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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 bool newns; /* Set if newly created ipc namespace */
49};
50
51#define MQUEUE_MAGIC 0x19800202
52#define DIRENT_SIZE 20
53#define FILENT_SIZE 80
54
55#define SEND 0
56#define RECV 1
57
58#define STATE_NONE 0
59#define STATE_READY 1
60
61struct posix_msg_tree_node {
62 struct rb_node rb_node;
63 struct list_head msg_list;
64 int priority;
65};
66
67/*
68 * Locking:
69 *
70 * Accesses to a message queue are synchronized by acquiring info->lock.
71 *
72 * There are two notable exceptions:
73 * - The actual wakeup of a sleeping task is performed using the wake_q
74 * framework. info->lock is already released when wake_up_q is called.
75 * - The exit codepaths after sleeping check ext_wait_queue->state without
76 * any locks. If it is STATE_READY, then the syscall is completed without
77 * acquiring info->lock.
78 *
79 * MQ_BARRIER:
80 * To achieve proper release/acquire memory barrier pairing, the state is set to
81 * STATE_READY with smp_store_release(), and it is read with READ_ONCE followed
82 * by smp_acquire__after_ctrl_dep(). In addition, wake_q_add_safe() is used.
83 *
84 * This prevents the following races:
85 *
86 * 1) With the simple wake_q_add(), the task could be gone already before
87 * the increase of the reference happens
88 * Thread A
89 * Thread B
90 * WRITE_ONCE(wait.state, STATE_NONE);
91 * schedule_hrtimeout()
92 * wake_q_add(A)
93 * if (cmpxchg()) // success
94 * ->state = STATE_READY (reordered)
95 * <timeout returns>
96 * if (wait.state == STATE_READY) return;
97 * sysret to user space
98 * sys_exit()
99 * get_task_struct() // UaF
100 *
101 * Solution: Use wake_q_add_safe() and perform the get_task_struct() before
102 * the smp_store_release() that does ->state = STATE_READY.
103 *
104 * 2) Without proper _release/_acquire barriers, the woken up task
105 * could read stale data
106 *
107 * Thread A
108 * Thread B
109 * do_mq_timedreceive
110 * WRITE_ONCE(wait.state, STATE_NONE);
111 * schedule_hrtimeout()
112 * state = STATE_READY;
113 * <timeout returns>
114 * if (wait.state == STATE_READY) return;
115 * msg_ptr = wait.msg; // Access to stale data!
116 * receiver->msg = message; (reordered)
117 *
118 * Solution: use _release and _acquire barriers.
119 *
120 * 3) There is intentionally no barrier when setting current->state
121 * to TASK_INTERRUPTIBLE: spin_unlock(&info->lock) provides the
122 * release memory barrier, and the wakeup is triggered when holding
123 * info->lock, i.e. spin_lock(&info->lock) provided a pairing
124 * acquire memory barrier.
125 */
126
127struct ext_wait_queue { /* queue of sleeping tasks */
128 struct task_struct *task;
129 struct list_head list;
130 struct msg_msg *msg; /* ptr of loaded message */
131 int state; /* one of STATE_* values */
132};
133
134struct mqueue_inode_info {
135 spinlock_t lock;
136 struct inode vfs_inode;
137 wait_queue_head_t wait_q;
138
139 struct rb_root msg_tree;
140 struct rb_node *msg_tree_rightmost;
141 struct posix_msg_tree_node *node_cache;
142 struct mq_attr attr;
143
144 struct sigevent notify;
145 struct pid *notify_owner;
146 u32 notify_self_exec_id;
147 struct user_namespace *notify_user_ns;
148 struct ucounts *ucounts; /* user who created, for accounting */
149 struct sock *notify_sock;
150 struct sk_buff *notify_cookie;
151
152 /* for tasks waiting for free space and messages, respectively */
153 struct ext_wait_queue e_wait_q[2];
154
155 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
156};
157
158static struct file_system_type mqueue_fs_type;
159static const struct inode_operations mqueue_dir_inode_operations;
160static const struct file_operations mqueue_file_operations;
161static const struct super_operations mqueue_super_ops;
162static const struct fs_context_operations mqueue_fs_context_ops;
163static void remove_notification(struct mqueue_inode_info *info);
164
165static struct kmem_cache *mqueue_inode_cachep;
166
167static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
168{
169 return container_of(inode, struct mqueue_inode_info, vfs_inode);
170}
171
172/*
173 * This routine should be called with the mq_lock held.
174 */
175static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
176{
177 return get_ipc_ns(inode->i_sb->s_fs_info);
178}
179
180static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
181{
182 struct ipc_namespace *ns;
183
184 spin_lock(&mq_lock);
185 ns = __get_ns_from_inode(inode);
186 spin_unlock(&mq_lock);
187 return ns;
188}
189
190/* Auxiliary functions to manipulate messages' list */
191static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
192{
193 struct rb_node **p, *parent = NULL;
194 struct posix_msg_tree_node *leaf;
195 bool rightmost = true;
196
197 p = &info->msg_tree.rb_node;
198 while (*p) {
199 parent = *p;
200 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
201
202 if (likely(leaf->priority == msg->m_type))
203 goto insert_msg;
204 else if (msg->m_type < leaf->priority) {
205 p = &(*p)->rb_left;
206 rightmost = false;
207 } else
208 p = &(*p)->rb_right;
209 }
210 if (info->node_cache) {
211 leaf = info->node_cache;
212 info->node_cache = NULL;
213 } else {
214 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
215 if (!leaf)
216 return -ENOMEM;
217 INIT_LIST_HEAD(&leaf->msg_list);
218 }
219 leaf->priority = msg->m_type;
220
221 if (rightmost)
222 info->msg_tree_rightmost = &leaf->rb_node;
223
224 rb_link_node(&leaf->rb_node, parent, p);
225 rb_insert_color(&leaf->rb_node, &info->msg_tree);
226insert_msg:
227 info->attr.mq_curmsgs++;
228 info->qsize += msg->m_ts;
229 list_add_tail(&msg->m_list, &leaf->msg_list);
230 return 0;
231}
232
233static inline void msg_tree_erase(struct posix_msg_tree_node *leaf,
234 struct mqueue_inode_info *info)
235{
236 struct rb_node *node = &leaf->rb_node;
237
238 if (info->msg_tree_rightmost == node)
239 info->msg_tree_rightmost = rb_prev(node);
240
241 rb_erase(node, &info->msg_tree);
242 if (info->node_cache)
243 kfree(leaf);
244 else
245 info->node_cache = leaf;
246}
247
248static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
249{
250 struct rb_node *parent = NULL;
251 struct posix_msg_tree_node *leaf;
252 struct msg_msg *msg;
253
254try_again:
255 /*
256 * During insert, low priorities go to the left and high to the
257 * right. On receive, we want the highest priorities first, so
258 * walk all the way to the right.
