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1/*
2 * POSIX message queues filesystem for Linux.
3 *
4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
5 * Michal Wronski (michal.wronski@gmail.com)
6 *
7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
8 * Lockless receive & send, fd based notify:
9 * Manfred Spraul (manfred@colorfullife.com)
10 *
11 * Audit: George Wilson (ltcgcw@us.ibm.com)
12 *
13 * This file is released under the GPL.
14 */
15
16#include <linux/capability.h>
17#include <linux/init.h>
18#include <linux/pagemap.h>
19#include <linux/file.h>
20#include <linux/mount.h>
21#include <linux/namei.h>
22#include <linux/sysctl.h>
23#include <linux/poll.h>
24#include <linux/mqueue.h>
25#include <linux/msg.h>
26#include <linux/skbuff.h>
27#include <linux/vmalloc.h>
28#include <linux/netlink.h>
29#include <linux/syscalls.h>
30#include <linux/audit.h>
31#include <linux/signal.h>
32#include <linux/mutex.h>
33#include <linux/nsproxy.h>
34#include <linux/pid.h>
35#include <linux/ipc_namespace.h>
36#include <linux/user_namespace.h>
37#include <linux/slab.h>
38
39#include <net/sock.h>
40#include "util.h"
41
42#define MQUEUE_MAGIC 0x19800202
43#define DIRENT_SIZE 20
44#define FILENT_SIZE 80
45
46#define SEND 0
47#define RECV 1
48
49#define STATE_NONE 0
50#define STATE_READY 1
51
52struct posix_msg_tree_node {
53 struct rb_node rb_node;
54 struct list_head msg_list;
55 int priority;
56};
57
58struct ext_wait_queue { /* queue of sleeping tasks */
59 struct task_struct *task;
60 struct list_head list;
61 struct msg_msg *msg; /* ptr of loaded message */
62 int state; /* one of STATE_* values */
63};
64
65struct mqueue_inode_info {
66 spinlock_t lock;
67 struct inode vfs_inode;
68 wait_queue_head_t wait_q;
69
70 struct rb_root msg_tree;
71 struct posix_msg_tree_node *node_cache;
72 struct mq_attr attr;
73
74 struct sigevent notify;
75 struct pid *notify_owner;
76 struct user_namespace *notify_user_ns;
77 struct user_struct *user; /* user who created, for accounting */
78 struct sock *notify_sock;
79 struct sk_buff *notify_cookie;
80
81 /* for tasks waiting for free space and messages, respectively */
82 struct ext_wait_queue e_wait_q[2];
83
84 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
85};
86
87static const struct inode_operations mqueue_dir_inode_operations;
88static const struct file_operations mqueue_file_operations;
89static const struct super_operations mqueue_super_ops;
90static void remove_notification(struct mqueue_inode_info *info);
91
92static struct kmem_cache *mqueue_inode_cachep;
93
94static struct ctl_table_header *mq_sysctl_table;
95
96static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
97{
98 return container_of(inode, struct mqueue_inode_info, vfs_inode);
99}
100
101/*
102 * This routine should be called with the mq_lock held.
103 */
104static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
105{
106 return get_ipc_ns(inode->i_sb->s_fs_info);
107}
108
109static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
110{
111 struct ipc_namespace *ns;
112
113 spin_lock(&mq_lock);
114 ns = __get_ns_from_inode(inode);
115 spin_unlock(&mq_lock);
116 return ns;
117}
118
119/* Auxiliary functions to manipulate messages' list */
120static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
121{
122 struct rb_node **p, *parent = NULL;
123 struct posix_msg_tree_node *leaf;
124
125 p = &info->msg_tree.rb_node;
126 while (*p) {
127 parent = *p;
128 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
129
130 if (likely(leaf->priority == msg->m_type))
131 goto insert_msg;
132 else if (msg->m_type < leaf->priority)
133 p = &(*p)->rb_left;
134 else
135 p = &(*p)->rb_right;
136 }
137 if (info->node_cache) {
138 leaf = info->node_cache;
139 info->node_cache = NULL;
140 } else {
141 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
142 if (!leaf)
143 return -ENOMEM;
144 INIT_LIST_HEAD(&leaf->msg_list);
145 }
146 leaf->priority = msg->m_type;
147 rb_link_node(&leaf->rb_node, parent, p);
148 rb_insert_color(&leaf->rb_node, &info->msg_tree);
149insert_msg:
150 info->attr.mq_curmsgs++;
151 info->qsize += msg->m_ts;
152 list_add_tail(&msg->m_list, &leaf->msg_list);
153 return 0;
154}
155
156static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
157{
158 struct rb_node **p, *parent = NULL;
159 struct posix_msg_tree_node *leaf;
160 struct msg_msg *msg;
161
162try_again:
163 p = &info->msg_tree.rb_node;
164 while (*p) {
165 parent = *p;
166 /*
167 * During insert, low priorities go to the left and high to the
168 * right. On receive, we want the highest priorities first, so
169 * walk all the way to the right.
170 */
171 p = &(*p)->rb_right;
172 }
173 if (!parent) {
174 if (info->attr.mq_curmsgs) {
175 pr_warn_once("Inconsistency in POSIX message queue, "
176 "no tree element, but supposedly messages "
177 "should exist!\n");
178 info->attr.mq_curmsgs = 0;
179 }
180 return NULL;
181 }
182 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
183 if (unlikely(list_empty(&leaf->msg_list))) {
184 pr_warn_once("Inconsistency in POSIX message queue, "
185 "empty leaf node but we haven't implemented "
186 "lazy leaf delete!\n");
187 rb_erase(&leaf->rb_node, &info->msg_tree);
188 if (info->node_cache) {
189 kfree(leaf);
190 } else {
191 info->node_cache = leaf;
192 }
193 goto try_again;
194 } else {
195 msg = list_first_entry(&leaf->msg_list,
196 struct msg_msg, m_list);
197 list_del(&msg->m_list);
198 if (list_empty(&leaf->msg_list)) {
199 rb_erase(&leaf->rb_node, &info->msg_tree);
200 if (info->node_cache) {
201 kfree(leaf);
202 } else {
203 info->node_cache = leaf;
204 }
205 }
206 }
207 info->attr.mq_curmsgs--;
208 info->qsize -= msg->m_ts;
209 return msg;
210}
211
212static struct inode *mqueue_get_inode(struct super_block *sb,
213 struct ipc_namespace *ipc_ns, umode_t mode,
214 struct mq_attr *attr)
215{
216 struct user_struct *u = current_user();
217 struct inode *inode;
218 int ret = -ENOMEM;
219
220 inode = new_inode(sb);
221 if (!inode)
222 goto err;
223
224 inode->i_ino = get_next_ino();
225 inode->i_mode = mode;
226 inode->i_uid = current_fsuid();
227 inode->i_gid = current_fsgid();
228 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
229
230 if (S_ISREG(mode)) {
231 struct mqueue_inode_info *info;
232 unsigned long mq_bytes, mq_treesize;
233
234 inode->i_fop = &mqueue_file_operations;
235 inode->i_size = FILENT_SIZE;
236 /* mqueue specific info */
237 info = MQUEUE_I(inode);
238 spin_lock_init(&info->lock);
239 init_waitqueue_head(&info->wait_q);
240 INIT_LIST_HEAD(&info->e_wait_q[0].list);
241 INIT_LIST_HEAD(&info->e_wait_q[1].list);
242 info->notify_owner = NULL;
243 info->notify_user_ns = NULL;
244 info->qsize = 0;
245 info->user = NULL; /* set when all is ok */
246 info->msg_tree = RB_ROOT;
247 info->node_cache = NULL;
248 memset(&info->attr, 0, sizeof(info->attr));
249 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
250 ipc_ns->mq_msg_default);
251 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
252 ipc_ns->mq_msgsize_default);
253 if (attr) {
254 info->attr.mq_maxmsg = attr->mq_maxmsg;
255 info->attr.mq_msgsize = attr->mq_msgsize;
256 }
257 /*
258 * We used to allocate a static array of pointers and account
259 * the size of that array as well as one msg_msg struct per
260 * possible message into the queue size. That's no longer
261 * accurate as the queue is now an rbtree and will grow and
262 * shrink depending on usage patterns. We can, however, still
263 * account one msg_msg struct per message, but the nodes are
264 * allocated depending on priority usage, and most programs
265 * only use one, or a handful, of priorities. However, since
266 * this is pinned memory, we need to assume worst case, so
267 * that means the min(mq_maxmsg, max_priorities) * struct
268 * posix_msg_tree_node.
269 */
270 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
271 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
272 sizeof(struct posix_msg_tree_node);
273
274 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
275 info->attr.mq_msgsize);
276
277 spin_lock(&mq_lock);
278 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
279 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
280 spin_unlock(&mq_lock);
281 /* mqueue_evict_inode() releases info->messages */
282 ret = -EMFILE;
283 goto out_inode;
284 }
285 u->mq_bytes += mq_bytes;
286 spin_unlock(&mq_lock);
287
288 /* all is ok */
289 info->user = get_uid(u);
290 } else if (S_ISDIR(mode)) {
291 inc_nlink(inode);
292 /* Some things misbehave if size == 0 on a directory */
293 inode->i_size = 2 * DIRENT_SIZE;
294 inode->i_op = &mqueue_dir_inode_operations;
295 inode->i_fop = &simple_dir_operations;
296 }
297
298 return inode;
299out_inode:
300 iput(inode);
301err:
302 return ERR_PTR(ret);
303}
304
305static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
306{
307 struct inode *inode;
308 struct ipc_namespace *ns = sb->s_fs_info;
309
310 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
311 sb->s_blocksize = PAGE_SIZE;
312 sb->s_blocksize_bits = PAGE_SHIFT;
313 sb->s_magic = MQUEUE_MAGIC;
314 sb->s_op = &mqueue_super_ops;
315
316 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
317 if (IS_ERR(inode))
318 return PTR_ERR(inode);
319
320 sb->s_root = d_make_root(inode);
321 if (!sb->s_root)
322 return -ENOMEM;
323 return 0;
324}
325
326static struct dentry *mqueue_mount(struct file_system_type *fs_type,
327 int flags, const char *dev_name,
328 void *data)
329{
330 struct ipc_namespace *ns;
331 if (flags & MS_KERNMOUNT) {
332 ns = data;
333 data = NULL;
334 } else {
335 ns = current->nsproxy->ipc_ns;
336 }
337 return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super);
338}
339
340static void init_once(void *foo)
341{
342 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
343
344 inode_init_once(&p->vfs_inode);
345}
346
347static struct inode *mqueue_alloc_inode(struct super_block *sb)
348{
349 struct mqueue_inode_info *ei;
350
351 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
352 if (!ei)
353 return NULL;
354 return &ei->vfs_inode;
355}
356
357static void mqueue_i_callback(struct rcu_head *head)
358{
359 struct inode *inode = container_of(head, struct inode, i_rcu);
360 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
361}
362
363static void mqueue_destroy_inode(struct inode *inode)
364{
365 call_rcu(&inode->i_rcu, mqueue_i_callback);
366}
367
368static void mqueue_evict_inode(struct inode *inode)
369{
370 struct mqueue_inode_info *info;
371 struct user_struct *user;
372 unsigned long mq_bytes, mq_treesize;
373 struct ipc_namespace *ipc_ns;
374 struct msg_msg *msg;
375
376 clear_inode(inode);
377
378 if (S_ISDIR(inode->i_mode))
379 return;
380
381 ipc_ns = get_ns_from_inode(inode);
382 info = MQUEUE_I(inode);
383 spin_lock(&info->lock);
384 while ((msg = msg_get(info)) != NULL)
385 free_msg(msg);
386 kfree(info->node_cache);
387 spin_unlock(&info->lock);
388
389 /* Total amount of bytes accounted for the mqueue */
390 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
391 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
392 sizeof(struct posix_msg_tree_node);
393
394 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
395 info->attr.mq_msgsize);
396
397 user = info->user;
398 if (user) {
399 spin_lock(&mq_lock);
400 user->mq_bytes -= mq_bytes;
401 /*
402 * get_ns_from_inode() ensures that the
403 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
404 * to which we now hold a reference, or it is NULL.
