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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/vmalloc.h>
28#include <linux/netlink.h>
29#include <linux/syscalls.h>
30#include <linux/audit.h>
31#include <linux/signal.h>
32#include <linux/mutex.h>
33#include <linux/nsproxy.h>
34#include <linux/pid.h>
35#include <linux/ipc_namespace.h>
36#include <linux/user_namespace.h>
37#include <linux/slab.h>
38#include <linux/sched/wake_q.h>
39#include <linux/sched/signal.h>
40#include <linux/sched/user.h>
41
42#include <net/sock.h>
43#include "util.h"
44
45#define MQUEUE_MAGIC 0x19800202
46#define DIRENT_SIZE 20
47#define FILENT_SIZE 80
48
49#define SEND 0
50#define RECV 1
51
52#define STATE_NONE 0
53#define STATE_READY 1
54
55struct posix_msg_tree_node {
56 struct rb_node rb_node;
57 struct list_head msg_list;
58 int priority;
59};
60
61struct ext_wait_queue { /* queue of sleeping tasks */
62 struct task_struct *task;
63 struct list_head list;
64 struct msg_msg *msg; /* ptr of loaded message */
65 int state; /* one of STATE_* values */
66};
67
68struct mqueue_inode_info {
69 spinlock_t lock;
70 struct inode vfs_inode;
71 wait_queue_head_t wait_q;
72
73 struct rb_root msg_tree;
74 struct posix_msg_tree_node *node_cache;
75 struct mq_attr attr;
76
77 struct sigevent notify;
78 struct pid *notify_owner;
79 struct user_namespace *notify_user_ns;
80 struct user_struct *user; /* user who created, for accounting */
81 struct sock *notify_sock;
82 struct sk_buff *notify_cookie;
83
84 /* for tasks waiting for free space and messages, respectively */
85 struct ext_wait_queue e_wait_q[2];
86
87 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
88};
89
90static const struct inode_operations mqueue_dir_inode_operations;
91static const struct file_operations mqueue_file_operations;
92static const struct super_operations mqueue_super_ops;
93static void remove_notification(struct mqueue_inode_info *info);
94
95static struct kmem_cache *mqueue_inode_cachep;
96
97static struct ctl_table_header *mq_sysctl_table;
98
99static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
100{
101 return container_of(inode, struct mqueue_inode_info, vfs_inode);
102}
103
104/*
105 * This routine should be called with the mq_lock held.
106 */
107static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
108{
109 return get_ipc_ns(inode->i_sb->s_fs_info);
110}
111
112static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
113{
114 struct ipc_namespace *ns;
115
116 spin_lock(&mq_lock);
117 ns = __get_ns_from_inode(inode);
118 spin_unlock(&mq_lock);
119 return ns;
120}
121
122/* Auxiliary functions to manipulate messages' list */
123static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
124{
125 struct rb_node **p, *parent = NULL;
126 struct posix_msg_tree_node *leaf;
127
128 p = &info->msg_tree.rb_node;
129 while (*p) {
130 parent = *p;
131 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
132
133 if (likely(leaf->priority == msg->m_type))
134 goto insert_msg;
135 else if (msg->m_type < leaf->priority)
136 p = &(*p)->rb_left;
137 else
138 p = &(*p)->rb_right;
139 }
140 if (info->node_cache) {
141 leaf = info->node_cache;
142 info->node_cache = NULL;
143 } else {
144 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
145 if (!leaf)
146 return -ENOMEM;
147 INIT_LIST_HEAD(&leaf->msg_list);
148 }
149 leaf->priority = msg->m_type;
150 rb_link_node(&leaf->rb_node, parent, p);
151 rb_insert_color(&leaf->rb_node, &info->msg_tree);
152insert_msg:
153 info->attr.mq_curmsgs++;
154 info->qsize += msg->m_ts;
155 list_add_tail(&msg->m_list, &leaf->msg_list);
156 return 0;
157}
158
159static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
160{
161 struct rb_node **p, *parent = NULL;
162 struct posix_msg_tree_node *leaf;
163 struct msg_msg *msg;
164
165try_again:
166 p = &info->msg_tree.rb_node;
167 while (*p) {
168 parent = *p;
169 /*
170 * During insert, low priorities go to the left and high to the
171 * right. On receive, we want the highest priorities first, so
172 * walk all the way to the right.
