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
46 struct 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
61 struct 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
127 struct 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
134 struct 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
158 static struct file_system_type mqueue_fs_type;
159 static const struct inode_operations mqueue_dir_inode_operations;
160 static const struct file_operations mqueue_file_operations;
161 static const struct super_operations mqueue_super_ops;
162 static const struct fs_context_operations mqueue_fs_context_ops;
163 static void remove_notification(struct mqueue_inode_info *info);
164
165 static struct kmem_cache *mqueue_inode_cachep;
166
167 static 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 */
175 static 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
180 static 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 */
191 static 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);
226 insert_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
233 static 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
248 static 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
254 try_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
290 static 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;
398 out_inode:
399 iput(inode);
400 err:
401 return ERR_PTR(ret);
402 }
403
404 static 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
425 static 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
440 static 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
448 static 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 */
468 static 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
490 static void init_once(void *foo)
491 {
492 struct mqueue_inode_info *p = foo;
493
494 inode_init_once(&p->vfs_inode);
495 }
496
497 static 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
507 static void mqueue_free_inode(struct inode *inode)
508 {
509 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
510 }
511
512 static 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
566 static 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;
604 out_unlock:
605 spin_unlock(&mq_lock);
606 if (ipc_ns)
607 put_ipc_ns(ipc_ns);
608 return error;
609 }
610
611 static 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
617 static 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 */
635 static 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
664 static 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
676 static __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 */
695 static 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 */
714 static 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);
754 out_unlock:
755 spin_unlock(&info->lock);
756 out:
757 return retval;
758 }
759
760 /*
761 * Returns waiting task that should be serviced first or NULL if none exists
762 */
763 static 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
775 static 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 */
783 static 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
844 static 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
854 static 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
867 static 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
894 static 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 name = getname(u_name);
907 if (IS_ERR(name))
908 return PTR_ERR(name);
909
910 fd = get_unused_fd_flags(O_CLOEXEC);
911 if (fd < 0)
912 goto out_putname;
913
914 ro = mnt_want_write(mnt); /* we'll drop it in any case */
915 inode_lock(d_inode(root));
916 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
917 if (IS_ERR(path.dentry)) {
918 error = PTR_ERR(path.dentry);
919 goto out_putfd;
920 }
921 path.mnt = mntget(mnt);
922 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
923 if (!error) {
924 struct file *file = dentry_open(&path, oflag, current_cred());
925 if (!IS_ERR(file))
926 fd_install(fd, file);
927 else
928 error = PTR_ERR(file);
929 }
930 path_put(&path);
931 out_putfd:
932 if (error) {
933 put_unused_fd(fd);
934 fd = error;
935 }
936 inode_unlock(d_inode(root));
937 if (!ro)
938 mnt_drop_write(mnt);
939 out_putname:
940 putname(name);
941 return fd;
942 }
943
944 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
945 struct mq_attr __user *, u_attr)
946 {
947 struct mq_attr attr;
948 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
949 return -EFAULT;
950
951 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
952 }
953
954 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
955 {
956 int err;
957 struct filename *name;
958 struct dentry *dentry;
959 struct inode *inode = NULL;
960 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
961 struct vfsmount *mnt = ipc_ns->mq_mnt;
962
963 name = getname(u_name);
964 if (IS_ERR(name))
965 return PTR_ERR(name);
966
967 audit_inode_parent_hidden(name, mnt->mnt_root);
968 err = mnt_want_write(mnt);
969 if (err)
970 goto out_name;
971 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
972 dentry = lookup_one_len(name->name, mnt->mnt_root,
973 strlen(name->name));
974 if (IS_ERR(dentry)) {
975 err = PTR_ERR(dentry);
976 goto out_unlock;
977 }
978
979 inode = d_inode(dentry);
980 if (!inode) {
981 err = -ENOENT;
982 } else {
983 ihold(inode);
984 err = vfs_unlink(&nop_mnt_idmap, d_inode(dentry->d_parent),
985 dentry, NULL);
986 }
987 dput(dentry);
988
989 out_unlock:
990 inode_unlock(d_inode(mnt->mnt_root));
991 iput(inode);
992 mnt_drop_write(mnt);
993 out_name:
994 putname(name);
995
996 return err;
997 }
998
999 /* Pipelined send and receive functions.