405 * We can't put it here under mq_lock, though.
406 */
407 if (ipc_ns)
408 ipc_ns->mq_queues_count--;
409 spin_unlock(&mq_lock);
410 free_uid(user);
411 }
412 if (ipc_ns)
413 put_ipc_ns(ipc_ns);
414}
415
416static int mqueue_create(struct inode *dir, struct dentry *dentry,
417 umode_t mode, bool excl)
418{
419 struct inode *inode;
420 struct mq_attr *attr = dentry->d_fsdata;
421 int error;
422 struct ipc_namespace *ipc_ns;
423
424 spin_lock(&mq_lock);
425 ipc_ns = __get_ns_from_inode(dir);
426 if (!ipc_ns) {
427 error = -EACCES;
428 goto out_unlock;
429 }
430
431 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
432 !capable(CAP_SYS_RESOURCE)) {
433 error = -ENOSPC;
434 goto out_unlock;
435 }
436 ipc_ns->mq_queues_count++;
437 spin_unlock(&mq_lock);
438
439 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
440 if (IS_ERR(inode)) {
441 error = PTR_ERR(inode);
442 spin_lock(&mq_lock);
443 ipc_ns->mq_queues_count--;
444 goto out_unlock;
445 }
446
447 put_ipc_ns(ipc_ns);
448 dir->i_size += DIRENT_SIZE;
449 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
450
451 d_instantiate(dentry, inode);
452 dget(dentry);
453 return 0;
454out_unlock:
455 spin_unlock(&mq_lock);
456 if (ipc_ns)
457 put_ipc_ns(ipc_ns);
458 return error;
459}
460
461static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
462{
463 struct inode *inode = d_inode(dentry);
464
465 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
466 dir->i_size -= DIRENT_SIZE;
467 drop_nlink(inode);
468 dput(dentry);
469 return 0;
470}
471
472/*
473* This is routine for system read from queue file.
474* To avoid mess with doing here some sort of mq_receive we allow
475* to read only queue size & notification info (the only values
476* that are interesting from user point of view and aren't accessible
477* through std routines)
478*/
479static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
480 size_t count, loff_t *off)
481{
482 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
483 char buffer[FILENT_SIZE];
484 ssize_t ret;
485
486 spin_lock(&info->lock);
487 snprintf(buffer, sizeof(buffer),
488 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
489 info->qsize,
490 info->notify_owner ? info->notify.sigev_notify : 0,
491 (info->notify_owner &&
492 info->notify.sigev_notify == SIGEV_SIGNAL) ?
493 info->notify.sigev_signo : 0,
494 pid_vnr(info->notify_owner));
495 spin_unlock(&info->lock);
496 buffer[sizeof(buffer)-1] = '\0';
497
498 ret = simple_read_from_buffer(u_data, count, off, buffer,
499 strlen(buffer));
500 if (ret <= 0)
501 return ret;
502
503 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
504 return ret;
505}
506
507static int mqueue_flush_file(struct file *filp, fl_owner_t id)
508{
509 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
510
511 spin_lock(&info->lock);
512 if (task_tgid(current) == info->notify_owner)
513 remove_notification(info);
514
515 spin_unlock(&info->lock);
516 return 0;
517}
518
519static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
520{
521 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
522 int retval = 0;
523
524 poll_wait(filp, &info->wait_q, poll_tab);
525
526 spin_lock(&info->lock);
527 if (info->attr.mq_curmsgs)
528 retval = POLLIN | POLLRDNORM;
529
530 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
531 retval |= POLLOUT | POLLWRNORM;
532 spin_unlock(&info->lock);
533
534 return retval;
535}
536
537/* Adds current to info->e_wait_q[sr] before element with smaller prio */
538static void wq_add(struct mqueue_inode_info *info, int sr,
539 struct ext_wait_queue *ewp)
540{
541 struct ext_wait_queue *walk;
542
543 ewp->task = current;
544
545 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
546 if (walk->task->static_prio <= current->static_prio) {
547 list_add_tail(&ewp->list, &walk->list);
548 return;
549 }
550 }
551 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
552}
553
554/*
555 * Puts current task to sleep. Caller must hold queue lock. After return
556 * lock isn't held.
557 * sr: SEND or RECV
558 */
559static int wq_sleep(struct mqueue_inode_info *info, int sr,
560 ktime_t *timeout, struct ext_wait_queue *ewp)
561{
562 int retval;
563 signed long time;
564
565 wq_add(info, sr, ewp);
566
567 for (;;) {
568 __set_current_state(TASK_INTERRUPTIBLE);
569
570 spin_unlock(&info->lock);
571 time = schedule_hrtimeout_range_clock(timeout, 0,
572 HRTIMER_MODE_ABS, CLOCK_REALTIME);
573
574 if (ewp->state == STATE_READY) {
575 retval = 0;
576 goto out;
577 }
578 spin_lock(&info->lock);
579 if (ewp->state == STATE_READY) {
580 retval = 0;
581 goto out_unlock;
582 }
583 if (signal_pending(current)) {
584 retval = -ERESTARTSYS;
585 break;
586 }
587 if (time == 0) {
588 retval = -ETIMEDOUT;
589 break;
590 }
591 }
592 list_del(&ewp->list);
593out_unlock:
594 spin_unlock(&info->lock);
595out:
596 return retval;
597}
598
599/*
600 * Returns waiting task that should be serviced first or NULL if none exists
601 */
602static struct ext_wait_queue *wq_get_first_waiter(
603 struct mqueue_inode_info *info, int sr)
604{
605 struct list_head *ptr;
606
607 ptr = info->e_wait_q[sr].list.prev;
608 if (ptr == &info->e_wait_q[sr].list)
609 return NULL;
610 return list_entry(ptr, struct ext_wait_queue, list);
611}
612
613
614static inline void set_cookie(struct sk_buff *skb, char code)
615{
616 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
617}
618
619/*
620 * The next function is only to split too long sys_mq_timedsend
621 */
622static void __do_notify(struct mqueue_inode_info *info)
623{
624 /* notification
625 * invoked when there is registered process and there isn't process
626 * waiting synchronously for message AND state of queue changed from
627 * empty to not empty. Here we are sure that no one is waiting
628 * synchronously. */
629 if (info->notify_owner &&
630 info->attr.mq_curmsgs == 1) {
631 struct siginfo sig_i;
632 switch (info->notify.sigev_notify) {
633 case SIGEV_NONE:
634 break;
635 case SIGEV_SIGNAL:
636 /* sends signal */
637
638 sig_i.si_signo = info->notify.sigev_signo;
639 sig_i.si_errno = 0;
640 sig_i.si_code = SI_MESGQ;
641 sig_i.si_value = info->notify.sigev_value;
642 /* map current pid/uid into info->owner's namespaces */
643 rcu_read_lock();
644 sig_i.si_pid = task_tgid_nr_ns(current,
645 ns_of_pid(info->notify_owner));
646 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
647 rcu_read_unlock();
648
649 kill_pid_info(info->notify.sigev_signo,
650 &sig_i, info->notify_owner);
651 break;
652 case SIGEV_THREAD:
653 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
654 netlink_sendskb(info->notify_sock, info->notify_cookie);
655 break;
656 }
657 /* after notification unregisters process */
658 put_pid(info->notify_owner);
659 put_user_ns(info->notify_user_ns);
660 info->notify_owner = NULL;
661 info->notify_user_ns = NULL;
662 }
663 wake_up(&info->wait_q);
664}
665
666static int prepare_timeout(const struct timespec __user *u_abs_timeout,
667 ktime_t *expires, struct timespec *ts)
668{
669 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
670 return -EFAULT;
671 if (!timespec_valid(ts))
672 return -EINVAL;
673
674 *expires = timespec_to_ktime(*ts);
675 return 0;
676}
677
678static void remove_notification(struct mqueue_inode_info *info)
679{
680 if (info->notify_owner != NULL &&
681 info->notify.sigev_notify == SIGEV_THREAD) {
682 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
683 netlink_sendskb(info->notify_sock, info->notify_cookie);
684 }
685 put_pid(info->notify_owner);
686 put_user_ns(info->notify_user_ns);
687 info->notify_owner = NULL;
688 info->notify_user_ns = NULL;
689}
690
691static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
692{
693 int mq_treesize;
694 unsigned long total_size;
695
696 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
697 return -EINVAL;
698 if (capable(CAP_SYS_RESOURCE)) {
699 if (attr->mq_maxmsg > HARD_MSGMAX ||
700 attr->mq_msgsize > HARD_MSGSIZEMAX)
701 return -EINVAL;
702 } else {
703 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
704 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
705 return -EINVAL;
706 }
707 /* check for overflow */
708 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
709 return -EOVERFLOW;
710 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
711 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
712 sizeof(struct posix_msg_tree_node);
713 total_size = attr->mq_maxmsg * attr->mq_msgsize;
714 if (total_size + mq_treesize < total_size)
715 return -EOVERFLOW;
716 return 0;
717}
718
719/*
720 * Invoked when creating a new queue via sys_mq_open
721 */
722static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
723 struct path *path, int oflag, umode_t mode,
724 struct mq_attr *attr)
725{
726 const struct cred *cred = current_cred();
727 int ret;
728
729 if (attr) {
730 ret = mq_attr_ok(ipc_ns, attr);
731 if (ret)
732 return ERR_PTR(ret);
733 /* store for use during create */
734 path->dentry->d_fsdata = attr;
735 } else {
736 struct mq_attr def_attr;
737
738 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
739 ipc_ns->mq_msg_default);
740 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
741 ipc_ns->mq_msgsize_default);
742 ret = mq_attr_ok(ipc_ns, &def_attr);
743 if (ret)
744 return ERR_PTR(ret);
745 }
746
747 mode &= ~current_umask();
748 ret = vfs_create(dir, path->dentry, mode, true);
749 path->dentry->d_fsdata = NULL;
750 if (ret)
751 return ERR_PTR(ret);
752 return dentry_open(path, oflag, cred);
753}
754
755/* Opens existing queue */
756static struct file *do_open(struct path *path, int oflag)
757{
758 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
759 MAY_READ | MAY_WRITE };
760 int acc;
761 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
762 return ERR_PTR(-EINVAL);
763 acc = oflag2acc[oflag & O_ACCMODE];
764 if (inode_permission(d_inode(path->dentry), acc))
765 return ERR_PTR(-EACCES);
766 return dentry_open(path, oflag, current_cred());
767}
768
769SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
770 struct mq_attr __user *, u_attr)
771{
772 struct path path;
773 struct file *filp;
774 struct filename *name;
775 struct mq_attr attr;
776 int fd, error;
777 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
778 struct vfsmount *mnt = ipc_ns->mq_mnt;
779 struct dentry *root = mnt->mnt_root;
780 int ro;
781
782 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
783 return -EFAULT;
784
785 audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
786
787 if (IS_ERR(name = getname(u_name)))
788 return PTR_ERR(name);
789
790 fd = get_unused_fd_flags(O_CLOEXEC);
791 if (fd < 0)
792 goto out_putname;
793
794 ro = mnt_want_write(mnt); /* we'll drop it in any case */
795 error = 0;
796 inode_lock(d_inode(root));
797 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
798 if (IS_ERR(path.dentry)) {
799 error = PTR_ERR(path.dentry);
800 goto out_putfd;
801 }
802 path.mnt = mntget(mnt);
803
804 if (oflag & O_CREAT) {
805 if (d_really_is_positive(path.dentry)) { /* entry already exists */
806 audit_inode(name, path.dentry, 0);
807 if (oflag & O_EXCL) {
808 error = -EEXIST;
809 goto out;
810 }
811 filp = do_open(&path, oflag);
812 } else {
813 if (ro) {
814 error = ro;
815 goto out;
816 }
817 audit_inode_parent_hidden(name, root);
818 filp = do_create(ipc_ns, d_inode(root),
819 &path, oflag, mode,
820 u_attr ? &attr : NULL);
821 }
822 } else {
823 if (d_really_is_negative(path.dentry)) {
824 error = -ENOENT;
825 goto out;
826 }
827 audit_inode(name, path.dentry, 0);
828 filp = do_open(&path, oflag);
829 }
830
831 if (!IS_ERR(filp))
832 fd_install(fd, filp);
833 else
834 error = PTR_ERR(filp);
835out:
836 path_put(&path);
837out_putfd:
838 if (error) {
839 put_unused_fd(fd);
840 fd = error;
841 }
842 inode_unlock(d_inode(root));
843 if (!ro)
844 mnt_drop_write(mnt);
845out_putname:
846 putname(name);
847 return fd;
848}
849
850SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
851{
852 int err;
853 struct filename *name;
854 struct dentry *dentry;
855 struct inode *inode = NULL;
856 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
857 struct vfsmount *mnt = ipc_ns->mq_mnt;
858
859 name = getname(u_name);
860 if (IS_ERR(name))
861 return PTR_ERR(name);
862
863 audit_inode_parent_hidden(name, mnt->mnt_root);
864 err = mnt_want_write(mnt);
865 if (err)
866 goto out_name;
867 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
868 dentry = lookup_one_len(name->name, mnt->mnt_root,
869 strlen(name->name));
870 if (IS_ERR(dentry)) {
871 err = PTR_ERR(dentry);
872 goto out_unlock;
873 }
874
875 inode = d_inode(dentry);
876 if (!inode) {
877 err = -ENOENT;
878 } else {
879 ihold(inode);
880 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
881 }
882 dput(dentry);
883
884out_unlock:
885 inode_unlock(d_inode(mnt->mnt_root));
886 if (inode)
887 iput(inode);
888 mnt_drop_write(mnt);
889out_name:
890 putname(name);
891
892 return err;
893}
894
895/* Pipelined send and receive functions.
