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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/ipc/msg.c
Ingo Molnar5a06a362006-07-30 03:04:11 -07003 * Copyright (C) 1992 Krishna Balasubramanian
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 *
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
10 *
11 * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
12 *
13 * mostly rewritten, threaded and wake-one semantics added
14 * MSGMAX limit removed, sysctl's added
Christian Kujau624dffc2006-01-15 02:43:54 +010015 * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
Steve Grubb073115d2006-04-02 17:07:33 -040016 *
17 * support for audit of ipc object properties and permission changes
18 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
Kirill Korotaev1e786932006-10-02 02:18:21 -070019 *
20 * namespaces support
21 * OpenVZ, SWsoft Inc.
22 * Pavel Emelianov <xemul@openvz.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023 */
24
Randy.Dunlapc59ede72006-01-11 12:17:46 -080025#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/msg.h>
27#include <linux/spinlock.h>
28#include <linux/init.h>
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -070029#include <linux/mm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#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>
Mike Waychison19b49462005-09-06 15:17:10 -070036#include <linux/seq_file.h>
Nadia Derbey3e148c72007-10-18 23:40:54 -070037#include <linux/rwsem.h>
Kirill Korotaev1e786932006-10-02 02:18:21 -070038#include <linux/nsproxy.h>
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080039#include <linux/ipc_namespace.h>
Ingo Molnar5f921ae2006-03-26 01:37:17 -080040
Linus Torvalds1da177e2005-04-16 15:20:36 -070041#include <asm/current.h>
Paul McQuade7153e402014-06-06 14:37:37 -070042#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#include "util.h"
44
Davidlohr Bueso4bb66572014-06-06 14:37:46 -070045/* one msg_receiver structure for each sleeping receiver */
Linus Torvalds1da177e2005-04-16 15:20:36 -070046struct msg_receiver {
Ingo Molnar5a06a362006-07-30 03:04:11 -070047 struct list_head r_list;
48 struct task_struct *r_tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
Ingo Molnar5a06a362006-07-30 03:04:11 -070050 int r_mode;
51 long r_msgtype;
52 long r_maxsize;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
Davidlohr Bueso4bb66572014-06-06 14:37:46 -070054 /*
55 * Mark r_msg volatile so that the compiler
56 * does not try to get smart and optimize
57 * it. We rely on this for the lockless
58 * receive algorithm.
59 */
Linus Torvalds80491eb2006-11-04 09:55:00 -080060 struct msg_msg *volatile r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -070061};
62
63/* one msg_sender for each sleeping sender */
64struct msg_sender {
Ingo Molnar5a06a362006-07-30 03:04:11 -070065 struct list_head list;
66 struct task_struct *tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -070067};
68
69#define SEARCH_ANY 1
70#define SEARCH_EQUAL 2
71#define SEARCH_NOTEQUAL 3
72#define SEARCH_LESSEQUAL 4
Peter Hurley8ac6ed52013-04-30 19:14:54 -070073#define SEARCH_NUMBER 5
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080075#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
Kirill Korotaev1e786932006-10-02 02:18:21 -070076
Davidlohr Buesoa5001a02013-07-08 16:01:15 -070077static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
78{
Davidlohr Bueso55b7ae52015-06-30 14:58:42 -070079 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&msg_ids(ns), id);
Davidlohr Buesoa5001a02013-07-08 16:01:15 -070080
81 if (IS_ERR(ipcp))
82 return ERR_CAST(ipcp);
83
84 return container_of(ipcp, struct msg_queue, q_perm);
85}
86
87static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
88 int id)
89{
90 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
91
92 if (IS_ERR(ipcp))
93 return ERR_CAST(ipcp);
94
95 return container_of(ipcp, struct msg_queue, q_perm);
96}
97
Nadia Derbey7ca7e562007-10-18 23:40:48 -070098static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
99{
100 ipc_rmid(&msg_ids(ns), &s->q_perm);
101}
102
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700103static void msg_rcu_free(struct rcu_head *head)
104{
105 struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
106 struct msg_queue *msq = ipc_rcu_to_struct(p);
107
108 security_msg_queue_free(msq);
109 ipc_rcu_free(head);
110}
111
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700112/**
113 * newque - Create a new msg queue
114 * @ns: namespace
115 * @params: ptr to the structure that contains the key and msgflg
116 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700117 * Called with msg_ids.rwsem held (writer)
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700118 */
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700119static int newque(struct ipc_namespace *ns, struct ipc_params *params)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 struct msg_queue *msq;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700122 int id, retval;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700123 key_t key = params->key;
124 int msgflg = params->flg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125
Ingo Molnar5a06a362006-07-30 03:04:11 -0700126 msq = ipc_rcu_alloc(sizeof(*msq));
127 if (!msq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 return -ENOMEM;
129
Ingo Molnar5a06a362006-07-30 03:04:11 -0700130 msq->q_perm.mode = msgflg & S_IRWXUGO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 msq->q_perm.key = key;
132
133 msq->q_perm.security = NULL;
134 retval = security_msg_queue_alloc(msq);
135 if (retval) {
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700136 ipc_rcu_putref(msq, ipc_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 return retval;
138 }
139
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 msq->q_stime = msq->q_rtime = 0;
141 msq->q_ctime = get_seconds();
142 msq->q_cbytes = msq->q_qnum = 0;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700143 msq->q_qbytes = ns->msg_ctlmnb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 msq->q_lspid = msq->q_lrpid = 0;
145 INIT_LIST_HEAD(&msq->q_messages);
146 INIT_LIST_HEAD(&msq->q_receivers);
147 INIT_LIST_HEAD(&msq->q_senders);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700148
