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1/*
2 * NET4: Implementation of BSD Unix domain sockets.
3 *
4 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * Fixes:
12 * Linus Torvalds : Assorted bug cures.
13 * Niibe Yutaka : async I/O support.
14 * Carsten Paeth : PF_UNIX check, address fixes.
15 * Alan Cox : Limit size of allocated blocks.
16 * Alan Cox : Fixed the stupid socketpair bug.
17 * Alan Cox : BSD compatibility fine tuning.
18 * Alan Cox : Fixed a bug in connect when interrupted.
19 * Alan Cox : Sorted out a proper draft version of
20 * file descriptor passing hacked up from
21 * Mike Shaver's work.
22 * Marty Leisner : Fixes to fd passing
23 * Nick Nevin : recvmsg bugfix.
24 * Alan Cox : Started proper garbage collector
25 * Heiko EiBfeldt : Missing verify_area check
26 * Alan Cox : Started POSIXisms
27 * Andreas Schwab : Replace inode by dentry for proper
28 * reference counting
29 * Kirk Petersen : Made this a module
30 * Christoph Rohland : Elegant non-blocking accept/connect algorithm.
31 * Lots of bug fixes.
32 * Alexey Kuznetosv : Repaired (I hope) bugs introduces
33 * by above two patches.
34 * Andrea Arcangeli : If possible we block in connect(2)
35 * if the max backlog of the listen socket
36 * is been reached. This won't break
37 * old apps and it will avoid huge amount
38 * of socks hashed (this for unix_gc()
39 * performances reasons).
40 * Security fix that limits the max
41 * number of socks to 2*max_files and
42 * the number of skb queueable in the
43 * dgram receiver.
44 * Artur Skawina : Hash function optimizations
45 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
46 * Malcolm Beattie : Set peercred for socketpair
47 * Michal Ostrowski : Module initialization cleanup.
48 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT,
49 * the core infrastructure is doing that
50 * for all net proto families now (2.5.69+)
51 *
52 *
53 * Known differences from reference BSD that was tested:
54 *
55 * [TO FIX]
56 * ECONNREFUSED is not returned from one end of a connected() socket to the
57 * other the moment one end closes.
58 * fstat() doesn't return st_dev=0, and give the blksize as high water mark
59 * and a fake inode identifier (nor the BSD first socket fstat twice bug).
60 * [NOT TO FIX]
61 * accept() returns a path name even if the connecting socket has closed
62 * in the meantime (BSD loses the path and gives up).
63 * accept() returns 0 length path for an unbound connector. BSD returns 16
64 * and a null first byte in the path (but not for gethost/peername - BSD bug ??)
65 * socketpair(...SOCK_RAW..) doesn't panic the kernel.
66 * BSD af_unix apparently has connect forgetting to block properly.
67 * (need to check this with the POSIX spec in detail)
68 *
69 * Differences from 2.0.0-11-... (ANK)
70 * Bug fixes and improvements.
71 * - client shutdown killed server socket.
72 * - removed all useless cli/sti pairs.
73 *
74 * Semantic changes/extensions.
75 * - generic control message passing.
76 * - SCM_CREDENTIALS control message.
77 * - "Abstract" (not FS based) socket bindings.
78 * Abstract names are sequences of bytes (not zero terminated)
79 * started by 0, so that this name space does not intersect
80 * with BSD names.
81 */
82
83#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
84
85#include <linux/module.h>
86#include <linux/kernel.h>
87#include <linux/signal.h>
88#include <linux/sched.h>
89#include <linux/errno.h>
90#include <linux/string.h>
91#include <linux/stat.h>
92#include <linux/dcache.h>
93#include <linux/namei.h>
94#include <linux/socket.h>
95#include <linux/un.h>
96#include <linux/fcntl.h>
97#include <linux/termios.h>
98#include <linux/sockios.h>
99#include <linux/net.h>
100#include <linux/in.h>
101#include <linux/fs.h>
102#include <linux/slab.h>
103#include <asm/uaccess.h>
104#include <linux/skbuff.h>
105#include <linux/netdevice.h>
106#include <net/net_namespace.h>
107#include <net/sock.h>
108#include <net/tcp_states.h>
109#include <net/af_unix.h>
110#include <linux/proc_fs.h>
111#include <linux/seq_file.h>
112#include <net/scm.h>
113#include <linux/init.h>
114#include <linux/poll.h>
115#include <linux/rtnetlink.h>
116#include <linux/mount.h>
117#include <net/checksum.h>
118#include <linux/security.h>
119#include <linux/freezer.h>
120
121struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
122EXPORT_SYMBOL_GPL(unix_socket_table);
123DEFINE_SPINLOCK(unix_table_lock);
124EXPORT_SYMBOL_GPL(unix_table_lock);
125static atomic_long_t unix_nr_socks;
126
127
128static struct hlist_head *unix_sockets_unbound(void *addr)
129{
130 unsigned long hash = (unsigned long)addr;
131
132 hash ^= hash >> 16;
133 hash ^= hash >> 8;
134 hash %= UNIX_HASH_SIZE;
135 return &unix_socket_table[UNIX_HASH_SIZE + hash];
136}
137
138#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
139
140#ifdef CONFIG_SECURITY_NETWORK
141static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
142{
143 UNIXCB(skb).secid = scm->secid;
144}
145
146static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
147{
148 scm->secid = UNIXCB(skb).secid;
149}
150
151static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
152{
153 return (scm->secid == UNIXCB(skb).secid);
154}
155#else
156static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
157{ }
158
159static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
160{ }
161
162static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
163{
164 return true;
165}
166#endif /* CONFIG_SECURITY_NETWORK */
167
168/*
169 * SMP locking strategy:
170 * hash table is protected with spinlock unix_table_lock
171 * each socket state is protected by separate spin lock.
172 */
173
174static inline unsigned int unix_hash_fold(__wsum n)
175{
176 unsigned int hash = (__force unsigned int)csum_fold(n);
177
178 hash ^= hash>>8;
179 return hash&(UNIX_HASH_SIZE-1);
180}
181
182#define unix_peer(sk) (unix_sk(sk)->peer)
183
184static inline int unix_our_peer(struct sock *sk, struct sock *osk)
185{
186 return unix_peer(osk) == sk;
187}
188
189static inline int unix_may_send(struct sock *sk, struct sock *osk)
190{
191 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
192}
193
194static inline int unix_recvq_full(struct sock const *sk)
195{
196 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
197}
198
199struct sock *unix_peer_get(struct sock *s)
200{
201 struct sock *peer;
202
203 unix_state_lock(s);
204 peer = unix_peer(s);
205 if (peer)
206 sock_hold(peer);
207 unix_state_unlock(s);
208 return peer;
209}
210EXPORT_SYMBOL_GPL(unix_peer_get);
211
212static inline void unix_release_addr(struct unix_address *addr)
213{
214 if (atomic_dec_and_test(&addr->refcnt))
215 kfree(addr);
216}
217
218/*
219 * Check unix socket name:
220 * - should be not zero length.
221 * - if started by not zero, should be NULL terminated (FS object)
222 * - if started by zero, it is abstract name.
223 */
224
225static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
226{
227 if (len <= sizeof(short) || len > sizeof(*sunaddr))
228 return -EINVAL;
229 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
230 return -EINVAL;
231 if (sunaddr->sun_path[0]) {
232 /*
233 * This may look like an off by one error but it is a bit more
234 * subtle. 108 is the longest valid AF_UNIX path for a binding.
235 * sun_path[108] doesn't as such exist. However in kernel space
236 * we are guaranteed that it is a valid memory location in our
237 * kernel address buffer.
238 */
239 ((char *)sunaddr)[len] = 0;
240 len = strlen(sunaddr->sun_path)+1+sizeof(short);
241 return len;
242 }
243
244 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
245 return len;
246}
247
248static void __unix_remove_socket(struct sock *sk)
249{
250 sk_del_node_init(sk);
251}
252
253static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
254{
255 WARN_ON(!sk_unhashed(sk));
256 sk_add_node(sk, list);
257}
258
259static inline void unix_remove_socket(struct sock *sk)
260{
261 spin_lock(&unix_table_lock);
262 __unix_remove_socket(sk);
263 spin_unlock(&unix_table_lock);
264}
265
266static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
267{
268 spin_lock(&unix_table_lock);
269 __unix_insert_socket(list, sk);
270 spin_unlock(&unix_table_lock);
271}
272
273static struct sock *__unix_find_socket_byname(struct net *net,
274 struct sockaddr_un *sunname,
275 int len, int type, unsigned int hash)
276{
277 struct sock *s;
278
279 sk_for_each(s, &unix_socket_table[hash ^ type]) {
280 struct unix_sock *u = unix_sk(s);
281
282 if (!net_eq(sock_net(s), net))
283 continue;
284
285 if (u->addr->len == len &&
286 !memcmp(u->addr->name, sunname, len))
287 goto found;
288 }
289 s = NULL;
290found:
291 return s;
292}
293
294static inline struct sock *unix_find_socket_byname(struct net *net,
295 struct sockaddr_un *sunname,
296 int len, int type,
297 unsigned int hash)
298{
299 struct sock *s;
300
301 spin_lock(&unix_table_lock);
302 s = __unix_find_socket_byname(net, sunname, len, type, hash);
303 if (s)
304 sock_hold(s);
305 spin_unlock(&unix_table_lock);
306 return s;
307}
308
309static struct sock *unix_find_socket_byinode(struct inode *i)
310{
311 struct sock *s;
312
313 spin_lock(&unix_table_lock);
314 sk_for_each(s,
315 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
316 struct dentry *dentry = unix_sk(s)->path.dentry;
317
318 if (dentry && d_backing_inode(dentry) == i) {
319 sock_hold(s);
320 goto found;
321 }
322 }
323 s = NULL;
324found:
325 spin_unlock(&unix_table_lock);
326 return s;
327}
328
329/* Support code for asymmetrically connected dgram sockets
330 *
331 * If a datagram socket is connected to a socket not itself connected
332 * to the first socket (eg, /dev/log), clients may only enqueue more
333 * messages if the present receive queue of the server socket is not
334 * "too large". This means there's a second writeability condition
335 * poll and sendmsg need to test. The dgram recv code will do a wake
336 * up on the peer_wait wait queue of a socket upon reception of a
337 * datagram which needs to be propagated to sleeping would-be writers
338 * since these might not have sent anything so far. This can't be
339 * accomplished via poll_wait because the lifetime of the server
340 * socket might be less than that of its clients if these break their
341 * association with it or if the server socket is closed while clients
342 * are still connected to it and there's no way to inform "a polling
343 * implementation" that it should let go of a certain wait queue
344 *
345 * In order to propagate a wake up, a wait_queue_t of the client
346 * socket is enqueued on the peer_wait queue of the server socket
347 * whose wake function does a wake_up on the ordinary client socket
348 * wait queue. This connection is established whenever a write (or
349 * poll for write) hit the flow control condition and broken when the
350 * association to the server socket is dissolved or after a wake up
351 * was relayed.
352 */
353
354static int unix_dgram_peer_wake_relay(wait_queue_t *q, unsigned mode, int flags,
355 void *key)
356{
357 struct unix_sock *u;
358 wait_queue_head_t *u_sleep;
359
360 u = container_of(q, struct unix_sock, peer_wake);
361
362 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
363 q);
364 u->peer_wake.private = NULL;
365
366 /* relaying can only happen while the wq still exists */
367 u_sleep = sk_sleep(&u->sk);
368 if (u_sleep)
369 wake_up_interruptible_poll(u_sleep, key);
370
371 return 0;
372}
373
374static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
375{
376 struct unix_sock *u, *u_other;
377 int rc;
378
379 u = unix_sk(sk);
380 u_other = unix_sk(other);
381 rc = 0;
382 spin_lock(&u_other->peer_wait.lock);
383
384 if (!u->peer_wake.private) {
385 u->peer_wake.private = other;
386 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
387
388 rc = 1;
389 }
390
391 spin_unlock(&u_other->peer_wait.lock);
392 return rc;
393}
394
395static void unix_dgram_peer_wake_disconnect(struct sock *sk,
396 struct sock *other)
397{
398 struct unix_sock *u, *u_other;
399
400 u = unix_sk(sk);
401 u_other = unix_sk(other);
402 spin_lock(&u_other->peer_wait.lock);
403
404 if (u->peer_wake.private == other) {
405 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
406 u->peer_wake.private = NULL;
407 }
408
409 spin_unlock(&u_other->peer_wait.lock);
410}
411
412static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
413 struct sock *other)
414{
415 unix_dgram_peer_wake_disconnect(sk, other);
416 wake_up_interruptible_poll(sk_sleep(sk),
417 POLLOUT |
418 POLLWRNORM |
419 POLLWRBAND);
420}
421
422/* preconditions:
423 * - unix_peer(sk) == other
424 * - association is stable
425 */
426static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
427{
428 int connected;
429
430 connected = unix_dgram_peer_wake_connect(sk, other);
431
432 if (unix_recvq_full(other))
433 return 1;
434
435 if (connected)
436 unix_dgram_peer_wake_disconnect(sk, other);
437
438 return 0;
439}
440
441static int unix_writable(const struct sock *sk)
442{
443 return sk->sk_state != TCP_LISTEN &&
444 (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
445}
446
447static void unix_write_space(struct sock *sk)
448{
449 struct socket_wq *wq;
450
451 rcu_read_lock();
452 if (unix_writable(sk)) {
453 wq = rcu_dereference(sk->sk_wq);
454 if (skwq_has_sleeper(wq))
455 wake_up_interruptible_sync_poll(&wq->wait,
456 POLLOUT | POLLWRNORM | POLLWRBAND);
457 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
458 }
459 rcu_read_unlock();
460}
461
462/* When dgram socket disconnects (or changes its peer), we clear its receive
463 * queue of packets arrived from previous peer. First, it allows to do
464 * flow control based only on wmem_alloc; second, sk connected to peer
465 * may receive messages only from that peer. */
466static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
467{
468 if (!skb_queue_empty(&sk->sk_receive_queue)) {
469 skb_queue_purge(&sk->sk_receive_queue);
470 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
471
472 /* If one link of bidirectional dgram pipe is disconnected,
473 * we signal error. Messages are lost. Do not make this,
474 * when peer was not connected to us.
475 */
476 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
477 other->sk_err = ECONNRESET;
478 other->sk_error_report(other);
479 }
480 }
481}
482
483static void unix_sock_destructor(struct sock *sk)
484{
485 struct unix_sock *u = unix_sk(sk);
486
487 skb_queue_purge(&sk->sk_receive_queue);
488
489 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
490 WARN_ON(!sk_unhashed(sk));
491 WARN_ON(sk->sk_socket);
492 if (!sock_flag(sk, SOCK_DEAD)) {
493 pr_info("Attempt to release alive unix socket: %p\n", sk);
494 return;
495 }
496
497 if (u->addr)
498 unix_release_addr(u->addr);
499
500 atomic_long_dec(&unix_nr_socks);
501 local_bh_disable();
502 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
503 local_bh_enable();
504#ifdef UNIX_REFCNT_DEBUG
505 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
506 atomic_long_read(&unix_nr_socks));
507#endif
508}
509
510static void unix_release_sock(struct sock *sk, int embrion)
511{
512 struct unix_sock *u = unix_sk(sk);
513 struct path path;
514 struct sock *skpair;
515 struct sk_buff *skb;
516 int state;
517
518 unix_remove_socket(sk);
519
520 /* Clear state */
521 unix_state_lock(sk);
522 sock_orphan(sk);
523 sk->sk_shutdown = SHUTDOWN_MASK;
524 path = u->path;
525 u->path.dentry = NULL;
526 u->path.mnt = NULL;
527 state = sk->sk_state;
528 sk->sk_state = TCP_CLOSE;
529 unix_state_unlock(sk);
530
531 wake_up_interruptible_all(&u->peer_wait);
532
533 skpair = unix_peer(sk);
534
535 if (skpair != NULL) {
536 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
537 unix_state_lock(skpair);
538 /* No more writes */
539 skpair->sk_shutdown = SHUTDOWN_MASK;
540 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
541 skpair->sk_err = ECONNRESET;
542 unix_state_unlock(skpair);
543 skpair->sk_state_change(skpair);
544 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
545 }
546
547 unix_dgram_peer_wake_disconnect(sk, skpair);
548 sock_put(skpair); /* It may now die */
549 unix_peer(sk) = NULL;
550 }
551
552 /* Try to flush out this socket. Throw out buffers at least */
553
554 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
555 if (state == TCP_LISTEN)
556 unix_release_sock(skb->sk, 1);
557 /* passed fds are erased in the kfree_skb hook */
558 UNIXCB(skb).consumed = skb->len;
559 kfree_skb(skb);
560 }
561
562 if (path.dentry)
563 path_put(&path);
564
565 sock_put(sk);
566
567 /* ---- Socket is dead now and most probably destroyed ---- */
568
569 /*
570 * Fixme: BSD difference: In BSD all sockets connected to us get
571 * ECONNRESET and we die on the spot. In Linux we behave
572 * like files and pipes do and wait for the last
573 * dereference.
574 *
575 * Can't we simply set sock->err?
576 *
577 * What the above comment does talk about? --ANK(980817)
578 */
579
580 if (unix_tot_inflight)
581 unix_gc(); /* Garbage collect fds */
582}
583
584static void init_peercred(struct sock *sk)
585{
586 put_pid(sk->sk_peer_pid);
587 if (sk->sk_peer_cred)
588 put_cred(sk->sk_peer_cred);
589 sk->sk_peer_pid = get_pid(task_tgid(current));
590 sk->sk_peer_cred = get_current_cred();
591}
592
593static void copy_peercred(struct sock *sk, struct sock *peersk)
594{
595 put_pid(sk->sk_peer_pid);
596 if (sk->sk_peer_cred)
597 put_cred(sk->sk_peer_cred);
598 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
599 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
600}
601
602static int unix_listen(struct socket *sock, int backlog)
603{
604 int err;
605 struct sock *sk = sock->sk;
606 struct unix_sock *u = unix_sk(sk);
607 struct pid *old_pid = NULL;
608
609 err = -EOPNOTSUPP;
610 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
611 goto out; /* Only stream/seqpacket sockets accept */
612 err = -EINVAL;
613 if (!u->addr)
614 goto out; /* No listens on an unbound socket */
615 unix_state_lock(sk);
616 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
617 goto out_unlock;
618 if (backlog > sk->sk_max_ack_backlog)
619 wake_up_interruptible_all(&u->peer_wait);
620 sk->sk_max_ack_backlog = backlog;
621 sk->sk_state = TCP_LISTEN;
622 /* set credentials so connect can copy them */
623 init_peercred(sk);
624 err = 0;
625
626out_unlock:
627 unix_state_unlock(sk);
628 put_pid(old_pid);
629out:
630 return err;
631}
632
633static int unix_release(struct socket *);
634static int unix_bind(struct socket *, struct sockaddr *, int);
635static int unix_stream_connect(struct socket *, struct sockaddr *,
636 int addr_len, int flags);
637static int unix_socketpair(struct socket *, struct socket *);
638static int unix_accept(struct socket *, struct socket *, int);
639static int unix_getname(struct socket *, struct sockaddr *, int *, int);
640static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
641static unsigned int unix_dgram_poll(struct file *, struct socket *,
642 poll_table *);
643static int unix_ioctl(struct socket *, unsigned int, unsigned long);
644static int unix_shutdown(struct socket *, int);
645static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
646static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
647static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
648 size_t size, int flags);
649static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
650 struct pipe_inode_info *, size_t size,
651 unsigned int flags);
652static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
653static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
654static int unix_dgram_connect(struct socket *, struct sockaddr *,
655 int, int);
656static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
657static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
658 int);
659
660static int unix_set_peek_off(struct sock *sk, int val)
661{
662 struct unix_sock *u = unix_sk(sk);
663
664 if (mutex_lock_interruptible(&u->readlock))
665 return -EINTR;
666
667 sk->sk_peek_off = val;
668 mutex_unlock(&u->readlock);
669
670 return 0;
671}
672
673
674static const struct proto_ops unix_stream_ops = {
675 .family = PF_UNIX,
676 .owner = THIS_MODULE,
677 .release = unix_release,
678 .bind = unix_bind,
679 .connect = unix_stream_connect,
680 .socketpair = unix_socketpair,
681 .accept = unix_accept,
682 .getname = unix_getname,
683 .poll = unix_poll,
684 .ioctl = unix_ioctl,
685 .listen = unix_listen,
686 .shutdown = unix_shutdown,
687 .setsockopt = sock_no_setsockopt,
688 .getsockopt = sock_no_getsockopt,
689 .sendmsg = unix_stream_sendmsg,
690 .recvmsg = unix_stream_recvmsg,
691 .mmap = sock_no_mmap,
692 .sendpage = unix_stream_sendpage,
693 .splice_read = unix_stream_splice_read,
694 .set_peek_off = unix_set_peek_off,
695};
696
697static const struct proto_ops unix_dgram_ops = {
698 .family = PF_UNIX,
699 .owner = THIS_MODULE,
700 .release = unix_release,
701 .bind = unix_bind,
702 .connect = unix_dgram_connect,
703 .socketpair = unix_socketpair,
704 .accept = sock_no_accept,
705 .getname = unix_getname,
706 .poll = unix_dgram_poll,
707 .ioctl = unix_ioctl,
708 .listen = sock_no_listen,
709 .shutdown = unix_shutdown,
710 .setsockopt = sock_no_setsockopt,
711 .getsockopt = sock_no_getsockopt,
712 .sendmsg = unix_dgram_sendmsg,
713 .recvmsg = unix_dgram_recvmsg,
714 .mmap = sock_no_mmap,
715 .sendpage = sock_no_sendpage,
716 .set_peek_off = unix_set_peek_off,
717};
718
719static const struct proto_ops unix_seqpacket_ops = {
720 .family = PF_UNIX,
721 .owner = THIS_MODULE,
722 .release = unix_release,
723 .bind = unix_bind,
724 .connect = unix_stream_connect,
725 .socketpair = unix_socketpair,
726 .accept = unix_accept,
727 .getname = unix_getname,
728 .poll = unix_dgram_poll,
729 .ioctl = unix_ioctl,
730 .listen = unix_listen,
731 .shutdown = unix_shutdown,
732 .setsockopt = sock_no_setsockopt,
733 .getsockopt = sock_no_getsockopt,
734 .sendmsg = unix_seqpacket_sendmsg,
735 .recvmsg = unix_seqpacket_recvmsg,
736 .mmap = sock_no_mmap,
737 .sendpage = sock_no_sendpage,
738 .set_peek_off = unix_set_peek_off,
739};
740
741static struct proto unix_proto = {
742 .name = "UNIX",
743 .owner = THIS_MODULE,
744 .obj_size = sizeof(struct unix_sock),
745};
746
747/*
748 * AF_UNIX sockets do not interact with hardware, hence they
749 * dont trigger interrupts - so it's safe for them to have
750 * bh-unsafe locking for their sk_receive_queue.lock. Split off
751 * this special lock-class by reinitializing the spinlock key:
752 */
753static struct lock_class_key af_unix_sk_receive_queue_lock_key;
754
755static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
756{
757 struct sock *sk = NULL;
758 struct unix_sock *u;
759
760 atomic_long_inc(&unix_nr_socks);
761 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
762 goto out;
763
764 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
765 if (!sk)
766 goto out;
767
768 sock_init_data(sock, sk);
769 lockdep_set_class(&sk->sk_receive_queue.lock,
770 &af_unix_sk_receive_queue_lock_key);
771
772 sk->sk_write_space = unix_write_space;
773 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
774 sk->sk_destruct = unix_sock_destructor;
775 u = unix_sk(sk);
776 u->path.dentry = NULL;
777 u->path.mnt = NULL;
778 spin_lock_init(&u->lock);
779 atomic_long_set(&u->inflight, 0);
780 INIT_LIST_HEAD(&u->link);
781 mutex_init(&u->readlock); /* single task reading lock */
782 init_waitqueue_head(&u->peer_wait);
783 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
784 unix_insert_socket(unix_sockets_unbound(sk), sk);
785out:
786 if (sk == NULL)
787 atomic_long_dec(&unix_nr_socks);
788 else {
789 local_bh_disable();
790 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
791 local_bh_enable();
792 }
793 return sk;
794}
795
796static int unix_create(struct net *net, struct socket *sock, int protocol,
797 int kern)
798{
799 if (protocol && protocol != PF_UNIX)
800 return -EPROTONOSUPPORT;
801
802 sock->state = SS_UNCONNECTED;
803
804 switch (sock->type) {
805 case SOCK_STREAM:
806 sock->ops = &unix_stream_ops;
807 break;
808 /*
809 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
810 * nothing uses it.