259 */
260 parent = info->msg_tree_rightmost;
261 if (!parent) {
262 if (info->attr.mq_curmsgs) {
263 pr_warn_once("Inconsistency in POSIX message queue, "
264 "no tree element, but supposedly messages "
265 "should exist!\n");
266 info->attr.mq_curmsgs = 0;
267 }
268 return NULL;
269 }
270 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
271 if (unlikely(list_empty(&leaf->msg_list))) {
272 pr_warn_once("Inconsistency in POSIX message queue, "
273 "empty leaf node but we haven't implemented "
274 "lazy leaf delete!\n");
275 msg_tree_erase(leaf, info);
276 goto try_again;
277 } else {
278 msg = list_first_entry(&leaf->msg_list,
279 struct msg_msg, m_list);
280 list_del(&msg->m_list);
281 if (list_empty(&leaf->msg_list)) {
282 msg_tree_erase(leaf, info);
283 }
284 }
285 info->attr.mq_curmsgs--;
286 info->qsize -= msg->m_ts;
287 return msg;
288}
289
290static struct inode *mqueue_get_inode(struct super_block *sb,
291 struct ipc_namespace *ipc_ns, umode_t mode,
292 struct mq_attr *attr)
293{
294 struct inode *inode;
295 int ret = -ENOMEM;
296
297 inode = new_inode(sb);
298 if (!inode)
299 goto err;
300
301 inode->i_ino = get_next_ino();
302 inode->i_mode = mode;
303 inode->i_uid = current_fsuid();
304 inode->i_gid = current_fsgid();
305 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
306
307 if (S_ISREG(mode)) {
308 struct mqueue_inode_info *info;
309 unsigned long mq_bytes, mq_treesize;
310
311 inode->i_fop = &mqueue_file_operations;
312 inode->i_size = FILENT_SIZE;
313 /* mqueue specific info */
314 info = MQUEUE_I(inode);
315 spin_lock_init(&info->lock);
316 init_waitqueue_head(&info->wait_q);
317 INIT_LIST_HEAD(&info->e_wait_q[0].list);
318 INIT_LIST_HEAD(&info->e_wait_q[1].list);
319 info->notify_owner = NULL;
320 info->notify_user_ns = NULL;
321 info->qsize = 0;
322 info->ucounts = NULL; /* set when all is ok */
323 info->msg_tree = RB_ROOT;
324 info->msg_tree_rightmost = NULL;
325 info->node_cache = NULL;
326 memset(&info->attr, 0, sizeof(info->attr));
327 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
328 ipc_ns->mq_msg_default);
329 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
330 ipc_ns->mq_msgsize_default);
331 if (attr) {
332 info->attr.mq_maxmsg = attr->mq_maxmsg;
333 info->attr.mq_msgsize = attr->mq_msgsize;
334 }
335 /*
336 * We used to allocate a static array of pointers and account
337 * the size of that array as well as one msg_msg struct per
338 * possible message into the queue size. That's no longer
339 * accurate as the queue is now an rbtree and will grow and
340 * shrink depending on usage patterns. We can, however, still
341 * account one msg_msg struct per message, but the nodes are
342 * allocated depending on priority usage, and most programs
343 * only use one, or a handful, of priorities. However, since
344 * this is pinned memory, we need to assume worst case, so
345 * that means the min(mq_maxmsg, max_priorities) * struct
346 * posix_msg_tree_node.
347 */
348
349 ret = -EINVAL;
350 if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
351 goto out_inode;
352 if (capable(CAP_SYS_RESOURCE)) {
353 if (info->attr.mq_maxmsg > HARD_MSGMAX ||
354 info->attr.mq_msgsize > HARD_MSGSIZEMAX)
355 goto out_inode;
356 } else {
357 if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
358 info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
359 goto out_inode;
360 }
361 ret = -EOVERFLOW;
362 /* check for overflow */
363 if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
364 goto out_inode;
365 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
366 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
367 sizeof(struct posix_msg_tree_node);
368 mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
369 if (mq_bytes + mq_treesize < mq_bytes)
370 goto out_inode;
371 mq_bytes += mq_treesize;
372 info->ucounts = get_ucounts(current_ucounts());
373 if (info->ucounts) {
374 long msgqueue;
375
376 spin_lock(&mq_lock);
377 msgqueue = inc_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
378 if (msgqueue == LONG_MAX || msgqueue > rlimit(RLIMIT_MSGQUEUE)) {
379 dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
380 spin_unlock(&mq_lock);
381 put_ucounts(info->ucounts);
382 info->ucounts = NULL;
383 /* mqueue_evict_inode() releases info->messages */
384 ret = -EMFILE;
385 goto out_inode;
386 }
387 spin_unlock(&mq_lock);
388 }
389 } else if (S_ISDIR(mode)) {
390 inc_nlink(inode);
391 /* Some things misbehave if size == 0 on a directory */
392 inode->i_size = 2 * DIRENT_SIZE;
393 inode->i_op = &mqueue_dir_inode_operations;
394 inode->i_fop = &simple_dir_operations;
395 }
396
397 return inode;
398out_inode:
399 iput(inode);
400err:
401 return ERR_PTR(ret);
402}
403
404static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc)
405{
406 struct inode *inode;
407 struct ipc_namespace *ns = sb->s_fs_info;
408
409 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
410 sb->s_blocksize = PAGE_SIZE;
411 sb->s_blocksize_bits = PAGE_SHIFT;
412 sb->s_magic = MQUEUE_MAGIC;
413 sb->s_op = &mqueue_super_ops;
414
415 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
416 if (IS_ERR(inode))
417 return PTR_ERR(inode);
418
419 sb->s_root = d_make_root(inode);
420 if (!sb->s_root)
421 return -ENOMEM;
422 return 0;
423}
424
425static int mqueue_get_tree(struct fs_context *fc)
426{
427 struct mqueue_fs_context *ctx = fc->fs_private;
428
429 /*
430 * With a newly created ipc namespace, we don't need to do a search
431 * for an ipc namespace match, but we still need to set s_fs_info.
