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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/namei.h>
22#include <linux/sysctl.h>
23#include <linux/poll.h>
24#include <linux/mqueue.h>
25#include <linux/msg.h>
26#include <linux/skbuff.h>
27#include <linux/vmalloc.h>
28#include <linux/netlink.h>
29#include <linux/syscalls.h>
30#include <linux/audit.h>
31#include <linux/signal.h>
32#include <linux/mutex.h>
33#include <linux/nsproxy.h>
34#include <linux/pid.h>
35#include <linux/ipc_namespace.h>
36#include <linux/user_namespace.h>
37#include <linux/slab.h>
38#include <linux/sched/wake_q.h>
39#include <linux/sched/signal.h>
40#include <linux/sched/user.h>
41
42#include <net/sock.h>
43#include "util.h"
44
45#define MQUEUE_MAGIC 0x19800202
46#define DIRENT_SIZE 20
47#define FILENT_SIZE 80
48
49#define SEND 0
50#define RECV 1
51
52#define STATE_NONE 0
53#define STATE_READY 1
54
55struct posix_msg_tree_node {
56 struct rb_node rb_node;
57 struct list_head msg_list;
58 int priority;
59};
60
61struct ext_wait_queue { /* queue of sleeping tasks */
62 struct task_struct *task;
63 struct list_head list;
64 struct msg_msg *msg; /* ptr of loaded message */
65 int state; /* one of STATE_* values */
66};
67
68struct mqueue_inode_info {
69 spinlock_t lock;
70 struct inode vfs_inode;
71 wait_queue_head_t wait_q;
72
73 struct rb_root msg_tree;
74 struct posix_msg_tree_node *node_cache;
75 struct mq_attr attr;
76
77 struct sigevent notify;
78 struct pid *notify_owner;
79 struct user_namespace *notify_user_ns;
80 struct user_struct *user; /* user who created, for accounting */
81 struct sock *notify_sock;
82 struct sk_buff *notify_cookie;
83
84 /* for tasks waiting for free space and messages, respectively */
85 struct ext_wait_queue e_wait_q[2];
86
87 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
88};
89
90static const struct inode_operations mqueue_dir_inode_operations;
91static const struct file_operations mqueue_file_operations;
92static const struct super_operations mqueue_super_ops;
93static void remove_notification(struct mqueue_inode_info *info);
94
95static struct kmem_cache *mqueue_inode_cachep;
96
97static struct ctl_table_header *mq_sysctl_table;
98
99static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
100{
101 return container_of(inode, struct mqueue_inode_info, vfs_inode);
102}
103
104/*
105 * This routine should be called with the mq_lock held.
106 */
107static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
108{
109 return get_ipc_ns(inode->i_sb->s_fs_info);
110}
111
112static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
113{
114 struct ipc_namespace *ns;
115
116 spin_lock(&mq_lock);
117 ns = __get_ns_from_inode(inode);
118 spin_unlock(&mq_lock);
119 return ns;
120}
121
122/* Auxiliary functions to manipulate messages' list */
123static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
124{
125 struct rb_node **p, *parent = NULL;
126 struct posix_msg_tree_node *leaf;
127
128 p = &info->msg_tree.rb_node;
129 while (*p) {
130 parent = *p;
131 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
132
133 if (likely(leaf->priority == msg->m_type))
134 goto insert_msg;
135 else if (msg->m_type < leaf->priority)
136 p = &(*p)->rb_left;
137 else
138 p = &(*p)->rb_right;
139 }
140 if (info->node_cache) {
141 leaf = info->node_cache;
142 info->node_cache = NULL;
143 } else {
144 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
145 if (!leaf)
146 return -ENOMEM;
147 INIT_LIST_HEAD(&leaf->msg_list);
148 }
149 leaf->priority = msg->m_type;
150 rb_link_node(&leaf->rb_node, parent, p);
151 rb_insert_color(&leaf->rb_node, &info->msg_tree);
152insert_msg:
153 info->attr.mq_curmsgs++;
154 info->qsize += msg->m_ts;
155 list_add_tail(&msg->m_list, &leaf->msg_list);
156 return 0;
157}
158
159static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
160{
161 struct rb_node **p, *parent = NULL;
162 struct posix_msg_tree_node *leaf;
163 struct msg_msg *msg;
164
165try_again:
166 p = &info->msg_tree.rb_node;
167 while (*p) {
168 parent = *p;
169 /*
170 * During insert, low priorities go to the left and high to the
171 * right. On receive, we want the highest priorities first, so
172 * walk all the way to the right.
173 */
174 p = &(*p)->rb_right;
175 }
176 if (!parent) {
177 if (info->attr.mq_curmsgs) {
178 pr_warn_once("Inconsistency in POSIX message queue, "
179 "no tree element, but supposedly messages "
180 "should exist!\n");
181 info->attr.mq_curmsgs = 0;
182 }
183 return NULL;
184 }
185 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
186 if (unlikely(list_empty(&leaf->msg_list))) {
187 pr_warn_once("Inconsistency in POSIX message queue, "
188 "empty leaf node but we haven't implemented "
189 "lazy leaf delete!\n");
190 rb_erase(&leaf->rb_node, &info->msg_tree);
191 if (info->node_cache) {
192 kfree(leaf);
193 } else {
194 info->node_cache = leaf;
195 }
196 goto try_again;
197 } else {
198 msg = list_first_entry(&leaf->msg_list,
199 struct msg_msg, m_list);
200 list_del(&msg->m_list);
201 if (list_empty(&leaf->msg_list)) {
202 rb_erase(&leaf->rb_node, &info->msg_tree);
203 if (info->node_cache) {
204 kfree(leaf);
205 } else {
206 info->node_cache = leaf;
207 }
208 }
209 }
210 info->attr.mq_curmsgs--;
211 info->qsize -= msg->m_ts;
212 return msg;
213}
214
215static struct inode *mqueue_get_inode(struct super_block *sb,
216 struct ipc_namespace *ipc_ns, umode_t mode,
217 struct mq_attr *attr)
218{
219 struct user_struct *u = current_user();
220 struct inode *inode;
221 int ret = -ENOMEM;
222
223 inode = new_inode(sb);
224 if (!inode)
225 goto err;
226
227 inode->i_ino = get_next_ino();
228 inode->i_mode = mode;
229 inode->i_uid = current_fsuid();
230 inode->i_gid = current_fsgid();
231 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
232
233 if (S_ISREG(mode)) {
234 struct mqueue_inode_info *info;
235 unsigned long mq_bytes, mq_treesize;
236
237 inode->i_fop = &mqueue_file_operations;
238 inode->i_size = FILENT_SIZE;
239 /* mqueue specific info */
240 info = MQUEUE_I(inode);
241 spin_lock_init(&info->lock);
242 init_waitqueue_head(&info->wait_q);
243 INIT_LIST_HEAD(&info->e_wait_q[0].list);
244 INIT_LIST_HEAD(&info->e_wait_q[1].list);
245 info->notify_owner = NULL;
246 info->notify_user_ns = NULL;
247 info->qsize = 0;
248 info->user = NULL; /* set when all is ok */
249 info->msg_tree = RB_ROOT;
250 info->node_cache = NULL;
251 memset(&info->attr, 0, sizeof(info->attr));
252 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
253 ipc_ns->mq_msg_default);
254 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
255 ipc_ns->mq_msgsize_default);
256 if (attr) {
257 info->attr.mq_maxmsg = attr->mq_maxmsg;
258 info->attr.mq_msgsize = attr->mq_msgsize;
259 }
260 /*
261 * We used to allocate a static array of pointers and account
262 * the size of that array as well as one msg_msg struct per
263 * possible message into the queue size. That's no longer
264 * accurate as the queue is now an rbtree and will grow and
265 * shrink depending on usage patterns. We can, however, still
266 * account one msg_msg struct per message, but the nodes are
267 * allocated depending on priority usage, and most programs
268 * only use one, or a handful, of priorities. However, since
269 * this is pinned memory, we need to assume worst case, so
270 * that means the min(mq_maxmsg, max_priorities) * struct
271 * posix_msg_tree_node.
272 */
273
274 ret = -EINVAL;
275 if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
276 goto out_inode;
277 if (capable(CAP_SYS_RESOURCE)) {
278 if (info->attr.mq_maxmsg > HARD_MSGMAX ||
279 info->attr.mq_msgsize > HARD_MSGSIZEMAX)
280 goto out_inode;
281 } else {
282 if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
283 info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
284 goto out_inode;
285 }
286 ret = -EOVERFLOW;
287 /* check for overflow */
288 if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
289 goto out_inode;
290 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
291 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
292 sizeof(struct posix_msg_tree_node);
293 mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
294 if (mq_bytes + mq_treesize < mq_bytes)
295 goto out_inode;
296 mq_bytes += mq_treesize;
297 spin_lock(&mq_lock);
298 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
299 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
300 spin_unlock(&mq_lock);
301 /* mqueue_evict_inode() releases info->messages */
302 ret = -EMFILE;
303 goto out_inode;
304 }
305 u->mq_bytes += mq_bytes;
306 spin_unlock(&mq_lock);
307
308 /* all is ok */
309 info->user = get_uid(u);
310 } else if (S_ISDIR(mode)) {
311 inc_nlink(inode);
312 /* Some things misbehave if size == 0 on a directory */
313 inode->i_size = 2 * DIRENT_SIZE;
314 inode->i_op = &mqueue_dir_inode_operations;
315 inode->i_fop = &simple_dir_operations;
316 }
317
318 return inode;
319out_inode:
320 iput(inode);
321err:
322 return ERR_PTR(ret);
323}
324
325static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
326{
327 struct inode *inode;
328 struct ipc_namespace *ns = sb->s_fs_info;
329
330 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
331 sb->s_blocksize = PAGE_SIZE;
332 sb->s_blocksize_bits = PAGE_SHIFT;
333 sb->s_magic = MQUEUE_MAGIC;
334 sb->s_op = &mqueue_super_ops;
335
336 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
337 if (IS_ERR(inode))
338 return PTR_ERR(inode);
339
340 sb->s_root = d_make_root(inode);
341 if (!sb->s_root)
342 return -ENOMEM;
343 return 0;
344}
345
346static struct dentry *mqueue_mount(struct file_system_type *fs_type,
347 int flags, const char *dev_name,
348 void *data)
349{
350 struct ipc_namespace *ns;
351 if (flags & SB_KERNMOUNT) {
352 ns = data;
353 data = NULL;
354 } else {
355 ns = current->nsproxy->ipc_ns;
356 }
357 return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super);
358}
359
360static void init_once(void *foo)
361{
362 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
363
364 inode_init_once(&p->vfs_inode);
365}
366
367static struct inode *mqueue_alloc_inode(struct super_block *sb)
368{
369 struct mqueue_inode_info *ei;
370
371 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
372 if (!ei)
373 return NULL;
374 return &ei->vfs_inode;
375}
376
377static void mqueue_i_callback(struct rcu_head *head)
378{
379 struct inode *inode = container_of(head, struct inode, i_rcu);
380 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
381}
382
383static void mqueue_destroy_inode(struct inode *inode)
384{
385 call_rcu(&inode->i_rcu, mqueue_i_callback);
386}
387
388static void mqueue_evict_inode(struct inode *inode)
389{
390 struct mqueue_inode_info *info;
391 struct user_struct *user;
392 unsigned long mq_bytes, mq_treesize;
393 struct ipc_namespace *ipc_ns;
394 struct msg_msg *msg;
395
396 clear_inode(inode);
397
398 if (S_ISDIR(inode->i_mode))
399 return;
400
401 ipc_ns = get_ns_from_inode(inode);
402 info = MQUEUE_I(inode);
403 spin_lock(&info->lock);
404 while ((msg = msg_get(info)) != NULL)
405 free_msg(msg);
406 kfree(info->node_cache);
407 spin_unlock(&info->lock);
408
409 /* Total amount of bytes accounted for the mqueue */
410 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
411 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
412 sizeof(struct posix_msg_tree_node);
413
414 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
415 info->attr.mq_msgsize);
416
417 user = info->user;
418 if (user) {
419 spin_lock(&mq_lock);
420 user->mq_bytes -= mq_bytes;
421 /*
422 * get_ns_from_inode() ensures that the
423 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
424 * to which we now hold a reference, or it is NULL.
