Line data Source code
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 */
48 : struct 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 */
75 : struct 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 */
87 : struct 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 :
101 0 : static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
102 : {
103 0 : struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&msg_ids(ns), id);
104 :
105 0 : if (IS_ERR(ipcp))
106 : return ERR_CAST(ipcp);
107 :
108 0 : return container_of(ipcp, struct msg_queue, q_perm);
109 : }
110 :
111 0 : static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
112 : int id)
113 : {
114 0 : struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
115 :
116 0 : if (IS_ERR(ipcp))
117 : return ERR_CAST(ipcp);
118 :
119 0 : return container_of(ipcp, struct msg_queue, q_perm);
120 : }
121 :
122 0 : static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
123 : {
124 0 : ipc_rmid(&msg_ids(ns), &s->q_perm);
125 : }
126 :
127 0 : static void msg_rcu_free(struct rcu_head *head)
128 : {
129 0 : struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
130 0 : struct msg_queue *msq = container_of(p, struct msg_queue, q_perm);
131 :
132 0 : security_msg_queue_free(&msq->q_perm);
133 0 : kvfree(msq);
134 0 : }
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 : */
143 0 : static int newque(struct ipc_namespace *ns, struct ipc_params *params)
144 : {
145 0 : struct msg_queue *msq;
146 0 : int retval;
147 0 : key_t key = params->key;
148 0 : int msgflg = params->flg;
149 :
150 0 : msq = kvmalloc(sizeof(*msq), GFP_KERNEL);
151 0 : if (unlikely(!msq))
152 : return -ENOMEM;
153 :
154 0 : msq->q_perm.mode = msgflg & S_IRWXUGO;
155 0 : msq->q_perm.key = key;
156 :
157 0 : msq->q_perm.security = NULL;
158 0 : retval = security_msg_queue_alloc(&msq->q_perm);
159 0 : if (retval) {
160 0 : kvfree(msq);
161 0 : return retval;
162 : }
163 :
164 0 : msq->q_stime = msq->q_rtime = 0;
165 0 : msq->q_ctime = ktime_get_real_seconds();
166 0 : msq->q_cbytes = msq->q_qnum = 0;
167 0 : msq->q_qbytes = ns->msg_ctlmnb;
168 0 : msq->q_lspid = msq->q_lrpid = NULL;
169 0 : INIT_LIST_HEAD(&msq->q_messages);
170 0 : INIT_LIST_HEAD(&msq->q_receivers);
171 0 : INIT_LIST_HEAD(&msq->q_senders);
172 :
173 : /* ipc_addid() locks msq upon success. */
174 0 : retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
175 0 : if (retval < 0) {
176 0 : ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
177 0 : return retval;
178 : }
179 :
180 0 : ipc_unlock_object(&msq->q_perm);
181 0 : rcu_read_unlock();
182 :
183 0 : return msq->q_perm.id;
184 : }
185 :
186 0 : static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz)
187 : {
188 0 : return msgsz + msq->q_cbytes <= msq->q_qbytes &&
189 0 : 1 + msq->q_qnum <= msq->q_qbytes;
190 : }
191 :
192 0 : static inline void ss_add(struct msg_queue *msq,
193 : struct msg_sender *mss, size_t msgsz)
194 : {
195 0 : mss->tsk = current;
196 0 : 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 0 : __set_current_state(TASK_INTERRUPTIBLE);
202 0 : list_add_tail(&mss->list, &msq->q_senders);
203 : }
204 :
205 0 : static inline void ss_del(struct msg_sender *mss)
206 : {
207 0 : if (mss->list.next)
208 0 : list_del(&mss->list);
209 : }
210 :
211 0 : static void ss_wakeup(struct msg_queue *msq,
212 : struct wake_q_head *wake_q, bool kill)
213 : {
214 0 : struct msg_sender *mss, *t;
215 0 : struct task_struct *stop_tsk = NULL;
216 0 : struct list_head *h = &msq->q_senders;
217 :
218 0 : list_for_each_entry_safe(mss, t, h, list) {
219 0 : if (kill)
220 0 : 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 0 : 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 0 : else if (!msg_fits_inqueue(msq, mss->msgsz)) {
237 0 : if (!stop_tsk)
238 0 : stop_tsk = mss->tsk;
239 :
240 0 : list_move_tail(&mss->list, &msq->q_senders);
241 0 : continue;
242 : }
243 :
244 0 : wake_q_add(wake_q, mss->tsk);
245 : }
246 0 : }
247 :
248 0 : static void expunge_all(struct msg_queue *msq, int res,
249 : struct wake_q_head *wake_q)
250 : {
251 0 : struct msg_receiver *msr, *t;
252 :
253 0 : list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
254 0 : get_task_struct(msr->r_tsk);
255 :
256 : /* see MSG_BARRIER for purpose/pairing */
257 0 : smp_store_release(&msr->r_msg, ERR_PTR(res));
258 0 : wake_q_add_safe(wake_q, msr->r_tsk);
259 : }
260 0 : }
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 : */
270 0 : static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
271 : __releases(RCU)
272 : __releases(&msq->q_perm)
