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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_PENDING 1
51#define STATE_READY 2
52
53struct posix_msg_tree_node {
54 struct rb_node rb_node;
55 struct list_head msg_list;
56 int priority;
57};
58
59struct ext_wait_queue { /* queue of sleeping tasks */
60 struct task_struct *task;
61 struct list_head list;
62 struct msg_msg *msg; /* ptr of loaded message */
63 int state; /* one of STATE_* values */
64};
65
66struct mqueue_inode_info {
67 spinlock_t lock;
68 struct inode vfs_inode;
69 wait_queue_head_t wait_q;
70
71 struct rb_root msg_tree;
72 struct posix_msg_tree_node *node_cache;
73 struct mq_attr attr;
74
75 struct sigevent notify;
76 struct pid *notify_owner;
77 struct user_namespace *notify_user_ns;
78 struct user_struct *user; /* user who created, for accounting */
79 struct sock *notify_sock;
80 struct sk_buff *notify_cookie;
81
82 /* for tasks waiting for free space and messages, respectively */
83 struct ext_wait_queue e_wait_q[2];
84
85 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
86};
87
88static const struct inode_operations mqueue_dir_inode_operations;
89static const struct file_operations mqueue_file_operations;
90static const struct super_operations mqueue_super_ops;
91static void remove_notification(struct mqueue_inode_info *info);
92
93static struct kmem_cache *mqueue_inode_cachep;
94
95static struct ctl_table_header *mq_sysctl_table;
96
97static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
98{
99 return container_of(inode, struct mqueue_inode_info, vfs_inode);
100}
101
102/*
103 * This routine should be called with the mq_lock held.
104 */
105static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
106{
107 return get_ipc_ns(inode->i_sb->s_fs_info);
108}
109
110static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
111{
112 struct ipc_namespace *ns;
113
114 spin_lock(&mq_lock);
115 ns = __get_ns_from_inode(inode);
116 spin_unlock(&mq_lock);
117 return ns;
118}
119
120/* Auxiliary functions to manipulate messages' list */
121static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
122{
123 struct rb_node **p, *parent = NULL;
124 struct posix_msg_tree_node *leaf;
125
126 p = &info->msg_tree.rb_node;
127 while (*p) {
128 parent = *p;
129 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
130
131 if (likely(leaf->priority == msg->m_type))
132 goto insert_msg;
133 else if (msg->m_type < leaf->priority)
134 p = &(*p)->rb_left;
135 else
136 p = &(*p)->rb_right;
137 }
138 if (info->node_cache) {
139 leaf = info->node_cache;
140 info->node_cache = NULL;
141 } else {
142 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
143 if (!leaf)
144 return -ENOMEM;
145 INIT_LIST_HEAD(&leaf->msg_list);
146 info->qsize += sizeof(*leaf);
147 }
148 leaf->priority = msg->m_type;
149 rb_link_node(&leaf->rb_node, parent, p);
150 rb_insert_color(&leaf->rb_node, &info->msg_tree);
151insert_msg:
152 info->attr.mq_curmsgs++;
153 info->qsize += msg->m_ts;
154 list_add_tail(&msg->m_list, &leaf->msg_list);
155 return 0;
156}
157
158static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
159{
160 struct rb_node **p, *parent = NULL;
161 struct posix_msg_tree_node *leaf;
162 struct msg_msg *msg;
163
164try_again:
165 p = &info->msg_tree.rb_node;
166 while (*p) {
167 parent = *p;
168 /*
169 * During insert, low priorities go to the left and high to the
170 * right. On receive, we want the highest priorities first, so
171 * walk all the way to the right.
172 */
173 p = &(*p)->rb_right;
174 }
175 if (!parent) {
176 if (info->attr.mq_curmsgs) {
177 pr_warn_once("Inconsistency in POSIX message queue, "
178 "no tree element, but supposedly messages "
179 "should exist!\n");
180 info->attr.mq_curmsgs = 0;
181 }
182 return NULL;
183 }
184 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
185 if (unlikely(list_empty(&leaf->msg_list))) {
186 pr_warn_once("Inconsistency in POSIX message queue, "
187 "empty leaf node but we haven't implemented "
188 "lazy leaf delete!\n");
189 rb_erase(&leaf->rb_node, &info->msg_tree);
190 if (info->node_cache) {
191 info->qsize -= sizeof(*leaf);
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 info->qsize -= sizeof(*leaf);
205 kfree(leaf);
206 } else {
207 info->node_cache = leaf;
208 }
209 }
210 }
211 info->attr.mq_curmsgs--;
212 info->qsize -= msg->m_ts;
213 return msg;
214}
215
216static struct inode *mqueue_get_inode(struct super_block *sb,
217 struct ipc_namespace *ipc_ns, umode_t mode,
218 struct mq_attr *attr)
219{
220 struct user_struct *u = current_user();
221 struct inode *inode;
222 int ret = -ENOMEM;
223
224 inode = new_inode(sb);
225 if (!inode)
226 goto err;
227
228 inode->i_ino = get_next_ino();
229 inode->i_mode = mode;
230 inode->i_uid = current_fsuid();
231 inode->i_gid = current_fsgid();
232 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
233
234 if (S_ISREG(mode)) {
235 struct mqueue_inode_info *info;
236 unsigned long mq_bytes, mq_treesize;
237
238 inode->i_fop = &mqueue_file_operations;
239 inode->i_size = FILENT_SIZE;
240 /* mqueue specific info */
241 info = MQUEUE_I(inode);
242 spin_lock_init(&info->lock);
243 init_waitqueue_head(&info->wait_q);
244 INIT_LIST_HEAD(&info->e_wait_q[0].list);
245 INIT_LIST_HEAD(&info->e_wait_q[1].list);
246 info->notify_owner = NULL;
247 info->notify_user_ns = NULL;
248 info->qsize = 0;
249 info->user = NULL; /* set when all is ok */
250 info->msg_tree = RB_ROOT;
251 info->node_cache = NULL;
252 memset(&info->attr, 0, sizeof(info->attr));
253 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
254 ipc_ns->mq_msg_default);
255 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
256 ipc_ns->mq_msgsize_default);
257 if (attr) {
258 info->attr.mq_maxmsg = attr->mq_maxmsg;
259 info->attr.mq_msgsize = attr->mq_msgsize;
260 }
261 /*
262 * We used to allocate a static array of pointers and account
263 * the size of that array as well as one msg_msg struct per
264 * possible message into the queue size. That's no longer
265 * accurate as the queue is now an rbtree and will grow and
266 * shrink depending on usage patterns. We can, however, still
267 * account one msg_msg struct per message, but the nodes are
268 * allocated depending on priority usage, and most programs
269 * only use one, or a handful, of priorities. However, since
270 * this is pinned memory, we need to assume worst case, so
271 * that means the min(mq_maxmsg, max_priorities) * struct
272 * posix_msg_tree_node.
273 */
274 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
275 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
276 sizeof(struct posix_msg_tree_node);
277
278 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
279 info->attr.mq_msgsize);
280
281 spin_lock(&mq_lock);
282 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
283 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
284 spin_unlock(&mq_lock);
285 /* mqueue_evict_inode() releases info->messages */
286 ret = -EMFILE;
287 goto out_inode;
288 }
289 u->mq_bytes += mq_bytes;
290 spin_unlock(&mq_lock);
291
292 /* all is ok */
293 info->user = get_uid(u);
294 } else if (S_ISDIR(mode)) {
295 inc_nlink(inode);
296 /* Some things misbehave if size == 0 on a directory */
297 inode->i_size = 2 * DIRENT_SIZE;
298 inode->i_op = &mqueue_dir_inode_operations;
299 inode->i_fop = &simple_dir_operations;
300 }
301
302 return inode;
303out_inode:
304 iput(inode);
305err:
306 return ERR_PTR(ret);
307}
308
309static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
310{
311 struct inode *inode;
312 struct ipc_namespace *ns = data;
313
314 sb->s_blocksize = PAGE_CACHE_SIZE;
315 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
316 sb->s_magic = MQUEUE_MAGIC;
317 sb->s_op = &mqueue_super_ops;
318
319 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
320 if (IS_ERR(inode))
321 return PTR_ERR(inode);
322
323 sb->s_root = d_make_root(inode);
324 if (!sb->s_root)
325 return -ENOMEM;
326 return 0;
327}
328
329static struct dentry *mqueue_mount(struct file_system_type *fs_type,
330 int flags, const char *dev_name,
331 void *data)
332{
333 if (!(flags & MS_KERNMOUNT)) {
334 struct ipc_namespace *ns = current->nsproxy->ipc_ns;
335 /* Don't allow mounting unless the caller has CAP_SYS_ADMIN
336 * over the ipc namespace.
337 */
338 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
339 return ERR_PTR(-EPERM);
340
341 data = ns;
342 }
343 return mount_ns(fs_type, flags, data, mqueue_fill_super);
344}
345
346static void init_once(void *foo)
347{
348 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
349
350 inode_init_once(&p->vfs_inode);
351}
352
353static struct inode *mqueue_alloc_inode(struct super_block *sb)
354{
355 struct mqueue_inode_info *ei;
356
357 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
358 if (!ei)
359 return NULL;
360 return &ei->vfs_inode;
361}
362
363static void mqueue_i_callback(struct rcu_head *head)
364{
365 struct inode *inode = container_of(head, struct inode, i_rcu);
366 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
367}
368
369static void mqueue_destroy_inode(struct inode *inode)
370{
371 call_rcu(&inode->i_rcu, mqueue_i_callback);
372}
373
374static void mqueue_evict_inode(struct inode *inode)
375{
376 struct mqueue_inode_info *info;
377 struct user_struct *user;
378 unsigned long mq_bytes, mq_treesize;
379 struct ipc_namespace *ipc_ns;
380 struct msg_msg *msg;
381
382 clear_inode(inode);
383
384 if (S_ISDIR(inode->i_mode))
385 return;
386
387 ipc_ns = get_ns_from_inode(inode);
388 info = MQUEUE_I(inode);
389 spin_lock(&info->lock);
390 while ((msg = msg_get(info)) != NULL)
391 free_msg(msg);
392 kfree(info->node_cache);
393 spin_unlock(&info->lock);
394
395 /* Total amount of bytes accounted for the mqueue */
396 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
397 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
398 sizeof(struct posix_msg_tree_node);
399
400 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
401 info->attr.mq_msgsize);
402
403 user = info->user;
404 if (user) {
405 spin_lock(&mq_lock);
406 user->mq_bytes -= mq_bytes;
407 /*
408 * get_ns_from_inode() ensures that the
409 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
410 * to which we now hold a reference, or it is NULL.
411 * We can't put it here under mq_lock, though.
