1 /*
2 * Copyright (c) 2000-2020 Apple 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 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 * NOTICE: This file was modified by McAfee Research in 2004 to introduce
58 * support for mandatory and extensible security protections. This notice
59 * is included in support of clause 2.2 (b) of the Apple Public License,
60 * Version 2.0.
61 * Copyright (c) 2005-2006 SPARTA, Inc.
62 */
63 /*
64 */
65 /*
66 * File: ipc/ipc_object.c
67 * Author: Rich Draves
68 * Date: 1989
69 *
70 * Functions to manipulate IPC objects.
71 */
72
73 #include <mach/mach_types.h>
74 #include <mach/boolean.h>
75 #include <mach/kern_return.h>
76 #include <mach/port.h>
77 #include <mach/message.h>
78
79 #include <kern/kern_types.h>
80 #include <kern/misc_protos.h>
81 #include <kern/ipc_kobject.h>
82 #include <kern/zalloc_internal.h> // zone_id_for_element
83
84 #include <ipc/ipc_types.h>
85 #include <ipc/ipc_importance.h>
86 #include <ipc/port.h>
87 #include <ipc/ipc_space.h>
88 #include <ipc/ipc_entry.h>
89 #include <ipc/ipc_object.h>
90 #include <ipc/ipc_hash.h>
91 #include <ipc/ipc_kmsg.h>
92 #include <ipc/ipc_right.h>
93 #include <ipc/ipc_notify.h>
94 #include <ipc/ipc_policy.h>
95 #include <ipc/ipc_port.h>
96 #include <ipc/ipc_pset.h>
97
98 #include <security/mac_mach_internal.h>
99
100 static struct mpsc_daemon_queue ipc_object_deallocate_queue;
101
102 /*
103 * In order to do lockfree lookups in the IPC space, we combine two schemes:
104 *
105 * - the ipc table pointer is protected with hazard pointers to allow
106 * dereferencing it with only holding a ref on a task or space;
107 *
108 * - we use ipc_object_lock_allow_invalid in order to lock locks and validate
109 * that they are the droid we're looking for.
110 *
111 * The second half requires that virtual addresses assigned that ever held
112 * a port, either hold a port, or nothing, forever. To get this property,
113 * we just piggy back on the zone sequestering security feature which gives
114 * us exactly that.
115 *
116 * However, sequestering really only "works" on a sufficiently large address
117 * space, especially for a resource that can be made by userspace at will,
118 * so we can't do lockless lookups on ILP32.
119 *
120 * Note: this scheme is incompatible with kasan quarantines
121 * (because it uses elements to store backtraces in them
122 * which lets the waitq lock appear "valid" by accident when
123 * elements are freed).
124 */
125 #define IPC_OBJECT_ZC_BASE (ZC_ZFREE_CLEARMEM | ZC_SEQUESTER)
126
127 ZONE_DEFINE_ID(ZONE_ID_IPC_PORT, "ipc ports", struct ipc_port,
128 IPC_OBJECT_ZC_BASE | ZC_CACHING);
129
130 ZONE_DEFINE_ID(ZONE_ID_IPC_PORT_SET, "ipc port sets", struct ipc_pset,
131 IPC_OBJECT_ZC_BASE);
132
133 __attribute__((noinline))
134 static void
ipc_object_free(ipc_object_t object)135 ipc_object_free(ipc_object_t object)
136 {
137 if (io_is_any_port(object)) {
138 ipc_port_free(ip_object_to_port(object));
139 } else {
140 ipc_pset_free(ips_object_to_pset(object));
141 }
142 }
143
144 __attribute__((noinline))
145 static void
ipc_object_free_safe(ipc_object_t object)146 ipc_object_free_safe(ipc_object_t object)
147 {
148 struct waitq *wq = io_waitq(object);
149
150 assert(!waitq_is_valid(wq));
151 assert(os_atomic_load(&wq->waitq_defer.mpqc_next, relaxed) == NULL);
152 mpsc_daemon_enqueue(&ipc_object_deallocate_queue,
153 &wq->waitq_defer, MPSC_QUEUE_NONE);
154 }
155
156 static void
ipc_object_deallocate_queue_invoke(mpsc_queue_chain_t e,__assert_only mpsc_daemon_queue_t dq)157 ipc_object_deallocate_queue_invoke(mpsc_queue_chain_t e,
158 __assert_only mpsc_daemon_queue_t dq)
159 {
160 struct waitq *wq = __container_of(e, struct waitq, waitq_defer);
161 ipc_object_t io = io_from_waitq(wq);
162
163 assert(dq == &ipc_object_deallocate_queue);
164
165 os_atomic_store(&wq->waitq_defer.mpqc_next, NULL, relaxed);
166 ipc_object_free(io);
167 }
168
169 void
ipc_object_deallocate_register_queue(void)170 ipc_object_deallocate_register_queue(void)
171 {
172 thread_deallocate_daemon_register_queue(&ipc_object_deallocate_queue,
173 ipc_object_deallocate_queue_invoke);
174 }
175
176 /*
177 * Routine: ipc_object_reference
178 * Purpose:
179 * Take a reference to an object.
180 */
181
182 void
ipc_object_reference(ipc_object_t io)183 ipc_object_reference(
184 ipc_object_t io)
185 {
186 static_assert(sizeof(os_ref_atomic_t) == sizeof(io->io_references));
187 os_ref_retain_raw(&io->io_references, NULL);
188 }
189
190 /*
191 * Routine: ipc_object_release
192 * Purpose:
193 * Release a reference to an object.