896 *
897 * If a receiver finds no waiting message, then it registers itself in the
898 * list of waiting receivers. A sender checks that list before adding the new
899 * message into the message array. If there is a waiting receiver, then it
900 * bypasses the message array and directly hands the message over to the
901 * receiver. The receiver accepts the message and returns without grabbing the
902 * queue spinlock:
903 *
904 * - Set pointer to message.
905 * - Queue the receiver task for later wakeup (without the info->lock).
906 * - Update its state to STATE_READY. Now the receiver can continue.
907 * - Wake up the process after the lock is dropped. Should the process wake up
908 * before this wakeup (due to a timeout or a signal) it will either see
909 * STATE_READY and continue or acquire the lock to check the state again.
910 *
911 * The same algorithm is used for senders.
912 */
913
914/* pipelined_send() - send a message directly to the task waiting in
915 * sys_mq_timedreceive() (without inserting message into a queue).
916 */
917static inline void pipelined_send(struct wake_q_head *wake_q,
918 struct mqueue_inode_info *info,
919 struct msg_msg *message,
920 struct ext_wait_queue *receiver)
921{
922 receiver->msg = message;
923 list_del(&receiver->list);
924 wake_q_add(wake_q, receiver->task);
925 /*
926 * Rely on the implicit cmpxchg barrier from wake_q_add such
927 * that we can ensure that updating receiver->state is the last
928 * write operation: As once set, the receiver can continue,
929 * and if we don't have the reference count from the wake_q,
930 * yet, at that point we can later have a use-after-free
931 * condition and bogus wakeup.
932 */
933 receiver->state = STATE_READY;
934}
935
936/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
937 * gets its message and put to the queue (we have one free place for sure). */
938static inline void pipelined_receive(struct wake_q_head *wake_q,
939 struct mqueue_inode_info *info)
940{
941 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
942
943 if (!sender) {
944 /* for poll */
945 wake_up_interruptible(&info->wait_q);
946 return;
947 }
948 if (msg_insert(sender->msg, info))
949 return;
950
951 list_del(&sender->list);
952 wake_q_add(wake_q, sender->task);
953 sender->state = STATE_READY;
954}
955
956SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
957 size_t, msg_len, unsigned int, msg_prio,
958 const struct timespec __user *, u_abs_timeout)
959{
960 struct fd f;
961 struct inode *inode;
962 struct ext_wait_queue wait;
963 struct ext_wait_queue *receiver;
964 struct msg_msg *msg_ptr;
965 struct mqueue_inode_info *info;
966 ktime_t expires, *timeout = NULL;
967 struct timespec ts;
968 struct posix_msg_tree_node *new_leaf = NULL;
969 int ret = 0;
970 DEFINE_WAKE_Q(wake_q);
971
972 if (u_abs_timeout) {
973 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
974 if (res)
975 return res;
976 timeout = &expires;
977 }
978
979 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
980 return -EINVAL;
981
982 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
983
984 f = fdget(mqdes);
985 if (unlikely(!f.file)) {
986 ret = -EBADF;
987 goto out;
988 }
989
990 inode = file_inode(f.file);
991 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
992 ret = -EBADF;
993 goto out_fput;
994 }
995 info = MQUEUE_I(inode);
996 audit_file(f.file);
997
998 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
999 ret = -EBADF;
1000 goto out_fput;
1001 }
1002
1003 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1004 ret = -EMSGSIZE;
1005 goto out_fput;
1006 }
1007
1008 /* First try to allocate memory, before doing anything with
1009 * existing queues. */
1010 msg_ptr = load_msg(u_msg_ptr, msg_len);
1011 if (IS_ERR(msg_ptr)) {
1012 ret = PTR_ERR(msg_ptr);
1013 goto out_fput;
1014 }
1015 msg_ptr->m_ts = msg_len;
1016 msg_ptr->m_type = msg_prio;
1017
1018 /*
1019 * msg_insert really wants us to have a valid, spare node struct so
1020 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1021 * fall back to that if necessary.
1022 */
1023 if (!info->node_cache)
1024 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1025
1026 spin_lock(&info->lock);
1027
1028 if (!info->node_cache && new_leaf) {
1029 /* Save our speculative allocation into the cache */
1030 INIT_LIST_HEAD(&new_leaf->msg_list);
1031 info->node_cache = new_leaf;
1032 new_leaf = NULL;
1033 } else {
1034 kfree(new_leaf);
1035 }
1036
1037 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1038 if (f.file->f_flags & O_NONBLOCK) {
1039 ret = -EAGAIN;
1040 } else {
1041 wait.task = current;
1042 wait.msg = (void *) msg_ptr;
1043 wait.state = STATE_NONE;
1044 ret = wq_sleep(info, SEND, timeout, &wait);
1045 /*
1046 * wq_sleep must be called with info->lock held, and
1047 * returns with the lock released
1048 */
1049 goto out_free;
1050 }
1051 } else {
1052 receiver = wq_get_first_waiter(info, RECV);
1053 if (receiver) {
1054 pipelined_send(&wake_q, info, msg_ptr, receiver);
1055 } else {
1056 /* adds message to the queue */
1057 ret = msg_insert(msg_ptr, info);
1058 if (ret)
1059 goto out_unlock;
1060 __do_notify(info);
1061 }
1062 inode->i_atime = inode->i_mtime = inode->i_ctime =
1063 current_time(inode);
1064 }
1065out_unlock:
1066 spin_unlock(&info->lock);
1067 wake_up_q(&wake_q);
1068out_free:
1069 if (ret)
1070 free_msg(msg_ptr);
1071out_fput:
1072 fdput(f);
1073out:
1074 return ret;
1075}
1076
1077SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1078 size_t, msg_len, unsigned int __user *, u_msg_prio,
1079 const struct timespec __user *, u_abs_timeout)
1080{
1081 ssize_t ret;
1082 struct msg_msg *msg_ptr;
1083 struct fd f;
1084 struct inode *inode;
1085 struct mqueue_inode_info *info;
1086 struct ext_wait_queue wait;
1087 ktime_t expires, *timeout = NULL;
1088 struct timespec ts;
1089 struct posix_msg_tree_node *new_leaf = NULL;
1090
1091 if (u_abs_timeout) {
1092 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1093 if (res)
1094 return res;
1095 timeout = &expires;
1096 }
1097
1098 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1099
1100 f = fdget(mqdes);
1101 if (unlikely(!f.file)) {
1102 ret = -EBADF;
1103 goto out;
1104 }
1105
1106 inode = file_inode(f.file);
1107 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1108 ret = -EBADF;
1109 goto out_fput;
1110 }
1111 info = MQUEUE_I(inode);
1112 audit_file(f.file);
1113
1114 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1115 ret = -EBADF;
1116 goto out_fput;
1117 }
1118
1119 /* checks if buffer is big enough */
1120 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1121 ret = -EMSGSIZE;
1122 goto out_fput;
1123 }
1124
1125 /*
1126 * msg_insert really wants us to have a valid, spare node struct so
1127 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1128 * fall back to that if necessary.
1129 */
1130 if (!info->node_cache)
1131 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1132
1133 spin_lock(&info->lock);
1134
1135 if (!info->node_cache && new_leaf) {
1136 /* Save our speculative allocation into the cache */
1137 INIT_LIST_HEAD(&new_leaf->msg_list);
1138 info->node_cache = new_leaf;
1139 } else {
1140 kfree(new_leaf);
1141 }
1142
1143 if (info->attr.mq_curmsgs == 0) {
1144 if (f.file->f_flags & O_NONBLOCK) {
1145 spin_unlock(&info->lock);
1146 ret = -EAGAIN;
1147 } else {
1148 wait.task = current;
1149 wait.state = STATE_NONE;
1150 ret = wq_sleep(info, RECV, timeout, &wait);
1151 msg_ptr = wait.msg;
1152 }
1153 } else {
1154 DEFINE_WAKE_Q(wake_q);
1155
1156 msg_ptr = msg_get(info);
1157
1158 inode->i_atime = inode->i_mtime = inode->i_ctime =
1159 current_time(inode);
1160
1161 /* There is now free space in queue. */
1162 pipelined_receive(&wake_q, info);
1163 spin_unlock(&info->lock);
1164 wake_up_q(&wake_q);
1165 ret = 0;
1166 }
1167 if (ret == 0) {
1168 ret = msg_ptr->m_ts;
1169
1170 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1171 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1172 ret = -EFAULT;
1173 }
1174 free_msg(msg_ptr);
1175 }
1176out_fput:
1177 fdput(f);
1178out:
1179 return ret;
1180}
1181
1182/*
1183 * Notes: the case when user wants us to deregister (with NULL as pointer)
1184 * and he isn't currently owner of notification, will be silently discarded.
