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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/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);
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 simple_inode_init_ts(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 simple_inode_init_ts(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 mnt_idmap *idmap, 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 simple_inode_init_ts(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 inode *inode = file_inode(filp);
639 struct mqueue_inode_info *info = MQUEUE_I(inode);
640 char buffer[FILENT_SIZE];
641 ssize_t ret;
642
643 spin_lock(&info->lock);
644 snprintf(buffer, sizeof(buffer),
645 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
646 info->qsize,
647 info->notify_owner ? info->notify.sigev_notify : 0,
648 (info->notify_owner &&
649 info->notify.sigev_notify == SIGEV_SIGNAL) ?
650 info->notify.sigev_signo : 0,
651 pid_vnr(info->notify_owner));
652 spin_unlock(&info->lock);
653 buffer[sizeof(buffer)-1] = '\0';
654
655 ret = simple_read_from_buffer(u_data, count, off, buffer,
656 strlen(buffer));
657 if (ret <= 0)
658 return ret;
659
660 inode_set_atime_to_ts(inode, inode_set_ctime_current(inode));
661 return ret;
662}
663
664static int mqueue_flush_file(struct file *filp, fl_owner_t id)
665{
666 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
667
668 spin_lock(&info->lock);
669 if (task_tgid(current) == info->notify_owner)
670 remove_notification(info);
671
672 spin_unlock(&info->lock);
673 return 0;
674}
675
676static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
677{
678 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
679 __poll_t retval = 0;
680
681 poll_wait(filp, &info->wait_q, poll_tab);
682
683 spin_lock(&info->lock);
684 if (info->attr.mq_curmsgs)
685 retval = EPOLLIN | EPOLLRDNORM;
686
687 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
688 retval |= EPOLLOUT | EPOLLWRNORM;
689 spin_unlock(&info->lock);
690
691 return retval;
692}
693
694/* Adds current to info->e_wait_q[sr] before element with smaller prio */
695static void wq_add(struct mqueue_inode_info *info, int sr,
696 struct ext_wait_queue *ewp)
697{
698 struct ext_wait_queue *walk;
699
700 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
701 if (walk->task->prio <= current->prio) {
702 list_add_tail(&ewp->list, &walk->list);
703 return;
704 }
705 }
706 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
707}
708
709/*
710 * Puts current task to sleep. Caller must hold queue lock. After return
711 * lock isn't held.
712 * sr: SEND or RECV
713 */
714static int wq_sleep(struct mqueue_inode_info *info, int sr,
715 ktime_t *timeout, struct ext_wait_queue *ewp)
716 __releases(&info->lock)
717{
718 int retval;
719 signed long time;
720
721 wq_add(info, sr, ewp);
722
723 for (;;) {
724 /* memory barrier not required, we hold info->lock */
725 __set_current_state(TASK_INTERRUPTIBLE);
726
727 spin_unlock(&info->lock);
728 time = schedule_hrtimeout_range_clock(timeout, 0,
729 HRTIMER_MODE_ABS, CLOCK_REALTIME);
730
731 if (READ_ONCE(ewp->state) == STATE_READY) {
732 /* see MQ_BARRIER for purpose/pairing */
733 smp_acquire__after_ctrl_dep();
734 retval = 0;
735 goto out;
736 }
737 spin_lock(&info->lock);
738
739 /* we hold info->lock, so no memory barrier required */
740 if (READ_ONCE(ewp->state) == STATE_READY) {
741 retval = 0;
742 goto out_unlock;
743 }
744 if (signal_pending(current)) {
745 retval = -ERESTARTSYS;
746 break;
747 }
748 if (time == 0) {
749 retval = -ETIMEDOUT;
750 break;
751 }
752 }
753 list_del(&ewp->list);
754out_unlock:
755 spin_unlock(&info->lock);
756out:
757 return retval;
758}
759
760/*
761 * Returns waiting task that should be serviced first or NULL if none exists
762 */
763static struct ext_wait_queue *wq_get_first_waiter(
764 struct mqueue_inode_info *info, int sr)
765{
766 struct list_head *ptr;
767
768 ptr = info->e_wait_q[sr].list.prev;
