1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/ipc/msg.c 4 * Copyright (C) 1992 Krishna Balasubramanian 5 * 6 * Removed all the remaining kerneld mess 7 * Catch the -EFAULT stuff properly 8 * Use GFP_KERNEL for messages as in 1.2 9 * Fixed up the unchecked user space derefs 10 * Copyright (C) 1998 Alan Cox & Andi Kleen 11 * 12 * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com> 13 * 14 * mostly rewritten, threaded and wake-one semantics added 15 * MSGMAX limit removed, sysctl's added 16 * (c) 1999 Manfred Spraul <manfred@colorfullife.com> 17 * 18 * support for audit of ipc object properties and permission changes 19 * Dustin Kirkland <dustin.kirkland@us.ibm.com> 20 * 21 * namespaces support 22 * OpenVZ, SWsoft Inc. 23 * Pavel Emelianov <xemul@openvz.org> 24 */ 25 26 #include <linux/capability.h> 27 #include <linux/msg.h> 28 #include <linux/spinlock.h> 29 #include <linux/init.h> 30 #include <linux/mm.h> 31 #include <linux/proc_fs.h> 32 #include <linux/list.h> 33 #include <linux/security.h> 34 #include <linux/sched/wake_q.h> 35 #include <linux/syscalls.h> 36 #include <linux/audit.h> 37 #include <linux/seq_file.h> 38 #include <linux/rwsem.h> 39 #include <linux/nsproxy.h> 40 #include <linux/ipc_namespace.h> 41 #include <linux/rhashtable.h> 42 43 #include <asm/current.h> 44 #include <linux/uaccess.h> 45 #include "util.h" 46 47 /* one msq_queue structure for each present queue on the system */ 48 struct msg_queue { 49 struct kern_ipc_perm q_perm; 50 time64_t q_stime; /* last msgsnd time */ 51 time64_t q_rtime; /* last msgrcv time */ 52 time64_t q_ctime; /* last change time */ 53 unsigned long q_cbytes; /* current number of bytes on queue */ 54 unsigned long q_qnum; /* number of messages in queue */ 55 unsigned long q_qbytes; /* max number of bytes on queue */ 56 struct pid *q_lspid; /* pid of last msgsnd */ 57 struct pid *q_lrpid; /* last receive pid */ 58 59 struct list_head q_messages; 60 struct list_head q_receivers; 61 struct list_head q_senders; 62 } __randomize_layout; 63 64 /* one msg_receiver structure for each sleeping receiver */ 65 struct msg_receiver { 66 struct list_head r_list; 67 struct task_struct *r_tsk; 68 69 int r_mode; 70 long r_msgtype; 71 long r_maxsize; 72 73 struct msg_msg *r_msg; 74 }; 75 76 /* one msg_sender for each sleeping sender */ 77 struct msg_sender { 78 struct list_head list; 79 struct task_struct *tsk; 80 size_t msgsz; 81 }; 82 83 #define SEARCH_ANY 1 84 #define SEARCH_EQUAL 2 85 #define SEARCH_NOTEQUAL 3 86 #define SEARCH_LESSEQUAL 4 87 #define SEARCH_NUMBER 5 88 89 #define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS]) 90 91 static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id) 92 { 93 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&msg_ids(ns), id); 94 95 if (IS_ERR(ipcp)) 96 return ERR_CAST(ipcp); 97 98 return container_of(ipcp, struct msg_queue, q_perm); 99 } 100 101 static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns, 102 int id) 103 { 104 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id); 105 106 if (IS_ERR(ipcp)) 107 return ERR_CAST(ipcp); 108 109 return container_of(ipcp, struct msg_queue, q_perm); 110 } 111 112 static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s) 113 { 114 ipc_rmid(&msg_ids(ns), &s->q_perm); 115 } 116 117 static void msg_rcu_free(struct rcu_head *head) 118 { 119 struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu); 120 struct msg_queue *msq = container_of(p, struct msg_queue, q_perm); 121 122 security_msg_queue_free(&msq->q_perm); 123 kvfree(msq); 124 } 125 126 /** 127 * newque - Create a new msg queue 128 * @ns: namespace 129 * @params: ptr to the structure that contains the key and msgflg 130 * 131 * Called with msg_ids.rwsem held (writer) 132 */ 133 static int newque(struct ipc_namespace *ns, struct ipc_params *params) 134 { 135 struct msg_queue *msq; 136 int retval; 137 key_t key = params->key; 138 int msgflg = params->flg; 139 140 msq = kvmalloc(sizeof(*msq), GFP_KERNEL); 141 if (unlikely(!msq)) 142 return -ENOMEM; 143 144 msq->q_perm.mode = msgflg & S_IRWXUGO; 145 msq->q_perm.key = key; 146 147 msq->q_perm.security = NULL; 148 retval = security_msg_queue_alloc(&msq->q_perm); 149 if (retval) { 150 kvfree(msq); 151 return retval; 152 } 153 154 msq->q_stime = msq->q_rtime = 0; 