1 // SPDX-License-Identifier: GPL-2.0
4 * Copyright (C) 1992 Krishna Balasubramanian
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
12 * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
14 * mostly rewritten, threaded and wake-one semantics added
15 * MSGMAX limit removed, sysctl's added
16 * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
18 * support for audit of ipc object properties and permission changes
19 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
23 * Pavel Emelianov <xemul@openvz.org>
26 #include <linux/capability.h>
27 #include <linux/msg.h>
28 #include <linux/spinlock.h>
29 #include <linux/init.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>
43 #include <asm/current.h>
44 #include <linux/uaccess.h>
47 /* one msq_queue structure for each present queue on the system */
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 */
59 struct list_head q_messages
;
60 struct list_head q_receivers
;
61 struct list_head q_senders
;
65 * MSG_BARRIER Locking:
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
74 /* one msg_receiver structure for each sleeping receiver */
76 struct list_head r_list
;
77 struct task_struct
*r_tsk
;
83 struct msg_msg
*r_msg
;
86 /* one msg_sender for each sleeping sender */
88 struct list_head list
;
89 struct task_struct
*tsk
;
94 #define SEARCH_EQUAL 2
95 #define SEARCH_NOTEQUAL 3
96 #define SEARCH_LESSEQUAL 4
97 #define SEARCH_NUMBER 5
99 #define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
101 static inline struct msg_queue
*msq_obtain_object(struct ipc_namespace
*ns
, int id
)
103 struct kern_ipc_perm
*ipcp
= ipc_obtain_object_idr(&msg_ids(ns
), id
);
106 return ERR_CAST(ipcp
);
108 return container_of(ipcp
, struct msg_queue
, q_perm
);
111 static inline struct msg_queue
*msq_obtain_object_check(struct ipc_namespace
*ns
,
114 struct kern_ipc_perm
*ipcp
= ipc_obtain_object_check(&msg_ids(ns
), id
);
117 return ERR_CAST(ipcp
);
119 return container_of(ipcp
, struct msg_queue
, q_perm
);
122 static inline void msg_rmid(struct ipc_namespace
*ns
, struct msg_queue
*s
)
124 ipc_rmid(&msg_ids(ns
), &s
->q_perm
);
127 static void msg_rcu_free(struct rcu_head
*head
)
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
);
132 security_msg_queue_free(&msq
->q_perm
);
137 * newque - Create a new msg queue
139 * @params: ptr to the structure that contains the key and msgflg
141 * Called with msg_ids.rwsem held (writer)
143 static int newque(struct ipc_namespace
*ns
, struct ipc_params
*params
)
145 struct msg_queue
*msq
;
147 key_t key
= params
->key
;
148 int msgflg
= params
->flg
;
150 msq
= kvmalloc(sizeof(*msq
), GFP_KERNEL
);
154 msq
->q_perm
.mode
= msgflg
& S_IRWXUGO
;
155 msq
->q_perm
.key
= key
;
157 msq
->q_perm
.security
= NULL
;
158 retval
= security_msg_queue_alloc(&msq
->q_perm
);
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
);
173 /* ipc_addid() locks msq upon success. */
174 retval
= ipc_addid(&msg_ids(ns
), &msq
->q_perm
, ns
->msg_ctlmni
);
176 ipc_rcu_putref(&msq
->q_perm
, msg_rcu_free
);
180 ipc_unlock_object(&msq
->q_perm
);
183 return msq
->q_perm
.id
;
186 static inline bool msg_fits_inqueue(struct msg_queue
*msq
, size_t msgsz
)
188 return msgsz
+ msq
->q_cbytes
<= msq
->q_qbytes
&&
189 1 + msq
->q_qnum
<= msq
->q_qbytes
;
192 static inline void ss_add(struct msg_queue
*msq
,
193 struct msg_sender
*mss
, size_t msgsz
)
198 * No memory barrier required: we did ipc_lock_object(),
199 * and the waker obtains that lock before calling wake_q_add().
