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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/netlink.h>
28#include <linux/syscalls.h>
29#include <linux/audit.h>
30#include <linux/signal.h>
31#include <linux/mutex.h>
32#include <linux/nsproxy.h>
33#include <linux/pid.h>
34#include <linux/ipc_namespace.h>
35#include <linux/slab.h>
36
37#include <net/sock.h>
38#include "util.h"
39
40#define MQUEUE_MAGIC 0x19800202
41#define DIRENT_SIZE 20
42#define FILENT_SIZE 80
43
44#define SEND 0
45#define RECV 1
46
47#define STATE_NONE 0
48#define STATE_PENDING 1
49#define STATE_READY 2
50
51struct ext_wait_queue { /* queue of sleeping tasks */
52 struct task_struct *task;
53 struct list_head list;
54 struct msg_msg *msg; /* ptr of loaded message */
55 int state; /* one of STATE_* values */
56};
57
58struct mqueue_inode_info {
59 spinlock_t lock;
60 struct inode vfs_inode;
61 wait_queue_head_t wait_q;
62
63 struct msg_msg **messages;
64 struct mq_attr attr;
65
66 struct sigevent notify;
67 struct pid* notify_owner;
68 struct user_struct *user; /* user who created, for accounting */
69 struct sock *notify_sock;
70 struct sk_buff *notify_cookie;
71
72 /* for tasks waiting for free space and messages, respectively */
73 struct ext_wait_queue e_wait_q[2];
74
75 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
76};
77
78static const struct inode_operations mqueue_dir_inode_operations;
79static const struct file_operations mqueue_file_operations;
80static const struct super_operations mqueue_super_ops;
81static void remove_notification(struct mqueue_inode_info *info);
82
83static struct kmem_cache *mqueue_inode_cachep;
84
85static struct ctl_table_header * mq_sysctl_table;
86
87static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
88{
89 return container_of(inode, struct mqueue_inode_info, vfs_inode);
90}
91
92/*
93 * This routine should be called with the mq_lock held.
94 */
95static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
96{
97 return get_ipc_ns(inode->i_sb->s_fs_info);
98}
99
100static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
101{
102 struct ipc_namespace *ns;
103
104 spin_lock(&mq_lock);
105 ns = __get_ns_from_inode(inode);
106 spin_unlock(&mq_lock);
107 return ns;
108}
109
110static struct inode *mqueue_get_inode(struct super_block *sb,
111 struct ipc_namespace *ipc_ns, int mode,
112 struct mq_attr *attr)
113{
114 struct user_struct *u = current_user();
115 struct inode *inode;
116 int ret = -ENOMEM;
117
118 inode = new_inode(sb);
119 if (!inode)
120 goto err;
121
122 inode->i_ino = get_next_ino();
123 inode->i_mode = mode;
124 inode->i_uid = current_fsuid();
125 inode->i_gid = current_fsgid();
126 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
127
128 if (S_ISREG(mode)) {
129 struct mqueue_inode_info *info;
130 struct task_struct *p = current;
131 unsigned long mq_bytes, mq_msg_tblsz;
132
133 inode->i_fop = &mqueue_file_operations;
134 inode->i_size = FILENT_SIZE;
135 /* mqueue specific info */
136 info = MQUEUE_I(inode);
137 spin_lock_init(&info->lock);
138 init_waitqueue_head(&info->wait_q);
139 INIT_LIST_HEAD(&info->e_wait_q[0].list);
140 INIT_LIST_HEAD(&info->e_wait_q[1].list);
141 info->notify_owner = NULL;
142 info->qsize = 0;
143 info->user = NULL; /* set when all is ok */
144 memset(&info->attr, 0, sizeof(info->attr));
145 info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
146 info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
147 if (attr) {
148 info->attr.mq_maxmsg = attr->mq_maxmsg;
149 info->attr.mq_msgsize = attr->mq_msgsize;
150 }
151 mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
152 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
153 if (!info->messages)
154 goto out_inode;
155
156 mq_bytes = (mq_msg_tblsz +
157 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
158
159 spin_lock(&mq_lock);
160 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
161 u->mq_bytes + mq_bytes > task_rlimit(p, RLIMIT_MSGQUEUE)) {
162 spin_unlock(&mq_lock);
163 /* mqueue_evict_inode() releases info->messages */
164 ret = -EMFILE;
165 goto out_inode;
166 }
167 u->mq_bytes += mq_bytes;
168 spin_unlock(&mq_lock);
169
170 /* all is ok */
171 info->user = get_uid(u);
172 } else if (S_ISDIR(mode)) {
173 inc_nlink(inode);
174 /* Some things misbehave if size == 0 on a directory */
175 inode->i_size = 2 * DIRENT_SIZE;
176 inode->i_op = &mqueue_dir_inode_operations;
177 inode->i_fop = &simple_dir_operations;
178 }
179
180 return inode;
181out_inode:
182 iput(inode);
183err:
184 return ERR_PTR(ret);
185}
186
187static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
188{
189 struct inode *inode;
190 struct ipc_namespace *ns = data;
191 int error;
192
193 sb->s_blocksize = PAGE_CACHE_SIZE;
194 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
195 sb->s_magic = MQUEUE_MAGIC;
196 sb->s_op = &mqueue_super_ops;
197
198 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO,
199 NULL);
200 if (IS_ERR(inode)) {
201 error = PTR_ERR(inode);
202 goto out;
203 }
204
205 sb->s_root = d_alloc_root(inode);
206 if (!sb->s_root) {
207 iput(inode);
208 error = -ENOMEM;
209 goto out;
210 }
211 error = 0;
212
213out:
214 return error;
215}
216
217static struct dentry *mqueue_mount(struct file_system_type *fs_type,
218 int flags, const char *dev_name,
219 void *data)
220{
221 if (!(flags & MS_KERNMOUNT))
222 data = current->nsproxy->ipc_ns;
223 return mount_ns(fs_type, flags, data, mqueue_fill_super);
224}
225
226static void init_once(void *foo)
227{
228 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
229
230 inode_init_once(&p->vfs_inode);
231}
232
233static struct inode *mqueue_alloc_inode(struct super_block *sb)
234{
235 struct mqueue_inode_info *ei;
236
237 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
238 if (!ei)
239 return NULL;
240 return &ei->vfs_inode;
241}
242
243static void mqueue_i_callback(struct rcu_head *head)
244{
245 struct inode *inode = container_of(head, struct inode, i_rcu);
246 INIT_LIST_HEAD(&inode->i_dentry);
247 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
248}
249
250static void mqueue_destroy_inode(struct inode *inode)
251{
252 call_rcu(&inode->i_rcu, mqueue_i_callback);
253}
254
255static void mqueue_evict_inode(struct inode *inode)
256{
257 struct mqueue_inode_info *info;
258 struct user_struct *user;
259 unsigned long mq_bytes;
260 int i;
261 struct ipc_namespace *ipc_ns;
262
263 end_writeback(inode);
264
265 if (S_ISDIR(inode->i_mode))
266 return;
267
268 ipc_ns = get_ns_from_inode(inode);
269 info = MQUEUE_I(inode);
270 spin_lock(&info->lock);
271 for (i = 0; i < info->attr.mq_curmsgs; i++)
272 free_msg(info->messages[i]);
273 kfree(info->messages);
274 spin_unlock(&info->lock);
275
276 /* Total amount of bytes accounted for the mqueue */
277 mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *)
278 + info->attr.mq_msgsize);
279 user = info->user;
280 if (user) {
281 spin_lock(&mq_lock);
282 user->mq_bytes -= mq_bytes;
283 /*
284 * get_ns_from_inode() ensures that the
285 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
286 * to which we now hold a reference, or it is NULL.
287 * We can't put it here under mq_lock, though.
288 */
289 if (ipc_ns)
290 ipc_ns->mq_queues_count--;
291 spin_unlock(&mq_lock);
292 free_uid(user);
293 }
294 if (ipc_ns)
295 put_ipc_ns(ipc_ns);
296}
297
298static int mqueue_create(struct inode *dir, struct dentry *dentry,
299 int mode, struct nameidata *nd)
300{
301 struct inode *inode;
302 struct mq_attr *attr = dentry->d_fsdata;
303 int error;
304 struct ipc_namespace *ipc_ns;
305
306 spin_lock(&mq_lock);
307 ipc_ns = __get_ns_from_inode(dir);
308 if (!ipc_ns) {
309 error = -EACCES;
310 goto out_unlock;
311 }
312 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
313 !capable(CAP_SYS_RESOURCE)) {
314 error = -ENOSPC;
315 goto out_unlock;
316 }
317 ipc_ns->mq_queues_count++;
318 spin_unlock(&mq_lock);
319
320 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
321 if (IS_ERR(inode)) {
322 error = PTR_ERR(inode);
323 spin_lock(&mq_lock);
324 ipc_ns->mq_queues_count--;
325 goto out_unlock;
326 }
327
328 put_ipc_ns(ipc_ns);
329 dir->i_size += DIRENT_SIZE;
330 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
331
332 d_instantiate(dentry, inode);
333 dget(dentry);
334 return 0;
335out_unlock:
336 spin_unlock(&mq_lock);
337 if (ipc_ns)
338 put_ipc_ns(ipc_ns);
339 return error;
340}
341
342static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
343{
344 struct inode *inode = dentry->d_inode;
345
346 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
347 dir->i_size -= DIRENT_SIZE;
348 drop_nlink(inode);
349 dput(dentry);
350 return 0;
351}
352
353/*
354* This is routine for system read from queue file.
355* To avoid mess with doing here some sort of mq_receive we allow
356* to read only queue size & notification info (the only values
357* that are interesting from user point of view and aren't accessible
358* through std routines)
359*/
360static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
361 size_t count, loff_t *off)
362{
363 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
364 char buffer[FILENT_SIZE];
365 ssize_t ret;
366
367 spin_lock(&info->lock);
368 snprintf(buffer, sizeof(buffer),
369 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
370 info->qsize,
371 info->notify_owner ? info->notify.sigev_notify : 0,
372 (info->notify_owner &&
373 info->notify.sigev_notify == SIGEV_SIGNAL) ?
374 info->notify.sigev_signo : 0,
375 pid_vnr(info->notify_owner));
376 spin_unlock(&info->lock);
377 buffer[sizeof(buffer)-1] = '\0';
378
379 ret = simple_read_from_buffer(u_data, count, off, buffer,
380 strlen(buffer));
381 if (ret <= 0)
382 return ret;
383
384 filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
385 return ret;
386}
387
388static int mqueue_flush_file(struct file *filp, fl_owner_t id)
389{
390 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
391
392 spin_lock(&info->lock);
393 if (task_tgid(current) == info->notify_owner)
394 remove_notification(info);
395
396 spin_unlock(&info->lock);
397 return 0;
398}
399
400static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
401{
402 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
403 int retval = 0;
404
405 poll_wait(filp, &info->wait_q, poll_tab);
406
407 spin_lock(&info->lock);
408 if (info->attr.mq_curmsgs)
409 retval = POLLIN | POLLRDNORM;
410
411 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
412 retval |= POLLOUT | POLLWRNORM;
413 spin_unlock(&info->lock);
414
415 return retval;
416}
417
418/* Adds current to info->e_wait_q[sr] before element with smaller prio */
419static void wq_add(struct mqueue_inode_info *info, int sr,
420 struct ext_wait_queue *ewp)
421{
422 struct ext_wait_queue *walk;
423
424 ewp->task = current;
425
426 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
427 if (walk->task->static_prio <= current->static_prio) {
428 list_add_tail(&ewp->list, &walk->list);
429 return;
430 }
431 }
432 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
433}
434
435/*
436 * Puts current task to sleep. Caller must hold queue lock. After return
437 * lock isn't held.