155 msq->q_ctime = ktime_get_real_seconds(); 156 msq->q_cbytes = msq->q_qnum = 0; 157 msq->q_qbytes = ns->msg_ctlmnb; 158 msq->q_lspid = msq->q_lrpid = NULL; 159 INIT_LIST_HEAD(&msq->q_messages); 160 INIT_LIST_HEAD(&msq->q_receivers); 161 INIT_LIST_HEAD(&msq->q_senders); 162 163 /* ipc_addid() locks msq upon success. */ 164 retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); 165 if (retval < 0) { 166 ipc_rcu_putref(&msq->q_perm, msg_rcu_free); 167 return retval; 168 } 169 170 ipc_unlock_object(&msq->q_perm); 171 rcu_read_unlock(); 172 173 return msq->q_perm.id; 174 } 175 176 static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz) 177 { 178 return msgsz + msq->q_cbytes <= msq->q_qbytes && 179 1 + msq->q_qnum <= msq->q_qbytes; 180 } 181 182 static inline void ss_add(struct msg_queue *msq, 183 struct msg_sender *mss, size_t msgsz) 184 { 185 mss->tsk = current; 186 mss->msgsz = msgsz; 187 __set_current_state(TASK_INTERRUPTIBLE); 188 list_add_tail(&mss->list, &msq->q_senders); 189 } 190 191 static inline void ss_del(struct msg_sender *mss) 192 { 193 if (mss->list.next) 194 list_del(&mss->list); 195 } 196 197 static void ss_wakeup(struct msg_queue *msq, 198 struct wake_q_head *wake_q, bool kill) 199 { 200 struct msg_sender *mss, *t; 201 struct task_struct *stop_tsk = NULL; 202 struct list_head *h = &msq->q_senders; 203 204 list_for_each_entry_safe(mss, t, h, list) { 205 if (kill) 206 mss->list.next = NULL; 207 208 /* 209 * Stop at the first task we don't wakeup, 210 * we've already iterated the original 211 * sender queue. 212 */ 213 else if (stop_tsk == mss->tsk) 214 break; 215 /* 216 * We are not in an EIDRM scenario here, therefore 217 * verify that we really need to wakeup the task. 218 * To maintain current semantics and wakeup order, 219 * move the sender to the tail on behalf of the 220 * blocked task. 221 */ 222 else if (!msg_fits_inqueue(msq, mss->msgsz)) { 223 if (!stop_tsk) 224 stop_tsk = mss->tsk; 225 226 list_move_tail(&mss->list, &msq->q_senders); 227 continue; 228 } 229 230 wake_q_add(wake_q, mss->tsk); 231 } 232 } 233 234 static void expunge_all(struct msg_queue *msq, int res, 235 struct wake_q_head *wake_q) 236 { 237 struct msg_receiver *msr, *t; 238 239 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { 240 wake_q_add(wake_q, msr->r_tsk); 241 WRITE_ONCE(msr->r_msg, ERR_PTR(res)); 242 } 243 } 244 245 /* 246 * freeque() wakes up waiters on the sender and receiver waiting queue, 247 * removes the message queue from message queue ID IDR, and cleans up all the 248 * messages associated with this queue. 249 * 250 * msg_ids.rwsem (writer) and the spinlock for this message queue are held 251 * before freeque() is called. msg_ids.rwsem remains locked on exit. 252 */ 253 static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) 254 { 255 struct msg_msg *msg, *t; 256 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); 257 DEFINE_WAKE_Q(wake_q); 258 259 expunge_all(msq, -EIDRM, &wake_q); 260 ss_wakeup(msq, &wake_q, true); 261 msg_rmid(ns, msq); 262 ipc_unlock_object(&msq->q_perm); 263 wake_up_q(&wake_q); 264 rcu_read_unlock(); 265 266 list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) { 267 atomic_dec(&ns->msg_hdrs); 268 free_msg(msg); 269 } 270 atomic_sub(msq->q_cbytes, &ns->msg_bytes); 271 ipc_update_pid(&msq->q_lspid, NULL); 272 ipc_update_pid(&msq->q_lrpid, NULL); 273 ipc_rcu_putref(&msq->q_perm, msg_rcu_free); 274 } 275 276 long ksys_msgget(key_t key, int msgflg) 277 { 278 struct ipc_namespace *ns; 279 static const struct ipc_ops msg_ops = { 280 .getnew = newque, 281 .associate = security_msg_queue_associate, 282 }; 283 struct ipc_params msg_params; 284 285 ns = current->nsproxy->ipc_ns; 286 287 msg_params.key = key; 288 msg_params.flg = msgflg; 289 290 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params); 291 } 292 293 SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg) 294 { 295 return ksys_msgget(key, msgflg); 296 } 297 298 static inline unsigned long 299 copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) 300 { 301 switch (version) { 302 case IPC_64: 303 return copy_to_user(buf, in, sizeof(*in)); 304 case IPC_OLD: 305 { 306 struct msqid_ds out; 307 308 memset(&out, 0, sizeof(out)); 309 310 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); 