1000 *
1001 * If a receiver finds no waiting message, then it registers itself in the
1002 * list of waiting receivers. A sender checks that list before adding the new
1003 * message into the message array. If there is a waiting receiver, then it
1004 * bypasses the message array and directly hands the message over to the
1005 * receiver. The receiver accepts the message and returns without grabbing the
1006 * queue spinlock:
1007 *
1008 * - Set pointer to message.
1009 * - Queue the receiver task for later wakeup (without the info->lock).
1010 * - Update its state to STATE_READY. Now the receiver can continue.
1011 * - Wake up the process after the lock is dropped. Should the process wake up
1012 * before this wakeup (due to a timeout or a signal) it will either see
1013 * STATE_READY and continue or acquire the lock to check the state again.
1014 *
1015 * The same algorithm is used for senders.
1016 */
1017
1018 static inline void __pipelined_op(struct wake_q_head *wake_q,
1019 struct mqueue_inode_info *info,
1020 struct ext_wait_queue *this)
1021 {
1022 struct task_struct *task;
1023
1024 list_del(&this->list);
1025 task = get_task_struct(this->task);
1026
1027 /* see MQ_BARRIER for purpose/pairing */
1028 smp_store_release(&this->state, STATE_READY);
1029 wake_q_add_safe(wake_q, task);
1030 }
1031
1032 /* pipelined_send() - send a message directly to the task waiting in
1033 * sys_mq_timedreceive() (without inserting message into a queue).
1034 */
1035 static inline void pipelined_send(struct wake_q_head *wake_q,
1036 struct mqueue_inode_info *info,
1037 struct msg_msg *message,
1038 struct ext_wait_queue *receiver)
1039 {
1040 receiver->msg = message;
1041 __pipelined_op(wake_q, info, receiver);
1042 }
1043
1044 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
1045 * gets its message and put to the queue (we have one free place for sure). */
1046 static inline void pipelined_receive(struct wake_q_head *wake_q,
1047 struct mqueue_inode_info *info)
1048 {
1049 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
1050
1051 if (!sender) {
1052 /* for poll */
1053 wake_up_interruptible(&info->wait_q);
1054 return;
1055 }
1056 if (msg_insert(sender->msg, info))
1057 return;
1058
1059 __pipelined_op(wake_q, info, sender);
1060 }
1061
1062 static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
1063 size_t msg_len, unsigned int msg_prio,
1064 struct timespec64 *ts)
1065 {
1066 struct fd f;
1067 struct inode *inode;
1068 struct ext_wait_queue wait;
1069 struct ext_wait_queue *receiver;
1070 struct msg_msg *msg_ptr;
1071 struct mqueue_inode_info *info;
1072 ktime_t expires, *timeout = NULL;
1073 struct posix_msg_tree_node *new_leaf = NULL;
1074 int ret = 0;
1075 DEFINE_WAKE_Q(wake_q);
1076
1077 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
1078 return -EINVAL;
1079
1080 if (ts) {
1081 expires = timespec64_to_ktime(*ts);
1082 timeout = &expires;
1083 }
1084
1085 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
1086
1087 f = fdget(mqdes);
1088 if (unlikely(!f.file)) {
1089 ret = -EBADF;
1090 goto out;
1091 }
1092
1093 inode = file_inode(f.file);
1094 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1095 ret = -EBADF;
1096 goto out_fput;
1097 }
1098 info = MQUEUE_I(inode);
1099 audit_file(f.file);
1100
1101 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
1102 ret = -EBADF;
1103 goto out_fput;
1104 }
1105
1106 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1107 ret = -EMSGSIZE;
1108 goto out_fput;
1109 }
1110
1111 /* First try to allocate memory, before doing anything with
1112 * existing queues. */
1113 msg_ptr = load_msg(u_msg_ptr, msg_len);
1114 if (IS_ERR(msg_ptr)) {
1115 ret = PTR_ERR(msg_ptr);
1116 goto out_fput;
1117 }
1118 msg_ptr->m_ts = msg_len;
1119 msg_ptr->m_type = msg_prio;
1120
1121 /*
1122 * msg_insert really wants us to have a valid, spare node struct so
1123 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1124 * fall back to that if necessary.
