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