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
39 #include <net/sock.h>
40 #include "util.h"
41
42 #define MQUEUE_MAGIC 0x19800202
43 #define DIRENT_SIZE 20
44 #define FILENT_SIZE 80
45
46 #define SEND 0
47 #define RECV 1
48
49 #define STATE_NONE 0
50 #define STATE_READY 1
51
52 struct posix_msg_tree_node {
53 struct rb_node rb_node;
54 struct list_head msg_list;
55 int priority;
56 };
57
58 struct ext_wait_queue { /* queue of sleeping tasks */
59 struct task_struct *task;
60 struct list_head list;
61 struct msg_msg *msg; /* ptr of loaded message */
62 int state; /* one of STATE_* values */
63 };
64
65 struct mqueue_inode_info {
66 spinlock_t lock;
67 struct inode vfs_inode;
68 wait_queue_head_t wait_q;
69
70 struct rb_root msg_tree;
71 struct posix_msg_tree_node *node_cache;
72 struct mq_attr attr;
73
74 struct sigevent notify;
75 struct pid *notify_owner;
76 struct user_namespace *notify_user_ns;
77 struct user_struct *user; /* user who created, for accounting */
78 struct sock *notify_sock;
79 struct sk_buff *notify_cookie;
80
81 /* for tasks waiting for free space and messages, respectively */
82 struct ext_wait_queue e_wait_q[2];
83
84 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
85 };
86
87 static const struct inode_operations mqueue_dir_inode_operations;
88 static const struct file_operations mqueue_file_operations;
89 static const struct super_operations mqueue_super_ops;
90 static void remove_notification(struct mqueue_inode_info *info);
91
92 static struct kmem_cache *mqueue_inode_cachep;
93
94 static struct ctl_table_header *mq_sysctl_table;
95
MQUEUE_I(struct inode * inode)96 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
97 {
98 return container_of(inode, struct mqueue_inode_info, vfs_inode);
99 }
100
101 /*
102 * This routine should be called with the mq_lock held.
103 */
__get_ns_from_inode(struct inode * inode)104 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
105 {
106 return get_ipc_ns(inode->i_sb->s_fs_info);
107 }
108
get_ns_from_inode(struct inode * inode)109 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
110 {
111 struct ipc_namespace *ns;
112
113 spin_lock(&mq_lock);
114 ns = __get_ns_from_inode(inode);
115 spin_unlock(&mq_lock);
116 return ns;
117 }
118
119 /* Auxiliary functions to manipulate messages' list */
msg_insert(struct msg_msg * msg,struct mqueue_inode_info * info)120 static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
121 {
122 struct rb_node **p, *parent = NULL;
123 struct posix_msg_tree_node *leaf;
124
125 p = &info->msg_tree.rb_node;
126 while (*p) {
127 parent = *p;
128 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
129
130 if (likely(leaf->priority == msg->m_type))
131 goto insert_msg;
132 else if (msg->m_type < leaf->priority)
133 p = &(*p)->rb_left;
134 else
135 p = &(*p)->rb_right;
136 }
137 if (info->node_cache) {
138 leaf = info->node_cache;
139 info->node_cache = NULL;
140 } else {
141 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
142 if (!leaf)
143 return -ENOMEM;
144 INIT_LIST_HEAD(&leaf->msg_list);
145 }
146 leaf->priority = msg->m_type;
147 rb_link_node(&leaf->rb_node, parent, p);
148 rb_insert_color(&leaf->rb_node, &info->msg_tree);
149 insert_msg:
150 info->attr.mq_curmsgs++;
151 info->qsize += msg->m_ts;
152 list_add_tail(&msg->m_list, &leaf->msg_list);
153 return 0;
154 }
155
msg_get(struct mqueue_inode_info * info)156 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
157 {
158 struct rb_node **p, *parent = NULL;
159 struct posix_msg_tree_node *leaf;
160 struct msg_msg *msg;
161
162 try_again:
163 p = &info->msg_tree.rb_node;
164 while (*p) {
165 parent = *p;
166 /*
167 * During insert, low priorities go to the left and high to the
168 * right. On receive, we want the highest priorities first, so
169 * walk all the way to the right.