425 * We can't put it here under mq_lock, though.
426 */
427 if (ipc_ns)
428 ipc_ns->mq_queues_count--;
429 spin_unlock(&mq_lock);
430 free_uid(user);
431 }
432 if (ipc_ns)
433 put_ipc_ns(ipc_ns);
434}
435
436static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
437{
438 struct inode *dir = dentry->d_parent->d_inode;
439 struct inode *inode;
440 struct mq_attr *attr = arg;
441 int error;
442 struct ipc_namespace *ipc_ns;
443
444 spin_lock(&mq_lock);
445 ipc_ns = __get_ns_from_inode(dir);
446 if (!ipc_ns) {
447 error = -EACCES;
448 goto out_unlock;
449 }
450
451 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
452 !capable(CAP_SYS_RESOURCE)) {
453 error = -ENOSPC;
454 goto out_unlock;
455 }
456 ipc_ns->mq_queues_count++;
457 spin_unlock(&mq_lock);
458
459 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
460 if (IS_ERR(inode)) {
461 error = PTR_ERR(inode);
462 spin_lock(&mq_lock);
463 ipc_ns->mq_queues_count--;
464 goto out_unlock;
465 }
466
467 put_ipc_ns(ipc_ns);
468 dir->i_size += DIRENT_SIZE;
469 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
470
471 d_instantiate(dentry, inode);
472 dget(dentry);
473 return 0;
474out_unlock:
475 spin_unlock(&mq_lock);
476 if (ipc_ns)
477 put_ipc_ns(ipc_ns);
478 return error;
479}
480
481static int mqueue_create(struct inode *dir, struct dentry *dentry,
482 umode_t mode, bool excl)
483{
484 return mqueue_create_attr(dentry, mode, NULL);
485}
486
487static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
488{
489 struct inode *inode = d_inode(dentry);
490
491 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
492 dir->i_size -= DIRENT_SIZE;
493 drop_nlink(inode);
494 dput(dentry);
495 return 0;
496}
497
498/*
499* This is routine for system read from queue file.
500* To avoid mess with doing here some sort of mq_receive we allow
501* to read only queue size & notification info (the only values
502* that are interesting from user point of view and aren't accessible
503* through std routines)
504*/
505static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
506 size_t count, loff_t *off)
507{
508 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
509 char buffer[FILENT_SIZE];
510 ssize_t ret;
511
512 spin_lock(&info->lock);
513 snprintf(buffer, sizeof(buffer),
514 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
515 info->qsize,
516 info->notify_owner ? info->notify.sigev_notify : 0,
517 (info->notify_owner &&
518 info->notify.sigev_notify == SIGEV_SIGNAL) ?
519 info->notify.sigev_signo : 0,
520 pid_vnr(info->notify_owner));
521 spin_unlock(&info->lock);
522 buffer[sizeof(buffer)-1] = '\0';
523
524 ret = simple_read_from_buffer(u_data, count, off, buffer,
525 strlen(buffer));
526 if (ret <= 0)
527 return ret;
528
529 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
530 return ret;
531}
532
533static int mqueue_flush_file(struct file *filp, fl_owner_t id)
534{
535 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
536
537 spin_lock(&info->lock);
538 if (task_tgid(current) == info->notify_owner)
539 remove_notification(info);
540
541 spin_unlock(&info->lock);
542 return 0;
543}
544
545static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
546{
547 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
548 __poll_t retval = 0;
549
550 poll_wait(filp, &info->wait_q, poll_tab);
551
552 spin_lock(&info->lock);
553 if (info->attr.mq_curmsgs)
554 retval = EPOLLIN | EPOLLRDNORM;
555
556 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
557 retval |= EPOLLOUT | EPOLLWRNORM;
558 spin_unlock(&info->lock);
559
560 return retval;
561}
562
563/* Adds current to info->e_wait_q[sr] before element with smaller prio */
564static void wq_add(struct mqueue_inode_info *info, int sr,
565 struct ext_wait_queue *ewp)
566{
567 struct ext_wait_queue *walk;
568
569 ewp->task = current;
570
571 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
572 if (walk->task->prio <= current->prio) {
573 list_add_tail(&ewp->list, &walk->list);
574 return;
575 }
576 }
577 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
578}
579
580/*
581 * Puts current task to sleep. Caller must hold queue lock. After return
582 * lock isn't held.
583 * sr: SEND or RECV
584 */
585static int wq_sleep(struct mqueue_inode_info *info, int sr,
586 ktime_t *timeout, struct ext_wait_queue *ewp)
587 __releases(&info->lock)
588{
589 int retval;
590 signed long time;
591
592 wq_add(info, sr, ewp);
593
594 for (;;) {
595 __set_current_state(TASK_INTERRUPTIBLE);
596
597 spin_unlock(&info->lock);
598 time = schedule_hrtimeout_range_clock(timeout, 0,
599 HRTIMER_MODE_ABS, CLOCK_REALTIME);
600
601 if (ewp->state == STATE_READY) {
602 retval = 0;
603 goto out;
604 }
605 spin_lock(&info->lock);
606 if (ewp->state == STATE_READY) {
607 retval = 0;
608 goto out_unlock;
609 }
610 if (signal_pending(current)) {
611 retval = -ERESTARTSYS;
612 break;
613 }
614 if (time == 0) {
615 retval = -ETIMEDOUT;
616 break;
617 }
618 }
619 list_del(&ewp->list);
620out_unlock:
621 spin_unlock(&info->lock);
622out:
623 return retval;
624}
625
626/*
627 * Returns waiting task that should be serviced first or NULL if none exists
628 */
629static struct ext_wait_queue *wq_get_first_waiter(
630 struct mqueue_inode_info *info, int sr)
631{
632 struct list_head *ptr;
633
634 ptr = info->e_wait_q[sr].list.prev;
635 if (ptr == &info->e_wait_q[sr].list)
636 return NULL;
637 return list_entry(ptr, struct ext_wait_queue, list);
638}
639
640
641static inline void set_cookie(struct sk_buff *skb, char code)
642{
643 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
644}
645
646/*
647 * The next function is only to split too long sys_mq_timedsend
648 */
649static void __do_notify(struct mqueue_inode_info *info)
650{
651 /* notification
652 * invoked when there is registered process and there isn't process
653 * waiting synchronously for message AND state of queue changed from
654 * empty to not empty. Here we are sure that no one is waiting
655 * synchronously. */
656 if (info->notify_owner &&
657 info->attr.mq_curmsgs == 1) {
658 struct siginfo sig_i;
659 switch (info->notify.sigev_notify) {
660 case SIGEV_NONE:
661 break;
662 case SIGEV_SIGNAL:
663 /* sends signal */
664
665 clear_siginfo(&sig_i);
666 sig_i.si_signo = info->notify.sigev_signo;
667 sig_i.si_errno = 0;
668 sig_i.si_code = SI_MESGQ;
669 sig_i.si_value = info->notify.sigev_value;
670 /* map current pid/uid into info->owner's namespaces */
671 rcu_read_lock();
672 sig_i.si_pid = task_tgid_nr_ns(current,
673 ns_of_pid(info->notify_owner));
674 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
675 rcu_read_unlock();
676
677 kill_pid_info(info->notify.sigev_signo,
678 &sig_i, info->notify_owner);
679 break;
680 case SIGEV_THREAD:
681 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
682 netlink_sendskb(info->notify_sock, info->notify_cookie);
683 break;
684 }
685 /* after notification unregisters process */
686 put_pid(info->notify_owner);
687 put_user_ns(info->notify_user_ns);
688 info->notify_owner = NULL;
689 info->notify_user_ns = NULL;
690 }
691 wake_up(&info->wait_q);
692}
693
694static int prepare_timeout(const struct timespec __user *u_abs_timeout,
695 struct timespec64 *ts)
696{
697 if (get_timespec64(ts, u_abs_timeout))
698 return -EFAULT;
699 if (!timespec64_valid(ts))
700 return -EINVAL;
701 return 0;
702}
703
704static void remove_notification(struct mqueue_inode_info *info)
705{
706 if (info->notify_owner != NULL &&
707 info->notify.sigev_notify == SIGEV_THREAD) {
708 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
709 netlink_sendskb(info->notify_sock, info->notify_cookie);
710 }
711 put_pid(info->notify_owner);
712 put_user_ns(info->notify_user_ns);
713 info->notify_owner = NULL;
714 info->notify_user_ns = NULL;
715}
716
717static int prepare_open(struct dentry *dentry, int oflag, int ro,
718 umode_t mode, struct filename *name,
719 struct mq_attr *attr)
720{
721 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
722 MAY_READ | MAY_WRITE };
723 int acc;
724
725 if (d_really_is_negative(dentry)) {
726 if (!(oflag & O_CREAT))
727 return -ENOENT;
728 if (ro)
729 return ro;
730 audit_inode_parent_hidden(name, dentry->d_parent);
731 return vfs_mkobj(dentry, mode & ~current_umask(),
732 mqueue_create_attr, attr);
733 }
734 /* it already existed */
735 audit_inode(name, dentry, 0);
736 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
737 return -EEXIST;
738 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
739 return -EINVAL;
740 acc = oflag2acc[oflag & O_ACCMODE];
741 return inode_permission(d_inode(dentry), acc);
742}
743
744static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
745 struct mq_attr *attr)
746{
747 struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
748 struct dentry *root = mnt->mnt_root;
749 struct filename *name;
750 struct path path;
751 int fd, error;
752 int ro;
753
754 audit_mq_open(oflag, mode, attr);
755
756 if (IS_ERR(name = getname(u_name)))
757 return PTR_ERR(name);
758
759 fd = get_unused_fd_flags(O_CLOEXEC);
760 if (fd < 0)
761 goto out_putname;
762
763 ro = mnt_want_write(mnt); /* we'll drop it in any case */
764 inode_lock(d_inode(root));
765 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
766 if (IS_ERR(path.dentry)) {
767 error = PTR_ERR(path.dentry);
768 goto out_putfd;
769 }
770 path.mnt = mntget(mnt);
771 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
772 if (!error) {
773 struct file *file = dentry_open(&path, oflag, current_cred());
774 if (!IS_ERR(file))
775 fd_install(fd, file);
776 else
777 error = PTR_ERR(file);
778 }
779 path_put(&path);
780out_putfd:
781 if (error) {
782 put_unused_fd(fd);
783 fd = error;
784 }
785 inode_unlock(d_inode(root));
786 if (!ro)
787 mnt_drop_write(mnt);
788out_putname:
789 putname(name);
790 return fd;
791}
792
793SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
794 struct mq_attr __user *, u_attr)
795{
796 struct mq_attr attr;
797 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
798 return -EFAULT;
799
800 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
801}
802
803SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
804{
805 int err;
806 struct filename *name;
807 struct dentry *dentry;
808 struct inode *inode = NULL;
809 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
810 struct vfsmount *mnt = ipc_ns->mq_mnt;
811
812 name = getname(u_name);
813 if (IS_ERR(name))
814 return PTR_ERR(name);
815
816 audit_inode_parent_hidden(name, mnt->mnt_root);
817 err = mnt_want_write(mnt);
818 if (err)
819 goto out_name;
820 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
821 dentry = lookup_one_len(name->name, mnt->mnt_root,
822 strlen(name->name));
823 if (IS_ERR(dentry)) {
824 err = PTR_ERR(dentry);
825 goto out_unlock;
826 }
827
828 inode = d_inode(dentry);
829 if (!inode) {
830 err = -ENOENT;
831 } else {
832 ihold(inode);
833 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
834 }
835 dput(dentry);
836
837out_unlock:
838 inode_unlock(d_inode(mnt->mnt_root));
839 if (inode)
840 iput(inode);
841 mnt_drop_write(mnt);
842out_name:
843 putname(name);
844
845 return err;
846}
847
848/* Pipelined send and receive functions.