438 * sr: SEND or RECV
439 */
440static int wq_sleep(struct mqueue_inode_info *info, int sr,
441 ktime_t *timeout, struct ext_wait_queue *ewp)
442{
443 int retval;
444 signed long time;
445
446 wq_add(info, sr, ewp);
447
448 for (;;) {
449 set_current_state(TASK_INTERRUPTIBLE);
450
451 spin_unlock(&info->lock);
452 time = schedule_hrtimeout_range_clock(timeout,
453 HRTIMER_MODE_ABS, 0, CLOCK_REALTIME);
454
455 while (ewp->state == STATE_PENDING)
456 cpu_relax();
457
458 if (ewp->state == STATE_READY) {
459 retval = 0;
460 goto out;
461 }
462 spin_lock(&info->lock);
463 if (ewp->state == STATE_READY) {
464 retval = 0;
465 goto out_unlock;
466 }
467 if (signal_pending(current)) {
468 retval = -ERESTARTSYS;
469 break;
470 }
471 if (time == 0) {
472 retval = -ETIMEDOUT;
473 break;
474 }
475 }
476 list_del(&ewp->list);
477out_unlock:
478 spin_unlock(&info->lock);
479out:
480 return retval;
481}
482
483/*
484 * Returns waiting task that should be serviced first or NULL if none exists
485 */
486static struct ext_wait_queue *wq_get_first_waiter(
487 struct mqueue_inode_info *info, int sr)
488{
489 struct list_head *ptr;
490
491 ptr = info->e_wait_q[sr].list.prev;
492 if (ptr == &info->e_wait_q[sr].list)
493 return NULL;
494 return list_entry(ptr, struct ext_wait_queue, list);
495}
496
497/* Auxiliary functions to manipulate messages' list */
498static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
499{
500 int k;
501
502 k = info->attr.mq_curmsgs - 1;
503 while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
504 info->messages[k + 1] = info->messages[k];
505 k--;
506 }
507 info->attr.mq_curmsgs++;
508 info->qsize += ptr->m_ts;
509 info->messages[k + 1] = ptr;
510}
511
512static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
513{
514 info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
515 return info->messages[info->attr.mq_curmsgs];
516}
517
518static inline void set_cookie(struct sk_buff *skb, char code)
519{
520 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
521}
522
523/*
524 * The next function is only to split too long sys_mq_timedsend
525 */
526static void __do_notify(struct mqueue_inode_info *info)
527{
528 /* notification
529 * invoked when there is registered process and there isn't process
530 * waiting synchronously for message AND state of queue changed from
531 * empty to not empty. Here we are sure that no one is waiting
532 * synchronously. */
533 if (info->notify_owner &&
534 info->attr.mq_curmsgs == 1) {
535 struct siginfo sig_i;
536 switch (info->notify.sigev_notify) {
537 case SIGEV_NONE:
538 break;
539 case SIGEV_SIGNAL:
540 /* sends signal */
541
542 sig_i.si_signo = info->notify.sigev_signo;
543 sig_i.si_errno = 0;
544 sig_i.si_code = SI_MESGQ;
545 sig_i.si_value = info->notify.sigev_value;
546 sig_i.si_pid = task_tgid_nr_ns(current,
547 ns_of_pid(info->notify_owner));
548 sig_i.si_uid = current_uid();
549
550 kill_pid_info(info->notify.sigev_signo,
551 &sig_i, info->notify_owner);
552 break;
553 case SIGEV_THREAD:
554 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
555 netlink_sendskb(info->notify_sock, info->notify_cookie);
556 break;
557 }
558 /* after notification unregisters process */
559 put_pid(info->notify_owner);
560 info->notify_owner = NULL;
561 }
562 wake_up(&info->wait_q);
563}
564
565static int prepare_timeout(const struct timespec __user *u_abs_timeout,
566 ktime_t *expires, struct timespec *ts)
567{
568 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
569 return -EFAULT;
570 if (!timespec_valid(ts))
571 return -EINVAL;
572
573 *expires = timespec_to_ktime(*ts);
574 return 0;
575}
576
577static void remove_notification(struct mqueue_inode_info *info)
578{
579 if (info->notify_owner != NULL &&
580 info->notify.sigev_notify == SIGEV_THREAD) {
581 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
582 netlink_sendskb(info->notify_sock, info->notify_cookie);
583 }
584 put_pid(info->notify_owner);
585 info->notify_owner = NULL;
586}
587
588static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
589{
590 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
591 return 0;
592 if (capable(CAP_SYS_RESOURCE)) {
593 if (attr->mq_maxmsg > HARD_MSGMAX)
594 return 0;
595 } else {
596 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
597 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
598 return 0;
599 }
600 /* check for overflow */
601 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
602 return 0;
603 if ((unsigned long)(attr->mq_maxmsg * (attr->mq_msgsize
604 + sizeof (struct msg_msg *))) <
605 (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
606 return 0;
607 return 1;
608}
609
610/*
611 * Invoked when creating a new queue via sys_mq_open
612 */
613static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
614 struct dentry *dentry, int oflag, mode_t mode,
615 struct mq_attr *attr)
616{
617 const struct cred *cred = current_cred();
618 struct file *result;
619 int ret;
620
621 if (attr) {
622 if (!mq_attr_ok(ipc_ns, attr)) {
623 ret = -EINVAL;
624 goto out;
625 }
626 /* store for use during create */
627 dentry->d_fsdata = attr;
628 }
629
630 mode &= ~current_umask();
631 ret = mnt_want_write(ipc_ns->mq_mnt);
632 if (ret)
633 goto out;
634 ret = vfs_create(dir->d_inode, dentry, mode, NULL);
635 dentry->d_fsdata = NULL;
636 if (ret)
637 goto out_drop_write;
638
639 result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
640 /*
641 * dentry_open() took a persistent mnt_want_write(),
642 * so we can now drop this one.
643 */
644 mnt_drop_write(ipc_ns->mq_mnt);
645 return result;
646
647out_drop_write:
648 mnt_drop_write(ipc_ns->mq_mnt);
649out:
650 dput(dentry);
651 mntput(ipc_ns->mq_mnt);
652 return ERR_PTR(ret);
653}
654
655/* Opens existing queue */
656static struct file *do_open(struct ipc_namespace *ipc_ns,
657 struct dentry *dentry, int oflag)
658{
659 int ret;
660 const struct cred *cred = current_cred();
661
662 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
663 MAY_READ | MAY_WRITE };
664
665 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
666 ret = -EINVAL;
667 goto err;
668 }
669
670 if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
671 ret = -EACCES;
672 goto err;
673 }
674
675 return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
676
677err:
678 dput(dentry);
679 mntput(ipc_ns->mq_mnt);
680 return ERR_PTR(ret);
681}
682
683SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
684 struct mq_attr __user *, u_attr)
685{
686 struct dentry *dentry;
687 struct file *filp;
688 char *name;
689 struct mq_attr attr;
690 int fd, error;
691 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
692
693 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
694 return -EFAULT;
695
696 audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
697
698 if (IS_ERR(name = getname(u_name)))
699 return PTR_ERR(name);
700
701 fd = get_unused_fd_flags(O_CLOEXEC);
702 if (fd < 0)
703 goto out_putname;
704
705 mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
706 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
707 if (IS_ERR(dentry)) {
708 error = PTR_ERR(dentry);
709 goto out_putfd;
710 }
711 mntget(ipc_ns->mq_mnt);
712
713 if (oflag & O_CREAT) {
714 if (dentry->d_inode) { /* entry already exists */
715 audit_inode(name, dentry);
716 if (oflag & O_EXCL) {
717 error = -EEXIST;
718 goto out;
719 }
720 filp = do_open(ipc_ns, dentry, oflag);
721 } else {
722 filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
723 dentry, oflag, mode,
724 u_attr ? &attr : NULL);
725 }
726 } else {
727 if (!dentry->d_inode) {
728 error = -ENOENT;
729 goto out;
730 }
731 audit_inode(name, dentry);
732 filp = do_open(ipc_ns, dentry, oflag);
733 }
734
735 if (IS_ERR(filp)) {
736 error = PTR_ERR(filp);
737 goto out_putfd;
738 }
739
740 fd_install(fd, filp);
741 goto out_upsem;
742
743out:
744 dput(dentry);
745 mntput(ipc_ns->mq_mnt);
746out_putfd:
747 put_unused_fd(fd);
748 fd = error;
749out_upsem:
750 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
751out_putname:
752 putname(name);
753 return fd;
754}
755
756SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
757{
758 int err;
759 char *name;
760 struct dentry *dentry;
761 struct inode *inode = NULL;
762 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
763
764 name = getname(u_name);
765 if (IS_ERR(name))
766 return PTR_ERR(name);
767
768 mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
769 I_MUTEX_PARENT);
770 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
771 if (IS_ERR(dentry)) {
772 err = PTR_ERR(dentry);
773 goto out_unlock;
774 }
775
776 if (!dentry->d_inode) {
777 err = -ENOENT;
778 goto out_err;
779 }
780
781 inode = dentry->d_inode;
782 if (inode)
783 ihold(inode);
784 err = mnt_want_write(ipc_ns->mq_mnt);
785 if (err)
786 goto out_err;
787 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
788 mnt_drop_write(ipc_ns->mq_mnt);
789out_err:
790 dput(dentry);
791
792out_unlock:
793 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
794 putname(name);
795 if (inode)
796 iput(inode);
797
798 return err;
799}
800
801/* Pipelined send and receive functions.
802 *
803 * If a receiver finds no waiting message, then it registers itself in the
804 * list of waiting receivers. A sender checks that list before adding the new
805 * message into the message array. If there is a waiting receiver, then it
806 * bypasses the message array and directly hands the message over to the
807 * receiver.
808 * The receiver accepts the message and returns without grabbing the queue
809 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
810 * are necessary. The same algorithm is used for sysv semaphores, see
811 * ipc/sem.c for more details.
812 *
813 * The same algorithm is used for senders.
814 */
815
816/* pipelined_send() - send a message directly to the task waiting in
817 * sys_mq_timedreceive() (without inserting message into a queue).