173 */
174 p = &(*p)->rb_right;
175 }
176 if (!parent) {
177 if (info->attr.mq_curmsgs) {
178 pr_warn_once("Inconsistency in POSIX message queue, "
179 "no tree element, but supposedly messages "
180 "should exist!\n");
181 info->attr.mq_curmsgs = 0;
182 }
183 return NULL;
184 }
185 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
186 if (unlikely(list_empty(&leaf->msg_list))) {
187 pr_warn_once("Inconsistency in POSIX message queue, "
188 "empty leaf node but we haven't implemented "
189 "lazy leaf delete!\n");
190 rb_erase(&leaf->rb_node, &info->msg_tree);
191 if (info->node_cache) {
192 kfree(leaf);
193 } else {
194 info->node_cache = leaf;
195 }
196 goto try_again;
197 } else {
198 msg = list_first_entry(&leaf->msg_list,
199 struct msg_msg, m_list);
200 list_del(&msg->m_list);
201 if (list_empty(&leaf->msg_list)) {
202 rb_erase(&leaf->rb_node, &info->msg_tree);
203 if (info->node_cache) {
204 kfree(leaf);
205 } else {
206 info->node_cache = leaf;
207 }
208 }
209 }
210 info->attr.mq_curmsgs--;
211 info->qsize -= msg->m_ts;
212 return msg;
213}
214
215static struct inode *mqueue_get_inode(struct super_block *sb,
216 struct ipc_namespace *ipc_ns, umode_t mode,
217 struct mq_attr *attr)
218{
219 struct user_struct *u = current_user();
220 struct inode *inode;
221 int ret = -ENOMEM;
222
223 inode = new_inode(sb);
224 if (!inode)
225 goto err;
226
227 inode->i_ino = get_next_ino();
228 inode->i_mode = mode;
229 inode->i_uid = current_fsuid();
230 inode->i_gid = current_fsgid();
231 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
232
233 if (S_ISREG(mode)) {
234 struct mqueue_inode_info *info;
235 unsigned long mq_bytes, mq_treesize;
236
237 inode->i_fop = &mqueue_file_operations;
238 inode->i_size = FILENT_SIZE;
239 /* mqueue specific info */
240 info = MQUEUE_I(inode);
241 spin_lock_init(&info->lock);
242 init_waitqueue_head(&info->wait_q);
243 INIT_LIST_HEAD(&info->e_wait_q[0].list);
244 INIT_LIST_HEAD(&info->e_wait_q[1].list);
245 info->notify_owner = NULL;
246 info->notify_user_ns = NULL;
247 info->qsize = 0;
248 info->user = NULL; /* set when all is ok */
249 info->msg_tree = RB_ROOT;
250 info->node_cache = NULL;
251 memset(&info->attr, 0, sizeof(info->attr));
252 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
253 ipc_ns->mq_msg_default);
254 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
255 ipc_ns->mq_msgsize_default);
256 if (attr) {
257 info->attr.mq_maxmsg = attr->mq_maxmsg;
258 info->attr.mq_msgsize = attr->mq_msgsize;
259 }
260 /*
261 * We used to allocate a static array of pointers and account
262 * the size of that array as well as one msg_msg struct per
263 * possible message into the queue size. That's no longer
264 * accurate as the queue is now an rbtree and will grow and
265 * shrink depending on usage patterns. We can, however, still
266 * account one msg_msg struct per message, but the nodes are
267 * allocated depending on priority usage, and most programs
268 * only use one, or a handful, of priorities. However, since
269 * this is pinned memory, we need to assume worst case, so
270 * that means the min(mq_maxmsg, max_priorities) * struct
271 * posix_msg_tree_node.
272 */
273
274 ret = -EINVAL;
275 if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
276 goto out_inode;
277 if (capable(CAP_SYS_RESOURCE)) {
278 if (info->attr.mq_maxmsg > HARD_MSGMAX ||
279 info->attr.mq_msgsize > HARD_MSGSIZEMAX)
280 goto out_inode;
281 } else {
282 if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
283 info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
284 goto out_inode;
285 }
286 ret = -EOVERFLOW;
287 /* check for overflow */
288 if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
289 goto out_inode;
290 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
291 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
292 sizeof(struct posix_msg_tree_node);
293 mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
294 if (mq_bytes + mq_treesize < mq_bytes)
295 goto out_inode;
296 mq_bytes += mq_treesize;
297 spin_lock(&mq_lock);
298 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
299 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
300 spin_unlock(&mq_lock);
301 /* mqueue_evict_inode() releases info->messages */
302 ret = -EMFILE;
303 goto out_inode;
304 }
305 u->mq_bytes += mq_bytes;
306 spin_unlock(&mq_lock);
307
308 /* all is ok */
309 info->user = get_uid(u);
310 } else if (S_ISDIR(mode)) {
311 inc_nlink(inode);
312 /* Some things misbehave if size == 0 on a directory */
313 inode->i_size = 2 * DIRENT_SIZE;
314 inode->i_op = &mqueue_dir_inode_operations;
315 inode->i_fop = &simple_dir_operations;
316 }
317
318 return inode;
319out_inode:
320 iput(inode);
321err:
322 return ERR_PTR(ret);
323}
324
325static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
326{
327 struct inode *inode;
328 struct ipc_namespace *ns = sb->s_fs_info;
329
330 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
331 sb->s_blocksize = PAGE_SIZE;
332 sb->s_blocksize_bits = PAGE_SHIFT;
333 sb->s_magic = MQUEUE_MAGIC;
334 sb->s_op = &mqueue_super_ops;
335
336 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
337 if (IS_ERR(inode))
338 return PTR_ERR(inode);
339
340 sb->s_root = d_make_root(inode);
341 if (!sb->s_root)
342 return -ENOMEM;
343 return 0;
344}
345
346static struct dentry *mqueue_mount(struct file_system_type *fs_type,
347 int flags, const char *dev_name,
348 void *data)
349{
350 struct ipc_namespace *ns;
351 if (flags & SB_KERNMOUNT) {
352 ns = data;
353 data = NULL;
354 } else {
355 ns = current->nsproxy->ipc_ns;
356 }
357 return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super);
358}
359
360static void init_once(void *foo)
361{
362 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
363
364 inode_init_once(&p->vfs_inode);
365}
366
367static struct inode *mqueue_alloc_inode(struct super_block *sb)
368{
369 struct mqueue_inode_info *ei;
370
371 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
372 if (!ei)
373 return NULL;
374 return &ei->vfs_inode;
375}
376
377static void mqueue_i_callback(struct rcu_head *head)
378{
379 struct inode *inode = container_of(head, struct inode, i_rcu);
380 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
381}
382
383static void mqueue_destroy_inode(struct inode *inode)
384{
385 call_rcu(&inode->i_rcu, mqueue_i_callback);
386}
387
388static void mqueue_evict_inode(struct inode *inode)
389{
390 struct mqueue_inode_info *info;
391 struct user_struct *user;
392 unsigned long mq_bytes, mq_treesize;
393 struct ipc_namespace *ipc_ns;
394 struct msg_msg *msg;
395
396 clear_inode(inode);
397
398 if (S_ISDIR(inode->i_mode))
399 return;
400
401 ipc_ns = get_ns_from_inode(inode);
402 info = MQUEUE_I(inode);
403 spin_lock(&info->lock);
404 while ((msg = msg_get(info)) != NULL)
405 free_msg(msg);
406 kfree(info->node_cache);
407 spin_unlock(&info->lock);
408
409 /* Total amount of bytes accounted for the mqueue */
410 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
411 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
412 sizeof(struct posix_msg_tree_node);
413
414 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
415 info->attr.mq_msgsize);
416
417 user = info->user;
418 if (user) {
419 spin_lock(&mq_lock);
420 user->mq_bytes -= mq_bytes;
421 /*
422 * get_ns_from_inode() ensures that the
423 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
424 * to which we now hold a reference, or it is NULL.