194 */
195
196 void
ipc_object_release(ipc_object_t io)197 ipc_object_release(
198 ipc_object_t io)
199 {
200 #if DEBUG
201 assert(get_preemption_level() == 0);
202 #endif
203
204 if (os_ref_release_raw(&io->io_references, NULL) == 0) {
205 /* Free the object */
206 ipc_object_free(io);
207 }
208 }
209
210 /*
211 * Routine: ipc_object_release_safe
212 * Purpose:
213 * Release a reference to an object safely
214 */
215
216 void
ipc_object_release_safe(ipc_object_t io)217 ipc_object_release_safe(
218 ipc_object_t io)
219 {
220 if (os_ref_release_raw(&io->io_references, NULL) == 0) {
221 if (get_preemption_level() == 0) {
222 ipc_object_free(io);
223 } else {
224 ipc_object_free_safe(io);
225 }
226 }
227 }
228
229 /*
230 * Routine: ipc_object_release_live
231 * Purpose:
232 * Release a reference to an object that isn't the last one.
233 */
234
235 void
ipc_object_release_live(ipc_object_t io)236 ipc_object_release_live(
237 ipc_object_t io)
238 {
239 os_ref_release_live_raw(&io->io_references, NULL);
240 }
241
242 /*
243 * Routine: ipc_object_translate
244 * Purpose:
245 * Look up an object in a space.
246 * Conditions:
247 * Nothing locked before. If successful, the object
248 * is returned active and locked. The caller doesn't get a ref.
249 * Returns:
250 * KERN_SUCCESS Object returned locked.
251 * KERN_INVALID_TASK The space is dead.
252 * KERN_INVALID_NAME The name doesn't denote a right
253 * KERN_INVALID_RIGHT Name doesn't denote the correct right
254 */
255 kern_return_t
ipc_object_translate(ipc_space_t space,mach_port_name_t name,mach_port_right_t right,ipc_object_t * objectp)256 ipc_object_translate(
257 ipc_space_t space,
258 mach_port_name_t name,
259 mach_port_right_t right,
260 ipc_object_t *objectp)
261 {
262 ipc_entry_bits_t bits;
263 ipc_object_t object;
264 kern_return_t kr;
265
266 if (!MACH_PORT_RIGHT_VALID_TRANSLATE(right)) {
267 return KERN_INVALID_RIGHT;
268 }
269
270 kr = ipc_right_lookup_read(space, name, &bits, &object);
271 if (kr != KERN_SUCCESS) {
272 return kr;
273 }
274 /* object is locked and active */
275
276 if ((bits & MACH_PORT_TYPE(right)) == MACH_PORT_TYPE_NONE) {
277 io_unlock(object);
278 return KERN_INVALID_RIGHT;
279 }
280
281 *objectp = object;
282 return KERN_SUCCESS;
283 }
284
285 /*
286 * Routine: ipc_object_translate_pset_receive
287 * Purpose:
288 * Look up two objects in a space (a port set and a receive right)
289 * Conditions:
290 * Nothing locked before. If successful, the objects
291 * are returned locked. The caller doesn't get a ref.
292 * Returns:
293 * KERN_SUCCESS Objects returned locked.
294 * KERN_INVALID_TASK The space is dead.
295 * KERN_INVALID_NAME A name doesn't denote a right.
296 * KERN_INVALID_RIGHT A name doesn't denote the correct right.
297 */
298
299 kern_return_t
ipc_object_translate_port_pset(ipc_space_t space,mach_port_name_t port_name,ipc_port_t * portp,mach_port_name_t pset_name,ipc_pset_t * psetp)300 ipc_object_translate_port_pset(
301 ipc_space_t space,
302 mach_port_name_t port_name,
303 ipc_port_t *portp,
304 mach_port_name_t pset_name,
305 ipc_pset_t *psetp)
306 {
307 ipc_entry_t port_entry;
308 ipc_entry_t pset_entry;
309 ipc_port_t port;
310 ipc_pset_t pset;
311 kern_return_t kr;
312
313 kr = ipc_right_lookup_two_read(space,
314 port_name, &port_entry, pset_name, &pset_entry);
315 if (kr != KERN_SUCCESS) {
316 return kr;
317 }
318 /* space is read-locked and active */
319
320 if ((port_entry->ie_bits & MACH_PORT_TYPE_RECEIVE) == 0) {
321 bool guard = !(port_entry->ie_bits & IE_BITS_EX_RECEIVE);
322
323 is_read_unlock(space);
324 if (guard) {
325 mach_port_guard_exception(port_name,
326 MPG_PAYLOAD(MPG_FLAGS_INVALID_RIGHT_TRANSLATE_PORT,
327 port_entry->ie_bits),
328 kGUARD_EXC_INVALID_RIGHT);
329 }
330 return KERN_INVALID_RIGHT;
331 }
332
333 if ((pset_entry->ie_bits & MACH_PORT_TYPE_PORT_SET) == 0) {
334 is_read_unlock(space);
335 mach_port_guard_exception(pset_name,
336 MPG_PAYLOAD(MPG_FLAGS_INVALID_RIGHT_TRANSLATE_PSET,
337 pset_entry->ie_bits),
338 kGUARD_EXC_INVALID_RIGHT);
339 return KERN_INVALID_RIGHT;
340 }
341
342 port = port_entry->ie_port;
343 assert(port != IP_NULL);
344 ip_mq_lock(port);
345 if (!ip_active(port)) {
346 ip_mq_unlock(port);
347 is_read_unlock(space);
348 return KERN_INVALID_NAME;
349 }
350
351 pset = pset_entry->ie_pset;
352 assert(pset != IPS_NULL);
353 ips_mq_lock(pset);
354 if (!ips_active(pset)) {
355 ip_mq_unlock(port);
356 ips_mq_unlock(pset);
357 is_read_unlock(space);
358 return KERN_INVALID_NAME;
359 }
360
361 *portp = port;
362 *psetp = pset;
363
364 is_read_unlock(space);
365 return KERN_SUCCESS;
366 }
367
368 /*
369 * Routine: ipc_object_alloc_dead
370 * Purpose:
371 * Allocate a dead-name entry.