811 */
812 case SOCK_RAW:
813 sock->type = SOCK_DGRAM;
814 case SOCK_DGRAM:
815 sock->ops = &unix_dgram_ops;
816 break;
817 case SOCK_SEQPACKET:
818 sock->ops = &unix_seqpacket_ops;
819 break;
820 default:
821 return -ESOCKTNOSUPPORT;
822 }
823
824 return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
825}
826
827static int unix_release(struct socket *sock)
828{
829 struct sock *sk = sock->sk;
830
831 if (!sk)
832 return 0;
833
834 unix_release_sock(sk, 0);
835 sock->sk = NULL;
836
837 return 0;
838}
839
840static int unix_autobind(struct socket *sock)
841{
842 struct sock *sk = sock->sk;
843 struct net *net = sock_net(sk);
844 struct unix_sock *u = unix_sk(sk);
845 static u32 ordernum = 1;
846 struct unix_address *addr;
847 int err;
848 unsigned int retries = 0;
849
850 err = mutex_lock_interruptible(&u->readlock);
851 if (err)
852 return err;
853
854 err = 0;
855 if (u->addr)
856 goto out;
857
858 err = -ENOMEM;
859 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
860 if (!addr)
861 goto out;
862
863 addr->name->sun_family = AF_UNIX;
864 atomic_set(&addr->refcnt, 1);
865
866retry:
867 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
868 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
869
870 spin_lock(&unix_table_lock);
871 ordernum = (ordernum+1)&0xFFFFF;
872
873 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
874 addr->hash)) {
875 spin_unlock(&unix_table_lock);
876 /*
877 * __unix_find_socket_byname() may take long time if many names
878 * are already in use.
879 */
880 cond_resched();
881 /* Give up if all names seems to be in use. */
882 if (retries++ == 0xFFFFF) {
883 err = -ENOSPC;
884 kfree(addr);
885 goto out;
886 }
887 goto retry;
888 }
889 addr->hash ^= sk->sk_type;
890
891 __unix_remove_socket(sk);
892 u->addr = addr;
893 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
894 spin_unlock(&unix_table_lock);
895 err = 0;
896
897out: mutex_unlock(&u->readlock);
898 return err;
899}
900
901static struct sock *unix_find_other(struct net *net,
902 struct sockaddr_un *sunname, int len,
903 int type, unsigned int hash, int *error)
904{
905 struct sock *u;
906 struct path path;
907 int err = 0;
908
909 if (sunname->sun_path[0]) {
910 struct inode *inode;
911 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
912 if (err)
913 goto fail;
914 inode = d_backing_inode(path.dentry);
915 err = inode_permission(inode, MAY_WRITE);
916 if (err)
917 goto put_fail;
918
919 err = -ECONNREFUSED;
920 if (!S_ISSOCK(inode->i_mode))
921 goto put_fail;
922 u = unix_find_socket_byinode(inode);
923 if (!u)
924 goto put_fail;
925
926 if (u->sk_type == type)
927 touch_atime(&path);
928
929 path_put(&path);
930
931 err = -EPROTOTYPE;
932 if (u->sk_type != type) {
933 sock_put(u);
934 goto fail;
935 }
936 } else {
937 err = -ECONNREFUSED;
938 u = unix_find_socket_byname(net, sunname, len, type, hash);
939 if (u) {
940 struct dentry *dentry;
941 dentry = unix_sk(u)->path.dentry;
942 if (dentry)
943 touch_atime(&unix_sk(u)->path);
944 } else
945 goto fail;
946 }
947 return u;
948
949put_fail:
950 path_put(&path);
951fail:
952 *error = err;
953 return NULL;
954}
955
956static int unix_mknod(struct dentry *dentry, struct path *path, umode_t mode,
957 struct path *res)
958{
959 int err;
960
961 err = security_path_mknod(path, dentry, mode, 0);
962 if (!err) {
963 err = vfs_mknod(d_inode(path->dentry), dentry, mode, 0);
964 if (!err) {
965 res->mnt = mntget(path->mnt);
966 res->dentry = dget(dentry);
967 }
968 }
969
970 return err;
971}
972
973static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
974{
975 struct sock *sk = sock->sk;
976 struct net *net = sock_net(sk);
977 struct unix_sock *u = unix_sk(sk);
978 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
979 char *sun_path = sunaddr->sun_path;
980 int err, name_err;
981 unsigned int hash;
982 struct unix_address *addr;
983 struct hlist_head *list;
984 struct path path;
985 struct dentry *dentry;
986
987 err = -EINVAL;
988 if (sunaddr->sun_family != AF_UNIX)
989 goto out;
990
991 if (addr_len == sizeof(short)) {
992 err = unix_autobind(sock);
993 goto out;
994 }
995
996 err = unix_mkname(sunaddr, addr_len, &hash);
997 if (err < 0)
998 goto out;
999 addr_len = err;
1000
1001 name_err = 0;
1002 dentry = NULL;
1003 if (sun_path[0]) {
1004 /* Get the parent directory, calculate the hash for last
1005 * component.
1006 */
1007 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
1008
1009 if (IS_ERR(dentry)) {
1010 /* delay report until after 'already bound' check */
1011 name_err = PTR_ERR(dentry);
1012 dentry = NULL;
1013 }
1014 }
1015
1016 err = mutex_lock_interruptible(&u->readlock);
1017 if (err)
1018 goto out_path;
1019
1020 err = -EINVAL;
1021 if (u->addr)
1022 goto out_up;
1023
1024 if (name_err) {
1025 err = name_err == -EEXIST ? -EADDRINUSE : name_err;
1026 goto out_up;
1027 }
1028
1029 err = -ENOMEM;
1030 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
1031 if (!addr)
1032 goto out_up;
1033
1034 memcpy(addr->name, sunaddr, addr_len);
1035 addr->len = addr_len;
1036 addr->hash = hash ^ sk->sk_type;
1037 atomic_set(&addr->refcnt, 1);
1038
1039 if (dentry) {
1040 struct path u_path;
1041 umode_t mode = S_IFSOCK |
1042 (SOCK_INODE(sock)->i_mode & ~current_umask());
1043 err = unix_mknod(dentry, &path, mode, &u_path);
1044 if (err) {
1045 if (err == -EEXIST)
1046 err = -EADDRINUSE;
1047 unix_release_addr(addr);
1048 goto out_up;
1049 }
1050 addr->hash = UNIX_HASH_SIZE;
1051 hash = d_backing_inode(dentry)->i_ino & (UNIX_HASH_SIZE - 1);
1052 spin_lock(&unix_table_lock);
1053 u->path = u_path;
1054 list = &unix_socket_table[hash];
1055 } else {
1056 spin_lock(&unix_table_lock);
1057 err = -EADDRINUSE;
1058 if (__unix_find_socket_byname(net, sunaddr, addr_len,
1059 sk->sk_type, hash)) {
1060 unix_release_addr(addr);
1061 goto out_unlock;
1062 }
1063
1064 list = &unix_socket_table[addr->hash];
1065 }
1066
1067 err = 0;
1068 __unix_remove_socket(sk);
1069 u->addr = addr;
1070 __unix_insert_socket(list, sk);
1071
1072out_unlock:
1073 spin_unlock(&unix_table_lock);
1074out_up:
1075 mutex_unlock(&u->readlock);
1076out_path:
1077 if (dentry)
1078 done_path_create(&path, dentry);
1079
1080out:
1081 return err;
1082}
1083
1084static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1085{
1086 if (unlikely(sk1 == sk2) || !sk2) {
1087 unix_state_lock(sk1);
1088 return;
1089 }
1090 if (sk1 < sk2) {
1091 unix_state_lock(sk1);
1092 unix_state_lock_nested(sk2);
1093 } else {
1094 unix_state_lock(sk2);
1095 unix_state_lock_nested(sk1);
1096 }
1097}
1098
1099static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1100{
1101 if (unlikely(sk1 == sk2) || !sk2) {
1102 unix_state_unlock(sk1);
1103 return;
1104 }
1105 unix_state_unlock(sk1);
1106 unix_state_unlock(sk2);
1107}
1108
1109static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1110 int alen, int flags)
1111{
1112 struct sock *sk = sock->sk;
1113 struct net *net = sock_net(sk);
1114 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1115 struct sock *other;
1116 unsigned int hash;
1117 int err;
1118
1119 if (addr->sa_family != AF_UNSPEC) {
1120 err = unix_mkname(sunaddr, alen, &hash);
1121 if (err < 0)
1122 goto out;
1123 alen = err;
1124
1125 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1126 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1127 goto out;
1128
1129restart:
1130 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1131 if (!other)
1132 goto out;
1133
1134 unix_state_double_lock(sk, other);
1135
1136 /* Apparently VFS overslept socket death. Retry. */
1137 if (sock_flag(other, SOCK_DEAD)) {
1138 unix_state_double_unlock(sk, other);
1139 sock_put(other);
1140 goto restart;
1141 }
1142
1143 err = -EPERM;
1144 if (!unix_may_send(sk, other))
1145 goto out_unlock;
1146
1147 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1148 if (err)
1149 goto out_unlock;
1150
1151 } else {
1152 /*
1153 * 1003.1g breaking connected state with AF_UNSPEC
1154 */
1155 other = NULL;
1156 unix_state_double_lock(sk, other);
1157 }
1158
1159 /*
1160 * If it was connected, reconnect.
1161 */
1162 if (unix_peer(sk)) {
1163 struct sock *old_peer = unix_peer(sk);
1164 unix_peer(sk) = other;
1165 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1166
1167 unix_state_double_unlock(sk, other);
1168
1169 if (other != old_peer)
1170 unix_dgram_disconnected(sk, old_peer);
1171 sock_put(old_peer);
1172 } else {
1173 unix_peer(sk) = other;
1174 unix_state_double_unlock(sk, other);
1175 }
1176 return 0;
1177
1178out_unlock:
1179 unix_state_double_unlock(sk, other);
1180 sock_put(other);
1181out:
1182 return err;
1183}
1184
1185static long unix_wait_for_peer(struct sock *other, long timeo)
1186{
1187 struct unix_sock *u = unix_sk(other);
1188 int sched;
1189 DEFINE_WAIT(wait);
1190
1191 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1192
1193 sched = !sock_flag(other, SOCK_DEAD) &&
1194 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1195 unix_recvq_full(other);
1196
1197 unix_state_unlock(other);
1198
1199 if (sched)
1200 timeo = schedule_timeout(timeo);
1201
1202 finish_wait(&u->peer_wait, &wait);
1203 return timeo;
1204}
1205
1206static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1207 int addr_len, int flags)
1208{
1209 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1210 struct sock *sk = sock->sk;
1211 struct net *net = sock_net(sk);
1212 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1213 struct sock *newsk = NULL;
1214 struct sock *other = NULL;
1215 struct sk_buff *skb = NULL;
1216 unsigned int hash;
1217 int st;
1218 int err;
1219 long timeo;
1220
1221 err = unix_mkname(sunaddr, addr_len, &hash);
1222 if (err < 0)
1223 goto out;
1224 addr_len = err;
1225
1226 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1227 (err = unix_autobind(sock)) != 0)
1228 goto out;
1229
1230 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1231
1232 /* First of all allocate resources.
1233 If we will make it after state is locked,
1234 we will have to recheck all again in any case.
1235 */
1236
1237 err = -ENOMEM;
1238
1239 /* create new sock for complete connection */
1240 newsk = unix_create1(sock_net(sk), NULL, 0);
1241 if (newsk == NULL)
1242 goto out;
1243
1244 /* Allocate skb for sending to listening sock */
1245 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1246 if (skb == NULL)
1247 goto out;
1248
1249restart:
1250 /* Find listening sock. */
1251 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1252 if (!other)
1253 goto out;
1254
1255 /* Latch state of peer */
1256 unix_state_lock(other);
1257
1258 /* Apparently VFS overslept socket death. Retry. */
1259 if (sock_flag(other, SOCK_DEAD)) {
1260 unix_state_unlock(other);
1261 sock_put(other);
1262 goto restart;
1263 }
1264
1265 err = -ECONNREFUSED;
1266 if (other->sk_state != TCP_LISTEN)
1267 goto out_unlock;
1268 if (other->sk_shutdown & RCV_SHUTDOWN)
1269 goto out_unlock;
1270
1271 if (unix_recvq_full(other)) {
1272 err = -EAGAIN;
1273 if (!timeo)
1274 goto out_unlock;
1275
1276 timeo = unix_wait_for_peer(other, timeo);
1277
1278 err = sock_intr_errno(timeo);
1279 if (signal_pending(current))
1280 goto out;
1281 sock_put(other);
1282 goto restart;
1283 }
1284
1285 /* Latch our state.
1286
1287 It is tricky place. We need to grab our state lock and cannot
1288 drop lock on peer. It is dangerous because deadlock is
1289 possible. Connect to self case and simultaneous
1290 attempt to connect are eliminated by checking socket
1291 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1292 check this before attempt to grab lock.
1293
1294 Well, and we have to recheck the state after socket locked.
1295 */
1296 st = sk->sk_state;
1297
1298 switch (st) {
1299 case TCP_CLOSE:
1300 /* This is ok... continue with connect */
1301 break;
1302 case TCP_ESTABLISHED:
1303 /* Socket is already connected */
1304 err = -EISCONN;
1305 goto out_unlock;
1306 default:
1307 err = -EINVAL;
1308 goto out_unlock;
1309 }
1310
1311 unix_state_lock_nested(sk);
1312
1313 if (sk->sk_state != st) {
1314 unix_state_unlock(sk);
1315 unix_state_unlock(other);
1316 sock_put(other);
1317 goto restart;
1318 }
1319
1320 err = security_unix_stream_connect(sk, other, newsk);
1321 if (err) {
1322 unix_state_unlock(sk);
1323 goto out_unlock;
1324 }
1325
1326 /* The way is open! Fastly set all the necessary fields... */
1327
1328 sock_hold(sk);
1329 unix_peer(newsk) = sk;
1330 newsk->sk_state = TCP_ESTABLISHED;
1331 newsk->sk_type = sk->sk_type;
1332 init_peercred(newsk);
1333 newu = unix_sk(newsk);
1334 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1335 otheru = unix_sk(other);
1336
1337 /* copy address information from listening to new sock*/
1338 if (otheru->addr) {
1339 atomic_inc(&otheru->addr->refcnt);
1340 newu->addr = otheru->addr;
1341 }
1342 if (otheru->path.dentry) {
1343 path_get(&otheru->path);
1344 newu->path = otheru->path;
1345 }
1346
1347 /* Set credentials */
1348 copy_peercred(sk, other);
1349
1350 sock->state = SS_CONNECTED;
1351 sk->sk_state = TCP_ESTABLISHED;
1352 sock_hold(newsk);
1353
1354 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1355 unix_peer(sk) = newsk;
1356
1357 unix_state_unlock(sk);
1358
1359 /* take ten and and send info to listening sock */
1360 spin_lock(&other->sk_receive_queue.lock);
1361 __skb_queue_tail(&other->sk_receive_queue, skb);
1362 spin_unlock(&other->sk_receive_queue.lock);
1363 unix_state_unlock(other);
1364 other->sk_data_ready(other);
1365 sock_put(other);
1366 return 0;
1367
1368out_unlock:
1369 if (other)
1370 unix_state_unlock(other);
1371
1372out:
1373 kfree_skb(skb);
1374 if (newsk)
1375 unix_release_sock(newsk, 0);
1376 if (other)
1377 sock_put(other);
1378 return err;
1379}
1380
1381static int unix_socketpair(struct socket *socka, struct socket *sockb)
1382{
1383 struct sock *ska = socka->sk, *skb = sockb->sk;
1384
1385 /* Join our sockets back to back */
1386 sock_hold(ska);
1387 sock_hold(skb);
1388 unix_peer(ska) = skb;
1389 unix_peer(skb) = ska;
1390 init_peercred(ska);
1391 init_peercred(skb);
1392
1393 if (ska->sk_type != SOCK_DGRAM) {
1394 ska->sk_state = TCP_ESTABLISHED;
1395 skb->sk_state = TCP_ESTABLISHED;
1396 socka->state = SS_CONNECTED;
1397 sockb->state = SS_CONNECTED;
1398 }
1399 return 0;
1400}
1401
1402static void unix_sock_inherit_flags(const struct socket *old,
1403 struct socket *new)
1404{
1405 if (test_bit(SOCK_PASSCRED, &old->flags))
1406 set_bit(SOCK_PASSCRED, &new->flags);
1407 if (test_bit(SOCK_PASSSEC, &old->flags))
1408 set_bit(SOCK_PASSSEC, &new->flags);
1409}
1410
1411static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1412{
1413 struct sock *sk = sock->sk;
1414 struct sock *tsk;
1415 struct sk_buff *skb;
1416 int err;
1417
1418 err = -EOPNOTSUPP;
1419 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1420 goto out;
1421
1422 err = -EINVAL;
1423 if (sk->sk_state != TCP_LISTEN)
1424 goto out;
1425
1426 /* If socket state is TCP_LISTEN it cannot change (for now...),
1427 * so that no locks are necessary.