425 * We can't put it here under mq_lock, though.
426 */
427 if (ipc_ns)
428 ipc_ns->mq_queues_count--;
429 spin_unlock(&mq_lock);
430 free_uid(user);
431 }
432 if (ipc_ns)
433 put_ipc_ns(ipc_ns);
434}
435
436static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
437{
438 struct inode *dir = dentry->d_parent->d_inode;
439 struct inode *inode;
440 struct mq_attr *attr = arg;
441 int error;
442 struct ipc_namespace *ipc_ns;
443
444 spin_lock(&mq_lock);
445 ipc_ns = __get_ns_from_inode(dir);
446 if (!ipc_ns) {
447 error = -EACCES;
448 goto out_unlock;
449 }
450
451 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
452 !capable(CAP_SYS_RESOURCE)) {
453 error = -ENOSPC;
454 goto out_unlock;
455 }
456 ipc_ns->mq_queues_count++;
457 spin_unlock(&mq_lock);
458
459 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
460 if (IS_ERR(inode)) {
461 error = PTR_ERR(inode);
462 spin_lock(&mq_lock);
463 ipc_ns->mq_queues_count--;
464 goto out_unlock;
465 }
466
467 put_ipc_ns(ipc_ns);
468 dir->i_size += DIRENT_SIZE;
469 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
470
471 d_instantiate(dentry, inode);
472 dget(dentry);
473 return 0;
474out_unlock:
475 spin_unlock(&mq_lock);
476 if (ipc_ns)
477 put_ipc_ns(ipc_ns);
478 return error;
479}
480
481static int mqueue_create(struct inode *dir, struct dentry *dentry,
482 umode_t mode, bool excl)
483{
484 return mqueue_create_attr(dentry, mode, NULL);
485}
486
487static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
488{
489 struct inode *inode = d_inode(dentry);
490
491 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
492 dir->i_size -= DIRENT_SIZE;
493 drop_nlink(inode);
494 dput(dentry);
495 return 0;
496}
497
498/*
499* This is routine for system read from queue file.
500* To avoid mess with doing here some sort of mq_receive we allow
501* to read only queue size & notification info (the only values
502* that are interesting from user point of view and aren't accessible
503* through std routines)
504*/
505static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
506 size_t count, loff_t *off)
507{
508 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
509 char buffer[FILENT_SIZE];
510 ssize_t ret;
511
512 spin_lock(&info->lock);
513 snprintf(buffer, sizeof(buffer),
514 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
515 info->qsize,
516 info->notify_owner ? info->notify.sigev_notify : 0,
517 (info->notify_owner &&
518 info->notify.sigev_notify == SIGEV_SIGNAL) ?
519 info->notify.sigev_signo : 0,
520 pid_vnr(info->notify_owner));
521 spin_unlock(&info->lock);
522 buffer[sizeof(buffer)-1] = '\0';
523
524 ret = simple_read_from_buffer(u_data, count, off, buffer,
525 strlen(buffer));
526 if (ret <= 0)
527 return ret;
528
529 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
530 return ret;
531}
532
533static int mqueue_flush_file(struct file *filp, fl_owner_t id)
534{
535 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
536
537 spin_lock(&info->lock);
538 if (task_tgid(current) == info->notify_owner)
539 remove_notification(info);
540
541 spin_unlock(&info->lock);
542 return 0;
543}
544
545static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
546{
547 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
548 __poll_t retval = 0;
549
550 poll_wait(filp, &info->wait_q, poll_tab);
551
552 spin_lock(&info->lock);
553 if (info->attr.mq_curmsgs)
554 retval = EPOLLIN | EPOLLRDNORM;
555
556 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
557 retval |= EPOLLOUT | EPOLLWRNORM;
558 spin_unlock(&info->lock);
559
560 return retval;
561}
562
563/* Adds current to info->e_wait_q[sr] before element with smaller prio */
564static void wq_add(struct mqueue_inode_info *info, int sr,
565 struct ext_wait_queue *ewp)
566{
567 struct ext_wait_queue *walk;
568
569 ewp->task = current;
570
571 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
572 if (walk->task->prio <= current->prio) {
573 list_add_tail(&ewp->list, &walk->list);
574 return;
575 }
576 }
577 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
578}
579
580/*
581 * Puts current task to sleep. Caller must hold queue lock. After return
582 * lock isn't held.