1125 */
1126 if (!info->node_cache)
1127 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1128
1129 spin_lock(&info->lock);
1130
1131 if (!info->node_cache && new_leaf) {
1132 /* Save our speculative allocation into the cache */
1133 INIT_LIST_HEAD(&new_leaf->msg_list);
1134 info->node_cache = new_leaf;
1135 new_leaf = NULL;
1136 } else {
1137 kfree(new_leaf);
1138 }
1139
1140 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1141 if (f.file->f_flags & O_NONBLOCK) {
1142 ret = -EAGAIN;
1143 } else {
1144 wait.task = current;
1145 wait.msg = (void *) msg_ptr;
1146
1147 /* memory barrier not required, we hold info->lock */
1148 WRITE_ONCE(wait.state, STATE_NONE);
1149 ret = wq_sleep(info, SEND, timeout, &wait);
1150 /*
1151 * wq_sleep must be called with info->lock held, and
1152 * returns with the lock released
1153 */
1154 goto out_free;
1155 }
1156 } else {
1157 receiver = wq_get_first_waiter(info, RECV);
1158 if (receiver) {
1159 pipelined_send(&wake_q, info, msg_ptr, receiver);
1160 } else {
1161 /* adds message to the queue */
1162 ret = msg_insert(msg_ptr, info);
1163 if (ret)
1164 goto out_unlock;
1165 __do_notify(info);
1166 }
1167 simple_inode_init_ts(inode);
1168 }
1169 out_unlock:
1170 spin_unlock(&info->lock);
1171 wake_up_q(&wake_q);
1172 out_free:
1173 if (ret)
1174 free_msg(msg_ptr);
1175 out_fput:
1176 fdput(f);
1177 out:
1178 return ret;
1179 }
1180
1181 static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1182 size_t msg_len, unsigned int __user *u_msg_prio,
1183 struct timespec64 *ts)
1184 {
1185 ssize_t ret;
1186 struct msg_msg *msg_ptr;
1187 struct fd f;
1188 struct inode *inode;
1189 struct mqueue_inode_info *info;
1190 struct ext_wait_queue wait;
1191 ktime_t expires, *timeout = NULL;
1192 struct posix_msg_tree_node *new_leaf = NULL;
1193
1194 if (ts) {
1195 expires = timespec64_to_ktime(*ts);
1196 timeout = &expires;
1197 }
1198
1199 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1200
1201 f = fdget(mqdes);
1202 if (unlikely(!f.file)) {
1203 ret = -EBADF;
1204 goto out;
1205 }
1206
1207 inode = file_inode(f.file);
1208 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1209 ret = -EBADF;
1210 goto out_fput;
1211 }
1212 info = MQUEUE_I(inode);
1213 audit_file(f.file);
1214
1215 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1216 ret = -EBADF;
1217 goto out_fput;
1218 }
1219
1220 /* checks if buffer is big enough */
1221 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1222 ret = -EMSGSIZE;
1223 goto out_fput;
1224 }
1225
1226 /*
1227 * msg_insert really wants us to have a valid, spare node struct so
1228 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1229 * fall back to that if necessary.
