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1/*
2 * POSIX message queues filesystem for Linux.
3 *
4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
5 * Michal Wronski (michal.wronski@gmail.com)
6 *
7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
8 * Lockless receive & send, fd based notify:
9 * Manfred Spraul (manfred@colorfullife.com)
10 *
11 * Audit: George Wilson (ltcgcw@us.ibm.com)
12 *
13 * This file is released under the GPL.
14 */
15
16#include <linux/capability.h>
17#include <linux/init.h>
18#include <linux/pagemap.h>
19#include <linux/file.h>
20#include <linux/mount.h>
21#include <linux/fs_context.h>
22#include <linux/namei.h>
23#include <linux/sysctl.h>
24#include <linux/poll.h>
25#include <linux/mqueue.h>
26#include <linux/msg.h>
27#include <linux/skbuff.h>
28#include <linux/vmalloc.h>
29#include <linux/netlink.h>
30#include <linux/syscalls.h>
31#include <linux/audit.h>
32#include <linux/signal.h>
33#include <linux/mutex.h>
34#include <linux/nsproxy.h>
35#include <linux/pid.h>
36#include <linux/ipc_namespace.h>
37#include <linux/user_namespace.h>
38#include <linux/slab.h>
39#include <linux/sched/wake_q.h>
40#include <linux/sched/signal.h>
41#include <linux/sched/user.h>
42
43#include <net/sock.h>
44#include "util.h"
45
46struct mqueue_fs_context {
47 struct ipc_namespace *ipc_ns;
48};
49
50#define MQUEUE_MAGIC 0x19800202
51#define DIRENT_SIZE 20
52#define FILENT_SIZE 80
53
54#define SEND 0
55#define RECV 1
56
57#define STATE_NONE 0
58#define STATE_READY 1
59
60struct posix_msg_tree_node {
61 struct rb_node rb_node;
62 struct list_head msg_list;
63 int priority;
64};
65
66/*
67 * Locking:
68 *
69 * Accesses to a message queue are synchronized by acquiring info->lock.
70 *
71 * There are two notable exceptions:
72 * - The actual wakeup of a sleeping task is performed using the wake_q
73 * framework. info->lock is already released when wake_up_q is called.
74 * - The exit codepaths after sleeping check ext_wait_queue->state without
75 * any locks. If it is STATE_READY, then the syscall is completed without
76 * acquiring info->lock.
77 *
78 * MQ_BARRIER:
79 * To achieve proper release/acquire memory barrier pairing, the state is set to
80 * STATE_READY with smp_store_release(), and it is read with READ_ONCE followed
81 * by smp_acquire__after_ctrl_dep(). In addition, wake_q_add_safe() is used.
82 *
83 * This prevents the following races:
84 *
85 * 1) With the simple wake_q_add(), the task could be gone already before
86 * the increase of the reference happens
87 * Thread A
88 * Thread B
89 * WRITE_ONCE(wait.state, STATE_NONE);
90 * schedule_hrtimeout()
91 * wake_q_add(A)
92 * if (cmpxchg()) // success
93 * ->state = STATE_READY (reordered)
94 * <timeout returns>
95 * if (wait.state == STATE_READY) return;
96 * sysret to user space
97 * sys_exit()
98 * get_task_struct() // UaF
99 *
100 * Solution: Use wake_q_add_safe() and perform the get_task_struct() before
101 * the smp_store_release() that does ->state = STATE_READY.
102 *
103 * 2) Without proper _release/_acquire barriers, the woken up task
104 * could read stale data
105 *
106 * Thread A
107 * Thread B
108 * do_mq_timedreceive
109 * WRITE_ONCE(wait.state, STATE_NONE);
110 * schedule_hrtimeout()
111 * state = STATE_READY;
112 * <timeout returns>
113 * if (wait.state == STATE_READY) return;
114 * msg_ptr = wait.msg; // Access to stale data!
115 * receiver->msg = message; (reordered)
116 *
117 * Solution: use _release and _acquire barriers.
118 *
119 * 3) There is intentionally no barrier when setting current->state
120 * to TASK_INTERRUPTIBLE: spin_unlock(&info->lock) provides the
121 * release memory barrier, and the wakeup is triggered when holding
122 * info->lock, i.e. spin_lock(&info->lock) provided a pairing
123 * acquire memory barrier.
124 */
125
126struct ext_wait_queue { /* queue of sleeping tasks */
127 struct task_struct *task;
128 struct list_head list;
129 struct msg_msg *msg; /* ptr of loaded message */
130 int state; /* one of STATE_* values */
131};
132
133struct mqueue_inode_info {
134 spinlock_t lock;
135 struct inode vfs_inode;
136 wait_queue_head_t wait_q;
137
138 struct rb_root msg_tree;
139 struct rb_node *msg_tree_rightmost;
140 struct posix_msg_tree_node *node_cache;
141 struct mq_attr attr;
142
143 struct sigevent notify;
144 struct pid *notify_owner;
145 u32 notify_self_exec_id;
146 struct user_namespace *notify_user_ns;
147 struct ucounts *ucounts; /* user who created, for accounting */
148 struct sock *notify_sock;
149 struct sk_buff *notify_cookie;
150
151 /* for tasks waiting for free space and messages, respectively */
152 struct ext_wait_queue e_wait_q[2];
153
154 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
155};
156
157static struct file_system_type mqueue_fs_type;
158static const struct inode_operations mqueue_dir_inode_operations;
159static const struct file_operations mqueue_file_operations;
160static const struct super_operations mqueue_super_ops;
161static const struct fs_context_operations mqueue_fs_context_ops;
162static void remove_notification(struct mqueue_inode_info *info);
163
164static struct kmem_cache *mqueue_inode_cachep;
165
166static struct ctl_table_header *mq_sysctl_table;
167
168static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
169{
170 return container_of(inode, struct mqueue_inode_info, vfs_inode);
171}
172
173/*
174 * This routine should be called with the mq_lock held.
175 */
176static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
177{
178 return get_ipc_ns(inode->i_sb->s_fs_info);
179}
180
181static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
182{
183 struct ipc_namespace *ns;
184
185 spin_lock(&mq_lock);
186 ns = __get_ns_from_inode(inode);
187 spin_unlock(&mq_lock);
188 return ns;
189}
190
191/* Auxiliary functions to manipulate messages' list */
192static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
193{
194 struct rb_node **p, *parent = NULL;
195 struct posix_msg_tree_node *leaf;
196 bool rightmost = true;
197
198 p = &info->msg_tree.rb_node;
199 while (*p) {
200 parent = *p;
201 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
202
203 if (likely(leaf->priority == msg->m_type))
204 goto insert_msg;
205 else if (msg->m_type < leaf->priority) {
206 p = &(*p)->rb_left;
207 rightmost = false;
208 } else
209 p = &(*p)->rb_right;
210 }
211 if (info->node_cache) {
212 leaf = info->node_cache;
213 info->node_cache = NULL;
214 } else {
215 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
216 if (!leaf)
217 return -ENOMEM;
218 INIT_LIST_HEAD(&leaf->msg_list);
219 }
220 leaf->priority = msg->m_type;
221
222 if (rightmost)
223 info->msg_tree_rightmost = &leaf->rb_node;
224
225 rb_link_node(&leaf->rb_node, parent, p);
226 rb_insert_color(&leaf->rb_node, &info->msg_tree);
227insert_msg:
228 info->attr.mq_curmsgs++;
229 info->qsize += msg->m_ts;
230 list_add_tail(&msg->m_list, &leaf->msg_list);
231 return 0;
232}
233
234static inline void msg_tree_erase(struct posix_msg_tree_node *leaf,
235 struct mqueue_inode_info *info)
236{
237 struct rb_node *node = &leaf->rb_node;
238
239 if (info->msg_tree_rightmost == node)
240 info->msg_tree_rightmost = rb_prev(node);
241
242 rb_erase(node, &info->msg_tree);
243 if (info->node_cache)
244 kfree(leaf);
245 else
246 info->node_cache = leaf;
247}
248
249static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
250{
251 struct rb_node *parent = NULL;
252 struct posix_msg_tree_node *leaf;
253 struct msg_msg *msg;
254
255try_again:
256 /*
257 * During insert, low priorities go to the left and high to the
258 * right. On receive, we want the highest priorities first, so
259 * walk all the way to the right.
260 */
261 parent = info->msg_tree_rightmost;
262 if (!parent) {
263 if (info->attr.mq_curmsgs) {
264 pr_warn_once("Inconsistency in POSIX message queue, "
265 "no tree element, but supposedly messages "
266 "should exist!\n");
267 info->attr.mq_curmsgs = 0;
268 }
269 return NULL;
270 }
271 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
272 if (unlikely(list_empty(&leaf->msg_list))) {
273 pr_warn_once("Inconsistency in POSIX message queue, "
274 "empty leaf node but we haven't implemented "
275 "lazy leaf delete!\n");
276 msg_tree_erase(leaf, info);
277 goto try_again;
278 } else {
279 msg = list_first_entry(&leaf->msg_list,
280 struct msg_msg, m_list);
281 list_del(&msg->m_list);
282 if (list_empty(&leaf->msg_list)) {
283 msg_tree_erase(leaf, info);
284 }
285 }
286 info->attr.mq_curmsgs--;
287 info->qsize -= msg->m_ts;
288 return msg;
289}
290
291static struct inode *mqueue_get_inode(struct super_block *sb,
292 struct ipc_namespace *ipc_ns, umode_t mode,
293 struct mq_attr *attr)
294{
295 struct inode *inode;
296 int ret = -ENOMEM;
297
298 inode = new_inode(sb);
299 if (!inode)
300 goto err;
301
302 inode->i_ino = get_next_ino();
303 inode->i_mode = mode;
304 inode->i_uid = current_fsuid();
305 inode->i_gid = current_fsgid();
306 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
307
308 if (S_ISREG(mode)) {
309 struct mqueue_inode_info *info;
310 unsigned long mq_bytes, mq_treesize;
311
312 inode->i_fop = &mqueue_file_operations;
313 inode->i_size = FILENT_SIZE;
314 /* mqueue specific info */
315 info = MQUEUE_I(inode);
316 spin_lock_init(&info->lock);
317 init_waitqueue_head(&info->wait_q);
318 INIT_LIST_HEAD(&info->e_wait_q[0].list);
319 INIT_LIST_HEAD(&info->e_wait_q[1].list);
320 info->notify_owner = NULL;
321 info->notify_user_ns = NULL;
322 info->qsize = 0;
323 info->ucounts = NULL; /* set when all is ok */
324 info->msg_tree = RB_ROOT;
325 info->msg_tree_rightmost = NULL;
326 info->node_cache = NULL;
327 memset(&info->attr, 0, sizeof(info->attr));
328 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
329 ipc_ns->mq_msg_default);
330 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
331 ipc_ns->mq_msgsize_default);
332 if (attr) {
333 info->attr.mq_maxmsg = attr->mq_maxmsg;
334 info->attr.mq_msgsize = attr->mq_msgsize;
335 }
336 /*
337 * We used to allocate a static array of pointers and account
338 * the size of that array as well as one msg_msg struct per
339 * possible message into the queue size. That's no longer
340 * accurate as the queue is now an rbtree and will grow and
341 * shrink depending on usage patterns. We can, however, still
342 * account one msg_msg struct per message, but the nodes are
343 * allocated depending on priority usage, and most programs
344 * only use one, or a handful, of priorities. However, since
345 * this is pinned memory, we need to assume worst case, so
346 * that means the min(mq_maxmsg, max_priorities) * struct
347 * posix_msg_tree_node.
