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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/namei.h>
22#include <linux/sysctl.h>
23#include <linux/poll.h>
24#include <linux/mqueue.h>
25#include <linux/msg.h>
26#include <linux/skbuff.h>
27#include <linux/netlink.h>
28#include <linux/syscalls.h>
29#include <linux/audit.h>
30#include <linux/signal.h>
31#include <linux/mutex.h>
32#include <linux/nsproxy.h>
33#include <linux/pid.h>
34#include <linux/ipc_namespace.h>
35#include <linux/slab.h>
36
37#include <net/sock.h>
38#include "util.h"
39
40#define MQUEUE_MAGIC 0x19800202
41#define DIRENT_SIZE 20
42#define FILENT_SIZE 80
43
44#define SEND 0
45#define RECV 1
46
47#define STATE_NONE 0
48#define STATE_PENDING 1
49#define STATE_READY 2
50
51struct ext_wait_queue { /* queue of sleeping tasks */
52 struct task_struct *task;
53 struct list_head list;
54 struct msg_msg *msg; /* ptr of loaded message */
55 int state; /* one of STATE_* values */
56};
57
58struct mqueue_inode_info {
59 spinlock_t lock;
60 struct inode vfs_inode;
61 wait_queue_head_t wait_q;
62
63 struct msg_msg **messages;
64 struct mq_attr attr;
65
66 struct sigevent notify;
67 struct pid* notify_owner;
68 struct user_struct *user; /* user who created, for accounting */
69 struct sock *notify_sock;
70 struct sk_buff *notify_cookie;
71
72 /* for tasks waiting for free space and messages, respectively */
73 struct ext_wait_queue e_wait_q[2];
74
75 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
76};
77
78static const struct inode_operations mqueue_dir_inode_operations;
79static const struct file_operations mqueue_file_operations;
80static const struct super_operations mqueue_super_ops;
81static void remove_notification(struct mqueue_inode_info *info);
82
83static struct kmem_cache *mqueue_inode_cachep;
84
85static struct ctl_table_header * mq_sysctl_table;
86
87static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
88{
89 return container_of(inode, struct mqueue_inode_info, vfs_inode);
90}
91
92/*
93 * This routine should be called with the mq_lock held.
94 */
95static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
96{
97 return get_ipc_ns(inode->i_sb->s_fs_info);
98}
99
100static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
101{
102 struct ipc_namespace *ns;
103
104 spin_lock(&mq_lock);
105 ns = __get_ns_from_inode(inode);
106 spin_unlock(&mq_lock);
107 return ns;
108}
109
110static struct inode *mqueue_get_inode(struct super_block *sb,
111 struct ipc_namespace *ipc_ns, int mode,
112 struct mq_attr *attr)
113{
114 struct user_struct *u = current_user();
115 struct inode *inode;
116 int ret = -ENOMEM;
117
118 inode = new_inode(sb);
119 if (!inode)
120 goto err;
121
122 inode->i_ino = get_next_ino();
123 inode->i_mode = mode;
124 inode->i_uid = current_fsuid();
125 inode->i_gid = current_fsgid();
126 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
127
128 if (S_ISREG(mode)) {
129 struct mqueue_inode_info *info;
130 struct task_struct *p = current;
131 unsigned long mq_bytes, mq_msg_tblsz;
132
133 inode->i_fop = &mqueue_file_operations;
134 inode->i_size = FILENT_SIZE;
135 /* mqueue specific info */
136 info = MQUEUE_I(inode);
137 spin_lock_init(&info->lock);
138 init_waitqueue_head(&info->wait_q);
139 INIT_LIST_HEAD(&info->e_wait_q[0].list);
140 INIT_LIST_HEAD(&info->e_wait_q[1].list);
141 info->notify_owner = NULL;
142 info->qsize = 0;
143 info->user = NULL; /* set when all is ok */
144 memset(&info->attr, 0, sizeof(info->attr));
145 info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
146 info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
147 if (attr) {
148 info->attr.mq_maxmsg = attr->mq_maxmsg;
149 info->attr.mq_msgsize = attr->mq_msgsize;
150 }
151 mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
152 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
153 if (!info->messages)
154 goto out_inode;
155
156 mq_bytes = (mq_msg_tblsz +
157 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
158
159 spin_lock(&mq_lock);
160 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
161 u->mq_bytes + mq_bytes > task_rlimit(p, RLIMIT_MSGQUEUE)) {
162 spin_unlock(&mq_lock);
163 /* mqueue_evict_inode() releases info->messages */
164 ret = -EMFILE;
165 goto out_inode;
166 }
167 u->mq_bytes += mq_bytes;
168 spin_unlock(&mq_lock);
169
170 /* all is ok */
171 info->user = get_uid(u);
172 } else if (S_ISDIR(mode)) {
173 inc_nlink(inode);