273 : {
274 0 : struct msg_msg *msg, *t;
275 0 : struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
276 0 : DEFINE_WAKE_Q(wake_q);
277 :
278 0 : expunge_all(msq, -EIDRM, &wake_q);
279 0 : ss_wakeup(msq, &wake_q, true);
280 0 : msg_rmid(ns, msq);
281 0 : ipc_unlock_object(&msq->q_perm);
282 0 : wake_up_q(&wake_q);
283 0 : rcu_read_unlock();
284 :
285 0 : list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
286 0 : atomic_dec(&ns->msg_hdrs);
287 0 : free_msg(msg);
288 : }
289 0 : atomic_sub(msq->q_cbytes, &ns->msg_bytes);
290 0 : ipc_update_pid(&msq->q_lspid, NULL);
291 0 : ipc_update_pid(&msq->q_lrpid, NULL);
292 0 : ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
293 0 : }
294 :
295 0 : long ksys_msgget(key_t key, int msgflg)
296 : {
297 0 : struct ipc_namespace *ns;
298 0 : static const struct ipc_ops msg_ops = {
299 : .getnew = newque,
300 : .associate = security_msg_queue_associate,
301 : };
302 0 : struct ipc_params msg_params;
303 :
304 0 : ns = current->nsproxy->ipc_ns;
305 :
306 0 : msg_params.key = key;
307 0 : msg_params.flg = msgflg;
308 :
309 0 : return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
310 : }
311 :
312 0 : SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
313 : {
314 0 : return ksys_msgget(key, msgflg);
315 : }
316 :
317 : static inline unsigned long
318 0 : copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
319 : {
320 0 : switch (version) {
321 : case IPC_64:
322 0 : return copy_to_user(buf, in, sizeof(*in));
323 0 : case IPC_OLD:
324 : {
325 0 : struct msqid_ds out;
326 :
327 0 : memset(&out, 0, sizeof(out));
328 :
329 0 : ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
330 :
331 0 : out.msg_stime = in->msg_stime;
332 0 : out.msg_rtime = in->msg_rtime;
333 0 : out.msg_ctime = in->msg_ctime;
334 :
335 0 : if (in->msg_cbytes > USHRT_MAX)
336 0 : out.msg_cbytes = USHRT_MAX;
337 : else
338 0 : out.msg_cbytes = in->msg_cbytes;
339 0 : out.msg_lcbytes = in->msg_cbytes;
340 :
341 0 : if (in->msg_qnum > USHRT_MAX)
342 0 : out.msg_qnum = USHRT_MAX;
343 : else
344 0 : out.msg_qnum = in->msg_qnum;
345 :
346 0 : if (in->msg_qbytes > USHRT_MAX)
347 0 : out.msg_qbytes = USHRT_MAX;
348 : else
349 0 : out.msg_qbytes = in->msg_qbytes;
350 0 : out.msg_lqbytes = in->msg_qbytes;
351 :
352 0 : out.msg_lspid = in->msg_lspid;
353 0 : out.msg_lrpid = in->msg_lrpid;
354 :
355 0 : return copy_to_user(buf, &out, sizeof(out));
356 : }
357 : default:
358 : return -EINVAL;
359 : }
360 : }
361 :
362 : static inline unsigned long
363 0 : copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
364 : {
365 0 : switch (version) {
366 : case IPC_64:
367 0 : if (copy_from_user(out, buf, sizeof(*out)))
368 0 : return -EFAULT;
369 : return 0;
370 : case IPC_OLD:
371 : {
372 0 : struct msqid_ds tbuf_old;
373 :
374 0 : if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
375 : return -EFAULT;
376 :
377 0 : out->msg_perm.uid = tbuf_old.msg_perm.uid;
378 0 : out->msg_perm.gid = tbuf_old.msg_perm.gid;
379 0 : out->msg_perm.mode = tbuf_old.msg_perm.mode;
380 :
381 0 : if (tbuf_old.msg_qbytes == 0)
382 0 : out->msg_qbytes = tbuf_old.msg_lqbytes;
383 : else
384 0 : 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 : */
398 0 : static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
399 : struct ipc64_perm *perm, int msg_qbytes)
400 : {
401 0 : struct kern_ipc_perm *ipcp;
402 0 : struct msg_queue *msq;
403 0 : int err;
404 :
405 0 : down_write(&msg_ids(ns).rwsem);
406 0 : rcu_read_lock();
407 :
408 0 : ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd,
409 : perm, msg_qbytes);
410 0 : if (IS_ERR(ipcp)) {
411 0 : err = PTR_ERR(ipcp);
412 0 : goto out_unlock1;
413 : }
414 :
415 0 : msq = container_of(ipcp, struct msg_queue, q_perm);
416 :
417 0 : err = security_msg_queue_msgctl(&msq->q_perm, cmd);
418 0 : if (err)
419 0 : goto out_unlock1;
420 :
421 0 : switch (cmd) {
422 0 : case IPC_RMID:
423 0 : ipc_lock_object(&msq->q_perm);
424 : /* freeque unlocks the ipc object and rcu */
425 0 : freeque(ns, ipcp);
426 0 : goto out_up;
427 0 : case IPC_SET:
428 : {
429 0 : DEFINE_WAKE_Q(wake_q);
430 :
431 0 : if (msg_qbytes > ns->msg_ctlmnb &&
432 0 : !capable(CAP_SYS_RESOURCE)) {
433 0 : err = -EPERM;
434 0 : goto out_unlock1;
435 : }
436 :
437 0 : ipc_lock_object(&msq->q_perm);
438 0 : err = ipc_update_perm(perm, ipcp);
439 0 : if (err)
440 0 : goto out_unlock0;
441 :
442 0 : msq->q_qbytes = msg_qbytes;
443 :
444 0 : msq->q_ctime = ktime_get_real_seconds();
445 : /*
446 : * Sleeping receivers might be excluded by
447 : * stricter permissions.
