ipc/msg.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/ipc/msg.c
   4  * Copyright (C) 1992 Krishna Balasubramanian
   5  *
   6  * Removed all the remaining kerneld mess
   7  * Catch the -EFAULT stuff properly
   8  * Use GFP_KERNEL for messages as in 1.2
   9  * Fixed up the unchecked user space derefs
  10  * Copyright (C) 1998 Alan Cox & Andi Kleen
  11  *
  12  * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
  13  *
  14  * mostly rewritten, threaded and wake-one semantics added
  15  * MSGMAX limit removed, sysctl's added
  16  * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
  17  *
  18  * support for audit of ipc object properties and permission changes
  19  * Dustin Kirkland <dustin.kirkland@us.ibm.com>
  20  *
  21  * namespaces support
  22  * OpenVZ, SWsoft Inc.
  23  * Pavel Emelianov <xemul@openvz.org>
  24  */
  25
  26 #include <linux/capability.h>
  27 #include <linux/msg.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/init.h>
  30 #include <linux/mm.h>
  31 #include <linux/proc_fs.h>
  32 #include <linux/list.h>
  33 #include <linux/security.h>
  34 #include <linux/sched/wake_q.h>
  35 #include <linux/syscalls.h>
  36 #include <linux/audit.h>
  37 #include <linux/seq_file.h>
  38 #include <linux/rwsem.h>
  39 #include <linux/nsproxy.h>
  40 #include <linux/ipc_namespace.h>
  41 #include <linux/rhashtable.h>
  42
  43 #include <asm/current.h>
  44 #include <linux/uaccess.h>
  45 #include "util.h"
  46
  47 /* one msq_queue structure for each present queue on the system */
  48 struct msg_queue {
  49         struct kern_ipc_perm q_perm;
  50         time64_t q_stime;               /* last msgsnd time */
  51         time64_t q_rtime;               /* last msgrcv time */
  52         time64_t q_ctime;               /* last change time */
  53         unsigned long q_cbytes;         /* current number of bytes on queue */
  54         unsigned long q_qnum;           /* number of messages in queue */
  55         unsigned long q_qbytes;         /* max number of bytes on queue */
  56         struct pid *q_lspid;            /* pid of last msgsnd */
  57         struct pid *q_lrpid;            /* last receive pid */
  58
  59         struct list_head q_messages;
  60         struct list_head q_receivers;
  61         struct list_head q_senders;
  62 } __randomize_layout;
  63
  64 /* one msg_receiver structure for each sleeping receiver */
  65 struct msg_receiver {
  66         struct list_head        r_list;
  67         struct task_struct      *r_tsk;
  68
  69         int                     r_mode;
  70         long                    r_msgtype;
  71         long                    r_maxsize;
  72
  73         struct msg_msg          *r_msg;
  74 };
  75
  76 /* one msg_sender for each sleeping sender */
  77 struct msg_sender {
  78         struct list_head        list;
  79         struct task_struct      *tsk;
  80         size_t                  msgsz;
  81 };
  82
  83 #define SEARCH_ANY              1
  84 #define SEARCH_EQUAL            2
  85 #define SEARCH_NOTEQUAL         3
  86 #define SEARCH_LESSEQUAL        4
  87 #define SEARCH_NUMBER           5
  88
  89 #define msg_ids(ns)     ((ns)->ids[IPC_MSG_IDS])
  90
  91 static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
  92 {
  93         struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&msg_ids(ns), id);
  94
  95         if (IS_ERR(ipcp))
  96                 return ERR_CAST(ipcp);
  97
  98         return container_of(ipcp, struct msg_queue, q_perm);
  99 }
 100
 101 static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
 102                                                         int id)
 103 {
 104         struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
 105
 106         if (IS_ERR(ipcp))
 107                 return ERR_CAST(ipcp);
 108
 109         return container_of(ipcp, struct msg_queue, q_perm);
 110 }
 111
 112 static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
 113 {
 114         ipc_rmid(&msg_ids(ns), &s->q_perm);
 115 }
 116
 117 static void msg_rcu_free(struct rcu_head *head)
 118 {
 119         struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
 120         struct msg_queue *msq = container_of(p, struct msg_queue, q_perm);
 121
 122         security_msg_queue_free(&msq->q_perm);
 123         kvfree(msq);
 124 }
 125
 126 /**
 127  * newque - Create a new msg queue
 128  * @ns: namespace
 129  * @params: ptr to the structure that contains the key and msgflg
 130  *
 131  * Called with msg_ids.rwsem held (writer)
 132  */
 133 static int newque(struct ipc_namespace *ns, struct ipc_params *params)
 134 {
 135         struct msg_queue *msq;
 136         int retval;
 137         key_t key = params->key;
 138         int msgflg = params->flg;
 139
 140         msq = kvmalloc(sizeof(*msq), GFP_KERNEL);
 141         if (unlikely(!msq))
 142                 return -ENOMEM;
 143
 144         msq->q_perm.mode = msgflg & S_IRWXUGO;
 145         msq->q_perm.key = key;
 146
 147         msq->q_perm.security = NULL;
 148         retval = security_msg_queue_alloc(&msq->q_perm);
 149         if (retval) {
 150                 kvfree(msq);
 151                 return retval;
 152         }
 153
 154         msq->q_stime = msq->q_rtime = 0;
 155         msq->q_ctime = ktime_get_real_seconds();
 156         msq->q_cbytes = msq->q_qnum = 0;
 157         msq->q_qbytes = ns->msg_ctlmnb;
 158         msq->q_lspid = msq->q_lrpid = NULL;
