1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/ipc/msg.c 4 * Copyright (C) 1992 Krishna Balasubramanian 5 * 6 * Removed all the remaining kerneld mess 7 * Catch the -EFAULT stuff properly 8 * Use GFP_KERNEL for messages as in 1.2 9 * Fixed up the unchecked user space derefs 10 * Copyright (C) 1998 Alan Cox & Andi Kleen 11 * 12 * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com> 13 * 14 * mostly rewritten, threaded and wake-one semantics added 15 * MSGMAX limit removed, sysctl's added 16 * (c) 1999 Manfred Spraul <manfred@colorfullife.com> 17 * 18 * support for audit of ipc object properties and permission changes 19 * Dustin Kirkland <dustin.kirkland@us.ibm.com> 20 * 21 * namespaces support 22 * OpenVZ, SWsoft Inc. 23 * Pavel Emelianov <xemul@openvz.org> 24 */ 25 26 #include <linux/capability.h> 27 #include <linux/msg.h> 28 #include <linux/spinlock.h> 29 #include <linux/init.h> 30 #include <linux/mm.h> 31 #include <linux/proc_fs.h> 32 #include <linux/list.h> 33 #include <linux/security.h> 34 #include <linux/sched/wake_q.h> 35 #include <linux/syscalls.h> 36 #include <linux/audit.h> 37 #include <linux/seq_file.h> 38 #include <linux/rwsem.h> 39 #include <linux/nsproxy.h> 40 #include <linux/ipc_namespace.h> 41 #include <linux/rhashtable.h> 42 43 #include <asm/current.h> 44 #include <linux/uaccess.h> 45 #include "util.h" 46 47 /* one msq_queue structure for each present queue on the system */ 48 struct msg_queue { 49 struct kern_ipc_perm q_perm; 50 time64_t q_stime; /* last msgsnd time */ 51 time64_t q_rtime; /* last msgrcv time */ 52 time64_t q_ctime; /* last change time */ 53 unsigned long q_cbytes; /* current number of bytes on queue */ 54 unsigned long q_qnum; /* number of messages in queue */ 55 unsigned long q_qbytes; /* max number of bytes on queue */ 56 struct pid *q_lspid; /* pid of last msgsnd */ 57 struct pid *q_lrpid; /* last receive pid */ 58 59 struct list_head q_messages; 60 struct list_head q_receivers; 61 struct list_head q_senders; 62 } __randomize_layout; 63 64 /* 65 * MSG_BARRIER Locking: 66 * 67 * Similar to the optimization used in ipc/mqueue.c, one syscall return path 68 * does not acquire any locks when it sees that a message exists in 69 * msg_receiver.r_msg. Therefore r_msg is set using smp_store_release() 70 * and accessed using READ_ONCE()+smp_acquire__after_ctrl_dep(). In addition, 71 * wake_q_add_safe() is used. See ipc/mqueue.c for more details 72 */ 73 74 /* one msg_receiver structure for each sleeping receiver */ 75 struct msg_receiver { 76 struct list_head r_list; 77 struct task_struct *r_tsk; 78 79 int r_mode; 80 long r_msgtype; 81 long r_maxsize; 82 83 struct msg_msg *r_msg; 84 }; 85 86 /* one msg_sender for each sleeping sender */ 87 struct msg_sender { 88 struct list_head list; 89 struct task_struct *tsk; 90 size_t msgsz; 91 }; 92 93 #define SEARCH_ANY 1 94 #define SEARCH_EQUAL 2 95 #define SEARCH_NOTEQUAL 3 96 #define SEARCH_LESSEQUAL 4 97 #define SEARCH_NUMBER 5 98 99 #define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS]) 100 101 static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id) 102 { 103 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&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 struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns, 112 int id) 113 { 114 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id); 115 116 if (IS_ERR(ipcp)) 117 return ERR_CAST(ipcp); 118 119 return container_of(ipcp, struct msg_queue, q_perm); 120 } 121 122 static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s) 123 { 124 ipc_rmid(&msg_ids(ns), &s->q_perm); 125 } 126 127 static void msg_rcu_free(struct rcu_head *head) 128 { 129 struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu); 130 struct msg_queue *msq = container_of(p, struct msg_queue, q_perm); 131 132 security_msg_queue_free(&msq->q_perm); 133 kvfree(msq); 134 } 135 136 /** 137 * newque - Create a new msg queue 138 * @ns: namespace 139 * @params: ptr to the structure that contains the key and msgflg 140 * 141 * Called with msg_ids.rwsem held (writer) 142 */ 143 static int newque(struct ipc_namespace *ns, struct ipc_params *params) 144 { 145 struct msg_queue *msq; 146 int retval; 147 key_t key = params->key; 148 int msgflg = params->flg; 149 150 msq = kvmalloc(sizeof(*msq), GFP_KERNEL); 151 if (unlikely(!msq)) 152 return -ENOMEM; 153 154 msq->q_perm.mode = msgflg & S_IRWXUGO; 155 msq->q_perm.key = key; 