348 */
349
350 ret = -EINVAL;
351 if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
352 goto out_inode;
353 if (capable(CAP_SYS_RESOURCE)) {
354 if (info->attr.mq_maxmsg > HARD_MSGMAX ||
355 info->attr.mq_msgsize > HARD_MSGSIZEMAX)
356 goto out_inode;
357 } else {
358 if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
359 info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
360 goto out_inode;
361 }
362 ret = -EOVERFLOW;
363 /* check for overflow */
364 if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
365 goto out_inode;
366 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
367 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
368 sizeof(struct posix_msg_tree_node);
369 mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
370 if (mq_bytes + mq_treesize < mq_bytes)
371 goto out_inode;
372 mq_bytes += mq_treesize;
373 info->ucounts = get_ucounts(current_ucounts());
374 if (info->ucounts) {
375 long msgqueue;
376
377 spin_lock(&mq_lock);
378 msgqueue = inc_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
379 if (msgqueue == LONG_MAX || msgqueue > rlimit(RLIMIT_MSGQUEUE)) {
380 dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
381 spin_unlock(&mq_lock);
382 put_ucounts(info->ucounts);
383 info->ucounts = NULL;
384 /* mqueue_evict_inode() releases info->messages */
385 ret = -EMFILE;
386 goto out_inode;
387 }
388 spin_unlock(&mq_lock);
389 }
390 } else if (S_ISDIR(mode)) {
391 inc_nlink(inode);
392 /* Some things misbehave if size == 0 on a directory */
393 inode->i_size = 2 * DIRENT_SIZE;
394 inode->i_op = &mqueue_dir_inode_operations;
395 inode->i_fop = &simple_dir_operations;
396 }
397
398 return inode;
399out_inode:
400 iput(inode);
401err:
402 return ERR_PTR(ret);
403}
404
405static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc)
406{
407 struct inode *inode;
408 struct ipc_namespace *ns = sb->s_fs_info;
409
410 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
411 sb->s_blocksize = PAGE_SIZE;
412 sb->s_blocksize_bits = PAGE_SHIFT;
413 sb->s_magic = MQUEUE_MAGIC;
414 sb->s_op = &mqueue_super_ops;
415
416 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
417 if (IS_ERR(inode))
418 return PTR_ERR(inode);
419
420 sb->s_root = d_make_root(inode);
421 if (!sb->s_root)
422 return -ENOMEM;
423 return 0;
424}
425
426static int mqueue_get_tree(struct fs_context *fc)
427{
428 struct mqueue_fs_context *ctx = fc->fs_private;
429
430 return get_tree_keyed(fc, mqueue_fill_super, ctx->ipc_ns);
431}
432
433static void mqueue_fs_context_free(struct fs_context *fc)
434{
435 struct mqueue_fs_context *ctx = fc->fs_private;
436
437 put_ipc_ns(ctx->ipc_ns);
438 kfree(ctx);
439}
440
441static int mqueue_init_fs_context(struct fs_context *fc)
442{
443 struct mqueue_fs_context *ctx;
444
445 ctx = kzalloc(sizeof(struct mqueue_fs_context), GFP_KERNEL);
446 if (!ctx)
447 return -ENOMEM;
448
449 ctx->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
450 put_user_ns(fc->user_ns);
451 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
452 fc->fs_private = ctx;
453 fc->ops = &mqueue_fs_context_ops;
454 return 0;
455}
456
457static struct vfsmount *mq_create_mount(struct ipc_namespace *ns)
458{
459 struct mqueue_fs_context *ctx;
460 struct fs_context *fc;
461 struct vfsmount *mnt;
462
463 fc = fs_context_for_mount(&mqueue_fs_type, SB_KERNMOUNT);
464 if (IS_ERR(fc))
465 return ERR_CAST(fc);
466
467 ctx = fc->fs_private;
468 put_ipc_ns(ctx->ipc_ns);
469 ctx->ipc_ns = get_ipc_ns(ns);
470 put_user_ns(fc->user_ns);
471 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
472
473 mnt = fc_mount(fc);
474 put_fs_context(fc);
475 return mnt;
476}
477
478static void init_once(void *foo)
479{
480 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
481
482 inode_init_once(&p->vfs_inode);
483}
484
485static struct inode *mqueue_alloc_inode(struct super_block *sb)
486{
487 struct mqueue_inode_info *ei;
488
489 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
490 if (!ei)
491 return NULL;
492 return &ei->vfs_inode;
493}
494
495static void mqueue_free_inode(struct inode *inode)
496{
497 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
498}
499
500static void mqueue_evict_inode(struct inode *inode)
501{
502 struct mqueue_inode_info *info;
503 struct ipc_namespace *ipc_ns;
504 struct msg_msg *msg, *nmsg;
505 LIST_HEAD(tmp_msg);
506
507 clear_inode(inode);
508
509 if (S_ISDIR(inode->i_mode))
510 return;
511
512 ipc_ns = get_ns_from_inode(inode);
513 info = MQUEUE_I(inode);
514 spin_lock(&info->lock);
515 while ((msg = msg_get(info)) != NULL)
516 list_add_tail(&msg->m_list, &tmp_msg);
517 kfree(info->node_cache);
518 spin_unlock(&info->lock);
519
520 list_for_each_entry_safe(msg, nmsg, &tmp_msg, m_list) {
521 list_del(&msg->m_list);
522 free_msg(msg);
523 }
524
525 if (info->ucounts) {
526 unsigned long mq_bytes, mq_treesize;
527
528 /* Total amount of bytes accounted for the mqueue */
529 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
530 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
531 sizeof(struct posix_msg_tree_node);
532
533 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
534 info->attr.mq_msgsize);
535
536 spin_lock(&mq_lock);
537 dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
538 /*
539 * get_ns_from_inode() ensures that the
540 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
541 * to which we now hold a reference, or it is NULL.
542 * We can't put it here under mq_lock, though.
543 */
544 if (ipc_ns)
545 ipc_ns->mq_queues_count--;
546 spin_unlock(&mq_lock);
547 put_ucounts(info->ucounts);
548 info->ucounts = NULL;
549 }
550 if (ipc_ns)
551 put_ipc_ns(ipc_ns);
552}
553
554static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
555{
556 struct inode *dir = dentry->d_parent->d_inode;
557 struct inode *inode;
558 struct mq_attr *attr = arg;
559 int error;
560 struct ipc_namespace *ipc_ns;
561
562 spin_lock(&mq_lock);
563 ipc_ns = __get_ns_from_inode(dir);
564 if (!ipc_ns) {
565 error = -EACCES;
566 goto out_unlock;
567 }
568
569 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
570 !capable(CAP_SYS_RESOURCE)) {
571 error = -ENOSPC;
572 goto out_unlock;
573 }
574 ipc_ns->mq_queues_count++;
575 spin_unlock(&mq_lock);
576
577 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
578 if (IS_ERR(inode)) {
579 error = PTR_ERR(inode);
580 spin_lock(&mq_lock);
581 ipc_ns->mq_queues_count--;
582 goto out_unlock;
583 }
584
585 put_ipc_ns(ipc_ns);
586 dir->i_size += DIRENT_SIZE;
587 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
588
589 d_instantiate(dentry, inode);
590 dget(dentry);
591 return 0;
592out_unlock:
593 spin_unlock(&mq_lock);
594 if (ipc_ns)
595 put_ipc_ns(ipc_ns);
596 return error;
597}
598
599static int mqueue_create(struct user_namespace *mnt_userns, struct inode *dir,
600 struct dentry *dentry, umode_t mode, bool excl)
601{
602 return mqueue_create_attr(dentry, mode, NULL);
603}
604
605static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
606{
607 struct inode *inode = d_inode(dentry);
608
609 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
610 dir->i_size -= DIRENT_SIZE;
611 drop_nlink(inode);
612 dput(dentry);
613 return 0;
614}
615
616/*
617* This is routine for system read from queue file.
618* To avoid mess with doing here some sort of mq_receive we allow
619* to read only queue size & notification info (the only values
620* that are interesting from user point of view and aren't accessible
621* through std routines)
622*/
623static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
624 size_t count, loff_t *off)
625{
626 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
627 char buffer[FILENT_SIZE];
628 ssize_t ret;
629
630 spin_lock(&info->lock);
631 snprintf(buffer, sizeof(buffer),
632 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
633 info->qsize,
634 info->notify_owner ? info->notify.sigev_notify : 0,
635 (info->notify_owner &&
636 info->notify.sigev_notify == SIGEV_SIGNAL) ?
637 info->notify.sigev_signo : 0,
638 pid_vnr(info->notify_owner));
639 spin_unlock(&info->lock);
640 buffer[sizeof(buffer)-1] = '\0';
641
642 ret = simple_read_from_buffer(u_data, count, off, buffer,
643 strlen(buffer));
644 if (ret <= 0)
645 return ret;
646
647 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
648 return ret;
649}
650
651static int mqueue_flush_file(struct file *filp, fl_owner_t id)
652{
653 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
654
655 spin_lock(&info->lock);
656 if (task_tgid(current) == info->notify_owner)
657 remove_notification(info);
658
659 spin_unlock(&info->lock);
660 return 0;
661}
662
663static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
664{
665 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
666 __poll_t retval = 0;
667
668 poll_wait(filp, &info->wait_q, poll_tab);
669
670 spin_lock(&info->lock);
671 if (info->attr.mq_curmsgs)
672 retval = EPOLLIN | EPOLLRDNORM;
673
674 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
675 retval |= EPOLLOUT | EPOLLWRNORM;
676 spin_unlock(&info->lock);
677
678 return retval;
679}
680
681/* Adds current to info->e_wait_q[sr] before element with smaller prio */
682static void wq_add(struct mqueue_inode_info *info, int sr,
683 struct ext_wait_queue *ewp)
684{
685 struct ext_wait_queue *walk;
686
687 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
688 if (walk->task->prio <= current->prio) {
689 list_add_tail(&ewp->list, &walk->list);
690 return;
691 }
692 }
693 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
694}
695
696/*
697 * Puts current task to sleep. Caller must hold queue lock. After return
698 * lock isn't held.
699 * sr: SEND or RECV
700 */
701static int wq_sleep(struct mqueue_inode_info *info, int sr,
702 ktime_t *timeout, struct ext_wait_queue *ewp)
703 __releases(&info->lock)
704{
705 int retval;
706 signed long time;
707
708 wq_add(info, sr, ewp);
709
710 for (;;) {
711 /* memory barrier not required, we hold info->lock */
712 __set_current_state(TASK_INTERRUPTIBLE);
713
714 spin_unlock(&info->lock);
715 time = schedule_hrtimeout_range_clock(timeout, 0,
716 HRTIMER_MODE_ABS, CLOCK_REALTIME);
717
718 if (READ_ONCE(ewp->state) == STATE_READY) {
719 /* see MQ_BARRIER for purpose/pairing */
720 smp_acquire__after_ctrl_dep();
721 retval = 0;
722 goto out;
723 }
724 spin_lock(&info->lock);
725
726 /* we hold info->lock, so no memory barrier required */
727 if (READ_ONCE(ewp->state) == STATE_READY) {
728 retval = 0;
729 goto out_unlock;
730 }
731 if (signal_pending(current)) {
732 retval = -ERESTARTSYS;
733 break;
734 }
735 if (time == 0) {
736 retval = -ETIMEDOUT;
737 break;
738 }
739 }
740 list_del(&ewp->list);
741out_unlock:
742 spin_unlock(&info->lock);
743out:
744 return retval;
745}
746
747/*
748 * Returns waiting task that should be serviced first or NULL if none exists
749 */
750static struct ext_wait_queue *wq_get_first_waiter(
751 struct mqueue_inode_info *info, int sr)
752{
753 struct list_head *ptr;
754
755 ptr = info->e_wait_q[sr].list.prev;
756 if (ptr == &info->e_wait_q[sr].list)
757 return NULL;
758 return list_entry(ptr, struct ext_wait_queue, list);
759}
760
761
762static inline void set_cookie(struct sk_buff *skb, char code)
763{
764 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
765}
766
767/*
768 * The next function is only to split too long sys_mq_timedsend
769 */
770static void __do_notify(struct mqueue_inode_info *info)
771{
772 /* notification
773 * invoked when there is registered process and there isn't process
774 * waiting synchronously for message AND state of queue changed from
775 * empty to not empty. Here we are sure that no one is waiting
776 * synchronously. */
777 if (info->notify_owner &&
778 info->attr.mq_curmsgs == 1) {
779 switch (info->notify.sigev_notify) {
780 case SIGEV_NONE:
781 break;
782 case SIGEV_SIGNAL: {
783 struct kernel_siginfo sig_i;
784 struct task_struct *task;
785
786 /* do_mq_notify() accepts sigev_signo == 0, why?? */
787 if (!info->notify.sigev_signo)
788 break;
789
790 clear_siginfo(&sig_i);
791 sig_i.si_signo = info->notify.sigev_signo;
792 sig_i.si_errno = 0;
793 sig_i.si_code = SI_MESGQ;
794 sig_i.si_value = info->notify.sigev_value;
795 rcu_read_lock();
796 /* map current pid/uid into info->owner's namespaces */
797 sig_i.si_pid = task_tgid_nr_ns(current,
798 ns_of_pid(info->notify_owner));
799 sig_i.si_uid = from_kuid_munged(info->notify_user_ns,
800 current_uid());
801 /*
802 * We can't use kill_pid_info(), this signal should
803 * bypass check_kill_permission(). It is from kernel
804 * but si_fromuser() can't know this.
805 * We do check the self_exec_id, to avoid sending
806 * signals to programs that don't expect them.