769 if (ptr == &info->e_wait_q[sr].list)
770 return NULL;
771 return list_entry(ptr, struct ext_wait_queue, list);
772}
773
774
775static inline void set_cookie(struct sk_buff *skb, char code)
776{
777 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
778}
779
780/*
781 * The next function is only to split too long sys_mq_timedsend
782 */
783static void __do_notify(struct mqueue_inode_info *info)
784{
785 /* notification
786 * invoked when there is registered process and there isn't process
787 * waiting synchronously for message AND state of queue changed from
788 * empty to not empty. Here we are sure that no one is waiting
789 * synchronously. */
790 if (info->notify_owner &&
791 info->attr.mq_curmsgs == 1) {
792 switch (info->notify.sigev_notify) {
793 case SIGEV_NONE:
794 break;
795 case SIGEV_SIGNAL: {
796 struct kernel_siginfo sig_i;
797 struct task_struct *task;
798
799 /* do_mq_notify() accepts sigev_signo == 0, why?? */
800 if (!info->notify.sigev_signo)
801 break;
802
803 clear_siginfo(&sig_i);
804 sig_i.si_signo = info->notify.sigev_signo;
805 sig_i.si_errno = 0;
806 sig_i.si_code = SI_MESGQ;
807 sig_i.si_value = info->notify.sigev_value;
808 rcu_read_lock();
809 /* map current pid/uid into info->owner's namespaces */
810 sig_i.si_pid = task_tgid_nr_ns(current,
811 ns_of_pid(info->notify_owner));
812 sig_i.si_uid = from_kuid_munged(info->notify_user_ns,
813 current_uid());
814 /*
815 * We can't use kill_pid_info(), this signal should
816 * bypass check_kill_permission(). It is from kernel
817 * but si_fromuser() can't know this.
818 * We do check the self_exec_id, to avoid sending
819 * signals to programs that don't expect them.
820 */
821 task = pid_task(info->notify_owner, PIDTYPE_TGID);
822 if (task && task->self_exec_id ==
823 info->notify_self_exec_id) {
824 do_send_sig_info(info->notify.sigev_signo,
825 &sig_i, task, PIDTYPE_TGID);
826 }
827 rcu_read_unlock();
828 break;
829 }
830 case SIGEV_THREAD:
831 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
832 netlink_sendskb(info->notify_sock, info->notify_cookie);
833 break;
834 }
835 /* after notification unregisters process */
836 put_pid(info->notify_owner);
837 put_user_ns(info->notify_user_ns);
838 info->notify_owner = NULL;
839 info->notify_user_ns = NULL;
840 }
841 wake_up(&info->wait_q);
842}
843
844static int prepare_timeout(const struct __kernel_timespec __user *u_abs_timeout,
845 struct timespec64 *ts)
846{
847 if (get_timespec64(ts, u_abs_timeout))
848 return -EFAULT;
849 if (!timespec64_valid(ts))
850 return -EINVAL;
851 return 0;
852}
853
854static void remove_notification(struct mqueue_inode_info *info)
855{
856 if (info->notify_owner != NULL &&
857 info->notify.sigev_notify == SIGEV_THREAD) {
858 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
859 netlink_sendskb(info->notify_sock, info->notify_cookie);
860 }
861 put_pid(info->notify_owner);
862 put_user_ns(info->notify_user_ns);
863 info->notify_owner = NULL;
864 info->notify_user_ns = NULL;
865}
866
867static int prepare_open(struct dentry *dentry, int oflag, int ro,
868 umode_t mode, struct filename *name,
869 struct mq_attr *attr)
870{
871 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
872 MAY_READ | MAY_WRITE };
873 int acc;
874
875 if (d_really_is_negative(dentry)) {
876 if (!(oflag & O_CREAT))
877 return -ENOENT;
878 if (ro)
879 return ro;
880 audit_inode_parent_hidden(name, dentry->d_parent);
881 return vfs_mkobj(dentry, mode & ~current_umask(),
882 mqueue_create_attr, attr);
883 }
884 /* it already existed */
885 audit_inode(name, dentry, 0);
886 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
887 return -EEXIST;
888 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
889 return -EINVAL;
890 acc = oflag2acc[oflag & O_ACCMODE];
891 return inode_permission(&nop_mnt_idmap, d_inode(dentry), acc);
892}
893
894static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
895 struct mq_attr *attr)
896{
