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 #include <linux/percpu_counter.h>
  43
  44 #include <asm/current.h>
  45 #include <linux/uaccess.h>
  46 #include "util.h"
  47
  48 /* one msq_queue structure for each present queue on the system */
  49 struct msg_queue {
  50         struct kern_ipc_perm q_perm;
  51         time64_t q_stime;               /* last msgsnd time */
  52         time64_t q_rtime;               /* last msgrcv time */
  53         time64_t q_ctime;               /* last change time */
  54         unsigned long q_cbytes;         /* current number of bytes on queue */
  55         unsigned long q_qnum;           /* number of messages in queue */
  56         unsigned long q_qbytes;         /* max number of bytes on queue */
  57         struct pid *q_lspid;            /* pid of last msgsnd */
  58         struct pid *q_lrpid;            /* last receive pid */
  59
  60         struct list_head q_messages;
  61         struct list_head q_receivers;
  62         struct list_head q_senders;
  63 } __randomize_layout;
  64
  65 /*
  66  * MSG_BARRIER Locking:
  67  *
  68  * Similar to the optimization used in ipc/mqueue.c, one syscall return path
  69  * does not acquire any locks when it sees that a message exists in
  70  * msg_receiver.r_msg. Therefore r_msg is set using smp_store_release()
  71  * and accessed using READ_ONCE()+smp_acquire__after_ctrl_dep(). In addition,
  72  * wake_q_add_safe() is used. See ipc/mqueue.c for more details
  73  */
  74
  75 /* one msg_receiver structure for each sleeping receiver */
  76 struct msg_receiver {
  77         struct list_head        r_list;
  78         struct task_struct      *r_tsk;
  79
  80         int                     r_mode;
  81         long                    r_msgtype;
  82         long                    r_maxsize;
  83
  84         struct msg_msg          *r_msg;
  85 };
  86
  87 /* one msg_sender for each sleeping sender */
  88 struct msg_sender {
  89         struct list_head        list;
  90         struct task_struct      *tsk;
  91         size_t                  msgsz;
  92 };
  93
  94 #define SEARCH_ANY              1
  95 #define SEARCH_EQUAL            2
  96 #define SEARCH_NOTEQUAL         3
  97 #define SEARCH_LESSEQUAL        4
  98 #define SEARCH_NUMBER           5
  99
 100 #define msg_ids(ns)     ((ns)->ids[IPC_MSG_IDS])
 101
 102 static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
 103 {
 104         struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&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 struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
 113                                                         int id)
 114 {
 115         struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
 116
 117         if (IS_ERR(ipcp))
 118                 return ERR_CAST(ipcp);
 119
 120         return container_of(ipcp, struct msg_queue, q_perm);
 121 }
 122
 123 static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
 124 {
 125         ipc_rmid(&msg_ids(ns), &s->q_perm);
 126 }
 127
 128 static void msg_rcu_free(struct rcu_head *head)
 129 {
 130         struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
 131         struct msg_queue *msq = container_of(p, struct msg_queue, q_perm);
 132
 133         security_msg_queue_free(&msq->q_perm);
 134         kfree(msq);
 135 }
 136
 137 /**
 138  * newque - Create a new msg queue
 139  * @ns: namespace
 140  * @params: ptr to the structure that contains the key and msgflg
 141  *
 142  * Called with msg_ids.rwsem held (writer)
 143  */
 144 static int newque(struct ipc_namespace *ns, struct ipc_params *params)
 145 {
 146         struct msg_queue *msq;
 147         int retval;
 148         key_t key = params->key;
 149         int msgflg = params->flg;
 150
 151         msq = kmalloc(sizeof(*msq), GFP_KERNEL_ACCOUNT);
 152         if (unlikely(!msq))
 153                 return -ENOMEM;
 154
 155         msq->q_perm.mode = msgflg & S_IRWXUGO;
 156         msq->q_perm.key = key;
 157
 158         msq->q_perm.security = NULL;
 159         retval = security_msg_queue_alloc(&msq->q_perm);
 160         if (retval) {
 161                 kfree(msq);
 162                 return retval;
 163         }
 164
 165         msq->q_stime = msq->q_rtime = 0;
 166         msq->q_ctime = ktime_get_real_seconds();
 167         msq->q_cbytes = msq->q_qnum = 0;
 168         msq->q_qbytes = ns->msg_ctlmnb;
 169         msq->q_lspid = msq->q_lrpid = NULL;
 170         INIT_LIST_HEAD(&msq->q_messages);
 171         INIT_LIST_HEAD(&msq->q_receivers);
 172         INIT_LIST_HEAD(&msq->q_senders);
 173
 174         /* ipc_addid() locks msq upon success. */
 175         retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
 176         if (retval < 0) {
 177                 ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
 178                 return retval;
 179         }
 180
 181         ipc_unlock_object(&msq->q_perm);
 182         rcu_read_unlock();
 183
 184         return msq->q_perm.id;
 185 }
 186
 187 static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz)
 188 {
 189         return msgsz + msq->q_cbytes <= msq->q_qbytes &&
 190                 1 + msq->q_qnum <= msq->q_qbytes;
 191 }
 192
 193 static inline void ss_add(struct msg_queue *msq,
 194                           struct msg_sender *mss, size_t msgsz)
 195 {
 196         mss->tsk = current;
 197         mss->msgsz = msgsz;
 198         /*
 199          * No memory barrier required: we did ipc_lock_object(),
 200          * and the waker obtains that lock before calling wake_q_add().