818 */
819static inline void pipelined_send(struct mqueue_inode_info *info,
820 struct msg_msg *message,
821 struct ext_wait_queue *receiver)
822{
823 receiver->msg = message;
824 list_del(&receiver->list);
825 receiver->state = STATE_PENDING;
826 wake_up_process(receiver->task);
827 smp_wmb();
828 receiver->state = STATE_READY;
829}
830
831/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
832 * gets its message and put to the queue (we have one free place for sure). */
833static inline void pipelined_receive(struct mqueue_inode_info *info)
834{
835 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
836
837 if (!sender) {
838 /* for poll */
839 wake_up_interruptible(&info->wait_q);
840 return;
841 }
842 msg_insert(sender->msg, info);
843 list_del(&sender->list);
844 sender->state = STATE_PENDING;
845 wake_up_process(sender->task);
846 smp_wmb();
847 sender->state = STATE_READY;
848}
849
850SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
851 size_t, msg_len, unsigned int, msg_prio,
852 const struct timespec __user *, u_abs_timeout)
853{
854 struct file *filp;
855 struct inode *inode;
856 struct ext_wait_queue wait;
857 struct ext_wait_queue *receiver;
858 struct msg_msg *msg_ptr;
859 struct mqueue_inode_info *info;
860 ktime_t expires, *timeout = NULL;
861 struct timespec ts;
862 int ret;
863
864 if (u_abs_timeout) {
865 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
866 if (res)
867 return res;
868 timeout = &expires;
869 }
870
871 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
872 return -EINVAL;
873
874 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
875
876 filp = fget(mqdes);
877 if (unlikely(!filp)) {
878 ret = -EBADF;
879 goto out;
880 }
881
882 inode = filp->f_path.dentry->d_inode;
883 if (unlikely(filp->f_op != &mqueue_file_operations)) {
884 ret = -EBADF;
885 goto out_fput;
886 }
887 info = MQUEUE_I(inode);
888 audit_inode(NULL, filp->f_path.dentry);
889
890 if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
891 ret = -EBADF;
892 goto out_fput;
893 }
894
895 if (unlikely(msg_len > info->attr.mq_msgsize)) {
896 ret = -EMSGSIZE;
897 goto out_fput;
898 }
899
900 /* First try to allocate memory, before doing anything with
901 * existing queues. */
902 msg_ptr = load_msg(u_msg_ptr, msg_len);
903 if (IS_ERR(msg_ptr)) {
904 ret = PTR_ERR(msg_ptr);
905 goto out_fput;
906 }
907 msg_ptr->m_ts = msg_len;
908 msg_ptr->m_type = msg_prio;
909
910 spin_lock(&info->lock);
911
912 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
913 if (filp->f_flags & O_NONBLOCK) {
914 spin_unlock(&info->lock);
915 ret = -EAGAIN;
916 } else {
917 wait.task = current;
918 wait.msg = (void *) msg_ptr;
919 wait.state = STATE_NONE;
920 ret = wq_sleep(info, SEND, timeout, &wait);
921 }
922 if (ret < 0)
923 free_msg(msg_ptr);
924 } else {
925 receiver = wq_get_first_waiter(info, RECV);
926 if (receiver) {
927 pipelined_send(info, msg_ptr, receiver);
928 } else {
929 /* adds message to the queue */
930 msg_insert(msg_ptr, info);
931 __do_notify(info);
932 }
933 inode->i_atime = inode->i_mtime = inode->i_ctime =
934 CURRENT_TIME;
935 spin_unlock(&info->lock);
936 ret = 0;
937 }
938out_fput:
939 fput(filp);
940out:
941 return ret;
942}
943
944SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
945 size_t, msg_len, unsigned int __user *, u_msg_prio,
946 const struct timespec __user *, u_abs_timeout)
947{
948 ssize_t ret;
949 struct msg_msg *msg_ptr;
950 struct file *filp;
951 struct inode *inode;
952 struct mqueue_inode_info *info;
953 struct ext_wait_queue wait;
954 ktime_t expires, *timeout = NULL;
955 struct timespec ts;
956
957 if (u_abs_timeout) {
958 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
959 if (res)
960 return res;
961 timeout = &expires;
962 }
963
964 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
965
966 filp = fget(mqdes);
967 if (unlikely(!filp)) {
968 ret = -EBADF;
969 goto out;
970 }
971
972 inode = filp->f_path.dentry->d_inode;
973 if (unlikely(filp->f_op != &mqueue_file_operations)) {
974 ret = -EBADF;
975 goto out_fput;
976 }
977 info = MQUEUE_I(inode);
978 audit_inode(NULL, filp->f_path.dentry);
979
980 if (unlikely(!(filp->f_mode & FMODE_READ))) {
981 ret = -EBADF;
982 goto out_fput;
983 }
984
985 /* checks if buffer is big enough */
986 if (unlikely(msg_len < info->attr.mq_msgsize)) {
987 ret = -EMSGSIZE;
988 goto out_fput;
989 }
990
991 spin_lock(&info->lock);
992 if (info->attr.mq_curmsgs == 0) {
993 if (filp->f_flags & O_NONBLOCK) {
994 spin_unlock(&info->lock);
995 ret = -EAGAIN;
996 } else {
997 wait.task = current;
998 wait.state = STATE_NONE;
999 ret = wq_sleep(info, RECV, timeout, &wait);
1000 msg_ptr = wait.msg;
1001 }
1002 } else {
1003 msg_ptr = msg_get(info);
1004
1005 inode->i_atime = inode->i_mtime = inode->i_ctime =
1006 CURRENT_TIME;
1007
1008 /* There is now free space in queue. */
1009 pipelined_receive(info);
1010 spin_unlock(&info->lock);
1011 ret = 0;
1012 }
1013 if (ret == 0) {
1014 ret = msg_ptr->m_ts;
1015
1016 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1017 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1018 ret = -EFAULT;
1019 }
1020 free_msg(msg_ptr);
1021 }
1022out_fput:
1023 fput(filp);
1024out:
1025 return ret;
1026}
1027
1028/*
1029 * Notes: the case when user wants us to deregister (with NULL as pointer)
1030 * and he isn't currently owner of notification, will be silently discarded.
1031 * It isn't explicitly defined in the POSIX.
1032 */
1033SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1034 const struct sigevent __user *, u_notification)
1035{
1036 int ret;
1037 struct file *filp;
1038 struct sock *sock;
1039 struct inode *inode;
1040 struct sigevent notification;
1041 struct mqueue_inode_info *info;
1042 struct sk_buff *nc;
1043
1044 if (u_notification) {
1045 if (copy_from_user(¬ification, u_notification,
1046 sizeof(struct sigevent)))
1047 return -EFAULT;
1048 }
1049
1050 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL);
1051
1052 nc = NULL;
1053 sock = NULL;
1054 if (u_notification != NULL) {
1055 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1056 notification.sigev_notify != SIGEV_SIGNAL &&
1057 notification.sigev_notify != SIGEV_THREAD))
1058 return -EINVAL;
1059 if (notification.sigev_notify == SIGEV_SIGNAL &&
1060 !valid_signal(notification.sigev_signo)) {
1061 return -EINVAL;
1062 }
1063 if (notification.sigev_notify == SIGEV_THREAD) {
1064 long timeo;
1065
1066 /* create the notify skb */
1067 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1068 if (!nc) {
1069 ret = -ENOMEM;
1070 goto out;
1071 }
1072 if (copy_from_user(nc->data,
1073 notification.sigev_value.sival_ptr,
1074 NOTIFY_COOKIE_LEN)) {
1075 ret = -EFAULT;
1076 goto out;
1077 }
1078
1079 /* TODO: add a header? */
1080 skb_put(nc, NOTIFY_COOKIE_LEN);
1081 /* and attach it to the socket */
1082retry:
1083 filp = fget(notification.sigev_signo);
1084 if (!filp) {
1085 ret = -EBADF;
1086 goto out;
1087 }
1088 sock = netlink_getsockbyfilp(filp);
1089 fput(filp);
1090 if (IS_ERR(sock)) {
1091 ret = PTR_ERR(sock);
1092 sock = NULL;
1093 goto out;
1094 }
1095
1096 timeo = MAX_SCHEDULE_TIMEOUT;
1097 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1098 if (ret == 1)
1099 goto retry;
1100 if (ret) {
1101 sock = NULL;
1102 nc = NULL;
1103 goto out;
1104 }
1105 }
1106 }
1107
1108 filp = fget(mqdes);
1109 if (!filp) {
1110 ret = -EBADF;
1111 goto out;
1112 }
1113
1114 inode = filp->f_path.dentry->d_inode;
1115 if (unlikely(filp->f_op != &mqueue_file_operations)) {
1116 ret = -EBADF;
1117 goto out_fput;
1118 }
1119 info = MQUEUE_I(inode);
1120
1121 ret = 0;
1122 spin_lock(&info->lock);
1123 if (u_notification == NULL) {
1124 if (info->notify_owner == task_tgid(current)) {
1125 remove_notification(info);
1126 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1127 }
1128 } else if (info->notify_owner != NULL) {
1129 ret = -EBUSY;
1130 } else {
1131 switch (notification.sigev_notify) {
1132 case SIGEV_NONE:
1133 info->notify.sigev_notify = SIGEV_NONE;
1134 break;
1135 case SIGEV_THREAD:
1136 info->notify_sock = sock;
1137 info->notify_cookie = nc;
1138 sock = NULL;
1139 nc = NULL;
1140 info->notify.sigev_notify = SIGEV_THREAD;
1141 break;
1142 case SIGEV_SIGNAL:
1143 info->notify.sigev_signo = notification.sigev_signo;
1144 info->notify.sigev_value = notification.sigev_value;
1145 info->notify.sigev_notify = SIGEV_SIGNAL;
1146 break;
1147 }
1148
1149 info->notify_owner = get_pid(task_tgid(current));
1150 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1151 }
1152 spin_unlock(&info->lock);
1153out_fput:
1154 fput(filp);
1155out:
1156 if (sock) {
1157 netlink_detachskb(sock, nc);
1158 } else if (nc) {
1159 dev_kfree_skb(nc);
1160 }
1161 return ret;
1162}
1163
1164SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1165 const struct mq_attr __user *, u_mqstat,
1166 struct mq_attr __user *, u_omqstat)
1167{
1168 int ret;
1169 struct mq_attr mqstat, omqstat;
1170 struct file *filp;
1171 struct inode *inode;
1172 struct mqueue_inode_info *info;
1173
1174 if (u_mqstat != NULL) {
1175 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1176 return -EFAULT;
1177 if (mqstat.mq_flags & (~O_NONBLOCK))
1178 return -EINVAL;
1179 }
1180
1181 filp = fget(mqdes);
1182 if (!filp) {
1183 ret = -EBADF;
1184 goto out;
1185 }
1186