897 struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
898 struct dentry *root = mnt->mnt_root;
899 struct filename *name;
900 struct path path;
901 int fd, error;
902 int ro;
903
904 audit_mq_open(oflag, mode, attr);
905
906 if (IS_ERR(name = getname(u_name)))
907 return PTR_ERR(name);
908
909 fd = get_unused_fd_flags(O_CLOEXEC);
910 if (fd < 0)
911 goto out_putname;
912
913 ro = mnt_want_write(mnt); /* we'll drop it in any case */
914 inode_lock(d_inode(root));
915 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
916 if (IS_ERR(path.dentry)) {
917 error = PTR_ERR(path.dentry);
918 goto out_putfd;
919 }
920 path.mnt = mntget(mnt);
921 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
922 if (!error) {
923 struct file *file = dentry_open(&path, oflag, current_cred());
924 if (!IS_ERR(file))
925 fd_install(fd, file);
926 else
927 error = PTR_ERR(file);
928 }
929 path_put(&path);
930out_putfd:
931 if (error) {
932 put_unused_fd(fd);
933 fd = error;
934 }
935 inode_unlock(d_inode(root));
936 if (!ro)
937 mnt_drop_write(mnt);
938out_putname:
939 putname(name);
940 return fd;
941}
942
943SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
944 struct mq_attr __user *, u_attr)
945{
946 struct mq_attr attr;
947 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
948 return -EFAULT;
949
950 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
951}
952
953SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
954{
955 int err;
956 struct filename *name;
957 struct dentry *dentry;
958 struct inode *inode = NULL;
959 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
960 struct vfsmount *mnt = ipc_ns->mq_mnt;
961
962 name = getname(u_name);
963 if (IS_ERR(name))
964 return PTR_ERR(name);
965
966 audit_inode_parent_hidden(name, mnt->mnt_root);
967 err = mnt_want_write(mnt);
968 if (err)
969 goto out_name;
970 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
971 dentry = lookup_one_len(name->name, mnt->mnt_root,
972 strlen(name->name));
973 if (IS_ERR(dentry)) {
974 err = PTR_ERR(dentry);
975 goto out_unlock;
976 }
977
978 inode = d_inode(dentry);
979 if (!inode) {
980 err = -ENOENT;
981 } else {
982 ihold(inode);
983 err = vfs_unlink(&nop_mnt_idmap, d_inode(dentry->d_parent),
984 dentry, NULL);
985 }
986 dput(dentry);
987
988out_unlock:
989 inode_unlock(d_inode(mnt->mnt_root));
990 iput(inode);
991 mnt_drop_write(mnt);
992out_name:
993 putname(name);
994
995 return err;
996}
997
998/* Pipelined send and receive functions.
999 *
1000 * If a receiver finds no waiting message, then it registers itself in the
1001 * list of waiting receivers. A sender checks that list before adding the new
1002 * message into the message array. If there is a waiting receiver, then it
1003 * bypasses the message array and directly hands the message over to the
1004 * receiver. The receiver accepts the message and returns without grabbing the
1005 * queue spinlock:
1006 *
1007 * - Set pointer to message.
1008 * - Queue the receiver task for later wakeup (without the info->lock).
1009 * - Update its state to STATE_READY. Now the receiver can continue.
1010 * - Wake up the process after the lock is dropped. Should the process wake up
1011 * before this wakeup (due to a timeout or a signal) it will either see
1012 * STATE_READY and continue or acquire the lock to check the state again.
1013 *
1014 * The same algorithm is used for senders.
1015 */
1016
1017static inline void __pipelined_op(struct wake_q_head *wake_q,
1018 struct mqueue_inode_info *info,
1019 struct ext_wait_queue *this)
1020{
1021 struct task_struct *task;
1022
1023 list_del(&this->list);
1024 task = get_task_struct(this->task);
1025
1026 /* see MQ_BARRIER for purpose/pairing */
1027 smp_store_release(&this->state, STATE_READY);
1028 wake_q_add_safe(wake_q, task);
1029}
1030
1031/* pipelined_send() - send a message directly to the task waiting in
1032 * sys_mq_timedreceive() (without inserting message into a queue).