 159         INIT_LIST_HEAD(&msq->q_messages);
 160         INIT_LIST_HEAD(&msq->q_receivers);
 161         INIT_LIST_HEAD(&msq->q_senders);
 162
 163         /* ipc_addid() locks msq upon success. */
 164         retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
 165         if (retval < 0) {
 166                 call_rcu(&msq->q_perm.rcu, msg_rcu_free);
 167                 return retval;
 168         }
 169
 170         ipc_unlock_object(&msq->q_perm);
 171         rcu_read_unlock();
 172
 173         return msq->q_perm.id;
 174 }
 175
 176 static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz)
 177 {
 178         return msgsz + msq->q_cbytes <= msq->q_qbytes &&
 179                 1 + msq->q_qnum <= msq->q_qbytes;
 180 }
 181
 182 static inline void ss_add(struct msg_queue *msq,
 183                           struct msg_sender *mss, size_t msgsz)
 184 {
 185         mss->tsk = current;
 186         mss->msgsz = msgsz;
 187         __set_current_state(TASK_INTERRUPTIBLE);
 188         list_add_tail(&mss->list, &msq->q_senders);
 189 }
 190
 191 static inline void ss_del(struct msg_sender *mss)
 192 {
 193         if (mss->list.next)
 194                 list_del(&mss->list);
 195 }
 196
 197 static void ss_wakeup(struct msg_queue *msq,
 198                       struct wake_q_head *wake_q, bool kill)
 199 {
 200         struct msg_sender *mss, *t;
 201         struct task_struct *stop_tsk = NULL;
 202         struct list_head *h = &msq->q_senders;
 203
 204         list_for_each_entry_safe(mss, t, h, list) {
 205                 if (kill)
 206                         mss->list.next = NULL;
 207
 208                 /*
 209                  * Stop at the first task we don't wakeup,
 210                  * we've already iterated the original
 211                  * sender queue.
 212                  */
 213                 else if (stop_tsk == mss->tsk)
 214                         break;
 215                 /*
 216                  * We are not in an EIDRM scenario here, therefore
 217                  * verify that we really need to wakeup the task.
 218                  * To maintain current semantics and wakeup order,
 219                  * move the sender to the tail on behalf of the
 220                  * blocked task.
 221                  */
 222                 else if (!msg_fits_inqueue(msq, mss->msgsz)) {
 223                         if (!stop_tsk)
 224                                 stop_tsk = mss->tsk;
 225
 226                         list_move_tail(&mss->list, &msq->q_senders);
 227                         continue;
 228                 }
 229
 230                 wake_q_add(wake_q, mss->tsk);
 231         }
 232 }
 233
 234 static void expunge_all(struct msg_queue *msq, int res,
 235                         struct wake_q_head *wake_q)
 236 {
 237         struct msg_receiver *msr, *t;
 238
 239         list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
 240                 wake_q_add(wake_q, msr->r_tsk);
 241                 WRITE_ONCE(msr->r_msg, ERR_PTR(res));
 242         }
 243 }
 244
 245 /*
 246  * freeque() wakes up waiters on the sender and receiver waiting queue,
 247  * removes the message queue from message queue ID IDR, and cleans up all the
 248  * messages associated with this queue.
 249  *
 250  * msg_ids.rwsem (writer) and the spinlock for this message queue are held
 251  * before freeque() is called. msg_ids.rwsem remains locked on exit.
 252  */
 253 static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
 254 {
 255         struct msg_msg *msg, *t;
 256         struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
 257         DEFINE_WAKE_Q(wake_q);
 258
 259         expunge_all(msq, -EIDRM, &wake_q);
 260         ss_wakeup(msq, &wake_q, true);
 261         msg_rmid(ns, msq);
 262         ipc_unlock_object(&msq->q_perm);
 263         wake_up_q(&wake_q);
 264         rcu_read_unlock();
 265
 266         list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
 267                 atomic_dec(&ns->msg_hdrs);
 268                 free_msg(msg);
 269         }
 270         atomic_sub(msq->q_cbytes, &ns->msg_bytes);
 271         ipc_update_pid(&msq->q_lspid, NULL);
 272         ipc_update_pid(&msq->q_lrpid, NULL);
 273         ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
 274 }
 275
 276 long ksys_msgget(key_t key, int msgflg)
 277 {
 278         struct ipc_namespace *ns;
 279         static const struct ipc_ops msg_ops = {
 280                 .getnew = newque,
 281                 .associate = security_msg_queue_associate,
 282         };
 283         struct ipc_params msg_params;
 284
 285         ns = current->nsproxy->ipc_ns;
 286
 287         msg_params.key = key;
 288         msg_params.flg = msgflg;
 289
 290         return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
 291 }
 292
 293 SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
 294 {
 295         return ksys_msgget(key, msgflg);
 296 }
 297
 298 static inline unsigned long
 299 copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
 300 {
 301         switch (version) {
 302         case IPC_64:
 303                 return copy_to_user(buf, in, sizeof(*in));
 304         case IPC_OLD:
 305         {
 306                 struct msqid_ds out;
 307
 308                 memset(&out, 0, sizeof(out));
 309
 310                 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
 311
