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1/*
2 * NET4: Implementation of BSD Unix domain sockets.
3 *
4 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * Fixes:
12 * Linus Torvalds : Assorted bug cures.
13 * Niibe Yutaka : async I/O support.
14 * Carsten Paeth : PF_UNIX check, address fixes.
15 * Alan Cox : Limit size of allocated blocks.
16 * Alan Cox : Fixed the stupid socketpair bug.
17 * Alan Cox : BSD compatibility fine tuning.
18 * Alan Cox : Fixed a bug in connect when interrupted.
19 * Alan Cox : Sorted out a proper draft version of
20 * file descriptor passing hacked up from
21 * Mike Shaver's work.
22 * Marty Leisner : Fixes to fd passing
23 * Nick Nevin : recvmsg bugfix.
24 * Alan Cox : Started proper garbage collector
25 * Heiko EiBfeldt : Missing verify_area check
26 * Alan Cox : Started POSIXisms
27 * Andreas Schwab : Replace inode by dentry for proper
28 * reference counting
29 * Kirk Petersen : Made this a module
30 * Christoph Rohland : Elegant non-blocking accept/connect algorithm.
31 * Lots of bug fixes.
32 * Alexey Kuznetosv : Repaired (I hope) bugs introduces
33 * by above two patches.
34 * Andrea Arcangeli : If possible we block in connect(2)
35 * if the max backlog of the listen socket
36 * is been reached. This won't break
37 * old apps and it will avoid huge amount
38 * of socks hashed (this for unix_gc()
39 * performances reasons).
40 * Security fix that limits the max
41 * number of socks to 2*max_files and
42 * the number of skb queueable in the
43 * dgram receiver.
44 * Artur Skawina : Hash function optimizations
45 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
46 * Malcolm Beattie : Set peercred for socketpair
47 * Michal Ostrowski : Module initialization cleanup.
48 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT,
49 * the core infrastructure is doing that
50 * for all net proto families now (2.5.69+)
51 *
52 *
53 * Known differences from reference BSD that was tested:
54 *
55 * [TO FIX]
56 * ECONNREFUSED is not returned from one end of a connected() socket to the
57 * other the moment one end closes.
58 * fstat() doesn't return st_dev=0, and give the blksize as high water mark
59 * and a fake inode identifier (nor the BSD first socket fstat twice bug).
60 * [NOT TO FIX]
61 * accept() returns a path name even if the connecting socket has closed
62 * in the meantime (BSD loses the path and gives up).
63 * accept() returns 0 length path for an unbound connector. BSD returns 16
64 * and a null first byte in the path (but not for gethost/peername - BSD bug ??)
65 * socketpair(...SOCK_RAW..) doesn't panic the kernel.
66 * BSD af_unix apparently has connect forgetting to block properly.
67 * (need to check this with the POSIX spec in detail)
68 *
69 * Differences from 2.0.0-11-... (ANK)
70 * Bug fixes and improvements.
71 * - client shutdown killed server socket.
72 * - removed all useless cli/sti pairs.
73 *
74 * Semantic changes/extensions.
75 * - generic control message passing.
76 * - SCM_CREDENTIALS control message.
77 * - "Abstract" (not FS based) socket bindings.
78 * Abstract names are sequences of bytes (not zero terminated)
79 * started by 0, so that this name space does not intersect
80 * with BSD names.
81 */
82
83#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
84
85#include <linux/module.h>
86#include <linux/kernel.h>
87#include <linux/signal.h>
88#include <linux/sched.h>
89#include <linux/errno.h>
90#include <linux/string.h>
91#include <linux/stat.h>
92#include <linux/dcache.h>
93#include <linux/namei.h>
94#include <linux/socket.h>
95#include <linux/un.h>
96#include <linux/fcntl.h>
97#include <linux/termios.h>
98#include <linux/sockios.h>
99#include <linux/net.h>
100#include <linux/in.h>
101#include <linux/fs.h>
102#include <linux/slab.h>
103#include <asm/uaccess.h>
104#include <linux/skbuff.h>
105#include <linux/netdevice.h>
106#include <net/net_namespace.h>
107#include <net/sock.h>
108#include <net/tcp_states.h>
109#include <net/af_unix.h>
110#include <linux/proc_fs.h>
111#include <linux/seq_file.h>
112#include <net/scm.h>
113#include <linux/init.h>
114#include <linux/poll.h>
115#include <linux/rtnetlink.h>
116#include <linux/mount.h>
117#include <net/checksum.h>
118#include <linux/security.h>
119#include <linux/freezer.h>
120
121struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
122EXPORT_SYMBOL_GPL(unix_socket_table);
123DEFINE_SPINLOCK(unix_table_lock);
124EXPORT_SYMBOL_GPL(unix_table_lock);
125static atomic_long_t unix_nr_socks;
126
127
128static struct hlist_head *unix_sockets_unbound(void *addr)
129{
130 unsigned long hash = (unsigned long)addr;
131
132 hash ^= hash >> 16;
133 hash ^= hash >> 8;
134 hash %= UNIX_HASH_SIZE;
135 return &unix_socket_table[UNIX_HASH_SIZE + hash];
136}
137
138#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
139
140#ifdef CONFIG_SECURITY_NETWORK
141static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
142{
143 UNIXCB(skb).secid = scm->secid;
144}
145
146static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
147{
148 scm->secid = UNIXCB(skb).secid;
149}
150
151static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
152{
153 return (scm->secid == UNIXCB(skb).secid);
154}
155#else
156static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
157{ }
158
159static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
160{ }
161
162static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
163{
164 return true;
165}
166#endif /* CONFIG_SECURITY_NETWORK */
167
168/*
169 * SMP locking strategy:
170 * hash table is protected with spinlock unix_table_lock
171 * each socket state is protected by separate spin lock.
172 */
173
174static inline unsigned int unix_hash_fold(__wsum n)
175{
176 unsigned int hash = (__force unsigned int)csum_fold(n);
177
178 hash ^= hash>>8;
179 return hash&(UNIX_HASH_SIZE-1);
180}
181
182#define unix_peer(sk) (unix_sk(sk)->peer)
183
184static inline int unix_our_peer(struct sock *sk, struct sock *osk)
185{
186 return unix_peer(osk) == sk;
187}
188
189static inline int unix_may_send(struct sock *sk, struct sock *osk)
190{
191 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
192}
193
194static inline int unix_recvq_full(struct sock const *sk)
195{
196 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
197}
198
199struct sock *unix_peer_get(struct sock *s)
200{
201 struct sock *peer;
202
203 unix_state_lock(s);
204 peer = unix_peer(s);
205 if (peer)
206 sock_hold(peer);
207 unix_state_unlock(s);
208 return peer;
209}
210EXPORT_SYMBOL_GPL(unix_peer_get);
211
212static inline void unix_release_addr(struct unix_address *addr)
213{
214 if (atomic_dec_and_test(&addr->refcnt))
215 kfree(addr);
216}
217
218/*
219 * Check unix socket name:
220 * - should be not zero length.
221 * - if started by not zero, should be NULL terminated (FS object)
222 * - if started by zero, it is abstract name.
223 */
224
225static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
226{
227 if (len <= sizeof(short) || len > sizeof(*sunaddr))
228 return -EINVAL;
229 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
230 return -EINVAL;
231 if (sunaddr->sun_path[0]) {
232 /*
233 * This may look like an off by one error but it is a bit more
234 * subtle. 108 is the longest valid AF_UNIX path for a binding.
235 * sun_path[108] doesn't as such exist. However in kernel space
236 * we are guaranteed that it is a valid memory location in our
237 * kernel address buffer.
238 */
239 ((char *)sunaddr)[len] = 0;
240 len = strlen(sunaddr->sun_path)+1+sizeof(short);
241 return len;
242 }
243
244 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
245 return len;
246}
247
248static void __unix_remove_socket(struct sock *sk)
249{
250 sk_del_node_init(sk);
251}
252
253static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
254{
255 WARN_ON(!sk_unhashed(sk));
256 sk_add_node(sk, list);
257}
258
259static inline void unix_remove_socket(struct sock *sk)
260{
261 spin_lock(&unix_table_lock);
262 __unix_remove_socket(sk);
263 spin_unlock(&unix_table_lock);
264}
265
266static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
267{
268 spin_lock(&unix_table_lock);
269 __unix_insert_socket(list, sk);
270 spin_unlock(&unix_table_lock);
271}
272
273static struct sock *__unix_find_socket_byname(struct net *net,
274 struct sockaddr_un *sunname,
275 int len, int type, unsigned int hash)
276{
277 struct sock *s;
278
279 sk_for_each(s, &unix_socket_table[hash ^ type]) {
280 struct unix_sock *u = unix_sk(s);
281
282 if (!net_eq(sock_net(s), net))
283 continue;
284
285 if (u->addr->len == len &&
286 !memcmp(u->addr->name, sunname, len))
287 goto found;
288 }
289 s = NULL;
290found:
291 return s;
292}
293
294static inline struct sock *unix_find_socket_byname(struct net *net,
295 struct sockaddr_un *sunname,
296 int len, int type,
297 unsigned int hash)
298{
299 struct sock *s;
300
301 spin_lock(&unix_table_lock);
302 s = __unix_find_socket_byname(net, sunname, len, type, hash);
303 if (s)
304 sock_hold(s);
305 spin_unlock(&unix_table_lock);
306 return s;
307}
308
309static struct sock *unix_find_socket_byinode(struct inode *i)
310{
311 struct sock *s;
312
313 spin_lock(&unix_table_lock);
314 sk_for_each(s,
315 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
316 struct dentry *dentry = unix_sk(s)->path.dentry;
317
318 if (dentry && d_backing_inode(dentry) == i) {
319 sock_hold(s);
320 goto found;
321 }
322 }
323 s = NULL;
324found:
325 spin_unlock(&unix_table_lock);
326 return s;
327}
328
329/* Support code for asymmetrically connected dgram sockets
330 *
331 * If a datagram socket is connected to a socket not itself connected
332 * to the first socket (eg, /dev/log), clients may only enqueue more
333 * messages if the present receive queue of the server socket is not
334 * "too large". This means there's a second writeability condition
335 * poll and sendmsg need to test. The dgram recv code will do a wake
336 * up on the peer_wait wait queue of a socket upon reception of a
337 * datagram which needs to be propagated to sleeping would-be writers
338 * since these might not have sent anything so far. This can't be
339 * accomplished via poll_wait because the lifetime of the server
340 * socket might be less than that of its clients if these break their
341 * association with it or if the server socket is closed while clients
342 * are still connected to it and there's no way to inform "a polling
343 * implementation" that it should let go of a certain wait queue
344 *
345 * In order to propagate a wake up, a wait_queue_t of the client
346 * socket is enqueued on the peer_wait queue of the server socket
347 * whose wake function does a wake_up on the ordinary client socket
348 * wait queue. This connection is established whenever a write (or
349 * poll for write) hit the flow control condition and broken when the
350 * association to the server socket is dissolved or after a wake up
351 * was relayed.
352 */
353
354static int unix_dgram_peer_wake_relay(wait_queue_t *q, unsigned mode, int flags,
355 void *key)
356{
357 struct unix_sock *u;
358 wait_queue_head_t *u_sleep;
359
360 u = container_of(q, struct unix_sock, peer_wake);
361
362 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
363 q);
364 u->peer_wake.private = NULL;
365
366 /* relaying can only happen while the wq still exists */
367 u_sleep = sk_sleep(&u->sk);
368 if (u_sleep)
369 wake_up_interruptible_poll(u_sleep, key);
370
371 return 0;
372}
373
374static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
375{
376 struct unix_sock *u, *u_other;
377 int rc;
378
379 u = unix_sk(sk);
380 u_other = unix_sk(other);
381 rc = 0;
382 spin_lock(&u_other->peer_wait.lock);
383
384 if (!u->peer_wake.private) {
385 u->peer_wake.private = other;
386 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
387
388 rc = 1;
389 }
390
391 spin_unlock(&u_other->peer_wait.lock);
392 return rc;
393}
394
395static void unix_dgram_peer_wake_disconnect(struct sock *sk,
396 struct sock *other)
397{
398 struct unix_sock *u, *u_other;
399
400 u = unix_sk(sk);
401 u_other = unix_sk(other);
402 spin_lock(&u_other->peer_wait.lock);
403
404 if (u->peer_wake.private == other) {
405 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
406 u->peer_wake.private = NULL;
407 }
408
409 spin_unlock(&u_other->peer_wait.lock);
410}
411
412static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
413 struct sock *other)
414{
415 unix_dgram_peer_wake_disconnect(sk, other);
416 wake_up_interruptible_poll(sk_sleep(sk),
417 POLLOUT |
418 POLLWRNORM |
419 POLLWRBAND);
420}
421
422/* preconditions:
423 * - unix_peer(sk) == other
424 * - association is stable
425 */
426static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
427{
428 int connected;
429
430 connected = unix_dgram_peer_wake_connect(sk, other);
431
432 if (unix_recvq_full(other))
433 return 1;
434
435 if (connected)
436 unix_dgram_peer_wake_disconnect(sk, other);
437
438 return 0;
439}
440
441static int unix_writable(const struct sock *sk)
442{
443 return sk->sk_state != TCP_LISTEN &&
444 (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
445}
446
447static void unix_write_space(struct sock *sk)
448{
449 struct socket_wq *wq;
450
451 rcu_read_lock();
452 if (unix_writable(sk)) {
453 wq = rcu_dereference(sk->sk_wq);
454 if (skwq_has_sleeper(wq))
455 wake_up_interruptible_sync_poll(&wq->wait,
456 POLLOUT | POLLWRNORM | POLLWRBAND);
457 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
458 }
459 rcu_read_unlock();
460}
461
462/* When dgram socket disconnects (or changes its peer), we clear its receive
463 * queue of packets arrived from previous peer. First, it allows to do
464 * flow control based only on wmem_alloc; second, sk connected to peer
465 * may receive messages only from that peer. */
466static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
467{
468 if (!skb_queue_empty(&sk->sk_receive_queue)) {
469 skb_queue_purge(&sk->sk_receive_queue);
470 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
471
472 /* If one link of bidirectional dgram pipe is disconnected,
473 * we signal error. Messages are lost. Do not make this,
474 * when peer was not connected to us.
475 */
476 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
477 other->sk_err = ECONNRESET;
478 other->sk_error_report(other);
479 }
480 }
481}
482
483static void unix_sock_destructor(struct sock *sk)
484{
485 struct unix_sock *u = unix_sk(sk);
486
487 skb_queue_purge(&sk->sk_receive_queue);
488
489 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
490 WARN_ON(!sk_unhashed(sk));
491 WARN_ON(sk->sk_socket);
492 if (!sock_flag(sk, SOCK_DEAD)) {
493 pr_info("Attempt to release alive unix socket: %p\n", sk);
494 return;
495 }
496
497 if (u->addr)
498 unix_release_addr(u->addr);
499
500 atomic_long_dec(&unix_nr_socks);
501 local_bh_disable();
502 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
503 local_bh_enable();
504#ifdef UNIX_REFCNT_DEBUG
505 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
506 atomic_long_read(&unix_nr_socks));
507#endif
508}
509
510static void unix_release_sock(struct sock *sk, int embrion)
511{
512 struct unix_sock *u = unix_sk(sk);
513 struct path path;
514 struct sock *skpair;
515 struct sk_buff *skb;
516 int state;
517
518 unix_remove_socket(sk);
519
520 /* Clear state */
521 unix_state_lock(sk);
522 sock_orphan(sk);
523 sk->sk_shutdown = SHUTDOWN_MASK;
524 path = u->path;
525 u->path.dentry = NULL;
526 u->path.mnt = NULL;
527 state = sk->sk_state;
528 sk->sk_state = TCP_CLOSE;
529 unix_state_unlock(sk);
530
531 wake_up_interruptible_all(&u->peer_wait);
532
533 skpair = unix_peer(sk);
534
535 if (skpair != NULL) {
536 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
537 unix_state_lock(skpair);
538 /* No more writes */
539 skpair->sk_shutdown = SHUTDOWN_MASK;
540 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
541 skpair->sk_err = ECONNRESET;
542 unix_state_unlock(skpair);
543 skpair->sk_state_change(skpair);
544 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
545 }
546
547 unix_dgram_peer_wake_disconnect(sk, skpair);
548 sock_put(skpair); /* It may now die */
549 unix_peer(sk) = NULL;
550 }
551
552 /* Try to flush out this socket. Throw out buffers at least */
553
554 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
555 if (state == TCP_LISTEN)
556 unix_release_sock(skb->sk, 1);
557 /* passed fds are erased in the kfree_skb hook */
558 UNIXCB(skb).consumed = skb->len;
559 kfree_skb(skb);
560 }
561
562 if (path.dentry)
563 path_put(&path);
564
565 sock_put(sk);
566
567 /* ---- Socket is dead now and most probably destroyed ---- */
568
569 /*
570 * Fixme: BSD difference: In BSD all sockets connected to us get
571 * ECONNRESET and we die on the spot. In Linux we behave
572 * like files and pipes do and wait for the last
573 * dereference.
574 *
575 * Can't we simply set sock->err?
576 *
577 * What the above comment does talk about? --ANK(980817)
578 */
579
580 if (unix_tot_inflight)
581 unix_gc(); /* Garbage collect fds */
582}
583
584static void init_peercred(struct sock *sk)
585{
586 put_pid(sk->sk_peer_pid);
587 if (sk->sk_peer_cred)
588 put_cred(sk->sk_peer_cred);
589 sk->sk_peer_pid = get_pid(task_tgid(current));
590 sk->sk_peer_cred = get_current_cred();
591}
592
593static void copy_peercred(struct sock *sk, struct sock *peersk)
594{
595 put_pid(sk->sk_peer_pid);
596 if (sk->sk_peer_cred)
597 put_cred(sk->sk_peer_cred);
598 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
599 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
600}
601
602static int unix_listen(struct socket *sock, int backlog)
603{
604 int err;
605 struct sock *sk = sock->sk;
606 struct unix_sock *u = unix_sk(sk);
607 struct pid *old_pid = NULL;
608
609 err = -EOPNOTSUPP;
610 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
611 goto out; /* Only stream/seqpacket sockets accept */
612 err = -EINVAL;
613 if (!u->addr)
614 goto out; /* No listens on an unbound socket */
615 unix_state_lock(sk);
616 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
617 goto out_unlock;
618 if (backlog > sk->sk_max_ack_backlog)
619 wake_up_interruptible_all(&u->peer_wait);
620 sk->sk_max_ack_backlog = backlog;
621 sk->sk_state = TCP_LISTEN;
622 /* set credentials so connect can copy them */
623 init_peercred(sk);
624 err = 0;
625
626out_unlock:
627 unix_state_unlock(sk);
628 put_pid(old_pid);
629out:
630 return err;
631}
632
633static int unix_release(struct socket *);
634static int unix_bind(struct socket *, struct sockaddr *, int);
635static int unix_stream_connect(struct socket *, struct sockaddr *,
636 int addr_len, int flags);
637static int unix_socketpair(struct socket *, struct socket *);
638static int unix_accept(struct socket *, struct socket *, int);
639static int unix_getname(struct socket *, struct sockaddr *, int *, int);
640static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
641static unsigned int unix_dgram_poll(struct file *, struct socket *,
642 poll_table *);
643static int unix_ioctl(struct socket *, unsigned int, unsigned long);
644static int unix_shutdown(struct socket *, int);
645static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
646static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
647static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
648 size_t size, int flags);
649static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
650 struct pipe_inode_info *, size_t size,
651 unsigned int flags);
652static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
653static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
654static int unix_dgram_connect(struct socket *, struct sockaddr *,
655 int, int);
656static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
657static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
658 int);
659
660static int unix_set_peek_off(struct sock *sk, int val)
661{
662 struct unix_sock *u = unix_sk(sk);
663
664 if (mutex_lock_interruptible(&u->readlock))
665 return -EINTR;
666
667 sk->sk_peek_off = val;
668 mutex_unlock(&u->readlock);
669
670 return 0;
671}
672
673
674static const struct proto_ops unix_stream_ops = {
675 .family = PF_UNIX,
676 .owner = THIS_MODULE,
677 .release = unix_release,
678 .bind = unix_bind,
679 .connect = unix_stream_connect,
680 .socketpair = unix_socketpair,
681 .accept = unix_accept,
682 .getname = unix_getname,
683 .poll = unix_poll,
684 .ioctl = unix_ioctl,
685 .listen = unix_listen,
686 .shutdown = unix_shutdown,
687 .setsockopt = sock_no_setsockopt,
688 .getsockopt = sock_no_getsockopt,
689 .sendmsg = unix_stream_sendmsg,
690 .recvmsg = unix_stream_recvmsg,
691 .mmap = sock_no_mmap,
692 .sendpage = unix_stream_sendpage,
693 .splice_read = unix_stream_splice_read,
694 .set_peek_off = unix_set_peek_off,
695};
696
697static const struct proto_ops unix_dgram_ops = {
698 .family = PF_UNIX,
699 .owner = THIS_MODULE,
700 .release = unix_release,
701 .bind = unix_bind,
702 .connect = unix_dgram_connect,
703 .socketpair = unix_socketpair,
704 .accept = sock_no_accept,
705 .getname = unix_getname,
706 .poll = unix_dgram_poll,
707 .ioctl = unix_ioctl,
708 .listen = sock_no_listen,
709 .shutdown = unix_shutdown,
710 .setsockopt = sock_no_setsockopt,
711 .getsockopt = sock_no_getsockopt,
712 .sendmsg = unix_dgram_sendmsg,
713 .recvmsg = unix_dgram_recvmsg,
714 .mmap = sock_no_mmap,
715 .sendpage = sock_no_sendpage,
716 .set_peek_off = unix_set_peek_off,
717};
718
719static const struct proto_ops unix_seqpacket_ops = {
720 .family = PF_UNIX,
721 .owner = THIS_MODULE,
722 .release = unix_release,
723 .bind = unix_bind,
724 .connect = unix_stream_connect,
725 .socketpair = unix_socketpair,
726 .accept = unix_accept,
727 .getname = unix_getname,
728 .poll = unix_dgram_poll,
729 .ioctl = unix_ioctl,
730 .listen = unix_listen,
731 .shutdown = unix_shutdown,
732 .setsockopt = sock_no_setsockopt,
733 .getsockopt = sock_no_getsockopt,
734 .sendmsg = unix_seqpacket_sendmsg,
735 .recvmsg = unix_seqpacket_recvmsg,
736 .mmap = sock_no_mmap,
737 .sendpage = sock_no_sendpage,
738 .set_peek_off = unix_set_peek_off,
739};
740
741static struct proto unix_proto = {
742 .name = "UNIX",
743 .owner = THIS_MODULE,
744 .obj_size = sizeof(struct unix_sock),
745};
746
747/*
748 * AF_UNIX sockets do not interact with hardware, hence they
749 * dont trigger interrupts - so it's safe for them to have
750 * bh-unsafe locking for their sk_receive_queue.lock. Split off
751 * this special lock-class by reinitializing the spinlock key:
752 */
753static struct lock_class_key af_unix_sk_receive_queue_lock_key;
754
755static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
756{
757 struct sock *sk = NULL;
758 struct unix_sock *u;
759
760 atomic_long_inc(&unix_nr_socks);
761 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
762 goto out;
763
764 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
765 if (!sk)
766 goto out;
767
768 sock_init_data(sock, sk);
769 lockdep_set_class(&sk->sk_receive_queue.lock,
770 &af_unix_sk_receive_queue_lock_key);
771
772 sk->sk_write_space = unix_write_space;
773 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
774 sk->sk_destruct = unix_sock_destructor;
775 u = unix_sk(sk);
776 u->path.dentry = NULL;
777 u->path.mnt = NULL;
778 spin_lock_init(&u->lock);
779 atomic_long_set(&u->inflight, 0);
780 INIT_LIST_HEAD(&u->link);
781 mutex_init(&u->readlock); /* single task reading lock */
782 init_waitqueue_head(&u->peer_wait);
783 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
784 unix_insert_socket(unix_sockets_unbound(sk), sk);
785out:
786 if (sk == NULL)
787 atomic_long_dec(&unix_nr_socks);
788 else {
789 local_bh_disable();
790 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
791 local_bh_enable();
792 }
793 return sk;
794}
795
796static int unix_create(struct net *net, struct socket *sock, int protocol,
797 int kern)
798{
799 if (protocol && protocol != PF_UNIX)
800 return -EPROTONOSUPPORT;
801
802 sock->state = SS_UNCONNECTED;
803
804 switch (sock->type) {
805 case SOCK_STREAM:
806 sock->ops = &unix_stream_ops;
807 break;
808 /*
809 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
810 * nothing uses it.