1033 */
1034static inline void pipelined_send(struct wake_q_head *wake_q,
1035 struct mqueue_inode_info *info,
1036 struct msg_msg *message,
1037 struct ext_wait_queue *receiver)
1038{
1039 receiver->msg = message;
1040 __pipelined_op(wake_q, info, receiver);
1041}
1042
1043/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
1044 * gets its message and put to the queue (we have one free place for sure). */
1045static inline void pipelined_receive(struct wake_q_head *wake_q,
1046 struct mqueue_inode_info *info)
1047{
1048 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
1049
1050 if (!sender) {
1051 /* for poll */
1052 wake_up_interruptible(&info->wait_q);
1053 return;
1054 }
1055 if (msg_insert(sender->msg, info))
1056 return;
1057
1058 __pipelined_op(wake_q, info, sender);
1059}
1060
1061static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
1062 size_t msg_len, unsigned int msg_prio,
1063 struct timespec64 *ts)
1064{
1065 struct fd f;
1066 struct inode *inode;
1067 struct ext_wait_queue wait;
1068 struct ext_wait_queue *receiver;
1069 struct msg_msg *msg_ptr;
1070 struct mqueue_inode_info *info;
1071 ktime_t expires, *timeout = NULL;
1072 struct posix_msg_tree_node *new_leaf = NULL;
1073 int ret = 0;
1074 DEFINE_WAKE_Q(wake_q);
1075
1076 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
1077 return -EINVAL;
1078
1079 if (ts) {
1080 expires = timespec64_to_ktime(*ts);
1081 timeout = &expires;
1082 }
1083
1084 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
1085
1086 f = fdget(mqdes);
1087 if (unlikely(!f.file)) {
1088 ret = -EBADF;
1089 goto out;
1090 }
1091
1092 inode = file_inode(f.file);
1093 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1094 ret = -EBADF;
1095 goto out_fput;
1096 }
1097 info = MQUEUE_I(inode);
1098 audit_file(f.file);
1099
1100 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
1101 ret = -EBADF;
1102 goto out_fput;
1103 }
1104
1105 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1106 ret = -EMSGSIZE;
1107 goto out_fput;
1108 }
1109
1110 /* First try to allocate memory, before doing anything with
1111 * existing queues. */
1112 msg_ptr = load_msg(u_msg_ptr, msg_len);
1113 if (IS_ERR(msg_ptr)) {
1114 ret = PTR_ERR(msg_ptr);
1115 goto out_fput;
1116 }
1117 msg_ptr->m_ts = msg_len;
1118 msg_ptr->m_type = msg_prio;
1119
1120 /*
1121 * msg_insert really wants us to have a valid, spare node struct so
1122 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1123 * fall back to that if necessary.
1124 */
1125 if (!info->node_cache)
1126 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1127
1128 spin_lock(&info->lock);
1129
1130 if (!info->node_cache && new_leaf) {
1131 /* Save our speculative allocation into the cache */
1132 INIT_LIST_HEAD(&new_leaf->msg_list);
1133 info->node_cache = new_leaf;
1134 new_leaf = NULL;
1135 } else {
1136 kfree(new_leaf);
1137 }
1138
1139 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1140 if (f.file->f_flags & O_NONBLOCK) {
1141 ret = -EAGAIN;
1142 } else {
1143 wait.task = current;
1144 wait.msg = (void *) msg_ptr;
1145
1146 /* memory barrier not required, we hold info->lock */
1147 WRITE_ONCE(wait.state, STATE_NONE);
1148 ret = wq_sleep(info, SEND, timeout, &wait);
1149 /*
1150 * wq_sleep must be called with info->lock held, and
1151 * returns with the lock released
1152 */
1153 goto out_free;
1154 }
1155 } else {
1156 receiver = wq_get_first_waiter(info, RECV);
1157 if (receiver) {
1158 pipelined_send(&wake_q, info, msg_ptr, receiver);
1159 } else {
1160 /* adds message to the queue */
1161 ret = msg_insert(msg_ptr, info);
1162 if (ret)
1163 goto out_unlock;
1164 __do_notify(info);
1165 }
1166 simple_inode_init_ts(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 simple_inode_init_ts(inode);
1261
1262 /* There is now free space in queue. */
1263 pipelined_receive(&wake_q, info);
1264 spin_unlock(&info->lock);
1265 wake_up_q(&wake_q);
1266 ret = 0;
1267 }
1268 if (ret == 0) {
1269 ret = msg_ptr->m_ts;
1270
1271 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1272 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1273 ret = -EFAULT;
1274 }
1275 free_msg(msg_ptr);
1276 }
1277out_fput:
1278 fdput(f);
1279out:
1280 return ret;
1281}
1282
1283SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1284 size_t, msg_len, unsigned int, msg_prio,
1285 const struct __kernel_timespec __user *, u_abs_timeout)
1286{
1287 struct timespec64 ts, *p = NULL;
1288 if (u_abs_timeout) {
1289 int res = prepare_timeout(u_abs_timeout, &ts);
1290 if (res)
1291 return res;
1292 p = &ts;
1293 }
1294 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1295}
1296
1297SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1298 size_t, msg_len, unsigned int __user *, u_msg_prio,
1299 const struct __kernel_timespec __user *, u_abs_timeout)
1300{
1301 struct timespec64 ts, *p = NULL;
1302 if (u_abs_timeout) {
1303 int res = prepare_timeout(u_abs_timeout, &ts);
1304 if (res)
1305 return res;
1306 p = &ts;
1307 }
1308 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1309}
1310
1311/*
1312 * Notes: the case when user wants us to deregister (with NULL as pointer)
1313 * and he isn't currently owner of notification, will be silently discarded.