Linus Torvaldsb9a53222015-09-30 12:48:40 -0400149 /* ipc_addid() locks msq upon success. */
150 id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
151 if (id < 0) {
152 ipc_rcu_putref(msq, msg_rcu_free);
153 return id;
154 }
155
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -0700156 ipc_unlock_object(&msq->q_perm);
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700157 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700159 return msq->q_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160}
161
Ingo Molnar5a06a362006-07-30 03:04:11 -0700162static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700164 mss->tsk = current;
Davidlohr Buesof75a2f32014-06-06 14:37:44 -0700165 __set_current_state(TASK_INTERRUPTIBLE);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700166 list_add_tail(&mss->list, &msq->q_senders);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167}
168
Ingo Molnar5a06a362006-07-30 03:04:11 -0700169static inline void ss_del(struct msg_sender *mss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700171 if (mss->list.next != NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 list_del(&mss->list);
173}
174
Ingo Molnar5a06a362006-07-30 03:04:11 -0700175static void ss_wakeup(struct list_head *h, int kill)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176{
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700177 struct msg_sender *mss, *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700179 list_for_each_entry_safe(mss, t, h, list) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700180 if (kill)
181 mss->list.next = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 wake_up_process(mss->tsk);
183 }
184}
185
Ingo Molnar5a06a362006-07-30 03:04:11 -0700186static void expunge_all(struct msg_queue *msq, int res)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187{
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700188 struct msg_receiver *msr, *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700190 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
Davidlohr Buesoffa571d2014-01-27 17:07:10 -0800191 msr->r_msg = NULL; /* initialize expunge ordering */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 wake_up_process(msr->r_tsk);
Davidlohr Buesoffa571d2014-01-27 17:07:10 -0800193 /*
194 * Ensure that the wakeup is visible before setting r_msg as
195 * the receiving end depends on it: either spinning on a nil,
196 * or dealing with -EAGAIN cases. See lockless receive part 1
197 * and 2 in do_msgrcv().
198 */
Davidlohr Buesoff35e5e2015-06-30 14:58:39 -0700199 smp_wmb(); /* barrier (B) */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 msr->r_msg = ERR_PTR(res);
201 }
202}
Ingo Molnar5a06a362006-07-30 03:04:11 -0700203
204/*
205 * freeque() wakes up waiters on the sender and receiver waiting queue,
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700206 * removes the message queue from message queue ID IDR, and cleans up all the
207 * messages associated with this queue.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700209 * msg_ids.rwsem (writer) and the spinlock for this message queue are held
210 * before freeque() is called. msg_ids.rwsem remains locked on exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 */
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800212static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213{
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700214 struct msg_msg *msg, *t;
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800215 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
Ingo Molnar5a06a362006-07-30 03:04:11 -0700217 expunge_all(msq, -EIDRM);
218 ss_wakeup(&msq->q_senders, 1);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700219 msg_rmid(ns, msq);
Davidlohr Bueso47187872013-09-11 14:26:25 -0700220 ipc_unlock_object(&msq->q_perm);
221 rcu_read_unlock();
Ingo Molnar5a06a362006-07-30 03:04:11 -0700222
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700223 list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700224 atomic_dec(&ns->msg_hdrs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 free_msg(msg);
226 }
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700227 atomic_sub(msq->q_cbytes, &ns->msg_bytes);
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700228 ipc_rcu_putref(msq, msg_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229}
230
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700231/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700232 * Called with msg_ids.rwsem and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700233 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700234static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700235{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700236 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
237
238 return security_msg_queue_associate(msq, msgflg);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700239}
240
Heiko Carstense48fbb62009-01-14 14:14:26 +0100241SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242{
Kirill Korotaev1e786932006-10-02 02:18:21 -0700243 struct ipc_namespace *ns;
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700244 static const struct ipc_ops msg_ops = {
245 .getnew = newque,
246 .associate = msg_security,
247 };
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700248 struct ipc_params msg_params;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700249
250 ns = current->nsproxy->ipc_ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700251
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700252 msg_params.key = key;
253 msg_params.flg = msgflg;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700254
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700255 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256}
257
Ingo Molnar5a06a362006-07-30 03:04:11 -0700258static inline unsigned long
259copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260{
Manfred Spraul239521f2014-01-27 17:07:04 -0800261 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 case IPC_64:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700263 return copy_to_user(buf, in, sizeof(*in));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 case IPC_OLD:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700265 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 struct msqid_ds out;
