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25#include <linux/capability.h>
26#include <linux/msg.h>
27#include <linux/spinlock.h>
28#include <linux/init.h>
29#include <linux/mm.h>
30#include <linux/proc_fs.h>
31#include <linux/list.h>
32#include <linux/security.h>
33#include <linux/sched.h>
34#include <linux/syscalls.h>
35#include <linux/audit.h>
36#include <linux/seq_file.h>
37#include <linux/rwsem.h>
38#include <linux/nsproxy.h>
39#include <linux/ipc_namespace.h>
40
41#include <asm/current.h>
42#include <linux/uaccess.h>
43#include "util.h"
44
45
46struct msg_receiver {
47 struct list_head r_list;
48 struct task_struct *r_tsk;
49
50 int r_mode;
51 long r_msgtype;
52 long r_maxsize;
53
54 struct msg_msg *r_msg;
55};
56
57
58struct msg_sender {
59 struct list_head list;
60 struct task_struct *tsk;
61 size_t msgsz;
62};
63
64#define SEARCH_ANY 1
65#define SEARCH_EQUAL 2
66#define SEARCH_NOTEQUAL 3
67#define SEARCH_LESSEQUAL 4
68#define SEARCH_NUMBER 5
69
70#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
71
72static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
73{
74 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&msg_ids(ns), id);
75
76 if (IS_ERR(ipcp))
77 return ERR_CAST(ipcp);
78
79 return container_of(ipcp, struct msg_queue, q_perm);
80}
81
82static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
83 int id)
84{
85 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
86
87 if (IS_ERR(ipcp))
88 return ERR_CAST(ipcp);
89
90 return container_of(ipcp, struct msg_queue, q_perm);
91}
92
93static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
94{
95 ipc_rmid(&msg_ids(ns), &s->q_perm);
96}
97
98static void msg_rcu_free(struct rcu_head *head)
99{
100 struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
101 struct msg_queue *msq = ipc_rcu_to_struct(p);
102
103 security_msg_queue_free(msq);
104 ipc_rcu_free(head);
105}
106
107
108
109
110
111
112
113
114static int newque(struct ipc_namespace *ns, struct ipc_params *params)
115{
116 struct msg_queue *msq;
117 int id, retval;
118 key_t key = params->key;
119 int msgflg = params->flg;
120
121 msq = ipc_rcu_alloc(sizeof(*msq));
122 if (!msq)
123 return -ENOMEM;
124
125 msq->q_perm.mode = msgflg & S_IRWXUGO;
126 msq->q_perm.key = key;
127
128 msq->q_perm.security = NULL;
129 retval = security_msg_queue_alloc(msq);
130 if (retval) {
131 ipc_rcu_putref(msq, ipc_rcu_free);
132 return retval;
133 }
134
135 msq->q_stime = msq->q_rtime = 0;
136 msq->q_ctime = get_seconds();
137 msq->q_cbytes = msq->q_qnum = 0;
138 msq->q_qbytes = ns->msg_ctlmnb;
139 msq->q_lspid = msq->q_lrpid = 0;
140 INIT_LIST_HEAD(&msq->q_messages);
141 INIT_LIST_HEAD(&msq->q_receivers);
142 INIT_LIST_HEAD(&msq->q_senders);
143
144
145 id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
146 if (id < 0) {
147 ipc_rcu_putref(msq, msg_rcu_free);
148 return id;
149 }
150
151 ipc_unlock_object(&msq->q_perm);
152 rcu_read_unlock();
153
154 return msq->q_perm.id;
155}
156
157static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz)
158{
159 return msgsz + msq->q_cbytes <= msq->q_qbytes &&
160 1 + msq->q_qnum <= msq->q_qbytes;
161}
162
