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) { 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 { 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 err = -EACCES; 516 if (ipcperms(ns, &msq->q_perm, S_IRUGO)) 517 goto out_unlock; 518 519 err = security_msg_queue_msgctl(&msq->q_perm, cmd); 520 if (err) 521 goto out_unlock; 522 523 ipc_lock_object(&msq->q_perm); 524 525 if (!ipc_valid_object(&msq->q_perm)) { 526 ipc_unlock_object(&msq->q_perm); 527 err = -EIDRM; 528 goto out_unlock; 529 } 530 531 kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm); 532 p->msg_stime = msq->q_stime; 533 p->msg_rtime = msq->q_rtime; 534 p->msg_ctime = msq->q_ctime; 535 p->msg_cbytes = msq->q_cbytes; 536 p->msg_qnum = msq->q_qnum; 537 p->msg_qbytes = msq->q_qbytes; 538 p->msg_lspid = pid_vnr(msq->q_lspid); 539 p->msg_lrpid = pid_vnr(msq->q_lrpid); 540 541 ipc_unlock_object(&msq->q_perm); 542 rcu_read_unlock(); 543 return id; 544 545 out_unlock: 546 rcu_read_unlock(); 547 return err; 548 } 549 550 long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) 551 { 552 int version; 553 struct ipc_namespace *ns; 554 struct msqid64_ds msqid64; 555 int err; 556 557 if (msqid < 0 || cmd < 0) 558 return -EINVAL; 559 560 version = ipc_parse_version(&cmd); 561 ns = current->nsproxy->ipc_ns; 562 563 switch (cmd) { 564 case IPC_INFO: 565 case MSG_INFO: { 566 struct msginfo msginfo; 567 err = msgctl_info(ns, msqid, cmd, &msginfo); 568 if (err < 0) 569 return err; 570 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) 571 err = -EFAULT; 572 return err; 573 } 574 case MSG_STAT: /* msqid is an index rather than a msg queue id */ 575 case IPC_STAT: 576 err = msgctl_stat(ns, msqid, cmd, &msqid64); 577 if (err < 0) 578 return err; 579 if (copy_msqid_to_user(buf, &msqid64, version)) 580 err = -EFAULT; 581 return err; 582 case IPC_SET: 583 if (copy_msqid_from_user(&msqid64, buf, version)) 584 return -EFAULT; 585 /* fallthru */ 586 case IPC_RMID: 587 return msgctl_down(ns, msqid, cmd, &msqid64); 588 default: 589 return -EINVAL; 590 } 591 } 592 593 SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) 594 { 595 return ksys_msgctl(msqid, cmd, buf); 596 } 597 598 #ifdef CONFIG_COMPAT 599 600 struct compat_msqid_ds { 601 struct compat_ipc_perm msg_perm; 602 compat_uptr_t msg_first; 603 compat_uptr_t msg_last; 604 compat_time_t msg_stime; 605 compat_time_t msg_rtime; 606 compat_time_t msg_ctime; 607 compat_ulong_t msg_lcbytes; 608 compat_ulong_t msg_lqbytes; 609 unsigned short msg_cbytes; 610 unsigned short msg_qnum; 611 unsigned short msg_qbytes; 612 compat_ipc_pid_t msg_lspid; 613 compat_ipc_pid_t msg_lrpid; 614 }; 615 616 static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf, 617 int version) 618 { 619 memset(out, 0, sizeof(*out)); 620 if (version == IPC_64) { 621 struct compat_msqid64_ds __user *p = buf; 622 if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm)) 623 return -EFAULT; 624 if (get_user(out->msg_qbytes, &p->msg_qbytes)) 625 return -EFAULT; 626 } else { 627 struct compat_msqid_ds __user *p = buf; 628 if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm)) 629 return -EFAULT; 630 if (get_user(out->msg_qbytes, &p->msg_qbytes)) 631 return -EFAULT; 632 } 633 return 0; 634 } 