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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 kfree(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 = kmalloc(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 kfree(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 struct task_struct *r_tsk;
255
256 r_tsk = get_task_struct(msr->r_tsk);
257
258 /* see MSG_BARRIER for purpose/pairing */
259 smp_store_release(&msr->r_msg, ERR_PTR(res));
260 wake_q_add_safe(wake_q, r_tsk);
261 }
262}
263
264/*
265 * freeque() wakes up waiters on the sender and receiver waiting queue,
266 * removes the message queue from message queue ID IDR, and cleans up all the
267 * messages associated with this queue.
268 *
269 * msg_ids.rwsem (writer) and the spinlock for this message queue are held
270 * before freeque() is called. msg_ids.rwsem remains locked on exit.
271 */
272static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
273 __releases(RCU)
274 __releases(&msq->q_perm)
275{
276 struct msg_msg *msg, *t;
277 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
278 DEFINE_WAKE_Q(wake_q);
279
280 expunge_all(msq, -EIDRM, &wake_q);
281 ss_wakeup(msq, &wake_q, true);
282 msg_rmid(ns, msq);
283 ipc_unlock_object(&msq->q_perm);
284 wake_up_q(&wake_q);
285 rcu_read_unlock();
286
287 list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
288 atomic_dec(&ns->msg_hdrs);
289 free_msg(msg);
290 }
291 atomic_sub(msq->q_cbytes, &ns->msg_bytes);
292 ipc_update_pid(&msq->q_lspid, NULL);
293 ipc_update_pid(&msq->q_lrpid, NULL);
294 ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
295}
296
297long ksys_msgget(key_t key, int msgflg)
298{
299 struct ipc_namespace *ns;
300 static const struct ipc_ops msg_ops = {
301 .getnew = newque,
302 .associate = security_msg_queue_associate,
303 };
304 struct ipc_params msg_params;
305
306 ns = current->nsproxy->ipc_ns;
307
308 msg_params.key = key;
309 msg_params.flg = msgflg;
310
311 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
312}
313
314SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
315{
316 return ksys_msgget(key, msgflg);
317}
318
319static inline unsigned long
320copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
321{
322 switch (version) {
323 case IPC_64:
324 return copy_to_user(buf, in, sizeof(*in));
325 case IPC_OLD:
326 {
327 struct msqid_ds out;
328
329 memset(&out, 0, sizeof(out));
330
331 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
332
333 out.msg_stime = in->msg_stime;
334 out.msg_rtime = in->msg_rtime;
335 out.msg_ctime = in->msg_ctime;
336
337 if (in->msg_cbytes > USHRT_MAX)
338 out.msg_cbytes = USHRT_MAX;
339 else
340 out.msg_cbytes = in->msg_cbytes;
341 out.msg_lcbytes = in->msg_cbytes;
342
343 if (in->msg_qnum > USHRT_MAX)
344 out.msg_qnum = USHRT_MAX;
345 else
346 out.msg_qnum = in->msg_qnum;
347
348 if (in->msg_qbytes > USHRT_MAX)
349 out.msg_qbytes = USHRT_MAX;
350 else
351 out.msg_qbytes = in->msg_qbytes;
352 out.msg_lqbytes = in->msg_qbytes;
353
354 out.msg_lspid = in->msg_lspid;
355 out.msg_lrpid = in->msg_lrpid;
356
357 return copy_to_user(buf, &out, sizeof(out));
358 }
359 default:
360 return -EINVAL;
361 }
362}
363
364static inline unsigned long
365copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
366{
367 switch (version) {
368 case IPC_64:
369 if (copy_from_user(out, buf, sizeof(*out)))
370 return -EFAULT;
371 return 0;
372 case IPC_OLD:
373 {
374 struct msqid_ds tbuf_old;
375
376 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
377 return -EFAULT;
378
379 out->msg_perm.uid = tbuf_old.msg_perm.uid;
380 out->msg_perm.gid = tbuf_old.msg_perm.gid;
381 out->msg_perm.mode = tbuf_old.msg_perm.mode;
382
383 if (tbuf_old.msg_qbytes == 0)
384 out->msg_qbytes = tbuf_old.msg_lqbytes;
385 else
386 out->msg_qbytes = tbuf_old.msg_qbytes;
387
388 return 0;
389 }
390 default:
391 return -EINVAL;
392 }
393}
394
395/*
396 * This function handles some msgctl commands which require the rwsem
397 * to be held in write mode.
