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 call_rcu(&msq->q_perm.rcu, 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_pre_down_nolock(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_id; 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_id = ipc_get_maxid(&msg_ids(ns)); 487 up_read(&msg_ids(ns).rwsem); 488 return (max_id < 0) ? 0 : max_id; 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 id = 0; 496 int err; 497 498 memset(p, 0, sizeof(*p)); 499 500 rcu_read_lock(); 501 if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) { 502 msq = msq_obtain_object(ns, msqid); 503 if (IS_ERR(msq)) { 504 err = PTR_ERR(msq); 505 goto out_unlock; 506 } 507 id = msq->q_perm.id; 508 } else { /* IPC_STAT */ 509 msq = msq_obtain_object_check(ns, msqid); 510 if (IS_ERR(msq)) { 511 err = PTR_ERR(msq); 512 goto out_unlock; 513 } 514 } 515 516 /* see comment for SHM_STAT_ANY */ 517 if (cmd == MSG_STAT_ANY) 518 audit_ipc_obj(&msq->q_perm); 519 else { 520 err = -EACCES; 521 if (ipcperms(ns, &msq->q_perm, S_IRUGO)) 522 goto out_unlock; 523 } 524 525 err = security_msg_queue_msgctl(&msq->q_perm, cmd); 526 if (err) 527 goto out_unlock; 528 529 ipc_lock_object(&msq->q_perm); 530 531 if (!ipc_valid_object(&msq->q_perm)) { 532 ipc_unlock_object(&msq->q_perm); 533 err = -EIDRM; 534 goto out_unlock; 535 } 536 537 kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm); 538 p->msg_stime = msq->q_stime; 539 p->msg_rtime = msq->q_rtime; 540 p->msg_ctime = msq->q_ctime; 541 #ifndef CONFIG_64BIT 542 p->msg_stime_high = msq->q_stime >> 32; 543 p->msg_rtime_high = msq->q_rtime >> 32; 544 p->msg_ctime_high = msq->q_ctime >> 32; 545 #endif 546 p->msg_cbytes = msq->q_cbytes; 547 p->msg_qnum = msq->q_qnum; 548 p->msg_qbytes = msq->q_qbytes; 549 p->msg_lspid = pid_vnr(msq->q_lspid); 550 p->msg_lrpid = pid_vnr(msq->q_lrpid); 551 552 ipc_unlock_object(&msq->q_perm); 553 rcu_read_unlock(); 554 return id; 555 556 out_unlock: 557 rcu_read_unlock(); 558 return err; 559 } 560 561 long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) 562 { 563 int version; 564 struct ipc_namespace *ns; 565 struct msqid64_ds msqid64; 566 int err; 567 568 if (msqid < 0 || cmd < 0) 569 return -EINVAL; 570 571 version = ipc_parse_version(&cmd); 572 ns = current->nsproxy->ipc_ns; 573 574 switch (cmd) { 575 case IPC_INFO: 576 case MSG_INFO: { 577 struct msginfo msginfo; 578 err = msgctl_info(ns, msqid, cmd, &msginfo); 579 if (err < 0) 580 return err; 581 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) 582 err = -EFAULT; 583 return err; 584 } 585 case MSG_STAT: /* msqid is an index rather than a msg queue id */ 586 case MSG_STAT_ANY: 587 case IPC_STAT: 588 err = msgctl_stat(ns, msqid, cmd, &msqid64); 589 if (err < 0) 590 return err; 591 if (copy_msqid_to_user(buf, &msqid64, version)) 592 err = -EFAULT; 593 return err; 594 case IPC_SET: 595 if (copy_msqid_from_user(&msqid64, buf, version)) 596 return -EFAULT; 597 /* fallthru */ 598 case IPC_RMID: 599 return msgctl_down(ns, msqid, cmd, &msqid64); 600 default: 601 return -EINVAL; 602 } 603 } 604 605 SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) 606 { 607 return ksys_msgctl(msqid, cmd, buf); 608 } 609 610 #ifdef CONFIG_COMPAT 611 612 struct compat_msqid_ds { 613 struct compat_ipc_perm msg_perm; 614 compat_uptr_t msg_first; 615 compat_uptr_t msg_last; 616 compat_time_t msg_stime; 617 compat_time_t msg_rtime; 618 compat_time_t msg_ctime; 619 compat_ulong_t