174 /* Some things misbehave if size == 0 on a directory */
175 inode->i_size = 2 * DIRENT_SIZE;
176 inode->i_op = &mqueue_dir_inode_operations;
177 inode->i_fop = &simple_dir_operations;
178 }
179
180 return inode;
181out_inode:
182 iput(inode);
183err:
184 return ERR_PTR(ret);
185}
186
187static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
188{
189 struct inode *inode;
190 struct ipc_namespace *ns = data;
191 int error;
192
193 sb->s_blocksize = PAGE_CACHE_SIZE;
194 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
195 sb->s_magic = MQUEUE_MAGIC;
196 sb->s_op = &mqueue_super_ops;
197
198 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO,
199 NULL);
200 if (IS_ERR(inode)) {
201 error = PTR_ERR(inode);
202 goto out;
203 }
204
205 sb->s_root = d_alloc_root(inode);
206 if (!sb->s_root) {
207 iput(inode);
208 error = -ENOMEM;
209 goto out;
210 }
211 error = 0;
212
213out:
214 return error;
215}
216
217static struct dentry *mqueue_mount(struct file_system_type *fs_type,
218 int flags, const char *dev_name,
219 void *data)
220{
221 if (!(flags & MS_KERNMOUNT))
222 data = current->nsproxy->ipc_ns;
223 return mount_ns(fs_type, flags, data, mqueue_fill_super);
224}
225
226static void init_once(void *foo)
227{
228 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
229
230 inode_init_once(&p->vfs_inode);
231}
232
233static struct inode *mqueue_alloc_inode(struct super_block *sb)
234{
235 struct mqueue_inode_info *ei;
236
237 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
238 if (!ei)
239 return NULL;
240 return &ei->vfs_inode;
241}
242
243static void mqueue_i_callback(struct rcu_head *head)
244{
245 struct inode *inode = container_of(head, struct inode, i_rcu);
246 INIT_LIST_HEAD(&inode->i_dentry);
247 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
248}
249
250static void mqueue_destroy_inode(struct inode *inode)
251{
252 call_rcu(&inode->i_rcu, mqueue_i_callback);
253}
254
255static void mqueue_evict_inode(struct inode *inode)
256{
257 struct mqueue_inode_info *info;
258 struct user_struct *user;
259 unsigned long mq_bytes;
260 int i;
261 struct ipc_namespace *ipc_ns;
262
263 end_writeback(inode);
264
265 if (S_ISDIR(inode->i_mode))
266 return;
267
268 ipc_ns = get_ns_from_inode(inode);
269 info = MQUEUE_I(inode);
270 spin_lock(&info->lock);
271 for (i = 0; i < info->attr.mq_curmsgs; i++)
272 free_msg(info->messages[i]);
273 kfree(info->messages);
274 spin_unlock(&info->lock);
275
276 /* Total amount of bytes accounted for the mqueue */
277 mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *)
278 + info->attr.mq_msgsize);
279 user = info->user;
280 if (user) {
281 spin_lock(&mq_lock);
282 user->mq_bytes -= mq_bytes;
283 /*
284 * get_ns_from_inode() ensures that the
285 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
286 * to which we now hold a reference, or it is NULL.
287 * We can't put it here under mq_lock, though.
288 */
289 if (ipc_ns)
290 ipc_ns->mq_queues_count--;
291 spin_unlock(&mq_lock);
292 free_uid(user);
293 }
294 if (ipc_ns)
295 put_ipc_ns(ipc_ns);
296}
297
298static int mqueue_create(struct inode *dir, struct dentry *dentry,
299 int mode, struct nameidata *nd)
300{
301 struct inode *inode;
302 struct mq_attr *attr = dentry->d_fsdata;
303 int error;
304 struct ipc_namespace *ipc_ns;
305
306 spin_lock(&mq_lock);
307 ipc_ns = __get_ns_from_inode(dir);
308 if (!ipc_ns) {
309 error = -EACCES;
310 goto out_unlock;
311 }
312 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
313 !capable(CAP_SYS_RESOURCE)) {
314 error = -ENOSPC;
315 goto out_unlock;
316 }
317 ipc_ns->mq_queues_count++;
318 spin_unlock(&mq_lock);
319
320 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
321 if (IS_ERR(inode)) {
322 error = PTR_ERR(inode);
323 spin_lock(&mq_lock);
324 ipc_ns->mq_queues_count--;
325 goto out_unlock;
326 }
327
328 put_ipc_ns(ipc_ns);
329 dir->i_size += DIRENT_SIZE;
330 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
331
332 d_instantiate(dentry, inode);
333 dget(dentry);
334 return 0;
335out_unlock:
336 spin_unlock(&mq_lock);
337 if (ipc_ns)
338 put_ipc_ns(ipc_ns);
339 return error;
340}
341
342static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
343{
344 struct inode *inode = dentry->d_inode;
345
346 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
347 dir->i_size -= DIRENT_SIZE;
348 drop_nlink(inode);
349 dput(dentry);
350 return 0;
351}
352
353/*
354* This is routine for system read from queue file.