398 * NOTE: no locks must be held, the rwsem is taken inside this function.
399 */
400static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
401 struct ipc64_perm *perm, int msg_qbytes)
402{
403 struct kern_ipc_perm *ipcp;
404 struct msg_queue *msq;
405 int err;
406
407 down_write(&msg_ids(ns).rwsem);
408 rcu_read_lock();
409
410 ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd,
411 perm, msg_qbytes);
412 if (IS_ERR(ipcp)) {
413 err = PTR_ERR(ipcp);
414 goto out_unlock1;
415 }
416
417 msq = container_of(ipcp, struct msg_queue, q_perm);
418
419 err = security_msg_queue_msgctl(&msq->q_perm, cmd);
420 if (err)
421 goto out_unlock1;
422
423 switch (cmd) {
424 case IPC_RMID:
425 ipc_lock_object(&msq->q_perm);
426 /* freeque unlocks the ipc object and rcu */
427 freeque(ns, ipcp);
428 goto out_up;
429 case IPC_SET:
430 {
431 DEFINE_WAKE_Q(wake_q);
432
433 if (msg_qbytes > ns->msg_ctlmnb &&
434 !capable(CAP_SYS_RESOURCE)) {
435 err = -EPERM;
436 goto out_unlock1;
437 }
438
439 ipc_lock_object(&msq->q_perm);
440 err = ipc_update_perm(perm, ipcp);
441 if (err)
442 goto out_unlock0;
443
444 msq->q_qbytes = msg_qbytes;
445
446 msq->q_ctime = ktime_get_real_seconds();
447 /*
448 * Sleeping receivers might be excluded by
449 * stricter permissions.
450 */
451 expunge_all(msq, -EAGAIN, &wake_q);
452 /*
453 * Sleeping senders might be able to send
454 * due to a larger queue size.
455 */
456 ss_wakeup(msq, &wake_q, false);
457 ipc_unlock_object(&msq->q_perm);
458 wake_up_q(&wake_q);
459
460 goto out_unlock1;
461 }
462 default:
463 err = -EINVAL;
464 goto out_unlock1;
465 }
466
467out_unlock0:
468 ipc_unlock_object(&msq->q_perm);
469out_unlock1:
470 rcu_read_unlock();
471out_up:
472 up_write(&msg_ids(ns).rwsem);
473 return err;
474}
475
476static int msgctl_info(struct ipc_namespace *ns, int msqid,
477 int cmd, struct msginfo *msginfo)
478{
479 int err;
480 int max_idx;
481
482 /*
483 * We must not return kernel stack data.
484 * due to padding, it's not enough
485 * to set all member fields.
486 */
487 err = security_msg_queue_msgctl(NULL, cmd);
488 if (err)
489 return err;
490
491 memset(msginfo, 0, sizeof(*msginfo));
492 msginfo->msgmni = ns->msg_ctlmni;
493 msginfo->msgmax = ns->msg_ctlmax;
494 msginfo->msgmnb = ns->msg_ctlmnb;
495 msginfo->msgssz = MSGSSZ;
496 msginfo->msgseg = MSGSEG;
497 down_read(&msg_ids(ns).rwsem);
498 if (cmd == MSG_INFO) {
499 msginfo->msgpool = msg_ids(ns).in_use;
500 msginfo->msgmap = atomic_read(&ns->msg_hdrs);
501 msginfo->msgtql = atomic_read(&ns->msg_bytes);
502 } else {
503 msginfo->msgmap = MSGMAP;
504 msginfo->msgpool = MSGPOOL;
505 msginfo->msgtql = MSGTQL;
506 }
507 max_idx = ipc_get_maxidx(&msg_ids(ns));
508 up_read(&msg_ids(ns).rwsem);
509 return (max_idx < 0) ? 0 : max_idx;
510}
511
512static int msgctl_stat(struct ipc_namespace *ns, int msqid,
513 int cmd, struct msqid64_ds *p)
514{
515 struct msg_queue *msq;
516 int err;
517
518 memset(p, 0, sizeof(*p));
519
520 rcu_read_lock();
521 if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) {
522 msq = msq_obtain_object(ns, msqid);
523 if (IS_ERR(msq)) {
524 err = PTR_ERR(msq);
525 goto out_unlock;
526 }
527 } else { /* IPC_STAT */
528 msq = msq_obtain_object_check(ns, msqid);
529 if (IS_ERR(msq)) {
530 err = PTR_ERR(msq);
531 goto out_unlock;
532 }
533 }
534
535 /* see comment for SHM_STAT_ANY */
536 if (cmd == MSG_STAT_ANY)
537 audit_ipc_obj(&msq->q_perm);
538 else {
539 err = -EACCES;