267
Ingo Molnar5a06a362006-07-30 03:04:11 -0700268 memset(&out, 0, sizeof(out));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269
270 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
271
272 out.msg_stime = in->msg_stime;
273 out.msg_rtime = in->msg_rtime;
274 out.msg_ctime = in->msg_ctime;
275
Alexey Dobriyan4be929b2010-05-24 14:33:03 -0700276 if (in->msg_cbytes > USHRT_MAX)
277 out.msg_cbytes = USHRT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 else
279 out.msg_cbytes = in->msg_cbytes;
280 out.msg_lcbytes = in->msg_cbytes;
281
Alexey Dobriyan4be929b2010-05-24 14:33:03 -0700282 if (in->msg_qnum > USHRT_MAX)
283 out.msg_qnum = USHRT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 else
285 out.msg_qnum = in->msg_qnum;
286
Alexey Dobriyan4be929b2010-05-24 14:33:03 -0700287 if (in->msg_qbytes > USHRT_MAX)
288 out.msg_qbytes = USHRT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 else
290 out.msg_qbytes = in->msg_qbytes;
291 out.msg_lqbytes = in->msg_qbytes;
292
293 out.msg_lspid = in->msg_lspid;
294 out.msg_lrpid = in->msg_lrpid;
295
Ingo Molnar5a06a362006-07-30 03:04:11 -0700296 return copy_to_user(buf, &out, sizeof(out));
297 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 default:
299 return -EINVAL;
300 }
301}
302
Ingo Molnar5a06a362006-07-30 03:04:11 -0700303static inline unsigned long
Pierre Peiffer016d7132008-04-29 01:00:50 -0700304copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305{
Manfred Spraul239521f2014-01-27 17:07:04 -0800306 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 case IPC_64:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700308 if (copy_from_user(out, buf, sizeof(*out)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 case IPC_OLD:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700312 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 struct msqid_ds tbuf_old;
314
Ingo Molnar5a06a362006-07-30 03:04:11 -0700315 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 return -EFAULT;
317
Manfred Spraul239521f2014-01-27 17:07:04 -0800318 out->msg_perm.uid = tbuf_old.msg_perm.uid;
319 out->msg_perm.gid = tbuf_old.msg_perm.gid;
320 out->msg_perm.mode = tbuf_old.msg_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321
Ingo Molnar5a06a362006-07-30 03:04:11 -0700322 if (tbuf_old.msg_qbytes == 0)
Pierre Peiffer016d7132008-04-29 01:00:50 -0700323 out->msg_qbytes = tbuf_old.msg_lqbytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 else
Pierre Peiffer016d7132008-04-29 01:00:50 -0700325 out->msg_qbytes = tbuf_old.msg_qbytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
327 return 0;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700328 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 default:
330 return -EINVAL;
331 }
332}
333
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700334/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700335 * This function handles some msgctl commands which require the rwsem
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700336 * to be held in write mode.
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700337 * NOTE: no locks must be held, the rwsem is taken inside this function.
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700338 */
339static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
340 struct msqid_ds __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 struct kern_ipc_perm *ipcp;
Felipe Contrerasf1970c42009-10-19 01:54:29 +0300343 struct msqid64_ds uninitialized_var(msqid64);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700344 struct msg_queue *msq;
345 int err;
346
347 if (cmd == IPC_SET) {
Pierre Peiffer016d7132008-04-29 01:00:50 -0700348 if (copy_msqid_from_user(&msqid64, buf, version))
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700349 return -EFAULT;
350 }
351
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700352 down_write(&msg_ids(ns).rwsem);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700353 rcu_read_lock();
354
Davidlohr Bueso15724ec2013-07-08 16:01:13 -0700355 ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
356 &msqid64.msg_perm, msqid64.msg_qbytes);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700357 if (IS_ERR(ipcp)) {
358 err = PTR_ERR(ipcp);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700359 goto out_unlock1;
360 }
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700361
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700362 msq = container_of(ipcp, struct msg_queue, q_perm);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700363
364 err = security_msg_queue_msgctl(msq, cmd);
365 if (err)
Davidlohr Bueso15724ec2013-07-08 16:01:13 -0700366 goto out_unlock1;
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700367
368 switch (cmd) {
369 case IPC_RMID:
Davidlohr Bueso15724ec2013-07-08 16:01:13 -0700370 ipc_lock_object(&msq->q_perm);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700371 /* freeque unlocks the ipc object and rcu */
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700372 freeque(ns, ipcp);
373 goto out_up;
374 case IPC_SET:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700375 if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700376 !capable(CAP_SYS_RESOURCE)) {
377 err = -EPERM;
Davidlohr Bueso15724ec2013-07-08 16:01:13 -0700378 goto out_unlock1;
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700379 }
380
Davidlohr Bueso15724ec2013-07-08 16:01:13 -0700381 ipc_lock_object(&msq->q_perm);
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800382 err = ipc_update_perm(&msqid64.msg_perm, ipcp);
383 if (err)
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700384 goto out_unlock0;
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800385
Pierre Peiffer016d7132008-04-29 01:00:50 -0700386 msq->q_qbytes = msqid64.msg_qbytes;
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700387
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700388 msq->q_ctime = get_seconds();
389 /* sleeping receivers might be excluded by
390 * stricter permissions.
391 */
392 expunge_all(msq, -EAGAIN);
393 /* sleeping senders might be able to send
394 * due to a larger queue size.