1185 * It isn't explicitly defined in the POSIX.
1186 */
1187SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1188 const struct sigevent __user *, u_notification)
1189{
1190 int ret;
1191 struct fd f;
1192 struct sock *sock;
1193 struct inode *inode;
1194 struct sigevent notification;
1195 struct mqueue_inode_info *info;
1196 struct sk_buff *nc;
1197
1198 if (u_notification) {
1199 if (copy_from_user(¬ification, u_notification,
1200 sizeof(struct sigevent)))
1201 return -EFAULT;
1202 }
1203
1204 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL);
1205
1206 nc = NULL;
1207 sock = NULL;
1208 if (u_notification != NULL) {
1209 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1210 notification.sigev_notify != SIGEV_SIGNAL &&
1211 notification.sigev_notify != SIGEV_THREAD))
1212 return -EINVAL;
1213 if (notification.sigev_notify == SIGEV_SIGNAL &&
1214 !valid_signal(notification.sigev_signo)) {
1215 return -EINVAL;
1216 }
1217 if (notification.sigev_notify == SIGEV_THREAD) {
1218 long timeo;
1219
1220 /* create the notify skb */
1221 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1222 if (!nc) {
1223 ret = -ENOMEM;
1224 goto out;
1225 }
1226 if (copy_from_user(nc->data,
1227 notification.sigev_value.sival_ptr,
1228 NOTIFY_COOKIE_LEN)) {
1229 ret = -EFAULT;
1230 goto out;
1231 }
1232
1233 /* TODO: add a header? */
1234 skb_put(nc, NOTIFY_COOKIE_LEN);
1235 /* and attach it to the socket */
1236retry:
1237 f = fdget(notification.sigev_signo);
1238 if (!f.file) {
1239 ret = -EBADF;
1240 goto out;
1241 }
1242 sock = netlink_getsockbyfilp(f.file);
1243 fdput(f);
1244 if (IS_ERR(sock)) {
1245 ret = PTR_ERR(sock);
1246 sock = NULL;
1247 goto out;
1248 }
1249
1250 timeo = MAX_SCHEDULE_TIMEOUT;
1251 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1252 if (ret == 1)
1253 goto retry;
1254 if (ret) {
1255 sock = NULL;
1256 nc = NULL;
1257 goto out;
1258 }
1259 }
1260 }
1261
1262 f = fdget(mqdes);
1263 if (!f.file) {
1264 ret = -EBADF;
1265 goto out;
1266 }
1267
1268 inode = file_inode(f.file);
1269 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1270 ret = -EBADF;
1271 goto out_fput;
1272 }
1273 info = MQUEUE_I(inode);
1274
1275 ret = 0;
1276 spin_lock(&info->lock);
1277 if (u_notification == NULL) {
1278 if (info->notify_owner == task_tgid(current)) {
1279 remove_notification(info);
1280 inode->i_atime = inode->i_ctime = current_time(inode);
1281 }
1282 } else if (info->notify_owner != NULL) {
1283 ret = -EBUSY;
1284 } else {
1285 switch (notification.sigev_notify) {
1286 case SIGEV_NONE:
1287 info->notify.sigev_notify = SIGEV_NONE;
1288 break;
1289 case SIGEV_THREAD:
1290 info->notify_sock = sock;
1291 info->notify_cookie = nc;
1292 sock = NULL;
1293 nc = NULL;
1294 info->notify.sigev_notify = SIGEV_THREAD;
1295 break;
1296 case SIGEV_SIGNAL:
1297 info->notify.sigev_signo = notification.sigev_signo;
1298 info->notify.sigev_value = notification.sigev_value;
1299 info->notify.sigev_notify = SIGEV_SIGNAL;
1300 break;
1301 }
1302
1303 info->notify_owner = get_pid(task_tgid(current));
1304 info->notify_user_ns = get_user_ns(current_user_ns());
1305 inode->i_atime = inode->i_ctime = current_time(inode);
1306 }
1307 spin_unlock(&info->lock);
1308out_fput:
1309 fdput(f);
1310out:
1311 if (sock)
1312 netlink_detachskb(sock, nc);
1313 else if (nc)
1314 dev_kfree_skb(nc);
1315
1316 return ret;
1317}
1318
1319SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1320 const struct mq_attr __user *, u_mqstat,
1321 struct mq_attr __user *, u_omqstat)
1322{
1323 int ret;
1324 struct mq_attr mqstat, omqstat;
1325 struct fd f;
1326 struct inode *inode;
1327 struct mqueue_inode_info *info;
1328
1329 if (u_mqstat != NULL) {
1330 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1331 return -EFAULT;
1332 if (mqstat.mq_flags & (~O_NONBLOCK))
1333 return -EINVAL;
1334 }
1335
1336 f = fdget(mqdes);
1337 if (!f.file) {
1338 ret = -EBADF;
1339 goto out;
1340 }
1341
1342 inode = file_inode(f.file);
1343 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1344 ret = -EBADF;
1345 goto out_fput;
1346 }
1347 info = MQUEUE_I(inode);
1348
1349 spin_lock(&info->lock);
1350
1351 omqstat = info->attr;
1352 omqstat.mq_flags = f.file->f_flags & O_NONBLOCK;
1353 if (u_mqstat) {
1354 audit_mq_getsetattr(mqdes, &mqstat);
1355 spin_lock(&f.file->f_lock);
1356 if (mqstat.mq_flags & O_NONBLOCK)
1357 f.file->f_flags |= O_NONBLOCK;
1358 else
1359 f.file->f_flags &= ~O_NONBLOCK;
1360 spin_unlock(&f.file->f_lock);
1361
1362 inode->i_atime = inode->i_ctime = current_time(inode);
1363 }
1364
1365 spin_unlock(&info->lock);
1366
1367 ret = 0;
1368 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1369 sizeof(struct mq_attr)))
1370 ret = -EFAULT;
1371
1372out_fput:
1373 fdput(f);
1374out:
1375 return ret;
1376}
1377
1378static const struct inode_operations mqueue_dir_inode_operations = {
1379 .lookup = simple_lookup,
1380 .create = mqueue_create,
1381 .unlink = mqueue_unlink,
1382};
1383
1384static const struct file_operations mqueue_file_operations = {
1385 .flush = mqueue_flush_file,
1386 .poll = mqueue_poll_file,
1387 .read = mqueue_read_file,
1388 .llseek = default_llseek,
1389};
1390
1391static const struct super_operations mqueue_super_ops = {
1392 .alloc_inode = mqueue_alloc_inode,
1393 .destroy_inode = mqueue_destroy_inode,
1394 .evict_inode = mqueue_evict_inode,
1395 .statfs = simple_statfs,
1396};
1397
1398static struct file_system_type mqueue_fs_type = {
1399 .name = "mqueue",
1400 .mount = mqueue_mount,
1401 .kill_sb = kill_litter_super,
1402 .fs_flags = FS_USERNS_MOUNT,
1403};
1404
1405int mq_init_ns(struct ipc_namespace *ns)
1406{
1407 ns->mq_queues_count = 0;
1408 ns->mq_queues_max = DFLT_QUEUESMAX;
1409 ns->mq_msg_max = DFLT_MSGMAX;
1410 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1411 ns->mq_msg_default = DFLT_MSG;
1412 ns->mq_msgsize_default = DFLT_MSGSIZE;
1413
1414 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1415 if (IS_ERR(ns->mq_mnt)) {
1416 int err = PTR_ERR(ns->mq_mnt);
1417 ns->mq_mnt = NULL;
1418 return err;
1419 }
1420 return 0;
1421}
1422
1423void mq_clear_sbinfo(struct ipc_namespace *ns)
1424{
1425 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1426}
1427
1428void mq_put_mnt(struct ipc_namespace *ns)
1429{
1430 kern_unmount(ns->mq_mnt);
1431}
1432
1433static int __init init_mqueue_fs(void)
1434{
1435 int error;
1436
1437 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1438 sizeof(struct mqueue_inode_info), 0,
1439 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1440 if (mqueue_inode_cachep == NULL)
1441 return -ENOMEM;
1442
1443 /* ignore failures - they are not fatal */
1444 mq_sysctl_table = mq_register_sysctl_table();
1445
1446 error = register_filesystem(&mqueue_fs_type);
1447 if (error)
1448 goto out_sysctl;
1449
1450 spin_lock_init(&mq_lock);
1451
1452 error = mq_init_ns(&init_ipc_ns);
1453 if (error)
1454 goto out_filesystem;
1455
1456 return 0;
1457
1458out_filesystem:
1459 unregister_filesystem(&mqueue_fs_type);
1460out_sysctl:
1461 if (mq_sysctl_table)
1462 unregister_sysctl_table(mq_sysctl_table);
1463 kmem_cache_destroy(mqueue_inode_cachep);
1464 return error;
1465}
1466
1467device_initcall(init_mqueue_fs);
1/*
2 * POSIX message queues filesystem for Linux.
3 *
4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
5 * Michal Wronski (michal.wronski@gmail.com)
6 *
7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
8 * Lockless receive & send, fd based notify:
9 * Manfred Spraul (manfred@colorfullife.com)
10 *
11 * Audit: George Wilson (ltcgcw@us.ibm.com)
12 *
13 * This file is released under the GPL.
14 */
15
16#include <linux/capability.h>
17#include <linux/init.h>
18#include <linux/pagemap.h>
19#include <linux/file.h>
20#include <linux/mount.h>
21#include <linux/namei.h>
22#include <linux/sysctl.h>
23#include <linux/poll.h>
24#include <linux/mqueue.h>
25#include <linux/msg.h>
26#include <linux/skbuff.h>
27#include <linux/vmalloc.h>
28#include <linux/netlink.h>
29#include <linux/syscalls.h>
30#include <linux/audit.h>
31#include <linux/signal.h>
32#include <linux/mutex.h>
33#include <linux/nsproxy.h>
34#include <linux/pid.h>
35#include <linux/ipc_namespace.h>
36#include <linux/user_namespace.h>
37#include <linux/slab.h>
38#include <linux/sched/wake_q.h>
39#include <linux/sched/signal.h>
40#include <linux/sched/user.h>
41
42#include <net/sock.h>
43#include "util.h"
44
45#define MQUEUE_MAGIC 0x19800202
46#define DIRENT_SIZE 20
47#define FILENT_SIZE 80
48
49#define SEND 0
50#define RECV 1
51
52#define STATE_NONE 0
53#define STATE_READY 1
54
55struct posix_msg_tree_node {
56 struct rb_node rb_node;
57 struct list_head msg_list;
58 int priority;
59};
60
61struct ext_wait_queue { /* queue of sleeping tasks */
62 struct task_struct *task;
63 struct list_head list;
64 struct msg_msg *msg; /* ptr of loaded message */
65 int state; /* one of STATE_* values */
66};
67
68struct mqueue_inode_info {
69 spinlock_t lock;
70 struct inode vfs_inode;
71 wait_queue_head_t wait_q;
72
73 struct rb_root msg_tree;
74 struct posix_msg_tree_node *node_cache;
75 struct mq_attr attr;
76
77 struct sigevent notify;
78 struct pid *notify_owner;
79 struct user_namespace *notify_user_ns;
80 struct user_struct *user; /* user who created, for accounting */
81 struct sock *notify_sock;
82 struct sk_buff *notify_cookie;
83
84 /* for tasks waiting for free space and messages, respectively */
85 struct ext_wait_queue e_wait_q[2];
86
87 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
88};
89
90static const struct inode_operations mqueue_dir_inode_operations;
91static const struct file_operations mqueue_file_operations;
92static const struct super_operations mqueue_super_ops;
93static void remove_notification(struct mqueue_inode_info *info);
94
95static struct kmem_cache *mqueue_inode_cachep;
96
97static struct ctl_table_header *mq_sysctl_table;
98
99static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
100{
101 return container_of(inode, struct mqueue_inode_info, vfs_inode);
102}
103
104/*
105 * This routine should be called with the mq_lock held.