372 * Conditions:
373 * Nothing locked.
374 * Returns:
375 * KERN_SUCCESS The dead name is allocated.
376 * KERN_INVALID_TASK The space is dead.
377 * KERN_NO_SPACE No room for an entry in the space.
378 */
379
380 kern_return_t
ipc_object_alloc_dead(ipc_space_t space,mach_port_name_t * namep)381 ipc_object_alloc_dead(
382 ipc_space_t space,
383 mach_port_name_t *namep)
384 {
385 ipc_entry_t entry;
386 kern_return_t kr;
387 mach_port_type_t type = MACH_PORT_TYPE_DEAD_NAME;
388 mach_port_urefs_t urefs = 1;
389
390 kr = ipc_entry_alloc(space, IPC_OBJECT_NULL, namep, &entry);
391 if (kr != KERN_SUCCESS) {
392 return kr;
393 }
394 /* space is write-locked */
395
396 ipc_entry_init(space, IPC_OBJECT_NULL, type, entry, urefs, *namep);
397
398 is_write_unlock(space);
399 return KERN_SUCCESS;
400 }
401
402 /*
403 * Routine: ipc_object_alloc_entry
404 * Purpose:
405 * Allocate an unitialized entry for a new object.
406 * That entry must later be initialized by `ipc_entry_init` after
407 * the object has been initialized
408 * Conditions:
409 * Nothing locked.
410 * The space is write locked on successful return.
411 * Returns:
412 * KERN_SUCCESS The object is allocated.
413 * KERN_INVALID_TASK The space is dead.
414 * KERN_NO_SPACE No room for an entry in the space.
415 */
416
417 kern_return_t
ipc_object_alloc_entry(ipc_space_t space,ipc_object_t object,mach_port_name_t * namep,ipc_entry_t * entry)418 ipc_object_alloc_entry(
419 ipc_space_t space,
420 ipc_object_t object,
421 mach_port_name_t *namep,
422 ipc_entry_t *entry)
423 {
424 kern_return_t kr;
425
426 kr = ipc_entry_alloc(space, object, namep, entry);
427
428 return kr;
429 }
430
431 /*
432 * Routine: ipc_object_alloc_entry_with_name
433 * Purpose:
434 * Allocate an uninitalized entry for a new object, with a specific name.
435 * That entry must later be initialized by `ipc_entry_init` after
436 * the object has been initialized
437 * Conditions:
438 * Nothing locked.
439 * The space is write locked on successful return.
440 *
441 * Returns:
442 * KERN_SUCCESS The object is allocated.
443 * KERN_INVALID_TASK The space is dead.
444 * KERN_NAME_EXISTS The name already denotes a right.
445 */
446
447 kern_return_t
ipc_object_alloc_entry_with_name(ipc_space_t space,mach_port_name_t name,ipc_entry_t * entry)448 ipc_object_alloc_entry_with_name(
449 ipc_space_t space,
450 mach_port_name_t name,
451 ipc_entry_t *entry)
452 {
453 kern_return_t kr;
454
455 kr = ipc_entry_alloc_name(space, name, entry);
456 if (kr == KERN_SUCCESS && ipc_right_inuse(*entry)) {
457 is_write_unlock(space);
458 kr = KERN_NAME_EXISTS;
459 }
460
461 return kr;
462 }
463
464 /* Routine: ipc_object_validate
465 * Purpose:
466 * Validates an ipc port or port set as belonging to the correct
467 * zone.
468 */
469
470 void
ipc_object_validate(ipc_object_t object,ipc_object_type_t type)471 ipc_object_validate(
472 ipc_object_t object,
473 ipc_object_type_t type)
474 {
475 if (io_is_any_port_type(type)) {
476 ip_validate(object);
477 } else {
478 ips_validate(object);
479 }
480 }
481
482 /*
483 * Routine: ipc_object_copyin_type
484 * Purpose:
485 * Convert a send type name to a received type name.
486 */
487
488 mach_msg_type_name_t
ipc_object_copyin_type(mach_msg_type_name_t msgt_name)489 ipc_object_copyin_type(
490 mach_msg_type_name_t msgt_name)
491 {
492 switch (msgt_name) {
493 case MACH_MSG_TYPE_MOVE_RECEIVE:
494 return MACH_MSG_TYPE_PORT_RECEIVE;
495
496 case MACH_MSG_TYPE_MOVE_SEND_ONCE:
497 case MACH_MSG_TYPE_MAKE_SEND_ONCE:
498 return MACH_MSG_TYPE_PORT_SEND_ONCE;
499
500 case MACH_MSG_TYPE_MOVE_SEND:
501 case MACH_MSG_TYPE_MAKE_SEND:
502 case MACH_MSG_TYPE_COPY_SEND:
503 return MACH_MSG_TYPE_PORT_SEND;
504
505 default:
506 return MACH_MSG_TYPE_PORT_NONE;
507 }
508 }
509
510 /*
511 * Routine: ipc_object_copyin
512 * Purpose:
513 * Copyin a capability from a space.
514 * If successful, the caller gets a ref
515 * for the resulting port, unless it is IO_DEAD.
516 * Conditions:
517 * Nothing locked.
518 * Returns:
519 * KERN_SUCCESS Acquired a port, possibly IP_DEAD.