311 312 out.msg_stime = in->msg_stime; 313 out.msg_rtime = in->msg_rtime; 314 out.msg_ctime = in->msg_ctime; 315 316 if (in->msg_cbytes > USHRT_MAX) 317 out.msg_cbytes = USHRT_MAX; 318 else 319 out.msg_cbytes = in->msg_cbytes; 320 out.msg_lcbytes = in->msg_cbytes; 321 322 if (in->msg_qnum > USHRT_MAX) 323 out.msg_qnum = USHRT_MAX; 324 else 325 out.msg_qnum = in->msg_qnum; 326 327 if (in->msg_qbytes > USHRT_MAX) 328 out.msg_qbytes = USHRT_MAX; 329 else 330 out.msg_qbytes = in->msg_qbytes; 331 out.msg_lqbytes = in->msg_qbytes; 332 333 out.msg_lspid = in->msg_lspid; 334 out.msg_lrpid = in->msg_lrpid; 335 336 return copy_to_user(buf, &out, sizeof(out)); 337 } 338 default: 339 return -EINVAL; 340 } 341 } 342 343 static inline unsigned long 344 copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version) 345 { 346 switch (version) { 347 case IPC_64: 348 if (copy_from_user(out, buf, sizeof(*out))) 349 return -EFAULT; 350 return 0; 351 case IPC_OLD: 352 { 353 struct msqid_ds tbuf_old; 354 355 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) 356 return -EFAULT; 357 358 out->msg_perm.uid = tbuf_old.msg_perm.uid; 359 out->msg_perm.gid = tbuf_old.msg_perm.gid; 360 out->msg_perm.mode = tbuf_old.msg_perm.mode; 361 362 if (tbuf_old.msg_qbytes == 0) 363 out->msg_qbytes = tbuf_old.msg_lqbytes; 364 else 365 out->msg_qbytes = tbuf_old.msg_qbytes; 366 367 return 0; 368 } 369 default: 370 return -EINVAL; 371 } 372 } 373 374 /* 375 * This function handles some msgctl commands which require the rwsem 376 * to be held in write mode. 377 * NOTE: no locks must be held, the rwsem is taken inside this function. 378 */ 379 static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, 380 struct msqid64_ds *msqid64) 381 { 382 struct kern_ipc_perm *ipcp; 383 struct msg_queue *msq; 384 int err; 385 386 down_write(&msg_ids(ns).rwsem); 387 rcu_read_lock(); 388 389 ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd, 390 &msqid64->msg_perm, msqid64->msg_qbytes); 391 if (IS_ERR(ipcp)) { 392 err = PTR_ERR(ipcp); 393 goto out_unlock1; 394 } 395 396 msq = container_of(ipcp, struct msg_queue, q_perm); 397 398 err = security_msg_queue_msgctl(&msq->q_perm, cmd); 399 if (err) 400 goto out_unlock1; 401 402 switch (cmd) { 403 case IPC_RMID: 404 ipc_lock_object(&msq->q_perm); 405 /* freeque unlocks the ipc object and rcu */ 406 freeque(ns, ipcp); 407 goto out_up; 408 case IPC_SET: 409 { 410 DEFINE_WAKE_Q(wake_q); 411 412 if (msqid64->msg_qbytes > ns->msg_ctlmnb && 413 !capable(CAP_SYS_RESOURCE)) { 414 err = -EPERM; 415 goto out_unlock1; 416 } 417 418 ipc_lock_object(&msq->q_perm); 419 err = ipc_update_perm(&msqid64->msg_perm, ipcp); 420 if (err) 421 goto out_unlock0; 422 423 msq->q_qbytes = msqid64->msg_qbytes; 424 425 msq->q_ctime = ktime_get_real_seconds(); 426 /* 427 * Sleeping receivers might be excluded by 428 * stricter permissions. 429 */ 430 expunge_all(msq, -EAGAIN, &wake_q); 431 /* 432 * Sleeping senders might be able to send 433 * due to a larger queue size. 434 */ 435 ss_wakeup(msq, &wake_q, false); 436 ipc_unlock_object(&msq->q_perm); 437 wake_up_q(&wake_q); 438 439 goto out_unlock1; 440 } 441 default: 442 err = -EINVAL; 443 goto out_unlock1; 444 } 445 446 out_unlock0: 447 ipc_unlock_object(&msq->q_perm); 448 out_unlock1: 449 rcu_read_unlock(); 450 out_up: 451 up_write(&msg_ids(ns).rwsem); 452 return err; 453 } 454 455 static int msgctl_info(struct ipc_namespace *ns, int msqid, 456 int cmd, struct msginfo *msginfo) 457 { 458 int err; 459 int max_idx; 460 461 /* 462 * We must not return kernel stack data. 463 * due to padding, it's not enough 464 * to set all member fields. 465 */ 466 err = security_msg_queue_msgctl(NULL, cmd); 467 if (err) 468 return err; 469 470 memset(msginfo, 0, sizeof(*msginfo)); 471 msginfo->msgmni = ns->msg_ctlmni; 472 msginfo->msgmax = ns->msg_ctlmax; 473 msginfo->msgmnb = ns->msg_ctlmnb; 474 msginfo->msgssz = MSGSSZ; 475 msginfo->msgseg = MSGSEG; 476 down_read(&msg_ids(ns).rwsem); 477 if (cmd == MSG_INFO) { 478 msginfo->msgpool = msg_ids(ns).in_use; 479 msginfo->msgmap = atomic_read(&ns->msg_hdrs); 480 msginfo->msgtql = atomic_read(&ns->msg_bytes); 481 } else { 482 msginfo->msgmap = MSGMAP; 483 msginfo->msgpool = MSGPOOL; 484 msginfo->msgtql = MSGTQL; 485 } 486 max_idx = ipc_get_maxidx(&msg_ids(ns)); 487 up_read(&msg_ids(ns).rwsem); 488 return (max_idx < 0) ? 