432 */
433 if (ctx->newns) {
434 fc->s_fs_info = ctx->ipc_ns;
435 return get_tree_nodev(fc, mqueue_fill_super);
436 }
437 return get_tree_keyed(fc, mqueue_fill_super, ctx->ipc_ns);
438}
439
440static void mqueue_fs_context_free(struct fs_context *fc)
441{
442 struct mqueue_fs_context *ctx = fc->fs_private;
443
444 put_ipc_ns(ctx->ipc_ns);
445 kfree(ctx);
446}
447
448static int mqueue_init_fs_context(struct fs_context *fc)
449{
450 struct mqueue_fs_context *ctx;
451
452 ctx = kzalloc(sizeof(struct mqueue_fs_context), GFP_KERNEL);
453 if (!ctx)
454 return -ENOMEM;
455
456 ctx->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
457 put_user_ns(fc->user_ns);
458 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
459 fc->fs_private = ctx;
460 fc->ops = &mqueue_fs_context_ops;
461 return 0;
462}
463
464/*
465 * mq_init_ns() is currently the only caller of mq_create_mount().
466 * So the ns parameter is always a newly created ipc namespace.
467 */
468static struct vfsmount *mq_create_mount(struct ipc_namespace *ns)
469{
470 struct mqueue_fs_context *ctx;
471 struct fs_context *fc;
472 struct vfsmount *mnt;
473
474 fc = fs_context_for_mount(&mqueue_fs_type, SB_KERNMOUNT);
475 if (IS_ERR(fc))
476 return ERR_CAST(fc);
477
478 ctx = fc->fs_private;
479 ctx->newns = true;
480 put_ipc_ns(ctx->ipc_ns);
481 ctx->ipc_ns = get_ipc_ns(ns);
482 put_user_ns(fc->user_ns);
483 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
484
485 mnt = fc_mount(fc);
486 put_fs_context(fc);
487 return mnt;
488}
489
490static void init_once(void *foo)
491{
492 struct mqueue_inode_info *p = foo;
493
494 inode_init_once(&p->vfs_inode);
495}
496
497static struct inode *mqueue_alloc_inode(struct super_block *sb)
498{
499 struct mqueue_inode_info *ei;
500
501 ei = alloc_inode_sb(sb, mqueue_inode_cachep, GFP_KERNEL);
502 if (!ei)
503 return NULL;
504 return &ei->vfs_inode;
505}
506
507static void mqueue_free_inode(struct inode *inode)
508{
509 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
510}
511
512static void mqueue_evict_inode(struct inode *inode)
513{
514 struct mqueue_inode_info *info;
515 struct ipc_namespace *ipc_ns;
516 struct msg_msg *msg, *nmsg;
517 LIST_HEAD(tmp_msg);
518
519 clear_inode(inode);
520
521 if (S_ISDIR(inode->i_mode))
522 return;
523
524 ipc_ns = get_ns_from_inode(inode);
525 info = MQUEUE_I(inode);
526 spin_lock(&info->lock);
527 while ((msg = msg_get(info)) != NULL)
528 list_add_tail(&msg->m_list, &tmp_msg);
529 kfree(info->node_cache);
530 spin_unlock(&info->lock);
531
532 list_for_each_entry_safe(msg, nmsg, &tmp_msg, m_list) {
533 list_del(&msg->m_list);
534 free_msg(msg);
535 }
536
537 if (info->ucounts) {
538 unsigned long mq_bytes, mq_treesize;
539
540 /* Total amount of bytes accounted for the mqueue */
541 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
542 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
543 sizeof(struct posix_msg_tree_node);
544
545 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
546 info->attr.mq_msgsize);
547
548 spin_lock(&mq_lock);
549 dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
550 /*
551 * get_ns_from_inode() ensures that the
552 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
553 * to which we now hold a reference, or it is NULL.
554 * We can't put it here under mq_lock, though.
555 */
556 if (ipc_ns)
557 ipc_ns->mq_queues_count--;
558 spin_unlock(&mq_lock);
559 put_ucounts(info->ucounts);
560 info->ucounts = NULL;
561 }
562 if (ipc_ns)
563 put_ipc_ns(ipc_ns);
564}
565
566static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
567{
568 struct inode *dir = dentry->d_parent->d_inode;
569 struct inode *inode;
570 struct mq_attr *attr = arg;
571 int error;
572 struct ipc_namespace *ipc_ns;
573
574 spin_lock(&mq_lock);
575 ipc_ns = __get_ns_from_inode(dir);
576 if (!ipc_ns) {
577 error = -EACCES;
578 goto out_unlock;
579 }
580
581 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
582 !capable(CAP_SYS_RESOURCE)) {
583 error = -ENOSPC;
584 goto out_unlock;
585 }
586 ipc_ns->mq_queues_count++;
587 spin_unlock(&mq_lock);
588
589 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
590 if (IS_ERR(inode)) {
591 error = PTR_ERR(inode);
592 spin_lock(&mq_lock);
593 ipc_ns->mq_queues_count--;
594 goto out_unlock;
595 }
596
597 put_ipc_ns(ipc_ns);
598 dir->i_size += DIRENT_SIZE;
599 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
600
601 d_instantiate(dentry, inode);
602 dget(dentry);
603 return 0;
604out_unlock:
605 spin_unlock(&mq_lock);
606 if (ipc_ns)
607 put_ipc_ns(ipc_ns);
608 return error;
609}
610
611static int mqueue_create(struct user_namespace *mnt_userns, struct inode *dir,
612 struct dentry *dentry, umode_t mode, bool excl)
613{
614 return mqueue_create_attr(dentry, mode, NULL);
615}
616
617static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
618{
619 struct inode *inode = d_inode(dentry);
620
621 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
622 dir->i_size -= DIRENT_SIZE;
623 drop_nlink(inode);
624 dput(dentry);
625 return 0;
626}
627
628/*
629* This is routine for system read from queue file.
630* To avoid mess with doing here some sort of mq_receive we allow
631* to read only queue size & notification info (the only values
632* that are interesting from user point of view and aren't accessible
633* through std routines)
634*/
635static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
636 size_t count, loff_t *off)
637{
638 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
639 char buffer[FILENT_SIZE];
640 ssize_t ret;
641
642 spin_lock(&info->lock);
643 snprintf(buffer, sizeof(buffer),
644 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
645 info->qsize,
646 info->notify_owner ? info->notify.sigev_notify : 0,
647 (info->notify_owner &&
648 info->notify.sigev_notify == SIGEV_SIGNAL) ?