msg_lcbytes; 620 compat_ulong_t msg_lqbytes; 621 unsigned short msg_cbytes; 622 unsigned short msg_qnum; 623 unsigned short msg_qbytes; 624 compat_ipc_pid_t msg_lspid; 625 compat_ipc_pid_t msg_lrpid; 626 }; 627 628 static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf, 629 int version) 630 { 631 memset(out, 0, sizeof(*out)); 632 if (version == IPC_64) { 633 struct compat_msqid64_ds __user *p = buf; 634 if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm)) 635 return -EFAULT; 636 if (get_user(out->msg_qbytes, &p->msg_qbytes)) 637 return -EFAULT; 638 } else { 639 struct compat_msqid_ds __user *p = buf; 640 if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm)) 641 return -EFAULT; 642 if (get_user(out->msg_qbytes, &p->msg_qbytes)) 643 return -EFAULT; 644 } 645 return 0; 646 } 647 648 static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in, 649 int version) 650 { 651 if (version == IPC_64) { 652 struct compat_msqid64_ds v; 653 memset(&v, 0, sizeof(v)); 654 to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm); 655 v.msg_stime = lower_32_bits(in->msg_stime); 656 v.msg_stime_high = upper_32_bits(in->msg_stime); 657 v.msg_rtime = lower_32_bits(in->msg_rtime); 658 v.msg_rtime_high = upper_32_bits(in->msg_rtime); 659 v.msg_ctime = lower_32_bits(in->msg_ctime); 660 v.msg_ctime_high = upper_32_bits(in->msg_ctime); 661 v.msg_cbytes = in->msg_cbytes; 662 v.msg_qnum = in->msg_qnum; 663 v.msg_qbytes = in->msg_qbytes; 664 v.msg_lspid = in->msg_lspid; 665 v.msg_lrpid = in->msg_lrpid; 666 return copy_to_user(buf, &v, sizeof(v)); 667 } else { 668 struct compat_msqid_ds v; 669 memset(&v, 0, sizeof(v)); 670 to_compat_ipc_perm(&v.msg_perm, &in->msg_perm); 671 v.msg_stime = in->msg_stime; 672 v.msg_rtime = in->msg_rtime; 673 v.msg_ctime = in->msg_ctime; 674 v.msg_cbytes = in->msg_cbytes; 675 v.msg_qnum = in->msg_qnum; 676 v.msg_qbytes = in->msg_qbytes; 677 v.msg_lspid = in->msg_lspid; 678 v.msg_lrpid = in->msg_lrpid; 679 return copy_to_user(buf, &v, sizeof(v)); 680 } 681 } 682 683 long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr) 684 { 685 struct ipc_namespace *ns; 686 int err; 687 struct msqid64_ds msqid64; 688 int version = compat_ipc_parse_version(&cmd); 689 690 ns = current->nsproxy->ipc_ns; 691 692 if (msqid < 0 || cmd < 0) 693 return -EINVAL; 694 695 switch (cmd & (~IPC_64)) { 696 case IPC_INFO: 697 case MSG_INFO: { 698 struct msginfo msginfo; 699 err = msgctl_info(ns, msqid, cmd, &msginfo); 700 if (err < 0) 701 return err; 702 if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo))) 703 err = -EFAULT; 704 return err; 705 } 706 case IPC_STAT: 707 case MSG_STAT: 708 case MSG_STAT_ANY: 709 err = msgctl_stat(ns, msqid, cmd, &msqid64); 710 if (err < 0) 711 return err; 712 if (copy_compat_msqid_to_user(uptr, &msqid64, version)) 713 err = -EFAULT; 714 return err; 715 case IPC_SET: 716 if (copy_compat_msqid_from_user(&msqid64, uptr, version)) 717 return -EFAULT; 718 /* fallthru */ 719 case IPC_RMID: 720 return msgctl_down(ns, msqid, cmd, &msqid64); 721 default: 722 return -EINVAL; 723 } 724 } 725 726 COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr) 727 { 728 return compat_ksys_msgctl(msqid, cmd, uptr); 729 } 730 #endif 731 732 static int testmsg(struct msg_msg *msg, long type, int mode) 733 { 734 switch (mode) { 735 case SEARCH_ANY: 736 case SEARCH_NUMBER: 737 return 1; 738 case SEARCH_LESSEQUAL: 739 if (msg->m_type <= type) 740 return 1; 741 break; 742 case SEARCH_EQUAL: 743 if (msg->m_type == type) 744 return 1; 745 break; 746 case SEARCH_NOTEQUAL: 747 if (msg->m_type != type) 748 return 1; 749 break; 750 } 751 return 0; 752 } 753 754 static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg, 755 struct wake_q_head *wake_q) 756 { 757 struct msg_receiver *msr, *t; 758 759 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { 760 if (testmsg(msg, msr->r_msgtype, msr->r_mode) && 761 !