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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
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);