448 : */
449 0 : expunge_all(msq, -EAGAIN, &wake_q);
450 : /*
451 : * Sleeping senders might be able to send
452 : * due to a larger queue size.
453 : */
454 0 : ss_wakeup(msq, &wake_q, false);
455 0 : ipc_unlock_object(&msq->q_perm);
456 0 : wake_up_q(&wake_q);
457 :
458 0 : goto out_unlock1;
459 : }
460 0 : default:
461 0 : err = -EINVAL;
462 0 : goto out_unlock1;
463 : }
464 :
465 0 : out_unlock0:
466 0 : ipc_unlock_object(&msq->q_perm);
467 0 : out_unlock1:
468 0 : rcu_read_unlock();
469 0 : out_up:
470 0 : up_write(&msg_ids(ns).rwsem);
471 0 : return err;
472 : }
473 :
474 0 : static int msgctl_info(struct ipc_namespace *ns, int msqid,
475 : int cmd, struct msginfo *msginfo)
476 : {
477 0 : int err;
478 0 : 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 0 : err = security_msg_queue_msgctl(NULL, cmd);
486 0 : if (err)
487 : return err;
488 :
489 0 : memset(msginfo, 0, sizeof(*msginfo));
490 0 : msginfo->msgmni = ns->msg_ctlmni;
491 0 : msginfo->msgmax = ns->msg_ctlmax;
492 0 : msginfo->msgmnb = ns->msg_ctlmnb;
493 0 : msginfo->msgssz = MSGSSZ;
494 0 : msginfo->msgseg = MSGSEG;
495 0 : down_read(&msg_ids(ns).rwsem);
496 0 : if (cmd == MSG_INFO) {
497 0 : msginfo->msgpool = msg_ids(ns).in_use;
498 0 : msginfo->msgmap = atomic_read(&ns->msg_hdrs);
499 0 : msginfo->msgtql = atomic_read(&ns->msg_bytes);
500 : } else {
501 0 : msginfo->msgmap = MSGMAP;
502 0 : msginfo->msgpool = MSGPOOL;
503 0 : msginfo->msgtql = MSGTQL;
504 : }
505 0 : max_idx = ipc_get_maxidx(&msg_ids(ns));
506 0 : up_read(&msg_ids(ns).rwsem);
507 0 : return (max_idx < 0) ? 0 : max_idx;
508 : }
509 :
510 0 : static int msgctl_stat(struct ipc_namespace *ns, int msqid,
511 : int cmd, struct msqid64_ds *p)
512 : {
513 0 : struct msg_queue *msq;
514 0 : int err;
515 :
516 0 : memset(p, 0, sizeof(*p));
517 :
518 0 : rcu_read_lock();
519 0 : if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) {
520 0 : msq = msq_obtain_object(ns, msqid);
521 0 : if (IS_ERR(msq)) {
522 0 : err = PTR_ERR(msq);
523 0 : goto out_unlock;
524 : }
525 : } else { /* IPC_STAT */
526 0 : msq = msq_obtain_object_check(ns, msqid);
527 0 : if (IS_ERR(msq)) {
528 0 : err = PTR_ERR(msq);
529 0 : goto out_unlock;
530 : }
531 : }
532 :
533 : /* see comment for SHM_STAT_ANY */
534 0 : if (cmd == MSG_STAT_ANY)
535 0 : audit_ipc_obj(&msq->q_perm);
536 : else {
537 0 : err = -EACCES;
538 0 : if (ipcperms(ns, &msq->q_perm, S_IRUGO))
539 0 : goto out_unlock;
540 : }
541 :
542 0 : err = security_msg_queue_msgctl(&msq->q_perm, cmd);
543 0 : if (err)
544 0 : goto out_unlock;
545 :
546 0 : ipc_lock_object(&msq->q_perm);
547 :
548 0 : if (!ipc_valid_object(&msq->q_perm)) {
549 0 : ipc_unlock_object(&msq->q_perm);
550 0 : err = -EIDRM;
551 0 : goto out_unlock;
552 : }
553 :
554 0 : kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm);
555 0 : p->msg_stime = msq->q_stime;
556 0 : p->msg_rtime = msq->q_rtime;
557 0 : 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 0 : p->msg_cbytes = msq->q_cbytes;
564 0 : p->msg_qnum = msq->q_qnum;
565 0 : p->msg_qbytes = msq->q_qbytes;
566 0 : p->msg_lspid = pid_vnr(msq->q_lspid);
567 0 : p->msg_lrpid = pid_vnr(msq->q_lrpid);
568 :
569 0 : 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 0 : err = msq->q_perm.id;
581 : }
582 :
583 0 : ipc_unlock_object(&msq->q_perm);
584 0 : out_unlock:
585 0 : rcu_read_unlock();
586 0 : return err;
587 : }
588 :
589 0 : static long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf, int version)
590 : {
591 0 : struct ipc_namespace *ns;
592 0 : struct msqid64_ds msqid64;
593 0 : int err;
594 :
595 0 : if (msqid < 0 || cmd < 0)