807 */
808 task = pid_task(info->notify_owner, PIDTYPE_TGID);
809 if (task && task->self_exec_id ==
810 info->notify_self_exec_id) {
811 do_send_sig_info(info->notify.sigev_signo,
812 &sig_i, task, PIDTYPE_TGID);
813 }
814 rcu_read_unlock();
815 break;
816 }
817 case SIGEV_THREAD:
818 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
819 netlink_sendskb(info->notify_sock, info->notify_cookie);
820 break;
821 }
822 /* after notification unregisters process */
823 put_pid(info->notify_owner);
824 put_user_ns(info->notify_user_ns);
825 info->notify_owner = NULL;
826 info->notify_user_ns = NULL;
827 }
828 wake_up(&info->wait_q);
829}
830
831static int prepare_timeout(const struct __kernel_timespec __user *u_abs_timeout,
832 struct timespec64 *ts)
833{
834 if (get_timespec64(ts, u_abs_timeout))
835 return -EFAULT;
836 if (!timespec64_valid(ts))
837 return -EINVAL;
838 return 0;
839}
840
841static void remove_notification(struct mqueue_inode_info *info)
842{
843 if (info->notify_owner != NULL &&
844 info->notify.sigev_notify == SIGEV_THREAD) {
845 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
846 netlink_sendskb(info->notify_sock, info->notify_cookie);
847 }
848 put_pid(info->notify_owner);
849 put_user_ns(info->notify_user_ns);
850 info->notify_owner = NULL;
851 info->notify_user_ns = NULL;
852}
853
854static int prepare_open(struct dentry *dentry, int oflag, int ro,
855 umode_t mode, struct filename *name,
856 struct mq_attr *attr)
857{
858 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
859 MAY_READ | MAY_WRITE };
860 int acc;
861
862 if (d_really_is_negative(dentry)) {
863 if (!(oflag & O_CREAT))
864 return -ENOENT;
865 if (ro)
866 return ro;
867 audit_inode_parent_hidden(name, dentry->d_parent);
868 return vfs_mkobj(dentry, mode & ~current_umask(),
869 mqueue_create_attr, attr);
870 }
871 /* it already existed */
872 audit_inode(name, dentry, 0);
873 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
874 return -EEXIST;
875 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
876 return -EINVAL;
877 acc = oflag2acc[oflag & O_ACCMODE];
878 return inode_permission(&init_user_ns, d_inode(dentry), acc);
879}
880
881static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
882 struct mq_attr *attr)
883{
884 struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
885 struct dentry *root = mnt->mnt_root;
886 struct filename *name;
887 struct path path;
888 int fd, error;
889 int ro;
890
891 audit_mq_open(oflag, mode, attr);
892
893 if (IS_ERR(name = getname(u_name)))
894 return PTR_ERR(name);
895
896 fd = get_unused_fd_flags(O_CLOEXEC);
897 if (fd < 0)
898 goto out_putname;
899
900 ro = mnt_want_write(mnt); /* we'll drop it in any case */
901 inode_lock(d_inode(root));
902 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
903 if (IS_ERR(path.dentry)) {
904 error = PTR_ERR(path.dentry);
905 goto out_putfd;
906 }
907 path.mnt = mntget(mnt);
908 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
909 if (!error) {
910 struct file *file = dentry_open(&path, oflag, current_cred());
911 if (!IS_ERR(file))
912 fd_install(fd, file);
913 else
914 error = PTR_ERR(file);
915 }
916 path_put(&path);
917out_putfd:
918 if (error) {
919 put_unused_fd(fd);
920 fd = error;
921 }
922 inode_unlock(d_inode(root));
923 if (!ro)
924 mnt_drop_write(mnt);
925out_putname:
926 putname(name);
927 return fd;
928}
929
930SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
931 struct mq_attr __user *, u_attr)
932{
933 struct mq_attr attr;
934 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
935 return -EFAULT;
936
937 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
938}
939
940SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
941{
942 int err;
943 struct filename *name;
944 struct dentry *dentry;
945 struct inode *inode = NULL;
946 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
947 struct vfsmount *mnt = ipc_ns->mq_mnt;
948
949 name = getname(u_name);
950 if (IS_ERR(name))
951 return PTR_ERR(name);
952
953 audit_inode_parent_hidden(name, mnt->mnt_root);
954 err = mnt_want_write(mnt);
955 if (err)
956 goto out_name;
957 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
958 dentry = lookup_one_len(name->name, mnt->mnt_root,
959 strlen(name->name));
960 if (IS_ERR(dentry)) {
961 err = PTR_ERR(dentry);
962 goto out_unlock;
963 }
964
965 inode = d_inode(dentry);
966 if (!inode) {
967 err = -ENOENT;
968 } else {
969 ihold(inode);
970 err = vfs_unlink(&init_user_ns, d_inode(dentry->d_parent),
971 dentry, NULL);
972 }
973 dput(dentry);
974
975out_unlock:
976 inode_unlock(d_inode(mnt->mnt_root));
977 if (inode)
978 iput(inode);
979 mnt_drop_write(mnt);
980out_name:
981 putname(name);
982
983 return err;
984}
985
986/* Pipelined send and receive functions.
987 *
988 * If a receiver finds no waiting message, then it registers itself in the
989 * list of waiting receivers. A sender checks that list before adding the new
990 * message into the message array. If there is a waiting receiver, then it
991 * bypasses the message array and directly hands the message over to the
992 * receiver. The receiver accepts the message and returns without grabbing the
993 * queue spinlock:
994 *
995 * - Set pointer to message.
996 * - Queue the receiver task for later wakeup (without the info->lock).
997 * - Update its state to STATE_READY. Now the receiver can continue.
998 * - Wake up the process after the lock is dropped. Should the process wake up
999 * before this wakeup (due to a timeout or a signal) it will either see
1000 * STATE_READY and continue or acquire the lock to check the state again.
1001 *
1002 * The same algorithm is used for senders.
1003 */
1004
1005static inline void __pipelined_op(struct wake_q_head *wake_q,
1006 struct mqueue_inode_info *info,
1007 struct ext_wait_queue *this)
1008{
1009 struct task_struct *task;
1010
1011 list_del(&this->list);
1012 task = get_task_struct(this->task);
1013
1014 /* see MQ_BARRIER for purpose/pairing */
1015 smp_store_release(&this->state, STATE_READY);
1016 wake_q_add_safe(wake_q, task);
1017}
1018
1019/* pipelined_send() - send a message directly to the task waiting in
1020 * sys_mq_timedreceive() (without inserting message into a queue).
1021 */
1022static inline void pipelined_send(struct wake_q_head *wake_q,
1023 struct mqueue_inode_info *info,
1024 struct msg_msg *message,
1025 struct ext_wait_queue *receiver)
1026{
1027 receiver->msg = message;
1028 __pipelined_op(wake_q, info, receiver);
1029}
1030
1031/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
1032 * gets its message and put to the queue (we have one free place for sure). */
1033static inline void pipelined_receive(struct wake_q_head *wake_q,
1034 struct mqueue_inode_info *info)
1035{
1036 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
1037
1038 if (!sender) {
1039 /* for poll */
1040 wake_up_interruptible(&info->wait_q);
1041 return;
1042 }
1043 if (msg_insert(sender->msg, info))
1044 return;
1045
1046 __pipelined_op(wake_q, info, sender);
1047}
1048
1049static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
1050 size_t msg_len, unsigned int msg_prio,
1051 struct timespec64 *ts)
1052{
1053 struct fd f;
1054 struct inode *inode;
1055 struct ext_wait_queue wait;
1056 struct ext_wait_queue *receiver;
1057 struct msg_msg *msg_ptr;
1058 struct mqueue_inode_info *info;
1059 ktime_t expires, *timeout = NULL;
1060 struct posix_msg_tree_node *new_leaf = NULL;
1061 int ret = 0;
1062 DEFINE_WAKE_Q(wake_q);
1063
1064 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
1065 return -EINVAL;
1066
1067 if (ts) {
1068 expires = timespec64_to_ktime(*ts);
1069 timeout = &expires;
1070 }
1071
1072 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
1073
1074 f = fdget(mqdes);
1075 if (unlikely(!f.file)) {
1076 ret = -EBADF;
1077 goto out;
1078 }
1079
1080 inode = file_inode(f.file);
1081 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1082 ret = -EBADF;
1083 goto out_fput;
1084 }
1085 info = MQUEUE_I(inode);
1086 audit_file(f.file);
1087
1088 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
1089 ret = -EBADF;
1090 goto out_fput;
1091 }
1092
1093 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1094 ret = -EMSGSIZE;
1095 goto out_fput;
1096 }
1097
1098 /* First try to allocate memory, before doing anything with
1099 * existing queues. */
1100 msg_ptr = load_msg(u_msg_ptr, msg_len);
1101 if (IS_ERR(msg_ptr)) {
1102 ret = PTR_ERR(msg_ptr);
1103 goto out_fput;
1104 }
1105 msg_ptr->m_ts = msg_len;
1106 msg_ptr->m_type = msg_prio;
1107
1108 /*
1109 * msg_insert really wants us to have a valid, spare node struct so
1110 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1111 * fall back to that if necessary.
1112 */
1113 if (!info->node_cache)
1114 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1115
1116 spin_lock(&info->lock);
1117
1118 if (!info->node_cache && new_leaf) {
1119 /* Save our speculative allocation into the cache */
1120 INIT_LIST_HEAD(&new_leaf->msg_list);
1121 info->node_cache = new_leaf;
1122 new_leaf = NULL;
1123 } else {
1124 kfree(new_leaf);
1125 }
1126
1127 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1128 if (f.file->f_flags & O_NONBLOCK) {
1129 ret = -EAGAIN;
1130 } else {
1131 wait.task = current;
1132 wait.msg = (void *) msg_ptr;
1133
1134 /* memory barrier not required, we hold info->lock */
1135 WRITE_ONCE(wait.state, STATE_NONE);
1136 ret = wq_sleep(info, SEND, timeout, &wait);
1137 /*
1138 * wq_sleep must be called with info->lock held, and
1139 * returns with the lock released
1140 */
1141 goto out_free;
1142 }
1143 } else {
1144 receiver = wq_get_first_waiter(info, RECV);
1145 if (receiver) {
1146 pipelined_send(&wake_q, info, msg_ptr, receiver);
1147 } else {
1148 /* adds message to the queue */
1149 ret = msg_insert(msg_ptr, info);
1150 if (ret)
1151 goto out_unlock;
1152 __do_notify(info);
1153 }
1154 inode->i_atime = inode->i_mtime = inode->i_ctime =
1155 current_time(inode);
1156 }
1157out_unlock:
1158 spin_unlock(&info->lock);
1159 wake_up_q(&wake_q);
1160out_free:
1161 if (ret)
1162 free_msg(msg_ptr);
1163out_fput:
1164 fdput(f);
1165out:
1166 return ret;
1167}
1168
1169static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1170 size_t msg_len, unsigned int __user *u_msg_prio,
1171 struct timespec64 *ts)
1172{
1173 ssize_t ret;
1174 struct msg_msg *msg_ptr;
1175 struct fd f;
1176 struct inode *inode;
1177 struct mqueue_inode_info *info;
1178 struct ext_wait_queue wait;
1179 ktime_t expires, *timeout = NULL;
1180 struct posix_msg_tree_node *new_leaf = NULL;
1181
1182 if (ts) {
1183 expires = timespec64_to_ktime(*ts);
1184 timeout = &expires;
1185 }
1186
1187 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1188
1189 f = fdget(mqdes);
1190 if (unlikely(!f.file)) {
1191 ret = -EBADF;
1192 goto out;
1193 }
1194
1195 inode = file_inode(f.file);
1196 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1197 ret = -EBADF;
1198 goto out_fput;
1199 }
1200 info = MQUEUE_I(inode);
1201 audit_file(f.file);
1202
1203 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1204 ret = -EBADF;
1205 goto out_fput;
1206 }
1207
1208 /* checks if buffer is big enough */
1209 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1210 ret = -EMSGSIZE;
1211 goto out_fput;
1212 }
1213
1214 /*
1215 * msg_insert really wants us to have a valid, spare node struct so
1216 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1217 * fall back to that if necessary.