1428 */
1429
1430 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1431 if (!skb) {
1432 /* This means receive shutdown. */
1433 if (err == 0)
1434 err = -EINVAL;
1435 goto out;
1436 }
1437
1438 tsk = skb->sk;
1439 skb_free_datagram(sk, skb);
1440 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1441
1442 /* attach accepted sock to socket */
1443 unix_state_lock(tsk);
1444 newsock->state = SS_CONNECTED;
1445 unix_sock_inherit_flags(sock, newsock);
1446 sock_graft(tsk, newsock);
1447 unix_state_unlock(tsk);
1448 return 0;
1449
1450out:
1451 return err;
1452}
1453
1454
1455static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1456{
1457 struct sock *sk = sock->sk;
1458 struct unix_sock *u;
1459 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1460 int err = 0;
1461
1462 if (peer) {
1463 sk = unix_peer_get(sk);
1464
1465 err = -ENOTCONN;
1466 if (!sk)
1467 goto out;
1468 err = 0;
1469 } else {
1470 sock_hold(sk);
1471 }
1472
1473 u = unix_sk(sk);
1474 unix_state_lock(sk);
1475 if (!u->addr) {
1476 sunaddr->sun_family = AF_UNIX;
1477 sunaddr->sun_path[0] = 0;
1478 *uaddr_len = sizeof(short);
1479 } else {
1480 struct unix_address *addr = u->addr;
1481
1482 *uaddr_len = addr->len;
1483 memcpy(sunaddr, addr->name, *uaddr_len);
1484 }
1485 unix_state_unlock(sk);
1486 sock_put(sk);
1487out:
1488 return err;
1489}
1490
1491static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1492{
1493 int i;
1494
1495 scm->fp = UNIXCB(skb).fp;
1496 UNIXCB(skb).fp = NULL;
1497
1498 for (i = scm->fp->count-1; i >= 0; i--)
1499 unix_notinflight(scm->fp->user, scm->fp->fp[i]);
1500}
1501
1502static void unix_destruct_scm(struct sk_buff *skb)
1503{
1504 struct scm_cookie scm;
1505 memset(&scm, 0, sizeof(scm));
1506 scm.pid = UNIXCB(skb).pid;
1507 if (UNIXCB(skb).fp)
1508 unix_detach_fds(&scm, skb);
1509
1510 /* Alas, it calls VFS */
1511 /* So fscking what? fput() had been SMP-safe since the last Summer */
1512 scm_destroy(&scm);
1513 sock_wfree(skb);
1514}
1515
1516/*
1517 * The "user->unix_inflight" variable is protected by the garbage
1518 * collection lock, and we just read it locklessly here. If you go
1519 * over the limit, there might be a tiny race in actually noticing
1520 * it across threads. Tough.
1521 */
1522static inline bool too_many_unix_fds(struct task_struct *p)
1523{
1524 struct user_struct *user = current_user();
1525
1526 if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
1527 return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1528 return false;
1529}
1530
1531#define MAX_RECURSION_LEVEL 4
1532
1533static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1534{
1535 int i;
1536 unsigned char max_level = 0;
1537
1538 if (too_many_unix_fds(current))
1539 return -ETOOMANYREFS;
1540
1541 for (i = scm->fp->count - 1; i >= 0; i--) {
1542 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1543
1544 if (sk)
1545 max_level = max(max_level,
1546 unix_sk(sk)->recursion_level);
1547 }
1548 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1549 return -ETOOMANYREFS;
1550
1551 /*
1552 * Need to duplicate file references for the sake of garbage
1553 * collection. Otherwise a socket in the fps might become a
1554 * candidate for GC while the skb is not yet queued.
1555 */
1556 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1557 if (!UNIXCB(skb).fp)
1558 return -ENOMEM;
1559
1560 for (i = scm->fp->count - 1; i >= 0; i--)
1561 unix_inflight(scm->fp->user, scm->fp->fp[i]);
1562 return max_level;
1563}
1564
1565static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1566{
1567 int err = 0;
1568
1569 UNIXCB(skb).pid = get_pid(scm->pid);
1570 UNIXCB(skb).uid = scm->creds.uid;
1571 UNIXCB(skb).gid = scm->creds.gid;
1572 UNIXCB(skb).fp = NULL;
1573 unix_get_secdata(scm, skb);
1574 if (scm->fp && send_fds)
1575 err = unix_attach_fds(scm, skb);
1576
1577 skb->destructor = unix_destruct_scm;
1578 return err;
1579}
1580
1581static bool unix_passcred_enabled(const struct socket *sock,
1582 const struct sock *other)
1583{
1584 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1585 !other->sk_socket ||
1586 test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1587}
1588
1589/*
1590 * Some apps rely on write() giving SCM_CREDENTIALS
1591 * We include credentials if source or destination socket
1592 * asserted SOCK_PASSCRED.
1593 */
1594static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1595 const struct sock *other)
1596{
1597 if (UNIXCB(skb).pid)
1598 return;
1599 if (unix_passcred_enabled(sock, other)) {
1600 UNIXCB(skb).pid = get_pid(task_tgid(current));
1601 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1602 }
1603}
1604
1605static int maybe_init_creds(struct scm_cookie *scm,
1606 struct socket *socket,
1607 const struct sock *other)
1608{
1609 int err;
1610 struct msghdr msg = { .msg_controllen = 0 };
1611
1612 err = scm_send(socket, &msg, scm, false);
1613 if (err)
1614 return err;
1615
1616 if (unix_passcred_enabled(socket, other)) {
1617 scm->pid = get_pid(task_tgid(current));
1618 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1619 }
1620 return err;
1621}
1622
1623static bool unix_skb_scm_eq(struct sk_buff *skb,
1624 struct scm_cookie *scm)
1625{
1626 const struct unix_skb_parms *u = &UNIXCB(skb);
1627
1628 return u->pid == scm->pid &&
1629 uid_eq(u->uid, scm->creds.uid) &&
1630 gid_eq(u->gid, scm->creds.gid) &&
1631 unix_secdata_eq(scm, skb);
1632}
1633
1634/*
1635 * Send AF_UNIX data.
1636 */
1637
1638static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1639 size_t len)
1640{
1641 struct sock *sk = sock->sk;
1642 struct net *net = sock_net(sk);
1643 struct unix_sock *u = unix_sk(sk);
1644 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1645 struct sock *other = NULL;
1646 int namelen = 0; /* fake GCC */
1647 int err;
1648 unsigned int hash;
1649 struct sk_buff *skb;
1650 long timeo;
1651 struct scm_cookie scm;
1652 int max_level;
1653 int data_len = 0;
1654 int sk_locked;
1655
1656 wait_for_unix_gc();
1657 err = scm_send(sock, msg, &scm, false);
1658 if (err < 0)
1659 return err;
1660
1661 err = -EOPNOTSUPP;
1662 if (msg->msg_flags&MSG_OOB)
1663 goto out;
1664
1665 if (msg->msg_namelen) {
1666 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1667 if (err < 0)
1668 goto out;
1669 namelen = err;
1670 } else {
1671 sunaddr = NULL;
1672 err = -ENOTCONN;
1673 other = unix_peer_get(sk);
1674 if (!other)
1675 goto out;
1676 }
1677
1678 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1679 && (err = unix_autobind(sock)) != 0)
1680 goto out;
1681
1682 err = -EMSGSIZE;
1683 if (len > sk->sk_sndbuf - 32)
1684 goto out;
1685
1686 if (len > SKB_MAX_ALLOC) {
1687 data_len = min_t(size_t,
1688 len - SKB_MAX_ALLOC,
1689 MAX_SKB_FRAGS * PAGE_SIZE);
1690 data_len = PAGE_ALIGN(data_len);
1691
1692 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1693 }
1694
1695 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1696 msg->msg_flags & MSG_DONTWAIT, &err,
1697 PAGE_ALLOC_COSTLY_ORDER);
1698 if (skb == NULL)
1699 goto out;
1700
1701 err = unix_scm_to_skb(&scm, skb, true);
1702 if (err < 0)
1703 goto out_free;
1704 max_level = err + 1;
1705
1706 skb_put(skb, len - data_len);
1707 skb->data_len = data_len;
1708 skb->len = len;
1709 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1710 if (err)
1711 goto out_free;
1712
1713 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1714
1715restart:
1716 if (!other) {
1717 err = -ECONNRESET;
1718 if (sunaddr == NULL)
1719 goto out_free;
1720
1721 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1722 hash, &err);
1723 if (other == NULL)
1724 goto out_free;
1725 }
1726
1727 if (sk_filter(other, skb) < 0) {
1728 /* Toss the packet but do not return any error to the sender */
1729 err = len;
1730 goto out_free;
1731 }
1732
1733 sk_locked = 0;
1734 unix_state_lock(other);
1735restart_locked:
1736 err = -EPERM;
1737 if (!unix_may_send(sk, other))
1738 goto out_unlock;
1739
1740 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1741 /*
1742 * Check with 1003.1g - what should
1743 * datagram error
1744 */
1745 unix_state_unlock(other);
1746 sock_put(other);
1747
1748 if (!sk_locked)
1749 unix_state_lock(sk);
1750
1751 err = 0;
1752 if (unix_peer(sk) == other) {
1753 unix_peer(sk) = NULL;
1754 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1755
1756 unix_state_unlock(sk);
1757
1758 unix_dgram_disconnected(sk, other);
1759 sock_put(other);
1760 err = -ECONNREFUSED;
1761 } else {
1762 unix_state_unlock(sk);
1763 }
1764
1765 other = NULL;
1766 if (err)
1767 goto out_free;
1768 goto restart;
1769 }
1770
1771 err = -EPIPE;
1772 if (other->sk_shutdown & RCV_SHUTDOWN)
1773 goto out_unlock;
1774
1775 if (sk->sk_type != SOCK_SEQPACKET) {
1776 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1777 if (err)
1778 goto out_unlock;
1779 }
1780
1781 /* other == sk && unix_peer(other) != sk if
1782 * - unix_peer(sk) == NULL, destination address bound to sk
1783 * - unix_peer(sk) == sk by time of get but disconnected before lock
1784 */
1785 if (other != sk &&
1786 unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1787 if (timeo) {
1788 timeo = unix_wait_for_peer(other, timeo);
1789
1790 err = sock_intr_errno(timeo);
1791 if (signal_pending(current))
1792 goto out_free;
1793
1794 goto restart;
1795 }
1796
1797 if (!sk_locked) {
1798 unix_state_unlock(other);
1799 unix_state_double_lock(sk, other);
1800 }
1801
1802 if (unix_peer(sk) != other ||
1803 unix_dgram_peer_wake_me(sk, other)) {
1804 err = -EAGAIN;
1805 sk_locked = 1;
1806 goto out_unlock;
1807 }
1808
1809 if (!sk_locked) {
1810 sk_locked = 1;
1811 goto restart_locked;
1812 }
1813 }
1814
1815 if (unlikely(sk_locked))
1816 unix_state_unlock(sk);
1817
1818 if (sock_flag(other, SOCK_RCVTSTAMP))
1819 __net_timestamp(skb);
1820 maybe_add_creds(skb, sock, other);
1821 skb_queue_tail(&other->sk_receive_queue, skb);
1822 if (max_level > unix_sk(other)->recursion_level)
1823 unix_sk(other)->recursion_level = max_level;
1824 unix_state_unlock(other);
1825 other->sk_data_ready(other);
1826 sock_put(other);
1827 scm_destroy(&scm);
1828 return len;
1829
1830out_unlock:
1831 if (sk_locked)
1832 unix_state_unlock(sk);
1833 unix_state_unlock(other);
1834out_free:
1835 kfree_skb(skb);
1836out:
1837 if (other)
1838 sock_put(other);
1839 scm_destroy(&scm);
1840 return err;
1841}
1842
1843/* We use paged skbs for stream sockets, and limit occupancy to 32768
1844 * bytes, and a minimun of a full page.
1845 */
1846#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1847
1848static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
1849 size_t len)
1850{
1851 struct sock *sk = sock->sk;
1852 struct sock *other = NULL;
1853 int err, size;
1854 struct sk_buff *skb;
1855 int sent = 0;
1856 struct scm_cookie scm;
1857 bool fds_sent = false;
1858 int max_level;
1859 int data_len;
1860
1861 wait_for_unix_gc();
1862 err = scm_send(sock, msg, &scm, false);
1863 if (err < 0)
1864 return err;
1865
1866 err = -EOPNOTSUPP;
1867 if (msg->msg_flags&MSG_OOB)
1868 goto out_err;
1869
1870 if (msg->msg_namelen) {
1871 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1872 goto out_err;
1873 } else {
1874 err = -ENOTCONN;
1875 other = unix_peer(sk);
1876 if (!other)
1877 goto out_err;
1878 }
1879
1880 if (sk->sk_shutdown & SEND_SHUTDOWN)
1881 goto pipe_err;
1882
1883 while (sent < len) {
1884 size = len - sent;
1885
1886 /* Keep two messages in the pipe so it schedules better */
1887 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1888
1889 /* allow fallback to order-0 allocations */
1890 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1891
1892 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1893
1894 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
1895
1896 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1897 msg->msg_flags & MSG_DONTWAIT, &err,
1898 get_order(UNIX_SKB_FRAGS_SZ));
1899 if (!skb)
1900 goto out_err;
1901
1902 /* Only send the fds in the first buffer */
1903 err = unix_scm_to_skb(&scm, skb, !fds_sent);
1904 if (err < 0) {
1905 kfree_skb(skb);
1906 goto out_err;
1907 }
1908 max_level = err + 1;
1909 fds_sent = true;
1910
1911 skb_put(skb, size - data_len);
1912 skb->data_len = data_len;
1913 skb->len = size;
1914 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
1915 if (err) {
1916 kfree_skb(skb);
1917 goto out_err;
1918 }
1919
1920 unix_state_lock(other);
1921
1922 if (sock_flag(other, SOCK_DEAD) ||
1923 (other->sk_shutdown & RCV_SHUTDOWN))
1924 goto pipe_err_free;
1925
1926 maybe_add_creds(skb, sock, other);
1927 skb_queue_tail(&other->sk_receive_queue, skb);
1928 if (max_level > unix_sk(other)->recursion_level)
1929 unix_sk(other)->recursion_level = max_level;
1930 unix_state_unlock(other);
1931 other->sk_data_ready(other);
1932 sent += size;
1933 }
1934
1935 scm_destroy(&scm);
1936
1937 return sent;
1938
1939pipe_err_free:
1940 unix_state_unlock(other);
1941 kfree_skb(skb);
1942pipe_err:
1943 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1944 send_sig(SIGPIPE, current, 0);
1945 err = -EPIPE;
1946out_err:
1947 scm_destroy(&scm);
1948 return sent ? : err;
1949}
1950
1951static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
1952 int offset, size_t size, int flags)
1953{
1954 int err;
1955 bool send_sigpipe = false;
1956 bool init_scm = true;
1957 struct scm_cookie scm;
1958 struct sock *other, *sk = socket->sk;
1959 struct sk_buff *skb, *newskb = NULL, *tail = NULL;
1960
1961 if (flags & MSG_OOB)
1962 return -EOPNOTSUPP;
1963
1964 other = unix_peer(sk);
1965 if (!other || sk->sk_state != TCP_ESTABLISHED)
1966 return -ENOTCONN;
1967
1968 if (false) {
1969alloc_skb:
1970 unix_state_unlock(other);
1971 mutex_unlock(&unix_sk(other)->readlock);
1972 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
1973 &err, 0);
1974 if (!newskb)
1975 goto err;
1976 }
1977
1978 /* we must acquire readlock as we modify already present
1979 * skbs in the sk_receive_queue and mess with skb->len
1980 */
1981 err = mutex_lock_interruptible(&unix_sk(other)->readlock);
1982 if (err) {
1983 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
1984 goto err;
1985 }
1986
1987 if (sk->sk_shutdown & SEND_SHUTDOWN) {
1988 err = -EPIPE;
1989 send_sigpipe = true;
1990 goto err_unlock;
1991 }
1992
1993 unix_state_lock(other);
1994
1995 if (sock_flag(other, SOCK_DEAD) ||
1996 other->sk_shutdown & RCV_SHUTDOWN) {
1997 err = -EPIPE;
1998 send_sigpipe = true;
1999 goto err_state_unlock;
2000 }
2001
2002 if (init_scm) {
2003 err = maybe_init_creds(&scm, socket, other);
2004 if (err)
2005 goto err_state_unlock;
2006 init_scm = false;
2007 }
2008
2009 skb = skb_peek_tail(&other->sk_receive_queue);
2010 if (tail && tail == skb) {
2011 skb = newskb;
2012 } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
2013 if (newskb) {
2014 skb = newskb;
2015 } else {
2016 tail = skb;
2017 goto alloc_skb;
2018 }
2019 } else if (newskb) {
2020 /* this is fast path, we don't necessarily need to
2021 * call to kfree_skb even though with newskb == NULL
2022 * this - does no harm
2023 */
2024 consume_skb(newskb);
2025 newskb = NULL;
2026 }
2027
2028 if (skb_append_pagefrags(skb, page, offset, size)) {
2029 tail = skb;
2030 goto alloc_skb;
2031 }
2032
2033 skb->len += size;
2034 skb->data_len += size;
2035 skb->truesize += size;
2036 atomic_add(size, &sk->sk_wmem_alloc);
2037
2038 if (newskb) {
2039 err = unix_scm_to_skb(&scm, skb, false);
2040 if (err)
2041 goto err_state_unlock;
2042 spin_lock(&other->sk_receive_queue.lock);
2043 __skb_queue_tail(&other->sk_receive_queue, newskb);
2044 spin_unlock(&other->sk_receive_queue.lock);
2045 }
2046
2047 unix_state_unlock(other);
2048 mutex_unlock(&unix_sk(other)->readlock);
2049
2050 other->sk_data_ready(other);
2051 scm_destroy(&scm);
2052 return size;
2053
2054err_state_unlock:
2055 unix_state_unlock(other);
2056err_unlock:
2057 mutex_unlock(&unix_sk(other)->readlock);
2058err:
2059 kfree_skb(newskb);
2060 if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2061 send_sig(SIGPIPE, current, 0);
2062 if (!init_scm)
2063 scm_destroy(&scm);
2064 return err;
2065}
2066
2067static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2068 size_t len)
2069{
2070 int err;
2071 struct sock *sk = sock->sk;
2072
2073 err = sock_error(sk);
2074 if (err)
2075 return err;
2076
2077 if (sk->sk_state != TCP_ESTABLISHED)
2078 return -ENOTCONN;
2079
2080 if (msg->msg_namelen)
2081 msg->msg_namelen = 0;
2082
2083 return unix_dgram_sendmsg(sock, msg, len);
2084}
2085
2086static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2087 size_t size, int flags)
2088{
2089 struct sock *sk = sock->sk;
2090
2091 if (sk->sk_state != TCP_ESTABLISHED)
2092 return -ENOTCONN;
2093
2094 return unix_dgram_recvmsg(sock, msg, size, flags);
2095}
2096
2097static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2098{
2099 struct unix_sock *u = unix_sk(sk);
2100
2101 if (u->addr) {
2102 msg->msg_namelen = u->addr->len;
2103 memcpy(msg->msg_name, u->addr->name, u->addr->len);
2104 }
2105}
2106
2107static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
2108 size_t size, int flags)
2109{
2110 struct scm_cookie scm;
2111 struct sock *sk = sock->sk;
2112 struct unix_sock *u = unix_sk(sk);
2113 struct sk_buff *skb, *last;
2114 long timeo;
2115 int err;
2116 int peeked, skip;
2117
2118 err = -EOPNOTSUPP;
2119 if (flags&MSG_OOB)
2120 goto out;
2121
2122 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2123
2124 do {
2125 mutex_lock(&u->readlock);
2126
2127 skip = sk_peek_offset(sk, flags);
2128 skb = __skb_try_recv_datagram(sk, flags, &peeked, &skip, &err,
2129 &last);
2130 if (skb)
2131 break;
2132
2133 mutex_unlock(&u->readlock);
2134
2135 if (err != -EAGAIN)
2136 break;
2137 } while (timeo &&
2138 !__skb_wait_for_more_packets(sk, &err, &timeo, last));
2139
2140 if (!skb) { /* implies readlock unlocked */
2141 unix_state_lock(sk);
2142 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2143 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2144 (sk->sk_shutdown & RCV_SHUTDOWN))
2145 err = 0;
2146 unix_state_unlock(sk);
2147 goto out;
2148 }
2149
2150 if (wq_has_sleeper(&u->peer_wait))
2151 wake_up_interruptible_sync_poll(&u->peer_wait,
2152 POLLOUT | POLLWRNORM |
2153 POLLWRBAND);
2154
2155 if (msg->msg_name)
2156 unix_copy_addr(msg, skb->sk);
2157
2158 if (size > skb->len - skip)
2159 size = skb->len - skip;
2160 else if (size < skb->len - skip)
2161 msg->msg_flags |= MSG_TRUNC;
2162
2163 err = skb_copy_datagram_msg(skb, skip, msg, size);
2164 if (err)
2165 goto out_free;
2166
2167 if (sock_flag(sk, SOCK_RCVTSTAMP))
2168 __sock_recv_timestamp(msg, sk, skb);
2169
2170 memset(&scm, 0, sizeof(scm));
2171
2172 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2173 unix_set_secdata(&scm, skb);
2174
2175 if (!(flags & MSG_PEEK)) {
2176 if (UNIXCB(skb).fp)
2177 unix_detach_fds(&scm, skb);
2178
2179 sk_peek_offset_bwd(sk, skb->len);
2180 } else {
2181 /* It is questionable: on PEEK we could:
2182 - do not return fds - good, but too simple 8)
2183 - return fds, and do not return them on read (old strategy,
2184 apparently wrong)
2185 - clone fds (I chose it for now, it is the most universal
2186 solution)
2187
2188 POSIX 1003.1g does not actually define this clearly
2189 at all. POSIX 1003.1g doesn't define a lot of things
2190 clearly however!