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk, 762 msr->r_msgtype, msr->r_mode)) { 763 764 list_del(&msr->r_list); 765 if (msr->r_maxsize < msg->m_ts) { 766 wake_q_add(wake_q, msr->r_tsk); 767 WRITE_ONCE(msr->r_msg, ERR_PTR(-E2BIG)); 768 } else { 769 ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk)); 770 msq->q_rtime = ktime_get_real_seconds(); 771 772 wake_q_add(wake_q, msr->r_tsk); 773 WRITE_ONCE(msr->r_msg, msg); 774 return 1; 775 } 776 } 777 } 778 779 return 0; 780 } 781 782 static long do_msgsnd(int msqid, long mtype, void __user *mtext, 783 size_t msgsz, int msgflg) 784 { 785 struct msg_queue *msq; 786 struct msg_msg *msg; 787 int err; 788 struct ipc_namespace *ns; 789 DEFINE_WAKE_Q(wake_q); 790 791 ns = current->nsproxy->ipc_ns; 792 793 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0) 794 return -EINVAL; 795 if (mtype < 1) 796 return -EINVAL; 797 798 msg = load_msg(mtext, msgsz); 799 if (IS_ERR(msg)) 800 return PTR_ERR(msg); 801 802 msg->m_type = mtype; 803 msg->m_ts = msgsz; 804 805 rcu_read_lock(); 806 msq = msq_obtain_object_check(ns, msqid); 807 if (IS_ERR(msq)) { 808 err = PTR_ERR(msq); 809 goto out_unlock1; 810 } 811 812 ipc_lock_object(&msq->q_perm); 813 814 for (;;) { 815 struct msg_sender s; 816 817 err = -EACCES; 818 if (ipcperms(ns, &msq->q_perm, S_IWUGO)) 819 goto out_unlock0; 820 821 /* raced with RMID? */ 822 if (!ipc_valid_object(&msq->q_perm)) { 823 err = -EIDRM; 824 goto out_unlock0; 825 } 826 827 err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg); 828 if (err) 829 goto out_unlock0; 830 831 if (msg_fits_inqueue(msq, msgsz)) 832 break; 833 834 /* queue full, wait: */ 835 if (msgflg & IPC_NOWAIT) { 836 err = -EAGAIN; 837 goto out_unlock0; 838 } 839 840 /* enqueue the sender and prepare to block */ 841 ss_add(msq, &s, msgsz); 842 843 if (!ipc_rcu_getref(&msq->q_perm)) { 844 err = -EIDRM; 845 goto out_unlock0; 846 } 847 848 ipc_unlock_object(&msq->q_perm); 849 rcu_read_unlock(); 850 schedule(); 851 852 rcu_read_lock(); 853 ipc_lock_object(&msq->q_perm); 854 855 ipc_rcu_putref(&msq->q_perm, msg_rcu_free); 856 /* raced with RMID? */ 857 if (!ipc_valid_object(&msq->q_perm)) { 858 err = -EIDRM; 859 goto out_unlock0; 860 } 861 ss_del(&s); 862 863 if (signal_pending(current)) { 864 err = -ERESTARTNOHAND; 865 goto out_unlock0; 866 } 867 868 } 869 870 ipc_update_pid(&msq->q_lspid, task_tgid(current)); 871 msq->q_stime = ktime_get_real_seconds(); 872 873 if (!pipelined_send(msq, msg, &wake_q)) { 874 /* no one is waiting for this message, enqueue it */ 875 list_add_tail(&msg->m_list, &msq->q_messages); 876 msq->q_cbytes += msgsz; 877 msq->q_qnum++; 878 atomic_add(msgsz, &ns->msg_bytes); 879 atomic_inc(&ns->msg_hdrs); 880 } 881 882 err = 0; 883 msg = NULL; 884 885 out_unlock0: 886 ipc_unlock_object(&msq->q_perm); 887 wake_up_q(&wake_q); 888 out_unlock1: 889 rcu_read_unlock(); 890 if (msg != NULL) 891 free_msg(msg); 892 return err; 893 } 894 895 long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, 896 int msgflg) 897 { 898 