 201          */
 202         __set_current_state(TASK_INTERRUPTIBLE);
 203         list_add_tail(&mss->list, &msq->q_senders);
 204 }
 205
 206 static inline void ss_del(struct msg_sender *mss)
 207 {
 208         if (mss->list.next)
 209                 list_del(&mss->list);
 210 }
 211
 212 static void ss_wakeup(struct msg_queue *msq,
 213                       struct wake_q_head *wake_q, bool kill)
 214 {
 215         struct msg_sender *mss, *t;
 216         struct task_struct *stop_tsk = NULL;
 217         struct list_head *h = &msq->q_senders;
 218
 219         list_for_each_entry_safe(mss, t, h, list) {
 220                 if (kill)
 221                         mss->list.next = NULL;
 222
 223                 /*
 224                  * Stop at the first task we don't wakeup,
 225                  * we've already iterated the original
 226                  * sender queue.
 227                  */
 228                 else if (stop_tsk == mss->tsk)
 229                         break;
 230                 /*
 231                  * We are not in an EIDRM scenario here, therefore
 232                  * verify that we really need to wakeup the task.
 233                  * To maintain current semantics and wakeup order,
 234                  * move the sender to the tail on behalf of the
 235                  * blocked task.
 236                  */
 237                 else if (!msg_fits_inqueue(msq, mss->msgsz)) {
 238                         if (!stop_tsk)
 239                                 stop_tsk = mss->tsk;
 240
 241                         list_move_tail(&mss->list, &msq->q_senders);
 242                         continue;
 243                 }
 244
 245                 wake_q_add(wake_q, mss->tsk);
 246         }
 247 }
 248
 249 static void expunge_all(struct msg_queue *msq, int res,
 250                         struct wake_q_head *wake_q)
 251 {
 252         struct msg_receiver *msr, *t;
 253
 254         list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
 255                 struct task_struct *r_tsk;
 256
 257                 r_tsk = get_task_struct(msr->r_tsk);
 258
 259                 /* see MSG_BARRIER for purpose/pairing */
 260                 smp_store_release(&msr->r_msg, ERR_PTR(res));
 261                 wake_q_add_safe(wake_q, r_tsk);
 262         }
 263 }
 264
 265 /*
 266  * freeque() wakes up waiters on the sender and receiver waiting queue,
 267  * removes the message queue from message queue ID IDR, and cleans up all the
 268  * messages associated with this queue.
 269  *
 270  * msg_ids.rwsem (writer) and the spinlock for this message queue are held
 271  * before freeque() is called. msg_ids.rwsem remains locked on exit.
 272  */
 273 static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
 274         __releases(RCU)
 275         __releases(&msq->q_perm)
 276 {
 277         struct msg_msg *msg, *t;
 278         struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
 279         DEFINE_WAKE_Q(wake_q);
 280
 281         expunge_all(msq, -EIDRM, &wake_q);
 282         ss_wakeup(msq, &wake_q, true);
 283         msg_rmid(ns, msq);
 284         ipc_unlock_object(&msq->q_perm);
 285         wake_up_q(&wake_q);
 286         rcu_read_unlock();
 287
 288         list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
 289                 percpu_counter_sub_local(&ns->percpu_msg_hdrs, 1);
 290                 free_msg(msg);
 291         }
 292         percpu_counter_sub_local(&ns->percpu_msg_bytes, msq->q_cbytes);
 293         ipc_update_pid(&msq->q_lspid, NULL);
 294         ipc_update_pid(&msq->q_lrpid, NULL);
 295         ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
 296 }
 297
 298 long ksys_msgget(key_t key, int msgflg)
 299 {
 300         struct ipc_namespace *ns;
 301         static const struct ipc_ops msg_ops = {
 302                 .getnew = newque,
 303                 .associate = security_msg_queue_associate,
 304         };
 305         struct ipc_params msg_params;
 306
 307         ns = current->nsproxy->ipc_ns;
 308
 309         msg_params.key = key;
 310         msg_params.flg = msgflg;
 311
 312         return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
 313 }
 314
 315 SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
 316 {
 317         return ksys_msgget(key, msgflg);
 318 }
 319
 320 static inline unsigned long
 321 copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
 322 {
 323         switch (version) {
 324         case IPC_64:
 325                 return copy_to_user(buf, in, sizeof(*in));
 326         case IPC_OLD:
 327         {
 328                 struct msqid_ds out;
 329
 330                 memset(&out, 0, sizeof(out));
 331
 332                 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
 333
 334                 out.msg_stime           = in->msg_stime;
 335                 out.msg_rtime           = in->msg_rtime;
 336                 out.msg_ctime           = in->msg_ctime;
 337
 338                 if (in->msg_cbytes > USHRT_MAX)
 339                         out.msg_cbytes  = USHRT_MAX;
 340                 else
 341                         out.msg_cbytes  = in->msg_cbytes;
 342                 out.msg_lcbytes         = in->msg_cbytes;
 343
 344                 if (in->msg_qnum > USHRT_MAX)
 345                         out.msg_qnum    = USHRT_MAX;
 346                 else
 347                         out.msg_qnum    = in->msg_qnum;
 348
 349                 if (in->msg_qbytes > USHRT_MAX)
 350                         out.msg_qbytes  = USHRT_MAX;
 351                 else
 352                         out.msg_qbytes  = in->msg_qbytes;
 353                 out.msg_lqbytes         = in->msg_qbytes;
 354
 355                 out.msg_lspid           = in->msg_lspid;
 356                 out.msg_lrpid           = in->msg_lrpid;
 357
 358                 return copy_to_user(buf, &out, sizeof(out));
 359         }
 360         default:
 361                 return -EINVAL;
 362         }
 363 }
 364
 365 static inline unsigned long
 366 copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
 367 {
 368         switch (version) {
 369         case IPC_64:
 370                 if (copy_from_user(out, buf, sizeof(*out)))
 371                         return -EFAULT;
 372                 return 0;
 373         case IPC_OLD:
 374         {
 375                 struct msqid_ds tbuf_old;
 376
 377                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 378                         return -EFAULT;
 379
 380                 out->msg_perm.uid       = tbuf_old.msg_perm.uid;
 381                 out->msg_perm.gid       = tbuf_old.msg_perm.gid;
 382                 out->msg_perm.mode      = tbuf_old.msg_perm.mode;
 383
 384                 if (tbuf_old.msg_qbytes == 0)
 385                         out->msg_qbytes = tbuf_old.msg_lqbytes;
 386                 else
 387                         out->msg_qbytes = tbuf_old.msg_qbytes;
 388
 389                 return 0;
 390         }
 391         default:
 392                 return -EINVAL;
 393         }
 394 }
 395
 396 /*
 397  * This function handles some msgctl commands which require the rwsem
 398  * to be held in write mode.