412 */
413 if (ipc_ns)
414 ipc_ns->mq_queues_count--;
415 spin_unlock(&mq_lock);
416 free_uid(user);
417 }
418 if (ipc_ns)
419 put_ipc_ns(ipc_ns);
420}
421
422static int mqueue_create(struct inode *dir, struct dentry *dentry,
423 umode_t mode, bool excl)
424{
425 struct inode *inode;
426 struct mq_attr *attr = dentry->d_fsdata;
427 int error;
428 struct ipc_namespace *ipc_ns;
429
430 spin_lock(&mq_lock);
431 ipc_ns = __get_ns_from_inode(dir);
432 if (!ipc_ns) {
433 error = -EACCES;
434 goto out_unlock;
435 }
436
437 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
438 !capable(CAP_SYS_RESOURCE)) {
439 error = -ENOSPC;
440 goto out_unlock;
441 }
442 ipc_ns->mq_queues_count++;
443 spin_unlock(&mq_lock);
444
445 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
446 if (IS_ERR(inode)) {
447 error = PTR_ERR(inode);
448 spin_lock(&mq_lock);
449 ipc_ns->mq_queues_count--;
450 goto out_unlock;
451 }
452
453 put_ipc_ns(ipc_ns);
454 dir->i_size += DIRENT_SIZE;
455 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
456
457 d_instantiate(dentry, inode);
458 dget(dentry);
459 return 0;
460out_unlock:
461 spin_unlock(&mq_lock);
462 if (ipc_ns)
463 put_ipc_ns(ipc_ns);
464 return error;
465}
466
467static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
468{
469 struct inode *inode = dentry->d_inode;
470
471 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
472 dir->i_size -= DIRENT_SIZE;
473 drop_nlink(inode);
474 dput(dentry);
475 return 0;
476}
477
478/*
479* This is routine for system read from queue file.
480* To avoid mess with doing here some sort of mq_receive we allow
481* to read only queue size & notification info (the only values
482* that are interesting from user point of view and aren't accessible
483* through std routines)
484*/
485static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
486 size_t count, loff_t *off)
487{
488 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
489 char buffer[FILENT_SIZE];
490 ssize_t ret;
491
492 spin_lock(&info->lock);
493 snprintf(buffer, sizeof(buffer),
494 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
495 info->qsize,
496 info->notify_owner ? info->notify.sigev_notify : 0,
497 (info->notify_owner &&
498 info->notify.sigev_notify == SIGEV_SIGNAL) ?
499 info->notify.sigev_signo : 0,
500 pid_vnr(info->notify_owner));
501 spin_unlock(&info->lock);
502 buffer[sizeof(buffer)-1] = '\0';
503
504 ret = simple_read_from_buffer(u_data, count, off, buffer,
505 strlen(buffer));
506 if (ret <= 0)
507 return ret;
508
509 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = CURRENT_TIME;
510 return ret;
511}
512
513static int mqueue_flush_file(struct file *filp, fl_owner_t id)
514{
515 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
516
517 spin_lock(&info->lock);
518 if (task_tgid(current) == info->notify_owner)
519 remove_notification(info);
520
521 spin_unlock(&info->lock);
522 return 0;
523}
524
525static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
526{
527 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
528 int retval = 0;
529
530 poll_wait(filp, &info->wait_q, poll_tab);
531
532 spin_lock(&info->lock);
533 if (info->attr.mq_curmsgs)
534 retval = POLLIN | POLLRDNORM;
535
536 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
537 retval |= POLLOUT | POLLWRNORM;
538 spin_unlock(&info->lock);
539
540 return retval;
541}
542
543/* Adds current to info->e_wait_q[sr] before element with smaller prio */
544static void wq_add(struct mqueue_inode_info *info, int sr,
545 struct ext_wait_queue *ewp)
546{
547 struct ext_wait_queue *walk;
548
549 ewp->task = current;
550
551 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
552 if (walk->task->static_prio <= current->static_prio) {
553 list_add_tail(&ewp->list, &walk->list);
554 return;
555 }
556 }
557 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
558}
559
560/*
561 * Puts current task to sleep. Caller must hold queue lock. After return
562 * lock isn't held.
563 * sr: SEND or RECV
564 */
565static int wq_sleep(struct mqueue_inode_info *info, int sr,
566 ktime_t *timeout, struct ext_wait_queue *ewp)
567{
568 int retval;
569 signed long time;
570
571 wq_add(info, sr, ewp);
572
573 for (;;) {
574 set_current_state(TASK_INTERRUPTIBLE);
575
576 spin_unlock(&info->lock);
577 time = schedule_hrtimeout_range_clock(timeout, 0,
578 HRTIMER_MODE_ABS, CLOCK_REALTIME);
579
580 while (ewp->state == STATE_PENDING)
581 cpu_relax();
582
583 if (ewp->state == STATE_READY) {
584 retval = 0;
585 goto out;
586 }
587 spin_lock(&info->lock);
588 if (ewp->state == STATE_READY) {
589 retval = 0;
590 goto out_unlock;
591 }
592 if (signal_pending(current)) {
593 retval = -ERESTARTSYS;
594 break;
595 }
596 if (time == 0) {
597 retval = -ETIMEDOUT;
598 break;
599 }
600 }
601 list_del(&ewp->list);
602out_unlock:
603 spin_unlock(&info->lock);
604out:
605 return retval;
606}
607
608/*
609 * Returns waiting task that should be serviced first or NULL if none exists
610 */
611static struct ext_wait_queue *wq_get_first_waiter(
612 struct mqueue_inode_info *info, int sr)
613{
614 struct list_head *ptr;
615
616 ptr = info->e_wait_q[sr].list.prev;
617 if (ptr == &info->e_wait_q[sr].list)
618 return NULL;
619 return list_entry(ptr, struct ext_wait_queue, list);
620}
621
622
623static inline void set_cookie(struct sk_buff *skb, char code)
624{
625 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
626}
627
628/*
629 * The next function is only to split too long sys_mq_timedsend
630 */
631static void __do_notify(struct mqueue_inode_info *info)
632{
633 /* notification
634 * invoked when there is registered process and there isn't process
635 * waiting synchronously for message AND state of queue changed from
636 * empty to not empty. Here we are sure that no one is waiting
637 * synchronously. */
638 if (info->notify_owner &&
639 info->attr.mq_curmsgs == 1) {
640 struct siginfo sig_i;
641 switch (info->notify.sigev_notify) {
642 case SIGEV_NONE:
643 break;
644 case SIGEV_SIGNAL:
645 /* sends signal */
646
647 sig_i.si_signo = info->notify.sigev_signo;
648 sig_i.si_errno = 0;
649 sig_i.si_code = SI_MESGQ;
650 sig_i.si_value = info->notify.sigev_value;
651 /* map current pid/uid into info->owner's namespaces */
652 rcu_read_lock();
653 sig_i.si_pid = task_tgid_nr_ns(current,
654 ns_of_pid(info->notify_owner));
655 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
656 rcu_read_unlock();
657
658 kill_pid_info(info->notify.sigev_signo,
659 &sig_i, info->notify_owner);
660 break;
661 case SIGEV_THREAD:
662 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
663 netlink_sendskb(info->notify_sock, info->notify_cookie);
664 break;
665 }
666 /* after notification unregisters process */
667 put_pid(info->notify_owner);
668 put_user_ns(info->notify_user_ns);
669 info->notify_owner = NULL;
670 info->notify_user_ns = NULL;
671 }
672 wake_up(&info->wait_q);
673}
674
675static int prepare_timeout(const struct timespec __user *u_abs_timeout,
676 ktime_t *expires, struct timespec *ts)
677{
678 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
679 return -EFAULT;
680 if (!timespec_valid(ts))
681 return -EINVAL;
682
683 *expires = timespec_to_ktime(*ts);
684 return 0;
685}
686
687static void remove_notification(struct mqueue_inode_info *info)
688{
689 if (info->notify_owner != NULL &&
690 info->notify.sigev_notify == SIGEV_THREAD) {
691 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
692 netlink_sendskb(info->notify_sock, info->notify_cookie);
693 }
694 put_pid(info->notify_owner);
695 put_user_ns(info->notify_user_ns);
696 info->notify_owner = NULL;
697 info->notify_user_ns = NULL;
698}
699
700static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
701{
702 int mq_treesize;
703 unsigned long total_size;
704
705 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
706 return -EINVAL;
707 if (capable(CAP_SYS_RESOURCE)) {
708 if (attr->mq_maxmsg > HARD_MSGMAX ||
709 attr->mq_msgsize > HARD_MSGSIZEMAX)
710 return -EINVAL;
711 } else {
712 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
713 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
714 return -EINVAL;
715 }
716 /* check for overflow */
717 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
718 return -EOVERFLOW;
719 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
720 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
721 sizeof(struct posix_msg_tree_node);
722 total_size = attr->mq_maxmsg * attr->mq_msgsize;
723 if (total_size + mq_treesize < total_size)
724 return -EOVERFLOW;
725 return 0;
726}
727
728/*
729 * Invoked when creating a new queue via sys_mq_open
730 */
731static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
732 struct path *path, int oflag, umode_t mode,
733 struct mq_attr *attr)
734{
735 const struct cred *cred = current_cred();
736 int ret;
737
738 if (attr) {
739 ret = mq_attr_ok(ipc_ns, attr);
740 if (ret)
741 return ERR_PTR(ret);
742 /* store for use during create */
743 path->dentry->d_fsdata = attr;
744 } else {
745 struct mq_attr def_attr;
746
747 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
748 ipc_ns->mq_msg_default);
749 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
750 ipc_ns->mq_msgsize_default);
751 ret = mq_attr_ok(ipc_ns, &def_attr);
752 if (ret)
753 return ERR_PTR(ret);
754 }
755
756 mode &= ~current_umask();
757 ret = vfs_create(dir, path->dentry, mode, true);
758 path->dentry->d_fsdata = NULL;
759 if (ret)
760 return ERR_PTR(ret);
761 return dentry_open(path, oflag, cred);
762}
763
764/* Opens existing queue */
765static struct file *do_open(struct path *path, int oflag)
766{
767 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
768 MAY_READ | MAY_WRITE };
769 int acc;
770 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
771 return ERR_PTR(-EINVAL);
772 acc = oflag2acc[oflag & O_ACCMODE];
773 if (inode_permission(path->dentry->d_inode, acc))
774 return ERR_PTR(-EACCES);
775 return dentry_open(path, oflag, current_cred());
776}
777
778SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
779 struct mq_attr __user *, u_attr)
780{
781 struct path path;
782 struct file *filp;
783 struct filename *name;
784 struct mq_attr attr;
785 int fd, error;
786 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
787 struct vfsmount *mnt = ipc_ns->mq_mnt;
788 struct dentry *root = mnt->mnt_root;
789 int ro;
790
791 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
792 return -EFAULT;
793
794 audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
795
796 if (IS_ERR(name = getname(u_name)))
797 return PTR_ERR(name);
798
799 fd = get_unused_fd_flags(O_CLOEXEC);
800 if (fd < 0)
801 goto out_putname;
802
803 ro = mnt_want_write(mnt); /* we'll drop it in any case */
804 error = 0;
805 mutex_lock(&root->d_inode->i_mutex);
806 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
807 if (IS_ERR(path.dentry)) {
808 error = PTR_ERR(path.dentry);
809 goto out_putfd;
810 }
811 path.mnt = mntget(mnt);
812
813 if (oflag & O_CREAT) {
814 if (path.dentry->d_inode) { /* entry already exists */
815 audit_inode(name, path.dentry, 0);
816 if (oflag & O_EXCL) {
817 error = -EEXIST;
818 goto out;
819 }
820 filp = do_open(&path, oflag);
821 } else {
822 if (ro) {
823 error = ro;
824 goto out;
825 }
826 audit_inode_parent_hidden(name, root);
827 filp = do_create(ipc_ns, root->d_inode,
828 &path, oflag, mode,
829 u_attr ? &attr : NULL);
830 }
831 } else {
832 if (!path.dentry->d_inode) {
833 error = -ENOENT;
834 goto out;
835 }
836 audit_inode(name, path.dentry, 0);
837 filp = do_open(&path, oflag);
838 }
839
840 if (!IS_ERR(filp))
841 fd_install(fd, filp);
842 else
843 error = PTR_ERR(filp);
844out:
845 path_put(&path);
846out_putfd:
847 if (error) {
848 put_unused_fd(fd);
849 fd = error;
850 }
851 mutex_unlock(&root->d_inode->i_mutex);
852 if (!ro)
853 mnt_drop_write(mnt);
854out_putname:
855 putname(name);
856 return fd;
857}
858
859SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
860{
861 int err;
862 struct filename *name;
863 struct dentry *dentry;
864 struct inode *inode = NULL;
865 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
866 struct vfsmount *mnt = ipc_ns->mq_mnt;
867
868 name = getname(u_name);
869 if (IS_ERR(name))
870 return PTR_ERR(name);
871
872 audit_inode_parent_hidden(name, mnt->mnt_root);
873 err = mnt_want_write(mnt);
874 if (err)
875 goto out_name;
876 mutex_lock_nested(&mnt->mnt_root->d_inode->i_mutex, I_MUTEX_PARENT);
877 dentry = lookup_one_len(name->name, mnt->mnt_root,
878 strlen(name->name));
879 if (IS_ERR(dentry)) {
880 err = PTR_ERR(dentry);
881 goto out_unlock;
882 }
883
884 inode = dentry->d_inode;
885 if (!inode) {
886 err = -ENOENT;
887 } else {
888 ihold(inode);
889 err = vfs_unlink(dentry->d_parent->d_inode, dentry, NULL);
890 }
891 dput(dentry);
892
893out_unlock:
894 mutex_unlock(&mnt->mnt_root->d_inode->i_mutex);
895 if (inode)
896 iput(inode);
897 mnt_drop_write(mnt);
898out_name:
899 putname(name);
900
901 return err;
902}
903
904/* Pipelined send and receive functions.