849 *
850 * If a receiver finds no waiting message, then it registers itself in the
851 * list of waiting receivers. A sender checks that list before adding the new
852 * message into the message array. If there is a waiting receiver, then it
853 * bypasses the message array and directly hands the message over to the
854 * receiver. The receiver accepts the message and returns without grabbing the
855 * queue spinlock:
856 *
857 * - Set pointer to message.
858 * - Queue the receiver task for later wakeup (without the info->lock).
859 * - Update its state to STATE_READY. Now the receiver can continue.
860 * - Wake up the process after the lock is dropped. Should the process wake up
861 * before this wakeup (due to a timeout or a signal) it will either see
862 * STATE_READY and continue or acquire the lock to check the state again.
863 *
864 * The same algorithm is used for senders.
865 */
866
867/* pipelined_send() - send a message directly to the task waiting in
868 * sys_mq_timedreceive() (without inserting message into a queue).
869 */
870static inline void pipelined_send(struct wake_q_head *wake_q,
871 struct mqueue_inode_info *info,
872 struct msg_msg *message,
873 struct ext_wait_queue *receiver)
874{
875 receiver->msg = message;
876 list_del(&receiver->list);
877 wake_q_add(wake_q, receiver->task);
878 /*
879 * Rely on the implicit cmpxchg barrier from wake_q_add such
880 * that we can ensure that updating receiver->state is the last
881 * write operation: As once set, the receiver can continue,
882 * and if we don't have the reference count from the wake_q,
883 * yet, at that point we can later have a use-after-free
884 * condition and bogus wakeup.
885 */
886 receiver->state = STATE_READY;
887}
888
889/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
890 * gets its message and put to the queue (we have one free place for sure). */
891static inline void pipelined_receive(struct wake_q_head *wake_q,
892 struct mqueue_inode_info *info)
893{
894 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
895
896 if (!sender) {
897 /* for poll */
898 wake_up_interruptible(&info->wait_q);
899 return;
900 }
901 if (msg_insert(sender->msg, info))
902 return;
903
904 list_del(&sender->list);
905 wake_q_add(wake_q, sender->task);
906 sender->state = STATE_READY;
907}
908
909static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
910 size_t msg_len, unsigned int msg_prio,
911 struct timespec64 *ts)
912{
913 struct fd f;
914 struct inode *inode;
915 struct ext_wait_queue wait;
916 struct ext_wait_queue *receiver;
917 struct msg_msg *msg_ptr;
918 struct mqueue_inode_info *info;
919 ktime_t expires, *timeout = NULL;
920 struct posix_msg_tree_node *new_leaf = NULL;
921 int ret = 0;
922 DEFINE_WAKE_Q(wake_q);
923
924 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
925 return -EINVAL;
926
927 if (ts) {
928 expires = timespec64_to_ktime(*ts);
929 timeout = &expires;
930 }
931
932 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
933
934 f = fdget(mqdes);
935 if (unlikely(!f.file)) {
936 ret = -EBADF;
937 goto out;
938 }
939
940 inode = file_inode(f.file);
941 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
942 ret = -EBADF;
943 goto out_fput;
944 }
945 info = MQUEUE_I(inode);
946 audit_file(f.file);
947
948 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
949 ret = -EBADF;
950 goto out_fput;
951 }
952
953 if (unlikely(msg_len > info->attr.mq_msgsize)) {
954 ret = -EMSGSIZE;
955 goto out_fput;
956 }
957
958 /* First try to allocate memory, before doing anything with
959 * existing queues. */
960 msg_ptr = load_msg(u_msg_ptr, msg_len);
961 if (IS_ERR(msg_ptr)) {
962 ret = PTR_ERR(msg_ptr);
963 goto out_fput;
964 }
965 msg_ptr->m_ts = msg_len;
966 msg_ptr->m_type = msg_prio;
967
968 /*
969 * msg_insert really wants us to have a valid, spare node struct so
970 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
971 * fall back to that if necessary.
972 */
973 if (!info->node_cache)
974 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
975
976 spin_lock(&info->lock);
977
978 if (!info->node_cache && new_leaf) {
979 /* Save our speculative allocation into the cache */
980 INIT_LIST_HEAD(&new_leaf->msg_list);
981 info->node_cache = new_leaf;
982 new_leaf = NULL;
983 } else {
984 kfree(new_leaf);
985 }
986
987 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
988 if (f.file->f_flags & O_NONBLOCK) {
989 ret = -EAGAIN;
990 } else {
991 wait.task = current;
992 wait.msg = (void *) msg_ptr;
993 wait.state = STATE_NONE;
994 ret = wq_sleep(info, SEND, timeout, &wait);
995 /*
996 * wq_sleep must be called with info->lock held, and
997 * returns with the lock released
998 */
999 goto out_free;
1000 }
1001 } else {
1002 receiver = wq_get_first_waiter(info, RECV);
1003 if (receiver) {
1004 pipelined_send(&wake_q, info, msg_ptr, receiver);
1005 } else {
1006 /* adds message to the queue */
1007 ret = msg_insert(msg_ptr, info);
1008 if (ret)
1009 goto out_unlock;
1010 __do_notify(info);
1011 }
1012 inode->i_atime = inode->i_mtime = inode->i_ctime =
1013 current_time(inode);
1014 }
1015out_unlock:
1016 spin_unlock(&info->lock);
1017 wake_up_q(&wake_q);
1018out_free:
1019 if (ret)
1020 free_msg(msg_ptr);
1021out_fput:
1022 fdput(f);
1023out:
1024 return ret;
1025}
1026
1027static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1028 size_t msg_len, unsigned int __user *u_msg_prio,
1029 struct timespec64 *ts)
1030{
1031 ssize_t ret;
1032 struct msg_msg *msg_ptr;
1033 struct fd f;
1034 struct inode *inode;
1035 struct mqueue_inode_info *info;
1036 struct ext_wait_queue wait;
1037 ktime_t expires, *timeout = NULL;
1038 struct posix_msg_tree_node *new_leaf = NULL;
1039
1040 if (ts) {
1041 expires = timespec64_to_ktime(*ts);
1042 timeout = &expires;
1043 }
1044
1045 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1046
1047 f = fdget(mqdes);
1048 if (unlikely(!f.file)) {
1049 ret = -EBADF;
1050 goto out;
1051 }
1052
1053 inode = file_inode(f.file);
1054 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1055 ret = -EBADF;
1056 goto out_fput;
1057 }
1058 info = MQUEUE_I(inode);
1059 audit_file(f.file);
1060
1061 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1062 ret = -EBADF;
1063 goto out_fput;
1064 }
1065
1066 /* checks if buffer is big enough */
1067 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1068 ret = -EMSGSIZE;
1069 goto out_fput;
1070 }
1071
1072 /*
1073 * msg_insert really wants us to have a valid, spare node struct so
1074 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1075 * fall back to that if necessary.
1076 */
1077 if (!info->node_cache)
1078 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1079
1080 spin_lock(&info->lock);
1081
1082 if (!info->node_cache && new_leaf) {
1083 /* Save our speculative allocation into the cache */
1084 INIT_LIST_HEAD(&new_leaf->msg_list);
1085 info->node_cache = new_leaf;
1086 } else {
1087 kfree(new_leaf);
1088 }
1089
1090 if (info->attr.mq_curmsgs == 0) {
1091 if (f.file->f_flags & O_NONBLOCK) {
1092 spin_unlock(&info->lock);
1093 ret = -EAGAIN;
1094 } else {
1095 wait.task = current;
1096 wait.state = STATE_NONE;
1097 ret = wq_sleep(info, RECV, timeout, &wait);
1098 msg_ptr = wait.msg;
1099 }
1100 } else {
1101 DEFINE_WAKE_Q(wake_q);
1102
1103 msg_ptr = msg_get(info);
1104
1105 inode->i_atime = inode->i_mtime = inode->i_ctime =
1106 current_time(inode);
1107
1108 /* There is now free space in queue. */
1109 pipelined_receive(&wake_q, info);
1110 spin_unlock(&info->lock);
1111 wake_up_q(&wake_q);
1112 ret = 0;
1113 }
1114 if (ret == 0) {
1115 ret = msg_ptr->m_ts;
1116
1117 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1118 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1119 ret = -EFAULT;
1120 }
1121 free_msg(msg_ptr);
1122 }
1123out_fput:
1124 fdput(f);
1125out:
1126 return ret;
1127}
1128
1129SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1130 size_t, msg_len, unsigned int, msg_prio,
1131 const struct timespec __user *, u_abs_timeout)
1132{
1133 struct timespec64 ts, *p = NULL;
1134 if (u_abs_timeout) {
1135 int res = prepare_timeout(u_abs_timeout, &ts);
1136 if (res)
1137 return res;
1138 p = &ts;
1139 }
1140 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1141}
1142
1143SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1144 size_t, msg_len, unsigned int __user *, u_msg_prio,
1145 const struct timespec __user *, u_abs_timeout)
1146{
1147 struct timespec64 ts, *p = NULL;
1148 if (u_abs_timeout) {
1149 int res = prepare_timeout(u_abs_timeout, &ts);
1150 if (res)
1151 return res;
1152 p = &ts;
1153 }
1154 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1155}
1156
1157/*
1158 * Notes: the case when user wants us to deregister (with NULL as pointer)
1159 * and he isn't currently owner of notification, will be silently discarded.
1160 * It isn't explicitly defined in the POSIX.