1187 inode = filp->f_path.dentry->d_inode;
1188 if (unlikely(filp->f_op != &mqueue_file_operations)) {
1189 ret = -EBADF;
1190 goto out_fput;
1191 }
1192 info = MQUEUE_I(inode);
1193
1194 spin_lock(&info->lock);
1195
1196 omqstat = info->attr;
1197 omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1198 if (u_mqstat) {
1199 audit_mq_getsetattr(mqdes, &mqstat);
1200 spin_lock(&filp->f_lock);
1201 if (mqstat.mq_flags & O_NONBLOCK)
1202 filp->f_flags |= O_NONBLOCK;
1203 else
1204 filp->f_flags &= ~O_NONBLOCK;
1205 spin_unlock(&filp->f_lock);
1206
1207 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1208 }
1209
1210 spin_unlock(&info->lock);
1211
1212 ret = 0;
1213 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1214 sizeof(struct mq_attr)))
1215 ret = -EFAULT;
1216
1217out_fput:
1218 fput(filp);
1219out:
1220 return ret;
1221}
1222
1223static const struct inode_operations mqueue_dir_inode_operations = {
1224 .lookup = simple_lookup,
1225 .create = mqueue_create,
1226 .unlink = mqueue_unlink,
1227};
1228
1229static const struct file_operations mqueue_file_operations = {
1230 .flush = mqueue_flush_file,
1231 .poll = mqueue_poll_file,
1232 .read = mqueue_read_file,
1233 .llseek = default_llseek,
1234};
1235
1236static const struct super_operations mqueue_super_ops = {
1237 .alloc_inode = mqueue_alloc_inode,
1238 .destroy_inode = mqueue_destroy_inode,
1239 .evict_inode = mqueue_evict_inode,
1240 .statfs = simple_statfs,
1241};
1242
1243static struct file_system_type mqueue_fs_type = {
1244 .name = "mqueue",
1245 .mount = mqueue_mount,
1246 .kill_sb = kill_litter_super,
1247};
1248
1249int mq_init_ns(struct ipc_namespace *ns)
1250{
1251 ns->mq_queues_count = 0;
1252 ns->mq_queues_max = DFLT_QUEUESMAX;
1253 ns->mq_msg_max = DFLT_MSGMAX;
1254 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1255
1256 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1257 if (IS_ERR(ns->mq_mnt)) {
1258 int err = PTR_ERR(ns->mq_mnt);
1259 ns->mq_mnt = NULL;
1260 return err;
1261 }
1262 return 0;
1263}
1264
1265void mq_clear_sbinfo(struct ipc_namespace *ns)
1266{
1267 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1268}
1269
1270void mq_put_mnt(struct ipc_namespace *ns)
1271{
1272 mntput(ns->mq_mnt);
1273}
1274
1275static int __init init_mqueue_fs(void)
1276{
1277 int error;
1278
1279 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1280 sizeof(struct mqueue_inode_info), 0,
1281 SLAB_HWCACHE_ALIGN, init_once);
1282 if (mqueue_inode_cachep == NULL)
1283 return -ENOMEM;
1284
1285 /* ignore failures - they are not fatal */
1286 mq_sysctl_table = mq_register_sysctl_table();
1287
1288 error = register_filesystem(&mqueue_fs_type);
1289 if (error)
1290 goto out_sysctl;
1291
1292 spin_lock_init(&mq_lock);
1293
1294 init_ipc_ns.mq_mnt = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);
1295 if (IS_ERR(init_ipc_ns.mq_mnt)) {
1296 error = PTR_ERR(init_ipc_ns.mq_mnt);
1297 goto out_filesystem;
1298 }
1299
1300 return 0;
1301
1302out_filesystem:
1303 unregister_filesystem(&mqueue_fs_type);
1304out_sysctl:
1305 if (mq_sysctl_table)
1306 unregister_sysctl_table(mq_sysctl_table);
1307 kmem_cache_destroy(mqueue_inode_cachep);
1308 return error;
1309}
1310
1311__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
66/*
67 * Locking:
68 *
69 * Accesses to a message queue are synchronized by acquiring info->lock.
70 *
71 * There are two notable exceptions:
72 * - The actual wakeup of a sleeping task is performed using the wake_q
73 * framework. info->lock is already released when wake_up_q is called.
74 * - The exit codepaths after sleeping check ext_wait_queue->state without
75 * any locks. If it is STATE_READY, then the syscall is completed without
76 * acquiring info->lock.
77 *
78 * MQ_BARRIER:
79 * To achieve proper release/acquire memory barrier pairing, the state is set to
80 * STATE_READY with smp_store_release(), and it is read with READ_ONCE followed
81 * by smp_acquire__after_ctrl_dep(). In addition, wake_q_add_safe() is used.
82 *
83 * This prevents the following races:
84 *
85 * 1) With the simple wake_q_add(), the task could be gone already before
86 * the increase of the reference happens
87 * Thread A
88 * Thread B
89 * WRITE_ONCE(wait.state, STATE_NONE);
90 * schedule_hrtimeout()
91 * wake_q_add(A)
92 * if (cmpxchg()) // success
93 * ->state = STATE_READY (reordered)
94 * <timeout returns>
95 * if (wait.state == STATE_READY) return;
96 * sysret to user space
97 * sys_exit()
98 * get_task_struct() // UaF
99 *
100 * Solution: Use wake_q_add_safe() and perform the get_task_struct() before
101 * the smp_store_release() that does ->state = STATE_READY.
102 *
103 * 2) Without proper _release/_acquire barriers, the woken up task
104 * could read stale data
105 *
106 * Thread A
107 * Thread B
108 * do_mq_timedreceive
109 * WRITE_ONCE(wait.state, STATE_NONE);
110 * schedule_hrtimeout()
111 * state = STATE_READY;
112 * <timeout returns>
113 * if (wait.state == STATE_READY) return;
114 * msg_ptr = wait.msg; // Access to stale data!
115 * receiver->msg = message; (reordered)
116 *
117 * Solution: use _release and _acquire barriers.
118 *
119 * 3) There is intentionally no barrier when setting current->state
120 * to TASK_INTERRUPTIBLE: spin_unlock(&info->lock) provides the
121 * release memory barrier, and the wakeup is triggered when holding
122 * info->lock, i.e. spin_lock(&info->lock) provided a pairing
123 * acquire memory barrier.
124 */
125
126struct ext_wait_queue { /* queue of sleeping tasks */
127 struct task_struct *task;
128 struct list_head list;
129 struct msg_msg *msg; /* ptr of loaded message */
130 int state; /* one of STATE_* values */
131};
132
133struct mqueue_inode_info {
134 spinlock_t lock;
135 struct inode vfs_inode;
136 wait_queue_head_t wait_q;
137
138 struct rb_root msg_tree;
139 struct rb_node *msg_tree_rightmost;
140 struct posix_msg_tree_node *node_cache;
141 struct mq_attr attr;
142
143 struct sigevent notify;
144 struct pid *notify_owner;
145 u32 notify_self_exec_id;
146 struct user_namespace *notify_user_ns;
147 struct user_struct *user; /* user who created, for accounting */
148 struct sock *notify_sock;
149 struct sk_buff *notify_cookie;
150
151 /* for tasks waiting for free space and messages, respectively */
152 struct ext_wait_queue e_wait_q[2];
153
154 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
155};
156
157static struct file_system_type mqueue_fs_type;
158static const struct inode_operations mqueue_dir_inode_operations;
159static const struct file_operations mqueue_file_operations;
160static const struct super_operations mqueue_super_ops;
161static const struct fs_context_operations mqueue_fs_context_ops;
162static void remove_notification(struct mqueue_inode_info *info);
163
164static struct kmem_cache *mqueue_inode_cachep;
165
166static struct ctl_table_header *mq_sysctl_table;
167
168static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
169{
170 return container_of(inode, struct mqueue_inode_info, vfs_inode);
171}
172
173/*
174 * This routine should be called with the mq_lock held.
175 */
176static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
177{
178 return get_ipc_ns(inode->i_sb->s_fs_info);
179}
180
181static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
182{
183 struct ipc_namespace *ns;
184
185 spin_lock(&mq_lock);
186 ns = __get_ns_from_inode(inode);
187 spin_unlock(&mq_lock);
188 return ns;
189}
190
191/* Auxiliary functions to manipulate messages' list */
192static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
193{
194 struct rb_node **p, *parent = NULL;
195 struct posix_msg_tree_node *leaf;
196 bool rightmost = true;
197
198 p = &info->msg_tree.rb_node;
199 while (*p) {
200 parent = *p;
201 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
202
203 if (likely(leaf->priority == msg->m_type))
204 goto insert_msg;
205 else if (msg->m_type < leaf->priority) {
206 p = &(*p)->rb_left;
207 rightmost = false;
208 } else
209 p = &(*p)->rb_right;
210 }
211 if (info->node_cache) {
212 leaf = info->node_cache;
213 info->node_cache = NULL;
214 } else {
215 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
216 if (!leaf)
217 return -ENOMEM;
218 INIT_LIST_HEAD(&leaf->msg_list);
219 }
220 leaf->priority = msg->m_type;
221
222 if (rightmost)
223 info->msg_tree_rightmost = &leaf->rb_node;
224
225 rb_link_node(&leaf->rb_node, parent, p);
226 rb_insert_color(&leaf->rb_node, &info->msg_tree);
227insert_msg:
228 info->attr.mq_curmsgs++;
229 info->qsize += msg->m_ts;
230 list_add_tail(&msg->m_list, &leaf->msg_list);
231 return 0;
232}
233
234static inline void msg_tree_erase(struct posix_msg_tree_node *leaf,
235 struct mqueue_inode_info *info)
236{
237 struct rb_node *node = &leaf->rb_node;
238
239 if (info->msg_tree_rightmost == node)
240 info->msg_tree_rightmost = rb_prev(node);
241
242 rb_erase(node, &info->msg_tree);
243 if (info->node_cache)
244 kfree(leaf);
245 else
246 info->node_cache = leaf;
247}
248
249static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
250{
251 struct rb_node *parent = NULL;
252 struct posix_msg_tree_node *leaf;
253 struct msg_msg *msg;
254
255try_again:
256 /*
257 * During insert, low priorities go to the left and high to the
258 * right. On receive, we want the highest priorities first, so
259 * walk all the way to the right.