201 __set_current_state(TASK_INTERRUPTIBLE
);
202 list_add_tail(&mss
->list
, &msq
->q_senders
);
205 static inline void ss_del(struct msg_sender
*mss
)
208 list_del(&mss
->list
);
211 static void ss_wakeup(struct msg_queue
*msq
,
212 struct wake_q_head
*wake_q
, bool kill
)
214 struct msg_sender
*mss
, *t
;
215 struct task_struct
*stop_tsk
= NULL
;
216 struct list_head
*h
= &msq
->q_senders
;
218 list_for_each_entry_safe(mss
, t
, h
, list
) {
220 mss
->list
.next
= NULL
;
223 * Stop at the first task we don't wakeup,
224 * we've already iterated the original
227 else if (stop_tsk
== mss
->tsk
)
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
236 else if (!msg_fits_inqueue(msq
, mss
->msgsz
)) {
240 list_move_tail(&mss
->list
, &msq
->q_senders
);
244 wake_q_add(wake_q
, mss
->tsk
);
248 static void expunge_all(struct msg_queue
*msq
, int res
,
249 struct wake_q_head
*wake_q
)
251 struct msg_receiver
*msr
, *t
;
253 list_for_each_entry_safe(msr
, t
, &msq
->q_receivers
, r_list
) {
254 struct task_struct
*r_tsk
;
256 r_tsk
= get_task_struct(msr
->r_tsk
);
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
);
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.
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.
272 static void freeque(struct ipc_namespace
*ns
, struct kern_ipc_perm
*ipcp
)
274 __releases(&msq
->q_perm
)
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
);
280 expunge_all(msq
, -EIDRM
, &wake_q
);
281 ss_wakeup(msq
, &wake_q
, true);
283 ipc_unlock_object(&msq
->q_perm
);
287 list_for_each_entry_safe(msg
, t
, &msq
->q_messages
, m_list
) {
288 atomic_dec(&ns
->msg_hdrs
);
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
);
297 long ksys_msgget(key_t key
, int msgflg
)
299 struct ipc_namespace
*ns
;
300 static const struct ipc_ops msg_ops
= {
302 .associate
= security_msg_queue_associate
,
304 struct ipc_params msg_params
;
306 ns
= current
->nsproxy
->ipc_ns
;
308 msg_params
.key
= key
;
309 msg_params
.flg
= msgflg
;
311 return ipcget(ns
, &msg_ids(ns
), &msg_ops
, &msg_params
);
314 SYSCALL_DEFINE2(msgget
, key_t
, key
, int, msgflg
)
316 return ksys_msgget(key
, msgflg
);
319 static inline unsigned long
320 copy_msqid_to_user(void __user
*buf
, struct msqid64_ds
*in
, int version
)
324 return copy_to_user(buf
, in
, sizeof(*in
));
329 memset(&out
, 0, sizeof(out
));
331 ipc64_perm_to_ipc_perm(&in
->msg_perm
, &out
.msg_perm
);
333 out
.msg_stime
= in
->msg_stime
;
334 out
.msg_rtime
= in
->msg_rtime
;
335 out
.msg_ctime
= in
->msg_ctime
;
337 if (in
->msg_cbytes
> USHRT_MAX
)
338 out
.msg_cbytes
= USHRT_MAX
;
340 out
.msg_cbytes
= in
->msg_cbytes
;
341 out
.msg_lcbytes
= in
->msg_cbytes
;
343 if (in
->msg_qnum
> USHRT_MAX
)
344 out
.msg_qnum
= USHRT_MAX
;
346 out
.msg_qnum
= in
->msg_qnum
;
348 if (in
->msg_qbytes
> USHRT_MAX
)
349 out
.msg_qbytes
= USHRT_MAX
;
351 out
.msg_qbytes
= in
->msg_qbytes
;
352 out
.msg_lqbytes
= in
->msg_qbytes
;
354 out
.msg_lspid
= in
->msg_lspid
;
355 out
.msg_lrpid
= in
->msg_lrpid
;
357 return copy_to_user(buf
, &out
, sizeof(out
));
364 static inline unsigned long
365 copy_msqid_from_user(struct msqid64_ds
*out
, void __user
*buf
, int version
)
369 if (copy_from_user(out
, buf
, sizeof(*out
)))
374 struct msqid_ds tbuf_old
;
376 if (copy_from_user(&tbuf_old
, buf
, sizeof(tbuf_old
)))
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
;
383 if (tbuf_old
.msg_qbytes
== 0)
384 out
->msg_qbytes
= tbuf_old
.msg_lqbytes
;
386 out
->msg_qbytes
= tbuf_old
.msg_qbytes
;
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.