 399  * NOTE: no locks must be held, the rwsem is taken inside this function.
 400  */
 401 static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
 402                         struct ipc64_perm *perm, int msg_qbytes)
 403 {
 404         struct kern_ipc_perm *ipcp;
 405         struct msg_queue *msq;
 406         int err;
 407
 408         down_write(&msg_ids(ns).rwsem);
 409         rcu_read_lock();
 410
 411         ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd,
 412                                       perm, msg_qbytes);
 413         if (IS_ERR(ipcp)) {
 414                 err = PTR_ERR(ipcp);
 415                 goto out_unlock1;
 416         }
 417
 418         msq = container_of(ipcp, struct msg_queue, q_perm);
 419
 420         err = security_msg_queue_msgctl(&msq->q_perm, cmd);
 421         if (err)
 422                 goto out_unlock1;
 423
 424         switch (cmd) {
 425         case IPC_RMID:
 426                 ipc_lock_object(&msq->q_perm);
 427                 /* freeque unlocks the ipc object and rcu */
 428                 freeque(ns, ipcp);
 429                 goto out_up;
 430         case IPC_SET:
 431         {
 432                 DEFINE_WAKE_Q(wake_q);
 433
 434                 if (msg_qbytes > ns->msg_ctlmnb &&
 435                     !capable(CAP_SYS_RESOURCE)) {
 436                         err = -EPERM;
 437                         goto out_unlock1;
 438                 }
 439
 440                 ipc_lock_object(&msq->q_perm);
 441                 err = ipc_update_perm(perm, ipcp);
 442                 if (err)
 443                         goto out_unlock0;
 444
 445                 msq->q_qbytes = msg_qbytes;
 446
 447                 msq->q_ctime = ktime_get_real_seconds();
 448                 /*
 449                  * Sleeping receivers might be excluded by
 450                  * stricter permissions.
 451                  */
 452                 expunge_all(msq, -EAGAIN, &wake_q);
 453                 /*
 454                  * Sleeping senders might be able to send
 455                  * due to a larger queue size.
 456                  */
 457                 ss_wakeup(msq, &wake_q, false);
 458                 ipc_unlock_object(&msq->q_perm);
 459                 wake_up_q(&wake_q);
 460
 461                 goto out_unlock1;
 462         }
 463         default:
 464                 err = -EINVAL;
 465                 goto out_unlock1;
 466         }
 467
 468 out_unlock0:
 469         ipc_unlock_object(&msq->q_perm);
 470 out_unlock1:
 471         rcu_read_unlock();
 472 out_up:
 473         up_write(&msg_ids(ns).rwsem);
 474         return err;
 475 }
 476
 477 static int msgctl_info(struct ipc_namespace *ns, int msqid,
 478                          int cmd, struct msginfo *msginfo)
 479 {
 480         int err;
 481         int max_idx;
 482
 483         /*
 484          * We must not return kernel stack data.
 485          * due to padding, it's not enough
 486          * to set all member fields.
 487          */
 488         err = security_msg_queue_msgctl(NULL, cmd);
 489         if (err)
 490                 return err;
 491
 492         memset(msginfo, 0, sizeof(*msginfo));
 493         msginfo->msgmni = ns->msg_ctlmni;
 494         msginfo->msgmax = ns->msg_ctlmax;
 495         msginfo->msgmnb = ns->msg_ctlmnb;
 496         msginfo->msgssz = MSGSSZ;
 497         msginfo->msgseg = MSGSEG;
 498         down_read(&msg_ids(ns).rwsem);
 499         if (cmd == MSG_INFO)
 500                 msginfo->msgpool = msg_ids(ns).in_use;
 501         max_idx = ipc_get_maxidx(&msg_ids(ns));
 502         up_read(&msg_ids(ns).rwsem);
 503         if (cmd == MSG_INFO) {
 504                 msginfo->msgmap = min_t(int,
 505                                      percpu_counter_sum(&ns->percpu_msg_hdrs),
 506                                      INT_MAX);
 507                 msginfo->msgtql = min_t(int,
 508                                      percpu_counter_sum(&ns->percpu_msg_bytes),
 509                                      INT_MAX);
 510         } else {
 511                 msginfo->msgmap = MSGMAP;
 512                 msginfo->msgpool = MSGPOOL;
 513                 msginfo->msgtql = MSGTQL;
 514         }
 515         return (max_idx < 0) ? 0 : max_idx;
 516 }
 517
 518 static int msgctl_stat(struct ipc_namespace *ns, int msqid,
 519                          int cmd, struct msqid64_ds *p)
 520 {
 521         struct msg_queue *msq;
 522         int err;
 523
 524         memset(p, 0, sizeof(*p));
 525
 526         rcu_read_lock();
 527         if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) {
 528                 msq = msq_obtain_object(ns, msqid);
 529                 if (IS_ERR(msq)) {
 530                         err = PTR_ERR(msq);
 531                         goto out_unlock;
 532                 }
 533         } else { /* IPC_STAT */
 534                 msq = msq_obtain_object_check(ns, msqid);
 535                 if (IS_ERR(msq)) {
 536                         err = PTR_ERR(msq);
 537                         goto out_unlock;
 538                 }
 539         }
 540
 541         /* see comment for SHM_STAT_ANY */
 542         if (cmd == MSG_STAT_ANY)
 543                 audit_ipc_obj(&msq->q_perm);
 544         else {
 545                 err = -EACCES;
 546                 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
 547                         goto out_unlock;
 548         }
 549
 550         err = security_msg_queue_msgctl(&msq->q_perm, cmd);
 551         if (err)
 552                 goto out_unlock;
 553
 554         ipc_lock_object(&msq->q_perm);
 555
 556         if (!ipc_valid_object(&msq->q_perm)) {
 557                 ipc_unlock_object(&msq->q_perm);
 558                 err = -EIDRM;
 559                 goto out_unlock;
 560         }
 561