156 157 msq->q_perm.security = NULL; 158 retval = security_msg_queue_alloc(&msq->q_perm); 159 if (retval) { 160 kvfree(msq); 161 return retval; 162 } 163 164 msq->q_stime = msq->q_rtime = 0; 165 msq->q_ctime = ktime_get_real_seconds(); 166 msq->q_cbytes = msq->q_qnum = 0; 167 msq->q_qbytes = ns->msg_ctlmnb; 168 msq->q_lspid = msq->q_lrpid = NULL; 169 INIT_LIST_HEAD(&msq->q_messages); 170 INIT_LIST_HEAD(&msq->q_receivers); 171 INIT_LIST_HEAD(&msq->q_senders); 172 173 /* ipc_addid() locks msq upon success. */ 174 retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); 175 if (retval < 0) { 176 ipc_rcu_putref(&msq->q_perm, msg_rcu_free); 177 return retval; 178 } 179 180 ipc_unlock_object(&msq->q_perm); 181 rcu_read_unlock(); 182 183 return msq->q_perm.id; 184 } 185 186 static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz) 187 { 188 return msgsz + msq->q_cbytes <= msq->q_qbytes && 189 1 + msq->q_qnum <= msq->q_qbytes; 190 } 191 192 static inline void ss_add(struct msg_queue *msq, 193 struct msg_sender *mss, size_t msgsz) 194 { 195 mss->tsk = current; 196 mss->msgsz = msgsz; 197 /* 198 * No memory barrier required: we did ipc_lock_object(), 199 * and the waker obtains that lock before calling wake_q_add(). 200 */ 201 __set_current_state(TASK_INTERRUPTIBLE); 202 list_add_tail(&mss->list, &msq->q_senders); 203 } 204 205 static inline void ss_del(struct msg_sender *mss) 206 { 207 if (mss->list.next) 208 list_del(&mss->list); 209 } 210 211 static void ss_wakeup(struct msg_queue *msq, 212 struct wake_q_head *wake_q, bool kill) 213 { 214 struct msg_sender *mss, *t; 215 struct task_struct *stop_tsk = NULL; 216 struct list_head *h = &msq->q_senders; 217 218 list_for_each_entry_safe(mss, t, h, list) { 219 if (kill) 220 mss->list.next = NULL; 221 222 /* 223 * Stop at the first task we don't wakeup, 224 * we've already iterated the original 225 * sender queue. 226 */ 227 else if (stop_tsk == mss->tsk) 228 break; 229 /* 230 * We are not in an EIDRM scenario here, therefore 231 * verify that we really need to wakeup the task. 232 * To maintain current semantics and wakeup order, 233 * move the sender to the tail on behalf of the 234 * blocked task. 235 */ 236 else if (!msg_fits_inqueue(msq, mss->msgsz)) { 237 if (!stop_tsk) 238 stop_tsk = mss->tsk; 239 240 list_move_tail(&mss->list, &msq->q_senders); 241 continue; 242 } 243 244 wake_q_add(wake_q, mss->tsk); 245 } 246 } 247 248 static void expunge_all(struct msg_queue *msq, int res, 249 struct wake_q_head *wake_q) 250 { 251 struct msg_receiver *msr, *t; 252 253 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { 254 get_task_struct(msr->r_tsk); 255 256 /* see MSG_BARRIER for purpose/pairing */ 257 smp_store_release(&msr->r_msg, ERR_PTR(res)); 258 wake_q_add_safe(wake_q, msr->r_tsk); 259 } 260 } 261 262 /* 263 * freeque() wakes up waiters on the sender and receiver waiting queue, 264 * removes the message queue from message queue ID IDR, and cleans up all the 265 * messages associated with this queue. 266 * 267 * msg_ids.rwsem (writer) and the spinlock for this message queue are held 268 * before freeque() is called. msg_ids.rwsem remains locked on exit. 269 */ 270 static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) 271 __releases(RCU) 272 __releases(&msq->q_perm) 273 { 274 struct msg_msg *msg, *t; 275 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); 276 DEFINE_WAKE_Q(wake_q); 277 278 expunge_all(msq, -EIDRM, &wake_q); 279 ss_wakeup(msq, &wake_q, true); 280 msg_rmid(ns, msq); 281 ipc_unlock_object(&msq->q_perm); 282 wake_up_q(&wake_q); 283 rcu_read_unlock(); 284 285 list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) { 286 atomic_dec(&ns->msg_hdrs); 287 free_msg(msg); 288 } 289 atomic_sub(msq->q_cbytes, &ns->msg_bytes); 290 ipc_update_pid(&msq->q_lspid, NULL); 291 ipc_update_pid(&msq->q_lrpid, NULL); 292 ipc_rcu_putref(&msq->q_perm, msg_rcu_free); 293 } 294 295 long ksys_msgget(key_t key, int msgflg) 296 { 297 struct ipc_namespace *ns; 298 static const struct ipc_ops msg_ops = { 299 .getnew = newque, 300 .associate = security_msg_queue_associate, 301 }; 302 struct ipc_params msg_params; 303 304 ns = current->nsproxy->ipc_ns; 305 306 msg_params.key = key; 307 msg_params.flg = msgflg; 308 309 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params); 310 } 311 312 SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg) 313 { 314 return ksys_msgget(key, msgflg); 315 } 