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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/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);