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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/ipc/msg.c
4 * Copyright (C) 1992 Krishna Balasubramanian
5 *
6 * Removed all the remaining kerneld mess
7 * Catch the -EFAULT stuff properly
8 * Use GFP_KERNEL for messages as in 1.2
9 * Fixed up the unchecked user space derefs
10 * Copyright (C) 1998 Alan Cox & Andi Kleen
11 *
12 * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
13 *
14 * mostly rewritten, threaded and wake-one semantics added
15 * MSGMAX limit removed, sysctl's added
16 * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
17 *
18 * support for audit of ipc object properties and permission changes
19 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
20 *
21 * namespaces support
22 * OpenVZ, SWsoft Inc.
23 * Pavel Emelianov <xemul@openvz.org>
24 */
25
26#include <linux/capability.h>
27#include <linux/msg.h>
28#include <linux/spinlock.h>
29#include <linux/init.h>
30#include <linux/mm.h>
31#include <linux/proc_fs.h>
32#include <linux/list.h>
33#include <linux/security.h>
34#include <linux/sched/wake_q.h>
35#include <linux/syscalls.h>
36#include <linux/audit.h>
37#include <linux/seq_file.h>
38#include <linux/rwsem.h>
39#include <linux/nsproxy.h>
40#include <linux/ipc_namespace.h>
41#include <linux/rhashtable.h>
42
43#include <asm/current.h>
44#include <linux/uaccess.h>
45#include "util.h"
46
47/* one msq_queue structure for each present queue on the system */
48struct msg_queue {
49 struct kern_ipc_perm q_perm;
50 time64_t q_stime; /* last msgsnd time */
51 time64_t q_rtime; /* last msgrcv time */
52 time64_t q_ctime; /* last change time */
53 unsigned long q_cbytes; /* current number of bytes on queue */
54 unsigned long q_qnum; /* number of messages in queue */
55 unsigned long q_qbytes; /* max number of bytes on queue */
56 struct pid *q_lspid; /* pid of last msgsnd */
57 struct pid *q_lrpid; /* last receive pid */
58
59 struct list_head q_messages;
60 struct list_head q_receivers;
61 struct list_head q_senders;
62} __randomize_layout;
63
64/*
65 * MSG_BARRIER Locking:
66 *
67 * Similar to the optimization used in ipc/mqueue.c, one syscall return path
68 * does not acquire any locks when it sees that a message exists in
69 * msg_receiver.r_msg. Therefore r_msg is set using smp_store_release()
70 * and accessed using READ_ONCE()+smp_acquire__after_ctrl_dep(). In addition,
71 * wake_q_add_safe() is used. See ipc/mqueue.c for more details
72 */
73
74/* one msg_receiver structure for each sleeping receiver */
75struct msg_receiver {
76 struct list_head r_list;
77 struct task_struct *r_tsk;
78
79 int r_mode;
80 long r_msgtype;
81 long r_maxsize;
82
83 struct msg_msg *r_msg;
84};
85
86/* one msg_sender for each sleeping sender */
87struct msg_sender {
88 struct list_head list;
89 struct task_struct *tsk;
90 size_t msgsz;
91};
92
93#define SEARCH_ANY 1
94#define SEARCH_EQUAL 2
95#define SEARCH_NOTEQUAL 3
96#define SEARCH_LESSEQUAL 4
97#define SEARCH_NUMBER 5
98
99#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
100
101static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
102{
103 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&msg_ids(ns), id);
104
105 if (IS_ERR(ipcp))
106 return ERR_CAST(ipcp);
107
108 return container_of(ipcp, struct msg_queue, q_perm);
109}
110
111static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
112 int id)
113{
114 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
115
116 if (IS_ERR(ipcp))
117 return ERR_CAST(ipcp);
118
119 return container_of(ipcp, struct msg_queue, q_perm);
120}
121
122static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
123{
124 ipc_rmid(&msg_ids(ns), &s->q_perm);
125}
126
127static void msg_rcu_free(struct rcu_head *head)
128{
129 struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
130 struct msg_queue *msq = container_of(p, struct msg_queue, q_perm);
131
132 security_msg_queue_free(&msq->q_perm);
133 kvfree(msq);
134}
135
136/**
137 * newque - Create a new msg queue
138 * @ns: namespace
139 * @params: ptr to the structure that contains the key and msgflg
140 *
141 * Called with msg_ids.rwsem held (writer)
142 */
143static int newque(struct ipc_namespace *ns, struct ipc_params *params)
144{
145 struct msg_queue *msq;
146 int retval;
147 key_t key = params->key;
148 int msgflg = params->flg;
149
150 msq = kvmalloc(sizeof(*msq), GFP_KERNEL);
151 if (unlikely(!msq))
152 return -ENOMEM;
153
154 msq->q_perm.mode = msgflg & S_IRWXUGO;
155 msq->q_perm.key = key;
156
157 msq->q_perm.security = NULL;
158 retval = security_msg_queue_alloc(&msq->q_perm);
159 if (retval) {
160 kvfree(msq);
161 return retval;
162 }
163
164 msq->q_stime = msq->q_rtime = 0;
165 msq->q_ctime = ktime_get_real_seconds();
166 msq->q_cbytes = msq->q_qnum = 0;
167 msq->q_qbytes = ns->msg_ctlmnb;
168 msq->q_lspid = msq->q_lrpid = NULL;
169 INIT_LIST_HEAD(&msq->q_messages);
170 INIT_LIST_HEAD(&msq->q_receivers);
171 INIT_LIST_HEAD(&msq->q_senders);
172
173 /* ipc_addid() locks msq upon success. */
174 retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
175 if (retval < 0) {
176 ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
177 return retval;
178 }
179
180 ipc_unlock_object(&msq->q_perm);
181 rcu_read_unlock();
182
183 return msq->q_perm.id;
184}
185
186static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz)
187{
188 return msgsz + msq->q_cbytes <= msq->q_qbytes &&
189 1 + msq->q_qnum <= msq->q_qbytes;
190}
191
192static inline void ss_add(struct msg_queue *msq,
193 struct msg_sender *mss, size_t msgsz)
194{
195 mss->tsk = current;
196 mss->msgsz = msgsz;
197 /*
198 * No memory barrier required: we did ipc_lock_object(),
199 * and the waker obtains that lock before calling wake_q_add().
200 */
201 __set_current_state(TASK_INTERRUPTIBLE);
202 list_add_tail(&mss->list, &msq->q_senders);
203}
204
205static inline void ss_del(struct msg_sender *mss)
206{
207 if (mss->list.next)
208 list_del(&mss->list);
209}
210
211static void ss_wakeup(struct msg_queue *msq,
212 struct wake_q_head *wake_q, bool kill)
213{
214 struct msg_sender *mss, *t;
215 struct task_struct *stop_tsk = NULL;
216 struct list_head *h = &msq->q_senders;
217
218 list_for_each_entry_safe(mss, t, h, list) {
219 if (kill)
220 mss->list.next = NULL;
221
222 /*
223 * Stop at the first task we don't wakeup,
224 * we've already iterated the original
225 * sender queue.
226 */
227 else if (stop_tsk == mss->tsk)
228 break;
229 /*
230 * We are not in an EIDRM scenario here, therefore
231 * verify that we really need to wakeup the task.
232 * To maintain current semantics and wakeup order,
233 * move the sender to the tail on behalf of the
234 * blocked task.
235 */
236 else if (!msg_fits_inqueue(msq, mss->msgsz)) {
237 if (!stop_tsk)
238 stop_tsk = mss->tsk;
239
240 list_move_tail(&mss->list, &msq->q_senders);
241 continue;
242 }
243
244 wake_q_add(wake_q, mss->tsk);
245 }
246}
247
248static void expunge_all(struct msg_queue *msq, int res,
249 struct wake_q_head *wake_q)
250{
251 struct msg_receiver *msr, *t;
252
253 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
254 get_task_struct(msr->r_tsk);
255
256 /* see MSG_BARRIER for purpose/pairing */
257 smp_store_release(&msr->r_msg, ERR_PTR(res));
258 wake_q_add_safe(wake_q, msr->r_tsk);
259 }
260}
261
262/*
263 * freeque() wakes up waiters on the sender and receiver waiting queue,
264 * removes the message queue from message queue ID IDR, and cleans up all the
265 * messages associated with this queue.
266 *
267 * msg_ids.rwsem (writer) and the spinlock for this message queue are held
268 * before freeque() is called. msg_ids.rwsem remains locked on exit.
