3 * Copyright (C) 1992 Krishna Balasubramanian
5 * Removed all the remaining kerneld mess
6 * Catch the -EFAULT stuff properly
7 * Use GFP_KERNEL for messages as in 1.2
8 * Fixed up the unchecked user space derefs
9 * Copyright (C) 1998 Alan Cox & Andi Kleen
11 * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
13 * mostly rewritten, threaded and wake-one semantics added
14 * MSGMAX limit removed, sysctl's added
15 * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
17 * support for audit of ipc object properties and permission changes
18 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
22 * Pavel Emelianov <xemul@openvz.org>
25 #include <linux/capability.h>
26 #include <linux/slab.h>
27 #include <linux/msg.h>
28 #include <linux/spinlock.h>
29 #include <linux/init.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>
41 #include <asm/current.h>
42 #include <asm/uaccess.h>
46 * one msg_receiver structure for each sleeping receiver:
49 struct list_head r_list;
50 struct task_struct *r_tsk;
56 struct msg_msg *volatile r_msg;
59 /* one msg_sender for each sleeping sender */
61 struct list_head list;
62 struct task_struct *tsk;
66 #define SEARCH_EQUAL 2
67 #define SEARCH_NOTEQUAL 3
68 #define SEARCH_LESSEQUAL 4
70 #define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
72 #define msg_unlock(msq) ipc_unlock(&(msq)->q_perm)
74 static void freeque(struct ipc_namespace *, struct kern_ipc_perm *);
75 static int newque(struct ipc_namespace *, struct ipc_params *);
77 static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
80 void msg_init_ns(struct ipc_namespace *ns)
82 ns->msg_ctlmax = MSGMAX;
83 ns->msg_ctlmnb = MSGMNB;
84 ns->msg_ctlmni = MSGMNI;
85 atomic_set(&ns->msg_bytes, 0);
86 atomic_set(&ns->msg_hdrs, 0);
87 ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
91 void msg_exit_ns(struct ipc_namespace *ns)
93 free_ipcs(ns, &msg_ids(ns), freeque);
97 void __init msg_init(void)
99 msg_init_ns(&init_ipc_ns);
100 ipc_init_proc_interface("sysvipc/msg",
101 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
102 IPC_MSG_IDS, sysvipc_msg_proc_show);
106 * This routine is called in the paths where the rw_mutex is held to protect
107 * access to the idr tree.
109 static inline struct msg_queue *msg_lock_check_down(struct ipc_namespace *ns,
112 struct kern_ipc_perm *ipcp = ipc_lock_check_down(&msg_ids(ns), id);
115 return (struct msg_queue *)ipcp;
117 return container_of(ipcp, struct msg_queue, q_perm);
121 * msg_lock_(check_) routines are called in the paths where the rw_mutex
124 static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id)
126 struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id);
129 return (struct msg_queue *)ipcp;
131 return container_of(ipcp, struct msg_queue, q_perm);
134 static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns,
137 struct kern_ipc_perm *ipcp = ipc_lock_check(&msg_ids(ns), id);
140 return (struct msg_queue *)ipcp;
142 return container_of(ipcp, struct msg_queue, q_perm);
145 static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
147 ipc_rmid(&msg_ids(ns), &s->q_perm);
151 * newque - Create a new msg queue
153 * @params: ptr to the structure that contains the key and msgflg
155 * Called with msg_ids.rw_mutex held (writer)
157 static int newque(struct ipc_namespace *ns, struct ipc_params *params)
159 struct msg_queue *msq;
161 key_t key = params->key;
162 int msgflg = params->flg;
164 msq = ipc_rcu_alloc(sizeof(*msq));
168 msq->q_perm.mode = msgflg & S_IRWXUGO;
169 msq->q_perm.key = key;
171 msq->q_perm.security = NULL;
172 retval = security_msg_queue_alloc(msq);
179 * ipc_addid() locks msq
181 id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
183 security_msg_queue_free(msq);
188 msq->q_stime = msq->q_rtime = 0;
189 msq->q_ctime = get_seconds();
190 msq->q_cbytes = msq->q_qnum = 0;
191 msq->q_qbytes = ns->msg_ctlmnb;
192 msq->q_lspid = msq->q_lrpid = 0;
193 INIT_LIST_HEAD(&msq->q_messages);
194 INIT_LIST_HEAD(&msq->q_receivers);
195 INIT_LIST_HEAD(&msq->q_senders);
199 return msq->q_perm.id;
202 static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss)