170 */
171 p = &(*p)->rb_right;
172 }
173 if (!parent) {
174 if (info->attr.mq_curmsgs) {
175 pr_warn_once("Inconsistency in POSIX message queue, "
176 "no tree element, but supposedly messages "
177 "should exist!\n");
178 info->attr.mq_curmsgs = 0;
179 }
180 return NULL;
181 }
182 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
183 if (unlikely(list_empty(&leaf->msg_list))) {
184 pr_warn_once("Inconsistency in POSIX message queue, "
185 "empty leaf node but we haven't implemented "
186 "lazy leaf delete!\n");
187 rb_erase(&leaf->rb_node, &info->msg_tree);
188 if (info->node_cache) {
189 kfree(leaf);
190 } else {
191 info->node_cache = leaf;
192 }
193 goto try_again;
194 } else {
195 msg = list_first_entry(&leaf->msg_list,
196 struct msg_msg, m_list);
197 list_del(&msg->m_list);
198 if (list_empty(&leaf->msg_list)) {
199 rb_erase(&leaf->rb_node, &info->msg_tree);
200 if (info->node_cache) {
201 kfree(leaf);
202 } else {
203 info->node_cache = leaf;
204 }
205 }
206 }
207 info->attr.mq_curmsgs--;
208 info->qsize -= msg->m_ts;
209 return msg;
210 }
211
mqueue_get_inode(struct super_block * sb,struct ipc_namespace * ipc_ns,umode_t mode,struct mq_attr * attr)212 static struct inode *mqueue_get_inode(struct super_block *sb,
213 struct ipc_namespace *ipc_ns, umode_t mode,
214 struct mq_attr *attr)
215 {
216 struct user_struct *u = current_user();
217 struct inode *inode;
218 int ret = -ENOMEM;
219
220 inode = new_inode(sb);
221 if (!inode)
222 goto err;
223
224 inode->i_ino = get_next_ino();
225 inode->i_mode = mode;
226 inode->i_uid = current_fsuid();
227 inode->i_gid = current_fsgid();
228 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
229
230 if (S_ISREG(mode)) {
231 struct mqueue_inode_info *info;
232 unsigned long mq_bytes, mq_treesize;
233
234 inode->i_fop = &mqueue_file_operations;
235 inode->i_size = FILENT_SIZE;
236 /* mqueue specific info */
237 info = MQUEUE_I(inode);
238 spin_lock_init(&info->lock);
239 init_waitqueue_head(&info->wait_q);
240 INIT_LIST_HEAD(&info->e_wait_q[0].list);
241 INIT_LIST_HEAD(&info->e_wait_q[1].list);
242 info->notify_owner = NULL;
243 info->notify_user_ns = NULL;
244 info->qsize = 0;
245 info->user = NULL; /* set when all is ok */
246 info->msg_tree = RB_ROOT;
247 info->node_cache = NULL;
248 memset(&info->attr, 0, sizeof(info->attr));
249 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
250 ipc_ns->mq_msg_default);
251 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
252 ipc_ns->mq_msgsize_default);
253 if (attr) {
254 info->attr.mq_maxmsg = attr->mq_maxmsg;
255 info->attr.mq_msgsize = attr->mq_msgsize;
256 }
257 /*
258 * We used to allocate a static array of pointers and account
259 * the size of that array as well as one msg_msg struct per
260 * possible message into the queue size. That's no longer
261 * accurate as the queue is now an rbtree and will grow and
262 * shrink depending on usage patterns. We can, however, still
263 * account one msg_msg struct per message, but the nodes are
264 * allocated depending on priority usage, and most programs
265 * only use one, or a handful, of priorities. However, since
266 * this is pinned memory, we need to assume worst case, so
267 * that means the min(mq_maxmsg, max_priorities) * struct
268 * posix_msg_tree_node.
269 */
270 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
271 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
272 sizeof(struct posix_msg_tree_node);
273
274 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
275 info->attr.mq_msgsize);
276
277 spin_lock(&mq_lock);
278 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
279 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
280 spin_unlock(&mq_lock);
281 /* mqueue_evict_inode() releases info->messages */
282 ret = -EMFILE;
283 goto out_inode;
284 }
285 u->mq_bytes += mq_bytes;
286 spin_unlock(&mq_lock);
287
288 /* all is ok */
289 info->user = get_uid(u);
290 } else if (S_ISDIR(mode)) {
291 inc_nlink(inode);
292 /* Some things misbehave if size == 0 on a directory */
293 inode->i_size = 2 * DIRENT_SIZE;
294 inode->i_op = &mqueue_dir_inode_operations;
295 inode->i_fop = &simple_dir_operations;
296 }
297
298 return inode;
299 out_inode:
300 iput(inode);
301 err:
302 return ERR_PTR(ret);
303 }
304
mqueue_fill_super(struct super_block * sb,void * data,int silent)305 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
306 {
307 struct inode *inode;
308 struct ipc_namespace *ns = data;
309
310 sb->s_blocksize = PAGE_CACHE_SIZE;
311 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
312 sb->s_magic = MQUEUE_MAGIC;
313 sb->s_op = &mqueue_super_ops;
314
315 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
316 if (IS_ERR(inode))
317 return PTR_ERR(inode);
318
319 sb->s_root = d_make_root(inode);
320 if (!sb->s_root)
321 return -ENOMEM;
322 return 0;
323 }
324
mqueue_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)325 static struct dentry *mqueue_mount(struct file_system_type *fs_type,
326 int flags, const char *dev_name,
327 void *data)
328 {
329 if (!(flags & MS_KERNMOUNT)) {
330 struct ipc_namespace *ns = current->nsproxy->ipc_ns;
331 /* Don't allow mounting unless the caller has CAP_SYS_ADMIN
332 * over the ipc namespace.
333 */
334 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
335 return ERR_PTR(-EPERM);
336
337 data = ns;
338 }
339 return mount_ns(fs_type, flags, data, mqueue_fill_super);
340 }
341
init_once(void * foo)342 static void init_once(void *foo)
343 {
344 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
345
346 inode_init_once(&p->vfs_inode);
347 }
348
mqueue_alloc_inode(struct super_block * sb)349 static struct inode *mqueue_alloc_inode(struct super_block *sb)
350 {
351 struct mqueue_inode_info *ei;
352
353 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
354 if (!ei)
355 return NULL;
356 return &ei->vfs_inode;
357 }
358
mqueue_i_callback(struct rcu_head * head)359 static void mqueue_i_callback(struct rcu_head *head)
360 {
361 struct inode *inode = container_of(head, struct inode, i_rcu);
362 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
363 }
364
mqueue_destroy_inode(struct inode * inode)365 static void mqueue_destroy_inode(struct inode *inode)
366 {
367 call_rcu(&inode->i_rcu, mqueue_i_callback);
368 }
369
mqueue_evict_inode(struct inode * inode)370 static void mqueue_evict_inode(struct inode *inode)
371 {
372 struct mqueue_inode_info *info;
373 struct user_struct *user;
374 struct ipc_namespace *ipc_ns;
375 struct msg_msg *msg, *nmsg;
376 LIST_HEAD(tmp_msg);
377
378 clear_inode(inode);
379
380 if (S_ISDIR(inode->i_mode))
381 return;
382
383 ipc_ns = get_ns_from_inode(inode);
384 info = MQUEUE_I(inode);
385 spin_lock(&info->lock);
386 while ((msg = msg_get(info)) != NULL)
387 list_add_tail(&msg->m_list, &tmp_msg);
388 kfree(info->node_cache);
389 spin_unlock(&info->lock);
390
391 list_for_each_entry_safe(msg, nmsg, &tmp_msg, m_list) {
392 list_del(&msg->m_list);
393 free_msg(msg);
394 }
395
396 user = info->user;
397 if (user) {
398 unsigned long mq_bytes, mq_treesize;
399
400 /* Total amount of bytes accounted for the mqueue */
401 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
402 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
403 sizeof(struct posix_msg_tree_node);
404
405 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
406 info->attr.mq_msgsize);
407
408 spin_lock(&mq_lock);
409 user->mq_bytes -= mq_bytes;
410 /*
411 * get_ns_from_inode() ensures that the
412 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
413 * to which we now hold a reference, or it is NULL.