540 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
541 goto out_unlock;
542 }
543
544 err = security_msg_queue_msgctl(&msq->q_perm, cmd);
545 if (err)
546 goto out_unlock;
547
548 ipc_lock_object(&msq->q_perm);
549
550 if (!ipc_valid_object(&msq->q_perm)) {
551 ipc_unlock_object(&msq->q_perm);
552 err = -EIDRM;
553 goto out_unlock;
554 }
555
556 kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm);
557 p->msg_stime = msq->q_stime;
558 p->msg_rtime = msq->q_rtime;
559 p->msg_ctime = msq->q_ctime;
560#ifndef CONFIG_64BIT
561 p->msg_stime_high = msq->q_stime >> 32;
562 p->msg_rtime_high = msq->q_rtime >> 32;
563 p->msg_ctime_high = msq->q_ctime >> 32;
564#endif
565 p->msg_cbytes = msq->q_cbytes;
566 p->msg_qnum = msq->q_qnum;
567 p->msg_qbytes = msq->q_qbytes;
568 p->msg_lspid = pid_vnr(msq->q_lspid);
569 p->msg_lrpid = pid_vnr(msq->q_lrpid);
570
571 if (cmd == IPC_STAT) {
572 /*
573 * As defined in SUS:
574 * Return 0 on success
575 */
576 err = 0;
577 } else {
578 /*
579 * MSG_STAT and MSG_STAT_ANY (both Linux specific)
580 * Return the full id, including the sequence number
581 */
582 err = msq->q_perm.id;
583 }
584
585 ipc_unlock_object(&msq->q_perm);
586out_unlock:
587 rcu_read_unlock();
588 return err;
589}
590
591static long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf, int version)
592{
593 struct ipc_namespace *ns;
594 struct msqid64_ds msqid64;
595 int err;
596
597 if (msqid < 0 || cmd < 0)
598 return -EINVAL;
599
600 ns = current->nsproxy->ipc_ns;
601
602 switch (cmd) {
603 case IPC_INFO:
604 case MSG_INFO: {
605 struct msginfo msginfo;
606 err = msgctl_info(ns, msqid, cmd, &msginfo);
607 if (err < 0)
608 return err;
609 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
610 err = -EFAULT;
611 return err;
612 }
613 case MSG_STAT: /* msqid is an index rather than a msg queue id */
614 case MSG_STAT_ANY:
615 case IPC_STAT:
616 err = msgctl_stat(ns, msqid, cmd, &msqid64);
617 if (err < 0)
618 return err;
619 if (copy_msqid_to_user(buf, &msqid64, version))
620 err = -EFAULT;
621 return err;
622 case IPC_SET:
623 if (copy_msqid_from_user(&msqid64, buf, version))
624 return -EFAULT;
625 return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm,
626 msqid64.msg_qbytes);
627 case IPC_RMID:
628 return msgctl_down(ns, msqid, cmd, NULL, 0);
629 default:
630 return -EINVAL;
631 }
632}
633
634SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
635{
636 return ksys_msgctl(msqid, cmd, buf, IPC_64);
637}
638
639#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
640long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
641{
642 int version = ipc_parse_version(&cmd);
643
644 return ksys_msgctl(msqid, cmd, buf, version);
645}
646
647SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
648{
649 return ksys_old_msgctl(msqid, cmd, buf);
650}
651#endif
652
653#ifdef CONFIG_COMPAT
654
655struct compat_msqid_ds {
656 struct compat_ipc_perm msg_perm;
657 compat_uptr_t msg_first;
658 compat_uptr_t msg_last;
659 old_time32_t msg_stime;
660 old_time32_t msg_rtime;
661 old_time32_t msg_ctime;
662 compat_ulong_t msg_lcbytes;
663 compat_ulong_t msg_lqbytes;
664 unsigned short msg_cbytes;
665 unsigned short msg_qnum;
666 unsigned short msg_qbytes;
667 compat_ipc_pid_t msg_lspid;
668 compat_ipc_pid_t msg_lrpid;
669};
670
671static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf,
672 int version)
673{
674 memset(out, 0, sizeof(*out));
675 if (version == IPC_64) {
676 struct compat_msqid64_ds __user *p = buf;