 312                 out.msg_stime           = in->msg_stime;
 313                 out.msg_rtime           = in->msg_rtime;
 314                 out.msg_ctime           = in->msg_ctime;
 315
 316                 if (in->msg_cbytes > USHRT_MAX)
 317                         out.msg_cbytes  = USHRT_MAX;
 318                 else
 319                         out.msg_cbytes  = in->msg_cbytes;
 320                 out.msg_lcbytes         = in->msg_cbytes;
 321
 322                 if (in->msg_qnum > USHRT_MAX)
 323                         out.msg_qnum    = USHRT_MAX;
 324                 else
 325                         out.msg_qnum    = in->msg_qnum;
 326
 327                 if (in->msg_qbytes > USHRT_MAX)
 328                         out.msg_qbytes  = USHRT_MAX;
 329                 else
 330                         out.msg_qbytes  = in->msg_qbytes;
 331                 out.msg_lqbytes         = in->msg_qbytes;
 332
 333                 out.msg_lspid           = in->msg_lspid;
 334                 out.msg_lrpid           = in->msg_lrpid;
 335
 336                 return copy_to_user(buf, &out, sizeof(out));
 337         }
 338         default:
 339                 return -EINVAL;
 340         }
 341 }
 342
 343 static inline unsigned long
 344 copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
 345 {
 346         switch (version) {
 347         case IPC_64:
 348                 if (copy_from_user(out, buf, sizeof(*out)))
 349                         return -EFAULT;
 350                 return 0;
 351         case IPC_OLD:
 352         {
 353                 struct msqid_ds tbuf_old;
 354
 355                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 356                         return -EFAULT;
 357
 358                 out->msg_perm.uid       = tbuf_old.msg_perm.uid;
 359                 out->msg_perm.gid       = tbuf_old.msg_perm.gid;
 360                 out->msg_perm.mode      = tbuf_old.msg_perm.mode;
 361
 362                 if (tbuf_old.msg_qbytes == 0)
 363                         out->msg_qbytes = tbuf_old.msg_lqbytes;
 364                 else
 365                         out->msg_qbytes = tbuf_old.msg_qbytes;
 366
 367                 return 0;
 368         }
 369         default:
 370                 return -EINVAL;
 371         }
 372 }
 373
 374 /*
 375  * This function handles some msgctl commands which require the rwsem
 376  * to be held in write mode.
 377  * NOTE: no locks must be held, the rwsem is taken inside this function.
 378  */
 379 static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
 380                         struct msqid64_ds *msqid64)
 381 {
 382         struct kern_ipc_perm *ipcp;
 383         struct msg_queue *msq;
 384         int err;
 385
 386         down_write(&msg_ids(ns).rwsem);
 387         rcu_read_lock();
 388
 389         ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
 390                                       &msqid64->msg_perm, msqid64->msg_qbytes);
 391         if (IS_ERR(ipcp)) {
 392                 err = PTR_ERR(ipcp);
 393                 goto out_unlock1;
 394         }
 395
 396         msq = container_of(ipcp, struct msg_queue, q_perm);
 397
 398         err = security_msg_queue_msgctl(&msq->q_perm, cmd);
 399         if (err)
 400                 goto out_unlock1;
 401
 402         switch (cmd) {
 403         case IPC_RMID:
 404                 ipc_lock_object(&msq->q_perm);
 405                 /* freeque unlocks the ipc object and rcu */
 406                 freeque(ns, ipcp);
 407                 goto out_up;
 408         case IPC_SET:
 409         {
 410                 DEFINE_WAKE_Q(wake_q);
 411
 412                 if (msqid64->msg_qbytes > ns->msg_ctlmnb &&
 413                     !capable(CAP_SYS_RESOURCE)) {
 414                         err = -EPERM;
 415                         goto out_unlock1;
 416                 }
 417
 418                 ipc_lock_object(&msq->q_perm);
 419                 err = ipc_update_perm(&msqid64->msg_perm, ipcp);
 420                 if (err)
 421                         goto out_unlock0;
 422
 423                 msq->q_qbytes = msqid64->msg_qbytes;
 424
 425                 msq->q_ctime = ktime_get_real_seconds();
 426                 /*
 427                  * Sleeping receivers might be excluded by
 428                  * stricter permissions.
 429                  */
 430                 expunge_all(msq, -EAGAIN, &wake_q);
 431                 /*
 432                  * Sleeping senders might be able to send
 433                  * due to a larger queue size.
 434                  */
 435                 ss_wakeup(msq, &wake_q, false);
 436                 ipc_unlock_object(&msq->q_perm);
 437                 wake_up_q(&wake_q);
 438
 439                 goto out_unlock1;
 440         }
 441         default:
 442                 err = -EINVAL;
 443                 goto out_unlock1;
 444         }
 445
 446 out_unlock0:
 447         ipc_unlock_object(&msq->q_perm);
 448 out_unlock1:
 449         rcu_read_unlock();
 450 out_up:
 451         up_write(&msg_ids(ns).rwsem);
 452         return err;
 453 }
 454
 455 static int msgctl_info(struct ipc_namespace *ns, int msqid,
 456                          int cmd, struct msginfo *msginfo)
 457 {
 458         int err;
 459         int max_id;
 460
 461         /*
 462          * We must not return kernel stack data.
 463          * due to padding, it's not enough
 464          * to set all member fields.