583 * sr: SEND or RECV
584 */
585static int wq_sleep(struct mqueue_inode_info *info, int sr,
586 ktime_t *timeout, struct ext_wait_queue *ewp)
587 __releases(&info->lock)
588{
589 int retval;
590 signed long time;
591
592 wq_add(info, sr, ewp);
593
594 for (;;) {
595 __set_current_state(TASK_INTERRUPTIBLE);
596
597 spin_unlock(&info->lock);
598 time = schedule_hrtimeout_range_clock(timeout, 0,
599 HRTIMER_MODE_ABS, CLOCK_REALTIME);
600
601 if (ewp->state == STATE_READY) {
602 retval = 0;
603 goto out;
604 }
605 spin_lock(&info->lock);
606 if (ewp->state == STATE_READY) {
607 retval = 0;
608 goto out_unlock;
609 }
610 if (signal_pending(current)) {
611 retval = -ERESTARTSYS;
612 break;
613 }
614 if (time == 0) {
615 retval = -ETIMEDOUT;
616 break;
617 }
618 }
619 list_del(&ewp->list);
620out_unlock:
621 spin_unlock(&info->lock);
622out:
623 return retval;
624}
625
626/*
627 * Returns waiting task that should be serviced first or NULL if none exists
628 */
629static struct ext_wait_queue *wq_get_first_waiter(
630 struct mqueue_inode_info *info, int sr)
631{
632 struct list_head *ptr;
633
634 ptr = info->e_wait_q[sr].list.prev;
635 if (ptr == &info->e_wait_q[sr].list)
636 return NULL;
637 return list_entry(ptr, struct ext_wait_queue, list);
638}
639
640
641static inline void set_cookie(struct sk_buff *skb, char code)
642{
643 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
644}
645
646/*
647 * The next function is only to split too long sys_mq_timedsend
648 */
649static void __do_notify(struct mqueue_inode_info *info)
650{
651 /* notification
652 * invoked when there is registered process and there isn't process
653 * waiting synchronously for message AND state of queue changed from
654 * empty to not empty. Here we are sure that no one is waiting
655 * synchronously. */
656 if (info->notify_owner &&
657 info->attr.mq_curmsgs == 1) {
658 struct siginfo sig_i;
659 switch (info->notify.sigev_notify) {
660 case SIGEV_NONE:
661 break;
662 case SIGEV_SIGNAL:
663 /* sends signal */
664
665 clear_siginfo(&sig_i);
666 sig_i.si_signo = info->notify.sigev_signo;
667 sig_i.si_errno = 0;
668 sig_i.si_code = SI_MESGQ;
669 sig_i.si_value = info->notify.sigev_value;
670 /* map current pid/uid into info->owner's namespaces */
671 rcu_read_lock();
672 sig_i.si_pid = task_tgid_nr_ns(current,
673 ns_of_pid(info->notify_owner));
674 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
675 rcu_read_unlock();
676
677 kill_pid_info(info->notify.sigev_signo,
678 &sig_i, info->notify_owner);
679 break;
680 case SIGEV_THREAD:
681 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
682 netlink_sendskb(info->notify_sock, info->notify_cookie);
683 break;
684 }
685 /* after notification unregisters process */
686 put_pid(info->notify_owner);
687 put_user_ns(info->notify_user_ns);
688 info->notify_owner = NULL;
689 info->notify_user_ns = NULL;
690 }
691 wake_up(&info->wait_q);
692}
693
694static int prepare_timeout(const struct timespec __user *u_abs_timeout,
695 struct timespec64 *ts)
696{
697 if (get_timespec64(ts, u_abs_timeout))
698 return -EFAULT;
699 if (!timespec64_valid(ts))
700 return -EINVAL;
701 return 0;
702}
703
704static void remove_notification(struct mqueue_inode_info *info)
705{
706 if (info->notify_owner != NULL &&
707 info->notify.sigev_notify == SIGEV_THREAD) {
708 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
709 netlink_sendskb(info->notify_sock, info->notify_cookie);
710 }
711 put_pid(info->notify_owner);
712 put_user_ns(info->notify_user_ns);
713 info->notify_owner = NULL;
714 info->notify_user_ns = NULL;
715}
716
717static int prepare_open(struct dentry *dentry, int oflag, int ro,
718 umode_t mode, struct filename *name,
719 struct mq_attr *attr)
720{
721 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
722 MAY_READ | MAY_WRITE };
723 int acc;
724
725 if (d_really_is_negative(dentry)) {
726 if (!(oflag & O_CREAT))
727 return -ENOENT;
728 if (ro)
729 return ro;
730 audit_inode_parent_hidden(name, dentry->d_parent);
731 return vfs_mkobj(dentry, mode & ~current_umask(),
732 mqueue_create_attr, attr);
733 }
734 /* it already existed */
735 audit_inode(name, dentry, 0);
736 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
737 return -EEXIST;
738 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
739 return -EINVAL;
740 acc = oflag2acc[oflag & O_ACCMODE];
741 return inode_permission(d_inode(dentry), acc);
742}
743
744static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
745 struct mq_attr *attr)
746{
747 struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
748 struct dentry *root = mnt->mnt_root;
749 struct filename *name;
750 struct path path;
751 int fd, error;
752 int ro;
753
754 audit_mq_open(oflag, mode, attr);
755
756 if (IS_ERR(name = getname(u_name)))
757 return PTR_ERR(name);
758
759 fd = get_unused_fd_flags(O_CLOEXEC);
760 if (fd < 0)
761 goto out_putname;
762
763 ro = mnt_want_write(mnt); /* we'll drop it in any case */
764 inode_lock(d_inode(root));
765 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
766 if (IS_ERR(path.dentry)) {
767 error = PTR_ERR(path.dentry);
768 goto out_putfd;
769 }
770 path.mnt = mntget(mnt);
771 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
772 if (!error) {
773 struct file *file = dentry_open(&path, oflag, current_cred());
774 if (!IS_ERR(file))
775 fd_install(fd, file);
776 else
777 error = PTR_ERR(file);
778 }
779 path_put(&path);
780out_putfd:
781 if (error) {
782 put_unused_fd(fd);
783 fd = error;
784 }
785 inode_unlock(d_inode(root));
786 if (!ro)
787 mnt_drop_write(mnt);
788out_putname:
789 putname(name);
790 return fd;
791}
792
793SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
794 struct mq_attr __user *, u_attr)
795{
796 struct mq_attr attr;
797 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
798 return -EFAULT;
799
800 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
801}
802
803SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
804{
805 int err;
806 struct filename *name;
807 struct dentry *dentry;
808 struct inode *inode = NULL;
809 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
810 struct vfsmount *mnt = ipc_ns->mq_mnt;
811
812 name = getname(u_name);
813 if (IS_ERR(name))
814 return PTR_ERR(name);
815
816 audit_inode_parent_hidden(name, mnt->mnt_root);
817 err = mnt_want_write(mnt);
818 if (err)
819 goto out_name;
820 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
821 dentry = lookup_one_len(name->name, mnt->mnt_root,
822 strlen(name->name));
823 if (IS_ERR(dentry)) {
824 err = PTR_ERR(dentry);
825 goto out_unlock;
826 }
827
828 inode = d_inode(dentry);
829 if (!inode) {
830 err = -ENOENT;
831 } else {
832 ihold(inode);
833 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
834 }
835 dput(dentry);
836
837out_unlock:
838 inode_unlock(d_inode(mnt->mnt_root));
839 if (inode)
840 iput(inode);
841 mnt_drop_write(mnt);
842out_name:
843 putname(name);
844
845 return err;
846}
847
848/* Pipelined send and receive functions.