596 : return -EINVAL;
597 :
598 0 : ns = current->nsproxy->ipc_ns;
599 :
600 0 : switch (cmd) {
601 0 : case IPC_INFO:
602 : case MSG_INFO: {
603 0 : struct msginfo msginfo;
604 0 : err = msgctl_info(ns, msqid, cmd, &msginfo);
605 0 : if (err < 0)
606 0 : return err;
607 0 : if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
608 0 : err = -EFAULT;
609 0 : return err;
610 : }
611 0 : case MSG_STAT: /* msqid is an index rather than a msg queue id */
612 : case MSG_STAT_ANY:
613 : case IPC_STAT:
614 0 : err = msgctl_stat(ns, msqid, cmd, &msqid64);
615 0 : if (err < 0)
616 0 : return err;
617 0 : if (copy_msqid_to_user(buf, &msqid64, version))
618 0 : err = -EFAULT;
619 0 : return err;
620 0 : case IPC_SET:
621 0 : if (copy_msqid_from_user(&msqid64, buf, version))
622 : return -EFAULT;
623 0 : return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm,
624 0 : msqid64.msg_qbytes);
625 0 : case IPC_RMID:
626 0 : return msgctl_down(ns, msqid, cmd, NULL, 0);
627 : default:
628 : return -EINVAL;
629 : }
630 : }
631 :
632 0 : SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
633 : {
634 0 : return ksys_msgctl(msqid, cmd, buf, IPC_64);
635 : }
636 :
637 : #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
638 : long 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 :
645 : SYSCALL_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 :
653 : struct 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 :
669 0 : static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf,
670 : int version)
671 : {
672 0 : memset(out, 0, sizeof(*out));
673 0 : if (version == IPC_64) {
674 0 : struct compat_msqid64_ds __user *p = buf;
675 0 : if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm))
676 : return -EFAULT;
677 0 : if (get_user(out->msg_qbytes, &p->msg_qbytes))
678 0 : return -EFAULT;
679 : } else {
680 0 : struct compat_msqid_ds __user *p = buf;
681 0 : if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm))
682 : return -EFAULT;
683 0 : if (get_user(out->msg_qbytes, &p->msg_qbytes))
684 0 : return -EFAULT;
685 : }
686 : return 0;
687 : }
688 :
689 0 : static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in,
690 : int version)
691 : {
692 0 : if (version == IPC_64) {
693 0 : struct compat_msqid64_ds v;
694 0 : memset(&v, 0, sizeof(v));
695 0 : to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm);
696 0 : v.msg_stime = lower_32_bits(in->msg_stime);
697 0 : v.msg_stime_high = upper_32_bits(in->msg_stime);
698 0 : v.msg_rtime = lower_32_bits(in->msg_rtime);
699 0 : v.msg_rtime_high = upper_32_bits(in->msg_rtime);
700 0 : v.msg_ctime = lower_32_bits(in->msg_ctime);
701 0 : v.msg_ctime_high = upper_32_bits(in->msg_ctime);
702 0 : v.msg_cbytes = in->msg_cbytes;
703 0 : v.msg_qnum = in->msg_qnum;
704 0 : v.msg_qbytes = in->msg_qbytes;
705 0 : v.msg_lspid = in->msg_lspid;
706 0 : v.msg_lrpid = in->msg_lrpid;
707 0 : return copy_to_user(buf, &v, sizeof(v));
708 : } else {
709 0 : struct compat_msqid_ds v;
710 0 : memset(&v, 0, sizeof(v));
711 0 : to_compat_ipc_perm(&v.msg_perm, &in->msg_perm);
712 0 : v.msg_stime = in->msg_stime;
713 0 : v.msg_rtime = in->msg_rtime;
714 0 : v.msg_ctime = in->msg_ctime;
715 0 : v.msg_cbytes = in->msg_cbytes;
716 0 : v.msg_qnum = in->msg_qnum;
717 0 : v.msg_qbytes = in->msg_qbytes;
718 0 : v.msg_lspid = in->msg_lspid;
719 0 : v.msg_lrpid = in->msg_lrpid;
720 0 : return copy_to_user(buf, &v, sizeof(v));
721 : }
722 : }
723 :
724 0 : static long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr, int version)
725 : {
726 0 : struct ipc_namespace *ns;
727 0 : int err;