1230 */
1231 if (!info->node_cache)
1232 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1233
1234 spin_lock(&info->lock);
1235
1236 if (!info->node_cache && new_leaf) {
1237 /* Save our speculative allocation into the cache */
1238 INIT_LIST_HEAD(&new_leaf->msg_list);
1239 info->node_cache = new_leaf;
1240 } else {
1241 kfree(new_leaf);
1242 }
1243
1244 if (info->attr.mq_curmsgs == 0) {
1245 if (f.file->f_flags & O_NONBLOCK) {
1246 spin_unlock(&info->lock);
1247 ret = -EAGAIN;
1248 } else {
1249 wait.task = current;
1250
1251 /* memory barrier not required, we hold info->lock */
1252 WRITE_ONCE(wait.state, STATE_NONE);
1253 ret = wq_sleep(info, RECV, timeout, &wait);
1254 msg_ptr = wait.msg;
1255 }
1256 } else {
1257 DEFINE_WAKE_Q(wake_q);
1258
1259 msg_ptr = msg_get(info);
1260
1261 simple_inode_init_ts(inode);
1262
1263 /* There is now free space in queue. */
1264 pipelined_receive(&wake_q, info);
1265 spin_unlock(&info->lock);
1266 wake_up_q(&wake_q);
1267 ret = 0;
1268 }
1269 if (ret == 0) {
1270 ret = msg_ptr->m_ts;
1271
1272 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1273 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1274 ret = -EFAULT;
1275 }
1276 free_msg(msg_ptr);
1277 }
1278 out_fput:
1279 fdput(f);
1280 out:
1281 return ret;
1282 }
1283
1284 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1285 size_t, msg_len, unsigned int, msg_prio,
1286 const struct __kernel_timespec __user *, u_abs_timeout)
1287 {
1288 struct timespec64 ts, *p = NULL;
1289 if (u_abs_timeout) {
1290 int res = prepare_timeout(u_abs_timeout, &ts);
1291 if (res)
1292 return res;
1293 p = &ts;
1294 }
1295 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1296 }
1297
1298 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1299 size_t, msg_len, unsigned int __user *, u_msg_prio,
1300 const struct __kernel_timespec __user *, u_abs_timeout)
1301 {
1302 struct timespec64 ts, *p = NULL;
1303 if (u_abs_timeout) {
1304 int res = prepare_timeout(u_abs_timeout, &ts);
1305 if (res)
1306 return res;
1307 p = &ts;
1308 }
1309 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1310 }
1311
1312 /*
1313 * Notes: the case when user wants us to deregister (with NULL as pointer)
1314 * and he isn't currently owner of notification, will be silently discarded.
1315 * It isn't explicitly defined in the POSIX.
1316 */
1317 static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1318 {
1319 int ret;
1320 struct fd f;
1321 struct sock *sock;
1322 struct inode *inode;
1323 struct mqueue_inode_info *info;
1324 struct sk_buff *nc;
1325
1326 audit_mq_notify(mqdes, notification);
1327
1328 nc = NULL;
1329 sock = NULL;
1330 if (notification != NULL) {
1331 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1332 notification->sigev_notify != SIGEV_SIGNAL &&
1333 notification->sigev_notify != SIGEV_THREAD))
1334 return -EINVAL;
1335 if (notification->sigev_notify == SIGEV_SIGNAL &&
1336 !valid_signal(notification->sigev_signo)) {
1337 return -EINVAL;
1338 }
1339 if (notification->sigev_notify == SIGEV_THREAD) {
1340 long timeo;
1341
1342 /* create the notify skb */
1343 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1344 if (!nc)
1345 return -ENOMEM;
1346
1347 if (copy_from_user(nc->data,
1348 notification->sigev_value.sival_ptr,
1349 NOTIFY_COOKIE_LEN)) {
1350 ret = -EFAULT;
1351 goto free_skb;
1352 }
1353
1354 /* TODO: add a header? */
1355 skb_put(nc, NOTIFY_COOKIE_LEN);
1356 /* and attach it to the socket */