677 if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm))
678 return -EFAULT;
679 if (get_user(out->msg_qbytes, &p->msg_qbytes))
680 return -EFAULT;
681 } else {
682 struct compat_msqid_ds __user *p = buf;
683 if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm))
684 return -EFAULT;
685 if (get_user(out->msg_qbytes, &p->msg_qbytes))
686 return -EFAULT;
687 }
688 return 0;
689}
690
691static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in,
692 int version)
693{
694 if (version == IPC_64) {
695 struct compat_msqid64_ds v;
696 memset(&v, 0, sizeof(v));
697 to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm);
698 v.msg_stime = lower_32_bits(in->msg_stime);
699 v.msg_stime_high = upper_32_bits(in->msg_stime);
700 v.msg_rtime = lower_32_bits(in->msg_rtime);
701 v.msg_rtime_high = upper_32_bits(in->msg_rtime);
702 v.msg_ctime = lower_32_bits(in->msg_ctime);
703 v.msg_ctime_high = upper_32_bits(in->msg_ctime);
704 v.msg_cbytes = in->msg_cbytes;
705 v.msg_qnum = in->msg_qnum;
706 v.msg_qbytes = in->msg_qbytes;
707 v.msg_lspid = in->msg_lspid;
708 v.msg_lrpid = in->msg_lrpid;
709 return copy_to_user(buf, &v, sizeof(v));
710 } else {
711 struct compat_msqid_ds v;
712 memset(&v, 0, sizeof(v));
713 to_compat_ipc_perm(&v.msg_perm, &in->msg_perm);
714 v.msg_stime = in->msg_stime;
715 v.msg_rtime = in->msg_rtime;
716 v.msg_ctime = in->msg_ctime;
717 v.msg_cbytes = in->msg_cbytes;
718 v.msg_qnum = in->msg_qnum;
719 v.msg_qbytes = in->msg_qbytes;
720 v.msg_lspid = in->msg_lspid;
721 v.msg_lrpid = in->msg_lrpid;
722 return copy_to_user(buf, &v, sizeof(v));
723 }
724}
725
726static long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr, int version)
727{
728 struct ipc_namespace *ns;
729 int err;
730 struct msqid64_ds msqid64;
731
732 ns = current->nsproxy->ipc_ns;
733
734 if (msqid < 0 || cmd < 0)
735 return -EINVAL;
736
737 switch (cmd & (~IPC_64)) {
738 case IPC_INFO:
739 case MSG_INFO: {
740 struct msginfo msginfo;
741 err = msgctl_info(ns, msqid, cmd, &msginfo);
742 if (err < 0)
743 return err;
744 if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo)))
745 err = -EFAULT;
746 return err;
747 }
748 case IPC_STAT:
749 case MSG_STAT:
750 case MSG_STAT_ANY:
751 err = msgctl_stat(ns, msqid, cmd, &msqid64);
752 if (err < 0)
753 return err;
754 if (copy_compat_msqid_to_user(uptr, &msqid64, version))
755 err = -EFAULT;
756 return err;
757 case IPC_SET:
758 if (copy_compat_msqid_from_user(&msqid64, uptr, version))
759 return -EFAULT;
760 return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes);
761 case IPC_RMID:
762 return msgctl_down(ns, msqid, cmd, NULL, 0);
763 default:
764 return -EINVAL;
765 }
766}
767
768COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)
769{
770 return compat_ksys_msgctl(msqid, cmd, uptr, IPC_64);
771}
772
773#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
774long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr)
775{
776 int version = compat_ipc_parse_version(&cmd);
777
778 return compat_ksys_msgctl(msqid, cmd, uptr, version);
779}
780
781COMPAT_SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, void __user *, uptr)
782{
783 return compat_ksys_old_msgctl(msqid, cmd, uptr);
784}
785#endif
786#endif
787
788static int testmsg(struct msg_msg *msg, long type, int mode)
789{
790 switch (mode) {
791 case SEARCH_ANY:
792 case SEARCH_NUMBER:
793 return 1;
794 case SEARCH_LESSEQUAL:
795 if (msg->m_type <= type)
796 return 1;
797 break;
