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TOMOYO Linux Cross Reference
Linux/ipc/mqueue.c

Version: ~ [ linux-5.5-rc7 ] ~ [ linux-5.4.13 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.97 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.166 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.210 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.210 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.81 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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 
 55 struct posix_msg_tree_node {
 56         struct rb_node          rb_node;
 57         struct list_head        msg_list;
 58         int                     priority;
 59 };
 60 
 61 struct 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 
 68 struct 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 
 90 static const struct inode_operations mqueue_dir_inode_operations;
 91 static const struct file_operations mqueue_file_operations;
 92 static const struct super_operations mqueue_super_ops;
 93 static void remove_notification(struct mqueue_inode_info *info);
 94 
 95 static struct kmem_cache *mqueue_inode_cachep;
 96 
 97 static struct ctl_table_header *mq_sysctl_table;
 98 
 99 static 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  */
107 static 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 
112 static 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 */
123 static 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);
152 insert_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 
159 static 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 
165 try_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 
215 static 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;
319 out_inode:
320         iput(inode);
321 err:
322         return ERR_PTR(ret);
323 }
324 
325 static 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 
346 static 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 
360 static 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 
367 static 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 
377 static 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 
383 static void mqueue_destroy_inode(struct inode *inode)
384 {
385         call_rcu(&inode->i_rcu, mqueue_i_callback);
386 }
387 
388 static 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 
436 static 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;
474 out_unlock:
475         spin_unlock(&mq_lock);
476         if (ipc_ns)
477                 put_ipc_ns(ipc_ns);
478         return error;
479 }
480 
481 static 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 
487 static 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 */
505 static 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 
533 static 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 
545 static __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 */
564 static 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  */
585 static 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);
620 out_unlock:
621         spin_unlock(&info->lock);
622 out:
623         return retval;
624 }
625 
626 /*
627  * Returns waiting task that should be serviced first or NULL if none exists
628  */
629 static 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 
641 static 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  */
649 static 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 kernel_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 
694 static int prepare_timeout(const struct __kernel_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 
704 static 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 
717 static 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 
744 static 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);
780 out_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);
788 out_putname:
789         putname(name);
790         return fd;
791 }
792 
793 SYSCALL_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 
803 SYSCALL_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 
837 out_unlock:
838         inode_unlock(d_inode(mnt->mnt_root));
839         if (inode)
840                 iput(inode);
841         mnt_drop_write(mnt);
842 out_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  */
870 static 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). */
891 static 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 
909 static 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         }
1015 out_unlock:
1016         spin_unlock(&info->lock);
1017         wake_up_q(&wake_q);
1018 out_free:
1019         if (ret)
1020                 free_msg(msg_ptr);
1021 out_fput:
1022         fdput(f);
1023 out:
1024         return ret;
1025 }
1026 
1027 static 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         }
1123 out_fput:
1124         fdput(f);
1125 out:
1126         return ret;
1127 }
1128 
1129 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1130                 size_t, msg_len, unsigned int, msg_prio,
1131                 const struct __kernel_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 
1143 SYSCALL_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 __kernel_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  */
1162 static 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 */
1203 retry:
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);
1277 out_fput:
1278         fdput(f);
1279 out:
1280         if (sock)
1281                 netlink_detachskb(sock, nc);
1282         else if (nc)
1283                 dev_kfree_skb(nc);
1284 
1285         return ret;
1286 }
1287 
1288 SYSCALL_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 
1300 static 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 
1344 SYSCALL_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 
1371 struct 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 
1379 static 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 
1395 static 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 
1410 COMPAT_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 