520 * KERN_INVALID_TASK The space is dead.
521 * KERN_INVALID_NAME Name doesn't exist in space.
522 * KERN_INVALID_RIGHT Name doesn't denote correct right.
523 */
524
525 kern_return_t
ipc_object_copyin(ipc_space_t space,mach_port_name_t name,mach_msg_type_name_t msgt_name,ipc_object_copyin_flags_t copyin_flags,ipc_copyin_op_t copyin_reason,mach_msg_guarded_port_descriptor_t * gdesc,ipc_port_t * portp)526 ipc_object_copyin(
527 ipc_space_t space,
528 mach_port_name_t name,
529 mach_msg_type_name_t msgt_name,
530 ipc_object_copyin_flags_t copyin_flags,
531 ipc_copyin_op_t copyin_reason,
532 mach_msg_guarded_port_descriptor_t *gdesc,
533 ipc_port_t *portp)
534 {
535 ipc_copyin_rcleanup_t icrc;
536 ipc_copyin_cleanup_t icc;
537 ipc_entry_t entry;
538 kern_return_t kr;
539
540 ipc_object_copyin_flags_t copyin_mask = IPC_OBJECT_COPYIN_FLAGS_ALLOW_IMMOVABLE_SEND;
541 copyin_mask = (copyin_flags & copyin_mask) | IPC_OBJECT_COPYIN_FLAGS_DEADOK;
542
543 /*
544 * Could first try a read lock when doing
545 * MACH_MSG_TYPE_COPY_SEND, MACH_MSG_TYPE_MAKE_SEND,
546 * and MACH_MSG_TYPE_MAKE_SEND_ONCE.
547 */
548
549 ipc_right_copyin_rcleanup_init(&icrc, gdesc);
550
551 kr = ipc_right_lookup_write(space, name, &entry);
552 if (kr != KERN_SUCCESS) {
553 return kr;
554 }
555 /* space is write-locked and active */
556
557 kr = ipc_right_copyin(space, name, msgt_name, copyin_mask, copyin_reason,
558 entry, portp, &icc, &icrc);
559 is_write_unlock(space);
560
561 ipc_right_copyin_cleanup_destroy(&icc, name);
562 ipc_right_copyin_rcleanup_destroy(&icrc);
563
564 return kr;
565 }
566
567 /*
568 * Routine: ipc_object_copyin_from_kernel
569 * Purpose:
570 * Copyin a naked capability from the kernel.
571 *
572 * MACH_MSG_TYPE_MOVE_RECEIVE
573 * The receiver must be ipc_space_kernel
574 * or the receive right must already be in limbo.
575 * Consumes the naked receive right.
576 * MACH_MSG_TYPE_COPY_SEND
577 * A naked send right must be supplied.
578 * The port gains a reference, and a send right
579 * if the port is still active.
580 * MACH_MSG_TYPE_MAKE_SEND
581 * The receiver must be ipc_space_kernel.
582 * The port gains a reference and a send right.
583 * MACH_MSG_TYPE_MOVE_SEND
584 * Consumes a naked send right.
585 * MACH_MSG_TYPE_MAKE_SEND_ONCE
586 * The port gains a reference and a send-once right.
587 * Receiver also be the caller of device subsystem,
588 * so no assertion.
589 * MACH_MSG_TYPE_MOVE_SEND_ONCE
590 * Consumes a naked send-once right.
591 * Conditions:
592 * Nothing locked.
593 */
594
595 void
ipc_object_copyin_from_kernel(ipc_port_t port,mach_msg_type_name_t msgt_name)596 ipc_object_copyin_from_kernel(
597 ipc_port_t port,
598 mach_msg_type_name_t msgt_name)
599 {
600 ipc_object_label_t label;
601 assert(IP_VALID(port));
602
603 switch (msgt_name) {
604 case MACH_MSG_TYPE_MOVE_RECEIVE:
605 label = ip_mq_lock_label_get(port);
606
607 if (label.io_state == IO_STATE_IN_SPACE) {
608 assert(ip_in_space(port, ipc_space_kernel));
609
610 /*
611 * Ports in kernel are never hooked to a pset,
612 * so we don't need to pass a waitq linkage free list.
613 */
614 ipc_port_mark_in_limbo(port, &label, NULL);
615 ip_mq_unlock(port);
616 } else {
617 ipc_release_assert(io_state_in_limbo(label.io_state));
618 ip_mq_unlock_label_put(port, &label);
619 }
620 break;
621
622 case MACH_MSG_TYPE_COPY_SEND:
623 ip_mq_lock(port);
624 if (ip_active(port)) {
625 assert(port->ip_srights > 0);
626 }
627 ip_srights_inc(port);
628 ip_reference(port);
629 ip_mq_unlock(port);
630 break;
631
632 case MACH_MSG_TYPE_MAKE_SEND:
633 ip_mq_lock(port);
634 if (ip_active(port)) {
635 assert(ip_in_a_space(port));
636 assert(ip_in_space(port, ipc_space_kernel));
637 port->ip_mscount++;
638 }
639
640 ip_srights_inc(port);
641 ip_reference(port);
642 ip_mq_unlock(port);
643 break;
644
645 case MACH_MSG_TYPE_MOVE_SEND:
646 /* move naked send right into the message */
647 assert(port->ip_srights);
648 break;
649
650 case MACH_MSG_TYPE_MAKE_SEND_ONCE:
651 ip_mq_lock(port);
652 if (ip_active(port)) {
653 assert(ip_in_a_space(port));
654 }
655 ipc_port_make_sonce_locked(port);
656 ip_mq_unlock(port);
657 break;
658
659 case MACH_MSG_TYPE_MOVE_SEND_ONCE:
660 /* move naked send-once right into the message */
661 assert(port->ip_sorights);
662 break;
663
664 default:
665 ipc_unreachable("ipc_object_copyin_from_kernel: strange rights");
666 }
667 }
668
669 /*
670 * Routine: ipc_object_destroy
671 * Purpose:
672 * Destroys a naked capability.