 562         kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm);
 563         p->msg_stime  = msq->q_stime;
 564         p->msg_rtime  = msq->q_rtime;
 565         p->msg_ctime  = msq->q_ctime;
 566 #ifndef CONFIG_64BIT
 567         p->msg_stime_high = msq->q_stime >> 32;
 568         p->msg_rtime_high = msq->q_rtime >> 32;
 569         p->msg_ctime_high = msq->q_ctime >> 32;
 570 #endif
 571         p->msg_cbytes = msq->q_cbytes;
 572         p->msg_qnum   = msq->q_qnum;
 573         p->msg_qbytes = msq->q_qbytes;
 574         p->msg_lspid  = pid_vnr(msq->q_lspid);
 575         p->msg_lrpid  = pid_vnr(msq->q_lrpid);
 576
 577         if (cmd == IPC_STAT) {
 578                 /*
 579                  * As defined in SUS:
 580                  * Return 0 on success
 581                  */
 582                 err = 0;
 583         } else {
 584                 /*
 585                  * MSG_STAT and MSG_STAT_ANY (both Linux specific)
 586                  * Return the full id, including the sequence number
 587                  */
 588                 err = msq->q_perm.id;
 589         }
 590
 591         ipc_unlock_object(&msq->q_perm);
 592 out_unlock:
 593         rcu_read_unlock();
 594         return err;
 595 }
 596
 597 static long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf, int version)
 598 {
 599         struct ipc_namespace *ns;
 600         struct msqid64_ds msqid64;
 601         int err;
 602
 603         if (msqid < 0 || cmd < 0)
 604                 return -EINVAL;
 605
 606         ns = current->nsproxy->ipc_ns;
 607
 608         switch (cmd) {
 609         case IPC_INFO:
 610         case MSG_INFO: {
 611                 struct msginfo msginfo;
 612                 err = msgctl_info(ns, msqid, cmd, &msginfo);
 613                 if (err < 0)
 614                         return err;
 615                 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
 616                         err = -EFAULT;
 617                 return err;
 618         }
 619         case MSG_STAT:  /* msqid is an index rather than a msg queue id */
 620         case MSG_STAT_ANY:
 621         case IPC_STAT:
 622                 err = msgctl_stat(ns, msqid, cmd, &msqid64);
 623                 if (err < 0)
 624                         return err;
 625                 if (copy_msqid_to_user(buf, &msqid64, version))
 626                         err = -EFAULT;
 627                 return err;
 628         case IPC_SET:
 629                 if (copy_msqid_from_user(&msqid64, buf, version))
 630                         return -EFAULT;
 631                 return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm,
 632                                    msqid64.msg_qbytes);
 633         case IPC_RMID:
 634                 return msgctl_down(ns, msqid, cmd, NULL, 0);
 635         default:
 636                 return  -EINVAL;
 637         }
 638 }
 639
 640 SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
 641 {
 642         return ksys_msgctl(msqid, cmd, buf, IPC_64);
 643 }
 644
 645 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
 646 long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
 647 {
 648         int version = ipc_parse_version(&cmd);
 649
 650         return ksys_msgctl(msqid, cmd, buf, version);
 651 }
 652
 653 SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
 654 {
 655         return ksys_old_msgctl(msqid, cmd, buf);
 656 }
 657 #endif
 658
 659 #ifdef CONFIG_COMPAT
 660
 661 struct compat_msqid_ds {
 662         struct compat_ipc_perm msg_perm;
 663         compat_uptr_t msg_first;
 664         compat_uptr_t msg_last;
 665         old_time32_t msg_stime;
 666         old_time32_t msg_rtime;
 667         old_time32_t msg_ctime;
 668         compat_ulong_t msg_lcbytes;
 669         compat_ulong_t msg_lqbytes;
 670         unsigned short msg_cbytes;
 671         unsigned short msg_qnum;
 672         unsigned short msg_qbytes;
 673         compat_ipc_pid_t msg_lspid;
 674         compat_ipc_pid_t msg_lrpid;
 675 };
 676
 677 static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf,
 678                                         int version)
 679 {
 680         memset(out, 0, sizeof(*out));
 681         if (version == IPC_64) {
 682                 struct compat_msqid64_ds __user *p = buf;
 683                 if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm))
 684                         return -EFAULT;
 685                 if (get_user(out->msg_qbytes, &p->msg_qbytes))
 686                         return -EFAULT;
 687         } else {
 688                 struct compat_msqid_ds __user *p = buf;
 689                 if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm))
 690                         return -EFAULT;
 691                 if (get_user(out->msg_qbytes, &p->msg_qbytes))
 692                         return -EFAULT;
 693         }
 694         return 0;
 695 }
 696
 697 static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in,
 698                                         int version)
 699 {
 700         if (version == IPC_64) {
 701                 struct compat_msqid64_ds v;
 702                 memset(&v, 0, sizeof(v));
 703                 to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm);
 704                 v.msg_stime      = lower_32_bits(in->msg_stime);
 705                 v.msg_stime_high = upper_32_bits(in->msg_stime);
 706                 v.msg_rtime      = lower_32_bits(in->msg_rtime);
 707                 v.msg_rtime_high = upper_32_bits(in->msg_rtime);
 708                 v.msg_ctime      = lower_32_bits(in->msg_ctime);
 709                 v.msg_ctime_high = upper_32_bits(in->msg_ctime);
 710                 v.msg_cbytes = in->msg_cbytes;
 711                 v.msg_qnum = in->msg_qnum;
 712                 v.msg_qbytes = in->msg_qbytes;
 713                 v.msg_lspid = in->msg_lspid;