269 */
270static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
271 __releases(RCU)
272 __releases(&msq->q_perm)
273{
274 struct msg_msg *msg, *t;
275 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
276 DEFINE_WAKE_Q(wake_q);
277
278 expunge_all(msq, -EIDRM, &wake_q);
279 ss_wakeup(msq, &wake_q, true);
280 msg_rmid(ns, msq);
281 ipc_unlock_object(&msq->q_perm);
282 wake_up_q(&wake_q);
283 rcu_read_unlock();
284
285 list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
286 atomic_dec(&ns->msg_hdrs);
287 free_msg(msg);
288 }
289 atomic_sub(msq->q_cbytes, &ns->msg_bytes);
290 ipc_update_pid(&msq->q_lspid, NULL);
291 ipc_update_pid(&msq->q_lrpid, NULL);
292 ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
293}
294
295long ksys_msgget(key_t key, int msgflg)
296{
297 struct ipc_namespace *ns;
298 static const struct ipc_ops msg_ops = {
299 .getnew = newque,
300 .associate = security_msg_queue_associate,
301 };
302 struct ipc_params msg_params;
303
304 ns = current->nsproxy->ipc_ns;
305
306 msg_params.key = key;
307 msg_params.flg = msgflg;
308
309 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
310}
311
312SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
313{
314 return ksys_msgget(key, msgflg);
315}
316
317static inline unsigned long
318copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
319{
320 switch (version) {
321 case IPC_64:
322 return copy_to_user(buf, in, sizeof(*in));
323 case IPC_OLD:
324 {
325 struct msqid_ds out;
326
327 memset(&out, 0, sizeof(out));
328
329 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
330
331 out.msg_stime = in->msg_stime;
332 out.msg_rtime = in->msg_rtime;
333 out.msg_ctime = in->msg_ctime;
334
335 if (in->msg_cbytes > USHRT_MAX)
336 out.msg_cbytes = USHRT_MAX;
337 else
338 out.msg_cbytes = in->msg_cbytes;
339 out.msg_lcbytes = in->msg_cbytes;
340
341 if (in->msg_qnum > USHRT_MAX)
342 out.msg_qnum = USHRT_MAX;
343 else
344 out.msg_qnum = in->msg_qnum;
345
346 if (in->msg_qbytes > USHRT_MAX)
347 out.msg_qbytes = USHRT_MAX;
348 else
349 out.msg_qbytes = in->msg_qbytes;
350 out.msg_lqbytes = in->msg_qbytes;
351
352 out.msg_lspid = in->msg_lspid;
353 out.msg_lrpid = in->msg_lrpid;
354
355 return copy_to_user(buf, &out, sizeof(out));
356 }
357 default:
358 return -EINVAL;
359 }
360}
361
362static inline unsigned long
363copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
364{
365 switch (version) {
366 case IPC_64:
367 if (copy_from_user(out, buf, sizeof(*out)))
368 return -EFAULT;
369 return 0;
370 case IPC_OLD:
371 {
372 struct msqid_ds tbuf_old;
373
374 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
375 return -EFAULT;
376
377 out->msg_perm.uid = tbuf_old.msg_perm.uid;
378 out->msg_perm.gid = tbuf_old.msg_perm.gid;
379 out->msg_perm.mode = tbuf_old.msg_perm.mode;
380
381 if (tbuf_old.msg_qbytes == 0)
382 out->msg_qbytes = tbuf_old.msg_lqbytes;
383 else
384 out->msg_qbytes = tbuf_old.msg_qbytes;
385
386 return 0;
387 }
388 default:
389 return -EINVAL;
390 }
391}
392
393/*
394 * This function handles some msgctl commands which require the rwsem
395 * to be held in write mode.
396 * NOTE: no locks must be held, the rwsem is taken inside this function.
397 */
398static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
399 struct ipc64_perm *perm, int msg_qbytes)
400{
401 struct kern_ipc_perm *ipcp;
402 struct msg_queue *msq;
403 int err;
404
405 down_write(&msg_ids(ns).rwsem);
406 rcu_read_lock();
407
408 ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd,
409 perm, msg_qbytes);
410 if (IS_ERR(ipcp)) {
411 err = PTR_ERR(ipcp);
412 goto out_unlock1;
413 }
414
415 msq = container_of(ipcp, struct msg_queue, q_perm);
416
417 err = security_msg_queue_msgctl(&msq->q_perm, cmd);
418 if (err)
419 goto out_unlock1;
420
421 switch (cmd) {
422 case IPC_RMID:
423 ipc_lock_object(&msq->q_perm);
424 /* freeque unlocks the ipc object and rcu */
425 freeque(ns, ipcp);
426 goto out_up;
427 case IPC_SET:
428 {
429 DEFINE_WAKE_Q(wake_q);
430
431 if (msg_qbytes > ns->msg_ctlmnb &&
432 !capable(CAP_SYS_RESOURCE)) {
433 err = -EPERM;
434 goto out_unlock1;
435 }
436
437 ipc_lock_object(&msq->q_perm);
438 err = ipc_update_perm(perm, ipcp);
439 if (err)
440 goto out_unlock0;
441
442 msq->q_qbytes = msg_qbytes;
443
444 msq->q_ctime = ktime_get_real_seconds();
445 /*
446 * Sleeping receivers might be excluded by
447 * stricter permissions.
448 */
449 expunge_all(msq, -EAGAIN, &wake_q);
450 /*
451 * Sleeping senders might be able to send
452 * due to a larger queue size.
453 */
454 ss_wakeup(msq, &wake_q, false);
455 ipc_unlock_object(&msq->q_perm);
456 wake_up_q(&wake_q);
457
458 goto out_unlock1;
459 }
460 default:
461 err = -EINVAL;
462 goto out_unlock1;
463 }
464
465out_unlock0:
466 ipc_unlock_object(&msq->q_perm);
467out_unlock1:
468 rcu_read_unlock();
469out_up:
470 up_write(&msg_ids(ns).rwsem);
471 return err;
472}
473
474static int msgctl_info(struct ipc_namespace *ns, int msqid,
475 int cmd, struct msginfo *msginfo)
476{
477 int err;
478 int max_idx;
479
480 /*
481 * We must not return kernel stack data.
482 * due to padding, it's not enough
483 * to set all member fields.
484 */
485 err = security_msg_queue_msgctl(NULL, cmd);
486 if (err)
487 return err;
488
489 memset(msginfo, 0, sizeof(*msginfo));
490 msginfo->msgmni = ns->msg_ctlmni;
491 msginfo->msgmax = ns->msg_ctlmax;
492 msginfo->msgmnb = ns->msg_ctlmnb;
493 msginfo->msgssz = MSGSSZ;
494 msginfo->msgseg = MSGSEG;
495 down_read(&msg_ids(ns).rwsem);
496 if (cmd == MSG_INFO) {
497 msginfo->msgpool = msg_ids(ns).in_use;
498 msginfo->msgmap = atomic_read(&ns->msg_hdrs);
499 msginfo->msgtql = atomic_read(&ns->msg_bytes);
500 } else {
501 msginfo->msgmap = MSGMAP;
502 msginfo->msgpool = MSGPOOL;
503 msginfo->msgtql = MSGTQL;
504 }
505 max_idx = ipc_get_maxidx(&msg_ids(ns));
506 up_read(&msg_ids(ns).rwsem);
507 return (max_idx < 0) ? 0 : max_idx;
508}
509
510static int msgctl_stat(struct ipc_namespace *ns, int msqid,
511 int cmd, struct msqid64_ds *p)
512{
513 struct msg_queue *msq;
514 int err;
515
516 memset(p, 0, sizeof(*p));
517
518 rcu_read_lock();
519 if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) {
520 msq = msq_obtain_object(ns, msqid);
521 if (IS_ERR(msq)) {
522 err = PTR_ERR(msq);
523 goto out_unlock;
524 }
525 } else { /* IPC_STAT */
526 msq = msq_obtain_object_check(ns, msqid);
527 if (IS_ERR(msq)) {
528 err = PTR_ERR(msq);
529 goto out_unlock;
530 }
531 }
532
533 /* see comment for SHM_STAT_ANY */
534 if (cmd == MSG_STAT_ANY)
535 audit_ipc_obj(&msq->q_perm);
536 else {
537 err = -EACCES;
538 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
539 goto out_unlock;
540 }
541
542 err = security_msg_queue_msgctl(&msq->q_perm, cmd);
543 if (err)
544 goto out_unlock;
545
546 ipc_lock_object(&msq->q_perm);
547
548 if (!ipc_valid_object(&msq->q_perm)) {
549 ipc_unlock_object(&msq->q_perm);
550 err = -EIDRM;
551 goto out_unlock;
552 }
553
554 kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm);
555 p->msg_stime = msq->q_stime;
556 p->msg_rtime = msq->q_rtime;
557 p->msg_ctime = msq->q_ctime;
558#ifndef CONFIG_64BIT
559 p->msg_stime_high = msq->q_stime >> 32;
560 p->msg_rtime_high = msq->q_rtime >> 32;
561 p->msg_ctime_high = msq->q_ctime >> 32;
562#endif
563 p->msg_cbytes = msq->q_cbytes;
564 p->msg_qnum = msq->q_qnum;
565 p->msg_qbytes = msq->q_qbytes;
566 p->msg_lspid = pid_vnr(msq->q_lspid);
567 p->msg_lrpid = pid_vnr(msq->q_lrpid);
568
569 if (cmd == IPC_STAT) {
570 /*
571 * As defined in SUS:
572 * Return 0 on success
573 */
574 err = 0;
575 } else {
576 /*
577 * MSG_STAT and MSG_STAT_ANY (both Linux specific)
578 * Return the full id, including the sequence number
579 */
580 err = msq->q_perm.id;
581 }
582
583 ipc_unlock_object(&msq->q_perm);
584out_unlock:
585 rcu_read_unlock();
586 return err;
587}
588
589static long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf, int version)
590{
591 struct ipc_namespace *ns;
592 struct msqid64_ds msqid64;
593 int err;
594
595 if (msqid < 0 || cmd < 0)
596 return -EINVAL;
597
598 ns = current->nsproxy->ipc_ns;
599
600 switch (cmd) {
601 case IPC_INFO:
602 case MSG_INFO: {
603 struct msginfo msginfo;
604 err = msgctl_info(ns, msqid, cmd, &msginfo);
605 if (err < 0)
606 return err;
607 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
608 err = -EFAULT;
609 return err;
610 }
611 case MSG_STAT: /* msqid is an index rather than a msg queue id */
612 case MSG_STAT_ANY:
613 case IPC_STAT:
614 err = msgctl_stat(ns, msqid, cmd, &msqid64);
615 if (err < 0)
616 return err;
617 if (copy_msqid_to_user(buf, &msqid64, version))
618 err = -EFAULT;
619 return err;
620 case IPC_SET:
621 if (copy_msqid_from_user(&msqid64, buf, version))
622 return -EFAULT;
623 return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm,
624 msqid64.msg_qbytes);
625 case IPC_RMID:
626 return msgctl_down(ns, msqid, cmd, NULL, 0);
627 default:
628 return -EINVAL;
629 }
630}
631
632SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
633{
634 return ksys_msgctl(msqid, cmd, buf, IPC_64);
635}
636
637#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