811 */
812 case SOCK_RAW:
813 sock->type = SOCK_DGRAM;
814 case SOCK_DGRAM:
815 sock->ops = &unix_dgram_ops;
816 break;
817 case SOCK_SEQPACKET:
818 sock->ops = &unix_seqpacket_ops;
819 break;
820 default:
821 return -ESOCKTNOSUPPORT;
822 }
823
824 return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
825}
826
827static int unix_release(struct socket *sock)
828{
829 struct sock *sk = sock->sk;
830
831 if (!sk)
832 return 0;
833
834 unix_release_sock(sk, 0);
835 sock->sk = NULL;
836
837 return 0;
838}
839
840static int unix_autobind(struct socket *sock)
841{
842 struct sock *sk = sock->sk;
843 struct net *net = sock_net(sk);
844 struct unix_sock *u = unix_sk(sk);
845 static u32 ordernum = 1;
846 struct unix_address *addr;
847 int err;
848 unsigned int retries = 0;
849
850 err = mutex_lock_interruptible(&u->readlock);
851 if (err)
852 return err;
853
854 err = 0;
855 if (u->addr)
856 goto out;
857
858 err = -ENOMEM;
859 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
860 if (!addr)
861 goto out;
862
863 addr->name->sun_family = AF_UNIX;
864 atomic_set(&addr->refcnt, 1);
865
866retry:
867 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
868 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
869
870 spin_lock(&unix_table_lock);
871 ordernum = (ordernum+1)&0xFFFFF;
872
873 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
874 addr->hash)) {
875 spin_unlock(&unix_table_lock);
876 /*
877 * __unix_find_socket_byname() may take long time if many names
878 * are already in use.
879 */
880 cond_resched();
881 /* Give up if all names seems to be in use. */
882 if (retries++ == 0xFFFFF) {
883 err = -ENOSPC;
884 kfree(addr);
885 goto out;
886 }
887 goto retry;
888 }
889 addr->hash ^= sk->sk_type;
890
891 __unix_remove_socket(sk);
892 u->addr = addr;
893 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
894 spin_unlock(&unix_table_lock);
895 err = 0;
896
897out: mutex_unlock(&u->readlock);
898 return err;
899}
900
901static struct sock *unix_find_other(struct net *net,
902 struct sockaddr_un *sunname, int len,
903 int type, unsigned int hash, int *error)
904{
905 struct sock *u;
906 struct path path;
907 int err = 0;
908
909 if (sunname->sun_path[0]) {
910 struct inode *inode;
911 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
912 if (err)
913 goto fail;
914 inode = d_backing_inode(path.dentry);
915 err = inode_permission(inode, MAY_WRITE);
916 if (err)
917 goto put_fail;
918
919 err = -ECONNREFUSED;
920 if (!S_ISSOCK(inode->i_mode))
921 goto put_fail;
922 u = unix_find_socket_byinode(inode);
923 if (!u)
924 goto put_fail;
925
926 if (u->sk_type == type)
927 touch_atime(&path);
928
929 path_put(&path);
930
931 err = -EPROTOTYPE;
932 if (u->sk_type != type) {
933 sock_put(u);
934 goto fail;
935 }
936 } else {
937 err = -ECONNREFUSED;
938 u = unix_find_socket_byname(net, sunname, len, type, hash);
939 if (u) {
940 struct dentry *dentry;
941 dentry = unix_sk(u)->path.dentry;
942 if (dentry)
943 touch_atime(&unix_sk(u)->path);
944 } else
945 goto fail;
946 }
947 return u;
948
949put_fail:
950 path_put(&path);
951fail:
952 *error = err;
953 return NULL;
954}
955
956static int unix_mknod(struct dentry *dentry, struct path *path, umode_t mode,
957 struct path *res)
958{
959 int err;
960
961 err = security_path_mknod(path, dentry, mode, 0);
962 if (!err) {
963 err = vfs_mknod(d_inode(path->dentry), dentry, mode, 0);
964 if (!err) {
965 res->mnt = mntget(path->mnt);
966 res->dentry = dget(dentry);
967 }
968 }
969
970 return err;
971}
972
973static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
974{
975 struct sock *sk = sock->sk;
976 struct net *net = sock_net(sk);
977 struct unix_sock *u = unix_sk(sk);
978 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
979 char *sun_path = sunaddr->sun_path;
980 int err, name_err;
981 unsigned int hash;
982 struct unix_address *addr;
983 struct hlist_head *list;
984 struct path path;
985 struct dentry *dentry;
986
987 err = -EINVAL;
988 if (sunaddr->sun_family != AF_UNIX)
989 goto out;
990
991 if (addr_len == sizeof(short)) {
992 err = unix_autobind(sock);
993 goto out;
994 }
995
996 err = unix_mkname(sunaddr, addr_len, &hash);
997 if (err < 0)
998 goto out;
999 addr_len = err;
1000
1001 name_err = 0;
1002 dentry = NULL;
1003 if (sun_path[0]) {
1004 /* Get the parent directory, calculate the hash for last
1005 * component.
1006 */
1007 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
1008
1009 if (IS_ERR(dentry)) {
1010 /* delay report until after 'already bound' check */
1011 name_err = PTR_ERR(dentry);
1012 dentry = NULL;
1013 }
1014 }
1015
1016 err = mutex_lock_interruptible(&u->readlock);
1017 if (err)
1018 goto out_path;
1019
1020 err = -EINVAL;
1021 if (u->addr)
1022 goto out_up;
1023
1024 if (name_err) {
1025 err = name_err == -EEXIST ? -EADDRINUSE : name_err;
1026 goto out_up;
1027 }
1028
1029 err = -ENOMEM;
1030 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
1031 if (!addr)
1032 goto out_up;
1033
1034 memcpy(addr->name, sunaddr, addr_len);
1035 addr->len = addr_len;
1036 addr->hash = hash ^ sk->sk_type;
1037 atomic_set(&addr->refcnt, 1);
1038
1039 if (dentry) {
1040 struct path u_path;
1041 umode_t mode = S_IFSOCK |
1042 (SOCK_INODE(sock)->i_mode & ~current_umask());
1043 err = unix_mknod(dentry, &path, mode, &u_path);
1044 if (err) {
1045 if (err == -EEXIST)
1046 err = -EADDRINUSE;
1047 unix_release_addr(addr);
1048 goto out_up;
1049 }
1050 addr->hash = UNIX_HASH_SIZE;
1051 hash = d_backing_inode(dentry)->i_ino & (UNIX_HASH_SIZE - 1);
1052 spin_lock(&unix_table_lock);
1053 u->path = u_path;
1054 list = &unix_socket_table[hash];
1055 } else {
1056 spin_lock(&unix_table_lock);
1057 err = -EADDRINUSE;
1058 if (__unix_find_socket_byname(net, sunaddr, addr_len,
1059 sk->sk_type, hash)) {
1060 unix_release_addr(addr);
1061 goto out_unlock;
1062 }
1063
1064 list = &unix_socket_table[addr->hash];
1065 }
1066
1067 err = 0;
1068 __unix_remove_socket(sk);
1069 u->addr = addr;
1070 __unix_insert_socket(list, sk);
1071
1072out_unlock:
1073 spin_unlock(&unix_table_lock);
1074out_up:
1075 mutex_unlock(&u->readlock);
1076out_path:
1077 if (dentry)
1078 done_path_create(&path, dentry);
1079
1080out:
1081 return err;
1082}
1083
1084static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1085{
1086 if (unlikely(sk1 == sk2) || !sk2) {
1087 unix_state_lock(sk1);
1088 return;
1089 }
1090 if (sk1 < sk2) {
1091 unix_state_lock(sk1);
1092 unix_state_lock_nested(sk2);
1093 } else {
1094 unix_state_lock(sk2);
1095 unix_state_lock_nested(sk1);
1096 }
1097}
1098
1099static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1100{
1101 if (unlikely(sk1 == sk2) || !sk2) {
1102 unix_state_unlock(sk1);
1103 return;
1104 }
1105 unix_state_unlock(sk1);
1106 unix_state_unlock(sk2);
1107}
1108
1109static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1110 int alen, int flags)
1111{
1112 struct sock *sk = sock->sk;
1113 struct net *net = sock_net(sk);
1114 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1115 struct sock *other;
1116 unsigned int hash;
1117 int err;
1118
1119 if (addr->sa_family != AF_UNSPEC) {
1120 err = unix_mkname(sunaddr, alen, &hash);
1121 if (err < 0)
1122 goto out;
1123 alen = err;
1124
1125 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1126 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1127 goto out;
1128
1129restart:
1130 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1131 if (!other)
1132 goto out;
1133
1134 unix_state_double_lock(sk, other);
1135
1136 /* Apparently VFS overslept socket death. Retry. */
1137 if (sock_flag(other, SOCK_DEAD)) {
1138 unix_state_double_unlock(sk, other);
1139 sock_put(other);
1140 goto restart;
1141 }
1142
1143 err = -EPERM;
1144 if (!unix_may_send(sk, other))
1145 goto out_unlock;
1146
1147 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1148 if (err)
1149 goto out_unlock;
1150
1151 } else {
1152 /*
1153 * 1003.1g breaking connected state with AF_UNSPEC
1154 */
1155 other = NULL;
1156 unix_state_double_lock(sk, other);
1157 }
1158
1159 /*
1160 * If it was connected, reconnect.
1161 */
1162 if (unix_peer(sk)) {
1163 struct sock *old_peer = unix_peer(sk);
1164 unix_peer(sk) = other;
1165 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1166
1167 unix_state_double_unlock(sk, other);
1168
1169 if (other != old_peer)
1170 unix_dgram_disconnected(sk, old_peer);
1171 sock_put(old_peer);
1172 } else {
1173 unix_peer(sk) = other;
1174 unix_state_double_unlock(sk, other);
1175 }
1176 return 0;
1177
1178out_unlock:
1179 unix_state_double_unlock(sk, other);
1180 sock_put(other);
1181out:
1182 return err;
1183}
1184
1185static long unix_wait_for_peer(struct sock *other, long timeo)
1186{
1187 struct unix_sock *u = unix_sk(other);
1188 int sched;
1189 DEFINE_WAIT(wait);
1190
1191 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1192
1193 sched = !sock_flag(other, SOCK_DEAD) &&
1194 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1195 unix_recvq_full(other);
1196
1197 unix_state_unlock(other);
1198
1199 if (sched)
1200 timeo = schedule_timeout(timeo);
1201
1202 finish_wait(&u->peer_wait, &wait);
1203 return timeo;
1204}
1205
1206static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1207 int addr_len, int flags)
1208{
1209 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1210 struct sock *sk = sock->sk;
1211 struct net *net = sock_net(sk);
1212 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1213 struct sock *newsk = NULL;
1214 struct sock *other = NULL;
1215 struct sk_buff *skb = NULL;
1216 unsigned int hash;
1217 int st;
1218 int err;
1219 long timeo;
1220
1221 err = unix_mkname(sunaddr, addr_len, &hash);
1222 if (err < 0)
1223 goto out;
1224 addr_len = err;
1225
1226 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1227 (err = unix_autobind(sock)) != 0)
1228 goto out;
1229
1230 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1231
1232 /* First of all allocate resources.
1233 If we will make it after state is locked,
1234 we will have to recheck all again in any case.
1235 */
1236
1237 err = -ENOMEM;
1238
1239 /* create new sock for complete connection */
1240 newsk = unix_create1(sock_net(sk), NULL, 0);
1241 if (newsk == NULL)
1242 goto out;
1243
1244 /* Allocate skb for sending to listening sock */
1245 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1246 if (skb == NULL)
1247 goto out;
1248
1249restart:
1250 /* Find listening sock. */
1251 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1252 if (!other)
1253 goto out;
1254
1255 /* Latch state of peer */
1256 unix_state_lock(other);
1257
1258 /* Apparently VFS overslept socket death. Retry. */
1259 if (sock_flag(other, SOCK_DEAD)) {
1260 unix_state_unlock(other);
1261 sock_put(other);
1262 goto restart;
1263 }
1264
1265 err = -ECONNREFUSED;
1266 if (other->sk_state != TCP_LISTEN)
1267 goto out_unlock;
1268 if (other->sk_shutdown & RCV_SHUTDOWN)
1269 goto out_unlock;
1270
1271 if (unix_recvq_full(other)) {
1272 err = -EAGAIN;
1273 if (!timeo)
1274 goto out_unlock;
1275
1276 timeo = unix_wait_for_peer(other, timeo);
1277
1278 err = sock_intr_errno(timeo);
1279 if (signal_pending(current))
1280 goto out;
1281 sock_put(other);
1282 goto restart;
1283 }
1284
1285 /* Latch our state.
1286
1287 It is tricky place. We need to grab our state lock and cannot
1288 drop lock on peer. It is dangerous because deadlock is
1289 possible. Connect to self case and simultaneous
1290 attempt to connect are eliminated by checking socket
1291 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1292 check this before attempt to grab lock.
1293
1294 Well, and we have to recheck the state after socket locked.
1295 */
1296 st = sk->sk_state;
1297
1298 switch (st) {
1299 case TCP_CLOSE:
1300 /* This is ok... continue with connect */
1301 break;
1302 case TCP_ESTABLISHED:
1303 /* Socket is already connected */
1304 err = -EISCONN;
1305 goto out_unlock;
1306 default:
1307 err = -EINVAL;
1308 goto out_unlock;
1309 }
1310
1311 unix_state_lock_nested(sk);
1312
1313 if (sk->sk_state != st) {
1314 unix_state_unlock(sk);
1315 unix_state_unlock(other);
1316 sock_put(other);
1317 goto restart;
1318 }
1319
1320 err = security_unix_stream_connect(sk, other, newsk);
1321 if (err) {
1322 unix_state_unlock(sk);
1323 goto out_unlock;
1324 }
1325
1326 /* The way is open! Fastly set all the necessary fields... */
1327
1328 sock_hold(sk);
1329 unix_peer(newsk) = sk;
1330 newsk->sk_state = TCP_ESTABLISHED;
1331 newsk->sk_type = sk->sk_type;
1332 init_peercred(newsk);
1333 newu = unix_sk(newsk);
1334 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1335 otheru = unix_sk(other);
1336
1337 /* copy address information from listening to new sock*/
1338 if (otheru->addr) {
1339 atomic_inc(&otheru->addr->refcnt);
1340 newu->addr = otheru->addr;
1341 }
1342 if (otheru->path.dentry) {
1343 path_get(&otheru->path);
1344 newu->path = otheru->path;
1345 }
1346
1347 /* Set credentials */
1348 copy_peercred(sk, other);
1349
1350 sock->state = SS_CONNECTED;
1351 sk->sk_state = TCP_ESTABLISHED;
1352 sock_hold(newsk);
1353
1354 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1355 unix_peer(sk) = newsk;
1356
1357 unix_state_unlock(sk);
1358
1359 /* take ten and and send info to listening sock */
1360 spin_lock(&other->sk_receive_queue.lock);
1361 __skb_queue_tail(&other->sk_receive_queue, skb);
1362 spin_unlock(&other->sk_receive_queue.lock);
1363 unix_state_unlock(other);
1364 other->sk_data_ready(other);
1365 sock_put(other);
1366 return 0;
1367
1368out_unlock:
1369 if (other)
1370 unix_state_unlock(other);
1371
1372out:
1373 kfree_skb(skb);
1374 if (newsk)
1375 unix_release_sock(newsk, 0);
1376 if (other)
1377 sock_put(other);
1378 return err;
1379}
1380
1381static int unix_socketpair(struct socket *socka, struct socket *sockb)
1382{
1383 struct sock *ska = socka->sk, *skb = sockb->sk;
1384
1385 /* Join our sockets back to back */
1386 sock_hold(ska);
1387 sock_hold(skb);
1388 unix_peer(ska) = skb;
1389 unix_peer(skb) = ska;
1390 init_peercred(ska);
1391 init_peercred(skb);
1392
1393 if (ska->sk_type != SOCK_DGRAM) {
1394 ska->sk_state = TCP_ESTABLISHED;
1395 skb->sk_state = TCP_ESTABLISHED;
1396 socka->state = SS_CONNECTED;
1397 sockb->state = SS_CONNECTED;
1398 }
1399 return 0;
1400}
1401
1402static void unix_sock_inherit_flags(const struct socket *old,
1403 struct socket *new)
1404{
1405 if (test_bit(SOCK_PASSCRED, &old->flags))
1406 set_bit(SOCK_PASSCRED, &new->flags);
1407 if (test_bit(SOCK_PASSSEC, &old->flags))
1408 set_bit(SOCK_PASSSEC, &new->flags);
1409}
1410
1411static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1412{
1413 struct sock *sk = sock->sk;
1414 struct sock *tsk;
1415 struct sk_buff *skb;
1416 int err;
1417
1418 err = -EOPNOTSUPP;
1419 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1420 goto out;
1421
1422 err = -EINVAL;
1423 if (sk->sk_state != TCP_LISTEN)
1424 goto out;
1425
1426 /* If socket state is TCP_LISTEN it cannot change (for now...),
1427 * so that no locks are necessary.
