| 1 | |
| 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 <[email protected]>
|
| 13 | *
|
| 14 | * mostly rewritten, threaded and wake-one semantics added
|
| 15 | * MSGMAX limit removed, sysctl's added
|
| 16 | * (c) 1999 Manfred Spraul <[email protected]>
|
| 17 | *
|
| 18 | * support for audit of ipc object properties and permission changes
|
| 19 | * Dustin Kirkland <[email protected]>
|
| 20 | *
|
| 21 | * namespaces support
|
| 22 | * OpenVZ, SWsoft Inc.
|
| 23 | * Pavel Emelianov <[email protected]>
|
| 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 |
|
| 47 | struct msg_queue {
|
| 48 | struct kern_ipc_perm q_perm;
|
| 49 | time64_t q_stime;
|
| 50 | time64_t q_rtime;
|
| 51 | time64_t q_ctime;
|
| 52 | unsigned long q_cbytes;
|
| 53 | unsigned long q_qnum;
|
| 54 | unsigned long q_qbytes;
|
| 55 | struct pid *q_lspid;
|
| 56 | struct pid *q_lrpid;
|
| 57 |
|
| 58 | struct list_head q_messages;
|
| 59 | struct list_head q_receivers;
|
| 60 | struct list_head q_senders;
|
| 61 | } __randomize_layout;
|
| 62 |
|
| 63 |
|
| 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 |
|
| 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 |
|
| 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 |
|
| 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 {
|
| 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 |
|
| 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:
|
| 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 |
|
| 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 |
|
| 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 |
|
| 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 |
|
| 826 | if (msgflg & IPC_NOWAIT) {
|
| 827 | err = -EAGAIN;
|
| 828 | goto out_unlock0;
|
| 829 | }
|
| 830 |
|
| 831 |
|
| 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 |
|
| 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 |
|
| 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)
|
| 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 |
|
| 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 |
|
| 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 | }
|