638long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
639{
640 int version = ipc_parse_version(&cmd);
641
642 return ksys_msgctl(msqid, cmd, buf, version);
643}
644
645SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
646{
647 return ksys_old_msgctl(msqid, cmd, buf);
648}
649#endif
650
651#ifdef CONFIG_COMPAT
652
653struct compat_msqid_ds {
654 struct compat_ipc_perm msg_perm;
655 compat_uptr_t msg_first;
656 compat_uptr_t msg_last;
657 old_time32_t msg_stime;
658 old_time32_t msg_rtime;
659 old_time32_t msg_ctime;
660 compat_ulong_t msg_lcbytes;
661 compat_ulong_t msg_lqbytes;
662 unsigned short msg_cbytes;
663 unsigned short msg_qnum;
664 unsigned short msg_qbytes;
665 compat_ipc_pid_t msg_lspid;
666 compat_ipc_pid_t msg_lrpid;
667};
668
669static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf,
670 int version)
671{
672 memset(out, 0, sizeof(*out));
673 if (version == IPC_64) {
674 struct compat_msqid64_ds __user *p = buf;
675 if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm))
676 return -EFAULT;
677 if (get_user(out->msg_qbytes, &p->msg_qbytes))
678 return -EFAULT;
679 } else {
680 struct compat_msqid_ds __user *p = buf;
681 if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm))
682 return -EFAULT;
683 if (get_user(out->msg_qbytes, &p->msg_qbytes))
684 return -EFAULT;
685 }
686 return 0;
687}
688
689static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in,
690 int version)
691{
692 if (version == IPC_64) {
693 struct compat_msqid64_ds v;
694 memset(&v, 0, sizeof(v));
695 to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm);
696 v.msg_stime = lower_32_bits(in->msg_stime);
697 v.msg_stime_high = upper_32_bits(in->msg_stime);
698 v.msg_rtime = lower_32_bits(in->msg_rtime);
699 v.msg_rtime_high = upper_32_bits(in->msg_rtime);
700 v.msg_ctime = lower_32_bits(in->msg_ctime);
701 v.msg_ctime_high = upper_32_bits(in->msg_ctime);
702 v.msg_cbytes = in->msg_cbytes;
703 v.msg_qnum = in->msg_qnum;
704 v.msg_qbytes = in->msg_qbytes;
705 v.msg_lspid = in->msg_lspid;
706 v.msg_lrpid = in->msg_lrpid;
707 return copy_to_user(buf, &v, sizeof(v));
708 } else {
709 struct compat_msqid_ds v;
710 memset(&v, 0, sizeof(v));
711 to_compat_ipc_perm(&v.msg_perm, &in->msg_perm);
712 v.msg_stime = in->msg_stime;
713 v.msg_rtime = in->msg_rtime;
714 v.msg_ctime = in->msg_ctime;
715 v.msg_cbytes = in->msg_cbytes;
716 v.msg_qnum = in->msg_qnum;
717 v.msg_qbytes = in->msg_qbytes;
718 v.msg_lspid = in->msg_lspid;
719 v.msg_lrpid = in->msg_lrpid;
720 return copy_to_user(buf, &v, sizeof(v));
721 }
722}
723
724static long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr, int version)
725{
726 struct ipc_namespace *ns;
727 int err;
728 struct msqid64_ds msqid64;
729
730 ns = current->nsproxy->ipc_ns;
731
732 if (msqid < 0 || cmd < 0)
733 return -EINVAL;
734
735 switch (cmd & (~IPC_64)) {
736 case IPC_INFO:
737 case MSG_INFO: {
738 struct msginfo msginfo;
739 err = msgctl_info(ns, msqid, cmd, &msginfo);
740 if (err < 0)
741 return err;
742 if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo)))
743 err = -EFAULT;
744 return err;
745 }
746 case IPC_STAT:
747 case MSG_STAT:
748 case MSG_STAT_ANY:
749 err = msgctl_stat(ns, msqid, cmd, &msqid64);
750 if (err < 0)
751 return err;
752 if (copy_compat_msqid_to_user(uptr, &msqid64, version))
753 err = -EFAULT;
754 return err;
755 case IPC_SET:
756 if (copy_compat_msqid_from_user(&msqid64, uptr, version))
757 return -EFAULT;
758 return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes);
759 case IPC_RMID:
760 return msgctl_down(ns, msqid, cmd, NULL, 0);
761 default:
762 return -EINVAL;
763 }
764}
765
766COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)
767{
768 return compat_ksys_msgctl(msqid, cmd, uptr, IPC_64);
769}
770
771#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
772long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr)
773{
774 int version = compat_ipc_parse_version(&cmd);
775
776 return compat_ksys_msgctl(msqid, cmd, uptr, version);
777}
778
779COMPAT_SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, void __user *, uptr)
780{
781 return compat_ksys_old_msgctl(msqid, cmd, uptr);
782}
783#endif
784#endif
785
786static int testmsg(struct msg_msg *msg, long type, int mode)
787{
788 switch (mode) {
789 case SEARCH_ANY:
790 case SEARCH_NUMBER:
791 return 1;
792 case SEARCH_LESSEQUAL:
793 if (msg->m_type <= type)
794 return 1;
795 break;
796 case SEARCH_EQUAL:
797 if (msg->m_type == type)
798 return 1;
799 break;
800 case SEARCH_NOTEQUAL:
801 if (msg->m_type != type)
802 return 1;
803 break;
804 }
805 return 0;
806}
807
808static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg,
809 struct wake_q_head *wake_q)
810{
811 struct msg_receiver *msr, *t;
812
813 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
814 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
815 !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk,
816 msr->r_msgtype, msr->r_mode)) {
817
818 list_del(&msr->r_list);
819 if (msr->r_maxsize < msg->m_ts) {
820 wake_q_add(wake_q, msr->r_tsk);
821
822 /* See expunge_all regarding memory barrier */
823 smp_store_release(&msr->r_msg, ERR_PTR(-E2BIG));
824 } else {
825 ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk));
826 msq->q_rtime = ktime_get_real_seconds();
827
828 wake_q_add(wake_q, msr->r_tsk);
829
830 /* See expunge_all regarding memory barrier */
831 smp_store_release(&msr->r_msg, msg);
832 return 1;
833 }
834 }
835 }
836
837 return 0;
838}
839
840static long do_msgsnd(int msqid, long mtype, void __user *mtext,
841 size_t msgsz, int msgflg)
842{
843 struct msg_queue *msq;
844 struct msg_msg *msg;
845 int err;
846 struct ipc_namespace *ns;
847 DEFINE_WAKE_Q(wake_q);
848
849 ns = current->nsproxy->ipc_ns;
850
851 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
852 return -EINVAL;
853 if (mtype < 1)
854 return -EINVAL;
855
856 msg = load_msg(mtext, msgsz);
857 if (IS_ERR(msg))
858 return PTR_ERR(msg);
859
860 msg->m_type = mtype;
861 msg->m_ts = msgsz;
862
863 rcu_read_lock();
864 msq = msq_obtain_object_check(ns, msqid);
865 if (IS_ERR(msq)) {
866 err = PTR_ERR(msq);
867 goto out_unlock1;
868 }
869
870 ipc_lock_object(&msq->q_perm);
871
872 for (;;) {
873 struct msg_sender s;
874
875 err = -EACCES;
876 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
877 goto out_unlock0;
878
879 /* raced with RMID? */
880 if (!ipc_valid_object(&msq->q_perm)) {
881 err = -EIDRM;
882 goto out_unlock0;
883 }
884
885 err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg);
886 if (err)
887 goto out_unlock0;
888
889 if (msg_fits_inqueue(msq, msgsz))
890 break;
891
892 /* queue full, wait: */
893 if (msgflg & IPC_NOWAIT) {
894 err = -EAGAIN;
895 goto out_unlock0;
896 }
897
898 /* enqueue the sender and prepare to block */
899 ss_add(msq, &s, msgsz);
900
901 if (!ipc_rcu_getref(&msq->q_perm)) {
902 err = -EIDRM;
903 goto out_unlock0;
904 }
905
906 ipc_unlock_object(&msq->q_perm);
907 rcu_read_unlock();
908 schedule();
909
910 rcu_read_lock();
911 ipc_lock_object(&msq->q_perm);
912
913 ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
914 /* raced with RMID? */
915 if (!ipc_valid_object(&msq->q_perm)) {
916 err = -EIDRM;
917 goto out_unlock0;
918 }
919 ss_del(&s);
920
921 if (signal_pending(current)) {
922 err = -ERESTARTNOHAND;
923 goto out_unlock0;
924 }
925
926 }
927
928 ipc_update_pid(&msq->q_lspid, task_tgid(current));
929 msq->q_stime = ktime_get_real_seconds();
930
931 if (!pipelined_send(msq, msg, &wake_q)) {
932 /* no one is waiting for this message, enqueue it */
933 list_add_tail(&msg->m_list, &msq->q_messages);
934 msq->q_cbytes += msgsz;
935 msq->q_qnum++;
936 atomic_add(msgsz, &ns->msg_bytes);
937 atomic_inc(&ns->msg_hdrs);
938 }
939
940 err = 0;
941 msg = NULL;
942
943out_unlock0:
944 ipc_unlock_object(&msq->q_perm);
945 wake_up_q(&wake_q);
946out_unlock1:
947 rcu_read_unlock();
948 if (msg != NULL)
949 free_msg(msg);
950 return err;
951}
952
953long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
954 int msgflg)
955{
956 long mtype;
957
958 if (get_user(mtype, &msgp->mtype))
959 return -EFAULT;
960 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
961}
962
963SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
964 int, msgflg)
965{
966 return ksys_msgsnd(msqid, msgp, msgsz, msgflg);
967}
968
969#ifdef CONFIG_COMPAT
970
971struct compat_msgbuf {
972 compat_long_t mtype;
973 char mtext[1];
974};
975
976long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
977 compat_ssize_t msgsz, int msgflg)
978{
979 struct compat_msgbuf __user *up = compat_ptr(msgp);
980 compat_long_t mtype;
981
982 if (get_user(mtype, &up->mtype))
983 return -EFAULT;
984 return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg);
985}
986
987COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
988 compat_ssize_t, msgsz, int, msgflg)
989{
990 return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg);
991}
992#endif
993
994static inline int convert_mode(long *msgtyp, int msgflg)
995{
996 if (msgflg & MSG_COPY)
997 return SEARCH_NUMBER;
998 /*
999 * find message of correct type.