649 info->notify.sigev_signo : 0,
650 pid_vnr(info->notify_owner));
651 spin_unlock(&info->lock);
652 buffer[sizeof(buffer)-1] = '\0';
653
654 ret = simple_read_from_buffer(u_data, count, off, buffer,
655 strlen(buffer));
656 if (ret <= 0)
657 return ret;
658
659 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
660 return ret;
661}
662
663static int mqueue_flush_file(struct file *filp, fl_owner_t id)
664{
665 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
666
667 spin_lock(&info->lock);
668 if (task_tgid(current) == info->notify_owner)
669 remove_notification(info);
670
671 spin_unlock(&info->lock);
672 return 0;
673}
674
675static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
676{
677 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
678 __poll_t retval = 0;
679
680 poll_wait(filp, &info->wait_q, poll_tab);
681
682 spin_lock(&info->lock);
683 if (info->attr.mq_curmsgs)
684 retval = EPOLLIN | EPOLLRDNORM;
685
686 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
687 retval |= EPOLLOUT | EPOLLWRNORM;
688 spin_unlock(&info->lock);
689
690 return retval;
691}
692
693/* Adds current to info->e_wait_q[sr] before element with smaller prio */
694static void wq_add(struct mqueue_inode_info *info, int sr,
695 struct ext_wait_queue *ewp)
696{
697 struct ext_wait_queue *walk;
698
699 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
700 if (walk->task->prio <= current->prio) {
701 list_add_tail(&ewp->list, &walk->list);
702 return;
703 }
704 }
705 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
706}
707
708/*
709 * Puts current task to sleep. Caller must hold queue lock. After return
710 * lock isn't held.
711 * sr: SEND or RECV
712 */
713static int wq_sleep(struct mqueue_inode_info *info, int sr,
714 ktime_t *timeout, struct ext_wait_queue *ewp)
715 __releases(&info->lock)
716{
717 int retval;
718 signed long time;
719
720 wq_add(info, sr, ewp);
721
722 for (;;) {
723 /* memory barrier not required, we hold info->lock */
724 __set_current_state(TASK_INTERRUPTIBLE);
725
726 spin_unlock(&info->lock);
727 time = schedule_hrtimeout_range_clock(timeout, 0,
728 HRTIMER_MODE_ABS, CLOCK_REALTIME);
729
730 if (READ_ONCE(ewp->state) == STATE_READY) {
731 /* see MQ_BARRIER for purpose/pairing */
732 smp_acquire__after_ctrl_dep();
733 retval = 0;
734 goto out;
735 }
736 spin_lock(&info->lock);
737
738 /* we hold info->lock, so no memory barrier required */
739 if (READ_ONCE(ewp->state) == STATE_READY) {
740 retval = 0;
741 goto out_unlock;
742 }
743 if (signal_pending(current)) {
744 retval = -ERESTARTSYS;
745 break;
746 }
747 if (time == 0) {
748 retval = -ETIMEDOUT;
749 break;
750 }
751 }
752 list_del(&ewp->list);
753out_unlock:
754 spin_unlock(&info->lock);
755out:
756 return retval;
757}
758
759/*
760 * Returns waiting task that should be serviced first or NULL if none exists
761 */
762static struct ext_wait_queue *wq_get_first_waiter(
763 struct mqueue_inode_info *info, int sr)
764{
765 struct list_head *ptr;
766
767 ptr = info->e_wait_q[sr].list.prev;
768 if (ptr == &info->e_wait_q[sr].list)
769 return NULL;
770 return list_entry(ptr, struct ext_wait_queue, list);
771}
772
773
774static inline void set_cookie(struct sk_buff *skb, char code)
775{
776 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
777}
778
779/*
780 * The next function is only to split too long sys_mq_timedsend
781 */
782static void __do_notify(struct mqueue_inode_info *info)
783{
784 /* notification
785 * invoked when there is registered process and there isn't process
786 * waiting synchronously for message AND state of queue changed from
787 * empty to not empty. Here we are sure that no one is waiting
788 * synchronously. */
789 if (info->notify_owner &&
790 info->attr.mq_curmsgs == 1) {
791 switch (info->notify.sigev_notify) {
792 case SIGEV_NONE:
793 break;
794 case SIGEV_SIGNAL: {
795 struct kernel_siginfo sig_i;
796 struct task_struct *task;
797
798 /* do_mq_notify() accepts sigev_signo == 0, why?? */
799 if (!info->notify.sigev_signo)
800 break;
801
802 clear_siginfo(&sig_i);
803 sig_i.si_signo = info->notify.sigev_signo;
804 sig_i.si_errno = 0;
805 sig_i.si_code = SI_MESGQ;
806 sig_i.si_value = info->notify.sigev_value;
807 rcu_read_lock();
808 /* map current pid/uid into info->owner's namespaces */
809 sig_i.si_pid = task_tgid_nr_ns(current,
810 ns_of_pid(info->notify_owner));
811 sig_i.si_uid = from_kuid_munged(info->notify_user_ns,
812 current_uid());
813 /*
814 * We can't use kill_pid_info(), this signal should
815 * bypass check_kill_permission(). It is from kernel
816 * but si_fromuser() can't know this.
817 * We do check the self_exec_id, to avoid sending
818 * signals to programs that don't expect them.
819 */
820 task = pid_task(info->notify_owner, PIDTYPE_TGID);
821 if (task && task->self_exec_id ==
822 info->notify_self_exec_id) {
823 do_send_sig_info(info->notify.sigev_signo,
824 &sig_i, task, PIDTYPE_TGID);
825 }
826 rcu_read_unlock();
827 break;
828 }
829 case SIGEV_THREAD:
830 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
831 netlink_sendskb(info->notify_sock, info->notify_cookie);
832 break;
833 }
834 /* after notification unregisters process */
835 put_pid(info->notify_owner);
836 put_user_ns(info->notify_user_ns);
837 info->notify_owner = NULL;
838 info->notify_user_ns = NULL;
839 }
840 wake_up(&info->wait_q);
841}
842
843static int prepare_timeout(const struct __kernel_timespec __user *u_abs_timeout,
844 struct timespec64 *ts)
845{
846 if (get_timespec64(ts, u_abs_timeout))
847 return -EFAULT;
848 if (!timespec64_valid(ts))
849 return -EINVAL;
850 return 0;
851}
852
853static void remove_notification(struct mqueue_inode_info *info)
854{
855 if (info->notify_owner != NULL &&
856 info->notify.sigev_notify == SIGEV_THREAD) {
857 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
858 netlink_sendskb(info->notify_sock, info->notify_cookie);
859 }
860 put_pid(info->notify_owner);
861 put_user_ns(info->notify_user_ns);
862 info->notify_owner = NULL;
863 info->notify_user_ns = NULL;
864}
865
866static int prepare_open(struct dentry *dentry, int oflag, int ro,
867 umode_t mode, struct filename *name,
868 struct mq_attr *attr)
869{
870 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
871 MAY_READ | MAY_WRITE };
872 int acc;
873
874 if (d_really_is_negative(dentry)) {
875 if (!(oflag & O_CREAT))
876 return -ENOENT;
877 if (ro)
878 return ro;
879 audit_inode_parent_hidden(name, dentry->d_parent);
880 return vfs_mkobj(dentry, mode & ~current_umask(),
881 mqueue_create_attr, attr);
882 }
883 /* it already existed */
884 audit_inode(name, dentry, 0);
885 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
886 return -EEXIST;