2191
2192 */
2193
2194 sk_peek_offset_fwd(sk, size);
2195
2196 if (UNIXCB(skb).fp)
2197 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2198 }
2199 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2200
2201 scm_recv(sock, msg, &scm, flags);
2202
2203out_free:
2204 skb_free_datagram(sk, skb);
2205 mutex_unlock(&u->readlock);
2206out:
2207 return err;
2208}
2209
2210/*
2211 * Sleep until more data has arrived. But check for races..
2212 */
2213static long unix_stream_data_wait(struct sock *sk, long timeo,
2214 struct sk_buff *last, unsigned int last_len)
2215{
2216 struct sk_buff *tail;
2217 DEFINE_WAIT(wait);
2218
2219 unix_state_lock(sk);
2220
2221 for (;;) {
2222 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2223
2224 tail = skb_peek_tail(&sk->sk_receive_queue);
2225 if (tail != last ||
2226 (tail && tail->len != last_len) ||
2227 sk->sk_err ||
2228 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2229 signal_pending(current) ||
2230 !timeo)
2231 break;
2232
2233 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2234 unix_state_unlock(sk);
2235 timeo = freezable_schedule_timeout(timeo);
2236 unix_state_lock(sk);
2237
2238 if (sock_flag(sk, SOCK_DEAD))
2239 break;
2240
2241 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2242 }
2243
2244 finish_wait(sk_sleep(sk), &wait);
2245 unix_state_unlock(sk);
2246 return timeo;
2247}
2248
2249static unsigned int unix_skb_len(const struct sk_buff *skb)
2250{
2251 return skb->len - UNIXCB(skb).consumed;
2252}
2253
2254struct unix_stream_read_state {
2255 int (*recv_actor)(struct sk_buff *, int, int,
2256 struct unix_stream_read_state *);
2257 struct socket *socket;
2258 struct msghdr *msg;
2259 struct pipe_inode_info *pipe;
2260 size_t size;
2261 int flags;
2262 unsigned int splice_flags;
2263};
2264
2265static int unix_stream_read_generic(struct unix_stream_read_state *state)
2266{
2267 struct scm_cookie scm;
2268 struct socket *sock = state->socket;
2269 struct sock *sk = sock->sk;
2270 struct unix_sock *u = unix_sk(sk);
2271 int copied = 0;
2272 int flags = state->flags;
2273 int noblock = flags & MSG_DONTWAIT;
2274 bool check_creds = false;
2275 int target;
2276 int err = 0;
2277 long timeo;
2278 int skip;
2279 size_t size = state->size;
2280 unsigned int last_len;
2281
2282 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2283 err = -EINVAL;
2284 goto out;
2285 }
2286
2287 if (unlikely(flags & MSG_OOB)) {
2288 err = -EOPNOTSUPP;
2289 goto out;
2290 }
2291
2292 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2293 timeo = sock_rcvtimeo(sk, noblock);
2294
2295 memset(&scm, 0, sizeof(scm));
2296
2297 /* Lock the socket to prevent queue disordering
2298 * while sleeps in memcpy_tomsg
2299 */
2300 mutex_lock(&u->readlock);
2301
2302 if (flags & MSG_PEEK)
2303 skip = sk_peek_offset(sk, flags);
2304 else
2305 skip = 0;
2306
2307 do {
2308 int chunk;
2309 bool drop_skb;
2310 struct sk_buff *skb, *last;
2311
2312redo:
2313 unix_state_lock(sk);
2314 if (sock_flag(sk, SOCK_DEAD)) {
2315 err = -ECONNRESET;
2316 goto unlock;
2317 }
2318 last = skb = skb_peek(&sk->sk_receive_queue);
2319 last_len = last ? last->len : 0;
2320again:
2321 if (skb == NULL) {
2322 unix_sk(sk)->recursion_level = 0;
2323 if (copied >= target)
2324 goto unlock;
2325
2326 /*
2327 * POSIX 1003.1g mandates this order.
2328 */
2329
2330 err = sock_error(sk);
2331 if (err)
2332 goto unlock;
2333 if (sk->sk_shutdown & RCV_SHUTDOWN)
2334 goto unlock;
2335
2336 unix_state_unlock(sk);
2337 if (!timeo) {
2338 err = -EAGAIN;
2339 break;
2340 }
2341
2342 mutex_unlock(&u->readlock);
2343
2344 timeo = unix_stream_data_wait(sk, timeo, last,
2345 last_len);
2346
2347 if (signal_pending(current)) {
2348 err = sock_intr_errno(timeo);
2349 scm_destroy(&scm);
2350 goto out;
2351 }
2352
2353 mutex_lock(&u->readlock);
2354 goto redo;
2355unlock:
2356 unix_state_unlock(sk);
2357 break;
2358 }
2359
2360 while (skip >= unix_skb_len(skb)) {
2361 skip -= unix_skb_len(skb);
2362 last = skb;
2363 last_len = skb->len;
2364 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2365 if (!skb)
2366 goto again;
2367 }
2368
2369 unix_state_unlock(sk);
2370
2371 if (check_creds) {
2372 /* Never glue messages from different writers */
2373 if (!unix_skb_scm_eq(skb, &scm))
2374 break;
2375 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2376 /* Copy credentials */
2377 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2378 unix_set_secdata(&scm, skb);
2379 check_creds = true;
2380 }
2381
2382 /* Copy address just once */
2383 if (state->msg && state->msg->msg_name) {
2384 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2385 state->msg->msg_name);
2386 unix_copy_addr(state->msg, skb->sk);
2387 sunaddr = NULL;
2388 }
2389
2390 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2391 skb_get(skb);
2392 chunk = state->recv_actor(skb, skip, chunk, state);
2393 drop_skb = !unix_skb_len(skb);
2394 /* skb is only safe to use if !drop_skb */
2395 consume_skb(skb);
2396 if (chunk < 0) {
2397 if (copied == 0)
2398 copied = -EFAULT;
2399 break;
2400 }
2401 copied += chunk;
2402 size -= chunk;
2403
2404 if (drop_skb) {
2405 /* the skb was touched by a concurrent reader;
2406 * we should not expect anything from this skb
2407 * anymore and assume it invalid - we can be
2408 * sure it was dropped from the socket queue
2409 *
2410 * let's report a short read
2411 */
2412 err = 0;
2413 break;
2414 }
2415
2416 /* Mark read part of skb as used */
2417 if (!(flags & MSG_PEEK)) {
2418 UNIXCB(skb).consumed += chunk;
2419
2420 sk_peek_offset_bwd(sk, chunk);
2421
2422 if (UNIXCB(skb).fp)
2423 unix_detach_fds(&scm, skb);
2424
2425 if (unix_skb_len(skb))
2426 break;
2427
2428 skb_unlink(skb, &sk->sk_receive_queue);
2429 consume_skb(skb);
2430
2431 if (scm.fp)
2432 break;
2433 } else {
2434 /* It is questionable, see note in unix_dgram_recvmsg.
2435 */
2436 if (UNIXCB(skb).fp)
2437 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2438
2439 sk_peek_offset_fwd(sk, chunk);
2440
2441 if (UNIXCB(skb).fp)
2442 break;
2443
2444 skip = 0;
2445 last = skb;
2446 last_len = skb->len;
2447 unix_state_lock(sk);
2448 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2449 if (skb)
2450 goto again;
2451 unix_state_unlock(sk);
2452 break;
2453 }
2454 } while (size);
2455
2456 mutex_unlock(&u->readlock);
2457 if (state->msg)
2458 scm_recv(sock, state->msg, &scm, flags);
2459 else
2460 scm_destroy(&scm);
2461out:
2462 return copied ? : err;
2463}
2464
2465static int unix_stream_read_actor(struct sk_buff *skb,
2466 int skip, int chunk,
2467 struct unix_stream_read_state *state)
2468{
2469 int ret;
2470
2471 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2472 state->msg, chunk);
2473 return ret ?: chunk;
2474}
2475
2476static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2477 size_t size, int flags)
2478{
2479 struct unix_stream_read_state state = {
2480 .recv_actor = unix_stream_read_actor,
2481 .socket = sock,
2482 .msg = msg,
2483 .size = size,
2484 .flags = flags
2485 };
2486
2487 return unix_stream_read_generic(&state);
2488}
2489
2490static ssize_t skb_unix_socket_splice(struct sock *sk,
2491 struct pipe_inode_info *pipe,
2492 struct splice_pipe_desc *spd)
2493{
2494 int ret;
2495 struct unix_sock *u = unix_sk(sk);
2496
2497 mutex_unlock(&u->readlock);
2498 ret = splice_to_pipe(pipe, spd);
2499 mutex_lock(&u->readlock);
2500
2501 return ret;
2502}
2503
2504static int unix_stream_splice_actor(struct sk_buff *skb,
2505 int skip, int chunk,
2506 struct unix_stream_read_state *state)
2507{
2508 return skb_splice_bits(skb, state->socket->sk,
2509 UNIXCB(skb).consumed + skip,
2510 state->pipe, chunk, state->splice_flags,
2511 skb_unix_socket_splice);
2512}
2513
2514static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2515 struct pipe_inode_info *pipe,
2516 size_t size, unsigned int flags)
2517{
2518 struct unix_stream_read_state state = {
2519 .recv_actor = unix_stream_splice_actor,
2520 .socket = sock,
2521 .pipe = pipe,
2522 .size = size,
2523 .splice_flags = flags,
2524 };
2525
2526 if (unlikely(*ppos))
2527 return -ESPIPE;
2528
2529 if (sock->file->f_flags & O_NONBLOCK ||
2530 flags & SPLICE_F_NONBLOCK)
2531 state.flags = MSG_DONTWAIT;
2532
2533 return unix_stream_read_generic(&state);
2534}
2535
2536static int unix_shutdown(struct socket *sock, int mode)
2537{
2538 struct sock *sk = sock->sk;
2539 struct sock *other;
2540
2541 if (mode < SHUT_RD || mode > SHUT_RDWR)
2542 return -EINVAL;
2543 /* This maps:
2544 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2545 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2546 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2547 */
2548 ++mode;
2549
2550 unix_state_lock(sk);
2551 sk->sk_shutdown |= mode;
2552 other = unix_peer(sk);
2553 if (other)
2554 sock_hold(other);
2555 unix_state_unlock(sk);
2556 sk->sk_state_change(sk);
2557
2558 if (other &&
2559 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2560
2561 int peer_mode = 0;
2562
2563 if (mode&RCV_SHUTDOWN)
2564 peer_mode |= SEND_SHUTDOWN;
2565 if (mode&SEND_SHUTDOWN)
2566 peer_mode |= RCV_SHUTDOWN;
2567 unix_state_lock(other);
2568 other->sk_shutdown |= peer_mode;
2569 unix_state_unlock(other);
2570 other->sk_state_change(other);
2571 if (peer_mode == SHUTDOWN_MASK)
2572 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2573 else if (peer_mode & RCV_SHUTDOWN)
2574 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2575 }
2576 if (other)
2577 sock_put(other);
2578
2579 return 0;
2580}
2581
2582long unix_inq_len(struct sock *sk)
2583{
2584 struct sk_buff *skb;
2585 long amount = 0;
2586
2587 if (sk->sk_state == TCP_LISTEN)
2588 return -EINVAL;
2589
2590 spin_lock(&sk->sk_receive_queue.lock);
2591 if (sk->sk_type == SOCK_STREAM ||
2592 sk->sk_type == SOCK_SEQPACKET) {
2593 skb_queue_walk(&sk->sk_receive_queue, skb)
2594 amount += unix_skb_len(skb);
2595 } else {
2596 skb = skb_peek(&sk->sk_receive_queue);
2597 if (skb)
2598 amount = skb->len;
2599 }
2600 spin_unlock(&sk->sk_receive_queue.lock);
2601
2602 return amount;
2603}
2604EXPORT_SYMBOL_GPL(unix_inq_len);
2605
2606long unix_outq_len(struct sock *sk)
2607{
2608 return sk_wmem_alloc_get(sk);
2609}
2610EXPORT_SYMBOL_GPL(unix_outq_len);
2611
2612static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2613{
2614 struct sock *sk = sock->sk;
2615 long amount = 0;
2616 int err;
2617
2618 switch (cmd) {
2619 case SIOCOUTQ:
2620 amount = unix_outq_len(sk);
2621 err = put_user(amount, (int __user *)arg);
2622 break;
2623 case SIOCINQ:
2624 amount = unix_inq_len(sk);
2625 if (amount < 0)
2626 err = amount;
2627 else
2628 err = put_user(amount, (int __user *)arg);
2629 break;
2630 default:
2631 err = -ENOIOCTLCMD;
2632 break;
2633 }
2634 return err;
2635}
2636
2637static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2638{
2639 struct sock *sk = sock->sk;
2640 unsigned int mask;
2641
2642 sock_poll_wait(file, sk_sleep(sk), wait);
2643 mask = 0;
2644
2645 /* exceptional events? */
2646 if (sk->sk_err)
2647 mask |= POLLERR;
2648 if (sk->sk_shutdown == SHUTDOWN_MASK)
2649 mask |= POLLHUP;
2650 if (sk->sk_shutdown & RCV_SHUTDOWN)
2651 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2652
2653 /* readable? */
2654 if (!skb_queue_empty(&sk->sk_receive_queue))
2655 mask |= POLLIN | POLLRDNORM;
2656
2657 /* Connection-based need to check for termination and startup */
2658 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2659 sk->sk_state == TCP_CLOSE)
2660 mask |= POLLHUP;
2661
2662 /*
2663 * we set writable also when the other side has shut down the
2664 * connection. This prevents stuck sockets.
2665 */
2666 if (unix_writable(sk))
2667 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2668
2669 return mask;
2670}
2671
2672static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2673 poll_table *wait)
2674{
2675 struct sock *sk = sock->sk, *other;
2676 unsigned int mask, writable;
2677
2678 sock_poll_wait(file, sk_sleep(sk), wait);
2679 mask = 0;
2680
2681 /* exceptional events? */
2682 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2683 mask |= POLLERR |
2684 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2685
2686 if (sk->sk_shutdown & RCV_SHUTDOWN)
2687 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2688 if (sk->sk_shutdown == SHUTDOWN_MASK)
2689 mask |= POLLHUP;
2690
2691 /* readable? */
2692 if (!skb_queue_empty(&sk->sk_receive_queue))
2693 mask |= POLLIN | POLLRDNORM;
2694
2695 /* Connection-based need to check for termination and startup */
2696 if (sk->sk_type == SOCK_SEQPACKET) {
2697 if (sk->sk_state == TCP_CLOSE)
2698 mask |= POLLHUP;
2699 /* connection hasn't started yet? */
2700 if (sk->sk_state == TCP_SYN_SENT)
2701 return mask;
2702 }
2703
2704 /* No write status requested, avoid expensive OUT tests. */
2705 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
2706 return mask;
2707
2708 writable = unix_writable(sk);
2709 if (writable) {
2710 unix_state_lock(sk);
2711
2712 other = unix_peer(sk);
2713 if (other && unix_peer(other) != sk &&
2714 unix_recvq_full(other) &&
2715 unix_dgram_peer_wake_me(sk, other))
2716 writable = 0;
2717
2718 unix_state_unlock(sk);
2719 }
2720
2721 if (writable)
2722 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2723 else
2724 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2725
2726 return mask;
2727}
2728
2729#ifdef CONFIG_PROC_FS
2730
2731#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2732
2733#define get_bucket(x) ((x) >> BUCKET_SPACE)
2734#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2735#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2736
2737static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2738{
2739 unsigned long offset = get_offset(*pos);
2740 unsigned long bucket = get_bucket(*pos);
2741 struct sock *sk;
2742 unsigned long count = 0;
2743
2744 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2745 if (sock_net(sk) != seq_file_net(seq))
2746 continue;
2747 if (++count == offset)
2748 break;
2749 }
2750
2751 return sk;
2752}
2753
2754static struct sock *unix_next_socket(struct seq_file *seq,
2755 struct sock *sk,
2756 loff_t *pos)
2757{
2758 unsigned long bucket;
2759
2760 while (sk > (struct sock *)SEQ_START_TOKEN) {
2761 sk = sk_next(sk);
2762 if (!sk)
2763 goto next_bucket;
2764 if (sock_net(sk) == seq_file_net(seq))
2765 return sk;
2766 }
2767
2768 do {
2769 sk = unix_from_bucket(seq, pos);
2770 if (sk)
2771 return sk;
2772
2773next_bucket:
2774 bucket = get_bucket(*pos) + 1;
2775 *pos = set_bucket_offset(bucket, 1);
2776 } while (bucket < ARRAY_SIZE(unix_socket_table));
2777
2778 return NULL;
2779}
2780
2781static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2782 __acquires(unix_table_lock)
2783{
2784 spin_lock(&unix_table_lock);
2785
2786 if (!*pos)
2787 return SEQ_START_TOKEN;
2788
2789 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2790 return NULL;
2791
2792 return unix_next_socket(seq, NULL, pos);
2793}
2794
2795static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2796{
2797 ++*pos;
2798 return unix_next_socket(seq, v, pos);
2799}
2800
2801static void unix_seq_stop(struct seq_file *seq, void *v)
2802 __releases(unix_table_lock)
2803{
2804 spin_unlock(&unix_table_lock);
2805}
2806
2807static int unix_seq_show(struct seq_file *seq, void *v)
2808{
2809
2810 if (v == SEQ_START_TOKEN)
2811 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2812 "Inode Path\n");
2813 else {
2814 struct sock *s = v;
2815 struct unix_sock *u = unix_sk(s);
2816 unix_state_lock(s);
2817
2818 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2819 s,
2820 atomic_read(&s->sk_refcnt),
2821 0,
2822 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2823 s->sk_type,
2824 s->sk_socket ?
2825 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2826 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2827 sock_i_ino(s));
2828
2829 if (u->addr) {
2830 int i, len;
2831 seq_putc(seq, ' ');
2832
2833 i = 0;
2834 len = u->addr->len - sizeof(short);
2835 if (!UNIX_ABSTRACT(s))
2836 len--;
2837 else {
2838 seq_putc(seq, '@');
2839 i++;
2840 }
2841 for ( ; i < len; i++)
2842 seq_putc(seq, u->addr->name->sun_path[i]);
2843 }
2844 unix_state_unlock(s);
2845 seq_putc(seq, '\n');
2846 }
2847
2848 return 0;
2849}
2850
2851static const struct seq_operations unix_seq_ops = {
2852 .start = unix_seq_start,
2853 .next = unix_seq_next,
2854 .stop = unix_seq_stop,
2855 .show = unix_seq_show,
2856};
2857
2858static int unix_seq_open(struct inode *inode, struct file *file)
2859{
2860 return seq_open_net(inode, file, &unix_seq_ops,
2861 sizeof(struct seq_net_private));
2862}
2863
2864static const struct file_operations unix_seq_fops = {
2865 .owner = THIS_MODULE,
2866 .open = unix_seq_open,
2867 .read = seq_read,
2868 .llseek = seq_lseek,
2869 .release = seq_release_net,
2870};
2871
2872#endif
2873
2874static const struct net_proto_family unix_family_ops = {
2875 .family = PF_UNIX,
2876 .create = unix_create,
2877 .owner = THIS_MODULE,
2878};
2879
2880
2881static int __net_init unix_net_init(struct net *net)
2882{
2883 int error = -ENOMEM;
2884
2885 net->unx.sysctl_max_dgram_qlen = 10;
2886 if (unix_sysctl_register(net))
2887 goto out;
2888
2889#ifdef CONFIG_PROC_FS
2890 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2891 unix_sysctl_unregister(net);
2892 goto out;
2893 }
2894#endif
2895 error = 0;
2896out:
2897 return error;
2898}
2899
2900static void __net_exit unix_net_exit(struct net *net)
2901{
2902 unix_sysctl_unregister(net);
2903 remove_proc_entry("unix", net->proc_net);
2904}
2905
2906static struct pernet_operations unix_net_ops = {
2907 .init = unix_net_init,
2908 .exit = unix_net_exit,
2909};
2910
2911static int __init af_unix_init(void)
2912{
2913 int rc = -1;
2914
2915 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2916
2917 rc = proto_register(&unix_proto, 1);
2918 if (rc != 0) {
2919 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
2920 goto out;
2921 }
2922
2923 sock_register(&unix_family_ops);
2924 register_pernet_subsys(&unix_net_ops);
2925out:
2926 return rc;
2927}
2928
2929static void __exit af_unix_exit(void)
2930{
2931 sock_unregister(PF_UNIX);
2932 proto_unregister(&unix_proto);
2933 unregister_pernet_subsys(&unix_net_ops);
2934}
2935
2936/* Earlier than device_initcall() so that other drivers invoking
2937 request_module() don't end up in a loop when modprobe tries
2938 to use a UNIX socket. But later than subsys_initcall() because
2939 we depend on stuff initialised there */
2940fs_initcall(af_unix_init);
2941module_exit(af_unix_exit);
2942
2943MODULE_LICENSE("GPL");
2944MODULE_ALIAS_NETPROTO(PF_UNIX);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * NET4: Implementation of BSD Unix domain sockets.