1161 */
1162static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1163{
1164 int ret;
1165 struct fd f;
1166 struct sock *sock;
1167 struct inode *inode;
1168 struct mqueue_inode_info *info;
1169 struct sk_buff *nc;
1170
1171 audit_mq_notify(mqdes, notification);
1172
1173 nc = NULL;
1174 sock = NULL;
1175 if (notification != NULL) {
1176 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1177 notification->sigev_notify != SIGEV_SIGNAL &&
1178 notification->sigev_notify != SIGEV_THREAD))
1179 return -EINVAL;
1180 if (notification->sigev_notify == SIGEV_SIGNAL &&
1181 !valid_signal(notification->sigev_signo)) {
1182 return -EINVAL;
1183 }
1184 if (notification->sigev_notify == SIGEV_THREAD) {
1185 long timeo;
1186
1187 /* create the notify skb */
1188 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1189 if (!nc) {
1190 ret = -ENOMEM;
1191 goto out;
1192 }
1193 if (copy_from_user(nc->data,
1194 notification->sigev_value.sival_ptr,
1195 NOTIFY_COOKIE_LEN)) {
1196 ret = -EFAULT;
1197 goto out;
1198 }
1199
1200 /* TODO: add a header? */
1201 skb_put(nc, NOTIFY_COOKIE_LEN);
1202 /* and attach it to the socket */
1203retry:
1204 f = fdget(notification->sigev_signo);
1205 if (!f.file) {
1206 ret = -EBADF;
1207 goto out;
1208 }
1209 sock = netlink_getsockbyfilp(f.file);
1210 fdput(f);
1211 if (IS_ERR(sock)) {
1212 ret = PTR_ERR(sock);
1213 sock = NULL;
1214 goto out;
1215 }
1216
1217 timeo = MAX_SCHEDULE_TIMEOUT;
1218 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1219 if (ret == 1) {
1220 sock = NULL;
1221 goto retry;
1222 }
1223 if (ret) {
1224 sock = NULL;
1225 nc = NULL;
1226 goto out;
1227 }
1228 }
1229 }
1230
1231 f = fdget(mqdes);
1232 if (!f.file) {
1233 ret = -EBADF;
1234 goto out;
1235 }
1236
1237 inode = file_inode(f.file);
1238 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1239 ret = -EBADF;
1240 goto out_fput;
1241 }
1242 info = MQUEUE_I(inode);
1243
1244 ret = 0;
1245 spin_lock(&info->lock);
1246 if (notification == NULL) {
1247 if (info->notify_owner == task_tgid(current)) {
1248 remove_notification(info);
1249 inode->i_atime = inode->i_ctime = current_time(inode);
1250 }
1251 } else if (info->notify_owner != NULL) {
1252 ret = -EBUSY;
1253 } else {
1254 switch (notification->sigev_notify) {
1255 case SIGEV_NONE:
1256 info->notify.sigev_notify = SIGEV_NONE;
1257 break;
1258 case SIGEV_THREAD:
1259 info->notify_sock = sock;
1260 info->notify_cookie = nc;
1261 sock = NULL;
1262 nc = NULL;
1263 info->notify.sigev_notify = SIGEV_THREAD;
1264 break;
1265 case SIGEV_SIGNAL:
1266 info->notify.sigev_signo = notification->sigev_signo;
1267 info->notify.sigev_value = notification->sigev_value;
1268 info->notify.sigev_notify = SIGEV_SIGNAL;
1269 break;
1270 }
1271
1272 info->notify_owner = get_pid(task_tgid(current));
1273 info->notify_user_ns = get_user_ns(current_user_ns());
1274 inode->i_atime = inode->i_ctime = current_time(inode);
1275 }
1276 spin_unlock(&info->lock);
1277out_fput:
1278 fdput(f);
1279out:
1280 if (sock)
1281 netlink_detachskb(sock, nc);
1282 else if (nc)
1283 dev_kfree_skb(nc);
1284
1285 return ret;
1286}
1287
1288SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1289 const struct sigevent __user *, u_notification)
1290{
1291 struct sigevent n, *p = NULL;
1292 if (u_notification) {
1293 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1294 return -EFAULT;
1295 p = &n;
1296 }
1297 return do_mq_notify(mqdes, p);
1298}
1299
1300static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1301{
1302 struct fd f;
1303 struct inode *inode;
1304 struct mqueue_inode_info *info;
1305
1306 if (new && (new->mq_flags & (~O_NONBLOCK)))
1307 return -EINVAL;
1308
1309 f = fdget(mqdes);
1310 if (!f.file)
1311 return -EBADF;
1312
1313 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1314 fdput(f);
1315 return -EBADF;
1316 }
1317
1318 inode = file_inode(f.file);
1319 info = MQUEUE_I(inode);
1320
1321 spin_lock(&info->lock);
1322
1323 if (old) {
1324 *old = info->attr;
1325 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1326 }
1327 if (new) {
1328 audit_mq_getsetattr(mqdes, new);
1329 spin_lock(&f.file->f_lock);
1330 if (new->mq_flags & O_NONBLOCK)
1331 f.file->f_flags |= O_NONBLOCK;
1332 else
1333 f.file->f_flags &= ~O_NONBLOCK;
1334 spin_unlock(&f.file->f_lock);
1335
1336 inode->i_atime = inode->i_ctime = current_time(inode);
1337 }
1338
1339 spin_unlock(&info->lock);
1340 fdput(f);
1341 return 0;
1342}
1343
1344SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1345 const struct mq_attr __user *, u_mqstat,
1346 struct mq_attr __user *, u_omqstat)
1347{
1348 int ret;
1349 struct mq_attr mqstat, omqstat;
1350 struct mq_attr *new = NULL, *old = NULL;
1351
1352 if (u_mqstat) {
1353 new = &mqstat;
1354 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1355 return -EFAULT;
1356 }
1357 if (u_omqstat)
1358 old = &omqstat;
1359
1360 ret = do_mq_getsetattr(mqdes, new, old);
1361 if (ret || !old)
1362 return ret;
1363
1364 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1365 return -EFAULT;
1366 return 0;
1367}
1368
1369#ifdef CONFIG_COMPAT
1370
1371struct compat_mq_attr {
1372 compat_long_t mq_flags; /* message queue flags */
1373 compat_long_t mq_maxmsg; /* maximum number of messages */
1374 compat_long_t mq_msgsize; /* maximum message size */
1375 compat_long_t mq_curmsgs; /* number of messages currently queued */
1376 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1377};
1378
1379static inline int get_compat_mq_attr(struct mq_attr *attr,
1380 const struct compat_mq_attr __user *uattr)
1381{
1382 struct compat_mq_attr v;
1383
1384 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1385 return -EFAULT;
1386
1387 memset(attr, 0, sizeof(*attr));
1388 attr->mq_flags = v.mq_flags;
1389 attr->mq_maxmsg = v.mq_maxmsg;
1390 attr->mq_msgsize = v.mq_msgsize;
1391 attr->mq_curmsgs = v.mq_curmsgs;
1392 return 0;
1393}
1394
1395static inline int put_compat_mq_attr(const struct mq_attr *attr,
1396 struct compat_mq_attr __user *uattr)
1397{
1398 struct compat_mq_attr v;
1399
1400 memset(&v, 0, sizeof(v));
1401 v.mq_flags = attr->mq_flags;
1402 v.mq_maxmsg = attr->mq_maxmsg;
1403 v.mq_msgsize = attr->mq_msgsize;
1404 v.mq_curmsgs = attr->mq_curmsgs;
1405 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1406 return -EFAULT;
1407 return 0;
1408}
1409
1410COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1411 int, oflag, compat_mode_t, mode,
1412 struct compat_mq_attr __user *, u_attr)
1413{
1414 struct mq_attr attr, *p = NULL;
1415 if (u_attr && oflag & O_CREAT) {
1416 p = &attr;
1417 if (get_compat_mq_attr(&attr, u_attr))
1418 return -EFAULT;
1419 }
1420 return do_mq_open(u_name, oflag, mode, p);
1421}
1422
1423static int compat_prepare_timeout(const struct compat_timespec __user *p,
1424 struct timespec64 *ts)
1425{
1426 if (compat_get_timespec64(ts, p))
1427 return -EFAULT;
1428 if (!timespec64_valid(ts))
1429 return -EINVAL;
1430 return 0;
1431}
1432
1433COMPAT_SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes,
1434 const char __user *, u_msg_ptr,
1435 compat_size_t, msg_len, unsigned int, msg_prio,
1436 const struct compat_timespec __user *, u_abs_timeout)
1437{
1438 struct timespec64 ts, *p = NULL;
1439 if (u_abs_timeout) {
1440 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1441 if (res)
1442 return res;
1443 p = &ts;
1444 }
1445 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1446}
1447
1448COMPAT_SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes,
1449 char __user *, u_msg_ptr,
1450 compat_size_t, msg_len, unsigned int __user *, u_msg_prio,
1451 const struct compat_timespec __user *, u_abs_timeout)
1452{
1453 struct timespec64 ts, *p = NULL;
1454 if (u_abs_timeout) {
1455 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1456 if (res)
1457 return res;
1458 p = &ts;
1459 }
1460 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1461}
1462
1463COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1464 const struct compat_sigevent __user *, u_notification)
1465{
1466 struct sigevent n, *p = NULL;
1467 if (u_notification) {
1468 if (get_compat_sigevent(&n, u_notification))
1469 return -EFAULT;
1470 if (n.sigev_notify == SIGEV_THREAD)
1471 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1472 p = &n;
1473 }
1474 return do_mq_notify(mqdes, p);
1475}
1476
1477COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1478 const struct compat_mq_attr __user *, u_mqstat,
1479 struct compat_mq_attr __user *, u_omqstat)
1480{
1481 int ret;
1482 struct mq_attr mqstat, omqstat;
1483 struct mq_attr *new = NULL, *old = NULL;
1484
1485 if (u_mqstat) {
1486 new = &mqstat;
1487 if (get_compat_mq_attr(new, u_mqstat))
1488 return -EFAULT;
1489 }
1490 if (u_omqstat)
1491 old = &omqstat;
1492
1493 ret = do_mq_getsetattr(mqdes, new, old);
1494 if (ret || !old)
1495 return ret;
1496
1497 if (put_compat_mq_attr(old, u_omqstat))
1498 return -EFAULT;
1499 return 0;
1500}
1501#endif
1502
1503static const struct inode_operations mqueue_dir_inode_operations = {
1504 .lookup = simple_lookup,
1505 .create = mqueue_create,
1506 .unlink = mqueue_unlink,
1507};
1508
1509static const struct file_operations mqueue_file_operations = {
1510 .flush = mqueue_flush_file,
1511 .poll = mqueue_poll_file,
1512 .read = mqueue_read_file,
1513 .llseek = default_llseek,
1514};
1515
1516static const struct super_operations mqueue_super_ops = {
1517 .alloc_inode = mqueue_alloc_inode,
1518 .destroy_inode = mqueue_destroy_inode,
1519 .evict_inode = mqueue_evict_inode,
1520 .statfs = simple_statfs,
1521};
1522
1523static struct file_system_type mqueue_fs_type = {
1524 .name = "mqueue",
1525 .mount = mqueue_mount,
1526 .kill_sb = kill_litter_super,
1527 .fs_flags = FS_USERNS_MOUNT,
1528};
1529
1530int mq_init_ns(struct ipc_namespace *ns)
1531{
1532 ns->mq_queues_count = 0;
1533 ns->mq_queues_max = DFLT_QUEUESMAX;
1534 ns->mq_msg_max = DFLT_MSGMAX;
1535 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1536 ns->mq_msg_default = DFLT_MSG;
1537 ns->mq_msgsize_default = DFLT_MSGSIZE;
1538
1539 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1540 if (IS_ERR(ns->mq_mnt)) {
1541 int err = PTR_ERR(ns->mq_mnt);
1542 ns->mq_mnt = NULL;
1543 return err;
1544 }
1545 return 0;
1546}
1547