798 case SEARCH_EQUAL:
799 if (msg->m_type == type)
800 return 1;
801 break;
802 case SEARCH_NOTEQUAL:
803 if (msg->m_type != type)
804 return 1;
805 break;
806 }
807 return 0;
808}
809
810static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg,
811 struct wake_q_head *wake_q)
812{
813 struct msg_receiver *msr, *t;
814
815 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
816 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
817 !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk,
818 msr->r_msgtype, msr->r_mode)) {
819
820 list_del(&msr->r_list);
821 if (msr->r_maxsize < msg->m_ts) {
822 wake_q_add(wake_q, msr->r_tsk);
823
824 /* See expunge_all regarding memory barrier */
825 smp_store_release(&msr->r_msg, ERR_PTR(-E2BIG));
826 } else {
827 ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk));
828 msq->q_rtime = ktime_get_real_seconds();
829
830 wake_q_add(wake_q, msr->r_tsk);
831
832 /* See expunge_all regarding memory barrier */
833 smp_store_release(&msr->r_msg, msg);
834 return 1;
835 }
836 }
837 }
838
839 return 0;
840}
841
842static long do_msgsnd(int msqid, long mtype, void __user *mtext,
843 size_t msgsz, int msgflg)
844{
845 struct msg_queue *msq;
846 struct msg_msg *msg;
847 int err;
848 struct ipc_namespace *ns;
849 DEFINE_WAKE_Q(wake_q);
850
851 ns = current->nsproxy->ipc_ns;
852
853 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
854 return -EINVAL;
855 if (mtype < 1)
856 return -EINVAL;
857
858 msg = load_msg(mtext, msgsz);
859 if (IS_ERR(msg))
860 return PTR_ERR(msg);
861
862 msg->m_type = mtype;
863 msg->m_ts = msgsz;
864
865 rcu_read_lock();
866 msq = msq_obtain_object_check(ns, msqid);
867 if (IS_ERR(msq)) {
868 err = PTR_ERR(msq);
869 goto out_unlock1;
870 }
871
872 ipc_lock_object(&msq->q_perm);
873
874 for (;;) {
875 struct msg_sender s;
876
877 err = -EACCES;
878 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
879 goto out_unlock0;
880
881 /* raced with RMID? */
882 if (!ipc_valid_object(&msq->q_perm)) {
883 err = -EIDRM;
884 goto out_unlock0;
885 }
886
887 err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg);
888 if (err)
889 goto out_unlock0;
890
891 if (msg_fits_inqueue(msq, msgsz))
892 break;
893
894 /* queue full, wait: */
895 if (msgflg & IPC_NOWAIT) {
896 err = -EAGAIN;
897 goto out_unlock0;
898 }
899
900 /* enqueue the sender and prepare to block */
901 ss_add(msq, &s, msgsz);
902
903 if (!ipc_rcu_getref(&msq->q_perm)) {
904 err = -EIDRM;
905 goto out_unlock0;
906 }
907
908 ipc_unlock_object(&msq->q_perm);
909 rcu_read_unlock();
910 schedule();
911
912 rcu_read_lock();
913 ipc_lock_object(&msq->q_perm);
914
915 ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
916 /* raced with RMID? */
917 if (!ipc_valid_object(&msq->q_perm)) {
918 err = -EIDRM;
919 goto out_unlock0;
920 }
921 ss_del(&s);
922
923 if (signal_pending(current)) {
924 err = -ERESTARTNOHAND;
925 goto out_unlock0;
926 }
927
928 }
929
930 ipc_update_pid(&msq->q_lspid, task_tgid(current));
931 msq->q_stime = ktime_get_real_seconds();
932
933 if (!pipelined_send(msq, msg, &wake_q)) {
934 /* no one is waiting for this message, enqueue it */
935 list_add_tail(&msg->m_list, &msq->q_messages);
936 msq->q_cbytes += msgsz;
937 msq->q_qnum++;
938 atomic_add(msgsz, &ns->msg_bytes);
939 atomic_inc(&ns->msg_hdrs);
940 }
941
942 err = 0;
943 msg = NULL;
944
945out_unlock0:
946 ipc_unlock_object(&msq->q_perm);
947 wake_up_q(&wake_q);
948out_unlock1:
949 rcu_read_unlock();