0 : max_idx; 489 } 490 491 static int msgctl_stat(struct ipc_namespace *ns, int msqid, 492 int cmd, struct msqid64_ds *p) 493 { 494 struct msg_queue *msq; 495 int err; 496 497 memset(p, 0, sizeof(*p)); 498 499 rcu_read_lock(); 500 if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) { 501 msq = msq_obtain_object(ns, msqid); 502 if (IS_ERR(msq)) { 503 err = PTR_ERR(msq); 504 goto out_unlock; 505 } 506 } else { /* IPC_STAT */ 507 msq = msq_obtain_object_check(ns, msqid); 508 if (IS_ERR(msq)) { 509 err = PTR_ERR(msq); 510 goto out_unlock; 511 } 512 } 513 514 /* see comment for SHM_STAT_ANY */ 515 if (cmd == MSG_STAT_ANY) 516 audit_ipc_obj(&msq->q_perm); 517 else { 518 err = -EACCES; 519 if (ipcperms(ns, &msq->q_perm, S_IRUGO)) 520 goto out_unlock; 521 } 522 523 err = security_msg_queue_msgctl(&msq->q_perm, cmd); 524 if (err) 525 goto out_unlock; 526 527 ipc_lock_object(&msq->q_perm); 528 529 if (!ipc_valid_object(&msq->q_perm)) { 530 ipc_unlock_object(&msq->q_perm); 531 err = -EIDRM; 532 goto out_unlock; 533 } 534 535 kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm); 536 p->msg_stime = msq->q_stime; 537 p->msg_rtime = msq->q_rtime; 538 p->msg_ctime = msq->q_ctime; 539 #ifndef CONFIG_64BIT 540 p->msg_stime_high = msq->q_stime >> 32; 541 p->msg_rtime_high = msq->q_rtime >> 32; 542 p->msg_ctime_high = msq->q_ctime >> 32; 543 #endif 544 p->msg_cbytes = msq->q_cbytes; 545 p->msg_qnum = msq->q_qnum; 546 p->msg_qbytes = msq->q_qbytes; 547 p->msg_lspid = pid_vnr(msq->q_lspid); 548 p->msg_lrpid = pid_vnr(msq->q_lrpid); 549 550 if (cmd == IPC_STAT) { 551 /* 552 * As defined in SUS: 553 * Return 0 on success 554 */ 555 err = 0; 556 } else { 557 /* 558 * MSG_STAT and MSG_STAT_ANY (both Linux specific) 559 * Return the full id, including the sequence number 560 */ 561 err = msq->q_perm.id; 562 } 563 564 ipc_unlock_object(&msq->q_perm); 565 out_unlock: 566 rcu_read_unlock(); 567 return err; 568 } 569 570 static long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf, int version) 571 { 572 struct ipc_namespace *ns; 573 struct msqid64_ds msqid64; 574 int err; 575 576 if (msqid < 0 || cmd < 0) 577 return -EINVAL; 578 579 ns = current->nsproxy->ipc_ns; 580 581 switch (cmd) { 582 case IPC_INFO: 583 case MSG_INFO: { 584 struct msginfo msginfo; 585 err = msgctl_info(ns, msqid, cmd, &msginfo); 586 if (err < 0) 587 return err; 588 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) 589 err = -EFAULT; 590 return err; 591 } 592 case MSG_STAT: /* msqid is an index rather than a msg queue id */ 593 case MSG_STAT_ANY: 594 case IPC_STAT: 595 err = msgctl_stat(ns, msqid, cmd, &msqid64); 596 if (err < 0) 597 return err; 598 if (copy_msqid_to_user(buf, &msqid64, version)) 599 err = -EFAULT; 600 return err; 601 case IPC_SET: 602 if (copy_msqid_from_user(&msqid64, buf, version)) 603 return -EFAULT; 604 /* fallthru */ 605 case IPC_RMID: 606 return msgctl_down(ns, msqid, cmd, &msqid64); 607 default: 608 return -EINVAL; 609 } 610 } 611 612 SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) 613 { 614 return ksys_msgctl(msqid, cmd, buf, IPC_64); 615 } 616 617 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION 618 long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) 619 { 620 int version = ipc_parse_version(&cmd); 621 622 return ksys_msgctl(msqid, cmd, buf, version); 623 } 624 625 SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) 626 { 627 return ksys_old_msgctl(msqid, cmd, buf); 628 } 629 #endif 630 631 #ifdef CONFIG_COMPAT 632 633 struct compat_msqid_ds { 634 struct compat_ipc_perm msg_perm; 635 compat_uptr_t msg_first; 636 compat_uptr_t msg_last; 637 old_time32_t msg_stime; 638 old_time32_t msg_rtime; 639 old_time32_t msg_ctime; 640 compat_ulong_t msg_lcbytes; 641 compat_ulong_t msg_lqbytes; 642 unsigned short msg_cbytes; 643 unsigned short msg_qnum; 644 unsigned short msg_qbytes; 645 compat_ipc_pid_t msg_lspid; 646 compat_ipc_pid_t msg_lrpid; 647 }; 648 649 static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf, 650 int version) 651 { 652 memset(out, 0, sizeof(*out)); 653 if (version == IPC_64) { 654 struct compat_msqid64_ds __user *p = buf; 655 if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm)) 656 return -EFAULT; 657 if (get_user(out->msg_qbytes, &p->msg_qbytes)) 658 return -EFAULT; 659 } else { 660 struct compat_msqid_ds __user *p = buf; 661 if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm)) 662 return -EFAULT; 663 if (get_user(out->msg_qbytes, &p->msg_qbytes)) 664 return -EFAULT; 665 } 666 return 0; 667 } 668 669 static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in, 670 int version) 671 { 672 if (version == IPC_64) { 673 struct compat_msqid64_ds v; 674 memset(&v, 0, sizeof(v)); 675 to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm); 676 v.msg_stime = lower_32_bits(in->msg_stime); 677 v.msg_stime_high = upper_32_bits(in->msg_stime); 678 v.msg_rtime = lower_32_bits(in->msg_rtime); 679 v.msg_rtime_high = upper_32_bits(in->msg_rtime); 680 v.msg_ctime = lower_32_bits(in->msg_ctime); 681 v.msg_ctime_high = upper_32_bits(in->msg_ctime); 682 v.msg_cbytes = in->msg_cbytes; 683 v.msg_qnum = in->msg_qnum; 684 v.msg_qbytes = in->msg_qbytes; 685 v.msg_lspid = in->msg_lspid; 686 v.msg_lrpid = in->msg_lrpid; 687 return copy_to_user(buf, &v, sizeof(v)); 688 } else { 689 struct compat_msqid_ds v; 690 memset(&v, 0, sizeof(v)); 691 to_compat_ipc_perm(&v.msg_perm, &in->msg_perm); 692 v.msg_stime = in->msg_stime; 693 v.msg_rtime = in->msg_rtime; 694 v.msg_ctime = in->msg_ctime; 695 v.msg_cbytes = in->msg_cbytes; 696 v.msg_qnum = in->msg_qnum; 697 v.msg_qbytes = in->msg_qbytes; 698 v.msg_lspid = in->msg_lspid; 699 v.msg_lrpid = in->msg_lrpid; 700 return copy_to_user(buf, &v, sizeof(v)); 701 } 702 } 703 704 static long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr, int version) 705 { 706 struct ipc_namespace *ns; 707 int err; 708 struct msqid64_ds msqid64; 709 710 ns = current->nsproxy->ipc_ns; 711 712 if (msqid < 0 || cmd < 0) 713 return -EINVAL; 714 715 switch (cmd & (~IPC_64)) { 716 case IPC_INFO: 717 case MSG_INFO: { 718 struct msginfo msginfo; 719 err = msgctl_info(ns, msqid, cmd, &msginfo); 720 if (err < 0) 721 return err; 722 if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo))) 723 err = -EFAULT; 724 return err; 725 } 726 case IPC_STAT: 727 case MSG_STAT: 728 case MSG_STAT_ANY: 729 err = msgctl_stat(ns, msqid, cmd, &msqid64); 730 if (err < 0) 731 return err; 732 if (copy_compat_msqid_to_user(uptr, &msqid64, version)) 733 err = -EFAULT; 734 return err; 735 case IPC_SET: 736 if (copy_compat_msqid_from_user(&msqid64, uptr, version)) 737 return -EFAULT; 738 /* fallthru */ 739 case IPC_RMID: 740 return msgctl_down(ns, msqid, cmd, &msqid64); 741 default: 742 return -EINVAL; 743 } 744 } 745 746 COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr) 747 { 748 return compat_ksys_msgctl(msqid, cmd, uptr, IPC_64); 749 } 750 751 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION 752 long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr) 753 { 754 int version = compat_ipc_parse_version(&cmd); 755 756 return compat_ksys_msgctl(msqid, cmd, uptr, version); 757 } 758 759 COMPAT_SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, void __user *, uptr) 760 { 761 return compat_ksys_old_msgctl(msqid, cmd, uptr); 762 } 763 #endif 764 #endif 765 766 static int testmsg(struct msg_msg *msg, long type, int mode) 767 { 768 switch (mode) { 769 case SEARCH_ANY: 770 case SEARCH_NUMBER: 771 return 1; 772 case SEARCH_LESSEQUAL: 773 if (msg->m_type <= type) 774 return 1; 775 break; 776 case SEARCH_EQUAL: 777 if (msg->m_type == type) 778 return 1; 779 break; 780 case SEARCH_NOTEQUAL: 781 if (msg->m_type != type) 782 return 1; 783 break; 784 } 785 return 0; 786 } 787 788 static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg, 789 struct wake_q_head *wake_q) 790 { 791 struct msg_receiver *msr, *t; 792 793 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { 794 if (testmsg(msg, msr->r_msgtype, msr->r_mode) && 795 !