635 636 static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in, 637 int version) 638 { 639 if (version == IPC_64) { 640 struct compat_msqid64_ds v; 641 memset(&v, 0, sizeof(v)); 642 to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm); 643 v.msg_stime = in->msg_stime; 644 v.msg_rtime = in->msg_rtime; 645 v.msg_ctime = in->msg_ctime; 646 v.msg_cbytes = in->msg_cbytes; 647 v.msg_qnum = in->msg_qnum; 648 v.msg_qbytes = in->msg_qbytes; 649 v.msg_lspid = in->msg_lspid; 650 v.msg_lrpid = in->msg_lrpid; 651 return copy_to_user(buf, &v, sizeof(v)); 652 } else { 653 struct compat_msqid_ds v; 654 memset(&v, 0, sizeof(v)); 655 to_compat_ipc_perm(&v.msg_perm, &in->msg_perm); 656 v.msg_stime = in->msg_stime; 657 v.msg_rtime = in->msg_rtime; 658 v.msg_ctime = in->msg_ctime; 659 v.msg_cbytes = in->msg_cbytes; 660 v.msg_qnum = in->msg_qnum; 661 v.msg_qbytes = in->msg_qbytes; 662 v.msg_lspid = in->msg_lspid; 663 v.msg_lrpid = in->msg_lrpid; 664 return copy_to_user(buf, &v, sizeof(v)); 665 } 666 } 667 668 long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr) 669 { 670 struct ipc_namespace *ns; 671 int err; 672 struct msqid64_ds msqid64; 673 int version = compat_ipc_parse_version(&cmd); 674 675 ns = current->nsproxy->ipc_ns; 676 677 if (msqid < 0 || cmd < 0) 678 return -EINVAL; 679 680 switch (cmd & (~IPC_64)) { 681 case IPC_INFO: 682 case MSG_INFO: { 683 struct msginfo msginfo; 684 err = msgctl_info(ns, msqid, cmd, &msginfo); 685 if (err < 0) 686 return err; 687 if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo))) 688 err = -EFAULT; 689 return err; 690 } 691 case IPC_STAT: 692 case MSG_STAT: 693 err = msgctl_stat(ns, msqid, cmd, &msqid64); 694 if (err < 0) 695 return err; 696 if (copy_compat_msqid_to_user(uptr, &msqid64, version)) 697 err = -EFAULT; 698 return err; 699 case IPC_SET: 700 if (copy_compat_msqid_from_user(&msqid64, uptr, version)) 701 return -EFAULT; 702 /* fallthru */ 703 case IPC_RMID: 704 return msgctl_down(ns, msqid, cmd, &msqid64); 705 default: 706 return -EINVAL; 707 } 708 } 709 710 COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr) 711 { 712 return compat_ksys_msgctl(msqid, cmd, uptr); 713 } 714 #endif 715 716 static int testmsg(struct msg_msg *msg, long type, int mode) 717 { 718 switch (mode) { 719 case SEARCH_ANY: 720 case SEARCH_NUMBER: 721 return 1; 722 case SEARCH_LESSEQUAL: 723 if (msg->m_type <= type) 724 return 1; 725 break; 726 case SEARCH_EQUAL: 727 if (msg->m_type == type) 728 return 1; 729 break; 730 case SEARCH_NOTEQUAL: 731 if (msg->m_type != type) 732 return 1; 733 break; 734 } 735 return 0; 736 } 737 738 static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg, 739 struct wake_q_head *wake_q) 740 { 741 struct msg_receiver *msr, *t; 742 743 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { 744 if (testmsg(msg, msr->r_msgtype, msr->r_mode) && 745 !