400 static int msgctl_down(struct ipc_namespace
*ns
, int msqid
, int cmd
,
401 struct ipc64_perm
*perm
, int msg_qbytes
)
403 struct kern_ipc_perm
*ipcp
;
404 struct msg_queue
*msq
;
407 down_write(&msg_ids(ns
).rwsem
);
410 ipcp
= ipcctl_obtain_check(ns
, &msg_ids(ns
), msqid
, cmd
,
417 msq
= container_of(ipcp
, struct msg_queue
, q_perm
);
419 err
= security_msg_queue_msgctl(&msq
->q_perm
, cmd
);
425 ipc_lock_object(&msq
->q_perm
);
426 /* freeque unlocks the ipc object and rcu */
431 DEFINE_WAKE_Q(wake_q
);
433 if (msg_qbytes
> ns
->msg_ctlmnb
&&
434 !capable(CAP_SYS_RESOURCE
)) {
439 ipc_lock_object(&msq
->q_perm
);
440 err
= ipc_update_perm(perm
, ipcp
);
444 msq
->q_qbytes
= msg_qbytes
;
446 msq
->q_ctime
= ktime_get_real_seconds();
448 * Sleeping receivers might be excluded by
449 * stricter permissions.
451 expunge_all(msq
, -EAGAIN
, &wake_q
);
453 * Sleeping senders might be able to send
454 * due to a larger queue size.
456 ss_wakeup(msq
, &wake_q
, false);
457 ipc_unlock_object(&msq
->q_perm
);
468 ipc_unlock_object(&msq
->q_perm
);
472 up_write(&msg_ids(ns
).rwsem
);
476 static int msgctl_info(struct ipc_namespace
*ns
, int msqid
,
477 int cmd
, struct msginfo
*msginfo
)
483 * We must not return kernel stack data.
484 * due to padding, it's not enough
485 * to set all member fields.
487 err
= security_msg_queue_msgctl(NULL
, cmd
);
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
);
503 msginfo
->msgmap
= MSGMAP
;
504 msginfo
->msgpool
= MSGPOOL
;
505 msginfo
->msgtql
= MSGTQL
;
507 max_idx
= ipc_get_maxidx(&msg_ids(ns
));
508 up_read(&msg_ids(ns
).rwsem
);
509 return (max_idx
< 0) ? 0 : max_idx
;
512 static int msgctl_stat(struct ipc_namespace
*ns
, int msqid
,
513 int cmd
, struct msqid64_ds
*p
)
515 struct msg_queue
*msq
;
518 memset(p
, 0, sizeof(*p
));
521 if (cmd
== MSG_STAT
|| cmd
== MSG_STAT_ANY
) {
522 msq
= msq_obtain_object(ns
, msqid
);
527 } else { /* IPC_STAT */
528 msq
= msq_obtain_object_check(ns
, msqid
);
535 /* see comment for SHM_STAT_ANY */
536 if (cmd
== MSG_STAT_ANY
)
537 audit_ipc_obj(&msq
->q_perm
);
540 if (ipcperms(ns
, &msq
->q_perm
, S_IRUGO
))
544 err
= security_msg_queue_msgctl(&msq
->q_perm
, cmd
);
548 ipc_lock_object(&msq
->q_perm
);
550 if (!ipc_valid_object(&msq
->q_perm
)) {
551 ipc_unlock_object(&msq
->q_perm
);
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
;
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;
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
);
571 if (cmd
== IPC_STAT
) {
574 * Return 0 on success
579 * MSG_STAT and MSG_STAT_ANY (both Linux specific)
580 * Return the full id, including the sequence number
582 err
= msq
->q_perm
.id
;
585 ipc_unlock_object(&msq
->q_perm
);
591 static long ksys_msgctl(int msqid
, int cmd
, struct msqid_ds __user
*buf
, int version
)
593 struct ipc_namespace
*ns
;
594 struct msqid64_ds msqid64
;
597 if (msqid
< 0 || cmd
< 0)
600 ns
= current
->nsproxy
->ipc_ns
;
605 struct msginfo msginfo
;
606 err
= msgctl_info(ns
, msqid
, cmd
, &msginfo
);