905 *
906 * If a receiver finds no waiting message, then it registers itself in the
907 * list of waiting receivers. A sender checks that list before adding the new
908 * message into the message array. If there is a waiting receiver, then it
909 * bypasses the message array and directly hands the message over to the
910 * receiver.
911 * The receiver accepts the message and returns without grabbing the queue
912 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
913 * are necessary. The same algorithm is used for sysv semaphores, see
914 * ipc/sem.c for more details.
915 *
916 * The same algorithm is used for senders.
917 */
918
919/* pipelined_send() - send a message directly to the task waiting in
920 * sys_mq_timedreceive() (without inserting message into a queue).
921 */
922static inline void pipelined_send(struct mqueue_inode_info *info,
923 struct msg_msg *message,
924 struct ext_wait_queue *receiver)
925{
926 receiver->msg = message;
927 list_del(&receiver->list);
928 receiver->state = STATE_PENDING;
929 wake_up_process(receiver->task);
930 smp_wmb();
931 receiver->state = STATE_READY;
932}
933
934/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
935 * gets its message and put to the queue (we have one free place for sure). */
936static inline void pipelined_receive(struct mqueue_inode_info *info)
937{
938 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
939
940 if (!sender) {
941 /* for poll */
942 wake_up_interruptible(&info->wait_q);
943 return;
944 }
945 if (msg_insert(sender->msg, info))
946 return;
947 list_del(&sender->list);
948 sender->state = STATE_PENDING;
949 wake_up_process(sender->task);
950 smp_wmb();
951 sender->state = STATE_READY;
952}
953
954SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
955 size_t, msg_len, unsigned int, msg_prio,
956 const struct timespec __user *, u_abs_timeout)
957{
958 struct fd f;
959 struct inode *inode;
960 struct ext_wait_queue wait;
961 struct ext_wait_queue *receiver;
962 struct msg_msg *msg_ptr;
963 struct mqueue_inode_info *info;
964 ktime_t expires, *timeout = NULL;
965 struct timespec ts;
966 struct posix_msg_tree_node *new_leaf = NULL;
967 int ret = 0;
968
969 if (u_abs_timeout) {
970 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
971 if (res)
972 return res;
973 timeout = &expires;
974 }
975
976 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
977 return -EINVAL;
978
979 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
980
981 f = fdget(mqdes);
982 if (unlikely(!f.file)) {
983 ret = -EBADF;
984 goto out;
985 }
986
987 inode = file_inode(f.file);
988 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
989 ret = -EBADF;
990 goto out_fput;
991 }
992 info = MQUEUE_I(inode);
993 audit_inode(NULL, f.file->f_path.dentry, 0);
994
995 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
996 ret = -EBADF;
997 goto out_fput;
998 }
999
1000 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1001 ret = -EMSGSIZE;
1002 goto out_fput;
1003 }
1004
1005 /* First try to allocate memory, before doing anything with
1006 * existing queues. */
1007 msg_ptr = load_msg(u_msg_ptr, msg_len);
1008 if (IS_ERR(msg_ptr)) {
1009 ret = PTR_ERR(msg_ptr);
1010 goto out_fput;
1011 }
1012 msg_ptr->m_ts = msg_len;
1013 msg_ptr->m_type = msg_prio;
1014
1015 /*
1016 * msg_insert really wants us to have a valid, spare node struct so
1017 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1018 * fall back to that if necessary.
1019 */
1020 if (!info->node_cache)
1021 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1022
1023 spin_lock(&info->lock);
1024
1025 if (!info->node_cache && new_leaf) {
1026 /* Save our speculative allocation into the cache */
1027 INIT_LIST_HEAD(&new_leaf->msg_list);
1028 info->node_cache = new_leaf;
1029 info->qsize += sizeof(*new_leaf);
1030 new_leaf = NULL;
1031 } else {
1032 kfree(new_leaf);
1033 }
1034
1035 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1036 if (f.file->f_flags & O_NONBLOCK) {
1037 ret = -EAGAIN;
1038 } else {
1039 wait.task = current;
1040 wait.msg = (void *) msg_ptr;
1041 wait.state = STATE_NONE;
1042 ret = wq_sleep(info, SEND, timeout, &wait);
1043 /*
1044 * wq_sleep must be called with info->lock held, and
1045 * returns with the lock released
1046 */
1047 goto out_free;
1048 }
1049 } else {
1050 receiver = wq_get_first_waiter(info, RECV);
1051 if (receiver) {
1052 pipelined_send(info, msg_ptr, receiver);
1053 } else {
1054 /* adds message to the queue */
1055 ret = msg_insert(msg_ptr, info);
1056 if (ret)
1057 goto out_unlock;
1058 __do_notify(info);
1059 }
1060 inode->i_atime = inode->i_mtime = inode->i_ctime =
1061 CURRENT_TIME;
1062 }
1063out_unlock:
1064 spin_unlock(&info->lock);
1065out_free:
1066 if (ret)
1067 free_msg(msg_ptr);
1068out_fput:
1069 fdput(f);
1070out:
1071 return ret;
1072}
1073
1074SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1075 size_t, msg_len, unsigned int __user *, u_msg_prio,
1076 const struct timespec __user *, u_abs_timeout)
1077{
1078 ssize_t ret;
1079 struct msg_msg *msg_ptr;
1080 struct fd f;
1081 struct inode *inode;
1082 struct mqueue_inode_info *info;
1083 struct ext_wait_queue wait;
1084 ktime_t expires, *timeout = NULL;
1085 struct timespec ts;
1086 struct posix_msg_tree_node *new_leaf = NULL;
1087
1088 if (u_abs_timeout) {
1089 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1090 if (res)
1091 return res;
1092 timeout = &expires;
1093 }
1094
1095 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1096
1097 f = fdget(mqdes);
1098 if (unlikely(!f.file)) {
1099 ret = -EBADF;
1100 goto out;
1101 }
1102
1103 inode = file_inode(f.file);
1104 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1105 ret = -EBADF;
1106 goto out_fput;
1107 }
1108 info = MQUEUE_I(inode);
1109 audit_inode(NULL, f.file->f_path.dentry, 0);
1110
1111 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1112 ret = -EBADF;
1113 goto out_fput;
1114 }
1115
1116 /* checks if buffer is big enough */
1117 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1118 ret = -EMSGSIZE;
1119 goto out_fput;
1120 }
1121
1122 /*
1123 * msg_insert really wants us to have a valid, spare node struct so
1124 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1125 * fall back to that if necessary.
1126 */
1127 if (!info->node_cache)
1128 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1129
1130 spin_lock(&info->lock);
1131
1132 if (!info->node_cache && new_leaf) {
1133 /* Save our speculative allocation into the cache */
1134 INIT_LIST_HEAD(&new_leaf->msg_list);
1135 info->node_cache = new_leaf;
1136 info->qsize += sizeof(*new_leaf);
1137 } else {
1138 kfree(new_leaf);
1139 }
1140
1141 if (info->attr.mq_curmsgs == 0) {
1142 if (f.file->f_flags & O_NONBLOCK) {
1143 spin_unlock(&info->lock);
1144 ret = -EAGAIN;
1145 } else {
1146 wait.task = current;
1147 wait.state = STATE_NONE;
1148 ret = wq_sleep(info, RECV, timeout, &wait);
1149 msg_ptr = wait.msg;
1150 }
1151 } else {
1152 msg_ptr = msg_get(info);
1153
1154 inode->i_atime = inode->i_mtime = inode->i_ctime =
1155 CURRENT_TIME;
1156
1157 /* There is now free space in queue. */
1158 pipelined_receive(info);
1159 spin_unlock(&info->lock);
1160 ret = 0;
1161 }
1162 if (ret == 0) {
1163 ret = msg_ptr->m_ts;
1164
1165 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1166 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1167 ret = -EFAULT;
1168 }
1169 free_msg(msg_ptr);
1170 }
1171out_fput:
1172 fdput(f);
1173out:
1174 return ret;
1175}
1176
1177/*
1178 * Notes: the case when user wants us to deregister (with NULL as pointer)
1179 * and he isn't currently owner of notification, will be silently discarded.
1180 * It isn't explicitly defined in the POSIX.