355* To avoid mess with doing here some sort of mq_receive we allow
356* to read only queue size & notification info (the only values
357* that are interesting from user point of view and aren't accessible
358* through std routines)
359*/
360static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
361 size_t count, loff_t *off)
362{
363 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
364 char buffer[FILENT_SIZE];
365 ssize_t ret;
366
367 spin_lock(&info->lock);
368 snprintf(buffer, sizeof(buffer),
369 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
370 info->qsize,
371 info->notify_owner ? info->notify.sigev_notify : 0,
372 (info->notify_owner &&
373 info->notify.sigev_notify == SIGEV_SIGNAL) ?
374 info->notify.sigev_signo : 0,
375 pid_vnr(info->notify_owner));
376 spin_unlock(&info->lock);
377 buffer[sizeof(buffer)-1] = '\0';
378
379 ret = simple_read_from_buffer(u_data, count, off, buffer,
380 strlen(buffer));
381 if (ret <= 0)
382 return ret;
383
384 filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
385 return ret;
386}
387
388static int mqueue_flush_file(struct file *filp, fl_owner_t id)
389{
390 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
391
392 spin_lock(&info->lock);
393 if (task_tgid(current) == info->notify_owner)
394 remove_notification(info);
395
396 spin_unlock(&info->lock);
397 return 0;
398}
399
400static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
401{
402 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
403 int retval = 0;
404
405 poll_wait(filp, &info->wait_q, poll_tab);
406
407 spin_lock(&info->lock);
408 if (info->attr.mq_curmsgs)
409 retval = POLLIN | POLLRDNORM;
410
411 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
412 retval |= POLLOUT | POLLWRNORM;
413 spin_unlock(&info->lock);
414
415 return retval;
416}
417
418/* Adds current to info->e_wait_q[sr] before element with smaller prio */
419static void wq_add(struct mqueue_inode_info *info, int sr,
420 struct ext_wait_queue *ewp)
421{
422 struct ext_wait_queue *walk;
423
424 ewp->task = current;
425
426 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
427 if (walk->task->static_prio <= current->static_prio) {
428 list_add_tail(&ewp->list, &walk->list);
429 return;
430 }
431 }
432 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
433}
434
435/*
436 * Puts current task to sleep. Caller must hold queue lock. After return
437 * lock isn't held.
438 * sr: SEND or RECV
439 */
440static int wq_sleep(struct mqueue_inode_info *info, int sr,
441 ktime_t *timeout, struct ext_wait_queue *ewp)
442{
443 int retval;
444 signed long time;
445
446 wq_add(info, sr, ewp);
447
448 for (;;) {
449 set_current_state(TASK_INTERRUPTIBLE);
450
451 spin_unlock(&info->lock);
452 time = schedule_hrtimeout_range_clock(timeout,
453 HRTIMER_MODE_ABS, 0, CLOCK_REALTIME);
454
455 while (ewp->state == STATE_PENDING)
456 cpu_relax();
457
458 if (ewp->state == STATE_READY) {
459 retval = 0;
460 goto out;
461 }
462 spin_lock(&info->lock);
463 if (ewp->state == STATE_READY) {
464 retval = 0;
465 goto out_unlock;
466 }
467 if (signal_pending(current)) {
468 retval = -ERESTARTSYS;
469 break;
470 }
471 if (time == 0) {
472 retval = -ETIMEDOUT;
473 break;
474 }
475 }
476 list_del(&ewp->list);
477out_unlock:
478 spin_unlock(&info->lock);
479out:
480 return retval;
481}
482
483/*
484 * Returns waiting task that should be serviced first or NULL if none exists
485 */
486static struct ext_wait_queue *wq_get_first_waiter(
487 struct mqueue_inode_info *info, int sr)
488{
489 struct list_head *ptr;
490
491 ptr = info->e_wait_q[sr].list.prev;
492 if (ptr == &info->e_wait_q[sr].list)
493 return NULL;
494 return list_entry(ptr, struct ext_wait_queue, list);
495}
496
497/* Auxiliary functions to manipulate messages' list */
498static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
499{
500 int k;
501
502 k = info->attr.mq_curmsgs - 1;
503 while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