 465          */
 466         err = security_msg_queue_msgctl(NULL, cmd);
 467         if (err)
 468                 return err;
 469
 470         memset(msginfo, 0, sizeof(*msginfo));
 471         msginfo->msgmni = ns->msg_ctlmni;
 472         msginfo->msgmax = ns->msg_ctlmax;
 473         msginfo->msgmnb = ns->msg_ctlmnb;
 474         msginfo->msgssz = MSGSSZ;
 475         msginfo->msgseg = MSGSEG;
 476         down_read(&msg_ids(ns).rwsem);
 477         if (cmd == MSG_INFO) {
 478                 msginfo->msgpool = msg_ids(ns).in_use;
 479                 msginfo->msgmap = atomic_read(&ns->msg_hdrs);
 480                 msginfo->msgtql = atomic_read(&ns->msg_bytes);
 481         } else {
 482                 msginfo->msgmap = MSGMAP;
 483                 msginfo->msgpool = MSGPOOL;
 484                 msginfo->msgtql = MSGTQL;
 485         }
 486         max_id = ipc_get_maxid(&msg_ids(ns));
 487         up_read(&msg_ids(ns).rwsem);
 488         return (max_id < 0) ? 0 : max_id;
 489 }
 490
 491 static int msgctl_stat(struct ipc_namespace *ns, int msqid,
 492                          int cmd, struct msqid64_ds *p)
 493 {
 494         struct msg_queue *msq;
 495         int id = 0;
 496         int err;
 497
 498         memset(p, 0, sizeof(*p));
 499
 500         rcu_read_lock();
 501         if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) {
 502                 msq = msq_obtain_object(ns, msqid);
 503                 if (IS_ERR(msq)) {
 504                         err = PTR_ERR(msq);
 505                         goto out_unlock;
 506                 }
 507                 id = msq->q_perm.id;
 508         } else { /* IPC_STAT */
 509                 msq = msq_obtain_object_check(ns, msqid);
 510                 if (IS_ERR(msq)) {
 511                         err = PTR_ERR(msq);
 512                         goto out_unlock;
 513                 }
 514         }
 515
 516         /* see comment for SHM_STAT_ANY */
 517         if (cmd == MSG_STAT_ANY)
 518                 audit_ipc_obj(&msq->q_perm);
 519         else {
 520                 err = -EACCES;
 521                 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
 522                         goto out_unlock;
 523         }
 524
 525         err = security_msg_queue_msgctl(&msq->q_perm, cmd);
 526         if (err)
 527                 goto out_unlock;
 528
 529         ipc_lock_object(&msq->q_perm);
 530
 531         if (!ipc_valid_object(&msq->q_perm)) {
 532                 ipc_unlock_object(&msq->q_perm);
 533                 err = -EIDRM;
 534                 goto out_unlock;
 535         }
 536
 537         kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm);
 538         p->msg_stime  = msq->q_stime;
 539         p->msg_rtime  = msq->q_rtime;
 540         p->msg_ctime  = msq->q_ctime;
 541 #ifndef CONFIG_64BIT
 542         p->msg_stime_high = msq->q_stime >> 32;
 543         p->msg_rtime_high = msq->q_rtime >> 32;
 544         p->msg_ctime_high = msq->q_ctime >> 32;
 545 #endif
 546         p->msg_cbytes = msq->q_cbytes;
 547         p->msg_qnum   = msq->q_qnum;
 548         p->msg_qbytes = msq->q_qbytes;
 549         p->msg_lspid  = pid_vnr(msq->q_lspid);
 550         p->msg_lrpid  = pid_vnr(msq->q_lrpid);
 551
 552         ipc_unlock_object(&msq->q_perm);
 553         rcu_read_unlock();
 554         return id;
 555
 556 out_unlock:
 557         rcu_read_unlock();
 558         return err;
 559 }
 560
 561 long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
 562 {
 563         int version;
 564         struct ipc_namespace *ns;
 565         struct msqid64_ds msqid64;
 566         int err;
 567
 568         if (msqid < 0 || cmd < 0)
 569                 return -EINVAL;
 570
 571         version = ipc_parse_version(&cmd);
 572         ns = current->nsproxy->ipc_ns;
 573
 574         switch (cmd) {
 575         case IPC_INFO:
 576         case MSG_INFO: {
 577                 struct msginfo msginfo;
 578                 err = msgctl_info(ns, msqid, cmd, &msginfo);
 579                 if (err < 0)
 580                         return err;
 581                 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
 582                         err = -EFAULT;
 583                 return err;
 584         }
 585         case MSG_STAT:  /* msqid is an index rather than a msg queue id */
 586         case MSG_STAT_ANY:
 587         case IPC_STAT:
 588                 err = msgctl_stat(ns, msqid, cmd, &msqid64);
 589                 if (err < 0)
 590                         return err;
 591                 if (copy_msqid_to_user(buf, &msqid64, version))
 592                         err = -EFAULT;
 593                 return err;
 594         case IPC_SET:
 595                 if (copy_msqid_from_user(&msqid64, buf, version))
 596                         return -EFAULT;
 597                 /* fallthru */
 598         case IPC_RMID:
 599                 return msgctl_down(ns, msqid, cmd, &msqid64);
 600         default:
 601                 return  -EINVAL;
 602         }
 603 }
 604
 605 SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
 606 {
 607         return ksys_msgctl(msqid, cmd, buf);
 608 }
 609
 610 #ifdef CONFIG_COMPAT
 611
 612 struct compat_msqid_ds {
 613         struct compat_ipc_perm msg_perm;
 614         compat_uptr_t msg_first;
 615         compat_uptr_t msg_last;
 616         compat_time_t msg_stime;
 617         compat_time_t msg_rtime;
 618         compat_time_t msg_ctime;
 619         compat_ulong_t msg_lcbytes;
 620         compat_ulong_t msg_lqbytes;
 621         unsigned short msg_cbytes;
 622         unsigned short msg_qnum;
 623         unsigned short msg_qbytes;
 624         compat_ipc_pid_t msg_lspid;
 625         compat_ipc_pid_t msg_lrpid;
 626 };
 627
 628 static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf,