long mtype; 899 900 if (get_user(mtype, &msgp->mtype)) 901 return -EFAULT; 902 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg); 903 } 904 905 SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, 906 int, msgflg) 907 { 908 return ksys_msgsnd(msqid, msgp, msgsz, msgflg); 909 } 910 911 #ifdef CONFIG_COMPAT 912 913 struct compat_msgbuf { 914 compat_long_t mtype; 915 char mtext[1]; 916 }; 917 918 long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp, 919 compat_ssize_t msgsz, int msgflg) 920 { 921 struct compat_msgbuf __user *up = compat_ptr(msgp); 922 compat_long_t mtype; 923 924 if (get_user(mtype, &up->mtype)) 925 return -EFAULT; 926 return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg); 927 } 928 929 COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp, 930 compat_ssize_t, msgsz, int, msgflg) 931 { 932 return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg); 933 } 934 #endif 935 936 static inline int convert_mode(long *msgtyp, int msgflg) 937 { 938 if (msgflg & MSG_COPY) 939 return SEARCH_NUMBER; 940 /* 941 * find message of correct type. 942 * msgtyp = 0 => get first. 943 * msgtyp > 0 => get first message of matching type. 944 * msgtyp < 0 => get message with least type must be < abs(msgtype). 945 */ 946 if (*msgtyp == 0) 947 return SEARCH_ANY; 948 if (*msgtyp < 0) { 949 if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */ 950 *msgtyp = LONG_MAX; 951 else 952 *msgtyp = -*msgtyp; 953 return SEARCH_LESSEQUAL; 954 } 955 if (msgflg & MSG_EXCEPT) 956 return SEARCH_NOTEQUAL; 957 return SEARCH_EQUAL; 958 } 959 960 static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) 961 { 962 struct msgbuf __user *msgp = dest; 963 size_t msgsz; 964 965 if (put_user(msg->m_type, &msgp->mtype)) 966 return -EFAULT; 967 968 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; 969 if (store_msg(msgp->mtext, msg, msgsz)) 970 return -EFAULT; 971 return msgsz; 972 } 973 974 #ifdef CONFIG_CHECKPOINT_RESTORE 975 /* 976 * This function creates new kernel message structure, large enough to store 977 * bufsz message bytes. 978 */ 979 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) 980 { 981 struct msg_msg *copy; 982 983 /* 984 * Create dummy message to copy real message to. 985 */ 986 copy = load_msg(buf, bufsz); 987 if (!IS_ERR(copy)) 988 copy->m_ts = bufsz; 989 return copy; 990 } 991 992 static inline void free_copy(struct msg_msg *copy) 993 { 994 if (copy) 995 free_msg(copy); 996 } 997 #else 998 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) 999 { 1000 return ERR_PTR(-ENOSYS); 1001 } 1002 1003 static inline void free_copy(struct msg_msg *copy) 1004 { 1005 } 1006 #endif 1007 1008 static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode) 1009 { 1010 struct msg_msg *msg, *found = NULL; 1011 long count = 0; 1012 1013 list_for_each_entry(msg, &msq->q_messages, m_list) { 1014 if (testmsg(msg, *msgtyp, mode) && 1015 !security_msg_queue_msgrcv(&msq->q_perm, msg, current, 1016 *msgtyp, mode)) { 1017 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) { 1018 *msgtyp = msg->m_type - 1; 1019 found = msg; 1020 } else if (mode == SEARCH_NUMBER) { 1021 if (*msgtyp == count) 1022 return msg; 1023 } else 1024 return msg; 1025 count++; 1026 } 1027 } 1028 1029 return found ?: ERR_PTR(-EAGAIN); 1030 } 1031 1032 static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg, 1033 long (*msg_handler)(void __user *, struct msg_msg *, size_t)) 1034 { 1035 int mode; 1036 