609 if (copy_to_user(buf
, &msginfo
, sizeof(struct msginfo
)))
613 case MSG_STAT
: /* msqid is an index rather than a msg queue id */
616 err
= msgctl_stat(ns
, msqid
, cmd
, &msqid64
);
619 if (copy_msqid_to_user(buf
, &msqid64
, version
))
623 if (copy_msqid_from_user(&msqid64
, buf
, version
))
625 return msgctl_down(ns
, msqid
, cmd
, &msqid64
.msg_perm
,
628 return msgctl_down(ns
, msqid
, cmd
, NULL
, 0);
634 SYSCALL_DEFINE3(msgctl
, int, msqid
, int, cmd
, struct msqid_ds __user
*, buf
)
636 return ksys_msgctl(msqid
, cmd
, buf
, IPC_64
);
639 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
640 long ksys_old_msgctl(int msqid
, int cmd
, struct msqid_ds __user
*buf
)
642 int version
= ipc_parse_version(&cmd
);
644 return ksys_msgctl(msqid
, cmd
, buf
, version
);
647 SYSCALL_DEFINE3(old_msgctl
, int, msqid
, int, cmd
, struct msqid_ds __user
*, buf
)
649 return ksys_old_msgctl(msqid
, cmd
, buf
);
655 struct 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
;
671 static int copy_compat_msqid_from_user(struct msqid64_ds
*out
, void __user
*buf
,
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
))
679 if (get_user(out
->msg_qbytes
, &p
->msg_qbytes
))
682 struct compat_msqid_ds __user
*p
= buf
;
683 if (get_compat_ipc_perm(&out
->msg_perm
, &p
->msg_perm
))
685 if (get_user(out
->msg_qbytes
, &p
->msg_qbytes
))
691 static int copy_compat_msqid_to_user(void __user
*buf
, struct msqid64_ds
*in
,
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
));
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
));
726 static long compat_ksys_msgctl(int msqid
, int cmd
, void __user
*uptr
, int version
)
728 struct ipc_namespace
*ns
;
730 struct msqid64_ds msqid64
;
732 ns
= current
->nsproxy
->ipc_ns
;
734 if (msqid
< 0 || cmd
< 0)
737 switch (cmd
& (~IPC_64
)) {
740 struct msginfo msginfo
;
741 err
= msgctl_info(ns
, msqid
, cmd
, &msginfo
);
744 if (copy_to_user(uptr
, &msginfo
, sizeof(struct msginfo
)))
751 err
= msgctl_stat(ns
, msqid
, cmd
, &msqid64
);
754 if (copy_compat_msqid_to_user(uptr
, &msqid64
, version
))
758 if (copy_compat_msqid_from_user(&msqid64
, uptr
, version
))
760 return msgctl_down(ns
, msqid
, cmd
, &msqid64
.msg_perm
, msqid64
.msg_qbytes
);
762 return msgctl_down(ns
, msqid
, cmd
, NULL
, 0);
768 COMPAT_SYSCALL_DEFINE3(msgctl
, int, msqid
, int, cmd
, void __user
*, uptr
)
770 return compat_ksys_msgctl(msqid
, cmd
, uptr
, IPC_64
);
773 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
774 long compat_ksys_old_msgctl(int msqid
, int cmd
, void __user
*uptr
)
776 int version
= compat_ipc_parse_version(&cmd
);
778 return compat_ksys_msgctl(msqid
, cmd
, uptr
, version
);
781 COMPAT_SYSCALL_DEFINE3(old_msgctl
, int, msqid
, int, cmd
, void __user
*, uptr
)
783 return compat_ksys_old_msgctl(msqid
, cmd
, uptr
);
788 static int testmsg(struct msg_msg
*msg
, long type
, int mode
)
794 case SEARCH_LESSEQUAL
:
795 if (msg
->m_type
<= type
)
799 if (msg
->m_type
== type
)
802 case SEARCH_NOTEQUAL
:
803 if (msg
->m_type
!= type
)