1428 */
1429
1430 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1431 if (!skb) {
1432 /* This means receive shutdown. */
1433 if (err == 0)
1434 err = -EINVAL;
1435 goto out;
1436 }
1437
1438 tsk = skb->sk;
1439 skb_free_datagram(sk, skb);
1440 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1441
1442 /* attach accepted sock to socket */
1443 unix_state_lock(tsk);
1444 newsock->state = SS_CONNECTED;
1445 unix_sock_inherit_flags(sock, newsock);
1446 sock_graft(tsk, newsock);
1447 unix_state_unlock(tsk);
1448 return 0;
1449
1450out:
1451 return err;
1452}
1453
1454
1455static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1456{
1457 struct sock *sk = sock->sk;
1458 struct unix_sock *u;
1459 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1460 int err = 0;
1461
1462 if (peer) {
1463 sk = unix_peer_get(sk);
1464
1465 err = -ENOTCONN;
1466 if (!sk)
1467 goto out;
1468 err = 0;
1469 } else {
1470 sock_hold(sk);
1471 }
1472
1473 u = unix_sk(sk);
1474 unix_state_lock(sk);
1475 if (!u->addr) {
1476 sunaddr->sun_family = AF_UNIX;
1477 sunaddr->sun_path[0] = 0;
1478 *uaddr_len = sizeof(short);
1479 } else {
1480 struct unix_address *addr = u->addr;
1481
1482 *uaddr_len = addr->len;
1483 memcpy(sunaddr, addr->name, *uaddr_len);
1484 }
1485 unix_state_unlock(sk);
1486 sock_put(sk);
1487out:
1488 return err;
1489}
1490
1491static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1492{
1493 int i;
1494
1495 scm->fp = UNIXCB(skb).fp;
1496 UNIXCB(skb).fp = NULL;
1497
1498 for (i = scm->fp->count-1; i >= 0; i--)
1499 unix_notinflight(scm->fp->user, scm->fp->fp[i]);
1500}
1501
1502static void unix_destruct_scm(struct sk_buff *skb)
1503{
1504 struct scm_cookie scm;
1505 memset(&scm, 0, sizeof(scm));
1506 scm.pid = UNIXCB(skb).pid;
1507 if (UNIXCB(skb).fp)
1508 unix_detach_fds(&scm, skb);
1509
1510 /* Alas, it calls VFS */
1511 /* So fscking what? fput() had been SMP-safe since the last Summer */
1512 scm_destroy(&scm);
1513 sock_wfree(skb);
1514}
1515
1516/*
1517 * The "user->unix_inflight" variable is protected by the garbage
1518 * collection lock, and we just read it locklessly here. If you go
1519 * over the limit, there might be a tiny race in actually noticing
1520 * it across threads. Tough.
1521 */
1522static inline bool too_many_unix_fds(struct task_struct *p)
1523{
1524 struct user_struct *user = current_user();
1525
1526 if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
1527 return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1528 return false;
1529}
1530
1531#define MAX_RECURSION_LEVEL 4
1532
1533static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1534{
1535 int i;
1536 unsigned char max_level = 0;
1537
1538 if (too_many_unix_fds(current))
1539 return -ETOOMANYREFS;
1540
1541 for (i = scm->fp->count - 1; i >= 0; i--) {
1542 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1543
1544 if (sk)
1545 max_level = max(max_level,
1546 unix_sk(sk)->recursion_level);
1547 }
1548 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1549 return -ETOOMANYREFS;
1550
1551 /*
1552 * Need to duplicate file references for the sake of garbage
1553 * collection. Otherwise a socket in the fps might become a
1554 * candidate for GC while the skb is not yet queued.
1555 */
1556 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1557 if (!UNIXCB(skb).fp)
1558 return -ENOMEM;
1559
1560 for (i = scm->fp->count - 1; i >= 0; i--)
1561 unix_inflight(scm->fp->user, scm->fp->fp[i]);
1562 return max_level;
1563}
1564
1565static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1566{
1567 int err = 0;
1568
1569 UNIXCB(skb).pid = get_pid(scm->pid);
1570 UNIXCB(skb).uid = scm->creds.uid;
1571 UNIXCB(skb).gid = scm->creds.gid;
1572 UNIXCB(skb).fp = NULL;
1573 unix_get_secdata(scm, skb);
1574 if (scm->fp && send_fds)
1575 err = unix_attach_fds(scm, skb);
1576
1577 skb->destructor = unix_destruct_scm;
1578 return err;
1579}
1580
1581static bool unix_passcred_enabled(const struct socket *sock,
1582 const struct sock *other)
1583{
1584 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1585 !other->sk_socket ||
1586 test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1587}
1588
1589/*
1590 * Some apps rely on write() giving SCM_CREDENTIALS
1591 * We include credentials if source or destination socket
1592 * asserted SOCK_PASSCRED.
1593 */
1594static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1595 const struct sock *other)
1596{
1597 if (UNIXCB(skb).pid)
1598 return;
1599 if (unix_passcred_enabled(sock, other)) {
1600 UNIXCB(skb).pid = get_pid(task_tgid(current));
1601 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1602 }
1603}
1604
1605static int maybe_init_creds(struct scm_cookie *scm,
1606 struct socket *socket,
1607 const struct sock *other)
1608{
1609 int err;
1610 struct msghdr msg = { .msg_controllen = 0 };
1611
1612 err = scm_send(socket, &msg, scm, false);
1613 if (err)
1614 return err;
1615
1616 if (unix_passcred_enabled(socket, other)) {
1617 scm->pid = get_pid(task_tgid(current));
1618 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1619 }
1620 return err;
1621}
1622
1623static bool unix_skb_scm_eq(struct sk_buff *skb,
1624 struct scm_cookie *scm)
1625{
1626 const struct unix_skb_parms *u = &UNIXCB(skb);
1627
1628 return u->pid == scm->pid &&
1629 uid_eq(u->uid, scm->creds.uid) &&
1630 gid_eq(u->gid, scm->creds.gid) &&
1631 unix_secdata_eq(scm, skb);
1632}
1633
1634/*
1635 * Send AF_UNIX data.
1636 */
1637
1638static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1639 size_t len)
1640{
1641 struct sock *sk = sock->sk;
1642 struct net *net = sock_net(sk);
1643 struct unix_sock *u = unix_sk(sk);
1644 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1645 struct sock *other = NULL;
1646 int namelen = 0; /* fake GCC */
1647 int err;
1648 unsigned int hash;
1649 struct sk_buff *skb;
1650 long timeo;
1651 struct scm_cookie scm;
1652 int max_level;
1653 int data_len = 0;
1654 int sk_locked;
1655
1656 wait_for_unix_gc();
1657 err = scm_send(sock, msg, &scm, false);
1658 if (err < 0)
1659 return err;
1660
1661 err = -EOPNOTSUPP;
1662 if (msg->msg_flags&MSG_OOB)
1663 goto out;
1664
1665 if (msg->msg_namelen) {
1666 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1667 if (err < 0)
1668 goto out;
1669 namelen = err;
1670 } else {
1671 sunaddr = NULL;
1672 err = -ENOTCONN;
1673 other = unix_peer_get(sk);
1674 if (!other)
1675 goto out;
1676 }
1677
1678 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1679 && (err = unix_autobind(sock)) != 0)
1680 goto out;
1681
1682 err = -EMSGSIZE;
1683 if (len > sk->sk_sndbuf - 32)
1684 goto out;
1685
1686 if (len > SKB_MAX_ALLOC) {
1687 data_len = min_t(size_t,
1688 len - SKB_MAX_ALLOC,
1689 MAX_SKB_FRAGS * PAGE_SIZE);
1690 data_len = PAGE_ALIGN(data_len);
1691
1692 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1693 }
1694
1695 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1696 msg->msg_flags & MSG_DONTWAIT, &err,
1697 PAGE_ALLOC_COSTLY_ORDER);
1698 if (skb == NULL)
1699 goto out;
1700
1701 err = unix_scm_to_skb(&scm, skb, true);
1702 if (err < 0)
1703 goto out_free;
1704 max_level = err + 1;
1705
1706 skb_put(skb, len - data_len);
1707 skb->data_len = data_len;
1708 skb->len = len;
1709 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1710 if (err)
1711 goto out_free;
1712
1713 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1714
1715restart:
1716 if (!other) {
1717 err = -ECONNRESET;
1718 if (sunaddr == NULL)
1719 goto out_free;
1720
1721 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1722 hash, &err);
1723 if (other == NULL)
1724 goto out_free;
1725 }
1726
1727 if (sk_filter(other, skb) < 0) {
1728 /* Toss the packet but do not return any error to the sender */
1729 err = len;
1730 goto out_free;
1731 }
1732
1733 sk_locked = 0;
1734 unix_state_lock(other);
1735restart_locked:
1736 err = -EPERM;
1737 if (!unix_may_send(sk, other))
1738 goto out_unlock;
1739
1740 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1741 /*
1742 * Check with 1003.1g - what should
1743 * datagram error
1744 */
1745 unix_state_unlock(other);
1746 sock_put(other);
1747
1748 if (!sk_locked)
1749 unix_state_lock(sk);
1750
1751 err = 0;
1752 if (unix_peer(sk) == other) {
1753 unix_peer(sk) = NULL;
1754 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1755
1756 unix_state_unlock(sk);
1757
1758 unix_dgram_disconnected(sk, other);
1759 sock_put(other);
1760 err = -ECONNREFUSED;
1761 } else {
1762 unix_state_unlock(sk);
1763 }
1764
1765 other = NULL;
1766 if (err)
1767 goto out_free;
1768 goto restart;
1769 }
1770
1771 err = -EPIPE;
1772 if (other->sk_shutdown & RCV_SHUTDOWN)
1773 goto out_unlock;
1774
1775 if (sk->sk_type != SOCK_SEQPACKET) {
1776 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1777 if (err)
1778 goto out_unlock;
1779 }
1780
1781 /* other == sk && unix_peer(other) != sk if
1782 * - unix_peer(sk) == NULL, destination address bound to sk
1783 * - unix_peer(sk) == sk by time of get but disconnected before lock
1784 */
1785 if (other != sk &&
1786 unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1787 if (timeo) {
1788 timeo = unix_wait_for_peer(other, timeo);
1789
1790 err = sock_intr_errno(timeo);
1791 if (signal_pending(current))
1792 goto out_free;
1793
1794 goto restart;
1795 }
1796
1797 if (!sk_locked) {
1798 unix_state_unlock(other);
1799 unix_state_double_lock(sk, other);
1800 }
1801
1802 if (unix_peer(sk) != other ||
1803 unix_dgram_peer_wake_me(sk, other)) {
1804 err = -EAGAIN;
1805 sk_locked = 1;
1806 goto out_unlock;
1807 }
1808
1809 if (!sk_locked) {
1810 sk_locked = 1;
1811 goto restart_locked;
1812 }
1813 }
1814
1815 if (unlikely(sk_locked))
1816 unix_state_unlock(sk);
1817
1818 if (sock_flag(other, SOCK_RCVTSTAMP))
1819 __net_timestamp(skb);
1820 maybe_add_creds(skb, sock, other);
1821 skb_queue_tail(&other->sk_receive_queue, skb);
1822 if (max_level > unix_sk(other)->recursion_level)
1823 unix_sk(other)->recursion_level = max_level;
1824 unix_state_unlock(other);
1825 other->sk_data_ready(other);
1826 sock_put(other);
1827 scm_destroy(&scm);
1828 return len;
1829
1830out_unlock:
1831 if (sk_locked)
1832 unix_state_unlock(sk);
1833 unix_state_unlock(other);
1834out_free:
1835 kfree_skb(skb);
1836out:
1837 if (other)
1838 sock_put(other);
1839 scm_destroy(&scm);
1840 return err;
1841}
1842
1843/* We use paged skbs for stream sockets, and limit occupancy to 32768
1844 * bytes, and a minimun of a full page.
1845 */
1846#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1847
1848static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
1849 size_t len)
1850{
1851 struct sock *sk = sock->sk;
1852 struct sock *other = NULL;
1853 int err, size;
1854 struct sk_buff *skb;
1855 int sent = 0;
1856 struct scm_cookie scm;
1857 bool fds_sent = false;
1858 int max_level;
1859 int data_len;
1860
1861 wait_for_unix_gc();
1862 err = scm_send(sock, msg, &scm, false);
1863 if (err < 0)
1864 return err;
1865
1866 err = -EOPNOTSUPP;
1867 if (msg->msg_flags&MSG_OOB)
1868 goto out_err;
1869
1870 if (msg->msg_namelen) {
1871 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1872 goto out_err;
1873 } else {
1874 err = -ENOTCONN;
1875 other = unix_peer(sk);
1876 if (!other)
1877 goto out_err;
1878 }
1879
1880 if (sk->sk_shutdown & SEND_SHUTDOWN)
1881 goto pipe_err;
1882
1883 while (sent < len) {
1884 size = len - sent;
1885
1886 /* Keep two messages in the pipe so it schedules better */
1887 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1888
1889 /* allow fallback to order-0 allocations */
1890 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1891
1892 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1893
1894 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
1895
1896 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1897 msg->msg_flags & MSG_DONTWAIT, &err,
1898 get_order(UNIX_SKB_FRAGS_SZ));
1899 if (!skb)
1900 goto out_err;
1901
1902 /* Only send the fds in the first buffer */
1903 err = unix_scm_to_skb(&scm, skb, !fds_sent);
1904 if (err < 0) {
1905 kfree_skb(skb);
1906 goto out_err;
1907 }
1908 max_level = err + 1;
1909 fds_sent = true;
1910
1911 skb_put(skb, size - data_len);
1912 skb->data_len = data_len;
1913 skb->len = size;
1914 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
1915 if (err) {
1916 kfree_skb(skb);
1917 goto out_err;
1918 }
1919
1920 unix_state_lock(other);
1921
1922 if (sock_flag(other, SOCK_DEAD) ||
1923 (other->sk_shutdown & RCV_SHUTDOWN))
1924 goto pipe_err_free;
1925
1926 maybe_add_creds(skb, sock, other);
1927 skb_queue_tail(&other->sk_receive_queue, skb);
1928 if (max_level > unix_sk(other)->recursion_level)
1929 unix_sk(other)->recursion_level = max_level;
1930 unix_state_unlock(other);
1931 other->sk_data_ready(other);
1932 sent += size;
1933 }
1934
1935 scm_destroy(&scm);
1936
1937 return sent;
1938
1939pipe_err_free:
1940 unix_state_unlock(other);
1941 kfree_skb(skb);
1942pipe_err:
1943 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1944 send_sig(SIGPIPE, current, 0);
1945 err = -EPIPE;
1946out_err:
1947 scm_destroy(&scm);
1948 return sent ? : err;
1949}
1950
1951static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
1952 int offset, size_t size, int flags)
1953{
1954 int err;
1955 bool send_sigpipe = false;
1956 bool init_scm = true;
1957 struct scm_cookie scm;
1958 struct sock *other, *sk = socket->sk;
1959 struct sk_buff *skb, *newskb = NULL, *tail = NULL;
1960
1961 if (flags & MSG_OOB)
1962 return -EOPNOTSUPP;
1963
1964 other = unix_peer(sk);
1965 if (!other || sk->sk_state != TCP_ESTABLISHED)
1966 return -ENOTCONN;
1967
1968 if (false) {
1969alloc_skb:
1970 unix_state_unlock(other);
1971 mutex_unlock(&unix_sk(other)->readlock);
1972 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
1973 &err, 0);
1974 if (!newskb)
1975 goto err;
1976 }
1977
1978 /* we must acquire readlock as we modify already present
1979 * skbs in the sk_receive_queue and mess with skb->len
1980 */
1981 err = mutex_lock_interruptible(&unix_sk(other)->readlock);
1982 if (err) {
1983 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
1984 goto err;
1985 }
1986
1987 if (sk->sk_shutdown & SEND_SHUTDOWN) {
1988 err = -EPIPE;
1989 send_sigpipe = true;
1990 goto err_unlock;
1991 }
1992
1993 unix_state_lock(other);
1994
1995 if (sock_flag(other, SOCK_DEAD) ||
1996 other->sk_shutdown & RCV_SHUTDOWN) {
1997 err = -EPIPE;
1998 send_sigpipe = true;
1999 goto err_state_unlock;
2000 }
2001
2002 if (init_scm) {
2003 err = maybe_init_creds(&scm, socket, other);
2004 if (err)
2005 goto err_state_unlock;
2006 init_scm = false;
2007 }
2008
2009 skb = skb_peek_tail(&other->sk_receive_queue);
2010 if (tail && tail == skb) {
2011 skb = newskb;
2012 } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
2013 if (newskb) {
2014 skb = newskb;
2015 } else {
2016 tail = skb;
2017 goto alloc_skb;
2018 }
2019 } else if (newskb) {
2020 /* this is fast path, we don't necessarily need to
2021 * call to kfree_skb even though with newskb == NULL
2022 * this - does no harm
2023 */
2024 consume_skb(newskb);
2025 newskb = NULL;
2026 }
2027
2028 if (skb_append_pagefrags(skb, page, offset, size)) {
2029 tail = skb;
2030 goto alloc_skb;
2031 }
2032
2033 skb->len += size;
2034 skb->data_len += size;
2035 skb->truesize += size;
2036 atomic_add(size, &sk->sk_wmem_alloc);
2037
2038 if (newskb) {
2039 err = unix_scm_to_skb(&scm, skb, false);
2040 if (err)
2041 goto err_state_unlock;
2042 spin_lock(&other->sk_receive_queue.lock);
2043 __skb_queue_tail(&other->sk_receive_queue, newskb);
2044 spin_unlock(&other->sk_receive_queue.lock);
2045 }
2046
2047 unix_state_unlock(other);
2048 mutex_unlock(&unix_sk(other)->readlock);
2049
2050 other->sk_data_ready(other);
2051 scm_destroy(&scm);
2052 return size;
2053
2054err_state_unlock:
2055 unix_state_unlock(other);
2056err_unlock:
2057 mutex_unlock(&unix_sk(other)->readlock);
2058err:
2059 kfree_skb(newskb);
2060 if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2061 send_sig(SIGPIPE, current, 0);
2062 if (!init_scm)
2063 scm_destroy(&scm);
2064 return err;
2065}
2066
2067static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2068 size_t len)
2069{
2070 int err;
2071 struct sock *sk = sock->sk;
2072
2073 err = sock_error(sk);
2074 if (err)
2075 return err;
2076
2077 if (sk->sk_state != TCP_ESTABLISHED)
2078 return -ENOTCONN;
2079
2080 if (msg->msg_namelen)
2081 msg->msg_namelen = 0;
2082
2083 return unix_dgram_sendmsg(sock, msg, len);
2084}
2085
2086static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2087 size_t size, int flags)
2088{
2089 struct sock *sk = sock->sk;
2090
2091 if (sk->sk_state != TCP_ESTABLISHED)
2092 return -ENOTCONN;
2093
2094 return unix_dgram_recvmsg(sock, msg, size, flags);
2095}
2096
2097static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2098{
2099 struct unix_sock *u = unix_sk(sk);
2100
2101 if (u->addr) {
2102 msg->msg_namelen = u->addr->len;
2103 memcpy(msg->msg_name, u->addr->name, u->addr->len);
2104 }
2105}
2106
2107static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
2108 size_t size, int flags)
2109{
2110 struct scm_cookie scm;
2111 struct sock *sk = sock->sk;
2112 struct unix_sock *u = unix_sk(sk);
2113 struct sk_buff *skb, *last;
2114 long timeo;
2115 int err;
2116 int peeked, skip;
2117
2118 err = -EOPNOTSUPP;
2119 if (flags&MSG_OOB)
2120 goto out;
2121
2122 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2123
2124 do {
2125 mutex_lock(&u->readlock);
2126
2127 skip = sk_peek_offset(sk, flags);
2128 skb = __skb_try_recv_datagram(sk, flags, &peeked, &skip, &err,
2129 &last);
2130 if (skb)
2131 break;
2132
2133 mutex_unlock(&u->readlock);
2134
2135 if (err != -EAGAIN)
2136 break;
2137 } while (timeo &&
2138 !__skb_wait_for_more_packets(sk, &err, &timeo, last));
2139
2140 if (!skb) { /* implies readlock unlocked */
2141 unix_state_lock(sk);
2142 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2143 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2144 (sk->sk_shutdown & RCV_SHUTDOWN))
2145 err = 0;
2146 unix_state_unlock(sk);
2147 goto out;
2148 }
2149
2150 if (wq_has_sleeper(&u->peer_wait))
2151 wake_up_interruptible_sync_poll(&u->peer_wait,
2152 POLLOUT | POLLWRNORM |
2153 POLLWRBAND);
2154
2155 if (msg->msg_name)
2156 unix_copy_addr(msg, skb->sk);
2157
2158 if (size > skb->len - skip)
2159 size = skb->len - skip;
2160 else if (size < skb->len - skip)
2161 msg->msg_flags |= MSG_TRUNC;
2162
2163 err = skb_copy_datagram_msg(skb, skip, msg, size);
2164 if (err)
2165 goto out_free;
2166
2167 if (sock_flag(sk, SOCK_RCVTSTAMP))
2168 __sock_recv_timestamp(msg, sk, skb);
2169
2170 memset(&scm, 0, sizeof(scm));
2171
2172 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2173 unix_set_secdata(&scm, skb);
2174
2175 if (!(flags & MSG_PEEK)) {
2176 if (UNIXCB(skb).fp)
2177 unix_detach_fds(&scm, skb);
2178
2179 sk_peek_offset_bwd(sk, skb->len);
2180 } else {
2181 /* It is questionable: on PEEK we could:
2182 - do not return fds - good, but too simple 8)
2183 - return fds, and do not return them on read (old strategy,
2184 apparently wrong)
2185 - clone fds (I chose it for now, it is the most universal
2186 solution)
2187
2188 POSIX 1003.1g does not actually define this clearly
2189 at all. POSIX 1003.1g doesn't define a lot of things
2190 clearly however!