504 info->messages[k + 1] = info->messages[k];
505 k--;
506 }
507 info->attr.mq_curmsgs++;
508 info->qsize += ptr->m_ts;
509 info->messages[k + 1] = ptr;
510}
511
512static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
513{
514 info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
515 return info->messages[info->attr.mq_curmsgs];
516}
517
518static inline void set_cookie(struct sk_buff *skb, char code)
519{
520 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
521}
522
523/*
524 * The next function is only to split too long sys_mq_timedsend
525 */
526static void __do_notify(struct mqueue_inode_info *info)
527{
528 /* notification
529 * invoked when there is registered process and there isn't process
530 * waiting synchronously for message AND state of queue changed from
531 * empty to not empty. Here we are sure that no one is waiting
532 * synchronously. */
533 if (info->notify_owner &&
534 info->attr.mq_curmsgs == 1) {
535 struct siginfo sig_i;
536 switch (info->notify.sigev_notify) {
537 case SIGEV_NONE:
538 break;
539 case SIGEV_SIGNAL:
540 /* sends signal */
541
542 sig_i.si_signo = info->notify.sigev_signo;
543 sig_i.si_errno = 0;
544 sig_i.si_code = SI_MESGQ;
545 sig_i.si_value = info->notify.sigev_value;
546 sig_i.si_pid = task_tgid_nr_ns(current,
547 ns_of_pid(info->notify_owner));
548 sig_i.si_uid = current_uid();
549
550 kill_pid_info(info->notify.sigev_signo,
551 &sig_i, info->notify_owner);
552 break;
553 case SIGEV_THREAD:
554 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
555 netlink_sendskb(info->notify_sock, info->notify_cookie);
556 break;
557 }
558 /* after notification unregisters process */
559 put_pid(info->notify_owner);
560 info->notify_owner = NULL;
561 }
562 wake_up(&info->wait_q);
563}
564
565static int prepare_timeout(const struct timespec __user *u_abs_timeout,
566 ktime_t *expires, struct timespec *ts)
567{
568 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
569 return -EFAULT;
570 if (!timespec_valid(ts))
571 return -EINVAL;
572
573 *expires = timespec_to_ktime(*ts);
574 return 0;
575}
576
577static void remove_notification(struct mqueue_inode_info *info)
578{
579 if (info->notify_owner != NULL &&
580 info->notify.sigev_notify == SIGEV_THREAD) {
581 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
582 netlink_sendskb(info->notify_sock, info->notify_cookie);
583 }
584 put_pid(info->notify_owner);
585 info->notify_owner = NULL;
586}
587
588static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
589{
590 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
591 return 0;
592 if (capable(CAP_SYS_RESOURCE)) {
593 if (attr->mq_maxmsg > HARD_MSGMAX)
594 return 0;
595 } else {
596 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
597 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
598 return 0;
599 }
600 /* check for overflow */
601 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
602 return 0;
603 if ((unsigned long)(attr->mq_maxmsg * (attr->mq_msgsize
604 + sizeof (struct msg_msg *))) <
605 (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
606 return 0;
607 return 1;
608}
609
610/*
611 * Invoked when creating a new queue via sys_mq_open
612 */
613static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
614 struct dentry *dentry, int oflag, mode_t mode,
615 struct mq_attr *attr)
616{
617 const struct cred *cred = current_cred();
618 struct file *result;
619 int ret;
620
621 if (attr) {
622 if (!mq_attr_ok(ipc_ns, attr)) {
623 ret = -EINVAL;
624 goto out;
625 }
626 /* store for use during create */
627 dentry->d_fsdata = attr;
628 }
629
630 mode &= ~current_umask();
631 ret = mnt_want_write(ipc_ns->mq_mnt);
632 if (ret)
633 goto out;
634 ret = vfs_create(dir->d_inode, dentry, mode, NULL);
635 dentry->d_fsdata = NULL;
636 if (ret)
637 goto out_drop_write;
638
639 result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
640 /*
641 * dentry_open() took a persistent mnt_want_write(),
642 * so we can now drop this one.
