Loading...
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.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
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->iolock))
665 return -EINTR;
666
667 sk->sk_peek_off = val;
668 mutex_unlock(&u->iolock);
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_allocation = GFP_KERNEL_ACCOUNT;
773 sk->sk_write_space = unix_write_space;
774 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
775 sk->sk_destruct = unix_sock_destructor;
776 u = unix_sk(sk);
777 u->path.dentry = NULL;
778 u->path.mnt = NULL;
779 spin_lock_init(&u->lock);
780 atomic_long_set(&u->inflight, 0);
781 INIT_LIST_HEAD(&u->link);
782 mutex_init(&u->iolock); /* single task reading lock */
783 mutex_init(&u->bindlock); /* single task binding lock */
784 init_waitqueue_head(&u->peer_wait);
785 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
786 unix_insert_socket(unix_sockets_unbound(sk), sk);
787out:
788 if (sk == NULL)
789 atomic_long_dec(&unix_nr_socks);
790 else {
791 local_bh_disable();
792 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
793 local_bh_enable();
794 }
795 return sk;
796}
797
798static int unix_create(struct net *net, struct socket *sock, int protocol,
799 int kern)
800{
801 if (protocol && protocol != PF_UNIX)
802 return -EPROTONOSUPPORT;
803
804 sock->state = SS_UNCONNECTED;
805
806 switch (sock->type) {
807 case SOCK_STREAM:
808 sock->ops = &unix_stream_ops;
809 break;
810 /*
811 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
812 * nothing uses it.
813 */
814 case SOCK_RAW:
815 sock->type = SOCK_DGRAM;
816 case SOCK_DGRAM:
817 sock->ops = &unix_dgram_ops;
818 break;
819 case SOCK_SEQPACKET:
820 sock->ops = &unix_seqpacket_ops;
821 break;
822 default:
823 return -ESOCKTNOSUPPORT;
824 }
825
826 return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
827}
828
829static int unix_release(struct socket *sock)
830{
831 struct sock *sk = sock->sk;
832
833 if (!sk)
834 return 0;
835
836 unix_release_sock(sk, 0);
837 sock->sk = NULL;
838
839 return 0;
840}
841
842static int unix_autobind(struct socket *sock)
843{
844 struct sock *sk = sock->sk;
845 struct net *net = sock_net(sk);
846 struct unix_sock *u = unix_sk(sk);
847 static u32 ordernum = 1;
848 struct unix_address *addr;
849 int err;
850 unsigned int retries = 0;
851
852 err = mutex_lock_interruptible(&u->bindlock);
853 if (err)
854 return err;
855
856 err = 0;
857 if (u->addr)
858 goto out;
859
860 err = -ENOMEM;
861 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
862 if (!addr)
863 goto out;
864
865 addr->name->sun_family = AF_UNIX;
866 atomic_set(&addr->refcnt, 1);
867
868retry:
869 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
870 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
871
872 spin_lock(&unix_table_lock);
873 ordernum = (ordernum+1)&0xFFFFF;
874
875 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
876 addr->hash)) {
877 spin_unlock(&unix_table_lock);
878 /*
879 * __unix_find_socket_byname() may take long time if many names
880 * are already in use.
881 */
882 cond_resched();
883 /* Give up if all names seems to be in use. */
884 if (retries++ == 0xFFFFF) {
885 err = -ENOSPC;
886 kfree(addr);
887 goto out;
888 }
889 goto retry;
890 }
891 addr->hash ^= sk->sk_type;
892
893 __unix_remove_socket(sk);
894 u->addr = addr;
895 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
896 spin_unlock(&unix_table_lock);
897 err = 0;
898
899out: mutex_unlock(&u->bindlock);
900 return err;
901}
902
903static struct sock *unix_find_other(struct net *net,
904 struct sockaddr_un *sunname, int len,
905 int type, unsigned int hash, int *error)
906{
907 struct sock *u;
908 struct path path;
909 int err = 0;
910
911 if (sunname->sun_path[0]) {
912 struct inode *inode;
913 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
914 if (err)
915 goto fail;
916 inode = d_backing_inode(path.dentry);
917 err = inode_permission(inode, MAY_WRITE);
918 if (err)
919 goto put_fail;
920
921 err = -ECONNREFUSED;
922 if (!S_ISSOCK(inode->i_mode))
923 goto put_fail;
924 u = unix_find_socket_byinode(inode);
925 if (!u)
926 goto put_fail;
927
928 if (u->sk_type == type)
929 touch_atime(&path);
930
931 path_put(&path);
932
933 err = -EPROTOTYPE;
934 if (u->sk_type != type) {
935 sock_put(u);
936 goto fail;
937 }
938 } else {
939 err = -ECONNREFUSED;
940 u = unix_find_socket_byname(net, sunname, len, type, hash);
941 if (u) {
942 struct dentry *dentry;
943 dentry = unix_sk(u)->path.dentry;
944 if (dentry)
945 touch_atime(&unix_sk(u)->path);
946 } else
947 goto fail;
948 }
949 return u;
950
951put_fail:
952 path_put(&path);
953fail:
954 *error = err;
955 return NULL;
956}
957
958static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
959{
960 struct dentry *dentry;
961 struct path path;
962 int err = 0;
963 /*
964 * Get the parent directory, calculate the hash for last
965 * component.
966 */
967 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
968 err = PTR_ERR(dentry);
969 if (IS_ERR(dentry))
970 return err;
971
972 /*
973 * All right, let's create it.