395 */
396 ss_wakeup(&msq->q_senders, 0);
397 break;
398 default:
399 err = -EINVAL;
Davidlohr Bueso15724ec2013-07-08 16:01:13 -0700400 goto out_unlock1;
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700401 }
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700402
403out_unlock0:
404 ipc_unlock_object(&msq->q_perm);
405out_unlock1:
406 rcu_read_unlock();
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700407out_up:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700408 up_write(&msg_ids(ns).rwsem);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700409 return err;
410}
411
Davidlohr Bueso2cafed32013-07-08 16:01:14 -0700412static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
413 int cmd, int version, void __user *buf)
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700414{
Davidlohr Bueso2cafed32013-07-08 16:01:14 -0700415 int err;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700416 struct msg_queue *msq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417
418 switch (cmd) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700419 case IPC_INFO:
420 case MSG_INFO:
421 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 struct msginfo msginfo;
423 int max_id;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700424
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 if (!buf)
426 return -EFAULT;
Davidlohr Bueso2cafed32013-07-08 16:01:14 -0700427
Ingo Molnar5a06a362006-07-30 03:04:11 -0700428 /*
429 * We must not return kernel stack data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 * due to padding, it's not enough
431 * to set all member fields.
432 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 err = security_msg_queue_msgctl(NULL, cmd);
434 if (err)
435 return err;
436
Ingo Molnar5a06a362006-07-30 03:04:11 -0700437 memset(&msginfo, 0, sizeof(msginfo));
Kirill Korotaev1e786932006-10-02 02:18:21 -0700438 msginfo.msgmni = ns->msg_ctlmni;
439 msginfo.msgmax = ns->msg_ctlmax;
440 msginfo.msgmnb = ns->msg_ctlmnb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 msginfo.msgssz = MSGSSZ;
442 msginfo.msgseg = MSGSEG;
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700443 down_read(&msg_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 if (cmd == MSG_INFO) {
Kirill Korotaev1e786932006-10-02 02:18:21 -0700445 msginfo.msgpool = msg_ids(ns).in_use;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700446 msginfo.msgmap = atomic_read(&ns->msg_hdrs);
447 msginfo.msgtql = atomic_read(&ns->msg_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 } else {
449 msginfo.msgmap = MSGMAP;
450 msginfo.msgpool = MSGPOOL;
451 msginfo.msgtql = MSGTQL;
452 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700453 max_id = ipc_get_maxid(&msg_ids(ns));
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700454 up_read(&msg_ids(ns).rwsem);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700455 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 return -EFAULT;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700457 return (max_id < 0) ? 0 : max_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 }
Davidlohr Bueso2cafed32013-07-08 16:01:14 -0700459
460 case MSG_STAT:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 case IPC_STAT:
462 {
463 struct msqid64_ds tbuf;
464 int success_return;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700465
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 if (!buf)
467 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468
Davidlohr Buesoac0ba202013-07-08 16:01:16 -0700469 memset(&tbuf, 0, sizeof(tbuf));
470
471 rcu_read_lock();
Ingo Molnar5a06a362006-07-30 03:04:11 -0700472 if (cmd == MSG_STAT) {
Davidlohr Buesoac0ba202013-07-08 16:01:16 -0700473 msq = msq_obtain_object(ns, msqid);
474 if (IS_ERR(msq)) {
475 err = PTR_ERR(msq);
476 goto out_unlock;
477 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700478 success_return = msq->q_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 } else {
Davidlohr Buesoac0ba202013-07-08 16:01:16 -0700480 msq = msq_obtain_object_check(ns, msqid);
481 if (IS_ERR(msq)) {
482 err = PTR_ERR(msq);
483 goto out_unlock;
484 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 success_return = 0;
486 }
Davidlohr Buesoac0ba202013-07-08 16:01:16 -0700487
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 err = -EACCES;
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700489 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 goto out_unlock;
491
492 err = security_msg_queue_msgctl(msq, cmd);
493 if (err)
494 goto out_unlock;
495
496 kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
497 tbuf.msg_stime = msq->q_stime;
498 tbuf.msg_rtime = msq->q_rtime;
499 tbuf.msg_ctime = msq->q_ctime;
500 tbuf.msg_cbytes = msq->q_cbytes;
501 tbuf.msg_qnum = msq->q_qnum;
502 tbuf.msg_qbytes = msq->q_qbytes;
503 tbuf.msg_lspid = msq->q_lspid;
504 tbuf.msg_lrpid = msq->q_lrpid;
Davidlohr Buesoac0ba202013-07-08 16:01:16 -0700505 rcu_read_unlock();
506
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 if (copy_msqid_to_user(buf, &tbuf, version))
508 return -EFAULT;
509 return success_return;
510 }
Davidlohr Bueso2cafed32013-07-08 16:01:14 -0700511
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 default:
Davidlohr Bueso2cafed32013-07-08 16:01:14 -0700513 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 }
515
Davidlohr Bueso2cafed32013-07-08 16:01:14 -0700516 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517out_unlock:
Davidlohr Buesoac0ba202013-07-08 16:01:16 -0700518 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 return err;
520}
521