1218 */
1219 if (!info->node_cache)
1220 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1221
1222 spin_lock(&info->lock);
1223
1224 if (!info->node_cache && new_leaf) {
1225 /* Save our speculative allocation into the cache */
1226 INIT_LIST_HEAD(&new_leaf->msg_list);
1227 info->node_cache = new_leaf;
1228 } else {
1229 kfree(new_leaf);
1230 }
1231
1232 if (info->attr.mq_curmsgs == 0) {
1233 if (f.file->f_flags & O_NONBLOCK) {
1234 spin_unlock(&info->lock);
1235 ret = -EAGAIN;
1236 } else {
1237 wait.task = current;
1238
1239 /* memory barrier not required, we hold info->lock */
1240 WRITE_ONCE(wait.state, STATE_NONE);
1241 ret = wq_sleep(info, RECV, timeout, &wait);
1242 msg_ptr = wait.msg;
1243 }
1244 } else {
1245 DEFINE_WAKE_Q(wake_q);
1246
1247 msg_ptr = msg_get(info);
1248
1249 inode->i_atime = inode->i_mtime = inode->i_ctime =
1250 current_time(inode);
1251
1252 /* There is now free space in queue. */
1253 pipelined_receive(&wake_q, info);
1254 spin_unlock(&info->lock);
1255 wake_up_q(&wake_q);
1256 ret = 0;
1257 }
1258 if (ret == 0) {
1259 ret = msg_ptr->m_ts;
1260
1261 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1262 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1263 ret = -EFAULT;
1264 }
1265 free_msg(msg_ptr);
1266 }
1267out_fput:
1268 fdput(f);
1269out:
1270 return ret;
1271}
1272
1273SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1274 size_t, msg_len, unsigned int, msg_prio,
1275 const struct __kernel_timespec __user *, u_abs_timeout)
1276{
1277 struct timespec64 ts, *p = NULL;
1278 if (u_abs_timeout) {
1279 int res = prepare_timeout(u_abs_timeout, &ts);
1280 if (res)
1281 return res;
1282 p = &ts;
1283 }
1284 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1285}
1286
1287SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1288 size_t, msg_len, unsigned int __user *, u_msg_prio,
1289 const struct __kernel_timespec __user *, u_abs_timeout)
1290{
1291 struct timespec64 ts, *p = NULL;
1292 if (u_abs_timeout) {
1293 int res = prepare_timeout(u_abs_timeout, &ts);
1294 if (res)
1295 return res;
1296 p = &ts;
1297 }
1298 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1299}
1300
1301/*
1302 * Notes: the case when user wants us to deregister (with NULL as pointer)
1303 * and he isn't currently owner of notification, will be silently discarded.
1304 * It isn't explicitly defined in the POSIX.
1305 */
1306static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1307{
1308 int ret;
1309 struct fd f;
1310 struct sock *sock;
1311 struct inode *inode;
1312 struct mqueue_inode_info *info;
1313 struct sk_buff *nc;
1314
1315 audit_mq_notify(mqdes, notification);
1316
1317 nc = NULL;
1318 sock = NULL;
1319 if (notification != NULL) {
1320 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1321 notification->sigev_notify != SIGEV_SIGNAL &&
1322 notification->sigev_notify != SIGEV_THREAD))
1323 return -EINVAL;
1324 if (notification->sigev_notify == SIGEV_SIGNAL &&
1325 !valid_signal(notification->sigev_signo)) {
1326 return -EINVAL;
1327 }
1328 if (notification->sigev_notify == SIGEV_THREAD) {
1329 long timeo;
1330
1331 /* create the notify skb */
1332 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1333 if (!nc)
1334 return -ENOMEM;
1335
1336 if (copy_from_user(nc->data,
1337 notification->sigev_value.sival_ptr,
1338 NOTIFY_COOKIE_LEN)) {
1339 ret = -EFAULT;
1340 goto free_skb;
1341 }
1342
1343 /* TODO: add a header? */
1344 skb_put(nc, NOTIFY_COOKIE_LEN);
1345 /* and attach it to the socket */
1346retry:
1347 f = fdget(notification->sigev_signo);
1348 if (!f.file) {
1349 ret = -EBADF;
1350 goto out;
1351 }
1352 sock = netlink_getsockbyfilp(f.file);
1353 fdput(f);
1354 if (IS_ERR(sock)) {
1355 ret = PTR_ERR(sock);
1356 goto free_skb;
1357 }
1358
1359 timeo = MAX_SCHEDULE_TIMEOUT;
1360 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1361 if (ret == 1) {
1362 sock = NULL;
1363 goto retry;
1364 }
1365 if (ret)
1366 return ret;
1367 }
1368 }
1369
1370 f = fdget(mqdes);
1371 if (!f.file) {
1372 ret = -EBADF;
1373 goto out;
1374 }
1375
1376 inode = file_inode(f.file);
1377 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1378 ret = -EBADF;
1379 goto out_fput;
1380 }
1381 info = MQUEUE_I(inode);
1382
1383 ret = 0;
1384 spin_lock(&info->lock);
1385 if (notification == NULL) {
1386 if (info->notify_owner == task_tgid(current)) {
1387 remove_notification(info);
1388 inode->i_atime = inode->i_ctime = current_time(inode);
1389 }
1390 } else if (info->notify_owner != NULL) {
1391 ret = -EBUSY;
1392 } else {
1393 switch (notification->sigev_notify) {
1394 case SIGEV_NONE:
1395 info->notify.sigev_notify = SIGEV_NONE;
1396 break;
1397 case SIGEV_THREAD:
1398 info->notify_sock = sock;
1399 info->notify_cookie = nc;
1400 sock = NULL;
1401 nc = NULL;
1402 info->notify.sigev_notify = SIGEV_THREAD;
1403 break;
1404 case SIGEV_SIGNAL:
1405 info->notify.sigev_signo = notification->sigev_signo;
1406 info->notify.sigev_value = notification->sigev_value;
1407 info->notify.sigev_notify = SIGEV_SIGNAL;
1408 info->notify_self_exec_id = current->self_exec_id;
1409 break;
1410 }
1411
1412 info->notify_owner = get_pid(task_tgid(current));
1413 info->notify_user_ns = get_user_ns(current_user_ns());
1414 inode->i_atime = inode->i_ctime = current_time(inode);
1415 }
1416 spin_unlock(&info->lock);
1417out_fput:
1418 fdput(f);
1419out:
1420 if (sock)
1421 netlink_detachskb(sock, nc);
1422 else
1423free_skb:
1424 dev_kfree_skb(nc);
1425
1426 return ret;
1427}
1428
1429SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1430 const struct sigevent __user *, u_notification)
1431{
1432 struct sigevent n, *p = NULL;
1433 if (u_notification) {
1434 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1435 return -EFAULT;
1436 p = &n;
1437 }
1438 return do_mq_notify(mqdes, p);
1439}
1440
1441static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1442{
1443 struct fd f;
1444 struct inode *inode;
1445 struct mqueue_inode_info *info;
1446
1447 if (new && (new->mq_flags & (~O_NONBLOCK)))
1448 return -EINVAL;
1449
1450 f = fdget(mqdes);
1451 if (!f.file)
1452 return -EBADF;
1453
1454 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1455 fdput(f);
1456 return -EBADF;
1457 }
1458
1459 inode = file_inode(f.file);
1460 info = MQUEUE_I(inode);
1461
1462 spin_lock(&info->lock);
1463
1464 if (old) {
1465 *old = info->attr;
1466 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1467 }
1468 if (new) {
1469 audit_mq_getsetattr(mqdes, new);
1470 spin_lock(&f.file->f_lock);
1471 if (new->mq_flags & O_NONBLOCK)
1472 f.file->f_flags |= O_NONBLOCK;
1473 else
1474 f.file->f_flags &= ~O_NONBLOCK;
1475 spin_unlock(&f.file->f_lock);
1476
1477 inode->i_atime = inode->i_ctime = current_time(inode);
1478 }
1479
1480 spin_unlock(&info->lock);
1481 fdput(f);
1482 return 0;
1483}
1484
1485SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1486 const struct mq_attr __user *, u_mqstat,
1487 struct mq_attr __user *, u_omqstat)
1488{
1489 int ret;
1490 struct mq_attr mqstat, omqstat;
1491 struct mq_attr *new = NULL, *old = NULL;
1492
1493 if (u_mqstat) {
1494 new = &mqstat;
1495 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1496 return -EFAULT;
1497 }
1498 if (u_omqstat)
1499 old = &omqstat;
1500
1501 ret = do_mq_getsetattr(mqdes, new, old);
1502 if (ret || !old)
1503 return ret;
1504
1505 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1506 return -EFAULT;
1507 return 0;
1508}
1509
1510#ifdef CONFIG_COMPAT
1511
1512struct compat_mq_attr {
1513 compat_long_t mq_flags; /* message queue flags */
1514 compat_long_t mq_maxmsg; /* maximum number of messages */
1515 compat_long_t mq_msgsize; /* maximum message size */
1516 compat_long_t mq_curmsgs; /* number of messages currently queued */
1517 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1518};
1519
1520static inline int get_compat_mq_attr(struct mq_attr *attr,
1521 const struct compat_mq_attr __user *uattr)
1522{
1523 struct compat_mq_attr v;
1524
1525 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1526 return -EFAULT;
1527
1528 memset(attr, 0, sizeof(*attr));
1529 attr->mq_flags = v.mq_flags;
1530 attr->mq_maxmsg = v.mq_maxmsg;
1531 attr->mq_msgsize = v.mq_msgsize;
1532 attr->mq_curmsgs = v.mq_curmsgs;
1533 return 0;
1534}
1535
1536static inline int put_compat_mq_attr(const struct mq_attr *attr,
1537 struct compat_mq_attr __user *uattr)
1538{
1539 struct compat_mq_attr v;
1540
1541 memset(&v, 0, sizeof(v));
1542 v.mq_flags = attr->mq_flags;
1543 v.mq_maxmsg = attr->mq_maxmsg;
1544 v.mq_msgsize = attr->mq_msgsize;
1545 v.mq_curmsgs = attr->mq_curmsgs;
1546 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1547 return -EFAULT;
1548 return 0;
1549}
1550
1551COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1552 int, oflag, compat_mode_t, mode,
1553 struct compat_mq_attr __user *, u_attr)
1554{
1555 struct mq_attr attr, *p = NULL;
1556 if (u_attr && oflag & O_CREAT) {
1557 p = &attr;
1558 if (get_compat_mq_attr(&attr, u_attr))
1559 return -EFAULT;
1560 }
1561 return do_mq_open(u_name, oflag, mode, p);
1562}
1563
1564COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1565 const struct compat_sigevent __user *, u_notification)
1566{
1567 struct sigevent n, *p = NULL;
1568 if (u_notification) {
1569 if (get_compat_sigevent(&n, u_notification))
1570 return -EFAULT;
1571 if (n.sigev_notify == SIGEV_THREAD)
1572 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1573 p = &n;
1574 }
1575 return do_mq_notify(mqdes, p);
1576}
1577
1578COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1579 const struct compat_mq_attr __user *, u_mqstat,
1580 struct compat_mq_attr __user *, u_omqstat)
1581{
1582 int ret;
1583 struct mq_attr mqstat, omqstat;
1584 struct mq_attr *new = NULL, *old = NULL;
1585
1586 if (u_mqstat) {
1587 new = &mqstat;
1588 if (get_compat_mq_attr(new, u_mqstat))
1589 return -EFAULT;
1590 }
1591 if (u_omqstat)
1592 old = &omqstat;
1593
1594 ret = do_mq_getsetattr(mqdes, new, old);
1595 if (ret || !old)
1596 return ret;
1597
1598 if (put_compat_mq_attr(old, u_omqstat))
1599 return -EFAULT;
1600 return 0;
1601}
1602#endif
1603
1604#ifdef CONFIG_COMPAT_32BIT_TIME
1605static int compat_prepare_timeout(const struct old_timespec32 __user *p,
1606 struct timespec64 *ts)
1607{
1608 if (get_old_timespec32(ts, p))
1609 return -EFAULT;
1610 if (!timespec64_valid(ts))
1611 return -EINVAL;
1612 return 0;
1613}
1614
1615SYSCALL_DEFINE5(mq_timedsend_time32, mqd_t, mqdes,
1616 const char __user *, u_msg_ptr,
1617 unsigned int, msg_len, unsigned int, msg_prio,
1618 const struct old_timespec32 __user *, u_abs_timeout)
1619{
1620 struct timespec64 ts, *p = NULL;
1621 if (u_abs_timeout) {
1622 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1623 if (res)
1624 return res;
1625 p = &ts;
1626 }
1627 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1628}
1629
1630SYSCALL_DEFINE5(mq_timedreceive_time32, mqd_t, mqdes,
1631 char __user *, u_msg_ptr,
1632 unsigned int, msg_len, unsigned int __user *, u_msg_prio,
1633 const struct old_timespec32 __user *, u_abs_timeout)
1634{
1635 struct timespec64 ts, *p = NULL;
1636 if (u_abs_timeout) {
1637 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1638 if (res)
1639 return res;
1640 p = &ts;
1641 }
1642 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1643}
1644#endif
1645
1646static const struct inode_operations mqueue_dir_inode_operations = {
1647 .lookup = simple_lookup,
1648 .create = mqueue_create,
1649 .unlink = mqueue_unlink,
1650};
1651
1652static const struct file_operations mqueue_file_operations = {
1653 .flush = mqueue_flush_file,
1654 .poll = mqueue_poll_file,
1655 .read = mqueue_read_file,
1656 .llseek = default_llseek,
1657};
1658
1659static const struct super_operations mqueue_super_ops = {
1660 .alloc_inode = mqueue_alloc_inode,
1661 .free_inode = mqueue_free_inode,
1662 .evict_inode = mqueue_evict_inode,
1663 .statfs = simple_statfs,
1664};
1665
1666static const struct fs_context_operations mqueue_fs_context_ops = {
1667 .free = mqueue_fs_context_free,
1668 .get_tree = mqueue_get_tree,
1669};
1670
1671static struct file_system_type mqueue_fs_type = {
1672 .name = "mqueue",
1673 .init_fs_context = mqueue_init_fs_context,
1674 .kill_sb = kill_litter_super,
1675 .fs_flags = FS_USERNS_MOUNT,
1676};
1677
1678int mq_init_ns(struct ipc_namespace *ns)
1679{
1680 struct vfsmount *m;
1681
1682 ns->mq_queues_count = 0;
1683 ns->mq_queues_max = DFLT_QUEUESMAX;
1684 ns->mq_msg_max = DFLT_MSGMAX;
1685 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1686 ns->mq_msg_default = DFLT_MSG;
1687 ns->mq_msgsize_default = DFLT_MSGSIZE;
1688
1689 m = mq_create_mount(ns);
1690 if (IS_ERR(m))
1691 return PTR_ERR(m);
1692 ns->mq_mnt = m;
1693 return 0;
1694}
1695
1696void mq_clear_sbinfo(struct ipc_namespace *ns)
1697{
1698 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1699}
1700
1701void mq_put_mnt(struct ipc_namespace *ns)
1702{
1703 kern_unmount(ns->mq_mnt);
1704}
1705
1706static int __init init_mqueue_fs(void)
1707{
1708 int error;
1709
1710 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1711 sizeof(struct mqueue_inode_info), 0,
1712 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1713 if (mqueue_inode_cachep == NULL)
1714 return -ENOMEM;
1715
1716 /* ignore failures - they are not fatal */
1717 mq_sysctl_table = mq_register_sysctl_table();
1718
1719 error = register_filesystem(&mqueue_fs_type);
1720 if (error)
1721 goto out_sysctl;
1722
1723 spin_lock_init(&mq_lock);
1724
1725 error = mq_init_ns(&init_ipc_ns);
1726 if (error)
1727 goto out_filesystem;
1728
1729 return 0;
1730
1731out_filesystem:
1732 unregister_filesystem(&mqueue_fs_type);
1733out_sysctl:
1734 if (mq_sysctl_table)
1735 unregister_sysctl_table(mq_sysctl_table);
1736 kmem_cache_destroy(mqueue_inode_cachep);
1737 return error;
1738}
1739
1740device_initcall(init_mqueue_fs);
1/*
2 * POSIX message queues filesystem for Linux.