974 */
975 err = security_path_mknod(&path, dentry, mode, 0);
976 if (!err) {
977 err = vfs_mknod(d_inode(path.dentry), dentry, mode, 0);
978 if (!err) {
979 res->mnt = mntget(path.mnt);
980 res->dentry = dget(dentry);
981 }
982 }
983 done_path_create(&path, dentry);
984 return err;
985}
986
987static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
988{
989 struct sock *sk = sock->sk;
990 struct net *net = sock_net(sk);
991 struct unix_sock *u = unix_sk(sk);
992 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
993 char *sun_path = sunaddr->sun_path;
994 int err;
995 unsigned int hash;
996 struct unix_address *addr;
997 struct hlist_head *list;
998 struct path path = { NULL, NULL };
999
1000 err = -EINVAL;
1001 if (sunaddr->sun_family != AF_UNIX)
1002 goto out;
1003
1004 if (addr_len == sizeof(short)) {
1005 err = unix_autobind(sock);
1006 goto out;
1007 }
1008
1009 err = unix_mkname(sunaddr, addr_len, &hash);
1010 if (err < 0)
1011 goto out;
1012 addr_len = err;
1013
1014 if (sun_path[0]) {
1015 umode_t mode = S_IFSOCK |
1016 (SOCK_INODE(sock)->i_mode & ~current_umask());
1017 err = unix_mknod(sun_path, mode, &path);
1018 if (err) {
1019 if (err == -EEXIST)
1020 err = -EADDRINUSE;
1021 goto out;
1022 }
1023 }
1024
1025 err = mutex_lock_interruptible(&u->bindlock);
1026 if (err)
1027 goto out_put;
1028
1029 err = -EINVAL;
1030 if (u->addr)
1031 goto out_up;
1032
1033 err = -ENOMEM;
1034 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
1035 if (!addr)
1036 goto out_up;
1037
1038 memcpy(addr->name, sunaddr, addr_len);
1039 addr->len = addr_len;
1040 addr->hash = hash ^ sk->sk_type;
1041 atomic_set(&addr->refcnt, 1);
1042
1043 if (sun_path[0]) {
1044 addr->hash = UNIX_HASH_SIZE;
1045 hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE - 1);
1046 spin_lock(&unix_table_lock);
1047 u->path = path;
1048 list = &unix_socket_table[hash];
1049 } else {
1050 spin_lock(&unix_table_lock);
1051 err = -EADDRINUSE;
1052 if (__unix_find_socket_byname(net, sunaddr, addr_len,
1053 sk->sk_type, hash)) {
1054 unix_release_addr(addr);
1055 goto out_unlock;
1056 }
1057
1058 list = &unix_socket_table[addr->hash];
1059 }
1060
1061 err = 0;
1062 __unix_remove_socket(sk);
1063 u->addr = addr;
1064 __unix_insert_socket(list, sk);
1065
1066out_unlock:
1067 spin_unlock(&unix_table_lock);
1068out_up:
1069 mutex_unlock(&u->bindlock);
1070out_put:
1071 if (err)
1072 path_put(&path);
1073out:
1074 return err;
1075}
1076
1077static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1078{
1079 if (unlikely(sk1 == sk2) || !sk2) {
1080 unix_state_lock(sk1);
1081 return;
1082 }
1083 if (sk1 < sk2) {
1084 unix_state_lock(sk1);
1085 unix_state_lock_nested(sk2);
1086 } else {
1087 unix_state_lock(sk2);
1088 unix_state_lock_nested(sk1);
1089 }
1090}
1091
1092static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1093{
1094 if (unlikely(sk1 == sk2) || !sk2) {
1095 unix_state_unlock(sk1);
1096 return;
1097 }
1098 unix_state_unlock(sk1);
1099 unix_state_unlock(sk2);
1100}
1101
1102static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1103 int alen, int flags)
1104{
1105 struct sock *sk = sock->sk;
1106 struct net *net = sock_net(sk);
1107 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1108 struct sock *other;
1109 unsigned int hash;
1110 int err;
1111
1112 if (addr->sa_family != AF_UNSPEC) {
1113 err = unix_mkname(sunaddr, alen, &hash);
1114 if (err < 0)
1115 goto out;
1116 alen = err;
1117
1118 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1119 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1120 goto out;
1121
1122restart:
1123 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1124 if (!other)
1125 goto out;
1126
1127 unix_state_double_lock(sk, other);
1128
1129 /* Apparently VFS overslept socket death. Retry. */
1130 if (sock_flag(other, SOCK_DEAD)) {
1131 unix_state_double_unlock(sk, other);
1132 sock_put(other);
1133 goto restart;
1134 }
1135
1136 err = -EPERM;
1137 if (!unix_may_send(sk, other))
1138 goto out_unlock;
1139
1140 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1141 if (err)
1142 goto out_unlock;
1143
1144 } else {
1145 /*
1146 * 1003.1g breaking connected state with AF_UNSPEC
1147 */
1148 other = NULL;
1149 unix_state_double_lock(sk, other);
1150 }
1151
1152 /*
1153 * If it was connected, reconnect.
1154 */
1155 if (unix_peer(sk)) {
1156 struct sock *old_peer = unix_peer(sk);
1157 unix_peer(sk) = other;
1158 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1159
1160 unix_state_double_unlock(sk, other);
1161
1162 if (other != old_peer)
1163 unix_dgram_disconnected(sk, old_peer);
1164 sock_put(old_peer);
1165 } else {
1166 unix_peer(sk) = other;
1167 unix_state_double_unlock(sk, other);
1168 }
1169 return 0;
1170
1171out_unlock:
1172 unix_state_double_unlock(sk, other);
1173 sock_put(other);
1174out:
1175 return err;
1176}
1177
1178static long unix_wait_for_peer(struct sock *other, long timeo)
1179{
1180 struct unix_sock *u = unix_sk(other);
1181 int sched;
1182 DEFINE_WAIT(wait);
1183
1184 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1185
1186 sched = !sock_flag(other, SOCK_DEAD) &&
1187 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1188 unix_recvq_full(other);
1189
1190 unix_state_unlock(other);
1191
1192 if (sched)
1193 timeo = schedule_timeout(timeo);
1194
1195 finish_wait(&u->peer_wait, &wait);
1196 return timeo;
1197}
1198
1199static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1200 int addr_len, int flags)
1201{
1202 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1203 struct sock *sk = sock->sk;
1204 struct net *net = sock_net(sk);
1205 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1206 struct sock *newsk = NULL;
1207 struct sock *other = NULL;
1208 struct sk_buff *skb = NULL;
1209 unsigned int hash;
1210 int st;
1211 int err;
1212 long timeo;
1213
1214 err = unix_mkname(sunaddr, addr_len, &hash);
1215 if (err < 0)
1216 goto out;
1217 addr_len = err;
1218
1219 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1220 (err = unix_autobind(sock)) != 0)
1221 goto out;
1222
1223 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1224
1225 /* First of all allocate resources.
1226 If we will make it after state is locked,
1227 we will have to recheck all again in any case.
1228 */
1229
1230 err = -ENOMEM;
1231
1232 /* create new sock for complete connection */
1233 newsk = unix_create1(sock_net(sk), NULL, 0);
1234 if (newsk == NULL)
1235 goto out;
1236
1237 /* Allocate skb for sending to listening sock */
1238 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1239 if (skb == NULL)
1240 goto out;
1241
1242restart:
1243 /* Find listening sock. */
1244 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1245 if (!other)
1246 goto out;
1247
1248 /* Latch state of peer */
1249 unix_state_lock(other);
1250
1251 /* Apparently VFS overslept socket death. Retry. */
1252 if (sock_flag(other, SOCK_DEAD)) {
1253 unix_state_unlock(other);
1254 sock_put(other);
1255 goto restart;
1256 }
1257
1258 err = -ECONNREFUSED;
1259 if (other->sk_state != TCP_LISTEN)
1260 goto out_unlock;
1261 if (other->sk_shutdown & RCV_SHUTDOWN)
1262 goto out_unlock;
1263
1264 if (unix_recvq_full(other)) {
1265 err = -EAGAIN;
1266 if (!timeo)
1267 goto out_unlock;
1268
1269 timeo = unix_wait_for_peer(other, timeo);
1270
1271 err = sock_intr_errno(timeo);
1272 if (signal_pending(current))
1273 goto out;
1274 sock_put(other);
1275 goto restart;
1276 }
1277
1278 /* Latch our state.
1279
1280 It is tricky place. We need to grab our state lock and cannot
1281 drop lock on peer. It is dangerous because deadlock is
1282 possible. Connect to self case and simultaneous
1283 attempt to connect are eliminated by checking socket
1284 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1285 check this before attempt to grab lock.