810 static inline int pipelined_send(struct msg_queue
*msq
, struct msg_msg
*msg
,
811 struct wake_q_head
*wake_q
)
813 struct msg_receiver
*msr
, *t
;
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
)) {
820 list_del(&msr
->r_list
);
821 if (msr
->r_maxsize
< msg
->m_ts
) {
822 wake_q_add(wake_q
, msr
->r_tsk
);
824 /* See expunge_all regarding memory barrier */
825 smp_store_release(&msr
->r_msg
, ERR_PTR(-E2BIG
));
827 ipc_update_pid(&msq
->q_lrpid
, task_pid(msr
->r_tsk
));
828 msq
->q_rtime
= ktime_get_real_seconds();
830 wake_q_add(wake_q
, msr
->r_tsk
);
832 /* See expunge_all regarding memory barrier */
833 smp_store_release(&msr
->r_msg
, msg
);
842 static long do_msgsnd(int msqid
, long mtype
, void __user
*mtext
,
843 size_t msgsz
, int msgflg
)
845 struct msg_queue
*msq
;
848 struct ipc_namespace
*ns
;
849 DEFINE_WAKE_Q(wake_q
);
851 ns
= current
->nsproxy
->ipc_ns
;
853 if (msgsz
> ns
->msg_ctlmax
|| (long) msgsz
< 0 || msqid
< 0)
858 msg
= load_msg(mtext
, msgsz
);
866 msq
= msq_obtain_object_check(ns
, msqid
);
872 ipc_lock_object(&msq
->q_perm
);
878 if (ipcperms(ns
, &msq
->q_perm
, S_IWUGO
))
881 /* raced with RMID? */
882 if (!ipc_valid_object(&msq
->q_perm
)) {
887 err
= security_msg_queue_msgsnd(&msq
->q_perm
, msg
, msgflg
);
891 if (msg_fits_inqueue(msq
, msgsz
))
894 /* queue full, wait: */
895 if (msgflg
& IPC_NOWAIT
) {
900 /* enqueue the sender and prepare to block */
901 ss_add(msq
, &s
, msgsz
);
903 if (!ipc_rcu_getref(&msq
->q_perm
)) {
908 ipc_unlock_object(&msq
->q_perm
);
913 ipc_lock_object(&msq
->q_perm
);
915 ipc_rcu_putref(&msq
->q_perm
, msg_rcu_free
);
916 /* raced with RMID? */
917 if (!ipc_valid_object(&msq
->q_perm
)) {
923 if (signal_pending(current
)) {
924 err
= -ERESTARTNOHAND
;
930 ipc_update_pid(&msq
->q_lspid
, task_tgid(current
));
931 msq
->q_stime
= ktime_get_real_seconds();
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
;
938 atomic_add(msgsz
, &ns
->msg_bytes
);
939 atomic_inc(&ns
->msg_hdrs
);
946 ipc_unlock_object(&msq
->q_perm
);
955 long ksys_msgsnd(int msqid
, struct msgbuf __user
*msgp
, size_t msgsz
,
960 if (get_user(mtype
, &msgp
->mtype
))
962 return do_msgsnd(msqid
, mtype
, msgp
->mtext
, msgsz
, msgflg
);
965 SYSCALL_DEFINE4(msgsnd
, int, msqid
, struct msgbuf __user
*, msgp
, size_t, msgsz
,
968 return ksys_msgsnd(msqid
, msgp
, msgsz
, msgflg
);
973 struct compat_msgbuf
{
978 long compat_ksys_msgsnd(int msqid
, compat_uptr_t msgp
,
979 compat_ssize_t msgsz
, int msgflg
)
981 struct compat_msgbuf __user
*up
= compat_ptr(msgp
);
984 if (get_user(mtype
, &up
->mtype
))
986 return do_msgsnd(msqid
, mtype
, up
->mtext
, (ssize_t
)msgsz
, msgflg
);
989 COMPAT_SYSCALL_DEFINE4(msgsnd
, int, msqid
, compat_uptr_t
, msgp
,
990 compat_ssize_t
, msgsz
, int, msgflg
)
992 return compat_ksys_msgsnd(msqid
, msgp
, msgsz
, msgflg
);
996 static inline int convert_mode(long *msgtyp
, int msgflg
)
998 if (msgflg
& MSG_COPY
)
999 return SEARCH_NUMBER
;
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).