4 *
5 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
6 *
7 * Fixes:
8 * Linus Torvalds : Assorted bug cures.
9 * Niibe Yutaka : async I/O support.
10 * Carsten Paeth : PF_UNIX check, address fixes.
11 * Alan Cox : Limit size of allocated blocks.
12 * Alan Cox : Fixed the stupid socketpair bug.
13 * Alan Cox : BSD compatibility fine tuning.
14 * Alan Cox : Fixed a bug in connect when interrupted.
15 * Alan Cox : Sorted out a proper draft version of
16 * file descriptor passing hacked up from
17 * Mike Shaver's work.
18 * Marty Leisner : Fixes to fd passing
19 * Nick Nevin : recvmsg bugfix.
20 * Alan Cox : Started proper garbage collector
21 * Heiko EiBfeldt : Missing verify_area check
22 * Alan Cox : Started POSIXisms
23 * Andreas Schwab : Replace inode by dentry for proper
24 * reference counting
25 * Kirk Petersen : Made this a module
26 * Christoph Rohland : Elegant non-blocking accept/connect algorithm.
27 * Lots of bug fixes.
28 * Alexey Kuznetosv : Repaired (I hope) bugs introduces
29 * by above two patches.
30 * Andrea Arcangeli : If possible we block in connect(2)
31 * if the max backlog of the listen socket
32 * is been reached. This won't break
33 * old apps and it will avoid huge amount
34 * of socks hashed (this for unix_gc()
35 * performances reasons).
36 * Security fix that limits the max
37 * number of socks to 2*max_files and
38 * the number of skb queueable in the
39 * dgram receiver.
40 * Artur Skawina : Hash function optimizations
41 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
42 * Malcolm Beattie : Set peercred for socketpair
43 * Michal Ostrowski : Module initialization cleanup.
44 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT,
45 * the core infrastructure is doing that
46 * for all net proto families now (2.5.69+)
47 *
48 * Known differences from reference BSD that was tested:
49 *
50 * [TO FIX]
51 * ECONNREFUSED is not returned from one end of a connected() socket to the
52 * other the moment one end closes.
53 * fstat() doesn't return st_dev=0, and give the blksize as high water mark
54 * and a fake inode identifier (nor the BSD first socket fstat twice bug).
55 * [NOT TO FIX]
56 * accept() returns a path name even if the connecting socket has closed
57 * in the meantime (BSD loses the path and gives up).
58 * accept() returns 0 length path for an unbound connector. BSD returns 16
59 * and a null first byte in the path (but not for gethost/peername - BSD bug ??)
60 * socketpair(...SOCK_RAW..) doesn't panic the kernel.
61 * BSD af_unix apparently has connect forgetting to block properly.
62 * (need to check this with the POSIX spec in detail)
63 *
64 * Differences from 2.0.0-11-... (ANK)
65 * Bug fixes and improvements.
66 * - client shutdown killed server socket.
67 * - removed all useless cli/sti pairs.
68 *
69 * Semantic changes/extensions.
70 * - generic control message passing.
71 * - SCM_CREDENTIALS control message.
72 * - "Abstract" (not FS based) socket bindings.
73 * Abstract names are sequences of bytes (not zero terminated)
74 * started by 0, so that this name space does not intersect
75 * with BSD names.
76 */
77
78#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
79
80#include <linux/module.h>
81#include <linux/kernel.h>
82#include <linux/signal.h>
83#include <linux/sched/signal.h>
84#include <linux/errno.h>
85#include <linux/string.h>
86#include <linux/stat.h>
87#include <linux/dcache.h>
88#include <linux/namei.h>
89#include <linux/socket.h>
90#include <linux/un.h>
91#include <linux/fcntl.h>
92#include <linux/termios.h>
93#include <linux/sockios.h>
94#include <linux/net.h>
95#include <linux/in.h>
96#include <linux/fs.h>
97#include <linux/slab.h>
98#include <linux/uaccess.h>
99#include <linux/skbuff.h>
100#include <linux/netdevice.h>
101#include <net/net_namespace.h>
102#include <net/sock.h>
103#include <net/tcp_states.h>
104#include <net/af_unix.h>
105#include <linux/proc_fs.h>
106#include <linux/seq_file.h>
107#include <net/scm.h>
108#include <linux/init.h>
109#include <linux/poll.h>
110#include <linux/rtnetlink.h>
111#include <linux/mount.h>
112#include <net/checksum.h>
113#include <linux/security.h>
114#include <linux/freezer.h>
115#include <linux/file.h>
116
117#include "scm.h"
118
119struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
120EXPORT_SYMBOL_GPL(unix_socket_table);
121DEFINE_SPINLOCK(unix_table_lock);
122EXPORT_SYMBOL_GPL(unix_table_lock);
123static atomic_long_t unix_nr_socks;
124
125
126static struct hlist_head *unix_sockets_unbound(void *addr)
127{
128 unsigned long hash = (unsigned long)addr;
129
130 hash ^= hash >> 16;
131 hash ^= hash >> 8;
132 hash %= UNIX_HASH_SIZE;
133 return &unix_socket_table[UNIX_HASH_SIZE + hash];
134}
135
136#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
137
138#ifdef CONFIG_SECURITY_NETWORK
139static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
140{
141 UNIXCB(skb).secid = scm->secid;
142}
143
144static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
145{
146 scm->secid = UNIXCB(skb).secid;
147}
148
149static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
150{
151 return (scm->secid == UNIXCB(skb).secid);
152}
153#else
154static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
155{ }
156
157static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
158{ }
159
160static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
161{
162 return true;
163}
164#endif /* CONFIG_SECURITY_NETWORK */
165
166/*
167 * SMP locking strategy:
168 * hash table is protected with spinlock unix_table_lock
169 * each socket state is protected by separate spin lock.
170 */
171
172static inline unsigned int unix_hash_fold(__wsum n)
173{
174 unsigned int hash = (__force unsigned int)csum_fold(n);
175
176 hash ^= hash>>8;
177 return hash&(UNIX_HASH_SIZE-1);
178}
179
180#define unix_peer(sk) (unix_sk(sk)->peer)
181
182static inline int unix_our_peer(struct sock *sk, struct sock *osk)
183{
184 return unix_peer(osk) == sk;
185}
186
187static inline int unix_may_send(struct sock *sk, struct sock *osk)
188{
189 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
190}
191
192static inline int unix_recvq_full(const struct sock *sk)
193{
194 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
195}
196
197static inline int unix_recvq_full_lockless(const struct sock *sk)
198{
199 return skb_queue_len_lockless(&sk->sk_receive_queue) >
200 READ_ONCE(sk->sk_max_ack_backlog);
201}
202
203struct sock *unix_peer_get(struct sock *s)
204{
205 struct sock *peer;
206
207 unix_state_lock(s);
208 peer = unix_peer(s);
209 if (peer)
210 sock_hold(peer);
211 unix_state_unlock(s);
212 return peer;
213}
214EXPORT_SYMBOL_GPL(unix_peer_get);
215
216static inline void unix_release_addr(struct unix_address *addr)
217{
218 if (refcount_dec_and_test(&addr->refcnt))
219 kfree(addr);
220}
221
222/*
223 * Check unix socket name:
224 * - should be not zero length.
225 * - if started by not zero, should be NULL terminated (FS object)
226 * - if started by zero, it is abstract name.
227 */
228
229static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
230{
231 *hashp = 0;
232
233 if (len <= sizeof(short) || len > sizeof(*sunaddr))
234 return -EINVAL;
235 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
236 return -EINVAL;
237 if (sunaddr->sun_path[0]) {
238 /*
239 * This may look like an off by one error but it is a bit more
240 * subtle. 108 is the longest valid AF_UNIX path for a binding.
241 * sun_path[108] doesn't as such exist. However in kernel space
242 * we are guaranteed that it is a valid memory location in our
243 * kernel address buffer.
244 */
245 ((char *)sunaddr)[len] = 0;
246 len = strlen(sunaddr->sun_path)+1+sizeof(short);
247 return len;
248 }
249
250 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
251 return len;
252}
253
254static void __unix_remove_socket(struct sock *sk)
255{
256 sk_del_node_init(sk);
257}
258
259static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
260{
261 WARN_ON(!sk_unhashed(sk));
262 sk_add_node(sk, list);
263}
264
265static inline void unix_remove_socket(struct sock *sk)
266{
267 spin_lock(&unix_table_lock);
268 __unix_remove_socket(sk);
269 spin_unlock(&unix_table_lock);
270}
271
272static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
273{
274 spin_lock(&unix_table_lock);
275 __unix_insert_socket(list, sk);
276 spin_unlock(&unix_table_lock);
277}
278
279static struct sock *__unix_find_socket_byname(struct net *net,
280 struct sockaddr_un *sunname,
281 int len, int type, unsigned int hash)
282{
283 struct sock *s;
284
285 sk_for_each(s, &unix_socket_table[hash ^ type]) {
286 struct unix_sock *u = unix_sk(s);
287
288 if (!net_eq(sock_net(s), net))
289 continue;
290
291 if (u->addr->len == len &&
292 !memcmp(u->addr->name, sunname, len))
293 return s;
294 }
295 return NULL;
296}
297
298static inline struct sock *unix_find_socket_byname(struct net *net,
299 struct sockaddr_un *sunname,
300 int len, int type,
301 unsigned int hash)
302{
303 struct sock *s;
304
305 spin_lock(&unix_table_lock);
306 s = __unix_find_socket_byname(net, sunname, len, type, hash);
307 if (s)
308 sock_hold(s);
309 spin_unlock(&unix_table_lock);
310 return s;
311}
312
313static struct sock *unix_find_socket_byinode(struct inode *i)
314{
315 struct sock *s;
316
317 spin_lock(&unix_table_lock);
318 sk_for_each(s,
319 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
320 struct dentry *dentry = unix_sk(s)->path.dentry;
321
322 if (dentry && d_backing_inode(dentry) == i) {
323 sock_hold(s);
324 goto found;
325 }
326 }
327 s = NULL;
328found:
329 spin_unlock(&unix_table_lock);
330 return s;
331}
332
333/* Support code for asymmetrically connected dgram sockets
334 *
335 * If a datagram socket is connected to a socket not itself connected
336 * to the first socket (eg, /dev/log), clients may only enqueue more
337 * messages if the present receive queue of the server socket is not
338 * "too large". This means there's a second writeability condition
339 * poll and sendmsg need to test. The dgram recv code will do a wake
340 * up on the peer_wait wait queue of a socket upon reception of a
341 * datagram which needs to be propagated to sleeping would-be writers
342 * since these might not have sent anything so far. This can't be
343 * accomplished via poll_wait because the lifetime of the server
344 * socket might be less than that of its clients if these break their
345 * association with it or if the server socket is closed while clients
346 * are still connected to it and there's no way to inform "a polling
347 * implementation" that it should let go of a certain wait queue
348 *
349 * In order to propagate a wake up, a wait_queue_entry_t of the client
350 * socket is enqueued on the peer_wait queue of the server socket
351 * whose wake function does a wake_up on the ordinary client socket
352 * wait queue. This connection is established whenever a write (or
353 * poll for write) hit the flow control condition and broken when the
354 * association to the server socket is dissolved or after a wake up
355 * was relayed.
356 */
357
358static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
359 void *key)
360{
361 struct unix_sock *u;
362 wait_queue_head_t *u_sleep;
363
364 u = container_of(q, struct unix_sock, peer_wake);
365
366 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
367 q);
368 u->peer_wake.private = NULL;
369
370 /* relaying can only happen while the wq still exists */
371 u_sleep = sk_sleep(&u->sk);
372 if (u_sleep)
373 wake_up_interruptible_poll(u_sleep, key_to_poll(key));
374
375 return 0;
376}
377
378static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
379{
380 struct unix_sock *u, *u_other;
381 int rc;
382
383 u = unix_sk(sk);
384 u_other = unix_sk(other);
385 rc = 0;
386 spin_lock(&u_other->peer_wait.lock);
387
388 if (!u->peer_wake.private) {
389 u->peer_wake.private = other;
390 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
391
392 rc = 1;
393 }
394
395 spin_unlock(&u_other->peer_wait.lock);
396 return rc;
397}
398
399static void unix_dgram_peer_wake_disconnect(struct sock *sk,
400 struct sock *other)
401{
402 struct unix_sock *u, *u_other;
403
404 u = unix_sk(sk);
405 u_other = unix_sk(other);
406 spin_lock(&u_other->peer_wait.lock);
407
408 if (u->peer_wake.private == other) {
409 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
410 u->peer_wake.private = NULL;
411 }
412
413 spin_unlock(&u_other->peer_wait.lock);
414}
415
416static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
417 struct sock *other)
418{
419 unix_dgram_peer_wake_disconnect(sk, other);
420 wake_up_interruptible_poll(sk_sleep(sk),
421 EPOLLOUT |
422 EPOLLWRNORM |
423 EPOLLWRBAND);
424}
425
426/* preconditions:
427 * - unix_peer(sk) == other
428 * - association is stable
429 */
430static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
431{
432 int connected;
433
434 connected = unix_dgram_peer_wake_connect(sk, other);
435
436 /* If other is SOCK_DEAD, we want to make sure we signal
437 * POLLOUT, such that a subsequent write() can get a
438 * -ECONNREFUSED. Otherwise, if we haven't queued any skbs
439 * to other and its full, we will hang waiting for POLLOUT.
440 */
441 if (unix_recvq_full(other) && !sock_flag(other, SOCK_DEAD))
442 return 1;
443
444 if (connected)
445 unix_dgram_peer_wake_disconnect(sk, other);
446
447 return 0;
448}
449
450static int unix_writable(const struct sock *sk)
451{
452 return sk->sk_state != TCP_LISTEN &&
453 (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
454}
455
456static void unix_write_space(struct sock *sk)
457{
458 struct socket_wq *wq;
459
460 rcu_read_lock();
461 if (unix_writable(sk)) {
462 wq = rcu_dereference(sk->sk_wq);
463 if (skwq_has_sleeper(wq))
464 wake_up_interruptible_sync_poll(&wq->wait,
465 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
466 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
467 }
468 rcu_read_unlock();
469}
470
471/* When dgram socket disconnects (or changes its peer), we clear its receive
472 * queue of packets arrived from previous peer. First, it allows to do
473 * flow control based only on wmem_alloc; second, sk connected to peer
474 * may receive messages only from that peer. */
475static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
476{
477 if (!skb_queue_empty(&sk->sk_receive_queue)) {
478 skb_queue_purge(&sk->sk_receive_queue);
479 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
480
481 /* If one link of bidirectional dgram pipe is disconnected,
482 * we signal error. Messages are lost. Do not make this,
483 * when peer was not connected to us.
484 */
485 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
486 other->sk_err = ECONNRESET;
487 other->sk_error_report(other);
488 }
489 }
490}
491
492static void unix_sock_destructor(struct sock *sk)
493{
494 struct unix_sock *u = unix_sk(sk);
495
496 skb_queue_purge(&sk->sk_receive_queue);
497
498 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
499 WARN_ON(!sk_unhashed(sk));
500 WARN_ON(sk->sk_socket);
501 if (!sock_flag(sk, SOCK_DEAD)) {
502 pr_info("Attempt to release alive unix socket: %p\n", sk);
503 return;
504 }
505
506 if (u->addr)
507 unix_release_addr(u->addr);
508
509 atomic_long_dec(&unix_nr_socks);
510 local_bh_disable();
511 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
512 local_bh_enable();
513#ifdef UNIX_REFCNT_DEBUG
514 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
515 atomic_long_read(&unix_nr_socks));
516#endif
517}
518
519static void unix_release_sock(struct sock *sk, int embrion)
520{
521 struct unix_sock *u = unix_sk(sk);
522 struct path path;
523 struct sock *skpair;
524 struct sk_buff *skb;
525 int state;
526
527 unix_remove_socket(sk);
528
529 /* Clear state */
530 unix_state_lock(sk);
531 sock_orphan(sk);
532 sk->sk_shutdown = SHUTDOWN_MASK;
533 path = u->path;
534 u->path.dentry = NULL;
535 u->path.mnt = NULL;
536 state = sk->sk_state;
537 sk->sk_state = TCP_CLOSE;
538 unix_state_unlock(sk);
539
540 wake_up_interruptible_all(&u->peer_wait);
541
542 skpair = unix_peer(sk);
543
544 if (skpair != NULL) {
545 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
546 unix_state_lock(skpair);
547 /* No more writes */
548 skpair->sk_shutdown = SHUTDOWN_MASK;
549 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
550 skpair->sk_err = ECONNRESET;
551 unix_state_unlock(skpair);
552 skpair->sk_state_change(skpair);
553 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
554 }
555
556 unix_dgram_peer_wake_disconnect(sk, skpair);
557 sock_put(skpair); /* It may now die */
558 unix_peer(sk) = NULL;
559 }
560
561 /* Try to flush out this socket. Throw out buffers at least */
562
563 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
564 if (state == TCP_LISTEN)
565 unix_release_sock(skb->sk, 1);
566 /* passed fds are erased in the kfree_skb hook */
567 UNIXCB(skb).consumed = skb->len;
568 kfree_skb(skb);
569 }
570
571 if (path.dentry)
572 path_put(&path);
573
574 sock_put(sk);
575
576 /* ---- Socket is dead now and most probably destroyed ---- */
577
578 /*
579 * Fixme: BSD difference: In BSD all sockets connected to us get
580 * ECONNRESET and we die on the spot. In Linux we behave
581 * like files and pipes do and wait for the last
582 * dereference.
583 *
584 * Can't we simply set sock->err?