414 * We can't put it here under mq_lock, though.
415 */
416 if (ipc_ns)
417 ipc_ns->mq_queues_count--;
418 spin_unlock(&mq_lock);
419 free_uid(user);
420 }
421 if (ipc_ns)
422 put_ipc_ns(ipc_ns);
423 }
424
mqueue_create(struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)425 static int mqueue_create(struct inode *dir, struct dentry *dentry,
426 umode_t mode, bool excl)
427 {
428 struct inode *inode;
429 struct mq_attr *attr = dentry->d_fsdata;
430 int error;
431 struct ipc_namespace *ipc_ns;
432
433 spin_lock(&mq_lock);
434 ipc_ns = __get_ns_from_inode(dir);
435 if (!ipc_ns) {
436 error = -EACCES;
437 goto out_unlock;
438 }
439
440 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
441 !capable(CAP_SYS_RESOURCE)) {
442 error = -ENOSPC;
443 goto out_unlock;
444 }
445 ipc_ns->mq_queues_count++;
446 spin_unlock(&mq_lock);
447
448 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
449 if (IS_ERR(inode)) {
450 error = PTR_ERR(inode);
451 spin_lock(&mq_lock);
452 ipc_ns->mq_queues_count--;
453 goto out_unlock;
454 }
455
456 put_ipc_ns(ipc_ns);
457 dir->i_size += DIRENT_SIZE;
458 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
459
460 d_instantiate(dentry, inode);
461 dget(dentry);
462 return 0;
463 out_unlock:
464 spin_unlock(&mq_lock);
465 if (ipc_ns)
466 put_ipc_ns(ipc_ns);
467 return error;
468 }
469
mqueue_unlink(struct inode * dir,struct dentry * dentry)470 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
471 {
472 struct inode *inode = d_inode(dentry);
473
474 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
475 dir->i_size -= DIRENT_SIZE;
476 drop_nlink(inode);
477 dput(dentry);
478 return 0;
479 }
480
481 /*
482 * This is routine for system read from queue file.
483 * To avoid mess with doing here some sort of mq_receive we allow
484 * to read only queue size & notification info (the only values
485 * that are interesting from user point of view and aren't accessible
486 * through std routines)
487 */
mqueue_read_file(struct file * filp,char __user * u_data,size_t count,loff_t * off)488 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
489 size_t count, loff_t *off)
490 {
491 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
492 char buffer[FILENT_SIZE];
493 ssize_t ret;
494
495 spin_lock(&info->lock);
496 snprintf(buffer, sizeof(buffer),
497 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
498 info->qsize,
499 info->notify_owner ? info->notify.sigev_notify : 0,
500 (info->notify_owner &&
501 info->notify.sigev_notify == SIGEV_SIGNAL) ?
502 info->notify.sigev_signo : 0,
503 pid_vnr(info->notify_owner));
504 spin_unlock(&info->lock);
505 buffer[sizeof(buffer)-1] = '\0';
506
507 ret = simple_read_from_buffer(u_data, count, off, buffer,
508 strlen(buffer));
509 if (ret <= 0)
510 return ret;
511
512 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = CURRENT_TIME;
513 return ret;
514 }
515
mqueue_flush_file(struct file * filp,fl_owner_t id)516 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
517 {
518 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
519
520 spin_lock(&info->lock);
521 if (task_tgid(current) == info->notify_owner)
522 remove_notification(info);
523
524 spin_unlock(&info->lock);
525 return 0;
526 }
527
mqueue_poll_file(struct file * filp,struct poll_table_struct * poll_tab)528 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
529 {
530 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
531 int retval = 0;
532
533 poll_wait(filp, &info->wait_q, poll_tab);
534
535 spin_lock(&info->lock);
536 if (info->attr.mq_curmsgs)
537 retval = POLLIN | POLLRDNORM;
538
539 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
540 retval |= POLLOUT | POLLWRNORM;
541 spin_unlock(&info->lock);
542
543 return retval;
544 }
545
546 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
wq_add(struct mqueue_inode_info * info,int sr,struct ext_wait_queue * ewp)547 static void wq_add(struct mqueue_inode_info *info, int sr,
548 struct ext_wait_queue *ewp)
549 {
550 struct ext_wait_queue *walk;
551
552 ewp->task = current;
553
554 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
555 if (walk->task->static_prio <= current->static_prio) {
556 list_add_tail(&ewp->list, &walk->list);
557 return;
558 }
559 }
560 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
561 }
562
563 /*
564 * Puts current task to sleep. Caller must hold queue lock. After return
565 * lock isn't held.