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk, 796 msr->r_msgtype, msr->r_mode)) { 797 798 list_del(&msr->r_list); 799 if (msr->r_maxsize < msg->m_ts) { 800 wake_q_add(wake_q, msr->r_tsk); 801 WRITE_ONCE(msr->r_msg, ERR_PTR(-E2BIG)); 802 } else { 803 ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk)); 804 msq->q_rtime = ktime_get_real_seconds(); 805 806 wake_q_add(wake_q, msr->r_tsk); 807 WRITE_ONCE(msr->r_msg, msg); 808 return 1; 809 } 810 } 811 } 812 813 return 0; 814 } 815 816 static long do_msgsnd(int msqid, long mtype, void __user *mtext, 817 size_t msgsz, int msgflg) 818 { 819 struct msg_queue *msq; 820 struct msg_msg *msg; 821 int err; 822 struct ipc_namespace *ns; 823 DEFINE_WAKE_Q(wake_q); 824 825 ns = current->nsproxy->ipc_ns; 826 827 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0) 828 return -EINVAL; 829 if (mtype < 1) 830 return -EINVAL; 831 832 msg = load_msg(mtext, msgsz); 833 if (IS_ERR(msg)) 834 return PTR_ERR(msg); 835 836 msg->m_type = mtype; 837 msg->m_ts = msgsz; 838 839 rcu_read_lock(); 840 msq = msq_obtain_object_check(ns, msqid); 841 if (IS_ERR(msq)) { 842 err = PTR_ERR(msq); 843 goto out_unlock1; 844 } 845 846 ipc_lock_object(&msq->q_perm); 847 848 for (;;) { 849 struct msg_sender s; 850 851 err = -EACCES; 852 if (ipcperms(ns, &msq->q_perm, S_IWUGO)) 853 goto out_unlock0; 854 855 /* raced with RMID? */ 856 if (!ipc_valid_object(&msq->q_perm)) { 857 err = -EIDRM; 858 goto out_unlock0; 859 } 860 861 err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg); 862 if (err) 863 goto out_unlock0; 864 865 if (msg_fits_inqueue(msq, msgsz)) 866 break; 867 868 /* queue full, wait: */ 869 if (msgflg & IPC_NOWAIT) { 870 err = -EAGAIN; 871 goto out_unlock0; 872 } 873 874 /* enqueue the sender and prepare to block */ 875 ss_add(msq, &s, msgsz); 876 877 if (!ipc_rcu_getref(&msq->q_perm)) { 878 err = -EIDRM; 879 goto out_unlock0; 880 } 881 882 ipc_unlock_object(&msq->q_perm); 883 rcu_read_unlock(); 884 schedule(); 885 886 rcu_read_lock(); 887 ipc_lock_object(&msq->q_perm); 888 889 ipc_rcu_putref(&msq->q_perm, msg_rcu_free); 890 /* raced with RMID? */ 891 if (!ipc_valid_object(&msq->q_perm)) { 892 err = -EIDRM; 893 goto out_unlock0; 894 } 895 ss_del(&s); 896 897 if (signal_pending(current)) { 898 err = -ERESTARTNOHAND; 899 goto out_unlock0; 900 } 901 902 } 903 904 ipc_update_pid(&msq->q_lspid, task_tgid(current)); 905 msq->q_stime = ktime_get_real_seconds(); 906 907 if (!pipelined_send(msq, msg, &wake_q)) { 908 /* no one is waiting for this message, enqueue it */ 909 list_add_tail(&msg->m_list, &msq->q_messages); 910 msq->q_cbytes += msgsz; 911 msq->q_qnum++; 912 atomic_add(msgsz, &ns->msg_bytes); 913 atomic_inc(&ns->msg_hdrs); 914 } 915 916 err = 0; 917 msg = NULL; 918 919 out_unlock0: 920 ipc_unlock_object(&msq->q_perm); 921 wake_up_q(&wake_q); 922 out_unlock1: 923 rcu_read_unlock(); 924 if (msg != NULL) 925 free_msg(msg); 926 return err; 927 } 928 929 long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, 930 int msgflg) 931 { 932 long mtype; 933 934 if (get_user(mtype, &msgp->mtype)) 935 return -EFAULT; 936 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg); 937 } 938 939 SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, 940 int, msgflg) 941 { 942 return ksys_msgsnd(msqid, msgp, msgsz, msgflg); 943 } 944 945 #ifdef CONFIG_COMPAT 946 947 struct compat_msgbuf { 948 compat_long_t mtype; 949 char mtext[1]; 950 }; 951 952 long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp, 953 compat_ssize_t msgsz, int msgflg) 954 { 955 struct compat_msgbuf __user *up = compat_ptr(msgp); 956 compat_long_t mtype; 957 958 if (get_user(mtype, &up->mtype)) 959 return -EFAULT; 960 return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg); 961 } 962 963 COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp, 964 compat_ssize_t, msgsz, int, msgflg) 965 { 966 return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg); 967 } 968 #endif 969 970 static inline int convert_mode(long *msgtyp, int msgflg) 971 { 972 if (msgflg & MSG_COPY) 973 return SEARCH_NUMBER; 974 /* 975 * find message of correct type. 976 * msgtyp = 0 => get first. 977 * msgtyp > 0 => get first message of matching type. 978 * msgtyp < 0 => get message with least type must be < abs(msgtype). 979 */ 980 if (*msgtyp == 0) 981 return SEARCH_ANY; 982 if (*msgtyp < 0) { 983 if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */ 984 *msgtyp = LONG_MAX; 985 else 986 *msgtyp = -*msgtyp; 987 return SEARCH_LESSEQUAL; 988 } 989 if (msgflg & MSG_EXCEPT) 990 return SEARCH_NOTEQUAL; 991 return SEARCH_EQUAL; 992 } 993 994 static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) 995 { 996 struct msgbuf __user *msgp = dest; 997 size_t msgsz; 998 999 if (put_user(msg->m_type, &msgp->mtype)) 1000 return -EFAULT; 1001 1002 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; 1003 if (store_msg(msgp->mtext, msg, msgsz)) 1004 return -EFAULT; 1005 return msgsz; 1006 } 1007 1008 #ifdef CONFIG_CHECKPOINT_RESTORE 1009 /* 1010 * This function creates new kernel message structure, large enough to store 1011 * bufsz message bytes. 