Davidlohr Bueso2cafed32013-07-08 16:01:14 -0700522SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
523{
524 int version;
525 struct ipc_namespace *ns;
526
527 if (msqid < 0 || cmd < 0)
528 return -EINVAL;
529
530 version = ipc_parse_version(&cmd);
531 ns = current->nsproxy->ipc_ns;
532
533 switch (cmd) {
534 case IPC_INFO:
535 case MSG_INFO:
536 case MSG_STAT: /* msqid is an index rather than a msg queue id */
537 case IPC_STAT:
538 return msgctl_nolock(ns, msqid, cmd, version, buf);
539 case IPC_SET:
540 case IPC_RMID:
541 return msgctl_down(ns, msqid, cmd, buf, version);
542 default:
543 return -EINVAL;
544 }
545}
546
Ingo Molnar5a06a362006-07-30 03:04:11 -0700547static int testmsg(struct msg_msg *msg, long type, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548{
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700549 switch (mode) {
550 case SEARCH_ANY:
551 case SEARCH_NUMBER:
552 return 1;
553 case SEARCH_LESSEQUAL:
554 if (msg->m_type <= type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 return 1;
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700556 break;
557 case SEARCH_EQUAL:
558 if (msg->m_type == type)
559 return 1;
560 break;
561 case SEARCH_NOTEQUAL:
562 if (msg->m_type != type)
563 return 1;
564 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 }
566 return 0;
567}
568
Ingo Molnar5a06a362006-07-30 03:04:11 -0700569static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570{
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700571 struct msg_receiver *msr, *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700573 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700574 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
575 !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
576 msr->r_msgtype, msr->r_mode)) {
577
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 list_del(&msr->r_list);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700579 if (msr->r_maxsize < msg->m_ts) {
Davidlohr Buesoffa571d2014-01-27 17:07:10 -0800580 /* initialize pipelined send ordering */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 msr->r_msg = NULL;
582 wake_up_process(msr->r_tsk);
Davidlohr Buesoff35e5e2015-06-30 14:58:39 -0700583 /* barrier (B) see barrier comment below */
584 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 msr->r_msg = ERR_PTR(-E2BIG);
586 } else {
587 msr->r_msg = NULL;
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700588 msq->q_lrpid = task_pid_vnr(msr->r_tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 msq->q_rtime = get_seconds();
590 wake_up_process(msr->r_tsk);
Davidlohr Buesoffa571d2014-01-27 17:07:10 -0800591 /*
592 * Ensure that the wakeup is visible before
Davidlohr Buesoff35e5e2015-06-30 14:58:39 -0700593 * setting r_msg, as the receiving can otherwise
594 * exit - once r_msg is set, the receiver can
595 * continue. See lockless receive part 1 and 2
596 * in do_msgrcv(). Barrier (B).
Davidlohr Buesoffa571d2014-01-27 17:07:10 -0800597 */
Davidlohr Buesoff35e5e2015-06-30 14:58:39 -0700598 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 msr->r_msg = msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700600
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 return 1;
602 }
603 }
604 }
Davidlohr Buesoffa571d2014-01-27 17:07:10 -0800605
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 return 0;
607}
608
suzuki651971c2006-12-06 20:37:48 -0800609long do_msgsnd(int msqid, long mtype, void __user *mtext,
610 size_t msgsz, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611{
612 struct msg_queue *msq;
613 struct msg_msg *msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 int err;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700615 struct ipc_namespace *ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700616
Kirill Korotaev1e786932006-10-02 02:18:21 -0700617 ns = current->nsproxy->ipc_ns;
618
619 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 if (mtype < 1)
622 return -EINVAL;
623
suzuki651971c2006-12-06 20:37:48 -0800624 msg = load_msg(mtext, msgsz);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700625 if (IS_ERR(msg))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 return PTR_ERR(msg);
627
628 msg->m_type = mtype;
629 msg->m_ts = msgsz;
630
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700631 rcu_read_lock();
632 msq = msq_obtain_object_check(ns, msqid);
Nadia Derbey023a5352007-10-18 23:40:51 -0700633 if (IS_ERR(msq)) {
634 err = PTR_ERR(msq);
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700635 goto out_unlock1;
Nadia Derbey023a5352007-10-18 23:40:51 -0700636 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637
Manfred Spraulbebcb922013-09-03 16:00:08 +0200638 ipc_lock_object(&msq->q_perm);
639
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 for (;;) {
641 struct msg_sender s;
642
Ingo Molnar5a06a362006-07-30 03:04:11 -0700643 err = -EACCES;
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700644 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
Manfred Spraulbebcb922013-09-03 16:00:08 +0200645 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646
Davidlohr Bueso4271b052013-09-30 13:45:26 -0700647 /* raced with RMID? */
Rafael Aquini0f3d2b02014-01-27 17:07:01 -0800648 if (!ipc_valid_object(&msq->q_perm)) {
Davidlohr Bueso4271b052013-09-30 13:45:26 -0700649 err = -EIDRM;
650 goto out_unlock0;
651 }
652
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 err = security_msg_queue_msgsnd(msq, msg, msgflg);
654 if (err)
Manfred Spraulbebcb922013-09-03 16:00:08 +0200655 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656