1000 * msgtyp = 0 => get first.
1001 * msgtyp > 0 => get first message of matching type.
1002 * msgtyp < 0 => get message with least type must be < abs(msgtype).
1003 */
1004 if (*msgtyp == 0)
1005 return SEARCH_ANY;
1006 if (*msgtyp < 0) {
1007 if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */
1008 *msgtyp = LONG_MAX;
1009 else
1010 *msgtyp = -*msgtyp;
1011 return SEARCH_LESSEQUAL;
1012 }
1013 if (msgflg & MSG_EXCEPT)
1014 return SEARCH_NOTEQUAL;
1015 return SEARCH_EQUAL;
1016}
1017
1018static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
1019{
1020 struct msgbuf __user *msgp = dest;
1021 size_t msgsz;
1022
1023 if (put_user(msg->m_type, &msgp->mtype))
1024 return -EFAULT;
1025
1026 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
1027 if (store_msg(msgp->mtext, msg, msgsz))
1028 return -EFAULT;
1029 return msgsz;
1030}
1031
1032#ifdef CONFIG_CHECKPOINT_RESTORE
1033/*
1034 * This function creates new kernel message structure, large enough to store
1035 * bufsz message bytes.
1036 */
1037static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
1038{
1039 struct msg_msg *copy;
1040
1041 /*
1042 * Create dummy message to copy real message to.
1043 */
1044 copy = load_msg(buf, bufsz);
1045 if (!IS_ERR(copy))
1046 copy->m_ts = bufsz;
1047 return copy;
1048}
1049
1050static inline void free_copy(struct msg_msg *copy)
1051{
1052 if (copy)
1053 free_msg(copy);
1054}
1055#else
1056static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
1057{
1058 return ERR_PTR(-ENOSYS);
1059}
1060
1061static inline void free_copy(struct msg_msg *copy)
1062{
1063}
1064#endif
1065
1066static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
1067{
1068 struct msg_msg *msg, *found = NULL;
1069 long count = 0;
1070
1071 list_for_each_entry(msg, &msq->q_messages, m_list) {
1072 if (testmsg(msg, *msgtyp, mode) &&
1073 !security_msg_queue_msgrcv(&msq->q_perm, msg, current,
1074 *msgtyp, mode)) {
1075 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
1076 *msgtyp = msg->m_type - 1;
1077 found = msg;
1078 } else if (mode == SEARCH_NUMBER) {
1079 if (*msgtyp == count)
1080 return msg;
1081 } else
1082 return msg;
1083 count++;
1084 }
1085 }
1086
1087 return found ?: ERR_PTR(-EAGAIN);
1088}
1089
1090static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg,
1091 long (*msg_handler)(void __user *, struct msg_msg *, size_t))
1092{
1093 int mode;
1094 struct msg_queue *msq;
1095 struct ipc_namespace *ns;
1096 struct msg_msg *msg, *copy = NULL;
1097 DEFINE_WAKE_Q(wake_q);
1098
1099 ns = current->nsproxy->ipc_ns;
1100
1101 if (msqid < 0 || (long) bufsz < 0)
1102 return -EINVAL;
1103
1104 if (msgflg & MSG_COPY) {
1105 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
1106 return -EINVAL;
1107 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
1108 if (IS_ERR(copy))
1109 return PTR_ERR(copy);
1110 }
1111 mode = convert_mode(&msgtyp, msgflg);
1112
1113 rcu_read_lock();
1114 msq = msq_obtain_object_check(ns, msqid);
1115 if (IS_ERR(msq)) {
1116 rcu_read_unlock();
1117 free_copy(copy);
1118 return PTR_ERR(msq);
1119 }
1120
1121 for (;;) {
1122 struct msg_receiver msr_d;
1123
1124 msg = ERR_PTR(-EACCES);
1125 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
1126 goto out_unlock1;
1127
1128 ipc_lock_object(&msq->q_perm);
1129
1130 /* raced with RMID? */
1131 if (!ipc_valid_object(&msq->q_perm)) {
1132 msg = ERR_PTR(-EIDRM);
1133 goto out_unlock0;
1134 }
1135
1136 msg = find_msg(msq, &msgtyp, mode);
1137 if (!IS_ERR(msg)) {
1138 /*
1139 * Found a suitable message.
1140 * Unlink it from the queue.
1141 */
1142 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
1143 msg = ERR_PTR(-E2BIG);
1144 goto out_unlock0;
1145 }
1146 /*
1147 * If we are copying, then do not unlink message and do
1148 * not update queue parameters.
1149 */
1150 if (msgflg & MSG_COPY) {
1151 msg = copy_msg(msg, copy);
1152 goto out_unlock0;
1153 }
1154
1155 list_del(&msg->m_list);
1156 msq->q_qnum--;
1157 msq->q_rtime = ktime_get_real_seconds();
1158 ipc_update_pid(&msq->q_lrpid, task_tgid(current));
1159 msq->q_cbytes -= msg->m_ts;
1160 atomic_sub(msg->m_ts, &ns->msg_bytes);
1161 atomic_dec(&ns->msg_hdrs);
1162 ss_wakeup(msq, &wake_q, false);
1163
1164 goto out_unlock0;
1165 }
1166
1167 /* No message waiting. Wait for a message */
1168 if (msgflg & IPC_NOWAIT) {
1169 msg = ERR_PTR(-ENOMSG);
1170 goto out_unlock0;
1171 }
1172
1173 list_add_tail(&msr_d.r_list, &msq->q_receivers);
1174 msr_d.r_tsk = current;
1175 msr_d.r_msgtype = msgtyp;
1176 msr_d.r_mode = mode;
1177 if (msgflg & MSG_NOERROR)
1178 msr_d.r_maxsize = INT_MAX;
1179 else
1180 msr_d.r_maxsize = bufsz;
1181
1182 /* memory barrier not require due to ipc_lock_object() */
1183 WRITE_ONCE(msr_d.r_msg, ERR_PTR(-EAGAIN));
1184
1185 /* memory barrier not required, we own ipc_lock_object() */
1186 __set_current_state(TASK_INTERRUPTIBLE);
1187
1188 ipc_unlock_object(&msq->q_perm);
1189 rcu_read_unlock();
1190 schedule();
1191
1192 /*
1193 * Lockless receive, part 1:
1194 * We don't hold a reference to the queue and getting a
1195 * reference would defeat the idea of a lockless operation,
1196 * thus the code relies on rcu to guarantee the existence of
1197 * msq:
1198 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
1199 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
1200 */
1201 rcu_read_lock();
1202
1203 /*
1204 * Lockless receive, part 2:
1205 * The work in pipelined_send() and expunge_all():
1206 * - Set pointer to message
1207 * - Queue the receiver task for later wakeup
1208 * - Wake up the process after the lock is dropped.
1209 *
1210 * Should the process wake up before this wakeup (due to a
1211 * signal) it will either see the message and continue ...
1212 */
1213 msg = READ_ONCE(msr_d.r_msg);
1214 if (msg != ERR_PTR(-EAGAIN)) {
1215 /* see MSG_BARRIER for purpose/pairing */
1216 smp_acquire__after_ctrl_dep();
1217
1218 goto out_unlock1;
1219 }
1220
1221 /*
1222 * ... or see -EAGAIN, acquire the lock to check the message
1223 * again.
1224 */
1225 ipc_lock_object(&msq->q_perm);
1226
1227 msg = READ_ONCE(msr_d.r_msg);
1228 if (msg != ERR_PTR(-EAGAIN))
1229 goto out_unlock0;
1230
1231 list_del(&msr_d.r_list);
1232 if (signal_pending(current)) {
1233 msg = ERR_PTR(-ERESTARTNOHAND);
1234 goto out_unlock0;
1235 }
1236
1237 ipc_unlock_object(&msq->q_perm);
1238 }
1239
1240out_unlock0:
1241 ipc_unlock_object(&msq->q_perm);
1242 wake_up_q(&wake_q);
1243out_unlock1:
1244 rcu_read_unlock();
1245 if (IS_ERR(msg)) {
1246 free_copy(copy);
1247 return PTR_ERR(msg);
1248 }
1249
1250 bufsz = msg_handler(buf, msg, bufsz);
1251 free_msg(msg);
1252
1253 return bufsz;
1254}
1255
1256long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
1257 long msgtyp, int msgflg)
1258{
1259 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
1260}
1261
1262SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
1263 long, msgtyp, int, msgflg)
1264{
1265 return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1266}
1267
1268#ifdef CONFIG_COMPAT
1269static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
1270{
1271 struct compat_msgbuf __user *msgp = dest;
1272 size_t msgsz;
1273
1274 if (put_user(msg->m_type, &msgp->mtype))
1275 return -EFAULT;
1276
1277 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
1278 if (store_msg(msgp->mtext, msg, msgsz))
1279 return -EFAULT;
1280 return msgsz;
1281}
1282
1283long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
1284 compat_long_t msgtyp, int msgflg)
1285{
1286 return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp,
1287 msgflg, compat_do_msg_fill);
1288}
1289
1290COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
1291 compat_ssize_t, msgsz, compat_long_t, msgtyp,
1292 int, msgflg)
1293{
1294 return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1295}
1296#endif
1297
1298void msg_init_ns(struct ipc_namespace *ns)
1299{
1300 ns->msg_ctlmax = MSGMAX;
1301 ns->msg_ctlmnb = MSGMNB;
1302 ns->msg_ctlmni = MSGMNI;
1303
1304 atomic_set(&ns->msg_bytes, 0);
1305 atomic_set(&ns->msg_hdrs, 0);
1306 ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
1307}
1308
1309#ifdef CONFIG_IPC_NS
1310void msg_exit_ns(struct ipc_namespace *ns)
1311{
1312 free_ipcs(ns, &msg_ids(ns), freeque);
1313 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
1314 rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht);
1315}
1316#endif
1317
1318#ifdef CONFIG_PROC_FS
1319static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
1320{
1321 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1322 struct user_namespace *user_ns = seq_user_ns(s);
1323 struct kern_ipc_perm *ipcp = it;
1324 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
1325
1326 seq_printf(s,
1327 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n",
1328 msq->q_perm.key,
1329 msq->q_perm.id,
1330 msq->q_perm.mode,
1331 msq->q_cbytes,
1332 msq->q_qnum,
1333 pid_nr_ns(msq->q_lspid, pid_ns),
1334 pid_nr_ns(msq->q_lrpid, pid_ns),
1335 from_kuid_munged(user_ns, msq->q_perm.uid),
1336 from_kgid_munged(user_ns, msq->q_perm.gid),
1337 from_kuid_munged(user_ns, msq->q_perm.cuid),
1338 from_kgid_munged(user_ns, msq->q_perm.cgid),
1339 msq->q_stime,
1340 msq->q_rtime,
1341 msq->q_ctime);
1342
1343 return 0;
1344}
1345#endif
1346
1347void __init msg_init(void)
1348{
1349 msg_init_ns(&init_ipc_ns);
1350
1351 ipc_init_proc_interface("sysvipc/msg",
1352 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
1353 IPC_MSG_IDS, sysvipc_msg_proc_show);
1354}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/ipc/msg.c
4 * Copyright (C) 1992 Krishna Balasubramanian
5 *
6 * Removed all the remaining kerneld mess
7 * Catch the -EFAULT stuff properly
8 * Use GFP_KERNEL for messages as in 1.2
9 * Fixed up the unchecked user space derefs
10 * Copyright (C) 1998 Alan Cox & Andi Kleen
11 *
12 * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
13 *
14 * mostly rewritten, threaded and wake-one semantics added
15 * MSGMAX limit removed, sysctl's added
16 * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
17 *
18 * support for audit of ipc object properties and permission changes
19 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
20 *
21 * namespaces support
22 * OpenVZ, SWsoft Inc.