728 0 : struct msqid64_ds msqid64;
729 :
730 0 : ns = current->nsproxy->ipc_ns;
731 :
732 0 : if (msqid < 0 || cmd < 0)
733 : return -EINVAL;
734 :
735 0 : switch (cmd & (~IPC_64)) {
736 0 : case IPC_INFO:
737 : case MSG_INFO: {
738 0 : struct msginfo msginfo;
739 0 : err = msgctl_info(ns, msqid, cmd, &msginfo);
740 0 : if (err < 0)
741 0 : return err;
742 0 : if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo)))
743 0 : err = -EFAULT;
744 0 : return err;
745 : }
746 0 : case IPC_STAT:
747 : case MSG_STAT:
748 : case MSG_STAT_ANY:
749 0 : err = msgctl_stat(ns, msqid, cmd, &msqid64);
750 0 : if (err < 0)
751 0 : return err;
752 0 : if (copy_compat_msqid_to_user(uptr, &msqid64, version))
753 0 : err = -EFAULT;
754 0 : return err;
755 0 : case IPC_SET:
756 0 : if (copy_compat_msqid_from_user(&msqid64, uptr, version))
757 : return -EFAULT;
758 0 : return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes);
759 0 : case IPC_RMID:
760 0 : return msgctl_down(ns, msqid, cmd, NULL, 0);
761 : default:
762 : return -EINVAL;
763 : }
764 : }
765 :
766 0 : COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)
767 : {
768 0 : return compat_ksys_msgctl(msqid, cmd, uptr, IPC_64);
769 : }
770 :
771 : #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
772 0 : long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr)
773 : {
774 0 : int version = compat_ipc_parse_version(&cmd);
775 :
776 0 : return compat_ksys_msgctl(msqid, cmd, uptr, version);
777 : }
778 :
779 0 : COMPAT_SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, void __user *, uptr)
780 : {
781 0 : return compat_ksys_old_msgctl(msqid, cmd, uptr);
782 : }
783 : #endif
784 : #endif
785 :
786 0 : static int testmsg(struct msg_msg *msg, long type, int mode)
787 : {
788 0 : switch (mode) {
789 : case SEARCH_ANY:
790 : case SEARCH_NUMBER:
791 : return 1;
792 0 : case SEARCH_LESSEQUAL:
793 0 : if (msg->m_type <= type)
794 : return 1;
795 : break;
796 0 : case SEARCH_EQUAL:
797 0 : if (msg->m_type == type)
798 : return 1;
799 : break;
800 0 : case SEARCH_NOTEQUAL:
801 0 : if (msg->m_type != type)
802 : return 1;
803 : break;
804 : }
805 0 : return 0;
806 : }
807 :
808 0 : static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg,
809 : struct wake_q_head *wake_q)
810 : {
811 0 : struct msg_receiver *msr, *t;
812 :
813 0 : list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
814 0 : if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
815 0 : !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk,
816 : msr->r_msgtype, msr->r_mode)) {
817 :
818 0 : list_del(&msr->r_list);
819 0 : if (msr->r_maxsize < msg->m_ts) {
820 0 : wake_q_add(wake_q, msr->r_tsk);
821 :
822 : /* See expunge_all regarding memory barrier */
823 0 : smp_store_release(&msr->r_msg, ERR_PTR(-E2BIG));
824 : } else {
825 0 : ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk));
826 0 : msq->q_rtime = ktime_get_real_seconds();
827 :
828 0 : wake_q_add(wake_q, msr->r_tsk);
829 :
830 : /* See expunge_all regarding memory barrier */
831 0 : smp_store_release(&msr->r_msg, msg);
832 0 : return 1;
833 : }
834 : }
835 : }
836 :
837 : return 0;
838 : }
839 :
840 0 : static long do_msgsnd(int msqid, long mtype, void __user *mtext,
841 : size_t msgsz, int msgflg)
842 : {
843 0 : struct msg_queue *msq;
844 0 : struct msg_msg *msg;
845 0 : int err;
846 0 : struct ipc_namespace *ns;
847 0 : DEFINE_WAKE_Q(wake_q);
848 :
849 0 : ns = current->nsproxy->ipc_ns;
850 :
851 0 : if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
852 : return -EINVAL;
853 0 : if (mtype < 1)
854 : return -EINVAL;
855 :
856 0 : msg = load_msg(mtext, msgsz);