566 * sr: SEND or RECV
567 */
wq_sleep(struct mqueue_inode_info * info,int sr,ktime_t * timeout,struct ext_wait_queue * ewp)568 static int wq_sleep(struct mqueue_inode_info *info, int sr,
569 ktime_t *timeout, struct ext_wait_queue *ewp)
570 {
571 int retval;
572 signed long time;
573
574 wq_add(info, sr, ewp);
575
576 for (;;) {
577 __set_current_state(TASK_INTERRUPTIBLE);
578
579 spin_unlock(&info->lock);
580 time = schedule_hrtimeout_range_clock(timeout, 0,
581 HRTIMER_MODE_ABS, CLOCK_REALTIME);
582
583 if (ewp->state == STATE_READY) {
584 retval = 0;
585 goto out;
586 }
587 spin_lock(&info->lock);
588 if (ewp->state == STATE_READY) {
589 retval = 0;
590 goto out_unlock;
591 }
592 if (signal_pending(current)) {
593 retval = -ERESTARTSYS;
594 break;
595 }
596 if (time == 0) {
597 retval = -ETIMEDOUT;
598 break;
599 }
600 }
601 list_del(&ewp->list);
602 out_unlock:
603 spin_unlock(&info->lock);
604 out:
605 return retval;
606 }
607
608 /*
609 * Returns waiting task that should be serviced first or NULL if none exists
610 */
wq_get_first_waiter(struct mqueue_inode_info * info,int sr)611 static struct ext_wait_queue *wq_get_first_waiter(
612 struct mqueue_inode_info *info, int sr)
613 {
614 struct list_head *ptr;
615
616 ptr = info->e_wait_q[sr].list.prev;
617 if (ptr == &info->e_wait_q[sr].list)
618 return NULL;
619 return list_entry(ptr, struct ext_wait_queue, list);
620 }
621
622
set_cookie(struct sk_buff * skb,char code)623 static inline void set_cookie(struct sk_buff *skb, char code)
624 {
625 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
626 }
627
628 /*
629 * The next function is only to split too long sys_mq_timedsend
630 */
__do_notify(struct mqueue_inode_info * info)631 static void __do_notify(struct mqueue_inode_info *info)
632 {
633 /* notification
634 * invoked when there is registered process and there isn't process
635 * waiting synchronously for message AND state of queue changed from
636 * empty to not empty. Here we are sure that no one is waiting
637 * synchronously. */
638 if (info->notify_owner &&
639 info->attr.mq_curmsgs == 1) {
640 struct siginfo sig_i;
641 switch (info->notify.sigev_notify) {
642 case SIGEV_NONE:
643 break;
644 case SIGEV_SIGNAL:
645 /* sends signal */
646
647 sig_i.si_signo = info->notify.sigev_signo;
648 sig_i.si_errno = 0;
649 sig_i.si_code = SI_MESGQ;
650 sig_i.si_value = info->notify.sigev_value;
651 /* map current pid/uid into info->owner's namespaces */
652 rcu_read_lock();
653 sig_i.si_pid = task_tgid_nr_ns(current,
654 ns_of_pid(info->notify_owner));
655 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
656 rcu_read_unlock();
657
658 kill_pid_info(info->notify.sigev_signo,
659 &sig_i, info->notify_owner);
660 break;
661 case SIGEV_THREAD:
662 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
663 netlink_sendskb(info->notify_sock, info->notify_cookie);
664 break;
665 }
666 /* after notification unregisters process */
667 put_pid(info->notify_owner);
668 put_user_ns(info->notify_user_ns);
669 info->notify_owner = NULL;
670 info->notify_user_ns = NULL;
671 }
672 wake_up(&info->wait_q);
673 }
674
prepare_timeout(const struct timespec __user * u_abs_timeout,ktime_t * expires,struct timespec * ts)675 static int prepare_timeout(const struct timespec __user *u_abs_timeout,
676 ktime_t *expires, struct timespec *ts)
677 {
678 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
679 return -EFAULT;
680 if (!timespec_valid(ts))
681 return -EINVAL;
682
683 *expires = timespec_to_ktime(*ts);
684 return 0;
685 }
686
remove_notification(struct mqueue_inode_info * info)687 static void remove_notification(struct mqueue_inode_info *info)
688 {
689 if (info->notify_owner != NULL &&
690 info->notify.sigev_notify == SIGEV_THREAD) {
691 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
692 netlink_sendskb(info->notify_sock, info->notify_cookie);
693 }
694 put_pid(info->notify_owner);
695 put_user_ns(info->notify_user_ns);
696 info->notify_owner = NULL;
697 info->notify_user_ns = NULL;
698 }
699
mq_attr_ok(struct ipc_namespace * ipc_ns,struct mq_attr * attr)700 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
701 {
702 int mq_treesize;
703 unsigned long total_size;
704
705 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
706 return -EINVAL;
707 if (capable(CAP_SYS_RESOURCE)) {
708 if (attr->mq_maxmsg > HARD_MSGMAX ||
709 attr->mq_msgsize > HARD_MSGSIZEMAX)
710 return -EINVAL;
711 } else {
712 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
713 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
714 return -EINVAL;
715 }
716 /* check for overflow */
717 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
718 return -EOVERFLOW;
719 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
720 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
721 sizeof(struct posix_msg_tree_node);
722 total_size = attr->mq_maxmsg * attr->mq_msgsize;
723 if (total_size + mq_treesize < total_size)
724 return -EOVERFLOW;
725 return 0;
726 }
727
728 /*
729 * Invoked when creating a new queue via sys_mq_open
730 */
do_create(struct ipc_namespace * ipc_ns,struct inode * dir,struct path * path,int oflag,umode_t mode,struct mq_attr * attr)731 static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
732 struct path *path, int oflag, umode_t mode,
733 struct mq_attr *attr)
734 {
735 const struct cred *cred = current_cred();
736 int ret;
737
738 if (attr) {
739 ret = mq_attr_ok(ipc_ns, attr);
740 if (ret)