163static inline void ss_add(struct msg_queue *msq,
164 struct msg_sender *mss, size_t msgsz)
165{
166 mss->tsk = current;
167 mss->msgsz = msgsz;
168 __set_current_state(TASK_INTERRUPTIBLE);
169 list_add_tail(&mss->list, &msq->q_senders);
170}
171
172static inline void ss_del(struct msg_sender *mss)
173{
174 if (mss->list.next)
175 list_del(&mss->list);
176}
177
178static void ss_wakeup(struct msg_queue *msq,
179 struct wake_q_head *wake_q, bool kill)
180{
181 struct msg_sender *mss, *t;
182 struct task_struct *stop_tsk = NULL;
183 struct list_head *h = &msq->q_senders;
184
185 list_for_each_entry_safe(mss, t, h, list) {
186 if (kill)
187 mss->list.next = NULL;
188
189
190
191
192
193
194 else if (stop_tsk == mss->tsk)
195 break;
196
197
198
199
200
201
202
203 else if (!msg_fits_inqueue(msq, mss->msgsz)) {
204 if (!stop_tsk)
205 stop_tsk = mss->tsk;
206
207 list_move_tail(&mss->list, &msq->q_senders);
208 continue;
209 }
210
211 wake_q_add(wake_q, mss->tsk);
212 }
213}
214
215static void expunge_all(struct msg_queue *msq, int res,
216 struct wake_q_head *wake_q)
217{
218 struct msg_receiver *msr, *t;
219
220 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
221 wake_q_add(wake_q, msr->r_tsk);
222 WRITE_ONCE(msr->r_msg, ERR_PTR(res));
223 }
224}
225
226
227
228
229
230
231
232
233
234static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
235{
236 struct msg_msg *msg, *t;
237 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
238 WAKE_Q(wake_q);
239
240 expunge_all(msq, -EIDRM, &wake_q);
241 ss_wakeup(msq, &wake_q, true);
242 msg_rmid(ns, msq);
243 ipc_unlock_object(&msq->q_perm);
244 wake_up_q(&wake_q);
245 rcu_read_unlock();
246
247 list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
248 atomic_dec(&ns->msg_hdrs);
249 free_msg(msg);
250 }
251 atomic_sub(msq->q_cbytes, &ns->msg_bytes);
252 ipc_rcu_putref(msq, msg_rcu_free);
253}
254
255
256
257
258static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
259{
260 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
261
262 return security_msg_queue_associate(msq, msgflg);
263}
264
265SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
266{
267 struct ipc_namespace *ns;
268 static const struct ipc_ops msg_ops = {
269 .getnew = newque,
270 .associate = msg_security,
271 };
272 struct ipc_params msg_params;
273
274 ns = current->nsproxy->ipc_ns;
275
276 msg_params.key = key;
277 msg_params.flg = msgflg;
278
279 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
280}
281
282static inline unsigned long
283copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
284{
285 switch (version) {
286 case IPC_64:
287 return copy_to_user(buf, in, sizeof(*in));
288 case IPC_OLD:
289 {
290 struct msqid_ds out;
291
292 memset(&out, 0, sizeof(out));
293
294 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
295
296 out.msg_stime = in->msg_stime;
297 out.msg_rtime = in->msg_rtime;
298 out.msg_ctime = in->msg_ctime;
299
300 if (in->msg_cbytes > USHRT_MAX)
301 out.msg_cbytes = USHRT_MAX;
302 else
303 out.msg_cbytes = in->msg_cbytes;
304 out.msg_lcbytes = in->msg_cbytes;
305
306 if (in->msg_qnum > USHRT_MAX)
307 out.msg_qnum = USHRT_MAX;
308 else