Ingo Molnar5a06a362006-07-30 03:04:11 -0700657 if (msgsz + msq->q_cbytes <= msq->q_qbytes &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 1 + msq->q_qnum <= msq->q_qbytes) {
659 break;
660 }
661
662 /* queue full, wait: */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700663 if (msgflg & IPC_NOWAIT) {
664 err = -EAGAIN;
Manfred Spraulbebcb922013-09-03 16:00:08 +0200665 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 }
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700667
Davidlohr Buesoffa571d2014-01-27 17:07:10 -0800668 /* enqueue the sender and prepare to block */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 ss_add(msq, &s);
Rik van Riel6062a8d2013-04-30 19:15:44 -0700670
671 if (!ipc_rcu_getref(msq)) {
672 err = -EIDRM;
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700673 goto out_unlock0;
Rik van Riel6062a8d2013-04-30 19:15:44 -0700674 }
675
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700676 ipc_unlock_object(&msq->q_perm);
677 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 schedule();
679
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700680 rcu_read_lock();
681 ipc_lock_object(&msq->q_perm);
682
Fabian Frederick9b24fef2016-08-02 14:03:07 -0700683 ipc_rcu_putref(msq, msg_rcu_free);
Rafael Aquini0f3d2b02014-01-27 17:07:01 -0800684 /* raced with RMID? */
685 if (!ipc_valid_object(&msq->q_perm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 err = -EIDRM;
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700687 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 }
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700689
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 ss_del(&s);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700691
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 if (signal_pending(current)) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700693 err = -ERESTARTNOHAND;
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700694 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 }
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700696
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 }
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700698 msq->q_lspid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 msq->q_stime = get_seconds();
700
Ingo Molnar5a06a362006-07-30 03:04:11 -0700701 if (!pipelined_send(msq, msg)) {
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300702 /* no one is waiting for this message, enqueue it */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700703 list_add_tail(&msg->m_list, &msq->q_messages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 msq->q_cbytes += msgsz;
705 msq->q_qnum++;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700706 atomic_add(msgsz, &ns->msg_bytes);
707 atomic_inc(&ns->msg_hdrs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700709
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 err = 0;
711 msg = NULL;
712
Davidlohr Bueso3dd1f782013-07-08 16:01:17 -0700713out_unlock0:
714 ipc_unlock_object(&msq->q_perm);
715out_unlock1:
716 rcu_read_unlock();
Ingo Molnar5a06a362006-07-30 03:04:11 -0700717 if (msg != NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 free_msg(msg);
719 return err;
720}
721
Heiko Carstense48fbb62009-01-14 14:14:26 +0100722SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
723 int, msgflg)
suzuki651971c2006-12-06 20:37:48 -0800724{
725 long mtype;
726
727 if (get_user(mtype, &msgp->mtype))
728 return -EFAULT;
729 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
730}
731
Ingo Molnar5a06a362006-07-30 03:04:11 -0700732static inline int convert_mode(long *msgtyp, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733{
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700734 if (msgflg & MSG_COPY)
735 return SEARCH_NUMBER;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700736 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737 * find message of correct type.
738 * msgtyp = 0 => get first.
739 * msgtyp > 0 => get first message of matching type.
Ingo Molnar5a06a362006-07-30 03:04:11 -0700740 * msgtyp < 0 => get message with least type must be < abs(msgtype).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700742 if (*msgtyp == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 return SEARCH_ANY;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700744 if (*msgtyp < 0) {
745 *msgtyp = -*msgtyp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 return SEARCH_LESSEQUAL;
747 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700748 if (msgflg & MSG_EXCEPT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 return SEARCH_NOTEQUAL;
750 return SEARCH_EQUAL;
751}
752
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800753static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
754{
755 struct msgbuf __user *msgp = dest;
756 size_t msgsz;
757
758 if (put_user(msg->m_type, &msgp->mtype))
759 return -EFAULT;
760
761 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
762 if (store_msg(msgp->mtext, msg, msgsz))
763 return -EFAULT;
764 return msgsz;
765}
766
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800767#ifdef CONFIG_CHECKPOINT_RESTORE
Stanislav Kinsbursky3fcfe782013-01-04 15:35:03 -0800768/*
769 * This function creates new kernel message structure, large enough to store
770 * bufsz message bytes.
771 */
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700772static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800773{
774 struct msg_msg *copy;
775
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800776 /*
777 * Create dummy message to copy real message to.