741 return ERR_PTR(ret);
742 /* store for use during create */
743 path->dentry->d_fsdata = attr;
744 } else {
745 struct mq_attr def_attr;
746
747 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
748 ipc_ns->mq_msg_default);
749 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
750 ipc_ns->mq_msgsize_default);
751 ret = mq_attr_ok(ipc_ns, &def_attr);
752 if (ret)
753 return ERR_PTR(ret);
754 }
755
756 mode &= ~current_umask();
757 ret = vfs_create2(path->mnt, dir, path->dentry, mode, true);
758 path->dentry->d_fsdata = NULL;
759 if (ret)
760 return ERR_PTR(ret);
761 return dentry_open(path, oflag, cred);
762 }
763
764 /* Opens existing queue */
do_open(struct path * path,int oflag)765 static struct file *do_open(struct path *path, int oflag)
766 {
767 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
768 MAY_READ | MAY_WRITE };
769 int acc;
770 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
771 return ERR_PTR(-EINVAL);
772 acc = oflag2acc[oflag & O_ACCMODE];
773 if (inode_permission2(path->mnt, d_inode(path->dentry), acc))
774 return ERR_PTR(-EACCES);
775 return dentry_open(path, oflag, current_cred());
776 }
777
SYSCALL_DEFINE4(mq_open,const char __user *,u_name,int,oflag,umode_t,mode,struct mq_attr __user *,u_attr)778 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
779 struct mq_attr __user *, u_attr)
780 {
781 struct path path;
782 struct file *filp;
783 struct filename *name;
784 struct mq_attr attr;
785 int fd, error;
786 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
787 struct vfsmount *mnt = ipc_ns->mq_mnt;
788 struct dentry *root = mnt->mnt_root;
789 int ro;
790
791 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
792 return -EFAULT;
793
794 audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
795
796 if (IS_ERR(name = getname(u_name)))
797 return PTR_ERR(name);
798
799 fd = get_unused_fd_flags(O_CLOEXEC);
800 if (fd < 0)
801 goto out_putname;
802
803 ro = mnt_want_write(mnt); /* we'll drop it in any case */
804 error = 0;
805 mutex_lock(&d_inode(root)->i_mutex);
806 path.dentry = lookup_one_len2(name->name, mnt, root, strlen(name->name));
807 if (IS_ERR(path.dentry)) {
808 error = PTR_ERR(path.dentry);
809 goto out_putfd;
810 }
811 path.mnt = mntget(mnt);
812
813 if (oflag & O_CREAT) {
814 if (d_really_is_positive(path.dentry)) { /* entry already exists */
815 audit_inode(name, path.dentry, 0);
816 if (oflag & O_EXCL) {
817 error = -EEXIST;
818 goto out;
819 }
820 filp = do_open(&path, oflag);
821 } else {
822 if (ro) {
823 error = ro;
824 goto out;
825 }
826 audit_inode_parent_hidden(name, root);
827 filp = do_create(ipc_ns, d_inode(root),
828 &path, oflag, mode,
829 u_attr ? &attr : NULL);
830 }
831 } else {
832 if (d_really_is_negative(path.dentry)) {
833 error = -ENOENT;
834 goto out;
835 }
836 audit_inode(name, path.dentry, 0);
837 filp = do_open(&path, oflag);
838 }
839
840 if (!IS_ERR(filp))
841 fd_install(fd, filp);
842 else
843 error = PTR_ERR(filp);
844 out:
845 path_put(&path);
846 out_putfd:
847 if (error) {
848 put_unused_fd(fd);
849 fd = error;
850 }
851 mutex_unlock(&d_inode(root)->i_mutex);
852 if (!ro)
853 mnt_drop_write(mnt);
854 out_putname:
855 putname(name);
856 return fd;
857 }
858
SYSCALL_DEFINE1(mq_unlink,const char __user *,u_name)859 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
860 {
861 int err;
862 struct filename *name;
863 struct dentry *dentry;
864 struct inode *inode = NULL;
865 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
866 struct vfsmount *mnt = ipc_ns->mq_mnt;
867
868 name = getname(u_name);
869 if (IS_ERR(name))
870 return PTR_ERR(name);
871
872 audit_inode_parent_hidden(name, mnt->mnt_root);
873 err = mnt_want_write(mnt);
874 if (err)
875 goto out_name;
876 mutex_lock_nested(&d_inode(mnt->mnt_root)->i_mutex, I_MUTEX_PARENT);
877 dentry = lookup_one_len2(name->name, mnt, mnt->mnt_root,
878 strlen(name->name));
879 if (IS_ERR(dentry)) {
880 err = PTR_ERR(dentry);
881 goto out_unlock;
882 }
883
884 inode = d_inode(dentry);
885 if (!inode) {
886 err = -ENOENT;
887 } else {
888 ihold(inode);
889 err = vfs_unlink2(mnt, d_inode(dentry->d_parent), dentry, NULL);
890 }
891 dput(dentry);
892
893 out_unlock:
894 mutex_unlock(&d_inode(mnt->mnt_root)->i_mutex);
895 if (inode)
896 iput(inode);
897 mnt_drop_write(mnt);
898 out_name:
899 putname(name);
900
901 return err;
902 }
903
904 /* Pipelined send and receive functions.
905 *
906 * If a receiver finds no waiting message, then it registers itself in the
907 * list of waiting receivers. A sender checks that list before adding the new
908 * message into the message array. If there is a waiting receiver, then it
909 * bypasses the message array and directly hands the message over to the
910 * receiver. The receiver accepts the message and returns without grabbing the
911 * queue spinlock:
912 *
913 * - Set pointer to message.
914 * - Queue the receiver task for later wakeup (without the info->lock).
915 * - Update its state to STATE_READY. Now the receiver can continue.
916 * - Wake up the process after the lock is dropped. Should the process wake up
917 * before this wakeup (due to a timeout or a signal) it will either see
918 * STATE_READY and continue or acquire the lock to check the state again.
919 *
920 * The same algorithm is used for senders.
921 */
922
923 /* pipelined_send() - send a message directly to the task waiting in
924 * sys_mq_timedreceive() (without inserting message into a queue).