260 */
261 parent = info->msg_tree_rightmost;
262 if (!parent) {
263 if (info->attr.mq_curmsgs) {
264 pr_warn_once("Inconsistency in POSIX message queue, "
265 "no tree element, but supposedly messages "
266 "should exist!\n");
267 info->attr.mq_curmsgs = 0;
268 }
269 return NULL;
270 }
271 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
272 if (unlikely(list_empty(&leaf->msg_list))) {
273 pr_warn_once("Inconsistency in POSIX message queue, "
274 "empty leaf node but we haven't implemented "
275 "lazy leaf delete!\n");
276 msg_tree_erase(leaf, info);
277 goto try_again;
278 } else {
279 msg = list_first_entry(&leaf->msg_list,
280 struct msg_msg, m_list);
281 list_del(&msg->m_list);
282 if (list_empty(&leaf->msg_list)) {
283 msg_tree_erase(leaf, info);
284 }
285 }
286 info->attr.mq_curmsgs--;
287 info->qsize -= msg->m_ts;
288 return msg;
289}
290
291static struct inode *mqueue_get_inode(struct super_block *sb,
292 struct ipc_namespace *ipc_ns, umode_t mode,
293 struct mq_attr *attr)
294{
295 struct user_struct *u = current_user();
296 struct inode *inode;
297 int ret = -ENOMEM;
298
299 inode = new_inode(sb);
300 if (!inode)
301 goto err;
302
303 inode->i_ino = get_next_ino();
304 inode->i_mode = mode;
305 inode->i_uid = current_fsuid();
306 inode->i_gid = current_fsgid();
307 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
308
309 if (S_ISREG(mode)) {
310 struct mqueue_inode_info *info;
311 unsigned long mq_bytes, mq_treesize;
312
313 inode->i_fop = &mqueue_file_operations;
314 inode->i_size = FILENT_SIZE;
315 /* mqueue specific info */
316 info = MQUEUE_I(inode);
317 spin_lock_init(&info->lock);
318 init_waitqueue_head(&info->wait_q);
319 INIT_LIST_HEAD(&info->e_wait_q[0].list);
320 INIT_LIST_HEAD(&info->e_wait_q[1].list);
321 info->notify_owner = NULL;
322 info->notify_user_ns = NULL;
323 info->qsize = 0;
324 info->user = NULL; /* set when all is ok */
325 info->msg_tree = RB_ROOT;
326 info->msg_tree_rightmost = NULL;
327 info->node_cache = NULL;
328 memset(&info->attr, 0, sizeof(info->attr));
329 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
330 ipc_ns->mq_msg_default);
331 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
332 ipc_ns->mq_msgsize_default);
333 if (attr) {
334 info->attr.mq_maxmsg = attr->mq_maxmsg;
335 info->attr.mq_msgsize = attr->mq_msgsize;
336 }
337 /*
338 * We used to allocate a static array of pointers and account
339 * the size of that array as well as one msg_msg struct per
340 * possible message into the queue size. That's no longer
341 * accurate as the queue is now an rbtree and will grow and
342 * shrink depending on usage patterns. We can, however, still
343 * account one msg_msg struct per message, but the nodes are
344 * allocated depending on priority usage, and most programs
345 * only use one, or a handful, of priorities. However, since
346 * this is pinned memory, we need to assume worst case, so
347 * that means the min(mq_maxmsg, max_priorities) * struct
348 * posix_msg_tree_node.
349 */
350
351 ret = -EINVAL;
352 if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
353 goto out_inode;
354 if (capable(CAP_SYS_RESOURCE)) {
355 if (info->attr.mq_maxmsg > HARD_MSGMAX ||
356 info->attr.mq_msgsize > HARD_MSGSIZEMAX)
357 goto out_inode;
358 } else {
359 if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
360 info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
361 goto out_inode;
362 }
363 ret = -EOVERFLOW;
364 /* check for overflow */
365 if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
366 goto out_inode;
367 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
368 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
369 sizeof(struct posix_msg_tree_node);
370 mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
371 if (mq_bytes + mq_treesize < mq_bytes)
372 goto out_inode;
373 mq_bytes += mq_treesize;
374 spin_lock(&mq_lock);
375 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
376 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
377 spin_unlock(&mq_lock);
378 /* mqueue_evict_inode() releases info->messages */
379 ret = -EMFILE;
380 goto out_inode;
381 }
382 u->mq_bytes += mq_bytes;
383 spin_unlock(&mq_lock);
384
385 /* all is ok */
386 info->user = get_uid(u);
387 } else if (S_ISDIR(mode)) {
388 inc_nlink(inode);
389 /* Some things misbehave if size == 0 on a directory */
390 inode->i_size = 2 * DIRENT_SIZE;
391 inode->i_op = &mqueue_dir_inode_operations;
392 inode->i_fop = &simple_dir_operations;
393 }
394
395 return inode;
396out_inode:
397 iput(inode);
398err:
399 return ERR_PTR(ret);
400}
401
402static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc)
403{
404 struct inode *inode;
405 struct ipc_namespace *ns = sb->s_fs_info;
406
407 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
408 sb->s_blocksize = PAGE_SIZE;
409 sb->s_blocksize_bits = PAGE_SHIFT;
410 sb->s_magic = MQUEUE_MAGIC;
411 sb->s_op = &mqueue_super_ops;
412
413 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
414 if (IS_ERR(inode))
415 return PTR_ERR(inode);
416
417 sb->s_root = d_make_root(inode);
418 if (!sb->s_root)
419 return -ENOMEM;
420 return 0;
421}
422
423static int mqueue_get_tree(struct fs_context *fc)
424{
425 struct mqueue_fs_context *ctx = fc->fs_private;
426
427 return get_tree_keyed(fc, mqueue_fill_super, ctx->ipc_ns);
428}
429
430static void mqueue_fs_context_free(struct fs_context *fc)
431{
432 struct mqueue_fs_context *ctx = fc->fs_private;
433
434 put_ipc_ns(ctx->ipc_ns);
435 kfree(ctx);
436}
437
438static int mqueue_init_fs_context(struct fs_context *fc)
439{
440 struct mqueue_fs_context *ctx;
441
442 ctx = kzalloc(sizeof(struct mqueue_fs_context), GFP_KERNEL);
443 if (!ctx)
444 return -ENOMEM;
445
446 ctx->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
447 put_user_ns(fc->user_ns);
448 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
449 fc->fs_private = ctx;
450 fc->ops = &mqueue_fs_context_ops;
451 return 0;
452}
453
454static struct vfsmount *mq_create_mount(struct ipc_namespace *ns)
455{
456 struct mqueue_fs_context *ctx;
457 struct fs_context *fc;
458 struct vfsmount *mnt;
459
460 fc = fs_context_for_mount(&mqueue_fs_type, SB_KERNMOUNT);
461 if (IS_ERR(fc))
462 return ERR_CAST(fc);
463
464 ctx = fc->fs_private;
465 put_ipc_ns(ctx->ipc_ns);
466 ctx->ipc_ns = get_ipc_ns(ns);
467 put_user_ns(fc->user_ns);
468 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
469
470 mnt = fc_mount(fc);
471 put_fs_context(fc);
472 return mnt;
473}
474
475static void init_once(void *foo)
476{
477 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
478
479 inode_init_once(&p->vfs_inode);
480}
481
482static struct inode *mqueue_alloc_inode(struct super_block *sb)
483{
484 struct mqueue_inode_info *ei;
485
486 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
487 if (!ei)
488 return NULL;
489 return &ei->vfs_inode;
490}
491
492static void mqueue_free_inode(struct inode *inode)
493{
494 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
495}
496
497static void mqueue_evict_inode(struct inode *inode)
498{
499 struct mqueue_inode_info *info;
500 struct user_struct *user;
501 struct ipc_namespace *ipc_ns;
502 struct msg_msg *msg, *nmsg;
503 LIST_HEAD(tmp_msg);
504
505 clear_inode(inode);
506
507 if (S_ISDIR(inode->i_mode))
508 return;
509
510 ipc_ns = get_ns_from_inode(inode);
511 info = MQUEUE_I(inode);
512 spin_lock(&info->lock);
513 while ((msg = msg_get(info)) != NULL)
514 list_add_tail(&msg->m_list, &tmp_msg);
515 kfree(info->node_cache);
516 spin_unlock(&info->lock);
517
518 list_for_each_entry_safe(msg, nmsg, &tmp_msg, m_list) {
519 list_del(&msg->m_list);
520 free_msg(msg);
521 }
522
523 user = info->user;
524 if (user) {
525 unsigned long mq_bytes, mq_treesize;
526
527 /* Total amount of bytes accounted for the mqueue */
528 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
529 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
530 sizeof(struct posix_msg_tree_node);
531
532 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
533 info->attr.mq_msgsize);
534
535 spin_lock(&mq_lock);
536 user->mq_bytes -= mq_bytes;
537 /*
538 * get_ns_from_inode() ensures that the
539 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
540 * to which we now hold a reference, or it is NULL.
541 * We can't put it here under mq_lock, though.
542 */
543 if (ipc_ns)
544 ipc_ns->mq_queues_count--;
545 spin_unlock(&mq_lock);
546 free_uid(user);
547 }
548 if (ipc_ns)
549 put_ipc_ns(ipc_ns);
550}
551
552static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
553{
554 struct inode *dir = dentry->d_parent->d_inode;
555 struct inode *inode;
556 struct mq_attr *attr = arg;
557 int error;
558 struct ipc_namespace *ipc_ns;
559
560 spin_lock(&mq_lock);
561 ipc_ns = __get_ns_from_inode(dir);
562 if (!ipc_ns) {
563 error = -EACCES;
564 goto out_unlock;
565 }
566
567 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
568 !capable(CAP_SYS_RESOURCE)) {
569 error = -ENOSPC;
570 goto out_unlock;
571 }
572 ipc_ns->mq_queues_count++;
573 spin_unlock(&mq_lock);
574
575 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
576 if (IS_ERR(inode)) {
577 error = PTR_ERR(inode);
578 spin_lock(&mq_lock);
579 ipc_ns->mq_queues_count--;
580 goto out_unlock;
581 }
582
583 put_ipc_ns(ipc_ns);
584 dir->i_size += DIRENT_SIZE;
585 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
586
587 d_instantiate(dentry, inode);
588 dget(dentry);
589 return 0;
590out_unlock:
591 spin_unlock(&mq_lock);
592 if (ipc_ns)
593 put_ipc_ns(ipc_ns);
594 return error;
595}
596
597static int mqueue_create(struct inode *dir, struct dentry *dentry,
598 umode_t mode, bool excl)
599{
600 return mqueue_create_attr(dentry, mode, NULL);
601}
602
603static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
604{
605 struct inode *inode = d_inode(dentry);
606
607 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
608 dir->i_size -= DIRENT_SIZE;
609 drop_nlink(inode);
610 dput(dentry);
611 return 0;
612}
613
614/*
615* This is routine for system read from queue file.
616* To avoid mess with doing here some sort of mq_receive we allow
617* to read only queue size & notification info (the only values
618* that are interesting from user point of view and aren't accessible
619* through std routines)
620*/
621static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
622 size_t count, loff_t *off)
623{
624 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
625 char buffer[FILENT_SIZE];
626 ssize_t ret;
627
628 spin_lock(&info->lock);
629 snprintf(buffer, sizeof(buffer),
630 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
631 info->qsize,
632 info->notify_owner ? info->notify.sigev_notify : 0,
633 (info->notify_owner &&
634 info->notify.sigev_notify == SIGEV_SIGNAL) ?