23 * Pavel Emelianov <xemul@openvz.org>
24 */
25
26#include <linux/capability.h>
27#include <linux/msg.h>
28#include <linux/spinlock.h>
29#include <linux/init.h>
30#include <linux/mm.h>
31#include <linux/proc_fs.h>
32#include <linux/list.h>
33#include <linux/security.h>
34#include <linux/sched/wake_q.h>
35#include <linux/syscalls.h>
36#include <linux/audit.h>
37#include <linux/seq_file.h>
38#include <linux/rwsem.h>
39#include <linux/nsproxy.h>
40#include <linux/ipc_namespace.h>
41
42#include <asm/current.h>
43#include <linux/uaccess.h>
44#include "util.h"
45
46/* one msq_queue structure for each present queue on the system */
47struct msg_queue {
48 struct kern_ipc_perm q_perm;
49 time64_t q_stime; /* last msgsnd time */
50 time64_t q_rtime; /* last msgrcv time */
51 time64_t q_ctime; /* last change time */
52 unsigned long q_cbytes; /* current number of bytes on queue */
53 unsigned long q_qnum; /* number of messages in queue */
54 unsigned long q_qbytes; /* max number of bytes on queue */
55 struct pid *q_lspid; /* pid of last msgsnd */
56 struct pid *q_lrpid; /* last receive pid */
57
58 struct list_head q_messages;
59 struct list_head q_receivers;
60 struct list_head q_senders;
61} __randomize_layout;
62
63/* one msg_receiver structure for each sleeping receiver */
64struct msg_receiver {
65 struct list_head r_list;
66 struct task_struct *r_tsk;
67
68 int r_mode;
69 long r_msgtype;
70 long r_maxsize;
71
72 struct msg_msg *r_msg;
73};
74
75/* one msg_sender for each sleeping sender */
76struct msg_sender {
77 struct list_head list;
78 struct task_struct *tsk;
79 size_t msgsz;
80};
81
82#define SEARCH_ANY 1
83#define SEARCH_EQUAL 2
84#define SEARCH_NOTEQUAL 3
85#define SEARCH_LESSEQUAL 4
86#define SEARCH_NUMBER 5
87
88#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
89
90static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
91{
92 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&msg_ids(ns), id);
93
94 if (IS_ERR(ipcp))
95 return ERR_CAST(ipcp);
96
97 return container_of(ipcp, struct msg_queue, q_perm);
98}
99
100static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
101 int id)
102{
103 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
104
105 if (IS_ERR(ipcp))
106 return ERR_CAST(ipcp);
107
108 return container_of(ipcp, struct msg_queue, q_perm);
109}
110
111static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
112{
113 ipc_rmid(&msg_ids(ns), &s->q_perm);
114}
115
116static void msg_rcu_free(struct rcu_head *head)
117{
118 struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
119 struct msg_queue *msq = container_of(p, struct msg_queue, q_perm);
120
121 security_msg_queue_free(&msq->q_perm);
122 kvfree(msq);
123}
124
125/**
126 * newque - Create a new msg queue
127 * @ns: namespace
128 * @params: ptr to the structure that contains the key and msgflg
129 *
130 * Called with msg_ids.rwsem held (writer)
131 */
132static int newque(struct ipc_namespace *ns, struct ipc_params *params)
133{
134 struct msg_queue *msq;
135 int retval;
136 key_t key = params->key;
137 int msgflg = params->flg;
138
139 msq = kvmalloc(sizeof(*msq), GFP_KERNEL);
140 if (unlikely(!msq))
141 return -ENOMEM;
142
143 msq->q_perm.mode = msgflg & S_IRWXUGO;
144 msq->q_perm.key = key;
145
146 msq->q_perm.security = NULL;
147 retval = security_msg_queue_alloc(&msq->q_perm);
148 if (retval) {
149 kvfree(msq);
150 return retval;
151 }
152
153 msq->q_stime = msq->q_rtime = 0;
154 msq->q_ctime = ktime_get_real_seconds();
155 msq->q_cbytes = msq->q_qnum = 0;
156 msq->q_qbytes = ns->msg_ctlmnb;
157 msq->q_lspid = msq->q_lrpid = NULL;
158 INIT_LIST_HEAD(&msq->q_messages);
159 INIT_LIST_HEAD(&msq->q_receivers);
160 INIT_LIST_HEAD(&msq->q_senders);
161
162 /* ipc_addid() locks msq upon success. */
163 retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
164 if (retval < 0) {
165 call_rcu(&msq->q_perm.rcu, msg_rcu_free);
166 return retval;
167 }
168
169 ipc_unlock_object(&msq->q_perm);
170 rcu_read_unlock();
171
172 return msq->q_perm.id;
173}
174
175static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz)
176{
177 return msgsz + msq->q_cbytes <= msq->q_qbytes &&
178 1 + msq->q_qnum <= msq->q_qbytes;
179}
180
181static inline void ss_add(struct msg_queue *msq,
182 struct msg_sender *mss, size_t msgsz)
183{
184 mss->tsk = current;
185 mss->msgsz = msgsz;
186 __set_current_state(TASK_INTERRUPTIBLE);
187 list_add_tail(&mss->list, &msq->q_senders);
188}
189
190static inline void ss_del(struct msg_sender *mss)
191{
192 if (mss->list.next)
193 list_del(&mss->list);
194}
195
196static void ss_wakeup(struct msg_queue *msq,
197 struct wake_q_head *wake_q, bool kill)
198{
199 struct msg_sender *mss, *t;
200 struct task_struct *stop_tsk = NULL;
201 struct list_head *h = &msq->q_senders;
202
203 list_for_each_entry_safe(mss, t, h, list) {
204 if (kill)
205 mss->list.next = NULL;
206
207 /*
208 * Stop at the first task we don't wakeup,
209 * we've already iterated the original
210 * sender queue.
211 */
212 else if (stop_tsk == mss->tsk)
213 break;
214 /*
215 * We are not in an EIDRM scenario here, therefore
216 * verify that we really need to wakeup the task.
217 * To maintain current semantics and wakeup order,
218 * move the sender to the tail on behalf of the
219 * blocked task.
220 */
221 else if (!msg_fits_inqueue(msq, mss->msgsz)) {
222 if (!stop_tsk)
223 stop_tsk = mss->tsk;
224
225 list_move_tail(&mss->list, &msq->q_senders);
226 continue;
227 }
228
229 wake_q_add(wake_q, mss->tsk);
230 }
231}
232
233static void expunge_all(struct msg_queue *msq, int res,
234 struct wake_q_head *wake_q)
235{
236 struct msg_receiver *msr, *t;
237
238 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
239 wake_q_add(wake_q, msr->r_tsk);
240 WRITE_ONCE(msr->r_msg, ERR_PTR(res));
241 }
242}
243
244/*
245 * freeque() wakes up waiters on the sender and receiver waiting queue,
246 * removes the message queue from message queue ID IDR, and cleans up all the
247 * messages associated with this queue.
248 *
249 * msg_ids.rwsem (writer) and the spinlock for this message queue are held
250 * before freeque() is called. msg_ids.rwsem remains locked on exit.