849 *
850 * If a receiver finds no waiting message, then it registers itself in the
851 * list of waiting receivers. A sender checks that list before adding the new
852 * message into the message array. If there is a waiting receiver, then it
853 * bypasses the message array and directly hands the message over to the
854 * receiver. The receiver accepts the message and returns without grabbing the
855 * queue spinlock:
856 *
857 * - Set pointer to message.
858 * - Queue the receiver task for later wakeup (without the info->lock).
859 * - Update its state to STATE_READY. Now the receiver can continue.
860 * - Wake up the process after the lock is dropped. Should the process wake up
861 * before this wakeup (due to a timeout or a signal) it will either see
862 * STATE_READY and continue or acquire the lock to check the state again.
863 *
864 * The same algorithm is used for senders.
865 */
866
867/* pipelined_send() - send a message directly to the task waiting in
868 * sys_mq_timedreceive() (without inserting message into a queue).
869 */
870static inline void pipelined_send(struct wake_q_head *wake_q,
871 struct mqueue_inode_info *info,
872 struct msg_msg *message,
873 struct ext_wait_queue *receiver)
874{
875 receiver->msg = message;
876 list_del(&receiver->list);
877 wake_q_add(wake_q, receiver->task);
878 /*
879 * Rely on the implicit cmpxchg barrier from wake_q_add such
880 * that we can ensure that updating receiver->state is the last
881 * write operation: As once set, the receiver can continue,
882 * and if we don't have the reference count from the wake_q,
883 * yet, at that point we can later have a use-after-free
884 * condition and bogus wakeup.
885 */
886 receiver->state = STATE_READY;
887}
888
889/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
890 * gets its message and put to the queue (we have one free place for sure). */
891static inline void pipelined_receive(struct wake_q_head *wake_q,
892 struct mqueue_inode_info *info)
893{
894 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
895
896 if (!sender) {
897 /* for poll */
898 wake_up_interruptible(&info->wait_q);
899 return;
900 }
901 if (msg_insert(sender->msg, info))
902 return;
903
904 list_del(&sender->list);
905 wake_q_add(wake_q, sender->task);
906 sender->state = STATE_READY;
907}
908
909static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
910 size_t msg_len, unsigned int msg_prio,
911 struct timespec64 *ts)
912{
913 struct fd f;
914 struct inode *inode;
915 struct ext_wait_queue wait;
916 struct ext_wait_queue *receiver;
917 struct msg_msg *msg_ptr;
918 struct mqueue_inode_info *info;
919 ktime_t expires, *timeout = NULL;
920 struct posix_msg_tree_node *new_leaf = NULL;
921 int ret = 0;
922 DEFINE_WAKE_Q(wake_q);
923
924 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
925 return -EINVAL;
926
927 if (ts) {
928 expires = timespec64_to_ktime(*ts);
929 timeout = &expires;
930 }
931
932 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
933
934 f = fdget(mqdes);
935 if (unlikely(!f.file)) {
936 ret = -EBADF;
937 goto out;
938 }
939
940 inode = file_inode(f.file);
941 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
942 ret = -EBADF;
943 goto out_fput;
944 }
945 info = MQUEUE_I(inode);
946 audit_file(f.file);
947
948 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
949 ret = -EBADF;
950 goto out_fput;
951 }
952
953 if (unlikely(msg_len > info->attr.mq_msgsize)) {
954 ret = -EMSGSIZE;
955 goto out_fput;
956 }
957
958 /* First try to allocate memory, before doing anything with
959 * existing queues. */
960 msg_ptr = load_msg(u_msg_ptr, msg_len);
961 if (IS_ERR(msg_ptr)) {
962 ret = PTR_ERR(msg_ptr);
963 goto out_fput;
964 }
965 msg_ptr->m_ts = msg_len;
966 msg_ptr->m_type = msg_prio;
967
968 /*
969 * msg_insert really wants us to have a valid, spare node struct so
970 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
971 * fall back to that if necessary.