1181 */
1182SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1183 const struct sigevent __user *, u_notification)
1184{
1185 int ret;
1186 struct fd f;
1187 struct sock *sock;
1188 struct inode *inode;
1189 struct sigevent notification;
1190 struct mqueue_inode_info *info;
1191 struct sk_buff *nc;
1192
1193 if (u_notification) {
1194 if (copy_from_user(¬ification, u_notification,
1195 sizeof(struct sigevent)))
1196 return -EFAULT;
1197 }
1198
1199 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL);
1200
1201 nc = NULL;
1202 sock = NULL;
1203 if (u_notification != NULL) {
1204 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1205 notification.sigev_notify != SIGEV_SIGNAL &&
1206 notification.sigev_notify != SIGEV_THREAD))
1207 return -EINVAL;
1208 if (notification.sigev_notify == SIGEV_SIGNAL &&
1209 !valid_signal(notification.sigev_signo)) {
1210 return -EINVAL;
1211 }
1212 if (notification.sigev_notify == SIGEV_THREAD) {
1213 long timeo;
1214
1215 /* create the notify skb */
1216 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1217 if (!nc) {
1218 ret = -ENOMEM;
1219 goto out;
1220 }
1221 if (copy_from_user(nc->data,
1222 notification.sigev_value.sival_ptr,
1223 NOTIFY_COOKIE_LEN)) {
1224 ret = -EFAULT;
1225 goto out;
1226 }
1227
1228 /* TODO: add a header? */
1229 skb_put(nc, NOTIFY_COOKIE_LEN);
1230 /* and attach it to the socket */
1231retry:
1232 f = fdget(notification.sigev_signo);
1233 if (!f.file) {
1234 ret = -EBADF;
1235 goto out;
1236 }
1237 sock = netlink_getsockbyfilp(f.file);
1238 fdput(f);
1239 if (IS_ERR(sock)) {
1240 ret = PTR_ERR(sock);
1241 sock = NULL;
1242 goto out;
1243 }
1244
1245 timeo = MAX_SCHEDULE_TIMEOUT;
1246 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1247 if (ret == 1)
1248 goto retry;
1249 if (ret) {
1250 sock = NULL;
1251 nc = NULL;
1252 goto out;
1253 }
1254 }
1255 }
1256
1257 f = fdget(mqdes);
1258 if (!f.file) {
1259 ret = -EBADF;
1260 goto out;
1261 }
1262
1263 inode = file_inode(f.file);
1264 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1265 ret = -EBADF;
1266 goto out_fput;
1267 }
1268 info = MQUEUE_I(inode);
1269
1270 ret = 0;
1271 spin_lock(&info->lock);
1272 if (u_notification == NULL) {
1273 if (info->notify_owner == task_tgid(current)) {
1274 remove_notification(info);
1275 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1276 }
1277 } else if (info->notify_owner != NULL) {
1278 ret = -EBUSY;
1279 } else {
1280 switch (notification.sigev_notify) {
1281 case SIGEV_NONE:
1282 info->notify.sigev_notify = SIGEV_NONE;
1283 break;
1284 case SIGEV_THREAD:
1285 info->notify_sock = sock;
1286 info->notify_cookie = nc;
1287 sock = NULL;
1288 nc = NULL;
1289 info->notify.sigev_notify = SIGEV_THREAD;
1290 break;
1291 case SIGEV_SIGNAL:
1292 info->notify.sigev_signo = notification.sigev_signo;
1293 info->notify.sigev_value = notification.sigev_value;
1294 info->notify.sigev_notify = SIGEV_SIGNAL;
1295 break;
1296 }
1297
1298 info->notify_owner = get_pid(task_tgid(current));
1299 info->notify_user_ns = get_user_ns(current_user_ns());
1300 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1301 }
1302 spin_unlock(&info->lock);
1303out_fput:
1304 fdput(f);
1305out:
1306 if (sock)
1307 netlink_detachskb(sock, nc);
1308 else if (nc)
1309 dev_kfree_skb(nc);
1310
1311 return ret;
1312}
1313
1314SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1315 const struct mq_attr __user *, u_mqstat,
1316 struct mq_attr __user *, u_omqstat)
1317{
1318 int ret;
1319 struct mq_attr mqstat, omqstat;
1320 struct fd f;
1321 struct inode *inode;
1322 struct mqueue_inode_info *info;
1323
1324 if (u_mqstat != NULL) {
1325 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1326 return -EFAULT;
1327 if (mqstat.mq_flags & (~O_NONBLOCK))
1328 return -EINVAL;
1329 }
1330
1331 f = fdget(mqdes);
1332 if (!f.file) {
1333 ret = -EBADF;
1334 goto out;
1335 }
1336
1337 inode = file_inode(f.file);
1338 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1339 ret = -EBADF;
1340 goto out_fput;
1341 }
1342 info = MQUEUE_I(inode);
1343
1344 spin_lock(&info->lock);
1345
1346 omqstat = info->attr;
1347 omqstat.mq_flags = f.file->f_flags & O_NONBLOCK;
1348 if (u_mqstat) {
1349 audit_mq_getsetattr(mqdes, &mqstat);
1350 spin_lock(&f.file->f_lock);
1351 if (mqstat.mq_flags & O_NONBLOCK)
1352 f.file->f_flags |= O_NONBLOCK;
1353 else
1354 f.file->f_flags &= ~O_NONBLOCK;
1355 spin_unlock(&f.file->f_lock);
1356
1357 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1358 }
1359
1360 spin_unlock(&info->lock);
1361
1362 ret = 0;
1363 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1364 sizeof(struct mq_attr)))
1365 ret = -EFAULT;
1366
1367out_fput:
1368 fdput(f);
1369out:
1370 return ret;
1371}
1372
1373static const struct inode_operations mqueue_dir_inode_operations = {
1374 .lookup = simple_lookup,
1375 .create = mqueue_create,
1376 .unlink = mqueue_unlink,
1377};
1378
1379static const struct file_operations mqueue_file_operations = {
1380 .flush = mqueue_flush_file,
1381 .poll = mqueue_poll_file,
1382 .read = mqueue_read_file,
1383 .llseek = default_llseek,
1384};
1385
1386static const struct super_operations mqueue_super_ops = {
1387 .alloc_inode = mqueue_alloc_inode,
1388 .destroy_inode = mqueue_destroy_inode,
1389 .evict_inode = mqueue_evict_inode,
1390 .statfs = simple_statfs,
1391};
1392
1393static struct file_system_type mqueue_fs_type = {
1394 .name = "mqueue",
1395 .mount = mqueue_mount,
1396 .kill_sb = kill_litter_super,
1397 .fs_flags = FS_USERNS_MOUNT,
1398};
1399
1400int mq_init_ns(struct ipc_namespace *ns)
1401{
1402 ns->mq_queues_count = 0;
1403 ns->mq_queues_max = DFLT_QUEUESMAX;
1404 ns->mq_msg_max = DFLT_MSGMAX;
1405 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1406 ns->mq_msg_default = DFLT_MSG;
1407 ns->mq_msgsize_default = DFLT_MSGSIZE;
1408
1409 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1410 if (IS_ERR(ns->mq_mnt)) {
1411 int err = PTR_ERR(ns->mq_mnt);
1412 ns->mq_mnt = NULL;
1413 return err;
1414 }
1415 return 0;
1416}
1417
1418void mq_clear_sbinfo(struct ipc_namespace *ns)
1419{
1420 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1421}
1422
1423void mq_put_mnt(struct ipc_namespace *ns)
1424{
1425 kern_unmount(ns->mq_mnt);
1426}
1427
1428static int __init init_mqueue_fs(void)
1429{
1430 int error;
1431
1432 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1433 sizeof(struct mqueue_inode_info), 0,
1434 SLAB_HWCACHE_ALIGN, init_once);
1435 if (mqueue_inode_cachep == NULL)
1436 return -ENOMEM;
1437
1438 /* ignore failures - they are not fatal */
1439 mq_sysctl_table = mq_register_sysctl_table();
1440
1441 error = register_filesystem(&mqueue_fs_type);
1442 if (error)
1443 goto out_sysctl;
1444
1445 spin_lock_init(&mq_lock);
1446
1447 error = mq_init_ns(&init_ipc_ns);
1448 if (error)
1449 goto out_filesystem;
1450
1451 return 0;
1452
1453out_filesystem:
1454 unregister_filesystem(&mqueue_fs_type);
1455out_sysctl:
1456 if (mq_sysctl_table)
1457 unregister_sysctl_table(mq_sysctl_table);
1458 kmem_cache_destroy(mqueue_inode_cachep);
1459 return error;
1460}
1461
1462device_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/fs_context.h>
22#include <linux/namei.h>
23#include <linux/sysctl.h>
24#include <linux/poll.h>
25#include <linux/mqueue.h>
26#include <linux/msg.h>
27#include <linux/skbuff.h>
28#include <linux/vmalloc.h>
29#include <linux/netlink.h>
30#include <linux/syscalls.h>
31#include <linux/audit.h>
32#include <linux/signal.h>
33#include <linux/mutex.h>
34#include <linux/nsproxy.h>
35#include <linux/pid.h>
36#include <linux/ipc_namespace.h>
37#include <linux/user_namespace.h>
38#include <linux/slab.h>
39#include <linux/sched/wake_q.h>
40#include <linux/sched/signal.h>
41#include <linux/sched/user.h>
42
43#include <net/sock.h>
44#include "util.h"
45
46struct mqueue_fs_context {
47 struct ipc_namespace *ipc_ns;
48};
49
50#define MQUEUE_MAGIC 0x19800202
51#define DIRENT_SIZE 20
52#define FILENT_SIZE 80
53
54#define SEND 0
55#define RECV 1
56
57#define STATE_NONE 0
58#define STATE_READY 1
59
60struct posix_msg_tree_node {
61 struct rb_node rb_node;
62 struct list_head msg_list;
63 int priority;
64};
65
66struct ext_wait_queue { /* queue of sleeping tasks */
67 struct task_struct *task;
68 struct list_head list;
69 struct msg_msg *msg; /* ptr of loaded message */
70 int state; /* one of STATE_* values */
71};
72
73struct mqueue_inode_info {
74 spinlock_t lock;
75 struct inode vfs_inode;
76 wait_queue_head_t wait_q;
77
78 struct rb_root msg_tree;
79 struct rb_node *msg_tree_rightmost;
80 struct posix_msg_tree_node *node_cache;
81 struct mq_attr attr;
82
83 struct sigevent notify;
84 struct pid *notify_owner;
85 struct user_namespace *notify_user_ns;
86 struct user_struct *user; /* user who created, for accounting */
87 struct sock *notify_sock;
88 struct sk_buff *notify_cookie;
89
90 /* for tasks waiting for free space and messages, respectively */
91 struct ext_wait_queue e_wait_q[2];
92
93 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
94};
95
96static struct file_system_type mqueue_fs_type;
97static const struct inode_operations mqueue_dir_inode_operations;
98static const struct file_operations mqueue_file_operations;
99static const struct super_operations mqueue_super_ops;
100static const struct fs_context_operations mqueue_fs_context_ops;
101static void remove_notification(struct mqueue_inode_info *info);
102
103static struct kmem_cache *mqueue_inode_cachep;
104
105static struct ctl_table_header *mq_sysctl_table;
106
107static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
108{
109 return container_of(inode, struct mqueue_inode_info, vfs_inode);
110}
111
112/*
113 * This routine should be called with the mq_lock held.