316 317 static inline unsigned long 318 copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) 319 { 320 switch (version) { 321 case IPC_64: 322 return copy_to_user(buf, in, sizeof(*in)); 323 case IPC_OLD: 324 { 325 struct msqid_ds out; 326 327 memset(&out, 0, sizeof(out)); 328 329 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); 330 331 out.msg_stime = in->msg_stime; 332 out.msg_rtime = in->msg_rtime; 333 out.msg_ctime = in->msg_ctime; 334 335 if (in->msg_cbytes > USHRT_MAX) 336 out.msg_cbytes = USHRT_MAX; 337 else 338 out.msg_cbytes = in->msg_cbytes; 339 out.msg_lcbytes = in->msg_cbytes; 340 341 if (in->msg_qnum > USHRT_MAX) 342 out.msg_qnum = USHRT_MAX; 343 else 344 out.msg_qnum = in->msg_qnum; 345 346 if (in->msg_qbytes > USHRT_MAX) 347 out.msg_qbytes = USHRT_MAX; 348 else 349 out.msg_qbytes = in->msg_qbytes; 350 out.msg_lqbytes = in->msg_qbytes; 351 352 out.msg_lspid = in->msg_lspid; 353 out.msg_lrpid = in->msg_lrpid; 354 355 return copy_to_user(buf, &out, sizeof(out)); 356 } 357 default: 358 return -EINVAL; 359 } 360 } 361 362 static inline unsigned long 363 copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version) 364 { 365 switch (version) { 366 case IPC_64: 367 if (copy_from_user(out, buf, sizeof(*out))) 368 return -EFAULT; 369 return 0; 370 case IPC_OLD: 371 { 372 struct msqid_ds tbuf_old; 373 374 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) 375 return -EFAULT; 376 377 out->msg_perm.uid = tbuf_old.msg_perm.uid; 378 out->msg_perm.gid = tbuf_old.msg_perm.gid; 379 out->msg_perm.mode = tbuf_old.msg_perm.mode; 380 381 if (tbuf_old.msg_qbytes == 0) 382 out->msg_qbytes = tbuf_old.msg_lqbytes; 383 else 384 out->msg_qbytes = tbuf_old.msg_qbytes; 385 386 return 0; 387 } 388 default: 389 return -EINVAL; 390 } 391 } 392 393 /* 394 * This function handles some msgctl commands which require the rwsem 395 * to be held in write mode. 396 * NOTE: no locks must be held, the rwsem is taken inside this function. 397 */ 398 static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, 399 struct ipc64_perm *perm, int msg_qbytes) 400 { 401 struct kern_ipc_perm *ipcp; 402 struct msg_queue *msq; 403 int err; 404 405 down_write(&msg_ids(ns).rwsem); 406 rcu_read_lock(); 407 408 ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd, 409 perm, msg_qbytes); 410 if (IS_ERR(ipcp)) { 411 err = PTR_ERR(ipcp); 412 goto out_unlock1; 413 } 414 415 msq = container_of(ipcp, struct msg_queue, q_perm); 416 417 err = security_msg_queue_msgctl(&msq->q_perm, cmd); 418 if (err) 419 goto out_unlock1; 420 421 switch (cmd) { 422 case IPC_RMID: 423 ipc_lock_object(&msq->q_perm); 424 /* freeque unlocks the ipc object and rcu */ 425 freeque(ns, ipcp); 426 goto out_up; 427 case IPC_SET: 428 { 429 DEFINE_WAKE_Q(wake_q); 430 431 if (msg_qbytes > ns->msg_ctlmnb && 432 !capable(CAP_SYS_RESOURCE)) { 433 err = -EPERM; 434 goto out_unlock1; 435 } 436 437 ipc_lock_object(&msq->q_perm); 438 err = ipc_update_perm(perm, ipcp); 439 if (err) 440 goto out_unlock0; 441 442 msq->q_qbytes = msg_qbytes; 443 444 msq->q_ctime = ktime_get_real_seconds(); 445 /* 446 * Sleeping receivers might be excluded by 447 * stricter permissions. 448 */ 449 expunge_all(msq, -EAGAIN, &wake_q); 450 /* 451 * Sleeping senders might be able to send 452 * due to a larger queue size. 453 */ 454 ss_wakeup(msq, &wake_q, false); 455 ipc_unlock_object(&msq->q_perm); 456 wake_up_q(&wake_q); 457 458 goto out_unlock1; 459 } 460 default: 461 err = -EINVAL; 462 goto out_unlock1; 463 } 464 465 out_unlock0: 466 ipc_unlock_object(&msq->q_perm); 467 out_unlock1: 468 rcu_read_unlock(); 469 out_up: 470 up_write(&msg_ids(ns).rwsem); 471 return err; 472 } 473 474 static int msgctl_info(struct ipc_namespace *ns, int msqid, 475 int cmd, struct msginfo *msginfo) 476 { 477 int err; 478 int max_idx; 479 480 /* 481 * We must not return kernel stack data. 482 * due to padding, it's not enough 483 * to set all member fields. 484 */ 485 err = security_msg_queue_msgctl(NULL, cmd); 486 if (err) 487 return err; 488 489 memset(msginfo, 0, sizeof(*msginfo)); 490 msginfo->msgmni = ns->msg_ctlmni; 491 msginfo->msgmax = ns->msg_ctlmax; 492 msginfo->msgmnb = ns->msg_ctlmnb; 493 msginfo->msgssz = MSGSSZ; 494 msginfo->msgseg = MSGSEG; 495 down_read(&msg_ids(ns).rwsem); 496 if (cmd == MSG_INFO) { 497 msginfo->msgpool = msg_ids(ns).in_use; 498 msginfo->msgmap = atomic_read(&ns->msg_hdrs); 499 msginfo->msgtql = atomic_read(&ns->msg_bytes); 500 } else { 501 msginfo->msgmap = MSGMAP; 502 msginfo->msgpool = MSGPOOL; 503 msginfo->msgtql = MSGTQL; 504 } 505 max_idx = ipc_get_maxidx(&msg_ids(ns)); 506 up_read(&msg_ids(ns).rwsem); 507 return (max_idx < 0) ? 