857 0 : if (IS_ERR(msg))
858 0 : return PTR_ERR(msg);
859 :
860 0 : msg->m_type = mtype;
861 0 : msg->m_ts = msgsz;
862 :
863 0 : rcu_read_lock();
864 0 : msq = msq_obtain_object_check(ns, msqid);
865 0 : if (IS_ERR(msq)) {
866 0 : err = PTR_ERR(msq);
867 0 : goto out_unlock1;
868 : }
869 :
870 0 : ipc_lock_object(&msq->q_perm);
871 :
872 0 : for (;;) {
873 0 : struct msg_sender s;
874 :
875 0 : err = -EACCES;
876 0 : if (ipcperms(ns, &msq->q_perm, S_IWUGO))
877 0 : goto out_unlock0;
878 :
879 : /* raced with RMID? */
880 0 : if (!ipc_valid_object(&msq->q_perm)) {
881 0 : err = -EIDRM;
882 0 : goto out_unlock0;
883 : }
884 :
885 0 : err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg);
886 0 : if (err)
887 0 : goto out_unlock0;
888 :
889 0 : if (msg_fits_inqueue(msq, msgsz))
890 : break;
891 :
892 : /* queue full, wait: */
893 0 : if (msgflg & IPC_NOWAIT) {
894 0 : err = -EAGAIN;
895 0 : goto out_unlock0;
896 : }
897 :
898 : /* enqueue the sender and prepare to block */
899 0 : ss_add(msq, &s, msgsz);
900 :
901 0 : if (!ipc_rcu_getref(&msq->q_perm)) {
902 0 : err = -EIDRM;
903 0 : goto out_unlock0;
904 : }
905 :
906 0 : ipc_unlock_object(&msq->q_perm);
907 0 : rcu_read_unlock();
908 0 : schedule();
909 :
910 0 : rcu_read_lock();
911 0 : ipc_lock_object(&msq->q_perm);
912 :
913 0 : ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
914 : /* raced with RMID? */
915 0 : if (!ipc_valid_object(&msq->q_perm)) {
916 0 : err = -EIDRM;
917 0 : goto out_unlock0;
918 : }
919 0 : ss_del(&s);
920 :
921 0 : if (signal_pending(current)) {
922 0 : err = -ERESTARTNOHAND;
923 0 : goto out_unlock0;
924 : }
925 :
926 : }
927 :
928 0 : ipc_update_pid(&msq->q_lspid, task_tgid(current));
929 0 : msq->q_stime = ktime_get_real_seconds();
930 :
931 0 : if (!pipelined_send(msq, msg, &wake_q)) {
932 : /* no one is waiting for this message, enqueue it */
933 0 : list_add_tail(&msg->m_list, &msq->q_messages);
934 0 : msq->q_cbytes += msgsz;
935 0 : msq->q_qnum++;
936 0 : atomic_add(msgsz, &ns->msg_bytes);
937 0 : atomic_inc(&ns->msg_hdrs);
938 : }
939 :
940 : err = 0;
941 : msg = NULL;
942 :
943 0 : out_unlock0:
944 0 : ipc_unlock_object(&msq->q_perm);
945 0 : wake_up_q(&wake_q);
946 0 : out_unlock1:
947 0 : rcu_read_unlock();
948 0 : if (msg != NULL)
949 0 : free_msg(msg);
950 0 : return err;
951 : }
952 :
953 0 : long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
954 : int msgflg)
955 : {
956 0 : long mtype;
957 :
958 0 : if (get_user(mtype, &msgp->mtype))
959 : return -EFAULT;
960 0 : return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
961 : }
962 :
963 0 : SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
964 : int, msgflg)
965 : {
966 0 : return ksys_msgsnd(msqid, msgp, msgsz, msgflg);
967 : }
968 :
969 : #ifdef CONFIG_COMPAT
970 :
971 : struct compat_msgbuf {
972 : compat_long_t mtype;
973 : char mtext[1];
974 : };
975 :
976 0 : long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
977 : compat_ssize_t msgsz, int msgflg)
978 : {
979 0 : struct compat_msgbuf __user *up = compat_ptr(msgp);
980 0 : compat_long_t mtype;
981 :
982 0 : if (get_user(mtype, &up->mtype))
983 : return -EFAULT;
984 0 : return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg);
985 : }
986 :
987 0 : COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
988 : compat_ssize_t, msgsz, int, msgflg)
989 : {
990 0 : return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg);
991 : }
992 : #endif
993 :
994 0 : static inline int convert_mode(long *msgtyp, int msgflg)
995 : {
996 0 : 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 0 : if (*msgtyp == 0)