585 *
586 * What the above comment does talk about? --ANK(980817)
587 */
588
589 if (unix_tot_inflight)
590 unix_gc(); /* Garbage collect fds */
591}
592
593static void init_peercred(struct sock *sk)
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(task_tgid(current));
599 sk->sk_peer_cred = get_current_cred();
600}
601
602static void copy_peercred(struct sock *sk, struct sock *peersk)
603{
604 put_pid(sk->sk_peer_pid);
605 if (sk->sk_peer_cred)
606 put_cred(sk->sk_peer_cred);
607 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
608 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
609}
610
611static int unix_listen(struct socket *sock, int backlog)
612{
613 int err;
614 struct sock *sk = sock->sk;
615 struct unix_sock *u = unix_sk(sk);
616 struct pid *old_pid = NULL;
617
618 err = -EOPNOTSUPP;
619 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
620 goto out; /* Only stream/seqpacket sockets accept */
621 err = -EINVAL;
622 if (!u->addr)
623 goto out; /* No listens on an unbound socket */
624 unix_state_lock(sk);
625 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
626 goto out_unlock;
627 if (backlog > sk->sk_max_ack_backlog)
628 wake_up_interruptible_all(&u->peer_wait);
629 sk->sk_max_ack_backlog = backlog;
630 sk->sk_state = TCP_LISTEN;
631 /* set credentials so connect can copy them */
632 init_peercred(sk);
633 err = 0;
634
635out_unlock:
636 unix_state_unlock(sk);
637 put_pid(old_pid);
638out:
639 return err;
640}
641
642static int unix_release(struct socket *);
643static int unix_bind(struct socket *, struct sockaddr *, int);
644static int unix_stream_connect(struct socket *, struct sockaddr *,
645 int addr_len, int flags);
646static int unix_socketpair(struct socket *, struct socket *);
647static int unix_accept(struct socket *, struct socket *, int, bool);
648static int unix_getname(struct socket *, struct sockaddr *, int);
649static __poll_t unix_poll(struct file *, struct socket *, poll_table *);
650static __poll_t unix_dgram_poll(struct file *, struct socket *,
651 poll_table *);
652static int unix_ioctl(struct socket *, unsigned int, unsigned long);
653#ifdef CONFIG_COMPAT
654static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
655#endif
656static int unix_shutdown(struct socket *, int);
657static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
658static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
659static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
660 size_t size, int flags);
661static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
662 struct pipe_inode_info *, size_t size,
663 unsigned int flags);
664static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
665static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
666static int unix_dgram_connect(struct socket *, struct sockaddr *,
667 int, int);
668static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
669static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
670 int);
671
672static int unix_set_peek_off(struct sock *sk, int val)
673{
674 struct unix_sock *u = unix_sk(sk);
675
676 if (mutex_lock_interruptible(&u->iolock))
677 return -EINTR;
678
679 sk->sk_peek_off = val;
680 mutex_unlock(&u->iolock);
681
682 return 0;
683}
684
685#ifdef CONFIG_PROC_FS
686static void unix_show_fdinfo(struct seq_file *m, struct socket *sock)
687{
688 struct sock *sk = sock->sk;
689 struct unix_sock *u;
690
691 if (sk) {
692 u = unix_sk(sock->sk);
693 seq_printf(m, "scm_fds: %u\n",
694 atomic_read(&u->scm_stat.nr_fds));
695 }
696}
697#else
698#define unix_show_fdinfo NULL
699#endif
700
701static const struct proto_ops unix_stream_ops = {
702 .family = PF_UNIX,
703 .owner = THIS_MODULE,
704 .release = unix_release,
705 .bind = unix_bind,
706 .connect = unix_stream_connect,
707 .socketpair = unix_socketpair,
708 .accept = unix_accept,
709 .getname = unix_getname,
710 .poll = unix_poll,
711 .ioctl = unix_ioctl,
712#ifdef CONFIG_COMPAT
713 .compat_ioctl = unix_compat_ioctl,
714#endif
715 .listen = unix_listen,
716 .shutdown = unix_shutdown,
717 .sendmsg = unix_stream_sendmsg,
718 .recvmsg = unix_stream_recvmsg,
719 .mmap = sock_no_mmap,
720 .sendpage = unix_stream_sendpage,
721 .splice_read = unix_stream_splice_read,
722 .set_peek_off = unix_set_peek_off,
723 .show_fdinfo = unix_show_fdinfo,
724};
725
726static const struct proto_ops unix_dgram_ops = {
727 .family = PF_UNIX,
728 .owner = THIS_MODULE,
729 .release = unix_release,
730 .bind = unix_bind,
731 .connect = unix_dgram_connect,
732 .socketpair = unix_socketpair,
733 .accept = sock_no_accept,
734 .getname = unix_getname,
735 .poll = unix_dgram_poll,
736 .ioctl = unix_ioctl,
737#ifdef CONFIG_COMPAT
738 .compat_ioctl = unix_compat_ioctl,
739#endif
740 .listen = sock_no_listen,
741 .shutdown = unix_shutdown,
742 .sendmsg = unix_dgram_sendmsg,
743 .recvmsg = unix_dgram_recvmsg,
744 .mmap = sock_no_mmap,
745 .sendpage = sock_no_sendpage,
746 .set_peek_off = unix_set_peek_off,
747 .show_fdinfo = unix_show_fdinfo,
748};
749
750static const struct proto_ops unix_seqpacket_ops = {
751 .family = PF_UNIX,
752 .owner = THIS_MODULE,
753 .release = unix_release,
754 .bind = unix_bind,
755 .connect = unix_stream_connect,
756 .socketpair = unix_socketpair,
757 .accept = unix_accept,
758 .getname = unix_getname,
759 .poll = unix_dgram_poll,
760 .ioctl = unix_ioctl,
761#ifdef CONFIG_COMPAT
762 .compat_ioctl = unix_compat_ioctl,
763#endif
764 .listen = unix_listen,
765 .shutdown = unix_shutdown,
766 .sendmsg = unix_seqpacket_sendmsg,
767 .recvmsg = unix_seqpacket_recvmsg,
768 .mmap = sock_no_mmap,
769 .sendpage = sock_no_sendpage,
770 .set_peek_off = unix_set_peek_off,
771 .show_fdinfo = unix_show_fdinfo,
772};
773
774static struct proto unix_proto = {
775 .name = "UNIX",
776 .owner = THIS_MODULE,
777 .obj_size = sizeof(struct unix_sock),
778};
779
780static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
781{
782 struct sock *sk = NULL;
783 struct unix_sock *u;
784
785 atomic_long_inc(&unix_nr_socks);
786 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
787 goto out;
788
789 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
790 if (!sk)
791 goto out;
792
793 sock_init_data(sock, sk);
794
795 sk->sk_allocation = GFP_KERNEL_ACCOUNT;
796 sk->sk_write_space = unix_write_space;
797 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
798 sk->sk_destruct = unix_sock_destructor;
799 u = unix_sk(sk);
800 u->path.dentry = NULL;
801 u->path.mnt = NULL;
802 spin_lock_init(&u->lock);
803 atomic_long_set(&u->inflight, 0);
804 INIT_LIST_HEAD(&u->link);
805 mutex_init(&u->iolock); /* single task reading lock */
806 mutex_init(&u->bindlock); /* single task binding lock */
807 init_waitqueue_head(&u->peer_wait);
808 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
809 memset(&u->scm_stat, 0, sizeof(struct scm_stat));
810 unix_insert_socket(unix_sockets_unbound(sk), sk);
811out:
812 if (sk == NULL)
813 atomic_long_dec(&unix_nr_socks);
814 else {
815 local_bh_disable();
816 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
817 local_bh_enable();
818 }
819 return sk;
820}
821
822static int unix_create(struct net *net, struct socket *sock, int protocol,
823 int kern)
824{
825 if (protocol && protocol != PF_UNIX)
826 return -EPROTONOSUPPORT;
827
828 sock->state = SS_UNCONNECTED;
829
830 switch (sock->type) {
831 case SOCK_STREAM:
832 sock->ops = &unix_stream_ops;
833 break;
834 /*
835 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
836 * nothing uses it.
837 */
838 case SOCK_RAW:
839 sock->type = SOCK_DGRAM;
840 fallthrough;
841 case SOCK_DGRAM:
842 sock->ops = &unix_dgram_ops;
843 break;
844 case SOCK_SEQPACKET:
845 sock->ops = &unix_seqpacket_ops;
846 break;
847 default:
848 return -ESOCKTNOSUPPORT;
849 }
850
851 return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
852}
853
854static int unix_release(struct socket *sock)
855{
856 struct sock *sk = sock->sk;
857
858 if (!sk)
859 return 0;
860
861 unix_release_sock(sk, 0);
862 sock->sk = NULL;
863
864 return 0;
865}
866
867static int unix_autobind(struct socket *sock)
868{
869 struct sock *sk = sock->sk;
870 struct net *net = sock_net(sk);
871 struct unix_sock *u = unix_sk(sk);
872 static u32 ordernum = 1;
873 struct unix_address *addr;
874 int err;
875 unsigned int retries = 0;
876
877 err = mutex_lock_interruptible(&u->bindlock);
878 if (err)
879 return err;
880
881 err = 0;
882 if (u->addr)
883 goto out;
884
885 err = -ENOMEM;
886 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
887 if (!addr)
888 goto out;
889
890 addr->name->sun_family = AF_UNIX;
891 refcount_set(&addr->refcnt, 1);
892
893retry:
894 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
895 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
896
897 spin_lock(&unix_table_lock);
898 ordernum = (ordernum+1)&0xFFFFF;
899
900 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
901 addr->hash)) {
902 spin_unlock(&unix_table_lock);
903 /*
904 * __unix_find_socket_byname() may take long time if many names
905 * are already in use.
906 */
907 cond_resched();
908 /* Give up if all names seems to be in use. */
909 if (retries++ == 0xFFFFF) {
910 err = -ENOSPC;
911 kfree(addr);
912 goto out;
913 }
914 goto retry;
915 }
916 addr->hash ^= sk->sk_type;
917
918 __unix_remove_socket(sk);
919 smp_store_release(&u->addr, addr);
920 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
921 spin_unlock(&unix_table_lock);
922 err = 0;
923
924out: mutex_unlock(&u->bindlock);
925 return err;
926}
927
928static struct sock *unix_find_other(struct net *net,
929 struct sockaddr_un *sunname, int len,
930 int type, unsigned int hash, int *error)
931{
932 struct sock *u;
933 struct path path;
934 int err = 0;
935
936 if (sunname->sun_path[0]) {
937 struct inode *inode;
938 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
939 if (err)
940 goto fail;
941 inode = d_backing_inode(path.dentry);
942 err = inode_permission(inode, MAY_WRITE);
943 if (err)
944 goto put_fail;
945
946 err = -ECONNREFUSED;
947 if (!S_ISSOCK(inode->i_mode))
948 goto put_fail;
949 u = unix_find_socket_byinode(inode);
950 if (!u)
951 goto put_fail;
952
953 if (u->sk_type == type)
954 touch_atime(&path);
955
956 path_put(&path);
957
958 err = -EPROTOTYPE;
959 if (u->sk_type != type) {
960 sock_put(u);
961 goto fail;
962 }
963 } else {
964 err = -ECONNREFUSED;
965 u = unix_find_socket_byname(net, sunname, len, type, hash);
966 if (u) {
967 struct dentry *dentry;
968 dentry = unix_sk(u)->path.dentry;
969 if (dentry)
970 touch_atime(&unix_sk(u)->path);
971 } else
972 goto fail;
973 }
974 return u;
975
976put_fail:
977 path_put(&path);
978fail:
979 *error = err;
980 return NULL;
981}
982
983static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
984{
985 struct dentry *dentry;
986 struct path path;
987 int err = 0;
988 /*
989 * Get the parent directory, calculate the hash for last
990 * component.
991 */
992 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
993 err = PTR_ERR(dentry);
994 if (IS_ERR(dentry))
995 return err;
996
997 /*
998 * All right, let's create it.
999 */
1000 err = security_path_mknod(&path, dentry, mode, 0);
1001 if (!err) {
1002 err = vfs_mknod(d_inode(path.dentry), dentry, mode, 0);
1003 if (!err) {
1004 res->mnt = mntget(path.mnt);
1005 res->dentry = dget(dentry);
1006 }
1007 }
1008 done_path_create(&path, dentry);
1009 return err;
1010}
1011
1012static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1013{
1014 struct sock *sk = sock->sk;
1015 struct net *net = sock_net(sk);
1016 struct unix_sock *u = unix_sk(sk);
1017 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1018 char *sun_path = sunaddr->sun_path;
1019 int err;
1020 unsigned int hash;
1021 struct unix_address *addr;
1022 struct hlist_head *list;
1023 struct path path = { };
1024
1025 err = -EINVAL;
1026 if (addr_len < offsetofend(struct sockaddr_un, sun_family) ||
1027 sunaddr->sun_family != AF_UNIX)
1028 goto out;
1029
1030 if (addr_len == sizeof(short)) {
1031 err = unix_autobind(sock);
1032 goto out;
1033 }
1034
1035 err = unix_mkname(sunaddr, addr_len, &hash);
1036 if (err < 0)
1037 goto out;
1038 addr_len = err;
1039
1040 if (sun_path[0]) {
1041 umode_t mode = S_IFSOCK |
1042 (SOCK_INODE(sock)->i_mode & ~current_umask());
1043 err = unix_mknod(sun_path, mode, &path);
1044 if (err) {
1045 if (err == -EEXIST)
1046 err = -EADDRINUSE;
1047 goto out;
1048 }
1049 }
1050
1051 err = mutex_lock_interruptible(&u->bindlock);
1052 if (err)
1053 goto out_put;
1054
1055 err = -EINVAL;
1056 if (u->addr)
1057 goto out_up;
1058
1059 err = -ENOMEM;
1060 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
1061 if (!addr)
1062 goto out_up;
1063
1064 memcpy(addr->name, sunaddr, addr_len);
1065 addr->len = addr_len;
1066 addr->hash = hash ^ sk->sk_type;
1067 refcount_set(&addr->refcnt, 1);
1068
1069 if (sun_path[0]) {
1070 addr->hash = UNIX_HASH_SIZE;
1071 hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE - 1);
1072 spin_lock(&unix_table_lock);
1073 u->path = path;
1074 list = &unix_socket_table[hash];
1075 } else {
1076 spin_lock(&unix_table_lock);
1077 err = -EADDRINUSE;
1078 if (__unix_find_socket_byname(net, sunaddr, addr_len,
1079 sk->sk_type, hash)) {
1080 unix_release_addr(addr);
1081 goto out_unlock;
1082 }
1083
1084 list = &unix_socket_table[addr->hash];
1085 }
1086
1087 err = 0;
1088 __unix_remove_socket(sk);
1089 smp_store_release(&u->addr, addr);
1090 __unix_insert_socket(list, sk);
1091
1092out_unlock:
1093 spin_unlock(&unix_table_lock);
1094out_up:
1095 mutex_unlock(&u->bindlock);
1096out_put:
1097 if (err)
1098 path_put(&path);
1099out:
1100 return err;
1101}
1102
1103static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1104{
1105 if (unlikely(sk1 == sk2) || !sk2) {
1106 unix_state_lock(sk1);
1107 return;
1108 }
1109 if (sk1 < sk2) {
1110 unix_state_lock(sk1);
1111 unix_state_lock_nested(sk2);
1112 } else {
1113 unix_state_lock(sk2);
1114 unix_state_lock_nested(sk1);
1115 }
1116}
1117
1118static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1119{
1120 if (unlikely(sk1 == sk2) || !sk2) {
1121 unix_state_unlock(sk1);
1122 return;
1123 }
1124 unix_state_unlock(sk1);
1125 unix_state_unlock(sk2);
1126}
1127
1128static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1129 int alen, int flags)
1130{
1131 struct sock *sk = sock->sk;
1132 struct net *net = sock_net(sk);
1133 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1134 struct sock *other;
1135 unsigned int hash;
1136 int err;
1137
1138 err = -EINVAL;
1139 if (alen < offsetofend(struct sockaddr, sa_family))
1140 goto out;
1141
1142 if (addr->sa_family != AF_UNSPEC) {
1143 err = unix_mkname(sunaddr, alen, &hash);
1144 if (err < 0)
1145 goto out;
1146 alen = err;
1147
1148 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1149 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1150 goto out;
1151
1152restart:
1153 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1154 if (!other)
1155 goto out;
1156
1157 unix_state_double_lock(sk, other);
1158
1159 /* Apparently VFS overslept socket death. Retry. */
1160 if (sock_flag(other, SOCK_DEAD)) {
1161 unix_state_double_unlock(sk, other);
1162 sock_put(other);
1163 goto restart;
1164 }
1165
1166 err = -EPERM;
1167 if (!unix_may_send(sk, other))
1168 goto out_unlock;
1169
1170 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1171 if (err)
1172 goto out_unlock;
1173
1174 } else {
1175 /*
1176 * 1003.1g breaking connected state with AF_UNSPEC
1177 */
1178 other = NULL;
1179 unix_state_double_lock(sk, other);
1180 }
1181
1182 /*
1183 * If it was connected, reconnect.
1184 */
1185 if (unix_peer(sk)) {
1186 struct sock *old_peer = unix_peer(sk);
1187 unix_peer(sk) = other;
1188 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1189
1190 unix_state_double_unlock(sk, other);
1191
1192 if (other != old_peer)
1193 unix_dgram_disconnected(sk, old_peer);
1194 sock_put(old_peer);
1195 } else {
1196 unix_peer(sk) = other;
1197 unix_state_double_unlock(sk, other);
1198 }
1199 return 0;
1200
1201out_unlock:
1202 unix_state_double_unlock(sk, other);
1203 sock_put(other);
1204out:
1205 return err;
1206}
1207
1208static long unix_wait_for_peer(struct sock *other, long timeo)
1209 __releases(&unix_sk(other)->lock)
1210{
1211 struct unix_sock *u = unix_sk(other);
1212 int sched;
1213 DEFINE_WAIT(wait);
1214
1215 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1216
1217 sched = !sock_flag(other, SOCK_DEAD) &&
1218 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1219 unix_recvq_full(other);
1220
1221 unix_state_unlock(other);
1222
1223 if (sched)
1224 timeo = schedule_timeout(timeo);
1225
1226 finish_wait(&u->peer_wait, &wait);
1227 return timeo;
1228}
1229
1230static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1231 int addr_len, int flags)
1232{
1233 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1234 struct sock *sk = sock->sk;
1235 struct net *net = sock_net(sk);
1236 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1237 struct sock *newsk = NULL;
1238 struct sock *other = NULL;
1239 struct sk_buff *skb = NULL;
1240 unsigned int hash;
1241 int st;
1242 int err;
1243 long timeo;
1244
1245 err = unix_mkname(sunaddr, addr_len, &hash);
1246 if (err < 0)
1247 goto out;
1248 addr_len = err;
1249
1250 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1251 (err = unix_autobind(sock)) != 0)
1252 goto out;
1253
1254 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1255
1256 /* First of all allocate resources.
1257 If we will make it after state is locked,
1258 we will have to recheck all again in any case.
1259 */
1260
1261 err = -ENOMEM;
1262
1263 /* create new sock for complete connection */
1264 newsk = unix_create1(sock_net(sk), NULL, 0);
1265 if (newsk == NULL)
1266 goto out;
1267
1268 /* Allocate skb for sending to listening sock */
1269 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1270 if (skb == NULL)
1271 goto out;
1272
1273restart:
1274 /* Find listening sock. */
1275 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1276 if (!other)
1277 goto out;
1278
1279 /* Latch state of peer */
1280 unix_state_lock(other);
1281
1282 /* Apparently VFS overslept socket death. Retry. */
1283 if (sock_flag(other, SOCK_DEAD)) {
1284 unix_state_unlock(other);
1285 sock_put(other);
1286 goto restart;
1287 }
1288
1289 err = -ECONNREFUSED;
1290 if (other->sk_state != TCP_LISTEN)
1291 goto out_unlock;
1292 if (other->sk_shutdown & RCV_SHUTDOWN)
1293 goto out_unlock;
1294
1295 if (unix_recvq_full(other)) {
1296 err = -EAGAIN;
1297 if (!timeo)
1298 goto out_unlock;
1299
1300 timeo = unix_wait_for_peer(other, timeo);
1301
1302 err = sock_intr_errno(timeo);
1303 if (signal_pending(current))
1304 goto out;
1305 sock_put(other);
1306 goto restart;
1307 }
1308
1309 /* Latch our state.
1310
1311 It is tricky place. We need to grab our state lock and cannot
1312 drop lock on peer. It is dangerous because deadlock is
1313 possible. Connect to self case and simultaneous
1314 attempt to connect are eliminated by checking socket
1315 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1316 check this before attempt to grab lock.
1317
1318 Well, and we have to recheck the state after socket locked.
1319 */
1320 st = sk->sk_state;
1321
1322 switch (st) {
1323 case TCP_CLOSE:
1324 /* This is ok... continue with connect */
1325 break;
1326 case TCP_ESTABLISHED:
1327 /* Socket is already connected */
1328 err = -EISCONN;
1329 goto out_unlock;
1330 default:
1331 err = -EINVAL;
1332 goto out_unlock;
1333 }
1334
1335 unix_state_lock_nested(sk);
1336
1337 if (sk->sk_state != st) {
1338 unix_state_unlock(sk);
1339 unix_state_unlock(other);
1340 sock_put(other);
1341 goto restart;
1342 }
1343
1344 err = security_unix_stream_connect(sk, other, newsk);
1345 if (err) {
1346 unix_state_unlock(sk);
1347 goto out_unlock;
1348 }
1349
1350 /* The way is open! Fastly set all the necessary fields... */
1351
1352 sock_hold(sk);
1353 unix_peer(newsk) = sk;
1354 newsk->sk_state = TCP_ESTABLISHED;
1355 newsk->sk_type = sk->sk_type;
1356 init_peercred(newsk);
1357 newu = unix_sk(newsk);
1358 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1359 otheru = unix_sk(other);
1360
1361 /* copy address information from listening to new sock
1362 *
1363 * The contents of *(otheru->addr) and otheru->path
1364 * are seen fully set up here, since we have found
1365 * otheru in hash under unix_table_lock. Insertion
1366 * into the hash chain we'd found it in had been done
1367 * in an earlier critical area protected by unix_table_lock,
1368 * the same one where we'd set *(otheru->addr) contents,
1369 * as well as otheru->path and otheru->addr itself.
1370 *
1371 * Using smp_store_release() here to set newu->addr
1372 * is enough to make those stores, as well as stores
1373 * to newu->path visible to anyone who gets newu->addr
1374 * by smp_load_acquire(). IOW, the same warranties
1375 * as for unix_sock instances bound in unix_bind() or
1376 * in unix_autobind().