0 : max_idx; 508 } 509 510 static int msgctl_stat(struct ipc_namespace *ns, int msqid, 511 int cmd, struct msqid64_ds *p) 512 { 513 struct msg_queue *msq; 514 int err; 515 516 memset(p, 0, sizeof(*p)); 517 518 rcu_read_lock(); 519 if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) { 520 msq = msq_obtain_object(ns, msqid); 521 if (IS_ERR(msq)) { 522 err = PTR_ERR(msq); 523 goto out_unlock; 524 } 525 } else { /* IPC_STAT */ 526 msq = msq_obtain_object_check(ns, msqid); 527 if (IS_ERR(msq)) { 528 err = PTR_ERR(msq); 529 goto out_unlock; 530 } 531 } 532 533 /* see comment for SHM_STAT_ANY */ 534 if (cmd == MSG_STAT_ANY) 535 audit_ipc_obj(&msq->q_perm); 536 else { 537 err = -EACCES; 538 if (ipcperms(ns, &msq->q_perm, S_IRUGO)) 539 goto out_unlock; 540 } 541 542 err = security_msg_queue_msgctl(&msq->q_perm, cmd); 543 if (err) 544 goto out_unlock; 545 546 ipc_lock_object(&msq->q_perm); 547 548 if (!ipc_valid_object(&msq->q_perm)) { 549 ipc_unlock_object(&msq->q_perm); 550 err = -EIDRM; 551 goto out_unlock; 552 } 553 554 kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm); 555 p->msg_stime = msq->q_stime; 556 p->msg_rtime = msq->q_rtime; 557 p->msg_ctime = msq->q_ctime; 558 #ifndef CONFIG_64BIT 559 p->msg_stime_high = msq->q_stime >> 32; 560 p->msg_rtime_high = msq->q_rtime >> 32; 561 p->msg_ctime_high = msq->q_ctime >> 32; 562 #endif 563 p->msg_cbytes = msq->q_cbytes; 564 p->msg_qnum = msq->q_qnum; 565 p->msg_qbytes = msq->q_qbytes; 566 p->msg_lspid = pid_vnr(msq->q_lspid); 567 p->msg_lrpid = pid_vnr(msq->q_lrpid); 568 569 if (cmd == IPC_STAT) { 570 /* 571 * As defined in SUS: 572 * Return 0 on success 573 */ 574 err = 0; 575 } else { 576 /* 577 * MSG_STAT and MSG_STAT_ANY (both Linux specific) 578 * Return the full id, including the sequence number 579 */ 580 err = msq->q_perm.id; 581 } 582 583 ipc_unlock_object(&msq->q_perm); 584 out_unlock: 585 rcu_read_unlock(); 586 return err; 587 } 588 589 static long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf, int version) 590 { 591 struct ipc_namespace *ns; 592 struct msqid64_ds msqid64; 593 int err; 594 595 if (msqid < 0 || cmd < 0) 596 return -EINVAL; 597 598 ns = current->nsproxy->ipc_ns; 599 600 switch (cmd) { 601 case IPC_INFO: 602 case MSG_INFO: { 603 struct msginfo msginfo; 604 err = msgctl_info(ns, msqid, cmd, &msginfo); 605 if (err < 0) 606 return err; 607 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) 608 err = -EFAULT; 609 return err; 610 } 611 case MSG_STAT: /* msqid is an index rather than a msg queue id */ 612 case MSG_STAT_ANY: 613 case IPC_STAT: 614 err = msgctl_stat(ns, msqid, cmd, &msqid64); 615 if (err < 0) 616 return err; 617 if (copy_msqid_to_user(buf, &msqid64, version)) 618 err = -EFAULT; 619 return err; 620 case IPC_SET: 621 if (copy_msqid_from_user(&msqid64, buf, version)) 622 return -EFAULT; 623 return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, 624 msqid64.msg_qbytes); 625 case IPC_RMID: 626 return msgctl_down(ns, msqid, cmd, NULL, 0); 627 default: 628 return -EINVAL; 629 } 630 } 631 632 SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) 633 { 634 return ksys_msgctl(msqid, cmd, buf, IPC_64); 635 } 636 637 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION 638 long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) 639 { 640 int version = ipc_parse_version(&cmd); 641 642 return ksys_msgctl(msqid, cmd, buf, version); 643 } 644 645 SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) 646 { 647 return ksys_old_msgctl(msqid, cmd, buf); 648 } 649 #endif 650 651 #ifdef CONFIG_COMPAT 652 653 struct compat_msqid_ds { 654 struct compat_ipc_perm msg_perm; 655 compat_uptr_t msg_first; 656 compat_uptr_t msg_last; 657 old_time32_t msg_stime; 658 old_time32_t msg_rtime; 659 old_time32_t msg_ctime; 660 compat_ulong_t msg_lcbytes; 661 compat_ulong_t msg_lqbytes; 662 unsigned short msg_cbytes; 663 unsigned short msg_qnum; 664 unsigned short msg_qbytes; 665 compat_ipc_pid_t msg_lspid; 666 compat_ipc_pid_t msg_lrpid; 667 }; 668 669 static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf, 670 int version) 671 { 672 memset(out, 0, sizeof(*out)); 673 if (version == IPC_64) { 674 struct compat_msqid64_ds __user *p = buf; 675 