309 out.msg_qnum = in->msg_qnum;
310
311 if (in->msg_qbytes > USHRT_MAX)
312 out.msg_qbytes = USHRT_MAX;
313 else
314 out.msg_qbytes = in->msg_qbytes;
315 out.msg_lqbytes = in->msg_qbytes;
316
317 out.msg_lspid = in->msg_lspid;
318 out.msg_lrpid = in->msg_lrpid;
319
320 return copy_to_user(buf, &out, sizeof(out));
321 }
322 default:
323 return -EINVAL;
324 }
325}
326
327static inline unsigned long
328copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
329{
330 switch (version) {
331 case IPC_64:
332 if (copy_from_user(out, buf, sizeof(*out)))
333 return -EFAULT;
334 return 0;
335 case IPC_OLD:
336 {
337 struct msqid_ds tbuf_old;
338
339 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
340 return -EFAULT;
341
342 out->msg_perm.uid = tbuf_old.msg_perm.uid;
343 out->msg_perm.gid = tbuf_old.msg_perm.gid;
344 out->msg_perm.mode = tbuf_old.msg_perm.mode;
345
346 if (tbuf_old.msg_qbytes == 0)
347 out->msg_qbytes = tbuf_old.msg_lqbytes;
348 else
349 out->msg_qbytes = tbuf_old.msg_qbytes;
350
351 return 0;
352 }
353 default:
354 return -EINVAL;
355 }
356}
357
358
359
360
361
362
363static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
364 struct msqid_ds __user *buf, int version)
365{
366 struct kern_ipc_perm *ipcp;
367 struct msqid64_ds uninitialized_var(msqid64);
368 struct msg_queue *msq;
369 int err;
370
371 if (cmd == IPC_SET) {
372 if (copy_msqid_from_user(&msqid64, buf, version))
373 return -EFAULT;
374 }
375
376 down_write(&msg_ids(ns).rwsem);
377 rcu_read_lock();
378
379 ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
380 &msqid64.msg_perm, msqid64.msg_qbytes);
381 if (IS_ERR(ipcp)) {
382 err = PTR_ERR(ipcp);
383 goto out_unlock1;
384 }
385
386 msq = container_of(ipcp, struct msg_queue, q_perm);
387
388 err = security_msg_queue_msgctl(msq, cmd);
389 if (err)
390 goto out_unlock1;
391
392 switch (cmd) {
393 case IPC_RMID:
394 ipc_lock_object(&msq->q_perm);
395
396 freeque(ns, ipcp);
397 goto out_up;
398 case IPC_SET:
399 {
400 WAKE_Q(wake_q);
401
402 if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
403 !capable(CAP_SYS_RESOURCE)) {
404 err = -EPERM;
405 goto out_unlock1;
406 }
407
408 ipc_lock_object(&msq->q_perm);
409 err = ipc_update_perm(&msqid64.msg_perm, ipcp);
410 if (err)
411 goto out_unlock0;
412
413 msq->q_qbytes = msqid64.msg_qbytes;
414
415 msq->q_ctime = get_seconds();
416
417
418
419
420 expunge_all(msq, -EAGAIN, &wake_q);
421
422
423
424
425 ss_wakeup(msq, &wake_q, false);
426 ipc_unlock_object(&msq->q_perm);
427 wake_up_q(&wake_q);
428
429 goto out_unlock1;
430 }
431 default:
432 err = -EINVAL;
433 goto out_unlock1;
434 }
435
436out_unlock0:
437 ipc_unlock_object(&msq->q_perm);
438out_unlock1:
439 rcu_read_unlock();
440out_up:
441 up_write(&msg_ids(ns).rwsem);
442 return err;
443}
444
445static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
446 int cmd, int version, void __user *buf)
447{
448 int err;
449 struct msg_queue *msq;
450
451 switch (cmd) {
452 case IPC_INFO:
453 case MSG_INFO:
454 {
455 struct msginfo msginfo;
456 int max_id;
457
458 if (!buf)
459 return -EFAULT;
460
461
462
463
464
465
466 err = security_msg_queue_msgctl(NULL, cmd);
467 if (err)
468 return err;