778 */
779 copy = load_msg(buf, bufsz);
780 if (!IS_ERR(copy))
781 copy->m_ts = bufsz;
782 return copy;
783}
784
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800785static inline void free_copy(struct msg_msg *copy)
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800786{
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800787 if (copy)
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800788 free_msg(copy);
789}
790#else
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700791static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
Stanislav Kinsburskyb30efe22013-01-04 15:35:00 -0800792{
793 return ERR_PTR(-ENOSYS);
794}
795
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800796static inline void free_copy(struct msg_msg *copy)
797{
798}
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800799#endif
800
Peter Hurleydaaf74c2013-04-30 19:15:04 -0700801static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
802{
Svenning Sørensen368ae532013-08-28 16:35:17 -0700803 struct msg_msg *msg, *found = NULL;
Peter Hurleydaaf74c2013-04-30 19:15:04 -0700804 long count = 0;
805
806 list_for_each_entry(msg, &msq->q_messages, m_list) {
807 if (testmsg(msg, *msgtyp, mode) &&
808 !security_msg_queue_msgrcv(msq, msg, current,
809 *msgtyp, mode)) {
810 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
811 *msgtyp = msg->m_type - 1;
Svenning Sørensen368ae532013-08-28 16:35:17 -0700812 found = msg;
Peter Hurleydaaf74c2013-04-30 19:15:04 -0700813 } else if (mode == SEARCH_NUMBER) {
814 if (*msgtyp == count)
815 return msg;
816 } else
817 return msg;
818 count++;
819 }
820 }
821
Svenning Sørensen368ae532013-08-28 16:35:17 -0700822 return found ?: ERR_PTR(-EAGAIN);
Peter Hurleydaaf74c2013-04-30 19:15:04 -0700823}
824
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700825long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg,
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800826 long (*msg_handler)(void __user *, struct msg_msg *, size_t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 int mode;
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700829 struct msg_queue *msq;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700830 struct ipc_namespace *ns;
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700831 struct msg_msg *msg, *copy = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832
Peter Hurley88b9e452013-03-08 12:43:27 -0800833 ns = current->nsproxy->ipc_ns;
834
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800835 if (msqid < 0 || (long) bufsz < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836 return -EINVAL;
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700837
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800838 if (msgflg & MSG_COPY) {
Michael Kerrisk4f87dac2014-03-10 14:46:07 +0100839 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
840 return -EINVAL;
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700841 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800842 if (IS_ERR(copy))
843 return PTR_ERR(copy);
844 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700845 mode = convert_mode(&msgtyp, msgflg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700847 rcu_read_lock();
848 msq = msq_obtain_object_check(ns, msqid);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800849 if (IS_ERR(msq)) {
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700850 rcu_read_unlock();
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800851 free_copy(copy);
Nadia Derbey023a5352007-10-18 23:40:51 -0700852 return PTR_ERR(msq);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800853 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854
855 for (;;) {
856 struct msg_receiver msr_d;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857
858 msg = ERR_PTR(-EACCES);
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700859 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700860 goto out_unlock1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700862 ipc_lock_object(&msq->q_perm);
Davidlohr Bueso4271b052013-09-30 13:45:26 -0700863
864 /* raced with RMID? */
Rafael Aquini0f3d2b02014-01-27 17:07:01 -0800865 if (!ipc_valid_object(&msq->q_perm)) {
Davidlohr Bueso4271b052013-09-30 13:45:26 -0700866 msg = ERR_PTR(-EIDRM);
867 goto out_unlock0;
868 }
869
Peter Hurleydaaf74c2013-04-30 19:15:04 -0700870 msg = find_msg(msq, &msgtyp, mode);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700871 if (!IS_ERR(msg)) {
872 /*
873 * Found a suitable message.
874 * Unlink it from the queue.
875 */
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800876 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 msg = ERR_PTR(-E2BIG);
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700878 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 }
Stanislav Kinsbursky3fcfe782013-01-04 15:35:03 -0800880 /*
881 * If we are copying, then do not unlink message and do
882 * not update queue parameters.
883 */
Peter Hurley852028a2013-04-30 19:14:48 -0700884 if (msgflg & MSG_COPY) {
885 msg = copy_msg(msg, copy);
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700886 goto out_unlock0;
Peter Hurley852028a2013-04-30 19:14:48 -0700887 }
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700888
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 list_del(&msg->m_list);
890 msq->q_qnum--;
891 msq->q_rtime = get_seconds();
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700892 msq->q_lrpid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 msq->q_cbytes -= msg->m_ts;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700894 atomic_sub(msg->m_ts, &ns->msg_bytes);
895 atomic_dec(&ns->msg_hdrs);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700896 ss_wakeup(&msq->q_senders, 0);
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700897
898 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 }
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700900
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 /* No message waiting. Wait for a message */
902 if (msgflg & IPC_NOWAIT) {
903 msg = ERR_PTR(-ENOMSG);
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700904 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 }
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700906
Ingo Molnar5a06a362006-07-30 03:04:11 -0700907 list_add_tail(&msr_d.r_list, &msq->q_receivers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 msr_d.r_tsk = current;
909 msr_d.r_msgtype = msgtyp;
910 msr_d.r_mode = mode;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700911 if (msgflg & MSG_NOERROR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 msr_d.r_maxsize = INT_MAX;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700913 else
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800914 msr_d.r_maxsize = bufsz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915 msr_d.r_msg = ERR_PTR(-EAGAIN);
Davidlohr Buesof75a2f32014-06-06 14:37:44 -0700916 __set_current_state(TASK_INTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700918 ipc_unlock_object(&msq->q_perm);
919 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 schedule();
921
922 /* Lockless receive, part 1:
923 * Disable preemption. We don't hold a reference to the queue
924 * and getting a reference would defeat the idea of a lockless
925 * operation, thus the code relies on rcu to guarantee the
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300926 * existence of msq:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
928 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
929 * rcu_read_lock() prevents preemption between reading r_msg
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700930 * and acquiring the q_perm.lock in ipc_lock_object().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 */
932 rcu_read_lock();
933
934 /* Lockless receive, part 2:
935 * Wait until pipelined_send or expunge_all are outside of
936 * wake_up_process(). There is a race with exit(), see
Davidlohr Buesoff35e5e2015-06-30 14:58:39 -0700937 * ipc/mqueue.c for the details. The correct serialization
938 * ensures that a receiver cannot continue without the wakeup
939 * being visibible _before_ setting r_msg:
940 *
941 * CPU 0 CPU 1
942 * <loop receiver>
943 * smp_rmb(); (A) <-- pair -. <waker thread>
944 * <load ->r_msg> | msr->r_msg = NULL;
945 * | wake_up_process();
946 * <continue> `------> smp_wmb(); (B)
947 * msr->r_msg = msg;
948 *
949 * Where (A) orders the message value read and where (B) orders
950 * the write to the r_msg -- done in both pipelined_send and
951 * expunge_all.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952 */
Davidlohr Buesoff35e5e2015-06-30 14:58:39 -0700953 for (;;) {
954 /*
955 * Pairs with writer barrier in pipelined_send
956 * or expunge_all.
