCCESS if exception is handled by any of the handlers.
780 */
781 int debug4k_panic_on_exception = 0;
782 kern_return_t
exception_triage(exception_type_t exception,mach_exception_data_t code,mach_msg_type_number_t codeCnt)783 exception_triage(
784 exception_type_t exception,
785 mach_exception_data_t code,
786 mach_msg_type_number_t codeCnt)
787 {
788 thread_t thread = current_thread();
789 task_t task = current_task();
790
791 assert(codeCnt > 0);
792
793 if (VM_MAP_PAGE_SIZE(task->map) < PAGE_SIZE) {
794 DEBUG4K_EXC("thread %p task %p map %p exception %d codes 0x%llx 0x%llx\n",
795 thread, task, task->map, exception, code[0], codeCnt > 1 ? code[1] : 0);
796 if (debug4k_panic_on_exception) {
797 panic("DEBUG4K thread %p task %p map %p exception %d codes 0x%llx 0x%llx",
798 thread, task, task->map, exception, code[0], codeCnt > 1 ? code[1] : 0);
799 }
800 }
801
802 #if (DEVELOPMENT || DEBUG)
803 #ifdef MACH_BSD
804 if (proc_pid(get_bsdtask_info(task)) <= exception_log_max_pid) {
805 record_system_event(SYSTEM_EVENT_TYPE_INFO, SYSTEM_EVENT_SUBSYSTEM_PROCESS, "process exit",
806 "exception_log_max_pid: pid %d (%s): sending exception %d (0x%llx 0x%llx)",
807 proc_pid(get_bsdtask_info(task)), proc_name_address(get_bsdtask_info(task)),
808 exception, code[0], codeCnt > 1 ? code[1] : 0);
809 }
810 #endif /* MACH_BSD */
811 #endif /* DEVELOPMENT || DEBUG */
812
813 #if __has_feature(ptrauth_calls)
814 if (exception & EXC_PTRAUTH_BIT) {
815 exception &= ~EXC_PTRAUTH_BIT;
816 assert(codeCnt == 2);
817 pac_exception_triage(exception, code);
818 }
819 #endif /* __has_feature(ptrauth_calls) */
820 return exception_triage_thread(exception, code, codeCnt, thread);
821 }
822
823 kern_return_t
bsd_exception(exception_type_t exception,mach_exception_data_t code,mach_msg_type_number_t codeCnt)824 bsd_exception(
825 exception_type_t exception,
826 mach_exception_data_t code,
827 mach_msg_type_number_t codeCnt)
828 {
829 task_t task;
830 lck_mtx_t *mutex;
831 thread_t self = current_thread();
832 kern_return_t kr;
833
834 /*
835 * Maybe the task level will handle it.
836 */
837 task = current_task();
838 mutex = &task->itk_lock_data;
839
840 kr = exception_deliver(self, exception, code, codeCnt, task->exc_actions, mutex);
841
842 if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) {
843 return KERN_SUCCESS;
844 }
845 return KERN_FAILURE;
846 }
847
848
849 /*
850 * Raise an exception on a task.
851 * This should tell launchd to launch Crash Reporter for this task.
852 */
853 kern_return_t
task_exception_notify(exception_type_t exception,mach_exception_data_type_t exccode,mach_exception_data_type_t excsubcode)854 task_exception_notify(exception_type_t exception,
855 mach_exception_data_type_t exccode, mach_exception_data_type_t excsubcode)
856 {
857 mach_exception_data_type_t code[EXCEPTION_CODE_MAX];
858 wait_interrupt_t wsave;
859 kern_return_t kr = KERN_SUCCESS;
860
861 code[0] = exccode;
862 code[1] = excsubcode;
863
864 wsave = thread_interrupt_level(THREAD_UNINT);
865 kr = exception_triage(exception, code, EXCEPTION_CODE_MAX);
866 (void) thread_interrupt_level(wsave);
867 return kr;
868 }
869
870
871 /*
872 * Handle interface for special performance monitoring
873 * This is a special case of the host exception handler
874 */
875 kern_return_t
sys_perf_notify(thread_t thread,int pid)876 sys_perf_notify(thread_t thread, int pid)
877 {
878 host_priv_t hostp;
879 ipc_port_t xport;
880 wait_interrupt_t wsave;
881 kern_return_t ret;
882
883 hostp = host_priv_self(); /* Get the host privileged ports */
884 mach_exception_data_type_t code[EXCEPTION_CODE_MAX];
885 code[0] = 0xFF000001; /* Set terminate code */
886 code[1] = pid; /* Pass out the pid */
887
888 lck_mtx_lock(&hostp->lock);
889 xport = hostp->exc_actions[EXC_RPC_ALERT].port;
890
891 /* Make sure we're not catching our own exception */
892 if (!IP_VALID(xport) ||
893 !ip_active(xport) ||
894 ip_in_space_noauth(xport, get_threadtask(thread)->itk_space)) {
895 lck_mtx_unlock(&hostp->lock);
896 return KERN_FAILURE;
897 }
898
899 lck_mtx_unlock(&hostp->lock);
900
901 wsave = thread_interrupt_level(THREAD_UNINT);
902 ret = exception_deliver(
903 thread,
904 EXC_RPC_ALERT,
905 code,
906 2,
907 hostp->exc_actions,
908 &hostp->lock);
909 (void)thread_interrupt_level(wsave);
910
911 return ret;
912 }
913