469
470 memset(&msginfo, 0, sizeof(msginfo));
471 msginfo.msgmni = ns->msg_ctlmni;
472 msginfo.msgmax = ns->msg_ctlmax;
473 msginfo.msgmnb = ns->msg_ctlmnb;
474 msginfo.msgssz = MSGSSZ;
475 msginfo.msgseg = MSGSEG;
476 down_read(&msg_ids(ns).rwsem);
477 if (cmd == MSG_INFO) {
478 msginfo.msgpool = msg_ids(ns).in_use;
479 msginfo.msgmap = atomic_read(&ns->msg_hdrs);
480 msginfo.msgtql = atomic_read(&ns->msg_bytes);
481 } else {
482 msginfo.msgmap = MSGMAP;
483 msginfo.msgpool = MSGPOOL;
484 msginfo.msgtql = MSGTQL;
485 }
486 max_id = ipc_get_maxid(&msg_ids(ns));
487 up_read(&msg_ids(ns).rwsem);
488 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
489 return -EFAULT;
490 return (max_id < 0) ? 0 : max_id;
491 }
492
493 case MSG_STAT:
494 case IPC_STAT:
495 {
496 struct msqid64_ds tbuf;
497 int success_return;
498
499 if (!buf)
500 return -EFAULT;
501
502 memset(&tbuf, 0, sizeof(tbuf));
503
504 rcu_read_lock();
505 if (cmd == MSG_STAT) {
506 msq = msq_obtain_object(ns, msqid);
507 if (IS_ERR(msq)) {
508 err = PTR_ERR(msq);
509 goto out_unlock;
510 }
511 success_return = msq->q_perm.id;
512 } else {
513 msq = msq_obtain_object_check(ns, msqid);
514 if (IS_ERR(msq)) {
515 err = PTR_ERR(msq);
516 goto out_unlock;
517 }
518 success_return = 0;
519 }
520
521 err = -EACCES;
522 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
523 goto out_unlock;
524
525 err = security_msg_queue_msgctl(msq, cmd);
526 if (err)
527 goto out_unlock;
528
529 kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
530 tbuf.msg_stime = msq->q_stime;
531 tbuf.msg_rtime = msq->q_rtime;
532 tbuf.msg_ctime = msq->q_ctime;
533 tbuf.msg_cbytes = msq->q_cbytes;
534 tbuf.msg_qnum = msq->q_qnum;
535 tbuf.msg_qbytes = msq->q_qbytes;
536 tbuf.msg_lspid = msq->q_lspid;
537 tbuf.msg_lrpid = msq->q_lrpid;
538 rcu_read_unlock();
539
540 if (copy_msqid_to_user(buf, &tbuf, version))
541 return -EFAULT;
542 return success_return;
543 }
544
545 default:
546 return -EINVAL;
547 }
548
549 return err;
550out_unlock:
551 rcu_read_unlock();
552 return err;
553}
554
555SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
556{
557 int version;
558 struct ipc_namespace *ns;
559
560 if (msqid < 0 || cmd < 0)
561 return -EINVAL;
562
563 version = ipc_parse_version(&cmd);
564 ns = current->nsproxy->ipc_ns;
565
566 switch (cmd) {
567 case IPC_INFO:
568 case MSG_INFO:
569 case MSG_STAT:
570 case IPC_STAT:
571 return msgctl_nolock(ns, msqid, cmd, version, buf);
572 case IPC_SET:
573 case IPC_RMID:
574 return msgctl_down(ns, msqid, cmd, buf, version);
575 default:
576 return -EINVAL;
577 }
578}
579
580static int testmsg(struct msg_msg *msg, long type, int mode)
581{
582 switch (mode) {
583 case SEARCH_ANY:
584 case SEARCH_NUMBER:
585 return 1;
586 case SEARCH_LESSEQUAL:
587 if (msg->m_type <= type)
588 return 1;
589 break;
590 case SEARCH_EQUAL:
591 if (msg->m_type == type)
592 return 1;
593 break;
594 case SEARCH_NOTEQUAL:
595 if (msg->m_type != type)
596 return 1;
597 break;
598 }
599 return 0;
600}
601
602static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg,
603 struct wake_q_head *wake_q)
604{
605 struct msg_receiver *msr, *t;
606