635 info->notify.sigev_signo : 0,
636 pid_vnr(info->notify_owner));
637 spin_unlock(&info->lock);
638 buffer[sizeof(buffer)-1] = '\0';
639
640 ret = simple_read_from_buffer(u_data, count, off, buffer,
641 strlen(buffer));
642 if (ret <= 0)
643 return ret;
644
645 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
646 return ret;
647}
648
649static int mqueue_flush_file(struct file *filp, fl_owner_t id)
650{
651 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
652
653 spin_lock(&info->lock);
654 if (task_tgid(current) == info->notify_owner)
655 remove_notification(info);
656
657 spin_unlock(&info->lock);
658 return 0;
659}
660
661static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
662{
663 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
664 __poll_t retval = 0;
665
666 poll_wait(filp, &info->wait_q, poll_tab);
667
668 spin_lock(&info->lock);
669 if (info->attr.mq_curmsgs)
670 retval = EPOLLIN | EPOLLRDNORM;
671
672 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
673 retval |= EPOLLOUT | EPOLLWRNORM;
674 spin_unlock(&info->lock);
675
676 return retval;
677}
678
679/* Adds current to info->e_wait_q[sr] before element with smaller prio */
680static void wq_add(struct mqueue_inode_info *info, int sr,
681 struct ext_wait_queue *ewp)
682{
683 struct ext_wait_queue *walk;
684
685 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
686 if (walk->task->prio <= current->prio) {
687 list_add_tail(&ewp->list, &walk->list);
688 return;
689 }
690 }
691 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
692}
693
694/*
695 * Puts current task to sleep. Caller must hold queue lock. After return
696 * lock isn't held.
697 * sr: SEND or RECV
698 */
699static int wq_sleep(struct mqueue_inode_info *info, int sr,
700 ktime_t *timeout, struct ext_wait_queue *ewp)
701 __releases(&info->lock)
702{
703 int retval;
704 signed long time;
705
706 wq_add(info, sr, ewp);
707
708 for (;;) {
709 /* memory barrier not required, we hold info->lock */
710 __set_current_state(TASK_INTERRUPTIBLE);
711
712 spin_unlock(&info->lock);
713 time = schedule_hrtimeout_range_clock(timeout, 0,
714 HRTIMER_MODE_ABS, CLOCK_REALTIME);
715
716 if (READ_ONCE(ewp->state) == STATE_READY) {
717 /* see MQ_BARRIER for purpose/pairing */
718 smp_acquire__after_ctrl_dep();
719 retval = 0;
720 goto out;
721 }
722 spin_lock(&info->lock);
723
724 /* we hold info->lock, so no memory barrier required */
725 if (READ_ONCE(ewp->state) == STATE_READY) {
726 retval = 0;
727 goto out_unlock;
728 }
729 if (signal_pending(current)) {
730 retval = -ERESTARTSYS;
731 break;
732 }
733 if (time == 0) {
734 retval = -ETIMEDOUT;
735 break;
736 }
737 }
738 list_del(&ewp->list);
739out_unlock:
740 spin_unlock(&info->lock);
741out:
742 return retval;
743}
744
745/*
746 * Returns waiting task that should be serviced first or NULL if none exists
747 */
748static struct ext_wait_queue *wq_get_first_waiter(
749 struct mqueue_inode_info *info, int sr)
750{
751 struct list_head *ptr;
752
753 ptr = info->e_wait_q[sr].list.prev;
754 if (ptr == &info->e_wait_q[sr].list)
755 return NULL;
756 return list_entry(ptr, struct ext_wait_queue, list);
757}
758
759
760static inline void set_cookie(struct sk_buff *skb, char code)
761{
762 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
763}
764
765/*
766 * The next function is only to split too long sys_mq_timedsend
767 */
768static void __do_notify(struct mqueue_inode_info *info)
769{
770 /* notification
771 * invoked when there is registered process and there isn't process
772 * waiting synchronously for message AND state of queue changed from
773 * empty to not empty. Here we are sure that no one is waiting
774 * synchronously. */
775 if (info->notify_owner &&
776 info->attr.mq_curmsgs == 1) {
777 switch (info->notify.sigev_notify) {
778 case SIGEV_NONE:
779 break;
780 case SIGEV_SIGNAL: {
781 struct kernel_siginfo sig_i;
782 struct task_struct *task;
783
784 /* do_mq_notify() accepts sigev_signo == 0, why?? */
785 if (!info->notify.sigev_signo)
786 break;
787
788 clear_siginfo(&sig_i);
789 sig_i.si_signo = info->notify.sigev_signo;
790 sig_i.si_errno = 0;
791 sig_i.si_code = SI_MESGQ;
792 sig_i.si_value = info->notify.sigev_value;
793 rcu_read_lock();
794 /* map current pid/uid into info->owner's namespaces */
795 sig_i.si_pid = task_tgid_nr_ns(current,
796 ns_of_pid(info->notify_owner));
797 sig_i.si_uid = from_kuid_munged(info->notify_user_ns,
798 current_uid());
799 /*
800 * We can't use kill_pid_info(), this signal should
801 * bypass check_kill_permission(). It is from kernel
802 * but si_fromuser() can't know this.
803 * We do check the self_exec_id, to avoid sending
804 * signals to programs that don't expect them.
805 */
806 task = pid_task(info->notify_owner, PIDTYPE_TGID);
807 if (task && task->self_exec_id ==
808 info->notify_self_exec_id) {
809 do_send_sig_info(info->notify.sigev_signo,
810 &sig_i, task, PIDTYPE_TGID);
811 }
812 rcu_read_unlock();
813 break;
814 }
815 case SIGEV_THREAD:
816 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
817 netlink_sendskb(info->notify_sock, info->notify_cookie);
818 break;
819 }
820 /* after notification unregisters process */
821 put_pid(info->notify_owner);
822 put_user_ns(info->notify_user_ns);
823 info->notify_owner = NULL;
824 info->notify_user_ns = NULL;
825 }
826 wake_up(&info->wait_q);
827}
828
829static int prepare_timeout(const struct __kernel_timespec __user *u_abs_timeout,
830 struct timespec64 *ts)
831{
832 if (get_timespec64(ts, u_abs_timeout))
833 return -EFAULT;
834 if (!timespec64_valid(ts))
835 return -EINVAL;
836 return 0;
837}
838
839static void remove_notification(struct mqueue_inode_info *info)
840{
841 if (info->notify_owner != NULL &&
842 info->notify.sigev_notify == SIGEV_THREAD) {
843 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
844 netlink_sendskb(info->notify_sock, info->notify_cookie);
845 }
846 put_pid(info->notify_owner);
847 put_user_ns(info->notify_user_ns);
848 info->notify_owner = NULL;
849 info->notify_user_ns = NULL;
850}
851
852static int prepare_open(struct dentry *dentry, int oflag, int ro,
853 umode_t mode, struct filename *name,
854 struct mq_attr *attr)
855{
856 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
857 MAY_READ | MAY_WRITE };
858 int acc;
859
860 if (d_really_is_negative(dentry)) {
861 if (!(oflag & O_CREAT))
862 return -ENOENT;
863 if (ro)
864 return ro;
865 audit_inode_parent_hidden(name, dentry->d_parent);
866 return vfs_mkobj(dentry, mode & ~current_umask(),
867 mqueue_create_attr, attr);
868 }
869 /* it already existed */
870 audit_inode(name, dentry, 0);
871 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
872 return -EEXIST;
873 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
874 return -EINVAL;
875 acc = oflag2acc[oflag & O_ACCMODE];
876 return inode_permission(d_inode(dentry), acc);
877}
878
879static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
880 struct mq_attr *attr)
881{
882 struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
883 struct dentry *root = mnt->mnt_root;
884 struct filename *name;
885 struct path path;
886 int fd, error;
887 int ro;
888
889 audit_mq_open(oflag, mode, attr);
890
891 if (IS_ERR(name = getname(u_name)))
892 return PTR_ERR(name);
893
894 fd = get_unused_fd_flags(O_CLOEXEC);
895 if (fd < 0)
896 goto out_putname;
897
898 ro = mnt_want_write(mnt); /* we'll drop it in any case */
899 inode_lock(d_inode(root));
900 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
901 if (IS_ERR(path.dentry)) {
902 error = PTR_ERR(path.dentry);
903 goto out_putfd;
904 }
905 path.mnt = mntget(mnt);
906 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
907 if (!error) {
908 struct file *file = dentry_open(&path, oflag, current_cred());
909 if (!IS_ERR(file))
910 fd_install(fd, file);
911 else
912 error = PTR_ERR(file);
913 }
914 path_put(&path);
915out_putfd:
916 if (error) {
917 put_unused_fd(fd);
918 fd = error;
919 }
920 inode_unlock(d_inode(root));
921 if (!ro)
922 mnt_drop_write(mnt);
923out_putname:
924 putname(name);
925 return fd;
926}
927
928SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
929 struct mq_attr __user *, u_attr)
930{
931 struct mq_attr attr;
932 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
933 return -EFAULT;
934
935 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
936}
937
938SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
939{
940 int err;
941 struct filename *name;
942 struct dentry *dentry;
943 struct inode *inode = NULL;
944 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
945 struct vfsmount *mnt = ipc_ns->mq_mnt;
946
947 name = getname(u_name);
948 if (IS_ERR(name))
949 return PTR_ERR(name);
950
951 audit_inode_parent_hidden(name, mnt->mnt_root);
952 err = mnt_want_write(mnt);
953 if (err)
954 goto out_name;
955 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
956 dentry = lookup_one_len(name->name, mnt->mnt_root,
957 strlen(name->name));
958 if (IS_ERR(dentry)) {
959 err = PTR_ERR(dentry);
960 goto out_unlock;
961 }
962
963 inode = d_inode(dentry);
964 if (!inode) {
965 err = -ENOENT;
966 } else {
967 ihold(inode);
968 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
969 }
970 dput(dentry);
971
972out_unlock:
973 inode_unlock(d_inode(mnt->mnt_root));
974 if (inode)
975 iput(inode);
976 mnt_drop_write(mnt);
977out_name:
978 putname(name);
979
980 return err;
981}
982
983/* Pipelined send and receive functions.
984 *
985 * If a receiver finds no waiting message, then it registers itself in the
986 * list of waiting receivers. A sender checks that list before adding the new
987 * message into the message array. If there is a waiting receiver, then it
988 * bypasses the message array and directly hands the message over to the
989 * receiver. The receiver accepts the message and returns without grabbing the
990 * queue spinlock:
991 *
992 * - Set pointer to message.
993 * - Queue the receiver task for later wakeup (without the info->lock).
994 * - Update its state to STATE_READY. Now the receiver can continue.
995 * - Wake up the process after the lock is dropped. Should the process wake up
996 * before this wakeup (due to a timeout or a signal) it will either see
997 * STATE_READY and continue or acquire the lock to check the state again.
998 *
999 * The same algorithm is used for senders.
1000 */
1001
1002static inline void __pipelined_op(struct wake_q_head *wake_q,
1003 struct mqueue_inode_info *info,
1004 struct ext_wait_queue *this)
1005{
1006 list_del(&this->list);
1007 get_task_struct(this->task);
1008
1009 /* see MQ_BARRIER for purpose/pairing */
1010 smp_store_release(&this->state, STATE_READY);
1011 wake_q_add_safe(wake_q, this->task);
1012}
1013
1014/* pipelined_send() - send a message directly to the task waiting in
1015 * sys_mq_timedreceive() (without inserting message into a queue).