if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm)) 676 return -EFAULT; 677 if (get_user(out->msg_qbytes, &p->msg_qbytes)) 678 return -EFAULT; 679 } else { 680 struct compat_msqid_ds __user *p = buf; 681 if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm)) 682 return -EFAULT; 683 if (get_user(out->msg_qbytes, &p->msg_qbytes)) 684 return -EFAULT; 685 } 686 return 0; 687 } 688 689 static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in, 690 int version) 691 { 692 if (version == IPC_64) { 693 struct compat_msqid64_ds v; 694 memset(&v, 0, sizeof(v)); 695 to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm); 696 v.msg_stime = lower_32_bits(in->msg_stime); 697 v.msg_stime_high = upper_32_bits(in->msg_stime); 698 v.msg_rtime = lower_32_bits(in->msg_rtime); 699 v.msg_rtime_high = upper_32_bits(in->msg_rtime); 700 v.msg_ctime = lower_32_bits(in->msg_ctime); 701 v.msg_ctime_high = upper_32_bits(in->msg_ctime); 702 v.msg_cbytes = in->msg_cbytes; 703 v.msg_qnum = in->msg_qnum; 704 v.msg_qbytes = in->msg_qbytes; 705 v.msg_lspid = in->msg_lspid; 706 v.msg_lrpid = in->msg_lrpid; 707 return copy_to_user(buf, &v, sizeof(v)); 708 } else { 709 struct compat_msqid_ds v; 710 memset(&v, 0, sizeof(v)); 711 to_compat_ipc_perm(&v.msg_perm, &in->msg_perm); 712 v.msg_stime = in->msg_stime; 713 v.msg_rtime = in->msg_rtime; 714 v.msg_ctime = in->msg_ctime; 715 v.msg_cbytes = in->msg_cbytes; 716 v.msg_qnum = in->msg_qnum; 717 v.msg_qbytes = in->msg_qbytes; 718 v.msg_lspid = in->msg_lspid; 719 v.msg_lrpid = in->msg_lrpid; 720 return copy_to_user(buf, &v, sizeof(v)); 721 } 722 } 723 724 static long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr, int version) 725 { 726 struct ipc_namespace *ns; 727 int err; 728 struct msqid64_ds msqid64; 729 730 ns = current->nsproxy->ipc_ns; 731 732 if (msqid < 0 || cmd < 0) 733 return -EINVAL; 734 735 switch (cmd & (~IPC_64)) { 736 case IPC_INFO: 737 case MSG_INFO: { 738 struct msginfo msginfo; 739 err = msgctl_info(ns, msqid, cmd, &msginfo); 740 if (err < 0) 741 return err; 742 if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo))) 743 err = -EFAULT; 744 return err; 745 } 746 case IPC_STAT: 747 case MSG_STAT: 748 case MSG_STAT_ANY: 749 err = msgctl_stat(ns, msqid, cmd, &msqid64); 750 if (err < 0) 751 return err; 752 if (copy_compat_msqid_to_user(uptr, &msqid64, version)) 753 err = -EFAULT; 754 return err; 755 case IPC_SET: 756 if (copy_compat_msqid_from_user(&msqid64, uptr, version)) 757 return -EFAULT; 758 return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes); 759 case IPC_RMID: 760 return msgctl_down(ns, msqid, cmd, NULL, 0); 761 default: 762 return -EINVAL; 763 } 764 } 765 766 COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr) 767 { 768 return compat_ksys_msgctl(msqid, cmd, uptr, IPC_64); 769 } 770 771 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION 772 long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr) 773 { 774 int version = compat_ipc_parse_version(&cmd); 775 776 return compat_ksys_msgctl(msqid, cmd, uptr, version); 777 } 778 779 COMPAT_SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, void __user *, uptr) 780 { 781 return compat_ksys_old_msgctl(msqid, cmd, uptr); 782 } 783 #endif 784 #endif 785 786 static int testmsg(struct msg_msg *msg, long type, int mode) 787 { 788 switch (mode) { 789 case SEARCH_ANY: 790 case SEARCH_NUMBER: 791 return 1; 792 case SEARCH_LESSEQUAL: 793 if (msg->m_type <= type) 794 return 1; 795 break; 796 case SEARCH_EQUAL: 797 if (msg->m_type == type) 798 return 1; 799 break; 800 case SEARCH_NOTEQUAL: 801 if (msg->m_type != type) 802 return 1; 803 break; 804 } 805 return 0; 806 } 807 808 static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg, 809 struct wake_q_head *wake_q) 810 { 811 struct msg_receiver *msr, *t; 812 813 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { 814 if (testmsg(msg, msr->r_msgtype, msr->r_mode) && 815 !