2191
2192 */
2193
2194 sk_peek_offset_fwd(sk, size);
2195
2196 if (UNIXCB(skb).fp)
2197 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2198 }
2199 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2200
2201 scm_recv(sock, msg, &scm, flags);
2202
2203out_free:
2204 skb_free_datagram(sk, skb);
2205 mutex_unlock(&u->readlock);
2206out:
2207 return err;
2208}
2209
2210/*
2211 * Sleep until more data has arrived. But check for races..
2212 */
2213static long unix_stream_data_wait(struct sock *sk, long timeo,
2214 struct sk_buff *last, unsigned int last_len)
2215{
2216 struct sk_buff *tail;
2217 DEFINE_WAIT(wait);
2218
2219 unix_state_lock(sk);
2220
2221 for (;;) {
2222 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2223
2224 tail = skb_peek_tail(&sk->sk_receive_queue);
2225 if (tail != last ||
2226 (tail && tail->len != last_len) ||
2227 sk->sk_err ||
2228 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2229 signal_pending(current) ||
2230 !timeo)
2231 break;
2232
2233 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2234 unix_state_unlock(sk);
2235 timeo = freezable_schedule_timeout(timeo);
2236 unix_state_lock(sk);
2237
2238 if (sock_flag(sk, SOCK_DEAD))
2239 break;
2240
2241 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2242 }
2243
2244 finish_wait(sk_sleep(sk), &wait);
2245 unix_state_unlock(sk);
2246 return timeo;
2247}
2248
2249static unsigned int unix_skb_len(const struct sk_buff *skb)
2250{
2251 return skb->len - UNIXCB(skb).consumed;
2252}
2253
2254struct unix_stream_read_state {
2255 int (*recv_actor)(struct sk_buff *, int, int,
2256 struct unix_stream_read_state *);
2257 struct socket *socket;
2258 struct msghdr *msg;
2259 struct pipe_inode_info *pipe;
2260 size_t size;
2261 int flags;
2262 unsigned int splice_flags;
2263};
2264
2265static int unix_stream_read_generic(struct unix_stream_read_state *state)
2266{
2267 struct scm_cookie scm;
2268 struct socket *sock = state->socket;
2269 struct sock *sk = sock->sk;
2270 struct unix_sock *u = unix_sk(sk);
2271 int copied = 0;
2272 int flags = state->flags;
2273 int noblock = flags & MSG_DONTWAIT;
2274 bool check_creds = false;
2275 int target;
2276 int err = 0;
2277 long timeo;
2278 int skip;
2279 size_t size = state->size;
2280 unsigned int last_len;
2281
2282 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2283 err = -EINVAL;
2284 goto out;
2285 }
2286
2287 if (unlikely(flags & MSG_OOB)) {
2288 err = -EOPNOTSUPP;
2289 goto out;
2290 }
2291
2292 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2293 timeo = sock_rcvtimeo(sk, noblock);
2294
2295 memset(&scm, 0, sizeof(scm));
2296
2297 /* Lock the socket to prevent queue disordering
2298 * while sleeps in memcpy_tomsg
2299 */
2300 mutex_lock(&u->readlock);
2301
2302 if (flags & MSG_PEEK)
2303 skip = sk_peek_offset(sk, flags);
2304 else
2305 skip = 0;
2306
2307 do {
2308 int chunk;
2309 bool drop_skb;
2310 struct sk_buff *skb, *last;
2311
2312redo:
2313 unix_state_lock(sk);
2314 if (sock_flag(sk, SOCK_DEAD)) {
2315 err = -ECONNRESET;
2316 goto unlock;
2317 }
2318 last = skb = skb_peek(&sk->sk_receive_queue);
2319 last_len = last ? last->len : 0;
2320again:
2321 if (skb == NULL) {
2322 unix_sk(sk)->recursion_level = 0;
2323 if (copied >= target)
2324 goto unlock;
2325
2326 /*
2327 * POSIX 1003.1g mandates this order.
2328 */
2329
2330 err = sock_error(sk);
2331 if (err)
2332 goto unlock;
2333 if (sk->sk_shutdown & RCV_SHUTDOWN)
2334 goto unlock;
2335
2336 unix_state_unlock(sk);
2337 if (!timeo) {
2338 err = -EAGAIN;
2339 break;
2340 }
2341
2342 mutex_unlock(&u->readlock);
2343
2344 timeo = unix_stream_data_wait(sk, timeo, last,
2345 last_len);
2346
2347 if (signal_pending(current)) {
2348 err = sock_intr_errno(timeo);
2349 scm_destroy(&scm);
2350 goto out;
2351 }
2352
2353 mutex_lock(&u->readlock);
2354 goto redo;
2355unlock:
2356 unix_state_unlock(sk);
2357 break;
2358 }
2359
2360 while (skip >= unix_skb_len(skb)) {
2361 skip -= unix_skb_len(skb);
2362 last = skb;
2363 last_len = skb->len;
2364 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2365 if (!skb)
2366 goto again;
2367 }
2368
2369 unix_state_unlock(sk);
2370
2371 if (check_creds) {
2372 /* Never glue messages from different writers */
2373 if (!unix_skb_scm_eq(skb, &scm))
2374 break;
2375 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2376 /* Copy credentials */
2377 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2378 unix_set_secdata(&scm, skb);
2379 check_creds = true;
2380 }
2381
2382 /* Copy address just once */
2383 if (state->msg && state->msg->msg_name) {
2384 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2385 state->msg->msg_name);
2386 unix_copy_addr(state->msg, skb->sk);
2387 sunaddr = NULL;
2388 }
2389
2390 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2391 skb_get(skb);
2392 chunk = state->recv_actor(skb, skip, chunk, state);
2393 drop_skb = !unix_skb_len(skb);
2394 /* skb is only safe to use if !drop_skb */
2395 consume_skb(skb);
2396 if (chunk < 0) {
2397 if (copied == 0)
2398 copied = -EFAULT;
2399 break;
2400 }
2401 copied += chunk;
2402 size -= chunk;
2403
2404 if (drop_skb) {
2405 /* the skb was touched by a concurrent reader;
2406 * we should not expect anything from this skb
2407 * anymore and assume it invalid - we can be
2408 * sure it was dropped from the socket queue
2409 *
2410 * let's report a short read
2411 */
2412 err = 0;
2413 break;
2414 }
2415
2416 /* Mark read part of skb as used */
2417 if (!(flags & MSG_PEEK)) {
2418 UNIXCB(skb).consumed += chunk;
2419
2420 sk_peek_offset_bwd(sk, chunk);
2421
2422 if (UNIXCB(skb).fp)
2423 unix_detach_fds(&scm, skb);
2424
2425 if (unix_skb_len(skb))
2426 break;
2427
2428 skb_unlink(skb, &sk->sk_receive_queue);
2429 consume_skb(skb);
2430
2431 if (scm.fp)
2432 break;
2433 } else {
2434 /* It is questionable, see note in unix_dgram_recvmsg.
2435 */
2436 if (UNIXCB(skb).fp)
2437 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2438
2439 sk_peek_offset_fwd(sk, chunk);
2440
2441 if (UNIXCB(skb).fp)
2442 break;
2443
2444 skip = 0;
2445 last = skb;
2446 last_len = skb->len;
2447 unix_state_lock(sk);
2448 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2449 if (skb)
2450 goto again;
2451 unix_state_unlock(sk);
2452 break;
2453 }
2454 } while (size);
2455
2456 mutex_unlock(&u->readlock);
2457 if (state->msg)
2458 scm_recv(sock, state->msg, &scm, flags);
2459 else
2460 scm_destroy(&scm);
2461out:
2462 return copied ? : err;
2463}
2464
2465static int unix_stream_read_actor(struct sk_buff *skb,
2466 int skip, int chunk,
2467 struct unix_stream_read_state *state)
2468{
2469 int ret;
2470
2471 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2472 state->msg, chunk);
2473 return ret ?: chunk;
2474}
2475
2476static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2477 size_t size, int flags)
2478{
2479 struct unix_stream_read_state state = {
2480 .recv_actor = unix_stream_read_actor,
2481 .socket = sock,
2482 .msg = msg,
2483 .size = size,
2484 .flags = flags
2485 };
2486
2487 return unix_stream_read_generic(&state);
2488}
2489
2490static ssize_t skb_unix_socket_splice(struct sock *sk,
2491 struct pipe_inode_info *pipe,
2492 struct splice_pipe_desc *spd)
2493{
2494 int ret;
2495 struct unix_sock *u = unix_sk(sk);
2496
2497 mutex_unlock(&u->readlock);
2498 ret = splice_to_pipe(pipe, spd);
2499 mutex_lock(&u->readlock);
2500
2501 return ret;
2502}
2503
2504static int unix_stream_splice_actor(struct sk_buff *skb,
2505 int skip, int chunk,
2506 struct unix_stream_read_state *state)
2507{
2508 return skb_splice_bits(skb, state->socket->sk,
2509 UNIXCB(skb).consumed + skip,
2510 state->pipe, chunk, state->splice_flags,
2511 skb_unix_socket_splice);
2512}
2513
2514static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2515 struct pipe_inode_info *pipe,
2516 size_t size, unsigned int flags)
2517{
2518 struct unix_stream_read_state state = {
2519 .recv_actor = unix_stream_splice_actor,
2520 .socket = sock,
2521 .pipe = pipe,
2522 .size = size,
2523 .splice_flags = flags,
2524 };
2525
2526 if (unlikely(*ppos))
2527 return -ESPIPE;
2528
2529 if (sock->file->f_flags & O_NONBLOCK ||
2530 flags & SPLICE_F_NONBLOCK)
2531 state.flags = MSG_DONTWAIT;
2532
2533 return unix_stream_read_generic(&state);
2534}
2535
2536static int unix_shutdown(struct socket *sock, int mode)
2537{
2538 struct sock *sk = sock->sk;
2539 struct sock *other;
2540
2541 if (mode < SHUT_RD || mode > SHUT_RDWR)
2542 return -EINVAL;
2543 /* This maps:
2544 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2545 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2546 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2547 */
2548 ++mode;
2549
2550 unix_state_lock(sk);
2551 sk->sk_shutdown |= mode;
2552 other = unix_peer(sk);
2553 if (other)
2554 sock_hold(other);
2555 unix_state_unlock(sk);
2556 sk->sk_state_change(sk);
2557
2558 if (other &&
2559 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2560
2561 int peer_mode = 0;
2562
2563 if (mode&RCV_SHUTDOWN)
2564 peer_mode |= SEND_SHUTDOWN;
2565 if (mode&SEND_SHUTDOWN)
2566 peer_mode |= RCV_SHUTDOWN;
2567 unix_state_lock(other);
2568 other->sk_shutdown |= peer_mode;
2569 unix_state_unlock(other);
2570 other->sk_state_change(other);
2571 if (peer_mode == SHUTDOWN_MASK)
2572 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2573 else if (peer_mode & RCV_SHUTDOWN)
2574 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2575 }
2576 if (other)
2577 sock_put(other);
2578
2579 return 0;
2580}
2581
2582long unix_inq_len(struct sock *sk)
2583{
2584 struct sk_buff *skb;
2585 long amount = 0;
2586
2587 if (sk->sk_state == TCP_LISTEN)
2588 return -EINVAL;
2589
2590 spin_lock(&sk->sk_receive_queue.lock);
2591 if (sk->sk_type == SOCK_STREAM ||
2592 sk->sk_type == SOCK_SEQPACKET) {
2593 skb_queue_walk(&sk->sk_receive_queue, skb)
2594 amount += unix_skb_len(skb);
2595 } else {
2596 skb = skb_peek(&sk->sk_receive_queue);
2597 if (skb)
2598 amount = skb->len;
2599 }
2600 spin_unlock(&sk->sk_receive_queue.lock);
2601
2602 return amount;
2603}
2604EXPORT_SYMBOL_GPL(unix_inq_len);
2605
2606long unix_outq_len(struct sock *sk)
2607{
2608 return sk_wmem_alloc_get(sk);
2609}
2610EXPORT_SYMBOL_GPL(unix_outq_len);
2611
2612static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2613{
2614 struct sock *sk = sock->sk;
2615 long amount = 0;
2616 int err;
2617
2618 switch (cmd) {
2619 case SIOCOUTQ:
2620 amount = unix_outq_len(sk);
2621 err = put_user(amount, (int __user *)arg);
2622 break;
2623 case SIOCINQ:
2624 amount = unix_inq_len(sk);
2625 if (amount < 0)
2626 err = amount;
2627 else
2628 err = put_user(amount, (int __user *)arg);
2629 break;
2630 default:
2631 err = -ENOIOCTLCMD;
2632 break;
2633 }
2634 return err;
2635}
2636
2637static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2638{
2639 struct sock *sk = sock->sk;
2640 unsigned int mask;
2641
2642 sock_poll_wait(file, sk_sleep(sk), wait);
2643 mask = 0;
2644
2645 /* exceptional events? */
2646 if (sk->sk_err)
2647 mask |= POLLERR;
2648 if (sk->sk_shutdown == SHUTDOWN_MASK)
2649 mask |= POLLHUP;
2650 if (sk->sk_shutdown & RCV_SHUTDOWN)
2651 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2652
2653 /* readable? */
2654 if (!skb_queue_empty(&sk->sk_receive_queue))
2655 mask |= POLLIN | POLLRDNORM;
2656
2657 /* Connection-based need to check for termination and startup */
2658 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2659 sk->sk_state == TCP_CLOSE)
2660 mask |= POLLHUP;
2661
2662 /*
2663 * we set writable also when the other side has shut down the
2664 * connection. This prevents stuck sockets.
2665 */
2666 if (unix_writable(sk))
2667 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2668
2669 return mask;
2670}
2671
2672static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2673 poll_table *wait)
2674{
2675 struct sock *sk = sock->sk, *other;
2676 unsigned int mask, writable;
2677
2678 sock_poll_wait(file, sk_sleep(sk), wait);
2679 mask = 0;
2680
2681 /* exceptional events? */
2682 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2683 mask |= POLLERR |
2684 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2685
2686 if (sk->sk_shutdown & RCV_SHUTDOWN)
2687 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2688 if (sk->sk_shutdown == SHUTDOWN_MASK)
2689 mask |= POLLHUP;
2690
2691 /* readable? */
2692 if (!skb_queue_empty(&sk->sk_receive_queue))
2693 mask |= POLLIN | POLLRDNORM;
2694
2695 /* Connection-based need to check for termination and startup */
2696 if (sk->sk_type == SOCK_SEQPACKET) {
2697 if (sk->sk_state == TCP_CLOSE)
2698 mask |= POLLHUP;
2699 /* connection hasn't started yet? */
2700 if (sk->sk_state == TCP_SYN_SENT)
2701 return mask;
2702 }
2703
2704 /* No write status requested, avoid expensive OUT tests. */
2705 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
2706 return mask;
2707
2708 writable = unix_writable(sk);
2709 if (writable) {
2710 unix_state_lock(sk);
2711
2712 other = unix_peer(sk);
2713 if (other && unix_peer(other) != sk &&
2714 unix_recvq_full(other) &&
2715 unix_dgram_peer_wake_me(sk, other))
2716 writable = 0;
2717
2718 unix_state_unlock(sk);
2719 }
2720
2721 if (writable)
2722 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2723 else
2724 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2725
2726 return mask;
2727}
2728
2729#ifdef CONFIG_PROC_FS
2730
2731#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2732
2733#define get_bucket(x) ((x) >> BUCKET_SPACE)
2734#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2735#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2736
2737static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2738{
2739 unsigned long offset = get_offset(*pos);
2740 unsigned long bucket = get_bucket(*pos);
2741 struct sock *sk;
2742 unsigned long count = 0;
2743
2744 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2745 if (sock_net(sk) != seq_file_net(seq))
2746 continue;
2747 if (++count == offset)
2748 break;
2749 }
2750
2751 return sk;
2752}
2753
2754static struct sock *unix_next_socket(struct seq_file *seq,
2755 struct sock *sk,
2756 loff_t *pos)
2757{
2758 unsigned long bucket;
2759
2760 while (sk > (struct sock *)SEQ_START_TOKEN) {
2761 sk = sk_next(sk);
2762 if (!sk)
2763 goto next_bucket;
2764 if (sock_net(sk) == seq_file_net(seq))
2765 return sk;
2766 }
2767
2768 do {
2769 sk = unix_from_bucket(seq, pos);
2770 if (sk)
2771 return sk;
2772
2773next_bucket:
2774 bucket = get_bucket(*pos) + 1;
2775 *pos = set_bucket_offset(bucket, 1);
2776 } while (bucket < ARRAY_SIZE(unix_socket_table));
2777
2778 return NULL;
2779}
2780
2781static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2782 __acquires(unix_table_lock)
2783{
2784 spin_lock(&unix_table_lock);
2785
2786 if (!*pos)
2787 return SEQ_START_TOKEN;
2788
2789 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2790 return NULL;
2791
2792 return unix_next_socket(seq, NULL, pos);
2793}
2794
2795static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2796{
2797 ++*pos;
2798 return unix_next_socket(seq, v, pos);
2799}
2800
2801static void unix_seq_stop(struct seq_file *seq, void *v)
2802 __releases(unix_table_lock)
2803{
2804 spin_unlock(&unix_table_lock);
2805}
2806
2807static int unix_seq_show(struct seq_file *seq, void *v)
2808{
2809
2810 if (v == SEQ_START_TOKEN)
2811 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2812 "Inode Path\n");
2813 else {
2814 struct sock *s = v;
2815 struct unix_sock *u = unix_sk(s);
2816 unix_state_lock(s);
2817
2818 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2819 s,
2820 atomic_read(&s->sk_refcnt),
2821 0,
2822 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2823 s->sk_type,
2824 s->sk_socket ?
2825 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2826 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2827 sock_i_ino(s));
2828
2829 if (u->addr) {
2830 int i, len;
2831 seq_putc(seq, ' ');
2832
2833 i = 0;
2834 len = u->addr->len - sizeof(short);
2835 if (!UNIX_ABSTRACT(s))
2836 len--;
2837 else {
2838 seq_putc(seq, '@');
2839 i++;
2840 }
2841 for ( ; i < len; i++)
2842 seq_putc(seq, u->addr->name->sun_path[i]);
2843 }
2844 unix_state_unlock(s);
2845 seq_putc(seq, '\n');
2846 }
2847
2848 return 0;
2849}
2850
2851static const struct seq_operations unix_seq_ops = {
2852 .start = unix_seq_start,
2853 .next = unix_seq_next,
2854 .stop = unix_seq_stop,
2855 .show = unix_seq_show,
2856};
2857
2858static int unix_seq_open(struct inode *inode, struct file *file)
2859{
2860 return seq_open_net(inode, file, &unix_seq_ops,
2861 sizeof(struct seq_net_private));
2862}
2863
2864static const struct file_operations unix_seq_fops = {
2865 .owner = THIS_MODULE,
2866 .open = unix_seq_open,
2867 .read = seq_read,
2868 .llseek = seq_lseek,
2869 .release = seq_release_net,
2870};
2871
2872#endif
2873
2874static const struct net_proto_family unix_family_ops = {
2875 .family = PF_UNIX,
2876 .create = unix_create,
2877 .owner = THIS_MODULE,
2878};
2879
2880
2881static int __net_init unix_net_init(struct net *net)
2882{
2883 int error = -ENOMEM;
2884
2885 net->unx.sysctl_max_dgram_qlen = 10;
2886 if (unix_sysctl_register(net))
2887 goto out;
2888
2889#ifdef CONFIG_PROC_FS
2890 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2891 unix_sysctl_unregister(net);
2892 goto out;
2893 }
2894#endif
2895 error = 0;
2896out:
2897 return error;
2898}
2899
2900static void __net_exit unix_net_exit(struct net *net)
2901{
2902 unix_sysctl_unregister(net);
2903 remove_proc_entry("unix", net->proc_net);
2904}
2905
2906static struct pernet_operations unix_net_ops = {
2907 .init = unix_net_init,
2908 .exit = unix_net_exit,
2909};
2910
2911static int __init af_unix_init(void)
2912{
2913 int rc = -1;
2914
2915 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2916
2917 rc = proto_register(&unix_proto, 1);
2918 if (rc != 0) {
2919 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
2920 goto out;
2921 }
2922
2923 sock_register(&unix_family_ops);
2924 register_pernet_subsys(&unix_net_ops);
2925out:
2926 return rc;
2927}
2928
2929static void __exit af_unix_exit(void)
2930{
2931 sock_unregister(PF_UNIX);
2932 proto_unregister(&unix_proto);
2933 unregister_pernet_subsys(&unix_net_ops);
2934}
2935
2936/* Earlier than device_initcall() so that other drivers invoking
2937 request_module() don't end up in a loop when modprobe tries
2938 to use a UNIX socket. But later than subsys_initcall() because
2939 we depend on stuff initialised there */
2940fs_initcall(af_unix_init);
2941module_exit(af_unix_exit);
2942
2943MODULE_LICENSE("GPL");
2944MODULE_ALIAS_NETPROTO(PF_UNIX);
1/*
2 * NET4: Implementation of BSD Unix domain sockets.