1012 */ 1013 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) 1014 { 1015 struct msg_msg *copy; 1016 1017 /* 1018 * Create dummy message to copy real message to. 1019 */ 1020 copy = load_msg(buf, bufsz); 1021 if (!IS_ERR(copy)) 1022 copy->m_ts = bufsz; 1023 return copy; 1024 } 1025 1026 static inline void free_copy(struct msg_msg *copy) 1027 { 1028 if (copy) 1029 free_msg(copy); 1030 } 1031 #else 1032 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) 1033 { 1034 return ERR_PTR(-ENOSYS); 1035 } 1036 1037 static inline void free_copy(struct msg_msg *copy) 1038 { 1039 } 1040 #endif 1041 1042 static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode) 1043 { 1044 struct msg_msg *msg, *found = NULL; 1045 long count = 0; 1046 1047 list_for_each_entry(msg, &msq->q_messages, m_list) { 1048 if (testmsg(msg, *msgtyp, mode) && 1049 !security_msg_queue_msgrcv(&msq->q_perm, msg, current, 1050 *msgtyp, mode)) { 1051 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) { 1052 *msgtyp = msg->m_type - 1; 1053 found = msg; 1054 } else if (mode == SEARCH_NUMBER) { 1055 if (*msgtyp == count) 1056 return msg; 1057 } else 1058 return msg; 1059 count++; 1060 } 1061 } 1062 1063 return found ?: ERR_PTR(-EAGAIN); 1064 } 1065 1066 static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg, 1067 long (*msg_handler)(void __user *, struct msg_msg *, size_t)) 1068 { 1069 int mode; 1070 struct msg_queue *msq; 1071 struct ipc_namespace *ns; 1072 struct msg_msg *msg, *copy = NULL; 1073 DEFINE_WAKE_Q(wake_q); 1074 1075 ns = current->nsproxy->ipc_ns; 1076 1077 if (msqid < 0 || (long) bufsz < 0) 1078 return -EINVAL; 1079 1080 if (msgflg & MSG_COPY) { 1081 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT)) 1082 return -EINVAL; 1083 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); 1084 if (IS_ERR(copy)) 1085 return PTR_ERR(copy); 1086 } 1087 mode = convert_mode(&msgtyp, msgflg); 1088 1089 rcu_read_lock(); 1090 msq = msq_obtain_object_check(ns, msqid); 1091 if (IS_ERR(msq)) { 1092 rcu_read_unlock(); 1093 free_copy(copy); 1094 return PTR_ERR(msq); 1095 } 1096 1097 for (;;) { 1098 struct msg_receiver msr_d; 1099 1100 msg = ERR_PTR(-EACCES); 1101 if (ipcperms(ns, &msq->q_perm, S_IRUGO)) 1102 goto out_unlock1; 1103 1104 ipc_lock_object(&msq->q_perm); 1105 1106 /* raced with RMID? */ 1107 if (!ipc_valid_object(&msq->q_perm)) { 1108 msg = ERR_PTR(-EIDRM); 1109 goto out_unlock0; 1110 } 1111 1112 msg = find_msg(msq, &msgtyp, mode); 1113 if (!IS_ERR(msg)) { 1114 /* 1115 * Found a suitable message. 1116 * Unlink it from the queue. 1117 */ 1118 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { 1119 msg = ERR_PTR(-E2BIG); 1120 goto out_unlock0; 1121 } 1122 /* 1123 * If we are copying, then do not unlink message and do 1124 * not update queue parameters. 1125 */ 1126 if (msgflg & MSG_COPY) { 1127 msg = copy_msg(msg, copy); 1128 goto out_unlock0; 1129 } 1130 1131 list_del(&msg->m_list); 1132 msq->q_qnum--; 1133 msq->q_rtime = ktime_get_real_seconds(); 1134 ipc_update_pid(&msq->q_lrpid, task_tgid(current)); 1135 msq->q_cbytes -= msg->m_ts; 1136 atomic_sub(msg->m_ts, &ns->msg_bytes); 1137 atomic_dec(&ns->msg_hdrs); 1138 ss_wakeup(msq, &wake_q, false); 1139 1140 goto out_unlock0; 1141 } 1142 1143 /* No message waiting. Wait for a message */ 1144 if (msgflg & IPC_NOWAIT) { 1145 msg = ERR_PTR(-ENOMSG); 1146 goto out_unlock0; 1147 } 1148 1149 list_add_tail(&msr_d.r_list, &msq->q_receivers); 1150 msr_d.r_tsk = current; 1151 msr_d.r_msgtype = msgtyp; 1152 msr_d.r_mode = mode; 1153 if (msgflg & MSG_NOERROR) 1154 msr_d.r_maxsize = INT_MAX; 1155 else 1156 msr_d.r_maxsize = bufsz; 1157 msr_d.r_msg = ERR_PTR(-EAGAIN); 1158 __set_current_state(TASK_INTERRUPTIBLE); 1159 1160 ipc_unlock_object(&msq->q_perm); 1161 rcu_read_unlock(); 1162 schedule(); 1163 1164 /* 1165 * Lockless receive, part 1: 1166 * We don't hold a reference to the queue and getting a 1167 * reference would defeat the idea of a lockless operation, 1168 * thus the code relies on rcu to guarantee the existence of 1169 * msq: 1170 * Prior to destruction, expunge_all(-EIRDM) changes r_msg. 1171 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. 