607 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
608 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
609 !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
610 msr->r_msgtype, msr->r_mode)) {
611
612 list_del(&msr->r_list);
613 if (msr->r_maxsize < msg->m_ts) {
614 wake_q_add(wake_q, msr->r_tsk);
615 WRITE_ONCE(msr->r_msg, ERR_PTR(-E2BIG));
616 } else {
617 msq->q_lrpid = task_pid_vnr(msr->r_tsk);
618 msq->q_rtime = get_seconds();
619
620 wake_q_add(wake_q, msr->r_tsk);
621 WRITE_ONCE(msr->r_msg, msg);
622 return 1;
623 }
624 }
625 }
626
627 return 0;
628}
629
630long do_msgsnd(int msqid, long mtype, void __user *mtext,
631 size_t msgsz, int msgflg)
632{
633 struct msg_queue *msq;
634 struct msg_msg *msg;
635 int err;
636 struct ipc_namespace *ns;
637 WAKE_Q(wake_q);
638
639 ns = current->nsproxy->ipc_ns;
640
641 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
642 return -EINVAL;
643 if (mtype < 1)
644 return -EINVAL;
645
646 msg = load_msg(mtext, msgsz);
647 if (IS_ERR(msg))
648 return PTR_ERR(msg);
649
650 msg->m_type = mtype;
651 msg->m_ts = msgsz;
652
653 rcu_read_lock();
654 msq = msq_obtain_object_check(ns, msqid);
655 if (IS_ERR(msq)) {
656 err = PTR_ERR(msq);
657 goto out_unlock1;
658 }
659
660 ipc_lock_object(&msq->q_perm);
661
662 for (;;) {
663 struct msg_sender s;
664
665 err = -EACCES;
666 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
667 goto out_unlock0;
668
669
670 if (!ipc_valid_object(&msq->q_perm)) {
671 err = -EIDRM;
672 goto out_unlock0;
673 }
674
675 err = security_msg_queue_msgsnd(msq, msg, msgflg);
676 if (err)
677 goto out_unlock0;
678
679 if (msg_fits_inqueue(msq, msgsz))
680 break;
681
682
683 if (msgflg & IPC_NOWAIT) {
684 err = -EAGAIN;
685 goto out_unlock0;
686 }
687
688
689 ss_add(msq, &s, msgsz);
690
691 if (!ipc_rcu_getref(msq)) {
692 err = -EIDRM;
693 goto out_unlock0;
694 }
695
696 ipc_unlock_object(&msq->q_perm);
697 rcu_read_unlock();
698 schedule();
699
700 rcu_read_lock();
701 ipc_lock_object(&msq->q_perm);
702
703 ipc_rcu_putref(msq, msg_rcu_free);
704
705 if (!ipc_valid_object(&msq->q_perm)) {
706 err = -EIDRM;
707 goto out_unlock0;
708 }
709 ss_del(&s);
710
711 if (signal_pending(current)) {
712 err = -ERESTARTNOHAND;
713 goto out_unlock0;
714 }
715
716 }
717
718 msq->q_lspid = task_tgid_vnr(current);
719 msq->q_stime = get_seconds();
720
721 if (!pipelined_send(msq, msg, &wake_q)) {
722
723 list_add_tail(&msg->m_list, &msq->q_messages);
724 msq->q_cbytes += msgsz;
725 msq->q_qnum++;
726 atomic_add(msgsz, &ns->msg_bytes);
727 atomic_inc(&ns->msg_hdrs);
728 }
729
730 err = 0;
731 msg = NULL;
732
733out_unlock0:
734 ipc_unlock_object(&msq->q_perm);
735 wake_up_q(&wake_q);
736out_unlock1:
737 rcu_read_unlock();
738 if (msg != NULL)
739 free_msg(msg);
740 return err;
741}
742
743SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
744 int, msgflg)
745{
746 long mtype;
747
748 if (get_user(mtype, &msgp->mtype))
749 return -EFAULT;
750 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
751}
752
753static inline int convert_mode(long *msgtyp, int msgflg)
754{
755 if (msgflg & MSG_COPY)
756 return SEARCH_NUMBER;
757
758
759
760
761
762