 629                                         int version)
 630 {
 631         memset(out, 0, sizeof(*out));
 632         if (version == IPC_64) {
 633                 struct compat_msqid64_ds __user *p = buf;
 634                 if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm))
 635                         return -EFAULT;
 636                 if (get_user(out->msg_qbytes, &p->msg_qbytes))
 637                         return -EFAULT;
 638         } else {
 639                 struct compat_msqid_ds __user *p = buf;
 640                 if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm))
 641                         return -EFAULT;
 642                 if (get_user(out->msg_qbytes, &p->msg_qbytes))
 643                         return -EFAULT;
 644         }
 645         return 0;
 646 }
 647
 648 static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in,
 649                                         int version)
 650 {
 651         if (version == IPC_64) {
 652                 struct compat_msqid64_ds v;
 653                 memset(&v, 0, sizeof(v));
 654                 to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm);
 655                 v.msg_stime      = lower_32_bits(in->msg_stime);
 656                 v.msg_stime_high = upper_32_bits(in->msg_stime);
 657                 v.msg_rtime      = lower_32_bits(in->msg_rtime);
 658                 v.msg_rtime_high = upper_32_bits(in->msg_rtime);
 659                 v.msg_ctime      = lower_32_bits(in->msg_ctime);
 660                 v.msg_ctime_high = upper_32_bits(in->msg_ctime);
 661                 v.msg_cbytes = in->msg_cbytes;
 662                 v.msg_qnum = in->msg_qnum;
 663                 v.msg_qbytes = in->msg_qbytes;
 664                 v.msg_lspid = in->msg_lspid;
 665                 v.msg_lrpid = in->msg_lrpid;
 666                 return copy_to_user(buf, &v, sizeof(v));
 667         } else {
 668                 struct compat_msqid_ds v;
 669                 memset(&v, 0, sizeof(v));
 670                 to_compat_ipc_perm(&v.msg_perm, &in->msg_perm);
 671                 v.msg_stime = in->msg_stime;
 672                 v.msg_rtime = in->msg_rtime;
 673                 v.msg_ctime = in->msg_ctime;
 674                 v.msg_cbytes = in->msg_cbytes;
 675                 v.msg_qnum = in->msg_qnum;
 676                 v.msg_qbytes = in->msg_qbytes;
 677                 v.msg_lspid = in->msg_lspid;
 678                 v.msg_lrpid = in->msg_lrpid;
 679                 return copy_to_user(buf, &v, sizeof(v));
 680         }
 681 }
 682
 683 long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr)
 684 {
 685         struct ipc_namespace *ns;
 686         int err;
 687         struct msqid64_ds msqid64;
 688         int version = compat_ipc_parse_version(&cmd);
 689
 690         ns = current->nsproxy->ipc_ns;
 691
 692         if (msqid < 0 || cmd < 0)
 693                 return -EINVAL;
 694
 695         switch (cmd & (~IPC_64)) {
 696         case IPC_INFO:
 697         case MSG_INFO: {
 698                 struct msginfo msginfo;
 699                 err = msgctl_info(ns, msqid, cmd, &msginfo);
 700                 if (err < 0)
 701                         return err;
 702                 if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo)))
 703                         err = -EFAULT;
 704                 return err;
 705         }
 706         case IPC_STAT:
 707         case MSG_STAT:
 708         case MSG_STAT_ANY:
 709                 err = msgctl_stat(ns, msqid, cmd, &msqid64);
 710                 if (err < 0)
 711                         return err;
 712                 if (copy_compat_msqid_to_user(uptr, &msqid64, version))
 713                         err = -EFAULT;
 714                 return err;
 715         case IPC_SET:
 716                 if (copy_compat_msqid_from_user(&msqid64, uptr, version))
 717                         return -EFAULT;
 718                 /* fallthru */
 719         case IPC_RMID:
 720                 return msgctl_down(ns, msqid, cmd, &msqid64);
 721         default:
 722                 return -EINVAL;
 723         }
 724 }
 725
 726 COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)
 727 {
 728         return compat_ksys_msgctl(msqid, cmd, uptr);
 729 }
 730 #endif
 731
 732 static int testmsg(struct msg_msg *msg, long type, int mode)
 733 {
 734         switch (mode) {
 735         case SEARCH_ANY:
 736         case SEARCH_NUMBER:
 737                 return 1;
 738         case SEARCH_LESSEQUAL:
 739                 if (msg->m_type <= type)
 740                         return 1;
 741                 break;
 742         case SEARCH_EQUAL:
 743                 if (msg->m_type == type)
 744                         return 1;
 745                 break;
 746         case SEARCH_NOTEQUAL:
 747                 if (msg->m_type != type)
 748                         return 1;
 749                 break;
 750         }
 751         return 0;
 752 }
 753
 754 static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg,
 755                                  struct wake_q_head *wake_q)
 756 {
 757         struct msg_receiver *msr, *t;
 758
 759         list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
 760                 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
 761                     !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk,
 762                                                msr->r_msgtype, msr->r_mode)) {
 763
 764                         list_del(&msr->r_list);
 765                         if (msr->r_maxsize < msg->m_ts) {
 766                                 wake_q_add(wake_q, msr->r_tsk);
 767                                 WRITE_ONCE(msr->r_msg, ERR_PTR(-E2BIG));
 768                         } else {
 769                                 ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk));