114 */
115static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
116{
117 return get_ipc_ns(inode->i_sb->s_fs_info);
118}
119
120static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
121{
122 struct ipc_namespace *ns;
123
124 spin_lock(&mq_lock);
125 ns = __get_ns_from_inode(inode);
126 spin_unlock(&mq_lock);
127 return ns;
128}
129
130/* Auxiliary functions to manipulate messages' list */
131static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
132{
133 struct rb_node **p, *parent = NULL;
134 struct posix_msg_tree_node *leaf;
135 bool rightmost = true;
136
137 p = &info->msg_tree.rb_node;
138 while (*p) {
139 parent = *p;
140 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
141
142 if (likely(leaf->priority == msg->m_type))
143 goto insert_msg;
144 else if (msg->m_type < leaf->priority) {
145 p = &(*p)->rb_left;
146 rightmost = false;
147 } else
148 p = &(*p)->rb_right;
149 }
150 if (info->node_cache) {
151 leaf = info->node_cache;
152 info->node_cache = NULL;
153 } else {
154 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
155 if (!leaf)
156 return -ENOMEM;
157 INIT_LIST_HEAD(&leaf->msg_list);
158 }
159 leaf->priority = msg->m_type;
160
161 if (rightmost)
162 info->msg_tree_rightmost = &leaf->rb_node;
163
164 rb_link_node(&leaf->rb_node, parent, p);
165 rb_insert_color(&leaf->rb_node, &info->msg_tree);
166insert_msg:
167 info->attr.mq_curmsgs++;
168 info->qsize += msg->m_ts;
169 list_add_tail(&msg->m_list, &leaf->msg_list);
170 return 0;
171}
172
173static inline void msg_tree_erase(struct posix_msg_tree_node *leaf,
174 struct mqueue_inode_info *info)
175{
176 struct rb_node *node = &leaf->rb_node;
177
178 if (info->msg_tree_rightmost == node)
179 info->msg_tree_rightmost = rb_prev(node);
180
181 rb_erase(node, &info->msg_tree);
182 if (info->node_cache) {
183 kfree(leaf);
184 } else {
185 info->node_cache = leaf;
186 }
187}
188
189static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
190{
191 struct rb_node *parent = NULL;
192 struct posix_msg_tree_node *leaf;
193 struct msg_msg *msg;
194
195try_again:
196 /*
197 * During insert, low priorities go to the left and high to the
198 * right. On receive, we want the highest priorities first, so
199 * walk all the way to the right.
200 */
201 parent = info->msg_tree_rightmost;
202 if (!parent) {
203 if (info->attr.mq_curmsgs) {
204 pr_warn_once("Inconsistency in POSIX message queue, "
205 "no tree element, but supposedly messages "
206 "should exist!\n");
207 info->attr.mq_curmsgs = 0;
208 }
209 return NULL;
210 }
211 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
212 if (unlikely(list_empty(&leaf->msg_list))) {
213 pr_warn_once("Inconsistency in POSIX message queue, "
214 "empty leaf node but we haven't implemented "
215 "lazy leaf delete!\n");
216 msg_tree_erase(leaf, info);
217 goto try_again;
218 } else {
219 msg = list_first_entry(&leaf->msg_list,
220 struct msg_msg, m_list);
221 list_del(&msg->m_list);
222 if (list_empty(&leaf->msg_list)) {
223 msg_tree_erase(leaf, info);
224 }
225 }
226 info->attr.mq_curmsgs--;
227 info->qsize -= msg->m_ts;
228 return msg;
229}
230
231static struct inode *mqueue_get_inode(struct super_block *sb,
232 struct ipc_namespace *ipc_ns, umode_t mode,
233 struct mq_attr *attr)
234{
235 struct user_struct *u = current_user();
236 struct inode *inode;
237 int ret = -ENOMEM;
238
239 inode = new_inode(sb);
240 if (!inode)
241 goto err;
242
243 inode->i_ino = get_next_ino();
244 inode->i_mode = mode;
245 inode->i_uid = current_fsuid();
246 inode->i_gid = current_fsgid();
247 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
248
249 if (S_ISREG(mode)) {
250 struct mqueue_inode_info *info;
251 unsigned long mq_bytes, mq_treesize;
252
253 inode->i_fop = &mqueue_file_operations;
254 inode->i_size = FILENT_SIZE;
255 /* mqueue specific info */
256 info = MQUEUE_I(inode);
257 spin_lock_init(&info->lock);
258 init_waitqueue_head(&info->wait_q);
259 INIT_LIST_HEAD(&info->e_wait_q[0].list);
260 INIT_LIST_HEAD(&info->e_wait_q[1].list);
261 info->notify_owner = NULL;
262 info->notify_user_ns = NULL;
263 info->qsize = 0;
264 info->user = NULL; /* set when all is ok */
265 info->msg_tree = RB_ROOT;
266 info->msg_tree_rightmost = NULL;
267 info->node_cache = NULL;
268 memset(&info->attr, 0, sizeof(info->attr));
269 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
270 ipc_ns->mq_msg_default);
271 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
272 ipc_ns->mq_msgsize_default);
273 if (attr) {
274 info->attr.mq_maxmsg = attr->mq_maxmsg;
275 info->attr.mq_msgsize = attr->mq_msgsize;
276 }
277 /*
278 * We used to allocate a static array of pointers and account
279 * the size of that array as well as one msg_msg struct per
280 * possible message into the queue size. That's no longer
281 * accurate as the queue is now an rbtree and will grow and
282 * shrink depending on usage patterns. We can, however, still
283 * account one msg_msg struct per message, but the nodes are
284 * allocated depending on priority usage, and most programs
285 * only use one, or a handful, of priorities. However, since
286 * this is pinned memory, we need to assume worst case, so
287 * that means the min(mq_maxmsg, max_priorities) * struct
288 * posix_msg_tree_node.
289 */
290
291 ret = -EINVAL;
292 if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
293 goto out_inode;
294 if (capable(CAP_SYS_RESOURCE)) {
295 if (info->attr.mq_maxmsg > HARD_MSGMAX ||
296 info->attr.mq_msgsize > HARD_MSGSIZEMAX)
297 goto out_inode;
298 } else {
299 if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
300 info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
301 goto out_inode;
302 }
303 ret = -EOVERFLOW;
304 /* check for overflow */
305 if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
306 goto out_inode;
307 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
308 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
309 sizeof(struct posix_msg_tree_node);
310 mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
311 if (mq_bytes + mq_treesize < mq_bytes)
312 goto out_inode;
313 mq_bytes += mq_treesize;
314 spin_lock(&mq_lock);
315 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
316 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
317 spin_unlock(&mq_lock);
318 /* mqueue_evict_inode() releases info->messages */
319 ret = -EMFILE;
320 goto out_inode;
321 }
322 u->mq_bytes += mq_bytes;
323 spin_unlock(&mq_lock);
324
325 /* all is ok */
326 info->user = get_uid(u);
327 } else if (S_ISDIR(mode)) {
328 inc_nlink(inode);
329 /* Some things misbehave if size == 0 on a directory */
330 inode->i_size = 2 * DIRENT_SIZE;
331 inode->i_op = &mqueue_dir_inode_operations;
332 inode->i_fop = &simple_dir_operations;
333 }
334
335 return inode;
336out_inode:
337 iput(inode);
338err:
339 return ERR_PTR(ret);
340}
341
342static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc)
343{
344 struct inode *inode;
345 struct ipc_namespace *ns = sb->s_fs_info;
346
347 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
348 sb->s_blocksize = PAGE_SIZE;
349 sb->s_blocksize_bits = PAGE_SHIFT;
350 sb->s_magic = MQUEUE_MAGIC;
351 sb->s_op = &mqueue_super_ops;
352
353 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
354 if (IS_ERR(inode))
355 return PTR_ERR(inode);
356
357 sb->s_root = d_make_root(inode);
358 if (!sb->s_root)
359 return -ENOMEM;
360 return 0;
361}
362
363static int mqueue_get_tree(struct fs_context *fc)
364{
365 struct mqueue_fs_context *ctx = fc->fs_private;
366
367 return get_tree_keyed(fc, mqueue_fill_super, ctx->ipc_ns);
368}
369
370static void mqueue_fs_context_free(struct fs_context *fc)
371{
372 struct mqueue_fs_context *ctx = fc->fs_private;
373
374 put_ipc_ns(ctx->ipc_ns);
375 kfree(ctx);
376}
377
378static int mqueue_init_fs_context(struct fs_context *fc)
379{
380 struct mqueue_fs_context *ctx;
381
382 ctx = kzalloc(sizeof(struct mqueue_fs_context), GFP_KERNEL);
383 if (!ctx)
384 return -ENOMEM;
385
386 ctx->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
387 put_user_ns(fc->user_ns);
388 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
389 fc->fs_private = ctx;
390 fc->ops = &mqueue_fs_context_ops;
391 return 0;
392}
393
394static struct vfsmount *mq_create_mount(struct ipc_namespace *ns)
395{
396 struct mqueue_fs_context *ctx;
397 struct fs_context *fc;
398 struct vfsmount *mnt;
399
400 fc = fs_context_for_mount(&mqueue_fs_type, SB_KERNMOUNT);
401 if (IS_ERR(fc))
402 return ERR_CAST(fc);
403
404 ctx = fc->fs_private;
405 put_ipc_ns(ctx->ipc_ns);
406 ctx->ipc_ns = get_ipc_ns(ns);
407 put_user_ns(fc->user_ns);
408 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
409
410 mnt = fc_mount(fc);
411 put_fs_context(fc);
412 return mnt;
413}
414
415static void init_once(void *foo)
416{
417 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
418
419 inode_init_once(&p->vfs_inode);
420}
421
422static struct inode *mqueue_alloc_inode(struct super_block *sb)
423{
424 struct mqueue_inode_info *ei;
425
426 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
427 if (!ei)
428 return NULL;
429 return &ei->vfs_inode;
430}
431
432static void mqueue_free_inode(struct inode *inode)
433{
434 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
435}
436
437static void mqueue_evict_inode(struct inode *inode)
438{
439 struct mqueue_inode_info *info;
440 struct user_struct *user;
441 struct ipc_namespace *ipc_ns;
442 struct msg_msg *msg, *nmsg;
443 LIST_HEAD(tmp_msg);
444
445 clear_inode(inode);
446
447 if (S_ISDIR(inode->i_mode))
448 return;
449
450 ipc_ns = get_ns_from_inode(inode);
451 info = MQUEUE_I(inode);
452 spin_lock(&info->lock);
453 while ((msg = msg_get(info)) != NULL)
454 list_add_tail(&msg->m_list, &tmp_msg);
455 kfree(info->node_cache);
456 spin_unlock(&info->lock);
457
458 list_for_each_entry_safe(msg, nmsg, &tmp_msg, m_list) {
459 list_del(&msg->m_list);
460 free_msg(msg);
461 }
462
463 user = info->user;
464 if (user) {
465 unsigned long mq_bytes, mq_treesize;
466
467 /* Total amount of bytes accounted for the mqueue */
468 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
469 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
470 sizeof(struct posix_msg_tree_node);
471
472 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
473 info->attr.mq_msgsize);
474
475 spin_lock(&mq_lock);
476 user->mq_bytes -= mq_bytes;
477 /*
478 * get_ns_from_inode() ensures that the
479 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
480 * to which we now hold a reference, or it is NULL.
481 * We can't put it here under mq_lock, though.