763 if (*msgtyp == 0)
764 return SEARCH_ANY;
765 if (*msgtyp < 0) {
766 *msgtyp = -*msgtyp;
767 return SEARCH_LESSEQUAL;
768 }
769 if (msgflg & MSG_EXCEPT)
770 return SEARCH_NOTEQUAL;
771 return SEARCH_EQUAL;
772}
773
774static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
775{
776 struct msgbuf __user *msgp = dest;
777 size_t msgsz;
778
779 if (put_user(msg->m_type, &msgp->mtype))
780 return -EFAULT;
781
782 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
783 if (store_msg(msgp->mtext, msg, msgsz))
784 return -EFAULT;
785 return msgsz;
786}
787
788#ifdef CONFIG_CHECKPOINT_RESTORE
789
790
791
792
793static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
794{
795 struct msg_msg *copy;
796
797
798
799
800 copy = load_msg(buf, bufsz);
801 if (!IS_ERR(copy))
802 copy->m_ts = bufsz;
803 return copy;
804}
805
806static inline void free_copy(struct msg_msg *copy)
807{
808 if (copy)
809 free_msg(copy);
810}
811#else
812static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
813{
814 return ERR_PTR(-ENOSYS);
815}
816
817static inline void free_copy(struct msg_msg *copy)
818{
819}
820#endif
821
822static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
823{
824 struct msg_msg *msg, *found = NULL;
825 long count = 0;
826
827 list_for_each_entry(msg, &msq->q_messages, m_list) {
828 if (testmsg(msg, *msgtyp, mode) &&
829 !security_msg_queue_msgrcv(msq, msg, current,
830 *msgtyp, mode)) {
831 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
832 *msgtyp = msg->m_type - 1;
833 found = msg;
834 } else if (mode == SEARCH_NUMBER) {
835 if (*msgtyp == count)
836 return msg;
837 } else
838 return msg;
839 count++;
840 }
841 }
842
843 return found ?: ERR_PTR(-EAGAIN);
844}
845
846long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg,
847 long (*msg_handler)(void __user *, struct msg_msg *, size_t))
848{
849 int mode;
850 struct msg_queue *msq;
851 struct ipc_namespace *ns;
852 struct msg_msg *msg, *copy = NULL;
853 WAKE_Q(wake_q);
854
855 ns = current->nsproxy->ipc_ns;
856
857 if (msqid < 0 || (long) bufsz < 0)
858 return -EINVAL;
859
860 if (msgflg & MSG_COPY) {
861 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
862 return -EINVAL;
863 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
864 if (IS_ERR(copy))
865 return PTR_ERR(copy);
866 }
867 mode = convert_mode(&msgtyp, msgflg);
868
869 rcu_read_lock();
870 msq = msq_obtain_object_check(ns, msqid);
871 if (IS_ERR(msq)) {
872 rcu_read_unlock();
873 free_copy(copy);
874 return PTR_ERR(msq);
875 }
876
877 for (;;) {
878 struct msg_receiver msr_d;
879
880 msg = ERR_PTR(-EACCES);
881 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
882 goto out_unlock1;
883
884 ipc_lock_object(&msq->q_perm);
885
886
887 if (!ipc_valid_object(&msq->q_perm)) {
888 msg = ERR_PTR(-EIDRM);
889 goto out_unlock0;
890 }
891
892 msg = find_msg(msq, &msgtyp, mode);
893 if (!IS_ERR(msg)) {
894
895
896
897
898 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
899 msg = ERR_PTR(-E2BIG);
900 goto out_unlock0;
901 }
902
903
904
905
906 if (msgflg & MSG_COPY) {
907 msg = copy_msg(msg, copy);
908 goto out_unlock0;
909 }
910
911 list_del(&msg->m_list);