950 if (msg != NULL)
951 free_msg(msg);
952 return err;
953}
954
955long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
956 int msgflg)
957{
958 long mtype;
959
960 if (get_user(mtype, &msgp->mtype))
961 return -EFAULT;
962 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
963}
964
965SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
966 int, msgflg)
967{
968 return ksys_msgsnd(msqid, msgp, msgsz, msgflg);
969}
970
971#ifdef CONFIG_COMPAT
972
973struct compat_msgbuf {
974 compat_long_t mtype;
975 char mtext[1];
976};
977
978long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
979 compat_ssize_t msgsz, int msgflg)
980{
981 struct compat_msgbuf __user *up = compat_ptr(msgp);
982 compat_long_t mtype;
983
984 if (get_user(mtype, &up->mtype))
985 return -EFAULT;
986 return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg);
987}
988
989COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
990 compat_ssize_t, msgsz, int, msgflg)
991{
992 return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg);
993}
994#endif
995
996static inline int convert_mode(long *msgtyp, int msgflg)
997{
998 if (msgflg & MSG_COPY)
999 return SEARCH_NUMBER;
1000 /*
1001 * find message of correct type.
1002 * msgtyp = 0 => get first.
1003 * msgtyp > 0 => get first message of matching type.
1004 * msgtyp < 0 => get message with least type must be < abs(msgtype).
1005 */
1006 if (*msgtyp == 0)
1007 return SEARCH_ANY;
1008 if (*msgtyp < 0) {
1009 if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */
1010 *msgtyp = LONG_MAX;
1011 else
1012 *msgtyp = -*msgtyp;
1013 return SEARCH_LESSEQUAL;
1014 }
1015 if (msgflg & MSG_EXCEPT)
1016 return SEARCH_NOTEQUAL;
1017 return SEARCH_EQUAL;
1018}
1019
1020static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
1021{
1022 struct msgbuf __user *msgp = dest;
1023 size_t msgsz;
1024
1025 if (put_user(msg->m_type, &msgp->mtype))
1026 return -EFAULT;
1027
1028 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
1029 if (store_msg(msgp->mtext, msg, msgsz))
1030 return -EFAULT;
1031 return msgsz;
1032}
1033
1034#ifdef CONFIG_CHECKPOINT_RESTORE
1035/*
1036 * This function creates new kernel message structure, large enough to store
1037 * bufsz message bytes.
1038 */
1039static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
1040{
1041 struct msg_msg *copy;
1042
1043 /*
1044 * Create dummy message to copy real message to.
1045 */
1046 copy = load_msg(buf, bufsz);
1047 if (!IS_ERR(copy))
1048 copy->m_ts = bufsz;
1049 return copy;
1050}
1051
1052static inline void free_copy(struct msg_msg *copy)
1053{
1054 if (copy)
1055 free_msg(copy);
1056}
1057#else
1058static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
1059{
1060 return ERR_PTR(-ENOSYS);
1061}
1062
1063static inline void free_copy(struct msg_msg *copy)
1064{
1065}
1066#endif
1067
1068static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
1069{
1070 struct msg_msg *msg, *found = NULL;
1071 long count = 0;
1072
1073 list_for_each_entry(msg, &msq->q_messages, m_list) {
1074 if (testmsg(msg, *msgtyp, mode) &&
1075 !security_msg_queue_msgrcv(&msq->q_perm, msg, current,
1076 *msgtyp, mode)) {
1077 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
1078 *msgtyp = msg->m_type - 1;
1079 found = msg;
1080 } else if (mode == SEARCH_NUMBER) {
1081 if (*msgtyp == count)
1082 return msg;
1083 } else
1084 return msg;
1085 count++;
1086 }
1087 }
1088
1089 return found ?: ERR_PTR(-EAGAIN);
1090}
1091