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk, 816 msr->r_msgtype, msr->r_mode)) { 817 818 list_del(&msr->r_list); 819 if (msr->r_maxsize < msg->m_ts) { 820 wake_q_add(wake_q, msr->r_tsk); 821 822 /* See expunge_all regarding memory barrier */ 823 smp_store_release(&msr->r_msg, ERR_PTR(-E2BIG)); 824 } else { 825 ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk)); 826 msq->q_rtime = ktime_get_real_seconds(); 827 828 wake_q_add(wake_q, msr->r_tsk); 829 830 /* See expunge_all regarding memory barrier */ 831 smp_store_release(&msr->r_msg, msg); 832 return 1; 833 } 834 } 835 } 836 837 return 0; 838 } 839 840 static long do_msgsnd(int msqid, long mtype, void __user *mtext, 841 size_t msgsz, int msgflg) 842 { 843 struct msg_queue *msq; 844 struct msg_msg *msg; 845 int err; 846 struct ipc_namespace *ns; 847 DEFINE_WAKE_Q(wake_q); 848 849 ns = current->nsproxy->ipc_ns; 850 851 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0) 852 return -EINVAL; 853 if (mtype < 1) 854 return -EINVAL; 855 856 msg = load_msg(mtext, msgsz); 857 if (IS_ERR(msg)) 858 return PTR_ERR(msg); 859 860 msg->m_type = mtype; 861 msg->m_ts = msgsz; 862 863 rcu_read_lock(); 864 msq = msq_obtain_object_check(ns, msqid); 865 if (IS_ERR(msq)) { 866 err = PTR_ERR(msq); 867 goto out_unlock1; 868 } 869 870 ipc_lock_object(&msq->q_perm); 871 872 for (;;) { 873 struct msg_sender s; 874 875 err = -EACCES; 876 if (ipcperms(ns, &msq->q_perm, S_IWUGO)) 877 goto out_unlock0; 878 879 /* raced with RMID? */ 880 if (!ipc_valid_object(&msq->q_perm)) { 881 err = -EIDRM; 882 goto out_unlock0; 883 } 884 885 err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg); 886 if (err) 887 goto out_unlock0; 888 889 if (msg_fits_inqueue(msq, msgsz)) 890 break; 891 892 /* queue full, wait: */ 893 if (msgflg & IPC_NOWAIT) { 894 err = -EAGAIN; 895 goto out_unlock0; 896 } 897 898 /* enqueue the sender and prepare to block */ 899 ss_add(msq, &s, msgsz); 900 901 if (!ipc_rcu_getref(&msq->q_perm)) { 902 err = -EIDRM; 903 goto out_unlock0; 904 } 905 906 ipc_unlock_object(&msq->q_perm); 907 rcu_read_unlock(); 908 schedule(); 909 910 rcu_read_lock(); 911 ipc_lock_object(&msq->q_perm); 912 913 ipc_rcu_putref(&msq->q_perm, msg_rcu_free); 914 /* raced with RMID? */ 915 if (!ipc_valid_object(&msq->q_perm)) { 916 err = -EIDRM; 917 goto out_unlock0; 918 } 919 ss_del(&s); 920 921 if (signal_pending(current)) { 922 err = -ERESTARTNOHAND; 923 goto out_unlock0; 924 } 925 926 } 927 928 ipc_update_pid(&msq->q_lspid, task_tgid(current)); 929 msq->q_stime = ktime_get_real_seconds(); 930 931 if (!pipelined_send(msq, msg, &wake_q)) { 932 /* no one is waiting for this message, enqueue it */ 933 list_add_tail(&msg->m_list, &msq->q_messages); 934 msq->q_cbytes += msgsz; 935 msq->q_qnum++; 936 atomic_add(msgsz, &ns->msg_bytes); 937 atomic_inc(&ns->msg_hdrs); 938 } 939 940 err = 0; 941 msg = NULL; 942 943 out_unlock0: 944 ipc_unlock_object(&msq->q_perm); 945 wake_up_q(&wake_q); 946 out_unlock1: 947 rcu_read_unlock(); 948 if (msg != NULL) 949 free_msg(msg); 950 return err; 951 } 952 953 long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, 954 int msgflg) 955 { 956 long mtype; 957 958 if (get_user(mtype, &msgp->mtype)) 959 return -EFAULT; 960 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg); 961 } 962 963 SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, 964 int, msgflg) 965 { 966 return ksys_msgsnd(msqid, msgp, msgsz, msgflg); 967 } 968 969 #ifdef CONFIG_COMPAT 970 971 struct compat_msgbuf { 972 compat_long_t mtype; 973 char mtext[1]; 974 }; 975 976 long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp, 977 compat_ssize_t msgsz, int msgflg) 978 { 979 struct compat_msgbuf __user *up = compat_ptr(msgp); 980 compat_long_t mtype; 981 982 if (get_user(mtype, &up->mtype)) 983 return -EFAULT; 984 return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg); 985 } 986 987 COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp, 988 compat_ssize_t, msgsz, int, msgflg) 989 { 990 return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg); 991 } 992 #endif 993 994 static inline int convert_mode(long *msgtyp, int msgflg) 995 { 996 if (msgflg & MSG_COPY) 997 return SEARCH_NUMBER; 998 /* 999 * find message of correct type. 1000 * msgtyp = 0 => get first. 1001 * msgtyp > 0 => get first message of matching type. 1002 * msgtyp < 0 => get message with least type must be < abs(msgtype). 1003 */ 1004 if (*msgtyp == 0) 1005 return SEARCH_ANY; 1006 if (*msgtyp < 0) { 1007 if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */ 1008 *msgtyp = LONG_MAX; 1009 else 1010 *msgtyp = -*msgtyp; 1011 return SEARCH_LESSEQUAL; 1012 } 1013 if (msgflg & MSG_EXCEPT) 1014 return SEARCH_NOTEQUAL; 1015 return SEARCH_EQUAL; 1016 } 1017 1018 static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) 1019 { 1020 struct msgbuf __user *msgp = dest; 1021 size_t msgsz; 1022 1023 if (put_user(msg->m_type, &msgp->mtype)) 1024 return -EFAULT; 1025 1026 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; 1027 if (store_msg(msgp->mtext, msg, msgsz)) 1028 return -EFAULT; 1029 return msgsz; 1030 } 1031 1032 #ifdef CONFIG_CHECKPOINT_RESTORE 1033 /* 1034 * This function creates new kernel message structure, large enough to store 1035 * bufsz message bytes. 