1005 : return SEARCH_ANY;
1006 0 : if (*msgtyp < 0) {
1007 0 : if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */
1008 0 : *msgtyp = LONG_MAX;
1009 : else
1010 0 : *msgtyp = -*msgtyp;
1011 0 : return SEARCH_LESSEQUAL;
1012 : }
1013 0 : if (msgflg & MSG_EXCEPT)
1014 0 : return SEARCH_NOTEQUAL;
1015 : return SEARCH_EQUAL;
1016 : }
1017 :
1018 0 : static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
1019 : {
1020 0 : struct msgbuf __user *msgp = dest;
1021 0 : size_t msgsz;
1022 :
1023 0 : if (put_user(msg->m_type, &msgp->mtype))
1024 : return -EFAULT;
1025 :
1026 0 : msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
1027 0 : if (store_msg(msgp->mtext, msg, msgsz))
1028 : return -EFAULT;
1029 0 : 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 : */
1037 : static 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 :
1050 : static inline void free_copy(struct msg_msg *copy)
1051 : {
1052 : if (copy)
1053 : free_msg(copy);
1054 : }
1055 : #else
1056 0 : static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
1057 : {
1058 0 : return ERR_PTR(-ENOSYS);
1059 : }
1060 :
1061 0 : static inline void free_copy(struct msg_msg *copy)
1062 : {
1063 0 : }
1064 : #endif
1065 :
1066 0 : static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
1067 : {
1068 0 : struct msg_msg *msg, *found = NULL;
1069 0 : long count = 0;
1070 :
1071 0 : list_for_each_entry(msg, &msq->q_messages, m_list) {
1072 0 : if (testmsg(msg, *msgtyp, mode) &&
1073 0 : !security_msg_queue_msgrcv(&msq->q_perm, msg, current,
1074 : *msgtyp, mode)) {
1075 0 : if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
1076 0 : *msgtyp = msg->m_type - 1;
1077 0 : found = msg;
1078 0 : } else if (mode == SEARCH_NUMBER) {
1079 0 : if (*msgtyp == count)
1080 0 : return msg;
1081 : } else
1082 0 : return msg;
1083 0 : count++;
1084 : }
1085 : }
1086 :
1087 0 : return found ?: ERR_PTR(-EAGAIN);
1088 : }
1089 :
1090 0 : static 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 0 : int mode;
1094 0 : struct msg_queue *msq;
1095 0 : struct ipc_namespace *ns;
1096 0 : struct msg_msg *msg, *copy = NULL;
1097 0 : DEFINE_WAKE_Q(wake_q);
1098 :
1099 0 : ns = current->nsproxy->ipc_ns;
1100 :
1101 0 : if (msqid < 0 || (long) bufsz < 0)
1102 : return -EINVAL;
1103 :
1104 0 : if (msgflg & MSG_COPY) {
1105 0 : if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
1106 : return -EINVAL;
1107 0 : copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
1108 0 : if (IS_ERR(copy))
1109 0 : return PTR_ERR(copy);
1110 : }
1111 0 : mode = convert_mode(&msgtyp, msgflg);
1112 :
1113 0 : rcu_read_lock();
1114 0 : msq = msq_obtain_object_check(ns, msqid);
1115 0 : if (IS_ERR(msq)) {
1116 0 : rcu_read_unlock();
1117 0 : free_copy(copy);
1118 0 : return PTR_ERR(msq);
1119 : }
1120 :
1121 0 : for (;;) {
1122 0 : struct msg_receiver msr_d;
1123 :
1124 0 : msg = ERR_PTR(-EACCES);
1125 0 : if (ipcperms(ns, &msq->q_perm, S_IRUGO))
1126 0 : goto out_unlock1;
1127 :
1128 0 : ipc_lock_object(&msq->q_perm);
1129 :
1130 : /* raced with RMID? */
1131 0 : if (!ipc_valid_object(&msq->q_perm)) {
1132 0 : msg = ERR_PTR(-EIDRM);
1133 0 : goto out_unlock0;
1134 : }
1135 :
1136 0 : msg = find_msg(msq, &msgtyp, mode);
1137 0 : if (!IS_ERR(msg)) {
1138 : /*
1139 : * Found a suitable message.
1140 : * Unlink it from the queue.
1141 : */
1142 0 : if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
1143 0 : msg = ERR_PTR(-E2BIG);
1144 0 : goto out_unlock0;
1145 : }
1146 : /*
1147 : * If we are copying, then do not unlink message and do
1148 : * not update queue parameters.