251 */
252static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
253{
254 struct msg_msg *msg, *t;
255 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
256 DEFINE_WAKE_Q(wake_q);
257
258 expunge_all(msq, -EIDRM, &wake_q);
259 ss_wakeup(msq, &wake_q, true);
260 msg_rmid(ns, msq);
261 ipc_unlock_object(&msq->q_perm);
262 wake_up_q(&wake_q);
263 rcu_read_unlock();
264
265 list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
266 atomic_dec(&ns->msg_hdrs);
267 free_msg(msg);
268 }
269 atomic_sub(msq->q_cbytes, &ns->msg_bytes);
270 ipc_update_pid(&msq->q_lspid, NULL);
271 ipc_update_pid(&msq->q_lrpid, NULL);
272 ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
273}
274
275long ksys_msgget(key_t key, int msgflg)
276{
277 struct ipc_namespace *ns;
278 static const struct ipc_ops msg_ops = {
279 .getnew = newque,
280 .associate = security_msg_queue_associate,
281 };
282 struct ipc_params msg_params;
283
284 ns = current->nsproxy->ipc_ns;
285
286 msg_params.key = key;
287 msg_params.flg = msgflg;
288
289 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
290}
291
292SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
293{
294 return ksys_msgget(key, msgflg);
295}
296
297static inline unsigned long
298copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
299{
300 switch (version) {
301 case IPC_64:
302 return copy_to_user(buf, in, sizeof(*in));
303 case IPC_OLD:
304 {
305 struct msqid_ds out;
306
307 memset(&out, 0, sizeof(out));
308
309 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
310
311 out.msg_stime = in->msg_stime;
312 out.msg_rtime = in->msg_rtime;
313 out.msg_ctime = in->msg_ctime;
314
315 if (in->msg_cbytes > USHRT_MAX)
316 out.msg_cbytes = USHRT_MAX;
317 else
318 out.msg_cbytes = in->msg_cbytes;
319 out.msg_lcbytes = in->msg_cbytes;
320
321 if (in->msg_qnum > USHRT_MAX)
322 out.msg_qnum = USHRT_MAX;
323 else
324 out.msg_qnum = in->msg_qnum;
325
326 if (in->msg_qbytes > USHRT_MAX)
327 out.msg_qbytes = USHRT_MAX;
328 else
329 out.msg_qbytes = in->msg_qbytes;
330 out.msg_lqbytes = in->msg_qbytes;
331
332 out.msg_lspid = in->msg_lspid;
333 out.msg_lrpid = in->msg_lrpid;
334
335 return copy_to_user(buf, &out, sizeof(out));
336 }
337 default:
338 return -EINVAL;
339 }
340}
341
342static inline unsigned long
343copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
344{
345 switch (version) {
346 case IPC_64:
347 if (copy_from_user(out, buf, sizeof(*out)))
348 return -EFAULT;
349 return 0;
350 case IPC_OLD:
351 {
352 struct msqid_ds tbuf_old;
353
354 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
355 return -EFAULT;
356
357 out->msg_perm.uid = tbuf_old.msg_perm.uid;
358 out->msg_perm.gid = tbuf_old.msg_perm.gid;
359 out->msg_perm.mode = tbuf_old.msg_perm.mode;
360
361 if (tbuf_old.msg_qbytes == 0)
362 out->msg_qbytes = tbuf_old.msg_lqbytes;
363 else
364 out->msg_qbytes = tbuf_old.msg_qbytes;
365
366 return 0;
367 }
368 default:
369 return -EINVAL;
370 }
371}
372
373/*
374 * This function handles some msgctl commands which require the rwsem
375 * to be held in write mode.
376 * NOTE: no locks must be held, the rwsem is taken inside this function.
377 */
378static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
379 struct msqid64_ds *msqid64)
380{
381 struct kern_ipc_perm *ipcp;
382 struct msg_queue *msq;
383 int err;
384
385 down_write(&msg_ids(ns).rwsem);
386 rcu_read_lock();
387
388 ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
389 &msqid64->msg_perm, msqid64->msg_qbytes);
390 if (IS_ERR(ipcp)) {
391 err = PTR_ERR(ipcp);
392 goto out_unlock1;
393 }
394
395 msq = container_of(ipcp, struct msg_queue, q_perm);
396
397 err = security_msg_queue_msgctl(&msq->q_perm, cmd);
398 if (err)
399 goto out_unlock1;
400
401 switch (cmd) {
402 case IPC_RMID:
403 ipc_lock_object(&msq->q_perm);
404 /* freeque unlocks the ipc object and rcu */
405 freeque(ns, ipcp);
406 goto out_up;
407 case IPC_SET:
408 {
409 DEFINE_WAKE_Q(wake_q);
410
411 if (msqid64->msg_qbytes > ns->msg_ctlmnb &&
412 !capable(CAP_SYS_RESOURCE)) {
413 err = -EPERM;
414 goto out_unlock1;
415 }
416
417 ipc_lock_object(&msq->q_perm);
418 err = ipc_update_perm(&msqid64->msg_perm, ipcp);
419 if (err)
420 goto out_unlock0;
421
422 msq->q_qbytes = msqid64->msg_qbytes;
423
424 msq->q_ctime = ktime_get_real_seconds();
425 /*
426 * Sleeping receivers might be excluded by
427 * stricter permissions.
428 */
429 expunge_all(msq, -EAGAIN, &wake_q);
430 /*
431 * Sleeping senders might be able to send
432 * due to a larger queue size.
433 */
434 ss_wakeup(msq, &wake_q, false);
435 ipc_unlock_object(&msq->q_perm);
436 wake_up_q(&wake_q);
437
438 goto out_unlock1;
439 }
440 default:
441 err = -EINVAL;
442 goto out_unlock1;
443 }
444
445out_unlock0:
446 ipc_unlock_object(&msq->q_perm);
447out_unlock1:
448 rcu_read_unlock();
449out_up:
450 up_write(&msg_ids(ns).rwsem);
451 return err;
452}
453
454static int msgctl_info(struct ipc_namespace *ns, int msqid,
455 int cmd, struct msginfo *msginfo)
456{
457 int err;
458 int max_id;
459
460 /*
461 * We must not return kernel stack data.
462 * due to padding, it's not enough
463 * to set all member fields.
464 */
465 err = security_msg_queue_msgctl(NULL, cmd);
466 if (err)
467 return err;
468
469 memset(msginfo, 0, sizeof(*msginfo));
470 msginfo->msgmni = ns->msg_ctlmni;
471 msginfo->msgmax = ns->msg_ctlmax;
472 msginfo->msgmnb = ns->msg_ctlmnb;
473 msginfo->msgssz = MSGSSZ;
474 msginfo->msgseg = MSGSEG;
475 down_read(&msg_ids(ns).rwsem);
476 if (cmd == MSG_INFO) {
477 msginfo->msgpool = msg_ids(ns).in_use;
478 msginfo->msgmap = atomic_read(&ns->msg_hdrs);
479 msginfo->msgtql = atomic_read(&ns->msg_bytes);
480 } else {
481 msginfo->msgmap = MSGMAP;
482 msginfo->msgpool = MSGPOOL;
483 msginfo->msgtql = MSGTQL;
484 }
485 max_id = ipc_get_maxid(&msg_ids(ns));
486 up_read(&msg_ids(ns).rwsem);
487 return (max_id < 0) ? 0 : max_id;
488}
489
490static int msgctl_stat(struct ipc_namespace *ns, int msqid,
491 int cmd, struct msqid64_ds *p)
492{
493 struct msg_queue *msq;
494 int id = 0;
495 int err;
496
497 memset(p, 0, sizeof(*p));
498
499 rcu_read_lock();
500 if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) {
501 msq = msq_obtain_object(ns, msqid);
502 if (IS_ERR(msq)) {
503 err = PTR_ERR(msq);
504 goto out_unlock;
505 }
506 id = msq->q_perm.id;
507 } else { /* IPC_STAT */
508 msq = msq_obtain_object_check(ns, msqid);
509 if (IS_ERR(msq)) {
510 err = PTR_ERR(msq);
511 goto out_unlock;
512 }
513 }
514
515 /* see comment for SHM_STAT_ANY */
516 if (cmd == MSG_STAT_ANY)
517 audit_ipc_obj(&msq->q_perm);
518 else {
519 err = -EACCES;
520 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
521 goto out_unlock;
522 }
523
524 err = security_msg_queue_msgctl(&msq->q_perm, cmd);
525 if (err)
526 goto out_unlock;
527
528 ipc_lock_object(&msq->q_perm);
529
530 if (!ipc_valid_object(&msq->q_perm)) {
531 ipc_unlock_object(&msq->q_perm);
532 err = -EIDRM;
533 goto out_unlock;
534 }
535
536 kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm);
537 p->msg_stime = msq->q_stime;
538 p->msg_rtime = msq->q_rtime;
539 p->msg_ctime = msq->q_ctime;
540 p->msg_cbytes = msq->q_cbytes;
541 p->msg_qnum = msq->q_qnum;
542 p->msg_qbytes = msq->q_qbytes;
543 p->msg_lspid = pid_vnr(msq->q_lspid);
544 p->msg_lrpid = pid_vnr(msq->q_lrpid);
545
546 ipc_unlock_object(&msq->q_perm);
547 rcu_read_unlock();
548 return id;
549
550out_unlock:
551 rcu_read_unlock();
552 return err;
553}
554
555long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
556{
557 int version;
558 struct ipc_namespace *ns;
559 struct msqid64_ds msqid64;
560 int err;
561
562 if (msqid < 0 || cmd < 0)
563 return -EINVAL;
564
565 version = ipc_parse_version(&cmd);
566 ns = current->nsproxy->ipc_ns;
567
568 switch (cmd) {
569 case IPC_INFO:
570 case MSG_INFO: {
571 struct msginfo msginfo;
572 err = msgctl_info(ns, msqid, cmd, &msginfo);
573 if (err < 0)
574 return err;
575 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
576 err = -EFAULT;
577 return err;
578 }
579 case MSG_STAT: /* msqid is an index rather than a msg queue id */
580 case MSG_STAT_ANY:
581 case IPC_STAT:
582 err = msgctl_stat(ns, msqid, cmd, &msqid64);
583 if (err < 0)
584 return err;
585 if (copy_msqid_to_user(buf, &msqid64, version))
586 err = -EFAULT;
587 return err;
588 case IPC_SET:
589 if (copy_msqid_from_user(&msqid64, buf, version))
590 return -EFAULT;
591 /* fallthru */
592 case IPC_RMID:
593 return msgctl_down(ns, msqid, cmd, &msqid64);
594 default:
595 return -EINVAL;
596 }
597}
598
599SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
600{
601 return ksys_msgctl(msqid, cmd, buf);
602}
603
604#ifdef CONFIG_COMPAT
605
606struct compat_msqid_ds {
607 struct compat_ipc_perm msg_perm;
608 compat_uptr_t msg_first;
609 compat_uptr_t msg_last;
610 compat_time_t msg_stime;