912 msq->q_qnum--;
913 msq->q_rtime = get_seconds();
914 msq->q_lrpid = task_tgid_vnr(current);
915 msq->q_cbytes -= msg->m_ts;
916 atomic_sub(msg->m_ts, &ns->msg_bytes);
917 atomic_dec(&ns->msg_hdrs);
918 ss_wakeup(msq, &wake_q, false);
919
920 goto out_unlock0;
921 }
922
923
924 if (msgflg & IPC_NOWAIT) {
925 msg = ERR_PTR(-ENOMSG);
926 goto out_unlock0;
927 }
928
929 list_add_tail(&msr_d.r_list, &msq->q_receivers);
930 msr_d.r_tsk = current;
931 msr_d.r_msgtype = msgtyp;
932 msr_d.r_mode = mode;
933 if (msgflg & MSG_NOERROR)
934 msr_d.r_maxsize = INT_MAX;
935 else
936 msr_d.r_maxsize = bufsz;
937 msr_d.r_msg = ERR_PTR(-EAGAIN);
938 __set_current_state(TASK_INTERRUPTIBLE);
939
940 ipc_unlock_object(&msq->q_perm);
941 rcu_read_unlock();
942 schedule();
943
944
945
946
947
948
949
950
951
952
953 rcu_read_lock();
954
955
956
957
958
959
960
961
962
963
964
965 msg = READ_ONCE(msr_d.r_msg);
966 if (msg != ERR_PTR(-EAGAIN))
967 goto out_unlock1;
968
969
970
971
972
973 ipc_lock_object(&msq->q_perm);
974
975 msg = msr_d.r_msg;
976 if (msg != ERR_PTR(-EAGAIN))
977 goto out_unlock0;
978
979 list_del(&msr_d.r_list);
980 if (signal_pending(current)) {
981 msg = ERR_PTR(-ERESTARTNOHAND);
982 goto out_unlock0;
983 }
984
985 ipc_unlock_object(&msq->q_perm);
986 }
987
988out_unlock0:
989 ipc_unlock_object(&msq->q_perm);
990 wake_up_q(&wake_q);
991out_unlock1:
992 rcu_read_unlock();
993 if (IS_ERR(msg)) {
994 free_copy(copy);
995 return PTR_ERR(msg);
996 }
997
998 bufsz = msg_handler(buf, msg, bufsz);
999 free_msg(msg);
1000
1001 return bufsz;
1002}
1003
1004SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
1005 long, msgtyp, int, msgflg)
1006{
1007 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
1008}
1009
1010
1011void msg_init_ns(struct ipc_namespace *ns)
1012{
1013 ns->msg_ctlmax = MSGMAX;
1014 ns->msg_ctlmnb = MSGMNB;
1015 ns->msg_ctlmni = MSGMNI;
1016
1017 atomic_set(&ns->msg_bytes, 0);
1018 atomic_set(&ns->msg_hdrs, 0);
1019 ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
1020}
1021
1022#ifdef CONFIG_IPC_NS
1023void msg_exit_ns(struct ipc_namespace *ns)
1024{
1025 free_ipcs(ns, &msg_ids(ns), freeque);
1026 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
1027}
1028#endif
1029
1030#ifdef CONFIG_PROC_FS
1031static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
1032{
1033 struct user_namespace *user_ns = seq_user_ns(s);
1034 struct msg_queue *msq = it;
1035
1036 seq_printf(s,
1037 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
1038 msq->q_perm.key,
1039 msq->q_perm.id,
1040 msq->q_perm.mode,
1041 msq->q_cbytes,
1042 msq->q_qnum,
1043 msq->q_lspid,
1044 msq->q_lrpid,
1045 from_kuid_munged(user_ns, msq->q_perm.uid),
1046 from_kgid_munged(user_ns, msq->q_perm.gid),
1047 from_kuid_munged(user_ns, msq->q_perm.cuid),
1048 from_kgid_munged(user_ns, msq->q_perm.cgid),
1049 msq->q_stime,
1050 msq->q_rtime,
1051 msq->q_ctime);
1052
1053 return 0;
1054}
1055#endif
1056
1057void __init msg_init(void)
1058{
1059 msg_init_ns(&init_ipc_ns);
1060
1061 ipc_init_proc_interface("sysvipc/msg",
1062 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
1063 IPC_MSG_IDS, sysvipc_msg_proc_show);
1064}
1065