482 */
483 if (ipc_ns)
484 ipc_ns->mq_queues_count--;
485 spin_unlock(&mq_lock);
486 free_uid(user);
487 }
488 if (ipc_ns)
489 put_ipc_ns(ipc_ns);
490}
491
492static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
493{
494 struct inode *dir = dentry->d_parent->d_inode;
495 struct inode *inode;
496 struct mq_attr *attr = arg;
497 int error;
498 struct ipc_namespace *ipc_ns;
499
500 spin_lock(&mq_lock);
501 ipc_ns = __get_ns_from_inode(dir);
502 if (!ipc_ns) {
503 error = -EACCES;
504 goto out_unlock;
505 }
506
507 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
508 !capable(CAP_SYS_RESOURCE)) {
509 error = -ENOSPC;
510 goto out_unlock;
511 }
512 ipc_ns->mq_queues_count++;
513 spin_unlock(&mq_lock);
514
515 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
516 if (IS_ERR(inode)) {
517 error = PTR_ERR(inode);
518 spin_lock(&mq_lock);
519 ipc_ns->mq_queues_count--;
520 goto out_unlock;
521 }
522
523 put_ipc_ns(ipc_ns);
524 dir->i_size += DIRENT_SIZE;
525 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
526
527 d_instantiate(dentry, inode);
528 dget(dentry);
529 return 0;
530out_unlock:
531 spin_unlock(&mq_lock);
532 if (ipc_ns)
533 put_ipc_ns(ipc_ns);
534 return error;
535}
536
537static int mqueue_create(struct inode *dir, struct dentry *dentry,
538 umode_t mode, bool excl)
539{
540 return mqueue_create_attr(dentry, mode, NULL);
541}
542
543static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
544{
545 struct inode *inode = d_inode(dentry);
546
547 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
548 dir->i_size -= DIRENT_SIZE;
549 drop_nlink(inode);
550 dput(dentry);
551 return 0;
552}
553
554/*
555* This is routine for system read from queue file.
556* To avoid mess with doing here some sort of mq_receive we allow
557* to read only queue size & notification info (the only values
558* that are interesting from user point of view and aren't accessible
559* through std routines)
560*/
561static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
562 size_t count, loff_t *off)
563{
564 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
565 char buffer[FILENT_SIZE];
566 ssize_t ret;
567
568 spin_lock(&info->lock);
569 snprintf(buffer, sizeof(buffer),
570 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
571 info->qsize,
572 info->notify_owner ? info->notify.sigev_notify : 0,
573 (info->notify_owner &&
574 info->notify.sigev_notify == SIGEV_SIGNAL) ?
575 info->notify.sigev_signo : 0,
576 pid_vnr(info->notify_owner));
577 spin_unlock(&info->lock);
578 buffer[sizeof(buffer)-1] = '\0';
579
580 ret = simple_read_from_buffer(u_data, count, off, buffer,
581 strlen(buffer));
582 if (ret <= 0)
583 return ret;
584
585 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
586 return ret;
587}
588
589static int mqueue_flush_file(struct file *filp, fl_owner_t id)
590{
591 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
592
593 spin_lock(&info->lock);
594 if (task_tgid(current) == info->notify_owner)
595 remove_notification(info);
596
597 spin_unlock(&info->lock);
598 return 0;
599}
600
601static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
602{
603 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
604 __poll_t retval = 0;
605
606 poll_wait(filp, &info->wait_q, poll_tab);
607
608 spin_lock(&info->lock);
609 if (info->attr.mq_curmsgs)
610 retval = EPOLLIN | EPOLLRDNORM;
611
612 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
613 retval |= EPOLLOUT | EPOLLWRNORM;
614 spin_unlock(&info->lock);
615
616 return retval;
617}
618
619/* Adds current to info->e_wait_q[sr] before element with smaller prio */
620static void wq_add(struct mqueue_inode_info *info, int sr,
621 struct ext_wait_queue *ewp)
622{
623 struct ext_wait_queue *walk;
624
625 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
626 if (walk->task->prio <= current->prio) {
627 list_add_tail(&ewp->list, &walk->list);
628 return;
629 }
630 }
631 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
632}
633
634/*
635 * Puts current task to sleep. Caller must hold queue lock. After return
636 * lock isn't held.
637 * sr: SEND or RECV
638 */
639static int wq_sleep(struct mqueue_inode_info *info, int sr,
640 ktime_t *timeout, struct ext_wait_queue *ewp)
641 __releases(&info->lock)
642{
643 int retval;
644 signed long time;
645
646 wq_add(info, sr, ewp);
647
648 for (;;) {
649 __set_current_state(TASK_INTERRUPTIBLE);
650
651 spin_unlock(&info->lock);
652 time = schedule_hrtimeout_range_clock(timeout, 0,
653 HRTIMER_MODE_ABS, CLOCK_REALTIME);
654
655 if (ewp->state == STATE_READY) {
656 retval = 0;
657 goto out;
658 }
659 spin_lock(&info->lock);
660 if (ewp->state == STATE_READY) {
661 retval = 0;
662 goto out_unlock;
663 }
664 if (signal_pending(current)) {
665 retval = -ERESTARTSYS;
666 break;
667 }
668 if (time == 0) {
669 retval = -ETIMEDOUT;
670 break;
671 }
672 }
673 list_del(&ewp->list);
674out_unlock:
675 spin_unlock(&info->lock);
676out:
677 return retval;
678}
679
680/*
681 * Returns waiting task that should be serviced first or NULL if none exists
682 */
683static struct ext_wait_queue *wq_get_first_waiter(
684 struct mqueue_inode_info *info, int sr)
685{
686 struct list_head *ptr;
687
688 ptr = info->e_wait_q[sr].list.prev;
689 if (ptr == &info->e_wait_q[sr].list)
690 return NULL;
691 return list_entry(ptr, struct ext_wait_queue, list);
692}
693
694
695static inline void set_cookie(struct sk_buff *skb, char code)
696{
697 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
698}
699
700/*
701 * The next function is only to split too long sys_mq_timedsend
702 */
703static void __do_notify(struct mqueue_inode_info *info)
704{
705 /* notification
706 * invoked when there is registered process and there isn't process
707 * waiting synchronously for message AND state of queue changed from
708 * empty to not empty. Here we are sure that no one is waiting
709 * synchronously. */
710 if (info->notify_owner &&
711 info->attr.mq_curmsgs == 1) {
712 struct kernel_siginfo sig_i;
713 switch (info->notify.sigev_notify) {
714 case SIGEV_NONE:
715 break;
716 case SIGEV_SIGNAL:
717 /* sends signal */
718
719 clear_siginfo(&sig_i);
720 sig_i.si_signo = info->notify.sigev_signo;
721 sig_i.si_errno = 0;
722 sig_i.si_code = SI_MESGQ;
723 sig_i.si_value = info->notify.sigev_value;
724 /* map current pid/uid into info->owner's namespaces */
725 rcu_read_lock();
726 sig_i.si_pid = task_tgid_nr_ns(current,
727 ns_of_pid(info->notify_owner));
728 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
729 rcu_read_unlock();
730
731 kill_pid_info(info->notify.sigev_signo,
732 &sig_i, info->notify_owner);
733 break;
734 case SIGEV_THREAD:
735 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
736 netlink_sendskb(info->notify_sock, info->notify_cookie);
737 break;
738 }
739 /* after notification unregisters process */
740 put_pid(info->notify_owner);
741 put_user_ns(info->notify_user_ns);
742 info->notify_owner = NULL;
743 info->notify_user_ns = NULL;
744 }
745 wake_up(&info->wait_q);
746}
747
748static int prepare_timeout(const struct __kernel_timespec __user *u_abs_timeout,
749 struct timespec64 *ts)
750{
751 if (get_timespec64(ts, u_abs_timeout))
752 return -EFAULT;
753 if (!timespec64_valid(ts))
754 return -EINVAL;
755 return 0;
756}
757
758static void remove_notification(struct mqueue_inode_info *info)
759{
760 if (info->notify_owner != NULL &&
761 info->notify.sigev_notify == SIGEV_THREAD) {
762 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
763 netlink_sendskb(info->notify_sock, info->notify_cookie);
764 }
765 put_pid(info->notify_owner);
766 put_user_ns(info->notify_user_ns);
767 info->notify_owner = NULL;
768 info->notify_user_ns = NULL;
769}
770
771static int prepare_open(struct dentry *dentry, int oflag, int ro,
772 umode_t mode, struct filename *name,
773 struct mq_attr *attr)
774{
775 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
776 MAY_READ | MAY_WRITE };
777 int acc;
778
779 if (d_really_is_negative(dentry)) {
780 if (!(oflag & O_CREAT))
781 return -ENOENT;
782 if (ro)
783 return ro;
784 audit_inode_parent_hidden(name, dentry->d_parent);
785 return vfs_mkobj(dentry, mode & ~current_umask(),
786 mqueue_create_attr, attr);
787 }
788 /* it already existed */
789 audit_inode(name, dentry, 0);
790 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
791 return -EEXIST;
792 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
793 return -EINVAL;
794 acc = oflag2acc[oflag & O_ACCMODE];
795 return inode_permission(d_inode(dentry), acc);
796}
797
798static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
799 struct mq_attr *attr)
800{
801 struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
802 struct dentry *root = mnt->mnt_root;
803 struct filename *name;
804 struct path path;
805 int fd, error;
806 int ro;
807
808 audit_mq_open(oflag, mode, attr);
809
810 if (IS_ERR(name = getname(u_name)))
811 return PTR_ERR(name);
812
813 fd = get_unused_fd_flags(O_CLOEXEC);
814 if (fd < 0)
815 goto out_putname;
816
817 ro = mnt_want_write(mnt); /* we'll drop it in any case */
818 inode_lock(d_inode(root));
819 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
820 if (IS_ERR(path.dentry)) {
821 error = PTR_ERR(path.dentry);
822 goto out_putfd;
823 }
824 path.mnt = mntget(mnt);
825 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
826 if (!error) {
827 struct file *file = dentry_open(&path, oflag, current_cred());
828 if (!IS_ERR(file))
829 fd_install(fd, file);
830 else
831 error = PTR_ERR(file);
832 }
833 path_put(&path);
834out_putfd:
835 if (error) {
836 put_unused_fd(fd);
837 fd = error;
838 }
839 inode_unlock(d_inode(root));
840 if (!ro)
841 mnt_drop_write(mnt);
842out_putname:
843 putname(name);
844 return fd;
845}
846
847SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
848 struct mq_attr __user *, u_attr)
849{
850 struct mq_attr attr;
851 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
852 return -EFAULT;
853
854 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
855}
856
857SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
858{
859 int err;
860 struct filename *name;
861 struct dentry *dentry;
862 struct inode *inode = NULL;
863 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
864 struct vfsmount *mnt = ipc_ns->mq_mnt;
865
866 name = getname(u_name);
867 if (IS_ERR(name))
868 return PTR_ERR(name);
869
870 audit_inode_parent_hidden(name, mnt->mnt_root);
871 err = mnt_want_write(mnt);
872 if (err)
873 goto out_name;
874 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
875 dentry = lookup_one_len(name->name, mnt->mnt_root,
876 strlen(name->name));
877 if (IS_ERR(dentry)) {
878 err = PTR_ERR(dentry);
879 goto out_unlock;
880 }
881
882 inode = d_inode(dentry);
883 if (!inode) {
884 err = -ENOENT;
885 } else {
886 ihold(inode);
887 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
888 }
889 dput(dentry);
890
891out_unlock:
892 inode_unlock(d_inode(mnt->mnt_root));
893 if (inode)
894 iput(inode);
895 mnt_drop_write(mnt);
896out_name:
897 putname(name);
898
899 return err;
900}
901
902/* Pipelined send and receive functions.
903 *
904 * If a receiver finds no waiting message, then it registers itself in the
905 * list of waiting receivers. A sender checks that list before adding the new
906 * message into the message array. If there is a waiting receiver, then it
907 * bypasses the message array and directly hands the message over to the
908 * receiver. The receiver accepts the message and returns without grabbing the
909 * queue spinlock:
910 *
911 * - Set pointer to message.
912 * - Queue the receiver task for later wakeup (without the info->lock).