611 compat_time_t msg_rtime;
612 compat_time_t msg_ctime;
613 compat_ulong_t msg_lcbytes;
614 compat_ulong_t msg_lqbytes;
615 unsigned short msg_cbytes;
616 unsigned short msg_qnum;
617 unsigned short msg_qbytes;
618 compat_ipc_pid_t msg_lspid;
619 compat_ipc_pid_t msg_lrpid;
620};
621
622static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf,
623 int version)
624{
625 memset(out, 0, sizeof(*out));
626 if (version == IPC_64) {
627 struct compat_msqid64_ds __user *p = buf;
628 if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm))
629 return -EFAULT;
630 if (get_user(out->msg_qbytes, &p->msg_qbytes))
631 return -EFAULT;
632 } else {
633 struct compat_msqid_ds __user *p = buf;
634 if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm))
635 return -EFAULT;
636 if (get_user(out->msg_qbytes, &p->msg_qbytes))
637 return -EFAULT;
638 }
639 return 0;
640}
641
642static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in,
643 int version)
644{
645 if (version == IPC_64) {
646 struct compat_msqid64_ds v;
647 memset(&v, 0, sizeof(v));
648 to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm);
649 v.msg_stime = in->msg_stime;
650 v.msg_rtime = in->msg_rtime;
651 v.msg_ctime = in->msg_ctime;
652 v.msg_cbytes = in->msg_cbytes;
653 v.msg_qnum = in->msg_qnum;
654 v.msg_qbytes = in->msg_qbytes;
655 v.msg_lspid = in->msg_lspid;
656 v.msg_lrpid = in->msg_lrpid;
657 return copy_to_user(buf, &v, sizeof(v));
658 } else {
659 struct compat_msqid_ds v;
660 memset(&v, 0, sizeof(v));
661 to_compat_ipc_perm(&v.msg_perm, &in->msg_perm);
662 v.msg_stime = in->msg_stime;
663 v.msg_rtime = in->msg_rtime;
664 v.msg_ctime = in->msg_ctime;
665 v.msg_cbytes = in->msg_cbytes;
666 v.msg_qnum = in->msg_qnum;
667 v.msg_qbytes = in->msg_qbytes;
668 v.msg_lspid = in->msg_lspid;
669 v.msg_lrpid = in->msg_lrpid;
670 return copy_to_user(buf, &v, sizeof(v));
671 }
672}
673
674long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr)
675{
676 struct ipc_namespace *ns;
677 int err;
678 struct msqid64_ds msqid64;
679 int version = compat_ipc_parse_version(&cmd);
680
681 ns = current->nsproxy->ipc_ns;
682
683 if (msqid < 0 || cmd < 0)
684 return -EINVAL;
685
686 switch (cmd & (~IPC_64)) {
687 case IPC_INFO:
688 case MSG_INFO: {
689 struct msginfo msginfo;
690 err = msgctl_info(ns, msqid, cmd, &msginfo);
691 if (err < 0)
692 return err;
693 if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo)))
694 err = -EFAULT;
695 return err;
696 }
697 case IPC_STAT:
698 case MSG_STAT:
699 case MSG_STAT_ANY:
700 err = msgctl_stat(ns, msqid, cmd, &msqid64);
701 if (err < 0)
702 return err;
703 if (copy_compat_msqid_to_user(uptr, &msqid64, version))
704 err = -EFAULT;
705 return err;
706 case IPC_SET:
707 if (copy_compat_msqid_from_user(&msqid64, uptr, version))
708 return -EFAULT;
709 /* fallthru */
710 case IPC_RMID:
711 return msgctl_down(ns, msqid, cmd, &msqid64);
712 default:
713 return -EINVAL;
714 }
715}
716
717COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)
718{
719 return compat_ksys_msgctl(msqid, cmd, uptr);
720}
721#endif
722
723static int testmsg(struct msg_msg *msg, long type, int mode)
724{
725 switch (mode) {
726 case SEARCH_ANY:
727 case SEARCH_NUMBER:
728 return 1;
729 case SEARCH_LESSEQUAL:
730 if (msg->m_type <= type)
731 return 1;
732 break;
733 case SEARCH_EQUAL:
734 if (msg->m_type == type)
735 return 1;
736 break;
737 case SEARCH_NOTEQUAL:
738 if (msg->m_type != type)
739 return 1;
740 break;
741 }
742 return 0;
743}
744
745static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg,
746 struct wake_q_head *wake_q)
747{
748 struct msg_receiver *msr, *t;
749
750 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
751 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
752 !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk,
753 msr->r_msgtype, msr->r_mode)) {
754
755 list_del(&msr->r_list);
756 if (msr->r_maxsize < msg->m_ts) {
757 wake_q_add(wake_q, msr->r_tsk);
758 WRITE_ONCE(msr->r_msg, ERR_PTR(-E2BIG));
759 } else {
760 ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk));
761 msq->q_rtime = get_seconds();
762
763 wake_q_add(wake_q, msr->r_tsk);
764 WRITE_ONCE(msr->r_msg, msg);
765 return 1;
766 }
767 }
768 }
769
770 return 0;
771}
772
773static long do_msgsnd(int msqid, long mtype, void __user *mtext,
774 size_t msgsz, int msgflg)
775{
776 struct msg_queue *msq;
777 struct msg_msg *msg;
778 int err;
779 struct ipc_namespace *ns;
780 DEFINE_WAKE_Q(wake_q);
781
782 ns = current->nsproxy->ipc_ns;
783
784 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
785 return -EINVAL;
786 if (mtype < 1)
787 return -EINVAL;
788
789 msg = load_msg(mtext, msgsz);
790 if (IS_ERR(msg))
791 return PTR_ERR(msg);
792
793 msg->m_type = mtype;
794 msg->m_ts = msgsz;
795
796 rcu_read_lock();
797 msq = msq_obtain_object_check(ns, msqid);
798 if (IS_ERR(msq)) {
799 err = PTR_ERR(msq);
800 goto out_unlock1;
801 }
802
803 ipc_lock_object(&msq->q_perm);
804
805 for (;;) {
806 struct msg_sender s;
807
808 err = -EACCES;
809 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
810 goto out_unlock0;
811
812 /* raced with RMID? */
813 if (!ipc_valid_object(&msq->q_perm)) {
814 err = -EIDRM;
815 goto out_unlock0;
816 }
817
818 err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg);
819 if (err)
820 goto out_unlock0;
821
822 if (msg_fits_inqueue(msq, msgsz))
823 break;
824
825 /* queue full, wait: */
826 if (msgflg & IPC_NOWAIT) {
827 err = -EAGAIN;
828 goto out_unlock0;
829 }
830
831 /* enqueue the sender and prepare to block */
832 ss_add(msq, &s, msgsz);
833
834 if (!ipc_rcu_getref(&msq->q_perm)) {
835 err = -EIDRM;
836 goto out_unlock0;
837 }
838
839 ipc_unlock_object(&msq->q_perm);
840 rcu_read_unlock();
841 schedule();
842
843 rcu_read_lock();
844 ipc_lock_object(&msq->q_perm);
845
846 ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
847 /* raced with RMID? */
848 if (!ipc_valid_object(&msq->q_perm)) {
849 err = -EIDRM;
850 goto out_unlock0;
851 }
852 ss_del(&s);
853
854 if (signal_pending(current)) {
855 err = -ERESTARTNOHAND;
856 goto out_unlock0;
857 }
858
859 }
860
861 ipc_update_pid(&msq->q_lspid, task_tgid(current));
862 msq->q_stime = get_seconds();
863
864 if (!pipelined_send(msq, msg, &wake_q)) {
865 /* no one is waiting for this message, enqueue it */
866 list_add_tail(&msg->m_list, &msq->q_messages);
867 msq->q_cbytes += msgsz;
868 msq->q_qnum++;
869 atomic_add(msgsz, &ns->msg_bytes);
870 atomic_inc(&ns->msg_hdrs);
871 }
872
873 err = 0;
874 msg = NULL;
875
876out_unlock0:
877 ipc_unlock_object(&msq->q_perm);
878 wake_up_q(&wake_q);
879out_unlock1:
880 rcu_read_unlock();
881 if (msg != NULL)
882 free_msg(msg);
883 return err;
884}
885
886long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
887 int msgflg)
888{
889 long mtype;
890
891 if (get_user(mtype, &msgp->mtype))
892 return -EFAULT;
893 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
894}
895
896SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
897 int, msgflg)
898{
899 return ksys_msgsnd(msqid, msgp, msgsz, msgflg);
900}
901
902#ifdef CONFIG_COMPAT
903
904struct compat_msgbuf {
905 compat_long_t mtype;
906 char mtext[1];
907};
908
909long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
910 compat_ssize_t msgsz, int msgflg)
911{
912 struct compat_msgbuf __user *up = compat_ptr(msgp);
913 compat_long_t mtype;
914
915 if (get_user(mtype, &up->mtype))
916 return -EFAULT;
917 return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg);
918}
919
920COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
921 compat_ssize_t, msgsz, int, msgflg)
922{
923 return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg);
924}
925#endif
926
927static inline int convert_mode(long *msgtyp, int msgflg)
928{
929 if (msgflg & MSG_COPY)
930 return SEARCH_NUMBER;
931 /*
932 * find message of correct type.
933 * msgtyp = 0 => get first.
934 * msgtyp > 0 => get first message of matching type.
935 * msgtyp < 0 => get message with least type must be < abs(msgtype).
936 */
937 if (*msgtyp == 0)
938 return SEARCH_ANY;
939 if (*msgtyp < 0) {
940 if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */
941 *msgtyp = LONG_MAX;
942 else
943 *msgtyp = -*msgtyp;
944 return SEARCH_LESSEQUAL;
945 }
946 if (msgflg & MSG_EXCEPT)
947 return SEARCH_NOTEQUAL;
948 return SEARCH_EQUAL;
949}
950
951static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
952{
953 struct msgbuf __user *msgp = dest;
954 size_t msgsz;
955
956 if (put_user(msg->m_type, &msgp->mtype))
957 return -EFAULT;
958
959 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
960 if (store_msg(msgp->mtext, msg, msgsz))
961 return -EFAULT;
962 return msgsz;
963}
964
965#ifdef CONFIG_CHECKPOINT_RESTORE
966/*
967 * This function creates new kernel message structure, large enough to store
968 * bufsz message bytes.