205 current->state = TASK_INTERRUPTIBLE;
206 list_add_tail(&mss->list, &msq->q_senders);
209 static inline void ss_del(struct msg_sender *mss)
211 if (mss->list.next != NULL)
212 list_del(&mss->list);
215 static void ss_wakeup(struct list_head *h, int kill)
217 struct list_head *tmp;
221 struct msg_sender *mss;
223 mss = list_entry(tmp, struct msg_sender, list);
226 mss->list.next = NULL;
227 wake_up_process(mss->tsk);
231 static void expunge_all(struct msg_queue *msq, int res)
233 struct list_head *tmp;
235 tmp = msq->q_receivers.next;
236 while (tmp != &msq->q_receivers) {
237 struct msg_receiver *msr;
239 msr = list_entry(tmp, struct msg_receiver, r_list);
242 wake_up_process(msr->r_tsk);
244 msr->r_msg = ERR_PTR(res);
249 * freeque() wakes up waiters on the sender and receiver waiting queue,
250 * removes the message queue from message queue ID IDR, and cleans up all the
251 * messages associated with this queue.
253 * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held
254 * before freeque() is called. msg_ids.rw_mutex remains locked on exit.
256 static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
258 struct list_head *tmp;
259 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
261 expunge_all(msq, -EIDRM);
262 ss_wakeup(&msq->q_senders, 1);
266 tmp = msq->q_messages.next;
267 while (tmp != &msq->q_messages) {
268 struct msg_msg *msg = list_entry(tmp, struct msg_msg, m_list);
271 atomic_dec(&ns->msg_hdrs);
274 atomic_sub(msq->q_cbytes, &ns->msg_bytes);
275 security_msg_queue_free(msq);
280 * Called with msg_ids.rw_mutex and ipcp locked.
282 static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
284 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
286 return security_msg_queue_associate(msq, msgflg);
289 asmlinkage long sys_msgget(key_t key, int msgflg)
291 struct ipc_namespace *ns;
292 struct ipc_ops msg_ops;
293 struct ipc_params msg_params;
295 ns = current->nsproxy->ipc_ns;
297 msg_ops.getnew = newque;
298 msg_ops.associate = msg_security;
299 msg_ops.more_checks = NULL;
301 msg_params.key = key;
302 msg_params.flg = msgflg;
304 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
307 static inline unsigned long
308 copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
312 return copy_to_user(buf, in, sizeof(*in));
317 memset(&out, 0, sizeof(out));
319 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
321 out.msg_stime = in->msg_stime;
322 out.msg_rtime = in->msg_rtime;
323 out.msg_ctime = in->msg_ctime;
325 if (in->msg_cbytes > USHRT_MAX)
326 out.msg_cbytes = USHRT_MAX;
328 out.msg_cbytes = in->msg_cbytes;
329 out.msg_lcbytes = in->msg_cbytes;
331 if (in->msg_qnum > USHRT_MAX)
332 out.msg_qnum = USHRT_MAX;
334 out.msg_qnum = in->msg_qnum;
336 if (in->msg_qbytes > USHRT_MAX)
337 out.msg_qbytes = USHRT_MAX;
339 out.msg_qbytes = in->msg_qbytes;
340 out.msg_lqbytes = in->msg_qbytes;
342 out.msg_lspid = in->msg_lspid;
343 out.msg_lrpid = in->msg_lrpid;
345 return copy_to_user(buf, &out, sizeof(out));
353 unsigned long qbytes;
359 static inline unsigned long
360 copy_msqid_from_user(struct msq_setbuf *out, void __user *buf, int version)
365 struct msqid64_ds tbuf;
367 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
370 out->qbytes = tbuf.msg_qbytes;
371 out->uid = tbuf.msg_perm.uid;
372 out->gid = tbuf.msg_perm.gid;
373 out->mode = tbuf.msg_perm.mode;
379 struct msqid_ds tbuf_old;
381 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
384 out->uid = tbuf_old.msg_perm.uid;
385 out->gid = tbuf_old.msg_perm.gid;
386 out->mode = tbuf_old.msg_perm.mode;
388 if (tbuf_old.msg_qbytes == 0)
389 out->qbytes = tbuf_old.msg_lqbytes;
391 out->qbytes = tbuf_old.msg_qbytes;
400 asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
402 struct kern_ipc_perm *ipcp;
403 struct msq_setbuf uninitialized_var(setbuf);
404 struct msg_queue *msq;
406 struct ipc_namespace *ns;
408 if (msqid < 0 || cmd < 0)
411 version = ipc_parse_version(&cmd);
412 ns = current->nsproxy->ipc_ns;
418 struct msginfo msginfo;
424 * We must not return kernel stack data.