struct msg_queue *msq; 1037 struct ipc_namespace *ns; 1038 struct msg_msg *msg, *copy = NULL; 1039 DEFINE_WAKE_Q(wake_q); 1040 1041 ns = current->nsproxy->ipc_ns; 1042 1043 if (msqid < 0 || (long) bufsz < 0) 1044 return -EINVAL; 1045 1046 if (msgflg & MSG_COPY) { 1047 if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT)) 1048 return -EINVAL; 1049 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); 1050 if (IS_ERR(copy)) 1051 return PTR_ERR(copy); 1052 } 1053 mode = convert_mode(&msgtyp, msgflg); 1054 1055 rcu_read_lock(); 1056 msq = msq_obtain_object_check(ns, msqid); 1057 if (IS_ERR(msq)) { 1058 rcu_read_unlock(); 1059 free_copy(copy); 1060 return PTR_ERR(msq); 1061 } 1062 1063 for (;;) { 1064 struct msg_receiver msr_d; 1065 1066 msg = ERR_PTR(-EACCES); 1067 if (ipcperms(ns, &msq->q_perm, S_IRUGO)) 1068 goto out_unlock1; 1069 1070 ipc_lock_object(&msq->q_perm); 1071 1072 /* raced with RMID? */ 1073 if (!ipc_valid_object(&msq->q_perm)) { 1074 msg = ERR_PTR(-EIDRM); 1075 goto out_unlock0; 1076 } 1077 1078 msg = find_msg(msq, &msgtyp, mode); 1079 if (!IS_ERR(msg)) { 1080 /* 1081 * Found a suitable message. 1082 * Unlink it from the queue. 1083 */ 1084 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { 1085 msg = ERR_PTR(-E2BIG); 1086 goto out_unlock0; 1087 } 1088 /* 1089 * If we are copying, then do not unlink message and do 1090 * not update queue parameters. 1091 */ 1092 if (msgflg & MSG_COPY) { 1093 msg = copy_msg(msg, copy); 1094 goto out_unlock0; 1095 } 1096 1097 list_del(&msg->m_list); 1098 msq->q_qnum--; 1099 msq->q_rtime = ktime_get_real_seconds(); 1100 ipc_update_pid(&msq->q_lrpid, task_tgid(current)); 1101 msq->q_cbytes -= msg->m_ts; 1102 atomic_sub(msg->m_ts, &ns->msg_bytes); 1103 atomic_dec(&ns->msg_hdrs); 1104 ss_wakeup(msq, &wake_q, false); 1105 1106 goto out_unlock0; 1107 } 1108 1109 /* No message waiting. Wait for a message */ 1110 if (msgflg & IPC_NOWAIT) { 1111 msg = ERR_PTR(-ENOMSG); 1112 goto out_unlock0; 1113 } 1114 1115 list_add_tail(&msr_d.r_list, &msq->q_receivers); 1116 msr_d.r_tsk = current; 1117 msr_d.r_msgtype = msgtyp; 1118 msr_d.r_mode = mode; 1119 if (msgflg & MSG_NOERROR) 1120 msr_d.r_maxsize = INT_MAX; 1121 else 1122 msr_d.r_maxsize = bufsz; 1123 msr_d.r_msg = ERR_PTR(-EAGAIN); 1124 __set_current_state(TASK_INTERRUPTIBLE); 1125 1126 ipc_unlock_object(&msq->q_perm); 1127 rcu_read_unlock(); 1128 schedule(); 1129 1130 /* 1131 * Lockless receive, part 1: 1132 * We don't hold a reference to the queue and getting a 1133 * reference would defeat the idea of a lockless operation, 1134 * thus the code relies on rcu to guarantee the existence of 1135 * msq: 1136 * Prior to destruction, expunge_all(-EIRDM) changes r_msg. 1137 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. 1138 */ 1139 rcu_read_lock(); 1140 1141 /* 1142 * Lockless receive, part 2: 1143 * The work in pipelined_send() and expunge_all(): 1144 * - Set pointer to message 1145 * - Queue the receiver task for later wakeup 1146 * - Wake up the process after the lock is dropped. 1147 * 1148 * Should the process wake up before this wakeup (due to a 1149 * signal) it will either see the message and continue ... 1150 */ 1151 msg = READ_ONCE(msr_d.r_msg); 1152 if (msg != ERR_PTR(-EAGAIN)) 1153 goto out_unlock1; 1154 1155 /* 1156 * ... or see -EAGAIN, acquire the lock to check the message 1157 * again. 