673 * Consumes a ref for the port.
674 *
675 * A receive right should be in limbo or in transit.
676 * Conditions:
677 * Nothing locked.
678 */
679
680 void
ipc_object_destroy(ipc_port_t port,mach_msg_type_name_t msgt_name)681 ipc_object_destroy(
682 ipc_port_t port,
683 mach_msg_type_name_t msgt_name)
684 {
685 assert(IP_VALID(port));
686
687 switch (msgt_name) {
688 case MACH_MSG_TYPE_PORT_SEND:
689 ipc_port_release_send(port);
690 break;
691
692 case MACH_MSG_TYPE_PORT_SEND_ONCE:
693 ip_mq_lock(port);
694 ipc_notify_send_once_and_unlock(port);
695 break;
696
697 case MACH_MSG_TYPE_PORT_RECEIVE:
698 ipc_port_release_receive(port);
699 break;
700
701 default:
702 ipc_unreachable("ipc_object_destroy: strange rights");
703 }
704 }
705
706 /*
707 * Routine: ipc_object_destroy_dest
708 * Purpose:
709 * Destroys a naked capability for the destination of
710 * of a message. Consumes a ref for the port.
711 *
712 * Conditions:
713 * Nothing locked.
714 */
715
716 void
ipc_object_destroy_dest(ipc_port_t port,mach_msg_type_name_t msgt_name)717 ipc_object_destroy_dest(
718 ipc_port_t port,
719 mach_msg_type_name_t msgt_name)
720 {
721 assert(IP_VALID(port));
722
723 switch (msgt_name) {
724 case MACH_MSG_TYPE_PORT_SEND:
725 ipc_port_release_send(port);
726 break;
727
728 case MACH_MSG_TYPE_PORT_SEND_ONCE:
729 ip_mq_lock(port);
730 ipc_notify_send_once_and_unlock(port);
731 break;
732
733 default:
734 ipc_unreachable("ipc_object_destroy_dest: strange rights");
735 }
736 }
737
738 /*
739 * Routine: ipc_object_insert_send_right
740 * Purpose:
741 * Insert a send right into an object already in the space.
742 * The specified name must already point to a valid object.
743 *
744 * Note: This really is a combined copyin()/copyout(),
745 * that avoids most of the overhead of being implemented that way.
746 *
747 * This is the fastpath for mach_port_insert_right.
748 *
749 * Conditions:
750 * Nothing locked.
751 *
752 * msgt_name must be MACH_MSG_TYPE_MAKE_SEND or
753 * MACH_MSG_TYPE_COPY_SEND.
754 *
755 * Returns:
756 * KERN_SUCCESS Copied out object, consumed ref.
757 * KERN_INVALID_TASK The space is dead.
758 * KERN_INVALID_NAME Name doesn't exist in space.
759 * KERN_INVALID_CAPABILITY The object is dead.
760 * KERN_RIGHT_EXISTS Space has rights under another name.
761 */
762 kern_return_t
ipc_object_insert_send_right(ipc_space_t space,mach_port_name_t name,mach_msg_type_name_t msgt_name)763 ipc_object_insert_send_right(
764 ipc_space_t space,
765 mach_port_name_t name,
766 mach_msg_type_name_t msgt_name)
767 {
768 ipc_entry_bits_t bits;
769 ipc_object_t object;
770 ipc_entry_t entry;
771 ipc_port_t port;
772 kern_return_t kr;
773
774 assert(msgt_name == MACH_MSG_TYPE_MAKE_SEND ||
775 msgt_name == MACH_MSG_TYPE_COPY_SEND);
776
777 kr = ipc_right_lookup_write(space, name, &entry);
778 if (kr != KERN_SUCCESS) {
779 return kr;
780 }
781 /* space is write-locked and active */
782
783 bits = entry->ie_bits;
784 object = entry->ie_object;
785
786 if (object == IPC_OBJECT_NULL) {
787 is_write_unlock(space);
788 return KERN_INVALID_CAPABILITY;
789 }
790 if ((bits & MACH_PORT_TYPE_PORT_RIGHTS) == 0) {
791 is_write_unlock(space);
792 return KERN_INVALID_RIGHT;
793 }
794
795 port = ip_object_to_port(object);
796
797 ip_mq_lock(port);
798 if (!ip_active(port)) {
799 kr = KERN_INVALID_CAPABILITY;
800 } else if (msgt_name == MACH_MSG_TYPE_MAKE_SEND) {
801 if (bits & MACH_PORT_TYPE_RECEIVE) {
802 port->ip_mscount++;
803 if ((bits & MACH_PORT_TYPE_SEND) == 0) {
804 ip_srights_inc(port);
805 bits |= MACH_PORT_TYPE_SEND;
806 }
807 /* leave urefs pegged to maximum if it overflowed */
808 if (IE_BITS_UREFS(bits) < MACH_PORT_UREFS_MAX) {
809 bits += 1; /* increment urefs */
810 }
811 entry->ie_bits = bits;
812 ipc_entry_modified(space, name, entry);
813 kr = KERN_SUCCESS;
814 } else {
815 kr = KERN_INVALID_RIGHT;
816 }
817 } else { // MACH_MSG_TYPE_COPY_SEND
818 if (bits & MACH_PORT_TYPE_SEND) {
819 /* leave urefs pegged to maximum if it overflowed */
820 if (IE_BITS_UREFS(bits) < MACH_PORT_UREFS_MAX) {
821 entry->ie_bits = bits + 1; /* increment urefs */
822 }
823 ipc_entry_modified(space, name, entry);
824 kr = KERN_SUCCESS;
825 } else {
826 kr = KERN_INVALID_RIGHT;
827 }
828 }
829
830 ip_mq_unlock(port);
831 is_write_unlock(space);
832
833 return kr;
834 }
835
836 /*
837 * Routine: ipc_object_copyout
838 * Purpose:
839 * Copyout a capability, placing it into a space.