3 *
4 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * Fixes:
12 * Linus Torvalds : Assorted bug cures.
13 * Niibe Yutaka : async I/O support.
14 * Carsten Paeth : PF_UNIX check, address fixes.
15 * Alan Cox : Limit size of allocated blocks.
16 * Alan Cox : Fixed the stupid socketpair bug.
17 * Alan Cox : BSD compatibility fine tuning.
18 * Alan Cox : Fixed a bug in connect when interrupted.
19 * Alan Cox : Sorted out a proper draft version of
20 * file descriptor passing hacked up from
21 * Mike Shaver's work.
22 * Marty Leisner : Fixes to fd passing
23 * Nick Nevin : recvmsg bugfix.
24 * Alan Cox : Started proper garbage collector
25 * Heiko EiBfeldt : Missing verify_area check
26 * Alan Cox : Started POSIXisms
27 * Andreas Schwab : Replace inode by dentry for proper
28 * reference counting
29 * Kirk Petersen : Made this a module
30 * Christoph Rohland : Elegant non-blocking accept/connect algorithm.
31 * Lots of bug fixes.
32 * Alexey Kuznetosv : Repaired (I hope) bugs introduces
33 * by above two patches.
34 * Andrea Arcangeli : If possible we block in connect(2)
35 * if the max backlog of the listen socket
36 * is been reached. This won't break
37 * old apps and it will avoid huge amount
38 * of socks hashed (this for unix_gc()
39 * performances reasons).
40 * Security fix that limits the max
41 * number of socks to 2*max_files and
42 * the number of skb queueable in the
43 * dgram receiver.
44 * Artur Skawina : Hash function optimizations
45 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
46 * Malcolm Beattie : Set peercred for socketpair
47 * Michal Ostrowski : Module initialization cleanup.
48 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT,
49 * the core infrastructure is doing that
50 * for all net proto families now (2.5.69+)
51 *
52 *
53 * Known differences from reference BSD that was tested:
54 *
55 * [TO FIX]
56 * ECONNREFUSED is not returned from one end of a connected() socket to the
57 * other the moment one end closes.
58 * fstat() doesn't return st_dev=0, and give the blksize as high water mark
59 * and a fake inode identifier (nor the BSD first socket fstat twice bug).
60 * [NOT TO FIX]
61 * accept() returns a path name even if the connecting socket has closed
62 * in the meantime (BSD loses the path and gives up).
63 * accept() returns 0 length path for an unbound connector. BSD returns 16
64 * and a null first byte in the path (but not for gethost/peername - BSD bug ??)
65 * socketpair(...SOCK_RAW..) doesn't panic the kernel.
66 * BSD af_unix apparently has connect forgetting to block properly.
67 * (need to check this with the POSIX spec in detail)
68 *
69 * Differences from 2.0.0-11-... (ANK)
70 * Bug fixes and improvements.
71 * - client shutdown killed server socket.
72 * - removed all useless cli/sti pairs.
73 *
74 * Semantic changes/extensions.
75 * - generic control message passing.
76 * - SCM_CREDENTIALS control message.
77 * - "Abstract" (not FS based) socket bindings.
78 * Abstract names are sequences of bytes (not zero terminated)
79 * started by 0, so that this name space does not intersect
80 * with BSD names.
81 */
82
83#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
84
85#include <linux/module.h>
86#include <linux/kernel.h>
87#include <linux/signal.h>
88#include <linux/sched/signal.h>
89#include <linux/errno.h>
90#include <linux/string.h>
91#include <linux/stat.h>
92#include <linux/dcache.h>
93#include <linux/namei.h>
94#include <linux/socket.h>
95#include <linux/un.h>
96#include <linux/fcntl.h>
97#include <linux/termios.h>
98#include <linux/sockios.h>
99#include <linux/net.h>
100#include <linux/in.h>
101#include <linux/fs.h>
102#include <linux/slab.h>
103#include <linux/uaccess.h>
104#include <linux/skbuff.h>
105#include <linux/netdevice.h>
106#include <net/net_namespace.h>
107#include <net/sock.h>
108#include <net/tcp_states.h>
109#include <net/af_unix.h>
110#include <linux/proc_fs.h>
111#include <linux/seq_file.h>
112#include <net/scm.h>
113#include <linux/init.h>
114#include <linux/poll.h>
115#include <linux/rtnetlink.h>
116#include <linux/mount.h>
117#include <net/checksum.h>
118#include <linux/security.h>
119#include <linux/freezer.h>
120#include <linux/file.h>
121
122struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
123EXPORT_SYMBOL_GPL(unix_socket_table);
124DEFINE_SPINLOCK(unix_table_lock);
125EXPORT_SYMBOL_GPL(unix_table_lock);
126static atomic_long_t unix_nr_socks;
127
128
129static struct hlist_head *unix_sockets_unbound(void *addr)
130{
131 unsigned long hash = (unsigned long)addr;
132
133 hash ^= hash >> 16;
134 hash ^= hash >> 8;
135 hash %= UNIX_HASH_SIZE;
136 return &unix_socket_table[UNIX_HASH_SIZE + hash];
137}
138
139#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
140
141#ifdef CONFIG_SECURITY_NETWORK
142static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
143{
144 UNIXCB(skb).secid = scm->secid;
145}
146
147static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
148{
149 scm->secid = UNIXCB(skb).secid;
150}
151
152static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
153{
154 return (scm->secid == UNIXCB(skb).secid);
155}
156#else
157static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
158{ }
159
160static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
161{ }
162
163static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
164{
165 return true;
166}
167#endif /* CONFIG_SECURITY_NETWORK */
168
169/*
170 * SMP locking strategy:
171 * hash table is protected with spinlock unix_table_lock
172 * each socket state is protected by separate spin lock.
173 */
174
175static inline unsigned int unix_hash_fold(__wsum n)
176{
177 unsigned int hash = (__force unsigned int)csum_fold(n);
178
179 hash ^= hash>>8;
180 return hash&(UNIX_HASH_SIZE-1);
181}
182
183#define unix_peer(sk) (unix_sk(sk)->peer)
184
185static inline int unix_our_peer(struct sock *sk, struct sock *osk)
186{
187 return unix_peer(osk) == sk;
188}
189
190static inline int unix_may_send(struct sock *sk, struct sock *osk)
191{
192 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
193}
194
195static inline int unix_recvq_full(struct sock const *sk)
196{
197 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
198}
199
200struct sock *unix_peer_get(struct sock *s)
201{
202 struct sock *peer;
203
204 unix_state_lock(s);
205 peer = unix_peer(s);
206 if (peer)
207 sock_hold(peer);
208 unix_state_unlock(s);
209 return peer;
210}
211EXPORT_SYMBOL_GPL(unix_peer_get);
212
213static inline void unix_release_addr(struct unix_address *addr)
214{
215 if (refcount_dec_and_test(&addr->refcnt))
216 kfree(addr);
217}
218
219/*
220 * Check unix socket name:
221 * - should be not zero length.
222 * - if started by not zero, should be NULL terminated (FS object)
223 * - if started by zero, it is abstract name.
224 */
225
226static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
227{
228 if (len <= sizeof(short) || len > sizeof(*sunaddr))
229 return -EINVAL;
230 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
231 return -EINVAL;
232 if (sunaddr->sun_path[0]) {
233 /*
234 * This may look like an off by one error but it is a bit more
235 * subtle. 108 is the longest valid AF_UNIX path for a binding.
236 * sun_path[108] doesn't as such exist. However in kernel space
237 * we are guaranteed that it is a valid memory location in our
238 * kernel address buffer.
239 */
240 ((char *)sunaddr)[len] = 0;
241 len = strlen(sunaddr->sun_path)+1+sizeof(short);
242 return len;
243 }
244
245 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
246 return len;
247}
248
249static void __unix_remove_socket(struct sock *sk)
250{
251 sk_del_node_init(sk);
252}
253
254static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
255{
256 WARN_ON(!sk_unhashed(sk));
257 sk_add_node(sk, list);
258}
259
260static inline void unix_remove_socket(struct sock *sk)
261{
262 spin_lock(&unix_table_lock);
263 __unix_remove_socket(sk);
264 spin_unlock(&unix_table_lock);
265}
266
267static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
268{
269 spin_lock(&unix_table_lock);
270 __unix_insert_socket(list, sk);
271 spin_unlock(&unix_table_lock);
272}
273
274static struct sock *__unix_find_socket_byname(struct net *net,
275 struct sockaddr_un *sunname,
276 int len, int type, unsigned int hash)
277{
278 struct sock *s;
279
280 sk_for_each(s, &unix_socket_table[hash ^ type]) {
281 struct unix_sock *u = unix_sk(s);
282
283 if (!net_eq(sock_net(s), net))
284 continue;
285
286 if (u->addr->len == len &&
287 !memcmp(u->addr->name, sunname, len))
288 goto found;
289 }
290 s = NULL;
291found:
292 return s;
293}
294
295static inline struct sock *unix_find_socket_byname(struct net *net,
296 struct sockaddr_un *sunname,
297 int len, int type,
298 unsigned int hash)
299{
300 struct sock *s;
301
302 spin_lock(&unix_table_lock);
303 s = __unix_find_socket_byname(net, sunname, len, type, hash);
304 if (s)
305 sock_hold(s);
306 spin_unlock(&unix_table_lock);
307 return s;
308}
309
310static struct sock *unix_find_socket_byinode(struct inode *i)
311{
312 struct sock *s;
313
314 spin_lock(&unix_table_lock);
315 sk_for_each(s,
316 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
317 struct dentry *dentry = unix_sk(s)->path.dentry;
318
319 if (dentry && d_backing_inode(dentry) == i) {
320 sock_hold(s);
321 goto found;
322 }
323 }
324 s = NULL;
325found:
326 spin_unlock(&unix_table_lock);
327 return s;
328}
329
330/* Support code for asymmetrically connected dgram sockets
331 *
332 * If a datagram socket is connected to a socket not itself connected
333 * to the first socket (eg, /dev/log), clients may only enqueue more
334 * messages if the present receive queue of the server socket is not
335 * "too large". This means there's a second writeability condition
336 * poll and sendmsg need to test. The dgram recv code will do a wake
337 * up on the peer_wait wait queue of a socket upon reception of a
338 * datagram which needs to be propagated to sleeping would-be writers
339 * since these might not have sent anything so far. This can't be
340 * accomplished via poll_wait because the lifetime of the server
341 * socket might be less than that of its clients if these break their
342 * association with it or if the server socket is closed while clients
343 * are still connected to it and there's no way to inform "a polling
344 * implementation" that it should let go of a certain wait queue
345 *
346 * In order to propagate a wake up, a wait_queue_entry_t of the client
347 * socket is enqueued on the peer_wait queue of the server socket
348 * whose wake function does a wake_up on the ordinary client socket
349 * wait queue. This connection is established whenever a write (or
350 * poll for write) hit the flow control condition and broken when the
351 * association to the server socket is dissolved or after a wake up
352 * was relayed.
353 */
354
355static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
356 void *key)
357{
358 struct unix_sock *u;
359 wait_queue_head_t *u_sleep;
360
361 u = container_of(q, struct unix_sock, peer_wake);
362
363 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
364 q);
365 u->peer_wake.private = NULL;
366
367 /* relaying can only happen while the wq still exists */
368 u_sleep = sk_sleep(&u->sk);
369 if (u_sleep)
370 wake_up_interruptible_poll(u_sleep, key_to_poll(key));
371
372 return 0;
373}
374
375static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
376{
377 struct unix_sock *u, *u_other;
378 int rc;
379
380 u = unix_sk(sk);
381 u_other = unix_sk(other);
382 rc = 0;
383 spin_lock(&u_other->peer_wait.lock);
384
385 if (!u->peer_wake.private) {
386 u->peer_wake.private = other;
387 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
388
389 rc = 1;
390 }
391
392 spin_unlock(&u_other->peer_wait.lock);
393 return rc;
394}
395
396static void unix_dgram_peer_wake_disconnect(struct sock *sk,
397 struct sock *other)
398{
399 struct unix_sock *u, *u_other;
400
401 u = unix_sk(sk);
402 u_other = unix_sk(other);
403 spin_lock(&u_other->peer_wait.lock);
404
405 if (u->peer_wake.private == other) {
406 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
407 u->peer_wake.private = NULL;
408 }
409
410 spin_unlock(&u_other->peer_wait.lock);
411}
412
413static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
414 struct sock *other)
415{
416 unix_dgram_peer_wake_disconnect(sk, other);
417 wake_up_interruptible_poll(sk_sleep(sk),
418 EPOLLOUT |
419 EPOLLWRNORM |
420 EPOLLWRBAND);
421}
422
423/* preconditions:
424 * - unix_peer(sk) == other
425 * - association is stable
426 */
427static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
428{
429 int connected;
430
431 connected = unix_dgram_peer_wake_connect(sk, other);
432
433 if (unix_recvq_full(other))
434 return 1;
435
436 if (connected)
437 unix_dgram_peer_wake_disconnect(sk, other);
438
439 return 0;
440}
441
442static int unix_writable(const struct sock *sk)
443{
444 return sk->sk_state != TCP_LISTEN &&
445 (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
446}
447
448static void unix_write_space(struct sock *sk)
449{
450 struct socket_wq *wq;
451
452 rcu_read_lock();
453 if (unix_writable(sk)) {
454 wq = rcu_dereference(sk->sk_wq);
455 if (skwq_has_sleeper(wq))
456 wake_up_interruptible_sync_poll(&wq->wait,
457 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
458 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
459 }
460 rcu_read_unlock();
461}
462
463/* When dgram socket disconnects (or changes its peer), we clear its receive
464 * queue of packets arrived from previous peer. First, it allows to do
465 * flow control based only on wmem_alloc; second, sk connected to peer
466 * may receive messages only from that peer. */
467static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
468{
469 if (!skb_queue_empty(&sk->sk_receive_queue)) {
470 skb_queue_purge(&sk->sk_receive_queue);
471 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
472
473 /* If one link of bidirectional dgram pipe is disconnected,
474 * we signal error. Messages are lost. Do not make this,
475 * when peer was not connected to us.
476 */
477 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
478 other->sk_err = ECONNRESET;
479 other->sk_error_report(other);
480 }
481 }
482}
483
484static void unix_sock_destructor(struct sock *sk)
485{
486 struct unix_sock *u = unix_sk(sk);
487
488 skb_queue_purge(&sk->sk_receive_queue);
489
490 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
491 WARN_ON(!sk_unhashed(sk));
492 WARN_ON(sk->sk_socket);
493 if (!sock_flag(sk, SOCK_DEAD)) {
494 pr_info("Attempt to release alive unix socket: %p\n", sk);
495 return;
496 }
497
498 if (u->addr)
499 unix_release_addr(u->addr);
500
501 atomic_long_dec(&unix_nr_socks);
502 local_bh_disable();
503 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
504 local_bh_enable();
505#ifdef UNIX_REFCNT_DEBUG
506 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
507 atomic_long_read(&unix_nr_socks));
508#endif
509}
510
511static void unix_release_sock(struct sock *sk, int embrion)
512{
513 struct unix_sock *u = unix_sk(sk);
514 struct path path;
515 struct sock *skpair;
516 struct sk_buff *skb;
517 int state;
518
519 unix_remove_socket(sk);
520
521 /* Clear state */
522 unix_state_lock(sk);
523 sock_orphan(sk);
524 sk->sk_shutdown = SHUTDOWN_MASK;
525 path = u->path;
526 u->path.dentry = NULL;
527 u->path.mnt = NULL;
528 state = sk->sk_state;
529 sk->sk_state = TCP_CLOSE;
530 unix_state_unlock(sk);
531
532 wake_up_interruptible_all(&u->peer_wait);
533
534 skpair = unix_peer(sk);
535
536 if (skpair != NULL) {
537 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
538 unix_state_lock(skpair);
539 /* No more writes */
540 skpair->sk_shutdown = SHUTDOWN_MASK;
541 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
542 skpair->sk_err = ECONNRESET;
543 unix_state_unlock(skpair);
544 skpair->sk_state_change(skpair);
545 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
546 }
547
548 unix_dgram_peer_wake_disconnect(sk, skpair);
549 sock_put(skpair); /* It may now die */
550 unix_peer(sk) = NULL;
551 }
552
553 /* Try to flush out this socket. Throw out buffers at least */
554
555 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
556 if (state == TCP_LISTEN)
557 unix_release_sock(skb->sk, 1);
558 /* passed fds are erased in the kfree_skb hook */
559 UNIXCB(skb).consumed = skb->len;
560 kfree_skb(skb);
561 }
562
563 if (path.dentry)
564 path_put(&path);
565
566 sock_put(sk);
567
568 /* ---- Socket is dead now and most probably destroyed ---- */
569
570 /*
571 * Fixme: BSD difference: In BSD all sockets connected to us get
572 * ECONNRESET and we die on the spot. In Linux we behave
573 * like files and pipes do and wait for the last
574 * dereference.
575 *
576 * Can't we simply set sock->err?
577 *
578 * What the above comment does talk about? --ANK(980817)
579 */
580
581 if (unix_tot_inflight)
582 unix_gc(); /* Garbage collect fds */
583}
584
585static void init_peercred(struct sock *sk)
586{
587 put_pid(sk->sk_peer_pid);
588 if (sk->sk_peer_cred)
589 put_cred(sk->sk_peer_cred);
590 sk->sk_peer_pid = get_pid(task_tgid(current));
591 sk->sk_peer_cred = get_current_cred();
592}
593
594static void copy_peercred(struct sock *sk, struct sock *peersk)
595{
596 put_pid(sk->sk_peer_pid);
597 if (sk->sk_peer_cred)
598 put_cred(sk->sk_peer_cred);
599 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
600 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
601}
602
603static int unix_listen(struct socket *sock, int backlog)
604{
605 int err;
606 struct sock *sk = sock->sk;
607 struct unix_sock *u = unix_sk(sk);
608 struct pid *old_pid = NULL;
609
610 err = -EOPNOTSUPP;
611 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
612 goto out; /* Only stream/seqpacket sockets accept */
613 err = -EINVAL;
614 if (!u->addr)
615 goto out; /* No listens on an unbound socket */
616 unix_state_lock(sk);
617 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
618 goto out_unlock;
619 if (backlog > sk->sk_max_ack_backlog)
620 wake_up_interruptible_all(&u->peer_wait);
621 sk->sk_max_ack_backlog = backlog;
622 sk->sk_state = TCP_LISTEN;
623 /* set credentials so connect can copy them */
624 init_peercred(sk);
625 err = 0;
626
627out_unlock:
628 unix_state_unlock(sk);
629 put_pid(old_pid);
630out:
631 return err;
632}
633
634static int unix_release(struct socket *);
635static int unix_bind(struct socket *, struct sockaddr *, int);
636static int unix_stream_connect(struct socket *, struct sockaddr *,
637 int addr_len, int flags);
638static int unix_socketpair(struct socket *, struct socket *);
639static int unix_accept(struct socket *, struct socket *, int, bool);
640static int unix_getname(struct socket *, struct sockaddr *, int);
641static __poll_t unix_poll(struct file *, struct socket *, poll_table *);
642static __poll_t unix_dgram_poll(struct file *, struct socket *,
643 poll_table *);
644static int unix_ioctl(struct socket *, unsigned int, unsigned long);
645static int unix_shutdown(struct socket *, int);
646static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
647static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
648static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
649 size_t size, int flags);
650static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
651 struct pipe_inode_info *, size_t size,
652 unsigned int flags);
653static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
654static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
655static int unix_dgram_connect(struct socket *, struct sockaddr *,
656 int, int);
657static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
658static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
659 int);
660
661static int unix_set_peek_off(struct sock *sk, int val)
662{
663 struct unix_sock *u = unix_sk(sk);
664
665 if (mutex_lock_interruptible(&u->iolock))
666 return -EINTR;
667
668 sk->sk_peek_off = val;
669 mutex_unlock(&u->iolock);
670
671 return 0;
672}
673
674
675static const struct proto_ops unix_stream_ops = {
676 .family = PF_UNIX,
677 .owner = THIS_MODULE,
678 .release = unix_release,
679 .bind = unix_bind,
680 .connect = unix_stream_connect,
681 .socketpair = unix_socketpair,
682 .accept = unix_accept,
683 .getname = unix_getname,
684 .poll = unix_poll,
685 .ioctl = unix_ioctl,
686 .listen = unix_listen,
687 .shutdown = unix_shutdown,
688 .setsockopt = sock_no_setsockopt,
689 .getsockopt = sock_no_getsockopt,
690 .sendmsg = unix_stream_sendmsg,
691 .recvmsg = unix_stream_recvmsg,
692 .mmap = sock_no_mmap,
693 .sendpage = unix_stream_sendpage,
694 .splice_read = unix_stream_splice_read,
695 .set_peek_off = unix_set_peek_off,
696};
697
698static const struct proto_ops unix_dgram_ops = {
699 .family = PF_UNIX,
700 .owner = THIS_MODULE,
701 .release = unix_release,
702 .bind = unix_bind,
703 .connect = unix_dgram_connect,
704 .socketpair = unix_socketpair,
705 .accept = sock_no_accept,
706 .getname = unix_getname,
707 .poll = unix_dgram_poll,
708 .ioctl = unix_ioctl,
709 .listen = sock_no_listen,
710 .shutdown = unix_shutdown,
711 .setsockopt = sock_no_setsockopt,
712 .getsockopt = sock_no_getsockopt,
713 .sendmsg = unix_dgram_sendmsg,
714 .recvmsg = unix_dgram_recvmsg,
715 .mmap = sock_no_mmap,
716 .sendpage = sock_no_sendpage,
717 .set_peek_off = unix_set_peek_off,
718};
719
720static const struct proto_ops unix_seqpacket_ops = {
721 .family = PF_UNIX,
722 .owner = THIS_MODULE,
723 .release = unix_release,
724 .bind = unix_bind,
725 .connect = unix_stream_connect,
726 .socketpair = unix_socketpair,
727 .accept = unix_accept,
728 .getname = unix_getname,
729 .poll = unix_dgram_poll,
730 .ioctl = unix_ioctl,
731 .listen = unix_listen,
732 .shutdown = unix_shutdown,
733 .setsockopt = sock_no_setsockopt,
734 .getsockopt = sock_no_getsockopt,
735 .sendmsg = unix_seqpacket_sendmsg,
736 .recvmsg = unix_seqpacket_recvmsg,
737 .mmap = sock_no_mmap,
738 .sendpage = sock_no_sendpage,
739 .set_peek_off = unix_set_peek_off,
740};
741
742static struct proto unix_proto = {
743 .name = "UNIX",
744 .owner = THIS_MODULE,
745 .obj_size = sizeof(struct unix_sock),
746};
747
748static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
749{
750 struct sock *sk = NULL;
751 struct unix_sock *u;
752
753 atomic_long_inc(&unix_nr_socks);
754 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
755 goto out;
756
757 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
758 if (!sk)
759 goto out;
760
761 sock_init_data(sock, sk);
762
763 sk->sk_allocation = GFP_KERNEL_ACCOUNT;
764 sk->sk_write_space = unix_write_space;
765 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
766 sk->sk_destruct = unix_sock_destructor;
767 u = unix_sk(sk);
768 u->path.dentry = NULL;
769 u->path.mnt = NULL;
770 spin_lock_init(&u->lock);
771 atomic_long_set(&u->inflight, 0);
772 INIT_LIST_HEAD(&u->link);
773 mutex_init(&u->iolock); /* single task reading lock */
774 mutex_init(&u->bindlock); /* single task binding lock */
775 init_waitqueue_head(&u->peer_wait);
776 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
777 unix_insert_socket(unix_sockets_unbound(sk), sk);
778out:
779 if (sk == NULL)
780 atomic_long_dec(&unix_nr_socks);
781 else {
782 local_bh_disable();
783 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
784 local_bh_enable();
785 }
786 return sk;
787}
788
789static int unix_create(struct net *net, struct socket *sock, int protocol,
790 int kern)
791{
792 if (protocol && protocol != PF_UNIX)
793 return -EPROTONOSUPPORT;
794
795 sock->state = SS_UNCONNECTED;
796
797 switch (sock->type) {
798 case SOCK_STREAM:
799 sock->ops = &unix_stream_ops;
800 break;
801 /*
802 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
803 * nothing uses it.