1548void mq_clear_sbinfo(struct ipc_namespace *ns)
1549{
1550 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1551}
1552
1553void mq_put_mnt(struct ipc_namespace *ns)
1554{
1555 kern_unmount(ns->mq_mnt);
1556}
1557
1558static int __init init_mqueue_fs(void)
1559{
1560 int error;
1561
1562 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1563 sizeof(struct mqueue_inode_info), 0,
1564 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1565 if (mqueue_inode_cachep == NULL)
1566 return -ENOMEM;
1567
1568 /* ignore failures - they are not fatal */
1569 mq_sysctl_table = mq_register_sysctl_table();
1570
1571 error = register_filesystem(&mqueue_fs_type);
1572 if (error)
1573 goto out_sysctl;
1574
1575 spin_lock_init(&mq_lock);
1576
1577 error = mq_init_ns(&init_ipc_ns);
1578 if (error)
1579 goto out_filesystem;
1580
1581 return 0;
1582
1583out_filesystem:
1584 unregister_filesystem(&mqueue_fs_type);
1585out_sysctl:
1586 if (mq_sysctl_table)
1587 unregister_sysctl_table(mq_sysctl_table);
1588 kmem_cache_destroy(mqueue_inode_cachep);
1589 return error;
1590}
1591
1592device_initcall(init_mqueue_fs);
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 user_struct *user; /* 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 user_struct *u = current_user();
296 struct inode *inode;
297 int ret = -ENOMEM;
298
299 inode = new_inode(sb);
300 if (!inode)
301 goto err;
302
303 inode->i_ino = get_next_ino();
304 inode->i_mode = mode;
305 inode->i_uid = current_fsuid();
306 inode->i_gid = current_fsgid();
307 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
308
309 if (S_ISREG(mode)) {
310 struct mqueue_inode_info *info;
311 unsigned long mq_bytes, mq_treesize;
312
313 inode->i_fop = &mqueue_file_operations;
314 inode->i_size = FILENT_SIZE;
315 /* mqueue specific info */
316 info = MQUEUE_I(inode);
317 spin_lock_init(&info->lock);
318 init_waitqueue_head(&info->wait_q);
319 INIT_LIST_HEAD(&info->e_wait_q[0].list);
320 INIT_LIST_HEAD(&info->e_wait_q[1].list);
321 info->notify_owner = NULL;
322 info->notify_user_ns = NULL;
323 info->qsize = 0;
324 info->user = NULL; /* set when all is ok */
325 info->msg_tree = RB_ROOT;
326 info->msg_tree_rightmost = NULL;
327 info->node_cache = NULL;
328 memset(&info->attr, 0, sizeof(info->attr));
329 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
330 ipc_ns->mq_msg_default);
331 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
332 ipc_ns->mq_msgsize_default);
333 if (attr) {
334 info->attr.mq_maxmsg = attr->mq_maxmsg;
335 info->attr.mq_msgsize = attr->mq_msgsize;
336 }
337 /*
338 * We used to allocate a static array of pointers and account
339 * the size of that array as well as one msg_msg struct per
340 * possible message into the queue size. That's no longer
341 * accurate as the queue is now an rbtree and will grow and
342 * shrink depending on usage patterns. We can, however, still
343 * account one msg_msg struct per message, but the nodes are
344 * allocated depending on priority usage, and most programs
345 * only use one, or a handful, of priorities. However, since
346 * this is pinned memory, we need to assume worst case, so
347 * that means the min(mq_maxmsg, max_priorities) * struct
348 * posix_msg_tree_node.
349 */
350
351 ret = -EINVAL;
352 if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
353 goto out_inode;
354 if (capable(CAP_SYS_RESOURCE)) {
355 if (info->attr.mq_maxmsg > HARD_MSGMAX ||
356 info->attr.mq_msgsize > HARD_MSGSIZEMAX)
357 goto out_inode;
358 } else {
359 if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
360 info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
361 goto out_inode;
362 }
363 ret = -EOVERFLOW;
364 /* check for overflow */
365 if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
366 goto out_inode;
367 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
368 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
369 sizeof(struct posix_msg_tree_node);
370 mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
371 if (mq_bytes + mq_treesize < mq_bytes)
372 goto out_inode;
373 mq_bytes += mq_treesize;
374 spin_lock(&mq_lock);
375 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
376 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
377 spin_unlock(&mq_lock);
378 /* mqueue_evict_inode() releases info->messages */
379 ret = -EMFILE;
380 goto out_inode;
381 }
382 u->mq_bytes += mq_bytes;
383 spin_unlock(&mq_lock);
384
385 /* all is ok */
386 info->user = get_uid(u);
387 } else if (S_ISDIR(mode)) {
388 inc_nlink(inode);
389 /* Some things misbehave if size == 0 on a directory */
390 inode->i_size = 2 * DIRENT_SIZE;
391 inode->i_op = &mqueue_dir_inode_operations;
392 inode->i_fop = &simple_dir_operations;
393 }
394
395 return inode;
396out_inode:
397 iput(inode);
398err:
399 return ERR_PTR(ret);
400}
401
402static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc)
403{
404 struct inode *inode;
405 struct ipc_namespace *ns = sb->s_fs_info;
406
407 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
408 sb->s_blocksize = PAGE_SIZE;
409 sb->s_blocksize_bits = PAGE_SHIFT;
410 sb->s_magic = MQUEUE_MAGIC;
411 sb->s_op = &mqueue_super_ops;
412
413 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
414 if (IS_ERR(inode))
415 return PTR_ERR(inode);
416
417 sb->s_root = d_make_root(inode);
418 if (!sb->s_root)
419 return -ENOMEM;
420 return 0;
421}
422
423static int mqueue_get_tree(struct fs_context *fc)
424{
425 struct mqueue_fs_context *ctx = fc->fs_private;
426
427 return get_tree_keyed(fc, mqueue_fill_super, ctx->ipc_ns);
428}
429
430static void mqueue_fs_context_free(struct fs_context *fc)
431{
432 struct mqueue_fs_context *ctx = fc->fs_private;
433
434 put_ipc_ns(ctx->ipc_ns);
435 kfree(ctx);
436}
437
438static int mqueue_init_fs_context(struct fs_context *fc)
439{
440 struct mqueue_fs_context *ctx;
441
442 ctx = kzalloc(sizeof(struct mqueue_fs_context), GFP_KERNEL);
443 if (!ctx)
444 return -ENOMEM;
445
446 ctx->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
447 put_user_ns(fc->user_ns);
448 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
449 fc->fs_private = ctx;
450 fc->ops = &mqueue_fs_context_ops;
451 return 0;
452}
453
454static struct vfsmount *mq_create_mount(struct ipc_namespace *ns)
455{
456 struct mqueue_fs_context *ctx;
457 struct fs_context *fc;
458 struct vfsmount *mnt;
459
460 fc = fs_context_for_mount(&mqueue_fs_type, SB_KERNMOUNT);
461 if (IS_ERR(fc))
462 return ERR_CAST(fc);
463
464 ctx = fc->fs_private;
465 put_ipc_ns(ctx->ipc_ns);
466 ctx->ipc_ns = get_ipc_ns(ns);
467 put_user_ns(fc->user_ns);
468 fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
469
470 mnt = fc_mount(fc);
471 put_fs_context(fc);
472 return mnt;
473}
474
475static void init_once(void *foo)
476{
477 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
478
479 inode_init_once(&p->vfs_inode);
480}
481
482static struct inode *mqueue_alloc_inode(struct super_block *sb)
483{
484 struct mqueue_inode_info *ei;
485
486 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
487 if (!ei)
488 return NULL;
489 return &ei->vfs_inode;
490}
491
492static void mqueue_free_inode(struct inode *inode)
493{
494 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
495}
496
497static void mqueue_evict_inode(struct inode *inode)
498{
499 struct mqueue_inode_info *info;
500 struct user_struct *user;
501 struct ipc_namespace *ipc_ns;
502 struct msg_msg *msg, *nmsg;
503 LIST_HEAD(tmp_msg);
504
505 clear_inode(inode);
506
507 if (S_ISDIR(inode->i_mode))
508 return;
509
510 ipc_ns = get_ns_from_inode(inode);
511 info = MQUEUE_I(inode);
512 spin_lock(&info->lock);
513 while ((msg = msg_get(info)) != NULL)
514 list_add_tail(&msg->m_list, &tmp_msg);
515 kfree(info->node_cache);
516 spin_unlock(&info->lock);
517
518 list_for_each_entry_safe(msg, nmsg, &tmp_msg, m_list) {
519 list_del(&msg->m_list);
520 free_msg(msg);
521 }
522
523 user = info->user;
524 if (user) {
525 unsigned long mq_bytes, mq_treesize;
526
527 /* Total amount of bytes accounted for the mqueue */
528 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
529 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
530 sizeof(struct posix_msg_tree_node);
531
532 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
533 info->attr.mq_msgsize);
534
535 spin_lock(&mq_lock);
536 user->mq_bytes -= mq_bytes;
537 /*
538 * get_ns_from_inode() ensures that the
539 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
540 * to which we now hold a reference, or it is NULL.
541 * We can't put it here under mq_lock, though.
542 */
543 if (ipc_ns)
544 ipc_ns->mq_queues_count--;
545 spin_unlock(&mq_lock);
546 free_uid(user);
547 }
548 if (ipc_ns)
549 put_ipc_ns(ipc_ns);
550}
551
552static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
553{
554 struct inode *dir = dentry->d_parent->d_inode;
555 struct inode *inode;
556 struct mq_attr *attr = arg;
557 int error;
558 struct ipc_namespace *ipc_ns;
559
560 spin_lock(&mq_lock);
561 ipc_ns = __get_ns_from_inode(dir);
562 if (!ipc_ns) {
563 error = -EACCES;
564 goto out_unlock;
565 }
566
567 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
568 !capable(CAP_SYS_RESOURCE)) {
569 error = -ENOSPC;
570 goto out_unlock;
571 }
572 ipc_ns->mq_queues_count++;
573 spin_unlock(&mq_lock);
574
575 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
576 if (IS_ERR(inode)) {
577 error = PTR_ERR(inode);
578 spin_lock(&mq_lock);
579 ipc_ns->mq_queues_count--;
580 goto out_unlock;
581 }
582
583 put_ipc_ns(ipc_ns);
584 dir->i_size += DIRENT_SIZE;
585 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
586
587 d_instantiate(dentry, inode);
588 dget(dentry);
589 return 0;
590out_unlock:
591 spin_unlock(&mq_lock);
592 if (ipc_ns)
593 put_ipc_ns(ipc_ns);
594 return error;
595}
596
597static int mqueue_create(struct inode *dir, struct dentry *dentry,
598 umode_t mode, bool excl)
599{
600 return mqueue_create_attr(dentry, mode, NULL);
601}
602
603static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
604{
605 struct inode *inode = d_inode(dentry);
606
607 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
608 dir->i_size -= DIRENT_SIZE;
609 drop_nlink(inode);
610 dput(dentry);
611 return 0;
612}
613
614/*
615* This is routine for system read from queue file.