1286
1287 Well, and we have to recheck the state after socket locked.
1288 */
1289 st = sk->sk_state;
1290
1291 switch (st) {
1292 case TCP_CLOSE:
1293 /* This is ok... continue with connect */
1294 break;
1295 case TCP_ESTABLISHED:
1296 /* Socket is already connected */
1297 err = -EISCONN;
1298 goto out_unlock;
1299 default:
1300 err = -EINVAL;
1301 goto out_unlock;
1302 }
1303
1304 unix_state_lock_nested(sk);
1305
1306 if (sk->sk_state != st) {
1307 unix_state_unlock(sk);
1308 unix_state_unlock(other);
1309 sock_put(other);
1310 goto restart;
1311 }
1312
1313 err = security_unix_stream_connect(sk, other, newsk);
1314 if (err) {
1315 unix_state_unlock(sk);
1316 goto out_unlock;
1317 }
1318
1319 /* The way is open! Fastly set all the necessary fields... */
1320
1321 sock_hold(sk);
1322 unix_peer(newsk) = sk;
1323 newsk->sk_state = TCP_ESTABLISHED;
1324 newsk->sk_type = sk->sk_type;
1325 init_peercred(newsk);
1326 newu = unix_sk(newsk);
1327 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1328 otheru = unix_sk(other);
1329
1330 /* copy address information from listening to new sock*/
1331 if (otheru->addr) {
1332 atomic_inc(&otheru->addr->refcnt);
1333 newu->addr = otheru->addr;
1334 }
1335 if (otheru->path.dentry) {
1336 path_get(&otheru->path);
1337 newu->path = otheru->path;
1338 }
1339
1340 /* Set credentials */
1341 copy_peercred(sk, other);
1342
1343 sock->state = SS_CONNECTED;
1344 sk->sk_state = TCP_ESTABLISHED;
1345 sock_hold(newsk);
1346
1347 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1348 unix_peer(sk) = newsk;
1349
1350 unix_state_unlock(sk);
1351
1352 /* take ten and and send info to listening sock */
1353 spin_lock(&other->sk_receive_queue.lock);
1354 __skb_queue_tail(&other->sk_receive_queue, skb);
1355 spin_unlock(&other->sk_receive_queue.lock);
1356 unix_state_unlock(other);
1357 other->sk_data_ready(other);
1358 sock_put(other);
1359 return 0;
1360
1361out_unlock:
1362 if (other)
1363 unix_state_unlock(other);
1364
1365out:
1366 kfree_skb(skb);
1367 if (newsk)
1368 unix_release_sock(newsk, 0);
1369 if (other)
1370 sock_put(other);
1371 return err;
1372}
1373
1374static int unix_socketpair(struct socket *socka, struct socket *sockb)
1375{
1376 struct sock *ska = socka->sk, *skb = sockb->sk;
1377
1378 /* Join our sockets back to back */
1379 sock_hold(ska);
1380 sock_hold(skb);
1381 unix_peer(ska) = skb;
1382 unix_peer(skb) = ska;
1383 init_peercred(ska);
1384 init_peercred(skb);
1385
1386 if (ska->sk_type != SOCK_DGRAM) {
1387 ska->sk_state = TCP_ESTABLISHED;
1388 skb->sk_state = TCP_ESTABLISHED;
1389 socka->state = SS_CONNECTED;
1390 sockb->state = SS_CONNECTED;
1391 }
1392 return 0;
1393}
1394
1395static void unix_sock_inherit_flags(const struct socket *old,
1396 struct socket *new)
1397{
1398 if (test_bit(SOCK_PASSCRED, &old->flags))
1399 set_bit(SOCK_PASSCRED, &new->flags);
1400 if (test_bit(SOCK_PASSSEC, &old->flags))
1401 set_bit(SOCK_PASSSEC, &new->flags);
1402}
1403
1404static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1405{
1406 struct sock *sk = sock->sk;
1407 struct sock *tsk;
1408 struct sk_buff *skb;
1409 int err;
1410
1411 err = -EOPNOTSUPP;
1412 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1413 goto out;
1414
1415 err = -EINVAL;
1416 if (sk->sk_state != TCP_LISTEN)
1417 goto out;
1418
1419 /* If socket state is TCP_LISTEN it cannot change (for now...),
1420 * so that no locks are necessary.
1421 */
1422
1423 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1424 if (!skb) {
1425 /* This means receive shutdown. */
1426 if (err == 0)
1427 err = -EINVAL;
1428 goto out;
1429 }
1430
1431 tsk = skb->sk;
1432 skb_free_datagram(sk, skb);
1433 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1434
1435 /* attach accepted sock to socket */
1436 unix_state_lock(tsk);
1437 newsock->state = SS_CONNECTED;
1438 unix_sock_inherit_flags(sock, newsock);
1439 sock_graft(tsk, newsock);
1440 unix_state_unlock(tsk);
1441 return 0;
1442
1443out:
1444 return err;
1445}
1446
1447
1448static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1449{
1450 struct sock *sk = sock->sk;
1451 struct unix_sock *u;
1452 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1453 int err = 0;
1454
1455 if (peer) {
1456 sk = unix_peer_get(sk);
1457
1458 err = -ENOTCONN;
1459 if (!sk)
1460 goto out;
1461 err = 0;
1462 } else {
1463 sock_hold(sk);
1464 }
1465
1466 u = unix_sk(sk);
1467 unix_state_lock(sk);
1468 if (!u->addr) {
1469 sunaddr->sun_family = AF_UNIX;
1470 sunaddr->sun_path[0] = 0;
1471 *uaddr_len = sizeof(short);
1472 } else {
1473 struct unix_address *addr = u->addr;
1474
1475 *uaddr_len = addr->len;
1476 memcpy(sunaddr, addr->name, *uaddr_len);
1477 }
1478 unix_state_unlock(sk);
1479 sock_put(sk);
1480out:
1481 return err;
1482}
1483
1484static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1485{
1486 int i;
1487
1488 scm->fp = UNIXCB(skb).fp;
1489 UNIXCB(skb).fp = NULL;
1490
1491 for (i = scm->fp->count-1; i >= 0; i--)
1492 unix_notinflight(scm->fp->user, scm->fp->fp[i]);
1493}
1494
1495static void unix_destruct_scm(struct sk_buff *skb)
1496{
1497 struct scm_cookie scm;
1498 memset(&scm, 0, sizeof(scm));
1499 scm.pid = UNIXCB(skb).pid;
1500 if (UNIXCB(skb).fp)
1501 unix_detach_fds(&scm, skb);
1502
1503 /* Alas, it calls VFS */
1504 /* So fscking what? fput() had been SMP-safe since the last Summer */
1505 scm_destroy(&scm);
1506 sock_wfree(skb);
1507}
1508
1509/*
1510 * The "user->unix_inflight" variable is protected by the garbage
1511 * collection lock, and we just read it locklessly here. If you go
1512 * over the limit, there might be a tiny race in actually noticing
1513 * it across threads. Tough.
1514 */
1515static inline bool too_many_unix_fds(struct task_struct *p)
1516{
1517 struct user_struct *user = current_user();
1518
1519 if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
1520 return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1521 return false;
1522}
1523
1524#define MAX_RECURSION_LEVEL 4
1525
1526static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1527{
1528 int i;
1529 unsigned char max_level = 0;
1530
1531 if (too_many_unix_fds(current))
1532 return -ETOOMANYREFS;
1533
1534 for (i = scm->fp->count - 1; i >= 0; i--) {
1535 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1536
1537 if (sk)
1538 max_level = max(max_level,
1539 unix_sk(sk)->recursion_level);
1540 }
1541 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1542 return -ETOOMANYREFS;
1543
1544 /*
1545 * Need to duplicate file references for the sake of garbage
1546 * collection. Otherwise a socket in the fps might become a
1547 * candidate for GC while the skb is not yet queued.
1548 */
1549 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1550 if (!UNIXCB(skb).fp)
1551 return -ENOMEM;
1552
1553 for (i = scm->fp->count - 1; i >= 0; i--)
1554 unix_inflight(scm->fp->user, scm->fp->fp[i]);
1555 return max_level;
1556}
1557
1558static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1559{
1560 int err = 0;
1561
1562 UNIXCB(skb).pid = get_pid(scm->pid);
1563 UNIXCB(skb).uid = scm->creds.uid;
1564 UNIXCB(skb).gid = scm->creds.gid;
1565 UNIXCB(skb).fp = NULL;
1566 unix_get_secdata(scm, skb);
1567 if (scm->fp && send_fds)
1568 err = unix_attach_fds(scm, skb);
1569
1570 skb->destructor = unix_destruct_scm;
1571 return err;
1572}
1573
1574static bool unix_passcred_enabled(const struct socket *sock,
1575 const struct sock *other)
1576{
1577 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1578 !other->sk_socket ||
1579 test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1580}
1581
1582/*
1583 * Some apps rely on write() giving SCM_CREDENTIALS
1584 * We include credentials if source or destination socket
1585 * asserted SOCK_PASSCRED.