 770                                 msq->q_rtime = ktime_get_real_seconds();
 771
 772                                 wake_q_add(wake_q, msr->r_tsk);
 773                                 WRITE_ONCE(msr->r_msg, msg);
 774                                 return 1;
 775                         }
 776                 }
 777         }
 778
 779         return 0;
 780 }
 781
 782 static long do_msgsnd(int msqid, long mtype, void __user *mtext,
 783                 size_t msgsz, int msgflg)
 784 {
 785         struct msg_queue *msq;
 786         struct msg_msg *msg;
 787         int err;
 788         struct ipc_namespace *ns;
 789         DEFINE_WAKE_Q(wake_q);
 790
 791         ns = current->nsproxy->ipc_ns;
 792
 793         if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
 794                 return -EINVAL;
 795         if (mtype < 1)
 796                 return -EINVAL;
 797
 798         msg = load_msg(mtext, msgsz);
 799         if (IS_ERR(msg))
 800                 return PTR_ERR(msg);
 801
 802         msg->m_type = mtype;
 803         msg->m_ts = msgsz;
 804
 805         rcu_read_lock();
 806         msq = msq_obtain_object_check(ns, msqid);
 807         if (IS_ERR(msq)) {
 808                 err = PTR_ERR(msq);
 809                 goto out_unlock1;
 810         }
 811
 812         ipc_lock_object(&msq->q_perm);
 813
 814         for (;;) {
 815                 struct msg_sender s;
 816
 817                 err = -EACCES;
 818                 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
 819                         goto out_unlock0;
 820
 821                 /* raced with RMID? */
 822                 if (!ipc_valid_object(&msq->q_perm)) {
 823                         err = -EIDRM;
 824                         goto out_unlock0;
 825                 }
 826
 827                 err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg);
 828                 if (err)
 829                         goto out_unlock0;
 830
 831                 if (msg_fits_inqueue(msq, msgsz))
 832                         break;
 833
 834                 /* queue full, wait: */
 835                 if (msgflg & IPC_NOWAIT) {
 836                         err = -EAGAIN;
 837                         goto out_unlock0;
 838                 }
 839
 840                 /* enqueue the sender and prepare to block */
 841                 ss_add(msq, &s, msgsz);
 842
 843                 if (!ipc_rcu_getref(&msq->q_perm)) {
 844                         err = -EIDRM;
 845                         goto out_unlock0;
 846                 }
 847
 848                 ipc_unlock_object(&msq->q_perm);
 849                 rcu_read_unlock();
 850                 schedule();
 851
 852                 rcu_read_lock();
 853                 ipc_lock_object(&msq->q_perm);
 854
 855                 ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
 856                 /* raced with RMID? */
 857                 if (!ipc_valid_object(&msq->q_perm)) {
 858                         err = -EIDRM;
 859                         goto out_unlock0;
 860                 }
 861                 ss_del(&s);
 862
 863                 if (signal_pending(current)) {
 864                         err = -ERESTARTNOHAND;
 865                         goto out_unlock0;
 866                 }
 867
 868         }
 869
 870         ipc_update_pid(&msq->q_lspid, task_tgid(current));
 871         msq->q_stime = ktime_get_real_seconds();
 872
 873         if (!pipelined_send(msq, msg, &wake_q)) {
 874                 /* no one is waiting for this message, enqueue it */
 875                 list_add_tail(&msg->m_list, &msq->q_messages);
 876                 msq->q_cbytes += msgsz;
 877                 msq->q_qnum++;
 878                 atomic_add(msgsz, &ns->msg_bytes);
 879                 atomic_inc(&ns->msg_hdrs);
 880         }
 881
 882         err = 0;
 883         msg = NULL;
 884
 885 out_unlock0:
 886         ipc_unlock_object(&msq->q_perm);
 887         wake_up_q(&wake_q);
 888 out_unlock1:
 889         rcu_read_unlock();
 890         if (msg != NULL)
 891                 free_msg(msg);
 892         return err;
 893 }
 894
 895 long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
 896                  int msgflg)
 897 {
 898         long mtype;
 899
 900         if (get_user(mtype, &msgp->mtype))
 901                 return -EFAULT;
 902         return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
 903 }
 904
 905 SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
 906                 int, msgflg)
 907 {
 908         return ksys_msgsnd(msqid, msgp, msgsz, msgflg);
 909 }
 910
 911 #ifdef CONFIG_COMPAT
 912
 913 struct compat_msgbuf {
 914         compat_long_t mtype;
 915         char mtext[1];
 916 };
 917
 918 long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
 919                        compat_ssize_t msgsz, int msgflg)
 920 {
 921         struct compat_msgbuf __user *up = compat_ptr(msgp);
 922         compat_long_t mtype;
 923
 924         if (get_user(mtype, &up->mtype))
 925                 return -EFAULT;
 926         return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg);
 927 }
 928
 929 COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
 930                        compat_ssize_t, msgsz, int, msgflg)
 931 {
 932         return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg);
 933 }
 934 #endif
 935
 936 static inline int convert_mode(long *msgtyp, int msgflg)
 937 {
 938         if (msgflg & MSG_COPY)
 939                 return SEARCH_NUMBER;
 940         /*
 941          *  find message of correct type.
 942          *  msgtyp = 0 => get first.
 943          *  msgtyp > 0 => get first message of matching type.
 944          *  msgtyp < 0 => get message with least type must be < abs(msgtype).