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk, 746 msr->r_msgtype, msr->r_mode)) { 747 748 list_del(&msr->r_list); 749 if (msr->r_maxsize < msg->m_ts) { 750 wake_q_add(wake_q, msr->r_tsk); 751 WRITE_ONCE(msr->r_msg, ERR_PTR(-E2BIG)); 752 } else { 753 ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk)); 754 msq->q_rtime = get_seconds(); 755 756 wake_q_add(wake_q, msr->r_tsk); 757 WRITE_ONCE(msr->r_msg, msg); 758 return 1; 759 } 760 } 761 } 762 763 return 0; 764 } 765 766 static long do_msgsnd(int msqid, long mtype, void __user *mtext, 767 size_t msgsz, int msgflg) 768 { 769 struct msg_queue *msq; 770 struct msg_msg *msg; 771 int err; 772 struct ipc_namespace *ns; 773 DEFINE_WAKE_Q(wake_q); 774 775 ns = current->nsproxy->ipc_ns; 776 777 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0) 778 return -EINVAL; 779 if (mtype < 1) 780 return -EINVAL; 781 782 msg = load_msg(mtext, msgsz); 783 if (IS_ERR(msg)) 784 return PTR_ERR(msg); 785 786 msg->m_type = mtype; 787 msg->m_ts = msgsz; 788 789 rcu_read_lock(); 790 msq = msq_obtain_object_check(ns, msqid); 791 if (IS_ERR(msq)) { 792 err = PTR_ERR(msq); 793 goto out_unlock1; 794 } 795 796 ipc_lock_object(&msq->q_perm); 797 798 for (;;) { 799 struct msg_sender s; 800 801 err = -EACCES; 802 if (ipcperms(ns, &msq->q_perm, S_IWUGO)) 803 goto out_unlock0; 804 805 /* raced with RMID? */ 806 if (!ipc_valid_object(&msq->q_perm)) { 807 err = -EIDRM; 808 goto out_unlock0; 809 } 810 811 err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg); 812 if (err) 813 goto out_unlock0; 814 815 if (msg_fits_inqueue(msq, msgsz)) 816 break; 817 818 /* queue full, wait: */ 819 if (msgflg & IPC_NOWAIT) { 820 err = -EAGAIN; 821 goto out_unlock0; 822 } 823 824 /* enqueue the sender and prepare to block */ 825 ss_add(msq, &s, msgsz); 826 827 if (!ipc_rcu_getref(&msq->q_perm)) { 828 err = -EIDRM; 829 goto out_unlock0; 830 } 831 832 ipc_unlock_object(&msq->q_perm); 833 rcu_read_unlock(); 834 schedule(); 835 836 rcu_read_lock(); 837 ipc_lock_object(&msq->q_perm); 838 839 ipc_rcu_putref(&msq->q_perm, msg_rcu_free); 840 /* raced with RMID? */ 841 if (!ipc_valid_object(&msq->q_perm)) { 842 err = -EIDRM; 843 goto out_unlock0; 844 } 845 ss_del(&s); 846 847 if (signal_pending(current)) { 848 err = -ERESTARTNOHAND; 849 goto out_unlock0; 850 } 851 852 } 853 854 ipc_update_pid(&msq->q_lspid, task_tgid(current)); 855 msq->q_stime = get_seconds(); 856 857 if (!pipelined_send(msq, msg, &wake_q)) { 858 /* no one is waiting for this message, enqueue it */ 859 list_add_tail(&msg->m_list, &msq->q_messages); 860 msq->q_cbytes += msgsz; 861 msq->q_qnum++; 862 atomic_add(msgsz, &ns->msg_bytes); 863 atomic_inc(&ns->msg_hdrs); 864 } 865 866 err = 0; 867 msg = NULL; 868 869 out_unlock0: 870 ipc_unlock_object(&msq->q_perm); 871 wake_up_q(&wake_q); 872 out_unlock1: 873 rcu_read_unlock(); 874 if (msg != NULL) 875 free_msg(msg); 876 return err; 877 } 878 879 long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, 880 int msgflg) 881 { 882 long mtype; 883 884 if (get_user(mtype, &msgp->mtype)) 885 return -EFAULT; 886 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg); 887 } 888 889 SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, 890 int, msgflg) 891 { 892 return ksys_msgsnd(msqid, msgp, msgsz, msgflg); 893 } 894 895 #ifdef CONFIG_COMPAT 896 897 struct compat_msgbuf { 898 compat_long_t mtype; 899 char mtext[1]; 900 }; 901 902 long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp, 903 compat_ssize_t msgsz, int msgflg) 904 { 905 struct compat_msgbuf __user *up = compat_ptr(msgp); 906 compat_long_t mtype; 907 908 if (get_user(mtype, &up->mtype)) 909 return -EFAULT; 910 return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg); 911 } 912 913 COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp, 914 compat_ssize_t, msgsz, int, msgflg) 915 { 916 return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg); 917 } 918 #endif 919 920 static inline int convert_mode(long *msgtyp, int msgflg) 921 { 922 if (msgflg & MSG_COPY) 923 return SEARCH_NUMBER; 924 /* 925 * find message of correct type. 926 * msgtyp = 0 => get first. 927 * msgtyp > 0 => get first message of matching type. 928 * msgtyp < 0 => get message with least type must be < abs(msgtype). 929 */ 930 if (*msgtyp == 0) 931 return SEARCH_ANY; 932 if (*msgtyp < 0) { 933 if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */ 934 *msgtyp = LONG_MAX; 935 else 936 *msgtyp = -*msgtyp; 937 return SEARCH_LESSEQUAL; 938 } 939 if (msgflg & MSG_EXCEPT) 940 return SEARCH_NOTEQUAL; 941 return SEARCH_EQUAL; 942 } 943 944 static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) 945 { 946 struct msgbuf __user *msgp = dest; 947 size_t msgsz; 948 949 if (put_user(msg->m_type, &msgp->mtype)) 950 return -EFAULT; 951 952 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; 953 if (store_msg(msgp->mtext, msg, msgsz)) 954 return -EFAULT; 955 return msgsz; 956 } 957 958 #ifdef CONFIG_CHECKPOINT_RESTORE 959 /* 960 * This function creates new kernel message structure, large enough to store 961 * bufsz message bytes. 962 */ 963 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) 964 { 965 struct msg_msg *copy; 966 967 /* 968 * Create dummy message to copy real message to. 969 */ 970 copy = load_msg(buf, bufsz); 971 if (!IS_ERR(copy)) 972 copy->m_ts = bufsz; 973 return copy; 974 } 975 976 static inline void free_copy(struct msg_msg *copy) 977 { 978 if (copy) 979 free_msg(copy); 980 } 981 #else 982 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) 983 { 984 return ERR_PTR(-ENOSYS); 985 } 986 987 static inline void free_copy(struct msg_msg *copy) 988 { 989 } 990 #endif 991 992 static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode) 993 { 994 struct msg_msg *msg, *found = NULL; 995 long count = 0; 996 997 list_for_each_entry(msg, &msq->q_messages, m_list) { 998 if (testmsg(msg, *msgtyp, mode) && 999 !security_msg_queue_msgrcv(&msq->q_perm, msg, current, 1000 *msgtyp, mode)) { 1001 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) { 1002 *msgtyp = msg->m_type - 1; 1003 found = msg; 1004 } else if (mode == SEARCH_NUMBER) { 1005 if (*msgtyp == count) 1006 return msg; 1007 } else 1008 return msg; 1009 count++; 1010 } 1011 } 1012 1013 return found ?: ERR_PTR(-EAGAIN); 1014 } 1015 1016 static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg, 1017 long (*msg_handler)(void __user *, struct msg_msg *, size_t)) 1018 { 1019 int mode; 1020 struct msg_queue *msq; 1021 struct ipc_namespace *ns; 1022 struct msg_msg *msg, *copy = NULL; 1023 DEFINE_WAKE_Q(wake_q); 1024 1025 ns = current->nsproxy->ipc_ns; 1026 1027 if (msqid < 0 || (long) bufsz < 0) 1028 return -EINVAL; 1029 1030 if (msgflg & MSG_COPY) { 1031 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT)) 1032 return -EINVAL; 1033 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); 1034 if (IS_ERR(copy)) 1035 return PTR_ERR(copy); 1036 } 1037 mode = convert_mode(&msgtyp, msgflg); 1038 1039 rcu_read_lock(); 1040 msq = msq_obtain_object_check(ns, msqid); 1041 if (IS_ERR(msq)) { 1042 rcu_read_unlock(); 1043 free_copy(copy); 1044 return PTR_ERR(msq); 1045 } 1046 1047 for (;;) { 1048 struct msg_receiver msr_d; 1049 1050 msg = ERR_PTR(-EACCES); 1051 if (ipcperms(ns, &msq->q_perm, S_IRUGO)) 1052 goto out_unlock1; 1053 1054 ipc_lock_object(&msq->q_perm); 1055 1056 /* raced with RMID? */ 1057 if (!ipc_valid_object(&msq->q_perm)) { 1058 msg = ERR_PTR(-EIDRM); 1059 goto out_unlock0; 1060 } 1061 1062 msg = find_msg(msq, &msgtyp, mode); 1063 if (!IS_ERR(msg)) { 1064 /* 1065 * Found a suitable message. 1066 * Unlink it from the queue. 1067 */ 1068 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { 1069 msg = ERR_PTR(-E2BIG); 1070 goto out_unlock0; 1071 } 1072 /* 1073 * If we are copying, then do not unlink message and do 1074 * not update queue parameters. 1075 */ 1076 if (msgflg & MSG_COPY) { 1077 msg = copy_msg(msg, copy); 1078 goto out_unlock0; 1079 } 1080 1081 list_del(&msg->m_list); 1082 msq->q_qnum--; 1083 msq->q_rtime = get_seconds(); 1084 ipc_update_pid(&msq->q_lrpid, task_tgid(current)); 1085 msq->q_cbytes -= msg->m_ts; 1086 atomic_sub(msg->m_ts, &ns->msg_bytes); 1087 atomic_dec(&ns->msg_hdrs); 1088 ss_wakeup(msq, &wake_q, false); 1089 1090 goto out_unlock0; 1091 } 1092 1093 /* No message waiting. Wait for a message */ 1094 if (msgflg & IPC_NOWAIT) { 1095 msg = ERR_PTR(-ENOMSG); 1096 goto out_unlock0; 1097 } 1098 1099 list_add_tail(&msr_d.r_list, &msq->q_receivers); 1100 msr_d.r_tsk = current; 1101 msr_d.r_msgtype = msgtyp; 1102 msr_d.r_mode = mode; 1103 if (msgflg & MSG_NOERROR) 1104 msr_d.r_maxsize = INT_MAX; 1105 else 1106 msr_d.r_maxsize = bufsz; 1107 msr_d.r_msg = ERR_PTR(-EAGAIN); 1108 __set_current_state(TASK_INTERRUPTIBLE); 1109 1110 ipc_unlock_object(&msq->q_perm); 1111 rcu_read_unlock(); 1112 schedule(); 1113 1114 /* 1115 * Lockless receive, part 1: 1116 * We don't hold a reference to the queue and getting a 1117 * reference would defeat the idea of a lockless operation, 1118 * thus the code relies on rcu to guarantee the existence of 1119 * msq: 1120 * Prior to destruction, expunge_all(-EIRDM) changes r_msg. 1121 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. 1122 */ 1123 rcu_read_lock(); 1124 1125 /* 1126 * Lockless receive, part 2: 1127 * The work in pipelined_send() and expunge_all(): 1128 * - Set pointer to message 1129 * - Queue the receiver task for later wakeup 1130 * - Wake up the process after the lock is dropped. 1131 * 1132 * Should the process wake up before this wakeup (due to a 1133 * signal) it will either see the message and continue ... 1134 */ 1135 msg = READ_ONCE(msr_d.r_msg); 1136 if (msg != ERR_PTR(-EAGAIN)) 1137 goto out_unlock1; 1138 1139 /* 1140 * ... or see -EAGAIN, acquire the lock to check the message 1141 * again. 