1586 */
1587static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1588 const struct sock *other)
1589{
1590 if (UNIXCB(skb).pid)
1591 return;
1592 if (unix_passcred_enabled(sock, other)) {
1593 UNIXCB(skb).pid = get_pid(task_tgid(current));
1594 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1595 }
1596}
1597
1598static int maybe_init_creds(struct scm_cookie *scm,
1599 struct socket *socket,
1600 const struct sock *other)
1601{
1602 int err;
1603 struct msghdr msg = { .msg_controllen = 0 };
1604
1605 err = scm_send(socket, &msg, scm, false);
1606 if (err)
1607 return err;
1608
1609 if (unix_passcred_enabled(socket, other)) {
1610 scm->pid = get_pid(task_tgid(current));
1611 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1612 }
1613 return err;
1614}
1615
1616static bool unix_skb_scm_eq(struct sk_buff *skb,
1617 struct scm_cookie *scm)
1618{
1619 const struct unix_skb_parms *u = &UNIXCB(skb);
1620
1621 return u->pid == scm->pid &&
1622 uid_eq(u->uid, scm->creds.uid) &&
1623 gid_eq(u->gid, scm->creds.gid) &&
1624 unix_secdata_eq(scm, skb);
1625}
1626
1627/*
1628 * Send AF_UNIX data.
1629 */
1630
1631static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1632 size_t len)
1633{
1634 struct sock *sk = sock->sk;
1635 struct net *net = sock_net(sk);
1636 struct unix_sock *u = unix_sk(sk);
1637 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1638 struct sock *other = NULL;
1639 int namelen = 0; /* fake GCC */
1640 int err;
1641 unsigned int hash;
1642 struct sk_buff *skb;
1643 long timeo;
1644 struct scm_cookie scm;
1645 int max_level;
1646 int data_len = 0;
1647 int sk_locked;
1648
1649 wait_for_unix_gc();
1650 err = scm_send(sock, msg, &scm, false);
1651 if (err < 0)
1652 return err;
1653
1654 err = -EOPNOTSUPP;
1655 if (msg->msg_flags&MSG_OOB)
1656 goto out;
1657
1658 if (msg->msg_namelen) {
1659 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1660 if (err < 0)
1661 goto out;
1662 namelen = err;
1663 } else {
1664 sunaddr = NULL;
1665 err = -ENOTCONN;
1666 other = unix_peer_get(sk);
1667 if (!other)
1668 goto out;
1669 }
1670
1671 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1672 && (err = unix_autobind(sock)) != 0)
1673 goto out;
1674
1675 err = -EMSGSIZE;
1676 if (len > sk->sk_sndbuf - 32)
1677 goto out;
1678
1679 if (len > SKB_MAX_ALLOC) {
1680 data_len = min_t(size_t,
1681 len - SKB_MAX_ALLOC,
1682 MAX_SKB_FRAGS * PAGE_SIZE);
1683 data_len = PAGE_ALIGN(data_len);
1684
1685 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1686 }
1687
1688 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1689 msg->msg_flags & MSG_DONTWAIT, &err,
1690 PAGE_ALLOC_COSTLY_ORDER);
1691 if (skb == NULL)
1692 goto out;
1693
1694 err = unix_scm_to_skb(&scm, skb, true);
1695 if (err < 0)
1696 goto out_free;
1697 max_level = err + 1;
1698
1699 skb_put(skb, len - data_len);
1700 skb->data_len = data_len;
1701 skb->len = len;
1702 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1703 if (err)
1704 goto out_free;
1705
1706 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1707
1708restart:
1709 if (!other) {
1710 err = -ECONNRESET;
1711 if (sunaddr == NULL)
1712 goto out_free;
1713
1714 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1715 hash, &err);
1716 if (other == NULL)
1717 goto out_free;
1718 }
1719
1720 if (sk_filter(other, skb) < 0) {
1721 /* Toss the packet but do not return any error to the sender */
1722 err = len;
1723 goto out_free;
1724 }
1725
1726 sk_locked = 0;
1727 unix_state_lock(other);
1728restart_locked:
1729 err = -EPERM;
1730 if (!unix_may_send(sk, other))
1731 goto out_unlock;
1732
1733 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1734 /*
1735 * Check with 1003.1g - what should
1736 * datagram error
1737 */
1738 unix_state_unlock(other);
1739 sock_put(other);
1740
1741 if (!sk_locked)
1742 unix_state_lock(sk);
1743
1744 err = 0;
1745 if (unix_peer(sk) == other) {
1746 unix_peer(sk) = NULL;
1747 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1748
1749 unix_state_unlock(sk);
1750
1751 unix_dgram_disconnected(sk, other);
1752 sock_put(other);
1753 err = -ECONNREFUSED;
1754 } else {
1755 unix_state_unlock(sk);
1756 }
1757
1758 other = NULL;
1759 if (err)
1760 goto out_free;
1761 goto restart;
1762 }
1763
1764 err = -EPIPE;
1765 if (other->sk_shutdown & RCV_SHUTDOWN)
1766 goto out_unlock;
1767
1768 if (sk->sk_type != SOCK_SEQPACKET) {
1769 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1770 if (err)
1771 goto out_unlock;
1772 }
1773
1774 /* other == sk && unix_peer(other) != sk if
1775 * - unix_peer(sk) == NULL, destination address bound to sk
1776 * - unix_peer(sk) == sk by time of get but disconnected before lock
1777 */
1778 if (other != sk &&
1779 unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1780 if (timeo) {
1781 timeo = unix_wait_for_peer(other, timeo);
1782
1783 err = sock_intr_errno(timeo);
1784 if (signal_pending(current))
1785 goto out_free;
1786
1787 goto restart;
1788 }
1789
1790 if (!sk_locked) {
1791 unix_state_unlock(other);
1792 unix_state_double_lock(sk, other);
1793 }
1794
1795 if (unix_peer(sk) != other ||
1796 unix_dgram_peer_wake_me(sk, other)) {
1797 err = -EAGAIN;
1798 sk_locked = 1;
1799 goto out_unlock;
1800 }
1801
1802 if (!sk_locked) {
1803 sk_locked = 1;
1804 goto restart_locked;
1805 }
1806 }
1807
1808 if (unlikely(sk_locked))
1809 unix_state_unlock(sk);
1810
1811 if (sock_flag(other, SOCK_RCVTSTAMP))
1812 __net_timestamp(skb);
1813 maybe_add_creds(skb, sock, other);
1814 skb_queue_tail(&other->sk_receive_queue, skb);
1815 if (max_level > unix_sk(other)->recursion_level)
1816 unix_sk(other)->recursion_level = max_level;
1817 unix_state_unlock(other);
1818 other->sk_data_ready(other);
1819 sock_put(other);
1820 scm_destroy(&scm);
1821 return len;
1822
1823out_unlock:
1824 if (sk_locked)
1825 unix_state_unlock(sk);
1826 unix_state_unlock(other);
1827out_free:
1828 kfree_skb(skb);
1829out:
1830 if (other)
1831 sock_put(other);
1832 scm_destroy(&scm);
1833 return err;
1834}
1835
1836/* We use paged skbs for stream sockets, and limit occupancy to 32768
1837 * bytes, and a minimun of a full page.