643 */
644 mnt_drop_write(ipc_ns->mq_mnt);
645 return result;
646
647out_drop_write:
648 mnt_drop_write(ipc_ns->mq_mnt);
649out:
650 dput(dentry);
651 mntput(ipc_ns->mq_mnt);
652 return ERR_PTR(ret);
653}
654
655/* Opens existing queue */
656static struct file *do_open(struct ipc_namespace *ipc_ns,
657 struct dentry *dentry, int oflag)
658{
659 int ret;
660 const struct cred *cred = current_cred();
661
662 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
663 MAY_READ | MAY_WRITE };
664
665 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
666 ret = -EINVAL;
667 goto err;
668 }
669
670 if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
671 ret = -EACCES;
672 goto err;
673 }
674
675 return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
676
677err:
678 dput(dentry);
679 mntput(ipc_ns->mq_mnt);
680 return ERR_PTR(ret);
681}
682
683SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
684 struct mq_attr __user *, u_attr)
685{
686 struct dentry *dentry;
687 struct file *filp;
688 char *name;
689 struct mq_attr attr;
690 int fd, error;
691 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
692
693 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
694 return -EFAULT;
695
696 audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
697
698 if (IS_ERR(name = getname(u_name)))
699 return PTR_ERR(name);
700
701 fd = get_unused_fd_flags(O_CLOEXEC);
702 if (fd < 0)
703 goto out_putname;
704
705 mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
706 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
707 if (IS_ERR(dentry)) {
708 error = PTR_ERR(dentry);
709 goto out_putfd;
710 }
711 mntget(ipc_ns->mq_mnt);
712
713 if (oflag & O_CREAT) {
714 if (dentry->d_inode) { /* entry already exists */
715 audit_inode(name, dentry);
716 if (oflag & O_EXCL) {
717 error = -EEXIST;
718 goto out;
719 }
720 filp = do_open(ipc_ns, dentry, oflag);
721 } else {
722 filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
723 dentry, oflag, mode,
724 u_attr ? &attr : NULL);
725 }
726 } else {
727 if (!dentry->d_inode) {
728 error = -ENOENT;
729 goto out;
730 }
731 audit_inode(name, dentry);
732 filp = do_open(ipc_ns, dentry, oflag);
733 }
734
735 if (IS_ERR(filp)) {
736 error = PTR_ERR(filp);
737 goto out_putfd;
738 }
739
740 fd_install(fd, filp);
741 goto out_upsem;
742
743out:
744 dput(dentry);
745 mntput(ipc_ns->mq_mnt);
746out_putfd:
747 put_unused_fd(fd);
748 fd = error;
749out_upsem:
750 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
751out_putname:
752 putname(name);
753 return fd;
754}
755
756SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
757{
758 int err;
759 char *name;
760 struct dentry *dentry;
761 struct inode *inode = NULL;
762 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
763
764 name = getname(u_name);
765 if (IS_ERR(name))
766 return PTR_ERR(name);
767
768 mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
769 I_MUTEX_PARENT);
770 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
771 if (IS_ERR(dentry)) {
772 err = PTR_ERR(dentry);
773 goto out_unlock;
774 }
775
776 if (!dentry->d_inode) {
777 err = -ENOENT;
778 goto out_err;
779 }
780
781 inode = dentry->d_inode;
782 if (inode)
783 ihold(inode);
784 err = mnt_want_write(ipc_ns->mq_mnt);
785 if (err)
786 goto out_err;
787 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
788 mnt_drop_write(ipc_ns->mq_mnt);
789out_err:
790 dput(dentry);
791
792out_unlock:
793 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
794 putname(name);
795 if (inode)
796 iput(inode);
797
798 return err;
799}
800
801/* Pipelined send and receive functions.
802 *
803 * If a receiver finds no waiting message, then it registers itself in the
804 * list of waiting receivers. A sender checks that list before adding the new
805 * message into the message array. If there is a waiting receiver, then it
806 * bypasses the message array and directly hands the message over to the
807 * receiver.
808 * The receiver accepts the message and returns without grabbing the queue
809 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
810 * are necessary. The same algorithm is used for sysv semaphores, see
811 * ipc/sem.c for more details.
812 *
813 * The same algorithm is used for senders.
814 */
815
816/* pipelined_send() - send a message directly to the task waiting in
817 * sys_mq_timedreceive() (without inserting message into a queue).