887 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
888 return -EINVAL;
889 acc = oflag2acc[oflag & O_ACCMODE];
890 return inode_permission(&init_user_ns, d_inode(dentry), acc);
891}
892
893static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
894 struct mq_attr *attr)
895{
896 struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
897 struct dentry *root = mnt->mnt_root;
898 struct filename *name;
899 struct path path;
900 int fd, error;
901 int ro;
902
903 audit_mq_open(oflag, mode, attr);
904
905 if (IS_ERR(name = getname(u_name)))
906 return PTR_ERR(name);
907
908 fd = get_unused_fd_flags(O_CLOEXEC);
909 if (fd < 0)
910 goto out_putname;
911
912 ro = mnt_want_write(mnt); /* we'll drop it in any case */
913 inode_lock(d_inode(root));
914 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
915 if (IS_ERR(path.dentry)) {
916 error = PTR_ERR(path.dentry);
917 goto out_putfd;
918 }
919 path.mnt = mntget(mnt);
920 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
921 if (!error) {
922 struct file *file = dentry_open(&path, oflag, current_cred());
923 if (!IS_ERR(file))
924 fd_install(fd, file);
925 else
926 error = PTR_ERR(file);
927 }
928 path_put(&path);
929out_putfd:
930 if (error) {
931 put_unused_fd(fd);
932 fd = error;
933 }
934 inode_unlock(d_inode(root));
935 if (!ro)
936 mnt_drop_write(mnt);
937out_putname:
938 putname(name);
939 return fd;
940}
941
942SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
943 struct mq_attr __user *, u_attr)
944{
945 struct mq_attr attr;
946 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
947 return -EFAULT;
948
949 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
950}
951
952SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
953{
954 int err;
955 struct filename *name;
956 struct dentry *dentry;
957 struct inode *inode = NULL;
958 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
959 struct vfsmount *mnt = ipc_ns->mq_mnt;
960
961 name = getname(u_name);
962 if (IS_ERR(name))
963 return PTR_ERR(name);
964
965 audit_inode_parent_hidden(name, mnt->mnt_root);
966 err = mnt_want_write(mnt);
967 if (err)
968 goto out_name;
969 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
970 dentry = lookup_one_len(name->name, mnt->mnt_root,
971 strlen(name->name));
972 if (IS_ERR(dentry)) {
973 err = PTR_ERR(dentry);
974 goto out_unlock;
975 }
976
977 inode = d_inode(dentry);
978 if (!inode) {
979 err = -ENOENT;
980 } else {
981 ihold(inode);
982 err = vfs_unlink(&init_user_ns, d_inode(dentry->d_parent),
983 dentry, NULL);
984 }
985 dput(dentry);
986
987out_unlock:
988 inode_unlock(d_inode(mnt->mnt_root));
989 iput(inode);
990 mnt_drop_write(mnt);
991out_name:
992 putname(name);
993
994 return err;
995}
996
997/* Pipelined send and receive functions.
998 *
999 * If a receiver finds no waiting message, then it registers itself in the
1000 * list of waiting receivers. A sender checks that list before adding the new
1001 * message into the message array. If there is a waiting receiver, then it
1002 * bypasses the message array and directly hands the message over to the
1003 * receiver. The receiver accepts the message and returns without grabbing the
1004 * queue spinlock:
1005 *
1006 * - Set pointer to message.
1007 * - Queue the receiver task for later wakeup (without the info->lock).
1008 * - Update its state to STATE_READY. Now the receiver can continue.
1009 * - Wake up the process after the lock is dropped. Should the process wake up
1010 * before this wakeup (due to a timeout or a signal) it will either see
1011 * STATE_READY and continue or acquire the lock to check the state again.
1012 *
1013 * The same algorithm is used for senders.
1014 */
1015
1016static inline void __pipelined_op(struct wake_q_head *wake_q,
1017 struct mqueue_inode_info *info,
1018 struct ext_wait_queue *this)
1019{
1020 struct task_struct *task;
1021
1022 list_del(&this->list);
1023 task = get_task_struct(this->task);
1024
1025 /* see MQ_BARRIER for purpose/pairing */
1026 smp_store_release(&this->state, STATE_READY);
1027 wake_q_add_safe(wake_q, task);
1028}
1029
1030/* pipelined_send() - send a message directly to the task waiting in
1031 * sys_mq_timedreceive() (without inserting message into a queue).
1032 */
1033static inline void pipelined_send(struct wake_q_head *wake_q,
1034 struct mqueue_inode_info *info,
1035 struct msg_msg *message,
1036 struct ext_wait_queue *receiver)
1037{
1038 receiver->msg = message;
1039 __pipelined_op(wake_q, info, receiver);
1040}
1041
1042/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
1043 * gets its message and put to the queue (we have one free place for sure). */
1044static inline void pipelined_receive(struct wake_q_head *wake_q,
1045 struct mqueue_inode_info *info)
1046{
1047 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
1048
1049 if (!sender) {
1050 /* for poll */
1051 wake_up_interruptible(&info->wait_q);
1052 return;
1053 }
1054 if (msg_insert(sender->msg, info))
1055 return;
1056
1057 __pipelined_op(wake_q, info, sender);
1058}
1059
1060static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
1061 size_t msg_len, unsigned int msg_prio,
1062 struct timespec64 *ts)
1063{
1064 struct fd f;
1065 struct inode *inode;
1066 struct ext_wait_queue wait;
1067 struct ext_wait_queue *receiver;
1068 struct msg_msg *msg_ptr;
1069 struct mqueue_inode_info *info;
1070 ktime_t expires, *timeout = NULL;
1071 struct posix_msg_tree_node *new_leaf = NULL;
1072 int ret = 0;
1073 DEFINE_WAKE_Q(wake_q);
1074
1075 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
1076 return -EINVAL;
1077
1078 if (ts) {
1079 expires = timespec64_to_ktime(*ts);
1080 timeout = &expires;
1081 }
1082
1083 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
1084
1085 f = fdget(mqdes);
1086 if (unlikely(!f.file)) {
1087 ret = -EBADF;
1088 goto out;
1089 }
1090
1091 inode = file_inode(f.file);
1092 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1093 ret = -EBADF;
1094 goto out_fput;
1095 }
1096 info = MQUEUE_I(inode);
1097 audit_file(f.file);
1098
1099 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
1100 ret = -EBADF;
1101 goto out_fput;
1102 }
1103
1104 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1105 ret = -EMSGSIZE;
1106 goto out_fput;
1107 }
1108
1109 /* First try to allocate memory, before doing anything with
1110 * existing queues. */
1111 msg_ptr = load_msg(u_msg_ptr, msg_len);
1112 if (IS_ERR(msg_ptr)) {
1113 ret = PTR_ERR(msg_ptr);
1114 goto out_fput;
1115 }
1116 msg_ptr->m_ts = msg_len;
1117 msg_ptr->m_type = msg_prio;
1118
1119 /*
1120 * msg_insert really wants us to have a valid, spare node struct so
1121 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1122 * fall back to that if necessary.