1092static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg,
1093 long (*msg_handler)(void __user *, struct msg_msg *, size_t))
1094{
1095 int mode;
1096 struct msg_queue *msq;
1097 struct ipc_namespace *ns;
1098 struct msg_msg *msg, *copy = NULL;
1099 DEFINE_WAKE_Q(wake_q);
1100
1101 ns = current->nsproxy->ipc_ns;
1102
1103 if (msqid < 0 || (long) bufsz < 0)
1104 return -EINVAL;
1105
1106 if (msgflg & MSG_COPY) {
1107 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
1108 return -EINVAL;
1109 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
1110 if (IS_ERR(copy))
1111 return PTR_ERR(copy);
1112 }
1113 mode = convert_mode(&msgtyp, msgflg);
1114
1115 rcu_read_lock();
1116 msq = msq_obtain_object_check(ns, msqid);
1117 if (IS_ERR(msq)) {
1118 rcu_read_unlock();
1119 free_copy(copy);
1120 return PTR_ERR(msq);
1121 }
1122
1123 for (;;) {
1124 struct msg_receiver msr_d;
1125
1126 msg = ERR_PTR(-EACCES);
1127 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
1128 goto out_unlock1;
1129
1130 ipc_lock_object(&msq->q_perm);
1131
1132 /* raced with RMID? */
1133 if (!ipc_valid_object(&msq->q_perm)) {
1134 msg = ERR_PTR(-EIDRM);
1135 goto out_unlock0;
1136 }
1137
1138 msg = find_msg(msq, &msgtyp, mode);
1139 if (!IS_ERR(msg)) {
1140 /*
1141 * Found a suitable message.
1142 * Unlink it from the queue.
1143 */
1144 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
1145 msg = ERR_PTR(-E2BIG);
1146 goto out_unlock0;
1147 }
1148 /*
1149 * If we are copying, then do not unlink message and do
1150 * not update queue parameters.
1151 */
1152 if (msgflg & MSG_COPY) {
1153 msg = copy_msg(msg, copy);
1154 goto out_unlock0;
1155 }
1156
1157 list_del(&msg->m_list);
1158 msq->q_qnum--;
1159 msq->q_rtime = ktime_get_real_seconds();
1160 ipc_update_pid(&msq->q_lrpid, task_tgid(current));
1161 msq->q_cbytes -= msg->m_ts;
1162 atomic_sub(msg->m_ts, &ns->msg_bytes);
1163 atomic_dec(&ns->msg_hdrs);
1164 ss_wakeup(msq, &wake_q, false);
1165
1166 goto out_unlock0;
1167 }
1168
1169 /* No message waiting. Wait for a message */
1170 if (msgflg & IPC_NOWAIT) {
1171 msg = ERR_PTR(-ENOMSG);
1172 goto out_unlock0;
1173 }
1174
1175 list_add_tail(&msr_d.r_list, &msq->q_receivers);
1176 msr_d.r_tsk = current;
1177 msr_d.r_msgtype = msgtyp;
1178 msr_d.r_mode = mode;
1179 if (msgflg & MSG_NOERROR)
1180 msr_d.r_maxsize = INT_MAX;
1181 else
1182 msr_d.r_maxsize = bufsz;
1183
1184 /* memory barrier not require due to ipc_lock_object() */
1185 WRITE_ONCE(msr_d.r_msg, ERR_PTR(-EAGAIN));
1186
1187 /* memory barrier not required, we own ipc_lock_object() */
1188 __set_current_state(TASK_INTERRUPTIBLE);
1189
1190 ipc_unlock_object(&msq->q_perm);
1191 rcu_read_unlock();
1192 schedule();
1193
1194 /*
1195 * Lockless receive, part 1:
1196 * We don't hold a reference to the queue and getting a
1197 * reference would defeat the idea of a lockless operation,
1198 * thus the code relies on rcu to guarantee the existence of
1199 * msq:
1200 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
1201 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
1202 */
1203 rcu_read_lock();
1204
1205 /*
1206 * Lockless receive, part 2:
1207 * The work in pipelined_send() and expunge_all():
1208 * - Set pointer to message
1209 * - Queue the receiver task for later wakeup
1210 * - Wake up the process after the lock is dropped.
1211 *
1212 * Should the process wake up before this wakeup (due to a
1213 * signal) it will either see the message and continue ...