 714                 v.msg_lrpid = in->msg_lrpid;
 715                 return copy_to_user(buf, &v, sizeof(v));
 716         } else {
 717                 struct compat_msqid_ds v;
 718                 memset(&v, 0, sizeof(v));
 719                 to_compat_ipc_perm(&v.msg_perm, &in->msg_perm);
 720                 v.msg_stime = in->msg_stime;
 721                 v.msg_rtime = in->msg_rtime;
 722                 v.msg_ctime = in->msg_ctime;
 723                 v.msg_cbytes = in->msg_cbytes;
 724                 v.msg_qnum = in->msg_qnum;
 725                 v.msg_qbytes = in->msg_qbytes;
 726                 v.msg_lspid = in->msg_lspid;
 727                 v.msg_lrpid = in->msg_lrpid;
 728                 return copy_to_user(buf, &v, sizeof(v));
 729         }
 730 }
 731
 732 static long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr, int version)
 733 {
 734         struct ipc_namespace *ns;
 735         int err;
 736         struct msqid64_ds msqid64;
 737
 738         ns = current->nsproxy->ipc_ns;
 739
 740         if (msqid < 0 || cmd < 0)
 741                 return -EINVAL;
 742
 743         switch (cmd & (~IPC_64)) {
 744         case IPC_INFO:
 745         case MSG_INFO: {
 746                 struct msginfo msginfo;
 747                 err = msgctl_info(ns, msqid, cmd, &msginfo);
 748                 if (err < 0)
 749                         return err;
 750                 if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo)))
 751                         err = -EFAULT;
 752                 return err;
 753         }
 754         case IPC_STAT:
 755         case MSG_STAT:
 756         case MSG_STAT_ANY:
 757                 err = msgctl_stat(ns, msqid, cmd, &msqid64);
 758                 if (err < 0)
 759                         return err;
 760                 if (copy_compat_msqid_to_user(uptr, &msqid64, version))
 761                         err = -EFAULT;
 762                 return err;
 763         case IPC_SET:
 764                 if (copy_compat_msqid_from_user(&msqid64, uptr, version))
 765                         return -EFAULT;
 766                 return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes);
 767         case IPC_RMID:
 768                 return msgctl_down(ns, msqid, cmd, NULL, 0);
 769         default:
 770                 return -EINVAL;
 771         }
 772 }
 773
 774 COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)
 775 {
 776         return compat_ksys_msgctl(msqid, cmd, uptr, IPC_64);
 777 }
 778
 779 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
 780 long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr)
 781 {
 782         int version = compat_ipc_parse_version(&cmd);
 783
 784         return compat_ksys_msgctl(msqid, cmd, uptr, version);
 785 }
 786
 787 COMPAT_SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, void __user *, uptr)
 788 {
 789         return compat_ksys_old_msgctl(msqid, cmd, uptr);
 790 }
 791 #endif
 792 #endif
 793
 794 static int testmsg(struct msg_msg *msg, long type, int mode)
 795 {
 796         switch (mode) {
 797         case SEARCH_ANY:
 798         case SEARCH_NUMBER:
 799                 return 1;
 800         case SEARCH_LESSEQUAL:
 801                 if (msg->m_type <= type)
 802                         return 1;
 803                 break;
 804         case SEARCH_EQUAL:
 805                 if (msg->m_type == type)
 806                         return 1;
 807                 break;
 808         case SEARCH_NOTEQUAL:
 809                 if (msg->m_type != type)
 810                         return 1;
 811                 break;
 812         }
 813         return 0;
 814 }
 815
 816 static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg,
 817                                  struct wake_q_head *wake_q)
 818 {
 819         struct msg_receiver *msr, *t;
 820
 821         list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
 822                 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
 823                     !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk,
 824                                                msr->r_msgtype, msr->r_mode)) {
 825
 826                         list_del(&msr->r_list);
 827                         if (msr->r_maxsize < msg->m_ts) {
 828                                 wake_q_add(wake_q, msr->r_tsk);
 829
 830                                 /* See expunge_all regarding memory barrier */
 831                                 smp_store_release(&msr->r_msg, ERR_PTR(-E2BIG));
 832                         } else {
 833                                 ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk));
 834                                 msq->q_rtime = ktime_get_real_seconds();
 835
 836                                 wake_q_add(wake_q, msr->r_tsk);
 837
 838                                 /* See expunge_all regarding memory barrier */
 839                                 smp_store_release(&msr->r_msg, msg);
 840                                 return 1;
 841                         }
 842                 }
 843         }
 844
 845         return 0;
 846 }
 847
 848 static long do_msgsnd(int msqid, long mtype, void __user *mtext,
 849                 size_t msgsz, int msgflg)
 850 {
 851         struct msg_queue *msq;
 852         struct msg_msg *msg;
 853         int err;
 854         struct ipc_namespace *ns;
 855         DEFINE_WAKE_Q(wake_q);
 856
 857         ns = current->nsproxy->ipc_ns;
 858
 859         if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
 860                 return -EINVAL;
 861         if (mtype < 1)
 862                 return -EINVAL;
 863
 864         msg = load_msg(mtext, msgsz);
 865         if (IS_ERR(msg))
 866                 return PTR_ERR(msg);
 867
 868         msg->m_type = mtype;
 869         msg->m_ts = msgsz;
 870