1158 */ 1159 ipc_lock_object(&msq->q_perm); 1160 1161 msg = msr_d.r_msg; 1162 if (msg != ERR_PTR(-EAGAIN)) 1163 goto out_unlock0; 1164 1165 list_del(&msr_d.r_list); 1166 if (signal_pending(current)) { 1167 msg = ERR_PTR(-ERESTARTNOHAND); 1168 goto out_unlock0; 1169 } 1170 1171 ipc_unlock_object(&msq->q_perm); 1172 } 1173 1174 out_unlock0: 1175 ipc_unlock_object(&msq->q_perm); 1176 wake_up_q(&wake_q); 1177 out_unlock1: 1178 rcu_read_unlock(); 1179 if (IS_ERR(msg)) { 1180 free_copy(copy); 1181 return PTR_ERR(msg); 1182 } 1183 1184 bufsz = msg_handler(buf, msg, bufsz); 1185 free_msg(msg); 1186 1187 return bufsz; 1188 } 1189 1190 long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz, 1191 long msgtyp, int msgflg) 1192 { 1193 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill); 1194 } 1195 1196 SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, 1197 long, msgtyp, int, msgflg) 1198 { 1199 return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg); 1200 } 1201 1202 #ifdef CONFIG_COMPAT 1203 static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) 1204 { 1205 struct compat_msgbuf __user *msgp = dest; 1206 size_t msgsz; 1207 1208 if (put_user(msg->m_type, &msgp->mtype)) 1209 return -EFAULT; 1210 1211 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; 1212 if (store_msg(msgp->mtext, msg, msgsz)) 1213 return -EFAULT; 1214 return msgsz; 1215 } 1216 1217 long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, 1218 compat_long_t msgtyp, int msgflg) 1219 { 1220 return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp, 1221 msgflg, compat_do_msg_fill); 1222 } 1223 1224 COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp, 1225 compat_ssize_t, msgsz, compat_long_t, msgtyp, 1226 int, msgflg) 1227 { 1228 return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg); 1229 } 1230 #endif 1231 1232 int msg_init_ns(struct ipc_namespace *ns) 1233 { 1234 ns->msg_ctlmax = MSGMAX; 1235 ns->msg_ctlmnb = MSGMNB; 1236 ns->msg_ctlmni = MSGMNI; 1237 1238 atomic_set(&ns->msg_bytes, 0); 1239 atomic_set(&ns->msg_hdrs, 0); 1240 return ipc_init_ids(&ns->ids[IPC_MSG_IDS]); 1241 } 1242 1243 #ifdef CONFIG_IPC_NS 1244 void msg_exit_ns(struct ipc_namespace *ns) 1245 { 1246 free_ipcs(ns, &msg_ids(ns), freeque); 1247 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr); 1248 rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht); 1249 } 1250 #endif 1251 1252 #ifdef CONFIG_PROC_FS 1253 static int sysvipc_msg_proc_show(struct seq_file *s, void *it) 1254 { 1255 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s); 1256 struct user_namespace *user_ns = seq_user_ns(s); 1257 struct kern_ipc_perm *ipcp = it; 1258 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); 1259 1260 seq_printf(s, 1261 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n", 1262 msq->q_perm.key, 1263 msq->q_perm.id, 1264 msq->q_perm.mode, 1265 msq->q_cbytes, 1266 msq->q_qnum, 1267 pid_nr_ns(msq->q_lspid, pid_ns), 1268 pid_nr_ns(msq->q_lrpid, pid_ns), 1269 from_kuid_munged(user_ns, msq->q_perm.uid), 1270 from_kgid_munged(user_ns, msq->q_perm.gid), 1271 from_kuid_munged(user_ns, msq->q_perm.cuid), 1272 from_kgid_munged(user_ns, msq->q_perm.cgid), 1273 msq->q_stime, 1274 msq->q_rtime, 1275 msq->q_ctime); 1276 1277 return 0; 1278 } 1279 #endif 1280 1281 int __init msg_init(void) 1282 { 1283 const int err = msg_init_ns(&init_ipc_ns); 1284 1285 ipc_init_proc_interface("sysvipc/msg", 1286 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", 1287 IPC_MSG_IDS, sysvipc_msg_proc_show); 1288 return err; 1289 } 1290