957 */
958 smp_rmb(); /* barrier (A) */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700959 msg = (struct msg_msg *)msr_d.r_msg;
Davidlohr Buesoff35e5e2015-06-30 14:58:39 -0700960 if (msg)
961 break;
962
963 /*
964 * The cpu_relax() call is a compiler barrier
965 * which forces everything in this loop to be
966 * re-loaded.
967 */
968 cpu_relax();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969 }
970
971 /* Lockless receive, part 3:
972 * If there is a message or an error then accept it without
973 * locking.
974 */
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700975 if (msg != ERR_PTR(-EAGAIN))
976 goto out_unlock1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977
978 /* Lockless receive, part 3:
979 * Acquire the queue spinlock.
980 */
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700981 ipc_lock_object(&msq->q_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982
983 /* Lockless receive, part 4:
984 * Repeat test after acquiring the spinlock.
985 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800986 msg = (struct msg_msg *)msr_d.r_msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700987 if (msg != ERR_PTR(-EAGAIN))
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700988 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989
990 list_del(&msr_d.r_list);
991 if (signal_pending(current)) {
992 msg = ERR_PTR(-ERESTARTNOHAND);
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700993 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 }
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700995
996 ipc_unlock_object(&msq->q_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 }
Davidlohr Bueso41a0d522013-07-08 16:01:18 -0700998
999out_unlock0:
1000 ipc_unlock_object(&msq->q_perm);
1001out_unlock1:
1002 rcu_read_unlock();
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -08001003 if (IS_ERR(msg)) {
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -08001004 free_copy(copy);
Ingo Molnar5a06a362006-07-30 03:04:11 -07001005 return PTR_ERR(msg);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -08001006 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -08001008 bufsz = msg_handler(buf, msg, bufsz);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 free_msg(msg);
Ingo Molnar5a06a362006-07-30 03:04:11 -07001010
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -08001011 return bufsz;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012}
1013
Heiko Carstense48fbb62009-01-14 14:14:26 +01001014SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
1015 long, msgtyp, int, msgflg)
suzuki651971c2006-12-06 20:37:48 -08001016{
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -08001017 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
suzuki651971c2006-12-06 20:37:48 -08001018}
1019
Davidlohr Bueso3440a6b2014-06-06 14:37:45 -07001020
1021void msg_init_ns(struct ipc_namespace *ns)
1022{
1023 ns->msg_ctlmax = MSGMAX;
1024 ns->msg_ctlmnb = MSGMNB;
Manfred Spraul0050ee02014-12-12 16:58:17 -08001025 ns->msg_ctlmni = MSGMNI;
Davidlohr Bueso3440a6b2014-06-06 14:37:45 -07001026
1027 atomic_set(&ns->msg_bytes, 0);
1028 atomic_set(&ns->msg_hdrs, 0);
1029 ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
1030}
1031
1032#ifdef CONFIG_IPC_NS
1033void msg_exit_ns(struct ipc_namespace *ns)
1034{
1035 free_ipcs(ns, &msg_ids(ns), freeque);
1036 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
1037}
1038#endif
1039
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -07001041static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042{
Eric W. Biederman1efdb692012-02-07 16:54:11 -08001043 struct user_namespace *user_ns = seq_user_ns(s);
Mike Waychison19b49462005-09-06 15:17:10 -07001044 struct msg_queue *msq = it;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045
Joe Perches7f032d62015-04-15 16:17:54 -07001046 seq_printf(s,
1047 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
1048 msq->q_perm.key,
1049 msq->q_perm.id,
1050 msq->q_perm.mode,
1051 msq->q_cbytes,
1052 msq->q_qnum,
1053 msq->q_lspid,
1054 msq->q_lrpid,
1055 from_kuid_munged(user_ns, msq->q_perm.uid),
1056 from_kgid_munged(user_ns, msq->q_perm.gid),
1057 from_kuid_munged(user_ns, msq->q_perm.cuid),
1058 from_kgid_munged(user_ns, msq->q_perm.cgid),
1059 msq->q_stime,
1060 msq->q_rtime,
1061 msq->q_ctime);
1062
1063 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064}
1065#endif
Davidlohr Bueso3440a6b2014-06-06 14:37:45 -07001066
1067void __init msg_init(void)
1068{
1069 msg_init_ns(&init_ipc_ns);
1070
Davidlohr Bueso3440a6b2014-06-06 14:37:45 -07001071 ipc_init_proc_interface("sysvipc/msg",
1072 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
1073 IPC_MSG_IDS, sysvipc_msg_proc_show);
1074}