1314 * It isn't explicitly defined in the POSIX.
1315 */
1316static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1317{
1318 int ret;
1319 struct fd f;
1320 struct sock *sock;
1321 struct inode *inode;
1322 struct mqueue_inode_info *info;
1323 struct sk_buff *nc;
1324
1325 audit_mq_notify(mqdes, notification);
1326
1327 nc = NULL;
1328 sock = NULL;
1329 if (notification != NULL) {
1330 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1331 notification->sigev_notify != SIGEV_SIGNAL &&
1332 notification->sigev_notify != SIGEV_THREAD))
1333 return -EINVAL;
1334 if (notification->sigev_notify == SIGEV_SIGNAL &&
1335 !valid_signal(notification->sigev_signo)) {
1336 return -EINVAL;
1337 }
1338 if (notification->sigev_notify == SIGEV_THREAD) {
1339 long timeo;
1340
1341 /* create the notify skb */
1342 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1343 if (!nc)
1344 return -ENOMEM;
1345
1346 if (copy_from_user(nc->data,
1347 notification->sigev_value.sival_ptr,
1348 NOTIFY_COOKIE_LEN)) {
1349 ret = -EFAULT;
1350 goto free_skb;
1351 }
1352
1353 /* TODO: add a header? */
1354 skb_put(nc, NOTIFY_COOKIE_LEN);
1355 /* and attach it to the socket */
1356retry:
1357 f = fdget(notification->sigev_signo);
1358 if (!f.file) {
1359 ret = -EBADF;
1360 goto out;
1361 }
1362 sock = netlink_getsockbyfilp(f.file);
1363 fdput(f);
1364 if (IS_ERR(sock)) {
1365 ret = PTR_ERR(sock);
1366 goto free_skb;
1367 }
1368
1369 timeo = MAX_SCHEDULE_TIMEOUT;
1370 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1371 if (ret == 1) {
1372 sock = NULL;
1373 goto retry;
1374 }
1375 if (ret)
1376 return ret;
1377 }
1378 }
1379
1380 f = fdget(mqdes);
1381 if (!f.file) {
1382 ret = -EBADF;
1383 goto out;
1384 }
1385
1386 inode = file_inode(f.file);
1387 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1388 ret = -EBADF;
1389 goto out_fput;
1390 }
1391 info = MQUEUE_I(inode);
1392
1393 ret = 0;
1394 spin_lock(&info->lock);
1395 if (notification == NULL) {
1396 if (info->notify_owner == task_tgid(current)) {
1397 remove_notification(info);
1398 inode_set_atime_to_ts(inode,
1399 inode_set_ctime_current(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_set_atime_to_ts(inode, inode_set_ctime_current(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_set_atime_to_ts(inode, inode_set_ctime_current(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
1712static int __init init_mqueue_fs(void)
1713{
1714 int error;
1715
1716 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1717 sizeof(struct mqueue_inode_info), 0,
1718 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1719 if (mqueue_inode_cachep == NULL)
1720 return -ENOMEM;
1721
1722 if (!setup_mq_sysctls(&init_ipc_ns)) {
1723 pr_warn("sysctl registration failed\n");
1724 error = -ENOMEM;
1725 goto out_kmem;
1726 }
1727
1728 error = register_filesystem(&mqueue_fs_type);
1729 if (error)
1730 goto out_sysctl;
1731
1732 spin_lock_init(&mq_lock);
1733
1734 error = mq_init_ns(&init_ipc_ns);
1735 if (error)
1736 goto out_filesystem;
1737
1738 return 0;
1739
1740out_filesystem:
1741 unregister_filesystem(&mqueue_fs_type);
1742out_sysctl:
1743 retire_mq_sysctls(&init_ipc_ns);
1744out_kmem:
1745 kmem_cache_destroy(mqueue_inode_cachep);
1746 return error;
1747}
1748
1749device_initcall(init_mqueue_fs);