425 * due to padding, it's not enough
426 * to set all member fields.
428 err = security_msg_queue_msgctl(NULL, cmd);
432 memset(&msginfo, 0, sizeof(msginfo));
433 msginfo.msgmni = ns->msg_ctlmni;
434 msginfo.msgmax = ns->msg_ctlmax;
435 msginfo.msgmnb = ns->msg_ctlmnb;
436 msginfo.msgssz = MSGSSZ;
437 msginfo.msgseg = MSGSEG;
438 down_read(&msg_ids(ns).rw_mutex);
439 if (cmd == MSG_INFO) {
440 msginfo.msgpool = msg_ids(ns).in_use;
441 msginfo.msgmap = atomic_read(&ns->msg_hdrs);
442 msginfo.msgtql = atomic_read(&ns->msg_bytes);
444 msginfo.msgmap = MSGMAP;
445 msginfo.msgpool = MSGPOOL;
446 msginfo.msgtql = MSGTQL;
448 max_id = ipc_get_maxid(&msg_ids(ns));
449 up_read(&msg_ids(ns).rw_mutex);
450 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
452 return (max_id < 0) ? 0 : max_id;
454 case MSG_STAT: /* msqid is an index rather than a msg queue id */
457 struct msqid64_ds tbuf;
463 if (cmd == MSG_STAT) {
464 msq = msg_lock(ns, msqid);
467 success_return = msq->q_perm.id;
469 msq = msg_lock_check(ns, msqid);
475 if (ipcperms(&msq->q_perm, S_IRUGO))
478 err = security_msg_queue_msgctl(msq, cmd);
482 memset(&tbuf, 0, sizeof(tbuf));
484 kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
485 tbuf.msg_stime = msq->q_stime;
486 tbuf.msg_rtime = msq->q_rtime;
487 tbuf.msg_ctime = msq->q_ctime;
488 tbuf.msg_cbytes = msq->q_cbytes;
489 tbuf.msg_qnum = msq->q_qnum;
490 tbuf.msg_qbytes = msq->q_qbytes;
491 tbuf.msg_lspid = msq->q_lspid;
492 tbuf.msg_lrpid = msq->q_lrpid;
494 if (copy_msqid_to_user(buf, &tbuf, version))
496 return success_return;
501 if (copy_msqid_from_user(&setbuf, buf, version))
510 down_write(&msg_ids(ns).rw_mutex);
511 msq = msg_lock_check_down(ns, msqid);
519 err = audit_ipc_obj(ipcp);
522 if (cmd == IPC_SET) {
523 err = audit_ipc_set_perm(setbuf.qbytes, setbuf.uid, setbuf.gid,
530 if (current->euid != ipcp->cuid &&
531 current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN))
532 /* We _could_ check for CAP_CHOWN above, but we don't */
535 err = security_msg_queue_msgctl(msq, cmd);
543 if (setbuf.qbytes > ns->msg_ctlmnb && !capable(CAP_SYS_RESOURCE))
546 msq->q_qbytes = setbuf.qbytes;
548 ipcp->uid = setbuf.uid;
549 ipcp->gid = setbuf.gid;
550 ipcp->mode = (ipcp->mode & ~S_IRWXUGO) |
551 (S_IRWXUGO & setbuf.mode);
552 msq->q_ctime = get_seconds();
553 /* sleeping receivers might be excluded by
554 * stricter permissions.