1123 */
1124 if (!info->node_cache)
1125 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1126
1127 spin_lock(&info->lock);
1128
1129 if (!info->node_cache && new_leaf) {
1130 /* Save our speculative allocation into the cache */
1131 INIT_LIST_HEAD(&new_leaf->msg_list);
1132 info->node_cache = new_leaf;
1133 new_leaf = NULL;
1134 } else {
1135 kfree(new_leaf);
1136 }
1137
1138 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1139 if (f.file->f_flags & O_NONBLOCK) {
1140 ret = -EAGAIN;
1141 } else {
1142 wait.task = current;
1143 wait.msg = (void *) msg_ptr;
1144
1145 /* memory barrier not required, we hold info->lock */
1146 WRITE_ONCE(wait.state, STATE_NONE);
1147 ret = wq_sleep(info, SEND, timeout, &wait);
1148 /*
1149 * wq_sleep must be called with info->lock held, and
1150 * returns with the lock released
1151 */
1152 goto out_free;
1153 }
1154 } else {
1155 receiver = wq_get_first_waiter(info, RECV);
1156 if (receiver) {
1157 pipelined_send(&wake_q, info, msg_ptr, receiver);
1158 } else {
1159 /* adds message to the queue */
1160 ret = msg_insert(msg_ptr, info);
1161 if (ret)
1162 goto out_unlock;
1163 __do_notify(info);
1164 }
1165 inode->i_atime = inode->i_mtime = inode->i_ctime =
1166 current_time(inode);
1167 }
1168out_unlock:
1169 spin_unlock(&info->lock);
1170 wake_up_q(&wake_q);
1171out_free:
1172 if (ret)
1173 free_msg(msg_ptr);
1174out_fput:
1175 fdput(f);
1176out:
1177 return ret;
1178}
1179
1180static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1181 size_t msg_len, unsigned int __user *u_msg_prio,
1182 struct timespec64 *ts)
1183{
1184 ssize_t ret;
1185 struct msg_msg *msg_ptr;
1186 struct fd f;
1187 struct inode *inode;
1188 struct mqueue_inode_info *info;
1189 struct ext_wait_queue wait;
1190 ktime_t expires, *timeout = NULL;
1191 struct posix_msg_tree_node *new_leaf = NULL;
1192
1193 if (ts) {
1194 expires = timespec64_to_ktime(*ts);
1195 timeout = &expires;
1196 }
1197
1198 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1199
1200 f = fdget(mqdes);
1201 if (unlikely(!f.file)) {
1202 ret = -EBADF;
1203 goto out;
1204 }
1205
1206 inode = file_inode(f.file);
1207 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1208 ret = -EBADF;
1209 goto out_fput;
1210 }
1211 info = MQUEUE_I(inode);
1212 audit_file(f.file);
1213
1214 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1215 ret = -EBADF;
1216 goto out_fput;
1217 }
1218
1219 /* checks if buffer is big enough */
1220 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1221 ret = -EMSGSIZE;
1222 goto out_fput;
1223 }
1224
1225 /*
1226 * msg_insert really wants us to have a valid, spare node struct so
1227 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1228 * fall back to that if necessary.
1229 */
1230 if (!info->node_cache)
1231 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1232
1233 spin_lock(&info->lock);
1234
1235 if (!info->node_cache && new_leaf) {
1236 /* Save our speculative allocation into the cache */
1237 INIT_LIST_HEAD(&new_leaf->msg_list);
1238 info->node_cache = new_leaf;
1239 } else {
1240 kfree(new_leaf);
1241 }
1242
1243 if (info->attr.mq_curmsgs == 0) {
1244 if (f.file->f_flags & O_NONBLOCK) {
1245 spin_unlock(&info->lock);
1246 ret = -EAGAIN;
1247 } else {
1248 wait.task = current;
1249
1250 /* memory barrier not required, we hold info->lock */
1251 WRITE_ONCE(wait.state, STATE_NONE);
1252 ret = wq_sleep(info, RECV, timeout, &wait);
1253 msg_ptr = wait.msg;
1254 }
1255 } else {
1256 DEFINE_WAKE_Q(wake_q);
1257
1258 msg_ptr = msg_get(info);
1259
1260 inode->i_atime = inode->i_mtime = inode->i_ctime =
1261 current_time(inode);
1262
1263 /* There is now free space in queue. */
1264 pipelined_receive(&wake_q, info);
1265 spin_unlock(&info->lock);
1266 wake_up_q(&wake_q);
1267 ret = 0;
1268 }
1269 if (ret == 0) {
1270 ret = msg_ptr->m_ts;
1271
1272 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1273 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1274 ret = -EFAULT;
1275 }
1276 free_msg(msg_ptr);
1277 }
1278out_fput:
1279 fdput(f);
1280out:
1281 return ret;
1282}
1283
1284SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1285 size_t, msg_len, unsigned int, msg_prio,
1286 const struct __kernel_timespec __user *, u_abs_timeout)
1287{
1288 struct timespec64 ts, *p = NULL;
1289 if (u_abs_timeout) {
1290 int res = prepare_timeout(u_abs_timeout, &ts);
1291 if (res)
1292 return res;
1293 p = &ts;
1294 }
1295 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1296}
1297
1298SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1299 size_t, msg_len, unsigned int __user *, u_msg_prio,
1300 const struct __kernel_timespec __user *, u_abs_timeout)
1301{
1302 struct timespec64 ts, *p = NULL;
1303 if (u_abs_timeout) {
1304 int res = prepare_timeout(u_abs_timeout, &ts);
1305 if (res)
1306 return res;
1307 p = &ts;
1308 }
1309 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1310}
1311
1312/*
1313 * Notes: the case when user wants us to deregister (with NULL as pointer)
1314 * and he isn't currently owner of notification, will be silently discarded.
1315 * It isn't explicitly defined in the POSIX.