 945          */
 946         if (*msgtyp == 0)
 947                 return SEARCH_ANY;
 948         if (*msgtyp < 0) {
 949                 if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */
 950                         *msgtyp = LONG_MAX;
 951                 else
 952                         *msgtyp = -*msgtyp;
 953                 return SEARCH_LESSEQUAL;
 954         }
 955         if (msgflg & MSG_EXCEPT)
 956                 return SEARCH_NOTEQUAL;
 957         return SEARCH_EQUAL;
 958 }
 959
 960 static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
 961 {
 962         struct msgbuf __user *msgp = dest;
 963         size_t msgsz;
 964
 965         if (put_user(msg->m_type, &msgp->mtype))
 966                 return -EFAULT;
 967
 968         msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
 969         if (store_msg(msgp->mtext, msg, msgsz))
 970                 return -EFAULT;
 971         return msgsz;
 972 }
 973
 974 #ifdef CONFIG_CHECKPOINT_RESTORE
 975 /*
 976  * This function creates new kernel message structure, large enough to store
 977  * bufsz message bytes.
 978  */
 979 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
 980 {
 981         struct msg_msg *copy;
 982
 983         /*
 984          * Create dummy message to copy real message to.
 985          */
 986         copy = load_msg(buf, bufsz);
 987         if (!IS_ERR(copy))
 988                 copy->m_ts = bufsz;
 989         return copy;
 990 }
 991
 992 static inline void free_copy(struct msg_msg *copy)
 993 {
 994         if (copy)
 995                 free_msg(copy);
 996 }
 997 #else
 998 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
 999 {
1000         return ERR_PTR(-ENOSYS);
1001 }
1002
1003 static inline void free_copy(struct msg_msg *copy)
1004 {
1005 }
1006 #endif
1007
1008 static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
1009 {
1010         struct msg_msg *msg, *found = NULL;
1011         long count = 0;
1012
1013         list_for_each_entry(msg, &msq->q_messages, m_list) {
1014                 if (testmsg(msg, *msgtyp, mode) &&
1015                     !security_msg_queue_msgrcv(&msq->q_perm, msg, current,
1016                                                *msgtyp, mode)) {
1017                         if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
1018                                 *msgtyp = msg->m_type - 1;
1019                                 found = msg;
1020                         } else if (mode == SEARCH_NUMBER) {
1021                                 if (*msgtyp == count)
1022                                         return msg;
1023                         } else
1024                                 return msg;
1025                         count++;
1026                 }
1027         }
1028
1029         return found ?: ERR_PTR(-EAGAIN);
1030 }
1031
1032 static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg,
1033                long (*msg_handler)(void __user *, struct msg_msg *, size_t))
1034 {
1035         int mode;
1036         struct msg_queue *msq;
1037         struct ipc_namespace *ns;
1038         struct msg_msg *msg, *copy = NULL;
1039         DEFINE_WAKE_Q(wake_q);
1040
1041         ns = current->nsproxy->ipc_ns;
1042
1043         if (msqid < 0 || (long) bufsz < 0)
1044                 return -EINVAL;
1045
1046         if (msgflg & MSG_COPY) {
1047                 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
1048                         return -EINVAL;
1049                 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
1050                 if (IS_ERR(copy))
1051                         return PTR_ERR(copy);
1052         }
1053         mode = convert_mode(&msgtyp, msgflg);
1054
1055         rcu_read_lock();
1056         msq = msq_obtain_object_check(ns, msqid);
1057         if (IS_ERR(msq)) {
1058                 rcu_read_unlock();
1059                 free_copy(copy);
1060                 return PTR_ERR(msq);
1061         }
1062
1063         for (;;) {
1064                 struct msg_receiver msr_d;
1065
1066                 msg = ERR_PTR(-EACCES);
1067                 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
1068                         goto out_unlock1;
1069
1070                 ipc_lock_object(&msq->q_perm);
1071
1072                 /* raced with RMID? */
1073                 if (!ipc_valid_object(&msq->q_perm)) {
1074                         msg = ERR_PTR(-EIDRM);
1075                         goto out_unlock0;
1076                 }
1077
1078                 msg = find_msg(msq, &msgtyp, mode);
1079                 if (!IS_ERR(msg)) {
1080                         /*
1081                          * Found a suitable message.
1082                          * Unlink it from the queue.
1083                          */
1084                         if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
1085                                 msg = ERR_PTR(-E2BIG);
1086                                 goto out_unlock0;
1087                         }
1088                         /*
1089                          * If we are copying, then do not unlink message and do
1090                          * not update queue parameters.
1091                          */
1092                         if (msgflg & MSG_COPY) {
1093                                 msg = copy_msg(msg, copy);
1094                                 goto out_unlock0;
1095                         }
1096
1097                         list_del(&msg->m_list);
1098                         msq->q_qnum--;
1099                         msq->q_rtime = ktime_get_real_seconds();
1100                         ipc_update_pid(&msq->q_lrpid, task_tgid(current));
1101                         msq->q_cbytes -= msg->m_ts;
1102                         atomic_sub(msg->m_ts, &ns->msg_bytes);
1103                         atomic_dec(&ns->msg_hdrs);
1104                         ss_wakeup(msq, &wake_q, false);
1105
1106                         goto out_unlock0;
1107                 }
1108
1109                 /* No message waiting. Wait for a message */
1110                 if (msgflg & IPC_NOWAIT) {
1111                         msg = ERR_PTR(-ENOMSG);
1112                         goto out_unlock0;
1113                 }
1114
1115                 list_add_tail(&msr_d.r_list, &msq->q_receivers);
1116                 msr_d.r_tsk = current;
1117                 msr_d.r_msgtype = msgtyp;
1118                 msr_d.r_mode = mode;
1119                 if (msgflg & MSG_NOERROR)
1120                         msr_d.r_maxsize = INT_MAX;
1121                 else
1122                         msr_d.r_maxsize = bufsz;
1123                 msr_d.r_msg = ERR_PTR(-EAGAIN);
1124                 __set_current_state(TASK_INTERRUPTIBLE);
1125
1126                 ipc_unlock_object(&msq->q_perm);
1127                 rcu_read_unlock();
1128                 schedule();
1129
1130                 /*
1131                  * Lockless receive, part 1:
1132                  * We don't hold a reference to the queue and getting a
1133                  * reference would defeat the idea of a lockless operation,
1134                  * thus the code relies on rcu to guarantee the existence of
1135                  * msq:
1136                  * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
1137                  * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
1138                  */
1139                 rcu_read_lock();
1140
1141                 /*
1142                  * Lockless receive, part 2:
1143                  * The work in pipelined_send() and expunge_all():
1144                  * - Set pointer to message
1145                  * - Queue the receiver task for later wakeup
1146                  * - Wake up the process after the lock is dropped.