1016 */
1017static inline void pipelined_send(struct wake_q_head *wake_q,
1018 struct mqueue_inode_info *info,
1019 struct msg_msg *message,
1020 struct ext_wait_queue *receiver)
1021{
1022 receiver->msg = message;
1023 __pipelined_op(wake_q, info, receiver);
1024}
1025
1026/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
1027 * gets its message and put to the queue (we have one free place for sure). */
1028static inline void pipelined_receive(struct wake_q_head *wake_q,
1029 struct mqueue_inode_info *info)
1030{
1031 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
1032
1033 if (!sender) {
1034 /* for poll */
1035 wake_up_interruptible(&info->wait_q);
1036 return;
1037 }
1038 if (msg_insert(sender->msg, info))
1039 return;
1040
1041 __pipelined_op(wake_q, info, sender);
1042}
1043
1044static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
1045 size_t msg_len, unsigned int msg_prio,
1046 struct timespec64 *ts)
1047{
1048 struct fd f;
1049 struct inode *inode;
1050 struct ext_wait_queue wait;
1051 struct ext_wait_queue *receiver;
1052 struct msg_msg *msg_ptr;
1053 struct mqueue_inode_info *info;
1054 ktime_t expires, *timeout = NULL;
1055 struct posix_msg_tree_node *new_leaf = NULL;
1056 int ret = 0;
1057 DEFINE_WAKE_Q(wake_q);
1058
1059 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
1060 return -EINVAL;
1061
1062 if (ts) {
1063 expires = timespec64_to_ktime(*ts);
1064 timeout = &expires;
1065 }
1066
1067 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
1068
1069 f = fdget(mqdes);
1070 if (unlikely(!f.file)) {
1071 ret = -EBADF;
1072 goto out;
1073 }
1074
1075 inode = file_inode(f.file);
1076 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1077 ret = -EBADF;
1078 goto out_fput;
1079 }
1080 info = MQUEUE_I(inode);
1081 audit_file(f.file);
1082
1083 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
1084 ret = -EBADF;
1085 goto out_fput;
1086 }
1087
1088 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1089 ret = -EMSGSIZE;
1090 goto out_fput;
1091 }
1092
1093 /* First try to allocate memory, before doing anything with
1094 * existing queues. */
1095 msg_ptr = load_msg(u_msg_ptr, msg_len);
1096 if (IS_ERR(msg_ptr)) {
1097 ret = PTR_ERR(msg_ptr);
1098 goto out_fput;
1099 }
1100 msg_ptr->m_ts = msg_len;
1101 msg_ptr->m_type = msg_prio;
1102
1103 /*
1104 * msg_insert really wants us to have a valid, spare node struct so
1105 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1106 * fall back to that if necessary.
1107 */
1108 if (!info->node_cache)
1109 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1110
1111 spin_lock(&info->lock);
1112
1113 if (!info->node_cache && new_leaf) {
1114 /* Save our speculative allocation into the cache */
1115 INIT_LIST_HEAD(&new_leaf->msg_list);
1116 info->node_cache = new_leaf;
1117 new_leaf = NULL;
1118 } else {
1119 kfree(new_leaf);
1120 }
1121
1122 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1123 if (f.file->f_flags & O_NONBLOCK) {
1124 ret = -EAGAIN;
1125 } else {
1126 wait.task = current;
1127 wait.msg = (void *) msg_ptr;
1128
1129 /* memory barrier not required, we hold info->lock */
1130 WRITE_ONCE(wait.state, STATE_NONE);
1131 ret = wq_sleep(info, SEND, timeout, &wait);
1132 /*
1133 * wq_sleep must be called with info->lock held, and
1134 * returns with the lock released
1135 */
1136 goto out_free;
1137 }
1138 } else {
1139 receiver = wq_get_first_waiter(info, RECV);
1140 if (receiver) {
1141 pipelined_send(&wake_q, info, msg_ptr, receiver);
1142 } else {
1143 /* adds message to the queue */
1144 ret = msg_insert(msg_ptr, info);
1145 if (ret)
1146 goto out_unlock;
1147 __do_notify(info);
1148 }
1149 inode->i_atime = inode->i_mtime = inode->i_ctime =
1150 current_time(inode);
1151 }
1152out_unlock:
1153 spin_unlock(&info->lock);
1154 wake_up_q(&wake_q);
1155out_free:
1156 if (ret)
1157 free_msg(msg_ptr);
1158out_fput:
1159 fdput(f);
1160out:
1161 return ret;
1162}
1163
1164static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1165 size_t msg_len, unsigned int __user *u_msg_prio,
1166 struct timespec64 *ts)
1167{
1168 ssize_t ret;
1169 struct msg_msg *msg_ptr;
1170 struct fd f;
1171 struct inode *inode;
1172 struct mqueue_inode_info *info;
1173 struct ext_wait_queue wait;
1174 ktime_t expires, *timeout = NULL;
1175 struct posix_msg_tree_node *new_leaf = NULL;
1176
1177 if (ts) {
1178 expires = timespec64_to_ktime(*ts);
1179 timeout = &expires;
1180 }
1181
1182 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1183
1184 f = fdget(mqdes);
1185 if (unlikely(!f.file)) {
1186 ret = -EBADF;
1187 goto out;
1188 }
1189
1190 inode = file_inode(f.file);
1191 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1192 ret = -EBADF;
1193 goto out_fput;
1194 }
1195 info = MQUEUE_I(inode);
1196 audit_file(f.file);
1197
1198 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1199 ret = -EBADF;
1200 goto out_fput;
1201 }
1202
1203 /* checks if buffer is big enough */
1204 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1205 ret = -EMSGSIZE;
1206 goto out_fput;
1207 }
1208
1209 /*
1210 * msg_insert really wants us to have a valid, spare node struct so
1211 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1212 * fall back to that if necessary.
1213 */
1214 if (!info->node_cache)
1215 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1216
1217 spin_lock(&info->lock);
1218
1219 if (!info->node_cache && new_leaf) {
1220 /* Save our speculative allocation into the cache */
1221 INIT_LIST_HEAD(&new_leaf->msg_list);
1222 info->node_cache = new_leaf;
1223 } else {
1224 kfree(new_leaf);
1225 }
1226
1227 if (info->attr.mq_curmsgs == 0) {
1228 if (f.file->f_flags & O_NONBLOCK) {
1229 spin_unlock(&info->lock);
1230 ret = -EAGAIN;
1231 } else {
1232 wait.task = current;
1233
1234 /* memory barrier not required, we hold info->lock */
1235 WRITE_ONCE(wait.state, STATE_NONE);
1236 ret = wq_sleep(info, RECV, timeout, &wait);
1237 msg_ptr = wait.msg;
1238 }
1239 } else {
1240 DEFINE_WAKE_Q(wake_q);
1241
1242 msg_ptr = msg_get(info);
1243
1244 inode->i_atime = inode->i_mtime = inode->i_ctime =
1245 current_time(inode);
1246
1247 /* There is now free space in queue. */
1248 pipelined_receive(&wake_q, info);
1249 spin_unlock(&info->lock);
1250 wake_up_q(&wake_q);
1251 ret = 0;
1252 }
1253 if (ret == 0) {
1254 ret = msg_ptr->m_ts;
1255
1256 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1257 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1258 ret = -EFAULT;
1259 }
1260 free_msg(msg_ptr);
1261 }
1262out_fput:
1263 fdput(f);
1264out:
1265 return ret;
1266}
1267
1268SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1269 size_t, msg_len, unsigned int, msg_prio,
1270 const struct __kernel_timespec __user *, u_abs_timeout)
1271{
1272 struct timespec64 ts, *p = NULL;
1273 if (u_abs_timeout) {
1274 int res = prepare_timeout(u_abs_timeout, &ts);
1275 if (res)
1276 return res;
1277 p = &ts;
1278 }
1279 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1280}
1281
1282SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1283 size_t, msg_len, unsigned int __user *, u_msg_prio,
1284 const struct __kernel_timespec __user *, u_abs_timeout)
1285{
1286 struct timespec64 ts, *p = NULL;
1287 if (u_abs_timeout) {
1288 int res = prepare_timeout(u_abs_timeout, &ts);
1289 if (res)
1290 return res;
1291 p = &ts;
1292 }
1293 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1294}
1295
1296/*
1297 * Notes: the case when user wants us to deregister (with NULL as pointer)
1298 * and he isn't currently owner of notification, will be silently discarded.
1299 * It isn't explicitly defined in the POSIX.