1149 : */
1150 0 : if (msgflg & MSG_COPY) {
1151 : msg = copy_msg(msg, copy);
1152 : goto out_unlock0;
1153 : }
1154 :
1155 0 : list_del(&msg->m_list);
1156 0 : msq->q_qnum--;
1157 0 : msq->q_rtime = ktime_get_real_seconds();
1158 0 : ipc_update_pid(&msq->q_lrpid, task_tgid(current));
1159 0 : msq->q_cbytes -= msg->m_ts;
1160 0 : atomic_sub(msg->m_ts, &ns->msg_bytes);
1161 0 : atomic_dec(&ns->msg_hdrs);
1162 0 : ss_wakeup(msq, &wake_q, false);
1163 :
1164 0 : goto out_unlock0;
1165 : }
1166 :
1167 : /* No message waiting. Wait for a message */
1168 0 : if (msgflg & IPC_NOWAIT) {
1169 0 : msg = ERR_PTR(-ENOMSG);
1170 0 : goto out_unlock0;
1171 : }
1172 :
1173 0 : list_add_tail(&msr_d.r_list, &msq->q_receivers);
1174 0 : msr_d.r_tsk = current;
1175 0 : msr_d.r_msgtype = msgtyp;
1176 0 : msr_d.r_mode = mode;
1177 0 : if (msgflg & MSG_NOERROR)
1178 0 : msr_d.r_maxsize = INT_MAX;
1179 : else
1180 0 : msr_d.r_maxsize = bufsz;
1181 :
1182 : /* memory barrier not require due to ipc_lock_object() */
1183 0 : WRITE_ONCE(msr_d.r_msg, ERR_PTR(-EAGAIN));
1184 :
1185 : /* memory barrier not required, we own ipc_lock_object() */
1186 0 : __set_current_state(TASK_INTERRUPTIBLE);
1187 :
1188 0 : ipc_unlock_object(&msq->q_perm);
1189 0 : rcu_read_unlock();
1190 0 : 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 0 : 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 0 : msg = READ_ONCE(msr_d.r_msg);
1214 0 : if (msg != ERR_PTR(-EAGAIN)) {
1215 : /* see MSG_BARRIER for purpose/pairing */
1216 0 : smp_acquire__after_ctrl_dep();
1217 :
1218 0 : goto out_unlock1;
1219 : }
1220 :
1221 : /*
1222 : * ... or see -EAGAIN, acquire the lock to check the message
1223 : * again.
1224 : */
1225 0 : ipc_lock_object(&msq->q_perm);
1226 :
1227 0 : msg = READ_ONCE(msr_d.r_msg);
1228 0 : if (msg != ERR_PTR(-EAGAIN))
1229 0 : goto out_unlock0;
1230 :
1231 0 : list_del(&msr_d.r_list);
1232 0 : if (signal_pending(current)) {
1233 0 : msg = ERR_PTR(-ERESTARTNOHAND);
1234 0 : goto out_unlock0;
1235 : }
1236 :
1237 0 : ipc_unlock_object(&msq->q_perm);
1238 : }
1239 :
1240 0 : out_unlock0:
1241 0 : ipc_unlock_object(&msq->q_perm);
1242 0 : wake_up_q(&wake_q);
1243 0 : out_unlock1:
1244 0 : rcu_read_unlock();
1245 0 : if (IS_ERR(msg)) {
1246 0 : free_copy(copy);
1247 0 : return PTR_ERR(msg);
1248 : }
1249 :
1250 0 : bufsz = msg_handler(buf, msg, bufsz);
1251 0 : free_msg(msg);
1252 :
1253 0 : return bufsz;
1254 : }
1255 :
1256 0 : long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
1257 : long msgtyp, int msgflg)
1258 : {
1259 0 : return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
1260 : }
1261 :
1262 0 : SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
1263 : long, msgtyp, int, msgflg)
1264 : {
1265 0 : return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1266 : }
1267 :
1268 : #ifdef CONFIG_COMPAT
1269 0 : static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
1270 : {
1271 0 : struct compat_msgbuf __user *msgp = dest;
1272 0 : size_t msgsz;
1273 :
1274 0 : if (put_user(msg->m_type, &msgp->mtype))
1275 : return -EFAULT;
1276 :
1277 0 : msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
1278 0 : if (store_msg(msgp->mtext, msg, msgsz))
1279 : return -EFAULT;
1280 0 : return msgsz;
1281 : }
1282 :
1283 0 : long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
1284 : compat_long_t msgtyp, int msgflg)
1285 : {
1286 0 : return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp,
1287 : msgflg, compat_do_msg_fill);
1288 : }
1289 :
1290 0 : COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
1291 : compat_ssize_t, msgsz, compat_long_t, msgtyp,
1292 : int, msgflg)
1293 : {
1294 0 : return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1295 : }
1296 : #endif
1297 :
1298 1 : void msg_init_ns(struct ipc_namespace *ns)
1299 : {
1300 1 : ns->msg_ctlmax = MSGMAX;
1301 1 : ns->msg_ctlmnb = MSGMNB;
1302 1 : ns->msg_ctlmni = MSGMNI;
1303 :
1304 1 : atomic_set(&ns->msg_bytes, 0);
1305 1 : atomic_set(&ns->msg_hdrs, 0);
1306 1 : ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
1307 1 : }
1308 :
1309 : #ifdef CONFIG_IPC_NS
1310 : void 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
1319 0 : static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
1320 : {
1321 0 : struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1322 0 : struct user_namespace *user_ns = seq_user_ns(s);
1323 0 : struct kern_ipc_perm *ipcp = it;
1324 0 : struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
1325 :
1326 0 : 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 0 : 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 0 : return 0;
1344 : }
1345 : #endif
1346 :
1347 1 : void __init msg_init(void)
1348 : {
1349 1 : msg_init_ns(&init_ipc_ns);
1350 :
1351 1 : ipc_init_proc_interface("sysvipc/msg",
1352 : " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
1353 : IPC_MSG_IDS, sysvipc_msg_proc_show);
1354 1 : }
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