106 */
107static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
108{
109 return get_ipc_ns(inode->i_sb->s_fs_info);
110}
111
112static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
113{
114 struct ipc_namespace *ns;
115
116 spin_lock(&mq_lock);
117 ns = __get_ns_from_inode(inode);
118 spin_unlock(&mq_lock);
119 return ns;
120}
121
122/* Auxiliary functions to manipulate messages' list */
123static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
124{
125 struct rb_node **p, *parent = NULL;
126 struct posix_msg_tree_node *leaf;
127
128 p = &info->msg_tree.rb_node;
129 while (*p) {
130 parent = *p;
131 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
132
133 if (likely(leaf->priority == msg->m_type))
134 goto insert_msg;
135 else if (msg->m_type < leaf->priority)
136 p = &(*p)->rb_left;
137 else
138 p = &(*p)->rb_right;
139 }
140 if (info->node_cache) {
141 leaf = info->node_cache;
142 info->node_cache = NULL;
143 } else {
144 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
145 if (!leaf)
146 return -ENOMEM;
147 INIT_LIST_HEAD(&leaf->msg_list);
148 }
149 leaf->priority = msg->m_type;
150 rb_link_node(&leaf->rb_node, parent, p);
151 rb_insert_color(&leaf->rb_node, &info->msg_tree);
152insert_msg:
153 info->attr.mq_curmsgs++;
154 info->qsize += msg->m_ts;
155 list_add_tail(&msg->m_list, &leaf->msg_list);
156 return 0;
157}
158
159static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
160{
161 struct rb_node **p, *parent = NULL;
162 struct posix_msg_tree_node *leaf;
163 struct msg_msg *msg;
164
165try_again:
166 p = &info->msg_tree.rb_node;
167 while (*p) {
168 parent = *p;
169 /*
170 * During insert, low priorities go to the left and high to the
171 * right. On receive, we want the highest priorities first, so
172 * walk all the way to the right.
173 */
174 p = &(*p)->rb_right;
175 }
176 if (!parent) {
177 if (info->attr.mq_curmsgs) {
178 pr_warn_once("Inconsistency in POSIX message queue, "
179 "no tree element, but supposedly messages "
180 "should exist!\n");
181 info->attr.mq_curmsgs = 0;
182 }
183 return NULL;
184 }
185 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
186 if (unlikely(list_empty(&leaf->msg_list))) {
187 pr_warn_once("Inconsistency in POSIX message queue, "
188 "empty leaf node but we haven't implemented "
189 "lazy leaf delete!\n");
190 rb_erase(&leaf->rb_node, &info->msg_tree);
191 if (info->node_cache) {
192 kfree(leaf);
193 } else {
194 info->node_cache = leaf;
195 }
196 goto try_again;
197 } else {
198 msg = list_first_entry(&leaf->msg_list,
199 struct msg_msg, m_list);
200 list_del(&msg->m_list);
201 if (list_empty(&leaf->msg_list)) {
202 rb_erase(&leaf->rb_node, &info->msg_tree);
203 if (info->node_cache) {
204 kfree(leaf);
205 } else {
206 info->node_cache = leaf;
207 }
208 }
209 }
210 info->attr.mq_curmsgs--;
211 info->qsize -= msg->m_ts;
212 return msg;
213}
214
215static struct inode *mqueue_get_inode(struct super_block *sb,
216 struct ipc_namespace *ipc_ns, umode_t mode,
217 struct mq_attr *attr)
218{
219 struct user_struct *u = current_user();
220 struct inode *inode;
221 int ret = -ENOMEM;
222
223 inode = new_inode(sb);
224 if (!inode)
225 goto err;
226
227 inode->i_ino = get_next_ino();
228 inode->i_mode = mode;
229 inode->i_uid = current_fsuid();
230 inode->i_gid = current_fsgid();
231 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
232
233 if (S_ISREG(mode)) {
234 struct mqueue_inode_info *info;
235 unsigned long mq_bytes, mq_treesize;
236
237 inode->i_fop = &mqueue_file_operations;
238 inode->i_size = FILENT_SIZE;
239 /* mqueue specific info */
240 info = MQUEUE_I(inode);
241 spin_lock_init(&info->lock);
242 init_waitqueue_head(&info->wait_q);
243 INIT_LIST_HEAD(&info->e_wait_q[0].list);
244 INIT_LIST_HEAD(&info->e_wait_q[1].list);
245 info->notify_owner = NULL;
246 info->notify_user_ns = NULL;
247 info->qsize = 0;
248 info->user = NULL; /* set when all is ok */
249 info->msg_tree = RB_ROOT;
250 info->node_cache = NULL;
251 memset(&info->attr, 0, sizeof(info->attr));
252 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
253 ipc_ns->mq_msg_default);
254 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
255 ipc_ns->mq_msgsize_default);
256 if (attr) {
257 info->attr.mq_maxmsg = attr->mq_maxmsg;
258 info->attr.mq_msgsize = attr->mq_msgsize;
259 }
260 /*
261 * We used to allocate a static array of pointers and account
262 * the size of that array as well as one msg_msg struct per
263 * possible message into the queue size. That's no longer
264 * accurate as the queue is now an rbtree and will grow and
265 * shrink depending on usage patterns. We can, however, still
266 * account one msg_msg struct per message, but the nodes are
267 * allocated depending on priority usage, and most programs
268 * only use one, or a handful, of priorities. However, since
269 * this is pinned memory, we need to assume worst case, so
270 * that means the min(mq_maxmsg, max_priorities) * struct
271 * posix_msg_tree_node.
272 */
273
274 ret = -EINVAL;
275 if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
276 goto out_inode;
277 if (capable(CAP_SYS_RESOURCE)) {
278 if (info->attr.mq_maxmsg > HARD_MSGMAX ||
279 info->attr.mq_msgsize > HARD_MSGSIZEMAX)
280 goto out_inode;
281 } else {
282 if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
283 info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
284 goto out_inode;
285 }
286 ret = -EOVERFLOW;
287 /* check for overflow */
288 if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
289 goto out_inode;
290 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
291 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
292 sizeof(struct posix_msg_tree_node);
293 mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
294 if (mq_bytes + mq_treesize < mq_bytes)
295 goto out_inode;
296 mq_bytes += mq_treesize;
297 spin_lock(&mq_lock);
298 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
299 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
300 spin_unlock(&mq_lock);
301 /* mqueue_evict_inode() releases info->messages */
302 ret = -EMFILE;
303 goto out_inode;
304 }
305 u->mq_bytes += mq_bytes;
306 spin_unlock(&mq_lock);
307
308 /* all is ok */
309 info->user = get_uid(u);
310 } else if (S_ISDIR(mode)) {
311 inc_nlink(inode);
312 /* Some things misbehave if size == 0 on a directory */
313 inode->i_size = 2 * DIRENT_SIZE;
314 inode->i_op = &mqueue_dir_inode_operations;
315 inode->i_fop = &simple_dir_operations;
316 }
317
318 return inode;
319out_inode:
320 iput(inode);
321err:
322 return ERR_PTR(ret);
323}
324
325static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
326{
327 struct inode *inode;
328 struct ipc_namespace *ns = sb->s_fs_info;
329
330 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
331 sb->s_blocksize = PAGE_SIZE;
332 sb->s_blocksize_bits = PAGE_SHIFT;
333 sb->s_magic = MQUEUE_MAGIC;
334 sb->s_op = &mqueue_super_ops;
335
336 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
337 if (IS_ERR(inode))
338 return PTR_ERR(inode);
339
340 sb->s_root = d_make_root(inode);
341 if (!sb->s_root)
342 return -ENOMEM;
343 return 0;
344}
345
346static struct dentry *mqueue_mount(struct file_system_type *fs_type,
347 int flags, const char *dev_name,
348 void *data)
349{
350 struct ipc_namespace *ns;
351 if (flags & SB_KERNMOUNT) {
352 ns = data;
353 data = NULL;
354 } else {
355 ns = current->nsproxy->ipc_ns;
356 }
357 return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super);
358}
359
360static void init_once(void *foo)
361{
362 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
363
364 inode_init_once(&p->vfs_inode);
365}
366
367static struct inode *mqueue_alloc_inode(struct super_block *sb)
368{
369 struct mqueue_inode_info *ei;
370
371 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
372 if (!ei)
373 return NULL;
374 return &ei->vfs_inode;
375}
376
377static void mqueue_i_callback(struct rcu_head *head)
378{
379 struct inode *inode = container_of(head, struct inode, i_rcu);
380 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
381}
382
383static void mqueue_destroy_inode(struct inode *inode)
384{
385 call_rcu(&inode->i_rcu, mqueue_i_callback);
386}
387
388static void mqueue_evict_inode(struct inode *inode)
389{
390 struct mqueue_inode_info *info;
391 struct user_struct *user;
392 unsigned long mq_bytes, mq_treesize;
393 struct ipc_namespace *ipc_ns;
394 struct msg_msg *msg;
395
396 clear_inode(inode);
397
398 if (S_ISDIR(inode->i_mode))
399 return;
400
401 ipc_ns = get_ns_from_inode(inode);
402 info = MQUEUE_I(inode);
403 spin_lock(&info->lock);
404 while ((msg = msg_get(info)) != NULL)
405 free_msg(msg);
406 kfree(info->node_cache);
407 spin_unlock(&info->lock);
408
409 /* Total amount of bytes accounted for the mqueue */
410 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
411 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
412 sizeof(struct posix_msg_tree_node);
413
414 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
415 info->attr.mq_msgsize);
416
417 user = info->user;
418 if (user) {
419 spin_lock(&mq_lock);
420 user->mq_bytes -= mq_bytes;
421 /*
422 * get_ns_from_inode() ensures that the
423 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
424 * to which we now hold a reference, or it is NULL.
425 * We can't put it here under mq_lock, though.