969 */
970static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
971{
972 struct msg_msg *copy;
973
974 /*
975 * Create dummy message to copy real message to.
976 */
977 copy = load_msg(buf, bufsz);
978 if (!IS_ERR(copy))
979 copy->m_ts = bufsz;
980 return copy;
981}
982
983static inline void free_copy(struct msg_msg *copy)
984{
985 if (copy)
986 free_msg(copy);
987}
988#else
989static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
990{
991 return ERR_PTR(-ENOSYS);
992}
993
994static inline void free_copy(struct msg_msg *copy)
995{
996}
997#endif
998
999static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
1000{
1001 struct msg_msg *msg, *found = NULL;
1002 long count = 0;
1003
1004 list_for_each_entry(msg, &msq->q_messages, m_list) {
1005 if (testmsg(msg, *msgtyp, mode) &&
1006 !security_msg_queue_msgrcv(&msq->q_perm, msg, current,
1007 *msgtyp, mode)) {
1008 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
1009 *msgtyp = msg->m_type - 1;
1010 found = msg;
1011 } else if (mode == SEARCH_NUMBER) {
1012 if (*msgtyp == count)
1013 return msg;
1014 } else
1015 return msg;
1016 count++;
1017 }
1018 }
1019
1020 return found ?: ERR_PTR(-EAGAIN);
1021}
1022
1023static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg,
1024 long (*msg_handler)(void __user *, struct msg_msg *, size_t))
1025{
1026 int mode;
1027 struct msg_queue *msq;
1028 struct ipc_namespace *ns;
1029 struct msg_msg *msg, *copy = NULL;
1030 DEFINE_WAKE_Q(wake_q);
1031
1032 ns = current->nsproxy->ipc_ns;
1033
1034 if (msqid < 0 || (long) bufsz < 0)
1035 return -EINVAL;
1036
1037 if (msgflg & MSG_COPY) {
1038 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
1039 return -EINVAL;
1040 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
1041 if (IS_ERR(copy))
1042 return PTR_ERR(copy);
1043 }
1044 mode = convert_mode(&msgtyp, msgflg);
1045
1046 rcu_read_lock();
1047 msq = msq_obtain_object_check(ns, msqid);
1048 if (IS_ERR(msq)) {
1049 rcu_read_unlock();
1050 free_copy(copy);
1051 return PTR_ERR(msq);
1052 }
1053
1054 for (;;) {
1055 struct msg_receiver msr_d;
1056
1057 msg = ERR_PTR(-EACCES);
1058 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
1059 goto out_unlock1;
1060
1061 ipc_lock_object(&msq->q_perm);
1062
1063 /* raced with RMID? */
1064 if (!ipc_valid_object(&msq->q_perm)) {
1065 msg = ERR_PTR(-EIDRM);
1066 goto out_unlock0;
1067 }
1068
1069 msg = find_msg(msq, &msgtyp, mode);
1070 if (!IS_ERR(msg)) {
1071 /*
1072 * Found a suitable message.
1073 * Unlink it from the queue.
1074 */
1075 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
1076 msg = ERR_PTR(-E2BIG);
1077 goto out_unlock0;
1078 }
1079 /*
1080 * If we are copying, then do not unlink message and do
1081 * not update queue parameters.
1082 */
1083 if (msgflg & MSG_COPY) {
1084 msg = copy_msg(msg, copy);
1085 goto out_unlock0;
1086 }
1087
1088 list_del(&msg->m_list);
1089 msq->q_qnum--;
1090 msq->q_rtime = get_seconds();
1091 ipc_update_pid(&msq->q_lrpid, task_tgid(current));
1092 msq->q_cbytes -= msg->m_ts;
1093 atomic_sub(msg->m_ts, &ns->msg_bytes);
1094 atomic_dec(&ns->msg_hdrs);
1095 ss_wakeup(msq, &wake_q, false);
1096
1097 goto out_unlock0;
1098 }
1099
1100 /* No message waiting. Wait for a message */
1101 if (msgflg & IPC_NOWAIT) {
1102 msg = ERR_PTR(-ENOMSG);
1103 goto out_unlock0;
1104 }
1105
1106 list_add_tail(&msr_d.r_list, &msq->q_receivers);
1107 msr_d.r_tsk = current;
1108 msr_d.r_msgtype = msgtyp;
1109 msr_d.r_mode = mode;
1110 if (msgflg & MSG_NOERROR)
1111 msr_d.r_maxsize = INT_MAX;
1112 else
1113 msr_d.r_maxsize = bufsz;
1114 msr_d.r_msg = ERR_PTR(-EAGAIN);
1115 __set_current_state(TASK_INTERRUPTIBLE);
1116
1117 ipc_unlock_object(&msq->q_perm);
1118 rcu_read_unlock();
1119 schedule();
1120
1121 /*
1122 * Lockless receive, part 1:
1123 * We don't hold a reference to the queue and getting a
1124 * reference would defeat the idea of a lockless operation,
1125 * thus the code relies on rcu to guarantee the existence of
1126 * msq:
1127 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
1128 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
1129 */
1130 rcu_read_lock();
1131
1132 /*
1133 * Lockless receive, part 2:
1134 * The work in pipelined_send() and expunge_all():
1135 * - Set pointer to message
1136 * - Queue the receiver task for later wakeup
1137 * - Wake up the process after the lock is dropped.
1138 *
1139 * Should the process wake up before this wakeup (due to a
1140 * signal) it will either see the message and continue ...
1141 */
1142 msg = READ_ONCE(msr_d.r_msg);
1143 if (msg != ERR_PTR(-EAGAIN))
1144 goto out_unlock1;
1145
1146 /*
1147 * ... or see -EAGAIN, acquire the lock to check the message
1148 * again.
1149 */
1150 ipc_lock_object(&msq->q_perm);
1151
1152 msg = msr_d.r_msg;
1153 if (msg != ERR_PTR(-EAGAIN))
1154 goto out_unlock0;
1155
1156 list_del(&msr_d.r_list);
1157 if (signal_pending(current)) {
1158 msg = ERR_PTR(-ERESTARTNOHAND);
1159 goto out_unlock0;
1160 }
1161
1162 ipc_unlock_object(&msq->q_perm);
1163 }
1164
1165out_unlock0:
1166 ipc_unlock_object(&msq->q_perm);
1167 wake_up_q(&wake_q);
1168out_unlock1:
1169 rcu_read_unlock();
1170 if (IS_ERR(msg)) {
1171 free_copy(copy);
1172 return PTR_ERR(msg);
1173 }
1174
1175 bufsz = msg_handler(buf, msg, bufsz);
1176 free_msg(msg);
1177
1178 return bufsz;
1179}
1180
1181long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
1182 long msgtyp, int msgflg)
1183{
1184 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
1185}
1186
1187SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
1188 long, msgtyp, int, msgflg)
1189{
1190 return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1191}
1192
1193#ifdef CONFIG_COMPAT
1194static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
1195{
1196 struct compat_msgbuf __user *msgp = dest;
1197 size_t msgsz;
1198
1199 if (put_user(msg->m_type, &msgp->mtype))
1200 return -EFAULT;
1201
1202 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
1203 if (store_msg(msgp->mtext, msg, msgsz))
1204 return -EFAULT;
1205 return msgsz;
1206}
1207
1208long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
1209 compat_long_t msgtyp, int msgflg)
1210{
1211 return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp,
1212 msgflg, compat_do_msg_fill);
1213}
1214
1215COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
1216 compat_ssize_t, msgsz, compat_long_t, msgtyp,
1217 int, msgflg)
1218{
1219 return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1220}
1221#endif
1222
1223int msg_init_ns(struct ipc_namespace *ns)
1224{
1225 ns->msg_ctlmax = MSGMAX;
1226 ns->msg_ctlmnb = MSGMNB;
1227 ns->msg_ctlmni = MSGMNI;
1228
1229 atomic_set(&ns->msg_bytes, 0);
1230 atomic_set(&ns->msg_hdrs, 0);
1231 return ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
1232}
1233
1234#ifdef CONFIG_IPC_NS
1235void msg_exit_ns(struct ipc_namespace *ns)
1236{
1237 free_ipcs(ns, &msg_ids(ns), freeque);
1238 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
1239 rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht);
1240}
1241#endif
1242
1243#ifdef CONFIG_PROC_FS
1244static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
1245{
1246 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1247 struct user_namespace *user_ns = seq_user_ns(s);
1248 struct kern_ipc_perm *ipcp = it;
1249 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
1250
1251 seq_printf(s,
1252 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n",
1253 msq->q_perm.key,
1254 msq->q_perm.id,
1255 msq->q_perm.mode,
1256 msq->q_cbytes,
1257 msq->q_qnum,
1258 pid_nr_ns(msq->q_lspid, pid_ns),
1259 pid_nr_ns(msq->q_lrpid, pid_ns),
1260 from_kuid_munged(user_ns, msq->q_perm.uid),
1261 from_kgid_munged(user_ns, msq->q_perm.gid),
1262 from_kuid_munged(user_ns, msq->q_perm.cuid),
1263 from_kgid_munged(user_ns, msq->q_perm.cgid),
1264 msq->q_stime,
1265 msq->q_rtime,
1266 msq->q_ctime);
1267
1268 return 0;
1269}
1270#endif
1271
1272int __init msg_init(void)
1273{
1274 const int err = msg_init_ns(&init_ipc_ns);
1275
1276 ipc_init_proc_interface("sysvipc/msg",
1277 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
1278 IPC_MSG_IDS, sysvipc_msg_proc_show);
1279 return err;
1280}