1357 retry:
1358 f = fdget(notification->sigev_signo);
1359 if (!f.file) {
1360 ret = -EBADF;
1361 goto out;
1362 }
1363 sock = netlink_getsockbyfilp(f.file);
1364 fdput(f);
1365 if (IS_ERR(sock)) {
1366 ret = PTR_ERR(sock);
1367 goto free_skb;
1368 }
1369
1370 timeo = MAX_SCHEDULE_TIMEOUT;
1371 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1372 if (ret == 1) {
1373 sock = NULL;
1374 goto retry;
1375 }
1376 if (ret)
1377 return ret;
1378 }
1379 }
1380
1381 f = fdget(mqdes);
1382 if (!f.file) {
1383 ret = -EBADF;
1384 goto out;
1385 }
1386
1387 inode = file_inode(f.file);
1388 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1389 ret = -EBADF;
1390 goto out_fput;
1391 }
1392 info = MQUEUE_I(inode);
1393
1394 ret = 0;
1395 spin_lock(&info->lock);
1396 if (notification == NULL) {
1397 if (info->notify_owner == task_tgid(current)) {
1398 remove_notification(info);
1399 inode_set_atime_to_ts(inode,
1400 inode_set_ctime_current(inode));
1401 }
1402 } else if (info->notify_owner != NULL) {
1403 ret = -EBUSY;
1404 } else {
1405 switch (notification->sigev_notify) {
1406 case SIGEV_NONE:
1407 info->notify.sigev_notify = SIGEV_NONE;
1408 break;
1409 case SIGEV_THREAD:
1410 info->notify_sock = sock;
1411 info->notify_cookie = nc;
1412 sock = NULL;
1413 nc = NULL;
1414 info->notify.sigev_notify = SIGEV_THREAD;
1415 break;
1416 case SIGEV_SIGNAL:
1417 info->notify.sigev_signo = notification->sigev_signo;
1418 info->notify.sigev_value = notification->sigev_value;
1419 info->notify.sigev_notify = SIGEV_SIGNAL;
1420 info->notify_self_exec_id = current->self_exec_id;
1421 break;
1422 }
1423
1424 info->notify_owner = get_pid(task_tgid(current));
1425 info->notify_user_ns = get_user_ns(current_user_ns());
1426 inode_set_atime_to_ts(inode, inode_set_ctime_current(inode));
1427 }
1428 spin_unlock(&info->lock);
1429 out_fput:
1430 fdput(f);
1431 out:
1432 if (sock)
1433 netlink_detachskb(sock, nc);
1434 else
1435 free_skb:
1436 dev_kfree_skb(nc);
1437
1438 return ret;
1439 }
1440
1441 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1442 const struct sigevent __user *, u_notification)
1443 {
1444 struct sigevent n, *p = NULL;
1445 if (u_notification) {
1446 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1447 return -EFAULT;
1448 p = &n;
1449 }
1450 return do_mq_notify(mqdes, p);
1451 }
1452
1453 static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1454 {
1455 struct fd f;
1456 struct inode *inode;
1457 struct mqueue_inode_info *info;
1458
1459 if (new && (new->mq_flags & (~O_NONBLOCK)))
1460 return -EINVAL;
1461
1462 f = fdget(mqdes);
1463 if (!f.file)
1464 return -EBADF;
1465
1466 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1467 fdput(f);
1468 return -EBADF;
1469 }
1470
1471 inode = file_inode(f.file);
1472 info = MQUEUE_I(inode);
1473
1474 spin_lock(&info->lock);
1475
1476 if (old) {
1477 *old = info->attr;
1478 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1479 }
1480 if (new) {
1481 audit_mq_getsetattr(mqdes, new);
1482 spin_lock(&f.file->f_lock);
1483 if (new->mq_flags & O_NONBLOCK)
1484 f.file->f_flags |= O_NONBLOCK;
1485 else
1486 f.file->f_flags &= ~O_NONBLOCK;
1487 spin_unlock(&f.file->f_lock);
1488
1489 inode_set_atime_to_ts(inode, inode_set_ctime_current(inode));
1490 }
1491
1492 spin_unlock(&info->lock);
1493 fdput(f);
1494 return 0;
1495 }
1496
1497 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1498 const struct mq_attr __user *, u_mqstat,
1499 struct mq_attr __user *, u_omqstat)