1009 if (*msgtyp
== LONG_MIN
) /* -LONG_MIN is undefined */
1013 return SEARCH_LESSEQUAL
;
1015 if (msgflg
& MSG_EXCEPT
)
1016 return SEARCH_NOTEQUAL
;
1017 return SEARCH_EQUAL
;
1020 static long do_msg_fill(void __user
*dest
, struct msg_msg
*msg
, size_t bufsz
)
1022 struct msgbuf __user
*msgp
= dest
;
1025 if (put_user(msg
->m_type
, &msgp
->mtype
))
1028 msgsz
= (bufsz
> msg
->m_ts
) ? msg
->m_ts
: bufsz
;
1029 if (store_msg(msgp
->mtext
, msg
, msgsz
))
1034 #ifdef CONFIG_CHECKPOINT_RESTORE
1036 * This function creates new kernel message structure, large enough to store
1037 * bufsz message bytes.
1039 static inline struct msg_msg
*prepare_copy(void __user
*buf
, size_t bufsz
)
1041 struct msg_msg
*copy
;
1044 * Create dummy message to copy real message to.
1046 copy
= load_msg(buf
, bufsz
);
1052 static inline void free_copy(struct msg_msg
*copy
)
1058 static inline struct msg_msg
*prepare_copy(void __user
*buf
, size_t bufsz
)
1060 return ERR_PTR(-ENOSYS
);
1063 static inline void free_copy(struct msg_msg
*copy
)
1068 static struct msg_msg
*find_msg(struct msg_queue
*msq
, long *msgtyp
, int mode
)
1070 struct msg_msg
*msg
, *found
= NULL
;
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
,
1077 if (mode
== SEARCH_LESSEQUAL
&& msg
->m_type
!= 1) {
1078 *msgtyp
= msg
->m_type
- 1;
1080 } else if (mode
== SEARCH_NUMBER
) {
1081 if (*msgtyp
== count
)
1089 return found
?: ERR_PTR(-EAGAIN
);
1092 static 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))
1096 struct msg_queue
*msq
;
1097 struct ipc_namespace
*ns
;
1098 struct msg_msg
*msg
, *copy
= NULL
;
1099 DEFINE_WAKE_Q(wake_q
);
1101 ns
= current
->nsproxy
->ipc_ns
;
1103 if (msqid
< 0 || (long) bufsz
< 0)
1106 if (msgflg
& MSG_COPY
) {
1107 if ((msgflg
& MSG_EXCEPT
) || !(msgflg
& IPC_NOWAIT
))
1109 copy
= prepare_copy(buf
, min_t(size_t, bufsz
, ns
->msg_ctlmax
));
1111 return PTR_ERR(copy
);
1113 mode
= convert_mode(&msgtyp
, msgflg
);
1116 msq
= msq_obtain_object_check(ns
, msqid
);
1120 return PTR_ERR(msq
);
1124 struct msg_receiver msr_d
;
1126 msg
= ERR_PTR(-EACCES
);
1127 if (ipcperms(ns
, &msq
->q_perm
, S_IRUGO
))
1130 ipc_lock_object(&msq
->q_perm
);
1132 /* raced with RMID? */
1133 if (!ipc_valid_object(&msq
->q_perm
)) {
1134 msg
= ERR_PTR(-EIDRM
);
1138 msg
= find_msg(msq
, &msgtyp
, mode
);
1141 * Found a suitable message.
1142 * Unlink it from the queue.
1144 if ((bufsz
< msg
->m_ts
) && !(msgflg
& MSG_NOERROR
)) {
1145 msg
= ERR_PTR(-E2BIG
);
1149 * If we are copying, then do not unlink message and do
1150 * not update queue parameters.