972 */
973 if (!info->node_cache)
974 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
975
976 spin_lock(&info->lock);
977
978 if (!info->node_cache && new_leaf) {
979 /* Save our speculative allocation into the cache */
980 INIT_LIST_HEAD(&new_leaf->msg_list);
981 info->node_cache = new_leaf;
982 new_leaf = NULL;
983 } else {
984 kfree(new_leaf);
985 }
986
987 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
988 if (f.file->f_flags & O_NONBLOCK) {
989 ret = -EAGAIN;
990 } else {
991 wait.task = current;
992 wait.msg = (void *) msg_ptr;
993 wait.state = STATE_NONE;
994 ret = wq_sleep(info, SEND, timeout, &wait);
995 /*
996 * wq_sleep must be called with info->lock held, and
997 * returns with the lock released
998 */
999 goto out_free;
1000 }
1001 } else {
1002 receiver = wq_get_first_waiter(info, RECV);
1003 if (receiver) {
1004 pipelined_send(&wake_q, info, msg_ptr, receiver);
1005 } else {
1006 /* adds message to the queue */
1007 ret = msg_insert(msg_ptr, info);
1008 if (ret)
1009 goto out_unlock;
1010 __do_notify(info);
1011 }
1012 inode->i_atime = inode->i_mtime = inode->i_ctime =
1013 current_time(inode);
1014 }
1015out_unlock:
1016 spin_unlock(&info->lock);
1017 wake_up_q(&wake_q);
1018out_free:
1019 if (ret)
1020 free_msg(msg_ptr);
1021out_fput:
1022 fdput(f);
1023out:
1024 return ret;
1025}
1026
1027static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1028 size_t msg_len, unsigned int __user *u_msg_prio,
1029 struct timespec64 *ts)
1030{
1031 ssize_t ret;
1032 struct msg_msg *msg_ptr;
1033 struct fd f;
1034 struct inode *inode;
1035 struct mqueue_inode_info *info;
1036 struct ext_wait_queue wait;
1037 ktime_t expires, *timeout = NULL;
1038 struct posix_msg_tree_node *new_leaf = NULL;
1039
1040 if (ts) {
1041 expires = timespec64_to_ktime(*ts);
1042 timeout = &expires;
1043 }
1044
1045 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1046
1047 f = fdget(mqdes);
1048 if (unlikely(!f.file)) {
1049 ret = -EBADF;
1050 goto out;
1051 }
1052
1053 inode = file_inode(f.file);
1054 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1055 ret = -EBADF;
1056 goto out_fput;
1057 }
1058 info = MQUEUE_I(inode);
1059 audit_file(f.file);
1060
1061 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1062 ret = -EBADF;
1063 goto out_fput;
1064 }
1065
1066 /* checks if buffer is big enough */
1067 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1068 ret = -EMSGSIZE;
1069 goto out_fput;
1070 }
1071
1072 /*
1073 * msg_insert really wants us to have a valid, spare node struct so
1074 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1075 * fall back to that if necessary.
1076 */
1077 if (!info->node_cache)
1078 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1079
1080 spin_lock(&info->lock);
1081
1082 if (!info->node_cache && new_leaf) {
1083 /* Save our speculative allocation into the cache */
1084 INIT_LIST_HEAD(&new_leaf->msg_list);
1085 info->node_cache = new_leaf;
1086 } else {
1087 kfree(new_leaf);
1088 }
1089
1090 if (info->attr.mq_curmsgs == 0) {
1091 if (f.file->f_flags & O_NONBLOCK) {
1092 spin_unlock(&info->lock);
1093 ret = -EAGAIN;
1094 } else {
1095 wait.task = current;
1096 wait.state = STATE_NONE;
1097 ret = wq_sleep(info, RECV, timeout, &wait);
1098 msg_ptr = wait.msg;
1099 }
1100 } else {
1101 DEFINE_WAKE_Q(wake_q);
1102
1103 msg_ptr = msg_get(info);
1104
1105 inode->i_atime = inode->i_mtime = inode->i_ctime =
1106 current_time(inode);
1107
1108 /* There is now free space in queue. */
1109 pipelined_receive(&wake_q, info);
1110 spin_unlock(&info->lock);
1111 wake_up_q(&wake_q);
1112 ret = 0;
1113 }
1114 if (ret == 0) {
1115 ret = msg_ptr->m_ts;
1116
1117 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1118 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1119 ret = -EFAULT;
1120 }
1121 free_msg(msg_ptr);
1122 }
1123out_fput:
1124 fdput(f);
1125out:
1126 return ret;
1127}
1128
1129SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1130 size_t, msg_len, unsigned int, msg_prio,
1131 const struct timespec __user *, u_abs_timeout)
1132{
1133 struct timespec64 ts, *p = NULL;
1134 if (u_abs_timeout) {
1135 int res = prepare_timeout(u_abs_timeout, &ts);
1136 if (res)
1137 return res;
1138 p = &ts;
1139 }
1140 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1141}
1142
1143SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1144 size_t, msg_len, unsigned int __user *, u_msg_prio,
1145 const struct timespec __user *, u_abs_timeout)
1146{
1147 struct timespec64 ts, *p = NULL;
1148 if (u_abs_timeout) {
1149 int res = prepare_timeout(u_abs_timeout, &ts);
1150 if (res)
1151 return res;
1152 p = &ts;
1153 }
1154 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1155}
1156
1157/*
1158 * Notes: the case when user wants us to deregister (with NULL as pointer)
1159 * and he isn't currently owner of notification, will be silently discarded.
1160 * It isn't explicitly defined in the POSIX.