804 */
805 case SOCK_RAW:
806 sock->type = SOCK_DGRAM;
807 /* fall through */
808 case SOCK_DGRAM:
809 sock->ops = &unix_dgram_ops;
810 break;
811 case SOCK_SEQPACKET:
812 sock->ops = &unix_seqpacket_ops;
813 break;
814 default:
815 return -ESOCKTNOSUPPORT;
816 }
817
818 return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
819}
820
821static int unix_release(struct socket *sock)
822{
823 struct sock *sk = sock->sk;
824
825 if (!sk)
826 return 0;
827
828 unix_release_sock(sk, 0);
829 sock->sk = NULL;
830
831 return 0;
832}
833
834static int unix_autobind(struct socket *sock)
835{
836 struct sock *sk = sock->sk;
837 struct net *net = sock_net(sk);
838 struct unix_sock *u = unix_sk(sk);
839 static u32 ordernum = 1;
840 struct unix_address *addr;
841 int err;
842 unsigned int retries = 0;
843
844 err = mutex_lock_interruptible(&u->bindlock);
845 if (err)
846 return err;
847
848 err = 0;
849 if (u->addr)
850 goto out;
851
852 err = -ENOMEM;
853 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
854 if (!addr)
855 goto out;
856
857 addr->name->sun_family = AF_UNIX;
858 refcount_set(&addr->refcnt, 1);
859
860retry:
861 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
862 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
863
864 spin_lock(&unix_table_lock);
865 ordernum = (ordernum+1)&0xFFFFF;
866
867 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
868 addr->hash)) {
869 spin_unlock(&unix_table_lock);
870 /*
871 * __unix_find_socket_byname() may take long time if many names
872 * are already in use.
873 */
874 cond_resched();
875 /* Give up if all names seems to be in use. */
876 if (retries++ == 0xFFFFF) {
877 err = -ENOSPC;
878 kfree(addr);
879 goto out;
880 }
881 goto retry;
882 }
883 addr->hash ^= sk->sk_type;
884
885 __unix_remove_socket(sk);
886 u->addr = addr;
887 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
888 spin_unlock(&unix_table_lock);
889 err = 0;
890
891out: mutex_unlock(&u->bindlock);
892 return err;
893}
894
895static struct sock *unix_find_other(struct net *net,
896 struct sockaddr_un *sunname, int len,
897 int type, unsigned int hash, int *error)
898{
899 struct sock *u;
900 struct path path;
901 int err = 0;
902
903 if (sunname->sun_path[0]) {
904 struct inode *inode;
905 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
906 if (err)
907 goto fail;
908 inode = d_backing_inode(path.dentry);
909 err = inode_permission(inode, MAY_WRITE);
910 if (err)
911 goto put_fail;
912
913 err = -ECONNREFUSED;
914 if (!S_ISSOCK(inode->i_mode))
915 goto put_fail;
916 u = unix_find_socket_byinode(inode);
917 if (!u)
918 goto put_fail;
919
920 if (u->sk_type == type)
921 touch_atime(&path);
922
923 path_put(&path);
924
925 err = -EPROTOTYPE;
926 if (u->sk_type != type) {
927 sock_put(u);
928 goto fail;
929 }
930 } else {
931 err = -ECONNREFUSED;
932 u = unix_find_socket_byname(net, sunname, len, type, hash);
933 if (u) {
934 struct dentry *dentry;
935 dentry = unix_sk(u)->path.dentry;
936 if (dentry)
937 touch_atime(&unix_sk(u)->path);
938 } else
939 goto fail;
940 }
941 return u;
942
943put_fail:
944 path_put(&path);
945fail:
946 *error = err;
947 return NULL;
948}
949
950static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
951{
952 struct dentry *dentry;
953 struct path path;
954 int err = 0;
955 /*
956 * Get the parent directory, calculate the hash for last
957 * component.
958 */
959 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
960 err = PTR_ERR(dentry);
961 if (IS_ERR(dentry))
962 return err;
963
964 /*
965 * All right, let's create it.
966 */
967 err = security_path_mknod(&path, dentry, mode, 0);
968 if (!err) {
969 err = vfs_mknod(d_inode(path.dentry), dentry, mode, 0);
970 if (!err) {
971 res->mnt = mntget(path.mnt);
972 res->dentry = dget(dentry);
973 }
974 }
975 done_path_create(&path, dentry);
976 return err;
977}
978
979static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
980{
981 struct sock *sk = sock->sk;
982 struct net *net = sock_net(sk);
983 struct unix_sock *u = unix_sk(sk);
984 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
985 char *sun_path = sunaddr->sun_path;
986 int err;
987 unsigned int hash;
988 struct unix_address *addr;
989 struct hlist_head *list;
990 struct path path = { };
991
992 err = -EINVAL;
993 if (addr_len < offsetofend(struct sockaddr_un, sun_family) ||
994 sunaddr->sun_family != AF_UNIX)
995 goto out;
996
997 if (addr_len == sizeof(short)) {
998 err = unix_autobind(sock);
999 goto out;
1000 }
1001
1002 err = unix_mkname(sunaddr, addr_len, &hash);
1003 if (err < 0)
1004 goto out;
1005 addr_len = err;
1006
1007 if (sun_path[0]) {
1008 umode_t mode = S_IFSOCK |
1009 (SOCK_INODE(sock)->i_mode & ~current_umask());
1010 err = unix_mknod(sun_path, mode, &path);
1011 if (err) {
1012 if (err == -EEXIST)
1013 err = -EADDRINUSE;
1014 goto out;
1015 }
1016 }
1017
1018 err = mutex_lock_interruptible(&u->bindlock);
1019 if (err)
1020 goto out_put;
1021
1022 err = -EINVAL;
1023 if (u->addr)
1024 goto out_up;
1025
1026 err = -ENOMEM;
1027 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
1028 if (!addr)
1029 goto out_up;
1030
1031 memcpy(addr->name, sunaddr, addr_len);
1032 addr->len = addr_len;
1033 addr->hash = hash ^ sk->sk_type;
1034 refcount_set(&addr->refcnt, 1);
1035
1036 if (sun_path[0]) {
1037 addr->hash = UNIX_HASH_SIZE;
1038 hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE - 1);
1039 spin_lock(&unix_table_lock);
1040 u->path = path;
1041 list = &unix_socket_table[hash];
1042 } else {
1043 spin_lock(&unix_table_lock);
1044 err = -EADDRINUSE;
1045 if (__unix_find_socket_byname(net, sunaddr, addr_len,
1046 sk->sk_type, hash)) {
1047 unix_release_addr(addr);
1048 goto out_unlock;
1049 }
1050
1051 list = &unix_socket_table[addr->hash];
1052 }
1053
1054 err = 0;
1055 __unix_remove_socket(sk);
1056 u->addr = addr;
1057 __unix_insert_socket(list, sk);
1058
1059out_unlock:
1060 spin_unlock(&unix_table_lock);
1061out_up:
1062 mutex_unlock(&u->bindlock);
1063out_put:
1064 if (err)
1065 path_put(&path);
1066out:
1067 return err;
1068}
1069
1070static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1071{
1072 if (unlikely(sk1 == sk2) || !sk2) {
1073 unix_state_lock(sk1);
1074 return;
1075 }
1076 if (sk1 < sk2) {
1077 unix_state_lock(sk1);
1078 unix_state_lock_nested(sk2);
1079 } else {
1080 unix_state_lock(sk2);
1081 unix_state_lock_nested(sk1);
1082 }
1083}
1084
1085static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1086{
1087 if (unlikely(sk1 == sk2) || !sk2) {
1088 unix_state_unlock(sk1);
1089 return;
1090 }
1091 unix_state_unlock(sk1);
1092 unix_state_unlock(sk2);
1093}
1094
1095static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1096 int alen, int flags)
1097{
1098 struct sock *sk = sock->sk;
1099 struct net *net = sock_net(sk);
1100 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1101 struct sock *other;
1102 unsigned int hash;
1103 int err;
1104
1105 err = -EINVAL;
1106 if (alen < offsetofend(struct sockaddr, sa_family))
1107 goto out;
1108
1109 if (addr->sa_family != AF_UNSPEC) {
1110 err = unix_mkname(sunaddr, alen, &hash);
1111 if (err < 0)
1112 goto out;
1113 alen = err;
1114
1115 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1116 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1117 goto out;
1118
1119restart:
1120 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1121 if (!other)
1122 goto out;
1123
1124 unix_state_double_lock(sk, other);
1125
1126 /* Apparently VFS overslept socket death. Retry. */
1127 if (sock_flag(other, SOCK_DEAD)) {
1128 unix_state_double_unlock(sk, other);
1129 sock_put(other);
1130 goto restart;
1131 }
1132
1133 err = -EPERM;
1134 if (!unix_may_send(sk, other))
1135 goto out_unlock;
1136
1137 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1138 if (err)
1139 goto out_unlock;
1140
1141 } else {
1142 /*
1143 * 1003.1g breaking connected state with AF_UNSPEC
1144 */
1145 other = NULL;
1146 unix_state_double_lock(sk, other);
1147 }
1148
1149 /*
1150 * If it was connected, reconnect.
1151 */
1152 if (unix_peer(sk)) {
1153 struct sock *old_peer = unix_peer(sk);
1154 unix_peer(sk) = other;
1155 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1156
1157 unix_state_double_unlock(sk, other);
1158
1159 if (other != old_peer)
1160 unix_dgram_disconnected(sk, old_peer);
1161 sock_put(old_peer);
1162 } else {
1163 unix_peer(sk) = other;
1164 unix_state_double_unlock(sk, other);
1165 }
1166 return 0;
1167
1168out_unlock:
1169 unix_state_double_unlock(sk, other);
1170 sock_put(other);
1171out:
1172 return err;
1173}
1174
1175static long unix_wait_for_peer(struct sock *other, long timeo)
1176{
1177 struct unix_sock *u = unix_sk(other);
1178 int sched;
1179 DEFINE_WAIT(wait);
1180
1181 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1182
1183 sched = !sock_flag(other, SOCK_DEAD) &&
1184 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1185 unix_recvq_full(other);
1186
1187 unix_state_unlock(other);
1188
1189 if (sched)
1190 timeo = schedule_timeout(timeo);
1191
1192 finish_wait(&u->peer_wait, &wait);
1193 return timeo;
1194}
1195
1196static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1197 int addr_len, int flags)
1198{
1199 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1200 struct sock *sk = sock->sk;
1201 struct net *net = sock_net(sk);
1202 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1203 struct sock *newsk = NULL;
1204 struct sock *other = NULL;
1205 struct sk_buff *skb = NULL;
1206 unsigned int hash;
1207 int st;
1208 int err;
1209 long timeo;
1210
1211 err = unix_mkname(sunaddr, addr_len, &hash);
1212 if (err < 0)
1213 goto out;
1214 addr_len = err;
1215
1216 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1217 (err = unix_autobind(sock)) != 0)
1218 goto out;
1219
1220 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1221
1222 /* First of all allocate resources.
1223 If we will make it after state is locked,
1224 we will have to recheck all again in any case.
1225 */
1226
1227 err = -ENOMEM;
1228
1229 /* create new sock for complete connection */
1230 newsk = unix_create1(sock_net(sk), NULL, 0);
1231 if (newsk == NULL)
1232 goto out;
1233
1234 /* Allocate skb for sending to listening sock */
1235 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1236 if (skb == NULL)
1237 goto out;
1238
1239restart:
1240 /* Find listening sock. */
1241 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1242 if (!other)
1243 goto out;
1244
1245 /* Latch state of peer */
1246 unix_state_lock(other);
1247
1248 /* Apparently VFS overslept socket death. Retry. */
1249 if (sock_flag(other, SOCK_DEAD)) {
1250 unix_state_unlock(other);
1251 sock_put(other);
1252 goto restart;
1253 }
1254
1255 err = -ECONNREFUSED;
1256 if (other->sk_state != TCP_LISTEN)
1257 goto out_unlock;
1258 if (other->sk_shutdown & RCV_SHUTDOWN)
1259 goto out_unlock;
1260
1261 if (unix_recvq_full(other)) {
1262 err = -EAGAIN;
1263 if (!timeo)
1264 goto out_unlock;
1265
1266 timeo = unix_wait_for_peer(other, timeo);
1267
1268 err = sock_intr_errno(timeo);
1269 if (signal_pending(current))
1270 goto out;
1271 sock_put(other);
1272 goto restart;
1273 }
1274
1275 /* Latch our state.
1276
1277 It is tricky place. We need to grab our state lock and cannot
1278 drop lock on peer. It is dangerous because deadlock is
1279 possible. Connect to self case and simultaneous
1280 attempt to connect are eliminated by checking socket
1281 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1282 check this before attempt to grab lock.
1283
1284 Well, and we have to recheck the state after socket locked.
1285 */
1286 st = sk->sk_state;
1287
1288 switch (st) {
1289 case TCP_CLOSE:
1290 /* This is ok... continue with connect */
1291 break;
1292 case TCP_ESTABLISHED:
1293 /* Socket is already connected */
1294 err = -EISCONN;
1295 goto out_unlock;
1296 default:
1297 err = -EINVAL;
1298 goto out_unlock;
1299 }
1300
1301 unix_state_lock_nested(sk);
1302
1303 if (sk->sk_state != st) {
1304 unix_state_unlock(sk);
1305 unix_state_unlock(other);
1306 sock_put(other);
1307 goto restart;
1308 }
1309
1310 err = security_unix_stream_connect(sk, other, newsk);
1311 if (err) {
1312 unix_state_unlock(sk);
1313 goto out_unlock;
1314 }
1315
1316 /* The way is open! Fastly set all the necessary fields... */
1317
1318 sock_hold(sk);
1319 unix_peer(newsk) = sk;
1320 newsk->sk_state = TCP_ESTABLISHED;
1321 newsk->sk_type = sk->sk_type;
1322 init_peercred(newsk);
1323 newu = unix_sk(newsk);
1324 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1325 otheru = unix_sk(other);
1326
1327 /* copy address information from listening to new sock*/
1328 if (otheru->addr) {
1329 refcount_inc(&otheru->addr->refcnt);
1330 newu->addr = otheru->addr;
1331 }
1332 if (otheru->path.dentry) {
1333 path_get(&otheru->path);
1334 newu->path = otheru->path;
1335 }
1336
1337 /* Set credentials */
1338 copy_peercred(sk, other);
1339
1340 sock->state = SS_CONNECTED;
1341 sk->sk_state = TCP_ESTABLISHED;
1342 sock_hold(newsk);
1343
1344 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1345 unix_peer(sk) = newsk;
1346
1347 unix_state_unlock(sk);
1348
1349 /* take ten and and send info to listening sock */
1350 spin_lock(&other->sk_receive_queue.lock);
1351 __skb_queue_tail(&other->sk_receive_queue, skb);
1352 spin_unlock(&other->sk_receive_queue.lock);
1353 unix_state_unlock(other);
1354 other->sk_data_ready(other);
1355 sock_put(other);
1356 return 0;
1357
1358out_unlock:
1359 if (other)
1360 unix_state_unlock(other);
1361
1362out:
1363 kfree_skb(skb);
1364 if (newsk)
1365 unix_release_sock(newsk, 0);
1366 if (other)
1367 sock_put(other);
1368 return err;
1369}
1370
1371static int unix_socketpair(struct socket *socka, struct socket *sockb)
1372{
1373 struct sock *ska = socka->sk, *skb = sockb->sk;
1374
1375 /* Join our sockets back to back */
1376 sock_hold(ska);
1377 sock_hold(skb);
1378 unix_peer(ska) = skb;
1379 unix_peer(skb) = ska;
1380 init_peercred(ska);
1381 init_peercred(skb);
1382
1383 if (ska->sk_type != SOCK_DGRAM) {
1384 ska->sk_state = TCP_ESTABLISHED;
1385 skb->sk_state = TCP_ESTABLISHED;
1386 socka->state = SS_CONNECTED;
1387 sockb->state = SS_CONNECTED;
1388 }
1389 return 0;
1390}
1391
1392static void unix_sock_inherit_flags(const struct socket *old,
1393 struct socket *new)
1394{
1395 if (test_bit(SOCK_PASSCRED, &old->flags))
1396 set_bit(SOCK_PASSCRED, &new->flags);
1397 if (test_bit(SOCK_PASSSEC, &old->flags))
1398 set_bit(SOCK_PASSSEC, &new->flags);
1399}
1400
1401static int unix_accept(struct socket *sock, struct socket *newsock, int flags,
1402 bool kern)
1403{
1404 struct sock *sk = sock->sk;
1405 struct sock *tsk;
1406 struct sk_buff *skb;
1407 int err;
1408
1409 err = -EOPNOTSUPP;
1410 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1411 goto out;
1412
1413 err = -EINVAL;
1414 if (sk->sk_state != TCP_LISTEN)
1415 goto out;
1416
1417 /* If socket state is TCP_LISTEN it cannot change (for now...),
1418 * so that no locks are necessary.