840 * Always consumes a ref for the port.
841 * Conditions:
842 * Nothing locked.
843 * Returns:
844 * KERN_SUCCESS Copied out port, consumed ref.
845 * KERN_INVALID_TASK The space is dead.
846 * KERN_INVALID_CAPABILITY The port is dead.
847 * KERN_NO_SPACE No room in space for another right.
848 * KERN_UREFS_OVERFLOW Urefs limit exceeded
849 * and overflow wasn't specified.
850 */
851
852 kern_return_t
ipc_object_copyout(ipc_space_t space,ipc_port_t port,mach_msg_type_name_t msgt_name,ipc_object_copyout_flags_t flags,mach_msg_guarded_port_descriptor_t * gdesc,mach_port_name_t * namep)853 ipc_object_copyout(
854 ipc_space_t space,
855 ipc_port_t port,
856 mach_msg_type_name_t msgt_name,
857 ipc_object_copyout_flags_t flags,
858 mach_msg_guarded_port_descriptor_t *gdesc,
859 mach_port_name_t *namep)
860 {
861 struct knote *kn = current_thread()->ith_knote;
862 ipc_object_label_t label;
863 mach_port_name_t name;
864 ipc_entry_t entry;
865 kern_return_t kr;
866
867 assert(IP_VALID(port));
868
869 if (ITH_KNOTE_VALID(kn, msgt_name)) {
870 filt_machport_turnstile_prepare_lazily(kn, msgt_name, port);
871 }
872
873 is_write_lock(space);
874
875 for (;;) {
876 ipc_port_t port_subst = IP_NULL;
877
878 if (!is_active(space)) {
879 is_write_unlock(space);
880 kr = KERN_INVALID_TASK;
881 goto out;
882 }
883
884 kr = ipc_entries_hold(space, 1);
885 if (kr != KERN_SUCCESS) {
886 /* unlocks/locks space, so must start again */
887
888 kr = ipc_entry_grow_table(space, ITS_SIZE_NONE);
889 if (kr != KERN_SUCCESS) {
890 /* space is unlocked */
891 goto out;
892 }
893 continue;
894 }
895
896 label = ip_mq_lock_check_aligned(port);
897
898 /* Don't actually copyout rights we aren't allowed to */
899 if (!io_state_active(label.io_state) ||
900 !ip_label_check_or_substitute(space, port, &label,
901 msgt_name, &port_subst)) {
902 ip_mq_unlock_label_put(port, &label);
903 is_write_unlock(space);
904 assert(port_subst == IP_NULL);
905 kr = KERN_INVALID_CAPABILITY;
906 goto out;
907 }
908
909 /* is the kolabel requesting a substitution */
910 if (port_subst != IP_NULL) {
911 /*
912 * port is unlocked, its right consumed
913 * space is unlocked
914 */
915 assert(msgt_name == MACH_MSG_TYPE_PORT_SEND);
916 port = port_subst;
917 if (!IP_VALID(port)) {
918 port = IP_DEAD;
919 kr = KERN_INVALID_CAPABILITY;
920 goto out;
921 }
922
923 is_write_lock(space);
924 continue;
925 }
926
927 break;
928 }
929
930 /* space is write-locked and active, port is locked and active */
931
932 if ((msgt_name != MACH_MSG_TYPE_PORT_SEND_ONCE) &&
933 ipc_right_reverse(space, port, &name, &entry)) {
934 assert(entry->ie_bits & MACH_PORT_TYPE_SEND_RECEIVE);
935 } else {
936 ipc_entry_claim(space, ip_to_object(port), &name, &entry);
937 }
938
939 if (msgt_name == MACH_MSG_TYPE_PORT_RECEIVE) {
940 ipc_right_copyout_recv_and_unlock_space(space, port, &label,
941 name, entry, gdesc);
942 } else {
943 ip_label_put(port, &label);
944 ipc_right_copyout_any_send(space, port, msgt_name,
945 flags, name, entry);
946 is_write_unlock(space);
947 }
948
949 /* port is unlocked */
950
951 out:
952 if (kr == KERN_SUCCESS) {
953 *namep = name;
954 } else if (IP_VALID(port)) {
955 ipc_object_destroy(port, msgt_name);
956 }
957
958 return kr;
959 }
960
961 /*
962 * Routine: ipc_object_copyout_name
963 * Purpose:
964 * Copyout a capability, placing it into a space.
965 * The specified name is used for the capability.
966 * If successful, consumes a ref for the port.
967 * Conditions:
968 * Nothing locked.
969 * Returns:
970 * KERN_SUCCESS Copied out port, consumed ref.
971 * KERN_INVALID_TASK The space is dead.
972 * KERN_INVALID_CAPABILITY The port is dead.
973 * KERN_UREFS_OVERFLOW Urefs limit exceeded
974 * and overflow wasn't specified.
975 * KERN_RIGHT_EXISTS Space has rights under another name.
976 * KERN_NAME_EXISTS Name is already used.
977 * KERN_INVALID_VALUE Supplied port name is invalid.