925 */
pipelined_send(struct wake_q_head * wake_q,struct mqueue_inode_info * info,struct msg_msg * message,struct ext_wait_queue * receiver)926 static inline void pipelined_send(struct wake_q_head *wake_q,
927 struct mqueue_inode_info *info,
928 struct msg_msg *message,
929 struct ext_wait_queue *receiver)
930 {
931 receiver->msg = message;
932 list_del(&receiver->list);
933 wake_q_add(wake_q, receiver->task);
934 /*
935 * Rely on the implicit cmpxchg barrier from wake_q_add such
936 * that we can ensure that updating receiver->state is the last
937 * write operation: As once set, the receiver can continue,
938 * and if we don't have the reference count from the wake_q,
939 * yet, at that point we can later have a use-after-free
940 * condition and bogus wakeup.
941 */
942 receiver->state = STATE_READY;
943 }
944
945 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
946 * gets its message and put to the queue (we have one free place for sure). */
pipelined_receive(struct wake_q_head * wake_q,struct mqueue_inode_info * info)947 static inline void pipelined_receive(struct wake_q_head *wake_q,
948 struct mqueue_inode_info *info)
949 {
950 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
951
952 if (!sender) {
953 /* for poll */
954 wake_up_interruptible(&info->wait_q);
955 return;
956 }
957 if (msg_insert(sender->msg, info))
958 return;
959
960 list_del(&sender->list);
961 wake_q_add(wake_q, sender->task);
962 sender->state = STATE_READY;
963 }
964
SYSCALL_DEFINE5(mq_timedsend,mqd_t,mqdes,const char __user *,u_msg_ptr,size_t,msg_len,unsigned int,msg_prio,const struct timespec __user *,u_abs_timeout)965 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
966 size_t, msg_len, unsigned int, msg_prio,
967 const struct timespec __user *, u_abs_timeout)
968 {
969 struct fd f;
970 struct inode *inode;
971 struct ext_wait_queue wait;
972 struct ext_wait_queue *receiver;
973 struct msg_msg *msg_ptr;
974 struct mqueue_inode_info *info;
975 ktime_t expires, *timeout = NULL;
976 struct timespec ts;
977 struct posix_msg_tree_node *new_leaf = NULL;
978 int ret = 0;
979 WAKE_Q(wake_q);
980
981 if (u_abs_timeout) {
982 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
983 if (res)
984 return res;
985 timeout = &expires;
986 }
987
988 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
989 return -EINVAL;
990
991 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
992
993 f = fdget(mqdes);
994 if (unlikely(!f.file)) {
995 ret = -EBADF;
996 goto out;
997 }
998
999 inode = file_inode(f.file);
1000 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1001 ret = -EBADF;
1002 goto out_fput;
1003 }
1004 info = MQUEUE_I(inode);
1005 audit_file(f.file);
1006
1007 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
1008 ret = -EBADF;
1009 goto out_fput;
1010 }
1011
1012 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1013 ret = -EMSGSIZE;
1014 goto out_fput;
1015 }
1016
1017 /* First try to allocate memory, before doing anything with
1018 * existing queues. */
1019 msg_ptr = load_msg(u_msg_ptr, msg_len);
1020 if (IS_ERR(msg_ptr)) {
1021 ret = PTR_ERR(msg_ptr);
1022 goto out_fput;
1023 }
1024 msg_ptr->m_ts = msg_len;
1025 msg_ptr->m_type = msg_prio;
1026
1027 /*
1028 * msg_insert really wants us to have a valid, spare node struct so
1029 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1030 * fall back to that if necessary.
1031 */
1032 if (!info->node_cache)
1033 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1034
1035 spin_lock(&info->lock);
1036
1037 if (!info->node_cache && new_leaf) {
1038 /* Save our speculative allocation into the cache */
1039 INIT_LIST_HEAD(&new_leaf->msg_list);
1040 info->node_cache = new_leaf;
1041 new_leaf = NULL;
1042 } else {
1043 kfree(new_leaf);
1044 }
1045
1046 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1047 if (f.file->f_flags & O_NONBLOCK) {
1048 ret = -EAGAIN;
1049 } else {
1050 wait.task = current;
1051 wait.msg = (void *) msg_ptr;
1052 wait.state = STATE_NONE;
1053 ret = wq_sleep(info, SEND, timeout, &wait);
1054 /*
1055 * wq_sleep must be called with info->lock held, and
1056 * returns with the lock released
1057 */
1058 goto out_free;
1059 }
1060 } else {
1061 receiver = wq_get_first_waiter(info, RECV);
1062 if (receiver) {
1063 pipelined_send(&wake_q, info, msg_ptr, receiver);
1064 } else {
1065 /* adds message to the queue */
1066 ret = msg_insert(msg_ptr, info);
1067 if (ret)
1068 goto out_unlock;
1069 __do_notify(info);
1070 }
1071 inode->i_atime = inode->i_mtime = inode->i_ctime =
1072 CURRENT_TIME;
1073 }
1074 out_unlock:
1075 spin_unlock(&info->lock);
1076 wake_up_q(&wake_q);
1077 out_free:
1078 if (ret)
1079 free_msg(msg_ptr);
1080 out_fput:
1081 fdput(f);
1082 out:
1083 return ret;
1084 }
1085
SYSCALL_DEFINE5(mq_timedreceive,mqd_t,mqdes,char __user *,u_msg_ptr,size_t,msg_len,unsigned int __user *,u_msg_prio,const struct timespec __user *,u_abs_timeout)1086 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1087 size_t, msg_len, unsigned int __user *, u_msg_prio,
1088 const struct timespec __user *, u_abs_timeout)
1089 {
1090 ssize_t ret;
1091 struct msg_msg *msg_ptr;
1092 struct fd f;
1093 struct inode *inode;
1094 struct mqueue_inode_info *info;
1095 struct ext_wait_queue wait;
1096 ktime_t expires, *timeout = NULL;
1097 struct timespec ts;
1098 struct posix_msg_tree_node *new_leaf = NULL;
1099
1100 if (u_abs_timeout) {
1101 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1102 if (res)
1103 return res;
1104 timeout = &expires;
1105 }
1106
1107 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1108
1109 f = fdget(mqdes);
1110 if (unlikely(!f.file)) {
1111 ret = -EBADF;
1112 goto out;
1113 }
1114
1115 inode = file_inode(f.file);
1116 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1117 ret = -EBADF;
1118 goto out_fput;
1119 }
1120 info = MQUEUE_I(inode);
1121 audit_file(f.file);
1122
1123 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1124 ret = -EBADF;
1125 goto out_fput;
1126 }
1127
1128 /* checks if buffer is big enough */
1129 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1130 ret = -EMSGSIZE;
1131 goto out_fput;
1132 }
1133
1134 /*
1135 * msg_insert really wants us to have a valid, spare node struct so
1136 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1137 * fall back to that if necessary.