913 * - Update its state to STATE_READY. Now the receiver can continue.
914 * - Wake up the process after the lock is dropped. Should the process wake up
915 * before this wakeup (due to a timeout or a signal) it will either see
916 * STATE_READY and continue or acquire the lock to check the state again.
917 *
918 * The same algorithm is used for senders.
919 */
920
921/* pipelined_send() - send a message directly to the task waiting in
922 * sys_mq_timedreceive() (without inserting message into a queue).
923 */
924static inline void pipelined_send(struct wake_q_head *wake_q,
925 struct mqueue_inode_info *info,
926 struct msg_msg *message,
927 struct ext_wait_queue *receiver)
928{
929 receiver->msg = message;
930 list_del(&receiver->list);
931 wake_q_add(wake_q, receiver->task);
932 /*
933 * Rely on the implicit cmpxchg barrier from wake_q_add such
934 * that we can ensure that updating receiver->state is the last
935 * write operation: As once set, the receiver can continue,
936 * and if we don't have the reference count from the wake_q,
937 * yet, at that point we can later have a use-after-free
938 * condition and bogus wakeup.
939 */
940 receiver->state = STATE_READY;
941}
942
943/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
944 * gets its message and put to the queue (we have one free place for sure). */
945static inline void pipelined_receive(struct wake_q_head *wake_q,
946 struct mqueue_inode_info *info)
947{
948 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
949
950 if (!sender) {
951 /* for poll */
952 wake_up_interruptible(&info->wait_q);
953 return;
954 }
955 if (msg_insert(sender->msg, info))
956 return;
957
958 list_del(&sender->list);
959 wake_q_add(wake_q, sender->task);
960 sender->state = STATE_READY;
961}
962
963static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
964 size_t msg_len, unsigned int msg_prio,
965 struct timespec64 *ts)
966{
967 struct fd f;
968 struct inode *inode;
969 struct ext_wait_queue wait;
970 struct ext_wait_queue *receiver;
971 struct msg_msg *msg_ptr;
972 struct mqueue_inode_info *info;
973 ktime_t expires, *timeout = NULL;
974 struct posix_msg_tree_node *new_leaf = NULL;
975 int ret = 0;
976 DEFINE_WAKE_Q(wake_q);
977
978 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
979 return -EINVAL;
980
981 if (ts) {
982 expires = timespec64_to_ktime(*ts);
983 timeout = &expires;
984 }
985
986 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
987
988 f = fdget(mqdes);
989 if (unlikely(!f.file)) {
990 ret = -EBADF;
991 goto out;
992 }
993
994 inode = file_inode(f.file);
995 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
996 ret = -EBADF;
997 goto out_fput;
998 }
999 info = MQUEUE_I(inode);
1000 audit_file(f.file);
1001
1002 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
1003 ret = -EBADF;
1004 goto out_fput;
1005 }
1006
1007 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1008 ret = -EMSGSIZE;
1009 goto out_fput;
1010 }
1011
1012 /* First try to allocate memory, before doing anything with
1013 * existing queues. */
1014 msg_ptr = load_msg(u_msg_ptr, msg_len);
1015 if (IS_ERR(msg_ptr)) {
1016 ret = PTR_ERR(msg_ptr);
1017 goto out_fput;
1018 }
1019 msg_ptr->m_ts = msg_len;
1020 msg_ptr->m_type = msg_prio;
1021
1022 /*
1023 * msg_insert really wants us to have a valid, spare node struct so
1024 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1025 * fall back to that if necessary.
1026 */
1027 if (!info->node_cache)
1028 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1029
1030 spin_lock(&info->lock);
1031
1032 if (!info->node_cache && new_leaf) {
1033 /* Save our speculative allocation into the cache */
1034 INIT_LIST_HEAD(&new_leaf->msg_list);
1035 info->node_cache = new_leaf;
1036 new_leaf = NULL;
1037 } else {
1038 kfree(new_leaf);
1039 }
1040
1041 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1042 if (f.file->f_flags & O_NONBLOCK) {
1043 ret = -EAGAIN;
1044 } else {
1045 wait.task = current;
1046 wait.msg = (void *) msg_ptr;
1047 wait.state = STATE_NONE;
1048 ret = wq_sleep(info, SEND, timeout, &wait);
1049 /*
1050 * wq_sleep must be called with info->lock held, and
1051 * returns with the lock released
1052 */
1053 goto out_free;
1054 }
1055 } else {
1056 receiver = wq_get_first_waiter(info, RECV);
1057 if (receiver) {
1058 pipelined_send(&wake_q, info, msg_ptr, receiver);
1059 } else {
1060 /* adds message to the queue */
1061 ret = msg_insert(msg_ptr, info);
1062 if (ret)
1063 goto out_unlock;
1064 __do_notify(info);
1065 }
1066 inode->i_atime = inode->i_mtime = inode->i_ctime =
1067 current_time(inode);
1068 }
1069out_unlock:
1070 spin_unlock(&info->lock);
1071 wake_up_q(&wake_q);
1072out_free:
1073 if (ret)
1074 free_msg(msg_ptr);
1075out_fput:
1076 fdput(f);
1077out:
1078 return ret;
1079}
1080
1081static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1082 size_t msg_len, unsigned int __user *u_msg_prio,
1083 struct timespec64 *ts)
1084{
1085 ssize_t ret;
1086 struct msg_msg *msg_ptr;
1087 struct fd f;
1088 struct inode *inode;
1089 struct mqueue_inode_info *info;
1090 struct ext_wait_queue wait;
1091 ktime_t expires, *timeout = NULL;
1092 struct posix_msg_tree_node *new_leaf = NULL;
1093
1094 if (ts) {
1095 expires = timespec64_to_ktime(*ts);
1096 timeout = &expires;
1097 }
1098
1099 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1100
1101 f = fdget(mqdes);
1102 if (unlikely(!f.file)) {
1103 ret = -EBADF;
1104 goto out;
1105 }
1106
1107 inode = file_inode(f.file);
1108 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1109 ret = -EBADF;
1110 goto out_fput;
1111 }
1112 info = MQUEUE_I(inode);
1113 audit_file(f.file);
1114
1115 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1116 ret = -EBADF;
1117 goto out_fput;
1118 }
1119
1120 /* checks if buffer is big enough */
1121 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1122 ret = -EMSGSIZE;
1123 goto out_fput;
1124 }
1125
1126 /*
1127 * msg_insert really wants us to have a valid, spare node struct so
1128 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1129 * fall back to that if necessary.
1130 */
1131 if (!info->node_cache)
1132 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1133
1134 spin_lock(&info->lock);
1135
1136 if (!info->node_cache && new_leaf) {
1137 /* Save our speculative allocation into the cache */
1138 INIT_LIST_HEAD(&new_leaf->msg_list);
1139 info->node_cache = new_leaf;
1140 } else {
1141 kfree(new_leaf);
1142 }
1143
1144 if (info->attr.mq_curmsgs == 0) {
1145 if (f.file->f_flags & O_NONBLOCK) {
1146 spin_unlock(&info->lock);
1147 ret = -EAGAIN;
1148 } else {
1149 wait.task = current;
1150 wait.state = STATE_NONE;
1151 ret = wq_sleep(info, RECV, timeout, &wait);
1152 msg_ptr = wait.msg;
1153 }
1154 } else {
1155 DEFINE_WAKE_Q(wake_q);
1156
1157 msg_ptr = msg_get(info);
1158
1159 inode->i_atime = inode->i_mtime = inode->i_ctime =
1160 current_time(inode);
1161
1162 /* There is now free space in queue. */
1163 pipelined_receive(&wake_q, info);
1164 spin_unlock(&info->lock);
1165 wake_up_q(&wake_q);
1166 ret = 0;
1167 }
1168 if (ret == 0) {
1169 ret = msg_ptr->m_ts;
1170
1171 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1172 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1173 ret = -EFAULT;
1174 }
1175 free_msg(msg_ptr);
1176 }
1177out_fput:
1178 fdput(f);
1179out:
1180 return ret;
1181}
1182
1183SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1184 size_t, msg_len, unsigned int, msg_prio,
1185 const struct __kernel_timespec __user *, u_abs_timeout)
1186{
1187 struct timespec64 ts, *p = NULL;
1188 if (u_abs_timeout) {
1189 int res = prepare_timeout(u_abs_timeout, &ts);
1190 if (res)
1191 return res;
1192 p = &ts;
1193 }
1194 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1195}
1196
1197SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1198 size_t, msg_len, unsigned int __user *, u_msg_prio,
1199 const struct __kernel_timespec __user *, u_abs_timeout)
1200{
1201 struct timespec64 ts, *p = NULL;
1202 if (u_abs_timeout) {
1203 int res = prepare_timeout(u_abs_timeout, &ts);
1204 if (res)
1205 return res;
1206 p = &ts;
1207 }
1208 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1209}
1210
1211/*
1212 * Notes: the case when user wants us to deregister (with NULL as pointer)
1213 * and he isn't currently owner of notification, will be silently discarded.
1214 * It isn't explicitly defined in the POSIX.