1838 */
1839#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1840
1841static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
1842 size_t len)
1843{
1844 struct sock *sk = sock->sk;
1845 struct sock *other = NULL;
1846 int err, size;
1847 struct sk_buff *skb;
1848 int sent = 0;
1849 struct scm_cookie scm;
1850 bool fds_sent = false;
1851 int max_level;
1852 int data_len;
1853
1854 wait_for_unix_gc();
1855 err = scm_send(sock, msg, &scm, false);
1856 if (err < 0)
1857 return err;
1858
1859 err = -EOPNOTSUPP;
1860 if (msg->msg_flags&MSG_OOB)
1861 goto out_err;
1862
1863 if (msg->msg_namelen) {
1864 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1865 goto out_err;
1866 } else {
1867 err = -ENOTCONN;
1868 other = unix_peer(sk);
1869 if (!other)
1870 goto out_err;
1871 }
1872
1873 if (sk->sk_shutdown & SEND_SHUTDOWN)
1874 goto pipe_err;
1875
1876 while (sent < len) {
1877 size = len - sent;
1878
1879 /* Keep two messages in the pipe so it schedules better */
1880 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1881
1882 /* allow fallback to order-0 allocations */
1883 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1884
1885 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1886
1887 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
1888
1889 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1890 msg->msg_flags & MSG_DONTWAIT, &err,
1891 get_order(UNIX_SKB_FRAGS_SZ));
1892 if (!skb)
1893 goto out_err;
1894
1895 /* Only send the fds in the first buffer */
1896 err = unix_scm_to_skb(&scm, skb, !fds_sent);
1897 if (err < 0) {
1898 kfree_skb(skb);
1899 goto out_err;
1900 }
1901 max_level = err + 1;
1902 fds_sent = true;
1903
1904 skb_put(skb, size - data_len);
1905 skb->data_len = data_len;
1906 skb->len = size;
1907 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
1908 if (err) {
1909 kfree_skb(skb);
1910 goto out_err;
1911 }
1912
1913 unix_state_lock(other);
1914
1915 if (sock_flag(other, SOCK_DEAD) ||
1916 (other->sk_shutdown & RCV_SHUTDOWN))
1917 goto pipe_err_free;
1918
1919 maybe_add_creds(skb, sock, other);
1920 skb_queue_tail(&other->sk_receive_queue, skb);
1921 if (max_level > unix_sk(other)->recursion_level)
1922 unix_sk(other)->recursion_level = max_level;
1923 unix_state_unlock(other);
1924 other->sk_data_ready(other);
1925 sent += size;
1926 }
1927
1928 scm_destroy(&scm);
1929
1930 return sent;
1931
1932pipe_err_free:
1933 unix_state_unlock(other);
1934 kfree_skb(skb);
1935pipe_err:
1936 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1937 send_sig(SIGPIPE, current, 0);
1938 err = -EPIPE;
1939out_err:
1940 scm_destroy(&scm);
1941 return sent ? : err;
1942}
1943
1944static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
1945 int offset, size_t size, int flags)
1946{
1947 int err;
1948 bool send_sigpipe = false;
1949 bool init_scm = true;
1950 struct scm_cookie scm;
1951 struct sock *other, *sk = socket->sk;
1952 struct sk_buff *skb, *newskb = NULL, *tail = NULL;
1953
1954 if (flags & MSG_OOB)
1955 return -EOPNOTSUPP;
1956
1957 other = unix_peer(sk);
1958 if (!other || sk->sk_state != TCP_ESTABLISHED)
1959 return -ENOTCONN;
1960
1961 if (false) {
1962alloc_skb:
1963 unix_state_unlock(other);
1964 mutex_unlock(&unix_sk(other)->iolock);
1965 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
1966 &err, 0);
1967 if (!newskb)
1968 goto err;
1969 }
1970
1971 /* we must acquire iolock as we modify already present
1972 * skbs in the sk_receive_queue and mess with skb->len
1973 */
1974 err = mutex_lock_interruptible(&unix_sk(other)->iolock);
1975 if (err) {
1976 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
1977 goto err;
1978 }
1979
1980 if (sk->sk_shutdown & SEND_SHUTDOWN) {
1981 err = -EPIPE;
1982 send_sigpipe = true;
1983 goto err_unlock;
1984 }
1985
1986 unix_state_lock(other);
1987
1988 if (sock_flag(other, SOCK_DEAD) ||
1989 other->sk_shutdown & RCV_SHUTDOWN) {
1990 err = -EPIPE;
1991 send_sigpipe = true;
1992 goto err_state_unlock;
1993 }
1994
1995 if (init_scm) {
1996 err = maybe_init_creds(&scm, socket, other);
1997 if (err)
1998 goto err_state_unlock;
1999 init_scm = false;
2000 }
2001
2002 skb = skb_peek_tail(&other->sk_receive_queue);
2003 if (tail && tail == skb) {
2004 skb = newskb;
2005 } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
2006 if (newskb) {
2007 skb = newskb;
2008 } else {
2009 tail = skb;
2010 goto alloc_skb;
2011 }
2012 } else if (newskb) {
2013 /* this is fast path, we don't necessarily need to
2014 * call to kfree_skb even though with newskb == NULL
2015 * this - does no harm
2016 */
2017 consume_skb(newskb);
2018 newskb = NULL;
2019 }
2020
2021 if (skb_append_pagefrags(skb, page, offset, size)) {
2022 tail = skb;
2023 goto alloc_skb;
2024 }
2025
2026 skb->len += size;
2027 skb->data_len += size;
2028 skb->truesize += size;
2029 atomic_add(size, &sk->sk_wmem_alloc);
2030
2031 if (newskb) {
2032 err = unix_scm_to_skb(&scm, skb, false);
2033 if (err)
2034 goto err_state_unlock;
2035 spin_lock(&other->sk_receive_queue.lock);
2036 __skb_queue_tail(&other->sk_receive_queue, newskb);
2037 spin_unlock(&other->sk_receive_queue.lock);
2038 }
2039
2040 unix_state_unlock(other);
2041 mutex_unlock(&unix_sk(other)->iolock);
2042
2043 other->sk_data_ready(other);
2044 scm_destroy(&scm);
2045 return size;
2046
2047err_state_unlock:
2048 unix_state_unlock(other);
2049err_unlock:
2050 mutex_unlock(&unix_sk(other)->iolock);
2051err:
2052 kfree_skb(newskb);
2053 if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2054 send_sig(SIGPIPE, current, 0);
2055 if (!init_scm)
2056 scm_destroy(&scm);
2057 return err;
2058}
2059
2060static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2061 size_t len)
2062{
2063 int err;
2064 struct sock *sk = sock->sk;
2065
2066 err = sock_error(sk);
2067 if (err)
2068 return err;
2069
2070 if (sk->sk_state != TCP_ESTABLISHED)
2071 return -ENOTCONN;
2072
2073 if (msg->msg_namelen)
2074 msg->msg_namelen = 0;
2075
2076 return unix_dgram_sendmsg(sock, msg, len);
2077}
2078
2079static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2080 size_t size, int flags)
2081{
2082 struct sock *sk = sock->sk;
2083
2084 if (sk->sk_state != TCP_ESTABLISHED)
2085 return -ENOTCONN;
2086
2087 return unix_dgram_recvmsg(sock, msg, size, flags);
2088}
2089
2090static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2091{
2092 struct unix_sock *u = unix_sk(sk);
2093
2094 if (u->addr) {
2095 msg->msg_namelen = u->addr->len;
2096 memcpy(msg->msg_name, u->addr->name, u->addr->len);
2097 }
2098}
2099
2100static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
2101 size_t size, int flags)
2102{
2103 struct scm_cookie scm;
2104 struct sock *sk = sock->sk;
2105 struct unix_sock *u = unix_sk(sk);
2106 struct sk_buff *skb, *last;
2107 long timeo;
2108 int err;
2109 int peeked, skip;
2110
2111 err = -EOPNOTSUPP;
2112 if (flags&MSG_OOB)
2113 goto out;
2114
2115 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2116
2117 do {
2118 mutex_lock(&u->iolock);
2119
2120 skip = sk_peek_offset(sk, flags);
2121 skb = __skb_try_recv_datagram(sk, flags, NULL, &peeked, &skip,
2122 &err, &last);
2123 if (skb)
2124 break;
2125
2126 mutex_unlock(&u->iolock);
2127
2128 if (err != -EAGAIN)
2129 break;
2130 } while (timeo &&
2131 !__skb_wait_for_more_packets(sk, &err, &timeo, last));
2132
2133 if (!skb) { /* implies iolock unlocked */
2134 unix_state_lock(sk);
2135 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2136 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2137 (sk->sk_shutdown & RCV_SHUTDOWN))
2138 err = 0;
2139 unix_state_unlock(sk);
2140 goto out;
2141 }
2142
2143 if (wq_has_sleeper(&u->peer_wait))
2144 wake_up_interruptible_sync_poll(&u->peer_wait,
2145 POLLOUT | POLLWRNORM |
2146 POLLWRBAND);
2147
2148 if (msg->msg_name)
2149 unix_copy_addr(msg, skb->sk);
2150
2151 if (size > skb->len - skip)
2152 size = skb->len - skip;
2153 else if (size < skb->len - skip)
2154 msg->msg_flags |= MSG_TRUNC;
2155
2156 err = skb_copy_datagram_msg(skb, skip, msg, size);
2157 if (err)
2158 goto out_free;
2159
2160 if (sock_flag(sk, SOCK_RCVTSTAMP))
2161 __sock_recv_timestamp(msg, sk, skb);
2162
2163 memset(&scm, 0, sizeof(scm));
2164
2165 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2166 unix_set_secdata(&scm, skb);
2167
2168 if (!(flags & MSG_PEEK)) {
2169 if (UNIXCB(skb).fp)
2170 unix_detach_fds(&scm, skb);
2171
2172 sk_peek_offset_bwd(sk, skb->len);
2173 } else {
2174 /* It is questionable: on PEEK we could:
2175 - do not return fds - good, but too simple 8)
2176 - return fds, and do not return them on read (old strategy,
2177 apparently wrong)
2178 - clone fds (I chose it for now, it is the most universal
2179 solution)
2180
2181 POSIX 1003.1g does not actually define this clearly
2182 at all. POSIX 1003.1g doesn't define a lot of things
2183 clearly however!