426 */
427 if (ipc_ns)
428 ipc_ns->mq_queues_count--;
429 spin_unlock(&mq_lock);
430 free_uid(user);
431 }
432 if (ipc_ns)
433 put_ipc_ns(ipc_ns);
434}
435
436static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
437{
438 struct inode *dir = dentry->d_parent->d_inode;
439 struct inode *inode;
440 struct mq_attr *attr = arg;
441 int error;
442 struct ipc_namespace *ipc_ns;
443
444 spin_lock(&mq_lock);
445 ipc_ns = __get_ns_from_inode(dir);
446 if (!ipc_ns) {
447 error = -EACCES;
448 goto out_unlock;
449 }
450
451 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
452 !capable(CAP_SYS_RESOURCE)) {
453 error = -ENOSPC;
454 goto out_unlock;
455 }
456 ipc_ns->mq_queues_count++;
457 spin_unlock(&mq_lock);
458
459 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
460 if (IS_ERR(inode)) {
461 error = PTR_ERR(inode);
462 spin_lock(&mq_lock);
463 ipc_ns->mq_queues_count--;
464 goto out_unlock;
465 }
466
467 put_ipc_ns(ipc_ns);
468 dir->i_size += DIRENT_SIZE;
469 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
470
471 d_instantiate(dentry, inode);
472 dget(dentry);
473 return 0;
474out_unlock:
475 spin_unlock(&mq_lock);
476 if (ipc_ns)
477 put_ipc_ns(ipc_ns);
478 return error;
479}
480
481static int mqueue_create(struct inode *dir, struct dentry *dentry,
482 umode_t mode, bool excl)
483{
484 return mqueue_create_attr(dentry, mode, NULL);
485}
486
487static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
488{
489 struct inode *inode = d_inode(dentry);
490
491 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
492 dir->i_size -= DIRENT_SIZE;
493 drop_nlink(inode);
494 dput(dentry);
495 return 0;
496}
497
498/*
499* This is routine for system read from queue file.
500* To avoid mess with doing here some sort of mq_receive we allow
501* to read only queue size & notification info (the only values
502* that are interesting from user point of view and aren't accessible
503* through std routines)
504*/
505static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
506 size_t count, loff_t *off)
507{
508 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
509 char buffer[FILENT_SIZE];
510 ssize_t ret;
511
512 spin_lock(&info->lock);
513 snprintf(buffer, sizeof(buffer),
514 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
515 info->qsize,
516 info->notify_owner ? info->notify.sigev_notify : 0,
517 (info->notify_owner &&
518 info->notify.sigev_notify == SIGEV_SIGNAL) ?
519 info->notify.sigev_signo : 0,
520 pid_vnr(info->notify_owner));
521 spin_unlock(&info->lock);
522 buffer[sizeof(buffer)-1] = '\0';
523
524 ret = simple_read_from_buffer(u_data, count, off, buffer,
525 strlen(buffer));
526 if (ret <= 0)
527 return ret;
528
529 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
530 return ret;
531}
532
533static int mqueue_flush_file(struct file *filp, fl_owner_t id)
534{
535 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
536
537 spin_lock(&info->lock);
538 if (task_tgid(current) == info->notify_owner)
539 remove_notification(info);
540
541 spin_unlock(&info->lock);
542 return 0;
543}
544
545static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
546{
547 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
548 __poll_t retval = 0;
549
550 poll_wait(filp, &info->wait_q, poll_tab);
551
552 spin_lock(&info->lock);
553 if (info->attr.mq_curmsgs)
554 retval = EPOLLIN | EPOLLRDNORM;
555
556 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
557 retval |= EPOLLOUT | EPOLLWRNORM;
558 spin_unlock(&info->lock);
559
560 return retval;
561}
562
563/* Adds current to info->e_wait_q[sr] before element with smaller prio */
564static void wq_add(struct mqueue_inode_info *info, int sr,
565 struct ext_wait_queue *ewp)
566{
567 struct ext_wait_queue *walk;
568
569 ewp->task = current;
570
571 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
572 if (walk->task->prio <= current->prio) {
573 list_add_tail(&ewp->list, &walk->list);
574 return;
575 }
576 }
577 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
578}
579
580/*
581 * Puts current task to sleep. Caller must hold queue lock. After return
582 * lock isn't held.
583 * sr: SEND or RECV
584 */
585static int wq_sleep(struct mqueue_inode_info *info, int sr,
586 ktime_t *timeout, struct ext_wait_queue *ewp)
587 __releases(&info->lock)
588{
589 int retval;
590 signed long time;
591
592 wq_add(info, sr, ewp);
593
594 for (;;) {
595 __set_current_state(TASK_INTERRUPTIBLE);
596
597 spin_unlock(&info->lock);
598 time = schedule_hrtimeout_range_clock(timeout, 0,
599 HRTIMER_MODE_ABS, CLOCK_REALTIME);
600
601 if (ewp->state == STATE_READY) {
602 retval = 0;
603 goto out;
604 }
605 spin_lock(&info->lock);
606 if (ewp->state == STATE_READY) {
607 retval = 0;
608 goto out_unlock;
609 }
610 if (signal_pending(current)) {
611 retval = -ERESTARTSYS;
612 break;
613 }
614 if (time == 0) {
615 retval = -ETIMEDOUT;
616 break;
617 }
618 }
619 list_del(&ewp->list);
620out_unlock:
621 spin_unlock(&info->lock);
622out:
623 return retval;
624}
625
626/*
627 * Returns waiting task that should be serviced first or NULL if none exists
628 */
629static struct ext_wait_queue *wq_get_first_waiter(
630 struct mqueue_inode_info *info, int sr)
631{
632 struct list_head *ptr;
633
634 ptr = info->e_wait_q[sr].list.prev;
635 if (ptr == &info->e_wait_q[sr].list)
636 return NULL;
637 return list_entry(ptr, struct ext_wait_queue, list);
638}
639
640
641static inline void set_cookie(struct sk_buff *skb, char code)
642{
643 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
644}
645
646/*
647 * The next function is only to split too long sys_mq_timedsend
648 */
649static void __do_notify(struct mqueue_inode_info *info)
650{
651 /* notification
652 * invoked when there is registered process and there isn't process
653 * waiting synchronously for message AND state of queue changed from
654 * empty to not empty. Here we are sure that no one is waiting
655 * synchronously. */
656 if (info->notify_owner &&
657 info->attr.mq_curmsgs == 1) {
658 struct siginfo sig_i;
659 switch (info->notify.sigev_notify) {
660 case SIGEV_NONE:
661 break;
662 case SIGEV_SIGNAL:
663 /* sends signal */
664
665 clear_siginfo(&sig_i);
666 sig_i.si_signo = info->notify.sigev_signo;
667 sig_i.si_errno = 0;
668 sig_i.si_code = SI_MESGQ;
669 sig_i.si_value = info->notify.sigev_value;
670 /* map current pid/uid into info->owner's namespaces */
671 rcu_read_lock();
672 sig_i.si_pid = task_tgid_nr_ns(current,
673 ns_of_pid(info->notify_owner));
674 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
675 rcu_read_unlock();
676
677 kill_pid_info(info->notify.sigev_signo,
678 &sig_i, info->notify_owner);
679 break;
680 case SIGEV_THREAD:
681 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
682 netlink_sendskb(info->notify_sock, info->notify_cookie);
683 break;
684 }
685 /* after notification unregisters process */
686 put_pid(info->notify_owner);
687 put_user_ns(info->notify_user_ns);
688 info->notify_owner = NULL;
689 info->notify_user_ns = NULL;
690 }
691 wake_up(&info->wait_q);
692}
693
694static int prepare_timeout(const struct timespec __user *u_abs_timeout,
695 struct timespec64 *ts)
696{
697 if (get_timespec64(ts, u_abs_timeout))
698 return -EFAULT;
699 if (!timespec64_valid(ts))
700 return -EINVAL;
701 return 0;
702}
703
704static void remove_notification(struct mqueue_inode_info *info)
705{
706 if (info->notify_owner != NULL &&
707 info->notify.sigev_notify == SIGEV_THREAD) {
708 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
709 netlink_sendskb(info->notify_sock, info->notify_cookie);
710 }
711 put_pid(info->notify_owner);
712 put_user_ns(info->notify_user_ns);
713 info->notify_owner = NULL;
714 info->notify_user_ns = NULL;
715}
716
717static int prepare_open(struct dentry *dentry, int oflag, int ro,
718 umode_t mode, struct filename *name,
719 struct mq_attr *attr)
720{
721 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
722 MAY_READ | MAY_WRITE };
723 int acc;
724
725 if (d_really_is_negative(dentry)) {
726 if (!(oflag & O_CREAT))
727 return -ENOENT;
728 if (ro)
729 return ro;
730 audit_inode_parent_hidden(name, dentry->d_parent);
731 return vfs_mkobj(dentry, mode & ~current_umask(),
732 mqueue_create_attr, attr);
733 }
734 /* it already existed */
735 audit_inode(name, dentry, 0);
736 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
737 return -EEXIST;
738 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
739 return -EINVAL;
740 acc = oflag2acc[oflag & O_ACCMODE];
741 return inode_permission(d_inode(dentry), acc);
742}
743
744static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
745 struct mq_attr *attr)
746{
747 struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
748 struct dentry *root = mnt->mnt_root;
749 struct filename *name;
750 struct path path;
751 int fd, error;
752 int ro;
753
754 audit_mq_open(oflag, mode, attr);
755
756 if (IS_ERR(name = getname(u_name)))
757 return PTR_ERR(name);
758
759 fd = get_unused_fd_flags(O_CLOEXEC);
760 if (fd < 0)
761 goto out_putname;
762
763 ro = mnt_want_write(mnt); /* we'll drop it in any case */
764 inode_lock(d_inode(root));
765 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
766 if (IS_ERR(path.dentry)) {
767 error = PTR_ERR(path.dentry);
768 goto out_putfd;
769 }
770 path.mnt = mntget(mnt);
771 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
772 if (!error) {
773 struct file *file = dentry_open(&path, oflag, current_cred());
774 if (!IS_ERR(file))
775 fd_install(fd, file);
776 else
777 error = PTR_ERR(file);
778 }
779 path_put(&path);
780out_putfd:
781 if (error) {
782 put_unused_fd(fd);
783 fd = error;
784 }
785 inode_unlock(d_inode(root));
786 if (!ro)
787 mnt_drop_write(mnt);
788out_putname:
789 putname(name);
790 return fd;
791}
792
793SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
794 struct mq_attr __user *, u_attr)
795{
796 struct mq_attr attr;
797 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
798 return -EFAULT;
799
800 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
801}
802
803SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
804{
805 int err;
806 struct filename *name;
807 struct dentry *dentry;
808 struct inode *inode = NULL;
809 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
810 struct vfsmount *mnt = ipc_ns->mq_mnt;
811
812 name = getname(u_name);
813 if (IS_ERR(name))
814 return PTR_ERR(name);
815
816 audit_inode_parent_hidden(name, mnt->mnt_root);
817 err = mnt_want_write(mnt);
818 if (err)
819 goto out_name;
820 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
821 dentry = lookup_one_len(name->name, mnt->mnt_root,
822 strlen(name->name));
823 if (IS_ERR(dentry)) {
824 err = PTR_ERR(dentry);
825 goto out_unlock;
826 }
827
828 inode = d_inode(dentry);
829 if (!inode) {
830 err = -ENOENT;
831 } else {
832 ihold(inode);
833 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
834 }
835 dput(dentry);
836
837out_unlock:
838 inode_unlock(d_inode(mnt->mnt_root));
839 if (inode)
840 iput(inode);
841 mnt_drop_write(mnt);
842out_name:
843 putname(name);
844
845 return err;
846}
847
848/* Pipelined send and receive functions.
