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