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