 871         rcu_read_lock();
 872         msq = msq_obtain_object_check(ns, msqid);
 873         if (IS_ERR(msq)) {
 874                 err = PTR_ERR(msq);
 875                 goto out_unlock1;
 876         }
 877
 878         ipc_lock_object(&msq->q_perm);
 879
 880         for (;;) {
 881                 struct msg_sender s;
 882
 883                 err = -EACCES;
 884                 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
 885                         goto out_unlock0;
 886
 887                 /* raced with RMID? */
 888                 if (!ipc_valid_object(&msq->q_perm)) {
 889                         err = -EIDRM;
 890                         goto out_unlock0;
 891                 }
 892
 893                 err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg);
 894                 if (err)
 895                         goto out_unlock0;
 896
 897                 if (msg_fits_inqueue(msq, msgsz))
 898                         break;
 899
 900                 /* queue full, wait: */
 901                 if (msgflg & IPC_NOWAIT) {
 902                         err = -EAGAIN;
 903                         goto out_unlock0;
 904                 }
 905
 906                 /* enqueue the sender and prepare to block */
 907                 ss_add(msq, &s, msgsz);
 908
 909                 if (!ipc_rcu_getref(&msq->q_perm)) {
 910                         err = -EIDRM;
 911                         goto out_unlock0;
 912                 }
 913
 914                 ipc_unlock_object(&msq->q_perm);
 915                 rcu_read_unlock();
 916                 schedule();
 917
 918                 rcu_read_lock();
 919                 ipc_lock_object(&msq->q_perm);
 920
 921                 ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
 922                 /* raced with RMID? */
 923                 if (!ipc_valid_object(&msq->q_perm)) {
 924                         err = -EIDRM;
 925                         goto out_unlock0;
 926                 }
 927                 ss_del(&s);
 928
 929                 if (signal_pending(current)) {
 930                         err = -ERESTARTNOHAND;
 931                         goto out_unlock0;
 932                 }
 933
 934         }
 935
 936         ipc_update_pid(&msq->q_lspid, task_tgid(current));
 937         msq->q_stime = ktime_get_real_seconds();
 938
 939         if (!pipelined_send(msq, msg, &wake_q)) {
 940                 /* no one is waiting for this message, enqueue it */
 941                 list_add_tail(&msg->m_list, &msq->q_messages);
 942                 msq->q_cbytes += msgsz;
 943                 msq->q_qnum++;
 944                 percpu_counter_add_local(&ns->percpu_msg_bytes, msgsz);
 945                 percpu_counter_add_local(&ns->percpu_msg_hdrs, 1);
 946         }
 947
 948         err = 0;
 949         msg = NULL;
 950
 951 out_unlock0:
 952         ipc_unlock_object(&msq->q_perm);
 953         wake_up_q(&wake_q);
 954 out_unlock1:
 955         rcu_read_unlock();
 956         if (msg != NULL)
 957                 free_msg(msg);
 958         return err;
 959 }
 960
 961 long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
 962                  int msgflg)
 963 {
 964         long mtype;
 965
 966         if (get_user(mtype, &msgp->mtype))
 967                 return -EFAULT;
 968         return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
 969 }
 970
 971 SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
 972                 int, msgflg)
 973 {
 974         return ksys_msgsnd(msqid, msgp, msgsz, msgflg);
 975 }
 976
 977 #ifdef CONFIG_COMPAT
 978
 979 struct compat_msgbuf {
 980         compat_long_t mtype;
 981         char mtext[];
 982 };
 983
 984 long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
 985                        compat_ssize_t msgsz, int msgflg)
 986 {
 987         struct compat_msgbuf __user *up = compat_ptr(msgp);
 988         compat_long_t mtype;
 989
 990         if (get_user(mtype, &up->mtype))
 991                 return -EFAULT;
 992         return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg);
 993 }
 994
 995 COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
 996                        compat_ssize_t, msgsz, int, msgflg)
 997 {
 998         return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg);
 999 }
1000 #endif
1001
1002 static inline int convert_mode(long *msgtyp, int msgflg)
1003 {
1004         if (msgflg & MSG_COPY)
1005                 return SEARCH_NUMBER;
1006         /*
1007          *  find message of correct type.
1008          *  msgtyp = 0 => get first.
1009          *  msgtyp > 0 => get first message of matching type.
1010          *  msgtyp < 0 => get message with least type must be < abs(msgtype).
1011          */
1012         if (*msgtyp == 0)
1013                 return SEARCH_ANY;
1014         if (*msgtyp < 0) {
1015                 if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */
1016                         *msgtyp = LONG_MAX;
1017                 else
1018                         *msgtyp = -*msgtyp;
1019                 return SEARCH_LESSEQUAL;
1020         }
1021         if (msgflg & MSG_EXCEPT)
1022                 return SEARCH_NOTEQUAL;
1023         return SEARCH_EQUAL;
1024 }
1025
1026 static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
1027 {
1028         struct msgbuf __user *msgp = dest;
1029         size_t msgsz;
1030
1031         if (put_user(msg->m_type, &msgp->mtype))
1032                 return -EFAULT;
1033
1034         msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
1035         if (store_msg(msgp->mtext, msg, msgsz))
1036                 return -EFAULT;
1037         return msgsz;
1038 }
1039
1040 #ifdef CONFIG_CHECKPOINT_RESTORE
1041 /*
1042  * This function creates new kernel message structure, large enough to store
1043  * bufsz message bytes.