1138 */
1139 if (!info->node_cache)
1140 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1141
1142 spin_lock(&info->lock);
1143
1144 if (!info->node_cache && new_leaf) {
1145 /* Save our speculative allocation into the cache */
1146 INIT_LIST_HEAD(&new_leaf->msg_list);
1147 info->node_cache = new_leaf;
1148 } else {
1149 kfree(new_leaf);
1150 }
1151
1152 if (info->attr.mq_curmsgs == 0) {
1153 if (f.file->f_flags & O_NONBLOCK) {
1154 spin_unlock(&info->lock);
1155 ret = -EAGAIN;
1156 } else {
1157 wait.task = current;
1158 wait.state = STATE_NONE;
1159 ret = wq_sleep(info, RECV, timeout, &wait);
1160 msg_ptr = wait.msg;
1161 }
1162 } else {
1163 WAKE_Q(wake_q);
1164
1165 msg_ptr = msg_get(info);
1166
1167 inode->i_atime = inode->i_mtime = inode->i_ctime =
1168 CURRENT_TIME;
1169
1170 /* There is now free space in queue. */
1171 pipelined_receive(&wake_q, info);
1172 spin_unlock(&info->lock);
1173 wake_up_q(&wake_q);
1174 ret = 0;
1175 }
1176 if (ret == 0) {
1177 ret = msg_ptr->m_ts;
1178
1179 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1180 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1181 ret = -EFAULT;
1182 }
1183 free_msg(msg_ptr);
1184 }
1185 out_fput:
1186 fdput(f);
1187 out:
1188 return ret;
1189 }
1190
1191 /*
1192 * Notes: the case when user wants us to deregister (with NULL as pointer)
1193 * and he isn't currently owner of notification, will be silently discarded.
1194 * It isn't explicitly defined in the POSIX.
1195 */
SYSCALL_DEFINE2(mq_notify,mqd_t,mqdes,const struct sigevent __user *,u_notification)1196 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1197 const struct sigevent __user *, u_notification)
1198 {
1199 int ret;
1200 struct fd f;
1201 struct sock *sock;
1202 struct inode *inode;
1203 struct sigevent notification;
1204 struct mqueue_inode_info *info;
1205 struct sk_buff *nc;
1206
1207 if (u_notification) {
1208 if (copy_from_user(¬ification, u_notification,
1209 sizeof(struct sigevent)))
1210 return -EFAULT;
1211 }
1212
1213 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL);
1214
1215 nc = NULL;
1216 sock = NULL;
1217 if (u_notification != NULL) {
1218 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1219 notification.sigev_notify != SIGEV_SIGNAL &&
1220 notification.sigev_notify != SIGEV_THREAD))
1221 return -EINVAL;
1222 if (notification.sigev_notify == SIGEV_SIGNAL &&
1223 !valid_signal(notification.sigev_signo)) {
1224 return -EINVAL;
1225 }
1226 if (notification.sigev_notify == SIGEV_THREAD) {
1227 long timeo;
1228
1229 /* create the notify skb */
1230 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1231 if (!nc) {
1232 ret = -ENOMEM;
1233 goto out;
1234 }
1235 if (copy_from_user(nc->data,
1236 notification.sigev_value.sival_ptr,
1237 NOTIFY_COOKIE_LEN)) {
1238 ret = -EFAULT;
1239 goto out;
1240 }
1241
1242 /* TODO: add a header? */
1243 skb_put(nc, NOTIFY_COOKIE_LEN);
1244 /* and attach it to the socket */
1245 retry:
1246 f = fdget(notification.sigev_signo);
1247 if (!f.file) {
1248 ret = -EBADF;
1249 goto out;
1250 }
1251 sock = netlink_getsockbyfilp(f.file);
1252 fdput(f);
1253 if (IS_ERR(sock)) {
1254 ret = PTR_ERR(sock);
1255 sock = NULL;
1256 goto out;
1257 }
1258
1259 timeo = MAX_SCHEDULE_TIMEOUT;
1260 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1261 if (ret == 1) {
1262 sock = NULL;
1263 goto retry;
1264 }
1265 if (ret) {
1266 sock = NULL;
1267 nc = NULL;
1268 goto out;
1269 }
1270 }
1271 }
1272
1273 f = fdget(mqdes);
1274 if (!f.file) {
1275 ret = -EBADF;
1276 goto out;
1277 }
1278
1279 inode = file_inode(f.file);
1280 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1281 ret = -EBADF;
1282 goto out_fput;
1283 }
1284 info = MQUEUE_I(inode);
1285
1286 ret = 0;
1287 spin_lock(&info->lock);
1288 if (u_notification == NULL) {
1289 if (info->notify_owner == task_tgid(current)) {
1290 remove_notification(info);
1291 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1292 }
1293 } else if (info->notify_owner != NULL) {
1294 ret = -EBUSY;
1295 } else {
1296 switch (notification.sigev_notify) {
1297 case SIGEV_NONE:
1298 info->notify.sigev_notify = SIGEV_NONE;
1299 break;
1300 case SIGEV_THREAD:
1301 info->notify_sock = sock;
1302 info->notify_cookie = nc;
1303 sock = NULL;
1304 nc = NULL;
1305 info->notify.sigev_notify = SIGEV_THREAD;
1306 break;
1307 case SIGEV_SIGNAL:
1308 info->notify.sigev_signo = notification.sigev_signo;
1309 info->notify.sigev_value = notification.sigev_value;
1310 info->notify.sigev_notify = SIGEV_SIGNAL;