818 */
819static inline void pipelined_send(struct mqueue_inode_info *info,
820 struct msg_msg *message,
821 struct ext_wait_queue *receiver)
822{
823 receiver->msg = message;
824 list_del(&receiver->list);
825 receiver->state = STATE_PENDING;
826 wake_up_process(receiver->task);
827 smp_wmb();
828 receiver->state = STATE_READY;
829}
830
831/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
832 * gets its message and put to the queue (we have one free place for sure). */
833static inline void pipelined_receive(struct mqueue_inode_info *info)
834{
835 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
836
837 if (!sender) {
838 /* for poll */
839 wake_up_interruptible(&info->wait_q);
840 return;
841 }
842 msg_insert(sender->msg, info);
843 list_del(&sender->list);
844 sender->state = STATE_PENDING;
845 wake_up_process(sender->task);
846 smp_wmb();
847 sender->state = STATE_READY;
848}
849
850SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
851 size_t, msg_len, unsigned int, msg_prio,
852 const struct timespec __user *, u_abs_timeout)
853{
854 struct file *filp;
855 struct inode *inode;
856 struct ext_wait_queue wait;
857 struct ext_wait_queue *receiver;
858 struct msg_msg *msg_ptr;
859 struct mqueue_inode_info *info;
860 ktime_t expires, *timeout = NULL;
861 struct timespec ts;
862 int ret;
863
864 if (u_abs_timeout) {
865 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
866 if (res)
867 return res;
868 timeout = &expires;
869 }
870
871 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
872 return -EINVAL;
873
874 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
875
876 filp = fget(mqdes);
877 if (unlikely(!filp)) {
878 ret = -EBADF;
879 goto out;
880 }
881
882 inode = filp->f_path.dentry->d_inode;
883 if (unlikely(filp->f_op != &mqueue_file_operations)) {
884 ret = -EBADF;
885 goto out_fput;
886 }
887 info = MQUEUE_I(inode);
888 audit_inode(NULL, filp->f_path.dentry);
889
890 if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
891 ret = -EBADF;
892 goto out_fput;
893 }
894
895 if (unlikely(msg_len > info->attr.mq_msgsize)) {
896 ret = -EMSGSIZE;
897 goto out_fput;
898 }
899
900 /* First try to allocate memory, before doing anything with
901 * existing queues. */
902 msg_ptr = load_msg(u_msg_ptr, msg_len);
903 if (IS_ERR(msg_ptr)) {
904 ret = PTR_ERR(msg_ptr);
905 goto out_fput;
906 }
907 msg_ptr->m_ts = msg_len;
908 msg_ptr->m_type = msg_prio;
909
910 spin_lock(&info->lock);
911
912 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
913 if (filp->f_flags & O_NONBLOCK) {
914 spin_unlock(&info->lock);
915 ret = -EAGAIN;
916 } else {
917 wait.task = current;
918 wait.msg = (void *) msg_ptr;
919 wait.state = STATE_NONE;
920 ret = wq_sleep(info, SEND, timeout, &wait);
921 }
922 if (ret < 0)
923 free_msg(msg_ptr);
924 } else {
925 receiver = wq_get_first_waiter(info, RECV);
926 if (receiver) {
927 pipelined_send(info, msg_ptr, receiver);
928 } else {
929 /* adds message to the queue */
930 msg_insert(msg_ptr, info);
931 __do_notify(info);
932 }
933 inode->i_atime = inode->i_mtime = inode->i_ctime =
934 CURRENT_TIME;
935 spin_unlock(&info->lock);
936 ret = 0;
937 }
938out_fput:
939 fput(filp);
940out:
941 return ret;
942}
943
944SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
945 size_t, msg_len, unsigned int __user *, u_msg_prio,
946 const struct timespec __user *, u_abs_timeout)
947{
948 ssize_t ret;
949 struct msg_msg *msg_ptr;
950 struct file *filp;
951 struct inode *inode;
952 struct mqueue_inode_info *info;
953 struct ext_wait_queue wait;
954 ktime_t expires, *timeout = NULL;
955 struct timespec ts;
956
957 if (u_abs_timeout) {
958 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
959 if (res)
960 return res;
961 timeout = &expires;
962 }
963
964 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
965
966 filp = fget(mqdes);
967 if (unlikely(!filp)) {
968 ret = -EBADF;
969 goto out;
970 }
971
972 inode = filp->f_path.dentry->d_inode;
973 if (unlikely(filp->f_op != &mqueue_file_operations)) {
974 ret = -EBADF;
975 goto out_fput;
976 }
977 info = MQUEUE_I(inode);
978 audit_inode(NULL, filp->f_path.dentry);
979
980 if (unlikely(!(filp->f_mode & FMODE_READ))) {
981 ret = -EBADF;
982 goto out_fput;
983 }
984
985 /* checks if buffer is big enough */
986 if (unlikely(msg_len < info->attr.mq_msgsize)) {
987 ret = -EMSGSIZE;
988 goto out_fput;
989 }
990
991 spin_lock(&info->lock);
992 if (info->attr.mq_curmsgs == 0) {
993 if (filp->f_flags & O_NONBLOCK) {
994 spin_unlock(&info->lock);
995 ret = -EAGAIN;
996 } else {
997 wait.task = current;
998 wait.state = STATE_NONE;
999 ret = wq_sleep(info, RECV, timeout, &wait);
1000 msg_ptr = wait.msg;
1001 }
1002 } else {
1003 msg_ptr = msg_get(info);
1004
1005 inode->i_atime = inode->i_mtime = inode->i_ctime =
1006 CURRENT_TIME;
1007
1008 /* There is now free space in queue. */
1009 pipelined_receive(info);
1010 spin_unlock(&info->lock);
1011 ret = 0;
1012 }
1013 if (ret == 0) {
1014 ret = msg_ptr->m_ts;
1015
1016 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1017 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1018 ret = -EFAULT;
1019 }
1020 free_msg(msg_ptr);
1021 }
1022out_fput:
1023 fput(filp);
1024out:
1025 return ret;
1026}
1027
1028/*
1029 * Notes: the case when user wants us to deregister (with NULL as pointer)
1030 * and he isn't currently owner of notification, will be silently discarded.