1161 */
1162static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1163{
1164 int ret;
1165 struct fd f;
1166 struct sock *sock;
1167 struct inode *inode;
1168 struct mqueue_inode_info *info;
1169 struct sk_buff *nc;
1170
1171 audit_mq_notify(mqdes, notification);
1172
1173 nc = NULL;
1174 sock = NULL;
1175 if (notification != NULL) {
1176 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1177 notification->sigev_notify != SIGEV_SIGNAL &&
1178 notification->sigev_notify != SIGEV_THREAD))
1179 return -EINVAL;
1180 if (notification->sigev_notify == SIGEV_SIGNAL &&
1181 !valid_signal(notification->sigev_signo)) {
1182 return -EINVAL;
1183 }
1184 if (notification->sigev_notify == SIGEV_THREAD) {
1185 long timeo;
1186
1187 /* create the notify skb */
1188 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1189 if (!nc) {
1190 ret = -ENOMEM;
1191 goto out;
1192 }
1193 if (copy_from_user(nc->data,
1194 notification->sigev_value.sival_ptr,
1195 NOTIFY_COOKIE_LEN)) {
1196 ret = -EFAULT;
1197 goto out;
1198 }
1199
1200 /* TODO: add a header? */
1201 skb_put(nc, NOTIFY_COOKIE_LEN);
1202 /* and attach it to the socket */
1203retry:
1204 f = fdget(notification->sigev_signo);
1205 if (!f.file) {
1206 ret = -EBADF;
1207 goto out;
1208 }
1209 sock = netlink_getsockbyfilp(f.file);
1210 fdput(f);
1211 if (IS_ERR(sock)) {
1212 ret = PTR_ERR(sock);
1213 sock = NULL;
1214 goto out;
1215 }
1216
1217 timeo = MAX_SCHEDULE_TIMEOUT;
1218 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1219 if (ret == 1) {
1220 sock = NULL;
1221 goto retry;
1222 }
1223 if (ret) {
1224 sock = NULL;
1225 nc = NULL;
1226 goto out;
1227 }
1228 }
1229 }
1230
1231 f = fdget(mqdes);
1232 if (!f.file) {
1233 ret = -EBADF;
1234 goto out;
1235 }
1236
1237 inode = file_inode(f.file);
1238 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1239 ret = -EBADF;
1240 goto out_fput;
1241 }
1242 info = MQUEUE_I(inode);
1243
1244 ret = 0;
1245 spin_lock(&info->lock);
1246 if (notification == NULL) {
1247 if (info->notify_owner == task_tgid(current)) {
1248 remove_notification(info);
1249 inode->i_atime = inode->i_ctime = current_time(inode);
1250 }
1251 } else if (info->notify_owner != NULL) {
1252 ret = -EBUSY;
1253 } else {
1254 switch (notification->sigev_notify) {
1255 case SIGEV_NONE:
1256 info->notify.sigev_notify = SIGEV_NONE;
1257 break;
1258 case SIGEV_THREAD:
1259 info->notify_sock = sock;
1260 info->notify_cookie = nc;
1261 sock = NULL;
1262 nc = NULL;
1263 info->notify.sigev_notify = SIGEV_THREAD;
1264 break;
1265 case SIGEV_SIGNAL:
1266 info->notify.sigev_signo = notification->sigev_signo;
1267 info->notify.sigev_value = notification->sigev_value;
1268 info->notify.sigev_notify = SIGEV_SIGNAL;
1269 break;
1270 }
1271
1272 info->notify_owner = get_pid(task_tgid(current));
1273 info->notify_user_ns = get_user_ns(current_user_ns());
1274 inode->i_atime = inode->i_ctime = current_time(inode);
1275 }
1276 spin_unlock(&info->lock);
1277out_fput:
1278 fdput(f);
1279out:
1280 if (sock)
1281 netlink_detachskb(sock, nc);
1282 else if (nc)
1283 dev_kfree_skb(nc);
1284
1285 return ret;
1286}
1287
1288SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1289 const struct sigevent __user *, u_notification)
1290{
1291 struct sigevent n, *p = NULL;
1292 if (u_notification) {
1293 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1294 return -EFAULT;
1295 p = &n;
1296 }
1297 return do_mq_notify(mqdes, p);
1298}
1299
1300static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1301{
1302 struct fd f;
1303 struct inode *inode;
1304 struct mqueue_inode_info *info;
1305
1306 if (new && (new->mq_flags & (~O_NONBLOCK)))
1307 return -EINVAL;
1308
1309 f = fdget(mqdes);
1310 if (!f.file)
1311 return -EBADF;
1312
1313 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1314 fdput(f);
1315 return -EBADF;
1316 }
1317
1318 inode = file_inode(f.file);
1319 info = MQUEUE_I(inode);
1320
1321 spin_lock(&info->lock);
1322
1323 if (old) {
1324 *old = info->attr;
1325 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1326 }
1327 if (new) {
1328 audit_mq_getsetattr(mqdes, new);
1329 spin_lock(&f.file->f_lock);
1330 if (new->mq_flags & O_NONBLOCK)
1331 f.file->f_flags |= O_NONBLOCK;
1332 else
1333 f.file->f_flags &= ~O_NONBLOCK;
1334 spin_unlock(&f.file->f_lock);
1335
1336 inode->i_atime = inode->i_ctime = current_time(inode);
1337 }
1338
1339 spin_unlock(&info->lock);
1340 fdput(f);
1341 return 0;
1342}
1343
1344SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1345 const struct mq_attr __user *, u_mqstat,
1346 struct mq_attr __user *, u_omqstat)
1347{
1348 int ret;
1349 struct mq_attr mqstat, omqstat;
1350 struct mq_attr *new = NULL, *old = NULL;
1351
1352 if (u_mqstat) {
1353 new = &mqstat;
1354 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1355 return -EFAULT;
1356 }
1357 if (u_omqstat)
1358 old = &omqstat;
1359
1360 ret = do_mq_getsetattr(mqdes, new, old);
1361 if (ret || !old)
1362 return ret;
1363
1364 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1365 return -EFAULT;
1366 return 0;
1367}
1368
1369#ifdef CONFIG_COMPAT
1370
1371struct compat_mq_attr {
1372 compat_long_t mq_flags; /* message queue flags */
1373 compat_long_t mq_maxmsg; /* maximum number of messages */
1374 compat_long_t mq_msgsize; /* maximum message size */
1375 compat_long_t mq_curmsgs; /* number of messages currently queued */
1376 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1377};
1378
1379static inline int get_compat_mq_attr(struct mq_attr *attr,
1380 const struct compat_mq_attr __user *uattr)
1381{
1382 struct compat_mq_attr v;
1383
1384 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1385 return -EFAULT;