3 *
4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
5 * Michal Wronski (michal.wronski@gmail.com)
6 *
7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
8 * Lockless receive & send, fd based notify:
9 * Manfred Spraul (manfred@colorfullife.com)
10 *
11 * Audit: George Wilson (ltcgcw@us.ibm.com)
12 *
13 * This file is released under the GPL.
14 */
15
16#include <linux/capability.h>
17#include <linux/init.h>
18#include <linux/pagemap.h>
19#include <linux/file.h>
20#include <linux/mount.h>
21#include <linux/fs_context.h>
22#include <linux/namei.h>
23#include <linux/sysctl.h>
24#include <linux/poll.h>
25#include <linux/mqueue.h>
26#include <linux/msg.h>
27#include <linux/skbuff.h>
28#include <linux/vmalloc.h>
29#include <linux/netlink.h>
30#include <linux/syscalls.h>
31#include <linux/audit.h>
32#include <linux/signal.h>
33#include <linux/mutex.h>
34#include <linux/nsproxy.h>
35#include <linux/pid.h>
36#include <linux/ipc_namespace.h>
37#include <linux/user_namespace.h>
38#include <linux/slab.h>
39#include <linux/sched/wake_q.h>
40#include <linux/sched/signal.h>
41#include <linux/sched/user.h>
42
43#include <net/sock.h>
44#include "util.h"
45
46struct mqueue_fs_context {
47 struct ipc_namespace *ipc_ns;
48};
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
66struct ext_wait_queue { /* queue of sleeping tasks */
67 struct task_struct *task;
68 struct list_head list;
69 struct msg_msg *msg; /* ptr of loaded message */
70 int state; /* one of STATE_* values */
71};
72
73struct mqueue_inode_info {
74 spinlock_t lock;
75 struct inode vfs_inode;
76 wait_queue_head_t wait_q;
77
78 struct rb_root msg_tree;
79 struct rb_node *msg_tree_rightmost;
80 struct posix_msg_tree_node *node_cache;
81 struct mq_attr attr;
82
83 struct sigevent notify;
84 struct pid *notify_owner;
85 struct user_namespace *notify_user_ns;
86 struct user_struct *user; /* user who created, for accounting */
87 struct sock *notify_sock;
88 struct sk_buff *notify_cookie;
89
90 /* for tasks waiting for free space and messages, respectively */
91 struct ext_wait_queue e_wait_q[2];
92
93 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
94};
95
96static struct file_system_type mqueue_fs_type;
97static const struct inode_operations mqueue_dir_inode_operations;
98static const struct file_operations mqueue_file_operations;
99static const struct super_operations mqueue_super_ops;
100static const struct fs_context_operations mqueue_fs_context_ops;
101static void remove_notification(struct mqueue_inode_info *info);
102
103static struct kmem_cache *mqueue_inode_cachep;
104
105static struct ctl_table_header *mq_sysctl_table;
106
107static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
108{
109 return container_of(inode, struct mqueue_inode_info, vfs_inode);
110}
111
112/*
113 * This routine should be called with the mq_lock held.
114 */
115static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
116{
117 return get_ipc_ns(inode->i_sb->s_fs_info);
118}
119
120static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
121{
122 struct ipc_namespace *ns;
123
124 spin_lock(&mq_lock);
125 ns = __get_ns_from_inode(inode);
126 spin_unlock(&mq_lock);
127 return ns;
128}
129
130/* Auxiliary functions to manipulate messages' list */
131static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
132{
133 struct rb_node **p, *parent = NULL;
134 struct posix_msg_tree_node *leaf;
135 bool rightmost = true;
136
137 p = &info->msg_tree.rb_node;
138 while (*p) {
139 parent = *p;
140 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
141
142 if (likely(leaf->priority == msg->m_type))
143 goto insert_msg;
144 else if (msg->m_type < leaf->priority) {
145 p = &(*p)->rb_left;
146 rightmost = false;
147 } else
148 p = &(*p)->rb_right;
149 }
150 if (info->node_cache) {
151 leaf = info->node_cache;
152 info->node_cache = NULL;
153 } else {
154 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
155 if (!leaf)
156 return -ENOMEM;
157 INIT_LIST_HEAD(&leaf->msg_list);
158 }
159 leaf->priority = msg->m_type;
160
161 if (rightmost)
162 info->msg_tree_rightmost = &leaf->rb_node;
163
164 rb_link_node(&leaf->rb_node, parent, p);
165 rb_insert_color(&leaf->rb_node, &info->msg_tree);
166insert_msg:
167 info->attr.mq_curmsgs++;
168 info->qsize += msg->m_ts;
169 list_add_tail(&msg->m_list, &leaf->msg_list);
170 return 0;
171}
172
173static inline void msg_tree_erase(struct posix_msg_tree_node *leaf,
174 struct mqueue_inode_info *info)
175{
176 struct rb_node *node = &leaf->rb_node;
177
178 if (info->msg_tree_rightmost == node)
179 info->msg_tree_rightmost = rb_prev(node);
180
181 rb_erase(node, &info->msg_tree);
182 if (info->node_cache) {
183 kfree(leaf);
184 } else {
185 info->node_cache = leaf;
186 }
187}
188
189static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
190{
191 struct rb_node *parent = NULL;
192 struct posix_msg_tree_node *leaf;
193 struct msg_msg *msg;
194
195try_again:
196 /*
197 * During insert, low priorities go to the left and high to the
198 * right. On receive, we want the highest priorities first, so
199 * walk all the way to the right.
200 */
201 parent = info->msg_tree_rightmost;
202 if (!parent) {
203 if (info->attr.mq_curmsgs) {
204 pr_warn_once("Inconsistency in POSIX message queue, "
205 "no tree element, but supposedly messages "
206 "should exist!\n");
207 info->attr.mq_curmsgs = 0;
208 }
209 return NULL;
210 }
211 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
212 if (unlikely(list_empty(&leaf->msg_list))) {
213 pr_warn_once("Inconsistency in POSIX message queue, "
214 "empty leaf node but we haven't implemented "
215 "lazy leaf delete!\n");
216 msg_tree_erase(leaf, info);
217 goto try_again;
218 } else {
219 msg = list_first_entry(&leaf->msg_list,
220 struct msg_msg, m_list);
221 list_del(&msg->m_list);
222 if (list_empty(&leaf->msg_list)) {
223 msg_tree_erase(leaf, info);
224 }
225 }
226 info->attr.mq_curmsgs--;
227 info->qsize -= msg->m_ts;
228 return msg;
229}
230
231static struct inode *mqueue_get_inode(struct super_block *sb,
232 struct ipc_namespace *ipc_ns, umode_t mode,
233 struct mq_attr *attr)
234{
235 struct user_struct *u = current_user();
236 struct inode *inode;
237 int ret = -ENOMEM;
238
239 inode = new_inode(sb);
240 if (!inode)
241 goto err;
242
243 inode->i_ino = get_next_ino();
244 inode->i_mode = mode;
245 inode->i_uid = current_fsuid();
246 inode->i_gid = current_fsgid();
247 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
248
249 if (S_ISREG(mode)) {
250 struct mqueue_inode_info *info;
251 unsigned long mq_bytes, mq_treesize;
252
253 inode->i_fop = &mqueue_file_operations;
254 inode->i_size = FILENT_SIZE;
255 /* mqueue specific info */
256 info = MQUEUE_I(inode);
257 spin_lock_init(&info->lock);
258 init_waitqueue_head(&info->wait_q);
259 INIT_LIST_HEAD(&info->e_wait_q[0].list);
260 INIT_LIST_HEAD(&info->e_wait_q[1].list);
261 info->notify_owner = NULL;
262 info->notify_user_ns = NULL;
263 info->qsize = 0;
264 info->user = NULL; /* set when all is ok */
265 info->msg_tree = RB_ROOT;
266 info->msg_tree_rightmost = NULL;
267 info->node_cache = NULL;
268 memset(&info->attr, 0, sizeof(info->attr));
269 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
270 ipc_ns->mq_msg_default);
271 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
272 ipc_ns->mq_msgsize_default);
273 if (attr) {
274 info->attr.mq_maxmsg = attr->mq_maxmsg;
275 info->attr.mq_msgsize = attr->mq_msgsize;
276 }
277 /*
278 * We used to allocate a static array of pointers and account
279 * the size of that array as well as one msg_msg struct per
280 * possible message into the queue size. That's no longer
281 * accurate as the queue is now an rbtree and will grow and
282 * shrink depending on usage patterns. We can, however, still
283 * account one msg_msg struct per message, but the nodes are
284 * allocated depending on priority usage, and most programs
285 * only use one, or a handful, of priorities. However, since
286 * this is pinned memory, we need to assume worst case, so
287 * that means the min(mq_maxmsg, max_priorities) * struct
288 * posix_msg_tree_node.