1172 */ 1173 rcu_read_lock(); 1174 1175 /* 1176 * Lockless receive, part 2: 1177 * The work in pipelined_send() and expunge_all(): 1178 * - Set pointer to message 1179 * - Queue the receiver task for later wakeup 1180 * - Wake up the process after the lock is dropped. 1181 * 1182 * Should the process wake up before this wakeup (due to a 1183 * signal) it will either see the message and continue ... 1184 */ 1185 msg = READ_ONCE(msr_d.r_msg); 1186 if (msg != ERR_PTR(-EAGAIN)) 1187 goto out_unlock1; 1188 1189 /* 1190 * ... or see -EAGAIN, acquire the lock to check the message 1191 * again. 1192 */ 1193 ipc_lock_object(&msq->q_perm); 1194 1195 msg = msr_d.r_msg; 1196 if (msg != ERR_PTR(-EAGAIN)) 1197 goto out_unlock0; 1198 1199 list_del(&msr_d.r_list); 1200 if (signal_pending(current)) { 1201 msg = ERR_PTR(-ERESTARTNOHAND); 1202 goto out_unlock0; 1203 } 1204 1205 ipc_unlock_object(&msq->q_perm); 1206 } 1207 1208 out_unlock0: 1209 ipc_unlock_object(&msq->q_perm); 1210 wake_up_q(&wake_q); 1211 out_unlock1: 1212 rcu_read_unlock(); 1213 if (IS_ERR(msg)) { 1214 free_copy(copy); 1215 return PTR_ERR(msg); 1216 } 1217 1218 bufsz = msg_handler(buf, msg, bufsz); 1219 free_msg(msg); 1220 1221 return bufsz; 1222 } 1223 1224 long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz, 1225 long msgtyp, int msgflg) 1226 { 1227 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill); 1228 } 1229 1230 SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, 1231 long, msgtyp, int, msgflg) 1232 { 1233 return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg); 1234 } 1235 1236 #ifdef CONFIG_COMPAT 1237 static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) 1238 { 1239 struct compat_msgbuf __user *msgp = dest; 1240 size_t msgsz; 1241 1242 if (put_user(msg->m_type, &msgp->mtype)) 1243 return -EFAULT; 1244 1245 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; 1246 if (store_msg(msgp->mtext, msg, msgsz)) 1247 return -EFAULT; 1248 return msgsz; 1249 } 1250 1251 long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, 1252 compat_long_t msgtyp, int msgflg) 1253 { 1254 return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp, 1255 msgflg, compat_do_msg_fill); 1256 } 1257 1258 COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp, 1259 compat_ssize_t, msgsz, compat_long_t, msgtyp, 1260 int, msgflg) 1261 { 1262 return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg); 1263 } 1264 #endif 1265 1266 void msg_init_ns(struct ipc_namespace *ns) 1267 { 1268 ns->msg_ctlmax = MSGMAX; 1269 ns->msg_ctlmnb = MSGMNB; 1270 ns->msg_ctlmni = MSGMNI; 1271 1272 atomic_set(&ns->msg_bytes, 0); 1273 atomic_set(&ns->msg_hdrs, 0); 1274 ipc_init_ids(&ns->ids[IPC_MSG_IDS]); 1275 } 1276 1277 #ifdef CONFIG_IPC_NS 1278 void msg_exit_ns(struct ipc_namespace *ns) 1279 { 1280 free_ipcs(ns, &msg_ids(ns), freeque); 1281 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr); 1282 rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht); 1283 } 1284 #endif 1285 1286 #ifdef CONFIG_PROC_FS 1287 static int sysvipc_msg_proc_show(struct seq_file *s, void *it) 1288 { 1289 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s); 1290 struct user_namespace *user_ns = seq_user_ns(s); 1291 struct kern_ipc_perm *ipcp = it; 1292 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); 1293 1294 seq_printf(s, 1295 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n", 1296 msq->q_perm.key, 1297 msq->q_perm.id, 1298 msq->q_perm.mode, 1299 msq->q_cbytes, 1300 msq->q_qnum, 1301 pid_nr_ns(msq->q_lspid, pid_ns), 1302 pid_nr_ns(msq->q_lrpid, pid_ns), 1303 from_kuid_munged(user_ns, msq->q_perm.uid), 1304 from_kgid_munged(user_ns, msq->q_perm.gid), 1305 from_kuid_munged(user_ns, msq->q_perm.cuid), 1306 from_kgid_munged(user_ns, msq->q_perm.cgid), 1307 msq->q_stime, 1308 msq->q_rtime, 1309 msq->q_ctime); 1310 1311 return 0; 1312 } 1313 #endif 1314 1315 void __init msg_init(void) 1316 { 1317 msg_init_ns(&init_ipc_ns); 1318 1319 ipc_init_proc_interface("sysvipc/msg", 1320 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", 1321 IPC_MSG_IDS, sysvipc_msg_proc_show); 1322 } 1323