849 *
850 * If a receiver finds no waiting message, then it registers itself in the
851 * list of waiting receivers. A sender checks that list before adding the new
852 * message into the message array. If there is a waiting receiver, then it
853 * bypasses the message array and directly hands the message over to the
854 * receiver. The receiver accepts the message and returns without grabbing the
855 * queue spinlock:
856 *
857 * - Set pointer to message.
858 * - Queue the receiver task for later wakeup (without the info->lock).
859 * - Update its state to STATE_READY. Now the receiver can continue.
860 * - Wake up the process after the lock is dropped. Should the process wake up
861 * before this wakeup (due to a timeout or a signal) it will either see
862 * STATE_READY and continue or acquire the lock to check the state again.
863 *
864 * The same algorithm is used for senders.
865 */
866
867/* pipelined_send() - send a message directly to the task waiting in
868 * sys_mq_timedreceive() (without inserting message into a queue).
869 */
870static inline void pipelined_send(struct wake_q_head *wake_q,
871 struct mqueue_inode_info *info,
872 struct msg_msg *message,
873 struct ext_wait_queue *receiver)
874{
875 receiver->msg = message;
876 list_del(&receiver->list);
877 wake_q_add(wake_q, receiver->task);
878 /*
879 * Rely on the implicit cmpxchg barrier from wake_q_add such
880 * that we can ensure that updating receiver->state is the last
881 * write operation: As once set, the receiver can continue,
882 * and if we don't have the reference count from the wake_q,
883 * yet, at that point we can later have a use-after-free
884 * condition and bogus wakeup.
885 */
886 receiver->state = STATE_READY;
887}
888
889/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
890 * gets its message and put to the queue (we have one free place for sure). */
891static inline void pipelined_receive(struct wake_q_head *wake_q,
892 struct mqueue_inode_info *info)
893{
894 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
895
896 if (!sender) {
897 /* for poll */
898 wake_up_interruptible(&info->wait_q);
899 return;
900 }
901 if (msg_insert(sender->msg, info))
902 return;
903
904 list_del(&sender->list);
905 wake_q_add(wake_q, sender->task);
906 sender->state = STATE_READY;
907}
908
909static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
910 size_t msg_len, unsigned int msg_prio,
911 struct timespec64 *ts)
912{
913 struct fd f;
914 struct inode *inode;
915 struct ext_wait_queue wait;
916 struct ext_wait_queue *receiver;
917 struct msg_msg *msg_ptr;
918 struct mqueue_inode_info *info;
919 ktime_t expires, *timeout = NULL;
920 struct posix_msg_tree_node *new_leaf = NULL;
921 int ret = 0;
922 DEFINE_WAKE_Q(wake_q);
923
924 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
925 return -EINVAL;
926
927 if (ts) {
928 expires = timespec64_to_ktime(*ts);
929 timeout = &expires;
930 }
931
932 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
933
934 f = fdget(mqdes);
935 if (unlikely(!f.file)) {
936 ret = -EBADF;
937 goto out;
938 }
939
940 inode = file_inode(f.file);
941 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
942 ret = -EBADF;
943 goto out_fput;
944 }
945 info = MQUEUE_I(inode);
946 audit_file(f.file);
947
948 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
949 ret = -EBADF;
950 goto out_fput;
951 }
952
953 if (unlikely(msg_len > info->attr.mq_msgsize)) {
954 ret = -EMSGSIZE;
955 goto out_fput;
956 }
957
958 /* First try to allocate memory, before doing anything with
959 * existing queues. */
960 msg_ptr = load_msg(u_msg_ptr, msg_len);
961 if (IS_ERR(msg_ptr)) {
962 ret = PTR_ERR(msg_ptr);
963 goto out_fput;
964 }
965 msg_ptr->m_ts = msg_len;
966 msg_ptr->m_type = msg_prio;
967
968 /*
969 * msg_insert really wants us to have a valid, spare node struct so
970 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
971 * fall back to that if necessary.
972 */
973 if (!info->node_cache)
974 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
975
976 spin_lock(&info->lock);
977
978 if (!info->node_cache && new_leaf) {
979 /* Save our speculative allocation into the cache */
980 INIT_LIST_HEAD(&new_leaf->msg_list);
981 info->node_cache = new_leaf;
982 new_leaf = NULL;
983 } else {
984 kfree(new_leaf);
985 }
986
987 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
988 if (f.file->f_flags & O_NONBLOCK) {
989 ret = -EAGAIN;
990 } else {
991 wait.task = current;
992 wait.msg = (void *) msg_ptr;
993 wait.state = STATE_NONE;
994 ret = wq_sleep(info, SEND, timeout, &wait);
995 /*
996 * wq_sleep must be called with info->lock held, and
997 * returns with the lock released
998 */
999 goto out_free;
1000 }
1001 } else {
1002 receiver = wq_get_first_waiter(info, RECV);
1003 if (receiver) {
1004 pipelined_send(&wake_q, info, msg_ptr, receiver);
1005 } else {
1006 /* adds message to the queue */
1007 ret = msg_insert(msg_ptr, info);
1008 if (ret)
1009 goto out_unlock;
1010 __do_notify(info);
1011 }
1012 inode->i_atime = inode->i_mtime = inode->i_ctime =
1013 current_time(inode);
1014 }
1015out_unlock:
1016 spin_unlock(&info->lock);
1017 wake_up_q(&wake_q);
1018out_free:
1019 if (ret)
1020 free_msg(msg_ptr);
1021out_fput:
1022 fdput(f);
1023out:
1024 return ret;
1025}
1026
1027static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1028 size_t msg_len, unsigned int __user *u_msg_prio,
1029 struct timespec64 *ts)
1030{
1031 ssize_t ret;
1032 struct msg_msg *msg_ptr;
1033 struct fd f;
1034 struct inode *inode;
1035 struct mqueue_inode_info *info;
1036 struct ext_wait_queue wait;
1037 ktime_t expires, *timeout = NULL;
1038 struct posix_msg_tree_node *new_leaf = NULL;
1039
1040 if (ts) {
1041 expires = timespec64_to_ktime(*ts);
1042 timeout = &expires;
1043 }
1044
1045 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1046
1047 f = fdget(mqdes);
1048 if (unlikely(!f.file)) {
1049 ret = -EBADF;
1050 goto out;
1051 }
1052
1053 inode = file_inode(f.file);
1054 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1055 ret = -EBADF;
1056 goto out_fput;
1057 }
1058 info = MQUEUE_I(inode);
1059 audit_file(f.file);
1060
1061 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1062 ret = -EBADF;
1063 goto out_fput;
1064 }
1065
1066 /* checks if buffer is big enough */
1067 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1068 ret = -EMSGSIZE;
1069 goto out_fput;
1070 }
1071
1072 /*
1073 * msg_insert really wants us to have a valid, spare node struct so
1074 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1075 * fall back to that if necessary.
1076 */
1077 if (!info->node_cache)
1078 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1079
1080 spin_lock(&info->lock);
1081
1082 if (!info->node_cache && new_leaf) {
1083 /* Save our speculative allocation into the cache */
1084 INIT_LIST_HEAD(&new_leaf->msg_list);
1085 info->node_cache = new_leaf;
1086 } else {
1087 kfree(new_leaf);
1088 }
1089
1090 if (info->attr.mq_curmsgs == 0) {
1091 if (f.file->f_flags & O_NONBLOCK) {
1092 spin_unlock(&info->lock);
1093 ret = -EAGAIN;
1094 } else {
1095 wait.task = current;
1096 wait.state = STATE_NONE;
1097 ret = wq_sleep(info, RECV, timeout, &wait);
1098 msg_ptr = wait.msg;
1099 }
1100 } else {
1101 DEFINE_WAKE_Q(wake_q);
1102
1103 msg_ptr = msg_get(info);
1104
1105 inode->i_atime = inode->i_mtime = inode->i_ctime =
1106 current_time(inode);
1107
1108 /* There is now free space in queue. */
1109 pipelined_receive(&wake_q, info);
1110 spin_unlock(&info->lock);
1111 wake_up_q(&wake_q);
1112 ret = 0;
1113 }
1114 if (ret == 0) {
1115 ret = msg_ptr->m_ts;
1116
1117 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1118 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1119 ret = -EFAULT;
1120 }
1121 free_msg(msg_ptr);
1122 }
1123out_fput:
1124 fdput(f);
1125out:
1126 return ret;
1127}
1128
1129SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1130 size_t, msg_len, unsigned int, msg_prio,
1131 const struct timespec __user *, u_abs_timeout)
1132{
1133 struct timespec64 ts, *p = NULL;
1134 if (u_abs_timeout) {
1135 int res = prepare_timeout(u_abs_timeout, &ts);
1136 if (res)
1137 return res;
1138 p = &ts;
1139 }
1140 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1141}
1142
1143SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1144 size_t, msg_len, unsigned int __user *, u_msg_prio,
1145 const struct timespec __user *, u_abs_timeout)
1146{
1147 struct timespec64 ts, *p = NULL;
1148 if (u_abs_timeout) {
1149 int res = prepare_timeout(u_abs_timeout, &ts);
1150 if (res)
1151 return res;
1152 p = &ts;
1153 }
1154 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1155}
1156
1157/*
1158 * Notes: the case when user wants us to deregister (with NULL as pointer)
1159 * and he isn't currently owner of notification, will be silently discarded.
1160 * It isn't explicitly defined in the POSIX.