1214 */
1215 msg = READ_ONCE(msr_d.r_msg);
1216 if (msg != ERR_PTR(-EAGAIN)) {
1217 /* see MSG_BARRIER for purpose/pairing */
1218 smp_acquire__after_ctrl_dep();
1219
1220 goto out_unlock1;
1221 }
1222
1223 /*
1224 * ... or see -EAGAIN, acquire the lock to check the message
1225 * again.
1226 */
1227 ipc_lock_object(&msq->q_perm);
1228
1229 msg = READ_ONCE(msr_d.r_msg);
1230 if (msg != ERR_PTR(-EAGAIN))
1231 goto out_unlock0;
1232
1233 list_del(&msr_d.r_list);
1234 if (signal_pending(current)) {
1235 msg = ERR_PTR(-ERESTARTNOHAND);
1236 goto out_unlock0;
1237 }
1238
1239 ipc_unlock_object(&msq->q_perm);
1240 }
1241
1242out_unlock0:
1243 ipc_unlock_object(&msq->q_perm);
1244 wake_up_q(&wake_q);
1245out_unlock1:
1246 rcu_read_unlock();
1247 if (IS_ERR(msg)) {
1248 free_copy(copy);
1249 return PTR_ERR(msg);
1250 }
1251
1252 bufsz = msg_handler(buf, msg, bufsz);
1253 free_msg(msg);
1254
1255 return bufsz;
1256}
1257
1258long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
1259 long msgtyp, int msgflg)
1260{
1261 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
1262}
1263
1264SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
1265 long, msgtyp, int, msgflg)
1266{
1267 return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1268}
1269
1270#ifdef CONFIG_COMPAT
1271static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
1272{
1273 struct compat_msgbuf __user *msgp = dest;
1274 size_t msgsz;
1275
1276 if (put_user(msg->m_type, &msgp->mtype))
1277 return -EFAULT;
1278
1279 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
1280 if (store_msg(msgp->mtext, msg, msgsz))
1281 return -EFAULT;
1282 return msgsz;
1283}
1284
1285long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
1286 compat_long_t msgtyp, int msgflg)
1287{
1288 return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp,
1289 msgflg, compat_do_msg_fill);
1290}
1291
1292COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
1293 compat_ssize_t, msgsz, compat_long_t, msgtyp,
1294 int, msgflg)
1295{
1296 return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1297}
1298#endif
1299
1300void msg_init_ns(struct ipc_namespace *ns)
1301{
1302 ns->msg_ctlmax = MSGMAX;
1303 ns->msg_ctlmnb = MSGMNB;
1304 ns->msg_ctlmni = MSGMNI;
1305
1306 atomic_set(&ns->msg_bytes, 0);
1307 atomic_set(&ns->msg_hdrs, 0);
1308 ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
1309}
1310
1311#ifdef CONFIG_IPC_NS
1312void msg_exit_ns(struct ipc_namespace *ns)
1313{
1314 free_ipcs(ns, &msg_ids(ns), freeque);
1315 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
1316 rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht);
1317}
1318#endif
1319
1320#ifdef CONFIG_PROC_FS
1321static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
1322{
1323 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1324 struct user_namespace *user_ns = seq_user_ns(s);
1325 struct kern_ipc_perm *ipcp = it;
1326 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
1327
1328 seq_printf(s,
1329 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n",
1330 msq->q_perm.key,
1331 msq->q_perm.id,
1332 msq->q_perm.mode,
1333 msq->q_cbytes,
1334 msq->q_qnum,
1335 pid_nr_ns(msq->q_lspid, pid_ns),
1336 pid_nr_ns(msq->q_lrpid, pid_ns),
1337 from_kuid_munged(user_ns, msq->q_perm.uid),
1338 from_kgid_munged(user_ns, msq->q_perm.gid),
1339 from_kuid_munged(user_ns, msq->q_perm.cuid),
1340 from_kgid_munged(user_ns, msq->q_perm.cgid),
1341 msq->q_stime,
1342 msq->q_rtime,
1343 msq->q_ctime);
1344
1345 return 0;
1346}
1347#endif
1348
1349void __init msg_init(void)
1350{
1351 msg_init_ns(&init_ipc_ns);
1352
1353 ipc_init_proc_interface("sysvipc/msg",
1354 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
1355 IPC_MSG_IDS, sysvipc_msg_proc_show);
1356}
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}