1036 */ 1037 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) 1038 { 1039 struct msg_msg *copy; 1040 1041 /* 1042 * Create dummy message to copy real message to. 1043 */ 1044 copy = load_msg(buf, bufsz); 1045 if (!IS_ERR(copy)) 1046 copy->m_ts = bufsz; 1047 return copy; 1048 } 1049 1050 static inline void free_copy(struct msg_msg *copy) 1051 { 1052 if (copy) 1053 free_msg(copy); 1054 } 1055 #else 1056 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) 1057 { 1058 return ERR_PTR(-ENOSYS); 1059 } 1060 1061 static inline void free_copy(struct msg_msg *copy) 1062 { 1063 } 1064 #endif 1065 1066 static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode) 1067 { 1068 struct msg_msg *msg, *found = NULL; 1069 long count = 0; 1070 1071 list_for_each_entry(msg, &msq->q_messages, m_list) { 1072 if (testmsg(msg, *msgtyp, mode) && 1073 !security_msg_queue_msgrcv(&msq->q_perm, msg, current, 1074 *msgtyp, mode)) { 1075 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) { 1076 *msgtyp = msg->m_type - 1; 1077 found = msg; 1078 } else if (mode == SEARCH_NUMBER) { 1079 if (*msgtyp == count) 1080 return msg; 1081 } else 1082 return msg; 1083 count++; 1084 } 1085 } 1086 1087 return found ?: ERR_PTR(-EAGAIN); 1088 } 1089 1090 static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg, 1091 long (*msg_handler)(void __user *, struct msg_msg *, size_t)) 1092 { 1093 int mode; 1094 struct msg_queue *msq; 1095 struct ipc_namespace *ns; 1096 struct msg_msg *msg, *copy = NULL; 1097 DEFINE_WAKE_Q(wake_q); 1098 1099 ns = current->nsproxy->ipc_ns; 1100 1101 if (msqid < 0 || (long) bufsz < 0) 1102 return -EINVAL; 1103 1104 if (msgflg & MSG_COPY) { 1105 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT)) 1106 return -EINVAL; 1107 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); 1108 if (IS_ERR(copy)) 1109 return PTR_ERR(copy); 1110 } 1111 mode = convert_mode(&msgtyp, msgflg); 1112 1113 rcu_read_lock(); 1114 msq = msq_obtain_object_check(ns, msqid); 1115 if (IS_ERR(msq)) { 1116 rcu_read_unlock(); 1117 free_copy(copy); 1118 return PTR_ERR(msq); 1119 } 1120 1121 for (;;) { 1122 struct msg_receiver msr_d; 1123 1124 msg = ERR_PTR(-EACCES); 1125 if (ipcperms(ns, &msq->q_perm, S_IRUGO)) 1126 goto out_unlock1; 1127 1128 ipc_lock_object(&msq->q_perm); 1129 1130 /* raced with RMID? */ 1131 if (!ipc_valid_object(&msq->q_perm)) { 1132 msg = ERR_PTR(-EIDRM); 1133 goto out_unlock0; 1134 } 1135 1136 msg = find_msg(msq, &msgtyp, mode); 1137 if (!IS_ERR(msg)) { 1138 /* 1139 * Found a suitable message. 1140 * Unlink it from the queue. 1141 */ 1142 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { 1143 msg = ERR_PTR(-E2BIG); 1144 goto out_unlock0; 1145 } 1146 /* 1147 * If we are copying, then do not unlink message and do 1148 * not update queue parameters. 1149 */ 1150 if (msgflg & MSG_COPY) { 1151 msg = copy_msg(msg, copy); 1152 goto out_unlock0; 1153 } 1154 1155 list_del(&msg->m_list); 1156 msq->q_qnum--; 1157 msq->q_rtime = ktime_get_real_seconds(); 1158 ipc_update_pid(&msq->q_lrpid, task_tgid(current)); 1159 msq->q_cbytes -= msg->m_ts; 1160 atomic_sub(msg->m_ts, &ns->msg_bytes); 1161 atomic_dec(&ns->msg_hdrs); 1162 ss_wakeup(msq, &wake_q, false); 1163 1164 goto out_unlock0; 1165 } 1166 1167 /* No message waiting. Wait for a message */ 1168 if (msgflg & IPC_NOWAIT) { 1169 msg = ERR_PTR(-ENOMSG); 1170 goto out_unlock0; 1171 } 1172 1173 list_add_tail(&msr_d.r_list, &msq->q_receivers); 1174 msr_d.r_tsk = current; 1175 msr_d.r_msgtype = msgtyp; 1176 msr_d.r_mode = mode; 1177 if (msgflg & MSG_NOERROR) 1178 msr_d.r_maxsize = INT_MAX; 1179 else 1180 msr_d.r_maxsize = bufsz; 1181 1182 /* memory barrier not require due to ipc_lock_object() */ 1183 WRITE_ONCE(msr_d.r_msg, ERR_PTR(-EAGAIN)); 1184 1185 /* memory barrier not required, we own ipc_lock_object() */ 1186 __set_current_state(TASK_INTERRUPTIBLE); 1187 1188 ipc_unlock_object(&msq->q_perm); 1189 rcu_read_unlock(); 1190 schedule(); 1191 1192 /* 1193 * Lockless receive, part 1: 1194 * We don't hold a reference to the queue and getting a 1195 * reference would defeat the idea of a lockless operation, 1196 * thus the code relies on rcu to guarantee the existence of 1197 * msq: 1198 * Prior to destruction, expunge_all(-EIRDM) changes r_msg. 1199 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. 