1215 */
1216static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1217{
1218 int ret;
1219 struct fd f;
1220 struct sock *sock;
1221 struct inode *inode;
1222 struct mqueue_inode_info *info;
1223 struct sk_buff *nc;
1224
1225 audit_mq_notify(mqdes, notification);
1226
1227 nc = NULL;
1228 sock = NULL;
1229 if (notification != NULL) {
1230 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1231 notification->sigev_notify != SIGEV_SIGNAL &&
1232 notification->sigev_notify != SIGEV_THREAD))
1233 return -EINVAL;
1234 if (notification->sigev_notify == SIGEV_SIGNAL &&
1235 !valid_signal(notification->sigev_signo)) {
1236 return -EINVAL;
1237 }
1238 if (notification->sigev_notify == SIGEV_THREAD) {
1239 long timeo;
1240
1241 /* create the notify skb */
1242 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1243 if (!nc)
1244 return -ENOMEM;
1245
1246 if (copy_from_user(nc->data,
1247 notification->sigev_value.sival_ptr,
1248 NOTIFY_COOKIE_LEN)) {
1249 ret = -EFAULT;
1250 goto free_skb;
1251 }
1252
1253 /* TODO: add a header? */
1254 skb_put(nc, NOTIFY_COOKIE_LEN);
1255 /* and attach it to the socket */
1256retry:
1257 f = fdget(notification->sigev_signo);
1258 if (!f.file) {
1259 ret = -EBADF;
1260 goto out;
1261 }
1262 sock = netlink_getsockbyfilp(f.file);
1263 fdput(f);
1264 if (IS_ERR(sock)) {
1265 ret = PTR_ERR(sock);
1266 goto free_skb;
1267 }
1268
1269 timeo = MAX_SCHEDULE_TIMEOUT;
1270 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1271 if (ret == 1) {
1272 sock = NULL;
1273 goto retry;
1274 }
1275 if (ret)
1276 return ret;
1277 }
1278 }
1279
1280 f = fdget(mqdes);
1281 if (!f.file) {
1282 ret = -EBADF;
1283 goto out;
1284 }
1285
1286 inode = file_inode(f.file);
1287 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1288 ret = -EBADF;
1289 goto out_fput;
1290 }
1291 info = MQUEUE_I(inode);
1292
1293 ret = 0;
1294 spin_lock(&info->lock);
1295 if (notification == NULL) {
1296 if (info->notify_owner == task_tgid(current)) {
1297 remove_notification(info);
1298 inode->i_atime = inode->i_ctime = current_time(inode);
1299 }
1300 } else if (info->notify_owner != NULL) {
1301 ret = -EBUSY;
1302 } else {
1303 switch (notification->sigev_notify) {
1304 case SIGEV_NONE:
1305 info->notify.sigev_notify = SIGEV_NONE;
1306 break;
1307 case SIGEV_THREAD:
1308 info->notify_sock = sock;
1309 info->notify_cookie = nc;
1310 sock = NULL;
1311 nc = NULL;
1312 info->notify.sigev_notify = SIGEV_THREAD;
1313 break;
1314 case SIGEV_SIGNAL:
1315 info->notify.sigev_signo = notification->sigev_signo;
1316 info->notify.sigev_value = notification->sigev_value;
1317 info->notify.sigev_notify = SIGEV_SIGNAL;
1318 break;
1319 }
1320
1321 info->notify_owner = get_pid(task_tgid(current));
1322 info->notify_user_ns = get_user_ns(current_user_ns());
1323 inode->i_atime = inode->i_ctime = current_time(inode);
1324 }
1325 spin_unlock(&info->lock);
1326out_fput:
1327 fdput(f);
1328out:
1329 if (sock)
1330 netlink_detachskb(sock, nc);
1331 else
1332free_skb:
1333 dev_kfree_skb(nc);
1334
1335 return ret;
1336}
1337
1338SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1339 const struct sigevent __user *, u_notification)
1340{
1341 struct sigevent n, *p = NULL;
1342 if (u_notification) {
1343 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1344 return -EFAULT;
1345 p = &n;
1346 }
1347 return do_mq_notify(mqdes, p);
1348}
1349
1350static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1351{
1352 struct fd f;
1353 struct inode *inode;
1354 struct mqueue_inode_info *info;
1355
1356 if (new && (new->mq_flags & (~O_NONBLOCK)))
1357 return -EINVAL;
1358
1359 f = fdget(mqdes);
1360 if (!f.file)
1361 return -EBADF;
1362
1363 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1364 fdput(f);
1365 return -EBADF;
1366 }
1367
1368 inode = file_inode(f.file);
1369 info = MQUEUE_I(inode);
1370
1371 spin_lock(&info->lock);
1372
1373 if (old) {
1374 *old = info->attr;
1375 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1376 }
1377 if (new) {
1378 audit_mq_getsetattr(mqdes, new);
1379 spin_lock(&f.file->f_lock);
1380 if (new->mq_flags & O_NONBLOCK)
1381 f.file->f_flags |= O_NONBLOCK;
1382 else
1383 f.file->f_flags &= ~O_NONBLOCK;
1384 spin_unlock(&f.file->f_lock);
1385
1386 inode->i_atime = inode->i_ctime = current_time(inode);
1387 }
1388
1389 spin_unlock(&info->lock);
1390 fdput(f);
1391 return 0;
1392}
1393
1394SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1395 const struct mq_attr __user *, u_mqstat,
1396 struct mq_attr __user *, u_omqstat)
1397{
1398 int ret;
1399 struct mq_attr mqstat, omqstat;
1400 struct mq_attr *new = NULL, *old = NULL;
1401
1402 if (u_mqstat) {
1403 new = &mqstat;
1404 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1405 return -EFAULT;
1406 }
1407 if (u_omqstat)
1408 old = &omqstat;
1409
1410 ret = do_mq_getsetattr(mqdes, new, old);
1411 if (ret || !old)
1412 return ret;
1413
1414 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1415 return -EFAULT;
1416 return 0;
1417}
1418
1419#ifdef CONFIG_COMPAT
1420
1421struct compat_mq_attr {
1422 compat_long_t mq_flags; /* message queue flags */
1423 compat_long_t mq_maxmsg; /* maximum number of messages */
1424 compat_long_t mq_msgsize; /* maximum message size */
1425 compat_long_t mq_curmsgs; /* number of messages currently queued */
1426 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1427};
1428
1429static inline int get_compat_mq_attr(struct mq_attr *attr,
1430 const struct compat_mq_attr __user *uattr)
1431{
1432 struct compat_mq_attr v;
1433
1434 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1435 return -EFAULT;
1436
1437 memset(attr, 0, sizeof(*attr));
1438 attr->mq_flags = v.mq_flags;
1439 attr->mq_maxmsg = v.mq_maxmsg;
1440 attr->mq_msgsize = v.mq_msgsize;
1441 attr->mq_curmsgs = v.mq_curmsgs;
1442 return 0;
1443}
1444
1445static inline int put_compat_mq_attr(const struct mq_attr *attr,
1446 struct compat_mq_attr __user *uattr)
1447{
1448 struct compat_mq_attr v;
1449
1450 memset(&v, 0, sizeof(v));
1451 v.mq_flags = attr->mq_flags;
1452 v.mq_maxmsg = attr->mq_maxmsg;
1453 v.mq_msgsize = attr->mq_msgsize;
1454 v.mq_curmsgs = attr->mq_curmsgs;
1455 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1456 return -EFAULT;
1457 return 0;
1458}
1459
1460COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1461 int, oflag, compat_mode_t, mode,
1462 struct compat_mq_attr __user *, u_attr)
1463{
1464 struct mq_attr attr, *p = NULL;
1465 if (u_attr && oflag & O_CREAT) {
1466 p = &attr;
1467 if (get_compat_mq_attr(&attr, u_attr))
1468 return -EFAULT;
1469 }
1470 return do_mq_open(u_name, oflag, mode, p);
1471}
1472
1473COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1474 const struct compat_sigevent __user *, u_notification)
1475{
1476 struct sigevent n, *p = NULL;
1477 if (u_notification) {
1478 if (get_compat_sigevent(&n, u_notification))
1479 return -EFAULT;
1480 if (n.sigev_notify == SIGEV_THREAD)
1481 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1482 p = &n;
1483 }
1484 return do_mq_notify(mqdes, p);
1485}
1486
1487COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1488 const struct compat_mq_attr __user *, u_mqstat,
1489 struct compat_mq_attr __user *, u_omqstat)
1490{
1491 int ret;
1492 struct mq_attr mqstat, omqstat;
1493 struct mq_attr *new = NULL, *old = NULL;
1494
1495 if (u_mqstat) {
1496 new = &mqstat;
1497 if (get_compat_mq_attr(new, u_mqstat))
1498 return -EFAULT;
1499 }
1500 if (u_omqstat)
1501 old = &omqstat;
1502
1503 ret = do_mq_getsetattr(mqdes, new, old);
1504 if (ret || !old)
1505 return ret;
1506
1507 if (put_compat_mq_attr(old, u_omqstat))
1508 return -EFAULT;
1509 return 0;
1510}
1511#endif
1512
1513#ifdef CONFIG_COMPAT_32BIT_TIME
1514static int compat_prepare_timeout(const struct old_timespec32 __user *p,
1515 struct timespec64 *ts)
1516{
1517 if (get_old_timespec32(ts, p))
1518 return -EFAULT;
1519 if (!timespec64_valid(ts))
1520 return -EINVAL;
1521 return 0;
1522}
1523
1524SYSCALL_DEFINE5(mq_timedsend_time32, mqd_t, mqdes,
1525 const char __user *, u_msg_ptr,
1526 unsigned int, msg_len, unsigned int, msg_prio,
1527 const struct old_timespec32 __user *, u_abs_timeout)
1528{
1529 struct timespec64 ts, *p = NULL;
1530 if (u_abs_timeout) {
1531 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1532 if (res)
1533 return res;
1534 p = &ts;
1535 }
1536 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1537}
1538
1539SYSCALL_DEFINE5(mq_timedreceive_time32, mqd_t, mqdes,
1540 char __user *, u_msg_ptr,
1541 unsigned int, msg_len, unsigned int __user *, u_msg_prio,
1542 const struct old_timespec32 __user *, u_abs_timeout)
1543{
1544 struct timespec64 ts, *p = NULL;
1545 if (u_abs_timeout) {
1546 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1547 if (res)
1548 return res;
1549 p = &ts;
1550 }
1551 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1552}
1553#endif
1554
1555static const struct inode_operations mqueue_dir_inode_operations = {
1556 .lookup = simple_lookup,
1557 .create = mqueue_create,
1558 .unlink = mqueue_unlink,
1559};
1560
1561static const struct file_operations mqueue_file_operations = {
1562 .flush = mqueue_flush_file,
1563 .poll = mqueue_poll_file,
1564 .read = mqueue_read_file,
1565 .llseek = default_llseek,
1566};
1567
1568static const struct super_operations mqueue_super_ops = {
1569 .alloc_inode = mqueue_alloc_inode,
1570 .free_inode = mqueue_free_inode,
1571 .evict_inode = mqueue_evict_inode,
1572 .statfs = simple_statfs,
1573};
1574
1575static const struct fs_context_operations mqueue_fs_context_ops = {
1576 .free = mqueue_fs_context_free,
1577 .get_tree = mqueue_get_tree,
1578};
1579
1580static struct file_system_type mqueue_fs_type = {
1581 .name = "mqueue",
1582 .init_fs_context = mqueue_init_fs_context,
1583 .kill_sb = kill_litter_super,
1584 .fs_flags = FS_USERNS_MOUNT,
1585};
1586
1587int mq_init_ns(struct ipc_namespace *ns)
1588{
1589 struct vfsmount *m;
1590
1591 ns->mq_queues_count = 0;
1592 ns->mq_queues_max = DFLT_QUEUESMAX;
1593 ns->mq_msg_max = DFLT_MSGMAX;
1594 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1595 ns->mq_msg_default = DFLT_MSG;
1596 ns->mq_msgsize_default = DFLT_MSGSIZE;
1597
1598 m = mq_create_mount(ns);
1599 if (IS_ERR(m))
1600 return PTR_ERR(m);
1601 ns->mq_mnt = m;
1602 return 0;
1603}
1604
1605void mq_clear_sbinfo(struct ipc_namespace *ns)
1606{
1607 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1608}
1609
1610void mq_put_mnt(struct ipc_namespace *ns)
1611{
1612 kern_unmount(ns->mq_mnt);
1613}
1614
1615static int __init init_mqueue_fs(void)
1616{
1617 int error;
1618
1619 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1620 sizeof(struct mqueue_inode_info), 0,
1621 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1622 if (mqueue_inode_cachep == NULL)
1623 return -ENOMEM;
1624
1625 /* ignore failures - they are not fatal */
1626 mq_sysctl_table = mq_register_sysctl_table();
1627
1628 error = register_filesystem(&mqueue_fs_type);
1629 if (error)
1630 goto out_sysctl;
1631
1632 spin_lock_init(&mq_lock);
1633
1634 error = mq_init_ns(&init_ipc_ns);
1635 if (error)
1636 goto out_filesystem;
1637
1638 return 0;
1639
1640out_filesystem:
1641 unregister_filesystem(&mqueue_fs_type);
1642out_sysctl:
1643 if (mq_sysctl_table)
1644 unregister_sysctl_table(mq_sysctl_table);
1645 kmem_cache_destroy(mqueue_inode_cachep);
1646 return error;
1647}
1648
1649device_initcall(init_mqueue_fs);