1311 break;
1312 }
1313
1314 info->notify_owner = get_pid(task_tgid(current));
1315 info->notify_user_ns = get_user_ns(current_user_ns());
1316 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1317 }
1318 spin_unlock(&info->lock);
1319 out_fput:
1320 fdput(f);
1321 out:
1322 if (sock)
1323 netlink_detachskb(sock, nc);
1324 else if (nc)
1325 dev_kfree_skb(nc);
1326
1327 return ret;
1328 }
1329
SYSCALL_DEFINE3(mq_getsetattr,mqd_t,mqdes,const struct mq_attr __user *,u_mqstat,struct mq_attr __user *,u_omqstat)1330 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1331 const struct mq_attr __user *, u_mqstat,
1332 struct mq_attr __user *, u_omqstat)
1333 {
1334 int ret;
1335 struct mq_attr mqstat, omqstat;
1336 struct fd f;
1337 struct inode *inode;
1338 struct mqueue_inode_info *info;
1339
1340 if (u_mqstat != NULL) {
1341 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1342 return -EFAULT;
1343 if (mqstat.mq_flags & (~O_NONBLOCK))
1344 return -EINVAL;
1345 }
1346
1347 f = fdget(mqdes);
1348 if (!f.file) {
1349 ret = -EBADF;
1350 goto out;
1351 }
1352
1353 inode = file_inode(f.file);
1354 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1355 ret = -EBADF;
1356 goto out_fput;
1357 }
1358 info = MQUEUE_I(inode);
1359
1360 spin_lock(&info->lock);
1361
1362 omqstat = info->attr;
1363 omqstat.mq_flags = f.file->f_flags & O_NONBLOCK;
1364 if (u_mqstat) {
1365 audit_mq_getsetattr(mqdes, &mqstat);
1366 spin_lock(&f.file->f_lock);
1367 if (mqstat.mq_flags & O_NONBLOCK)
1368 f.file->f_flags |= O_NONBLOCK;
1369 else
1370 f.file->f_flags &= ~O_NONBLOCK;
1371 spin_unlock(&f.file->f_lock);
1372
1373 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1374 }
1375
1376 spin_unlock(&info->lock);
1377
1378 ret = 0;
1379 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1380 sizeof(struct mq_attr)))
1381 ret = -EFAULT;
1382
1383 out_fput:
1384 fdput(f);
1385 out:
1386 return ret;
1387 }
1388
1389 static const struct inode_operations mqueue_dir_inode_operations = {
1390 .lookup = simple_lookup,
1391 .create = mqueue_create,
1392 .unlink = mqueue_unlink,
1393 };
1394
1395 static const struct file_operations mqueue_file_operations = {
1396 .flush = mqueue_flush_file,
1397 .poll = mqueue_poll_file,
1398 .read = mqueue_read_file,
1399 .llseek = default_llseek,
1400 };
1401
1402 static const struct super_operations mqueue_super_ops = {
1403 .alloc_inode = mqueue_alloc_inode,
1404 .destroy_inode = mqueue_destroy_inode,
1405 .evict_inode = mqueue_evict_inode,
1406 .statfs = simple_statfs,
1407 };
1408
1409 static struct file_system_type mqueue_fs_type = {
1410 .name = "mqueue",
1411 .mount = mqueue_mount,
1412 .kill_sb = kill_litter_super,
1413 .fs_flags = FS_USERNS_MOUNT,
1414 };
1415
mq_init_ns(struct ipc_namespace * ns)1416 int mq_init_ns(struct ipc_namespace *ns)
1417 {
1418 ns->mq_queues_count = 0;
1419 ns->mq_queues_max = DFLT_QUEUESMAX;
1420 ns->mq_msg_max = DFLT_MSGMAX;
1421 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1422 ns->mq_msg_default = DFLT_MSG;
1423 ns->mq_msgsize_default = DFLT_MSGSIZE;
1424
1425 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1426 if (IS_ERR(ns->mq_mnt)) {
1427 int err = PTR_ERR(ns->mq_mnt);
1428 ns->mq_mnt = NULL;
1429 return err;
1430 }
1431 return 0;
1432 }
1433
mq_clear_sbinfo(struct ipc_namespace * ns)1434 void mq_clear_sbinfo(struct ipc_namespace *ns)
1435 {
1436 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1437 }
1438
mq_put_mnt(struct ipc_namespace * ns)1439 void mq_put_mnt(struct ipc_namespace *ns)
1440 {
1441 kern_unmount(ns->mq_mnt);
1442 }
1443
init_mqueue_fs(void)1444 static int __init init_mqueue_fs(void)
1445 {
1446 int error;
1447
1448 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1449 sizeof(struct mqueue_inode_info), 0,
1450 SLAB_HWCACHE_ALIGN, init_once);
1451 if (mqueue_inode_cachep == NULL)
1452 return -ENOMEM;
1453
1454 /* ignore failures - they are not fatal */
1455 mq_sysctl_table = mq_register_sysctl_table();
1456
1457 error = register_filesystem(&mqueue_fs_type);
1458 if (error)
1459 goto out_sysctl;
1460
1461 spin_lock_init(&mq_lock);
1462
1463 error = mq_init_ns(&init_ipc_ns);
1464 if (error)
1465 goto out_filesystem;
1466
1467 return 0;
1468
1469 out_filesystem:
1470 unregister_filesystem(&mqueue_fs_type);
1471 out_sysctl:
1472 if (mq_sysctl_table)
1473 unregister_sysctl_table(mq_sysctl_table);
1474 kmem_cache_destroy(mqueue_inode_cachep);
1475 return error;
1476 }
1477
1478 device_initcall(init_mqueue_fs);
1479