2184
2185 */
2186
2187 sk_peek_offset_fwd(sk, size);
2188
2189 if (UNIXCB(skb).fp)
2190 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2191 }
2192 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2193
2194 scm_recv(sock, msg, &scm, flags);
2195
2196out_free:
2197 skb_free_datagram(sk, skb);
2198 mutex_unlock(&u->iolock);
2199out:
2200 return err;
2201}
2202
2203/*
2204 * Sleep until more data has arrived. But check for races..
2205 */
2206static long unix_stream_data_wait(struct sock *sk, long timeo,
2207 struct sk_buff *last, unsigned int last_len,
2208 bool freezable)
2209{
2210 struct sk_buff *tail;
2211 DEFINE_WAIT(wait);
2212
2213 unix_state_lock(sk);
2214
2215 for (;;) {
2216 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2217
2218 tail = skb_peek_tail(&sk->sk_receive_queue);
2219 if (tail != last ||
2220 (tail && tail->len != last_len) ||
2221 sk->sk_err ||
2222 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2223 signal_pending(current) ||
2224 !timeo)
2225 break;
2226
2227 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2228 unix_state_unlock(sk);
2229 if (freezable)
2230 timeo = freezable_schedule_timeout(timeo);
2231 else
2232 timeo = schedule_timeout(timeo);
2233 unix_state_lock(sk);
2234
2235 if (sock_flag(sk, SOCK_DEAD))
2236 break;
2237
2238 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2239 }
2240
2241 finish_wait(sk_sleep(sk), &wait);
2242 unix_state_unlock(sk);
2243 return timeo;
2244}
2245
2246static unsigned int unix_skb_len(const struct sk_buff *skb)
2247{
2248 return skb->len - UNIXCB(skb).consumed;
2249}
2250
2251struct unix_stream_read_state {
2252 int (*recv_actor)(struct sk_buff *, int, int,
2253 struct unix_stream_read_state *);
2254 struct socket *socket;
2255 struct msghdr *msg;
2256 struct pipe_inode_info *pipe;
2257 size_t size;
2258 int flags;
2259 unsigned int splice_flags;
2260};
2261
2262static int unix_stream_read_generic(struct unix_stream_read_state *state,
2263 bool freezable)
2264{
2265 struct scm_cookie scm;
2266 struct socket *sock = state->socket;
2267 struct sock *sk = sock->sk;
2268 struct unix_sock *u = unix_sk(sk);
2269 int copied = 0;
2270 int flags = state->flags;
2271 int noblock = flags & MSG_DONTWAIT;
2272 bool check_creds = false;
2273 int target;
2274 int err = 0;
2275 long timeo;
2276 int skip;
2277 size_t size = state->size;
2278 unsigned int last_len;
2279
2280 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2281 err = -EINVAL;
2282 goto out;
2283 }
2284
2285 if (unlikely(flags & MSG_OOB)) {
2286 err = -EOPNOTSUPP;
2287 goto out;
2288 }
2289
2290 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2291 timeo = sock_rcvtimeo(sk, noblock);
2292
2293 memset(&scm, 0, sizeof(scm));
2294
2295 /* Lock the socket to prevent queue disordering
2296 * while sleeps in memcpy_tomsg
2297 */
2298 mutex_lock(&u->iolock);
2299
2300 if (flags & MSG_PEEK)
2301 skip = sk_peek_offset(sk, flags);
2302 else
2303 skip = 0;
2304
2305 do {
2306 int chunk;
2307 bool drop_skb;
2308 struct sk_buff *skb, *last;
2309
2310redo:
2311 unix_state_lock(sk);
2312 if (sock_flag(sk, SOCK_DEAD)) {
2313 err = -ECONNRESET;
2314 goto unlock;
2315 }
2316 last = skb = skb_peek(&sk->sk_receive_queue);
2317 last_len = last ? last->len : 0;
2318again:
2319 if (skb == NULL) {
2320 unix_sk(sk)->recursion_level = 0;
2321 if (copied >= target)
2322 goto unlock;
2323
2324 /*
2325 * POSIX 1003.1g mandates this order.
2326 */
2327
2328 err = sock_error(sk);
2329 if (err)
2330 goto unlock;
2331 if (sk->sk_shutdown & RCV_SHUTDOWN)
2332 goto unlock;
2333
2334 unix_state_unlock(sk);
2335 if (!timeo) {
2336 err = -EAGAIN;
2337 break;
2338 }
2339
2340 mutex_unlock(&u->iolock);
2341
2342 timeo = unix_stream_data_wait(sk, timeo, last,
2343 last_len, freezable);
2344
2345 if (signal_pending(current)) {
2346 err = sock_intr_errno(timeo);
2347 scm_destroy(&scm);
2348 goto out;
2349 }
2350
2351 mutex_lock(&u->iolock);
2352 goto redo;
2353unlock:
2354 unix_state_unlock(sk);
2355 break;
2356 }
2357
2358 while (skip >= unix_skb_len(skb)) {
2359 skip -= unix_skb_len(skb);
2360 last = skb;
2361 last_len = skb->len;
2362 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2363 if (!skb)
2364 goto again;
2365 }
2366
2367 unix_state_unlock(sk);
2368
2369 if (check_creds) {
2370 /* Never glue messages from different writers */
2371 if (!unix_skb_scm_eq(skb, &scm))
2372 break;
2373 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2374 /* Copy credentials */
2375 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2376 unix_set_secdata(&scm, skb);
2377 check_creds = true;
2378 }
2379
2380 /* Copy address just once */
2381 if (state->msg && state->msg->msg_name) {
2382 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2383 state->msg->msg_name);
2384 unix_copy_addr(state->msg, skb->sk);
2385 sunaddr = NULL;
2386 }
2387
2388 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2389 skb_get(skb);
2390 chunk = state->recv_actor(skb, skip, chunk, state);
2391 drop_skb = !unix_skb_len(skb);
2392 /* skb is only safe to use if !drop_skb */
2393 consume_skb(skb);
2394 if (chunk < 0) {
2395 if (copied == 0)
2396 copied = -EFAULT;
2397 break;
2398 }
2399 copied += chunk;
2400 size -= chunk;
2401
2402 if (drop_skb) {
2403 /* the skb was touched by a concurrent reader;
2404 * we should not expect anything from this skb
2405 * anymore and assume it invalid - we can be
2406 * sure it was dropped from the socket queue
2407 *
2408 * let's report a short read
2409 */
2410 err = 0;
2411 break;
2412 }
2413
2414 /* Mark read part of skb as used */
2415 if (!(flags & MSG_PEEK)) {
2416 UNIXCB(skb).consumed += chunk;
2417
2418 sk_peek_offset_bwd(sk, chunk);
2419
2420 if (UNIXCB(skb).fp)
2421 unix_detach_fds(&scm, skb);
2422
2423 if (unix_skb_len(skb))
2424 break;
2425
2426 skb_unlink(skb, &sk->sk_receive_queue);
2427 consume_skb(skb);
2428
2429 if (scm.fp)
2430 break;
2431 } else {
2432 /* It is questionable, see note in unix_dgram_recvmsg.