1044  */
1045 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
1046 {
1047         struct msg_msg *copy;
1048
1049         /*
1050          * Create dummy message to copy real message to.
1051          */
1052         copy = load_msg(buf, bufsz);
1053         if (!IS_ERR(copy))
1054                 copy->m_ts = bufsz;
1055         return copy;
1056 }
1057
1058 static inline void free_copy(struct msg_msg *copy)
1059 {
1060         if (copy)
1061                 free_msg(copy);
1062 }
1063 #else
1064 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
1065 {
1066         return ERR_PTR(-ENOSYS);
1067 }
1068
1069 static inline void free_copy(struct msg_msg *copy)
1070 {
1071 }
1072 #endif
1073
1074 static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
1075 {
1076         struct msg_msg *msg, *found = NULL;
1077         long count = 0;
1078
1079         list_for_each_entry(msg, &msq->q_messages, m_list) {
1080                 if (testmsg(msg, *msgtyp, mode) &&
1081                     !security_msg_queue_msgrcv(&msq->q_perm, msg, current,
1082                                                *msgtyp, mode)) {
1083                         if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
1084                                 *msgtyp = msg->m_type - 1;
1085                                 found = msg;
1086                         } else if (mode == SEARCH_NUMBER) {
1087                                 if (*msgtyp == count)
1088                                         return msg;
1089                         } else
1090                                 return msg;
1091                         count++;
1092                 }
1093         }
1094
1095         return found ?: ERR_PTR(-EAGAIN);
1096 }
1097
1098 static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg,
1099                long (*msg_handler)(void __user *, struct msg_msg *, size_t))
1100 {
1101         int mode;
1102         struct msg_queue *msq;
1103         struct ipc_namespace *ns;
1104         struct msg_msg *msg, *copy = NULL;
1105         DEFINE_WAKE_Q(wake_q);
1106
1107         ns = current->nsproxy->ipc_ns;
1108
1109         if (msqid < 0 || (long) bufsz < 0)
1110                 return -EINVAL;
1111
1112         if (msgflg & MSG_COPY) {
1113                 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
1114                         return -EINVAL;
1115                 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
1116                 if (IS_ERR(copy))
1117                         return PTR_ERR(copy);
1118         }
1119         mode = convert_mode(&msgtyp, msgflg);
1120
1121         rcu_read_lock();
1122         msq = msq_obtain_object_check(ns, msqid);
1123         if (IS_ERR(msq)) {
1124                 rcu_read_unlock();
1125                 free_copy(copy);
1126                 return PTR_ERR(msq);
1127         }
1128
1129         for (;;) {
1130                 struct msg_receiver msr_d;
1131
1132                 msg = ERR_PTR(-EACCES);
1133                 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
1134                         goto out_unlock1;
1135
1136                 ipc_lock_object(&msq->q_perm);
1137
1138                 /* raced with RMID? */
1139                 if (!ipc_valid_object(&msq->q_perm)) {
1140                         msg = ERR_PTR(-EIDRM);
1141                         goto out_unlock0;
1142                 }
1143
1144                 msg = find_msg(msq, &msgtyp, mode);
1145                 if (!IS_ERR(msg)) {
1146                         /*
1147                          * Found a suitable message.
1148                          * Unlink it from the queue.
1149                          */
1150                         if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
1151                                 msg = ERR_PTR(-E2BIG);
1152                                 goto out_unlock0;
1153                         }
1154                         /*
1155                          * If we are copying, then do not unlink message and do
1156                          * not update queue parameters.
1157                          */
1158                         if (msgflg & MSG_COPY) {
1159                                 msg = copy_msg(msg, copy);
1160                                 goto out_unlock0;
1161                         }
1162
1163                         list_del(&msg->m_list);
1164                         msq->q_qnum--;
1165                         msq->q_rtime = ktime_get_real_seconds();
1166                         ipc_update_pid(&msq->q_lrpid, task_tgid(current));
1167                         msq->q_cbytes -= msg->m_ts;
1168                         percpu_counter_sub_local(&ns->percpu_msg_bytes, msg->m_ts);
1169                         percpu_counter_sub_local(&ns->percpu_msg_hdrs, 1);
1170                         ss_wakeup(msq, &wake_q, false);
1171
1172                         goto out_unlock0;
1173                 }
1174
1175                 /* No message waiting. Wait for a message */
1176                 if (msgflg & IPC_NOWAIT) {
1177                         msg = ERR_PTR(-ENOMSG);
1178                         goto out_unlock0;
1179                 }
1180
1181                 list_add_tail(&msr_d.r_list, &msq->q_receivers);
1182                 msr_d.r_tsk = current;
1183                 msr_d.r_msgtype = msgtyp;
1184                 msr_d.r_mode = mode;
1185                 if (msgflg & MSG_NOERROR)
1186                         msr_d.r_maxsize = INT_MAX;
1187                 else
1188                         msr_d.r_maxsize = bufsz;
1189
1190                 /* memory barrier not require due to ipc_lock_object() */
1191                 WRITE_ONCE(msr_d.r_msg, ERR_PTR(-EAGAIN));
1192
1193                 /* memory barrier not required, we own ipc_lock_object() */
1194                 __set_current_state(TASK_INTERRUPTIBLE);
1195
1196                 ipc_unlock_object(&msq->q_perm);
1197                 rcu_read_unlock();
1198                 schedule();
1199
1200                 /*
1201                  * Lockless receive, part 1:
1202                  * We don't hold a reference to the queue and getting a
1203                  * reference would defeat the idea of a lockless operation,
1204                  * thus the code relies on rcu to guarantee the existence of
1205                  * msq:
1206                  * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
1207                  * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
1208                  */
1209                 rcu_read_lock();
1210
1211                 /*
1212                  * Lockless receive, part 2:
1213                  * The work in pipelined_send() and expunge_all():
1214                  * - Set pointer to message
1215                  * - Queue the receiver task for later wakeup
1216                  * - Wake up the process after the lock is dropped.