1031 * It isn't explicitly defined in the POSIX.
1032 */
1033SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1034 const struct sigevent __user *, u_notification)
1035{
1036 int ret;
1037 struct file *filp;
1038 struct sock *sock;
1039 struct inode *inode;
1040 struct sigevent notification;
1041 struct mqueue_inode_info *info;
1042 struct sk_buff *nc;
1043
1044 if (u_notification) {
1045 if (copy_from_user(¬ification, u_notification,
1046 sizeof(struct sigevent)))
1047 return -EFAULT;
1048 }
1049
1050 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL);
1051
1052 nc = NULL;
1053 sock = NULL;
1054 if (u_notification != NULL) {
1055 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1056 notification.sigev_notify != SIGEV_SIGNAL &&
1057 notification.sigev_notify != SIGEV_THREAD))
1058 return -EINVAL;
1059 if (notification.sigev_notify == SIGEV_SIGNAL &&
1060 !valid_signal(notification.sigev_signo)) {
1061 return -EINVAL;
1062 }
1063 if (notification.sigev_notify == SIGEV_THREAD) {
1064 long timeo;
1065
1066 /* create the notify skb */
1067 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1068 if (!nc) {
1069 ret = -ENOMEM;
1070 goto out;
1071 }
1072 if (copy_from_user(nc->data,
1073 notification.sigev_value.sival_ptr,
1074 NOTIFY_COOKIE_LEN)) {
1075 ret = -EFAULT;
1076 goto out;
1077 }
1078
1079 /* TODO: add a header? */
1080 skb_put(nc, NOTIFY_COOKIE_LEN);
1081 /* and attach it to the socket */
1082retry:
1083 filp = fget(notification.sigev_signo);
1084 if (!filp) {
1085 ret = -EBADF;
1086 goto out;
1087 }
1088 sock = netlink_getsockbyfilp(filp);
1089 fput(filp);
1090 if (IS_ERR(sock)) {
1091 ret = PTR_ERR(sock);
1092 sock = NULL;
1093 goto out;
1094 }
1095
1096 timeo = MAX_SCHEDULE_TIMEOUT;
1097 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1098 if (ret == 1)
1099 goto retry;
1100 if (ret) {
1101 sock = NULL;
1102 nc = NULL;
1103 goto out;
1104 }
1105 }
1106 }
1107
1108 filp = fget(mqdes);
1109 if (!filp) {
1110 ret = -EBADF;
1111 goto out;
1112 }
1113
1114 inode = filp->f_path.dentry->d_inode;
1115 if (unlikely(filp->f_op != &mqueue_file_operations)) {
1116 ret = -EBADF;
1117 goto out_fput;
1118 }
1119 info = MQUEUE_I(inode);
1120
1121 ret = 0;
1122 spin_lock(&info->lock);
1123 if (u_notification == NULL) {
1124 if (info->notify_owner == task_tgid(current)) {
1125 remove_notification(info);
1126 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1127 }
1128 } else if (info->notify_owner != NULL) {
1129 ret = -EBUSY;
1130 } else {
1131 switch (notification.sigev_notify) {
1132 case SIGEV_NONE:
1133 info->notify.sigev_notify = SIGEV_NONE;
1134 break;
1135 case SIGEV_THREAD:
1136 info->notify_sock = sock;
1137 info->notify_cookie = nc;
1138 sock = NULL;
1139 nc = NULL;
1140 info->notify.sigev_notify = SIGEV_THREAD;
1141 break;
1142 case SIGEV_SIGNAL:
1143 info->notify.sigev_signo = notification.sigev_signo;
1144 info->notify.sigev_value = notification.sigev_value;
1145 info->notify.sigev_notify = SIGEV_SIGNAL;
1146 break;
1147 }
1148
1149 info->notify_owner = get_pid(task_tgid(current));
1150 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1151 }
1152 spin_unlock(&info->lock);
1153out_fput:
1154 fput(filp);
1155out:
1156 if (sock) {
1157 netlink_detachskb(sock, nc);
1158 } else if (nc) {
1159 dev_kfree_skb(nc);
1160 }
1161 return ret;
1162}
1163
1164SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1165 const struct mq_attr __user *, u_mqstat,
1166 struct mq_attr __user *, u_omqstat)
1167{
1168 int ret;
1169 struct mq_attr mqstat, omqstat;
1170 struct file *filp;