2433 */
2434 if (UNIXCB(skb).fp)
2435 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2436
2437 sk_peek_offset_fwd(sk, chunk);
2438
2439 if (UNIXCB(skb).fp)
2440 break;
2441
2442 skip = 0;
2443 last = skb;
2444 last_len = skb->len;
2445 unix_state_lock(sk);
2446 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2447 if (skb)
2448 goto again;
2449 unix_state_unlock(sk);
2450 break;
2451 }
2452 } while (size);
2453
2454 mutex_unlock(&u->iolock);
2455 if (state->msg)
2456 scm_recv(sock, state->msg, &scm, flags);
2457 else
2458 scm_destroy(&scm);
2459out:
2460 return copied ? : err;
2461}
2462
2463static int unix_stream_read_actor(struct sk_buff *skb,
2464 int skip, int chunk,
2465 struct unix_stream_read_state *state)
2466{
2467 int ret;
2468
2469 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2470 state->msg, chunk);
2471 return ret ?: chunk;
2472}
2473
2474static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2475 size_t size, int flags)
2476{
2477 struct unix_stream_read_state state = {
2478 .recv_actor = unix_stream_read_actor,
2479 .socket = sock,
2480 .msg = msg,
2481 .size = size,
2482 .flags = flags
2483 };
2484
2485 return unix_stream_read_generic(&state, true);
2486}
2487
2488static int unix_stream_splice_actor(struct sk_buff *skb,
2489 int skip, int chunk,
2490 struct unix_stream_read_state *state)
2491{
2492 return skb_splice_bits(skb, state->socket->sk,
2493 UNIXCB(skb).consumed + skip,
2494 state->pipe, chunk, state->splice_flags);
2495}
2496
2497static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2498 struct pipe_inode_info *pipe,
2499 size_t size, unsigned int flags)
2500{
2501 struct unix_stream_read_state state = {
2502 .recv_actor = unix_stream_splice_actor,
2503 .socket = sock,
2504 .pipe = pipe,
2505 .size = size,
2506 .splice_flags = flags,
2507 };
2508
2509 if (unlikely(*ppos))
2510 return -ESPIPE;
2511
2512 if (sock->file->f_flags & O_NONBLOCK ||
2513 flags & SPLICE_F_NONBLOCK)
2514 state.flags = MSG_DONTWAIT;
2515
2516 return unix_stream_read_generic(&state, false);
2517}
2518
2519static int unix_shutdown(struct socket *sock, int mode)
2520{
2521 struct sock *sk = sock->sk;
2522 struct sock *other;
2523
2524 if (mode < SHUT_RD || mode > SHUT_RDWR)
2525 return -EINVAL;
2526 /* This maps:
2527 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2528 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2529 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2530 */
2531 ++mode;
2532
2533 unix_state_lock(sk);
2534 sk->sk_shutdown |= mode;
2535 other = unix_peer(sk);
2536 if (other)
2537 sock_hold(other);
2538 unix_state_unlock(sk);
2539 sk->sk_state_change(sk);
2540
2541 if (other &&
2542 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2543
2544 int peer_mode = 0;
2545
2546 if (mode&RCV_SHUTDOWN)
2547 peer_mode |= SEND_SHUTDOWN;
2548 if (mode&SEND_SHUTDOWN)
2549 peer_mode |= RCV_SHUTDOWN;
2550 unix_state_lock(other);
2551 other->sk_shutdown |= peer_mode;
2552 unix_state_unlock(other);
2553 other->sk_state_change(other);
2554 if (peer_mode == SHUTDOWN_MASK)
2555 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2556 else if (peer_mode & RCV_SHUTDOWN)
2557 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2558 }
2559 if (other)
2560 sock_put(other);
2561
2562 return 0;
2563}
2564
2565long unix_inq_len(struct sock *sk)
2566{
2567 struct sk_buff *skb;
2568 long amount = 0;
2569
2570 if (sk->sk_state == TCP_LISTEN)
2571 return -EINVAL;
2572
2573 spin_lock(&sk->sk_receive_queue.lock);
2574 if (sk->sk_type == SOCK_STREAM ||
2575 sk->sk_type == SOCK_SEQPACKET) {
2576 skb_queue_walk(&sk->sk_receive_queue, skb)
2577 amount += unix_skb_len(skb);
2578 } else {
2579 skb = skb_peek(&sk->sk_receive_queue);
2580 if (skb)
2581 amount = skb->len;
2582 }
2583 spin_unlock(&sk->sk_receive_queue.lock);
2584
2585 return amount;
2586}
2587EXPORT_SYMBOL_GPL(unix_inq_len);
2588
2589long unix_outq_len(struct sock *sk)
2590{
2591 return sk_wmem_alloc_get(sk);
2592}
2593EXPORT_SYMBOL_GPL(unix_outq_len);
2594
2595static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2596{
2597 struct sock *sk = sock->sk;
2598 long amount = 0;
2599 int err;
2600
2601 switch (cmd) {
2602 case SIOCOUTQ:
2603 amount = unix_outq_len(sk);
2604 err = put_user(amount, (int __user *)arg);
2605 break;
2606 case SIOCINQ:
2607 amount = unix_inq_len(sk);
2608 if (amount < 0)
2609 err = amount;
2610 else
2611 err = put_user(amount, (int __user *)arg);
2612 break;
2613 default:
2614 err = -ENOIOCTLCMD;
2615 break;
2616 }
2617 return err;
2618}
2619
2620static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2621{
2622 struct sock *sk = sock->sk;
2623 unsigned int mask;
2624
2625 sock_poll_wait(file, sk_sleep(sk), wait);
2626 mask = 0;
2627
2628 /* exceptional events? */
2629 if (sk->sk_err)
2630 mask |= POLLERR;
2631 if (sk->sk_shutdown == SHUTDOWN_MASK)
2632 mask |= POLLHUP;
2633 if (sk->sk_shutdown & RCV_SHUTDOWN)
2634 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2635
2636 /* readable? */
2637 if (!skb_queue_empty(&sk->sk_receive_queue))
2638 mask |= POLLIN | POLLRDNORM;
2639
2640 /* Connection-based need to check for termination and startup */
2641 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2642 sk->sk_state == TCP_CLOSE)
2643 mask |= POLLHUP;
2644
2645 /*
2646 * we set writable also when the other side has shut down the
2647 * connection. This prevents stuck sockets.