289 */
290
291 ret = -EINVAL;
292 if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
293 goto out_inode;
294 if (capable(CAP_SYS_RESOURCE)) {
295 if (info->attr.mq_maxmsg > HARD_MSGMAX ||
296 info->attr.mq_msgsize > HARD_MSGSIZEMAX)
297 goto out_inode;
298 } else {
299 if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
300 info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
301 goto out_inode;
302 }
303 ret = -EOVERFLOW;
304 /* check for overflow */
305 if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
306 goto out_inode;
307 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
308 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
309 sizeof(struct posix_msg_tree_node);
310 mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
311 if (mq_bytes + mq_treesize < mq_bytes)
312 goto out_inode;
313 mq_bytes += mq_treesize;
314 spin_lock(&mq_lock);
315 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
316 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
317 spin_unlock(&mq_lock);
318 /* mqueue_evict_inode() releases info->messages */
319 ret = -EMFILE;
320 goto out_inode;
321 }
322 u->mq_bytes += mq_bytes;
323 spin_unlock(&mq_lock);
324
325 /* all is ok */
326 info->user = get_uid(u);
327 } else if (S_ISDIR(mode)) {
328 inc_nlink(inode);
329 /* Some things misbehave if size == 0 on a directory */
330 inode->i_size = 2 * DIRENT_SIZE;
331 inode->i_op = &mqueue_dir_inode_operations;
332 inode->i_fop = &simple_dir_operations;
333 }
334
335 return inode;
336out_inode:
337 iput(inode);
338err:
339 return ERR_PTR(ret);
340}
341
342static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc)
343{
344 struct inode *inode;
345 struct ipc_namespace *ns = sb->s_fs_info;
346
347 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
348 sb->s_blocksize = PAGE_SIZE;
349 sb->s_blocksize_bits = PAGE_SHIFT;
350 sb->s_magic = MQUEUE_MAGIC;
351 sb->s_op = &mqueue_super_ops;
352
353 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
354 if (IS_ERR(inode))
355 return PTR_ERR(inode);
356
357 sb->s_root = d_make_root(inode);
358 if (!sb->s_root)
359 return -ENOMEM;
360 return 0;
361}
362
363static int mqueue_get_tree(struct fs_context *fc)
364{
365 struct mqueue_fs_context *ctx = fc->fs_private;
366
367 return get_tree_keyed(fc, mqueue_fill_super, ctx->ipc_ns);
368}
369
370static void mqueue_fs_context_free(struct fs_context *fc)
371{
372 struct mqueue_fs_context *ctx = fc->fs_private;
373
374 put_ipc_ns(ctx->ipc_ns);
375 kfree(ctx);
376}
377
378static int mqueue_init_fs_context(struct fs_context *fc)
379{
380 struct mqueue_fs_context *ctx;
381
382 ctx = kzalloc(sizeof(struct mqueue_fs_context), GFP_KERNEL);
383 if (!ctx)
384 return -ENOMEM;
385
386 ctx->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
387 put_user_ns(fc->user_ns);
388 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
389 fc->fs_private = ctx;
390 fc->ops = &mqueue_fs_context_ops;
391 return 0;
392}
393
394static struct vfsmount *mq_create_mount(struct ipc_namespace *ns)
395{
396 struct mqueue_fs_context *ctx;
397 struct fs_context *fc;
398 struct vfsmount *mnt;
399
400 fc = fs_context_for_mount(&mqueue_fs_type, SB_KERNMOUNT);
401 if (IS_ERR(fc))
402 return ERR_CAST(fc);
403
404 ctx = fc->fs_private;
405 put_ipc_ns(ctx->ipc_ns);
406 ctx->ipc_ns = get_ipc_ns(ns);
407 put_user_ns(fc->user_ns);
408 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
409
410 mnt = fc_mount(fc);
411 put_fs_context(fc);
412 return mnt;
413}
414
415static void init_once(void *foo)
416{
417 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
418
419 inode_init_once(&p->vfs_inode);
420}
421
422static struct inode *mqueue_alloc_inode(struct super_block *sb)
423{
424 struct mqueue_inode_info *ei;
425
426 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
427 if (!ei)
428 return NULL;
429 return &ei->vfs_inode;
430}
431
432static void mqueue_free_inode(struct inode *inode)
433{
434 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
435}
436
437static void mqueue_evict_inode(struct inode *inode)
438{
439 struct mqueue_inode_info *info;
440 struct user_struct *user;
441 struct ipc_namespace *ipc_ns;
442 struct msg_msg *msg, *nmsg;
443 LIST_HEAD(tmp_msg);
444
445 clear_inode(inode);
446
447 if (S_ISDIR(inode->i_mode))
448 return;
449
450 ipc_ns = get_ns_from_inode(inode);
451 info = MQUEUE_I(inode);
452 spin_lock(&info->lock);
453 while ((msg = msg_get(info)) != NULL)
454 list_add_tail(&msg->m_list, &tmp_msg);
455 kfree(info->node_cache);
456 spin_unlock(&info->lock);
457
458 list_for_each_entry_safe(msg, nmsg, &tmp_msg, m_list) {
459 list_del(&msg->m_list);
460 free_msg(msg);
461 }
462
463 user = info->user;
464 if (user) {
465 unsigned long mq_bytes, mq_treesize;
466
467 /* Total amount of bytes accounted for the mqueue */
468 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
469 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
470 sizeof(struct posix_msg_tree_node);
471
472 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
473 info->attr.mq_msgsize);
474
475 spin_lock(&mq_lock);
476 user->mq_bytes -= mq_bytes;
477 /*
478 * get_ns_from_inode() ensures that the
479 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
480 * to which we now hold a reference, or it is NULL.
481 * We can't put it here under mq_lock, though.
482 */
483 if (ipc_ns)
484 ipc_ns->mq_queues_count--;
485 spin_unlock(&mq_lock);
486 free_uid(user);
487 }
488 if (ipc_ns)
489 put_ipc_ns(ipc_ns);
490}
491
492static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
493{
494 struct inode *dir = dentry->d_parent->d_inode;
495 struct inode *inode;
496 struct mq_attr *attr = arg;
497 int error;
498 struct ipc_namespace *ipc_ns;
499
500 spin_lock(&mq_lock);
501 ipc_ns = __get_ns_from_inode(dir);
502 if (!ipc_ns) {
503 error = -EACCES;
504 goto out_unlock;
505 }
506
507 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
508 !capable(CAP_SYS_RESOURCE)) {
509 error = -ENOSPC;
510 goto out_unlock;
511 }
512 ipc_ns->mq_queues_count++;
513 spin_unlock(&mq_lock);
514
515 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
516 if (IS_ERR(inode)) {
517 error = PTR_ERR(inode);
518 spin_lock(&mq_lock);
519 ipc_ns->mq_queues_count--;
520 goto out_unlock;
521 }
522
523 put_ipc_ns(ipc_ns);
524 dir->i_size += DIRENT_SIZE;
525 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
526
527 d_instantiate(dentry, inode);
528 dget(dentry);
529 return 0;
530out_unlock:
531 spin_unlock(&mq_lock);
532 if (ipc_ns)
533 put_ipc_ns(ipc_ns);
534 return error;
535}
536
537static int mqueue_create(struct inode *dir, struct dentry *dentry,
538 umode_t mode, bool excl)
539{
540 return mqueue_create_attr(dentry, mode, NULL);
541}
542
543static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
544{
545 struct inode *inode = d_inode(dentry);
546
547 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
548 dir->i_size -= DIRENT_SIZE;
549 drop_nlink(inode);
550 dput(dentry);
551 return 0;
552}
553
554/*
555* This is routine for system read from queue file.
556* To avoid mess with doing here some sort of mq_receive we allow
557* to read only queue size & notification info (the only values
558* that are interesting from user point of view and aren't accessible
559* through std routines)
560*/
561static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
562 size_t count, loff_t *off)
563{
564 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
565 char buffer[FILENT_SIZE];
566 ssize_t ret;
567
568 spin_lock(&info->lock);
569 snprintf(buffer, sizeof(buffer),
570 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
571 info->qsize,
572 info->notify_owner ? info->notify.sigev_notify : 0,
573 (info->notify_owner &&
574 info->notify.sigev_notify == SIGEV_SIGNAL) ?
575 info->notify.sigev_signo : 0,
576 pid_vnr(info->notify_owner));
577 spin_unlock(&info->lock);
578 buffer[sizeof(buffer)-1] = '\0';
579
580 ret = simple_read_from_buffer(u_data, count, off, buffer,
581 strlen(buffer));
582 if (ret <= 0)
583 return ret;
584
585 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
586 return ret;
587}
588
589static int mqueue_flush_file(struct file *filp, fl_owner_t id)
590{
591 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
592
593 spin_lock(&info->lock);
594 if (task_tgid(current) == info->notify_owner)
595 remove_notification(info);
596
597 spin_unlock(&info->lock);
598 return 0;
599}
600
601static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
602{
603 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
604 __poll_t retval = 0;
605
606 poll_wait(filp, &info->wait_q, poll_tab);
607
608 spin_lock(&info->lock);
609 if (info->attr.mq_curmsgs)
610 retval = EPOLLIN | EPOLLRDNORM;
611
612 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
613 retval |= EPOLLOUT | EPOLLWRNORM;
614 spin_unlock(&info->lock);
615
616 return retval;
617}
618
619/* Adds current to info->e_wait_q[sr] before element with smaller prio */
620static void wq_add(struct mqueue_inode_info *info, int sr,
621 struct ext_wait_queue *ewp)
622{
623 struct ext_wait_queue *walk;
624
625 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
626 if (walk->task->prio <= current->prio) {
627 list_add_tail(&ewp->list, &walk->list);
628 return;
629 }
630 }
631 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
632}
633
634/*
635 * Puts current task to sleep. Caller must hold queue lock. After return
636 * lock isn't held.
637 * sr: SEND or RECV
638 */
639static int wq_sleep(struct mqueue_inode_info *info, int sr,
640 ktime_t *timeout, struct ext_wait_queue *ewp)
641 __releases(&info->lock)
642{
643 int retval;
644 signed long time;
645
646 wq_add(info, sr, ewp);
647
648 for (;;) {
649 __set_current_state(TASK_INTERRUPTIBLE);
650
651 spin_unlock(&info->lock);
652 time = schedule_hrtimeout_range_clock(timeout, 0,
653 HRTIMER_MODE_ABS, CLOCK_REALTIME);
654
655 if (ewp->state == STATE_READY) {
656 retval = 0;
657 goto out;
658 }
659 spin_lock(&info->lock);
660 if (ewp->state == STATE_READY) {
661 retval = 0;
662 goto out_unlock;
663 }
664 if (signal_pending(current)) {
665 retval = -ERESTARTSYS;
666 break;
667 }
668 if (time == 0) {
669 retval = -ETIMEDOUT;
670 break;
671 }
672 }
673 list_del(&ewp->list);
674out_unlock:
675 spin_unlock(&info->lock);
676out:
677 return retval;
678}
679
680/*
681 * Returns waiting task that should be serviced first or NULL if none exists
682 */
683static struct ext_wait_queue *wq_get_first_waiter(
684 struct mqueue_inode_info *info, int sr)
685{
686 struct list_head *ptr;
687
688 ptr = info->e_wait_q[sr].list.prev;
689 if (ptr == &info->e_wait_q[sr].list)
690 return NULL;
691 return list_entry(ptr, struct ext_wait_queue, list);
692}
693
694
695static inline void set_cookie(struct sk_buff *skb, char code)
696{
697 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
698}
699
700/*
701 * The next function is only to split too long sys_mq_timedsend
702 */
703static void __do_notify(struct mqueue_inode_info *info)
704{
705 /* notification
706 * invoked when there is registered process and there isn't process
707 * waiting synchronously for message AND state of queue changed from
708 * empty to not empty. Here we are sure that no one is waiting
709 * synchronously. */
710 if (info->notify_owner &&
711 info->attr.mq_curmsgs == 1) {
712 struct kernel_siginfo sig_i;
713 switch (info->notify.sigev_notify) {
714 case SIGEV_NONE:
715 break;
716 case SIGEV_SIGNAL:
717 /* sends signal */
718
719 clear_siginfo(&sig_i);
720 sig_i.si_signo = info->notify.sigev_signo;
721 sig_i.si_errno = 0;
722 sig_i.si_code = SI_MESGQ;
723 sig_i.si_value = info->notify.sigev_value;
724 /* map current pid/uid into info->owner's namespaces */
725 rcu_read_lock();
726 sig_i.si_pid = task_tgid_nr_ns(current,
727 ns_of_pid(info->notify_owner));
728 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
729 rcu_read_unlock();
730
731 kill_pid_info(info->notify.sigev_signo,
732 &sig_i, info->notify_owner);
733 break;
734 case SIGEV_THREAD:
735 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
736 netlink_sendskb(info->notify_sock, info->notify_cookie);
737 break;
738 }
739 /* after notification unregisters process */
740 put_pid(info->notify_owner);
741 put_user_ns(info->notify_user_ns);
742 info->notify_owner = NULL;
743 info->notify_user_ns = NULL;
744 }
745 wake_up(&info->wait_q);
746}
747
748static int prepare_timeout(const struct __kernel_timespec __user *u_abs_timeout,
749 struct timespec64 *ts)
750{
751 if (get_timespec64(ts, u_abs_timeout))
752 return -EFAULT;
753 if (!timespec64_valid(ts))
754 return -EINVAL;
755 return 0;
756}
757
758static void remove_notification(struct mqueue_inode_info *info)
759{
760 if (info->notify_owner != NULL &&
761 info->notify.sigev_notify == SIGEV_THREAD) {
762 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
763 netlink_sendskb(info->notify_sock, info->notify_cookie);
764 }
765 put_pid(info->notify_owner);
766 put_user_ns(info->notify_user_ns);
767 info->notify_owner = NULL;
768 info->notify_user_ns = NULL;
769}
770
771static int prepare_open(struct dentry *dentry, int oflag, int ro,
772 umode_t mode, struct filename *name,
773 struct mq_attr *attr)
774{
775 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
776 MAY_READ | MAY_WRITE };
777 int acc;
778
779 if (d_really_is_negative(dentry)) {
780 if (!(oflag & O_CREAT))
781 return -ENOENT;
782 if (ro)
783 return ro;
784 audit_inode_parent_hidden(name, dentry->d_parent);
785 return vfs_mkobj(dentry, mode & ~current_umask(),
786 mqueue_create_attr, attr);
787 }
788 /* it already existed */
789 audit_inode(name, dentry, 0);
790 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
791 return -EEXIST;
792 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
793 return -EINVAL;
794 acc = oflag2acc[oflag & O_ACCMODE];
795 return inode_permission(d_inode(dentry), acc);
796}
797
798static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
799 struct mq_attr *attr)
800{
801 struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
802 struct dentry *root = mnt->mnt_root;
803 struct filename *name;
804 struct path path;
805 int fd, error;
806 int ro;
807
808 audit_mq_open(oflag, mode, attr);
809
810 if (IS_ERR(name = getname(u_name)))
811 return PTR_ERR(name);
812
813 fd = get_unused_fd_flags(O_CLOEXEC);
814 if (fd < 0)
815 goto out_putname;
816
817 ro = mnt_want_write(mnt); /* we'll drop it in any case */
818 inode_lock(d_inode(root));
819 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
820 if (IS_ERR(path.dentry)) {
821 error = PTR_ERR(path.dentry);
822 goto out_putfd;
823 }
824 path.mnt = mntget(mnt);
825 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
826 if (!error) {
827 struct file *file = dentry_open(&path, oflag, current_cred());
828 if (!IS_ERR(file))
829 fd_install(fd, file);
830 else
831 error = PTR_ERR(file);
832 }
833 path_put(&path);
834out_putfd:
835 if (error) {
836 put_unused_fd(fd);
837 fd = error;
838 }
839 inode_unlock(d_inode(root));
840 if (!ro)
841 mnt_drop_write(mnt);
842out_putname:
843 putname(name);
844 return fd;
845}
846
847SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
848 struct mq_attr __user *, u_attr)
849{
850 struct mq_attr attr;
851 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
852 return -EFAULT;
853
854 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
855}
856
857SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
858{
859 int err;
860 struct filename *name;
861 struct dentry *dentry;
862 struct inode *inode = NULL;
863 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
864 struct vfsmount *mnt = ipc_ns->mq_mnt;
865
866 name = getname(u_name);
867 if (IS_ERR(name))
868 return PTR_ERR(name);
869
870 audit_inode_parent_hidden(name, mnt->mnt_root);
871 err = mnt_want_write(mnt);
872 if (err)
873 goto out_name;
874 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
875 dentry = lookup_one_len(name->name, mnt->mnt_root,
876 strlen(name->name));
877 if (IS_ERR(dentry)) {
878 err = PTR_ERR(dentry);
879 goto out_unlock;
880 }
881
882 inode = d_inode(dentry);
883 if (!inode) {
884 err = -ENOENT;
885 } else {
886 ihold(inode);
887 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
888 }
889 dput(dentry);
890
891out_unlock:
892 inode_unlock(d_inode(mnt->mnt_root));
893 if (inode)
894 iput(inode);
895 mnt_drop_write(mnt);
896out_name:
897 putname(name);
898
899 return err;
900}
901
902/* Pipelined send and receive functions.