1419 */
1420
1421 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1422 if (!skb) {
1423 /* This means receive shutdown. */
1424 if (err == 0)
1425 err = -EINVAL;
1426 goto out;
1427 }
1428
1429 tsk = skb->sk;
1430 skb_free_datagram(sk, skb);
1431 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1432
1433 /* attach accepted sock to socket */
1434 unix_state_lock(tsk);
1435 newsock->state = SS_CONNECTED;
1436 unix_sock_inherit_flags(sock, newsock);
1437 sock_graft(tsk, newsock);
1438 unix_state_unlock(tsk);
1439 return 0;
1440
1441out:
1442 return err;
1443}
1444
1445
1446static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1447{
1448 struct sock *sk = sock->sk;
1449 struct unix_sock *u;
1450 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1451 int err = 0;
1452
1453 if (peer) {
1454 sk = unix_peer_get(sk);
1455
1456 err = -ENOTCONN;
1457 if (!sk)
1458 goto out;
1459 err = 0;
1460 } else {
1461 sock_hold(sk);
1462 }
1463
1464 u = unix_sk(sk);
1465 unix_state_lock(sk);
1466 if (!u->addr) {
1467 sunaddr->sun_family = AF_UNIX;
1468 sunaddr->sun_path[0] = 0;
1469 err = sizeof(short);
1470 } else {
1471 struct unix_address *addr = u->addr;
1472
1473 err = addr->len;
1474 memcpy(sunaddr, addr->name, addr->len);
1475 }
1476 unix_state_unlock(sk);
1477 sock_put(sk);
1478out:
1479 return err;
1480}
1481
1482static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1483{
1484 int i;
1485
1486 scm->fp = UNIXCB(skb).fp;
1487 UNIXCB(skb).fp = NULL;
1488
1489 for (i = scm->fp->count-1; i >= 0; i--)
1490 unix_notinflight(scm->fp->user, scm->fp->fp[i]);
1491}
1492
1493static void unix_destruct_scm(struct sk_buff *skb)
1494{
1495 struct scm_cookie scm;
1496 memset(&scm, 0, sizeof(scm));
1497 scm.pid = UNIXCB(skb).pid;
1498 if (UNIXCB(skb).fp)
1499 unix_detach_fds(&scm, skb);
1500
1501 /* Alas, it calls VFS */
1502 /* So fscking what? fput() had been SMP-safe since the last Summer */
1503 scm_destroy(&scm);
1504 sock_wfree(skb);
1505}
1506
1507/*
1508 * The "user->unix_inflight" variable is protected by the garbage
1509 * collection lock, and we just read it locklessly here. If you go
1510 * over the limit, there might be a tiny race in actually noticing
1511 * it across threads. Tough.
1512 */
1513static inline bool too_many_unix_fds(struct task_struct *p)
1514{
1515 struct user_struct *user = current_user();
1516
1517 if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
1518 return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1519 return false;
1520}
1521
1522static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1523{
1524 int i;
1525
1526 if (too_many_unix_fds(current))
1527 return -ETOOMANYREFS;
1528
1529 /*
1530 * Need to duplicate file references for the sake of garbage
1531 * collection. Otherwise a socket in the fps might become a
1532 * candidate for GC while the skb is not yet queued.
1533 */
1534 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1535 if (!UNIXCB(skb).fp)
1536 return -ENOMEM;
1537
1538 for (i = scm->fp->count - 1; i >= 0; i--)
1539 unix_inflight(scm->fp->user, scm->fp->fp[i]);
1540 return 0;
1541}
1542
1543static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1544{
1545 int err = 0;
1546
1547 UNIXCB(skb).pid = get_pid(scm->pid);
1548 UNIXCB(skb).uid = scm->creds.uid;
1549 UNIXCB(skb).gid = scm->creds.gid;
1550 UNIXCB(skb).fp = NULL;
1551 unix_get_secdata(scm, skb);
1552 if (scm->fp && send_fds)
1553 err = unix_attach_fds(scm, skb);
1554
1555 skb->destructor = unix_destruct_scm;
1556 return err;
1557}
1558
1559static bool unix_passcred_enabled(const struct socket *sock,
1560 const struct sock *other)
1561{
1562 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1563 !other->sk_socket ||
1564 test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1565}
1566
1567/*
1568 * Some apps rely on write() giving SCM_CREDENTIALS
1569 * We include credentials if source or destination socket
1570 * asserted SOCK_PASSCRED.
1571 */
1572static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1573 const struct sock *other)
1574{
1575 if (UNIXCB(skb).pid)
1576 return;
1577 if (unix_passcred_enabled(sock, other)) {
1578 UNIXCB(skb).pid = get_pid(task_tgid(current));
1579 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1580 }
1581}
1582
1583static int maybe_init_creds(struct scm_cookie *scm,
1584 struct socket *socket,
1585 const struct sock *other)
1586{
1587 int err;
1588 struct msghdr msg = { .msg_controllen = 0 };
1589
1590 err = scm_send(socket, &msg, scm, false);
1591 if (err)
1592 return err;
1593
1594 if (unix_passcred_enabled(socket, other)) {
1595 scm->pid = get_pid(task_tgid(current));
1596 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1597 }
1598 return err;
1599}
1600
1601static bool unix_skb_scm_eq(struct sk_buff *skb,
1602 struct scm_cookie *scm)
1603{
1604 const struct unix_skb_parms *u = &UNIXCB(skb);
1605
1606 return u->pid == scm->pid &&
1607 uid_eq(u->uid, scm->creds.uid) &&
1608 gid_eq(u->gid, scm->creds.gid) &&
1609 unix_secdata_eq(scm, skb);
1610}
1611
1612/*
1613 * Send AF_UNIX data.
1614 */
1615
1616static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1617 size_t len)
1618{
1619 struct sock *sk = sock->sk;
1620 struct net *net = sock_net(sk);
1621 struct unix_sock *u = unix_sk(sk);
1622 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1623 struct sock *other = NULL;
1624 int namelen = 0; /* fake GCC */
1625 int err;
1626 unsigned int hash;
1627 struct sk_buff *skb;
1628 long timeo;
1629 struct scm_cookie scm;
1630 int data_len = 0;
1631 int sk_locked;
1632
1633 wait_for_unix_gc();
1634 err = scm_send(sock, msg, &scm, false);
1635 if (err < 0)
1636 return err;
1637
1638 err = -EOPNOTSUPP;
1639 if (msg->msg_flags&MSG_OOB)
1640 goto out;
1641
1642 if (msg->msg_namelen) {
1643 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1644 if (err < 0)
1645 goto out;
1646 namelen = err;
1647 } else {
1648 sunaddr = NULL;
1649 err = -ENOTCONN;
1650 other = unix_peer_get(sk);
1651 if (!other)
1652 goto out;
1653 }
1654
1655 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1656 && (err = unix_autobind(sock)) != 0)
1657 goto out;
1658
1659 err = -EMSGSIZE;
1660 if (len > sk->sk_sndbuf - 32)
1661 goto out;
1662
1663 if (len > SKB_MAX_ALLOC) {
1664 data_len = min_t(size_t,
1665 len - SKB_MAX_ALLOC,
1666 MAX_SKB_FRAGS * PAGE_SIZE);
1667 data_len = PAGE_ALIGN(data_len);
1668
1669 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1670 }
1671
1672 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1673 msg->msg_flags & MSG_DONTWAIT, &err,
1674 PAGE_ALLOC_COSTLY_ORDER);
1675 if (skb == NULL)
1676 goto out;
1677
1678 err = unix_scm_to_skb(&scm, skb, true);
1679 if (err < 0)
1680 goto out_free;
1681
1682 skb_put(skb, len - data_len);
1683 skb->data_len = data_len;
1684 skb->len = len;
1685 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1686 if (err)
1687 goto out_free;
1688
1689 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1690
1691restart:
1692 if (!other) {
1693 err = -ECONNRESET;
1694 if (sunaddr == NULL)
1695 goto out_free;
1696
1697 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1698 hash, &err);
1699 if (other == NULL)
1700 goto out_free;
1701 }
1702
1703 if (sk_filter(other, skb) < 0) {
1704 /* Toss the packet but do not return any error to the sender */
1705 err = len;
1706 goto out_free;
1707 }
1708
1709 sk_locked = 0;
1710 unix_state_lock(other);
1711restart_locked:
1712 err = -EPERM;
1713 if (!unix_may_send(sk, other))
1714 goto out_unlock;
1715
1716 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1717 /*
1718 * Check with 1003.1g - what should
1719 * datagram error
1720 */
1721 unix_state_unlock(other);
1722 sock_put(other);
1723
1724 if (!sk_locked)
1725 unix_state_lock(sk);
1726
1727 err = 0;
1728 if (unix_peer(sk) == other) {
1729 unix_peer(sk) = NULL;
1730 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1731
1732 unix_state_unlock(sk);
1733
1734 unix_dgram_disconnected(sk, other);
1735 sock_put(other);
1736 err = -ECONNREFUSED;
1737 } else {
1738 unix_state_unlock(sk);
1739 }
1740
1741 other = NULL;
1742 if (err)
1743 goto out_free;
1744 goto restart;
1745 }
1746
1747 err = -EPIPE;
1748 if (other->sk_shutdown & RCV_SHUTDOWN)
1749 goto out_unlock;
1750
1751 if (sk->sk_type != SOCK_SEQPACKET) {
1752 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1753 if (err)
1754 goto out_unlock;
1755 }
1756
1757 /* other == sk && unix_peer(other) != sk if
1758 * - unix_peer(sk) == NULL, destination address bound to sk
1759 * - unix_peer(sk) == sk by time of get but disconnected before lock
1760 */
1761 if (other != sk &&
1762 unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1763 if (timeo) {
1764 timeo = unix_wait_for_peer(other, timeo);
1765
1766 err = sock_intr_errno(timeo);
1767 if (signal_pending(current))
1768 goto out_free;
1769
1770 goto restart;
1771 }
1772
1773 if (!sk_locked) {
1774 unix_state_unlock(other);
1775 unix_state_double_lock(sk, other);
1776 }
1777
1778 if (unix_peer(sk) != other ||
1779 unix_dgram_peer_wake_me(sk, other)) {
1780 err = -EAGAIN;
1781 sk_locked = 1;
1782 goto out_unlock;
1783 }
1784
1785 if (!sk_locked) {
1786 sk_locked = 1;
1787 goto restart_locked;
1788 }
1789 }
1790
1791 if (unlikely(sk_locked))
1792 unix_state_unlock(sk);
1793
1794 if (sock_flag(other, SOCK_RCVTSTAMP))
1795 __net_timestamp(skb);
1796 maybe_add_creds(skb, sock, other);
1797 skb_queue_tail(&other->sk_receive_queue, skb);
1798 unix_state_unlock(other);
1799 other->sk_data_ready(other);
1800 sock_put(other);
1801 scm_destroy(&scm);
1802 return len;
1803
1804out_unlock:
1805 if (sk_locked)
1806 unix_state_unlock(sk);
1807 unix_state_unlock(other);
1808out_free:
1809 kfree_skb(skb);
1810out:
1811 if (other)
1812 sock_put(other);
1813 scm_destroy(&scm);
1814 return err;
1815}
1816
1817/* We use paged skbs for stream sockets, and limit occupancy to 32768
1818 * bytes, and a minimum of a full page.
1819 */
1820#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1821
1822static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
1823 size_t len)
1824{
1825 struct sock *sk = sock->sk;
1826 struct sock *other = NULL;
1827 int err, size;
1828 struct sk_buff *skb;
1829 int sent = 0;
1830 struct scm_cookie scm;
1831 bool fds_sent = false;
1832 int data_len;
1833
1834 wait_for_unix_gc();
1835 err = scm_send(sock, msg, &scm, false);
1836 if (err < 0)
1837 return err;
1838
1839 err = -EOPNOTSUPP;
1840 if (msg->msg_flags&MSG_OOB)
1841 goto out_err;
1842
1843 if (msg->msg_namelen) {
1844 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1845 goto out_err;
1846 } else {
1847 err = -ENOTCONN;
1848 other = unix_peer(sk);
1849 if (!other)
1850 goto out_err;
1851 }
1852
1853 if (sk->sk_shutdown & SEND_SHUTDOWN)
1854 goto pipe_err;
1855
1856 while (sent < len) {
1857 size = len - sent;
1858
1859 /* Keep two messages in the pipe so it schedules better */
1860 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1861
1862 /* allow fallback to order-0 allocations */
1863 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1864
1865 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1866
1867 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
1868
1869 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1870 msg->msg_flags & MSG_DONTWAIT, &err,
1871 get_order(UNIX_SKB_FRAGS_SZ));
1872 if (!skb)
1873 goto out_err;
1874
1875 /* Only send the fds in the first buffer */
1876 err = unix_scm_to_skb(&scm, skb, !fds_sent);
1877 if (err < 0) {
1878 kfree_skb(skb);
1879 goto out_err;
1880 }
1881 fds_sent = true;
1882
1883 skb_put(skb, size - data_len);
1884 skb->data_len = data_len;
1885 skb->len = size;
1886 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
1887 if (err) {
1888 kfree_skb(skb);
1889 goto out_err;
1890 }
1891
1892 unix_state_lock(other);
1893
1894 if (sock_flag(other, SOCK_DEAD) ||
1895 (other->sk_shutdown & RCV_SHUTDOWN))
1896 goto pipe_err_free;
1897
1898 maybe_add_creds(skb, sock, other);
1899 skb_queue_tail(&other->sk_receive_queue, skb);
1900 unix_state_unlock(other);
1901 other->sk_data_ready(other);
1902 sent += size;
1903 }
1904
1905 scm_destroy(&scm);
1906
1907 return sent;
1908
1909pipe_err_free:
1910 unix_state_unlock(other);
1911 kfree_skb(skb);
1912pipe_err:
1913 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1914 send_sig(SIGPIPE, current, 0);
1915 err = -EPIPE;
1916out_err:
1917 scm_destroy(&scm);
1918 return sent ? : err;
1919}
1920
1921static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
1922 int offset, size_t size, int flags)
1923{
1924 int err;
1925 bool send_sigpipe = false;
1926 bool init_scm = true;
1927 struct scm_cookie scm;
1928 struct sock *other, *sk = socket->sk;
1929 struct sk_buff *skb, *newskb = NULL, *tail = NULL;
1930
1931 if (flags & MSG_OOB)
1932 return -EOPNOTSUPP;
1933
1934 other = unix_peer(sk);
1935 if (!other || sk->sk_state != TCP_ESTABLISHED)
1936 return -ENOTCONN;
1937
1938 if (false) {
1939alloc_skb:
1940 unix_state_unlock(other);
1941 mutex_unlock(&unix_sk(other)->iolock);
1942 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
1943 &err, 0);
1944 if (!newskb)
1945 goto err;
1946 }
1947
1948 /* we must acquire iolock as we modify already present
1949 * skbs in the sk_receive_queue and mess with skb->len
1950 */
1951 err = mutex_lock_interruptible(&unix_sk(other)->iolock);
1952 if (err) {
1953 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
1954 goto err;
1955 }
1956
1957 if (sk->sk_shutdown & SEND_SHUTDOWN) {
1958 err = -EPIPE;
1959 send_sigpipe = true;
1960 goto err_unlock;
1961 }
1962
1963 unix_state_lock(other);
1964
1965 if (sock_flag(other, SOCK_DEAD) ||
1966 other->sk_shutdown & RCV_SHUTDOWN) {
1967 err = -EPIPE;
1968 send_sigpipe = true;
1969 goto err_state_unlock;
1970 }
1971
1972 if (init_scm) {
1973 err = maybe_init_creds(&scm, socket, other);
1974 if (err)
1975 goto err_state_unlock;
1976 init_scm = false;
1977 }
1978
1979 skb = skb_peek_tail(&other->sk_receive_queue);
1980 if (tail && tail == skb) {
1981 skb = newskb;
1982 } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
1983 if (newskb) {
1984 skb = newskb;
1985 } else {
1986 tail = skb;
1987 goto alloc_skb;
1988 }
1989 } else if (newskb) {
1990 /* this is fast path, we don't necessarily need to
1991 * call to kfree_skb even though with newskb == NULL
1992 * this - does no harm
1993 */
1994 consume_skb(newskb);
1995 newskb = NULL;
1996 }
1997
1998 if (skb_append_pagefrags(skb, page, offset, size)) {
1999 tail = skb;
2000 goto alloc_skb;
2001 }
2002
2003 skb->len += size;
2004 skb->data_len += size;
2005 skb->truesize += size;
2006 refcount_add(size, &sk->sk_wmem_alloc);
2007
2008 if (newskb) {
2009 err = unix_scm_to_skb(&scm, skb, false);
2010 if (err)
2011 goto err_state_unlock;
2012 spin_lock(&other->sk_receive_queue.lock);
2013 __skb_queue_tail(&other->sk_receive_queue, newskb);
2014 spin_unlock(&other->sk_receive_queue.lock);
2015 }
2016
2017 unix_state_unlock(other);
2018 mutex_unlock(&unix_sk(other)->iolock);
2019
2020 other->sk_data_ready(other);
2021 scm_destroy(&scm);
2022 return size;
2023
2024err_state_unlock:
2025 unix_state_unlock(other);
2026err_unlock:
2027 mutex_unlock(&unix_sk(other)->iolock);
2028err:
2029 kfree_skb(newskb);
2030 if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2031 send_sig(SIGPIPE, current, 0);
2032 if (!init_scm)
2033 scm_destroy(&scm);
2034 return err;
2035}
2036
2037static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2038 size_t len)
2039{
2040 int err;
2041 struct sock *sk = sock->sk;
2042
2043 err = sock_error(sk);
2044 if (err)
2045 return err;
2046
2047 if (sk->sk_state != TCP_ESTABLISHED)
2048 return -ENOTCONN;
2049
2050 if (msg->msg_namelen)
2051 msg->msg_namelen = 0;
2052
2053 return unix_dgram_sendmsg(sock, msg, len);
2054}
2055
2056static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2057 size_t size, int flags)
2058{
2059 struct sock *sk = sock->sk;
2060
2061 if (sk->sk_state != TCP_ESTABLISHED)
2062 return -ENOTCONN;
2063
2064 return unix_dgram_recvmsg(sock, msg, size, flags);
2065}
2066
2067static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2068{
2069 struct unix_sock *u = unix_sk(sk);
2070
2071 if (u->addr) {
2072 msg->msg_namelen = u->addr->len;
2073 memcpy(msg->msg_name, u->addr->name, u->addr->len);
2074 }
2075}
2076
2077static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
2078 size_t size, int flags)
2079{
2080 struct scm_cookie scm;
2081 struct sock *sk = sock->sk;
2082 struct unix_sock *u = unix_sk(sk);
2083 struct sk_buff *skb, *last;
2084 long timeo;
2085 int err;
2086 int peeked, skip;
2087
2088 err = -EOPNOTSUPP;
2089 if (flags&MSG_OOB)
2090 goto out;
2091
2092 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2093
2094 do {
2095 mutex_lock(&u->iolock);
2096
2097 skip = sk_peek_offset(sk, flags);
2098 skb = __skb_try_recv_datagram(sk, flags, NULL, &peeked, &skip,
2099 &err, &last);
2100 if (skb)
2101 break;
2102
2103 mutex_unlock(&u->iolock);
2104
2105 if (err != -EAGAIN)
2106 break;
2107 } while (timeo &&
2108 !__skb_wait_for_more_packets(sk, &err, &timeo, last));
2109
2110 if (!skb) { /* implies iolock unlocked */
2111 unix_state_lock(sk);
2112 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2113 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2114 (sk->sk_shutdown & RCV_SHUTDOWN))
2115 err = 0;
2116 unix_state_unlock(sk);
2117 goto out;
2118 }
2119
2120 if (wq_has_sleeper(&u->peer_wait))
2121 wake_up_interruptible_sync_poll(&u->peer_wait,
2122 EPOLLOUT | EPOLLWRNORM |
2123 EPOLLWRBAND);
2124
2125 if (msg->msg_name)
2126 unix_copy_addr(msg, skb->sk);
2127
2128 if (size > skb->len - skip)
2129 size = skb->len - skip;
2130 else if (size < skb->len - skip)
2131 msg->msg_flags |= MSG_TRUNC;
2132
2133 err = skb_copy_datagram_msg(skb, skip, msg, size);
2134 if (err)
2135 goto out_free;
2136
2137 if (sock_flag(sk, SOCK_RCVTSTAMP))
2138 __sock_recv_timestamp(msg, sk, skb);
2139
2140 memset(&scm, 0, sizeof(scm));
2141
2142 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2143 unix_set_secdata(&scm, skb);
2144
2145 if (!(flags & MSG_PEEK)) {
2146 if (UNIXCB(skb).fp)
2147 unix_detach_fds(&scm, skb);
2148
2149 sk_peek_offset_bwd(sk, skb->len);
2150 } else {
2151 /* It is questionable: on PEEK we could:
2152 - do not return fds - good, but too simple 8)
2153 - return fds, and do not return them on read (old strategy,
2154 apparently wrong)
2155 - clone fds (I chose it for now, it is the most universal
2156 solution)
2157
2158 POSIX 1003.1g does not actually define this clearly
2159 at all. POSIX 1003.1g doesn't define a lot of things
2160 clearly however!
2161
2162 */
2163
2164 sk_peek_offset_fwd(sk, size);
2165
2166 if (UNIXCB(skb).fp)
2167 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2168 }
2169 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2170
2171 scm_recv(sock, msg, &scm, flags);
2172
2173out_free:
2174 skb_free_datagram(sk, skb);
2175 mutex_unlock(&u->iolock);
2176out:
2177 return err;
2178}
2179
2180/*
2181 * Sleep until more data has arrived. But check for races..