1171 struct inode *inode;
1172 struct mqueue_inode_info *info;
1173
1174 if (u_mqstat != NULL) {
1175 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1176 return -EFAULT;
1177 if (mqstat.mq_flags & (~O_NONBLOCK))
1178 return -EINVAL;
1179 }
1180
1181 filp = fget(mqdes);
1182 if (!filp) {
1183 ret = -EBADF;
1184 goto out;
1185 }
1186
1187 inode = filp->f_path.dentry->d_inode;
1188 if (unlikely(filp->f_op != &mqueue_file_operations)) {
1189 ret = -EBADF;
1190 goto out_fput;
1191 }
1192 info = MQUEUE_I(inode);
1193
1194 spin_lock(&info->lock);
1195
1196 omqstat = info->attr;
1197 omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1198 if (u_mqstat) {
1199 audit_mq_getsetattr(mqdes, &mqstat);
1200 spin_lock(&filp->f_lock);
1201 if (mqstat.mq_flags & O_NONBLOCK)
1202 filp->f_flags |= O_NONBLOCK;
1203 else
1204 filp->f_flags &= ~O_NONBLOCK;
1205 spin_unlock(&filp->f_lock);
1206
1207 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1208 }
1209
1210 spin_unlock(&info->lock);
1211
1212 ret = 0;
1213 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1214 sizeof(struct mq_attr)))
1215 ret = -EFAULT;
1216
1217out_fput:
1218 fput(filp);
1219out:
1220 return ret;
1221}
1222
1223static const struct inode_operations mqueue_dir_inode_operations = {
1224 .lookup = simple_lookup,
1225 .create = mqueue_create,
1226 .unlink = mqueue_unlink,
1227};
1228
1229static const struct file_operations mqueue_file_operations = {
1230 .flush = mqueue_flush_file,
1231 .poll = mqueue_poll_file,
1232 .read = mqueue_read_file,
1233 .llseek = default_llseek,
1234};
1235
1236static const struct super_operations mqueue_super_ops = {
1237 .alloc_inode = mqueue_alloc_inode,
1238 .destroy_inode = mqueue_destroy_inode,
1239 .evict_inode = mqueue_evict_inode,
1240 .statfs = simple_statfs,
1241};
1242
1243static struct file_system_type mqueue_fs_type = {
1244 .name = "mqueue",
1245 .mount = mqueue_mount,
1246 .kill_sb = kill_litter_super,
1247};
1248
1249int mq_init_ns(struct ipc_namespace *ns)
1250{
1251 ns->mq_queues_count = 0;
1252 ns->mq_queues_max = DFLT_QUEUESMAX;
1253 ns->mq_msg_max = DFLT_MSGMAX;
1254 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1255
1256 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1257 if (IS_ERR(ns->mq_mnt)) {
1258 int err = PTR_ERR(ns->mq_mnt);
1259 ns->mq_mnt = NULL;
1260 return err;
1261 }
1262 return 0;
1263}
1264
1265void mq_clear_sbinfo(struct ipc_namespace *ns)
1266{
1267 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1268}
1269
1270void mq_put_mnt(struct ipc_namespace *ns)
1271{
1272 mntput(ns->mq_mnt);
1273}
1274
1275static int __init init_mqueue_fs(void)
1276{
1277 int error;
1278
1279 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1280 sizeof(struct mqueue_inode_info), 0,
1281 SLAB_HWCACHE_ALIGN, init_once);
1282 if (mqueue_inode_cachep == NULL)
1283 return -ENOMEM;
1284
1285 /* ignore failures - they are not fatal */
1286 mq_sysctl_table = mq_register_sysctl_table();
1287
1288 error = register_filesystem(&mqueue_fs_type);
1289 if (error)
1290 goto out_sysctl;
1291
1292 spin_lock_init(&mq_lock);
1293
1294 init_ipc_ns.mq_mnt = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);
1295 if (IS_ERR(init_ipc_ns.mq_mnt)) {
1296 error = PTR_ERR(init_ipc_ns.mq_mnt);
1297 goto out_filesystem;
1298 }
1299
1300 return 0;
1301
1302out_filesystem:
1303 unregister_filesystem(&mqueue_fs_type);
1304out_sysctl:
1305 if (mq_sysctl_table)
1306 unregister_sysctl_table(mq_sysctl_table);
1307 kmem_cache_destroy(mqueue_inode_cachep);
1308 return error;
1309}
1310
1311__initcall(init_mqueue_fs);