903 *
904 * If a receiver finds no waiting message, then it registers itself in the
905 * list of waiting receivers. A sender checks that list before adding the new
906 * message into the message array. If there is a waiting receiver, then it
907 * bypasses the message array and directly hands the message over to the
908 * receiver. The receiver accepts the message and returns without grabbing the
909 * queue spinlock:
910 *
911 * - Set pointer to message.
912 * - Queue the receiver task for later wakeup (without the info->lock).
913 * - Update its state to STATE_READY. Now the receiver can continue.
914 * - Wake up the process after the lock is dropped. Should the process wake up
915 * before this wakeup (due to a timeout or a signal) it will either see
916 * STATE_READY and continue or acquire the lock to check the state again.
917 *
918 * The same algorithm is used for senders.
919 */
920
921/* pipelined_send() - send a message directly to the task waiting in
922 * sys_mq_timedreceive() (without inserting message into a queue).
923 */
924static inline void pipelined_send(struct wake_q_head *wake_q,
925 struct mqueue_inode_info *info,
926 struct msg_msg *message,
927 struct ext_wait_queue *receiver)
928{
929 receiver->msg = message;
930 list_del(&receiver->list);
931 wake_q_add(wake_q, receiver->task);
932 /*
933 * Rely on the implicit cmpxchg barrier from wake_q_add such
934 * that we can ensure that updating receiver->state is the last
935 * write operation: As once set, the receiver can continue,
936 * and if we don't have the reference count from the wake_q,
937 * yet, at that point we can later have a use-after-free
938 * condition and bogus wakeup.
939 */
940 receiver->state = STATE_READY;
941}
942
943/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
944 * gets its message and put to the queue (we have one free place for sure). */
945static inline void pipelined_receive(struct wake_q_head *wake_q,
946 struct mqueue_inode_info *info)
947{
948 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
949
950 if (!sender) {
951 /* for poll */
952 wake_up_interruptible(&info->wait_q);
953 return;
954 }
955 if (msg_insert(sender->msg, info))
956 return;
957
958 list_del(&sender->list);
959 wake_q_add(wake_q, sender->task);
960 sender->state = STATE_READY;
961}
962
963static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
964 size_t msg_len, unsigned int msg_prio,
965 struct timespec64 *ts)
966{
967 struct fd f;
968 struct inode *inode;
969 struct ext_wait_queue wait;
970 struct ext_wait_queue *receiver;
971 struct msg_msg *msg_ptr;
972 struct mqueue_inode_info *info;
973 ktime_t expires, *timeout = NULL;
974 struct posix_msg_tree_node *new_leaf = NULL;
975 int ret = 0;
976 DEFINE_WAKE_Q(wake_q);
977
978 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
979 return -EINVAL;
980
981 if (ts) {
982 expires = timespec64_to_ktime(*ts);
983 timeout = &expires;
984 }
985
986 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
987
988 f = fdget(mqdes);
989 if (unlikely(!f.file)) {
990 ret = -EBADF;
991 goto out;
992 }
993
994 inode = file_inode(f.file);
995 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
996 ret = -EBADF;
997 goto out_fput;
998 }
999 info = MQUEUE_I(inode);
1000 audit_file(f.file);
1001
1002 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
1003 ret = -EBADF;
1004 goto out_fput;
1005 }
1006
1007 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1008 ret = -EMSGSIZE;
1009 goto out_fput;
1010 }
1011
1012 /* First try to allocate memory, before doing anything with
1013 * existing queues. */
1014 msg_ptr = load_msg(u_msg_ptr, msg_len);
1015 if (IS_ERR(msg_ptr)) {
1016 ret = PTR_ERR(msg_ptr);
1017 goto out_fput;
1018 }
1019 msg_ptr->m_ts = msg_len;
1020 msg_ptr->m_type = msg_prio;
1021
1022 /*
1023 * msg_insert really wants us to have a valid, spare node struct so
1024 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1025 * fall back to that if necessary.
1026 */
1027 if (!info->node_cache)
1028 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1029
1030 spin_lock(&info->lock);
1031
1032 if (!info->node_cache && new_leaf) {
1033 /* Save our speculative allocation into the cache */
1034 INIT_LIST_HEAD(&new_leaf->msg_list);
1035 info->node_cache = new_leaf;
1036 new_leaf = NULL;
1037 } else {
1038 kfree(new_leaf);
1039 }
1040
1041 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1042 if (f.file->f_flags & O_NONBLOCK) {
1043 ret = -EAGAIN;
1044 } else {
1045 wait.task = current;
1046 wait.msg = (void *) msg_ptr;
1047 wait.state = STATE_NONE;
1048 ret = wq_sleep(info, SEND, timeout, &wait);
1049 /*
1050 * wq_sleep must be called with info->lock held, and
1051 * returns with the lock released
1052 */
1053 goto out_free;
1054 }
1055 } else {
1056 receiver = wq_get_first_waiter(info, RECV);
1057 if (receiver) {
1058 pipelined_send(&wake_q, info, msg_ptr, receiver);
1059 } else {
1060 /* adds message to the queue */
1061 ret = msg_insert(msg_ptr, info);
1062 if (ret)
1063 goto out_unlock;
1064 __do_notify(info);
1065 }
1066 inode->i_atime = inode->i_mtime = inode->i_ctime =
1067 current_time(inode);
1068 }
1069out_unlock:
1070 spin_unlock(&info->lock);
1071 wake_up_q(&wake_q);
1072out_free:
1073 if (ret)
1074 free_msg(msg_ptr);
1075out_fput:
1076 fdput(f);
1077out:
1078 return ret;
1079}
1080
1081static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1082 size_t msg_len, unsigned int __user *u_msg_prio,
1083 struct timespec64 *ts)
1084{
1085 ssize_t ret;
1086 struct msg_msg *msg_ptr;
1087 struct fd f;
1088 struct inode *inode;
1089 struct mqueue_inode_info *info;
1090 struct ext_wait_queue wait;
1091 ktime_t expires, *timeout = NULL;
1092 struct posix_msg_tree_node *new_leaf = NULL;
1093
1094 if (ts) {
1095 expires = timespec64_to_ktime(*ts);
1096 timeout = &expires;
1097 }
1098
1099 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1100
1101 f = fdget(mqdes);
1102 if (unlikely(!f.file)) {
1103 ret = -EBADF;
1104 goto out;
1105 }
1106
1107 inode = file_inode(f.file);
1108 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1109 ret = -EBADF;
1110 goto out_fput;
1111 }
1112 info = MQUEUE_I(inode);
1113 audit_file(f.file);
1114
1115 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1116 ret = -EBADF;
1117 goto out_fput;
1118 }
1119
1120 /* checks if buffer is big enough */
1121 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1122 ret = -EMSGSIZE;
1123 goto out_fput;
1124 }
1125
1126 /*
1127 * msg_insert really wants us to have a valid, spare node struct so
1128 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1129 * fall back to that if necessary.
1130 */
1131 if (!info->node_cache)
1132 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1133
1134 spin_lock(&info->lock);
1135
1136 if (!info->node_cache && new_leaf) {
1137 /* Save our speculative allocation into the cache */
1138 INIT_LIST_HEAD(&new_leaf->msg_list);
1139 info->node_cache = new_leaf;
1140 } else {
1141 kfree(new_leaf);
1142 }
1143
1144 if (info->attr.mq_curmsgs == 0) {
1145 if (f.file->f_flags & O_NONBLOCK) {
1146 spin_unlock(&info->lock);
1147 ret = -EAGAIN;
1148 } else {
1149 wait.task = current;
1150 wait.state = STATE_NONE;
1151 ret = wq_sleep(info, RECV, timeout, &wait);
1152 msg_ptr = wait.msg;
1153 }
1154 } else {
1155 DEFINE_WAKE_Q(wake_q);
1156
1157 msg_ptr = msg_get(info);
1158
1159 inode->i_atime = inode->i_mtime = inode->i_ctime =
1160 current_time(inode);
1161
1162 /* There is now free space in queue. */
1163 pipelined_receive(&wake_q, info);
1164 spin_unlock(&info->lock);
1165 wake_up_q(&wake_q);
1166 ret = 0;
1167 }
1168 if (ret == 0) {
1169 ret = msg_ptr->m_ts;
1170
1171 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1172 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1173 ret = -EFAULT;
1174 }
1175 free_msg(msg_ptr);
1176 }
1177out_fput:
1178 fdput(f);
1179out:
1180 return ret;
1181}
1182
1183SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1184 size_t, msg_len, unsigned int, msg_prio,
1185 const struct __kernel_timespec __user *, u_abs_timeout)
1186{
1187 struct timespec64 ts, *p = NULL;
1188 if (u_abs_timeout) {
1189 int res = prepare_timeout(u_abs_timeout, &ts);
1190 if (res)
1191 return res;
1192 p = &ts;
1193 }
1194 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1195}
1196
1197SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1198 size_t, msg_len, unsigned int __user *, u_msg_prio,
1199 const struct __kernel_timespec __user *, u_abs_timeout)
1200{
1201 struct timespec64 ts, *p = NULL;
1202 if (u_abs_timeout) {
1203 int res = prepare_timeout(u_abs_timeout, &ts);
1204 if (res)
1205 return res;
1206 p = &ts;
1207 }
1208 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1209}
1210
1211/*
1212 * Notes: the case when user wants us to deregister (with NULL as pointer)
1213 * and he isn't currently owner of notification, will be silently discarded.
1214 * It isn't explicitly defined in the POSIX.