1142 */ 1143 ipc_lock_object(&msq->q_perm); 1144 1145 msg = msr_d.r_msg; 1146 if (msg != ERR_PTR(-EAGAIN)) 1147 goto out_unlock0; 1148 1149 list_del(&msr_d.r_list); 1150 if (signal_pending(current)) { 1151 msg = ERR_PTR(-ERESTARTNOHAND); 1152 goto out_unlock0; 1153 } 1154 1155 ipc_unlock_object(&msq->q_perm); 1156 } 1157 1158 out_unlock0: 1159 ipc_unlock_object(&msq->q_perm); 1160 wake_up_q(&wake_q); 1161 out_unlock1: 1162 rcu_read_unlock(); 1163 if (IS_ERR(msg)) { 1164 free_copy(copy); 1165 return PTR_ERR(msg); 1166 } 1167 1168 bufsz = msg_handler(buf, msg, bufsz); 1169 free_msg(msg); 1170 1171 return bufsz; 1172 } 1173 1174 long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz, 1175 long msgtyp, int msgflg) 1176 { 1177 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill); 1178 } 1179 1180 SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, 1181 long, msgtyp, int, msgflg) 1182 { 1183 return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg); 1184 } 1185 1186 #ifdef CONFIG_COMPAT 1187 static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) 1188 { 1189 struct compat_msgbuf __user *msgp = dest; 1190 size_t msgsz; 1191 1192 if (put_user(msg->m_type, &msgp->mtype)) 1193 return -EFAULT; 1194 1195 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; 1196 if (store_msg(msgp->mtext, msg, msgsz)) 1197 return -EFAULT; 1198 return msgsz; 1199 } 1200 1201 long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, 1202 compat_long_t msgtyp, int msgflg) 1203 { 1204 return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp, 1205 msgflg, compat_do_msg_fill); 1206 } 1207 1208 COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp, 1209 compat_ssize_t, msgsz, compat_long_t, msgtyp, 1210 int, msgflg) 1211 { 1212 return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg); 1213 } 1214 #endif 1215 1216 int msg_init_ns(struct ipc_namespace *ns) 1217 { 1218 ns->msg_ctlmax = MSGMAX; 1219 ns->msg_ctlmnb = MSGMNB; 1220 ns->msg_ctlmni = MSGMNI; 1221 1222 atomic_set(&ns->msg_bytes, 0); 1223 atomic_set(&ns->msg_hdrs, 0); 1224 return ipc_init_ids(&ns->ids[IPC_MSG_IDS]); 1225 } 1226 1227 #ifdef CONFIG_IPC_NS 1228 void msg_exit_ns(struct ipc_namespace *ns) 1229 { 1230 free_ipcs(ns, &msg_ids(ns), freeque); 1231 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr); 1232 rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht); 1233 } 1234 #endif 1235 1236 #ifdef CONFIG_PROC_FS 1237 static int sysvipc_msg_proc_show(struct seq_file *s, void *it) 1238 { 1239 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s); 1240 struct user_namespace *user_ns = seq_user_ns(s); 1241 struct kern_ipc_perm *ipcp = it; 1242 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); 1243 1244 seq_printf(s, 1245 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n", 1246 msq->q_perm.key, 1247 msq->q_perm.id, 1248 msq->q_perm.mode, 1249 msq->q_cbytes, 1250 msq->q_qnum, 1251 pid_nr_ns(msq->q_lspid, pid_ns), 1252 pid_nr_ns(msq->q_lrpid, pid_ns), 1253 from_kuid_munged(user_ns, msq->q_perm.uid), 1254 from_kgid_munged(user_ns, msq->q_perm.gid), 1255 from_kuid_munged(user_ns, msq->q_perm.cuid), 1256 from_kgid_munged(user_ns, msq->q_perm.cgid), 1257 msq->q_stime, 1258 msq->q_rtime, 1259 msq->q_ctime); 1260 1261 return 0; 1262 } 1263 #endif 1264 1265 int __init msg_init(void) 1266 { 1267 const int err = msg_init_ns(&init_ipc_ns); 1268 1269 ipc_init_proc_interface("sysvipc/msg", 1270 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", 1271 IPC_MSG_IDS, sysvipc_msg_proc_show); 1272 return err; 1273 } 1274