616* To avoid mess with doing here some sort of mq_receive we allow
617* to read only queue size & notification info (the only values
618* that are interesting from user point of view and aren't accessible
619* through std routines)
620*/
621static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
622 size_t count, loff_t *off)
623{
624 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
625 char buffer[FILENT_SIZE];
626 ssize_t ret;
627
628 spin_lock(&info->lock);
629 snprintf(buffer, sizeof(buffer),
630 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
631 info->qsize,
632 info->notify_owner ? info->notify.sigev_notify : 0,
633 (info->notify_owner &&
634 info->notify.sigev_notify == SIGEV_SIGNAL) ?
635 info->notify.sigev_signo : 0,
636 pid_vnr(info->notify_owner));
637 spin_unlock(&info->lock);
638 buffer[sizeof(buffer)-1] = '\0';
639
640 ret = simple_read_from_buffer(u_data, count, off, buffer,
641 strlen(buffer));
642 if (ret <= 0)
643 return ret;
644
645 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
646 return ret;
647}
648
649static int mqueue_flush_file(struct file *filp, fl_owner_t id)
650{
651 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
652
653 spin_lock(&info->lock);
654 if (task_tgid(current) == info->notify_owner)
655 remove_notification(info);
656
657 spin_unlock(&info->lock);
658 return 0;
659}
660
661static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
662{
663 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
664 __poll_t retval = 0;
665
666 poll_wait(filp, &info->wait_q, poll_tab);
667
668 spin_lock(&info->lock);
669 if (info->attr.mq_curmsgs)
670 retval = EPOLLIN | EPOLLRDNORM;
671
672 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
673 retval |= EPOLLOUT | EPOLLWRNORM;
674 spin_unlock(&info->lock);
675
676 return retval;
677}
678
679/* Adds current to info->e_wait_q[sr] before element with smaller prio */
680static void wq_add(struct mqueue_inode_info *info, int sr,
681 struct ext_wait_queue *ewp)
682{
683 struct ext_wait_queue *walk;
684
685 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
686 if (walk->task->prio <= current->prio) {
687 list_add_tail(&ewp->list, &walk->list);
688 return;
689 }
690 }
691 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
692}
693
694/*
695 * Puts current task to sleep. Caller must hold queue lock. After return
696 * lock isn't held.
697 * sr: SEND or RECV
698 */
699static int wq_sleep(struct mqueue_inode_info *info, int sr,
700 ktime_t *timeout, struct ext_wait_queue *ewp)
701 __releases(&info->lock)
702{
703 int retval;
704 signed long time;
705
706 wq_add(info, sr, ewp);
707
708 for (;;) {
709 /* memory barrier not required, we hold info->lock */
710 __set_current_state(TASK_INTERRUPTIBLE);
711
712 spin_unlock(&info->lock);
713 time = schedule_hrtimeout_range_clock(timeout, 0,
714 HRTIMER_MODE_ABS, CLOCK_REALTIME);
715
716 if (READ_ONCE(ewp->state) == STATE_READY) {
717 /* see MQ_BARRIER for purpose/pairing */
718 smp_acquire__after_ctrl_dep();
719 retval = 0;
720 goto out;
721 }
722 spin_lock(&info->lock);
723
724 /* we hold info->lock, so no memory barrier required */
725 if (READ_ONCE(ewp->state) == STATE_READY) {
726 retval = 0;
727 goto out_unlock;
728 }
729 if (signal_pending(current)) {
730 retval = -ERESTARTSYS;
731 break;
732 }
733 if (time == 0) {
734 retval = -ETIMEDOUT;
735 break;
736 }
737 }
738 list_del(&ewp->list);
739out_unlock:
740 spin_unlock(&info->lock);
741out:
742 return retval;
743}
744
745/*
746 * Returns waiting task that should be serviced first or NULL if none exists
747 */
748static struct ext_wait_queue *wq_get_first_waiter(
749 struct mqueue_inode_info *info, int sr)
750{
751 struct list_head *ptr;
752
753 ptr = info->e_wait_q[sr].list.prev;
754 if (ptr == &info->e_wait_q[sr].list)
755 return NULL;
756 return list_entry(ptr, struct ext_wait_queue, list);
757}
758
759
760static inline void set_cookie(struct sk_buff *skb, char code)
761{
762 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
763}
764
765/*
766 * The next function is only to split too long sys_mq_timedsend
767 */
768static void __do_notify(struct mqueue_inode_info *info)
769{
770 /* notification
771 * invoked when there is registered process and there isn't process
772 * waiting synchronously for message AND state of queue changed from
773 * empty to not empty. Here we are sure that no one is waiting
774 * synchronously. */
775 if (info->notify_owner &&
776 info->attr.mq_curmsgs == 1) {
777 switch (info->notify.sigev_notify) {
778 case SIGEV_NONE:
779 break;
780 case SIGEV_SIGNAL: {
781 struct kernel_siginfo sig_i;
782 struct task_struct *task;
783
784 /* do_mq_notify() accepts sigev_signo == 0, why?? */
785 if (!info->notify.sigev_signo)
786 break;
787
788 clear_siginfo(&sig_i);
789 sig_i.si_signo = info->notify.sigev_signo;
790 sig_i.si_errno = 0;
791 sig_i.si_code = SI_MESGQ;
792 sig_i.si_value = info->notify.sigev_value;
793 rcu_read_lock();
794 /* map current pid/uid into info->owner's namespaces */
795 sig_i.si_pid = task_tgid_nr_ns(current,
796 ns_of_pid(info->notify_owner));
797 sig_i.si_uid = from_kuid_munged(info->notify_user_ns,
798 current_uid());
799 /*
800 * We can't use kill_pid_info(), this signal should
801 * bypass check_kill_permission(). It is from kernel
802 * but si_fromuser() can't know this.
803 * We do check the self_exec_id, to avoid sending
804 * signals to programs that don't expect them.
805 */
806 task = pid_task(info->notify_owner, PIDTYPE_TGID);
807 if (task && task->self_exec_id ==
808 info->notify_self_exec_id) {
809 do_send_sig_info(info->notify.sigev_signo,
810 &sig_i, task, PIDTYPE_TGID);
811 }
812 rcu_read_unlock();
813 break;
814 }
815 case SIGEV_THREAD:
816 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
817 netlink_sendskb(info->notify_sock, info->notify_cookie);
818 break;
819 }
820 /* after notification unregisters process */
821 put_pid(info->notify_owner);
822 put_user_ns(info->notify_user_ns);
823 info->notify_owner = NULL;
824 info->notify_user_ns = NULL;
825 }
826 wake_up(&info->wait_q);
827}
828
829static int prepare_timeout(const struct __kernel_timespec __user *u_abs_timeout,
830 struct timespec64 *ts)
831{
832 if (get_timespec64(ts, u_abs_timeout))
833 return -EFAULT;
834 if (!timespec64_valid(ts))
835 return -EINVAL;
836 return 0;
837}
838
839static void remove_notification(struct mqueue_inode_info *info)
840{
841 if (info->notify_owner != NULL &&
842 info->notify.sigev_notify == SIGEV_THREAD) {
843 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
844 netlink_sendskb(info->notify_sock, info->notify_cookie);
845 }
846 put_pid(info->notify_owner);
847 put_user_ns(info->notify_user_ns);
848 info->notify_owner = NULL;
849 info->notify_user_ns = NULL;
850}
851
852static int prepare_open(struct dentry *dentry, int oflag, int ro,
853 umode_t mode, struct filename *name,
854 struct mq_attr *attr)
855{
856 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
857 MAY_READ | MAY_WRITE };
858 int acc;
859
860 if (d_really_is_negative(dentry)) {
861 if (!(oflag & O_CREAT))
862 return -ENOENT;
863 if (ro)
864 return ro;
865 audit_inode_parent_hidden(name, dentry->d_parent);
866 return vfs_mkobj(dentry, mode & ~current_umask(),
867 mqueue_create_attr, attr);
868 }
869 /* it already existed */
870 audit_inode(name, dentry, 0);
871 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
872 return -EEXIST;
873 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
874 return -EINVAL;
875 acc = oflag2acc[oflag & O_ACCMODE];
876 return inode_permission(d_inode(dentry), acc);
877}
878
879static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
880 struct mq_attr *attr)
881{
882 struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
883 struct dentry *root = mnt->mnt_root;
884 struct filename *name;
885 struct path path;
886 int fd, error;
887 int ro;
888
889 audit_mq_open(oflag, mode, attr);
890
891 if (IS_ERR(name = getname(u_name)))
892 return PTR_ERR(name);
893
894 fd = get_unused_fd_flags(O_CLOEXEC);
895 if (fd < 0)
896 goto out_putname;
897
898 ro = mnt_want_write(mnt); /* we'll drop it in any case */
899 inode_lock(d_inode(root));
900 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
901 if (IS_ERR(path.dentry)) {
902 error = PTR_ERR(path.dentry);
903 goto out_putfd;
904 }
905 path.mnt = mntget(mnt);
906 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
907 if (!error) {
908 struct file *file = dentry_open(&path, oflag, current_cred());
909 if (!IS_ERR(file))
910 fd_install(fd, file);
911 else
912 error = PTR_ERR(file);
913 }
914 path_put(&path);
915out_putfd:
916 if (error) {
917 put_unused_fd(fd);
918 fd = error;
919 }
920 inode_unlock(d_inode(root));
921 if (!ro)
922 mnt_drop_write(mnt);
923out_putname:
924 putname(name);
925 return fd;
926}
927
928SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
929 struct mq_attr __user *, u_attr)
930{
931 struct mq_attr attr;
932 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
933 return -EFAULT;
934
935 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
936}
937
938SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
939{
940 int err;
941 struct filename *name;
942 struct dentry *dentry;
943 struct inode *inode = NULL;
944 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
945 struct vfsmount *mnt = ipc_ns->mq_mnt;
946
947 name = getname(u_name);
948 if (IS_ERR(name))
949 return PTR_ERR(name);
950
951 audit_inode_parent_hidden(name, mnt->mnt_root);
952 err = mnt_want_write(mnt);
953 if (err)
954 goto out_name;
955 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
956 dentry = lookup_one_len(name->name, mnt->mnt_root,
957 strlen(name->name));
958 if (IS_ERR(dentry)) {
959 err = PTR_ERR(dentry);
960 goto out_unlock;
961 }
962
963 inode = d_inode(dentry);
964 if (!inode) {
965 err = -ENOENT;
966 } else {
967 ihold(inode);
968 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
969 }
970 dput(dentry);
971
972out_unlock:
973 inode_unlock(d_inode(mnt->mnt_root));
974 if (inode)
975 iput(inode);
976 mnt_drop_write(mnt);
977out_name:
978 putname(name);
979
980 return err;
981}
982
983/* Pipelined send and receive functions.
984 *
985 * If a receiver finds no waiting message, then it registers itself in the
986 * list of waiting receivers. A sender checks that list before adding the new
987 * message into the message array. If there is a waiting receiver, then it
988 * bypasses the message array and directly hands the message over to the
989 * receiver. The receiver accepts the message and returns without grabbing the
990 * queue spinlock:
991 *
992 * - Set pointer to message.
993 * - Queue the receiver task for later wakeup (without the info->lock).
994 * - Update its state to STATE_READY. Now the receiver can continue.
995 * - Wake up the process after the lock is dropped. Should the process wake up
996 * before this wakeup (due to a timeout or a signal) it will either see
997 * STATE_READY and continue or acquire the lock to check the state again.