556 expunge_all(msq, -EAGAIN);
557 /* sleeping senders might be able to send
558 * due to a larger queue size.
560 ss_wakeup(&msq->q_senders, 0);
565 freeque(ns, &msq->q_perm);
570 up_write(&msg_ids(ns).rw_mutex);
580 static int testmsg(struct msg_msg *msg, long type, int mode)
586 case SEARCH_LESSEQUAL:
587 if (msg->m_type <=type)
591 if (msg->m_type == type)
594 case SEARCH_NOTEQUAL:
595 if (msg->m_type != type)
602 static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
604 struct list_head *tmp;
606 tmp = msq->q_receivers.next;
607 while (tmp != &msq->q_receivers) {
608 struct msg_receiver *msr;
610 msr = list_entry(tmp, struct msg_receiver, r_list);
612 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
613 !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
614 msr->r_msgtype, msr->r_mode)) {
616 list_del(&msr->r_list);
617 if (msr->r_maxsize < msg->m_ts) {
619 wake_up_process(msr->r_tsk);
621 msr->r_msg = ERR_PTR(-E2BIG);
624 msq->q_lrpid = task_pid_vnr(msr->r_tsk);
625 msq->q_rtime = get_seconds();
626 wake_up_process(msr->r_tsk);
637 long do_msgsnd(int msqid, long mtype, void __user *mtext,
638 size_t msgsz, int msgflg)
640 struct msg_queue *msq;
643 struct ipc_namespace *ns;
645 ns = current->nsproxy->ipc_ns;
647 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
652 msg = load_msg(mtext, msgsz);
659 msq = msg_lock_check(ns, msqid);
669 if (ipcperms(&msq->q_perm, S_IWUGO))
670 goto out_unlock_free;
672 err = security_msg_queue_msgsnd(msq, msg, msgflg);
674 goto out_unlock_free;
676 if (msgsz + msq->q_cbytes <= msq->q_qbytes &&
677 1 + msq->q_qnum <= msq->q_qbytes) {
681 /* queue full, wait: */
682 if (msgflg & IPC_NOWAIT) {
684 goto out_unlock_free;
691 ipc_lock_by_ptr(&msq->q_perm);
693 if (msq->q_perm.deleted) {
695 goto out_unlock_free;
699 if (signal_pending(current)) {
700 err = -ERESTARTNOHAND;
701 goto out_unlock_free;
705 msq->q_lspid = task_tgid_vnr(current);
706 msq->q_stime = get_seconds();
708 if (!pipelined_send(msq, msg)) {
709 /* noone is waiting for this message, enqueue it */
710 list_add_tail(&msg->m_list, &msq->q_messages);
711 msq->q_cbytes += msgsz;
713 atomic_add(msgsz, &ns->msg_bytes);
714 atomic_inc(&ns->msg_hdrs);
729 sys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, int msgflg)
733 if (get_user(mtype, &msgp->mtype))
735 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
738 static inline int convert_mode(long *msgtyp, int msgflg)
741 * find message of correct type.
742 * msgtyp = 0 => get first.
743 * msgtyp > 0 => get first message of matching type.
744 * msgtyp < 0 => get message with least type must be < abs(msgtype).