1377 */
1378 if (otheru->path.dentry) {
1379 path_get(&otheru->path);
1380 newu->path = otheru->path;
1381 }
1382 refcount_inc(&otheru->addr->refcnt);
1383 smp_store_release(&newu->addr, otheru->addr);
1384
1385 /* Set credentials */
1386 copy_peercred(sk, other);
1387
1388 sock->state = SS_CONNECTED;
1389 sk->sk_state = TCP_ESTABLISHED;
1390 sock_hold(newsk);
1391
1392 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1393 unix_peer(sk) = newsk;
1394
1395 unix_state_unlock(sk);
1396
1397 /* take ten and and send info to listening sock */
1398 spin_lock(&other->sk_receive_queue.lock);
1399 __skb_queue_tail(&other->sk_receive_queue, skb);
1400 spin_unlock(&other->sk_receive_queue.lock);
1401 unix_state_unlock(other);
1402 other->sk_data_ready(other);
1403 sock_put(other);
1404 return 0;
1405
1406out_unlock:
1407 if (other)
1408 unix_state_unlock(other);
1409
1410out:
1411 kfree_skb(skb);
1412 if (newsk)
1413 unix_release_sock(newsk, 0);
1414 if (other)
1415 sock_put(other);
1416 return err;
1417}
1418
1419static int unix_socketpair(struct socket *socka, struct socket *sockb)
1420{
1421 struct sock *ska = socka->sk, *skb = sockb->sk;
1422
1423 /* Join our sockets back to back */
1424 sock_hold(ska);
1425 sock_hold(skb);
1426 unix_peer(ska) = skb;
1427 unix_peer(skb) = ska;
1428 init_peercred(ska);
1429 init_peercred(skb);
1430
1431 if (ska->sk_type != SOCK_DGRAM) {
1432 ska->sk_state = TCP_ESTABLISHED;
1433 skb->sk_state = TCP_ESTABLISHED;
1434 socka->state = SS_CONNECTED;
1435 sockb->state = SS_CONNECTED;
1436 }
1437 return 0;
1438}
1439
1440static void unix_sock_inherit_flags(const struct socket *old,
1441 struct socket *new)
1442{
1443 if (test_bit(SOCK_PASSCRED, &old->flags))
1444 set_bit(SOCK_PASSCRED, &new->flags);
1445 if (test_bit(SOCK_PASSSEC, &old->flags))
1446 set_bit(SOCK_PASSSEC, &new->flags);
1447}
1448
1449static int unix_accept(struct socket *sock, struct socket *newsock, int flags,
1450 bool kern)
1451{
1452 struct sock *sk = sock->sk;
1453 struct sock *tsk;
1454 struct sk_buff *skb;
1455 int err;
1456
1457 err = -EOPNOTSUPP;
1458 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1459 goto out;
1460
1461 err = -EINVAL;
1462 if (sk->sk_state != TCP_LISTEN)
1463 goto out;
1464
1465 /* If socket state is TCP_LISTEN it cannot change (for now...),
1466 * so that no locks are necessary.
1467 */
1468
1469 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1470 if (!skb) {
1471 /* This means receive shutdown. */
1472 if (err == 0)
1473 err = -EINVAL;
1474 goto out;
1475 }
1476
1477 tsk = skb->sk;
1478 skb_free_datagram(sk, skb);
1479 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1480
1481 /* attach accepted sock to socket */
1482 unix_state_lock(tsk);
1483 newsock->state = SS_CONNECTED;
1484 unix_sock_inherit_flags(sock, newsock);
1485 sock_graft(tsk, newsock);
1486 unix_state_unlock(tsk);
1487 return 0;
1488
1489out:
1490 return err;
1491}
1492
1493
1494static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1495{
1496 struct sock *sk = sock->sk;
1497 struct unix_address *addr;
1498 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1499 int err = 0;
1500
1501 if (peer) {
1502 sk = unix_peer_get(sk);
1503
1504 err = -ENOTCONN;
1505 if (!sk)
1506 goto out;
1507 err = 0;
1508 } else {
1509 sock_hold(sk);
1510 }
1511
1512 addr = smp_load_acquire(&unix_sk(sk)->addr);
1513 if (!addr) {
1514 sunaddr->sun_family = AF_UNIX;
1515 sunaddr->sun_path[0] = 0;
1516 err = sizeof(short);
1517 } else {
1518 err = addr->len;
1519 memcpy(sunaddr, addr->name, addr->len);
1520 }
1521 sock_put(sk);
1522out:
1523 return err;
1524}
1525
1526static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1527{
1528 int err = 0;
1529
1530 UNIXCB(skb).pid = get_pid(scm->pid);
1531 UNIXCB(skb).uid = scm->creds.uid;
1532 UNIXCB(skb).gid = scm->creds.gid;
1533 UNIXCB(skb).fp = NULL;
1534 unix_get_secdata(scm, skb);
1535 if (scm->fp && send_fds)
1536 err = unix_attach_fds(scm, skb);
1537
1538 skb->destructor = unix_destruct_scm;
1539 return err;
1540}
1541
1542static bool unix_passcred_enabled(const struct socket *sock,
1543 const struct sock *other)
1544{
1545 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1546 !other->sk_socket ||
1547 test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1548}
1549
1550/*
1551 * Some apps rely on write() giving SCM_CREDENTIALS
1552 * We include credentials if source or destination socket
1553 * asserted SOCK_PASSCRED.
1554 */
1555static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1556 const struct sock *other)
1557{
1558 if (UNIXCB(skb).pid)
1559 return;
1560 if (unix_passcred_enabled(sock, other)) {
1561 UNIXCB(skb).pid = get_pid(task_tgid(current));
1562 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1563 }
1564}
1565
1566static int maybe_init_creds(struct scm_cookie *scm,
1567 struct socket *socket,
1568 const struct sock *other)
1569{
1570 int err;
1571 struct msghdr msg = { .msg_controllen = 0 };
1572
1573 err = scm_send(socket, &msg, scm, false);
1574 if (err)
1575 return err;
1576
1577 if (unix_passcred_enabled(socket, other)) {
1578 scm->pid = get_pid(task_tgid(current));
1579 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1580 }
1581 return err;
1582}
1583
1584static bool unix_skb_scm_eq(struct sk_buff *skb,
1585 struct scm_cookie *scm)
1586{
1587 const struct unix_skb_parms *u = &UNIXCB(skb);
1588
1589 return u->pid == scm->pid &&
1590 uid_eq(u->uid, scm->creds.uid) &&
1591 gid_eq(u->gid, scm->creds.gid) &&
1592 unix_secdata_eq(scm, skb);
1593}
1594
1595static void scm_stat_add(struct sock *sk, struct sk_buff *skb)
1596{
1597 struct scm_fp_list *fp = UNIXCB(skb).fp;
1598 struct unix_sock *u = unix_sk(sk);
1599
1600 if (unlikely(fp && fp->count))
1601 atomic_add(fp->count, &u->scm_stat.nr_fds);
1602}
1603
1604static void scm_stat_del(struct sock *sk, struct sk_buff *skb)
1605{
1606 struct scm_fp_list *fp = UNIXCB(skb).fp;
1607 struct unix_sock *u = unix_sk(sk);
1608
1609 if (unlikely(fp && fp->count))
1610 atomic_sub(fp->count, &u->scm_stat.nr_fds);
1611}
1612
1613/*
1614 * Send AF_UNIX data.
1615 */
1616
1617static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1618 size_t len)
1619{
1620 struct sock *sk = sock->sk;
1621 struct net *net = sock_net(sk);
1622 struct unix_sock *u = unix_sk(sk);
1623 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1624 struct sock *other = NULL;
1625 int namelen = 0; /* fake GCC */
1626 int err;
1627 unsigned int hash;
1628 struct sk_buff *skb;
1629 long timeo;
1630 struct scm_cookie scm;
1631 int data_len = 0;
1632 int sk_locked;
1633
1634 wait_for_unix_gc();
1635 err = scm_send(sock, msg, &scm, false);
1636 if (err < 0)
1637 return err;
1638
1639 err = -EOPNOTSUPP;
1640 if (msg->msg_flags&MSG_OOB)
1641 goto out;
1642
1643 if (msg->msg_namelen) {
1644 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1645 if (err < 0)
1646 goto out;
1647 namelen = err;
1648 } else {
1649 sunaddr = NULL;
1650 err = -ENOTCONN;
1651 other = unix_peer_get(sk);
1652 if (!other)
1653 goto out;
1654 }
1655
1656 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1657 && (err = unix_autobind(sock)) != 0)
1658 goto out;
1659
1660 err = -EMSGSIZE;
1661 if (len > sk->sk_sndbuf - 32)
1662 goto out;
1663
1664 if (len > SKB_MAX_ALLOC) {
1665 data_len = min_t(size_t,
1666 len - SKB_MAX_ALLOC,
1667 MAX_SKB_FRAGS * PAGE_SIZE);
1668 data_len = PAGE_ALIGN(data_len);
1669
1670 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1671 }
1672
1673 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1674 msg->msg_flags & MSG_DONTWAIT, &err,
1675 PAGE_ALLOC_COSTLY_ORDER);
1676 if (skb == NULL)
1677 goto out;
1678
1679 err = unix_scm_to_skb(&scm, skb, true);
1680 if (err < 0)
1681 goto out_free;
1682
1683 skb_put(skb, len - data_len);
1684 skb->data_len = data_len;
1685 skb->len = len;
1686 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1687 if (err)
1688 goto out_free;
1689
1690 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1691
1692restart:
1693 if (!other) {
1694 err = -ECONNRESET;
1695 if (sunaddr == NULL)
1696 goto out_free;
1697
1698 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1699 hash, &err);
1700 if (other == NULL)
1701 goto out_free;
1702 }
1703
1704 if (sk_filter(other, skb) < 0) {
1705 /* Toss the packet but do not return any error to the sender */
1706 err = len;
1707 goto out_free;
1708 }
1709
1710 sk_locked = 0;
1711 unix_state_lock(other);
1712restart_locked:
1713 err = -EPERM;
1714 if (!unix_may_send(sk, other))
1715 goto out_unlock;
1716
1717 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1718 /*
1719 * Check with 1003.1g - what should
1720 * datagram error
1721 */
1722 unix_state_unlock(other);
1723 sock_put(other);
1724
1725 if (!sk_locked)
1726 unix_state_lock(sk);
1727
1728 err = 0;
1729 if (unix_peer(sk) == other) {
1730 unix_peer(sk) = NULL;
1731 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1732
1733 unix_state_unlock(sk);
1734
1735 unix_dgram_disconnected(sk, other);
1736 sock_put(other);
1737 err = -ECONNREFUSED;
1738 } else {
1739 unix_state_unlock(sk);
1740 }
1741
1742 other = NULL;
1743 if (err)
1744 goto out_free;
1745 goto restart;
1746 }
1747
1748 err = -EPIPE;
1749 if (other->sk_shutdown & RCV_SHUTDOWN)
1750 goto out_unlock;
1751
1752 if (sk->sk_type != SOCK_SEQPACKET) {
1753 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1754 if (err)
1755 goto out_unlock;
1756 }
1757
1758 /* other == sk && unix_peer(other) != sk if
1759 * - unix_peer(sk) == NULL, destination address bound to sk
1760 * - unix_peer(sk) == sk by time of get but disconnected before lock
1761 */
1762 if (other != sk &&
1763 unlikely(unix_peer(other) != sk &&
1764 unix_recvq_full_lockless(other))) {
1765 if (timeo) {
1766 timeo = unix_wait_for_peer(other, timeo);
1767
1768 err = sock_intr_errno(timeo);
1769 if (signal_pending(current))
1770 goto out_free;
1771
1772 goto restart;
1773 }
1774
1775 if (!sk_locked) {
1776 unix_state_unlock(other);
1777 unix_state_double_lock(sk, other);
1778 }
1779
1780 if (unix_peer(sk) != other ||
1781 unix_dgram_peer_wake_me(sk, other)) {
1782 err = -EAGAIN;
1783 sk_locked = 1;
1784 goto out_unlock;
1785 }
1786
1787 if (!sk_locked) {
1788 sk_locked = 1;
1789 goto restart_locked;
1790 }
1791 }
1792
1793 if (unlikely(sk_locked))
1794 unix_state_unlock(sk);
1795
1796 if (sock_flag(other, SOCK_RCVTSTAMP))
1797 __net_timestamp(skb);
1798 maybe_add_creds(skb, sock, other);
1799 scm_stat_add(other, skb);
1800 skb_queue_tail(&other->sk_receive_queue, skb);
1801 unix_state_unlock(other);
1802 other->sk_data_ready(other);
1803 sock_put(other);
1804 scm_destroy(&scm);
1805 return len;
1806
1807out_unlock:
1808 if (sk_locked)
1809 unix_state_unlock(sk);
1810 unix_state_unlock(other);
1811out_free:
1812 kfree_skb(skb);
1813out:
1814 if (other)
1815 sock_put(other);
1816 scm_destroy(&scm);
1817 return err;
1818}
1819
1820/* We use paged skbs for stream sockets, and limit occupancy to 32768
1821 * bytes, and a minimum of a full page.
1822 */
1823#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1824
1825static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
1826 size_t len)
1827{
1828 struct sock *sk = sock->sk;
1829 struct sock *other = NULL;
1830 int err, size;
1831 struct sk_buff *skb;
1832 int sent = 0;
1833 struct scm_cookie scm;
1834 bool fds_sent = false;
1835 int data_len;
1836
1837 wait_for_unix_gc();
1838 err = scm_send(sock, msg, &scm, false);
1839 if (err < 0)
1840 return err;
1841
1842 err = -EOPNOTSUPP;
1843 if (msg->msg_flags&MSG_OOB)
1844 goto out_err;
1845
1846 if (msg->msg_namelen) {
1847 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1848 goto out_err;
1849 } else {
1850 err = -ENOTCONN;
1851 other = unix_peer(sk);
1852 if (!other)
1853 goto out_err;
1854 }
1855
1856 if (sk->sk_shutdown & SEND_SHUTDOWN)
1857 goto pipe_err;
1858
1859 while (sent < len) {
1860 size = len - sent;
1861
1862 /* Keep two messages in the pipe so it schedules better */
1863 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1864
1865 /* allow fallback to order-0 allocations */
1866 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1867
1868 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1869
1870 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
1871
1872 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1873 msg->msg_flags & MSG_DONTWAIT, &err,
1874 get_order(UNIX_SKB_FRAGS_SZ));
1875 if (!skb)
1876 goto out_err;
1877
1878 /* Only send the fds in the first buffer */
1879 err = unix_scm_to_skb(&scm, skb, !fds_sent);
1880 if (err < 0) {
1881 kfree_skb(skb);
1882 goto out_err;
1883 }
1884 fds_sent = true;
1885
1886 skb_put(skb, size - data_len);
1887 skb->data_len = data_len;
1888 skb->len = size;
1889 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
1890 if (err) {
1891 kfree_skb(skb);
1892 goto out_err;
1893 }
1894
1895 unix_state_lock(other);
1896
1897 if (sock_flag(other, SOCK_DEAD) ||
1898 (other->sk_shutdown & RCV_SHUTDOWN))
1899 goto pipe_err_free;
1900
1901 maybe_add_creds(skb, sock, other);
1902 scm_stat_add(other, skb);
1903 skb_queue_tail(&other->sk_receive_queue, skb);
1904 unix_state_unlock(other);
1905 other->sk_data_ready(other);
1906 sent += size;
1907 }
1908
1909 scm_destroy(&scm);
1910
1911 return sent;
1912
1913pipe_err_free:
1914 unix_state_unlock(other);
1915 kfree_skb(skb);
1916pipe_err:
1917 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1918 send_sig(SIGPIPE, current, 0);
1919 err = -EPIPE;
1920out_err:
1921 scm_destroy(&scm);
1922 return sent ? : err;
1923}
1924
1925static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
1926 int offset, size_t size, int flags)
1927{
1928 int err;
1929 bool send_sigpipe = false;
1930 bool init_scm = true;
1931 struct scm_cookie scm;
1932 struct sock *other, *sk = socket->sk;
1933 struct sk_buff *skb, *newskb = NULL, *tail = NULL;
1934
1935 if (flags & MSG_OOB)
1936 return -EOPNOTSUPP;
1937
1938 other = unix_peer(sk);
1939 if (!other || sk->sk_state != TCP_ESTABLISHED)
1940 return -ENOTCONN;
1941
1942 if (false) {
1943alloc_skb:
1944 unix_state_unlock(other);
1945 mutex_unlock(&unix_sk(other)->iolock);
1946 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
1947 &err, 0);
1948 if (!newskb)
1949 goto err;
1950 }
1951
1952 /* we must acquire iolock as we modify already present
1953 * skbs in the sk_receive_queue and mess with skb->len
1954 */
1955 err = mutex_lock_interruptible(&unix_sk(other)->iolock);
1956 if (err) {
1957 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
1958 goto err;
1959 }
1960
1961 if (sk->sk_shutdown & SEND_SHUTDOWN) {
1962 err = -EPIPE;
1963 send_sigpipe = true;
1964 goto err_unlock;
1965 }
1966
1967 unix_state_lock(other);
1968
1969 if (sock_flag(other, SOCK_DEAD) ||
1970 other->sk_shutdown & RCV_SHUTDOWN) {
1971 err = -EPIPE;
1972 send_sigpipe = true;
1973 goto err_state_unlock;
1974 }
1975
1976 if (init_scm) {
1977 err = maybe_init_creds(&scm, socket, other);
1978 if (err)
1979 goto err_state_unlock;
1980 init_scm = false;
1981 }
1982
1983 skb = skb_peek_tail(&other->sk_receive_queue);
1984 if (tail && tail == skb) {
1985 skb = newskb;
1986 } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
1987 if (newskb) {
1988 skb = newskb;
1989 } else {
1990 tail = skb;
1991 goto alloc_skb;
1992 }
1993 } else if (newskb) {
1994 /* this is fast path, we don't necessarily need to
1995 * call to kfree_skb even though with newskb == NULL
1996 * this - does no harm
1997 */
1998 consume_skb(newskb);
1999 newskb = NULL;
2000 }
2001
2002 if (skb_append_pagefrags(skb, page, offset, size)) {
2003 tail = skb;
2004 goto alloc_skb;
2005 }
2006
2007 skb->len += size;
2008 skb->data_len += size;
2009 skb->truesize += size;
2010 refcount_add(size, &sk->sk_wmem_alloc);
2011
2012 if (newskb) {
2013 err = unix_scm_to_skb(&scm, skb, false);
2014 if (err)
2015 goto err_state_unlock;
2016 spin_lock(&other->sk_receive_queue.lock);
2017 __skb_queue_tail(&other->sk_receive_queue, newskb);
2018 spin_unlock(&other->sk_receive_queue.lock);
2019 }
2020
2021 unix_state_unlock(other);
2022 mutex_unlock(&unix_sk(other)->iolock);
2023
2024 other->sk_data_ready(other);
2025 scm_destroy(&scm);
2026 return size;
2027
2028err_state_unlock:
2029 unix_state_unlock(other);
2030err_unlock:
2031 mutex_unlock(&unix_sk(other)->iolock);
2032err:
2033 kfree_skb(newskb);
2034 if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2035 send_sig(SIGPIPE, current, 0);
2036 if (!init_scm)
2037 scm_destroy(&scm);
2038 return err;
2039}
2040
2041static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2042 size_t len)
2043{
2044 int err;
2045 struct sock *sk = sock->sk;
2046
2047 err = sock_error(sk);
2048 if (err)
2049 return err;
2050
2051 if (sk->sk_state != TCP_ESTABLISHED)
2052 return -ENOTCONN;
2053
2054 if (msg->msg_namelen)
2055 msg->msg_namelen = 0;
2056
2057 return unix_dgram_sendmsg(sock, msg, len);
2058}
2059
2060static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2061 size_t size, int flags)
2062{
2063 struct sock *sk = sock->sk;
2064
2065 if (sk->sk_state != TCP_ESTABLISHED)
2066 return -ENOTCONN;
2067
2068 return unix_dgram_recvmsg(sock, msg, size, flags);
2069}
2070
2071static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2072{
2073 struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
2074
2075 if (addr) {
2076 msg->msg_namelen = addr->len;
2077 memcpy(msg->msg_name, addr->name, addr->len);
2078 }
2079}
2080
2081static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
2082 size_t size, int flags)
2083{
2084 struct scm_cookie scm;
2085 struct sock *sk = sock->sk;
2086 struct unix_sock *u = unix_sk(sk);
2087 struct sk_buff *skb, *last;
2088 long timeo;
2089 int skip;
2090 int err;
2091
2092 err = -EOPNOTSUPP;
2093 if (flags&MSG_OOB)
2094 goto out;
2095
2096 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2097
2098 do {
2099 mutex_lock(&u->iolock);
2100
2101 skip = sk_peek_offset(sk, flags);
2102 skb = __skb_try_recv_datagram(sk, &sk->sk_receive_queue, flags,
2103 &skip, &err, &last);
2104 if (skb) {
2105 if (!(flags & MSG_PEEK))
2106 scm_stat_del(sk, skb);
2107 break;
2108 }
2109
2110 mutex_unlock(&u->iolock);
2111
2112 if (err != -EAGAIN)
2113 break;
2114 } while (timeo &&
2115 !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue,
2116 &err, &timeo, last));
2117
2118 if (!skb) { /* implies iolock unlocked */
2119 unix_state_lock(sk);
2120 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2121 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2122 (sk->sk_shutdown & RCV_SHUTDOWN))
2123 err = 0;
2124 unix_state_unlock(sk);
2125 goto out;
2126 }
2127
2128 if (wq_has_sleeper(&u->peer_wait))
2129 wake_up_interruptible_sync_poll(&u->peer_wait,
2130 EPOLLOUT | EPOLLWRNORM |
2131 EPOLLWRBAND);
2132
2133 if (msg->msg_name)
2134 unix_copy_addr(msg, skb->sk);
2135
2136 if (size > skb->len - skip)
2137 size = skb->len - skip;
2138 else if (size < skb->len - skip)
2139 msg->msg_flags |= MSG_TRUNC;
2140
2141 err = skb_copy_datagram_msg(skb, skip, msg, size);
2142 if (err)
2143 goto out_free;
2144
2145 if (sock_flag(sk, SOCK_RCVTSTAMP))
2146 __sock_recv_timestamp(msg, sk, skb);
2147
2148 memset(&scm, 0, sizeof(scm));
2149
2150 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2151 unix_set_secdata(&scm, skb);
2152
2153 if (!(flags & MSG_PEEK)) {
2154 if (UNIXCB(skb).fp)
2155 unix_detach_fds(&scm, skb);
2156
2157 sk_peek_offset_bwd(sk, skb->len);
2158 } else {
2159 /* It is questionable: on PEEK we could:
2160 - do not return fds - good, but too simple 8)
2161 - return fds, and do not return them on read (old strategy,
2162 apparently wrong)
2163 - clone fds (I chose it for now, it is the most universal
2164 solution)
2165
2166 POSIX 1003.1g does not actually define this clearly
2167 at all. POSIX 1003.1g doesn't define a lot of things
2168 clearly however!