1316 */
1317static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1318{
1319 int ret;
1320 struct fd f;
1321 struct sock *sock;
1322 struct inode *inode;
1323 struct mqueue_inode_info *info;
1324 struct sk_buff *nc;
1325
1326 audit_mq_notify(mqdes, notification);
1327
1328 nc = NULL;
1329 sock = NULL;
1330 if (notification != NULL) {
1331 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1332 notification->sigev_notify != SIGEV_SIGNAL &&
1333 notification->sigev_notify != SIGEV_THREAD))
1334 return -EINVAL;
1335 if (notification->sigev_notify == SIGEV_SIGNAL &&
1336 !valid_signal(notification->sigev_signo)) {
1337 return -EINVAL;
1338 }
1339 if (notification->sigev_notify == SIGEV_THREAD) {
1340 long timeo;
1341
1342 /* create the notify skb */
1343 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1344 if (!nc)
1345 return -ENOMEM;
1346
1347 if (copy_from_user(nc->data,
1348 notification->sigev_value.sival_ptr,
1349 NOTIFY_COOKIE_LEN)) {
1350 ret = -EFAULT;
1351 goto free_skb;
1352 }
1353
1354 /* TODO: add a header? */
1355 skb_put(nc, NOTIFY_COOKIE_LEN);
1356 /* and attach it to the socket */
1357retry:
1358 f = fdget(notification->sigev_signo);
1359 if (!f.file) {
1360 ret = -EBADF;
1361 goto out;
1362 }
1363 sock = netlink_getsockbyfilp(f.file);
1364 fdput(f);
1365 if (IS_ERR(sock)) {
1366 ret = PTR_ERR(sock);
1367 goto free_skb;
1368 }
1369
1370 timeo = MAX_SCHEDULE_TIMEOUT;
1371 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1372 if (ret == 1) {
1373 sock = NULL;
1374 goto retry;
1375 }
1376 if (ret)
1377 return ret;
1378 }
1379 }
1380
1381 f = fdget(mqdes);
1382 if (!f.file) {
1383 ret = -EBADF;
1384 goto out;
1385 }
1386
1387 inode = file_inode(f.file);
1388 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1389 ret = -EBADF;
1390 goto out_fput;
1391 }
1392 info = MQUEUE_I(inode);
1393
1394 ret = 0;
1395 spin_lock(&info->lock);
1396 if (notification == NULL) {
1397 if (info->notify_owner == task_tgid(current)) {
1398 remove_notification(info);
1399 inode->i_atime = inode->i_ctime = current_time(inode);
1400 }
1401 } else if (info->notify_owner != NULL) {
1402 ret = -EBUSY;
1403 } else {
1404 switch (notification->sigev_notify) {
1405 case SIGEV_NONE:
1406 info->notify.sigev_notify = SIGEV_NONE;
1407 break;
1408 case SIGEV_THREAD:
1409 info->notify_sock = sock;
1410 info->notify_cookie = nc;
1411 sock = NULL;
1412 nc = NULL;
1413 info->notify.sigev_notify = SIGEV_THREAD;
1414 break;
1415 case SIGEV_SIGNAL:
1416 info->notify.sigev_signo = notification->sigev_signo;
1417 info->notify.sigev_value = notification->sigev_value;
1418 info->notify.sigev_notify = SIGEV_SIGNAL;
1419 info->notify_self_exec_id = current->self_exec_id;
1420 break;
1421 }
1422
1423 info->notify_owner = get_pid(task_tgid(current));
1424 info->notify_user_ns = get_user_ns(current_user_ns());
1425 inode->i_atime = inode->i_ctime = current_time(inode);
1426 }
1427 spin_unlock(&info->lock);
1428out_fput:
1429 fdput(f);
1430out:
1431 if (sock)
1432 netlink_detachskb(sock, nc);
1433 else
1434free_skb:
1435 dev_kfree_skb(nc);
1436
1437 return ret;
1438}
1439
1440SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1441 const struct sigevent __user *, u_notification)
1442{
1443 struct sigevent n, *p = NULL;
1444 if (u_notification) {
1445 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1446 return -EFAULT;
1447 p = &n;
1448 }
1449 return do_mq_notify(mqdes, p);
1450}
1451
1452static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1453{
1454 struct fd f;
1455 struct inode *inode;
1456 struct mqueue_inode_info *info;
1457
1458 if (new && (new->mq_flags & (~O_NONBLOCK)))
1459 return -EINVAL;
1460
1461 f = fdget(mqdes);
1462 if (!f.file)
1463 return -EBADF;
1464
1465 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1466 fdput(f);
1467 return -EBADF;
1468 }
1469
1470 inode = file_inode(f.file);
1471 info = MQUEUE_I(inode);
1472
1473 spin_lock(&info->lock);
1474
1475 if (old) {
1476 *old = info->attr;
1477 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1478 }
1479 if (new) {
1480 audit_mq_getsetattr(mqdes, new);
1481 spin_lock(&f.file->f_lock);
1482 if (new->mq_flags & O_NONBLOCK)
1483 f.file->f_flags |= O_NONBLOCK;
1484 else
1485 f.file->f_flags &= ~O_NONBLOCK;
1486 spin_unlock(&f.file->f_lock);
1487
1488 inode->i_atime = inode->i_ctime = current_time(inode);
1489 }
1490
1491 spin_unlock(&info->lock);
1492 fdput(f);
1493 return 0;
1494}
1495
1496SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1497 const struct mq_attr __user *, u_mqstat,
1498 struct mq_attr __user *, u_omqstat)
1499{
1500 int ret;
1501 struct mq_attr mqstat, omqstat;
1502 struct mq_attr *new = NULL, *old = NULL;
1503
1504 if (u_mqstat) {
1505 new = &mqstat;
1506 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1507 return -EFAULT;
1508 }
1509 if (u_omqstat)
1510 old = &omqstat;
1511
1512 ret = do_mq_getsetattr(mqdes, new, old);
1513 if (ret || !old)
1514 return ret;
1515
1516 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1517 return -EFAULT;
1518 return 0;
1519}
1520
1521#ifdef CONFIG_COMPAT
1522
1523struct compat_mq_attr {
1524 compat_long_t mq_flags; /* message queue flags */
1525 compat_long_t mq_maxmsg; /* maximum number of messages */
1526 compat_long_t mq_msgsize; /* maximum message size */
1527 compat_long_t mq_curmsgs; /* number of messages currently queued */
1528 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1529};
1530
1531static inline int get_compat_mq_attr(struct mq_attr *attr,
1532 const struct compat_mq_attr __user *uattr)
1533{
1534 struct compat_mq_attr v;
1535
1536 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1537 return -EFAULT;
1538
1539 memset(attr, 0, sizeof(*attr));
1540 attr->mq_flags = v.mq_flags;