2648 */
2649 if (unix_writable(sk))
2650 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2651
2652 return mask;
2653}
2654
2655static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2656 poll_table *wait)
2657{
2658 struct sock *sk = sock->sk, *other;
2659 unsigned int mask, writable;
2660
2661 sock_poll_wait(file, sk_sleep(sk), wait);
2662 mask = 0;
2663
2664 /* exceptional events? */
2665 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2666 mask |= POLLERR |
2667 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2668
2669 if (sk->sk_shutdown & RCV_SHUTDOWN)
2670 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2671 if (sk->sk_shutdown == SHUTDOWN_MASK)
2672 mask |= POLLHUP;
2673
2674 /* readable? */
2675 if (!skb_queue_empty(&sk->sk_receive_queue))
2676 mask |= POLLIN | POLLRDNORM;
2677
2678 /* Connection-based need to check for termination and startup */
2679 if (sk->sk_type == SOCK_SEQPACKET) {
2680 if (sk->sk_state == TCP_CLOSE)
2681 mask |= POLLHUP;
2682 /* connection hasn't started yet? */
2683 if (sk->sk_state == TCP_SYN_SENT)
2684 return mask;
2685 }
2686
2687 /* No write status requested, avoid expensive OUT tests. */
2688 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
2689 return mask;
2690
2691 writable = unix_writable(sk);
2692 if (writable) {
2693 unix_state_lock(sk);
2694
2695 other = unix_peer(sk);
2696 if (other && unix_peer(other) != sk &&
2697 unix_recvq_full(other) &&
2698 unix_dgram_peer_wake_me(sk, other))
2699 writable = 0;
2700
2701 unix_state_unlock(sk);
2702 }
2703
2704 if (writable)
2705 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2706 else
2707 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2708
2709 return mask;
2710}
2711
2712#ifdef CONFIG_PROC_FS
2713
2714#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2715
2716#define get_bucket(x) ((x) >> BUCKET_SPACE)
2717#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2718#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2719
2720static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2721{
2722 unsigned long offset = get_offset(*pos);
2723 unsigned long bucket = get_bucket(*pos);
2724 struct sock *sk;
2725 unsigned long count = 0;
2726
2727 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2728 if (sock_net(sk) != seq_file_net(seq))
2729 continue;
2730 if (++count == offset)
2731 break;
2732 }
2733
2734 return sk;
2735}
2736
2737static struct sock *unix_next_socket(struct seq_file *seq,
2738 struct sock *sk,
2739 loff_t *pos)
2740{
2741 unsigned long bucket;
2742
2743 while (sk > (struct sock *)SEQ_START_TOKEN) {
2744 sk = sk_next(sk);
2745 if (!sk)
2746 goto next_bucket;
2747 if (sock_net(sk) == seq_file_net(seq))
2748 return sk;
2749 }
2750
2751 do {
2752 sk = unix_from_bucket(seq, pos);
2753 if (sk)
2754 return sk;
2755
2756next_bucket:
2757 bucket = get_bucket(*pos) + 1;
2758 *pos = set_bucket_offset(bucket, 1);
2759 } while (bucket < ARRAY_SIZE(unix_socket_table));
2760
2761 return NULL;
2762}
2763
2764static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2765 __acquires(unix_table_lock)
2766{
2767 spin_lock(&unix_table_lock);
2768
2769 if (!*pos)
2770 return SEQ_START_TOKEN;
2771
2772 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2773 return NULL;
2774
2775 return unix_next_socket(seq, NULL, pos);
2776}
2777
2778static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2779{
2780 ++*pos;
2781 return unix_next_socket(seq, v, pos);
2782}
2783
2784static void unix_seq_stop(struct seq_file *seq, void *v)
2785 __releases(unix_table_lock)
2786{
2787 spin_unlock(&unix_table_lock);
2788}
2789
2790static int unix_seq_show(struct seq_file *seq, void *v)
2791{
2792
2793 if (v == SEQ_START_TOKEN)
2794 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2795 "Inode Path\n");
2796 else {
2797 struct sock *s = v;
2798 struct unix_sock *u = unix_sk(s);
2799 unix_state_lock(s);
2800
2801 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2802 s,
2803 atomic_read(&s->sk_refcnt),
2804 0,
2805 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2806 s->sk_type,
2807 s->sk_socket ?
2808 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2809 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2810 sock_i_ino(s));
2811
2812 if (u->addr) {
2813 int i, len;
2814 seq_putc(seq, ' ');
2815
2816 i = 0;
2817 len = u->addr->len - sizeof(short);
2818 if (!UNIX_ABSTRACT(s))
2819 len--;
2820 else {
2821 seq_putc(seq, '@');
2822 i++;
2823 }
2824 for ( ; i < len; i++)
2825 seq_putc(seq, u->addr->name->sun_path[i] ?:
2826 '@');
2827 }
2828 unix_state_unlock(s);
2829 seq_putc(seq, '\n');
2830 }
2831
2832 return 0;
2833}
2834
2835static const struct seq_operations unix_seq_ops = {
2836 .start = unix_seq_start,
2837 .next = unix_seq_next,
2838 .stop = unix_seq_stop,
2839 .show = unix_seq_show,
2840};
2841
2842static int unix_seq_open(struct inode *inode, struct file *file)
2843{
2844 return seq_open_net(inode, file, &unix_seq_ops,
2845 sizeof(struct seq_net_private));
2846}
2847
2848static const struct file_operations unix_seq_fops = {
2849 .owner = THIS_MODULE,
2850 .open = unix_seq_open,
2851 .read = seq_read,
2852 .llseek = seq_lseek,
2853 .release = seq_release_net,
2854};
2855
2856#endif
2857
2858static const struct net_proto_family unix_family_ops = {
2859 .family = PF_UNIX,
2860 .create = unix_create,
2861 .owner = THIS_MODULE,
2862};
2863
2864
2865static int __net_init unix_net_init(struct net *net)
2866{
2867 int error = -ENOMEM;
2868
2869 net->unx.sysctl_max_dgram_qlen = 10;
2870 if (unix_sysctl_register(net))
2871 goto out;
2872
2873#ifdef CONFIG_PROC_FS
2874 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2875 unix_sysctl_unregister(net);
2876 goto out;
2877 }
2878#endif
2879 error = 0;
2880out:
2881 return error;
2882}
2883
2884static void __net_exit unix_net_exit(struct net *net)
2885{
2886 unix_sysctl_unregister(net);
2887 remove_proc_entry("unix", net->proc_net);
2888}
2889
2890static struct pernet_operations unix_net_ops = {
2891 .init = unix_net_init,
2892 .exit = unix_net_exit,
2893};
2894
2895static int __init af_unix_init(void)
2896{
2897 int rc = -1;
2898
2899 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2900
2901 rc = proto_register(&unix_proto, 1);
2902 if (rc != 0) {
2903 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
2904 goto out;
2905 }
2906
2907 sock_register(&unix_family_ops);
2908 register_pernet_subsys(&unix_net_ops);
2909out:
2910 return rc;
2911}
2912
2913static void __exit af_unix_exit(void)
2914{
2915 sock_unregister(PF_UNIX);
2916 proto_unregister(&unix_proto);
2917 unregister_pernet_subsys(&unix_net_ops);
2918}
2919
2920/* Earlier than device_initcall() so that other drivers invoking
2921 request_module() don't end up in a loop when modprobe tries
2922 to use a UNIX socket. But later than subsys_initcall() because
2923 we depend on stuff initialised there */
2924fs_initcall(af_unix_init);
2925module_exit(af_unix_exit);
2926
2927MODULE_LICENSE("GPL");
2928MODULE_ALIAS_NETPROTO(PF_UNIX);