1215 */
1216static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1217{
1218 int ret;
1219 struct fd f;
1220 struct sock *sock;
1221 struct inode *inode;
1222 struct mqueue_inode_info *info;
1223 struct sk_buff *nc;
1224
1225 audit_mq_notify(mqdes, notification);
1226
1227 nc = NULL;
1228 sock = NULL;
1229 if (notification != NULL) {
1230 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1231 notification->sigev_notify != SIGEV_SIGNAL &&
1232 notification->sigev_notify != SIGEV_THREAD))
1233 return -EINVAL;
1234 if (notification->sigev_notify == SIGEV_SIGNAL &&
1235 !valid_signal(notification->sigev_signo)) {
1236 return -EINVAL;
1237 }
1238 if (notification->sigev_notify == SIGEV_THREAD) {
1239 long timeo;
1240
1241 /* create the notify skb */
1242 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1243 if (!nc)
1244 return -ENOMEM;
1245
1246 if (copy_from_user(nc->data,
1247 notification->sigev_value.sival_ptr,
1248 NOTIFY_COOKIE_LEN)) {
1249 ret = -EFAULT;
1250 goto free_skb;
1251 }
1252
1253 /* TODO: add a header? */
1254 skb_put(nc, NOTIFY_COOKIE_LEN);
1255 /* and attach it to the socket */
1256retry:
1257 f = fdget(notification->sigev_signo);
1258 if (!f.file) {
1259 ret = -EBADF;
1260 goto out;
1261 }
1262 sock = netlink_getsockbyfilp(f.file);
1263 fdput(f);
1264 if (IS_ERR(sock)) {
1265 ret = PTR_ERR(sock);
1266 goto free_skb;
1267 }
1268
1269 timeo = MAX_SCHEDULE_TIMEOUT;
1270 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1271 if (ret == 1) {
1272 sock = NULL;
1273 goto retry;
1274 }
1275 if (ret)
1276 return ret;
1277 }
1278 }
1279
1280 f = fdget(mqdes);
1281 if (!f.file) {
1282 ret = -EBADF;
1283 goto out;
1284 }
1285
1286 inode = file_inode(f.file);
1287 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1288 ret = -EBADF;
1289 goto out_fput;
1290 }
1291 info = MQUEUE_I(inode);
1292
1293 ret = 0;
1294 spin_lock(&info->lock);
1295 if (notification == NULL) {
1296 if (info->notify_owner == task_tgid(current)) {
1297 remove_notification(info);
1298 inode->i_atime = inode->i_ctime = current_time(inode);
1299 }
1300 } else if (info->notify_owner != NULL) {
1301 ret = -EBUSY;
1302 } else {
1303 switch (notification->sigev_notify) {
1304 case SIGEV_NONE:
1305 info->notify.sigev_notify = SIGEV_NONE;
1306 break;
1307 case SIGEV_THREAD:
1308 info->notify_sock = sock;
1309 info->notify_cookie = nc;
1310 sock = NULL;
1311 nc = NULL;
1312 info->notify.sigev_notify = SIGEV_THREAD;
1313 break;
1314 case SIGEV_SIGNAL:
1315 info->notify.sigev_signo = notification->sigev_signo;
1316 info->notify.sigev_value = notification->sigev_value;
1317 info->notify.sigev_notify = SIGEV_SIGNAL;
1318 break;
1319 }
1320
1321 info->notify_owner = get_pid(task_tgid(current));
1322 info->notify_user_ns = get_user_ns(current_user_ns());
1323 inode->i_atime = inode->i_ctime = current_time(inode);
1324 }
1325 spin_unlock(&info->lock);
1326out_fput:
1327 fdput(f);
1328out:
1329 if (sock)
1330 netlink_detachskb(sock, nc);
1331 else
1332free_skb:
1333 dev_kfree_skb(nc);
1334
1335 return ret;
1336}
1337
1338SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1339 const struct sigevent __user *, u_notification)
1340{
1341 struct sigevent n, *p = NULL;
1342 if (u_notification) {
1343 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1344 return -EFAULT;
1345 p = &n;
1346 }
1347 return do_mq_notify(mqdes, p);
1348}
1349
1350static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1351{
1352 struct fd f;
1353 struct inode *inode;
1354 struct mqueue_inode_info *info;
1355
1356 if (new && (new->mq_flags & (~O_NONBLOCK)))
1357 return -EINVAL;
1358
1359 f = fdget(mqdes);
1360 if (!f.file)
1361 return -EBADF;
1362
1363 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1364 fdput(f);
1365 return -EBADF;
1366 }
1367
1368 inode = file_inode(f.file);
1369 info = MQUEUE_I(inode);
1370
1371 spin_lock(&info->lock);
1372
1373 if (old) {
1374 *old = info->attr;
1375 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1376 }
1377 if (new) {
1378 audit_mq_getsetattr(mqdes, new);
1379 spin_lock(&f.file->f_lock);
1380 if (new->mq_flags & O_NONBLOCK)
1381 f.file->f_flags |= O_NONBLOCK;
1382 else
1383 f.file->f_flags &= ~O_NONBLOCK;
1384 spin_unlock(&f.file->f_lock);
1385
1386 inode->i_atime = inode->i_ctime = current_time(inode);
1387 }
1388
1389 spin_unlock(&info->lock);
1390 fdput(f);
1391 return 0;
1392}
1393
1394SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1395 const struct mq_attr __user *, u_mqstat,
1396 struct mq_attr __user *, u_omqstat)
1397{
1398 int ret;
1399 struct mq_attr mqstat, omqstat;
1400 struct mq_attr *new = NULL, *old = NULL;
1401
1402 if (u_mqstat) {
1403 new = &mqstat;
1404 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1405 return -EFAULT;
1406 }
1407 if (u_omqstat)
1408 old = &omqstat;
1409
1410 ret = do_mq_getsetattr(mqdes, new, old);
1411 if (ret || !old)
1412 return ret;
1413
1414 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1415 return -EFAULT;
1416 return 0;
1417}
1418
1419#ifdef CONFIG_COMPAT
1420
1421struct compat_mq_attr {
1422 compat_long_t mq_flags; /* message queue flags */
1423 compat_long_t mq_maxmsg; /* maximum number of messages */
1424 compat_long_t mq_msgsize; /* maximum message size */
1425 compat_long_t mq_curmsgs; /* number of messages currently queued */
1426 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1427};
1428
1429static inline int get_compat_mq_attr(struct mq_attr *attr,
1430 const struct compat_mq_attr __user *uattr)
1431{
1432 struct compat_mq_attr v;
1433
1434 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1435 return -EFAULT;
1436
1437 memset(attr, 0, sizeof(*attr));
1438 attr->mq_flags = v.mq_flags;
1439 attr->mq_maxmsg = v.mq_maxmsg;
1440 attr->mq_msgsize = v.mq_msgsize;
1441 attr->mq_curmsgs = v.mq_curmsgs;
1442 return 0;
1443}
1444
1445static inline int put_compat_mq_attr(const struct mq_attr *attr,
1446 struct compat_mq_attr __user *uattr)
1447{
1448 struct compat_mq_attr v;
1449
1450 memset(&v, 0, sizeof(v));
1451 v.mq_flags = attr->mq_flags;
1452 v.mq_maxmsg = attr->mq_maxmsg;
1453 v.mq_msgsize = attr->mq_msgsize;
1454 v.mq_curmsgs = attr->mq_curmsgs;
1455 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1456 return -EFAULT;
1457 return 0;
1458}
1459
1460COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1461 int, oflag, compat_mode_t, mode,
1462 struct compat_mq_attr __user *, u_attr)
1463{
1464 struct mq_attr attr, *p = NULL;
1465 if (u_attr && oflag & O_CREAT) {
1466 p = &attr;
1467 if (get_compat_mq_attr(&attr, u_attr))
1468 return -EFAULT;
1469 }
1470 return do_mq_open(u_name, oflag, mode, p);
1471}
1472
1473COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1474 const struct compat_sigevent __user *, u_notification)
1475{
1476 struct sigevent n, *p = NULL;
1477 if (u_notification) {
1478 if (get_compat_sigevent(&n, u_notification))
1479 return -EFAULT;
1480 if (n.sigev_notify == SIGEV_THREAD)
1481 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1482 p = &n;
1483 }
1484 return do_mq_notify(mqdes, p);
1485}
1486
1487COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1488 const struct compat_mq_attr __user *, u_mqstat,
1489 struct compat_mq_attr __user *, u_omqstat)
1490{
1491 int ret;
1492 struct mq_attr mqstat, omqstat;
1493 struct mq_attr *new = NULL, *old = NULL;
1494
1495 if (u_mqstat) {
1496 new = &mqstat;
1497 if (get_compat_mq_attr(new, u_mqstat))
1498 return -EFAULT;
1499 }
1500 if (u_omqstat)
1501 old = &omqstat;
1502
1503 ret = do_mq_getsetattr(mqdes, new, old);
1504 if (ret || !old)
1505 return ret;
1506
1507 if (put_compat_mq_attr(old, u_omqstat))
1508 return -EFAULT;
1509 return 0;
1510}
1511#endif
1512
1513#ifdef CONFIG_COMPAT_32BIT_TIME
1514static int compat_prepare_timeout(const struct old_timespec32 __user *p,
1515 struct timespec64 *ts)
1516{
1517 if (get_old_timespec32(ts, p))
1518 return -EFAULT;
1519 if (!timespec64_valid(ts))
1520 return -EINVAL;
1521 return 0;
1522}
1523
1524SYSCALL_DEFINE5(mq_timedsend_time32, mqd_t, mqdes,
1525 const char __user *, u_msg_ptr,
1526 unsigned int, msg_len, unsigned int, msg_prio,
1527 const struct old_timespec32 __user *, u_abs_timeout)
1528{
1529 struct timespec64 ts, *p = NULL;
1530 if (u_abs_timeout) {
1531 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1532 if (res)
1533 return res;
1534 p = &ts;
1535 }
1536 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1537}
1538
1539SYSCALL_DEFINE5(mq_timedreceive_time32, mqd_t, mqdes,
1540 char __user *, u_msg_ptr,
1541 unsigned int, msg_len, unsigned int __user *, u_msg_prio,
1542 const struct old_timespec32 __user *, u_abs_timeout)
1543{
1544 struct timespec64 ts, *p = NULL;
1545 if (u_abs_timeout) {
1546 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1547 if (res)
1548 return res;
1549 p = &ts;
1550 }
1551 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1552}
1553#endif
1554
1555static const struct inode_operations mqueue_dir_inode_operations = {
1556 .lookup = simple_lookup,
1557 .create = mqueue_create,
1558 .unlink = mqueue_unlink,
1559};
1560
1561static const struct file_operations mqueue_file_operations = {
1562 .flush = mqueue_flush_file,
1563 .poll = mqueue_poll_file,
1564 .read = mqueue_read_file,
1565 .llseek = default_llseek,
1566};
1567
1568static const struct super_operations mqueue_super_ops = {
1569 .alloc_inode = mqueue_alloc_inode,
1570 .free_inode = mqueue_free_inode,
1571 .evict_inode = mqueue_evict_inode,
1572 .statfs = simple_statfs,
1573};
1574
1575static const struct fs_context_operations mqueue_fs_context_ops = {
1576 .free = mqueue_fs_context_free,
1577 .get_tree = mqueue_get_tree,
1578};
1579
1580static struct file_system_type mqueue_fs_type = {
1581 .name = "mqueue",
1582 .init_fs_context = mqueue_init_fs_context,
1583 .kill_sb = kill_litter_super,
1584 .fs_flags = FS_USERNS_MOUNT,
1585};
1586
1587int mq_init_ns(struct ipc_namespace *ns)
1588{
1589 struct vfsmount *m;
1590
1591 ns->mq_queues_count = 0;
1592 ns->mq_queues_max = DFLT_QUEUESMAX;
1593 ns->mq_msg_max = DFLT_MSGMAX;
1594 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1595 ns->mq_msg_default = DFLT_MSG;
1596 ns->mq_msgsize_default = DFLT_MSGSIZE;
1597
1598 m = mq_create_mount(ns);
1599 if (IS_ERR(m))
1600 return PTR_ERR(m);
1601 ns->mq_mnt = m;
1602 return 0;
1603}
1604
1605void mq_clear_sbinfo(struct ipc_namespace *ns)
1606{
1607 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1608}
1609
1610void mq_put_mnt(struct ipc_namespace *ns)
1611{
1612 kern_unmount(ns->mq_mnt);
1613}
1614
1615static int __init init_mqueue_fs(void)
1616{
1617 int error;
1618
1619 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1620 sizeof(struct mqueue_inode_info), 0,
1621 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1622 if (mqueue_inode_cachep == NULL)
1623 return -ENOMEM;
1624
1625 /* ignore failures - they are not fatal */
1626 mq_sysctl_table = mq_register_sysctl_table();
1627
1628 error = register_filesystem(&mqueue_fs_type);
1629 if (error)
1630 goto out_sysctl;
1631
1632 spin_lock_init(&mq_lock);
1633
1634 error = mq_init_ns(&init_ipc_ns);
1635 if (error)
1636 goto out_filesystem;
1637
1638 return 0;
1639
1640out_filesystem:
1641 unregister_filesystem(&mqueue_fs_type);
1642out_sysctl:
1643 if (mq_sysctl_table)
1644 unregister_sysctl_table(mq_sysctl_table);
1645 kmem_cache_destroy(mqueue_inode_cachep);
1646 return error;
1647}
1648
1649device_initcall(init_mqueue_fs);