1300 */
1301static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1302{
1303 int ret;
1304 struct fd f;
1305 struct sock *sock;
1306 struct inode *inode;
1307 struct mqueue_inode_info *info;
1308 struct sk_buff *nc;
1309
1310 audit_mq_notify(mqdes, notification);
1311
1312 nc = NULL;
1313 sock = NULL;
1314 if (notification != NULL) {
1315 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1316 notification->sigev_notify != SIGEV_SIGNAL &&
1317 notification->sigev_notify != SIGEV_THREAD))
1318 return -EINVAL;
1319 if (notification->sigev_notify == SIGEV_SIGNAL &&
1320 !valid_signal(notification->sigev_signo)) {
1321 return -EINVAL;
1322 }
1323 if (notification->sigev_notify == SIGEV_THREAD) {
1324 long timeo;
1325
1326 /* create the notify skb */
1327 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1328 if (!nc)
1329 return -ENOMEM;
1330
1331 if (copy_from_user(nc->data,
1332 notification->sigev_value.sival_ptr,
1333 NOTIFY_COOKIE_LEN)) {
1334 ret = -EFAULT;
1335 goto free_skb;
1336 }
1337
1338 /* TODO: add a header? */
1339 skb_put(nc, NOTIFY_COOKIE_LEN);
1340 /* and attach it to the socket */
1341retry:
1342 f = fdget(notification->sigev_signo);
1343 if (!f.file) {
1344 ret = -EBADF;
1345 goto out;
1346 }
1347 sock = netlink_getsockbyfilp(f.file);
1348 fdput(f);
1349 if (IS_ERR(sock)) {
1350 ret = PTR_ERR(sock);
1351 goto free_skb;
1352 }
1353
1354 timeo = MAX_SCHEDULE_TIMEOUT;
1355 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1356 if (ret == 1) {
1357 sock = NULL;
1358 goto retry;
1359 }
1360 if (ret)
1361 return ret;
1362 }
1363 }
1364
1365 f = fdget(mqdes);
1366 if (!f.file) {
1367 ret = -EBADF;
1368 goto out;
1369 }
1370
1371 inode = file_inode(f.file);
1372 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1373 ret = -EBADF;
1374 goto out_fput;
1375 }
1376 info = MQUEUE_I(inode);
1377
1378 ret = 0;
1379 spin_lock(&info->lock);
1380 if (notification == NULL) {
1381 if (info->notify_owner == task_tgid(current)) {
1382 remove_notification(info);
1383 inode->i_atime = inode->i_ctime = current_time(inode);
1384 }
1385 } else if (info->notify_owner != NULL) {
1386 ret = -EBUSY;
1387 } else {
1388 switch (notification->sigev_notify) {
1389 case SIGEV_NONE:
1390 info->notify.sigev_notify = SIGEV_NONE;
1391 break;
1392 case SIGEV_THREAD:
1393 info->notify_sock = sock;
1394 info->notify_cookie = nc;
1395 sock = NULL;
1396 nc = NULL;
1397 info->notify.sigev_notify = SIGEV_THREAD;
1398 break;
1399 case SIGEV_SIGNAL:
1400 info->notify.sigev_signo = notification->sigev_signo;
1401 info->notify.sigev_value = notification->sigev_value;
1402 info->notify.sigev_notify = SIGEV_SIGNAL;
1403 info->notify_self_exec_id = current->self_exec_id;
1404 break;
1405 }
1406
1407 info->notify_owner = get_pid(task_tgid(current));
1408 info->notify_user_ns = get_user_ns(current_user_ns());
1409 inode->i_atime = inode->i_ctime = current_time(inode);
1410 }
1411 spin_unlock(&info->lock);
1412out_fput:
1413 fdput(f);
1414out:
1415 if (sock)
1416 netlink_detachskb(sock, nc);
1417 else
1418free_skb:
1419 dev_kfree_skb(nc);
1420
1421 return ret;
1422}
1423
1424SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1425 const struct sigevent __user *, u_notification)
1426{
1427 struct sigevent n, *p = NULL;
1428 if (u_notification) {
1429 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1430 return -EFAULT;
1431 p = &n;
1432 }
1433 return do_mq_notify(mqdes, p);
1434}
1435
1436static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1437{
1438 struct fd f;
1439 struct inode *inode;
1440 struct mqueue_inode_info *info;
1441
1442 if (new && (new->mq_flags & (~O_NONBLOCK)))
1443 return -EINVAL;
1444
1445 f = fdget(mqdes);
1446 if (!f.file)
1447 return -EBADF;
1448
1449 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1450 fdput(f);
1451 return -EBADF;
1452 }
1453
1454 inode = file_inode(f.file);
1455 info = MQUEUE_I(inode);
1456
1457 spin_lock(&info->lock);
1458
1459 if (old) {
1460 *old = info->attr;
1461 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1462 }
1463 if (new) {
1464 audit_mq_getsetattr(mqdes, new);
1465 spin_lock(&f.file->f_lock);
1466 if (new->mq_flags & O_NONBLOCK)
1467 f.file->f_flags |= O_NONBLOCK;
1468 else
1469 f.file->f_flags &= ~O_NONBLOCK;
1470 spin_unlock(&f.file->f_lock);
1471
1472 inode->i_atime = inode->i_ctime = current_time(inode);
1473 }
1474
1475 spin_unlock(&info->lock);
1476 fdput(f);
1477 return 0;
1478}
1479
1480SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1481 const struct mq_attr __user *, u_mqstat,
1482 struct mq_attr __user *, u_omqstat)
1483{
1484 int ret;
1485 struct mq_attr mqstat, omqstat;
1486 struct mq_attr *new = NULL, *old = NULL;
1487
1488 if (u_mqstat) {
1489 new = &mqstat;
1490 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1491 return -EFAULT;
1492 }
1493 if (u_omqstat)
1494 old = &omqstat;
1495
1496 ret = do_mq_getsetattr(mqdes, new, old);
1497 if (ret || !old)
1498 return ret;
1499
1500 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1501 return -EFAULT;
1502 return 0;
1503}
1504
1505#ifdef CONFIG_COMPAT
1506
1507struct compat_mq_attr {
1508 compat_long_t mq_flags; /* message queue flags */
1509 compat_long_t mq_maxmsg; /* maximum number of messages */
1510 compat_long_t mq_msgsize; /* maximum message size */
1511 compat_long_t mq_curmsgs; /* number of messages currently queued */
1512 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1513};
1514
1515static inline int get_compat_mq_attr(struct mq_attr *attr,
1516 const struct compat_mq_attr __user *uattr)
1517{
1518 struct compat_mq_attr v;
1519
1520 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1521 return -EFAULT;
1522
1523 memset(attr, 0, sizeof(*attr));
1524 attr->mq_flags = v.mq_flags;
1525 attr->mq_maxmsg = v.mq_maxmsg;
1526 attr->mq_msgsize = v.mq_msgsize;
1527 attr->mq_curmsgs = v.mq_curmsgs;
1528 return 0;
1529}
1530
1531static inline int put_compat_mq_attr(const struct mq_attr *attr,
1532 struct compat_mq_attr __user *uattr)
1533{
1534 struct compat_mq_attr v;
1535
1536 memset(&v, 0, sizeof(v));
1537 v.mq_flags = attr->mq_flags;
1538 v.mq_maxmsg = attr->mq_maxmsg;
1539 v.mq_msgsize = attr->mq_msgsize;
1540 v.mq_curmsgs = attr->mq_curmsgs;
1541 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1542 return -EFAULT;
1543 return 0;
1544}
1545
1546COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1547 int, oflag, compat_mode_t, mode,
1548 struct compat_mq_attr __user *, u_attr)
1549{
1550 struct mq_attr attr, *p = NULL;
1551 if (u_attr && oflag & O_CREAT) {
1552 p = &attr;
1553 if (get_compat_mq_attr(&attr, u_attr))
1554 return -EFAULT;
1555 }
1556 return do_mq_open(u_name, oflag, mode, p);
1557}
1558
1559COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1560 const struct compat_sigevent __user *, u_notification)
1561{
1562 struct sigevent n, *p = NULL;
1563 if (u_notification) {
1564 if (get_compat_sigevent(&n, u_notification))
1565 return -EFAULT;
1566 if (n.sigev_notify == SIGEV_THREAD)
1567 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1568 p = &n;
1569 }
1570 return do_mq_notify(mqdes, p);
1571}
1572
1573COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1574 const struct compat_mq_attr __user *, u_mqstat,
1575 struct compat_mq_attr __user *, u_omqstat)
1576{
1577 int ret;
1578 struct mq_attr mqstat, omqstat;
1579 struct mq_attr *new = NULL, *old = NULL;
1580
1581 if (u_mqstat) {
1582 new = &mqstat;
1583 if (get_compat_mq_attr(new, u_mqstat))
1584 return -EFAULT;
1585 }
1586 if (u_omqstat)
1587 old = &omqstat;
1588
1589 ret = do_mq_getsetattr(mqdes, new, old);
1590 if (ret || !old)
1591 return ret;
1592
1593 if (put_compat_mq_attr(old, u_omqstat))
1594 return -EFAULT;
1595 return 0;
1596}
1597#endif
1598
1599#ifdef CONFIG_COMPAT_32BIT_TIME
1600static int compat_prepare_timeout(const struct old_timespec32 __user *p,
1601 struct timespec64 *ts)
1602{
1603 if (get_old_timespec32(ts, p))
1604 return -EFAULT;
1605 if (!timespec64_valid(ts))
1606 return -EINVAL;
1607 return 0;
1608}
1609
1610SYSCALL_DEFINE5(mq_timedsend_time32, mqd_t, mqdes,
1611 const char __user *, u_msg_ptr,
1612 unsigned int, msg_len, unsigned int, msg_prio,
1613 const struct old_timespec32 __user *, u_abs_timeout)
1614{
1615 struct timespec64 ts, *p = NULL;
1616 if (u_abs_timeout) {
1617 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1618 if (res)
1619 return res;
1620 p = &ts;
1621 }
1622 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1623}
1624
1625SYSCALL_DEFINE5(mq_timedreceive_time32, mqd_t, mqdes,
1626 char __user *, u_msg_ptr,
1627 unsigned int, msg_len, unsigned int __user *, u_msg_prio,
1628 const struct old_timespec32 __user *, u_abs_timeout)
1629{
1630 struct timespec64 ts, *p = NULL;
1631 if (u_abs_timeout) {
1632 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1633 if (res)
1634 return res;
1635 p = &ts;
1636 }
1637 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1638}
1639#endif
1640
1641static const struct inode_operations mqueue_dir_inode_operations = {
1642 .lookup = simple_lookup,
1643 .create = mqueue_create,
1644 .unlink = mqueue_unlink,
1645};
1646
1647static const struct file_operations mqueue_file_operations = {
1648 .flush = mqueue_flush_file,
1649 .poll = mqueue_poll_file,
1650 .read = mqueue_read_file,
1651 .llseek = default_llseek,
1652};
1653
1654static const struct super_operations mqueue_super_ops = {
1655 .alloc_inode = mqueue_alloc_inode,
1656 .free_inode = mqueue_free_inode,
1657 .evict_inode = mqueue_evict_inode,
1658 .statfs = simple_statfs,
1659};
1660
1661static const struct fs_context_operations mqueue_fs_context_ops = {
1662 .free = mqueue_fs_context_free,
1663 .get_tree = mqueue_get_tree,
1664};
1665
1666static struct file_system_type mqueue_fs_type = {
1667 .name = "mqueue",
1668 .init_fs_context = mqueue_init_fs_context,
1669 .kill_sb = kill_litter_super,
1670 .fs_flags = FS_USERNS_MOUNT,
1671};
1672
1673int mq_init_ns(struct ipc_namespace *ns)
1674{
1675 struct vfsmount *m;
1676
1677 ns->mq_queues_count = 0;
1678 ns->mq_queues_max = DFLT_QUEUESMAX;
1679 ns->mq_msg_max = DFLT_MSGMAX;
1680 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1681 ns->mq_msg_default = DFLT_MSG;
1682 ns->mq_msgsize_default = DFLT_MSGSIZE;
1683
1684 m = mq_create_mount(ns);
1685 if (IS_ERR(m))
1686 return PTR_ERR(m);
1687 ns->mq_mnt = m;
1688 return 0;
1689}
1690
1691void mq_clear_sbinfo(struct ipc_namespace *ns)
1692{
1693 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1694}
1695
1696void mq_put_mnt(struct ipc_namespace *ns)
1697{
1698 kern_unmount(ns->mq_mnt);
1699}
1700
1701static int __init init_mqueue_fs(void)
1702{
1703 int error;
1704
1705 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1706 sizeof(struct mqueue_inode_info), 0,
1707 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1708 if (mqueue_inode_cachep == NULL)
1709 return -ENOMEM;
1710
1711 /* ignore failures - they are not fatal */
1712 mq_sysctl_table = mq_register_sysctl_table();
1713
1714 error = register_filesystem(&mqueue_fs_type);
1715 if (error)
1716 goto out_sysctl;
1717
1718 spin_lock_init(&mq_lock);
1719
1720 error = mq_init_ns(&init_ipc_ns);
1721 if (error)
1722 goto out_filesystem;
1723
1724 return 0;
1725
1726out_filesystem:
1727 unregister_filesystem(&mqueue_fs_type);
1728out_sysctl:
1729 if (mq_sysctl_table)
1730 unregister_sysctl_table(mq_sysctl_table);
1731 kmem_cache_destroy(mqueue_inode_cachep);
1732 return error;
1733}
1734
1735device_initcall(init_mqueue_fs);