1423 COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1424                        const struct compat_sigevent __user *, u_notification)
1425 {
1426         struct sigevent n, *p = NULL;
1427         if (u_notification) {
1428                 if (get_compat_sigevent(&n, u_notification))
1429                         return -EFAULT;
1430                 if (n.sigev_notify == SIGEV_THREAD)
1431                         n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1432                 p = &n;
1433         }
1434         return do_mq_notify(mqdes, p);
1435 }
1436 
1437 COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1438                        const struct compat_mq_attr __user *, u_mqstat,
1439                        struct compat_mq_attr __user *, u_omqstat)
1440 {
1441         int ret;
1442         struct mq_attr mqstat, omqstat;
1443         struct mq_attr *new = NULL, *old = NULL;
1444 
1445         if (u_mqstat) {
1446                 new = &mqstat;
1447                 if (get_compat_mq_attr(new, u_mqstat))
1448                         return -EFAULT;
1449         }
1450         if (u_omqstat)
1451                 old = &omqstat;
1452 
1453         ret = do_mq_getsetattr(mqdes, new, old);
1454         if (ret || !old)
1455                 return ret;
1456 
1457         if (put_compat_mq_attr(old, u_omqstat))
1458                 return -EFAULT;
1459         return 0;
1460 }
1461 #endif
1462 
1463 #ifdef CONFIG_COMPAT_32BIT_TIME
1464 static int compat_prepare_timeout(const struct old_timespec32 __user *p,
1465                                    struct timespec64 *ts)
1466 {
1467         if (get_old_timespec32(ts, p))
1468                 return -EFAULT;
1469         if (!timespec64_valid(ts))
1470                 return -EINVAL;
1471         return 0;
1472 }
1473 
1474 COMPAT_SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes,
1475                        const char __user *, u_msg_ptr,
1476                        compat_size_t, msg_len, unsigned int, msg_prio,
1477                        const struct old_timespec32 __user *, u_abs_timeout)
1478 {
1479         struct timespec64 ts, *p = NULL;
1480         if (u_abs_timeout) {
1481                 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1482                 if (res)
1483                         return res;
1484                 p = &ts;
1485         }
1486         return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1487 }
1488 
1489 COMPAT_SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes,
1490                        char __user *, u_msg_ptr,
1491                        compat_size_t, msg_len, unsigned int __user *, u_msg_prio,
1492                        const struct old_timespec32 __user *, u_abs_timeout)
1493 {
1494         struct timespec64 ts, *p = NULL;
1495         if (u_abs_timeout) {
1496                 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1497                 if (res)
1498                         return res;
1499                 p = &ts;
1500         }
1501         return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1502 }
1503 #endif
1504 
1505 static const struct inode_operations mqueue_dir_inode_operations = {
1506         .lookup = simple_lookup,
1507         .create = mqueue_create,
1508         .unlink = mqueue_unlink,
1509 };
1510 
1511 static const struct file_operations mqueue_file_operations = {
1512         .flush = mqueue_flush_file,
1513         .poll = mqueue_poll_file,
1514         .read = mqueue_read_file,
1515         .llseek = default_llseek,
1516 };
1517 
1518 static const struct super_operations mqueue_super_ops = {
1519         .alloc_inode = mqueue_alloc_inode,
1520         .destroy_inode = mqueue_destroy_inode,
1521         .evict_inode = mqueue_evict_inode,
1522         .statfs = simple_statfs,
1523 };
1524 
1525 static struct file_system_type mqueue_fs_type = {
1526         .name = "mqueue",
1527         .mount = mqueue_mount,
1528         .kill_sb = kill_litter_super,
1529         .fs_flags = FS_USERNS_MOUNT,
1530 };
1531 
1532 int mq_init_ns(struct ipc_namespace *ns)
1533 {
1534         ns->mq_queues_count  = 0;
1535         ns->mq_queues_max    = DFLT_QUEUESMAX;
1536         ns->mq_msg_max       = DFLT_MSGMAX;
1537         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1538         ns->mq_msg_default   = DFLT_MSG;
1539         ns->mq_msgsize_default  = DFLT_MSGSIZE;
1540 
1541         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1542         if (IS_ERR(ns->mq_mnt)) {
1543                 int err = PTR_ERR(ns->mq_mnt);
1544                 ns->mq_mnt = NULL;
1545                 return err;
1546         }
1547         return 0;
1548 }
1549 
1550 void mq_clear_sbinfo(struct ipc_namespace *ns)
1551 {
1552         ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1553 }
1554 
1555 void mq_put_mnt(struct ipc_namespace *ns)
1556 {
1557         kern_unmount(ns->mq_mnt);
1558 }
1559 
1560 static int __init init_mqueue_fs(void)
1561 {
1562         int error;
1563 
1564         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1565                                 sizeof(struct mqueue_inode_info), 0,
1566                                 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1567         if (mqueue_inode_cachep == NULL)
1568                 return -ENOMEM;
1569 
1570         /* ignore failures - they are not fatal */
1571         mq_sysctl_table = mq_register_sysctl_table();
1572 
1573         error = register_filesystem(&mqueue_fs_type);
1574         if (error)
1575                 goto out_sysctl;
1576 
1577         spin_lock_init(&mq_lock);
1578 
1579         error = mq_init_ns(&init_ipc_ns);
1580         if (error)
1581                 goto out_filesystem;
1582 
1583         return 0;
1584 
1585 out_filesystem:
1586         unregister_filesystem(&mqueue_fs_type);
1587 out_sysctl:
1588         if (mq_sysctl_table)
1589                 unregister_sysctl_table(mq_sysctl_table);
1590         kmem_cache_destroy(mqueue_inode_cachep);
1591         return error;
1592 }
1593 
1594 device_initcall(init_mqueue_fs);
1595 

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