1217                  *
1218                  * Should the process wake up before this wakeup (due to a
1219                  * signal) it will either see the message and continue ...
1220                  */
1221                 msg = READ_ONCE(msr_d.r_msg);
1222                 if (msg != ERR_PTR(-EAGAIN)) {
1223                         /* see MSG_BARRIER for purpose/pairing */
1224                         smp_acquire__after_ctrl_dep();
1225
1226                         goto out_unlock1;
1227                 }
1228
1229                  /*
1230                   * ... or see -EAGAIN, acquire the lock to check the message
1231                   * again.
1232                   */
1233                 ipc_lock_object(&msq->q_perm);
1234
1235                 msg = READ_ONCE(msr_d.r_msg);
1236                 if (msg != ERR_PTR(-EAGAIN))
1237                         goto out_unlock0;
1238
1239                 list_del(&msr_d.r_list);
1240                 if (signal_pending(current)) {
1241                         msg = ERR_PTR(-ERESTARTNOHAND);
1242                         goto out_unlock0;
1243                 }
1244
1245                 ipc_unlock_object(&msq->q_perm);
1246         }
1247
1248 out_unlock0:
1249         ipc_unlock_object(&msq->q_perm);
1250         wake_up_q(&wake_q);
1251 out_unlock1:
1252         rcu_read_unlock();
1253         if (IS_ERR(msg)) {
1254                 free_copy(copy);
1255                 return PTR_ERR(msg);
1256         }
1257
1258         bufsz = msg_handler(buf, msg, bufsz);
1259         free_msg(msg);
1260
1261         return bufsz;
1262 }
1263
1264 long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
1265                  long msgtyp, int msgflg)
1266 {
1267         return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
1268 }
1269
1270 SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
1271                 long, msgtyp, int, msgflg)
1272 {
1273         return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1274 }
1275
1276 #ifdef CONFIG_COMPAT
1277 static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
1278 {
1279         struct compat_msgbuf __user *msgp = dest;
1280         size_t msgsz;
1281
1282         if (put_user(msg->m_type, &msgp->mtype))
1283                 return -EFAULT;
1284
1285         msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
1286         if (store_msg(msgp->mtext, msg, msgsz))
1287                 return -EFAULT;
1288         return msgsz;
1289 }
1290
1291 long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
1292                         compat_long_t msgtyp, int msgflg)
1293 {
1294         return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp,
1295                          msgflg, compat_do_msg_fill);
1296 }
1297
1298 COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
1299                        compat_ssize_t, msgsz, compat_long_t, msgtyp,
1300                        int, msgflg)
1301 {
1302         return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
1303 }
1304 #endif
1305
1306 int msg_init_ns(struct ipc_namespace *ns)
1307 {
1308         int ret;
1309
1310         ns->msg_ctlmax = MSGMAX;
1311         ns->msg_ctlmnb = MSGMNB;
1312         ns->msg_ctlmni = MSGMNI;
1313
1314         ret = percpu_counter_init(&ns->percpu_msg_bytes, 0, GFP_KERNEL);
1315         if (ret)
1316                 goto fail_msg_bytes;
1317         ret = percpu_counter_init(&ns->percpu_msg_hdrs, 0, GFP_KERNEL);
1318         if (ret)
1319                 goto fail_msg_hdrs;
1320         ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
1321         return 0;
1322
1323 fail_msg_hdrs:
1324         percpu_counter_destroy(&ns->percpu_msg_bytes);
1325 fail_msg_bytes:
1326         return ret;
1327 }
1328
1329 #ifdef CONFIG_IPC_NS
1330 void msg_exit_ns(struct ipc_namespace *ns)
1331 {
1332         free_ipcs(ns, &msg_ids(ns), freeque);
1333         idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
1334         rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht);
1335         percpu_counter_destroy(&ns->percpu_msg_bytes);
1336         percpu_counter_destroy(&ns->percpu_msg_hdrs);
1337 }
1338 #endif
1339
1340 #ifdef CONFIG_PROC_FS
1341 static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
1342 {
1343         struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1344         struct user_namespace *user_ns = seq_user_ns(s);
1345         struct kern_ipc_perm *ipcp = it;
1346         struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
1347
1348         seq_printf(s,
1349                    "%10d %10d  %4o  %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n",
1350                    msq->q_perm.key,
1351                    msq->q_perm.id,
1352                    msq->q_perm.mode,
1353                    msq->q_cbytes,
1354                    msq->q_qnum,
1355                    pid_nr_ns(msq->q_lspid, pid_ns),
1356                    pid_nr_ns(msq->q_lrpid, pid_ns),
1357                    from_kuid_munged(user_ns, msq->q_perm.uid),
1358                    from_kgid_munged(user_ns, msq->q_perm.gid),
1359                    from_kuid_munged(user_ns, msq->q_perm.cuid),
1360                    from_kgid_munged(user_ns, msq->q_perm.cgid),
1361                    msq->q_stime,
1362                    msq->q_rtime,
1363                    msq->q_ctime);
1364
1365         return 0;
1366 }
1367 #endif
1368
1369 void __init msg_init(void)
1370 {
1371         msg_init_ns(&init_ipc_ns);
1372
1373         ipc_init_proc_interface("sysvipc/msg",
1374                                 "       key      msqid perms      cbytes       qnum lspid lrpid   uid   gid  cuid  cgid      stime      rtime      ctime\n",
1375                                 IPC_MSG_IDS, sysvipc_msg_proc_show);
1376 }