998 *
999 * The same algorithm is used for senders.
1000 */
1001
1002static inline void __pipelined_op(struct wake_q_head *wake_q,
1003 struct mqueue_inode_info *info,
1004 struct ext_wait_queue *this)
1005{
1006 list_del(&this->list);
1007 get_task_struct(this->task);
1008
1009 /* see MQ_BARRIER for purpose/pairing */
1010 smp_store_release(&this->state, STATE_READY);
1011 wake_q_add_safe(wake_q, this->task);
1012}
1013
1014/* pipelined_send() - send a message directly to the task waiting in
1015 * sys_mq_timedreceive() (without inserting message into a queue).
1016 */
1017static inline void pipelined_send(struct wake_q_head *wake_q,
1018 struct mqueue_inode_info *info,
1019 struct msg_msg *message,
1020 struct ext_wait_queue *receiver)
1021{
1022 receiver->msg = message;
1023 __pipelined_op(wake_q, info, receiver);
1024}
1025
1026/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
1027 * gets its message and put to the queue (we have one free place for sure). */
1028static inline void pipelined_receive(struct wake_q_head *wake_q,
1029 struct mqueue_inode_info *info)
1030{
1031 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
1032
1033 if (!sender) {
1034 /* for poll */
1035 wake_up_interruptible(&info->wait_q);
1036 return;
1037 }
1038 if (msg_insert(sender->msg, info))
1039 return;
1040
1041 __pipelined_op(wake_q, info, sender);
1042}
1043
1044static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
1045 size_t msg_len, unsigned int msg_prio,
1046 struct timespec64 *ts)
1047{
1048 struct fd f;
1049 struct inode *inode;
1050 struct ext_wait_queue wait;
1051 struct ext_wait_queue *receiver;
1052 struct msg_msg *msg_ptr;
1053 struct mqueue_inode_info *info;
1054 ktime_t expires, *timeout = NULL;
1055 struct posix_msg_tree_node *new_leaf = NULL;
1056 int ret = 0;
1057 DEFINE_WAKE_Q(wake_q);
1058
1059 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
1060 return -EINVAL;
1061
1062 if (ts) {
1063 expires = timespec64_to_ktime(*ts);
1064 timeout = &expires;
1065 }
1066
1067 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
1068
1069 f = fdget(mqdes);
1070 if (unlikely(!f.file)) {
1071 ret = -EBADF;
1072 goto out;
1073 }
1074
1075 inode = file_inode(f.file);
1076 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1077 ret = -EBADF;
1078 goto out_fput;
1079 }
1080 info = MQUEUE_I(inode);
1081 audit_file(f.file);
1082
1083 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
1084 ret = -EBADF;
1085 goto out_fput;
1086 }
1087
1088 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1089 ret = -EMSGSIZE;
1090 goto out_fput;
1091 }
1092
1093 /* First try to allocate memory, before doing anything with
1094 * existing queues. */
1095 msg_ptr = load_msg(u_msg_ptr, msg_len);
1096 if (IS_ERR(msg_ptr)) {
1097 ret = PTR_ERR(msg_ptr);
1098 goto out_fput;
1099 }
1100 msg_ptr->m_ts = msg_len;
1101 msg_ptr->m_type = msg_prio;
1102
1103 /*
1104 * msg_insert really wants us to have a valid, spare node struct so
1105 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1106 * fall back to that if necessary.
1107 */
1108 if (!info->node_cache)
1109 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1110
1111 spin_lock(&info->lock);
1112
1113 if (!info->node_cache && new_leaf) {
1114 /* Save our speculative allocation into the cache */
1115 INIT_LIST_HEAD(&new_leaf->msg_list);
1116 info->node_cache = new_leaf;
1117 new_leaf = NULL;
1118 } else {
1119 kfree(new_leaf);
1120 }
1121
1122 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1123 if (f.file->f_flags & O_NONBLOCK) {
1124 ret = -EAGAIN;
1125 } else {
1126 wait.task = current;
1127 wait.msg = (void *) msg_ptr;
1128
1129 /* memory barrier not required, we hold info->lock */
1130 WRITE_ONCE(wait.state, STATE_NONE);
1131 ret = wq_sleep(info, SEND, timeout, &wait);
1132 /*
1133 * wq_sleep must be called with info->lock held, and
1134 * returns with the lock released
1135 */
1136 goto out_free;
1137 }
1138 } else {
1139 receiver = wq_get_first_waiter(info, RECV);
1140 if (receiver) {
1141 pipelined_send(&wake_q, info, msg_ptr, receiver);
1142 } else {
1143 /* adds message to the queue */
1144 ret = msg_insert(msg_ptr, info);
1145 if (ret)
1146 goto out_unlock;
1147 __do_notify(info);
1148 }
1149 inode->i_atime = inode->i_mtime = inode->i_ctime =
1150 current_time(inode);
1151 }
1152out_unlock:
1153 spin_unlock(&info->lock);
1154 wake_up_q(&wake_q);
1155out_free:
1156 if (ret)
1157 free_msg(msg_ptr);
1158out_fput:
1159 fdput(f);
1160out:
1161 return ret;
1162}
1163
1164static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1165 size_t msg_len, unsigned int __user *u_msg_prio,
1166 struct timespec64 *ts)
1167{
1168 ssize_t ret;
1169 struct msg_msg *msg_ptr;
1170 struct fd f;
1171 struct inode *inode;
1172 struct mqueue_inode_info *info;
1173 struct ext_wait_queue wait;
1174 ktime_t expires, *timeout = NULL;
1175 struct posix_msg_tree_node *new_leaf = NULL;
1176
1177 if (ts) {
1178 expires = timespec64_to_ktime(*ts);
1179 timeout = &expires;
1180 }
1181
1182 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1183
1184 f = fdget(mqdes);
1185 if (unlikely(!f.file)) {
1186 ret = -EBADF;
1187 goto out;
1188 }
1189
1190 inode = file_inode(f.file);
1191 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1192 ret = -EBADF;
1193 goto out_fput;
1194 }
1195 info = MQUEUE_I(inode);
1196 audit_file(f.file);
1197
1198 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1199 ret = -EBADF;
1200 goto out_fput;
1201 }
1202
1203 /* checks if buffer is big enough */
1204 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1205 ret = -EMSGSIZE;
1206 goto out_fput;
1207 }
1208
1209 /*
1210 * msg_insert really wants us to have a valid, spare node struct so
1211 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1212 * fall back to that if necessary.
1213 */
1214 if (!info->node_cache)
1215 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1216
1217 spin_lock(&info->lock);
1218
1219 if (!info->node_cache && new_leaf) {
1220 /* Save our speculative allocation into the cache */
1221 INIT_LIST_HEAD(&new_leaf->msg_list);
1222 info->node_cache = new_leaf;
1223 } else {
1224 kfree(new_leaf);
1225 }
1226
1227 if (info->attr.mq_curmsgs == 0) {
1228 if (f.file->f_flags & O_NONBLOCK) {
1229 spin_unlock(&info->lock);
1230 ret = -EAGAIN;
1231 } else {
1232 wait.task = current;
1233
1234 /* memory barrier not required, we hold info->lock */
1235 WRITE_ONCE(wait.state, STATE_NONE);
1236 ret = wq_sleep(info, RECV, timeout, &wait);
1237 msg_ptr = wait.msg;
1238 }
1239 } else {
1240 DEFINE_WAKE_Q(wake_q);
1241
1242 msg_ptr = msg_get(info);
1243
1244 inode->i_atime = inode->i_mtime = inode->i_ctime =
1245 current_time(inode);
1246
1247 /* There is now free space in queue. */
1248 pipelined_receive(&wake_q, info);
1249 spin_unlock(&info->lock);
1250 wake_up_q(&wake_q);
1251 ret = 0;
1252 }
1253 if (ret == 0) {
1254 ret = msg_ptr->m_ts;
1255
1256 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1257 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1258 ret = -EFAULT;
1259 }
1260 free_msg(msg_ptr);
1261 }
1262out_fput:
1263 fdput(f);
1264out:
1265 return ret;
1266}
1267
1268SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1269 size_t, msg_len, unsigned int, msg_prio,
1270 const struct __kernel_timespec __user *, u_abs_timeout)
1271{
1272 struct timespec64 ts, *p = NULL;
1273 if (u_abs_timeout) {
1274 int res = prepare_timeout(u_abs_timeout, &ts);
1275 if (res)
1276 return res;
1277 p = &ts;
1278 }
1279 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1280}
1281
1282SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1283 size_t, msg_len, unsigned int __user *, u_msg_prio,
1284 const struct __kernel_timespec __user *, u_abs_timeout)
1285{
1286 struct timespec64 ts, *p = NULL;
1287 if (u_abs_timeout) {
1288 int res = prepare_timeout(u_abs_timeout, &ts);
1289 if (res)
1290 return res;
1291 p = &ts;
1292 }
1293 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1294}
1295
1296/*
1297 * Notes: the case when user wants us to deregister (with NULL as pointer)
1298 * and he isn't currently owner of notification, will be silently discarded.
1299 * It isn't explicitly defined in the POSIX.