1500 {
1501 int ret;
1502 struct mq_attr mqstat, omqstat;
1503 struct mq_attr *new = NULL, *old = NULL;
1504
1505 if (u_mqstat) {
1506 new = &mqstat;
1507 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1508 return -EFAULT;
1509 }
1510 if (u_omqstat)
1511 old = &omqstat;
1512
1513 ret = do_mq_getsetattr(mqdes, new, old);
1514 if (ret || !old)
1515 return ret;
1516
1517 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1518 return -EFAULT;
1519 return 0;
1520 }
1521
1522 #ifdef CONFIG_COMPAT
1523
1524 struct compat_mq_attr {
1525 compat_long_t mq_flags; /* message queue flags */
1526 compat_long_t mq_maxmsg; /* maximum number of messages */
1527 compat_long_t mq_msgsize; /* maximum message size */
1528 compat_long_t mq_curmsgs; /* number of messages currently queued */
1529 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1530 };
1531
1532 static inline int get_compat_mq_attr(struct mq_attr *attr,
1533 const struct compat_mq_attr __user *uattr)
1534 {
1535 struct compat_mq_attr v;
1536
1537 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1538 return -EFAULT;
1539
1540 memset(attr, 0, sizeof(*attr));
1541 attr->mq_flags = v.mq_flags;
1542 attr->mq_maxmsg = v.mq_maxmsg;
1543 attr->mq_msgsize = v.mq_msgsize;
1544 attr->mq_curmsgs = v.mq_curmsgs;
1545 return 0;
1546 }
1547
1548 static inline int put_compat_mq_attr(const struct mq_attr *attr,
1549 struct compat_mq_attr __user *uattr)
1550 {
1551 struct compat_mq_attr v;
1552
1553 memset(&v, 0, sizeof(v));
1554 v.mq_flags = attr->mq_flags;
1555 v.mq_maxmsg = attr->mq_maxmsg;
1556 v.mq_msgsize = attr->mq_msgsize;
1557 v.mq_curmsgs = attr->mq_curmsgs;
1558 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1559 return -EFAULT;
1560 return 0;
1561 }
1562
1563 COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1564 int, oflag, compat_mode_t, mode,
1565 struct compat_mq_attr __user *, u_attr)
1566 {
1567 struct mq_attr attr, *p = NULL;
1568 if (u_attr && oflag & O_CREAT) {
1569 p = &attr;
1570 if (get_compat_mq_attr(&attr, u_attr))
1571 return -EFAULT;
1572 }
1573 return do_mq_open(u_name, oflag, mode, p);
1574 }
1575
1576 COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1577 const struct compat_sigevent __user *, u_notification)
1578 {
1579 struct sigevent n, *p = NULL;
1580 if (u_notification) {
1581 if (get_compat_sigevent(&n, u_notification))
1582 return -EFAULT;
1583 if (n.sigev_notify == SIGEV_THREAD)
1584 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1585 p = &n;
1586 }
1587 return do_mq_notify(mqdes, p);
1588 }
1589
1590 COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1591 const struct compat_mq_attr __user *, u_mqstat,
1592 struct compat_mq_attr __user *, u_omqstat)
1593 {
1594 int ret;
1595 struct mq_attr mqstat, omqstat;
1596 struct mq_attr *new = NULL, *old = NULL;
1597
1598 if (u_mqstat) {
1599 new = &mqstat;
1600 if (get_compat_mq_attr(new, u_mqstat))
1601 return -EFAULT;
1602 }
1603 if (u_omqstat)
1604 old = &omqstat;
1605
1606 ret = do_mq_getsetattr(mqdes, new, old);
1607 if (ret || !old)
1608 return ret;
1609
1610 if (put_compat_mq_attr(old, u_omqstat))
1611 return -EFAULT;
1612 return 0;
1613 }
1614 #endif
1615
1616 #ifdef CONFIG_COMPAT_32BIT_TIME
1617 static int compat_prepare_timeout(const struct old_timespec32 __user *p,
1618 struct timespec64 *ts)
1619 {
1620 if (get_old_timespec32(ts, p))
1621 return -EFAULT;
1622 if (!timespec64_valid(ts))
1623 return -EINVAL;
1624 return 0;
1625 }
1626