1147                  *
1148                  * Should the process wake up before this wakeup (due to a
1149                  * signal) it will either see the message and continue ...
1150                  */
1151                 msg = READ_ONCE(msr_d.r_msg);
1152                 if (msg != ERR_PTR(-EAGAIN))
1153                         goto out_unlock1;
1154
1155                  /*
1156                   * ... or see -EAGAIN, acquire the lock to check the message
1157                   * again.
1158                   */
1159                 ipc_lock_object(&msq->q_perm);
1160
1161                 msg = msr_d.r_msg;
1162                 if (msg != ERR_PTR(-EAGAIN))
1163                         goto out_unlock0;
1164
1165                 list_del(&msr_d.r_list);
1166                 if (signal_pending(current)) {
1167                         msg = ERR_PTR(-ERESTARTNOHAND);
1168                         goto out_unlock0;
1169                 }
1170
1171                 ipc_unlock_object(&msq->q_perm);
1172         }
1173
1174 out_unlock0:
1175         ipc_unlock_object(&msq->q_perm);
1176         wake_up_q(&wake_q);
1177 out_unlock1:
1178         rcu_read_unlock();
1179         if (IS_ERR(msg)) {
1180                 free_copy(copy);
1181                 return PTR_ERR(msg);
1182         }
1183
1184         bufsz = msg_handler(buf, msg, bufsz);
1185         free_msg(msg);
1186
1187         return bufsz;
1188 }
1189
1190 long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
1191                  long msgtyp, int msgflg)
1192 {
1193         return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
1194 }
1195
1196 SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
1197                 long, msgtyp, int, msgflg)
1198 {
1199         return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1200 }
1201
1202 #ifdef CONFIG_COMPAT
1203 static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
1204 {
1205         struct compat_msgbuf __user *msgp = dest;
1206         size_t msgsz;
1207
1208         if (put_user(msg->m_type, &msgp->mtype))
1209                 return -EFAULT;
1210
1211         msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
1212         if (store_msg(msgp->mtext, msg, msgsz))
1213                 return -EFAULT;
1214         return msgsz;
1215 }
1216
1217 long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
1218                         compat_long_t msgtyp, int msgflg)
1219 {
1220         return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp,
1221                          msgflg, compat_do_msg_fill);
1222 }
1223
1224 COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
1225                        compat_ssize_t, msgsz, compat_long_t, msgtyp,
1226                        int, msgflg)
1227 {
1228         return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1229 }
1230 #endif
1231
1232 int msg_init_ns(struct ipc_namespace *ns)
1233 {
1234         ns->msg_ctlmax = MSGMAX;
1235         ns->msg_ctlmnb = MSGMNB;
1236         ns->msg_ctlmni = MSGMNI;
1237
1238         atomic_set(&ns->msg_bytes, 0);
1239         atomic_set(&ns->msg_hdrs, 0);
1240         return ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
1241 }
1242
1243 #ifdef CONFIG_IPC_NS
1244 void msg_exit_ns(struct ipc_namespace *ns)
1245 {
1246         free_ipcs(ns, &msg_ids(ns), freeque);
1247         idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
1248         rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht);
1249 }
1250 #endif
1251
1252 #ifdef CONFIG_PROC_FS
1253 static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
1254 {
1255         struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1256         struct user_namespace *user_ns = seq_user_ns(s);
1257         struct kern_ipc_perm *ipcp = it;
1258         struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
1259
1260         seq_printf(s,
1261                    "%10d %10d  %4o  %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n",
1262                    msq->q_perm.key,
1263                    msq->q_perm.id,
1264                    msq->q_perm.mode,
1265                    msq->q_cbytes,
1266                    msq->q_qnum,
1267                    pid_nr_ns(msq->q_lspid, pid_ns),
1268                    pid_nr_ns(msq->q_lrpid, pid_ns),
1269                    from_kuid_munged(user_ns, msq->q_perm.uid),
1270                    from_kgid_munged(user_ns, msq->q_perm.gid),
1271                    from_kuid_munged(user_ns, msq->q_perm.cuid),
1272                    from_kgid_munged(user_ns, msq->q_perm.cgid),
1273                    msq->q_stime,
1274                    msq->q_rtime,
1275                    msq->q_ctime);
1276
1277         return 0;
1278 }
1279 #endif
1280
1281 int __init msg_init(void)
1282 {
1283         const int err = msg_init_ns(&init_ipc_ns);
1284
1285         ipc_init_proc_interface("sysvipc/msg",
1286                                 "       key      msqid perms      cbytes       qnum lspid lrpid   uid   gid  cuid  cgid      stime      rtime      ctime\n",
1287                                 IPC_MSG_IDS, sysvipc_msg_proc_show);
1288         return err;
1289 }