1161 */
1162static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1163{
1164 int ret;
1165 struct fd f;
1166 struct sock *sock;
1167 struct inode *inode;
1168 struct mqueue_inode_info *info;
1169 struct sk_buff *nc;
1170
1171 audit_mq_notify(mqdes, notification);
1172
1173 nc = NULL;
1174 sock = NULL;
1175 if (notification != NULL) {
1176 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1177 notification->sigev_notify != SIGEV_SIGNAL &&
1178 notification->sigev_notify != SIGEV_THREAD))
1179 return -EINVAL;
1180 if (notification->sigev_notify == SIGEV_SIGNAL &&
1181 !valid_signal(notification->sigev_signo)) {
1182 return -EINVAL;
1183 }
1184 if (notification->sigev_notify == SIGEV_THREAD) {
1185 long timeo;
1186
1187 /* create the notify skb */
1188 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1189 if (!nc) {
1190 ret = -ENOMEM;
1191 goto out;
1192 }
1193 if (copy_from_user(nc->data,
1194 notification->sigev_value.sival_ptr,
1195 NOTIFY_COOKIE_LEN)) {
1196 ret = -EFAULT;
1197 goto out;
1198 }
1199
1200 /* TODO: add a header? */
1201 skb_put(nc, NOTIFY_COOKIE_LEN);
1202 /* and attach it to the socket */
1203retry:
1204 f = fdget(notification->sigev_signo);
1205 if (!f.file) {
1206 ret = -EBADF;
1207 goto out;
1208 }
1209 sock = netlink_getsockbyfilp(f.file);
1210 fdput(f);
1211 if (IS_ERR(sock)) {
1212 ret = PTR_ERR(sock);
1213 sock = NULL;
1214 goto out;
1215 }
1216
1217 timeo = MAX_SCHEDULE_TIMEOUT;
1218 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1219 if (ret == 1) {
1220 sock = NULL;
1221 goto retry;
1222 }
1223 if (ret) {
1224 sock = NULL;
1225 nc = NULL;
1226 goto out;
1227 }
1228 }
1229 }
1230
1231 f = fdget(mqdes);
1232 if (!f.file) {
1233 ret = -EBADF;
1234 goto out;
1235 }
1236
1237 inode = file_inode(f.file);
1238 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1239 ret = -EBADF;
1240 goto out_fput;
1241 }
1242 info = MQUEUE_I(inode);
1243
1244 ret = 0;
1245 spin_lock(&info->lock);
1246 if (notification == NULL) {
1247 if (info->notify_owner == task_tgid(current)) {
1248 remove_notification(info);
1249 inode->i_atime = inode->i_ctime = current_time(inode);
1250 }
1251 } else if (info->notify_owner != NULL) {
1252 ret = -EBUSY;
1253 } else {
1254 switch (notification->sigev_notify) {
1255 case SIGEV_NONE:
1256 info->notify.sigev_notify = SIGEV_NONE;
1257 break;
1258 case SIGEV_THREAD:
1259 info->notify_sock = sock;
1260 info->notify_cookie = nc;
1261 sock = NULL;
1262 nc = NULL;
1263 info->notify.sigev_notify = SIGEV_THREAD;
1264 break;
1265 case SIGEV_SIGNAL:
1266 info->notify.sigev_signo = notification->sigev_signo;
1267 info->notify.sigev_value = notification->sigev_value;
1268 info->notify.sigev_notify = SIGEV_SIGNAL;
1269 break;
1270 }
1271
1272 info->notify_owner = get_pid(task_tgid(current));
1273 info->notify_user_ns = get_user_ns(current_user_ns());
1274 inode->i_atime = inode->i_ctime = current_time(inode);
1275 }
1276 spin_unlock(&info->lock);
1277out_fput:
1278 fdput(f);
1279out:
1280 if (sock)
1281 netlink_detachskb(sock, nc);
1282 else if (nc)
1283 dev_kfree_skb(nc);
1284
1285 return ret;
1286}
1287
1288SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1289 const struct sigevent __user *, u_notification)
1290{
1291 struct sigevent n, *p = NULL;
1292 if (u_notification) {
1293 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1294 return -EFAULT;
1295 p = &n;
1296 }
1297 return do_mq_notify(mqdes, p);
1298}
1299
1300static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1301{
1302 struct fd f;
1303 struct inode *inode;
1304 struct mqueue_inode_info *info;
1305
1306 if (new && (new->mq_flags & (~O_NONBLOCK)))
1307 return -EINVAL;
1308
1309 f = fdget(mqdes);
1310 if (!f.file)
1311 return -EBADF;
1312
1313 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1314 fdput(f);
1315 return -EBADF;
1316 }
1317
1318 inode = file_inode(f.file);
1319 info = MQUEUE_I(inode);
1320
1321 spin_lock(&info->lock);
1322
1323 if (old) {
1324 *old = info->attr;
1325 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1326 }
1327 if (new) {
1328 audit_mq_getsetattr(mqdes, new);
1329 spin_lock(&f.file->f_lock);
1330 if (new->mq_flags & O_NONBLOCK)
1331 f.file->f_flags |= O_NONBLOCK;
1332 else
1333 f.file->f_flags &= ~O_NONBLOCK;
1334 spin_unlock(&f.file->f_lock);
1335
1336 inode->i_atime = inode->i_ctime = current_time(inode);
1337 }
1338
1339 spin_unlock(&info->lock);
1340 fdput(f);
1341 return 0;
1342}
1343
1344SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1345 const struct mq_attr __user *, u_mqstat,
1346 struct mq_attr __user *, u_omqstat)
1347{
1348 int ret;
1349 struct mq_attr mqstat, omqstat;
1350 struct mq_attr *new = NULL, *old = NULL;
1351
1352 if (u_mqstat) {
1353 new = &mqstat;
1354 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1355 return -EFAULT;
1356 }
1357 if (u_omqstat)
1358 old = &omqstat;
1359
1360 ret = do_mq_getsetattr(mqdes, new, old);
1361 if (ret || !old)
1362 return ret;
1363
1364 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1365 return -EFAULT;
1366 return 0;
1367}
1368
1369#ifdef CONFIG_COMPAT
1370
1371struct compat_mq_attr {
1372 compat_long_t mq_flags; /* message queue flags */
1373 compat_long_t mq_maxmsg; /* maximum number of messages */
1374 compat_long_t mq_msgsize; /* maximum message size */
1375 compat_long_t mq_curmsgs; /* number of messages currently queued */
1376 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1377};
1378
1379static inline int get_compat_mq_attr(struct mq_attr *attr,
1380 const struct compat_mq_attr __user *uattr)
1381{
1382 struct compat_mq_attr v;
1383
1384 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1385 return -EFAULT;
1386
1387 memset(attr, 0, sizeof(*attr));
1388 attr->mq_flags = v.mq_flags;
1389 attr->mq_maxmsg = v.mq_maxmsg;
1390 attr->mq_msgsize = v.mq_msgsize;
1391 attr->mq_curmsgs = v.mq_curmsgs;
1392 return 0;
1393}
1394
1395static inline int put_compat_mq_attr(const struct mq_attr *attr,
1396 struct compat_mq_attr __user *uattr)
1397{
1398 struct compat_mq_attr v;
1399
1400 memset(&v, 0, sizeof(v));
1401 v.mq_flags = attr->mq_flags;
1402 v.mq_maxmsg = attr->mq_maxmsg;
1403 v.mq_msgsize = attr->mq_msgsize;
1404 v.mq_curmsgs = attr->mq_curmsgs;
1405 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1406 return -EFAULT;
1407 return 0;
1408}
1409
1410COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1411 int, oflag, compat_mode_t, mode,
1412 struct compat_mq_attr __user *, u_attr)
1413{
1414 struct mq_attr attr, *p = NULL;
1415 if (u_attr && oflag & O_CREAT) {
1416 p = &attr;
1417 if (get_compat_mq_attr(&attr, u_attr))
1418 return -EFAULT;
1419 }
1420 return do_mq_open(u_name, oflag, mode, p);
1421}
1422
1423static int compat_prepare_timeout(const struct compat_timespec __user *p,
1424 struct timespec64 *ts)
1425{
1426 if (compat_get_timespec64(ts, p))
1427 return -EFAULT;
1428 if (!timespec64_valid(ts))
1429 return -EINVAL;
1430 return 0;
1431}
1432
1433COMPAT_SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes,
1434 const char __user *, u_msg_ptr,
1435 compat_size_t, msg_len, unsigned int, msg_prio,
1436 const struct compat_timespec __user *, u_abs_timeout)
1437{
1438 struct timespec64 ts, *p = NULL;
1439 if (u_abs_timeout) {
1440 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1441 if (res)
1442 return res;
1443 p = &ts;
1444 }
1445 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1446}
1447
1448COMPAT_SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes,
1449 char __user *, u_msg_ptr,
1450 compat_size_t, msg_len, unsigned int __user *, u_msg_prio,
1451 const struct compat_timespec __user *, u_abs_timeout)
1452{
1453 struct timespec64 ts, *p = NULL;
1454 if (u_abs_timeout) {
1455 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1456 if (res)
1457 return res;
1458 p = &ts;
1459 }
1460 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1461}
1462
1463COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1464 const struct compat_sigevent __user *, u_notification)
1465{
1466 struct sigevent n, *p = NULL;
1467 if (u_notification) {
1468 if (get_compat_sigevent(&n, u_notification))
1469 return -EFAULT;
1470 if (n.sigev_notify == SIGEV_THREAD)
1471 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1472 p = &n;
1473 }
1474 return do_mq_notify(mqdes, p);
1475}
1476
1477COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1478 const struct compat_mq_attr __user *, u_mqstat,
1479 struct compat_mq_attr __user *, u_omqstat)
1480{
1481 int ret;
1482 struct mq_attr mqstat, omqstat;
1483 struct mq_attr *new = NULL, *old = NULL;
1484
1485 if (u_mqstat) {
1486 new = &mqstat;
1487 if (get_compat_mq_attr(new, u_mqstat))
1488 return -EFAULT;
1489 }
1490 if (u_omqstat)
1491 old = &omqstat;
1492
1493 ret = do_mq_getsetattr(mqdes, new, old);
1494 if (ret || !old)
1495 return ret;
1496
1497 if (put_compat_mq_attr(old, u_omqstat))
1498 return -EFAULT;
1499 return 0;
1500}
1501#endif
1502
1503static const struct inode_operations mqueue_dir_inode_operations = {
1504 .lookup = simple_lookup,
1505 .create = mqueue_create,
1506 .unlink = mqueue_unlink,
1507};
1508
1509static const struct file_operations mqueue_file_operations = {
1510 .flush = mqueue_flush_file,
1511 .poll = mqueue_poll_file,
1512 .read = mqueue_read_file,
1513 .llseek = default_llseek,
1514};
1515
1516static const struct super_operations mqueue_super_ops = {
1517 .alloc_inode = mqueue_alloc_inode,
1518 .destroy_inode = mqueue_destroy_inode,
1519 .evict_inode = mqueue_evict_inode,
1520 .statfs = simple_statfs,
1521};
1522
1523static struct file_system_type mqueue_fs_type = {
1524 .name = "mqueue",
1525 .mount = mqueue_mount,
1526 .kill_sb = kill_litter_super,
1527 .fs_flags = FS_USERNS_MOUNT,
1528};
1529
1530int mq_init_ns(struct ipc_namespace *ns)
1531{
1532 ns->mq_queues_count = 0;
1533 ns->mq_queues_max = DFLT_QUEUESMAX;
1534 ns->mq_msg_max = DFLT_MSGMAX;
1535 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1536 ns->mq_msg_default = DFLT_MSG;
1537 ns->mq_msgsize_default = DFLT_MSGSIZE;
1538
1539 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1540 if (IS_ERR(ns->mq_mnt)) {
1541 int err = PTR_ERR(ns->mq_mnt);
1542 ns->mq_mnt = NULL;
1543 return err;
1544 }
1545 return 0;
1546}
1547
1548void mq_clear_sbinfo(struct ipc_namespace *ns)
1549{
1550 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1551}
1552
1553void mq_put_mnt(struct ipc_namespace *ns)
1554{
1555 kern_unmount(ns->mq_mnt);
1556}
1557
1558static int __init init_mqueue_fs(void)
1559{
1560 int error;
1561
1562 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1563 sizeof(struct mqueue_inode_info), 0,
1564 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1565 if (mqueue_inode_cachep == NULL)
1566 return -ENOMEM;
1567
1568 /* ignore failures - they are not fatal */
1569 mq_sysctl_table = mq_register_sysctl_table();
1570
1571 error = register_filesystem(&mqueue_fs_type);
1572 if (error)
1573 goto out_sysctl;
1574
1575 spin_lock_init(&mq_lock);
1576
1577 error = mq_init_ns(&init_ipc_ns);
1578 if (error)
1579 goto out_filesystem;
1580
1581 return 0;
1582
1583out_filesystem:
1584 unregister_filesystem(&mqueue_fs_type);
1585out_sysctl:
1586 if (mq_sysctl_table)
1587 unregister_sysctl_table(mq_sysctl_table);
1588 kmem_cache_destroy(mqueue_inode_cachep);
1589 return error;
1590}
1591
1592device_initcall(init_mqueue_fs);