978 */
979
980 kern_return_t
ipc_object_copyout_name(ipc_space_t space,ipc_port_t port,mach_msg_type_name_t msgt_name,mach_port_name_t name)981 ipc_object_copyout_name(
982 ipc_space_t space,
983 ipc_port_t port,
984 mach_msg_type_name_t msgt_name,
985 mach_port_name_t name)
986 {
987 ipc_object_label_t label;
988 mach_port_name_t oname;
989 ipc_entry_t oentry;
990 ipc_entry_t entry;
991 kern_return_t kr;
992
993 #if IMPORTANCE_INHERITANCE
994 int assertcnt = 0;
995 ipc_importance_task_t task_imp = IIT_NULL;
996 #endif /* IMPORTANCE_INHERITANCE */
997
998 assert(IP_VALID(port));
999
1000 kr = ipc_entry_alloc_name(space, name, &entry);
1001 if (kr != KERN_SUCCESS) {
1002 return kr;
1003 }
1004 /* space is write-locked and active */
1005
1006 label = ip_mq_lock_check_aligned(port);
1007
1008 /*
1009 * Don't actually copyout rights we aren't allowed to
1010 *
1011 * In particular, kolabel-ed ports do not allow callers
1012 * to pick the name they end up with.
1013 */
1014 if (!io_state_active(label.io_state) ||
1015 (io_is_kobject_type(label.io_type) && label.iol_kobject)) {
1016 ip_mq_unlock_label_put(port, &label);
1017 if (!ipc_right_inuse(entry)) {
1018 ipc_entry_dealloc(space, IPC_OBJECT_NULL, name, entry);
1019 }
1020 is_write_unlock(space);
1021 return KERN_INVALID_CAPABILITY;
1022 }
1023
1024 /* space is write-locked and active, port is locked and active */
1025
1026 if ((msgt_name != MACH_MSG_TYPE_PORT_SEND_ONCE) &&
1027 ipc_right_reverse(space, port, &oname, &oentry)) {
1028 if (name != oname) {
1029 ip_mq_unlock_label_put(port, &label);
1030 if (!ipc_right_inuse(entry)) {
1031 ipc_entry_dealloc(space, IPC_OBJECT_NULL, name, entry);
1032 }
1033 is_write_unlock(space);
1034 return KERN_RIGHT_EXISTS;
1035 }
1036
1037 assert(entry == oentry);
1038 assert(entry->ie_bits & MACH_PORT_TYPE_SEND_RECEIVE);
1039 } else if (ipc_right_inuse(entry)) {
1040 ip_mq_unlock_label_put(port, &label);
1041 is_write_unlock(space);
1042 return KERN_NAME_EXISTS;
1043 } else {
1044 assert(entry->ie_port == IP_NULL);
1045 entry->ie_port = port;
1046 }
1047
1048 if (msgt_name == MACH_MSG_TYPE_PORT_RECEIVE) {
1049 #if IMPORTANCE_INHERITANCE
1050 /*
1051 * We are slamming a receive right into the space, without
1052 * first having been enqueued on a port destined there. So,
1053 * we have to arrange to boost the task appropriately if this
1054 * port has assertions (and the task wants them).
1055 */
1056 if (space->is_task != TASK_NULL) {
1057 task_imp = space->is_task->task_imp_base;
1058 if (ipc_importance_task_is_any_receiver_type(task_imp)) {
1059 assertcnt = port->ip_impcount;
1060 ipc_importance_task_reference(task_imp);
1061 } else {
1062 task_imp = IIT_NULL;
1063 }
1064 }
1065
1066 /* take port out of limbo */
1067 port->ip_tempowner = 0;
1068
1069 #endif /* IMPORTANCE_INHERITANCE */
1070 ipc_right_copyout_recv_and_unlock_space(space, port, &label,
1071 name, entry, NULL);
1072 } else {
1073 ip_label_put(port, &label);
1074 ipc_right_copyout_any_send(space, port, msgt_name,
1075 IPC_OBJECT_COPYOUT_FLAGS_NONE, name, entry);
1076 is_write_unlock(space);
1077 }
1078
1079 #if IMPORTANCE_INHERITANCE
1080 /*
1081 * Add the assertions to the task that we captured before
1082 */
1083 if (task_imp != IIT_NULL) {
1084 ipc_importance_task_hold_internal_assertion(task_imp, assertcnt);
1085 ipc_importance_task_release(task_imp);
1086 }
1087 #endif /* IMPORTANCE_INHERITANCE */
1088
1089 return KERN_SUCCESS;
1090 }
1091
1092 /*
1093 * Routine: ipc_object_copyout_dest
1094 * Purpose:
1095 * Translates/consumes the destination right of a message.
1096 * This is unlike normal copyout because the right is consumed
1097 * in a funny way instead of being given to the receiving space.
1098 * The receiver gets his name for the port, if he has receive
1099 * rights, otherwise MACH_PORT_NULL.
1100 * Conditions:
1101 * The port is locked and active. Nothing else locked.
1102 * The port is unlocked and loses a reference.
1103 */
1104
1105 void
ipc_object_copyout_dest(ipc_space_t space,ipc_port_t port,mach_msg_type_name_t msgt_name,mach_port_name_t * namep)1106 ipc_object_copyout_dest(
1107 ipc_space_t space,
1108 ipc_port_t port,
1109 mach_msg_type_name_t msgt_name,
1110 mach_port_name_t *namep)
1111 {
1112 mach_port_name_t name;
1113
1114 assert(IP_VALID(port));
1115 assert(ip_active(port));
1116
1117 /*
1118 * If the space is the receiver/owner of the port,
1119 * then we quietly consume the right and return
1120 * the space's name for the port. Otherwise
1121 * we destroy the right and return MACH_PORT_NULL.