1152 if (msgflg
& MSG_COPY
) {
1153 msg
= copy_msg(msg
, copy
);
1157 list_del(&msg
->m_list
);
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);
1169 /* No message waiting. Wait for a message */
1170 if (msgflg
& IPC_NOWAIT
) {
1171 msg
= ERR_PTR(-ENOMSG
);
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
;
1182 msr_d
.r_maxsize
= bufsz
;
1184 /* memory barrier not require due to ipc_lock_object() */
1185 WRITE_ONCE(msr_d
.r_msg
, ERR_PTR(-EAGAIN
));
1187 /* memory barrier not required, we own ipc_lock_object() */
1188 __set_current_state(TASK_INTERRUPTIBLE
);
1190 ipc_unlock_object(&msq
->q_perm
);
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
1200 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
1201 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
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.
1212 * Should the process wake up before this wakeup (due to a
1213 * signal) it will either see the message and continue ...
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();
1224 * ... or see -EAGAIN, acquire the lock to check the message
1227 ipc_lock_object(&msq
->q_perm
);
1229 msg
= READ_ONCE(msr_d
.r_msg
);
1230 if (msg
!= ERR_PTR(-EAGAIN
))
1233 list_del(&msr_d
.r_list
);
1234 if (signal_pending(current
)) {
1235 msg
= ERR_PTR(-ERESTARTNOHAND
);
1239 ipc_unlock_object(&msq
->q_perm
);
1243 ipc_unlock_object(&msq
->q_perm
);
1249 return PTR_ERR(msg
);
1252 bufsz
= msg_handler(buf
, msg
, bufsz
);
1258 long ksys_msgrcv(int msqid
, struct msgbuf __user
*msgp
, size_t msgsz
,
1259 long msgtyp
, int msgflg
)
1261 return do_msgrcv(msqid
, msgp
, msgsz
, msgtyp
, msgflg
, do_msg_fill
);
1264 SYSCALL_DEFINE5(msgrcv
, int, msqid
, struct msgbuf __user
*, msgp
, size_t, msgsz
,
1265 long, msgtyp
, int, msgflg
)
1267 return ksys_msgrcv(msqid
, msgp
, msgsz
, msgtyp
, msgflg
);
1270 #ifdef CONFIG_COMPAT
1271 static long compat_do_msg_fill(void __user
*dest
, struct msg_msg
*msg
, size_t bufsz
)
1273 struct compat_msgbuf __user
*msgp
= dest
;
1276 if (put_user(msg
->m_type
, &msgp
->mtype
))
1279 msgsz
= (bufsz
> msg
->m_ts
) ? msg
->m_ts
: bufsz
;
1280 if (store_msg(msgp
->mtext
, msg
, msgsz
))
1285 long compat_ksys_msgrcv(int msqid
, compat_uptr_t msgp
, compat_ssize_t msgsz
,
1286 compat_long_t msgtyp
, int msgflg
)
1288 return do_msgrcv(msqid
, compat_ptr(msgp
), (ssize_t
)msgsz
, (long)msgtyp
,
1289 msgflg
, compat_do_msg_fill
);
1292 COMPAT_SYSCALL_DEFINE5(msgrcv
, int, msqid
, compat_uptr_t
, msgp
,
1293 compat_ssize_t
, msgsz
, compat_long_t
, msgtyp
,
1296 return compat_ksys_msgrcv(msqid
, msgp
, msgsz
, msgtyp
, msgflg
);
1300 void msg_init_ns(struct ipc_namespace
*ns
)
1302 ns
->msg_ctlmax
= MSGMAX
;
1303 ns
->msg_ctlmnb
= MSGMNB
;
1304 ns
->msg_ctlmni
= MSGMNI
;
1306 atomic_set(&ns
->msg_bytes
, 0);
1307 atomic_set(&ns
->msg_hdrs
, 0);
1308 ipc_init_ids(&ns
->ids
[IPC_MSG_IDS
]);
1311 #ifdef CONFIG_IPC_NS
1312 void msg_exit_ns(struct ipc_namespace
*ns
)
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
);
1320 #ifdef CONFIG_PROC_FS
1321 static int sysvipc_msg_proc_show(struct seq_file
*s
, void *it
)
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
);
1329 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n",
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
),
1349 void __init
msg_init(void)
1351 msg_init_ns(&init_ipc_ns
);
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
);