1541 attr->mq_maxmsg = v.mq_maxmsg;
1542 attr->mq_msgsize = v.mq_msgsize;
1543 attr->mq_curmsgs = v.mq_curmsgs;
1544 return 0;
1545}
1546
1547static inline int put_compat_mq_attr(const struct mq_attr *attr,
1548 struct compat_mq_attr __user *uattr)
1549{
1550 struct compat_mq_attr v;
1551
1552 memset(&v, 0, sizeof(v));
1553 v.mq_flags = attr->mq_flags;
1554 v.mq_maxmsg = attr->mq_maxmsg;
1555 v.mq_msgsize = attr->mq_msgsize;
1556 v.mq_curmsgs = attr->mq_curmsgs;
1557 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1558 return -EFAULT;
1559 return 0;
1560}
1561
1562COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1563 int, oflag, compat_mode_t, mode,
1564 struct compat_mq_attr __user *, u_attr)
1565{
1566 struct mq_attr attr, *p = NULL;
1567 if (u_attr && oflag & O_CREAT) {
1568 p = &attr;
1569 if (get_compat_mq_attr(&attr, u_attr))
1570 return -EFAULT;
1571 }
1572 return do_mq_open(u_name, oflag, mode, p);
1573}
1574
1575COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1576 const struct compat_sigevent __user *, u_notification)
1577{
1578 struct sigevent n, *p = NULL;
1579 if (u_notification) {
1580 if (get_compat_sigevent(&n, u_notification))
1581 return -EFAULT;
1582 if (n.sigev_notify == SIGEV_THREAD)
1583 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1584 p = &n;
1585 }
1586 return do_mq_notify(mqdes, p);
1587}
1588
1589COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1590 const struct compat_mq_attr __user *, u_mqstat,
1591 struct compat_mq_attr __user *, u_omqstat)
1592{
1593 int ret;
1594 struct mq_attr mqstat, omqstat;
1595 struct mq_attr *new = NULL, *old = NULL;
1596
1597 if (u_mqstat) {
1598 new = &mqstat;
1599 if (get_compat_mq_attr(new, u_mqstat))
1600 return -EFAULT;
1601 }
1602 if (u_omqstat)
1603 old = &omqstat;
1604
1605 ret = do_mq_getsetattr(mqdes, new, old);
1606 if (ret || !old)
1607 return ret;
1608
1609 if (put_compat_mq_attr(old, u_omqstat))
1610 return -EFAULT;
1611 return 0;
1612}
1613#endif
1614
1615#ifdef CONFIG_COMPAT_32BIT_TIME
1616static int compat_prepare_timeout(const struct old_timespec32 __user *p,
1617 struct timespec64 *ts)
1618{
1619 if (get_old_timespec32(ts, p))
1620 return -EFAULT;
1621 if (!timespec64_valid(ts))
1622 return -EINVAL;
1623 return 0;
1624}
1625
1626SYSCALL_DEFINE5(mq_timedsend_time32, mqd_t, mqdes,
1627 const char __user *, u_msg_ptr,
1628 unsigned int, msg_len, unsigned int, msg_prio,
1629 const struct old_timespec32 __user *, u_abs_timeout)
1630{
1631 struct timespec64 ts, *p = NULL;
1632 if (u_abs_timeout) {
1633 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1634 if (res)
1635 return res;
1636 p = &ts;
1637 }
1638 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1639}
1640
1641SYSCALL_DEFINE5(mq_timedreceive_time32, mqd_t, mqdes,
1642 char __user *, u_msg_ptr,
1643 unsigned int, msg_len, unsigned int __user *, u_msg_prio,
1644 const struct old_timespec32 __user *, u_abs_timeout)
1645{
1646 struct timespec64 ts, *p = NULL;
1647 if (u_abs_timeout) {
1648 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1649 if (res)
1650 return res;
1651 p = &ts;
1652 }
1653 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1654}
1655#endif
1656
1657static const struct inode_operations mqueue_dir_inode_operations = {
1658 .lookup = simple_lookup,
1659 .create = mqueue_create,
1660 .unlink = mqueue_unlink,
1661};
1662
1663static const struct file_operations mqueue_file_operations = {
1664 .flush = mqueue_flush_file,
1665 .poll = mqueue_poll_file,
1666 .read = mqueue_read_file,
1667 .llseek = default_llseek,
1668};
1669
1670static const struct super_operations mqueue_super_ops = {
1671 .alloc_inode = mqueue_alloc_inode,
1672 .free_inode = mqueue_free_inode,
1673 .evict_inode = mqueue_evict_inode,
1674 .statfs = simple_statfs,
1675};
1676
1677static const struct fs_context_operations mqueue_fs_context_ops = {
1678 .free = mqueue_fs_context_free,
1679 .get_tree = mqueue_get_tree,
1680};
1681
1682static struct file_system_type mqueue_fs_type = {
1683 .name = "mqueue",
1684 .init_fs_context = mqueue_init_fs_context,
1685 .kill_sb = kill_litter_super,
1686 .fs_flags = FS_USERNS_MOUNT,
1687};
1688
1689int mq_init_ns(struct ipc_namespace *ns)
1690{
1691 struct vfsmount *m;
1692
1693 ns->mq_queues_count = 0;
1694 ns->mq_queues_max = DFLT_QUEUESMAX;
1695 ns->mq_msg_max = DFLT_MSGMAX;
1696 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1697 ns->mq_msg_default = DFLT_MSG;
1698 ns->mq_msgsize_default = DFLT_MSGSIZE;
1699
1700 m = mq_create_mount(ns);
1701 if (IS_ERR(m))
1702 return PTR_ERR(m);
1703 ns->mq_mnt = m;
1704 return 0;
1705}
1706
1707void mq_clear_sbinfo(struct ipc_namespace *ns)
1708{
1709 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1710}
1711
1712void mq_put_mnt(struct ipc_namespace *ns)
1713{
1714 kern_unmount(ns->mq_mnt);
1715}
1716
1717static int __init init_mqueue_fs(void)
1718{
1719 int error;
1720
1721 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1722 sizeof(struct mqueue_inode_info), 0,
1723 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1724 if (mqueue_inode_cachep == NULL)
1725 return -ENOMEM;
1726
1727 if (!setup_mq_sysctls(&init_ipc_ns)) {
1728 pr_warn("sysctl registration failed\n");
1729 error = -ENOMEM;
1730 goto out_kmem;
1731 }
1732
1733 error = register_filesystem(&mqueue_fs_type);
1734 if (error)
1735 goto out_sysctl;
1736
1737 spin_lock_init(&mq_lock);
1738
1739 error = mq_init_ns(&init_ipc_ns);
1740 if (error)
1741 goto out_filesystem;
1742
1743 return 0;
1744
1745out_filesystem:
1746 unregister_filesystem(&mqueue_fs_type);
1747out_sysctl:
1748 retire_mq_sysctls(&init_ipc_ns);
1749out_kmem:
1750 kmem_cache_destroy(mqueue_inode_cachep);
1751 return error;
1752}
1753
1754device_initcall(init_mqueue_fs);