2182 */
2183static long unix_stream_data_wait(struct sock *sk, long timeo,
2184 struct sk_buff *last, unsigned int last_len,
2185 bool freezable)
2186{
2187 struct sk_buff *tail;
2188 DEFINE_WAIT(wait);
2189
2190 unix_state_lock(sk);
2191
2192 for (;;) {
2193 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2194
2195 tail = skb_peek_tail(&sk->sk_receive_queue);
2196 if (tail != last ||
2197 (tail && tail->len != last_len) ||
2198 sk->sk_err ||
2199 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2200 signal_pending(current) ||
2201 !timeo)
2202 break;
2203
2204 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2205 unix_state_unlock(sk);
2206 if (freezable)
2207 timeo = freezable_schedule_timeout(timeo);
2208 else
2209 timeo = schedule_timeout(timeo);
2210 unix_state_lock(sk);
2211
2212 if (sock_flag(sk, SOCK_DEAD))
2213 break;
2214
2215 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2216 }
2217
2218 finish_wait(sk_sleep(sk), &wait);
2219 unix_state_unlock(sk);
2220 return timeo;
2221}
2222
2223static unsigned int unix_skb_len(const struct sk_buff *skb)
2224{
2225 return skb->len - UNIXCB(skb).consumed;
2226}
2227
2228struct unix_stream_read_state {
2229 int (*recv_actor)(struct sk_buff *, int, int,
2230 struct unix_stream_read_state *);
2231 struct socket *socket;
2232 struct msghdr *msg;
2233 struct pipe_inode_info *pipe;
2234 size_t size;
2235 int flags;
2236 unsigned int splice_flags;
2237};
2238
2239static int unix_stream_read_generic(struct unix_stream_read_state *state,
2240 bool freezable)
2241{
2242 struct scm_cookie scm;
2243 struct socket *sock = state->socket;
2244 struct sock *sk = sock->sk;
2245 struct unix_sock *u = unix_sk(sk);
2246 int copied = 0;
2247 int flags = state->flags;
2248 int noblock = flags & MSG_DONTWAIT;
2249 bool check_creds = false;
2250 int target;
2251 int err = 0;
2252 long timeo;
2253 int skip;
2254 size_t size = state->size;
2255 unsigned int last_len;
2256
2257 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2258 err = -EINVAL;
2259 goto out;
2260 }
2261
2262 if (unlikely(flags & MSG_OOB)) {
2263 err = -EOPNOTSUPP;
2264 goto out;
2265 }
2266
2267 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2268 timeo = sock_rcvtimeo(sk, noblock);
2269
2270 memset(&scm, 0, sizeof(scm));
2271
2272 /* Lock the socket to prevent queue disordering
2273 * while sleeps in memcpy_tomsg
2274 */
2275 mutex_lock(&u->iolock);
2276
2277 skip = max(sk_peek_offset(sk, flags), 0);
2278
2279 do {
2280 int chunk;
2281 bool drop_skb;
2282 struct sk_buff *skb, *last;
2283
2284redo:
2285 unix_state_lock(sk);
2286 if (sock_flag(sk, SOCK_DEAD)) {
2287 err = -ECONNRESET;
2288 goto unlock;
2289 }
2290 last = skb = skb_peek(&sk->sk_receive_queue);
2291 last_len = last ? last->len : 0;
2292again:
2293 if (skb == NULL) {
2294 if (copied >= target)
2295 goto unlock;
2296
2297 /*
2298 * POSIX 1003.1g mandates this order.
2299 */
2300
2301 err = sock_error(sk);
2302 if (err)
2303 goto unlock;
2304 if (sk->sk_shutdown & RCV_SHUTDOWN)
2305 goto unlock;
2306
2307 unix_state_unlock(sk);
2308 if (!timeo) {
2309 err = -EAGAIN;
2310 break;
2311 }
2312
2313 mutex_unlock(&u->iolock);
2314
2315 timeo = unix_stream_data_wait(sk, timeo, last,
2316 last_len, freezable);
2317
2318 if (signal_pending(current)) {
2319 err = sock_intr_errno(timeo);
2320 scm_destroy(&scm);
2321 goto out;
2322 }
2323
2324 mutex_lock(&u->iolock);
2325 goto redo;
2326unlock:
2327 unix_state_unlock(sk);
2328 break;
2329 }
2330
2331 while (skip >= unix_skb_len(skb)) {
2332 skip -= unix_skb_len(skb);
2333 last = skb;
2334 last_len = skb->len;
2335 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2336 if (!skb)
2337 goto again;
2338 }
2339
2340 unix_state_unlock(sk);
2341
2342 if (check_creds) {
2343 /* Never glue messages from different writers */
2344 if (!unix_skb_scm_eq(skb, &scm))
2345 break;
2346 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2347 /* Copy credentials */
2348 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2349 unix_set_secdata(&scm, skb);
2350 check_creds = true;
2351 }
2352
2353 /* Copy address just once */
2354 if (state->msg && state->msg->msg_name) {
2355 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2356 state->msg->msg_name);
2357 unix_copy_addr(state->msg, skb->sk);
2358 sunaddr = NULL;
2359 }
2360
2361 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2362 skb_get(skb);
2363 chunk = state->recv_actor(skb, skip, chunk, state);
2364 drop_skb = !unix_skb_len(skb);
2365 /* skb is only safe to use if !drop_skb */
2366 consume_skb(skb);
2367 if (chunk < 0) {
2368 if (copied == 0)
2369 copied = -EFAULT;
2370 break;
2371 }
2372 copied += chunk;
2373 size -= chunk;
2374
2375 if (drop_skb) {
2376 /* the skb was touched by a concurrent reader;
2377 * we should not expect anything from this skb
2378 * anymore and assume it invalid - we can be
2379 * sure it was dropped from the socket queue
2380 *
2381 * let's report a short read
2382 */
2383 err = 0;
2384 break;
2385 }
2386
2387 /* Mark read part of skb as used */
2388 if (!(flags & MSG_PEEK)) {
2389 UNIXCB(skb).consumed += chunk;
2390
2391 sk_peek_offset_bwd(sk, chunk);
2392
2393 if (UNIXCB(skb).fp)
2394 unix_detach_fds(&scm, skb);
2395
2396 if (unix_skb_len(skb))
2397 break;
2398
2399 skb_unlink(skb, &sk->sk_receive_queue);
2400 consume_skb(skb);
2401
2402 if (scm.fp)
2403 break;
2404 } else {
2405 /* It is questionable, see note in unix_dgram_recvmsg.
2406 */
2407 if (UNIXCB(skb).fp)
2408 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2409
2410 sk_peek_offset_fwd(sk, chunk);
2411
2412 if (UNIXCB(skb).fp)
2413 break;
2414
2415 skip = 0;
2416 last = skb;
2417 last_len = skb->len;
2418 unix_state_lock(sk);
2419 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2420 if (skb)
2421 goto again;
2422 unix_state_unlock(sk);
2423 break;
2424 }
2425 } while (size);
2426
2427 mutex_unlock(&u->iolock);
2428 if (state->msg)
2429 scm_recv(sock, state->msg, &scm, flags);
2430 else
2431 scm_destroy(&scm);
2432out:
2433 return copied ? : err;
2434}
2435
2436static int unix_stream_read_actor(struct sk_buff *skb,
2437 int skip, int chunk,
2438 struct unix_stream_read_state *state)
2439{
2440 int ret;
2441
2442 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2443 state->msg, chunk);
2444 return ret ?: chunk;
2445}
2446
2447static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2448 size_t size, int flags)
2449{
2450 struct unix_stream_read_state state = {
2451 .recv_actor = unix_stream_read_actor,
2452 .socket = sock,
2453 .msg = msg,
2454 .size = size,
2455 .flags = flags
2456 };
2457
2458 return unix_stream_read_generic(&state, true);
2459}
2460
2461static int unix_stream_splice_actor(struct sk_buff *skb,
2462 int skip, int chunk,
2463 struct unix_stream_read_state *state)
2464{
2465 return skb_splice_bits(skb, state->socket->sk,
2466 UNIXCB(skb).consumed + skip,
2467 state->pipe, chunk, state->splice_flags);
2468}
2469
2470static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2471 struct pipe_inode_info *pipe,
2472 size_t size, unsigned int flags)
2473{
2474 struct unix_stream_read_state state = {
2475 .recv_actor = unix_stream_splice_actor,
2476 .socket = sock,
2477 .pipe = pipe,
2478 .size = size,
2479 .splice_flags = flags,
2480 };
2481
2482 if (unlikely(*ppos))
2483 return -ESPIPE;
2484
2485 if (sock->file->f_flags & O_NONBLOCK ||
2486 flags & SPLICE_F_NONBLOCK)
2487 state.flags = MSG_DONTWAIT;
2488
2489 return unix_stream_read_generic(&state, false);
2490}
2491
2492static int unix_shutdown(struct socket *sock, int mode)
2493{
2494 struct sock *sk = sock->sk;
2495 struct sock *other;
2496
2497 if (mode < SHUT_RD || mode > SHUT_RDWR)
2498 return -EINVAL;
2499 /* This maps:
2500 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2501 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2502 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2503 */
2504 ++mode;
2505
2506 unix_state_lock(sk);
2507 sk->sk_shutdown |= mode;
2508 other = unix_peer(sk);
2509 if (other)
2510 sock_hold(other);
2511 unix_state_unlock(sk);
2512 sk->sk_state_change(sk);
2513
2514 if (other &&
2515 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2516
2517 int peer_mode = 0;
2518
2519 if (mode&RCV_SHUTDOWN)
2520 peer_mode |= SEND_SHUTDOWN;
2521 if (mode&SEND_SHUTDOWN)
2522 peer_mode |= RCV_SHUTDOWN;
2523 unix_state_lock(other);
2524 other->sk_shutdown |= peer_mode;
2525 unix_state_unlock(other);
2526 other->sk_state_change(other);
2527 if (peer_mode == SHUTDOWN_MASK)
2528 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2529 else if (peer_mode & RCV_SHUTDOWN)
2530 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2531 }
2532 if (other)
2533 sock_put(other);
2534
2535 return 0;
2536}
2537
2538long unix_inq_len(struct sock *sk)
2539{
2540 struct sk_buff *skb;
2541 long amount = 0;
2542
2543 if (sk->sk_state == TCP_LISTEN)
2544 return -EINVAL;
2545
2546 spin_lock(&sk->sk_receive_queue.lock);
2547 if (sk->sk_type == SOCK_STREAM ||
2548 sk->sk_type == SOCK_SEQPACKET) {
2549 skb_queue_walk(&sk->sk_receive_queue, skb)
2550 amount += unix_skb_len(skb);
2551 } else {
2552 skb = skb_peek(&sk->sk_receive_queue);
2553 if (skb)
2554 amount = skb->len;
2555 }
2556 spin_unlock(&sk->sk_receive_queue.lock);
2557
2558 return amount;
2559}
2560EXPORT_SYMBOL_GPL(unix_inq_len);
2561
2562long unix_outq_len(struct sock *sk)
2563{
2564 return sk_wmem_alloc_get(sk);
2565}
2566EXPORT_SYMBOL_GPL(unix_outq_len);
2567
2568static int unix_open_file(struct sock *sk)
2569{
2570 struct path path;
2571 struct file *f;
2572 int fd;
2573
2574 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
2575 return -EPERM;
2576
2577 unix_state_lock(sk);
2578 path = unix_sk(sk)->path;
2579 if (!path.dentry) {
2580 unix_state_unlock(sk);
2581 return -ENOENT;
2582 }
2583
2584 path_get(&path);
2585 unix_state_unlock(sk);
2586
2587 fd = get_unused_fd_flags(O_CLOEXEC);
2588 if (fd < 0)
2589 goto out;
2590
2591 f = dentry_open(&path, O_PATH, current_cred());
2592 if (IS_ERR(f)) {
2593 put_unused_fd(fd);
2594 fd = PTR_ERR(f);
2595 goto out;
2596 }
2597
2598 fd_install(fd, f);
2599out:
2600 path_put(&path);
2601
2602 return fd;
2603}
2604
2605static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2606{
2607 struct sock *sk = sock->sk;
2608 long amount = 0;
2609 int err;
2610
2611 switch (cmd) {
2612 case SIOCOUTQ:
2613 amount = unix_outq_len(sk);
2614 err = put_user(amount, (int __user *)arg);
2615 break;
2616 case SIOCINQ:
2617 amount = unix_inq_len(sk);
2618 if (amount < 0)
2619 err = amount;
2620 else
2621 err = put_user(amount, (int __user *)arg);
2622 break;
2623 case SIOCUNIXFILE:
2624 err = unix_open_file(sk);
2625 break;
2626 default:
2627 err = -ENOIOCTLCMD;
2628 break;
2629 }
2630 return err;
2631}
2632
2633static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2634{
2635 struct sock *sk = sock->sk;
2636 __poll_t mask;
2637
2638 sock_poll_wait(file, sk_sleep(sk), wait);
2639 mask = 0;
2640
2641 /* exceptional events? */
2642 if (sk->sk_err)
2643 mask |= EPOLLERR;
2644 if (sk->sk_shutdown == SHUTDOWN_MASK)
2645 mask |= EPOLLHUP;
2646 if (sk->sk_shutdown & RCV_SHUTDOWN)
2647 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2648
2649 /* readable? */
2650 if (!skb_queue_empty(&sk->sk_receive_queue))
2651 mask |= EPOLLIN | EPOLLRDNORM;
2652
2653 /* Connection-based need to check for termination and startup */
2654 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2655 sk->sk_state == TCP_CLOSE)
2656 mask |= EPOLLHUP;
2657
2658 /*
2659 * we set writable also when the other side has shut down the
2660 * connection. This prevents stuck sockets.
2661 */
2662 if (unix_writable(sk))
2663 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
2664
2665 return mask;
2666}
2667
2668static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
2669 poll_table *wait)
2670{
2671 struct sock *sk = sock->sk, *other;
2672 unsigned int writable;
2673 __poll_t mask;
2674
2675 sock_poll_wait(file, sk_sleep(sk), wait);
2676 mask = 0;
2677
2678 /* exceptional events? */
2679 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2680 mask |= EPOLLERR |
2681 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
2682
2683 if (sk->sk_shutdown & RCV_SHUTDOWN)
2684 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2685 if (sk->sk_shutdown == SHUTDOWN_MASK)
2686 mask |= EPOLLHUP;
2687
2688 /* readable? */
2689 if (!skb_queue_empty(&sk->sk_receive_queue))
2690 mask |= EPOLLIN | EPOLLRDNORM;
2691
2692 /* Connection-based need to check for termination and startup */
2693 if (sk->sk_type == SOCK_SEQPACKET) {
2694 if (sk->sk_state == TCP_CLOSE)
2695 mask |= EPOLLHUP;
2696 /* connection hasn't started yet? */
2697 if (sk->sk_state == TCP_SYN_SENT)
2698 return mask;
2699 }
2700
2701 /* No write status requested, avoid expensive OUT tests. */
2702 if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT)))
2703 return mask;
2704
2705 writable = unix_writable(sk);
2706 if (writable) {
2707 unix_state_lock(sk);
2708
2709 other = unix_peer(sk);
2710 if (other && unix_peer(other) != sk &&
2711 unix_recvq_full(other) &&
2712 unix_dgram_peer_wake_me(sk, other))
2713 writable = 0;
2714
2715 unix_state_unlock(sk);
2716 }
2717
2718 if (writable)
2719 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
2720 else
2721 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2722
2723 return mask;
2724}
2725
2726#ifdef CONFIG_PROC_FS
2727
2728#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2729
2730#define get_bucket(x) ((x) >> BUCKET_SPACE)
2731#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2732#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2733
2734static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2735{
2736 unsigned long offset = get_offset(*pos);
2737 unsigned long bucket = get_bucket(*pos);
2738 struct sock *sk;
2739 unsigned long count = 0;
2740
2741 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2742 if (sock_net(sk) != seq_file_net(seq))
2743 continue;
2744 if (++count == offset)
2745 break;
2746 }
2747
2748 return sk;
2749}
2750
2751static struct sock *unix_next_socket(struct seq_file *seq,
2752 struct sock *sk,
2753 loff_t *pos)
2754{
2755 unsigned long bucket;
2756
2757 while (sk > (struct sock *)SEQ_START_TOKEN) {
2758 sk = sk_next(sk);
2759 if (!sk)
2760 goto next_bucket;
2761 if (sock_net(sk) == seq_file_net(seq))
2762 return sk;
2763 }
2764
2765 do {
2766 sk = unix_from_bucket(seq, pos);
2767 if (sk)
2768 return sk;
2769
2770next_bucket:
2771 bucket = get_bucket(*pos) + 1;
2772 *pos = set_bucket_offset(bucket, 1);
2773 } while (bucket < ARRAY_SIZE(unix_socket_table));
2774
2775 return NULL;
2776}
2777
2778static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2779 __acquires(unix_table_lock)
2780{
2781 spin_lock(&unix_table_lock);
2782
2783 if (!*pos)
2784 return SEQ_START_TOKEN;
2785
2786 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2787 return NULL;
2788
2789 return unix_next_socket(seq, NULL, pos);
2790}
2791
2792static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2793{
2794 ++*pos;
2795 return unix_next_socket(seq, v, pos);
2796}
2797
2798static void unix_seq_stop(struct seq_file *seq, void *v)
2799 __releases(unix_table_lock)
2800{
2801 spin_unlock(&unix_table_lock);
2802}
2803
2804static int unix_seq_show(struct seq_file *seq, void *v)
2805{
2806
2807 if (v == SEQ_START_TOKEN)
2808 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2809 "Inode Path\n");
2810 else {
2811 struct sock *s = v;
2812 struct unix_sock *u = unix_sk(s);
2813 unix_state_lock(s);
2814
2815 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2816 s,
2817 refcount_read(&s->sk_refcnt),
2818 0,
2819 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2820 s->sk_type,
2821 s->sk_socket ?
2822 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2823 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2824 sock_i_ino(s));
2825
2826 if (u->addr) {
2827 int i, len;
2828 seq_putc(seq, ' ');
2829
2830 i = 0;
2831 len = u->addr->len - sizeof(short);
2832 if (!UNIX_ABSTRACT(s))
2833 len--;
2834 else {
2835 seq_putc(seq, '@');
2836 i++;
2837 }
2838 for ( ; i < len; i++)
2839 seq_putc(seq, u->addr->name->sun_path[i] ?:
2840 '@');
2841 }
2842 unix_state_unlock(s);
2843 seq_putc(seq, '\n');
2844 }
2845
2846 return 0;
2847}
2848
2849static const struct seq_operations unix_seq_ops = {
2850 .start = unix_seq_start,
2851 .next = unix_seq_next,
2852 .stop = unix_seq_stop,
2853 .show = unix_seq_show,
2854};
2855
2856static int unix_seq_open(struct inode *inode, struct file *file)
2857{
2858 return seq_open_net(inode, file, &unix_seq_ops,
2859 sizeof(struct seq_net_private));
2860}
2861
2862static const struct file_operations unix_seq_fops = {
2863 .open = unix_seq_open,
2864 .read = seq_read,
2865 .llseek = seq_lseek,
2866 .release = seq_release_net,
2867};
2868
2869#endif
2870
2871static const struct net_proto_family unix_family_ops = {
2872 .family = PF_UNIX,
2873 .create = unix_create,
2874 .owner = THIS_MODULE,
2875};
2876
2877
2878static int __net_init unix_net_init(struct net *net)
2879{
2880 int error = -ENOMEM;
2881
2882 net->unx.sysctl_max_dgram_qlen = 10;
2883 if (unix_sysctl_register(net))
2884 goto out;
2885
2886#ifdef CONFIG_PROC_FS
2887 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2888 unix_sysctl_unregister(net);
2889 goto out;
2890 }
2891#endif
2892 error = 0;
2893out:
2894 return error;
2895}
2896
2897static void __net_exit unix_net_exit(struct net *net)
2898{
2899 unix_sysctl_unregister(net);
2900 remove_proc_entry("unix", net->proc_net);
2901}
2902
2903static struct pernet_operations unix_net_ops = {
2904 .init = unix_net_init,
2905 .exit = unix_net_exit,
2906};
2907
2908static int __init af_unix_init(void)
2909{
2910 int rc = -1;
2911
2912 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2913
2914 rc = proto_register(&unix_proto, 1);
2915 if (rc != 0) {
2916 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
2917 goto out;
2918 }
2919
2920 sock_register(&unix_family_ops);
2921 register_pernet_subsys(&unix_net_ops);
2922out:
2923 return rc;
2924}
2925
2926static void __exit af_unix_exit(void)
2927{
2928 sock_unregister(PF_UNIX);
2929 proto_unregister(&unix_proto);
2930 unregister_pernet_subsys(&unix_net_ops);
2931}
2932
2933/* Earlier than device_initcall() so that other drivers invoking
2934 request_module() don't end up in a loop when modprobe tries
2935 to use a UNIX socket. But later than subsys_initcall() because
2936 we depend on stuff initialised there */
2937fs_initcall(af_unix_init);
2938module_exit(af_unix_exit);
2939
2940MODULE_LICENSE("GPL");
2941MODULE_ALIAS_NETPROTO(PF_UNIX);