1200 */ 1201 rcu_read_lock(); 1202 1203 /* 1204 * Lockless receive, part 2: 1205 * The work in pipelined_send() and expunge_all(): 1206 * - Set pointer to message 1207 * - Queue the receiver task for later wakeup 1208 * - Wake up the process after the lock is dropped. 1209 * 1210 * Should the process wake up before this wakeup (due to a 1211 * signal) it will either see the message and continue ... 1212 */ 1213 msg = READ_ONCE(msr_d.r_msg); 1214 if (msg != ERR_PTR(-EAGAIN)) { 1215 /* see MSG_BARRIER for purpose/pairing */ 1216 smp_acquire__after_ctrl_dep(); 1217 1218 goto out_unlock1; 1219 } 1220 1221 /* 1222 * ... or see -EAGAIN, acquire the lock to check the message 1223 * again. 1224 */ 1225 ipc_lock_object(&msq->q_perm); 1226 1227 msg = READ_ONCE(msr_d.r_msg); 1228 if (msg != ERR_PTR(-EAGAIN)) 1229 goto out_unlock0; 1230 1231 list_del(&msr_d.r_list); 1232 if (signal_pending(current)) { 1233 msg = ERR_PTR(-ERESTARTNOHAND); 1234 goto out_unlock0; 1235 } 1236 1237 ipc_unlock_object(&msq->q_perm); 1238 } 1239 1240 out_unlock0: 1241 ipc_unlock_object(&msq->q_perm); 1242 wake_up_q(&wake_q); 1243 out_unlock1: 1244 rcu_read_unlock(); 1245 if (IS_ERR(msg)) { 1246 free_copy(copy); 1247 return PTR_ERR(msg); 1248 } 1249 1250 bufsz = msg_handler(buf, msg, bufsz); 1251 free_msg(msg); 1252 1253 return bufsz; 1254 } 1255 1256 long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz, 1257 long msgtyp, int msgflg) 1258 { 1259 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill); 1260 } 1261 1262 SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, 1263 long, msgtyp, int, msgflg) 1264 { 1265 return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg); 1266 } 1267 1268 #ifdef CONFIG_COMPAT 1269 static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) 1270 { 1271 struct compat_msgbuf __user *msgp = dest; 1272 size_t msgsz; 1273 1274 if (put_user(msg->m_type, &msgp->mtype)) 1275 return -EFAULT; 1276 1277 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; 1278 if (store_msg(msgp->mtext, msg, msgsz)) 1279 return -EFAULT; 1280 return msgsz; 1281 } 1282 1283 long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, 1284 compat_long_t msgtyp, int msgflg) 1285 { 1286 return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp, 1287 msgflg, compat_do_msg_fill); 1288 } 1289 1290 COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp, 1291 compat_ssize_t, msgsz, compat_long_t, msgtyp, 1292 int, msgflg) 1293 { 1294 return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg); 1295 } 1296 #endif 1297 1298 void msg_init_ns(struct ipc_namespace *ns) 1299 { 1300 ns->msg_ctlmax = MSGMAX; 1301 ns->msg_ctlmnb = MSGMNB; 1302 ns->msg_ctlmni = MSGMNI; 1303 1304 atomic_set(&ns->msg_bytes, 0); 1305 atomic_set(&ns->msg_hdrs, 0); 1306 ipc_init_ids(&ns->ids[IPC_MSG_IDS]); 1307 } 1308 1309 #ifdef CONFIG_IPC_NS 1310 void msg_exit_ns(struct ipc_namespace *ns) 1311 { 1312 free_ipcs(ns, &msg_ids(ns), freeque); 1313 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr); 1314 rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht); 1315 } 1316 #endif 1317 1318 #ifdef CONFIG_PROC_FS 1319 static int sysvipc_msg_proc_show(struct seq_file *s, void *it) 1320 { 1321 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s); 1322 struct user_namespace *user_ns = seq_user_ns(s); 1323 struct kern_ipc_perm *ipcp = it; 1324 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); 1325 1326 seq_printf(s, 1327 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n", 1328 msq->q_perm.key, 1329 msq->q_perm.id, 1330 msq->q_perm.mode, 1331 msq->q_cbytes, 1332 msq->q_qnum, 1333 pid_nr_ns(msq->q_lspid, pid_ns), 1334 pid_nr_ns(msq->q_lrpid, pid_ns), 1335 from_kuid_munged(user_ns, msq->q_perm.uid), 1336 from_kgid_munged(user_ns, msq->q_perm.gid), 1337 from_kuid_munged(user_ns, msq->q_perm.cuid), 1338 from_kgid_munged(user_ns, msq->q_perm.cgid), 1339 msq->q_stime, 1340 msq->q_rtime, 1341 msq->q_ctime); 1342 1343 return 0; 1344 } 1345 #endif 1346 1347 void __init msg_init(void) 1348 { 1349 msg_init_ns(&init_ipc_ns); 1350 1351 ipc_init_proc_interface("sysvipc/msg", 1352 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", 1353 IPC_MSG_IDS, sysvipc_msg_proc_show); 1354 } 1355