1627 SYSCALL_DEFINE5(mq_timedsend_time32, mqd_t, mqdes,
1628 const char __user *, u_msg_ptr,
1629 unsigned int, msg_len, unsigned int, msg_prio,
1630 const struct old_timespec32 __user *, u_abs_timeout)
1631 {
1632 struct timespec64 ts, *p = NULL;
1633 if (u_abs_timeout) {
1634 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1635 if (res)
1636 return res;
1637 p = &ts;
1638 }
1639 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1640 }
1641
1642 SYSCALL_DEFINE5(mq_timedreceive_time32, mqd_t, mqdes,
1643 char __user *, u_msg_ptr,
1644 unsigned int, msg_len, unsigned int __user *, u_msg_prio,
1645 const struct old_timespec32 __user *, u_abs_timeout)
1646 {
1647 struct timespec64 ts, *p = NULL;
1648 if (u_abs_timeout) {
1649 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1650 if (res)
1651 return res;
1652 p = &ts;
1653 }
1654 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1655 }
1656 #endif
1657
1658 static const struct inode_operations mqueue_dir_inode_operations = {
1659 .lookup = simple_lookup,
1660 .create = mqueue_create,
1661 .unlink = mqueue_unlink,
1662 };
1663
1664 static const struct file_operations mqueue_file_operations = {
1665 .flush = mqueue_flush_file,
1666 .poll = mqueue_poll_file,
1667 .read = mqueue_read_file,
1668 .llseek = default_llseek,
1669 };
1670
1671 static const struct super_operations mqueue_super_ops = {
1672 .alloc_inode = mqueue_alloc_inode,
1673 .free_inode = mqueue_free_inode,
1674 .evict_inode = mqueue_evict_inode,
1675 .statfs = simple_statfs,
1676 };
1677
1678 static const struct fs_context_operations mqueue_fs_context_ops = {
1679 .free = mqueue_fs_context_free,
1680 .get_tree = mqueue_get_tree,
1681 };
1682
1683 static struct file_system_type mqueue_fs_type = {
1684 .name = "mqueue",
1685 .init_fs_context = mqueue_init_fs_context,
1686 .kill_sb = kill_litter_super,
1687 .fs_flags = FS_USERNS_MOUNT,
1688 };
1689
1690 int mq_init_ns(struct ipc_namespace *ns)
1691 {
1692 struct vfsmount *m;
1693
1694 ns->mq_queues_count = 0;
1695 ns->mq_queues_max = DFLT_QUEUESMAX;
1696 ns->mq_msg_max = DFLT_MSGMAX;
1697 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1698 ns->mq_msg_default = DFLT_MSG;
1699 ns->mq_msgsize_default = DFLT_MSGSIZE;
1700
1701 m = mq_create_mount(ns);
1702 if (IS_ERR(m))
1703 return PTR_ERR(m);
1704 ns->mq_mnt = m;
1705 return 0;
1706 }
1707
1708 void mq_clear_sbinfo(struct ipc_namespace *ns)
1709 {
1710 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1711 }
1712
1713 static int __init init_mqueue_fs(void)
1714 {
1715 int error;
1716
1717 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1718 sizeof(struct mqueue_inode_info), 0,
1719 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1720 if (mqueue_inode_cachep == NULL)
1721 return -ENOMEM;
1722
1723 if (!setup_mq_sysctls(&init_ipc_ns)) {
1724 pr_warn("sysctl registration failed\n");
1725 error = -ENOMEM;
1726 goto out_kmem;
1727 }
1728
1729 error = register_filesystem(&mqueue_fs_type);
1730 if (error)
1731 goto out_sysctl;
1732
1733 spin_lock_init(&mq_lock);
1734
1735 error = mq_init_ns(&init_ipc_ns);
1736 if (error)
1737 goto out_filesystem;
1738
1739 return 0;
1740
1741 out_filesystem:
1742 unregister_filesystem(&mqueue_fs_type);
1743 out_sysctl:
1744 retire_mq_sysctls(&init_ipc_ns);
1745 out_kmem:
1746 kmem_cache_destroy(mqueue_inode_cachep);
1747 return error;
1748 }
1749
1750 device_initcall(init_mqueue_fs);
1751
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