1386
1387 memset(attr, 0, sizeof(*attr));
1388 attr->mq_flags = v.mq_flags;
1389 attr->mq_maxmsg = v.mq_maxmsg;
1390 attr->mq_msgsize = v.mq_msgsize;
1391 attr->mq_curmsgs = v.mq_curmsgs;
1392 return 0;
1393}
1394
1395static inline int put_compat_mq_attr(const struct mq_attr *attr,
1396 struct compat_mq_attr __user *uattr)
1397{
1398 struct compat_mq_attr v;
1399
1400 memset(&v, 0, sizeof(v));
1401 v.mq_flags = attr->mq_flags;
1402 v.mq_maxmsg = attr->mq_maxmsg;
1403 v.mq_msgsize = attr->mq_msgsize;
1404 v.mq_curmsgs = attr->mq_curmsgs;
1405 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1406 return -EFAULT;
1407 return 0;
1408}
1409
1410COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1411 int, oflag, compat_mode_t, mode,
1412 struct compat_mq_attr __user *, u_attr)
1413{
1414 struct mq_attr attr, *p = NULL;
1415 if (u_attr && oflag & O_CREAT) {
1416 p = &attr;
1417 if (get_compat_mq_attr(&attr, u_attr))
1418 return -EFAULT;
1419 }
1420 return do_mq_open(u_name, oflag, mode, p);
1421}
1422
1423static int compat_prepare_timeout(const struct compat_timespec __user *p,
1424 struct timespec64 *ts)
1425{
1426 if (compat_get_timespec64(ts, p))
1427 return -EFAULT;
1428 if (!timespec64_valid(ts))
1429 return -EINVAL;
1430 return 0;
1431}
1432
1433COMPAT_SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes,
1434 const char __user *, u_msg_ptr,
1435 compat_size_t, msg_len, unsigned int, msg_prio,
1436 const struct compat_timespec __user *, u_abs_timeout)
1437{
1438 struct timespec64 ts, *p = NULL;
1439 if (u_abs_timeout) {
1440 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1441 if (res)
1442 return res;
1443 p = &ts;
1444 }
1445 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1446}
1447
1448COMPAT_SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes,
1449 char __user *, u_msg_ptr,
1450 compat_size_t, msg_len, unsigned int __user *, u_msg_prio,
1451 const struct compat_timespec __user *, u_abs_timeout)
1452{
1453 struct timespec64 ts, *p = NULL;
1454 if (u_abs_timeout) {
1455 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1456 if (res)
1457 return res;
1458 p = &ts;
1459 }
1460 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1461}
1462
1463COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1464 const struct compat_sigevent __user *, u_notification)
1465{
1466 struct sigevent n, *p = NULL;
1467 if (u_notification) {
1468 if (get_compat_sigevent(&n, u_notification))
1469 return -EFAULT;
1470 if (n.sigev_notify == SIGEV_THREAD)
1471 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1472 p = &n;
1473 }
1474 return do_mq_notify(mqdes, p);
1475}
1476
1477COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1478 const struct compat_mq_attr __user *, u_mqstat,
1479 struct compat_mq_attr __user *, u_omqstat)
1480{
1481 int ret;
1482 struct mq_attr mqstat, omqstat;
1483 struct mq_attr *new = NULL, *old = NULL;
1484
1485 if (u_mqstat) {
1486 new = &mqstat;
1487 if (get_compat_mq_attr(new, u_mqstat))
1488 return -EFAULT;
1489 }
1490 if (u_omqstat)
1491 old = &omqstat;
1492
1493 ret = do_mq_getsetattr(mqdes, new, old);
1494 if (ret || !old)
1495 return ret;
1496
1497 if (put_compat_mq_attr(old, u_omqstat))
1498 return -EFAULT;
1499 return 0;
1500}
1501#endif
1502
1503static const struct inode_operations mqueue_dir_inode_operations = {
1504 .lookup = simple_lookup,
1505 .create = mqueue_create,
1506 .unlink = mqueue_unlink,
1507};
1508
1509static const struct file_operations mqueue_file_operations = {
1510 .flush = mqueue_flush_file,
1511 .poll = mqueue_poll_file,
1512 .read = mqueue_read_file,
1513 .llseek = default_llseek,
1514};
1515
1516static const struct super_operations mqueue_super_ops = {
1517 .alloc_inode = mqueue_alloc_inode,
1518 .destroy_inode = mqueue_destroy_inode,
1519 .evict_inode = mqueue_evict_inode,
1520 .statfs = simple_statfs,
1521};
1522
1523static struct file_system_type mqueue_fs_type = {
1524 .name = "mqueue",
1525 .mount = mqueue_mount,
1526 .kill_sb = kill_litter_super,
1527 .fs_flags = FS_USERNS_MOUNT,
1528};
1529
1530int mq_init_ns(struct ipc_namespace *ns)
1531{
1532 ns->mq_queues_count = 0;
1533 ns->mq_queues_max = DFLT_QUEUESMAX;
1534 ns->mq_msg_max = DFLT_MSGMAX;
1535 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1536 ns->mq_msg_default = DFLT_MSG;
1537 ns->mq_msgsize_default = DFLT_MSGSIZE;
1538
1539 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1540 if (IS_ERR(ns->mq_mnt)) {
1541 int err = PTR_ERR(ns->mq_mnt);
1542 ns->mq_mnt = NULL;
1543 return err;
1544 }
1545 return 0;
1546}
1547
1548void mq_clear_sbinfo(struct ipc_namespace *ns)
1549{
1550 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1551}
1552
1553void mq_put_mnt(struct ipc_namespace *ns)
1554{
1555 kern_unmount(ns->mq_mnt);
1556}
1557
1558static int __init init_mqueue_fs(void)
1559{
1560 int error;
1561
1562 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1563 sizeof(struct mqueue_inode_info), 0,
1564 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1565 if (mqueue_inode_cachep == NULL)
1566 return -ENOMEM;
1567
1568 /* ignore failures - they are not fatal */
1569 mq_sysctl_table = mq_register_sysctl_table();
1570
1571 error = register_filesystem(&mqueue_fs_type);
1572 if (error)
1573 goto out_sysctl;
1574
1575 spin_lock_init(&mq_lock);
1576
1577 error = mq_init_ns(&init_ipc_ns);
1578 if (error)
1579 goto out_filesystem;
1580
1581 return 0;
1582
1583out_filesystem:
1584 unregister_filesystem(&mqueue_fs_type);
1585out_sysctl:
1586 if (mq_sysctl_table)
1587 unregister_sysctl_table(mq_sysctl_table);
1588 kmem_cache_destroy(mqueue_inode_cachep);
1589 return error;
1590}
1591
1592device_initcall(init_mqueue_fs);