1300 */
1301static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1302{
1303 int ret;
1304 struct fd f;
1305 struct sock *sock;
1306 struct inode *inode;
1307 struct mqueue_inode_info *info;
1308 struct sk_buff *nc;
1309
1310 audit_mq_notify(mqdes, notification);
1311
1312 nc = NULL;
1313 sock = NULL;
1314 if (notification != NULL) {
1315 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1316 notification->sigev_notify != SIGEV_SIGNAL &&
1317 notification->sigev_notify != SIGEV_THREAD))
1318 return -EINVAL;
1319 if (notification->sigev_notify == SIGEV_SIGNAL &&
1320 !valid_signal(notification->sigev_signo)) {
1321 return -EINVAL;
1322 }
1323 if (notification->sigev_notify == SIGEV_THREAD) {
1324 long timeo;
1325
1326 /* create the notify skb */
1327 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1328 if (!nc)
1329 return -ENOMEM;
1330
1331 if (copy_from_user(nc->data,
1332 notification->sigev_value.sival_ptr,
1333 NOTIFY_COOKIE_LEN)) {
1334 ret = -EFAULT;
1335 goto free_skb;
1336 }
1337
1338 /* TODO: add a header? */
1339 skb_put(nc, NOTIFY_COOKIE_LEN);
1340 /* and attach it to the socket */
1341retry:
1342 f = fdget(notification->sigev_signo);
1343 if (!f.file) {
1344 ret = -EBADF;
1345 goto out;
1346 }
1347 sock = netlink_getsockbyfilp(f.file);
1348 fdput(f);
1349 if (IS_ERR(sock)) {
1350 ret = PTR_ERR(sock);
1351 goto free_skb;
1352 }
1353
1354 timeo = MAX_SCHEDULE_TIMEOUT;
1355 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1356 if (ret == 1) {
1357 sock = NULL;
1358 goto retry;
1359 }
1360 if (ret)
1361 return ret;
1362 }
1363 }
1364
1365 f = fdget(mqdes);
1366 if (!f.file) {
1367 ret = -EBADF;
1368 goto out;
1369 }
1370
1371 inode = file_inode(f.file);
1372 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1373 ret = -EBADF;
1374 goto out_fput;
1375 }
1376 info = MQUEUE_I(inode);
1377
1378 ret = 0;
1379 spin_lock(&info->lock);
1380 if (notification == NULL) {
1381 if (info->notify_owner == task_tgid(current)) {
1382 remove_notification(info);
1383 inode->i_atime = inode->i_ctime = current_time(inode);
1384 }
1385 } else if (info->notify_owner != NULL) {
1386 ret = -EBUSY;
1387 } else {
1388 switch (notification->sigev_notify) {
1389 case SIGEV_NONE:
1390 info->notify.sigev_notify = SIGEV_NONE;
1391 break;
1392 case SIGEV_THREAD:
1393 info->notify_sock = sock;
1394 info->notify_cookie = nc;
1395 sock = NULL;
1396 nc = NULL;
1397 info->notify.sigev_notify = SIGEV_THREAD;
1398 break;
1399 case SIGEV_SIGNAL:
1400 info->notify.sigev_signo = notification->sigev_signo;
1401 info->notify.sigev_value = notification->sigev_value;
1402 info->notify.sigev_notify = SIGEV_SIGNAL;
1403 info->notify_self_exec_id = current->self_exec_id;
1404 break;
1405 }
1406
1407 info->notify_owner = get_pid(task_tgid(current));
1408 info->notify_user_ns = get_user_ns(current_user_ns());
1409 inode->i_atime = inode->i_ctime = current_time(inode);
1410 }
1411 spin_unlock(&info->lock);
1412out_fput:
1413 fdput(f);
1414out:
1415 if (sock)
1416 netlink_detachskb(sock, nc);
1417 else
1418free_skb:
1419 dev_kfree_skb(nc);
1420
1421 return ret;
1422}
1423
1424SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1425 const struct sigevent __user *, u_notification)
1426{
1427 struct sigevent n, *p = NULL;
1428 if (u_notification) {
1429 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1430 return -EFAULT;
1431 p = &n;
1432 }
1433 return do_mq_notify(mqdes, p);
1434}
1435
1436static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1437{
1438 struct fd f;
1439 struct inode *inode;
1440 struct mqueue_inode_info *info;
1441
1442 if (new && (new->mq_flags & (~O_NONBLOCK)))
1443 return -EINVAL;
1444
1445 f = fdget(mqdes);
1446 if (!f.file)
1447 return -EBADF;
1448
1449 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1450 fdput(f);
1451 return -EBADF;
1452 }
1453
1454 inode = file_inode(f.file);
1455 info = MQUEUE_I(inode);
1456
1457 spin_lock(&info->lock);
1458
1459 if (old) {
1460 *old = info->attr;
1461 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1462 }
1463 if (new) {
1464 audit_mq_getsetattr(mqdes, new);
1465 spin_lock(&f.file->f_lock);
1466 if (new->mq_flags & O_NONBLOCK)
1467 f.file->f_flags |= O_NONBLOCK;
1468 else
1469 f.file->f_flags &= ~O_NONBLOCK;
1470 spin_unlock(&f.file->f_lock);
1471
1472 inode->i_atime = inode->i_ctime = current_time(inode);
1473 }
1474
1475 spin_unlock(&info->lock);
1476 fdput(f);
1477 return 0;
1478}
1479
1480SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1481 const struct mq_attr __user *, u_mqstat,
1482 struct mq_attr __user *, u_omqstat)
1483{
1484 int ret;
1485 struct mq_attr mqstat, omqstat;
1486 struct mq_attr *new = NULL, *old = NULL;
1487
1488 if (u_mqstat) {
1489 new = &mqstat;
1490 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1491 return -EFAULT;
1492 }
1493 if (u_omqstat)
1494 old = &omqstat;
1495
1496 ret = do_mq_getsetattr(mqdes, new, old);
1497 if (ret || !old)
1498 return ret;
1499
1500 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1501 return -EFAULT;
1502 return 0;
1503}
1504
1505#ifdef CONFIG_COMPAT
1506
1507struct compat_mq_attr {
1508 compat_long_t mq_flags; /* message queue flags */
1509 compat_long_t mq_maxmsg; /* maximum number of messages */
1510 compat_long_t mq_msgsize; /* maximum message size */
1511 compat_long_t mq_curmsgs; /* number of messages currently queued */
1512 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1513};
1514
1515static inline int get_compat_mq_attr(struct mq_attr *attr,
1516 const struct compat_mq_attr __user *uattr)
1517{
1518 struct compat_mq_attr v;
1519
1520 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1521 return -EFAULT;
1522
1523 memset(attr, 0, sizeof(*attr));
1524 attr->mq_flags = v.mq_flags;
1525 attr->mq_maxmsg = v.mq_maxmsg;
1526 attr->mq_msgsize = v.mq_msgsize;
1527 attr->mq_curmsgs = v.mq_curmsgs;
1528 return 0;
1529}
1530
1531static inline int put_compat_mq_attr(const struct mq_attr *attr,
1532 struct compat_mq_attr __user *uattr)
1533{
1534 struct compat_mq_attr v;
1535
1536 memset(&v, 0, sizeof(v));
1537 v.mq_flags = attr->mq_flags;
1538 v.mq_maxmsg = attr->mq_maxmsg;
1539 v.mq_msgsize = attr->mq_msgsize;
1540 v.mq_curmsgs = attr->mq_curmsgs;
1541 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1542 return -EFAULT;
1543 return 0;
1544}
1545
1546COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1547 int, oflag, compat_mode_t, mode,
1548 struct compat_mq_attr __user *, u_attr)
1549{
1550 struct mq_attr attr, *p = NULL;
1551 if (u_attr && oflag & O_CREAT) {
1552 p = &attr;
1553 if (get_compat_mq_attr(&attr, u_attr))
1554 return -EFAULT;
1555 }
1556 return do_mq_open(u_name, oflag, mode, p);
1557}
1558
1559COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1560 const struct compat_sigevent __user *, u_notification)
1561{
1562 struct sigevent n, *p = NULL;
1563 if (u_notification) {
1564 if (get_compat_sigevent(&n, u_notification))
1565 return -EFAULT;
1566 if (n.sigev_notify == SIGEV_THREAD)
1567 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1568 p = &n;
1569 }
1570 return do_mq_notify(mqdes, p);
1571}
1572
1573COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1574 const struct compat_mq_attr __user *, u_mqstat,
1575 struct compat_mq_attr __user *, u_omqstat)
1576{
1577 int ret;
1578 struct mq_attr mqstat, omqstat;
1579 struct mq_attr *new = NULL, *old = NULL;
1580
1581 if (u_mqstat) {
1582 new = &mqstat;
1583 if (get_compat_mq_attr(new, u_mqstat))
1584 return -EFAULT;
1585 }
1586 if (u_omqstat)
1587 old = &omqstat;
1588
1589 ret = do_mq_getsetattr(mqdes, new, old);
1590 if (ret || !old)
1591 return ret;
1592
1593 if (put_compat_mq_attr(old, u_omqstat))
1594 return -EFAULT;
1595 return 0;
1596}
1597#endif
1598
1599#ifdef CONFIG_COMPAT_32BIT_TIME
1600static int compat_prepare_timeout(const struct old_timespec32 __user *p,
1601 struct timespec64 *ts)
1602{
1603 if (get_old_timespec32(ts, p))
1604 return -EFAULT;
1605 if (!timespec64_valid(ts))
1606 return -EINVAL;
1607 return 0;
1608}
1609
1610SYSCALL_DEFINE5(mq_timedsend_time32, mqd_t, mqdes,
1611 const char __user *, u_msg_ptr,
1612 unsigned int, msg_len, unsigned int, msg_prio,
1613 const struct old_timespec32 __user *, u_abs_timeout)
1614{
1615 struct timespec64 ts, *p = NULL;
1616 if (u_abs_timeout) {
1617 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1618 if (res)
1619 return res;
1620 p = &ts;
1621 }
1622 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1623}
1624
1625SYSCALL_DEFINE5(mq_timedreceive_time32, mqd_t, mqdes,
1626 char __user *, u_msg_ptr,
1627 unsigned int, msg_len, unsigned int __user *, u_msg_prio,
1628 const struct old_timespec32 __user *, u_abs_timeout)
1629{
1630 struct timespec64 ts, *p = NULL;
1631 if (u_abs_timeout) {
1632 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1633 if (res)
1634 return res;
1635 p = &ts;
1636 }
1637 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1638}
1639#endif
1640
1641static const struct inode_operations mqueue_dir_inode_operations = {
1642 .lookup = simple_lookup,
1643 .create = mqueue_create,
1644 .unlink = mqueue_unlink,
1645};
1646
1647static const struct file_operations mqueue_file_operations = {
1648 .flush = mqueue_flush_file,
1649 .poll = mqueue_poll_file,
1650 .read = mqueue_read_file,
1651 .llseek = default_llseek,
1652};
1653
1654static const struct super_operations mqueue_super_ops = {
1655 .alloc_inode = mqueue_alloc_inode,
1656 .free_inode = mqueue_free_inode,
1657 .evict_inode = mqueue_evict_inode,
1658 .statfs = simple_statfs,
1659};
1660
1661static const struct fs_context_operations mqueue_fs_context_ops = {
1662 .free = mqueue_fs_context_free,
1663 .get_tree = mqueue_get_tree,
1664};
1665
1666static struct file_system_type mqueue_fs_type = {
1667 .name = "mqueue",
1668 .init_fs_context = mqueue_init_fs_context,
1669 .kill_sb = kill_litter_super,
1670 .fs_flags = FS_USERNS_MOUNT,
1671};
1672
1673int mq_init_ns(struct ipc_namespace *ns)
1674{
1675 struct vfsmount *m;
1676
1677 ns->mq_queues_count = 0;
1678 ns->mq_queues_max = DFLT_QUEUESMAX;
1679 ns->mq_msg_max = DFLT_MSGMAX;
1680 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1681 ns->mq_msg_default = DFLT_MSG;
1682 ns->mq_msgsize_default = DFLT_MSGSIZE;
1683
1684 m = mq_create_mount(ns);
1685 if (IS_ERR(m))
1686 return PTR_ERR(m);
1687 ns->mq_mnt = m;
1688 return 0;
1689}
1690
1691void mq_clear_sbinfo(struct ipc_namespace *ns)
1692{
1693 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1694}
1695
1696void mq_put_mnt(struct ipc_namespace *ns)
1697{
1698 kern_unmount(ns->mq_mnt);
1699}
1700
1701static int __init init_mqueue_fs(void)
1702{
1703 int error;
1704
1705 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1706 sizeof(struct mqueue_inode_info), 0,
1707 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1708 if (mqueue_inode_cachep == NULL)
1709 return -ENOMEM;
1710
1711 /* ignore failures - they are not fatal */
1712 mq_sysctl_table = mq_register_sysctl_table();
1713
1714 error = register_filesystem(&mqueue_fs_type);
1715 if (error)
1716 goto out_sysctl;
1717
1718 spin_lock_init(&mq_lock);
1719
1720 error = mq_init_ns(&init_ipc_ns);
1721 if (error)
1722 goto out_filesystem;
1723
1724 return 0;
1725
1726out_filesystem:
1727 unregister_filesystem(&mqueue_fs_type);
1728out_sysctl:
1729 if (mq_sysctl_table)
1730 unregister_sysctl_table(mq_sysctl_table);
1731 kmem_cache_destroy(mqueue_inode_cachep);
1732 return error;
1733}
1734
1735device_initcall(init_mqueue_fs);