1122 */
1123
1124 switch (msgt_name) {
1125 case MACH_MSG_TYPE_PORT_SEND: {
1126 ipc_notify_nsenders_t nsrequest = { };
1127
1128 if (ip_in_space(port, space)) {
1129 name = ip_get_receiver_name(port);
1130 } else {
1131 name = MACH_PORT_NULL;
1132 }
1133 ip_srights_dec(port);
1134 if (port->ip_srights == 0) {
1135 nsrequest = ipc_notify_no_senders_prepare(port);
1136 }
1137 ipc_port_clear_sync_rcv_thread_boost_locked(port);
1138 /* port unlocked */
1139
1140 ipc_notify_no_senders_emit(nsrequest);
1141
1142 ip_release(port);
1143 break;
1144 }
1145
1146 case MACH_MSG_TYPE_PORT_SEND_ONCE: {
1147 if (ip_in_space(port, space)) {
1148 /* quietly consume the send-once right */
1149 ip_sorights_dec(port);
1150 name = ip_get_receiver_name(port);
1151 ipc_port_clear_sync_rcv_thread_boost_locked(port);
1152 /* port unlocked */
1153 ip_release(port);
1154 } else {
1155 /*
1156 * A very bizarre case. The message
1157 * was received, but before this copyout
1158 * happened the space lost receive rights.
1159 * We can't quietly consume the soright
1160 * out from underneath some other task,
1161 * so generate a send-once notification.
1162 */
1163
1164 ipc_notify_send_once_and_unlock(port);
1165 name = MACH_PORT_NULL;
1166 }
1167
1168 break;
1169 }
1170
1171 default:
1172 ipc_unreachable("ipc_object_copyout_dest: strange rights");
1173 }
1174
1175 *namep = name;
1176 }
1177
1178 void
ipc_object_unpin(ipc_space_t space,ipc_port_t port)1179 ipc_object_unpin(
1180 ipc_space_t space,
1181 ipc_port_t port)
1182 {
1183 mach_port_name_t name;
1184 ipc_entry_t entry;
1185
1186 if (IP_VALID(port)) {
1187 is_write_lock(space);
1188 ip_mq_lock(port);
1189
1190 if (is_active(space) &&
1191 ipc_right_reverse(space, port, &name, &entry) &&
1192 (entry->ie_bits & IE_BITS_PINNED_SEND)) {
1193 assert(entry->ie_bits & MACH_PORT_TYPE_SEND);
1194 entry->ie_bits &= ~IE_BITS_PINNED_SEND;
1195
1196 ipc_entry_modified(space, name, entry);
1197 }
1198
1199 ip_mq_unlock(port);
1200 is_write_unlock(space);
1201 }
1202 }
1203
1204 static_assert(offsetof(struct ipc_object_waitq, iowq_waitq) ==
1205 offsetof(struct ipc_port, ip_waitq));
1206 static_assert(offsetof(struct ipc_object_waitq, iowq_waitq) ==
1207 offsetof(struct ipc_pset, ips_wqset));
1208
1209 __abortlike
1210 static void
ipc_object_validate_preflight_panic(ipc_object_t io)1211 ipc_object_validate_preflight_panic(ipc_object_t io)
1212 {
1213 panic("ipc object %p is neither a port or a port-set", io);
1214 }
1215
1216 /*
1217 * Routine: ipc_object_lock_allow_invalid
1218 * Purpose:
1219 * Speculatively try to lock an object in an undefined state.
1220 *
1221 * This relies on the fact that IPC object memory is allocated
1222 * from sequestered zones, so at a given address, one can find:
1223 * 1. a valid object,
1224 * 2. a freed or invalid (uninitialized) object,
1225 * 3. unmapped memory.
1226 *
1227 * (2) is possible because the zone is made with ZC_ZFREE_CLEARMEM which
1228 * ensures freed elements are always zeroed.
1229 *
1230 * (3) is a direct courtesy of waitq_lock_allow_invalid().
1231 *
1232 * In order to disambiguate (1) from (2), we use the "waitq valid"
1233 * bit which is part of the lock. When that bit is absent,
1234 * waitq_lock() will function as expected, but
1235 * waitq_lock_allow_invalid() will not.
1236 *
1237 * Objects are then initialized and destroyed carefully so that
1238 * this "valid bit" is only set when the object invariants are
1239 * respected.
1240 *
1241 * Returns:
1242 * true: the lock was acquired
1243 * false: the object was freed or not initialized.
1244 */
1245 bool
ipc_object_lock_allow_invalid(ipc_object_t orig_io)1246 ipc_object_lock_allow_invalid(ipc_object_t orig_io)
1247 {
1248 struct waitq *wq = io_waitq(orig_io);
1249
1250 switch (zone_id_for_element(wq, sizeof(*wq))) {
1251 case ZONE_ID_IPC_PORT:
1252 case ZONE_ID_IPC_PORT_SET:
1253 break;
1254 default:
1255 ipc_object_validate_preflight_panic(orig_io);
1256 }
1257
1258 if (__probable(waitq_lock_allow_invalid(wq))) {
1259 ipc_object_t io = io_from_waitq(wq);
1260
1261 ipc_object_validate(io, io_type(io));
1262 return true;
1263 }
1264 return false;
1265 }
1266
1267 __attribute__((always_inline))
1268 void
ipc_object_unlock(ipc_object_t object)1269 ipc_object_unlock(ipc_object_t object)
1270 {
1271 release_assert(!object->io_label_lock);
1272 io_unlock_nocheck(object);
1273 }
1274