2169
2170 */
2171
2172 sk_peek_offset_fwd(sk, size);
2173
2174 if (UNIXCB(skb).fp)
2175 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2176 }
2177 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2178
2179 scm_recv(sock, msg, &scm, flags);
2180
2181out_free:
2182 skb_free_datagram(sk, skb);
2183 mutex_unlock(&u->iolock);
2184out:
2185 return err;
2186}
2187
2188/*
2189 * Sleep until more data has arrived. But check for races..
2190 */
2191static long unix_stream_data_wait(struct sock *sk, long timeo,
2192 struct sk_buff *last, unsigned int last_len,
2193 bool freezable)
2194{
2195 struct sk_buff *tail;
2196 DEFINE_WAIT(wait);
2197
2198 unix_state_lock(sk);
2199
2200 for (;;) {
2201 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2202
2203 tail = skb_peek_tail(&sk->sk_receive_queue);
2204 if (tail != last ||
2205 (tail && tail->len != last_len) ||
2206 sk->sk_err ||
2207 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2208 signal_pending(current) ||
2209 !timeo)
2210 break;
2211
2212 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2213 unix_state_unlock(sk);
2214 if (freezable)
2215 timeo = freezable_schedule_timeout(timeo);
2216 else
2217 timeo = schedule_timeout(timeo);
2218 unix_state_lock(sk);
2219
2220 if (sock_flag(sk, SOCK_DEAD))
2221 break;
2222
2223 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2224 }
2225
2226 finish_wait(sk_sleep(sk), &wait);
2227 unix_state_unlock(sk);
2228 return timeo;
2229}
2230
2231static unsigned int unix_skb_len(const struct sk_buff *skb)
2232{
2233 return skb->len - UNIXCB(skb).consumed;
2234}
2235
2236struct unix_stream_read_state {
2237 int (*recv_actor)(struct sk_buff *, int, int,
2238 struct unix_stream_read_state *);
2239 struct socket *socket;
2240 struct msghdr *msg;
2241 struct pipe_inode_info *pipe;
2242 size_t size;
2243 int flags;
2244 unsigned int splice_flags;
2245};
2246
2247static int unix_stream_read_generic(struct unix_stream_read_state *state,
2248 bool freezable)
2249{
2250 struct scm_cookie scm;
2251 struct socket *sock = state->socket;
2252 struct sock *sk = sock->sk;
2253 struct unix_sock *u = unix_sk(sk);
2254 int copied = 0;
2255 int flags = state->flags;
2256 int noblock = flags & MSG_DONTWAIT;
2257 bool check_creds = false;
2258 int target;
2259 int err = 0;
2260 long timeo;
2261 int skip;
2262 size_t size = state->size;
2263 unsigned int last_len;
2264
2265 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2266 err = -EINVAL;
2267 goto out;
2268 }
2269
2270 if (unlikely(flags & MSG_OOB)) {
2271 err = -EOPNOTSUPP;
2272 goto out;
2273 }
2274
2275 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2276 timeo = sock_rcvtimeo(sk, noblock);
2277
2278 memset(&scm, 0, sizeof(scm));
2279
2280 /* Lock the socket to prevent queue disordering
2281 * while sleeps in memcpy_tomsg
2282 */
2283 mutex_lock(&u->iolock);
2284
2285 skip = max(sk_peek_offset(sk, flags), 0);
2286
2287 do {
2288 int chunk;
2289 bool drop_skb;
2290 struct sk_buff *skb, *last;
2291
2292redo:
2293 unix_state_lock(sk);
2294 if (sock_flag(sk, SOCK_DEAD)) {
2295 err = -ECONNRESET;
2296 goto unlock;
2297 }
2298 last = skb = skb_peek(&sk->sk_receive_queue);
2299 last_len = last ? last->len : 0;
2300again:
2301 if (skb == NULL) {
2302 if (copied >= target)
2303 goto unlock;
2304
2305 /*
2306 * POSIX 1003.1g mandates this order.
2307 */
2308
2309 err = sock_error(sk);
2310 if (err)
2311 goto unlock;
2312 if (sk->sk_shutdown & RCV_SHUTDOWN)
2313 goto unlock;
2314
2315 unix_state_unlock(sk);
2316 if (!timeo) {
2317 err = -EAGAIN;
2318 break;
2319 }
2320
2321 mutex_unlock(&u->iolock);
2322
2323 timeo = unix_stream_data_wait(sk, timeo, last,
2324 last_len, freezable);
2325
2326 if (signal_pending(current)) {
2327 err = sock_intr_errno(timeo);
2328 scm_destroy(&scm);
2329 goto out;
2330 }
2331
2332 mutex_lock(&u->iolock);
2333 goto redo;
2334unlock:
2335 unix_state_unlock(sk);
2336 break;
2337 }
2338
2339 while (skip >= unix_skb_len(skb)) {
2340 skip -= unix_skb_len(skb);
2341 last = skb;
2342 last_len = skb->len;
2343 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2344 if (!skb)
2345 goto again;
2346 }
2347
2348 unix_state_unlock(sk);
2349
2350 if (check_creds) {
2351 /* Never glue messages from different writers */
2352 if (!unix_skb_scm_eq(skb, &scm))
2353 break;
2354 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2355 /* Copy credentials */
2356 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2357 unix_set_secdata(&scm, skb);
2358 check_creds = true;
2359 }
2360
2361 /* Copy address just once */
2362 if (state->msg && state->msg->msg_name) {
2363 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2364 state->msg->msg_name);
2365 unix_copy_addr(state->msg, skb->sk);
2366 sunaddr = NULL;
2367 }
2368
2369 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2370 skb_get(skb);
2371 chunk = state->recv_actor(skb, skip, chunk, state);
2372 drop_skb = !unix_skb_len(skb);
2373 /* skb is only safe to use if !drop_skb */
2374 consume_skb(skb);
2375 if (chunk < 0) {
2376 if (copied == 0)
2377 copied = -EFAULT;
2378 break;
2379 }
2380 copied += chunk;
2381 size -= chunk;
2382
2383 if (drop_skb) {
2384 /* the skb was touched by a concurrent reader;
2385 * we should not expect anything from this skb
2386 * anymore and assume it invalid - we can be
2387 * sure it was dropped from the socket queue
2388 *
2389 * let's report a short read
2390 */
2391 err = 0;
2392 break;
2393 }
2394
2395 /* Mark read part of skb as used */
2396 if (!(flags & MSG_PEEK)) {
2397 UNIXCB(skb).consumed += chunk;
2398
2399 sk_peek_offset_bwd(sk, chunk);
2400
2401 if (UNIXCB(skb).fp) {
2402 scm_stat_del(sk, skb);
2403 unix_detach_fds(&scm, skb);
2404 }
2405
2406 if (unix_skb_len(skb))
2407 break;
2408
2409 skb_unlink(skb, &sk->sk_receive_queue);
2410 consume_skb(skb);
2411
2412 if (scm.fp)
2413 break;
2414 } else {
2415 /* It is questionable, see note in unix_dgram_recvmsg.
2416 */
2417 if (UNIXCB(skb).fp)
2418 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2419
2420 sk_peek_offset_fwd(sk, chunk);
2421
2422 if (UNIXCB(skb).fp)
2423 break;
2424
2425 skip = 0;
2426 last = skb;
2427 last_len = skb->len;
2428 unix_state_lock(sk);
2429 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2430 if (skb)
2431 goto again;
2432 unix_state_unlock(sk);
2433 break;
2434 }
2435 } while (size);
2436
2437 mutex_unlock(&u->iolock);
2438 if (state->msg)
2439 scm_recv(sock, state->msg, &scm, flags);
2440 else
2441 scm_destroy(&scm);
2442out:
2443 return copied ? : err;
2444}
2445
2446static int unix_stream_read_actor(struct sk_buff *skb,
2447 int skip, int chunk,
2448 struct unix_stream_read_state *state)
2449{
2450 int ret;
2451
2452 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2453 state->msg, chunk);
2454 return ret ?: chunk;
2455}
2456
2457static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2458 size_t size, int flags)
2459{
2460 struct unix_stream_read_state state = {
2461 .recv_actor = unix_stream_read_actor,
2462 .socket = sock,
2463 .msg = msg,
2464 .size = size,
2465 .flags = flags
2466 };
2467
2468 return unix_stream_read_generic(&state, true);
2469}
2470
2471static int unix_stream_splice_actor(struct sk_buff *skb,
2472 int skip, int chunk,
2473 struct unix_stream_read_state *state)
2474{
2475 return skb_splice_bits(skb, state->socket->sk,
2476 UNIXCB(skb).consumed + skip,
2477 state->pipe, chunk, state->splice_flags);
2478}
2479
2480static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2481 struct pipe_inode_info *pipe,
2482 size_t size, unsigned int flags)
2483{
2484 struct unix_stream_read_state state = {
2485 .recv_actor = unix_stream_splice_actor,
2486 .socket = sock,
2487 .pipe = pipe,
2488 .size = size,
2489 .splice_flags = flags,
2490 };
2491
2492 if (unlikely(*ppos))
2493 return -ESPIPE;
2494
2495 if (sock->file->f_flags & O_NONBLOCK ||
2496 flags & SPLICE_F_NONBLOCK)
2497 state.flags = MSG_DONTWAIT;
2498
2499 return unix_stream_read_generic(&state, false);
2500}
2501
2502static int unix_shutdown(struct socket *sock, int mode)
2503{
2504 struct sock *sk = sock->sk;
2505 struct sock *other;
2506
2507 if (mode < SHUT_RD || mode > SHUT_RDWR)
2508 return -EINVAL;
2509 /* This maps:
2510 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2511 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2512 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2513 */
2514 ++mode;
2515
2516 unix_state_lock(sk);
2517 sk->sk_shutdown |= mode;
2518 other = unix_peer(sk);
2519 if (other)
2520 sock_hold(other);
2521 unix_state_unlock(sk);
2522 sk->sk_state_change(sk);
2523
2524 if (other &&
2525 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2526
2527 int peer_mode = 0;
2528
2529 if (mode&RCV_SHUTDOWN)
2530 peer_mode |= SEND_SHUTDOWN;
2531 if (mode&SEND_SHUTDOWN)
2532 peer_mode |= RCV_SHUTDOWN;
2533 unix_state_lock(other);
2534 other->sk_shutdown |= peer_mode;
2535 unix_state_unlock(other);
2536 other->sk_state_change(other);
2537 if (peer_mode == SHUTDOWN_MASK)
2538 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2539 else if (peer_mode & RCV_SHUTDOWN)
2540 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2541 }
2542 if (other)
2543 sock_put(other);
2544
2545 return 0;
2546}
2547
2548long unix_inq_len(struct sock *sk)
2549{
2550 struct sk_buff *skb;
2551 long amount = 0;
2552
2553 if (sk->sk_state == TCP_LISTEN)
2554 return -EINVAL;
2555
2556 spin_lock(&sk->sk_receive_queue.lock);
2557 if (sk->sk_type == SOCK_STREAM ||
2558 sk->sk_type == SOCK_SEQPACKET) {
2559 skb_queue_walk(&sk->sk_receive_queue, skb)
2560 amount += unix_skb_len(skb);
2561 } else {
2562 skb = skb_peek(&sk->sk_receive_queue);
2563 if (skb)
2564 amount = skb->len;
2565 }
2566 spin_unlock(&sk->sk_receive_queue.lock);
2567
2568 return amount;
2569}
2570EXPORT_SYMBOL_GPL(unix_inq_len);
2571
2572long unix_outq_len(struct sock *sk)
2573{
2574 return sk_wmem_alloc_get(sk);
2575}
2576EXPORT_SYMBOL_GPL(unix_outq_len);
2577
2578static int unix_open_file(struct sock *sk)
2579{
2580 struct path path;
2581 struct file *f;
2582 int fd;
2583
2584 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
2585 return -EPERM;
2586
2587 if (!smp_load_acquire(&unix_sk(sk)->addr))
2588 return -ENOENT;
2589
2590 path = unix_sk(sk)->path;
2591 if (!path.dentry)
2592 return -ENOENT;
2593
2594 path_get(&path);
2595
2596 fd = get_unused_fd_flags(O_CLOEXEC);
2597 if (fd < 0)
2598 goto out;
2599
2600 f = dentry_open(&path, O_PATH, current_cred());
2601 if (IS_ERR(f)) {
2602 put_unused_fd(fd);
2603 fd = PTR_ERR(f);
2604 goto out;
2605 }
2606
2607 fd_install(fd, f);
2608out:
2609 path_put(&path);
2610
2611 return fd;
2612}
2613
2614static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2615{
2616 struct sock *sk = sock->sk;
2617 long amount = 0;
2618 int err;
2619
2620 switch (cmd) {
2621 case SIOCOUTQ:
2622 amount = unix_outq_len(sk);
2623 err = put_user(amount, (int __user *)arg);
2624 break;
2625 case SIOCINQ:
2626 amount = unix_inq_len(sk);
2627 if (amount < 0)
2628 err = amount;
2629 else
2630 err = put_user(amount, (int __user *)arg);
2631 break;
2632 case SIOCUNIXFILE:
2633 err = unix_open_file(sk);
2634 break;
2635 default:
2636 err = -ENOIOCTLCMD;
2637 break;
2638 }
2639 return err;
2640}
2641
2642#ifdef CONFIG_COMPAT
2643static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2644{
2645 return unix_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
2646}
2647#endif
2648
2649static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2650{
2651 struct sock *sk = sock->sk;
2652 __poll_t mask;
2653
2654 sock_poll_wait(file, sock, wait);
2655 mask = 0;
2656
2657 /* exceptional events? */
2658 if (sk->sk_err)
2659 mask |= EPOLLERR;
2660 if (sk->sk_shutdown == SHUTDOWN_MASK)
2661 mask |= EPOLLHUP;
2662 if (sk->sk_shutdown & RCV_SHUTDOWN)
2663 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2664
2665 /* readable? */
2666 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
2667 mask |= EPOLLIN | EPOLLRDNORM;
2668
2669 /* Connection-based need to check for termination and startup */
2670 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2671 sk->sk_state == TCP_CLOSE)
2672 mask |= EPOLLHUP;
2673
2674 /*
2675 * we set writable also when the other side has shut down the
2676 * connection. This prevents stuck sockets.
2677 */
2678 if (unix_writable(sk))
2679 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
2680
2681 return mask;
2682}
2683
2684static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
2685 poll_table *wait)
2686{
2687 struct sock *sk = sock->sk, *other;
2688 unsigned int writable;
2689 __poll_t mask;
2690
2691 sock_poll_wait(file, sock, wait);
2692 mask = 0;
2693
2694 /* exceptional events? */
2695 if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
2696 mask |= EPOLLERR |
2697 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
2698
2699 if (sk->sk_shutdown & RCV_SHUTDOWN)
2700 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2701 if (sk->sk_shutdown == SHUTDOWN_MASK)
2702 mask |= EPOLLHUP;
2703
2704 /* readable? */
2705 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
2706 mask |= EPOLLIN | EPOLLRDNORM;
2707
2708 /* Connection-based need to check for termination and startup */
2709 if (sk->sk_type == SOCK_SEQPACKET) {
2710 if (sk->sk_state == TCP_CLOSE)
2711 mask |= EPOLLHUP;
2712 /* connection hasn't started yet? */
2713 if (sk->sk_state == TCP_SYN_SENT)
2714 return mask;
2715 }
2716
2717 /* No write status requested, avoid expensive OUT tests. */
2718 if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT)))
2719 return mask;
2720
2721 writable = unix_writable(sk);
2722 if (writable) {
2723 unix_state_lock(sk);
2724
2725 other = unix_peer(sk);
2726 if (other && unix_peer(other) != sk &&
2727 unix_recvq_full(other) &&
2728 unix_dgram_peer_wake_me(sk, other))
2729 writable = 0;
2730
2731 unix_state_unlock(sk);
2732 }
2733
2734 if (writable)
2735 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
2736 else
2737 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2738
2739 return mask;
2740}
2741
2742#ifdef CONFIG_PROC_FS
2743
2744#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2745
2746#define get_bucket(x) ((x) >> BUCKET_SPACE)
2747#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2748#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2749
2750static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2751{
2752 unsigned long offset = get_offset(*pos);
2753 unsigned long bucket = get_bucket(*pos);
2754 struct sock *sk;
2755 unsigned long count = 0;
2756
2757 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2758 if (sock_net(sk) != seq_file_net(seq))
2759 continue;
2760 if (++count == offset)
2761 break;
2762 }
2763
2764 return sk;
2765}
2766
2767static struct sock *unix_next_socket(struct seq_file *seq,
2768 struct sock *sk,
2769 loff_t *pos)
2770{
2771 unsigned long bucket;
2772
2773 while (sk > (struct sock *)SEQ_START_TOKEN) {
2774 sk = sk_next(sk);
2775 if (!sk)
2776 goto next_bucket;
2777 if (sock_net(sk) == seq_file_net(seq))
2778 return sk;
2779 }
2780
2781 do {
2782 sk = unix_from_bucket(seq, pos);
2783 if (sk)
2784 return sk;
2785
2786next_bucket:
2787 bucket = get_bucket(*pos) + 1;
2788 *pos = set_bucket_offset(bucket, 1);
2789 } while (bucket < ARRAY_SIZE(unix_socket_table));
2790
2791 return NULL;
2792}
2793
2794static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2795 __acquires(unix_table_lock)
2796{
2797 spin_lock(&unix_table_lock);
2798
2799 if (!*pos)
2800 return SEQ_START_TOKEN;
2801
2802 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2803 return NULL;
2804
2805 return unix_next_socket(seq, NULL, pos);
2806}
2807
2808static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2809{
2810 ++*pos;
2811 return unix_next_socket(seq, v, pos);
2812}
2813
2814static void unix_seq_stop(struct seq_file *seq, void *v)
2815 __releases(unix_table_lock)
2816{
2817 spin_unlock(&unix_table_lock);
2818}
2819
2820static int unix_seq_show(struct seq_file *seq, void *v)
2821{
2822
2823 if (v == SEQ_START_TOKEN)
2824 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2825 "Inode Path\n");
2826 else {
2827 struct sock *s = v;
2828 struct unix_sock *u = unix_sk(s);
2829 unix_state_lock(s);
2830
2831 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2832 s,
2833 refcount_read(&s->sk_refcnt),
2834 0,
2835 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2836 s->sk_type,
2837 s->sk_socket ?
2838 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2839 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2840 sock_i_ino(s));
2841
2842 if (u->addr) { // under unix_table_lock here
2843 int i, len;
2844 seq_putc(seq, ' ');
2845
2846 i = 0;
2847 len = u->addr->len - sizeof(short);
2848 if (!UNIX_ABSTRACT(s))
2849 len--;
2850 else {
2851 seq_putc(seq, '@');
2852 i++;
2853 }
2854 for ( ; i < len; i++)
2855 seq_putc(seq, u->addr->name->sun_path[i] ?:
2856 '@');
2857 }
2858 unix_state_unlock(s);
2859 seq_putc(seq, '\n');
2860 }
2861
2862 return 0;
2863}
2864
2865static const struct seq_operations unix_seq_ops = {
2866 .start = unix_seq_start,
2867 .next = unix_seq_next,
2868 .stop = unix_seq_stop,
2869 .show = unix_seq_show,
2870};
2871#endif
2872
2873static const struct net_proto_family unix_family_ops = {
2874 .family = PF_UNIX,
2875 .create = unix_create,
2876 .owner = THIS_MODULE,
2877};
2878
2879
2880static int __net_init unix_net_init(struct net *net)
2881{
2882 int error = -ENOMEM;
2883
2884 net->unx.sysctl_max_dgram_qlen = 10;
2885 if (unix_sysctl_register(net))
2886 goto out;
2887
2888#ifdef CONFIG_PROC_FS
2889 if (!proc_create_net("unix", 0, net->proc_net, &unix_seq_ops,
2890 sizeof(struct seq_net_private))) {
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) > sizeof_field(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);