750 return SEARCH_LESSEQUAL;
752 if (msgflg & MSG_EXCEPT)
753 return SEARCH_NOTEQUAL;
757 long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
758 size_t msgsz, long msgtyp, int msgflg)
760 struct msg_queue *msq;
763 struct ipc_namespace *ns;
765 if (msqid < 0 || (long) msgsz < 0)
767 mode = convert_mode(&msgtyp, msgflg);
768 ns = current->nsproxy->ipc_ns;
770 msq = msg_lock_check(ns, msqid);
775 struct msg_receiver msr_d;
776 struct list_head *tmp;
778 msg = ERR_PTR(-EACCES);
779 if (ipcperms(&msq->q_perm, S_IRUGO))
782 msg = ERR_PTR(-EAGAIN);
783 tmp = msq->q_messages.next;
784 while (tmp != &msq->q_messages) {
785 struct msg_msg *walk_msg;
787 walk_msg = list_entry(tmp, struct msg_msg, m_list);
788 if (testmsg(walk_msg, msgtyp, mode) &&
789 !security_msg_queue_msgrcv(msq, walk_msg, current,
793 if (mode == SEARCH_LESSEQUAL &&
794 walk_msg->m_type != 1) {
796 msgtyp = walk_msg->m_type - 1;
806 * Found a suitable message.
807 * Unlink it from the queue.
809 if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
810 msg = ERR_PTR(-E2BIG);
813 list_del(&msg->m_list);
815 msq->q_rtime = get_seconds();
816 msq->q_lrpid = task_tgid_vnr(current);
817 msq->q_cbytes -= msg->m_ts;
818 atomic_sub(msg->m_ts, &ns->msg_bytes);
819 atomic_dec(&ns->msg_hdrs);
820 ss_wakeup(&msq->q_senders, 0);
824 /* No message waiting. Wait for a message */
825 if (msgflg & IPC_NOWAIT) {
826 msg = ERR_PTR(-ENOMSG);
829 list_add_tail(&msr_d.r_list, &msq->q_receivers);
830 msr_d.r_tsk = current;
831 msr_d.r_msgtype = msgtyp;
833 if (msgflg & MSG_NOERROR)
834 msr_d.r_maxsize = INT_MAX;
836 msr_d.r_maxsize = msgsz;
837 msr_d.r_msg = ERR_PTR(-EAGAIN);
838 current->state = TASK_INTERRUPTIBLE;
843 /* Lockless receive, part 1:
844 * Disable preemption. We don't hold a reference to the queue
845 * and getting a reference would defeat the idea of a lockless
846 * operation, thus the code relies on rcu to guarantee the
848 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
849 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
850 * rcu_read_lock() prevents preemption between reading r_msg
851 * and the spin_lock() inside ipc_lock_by_ptr().
855 /* Lockless receive, part 2:
856 * Wait until pipelined_send or expunge_all are outside of
857 * wake_up_process(). There is a race with exit(), see
858 * ipc/mqueue.c for the details.
860 msg = (struct msg_msg*)msr_d.r_msg;
861 while (msg == NULL) {
863 msg = (struct msg_msg *)msr_d.r_msg;
866 /* Lockless receive, part 3:
867 * If there is a message or an error then accept it without
870 if (msg != ERR_PTR(-EAGAIN)) {
875 /* Lockless receive, part 3:
876 * Acquire the queue spinlock.
878 ipc_lock_by_ptr(&msq->q_perm);
881 /* Lockless receive, part 4:
882 * Repeat test after acquiring the spinlock.
884 msg = (struct msg_msg*)msr_d.r_msg;
885 if (msg != ERR_PTR(-EAGAIN))
888 list_del(&msr_d.r_list);
889 if (signal_pending(current)) {
890 msg = ERR_PTR(-ERESTARTNOHAND);
899 msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz;
900 *pmtype = msg->m_type;
901 if (store_msg(mtext, msg, msgsz))
909 asmlinkage long sys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
910 long msgtyp, int msgflg)
914 err = do_msgrcv(msqid, &mtype, msgp->mtext, msgsz, msgtyp, msgflg);
918 if (put_user(mtype, &msgp->mtype))
924 #ifdef CONFIG_PROC_FS
925 static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
927 struct msg_queue *msq = it;
930 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",