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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 <linux/uaccess.h>
104#include <linux/skbuff.h>
105#include <linux/netdevice.h>
106#include <net/net_namespace.h>
107#include <net/sock.h>
108#include <net/tcp_states.h>
109#include <net/af_unix.h>
110#include <linux/proc_fs.h>
111#include <linux/seq_file.h>
112#include <net/scm.h>
113#include <linux/init.h>
114#include <linux/poll.h>
115#include <linux/rtnetlink.h>
116#include <linux/mount.h>
117#include <net/checksum.h>
118#include <linux/security.h>
119#include <linux/freezer.h>
120
121struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
122EXPORT_SYMBOL_GPL(unix_socket_table);
123DEFINE_SPINLOCK(unix_table_lock);
124EXPORT_SYMBOL_GPL(unix_table_lock);
125static atomic_long_t unix_nr_socks;
126
127
128static struct hlist_head *unix_sockets_unbound(void *addr)
129{
130 unsigned long hash = (unsigned long)addr;
131
132 hash ^= hash >> 16;
133 hash ^= hash >> 8;
134 hash %= UNIX_HASH_SIZE;
135 return &unix_socket_table[UNIX_HASH_SIZE + hash];
136}
137
138#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
139
140#ifdef CONFIG_SECURITY_NETWORK
141static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
142{
143 UNIXCB(skb).secid = scm->secid;
144}
145
146static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
147{
148 scm->secid = UNIXCB(skb).secid;
149}
150
151static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
152{
153 return (scm->secid == UNIXCB(skb).secid);
154}
155#else
156static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
157{ }
158
159static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
160{ }
161
162static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
163{
164 return true;
165}
166#endif /* CONFIG_SECURITY_NETWORK */
167
168/*
169 * SMP locking strategy:
170 * hash table is protected with spinlock unix_table_lock
171 * each socket state is protected by separate spin lock.
172 */
173
174static inline unsigned int unix_hash_fold(__wsum n)
175{
176 unsigned int hash = (__force unsigned int)csum_fold(n);
177
178 hash ^= hash>>8;
179 return hash&(UNIX_HASH_SIZE-1);
180}
181
182#define unix_peer(sk) (unix_sk(sk)->peer)
183
184static inline int unix_our_peer(struct sock *sk, struct sock *osk)
185{
186 return unix_peer(osk) == sk;
187}
188
189static inline int unix_may_send(struct sock *sk, struct sock *osk)
190{
191 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
192}
193
194static inline int unix_recvq_full(struct sock const *sk)
195{
196 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
197}
198
199struct sock *unix_peer_get(struct sock *s)
200{
201 struct sock *peer;
202
203 unix_state_lock(s);
204 peer = unix_peer(s);
205 if (peer)
206 sock_hold(peer);
207 unix_state_unlock(s);
208 return peer;
209}
210EXPORT_SYMBOL_GPL(unix_peer_get);
211
212static inline void unix_release_addr(struct unix_address *addr)
213{
214 if (atomic_dec_and_test(&addr->refcnt))
215 kfree(addr);
216}
217
218/*
219 * Check unix socket name:
220 * - should be not zero length.
221 * - if started by not zero, should be NULL terminated (FS object)
222 * - if started by zero, it is abstract name.
223 */
224
225static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
226{
227 if (len <= sizeof(short) || len > sizeof(*sunaddr))
228 return -EINVAL;
229 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
230 return -EINVAL;
231 if (sunaddr->sun_path[0]) {
232 /*
233 * This may look like an off by one error but it is a bit more
234 * subtle. 108 is the longest valid AF_UNIX path for a binding.
235 * sun_path[108] doesn't as such exist. However in kernel space
236 * we are guaranteed that it is a valid memory location in our
237 * kernel address buffer.
238 */
239 ((char *)sunaddr)[len] = 0;
240 len = strlen(sunaddr->sun_path)+1+sizeof(short);
241 return len;
242 }
243
244 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
245 return len;
246}
247
248static void __unix_remove_socket(struct sock *sk)
249{
250 sk_del_node_init(sk);
251}
252
253static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
254{
255 WARN_ON(!sk_unhashed(sk));
256 sk_add_node(sk, list);
257}
258
259static inline void unix_remove_socket(struct sock *sk)
260{
261 spin_lock(&unix_table_lock);
262 __unix_remove_socket(sk);
263 spin_unlock(&unix_table_lock);
264}
265
266static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
267{
268 spin_lock(&unix_table_lock);
269 __unix_insert_socket(list, sk);
270 spin_unlock(&unix_table_lock);
271}
272
273static struct sock *__unix_find_socket_byname(struct net *net,
274 struct sockaddr_un *sunname,
275 int len, int type, unsigned int hash)
276{
277 struct sock *s;
278
279 sk_for_each(s, &unix_socket_table[hash ^ type]) {
280 struct unix_sock *u = unix_sk(s);
281
282 if (!net_eq(sock_net(s), net))
283 continue;
284
285 if (u->addr->len == len &&
286 !memcmp(u->addr->name, sunname, len))
287 goto found;
288 }
289 s = NULL;
290found:
291 return s;
292}
293
294static inline struct sock *unix_find_socket_byname(struct net *net,
295 struct sockaddr_un *sunname,
296 int len, int type,
297 unsigned int hash)
298{
299 struct sock *s;
300
301 spin_lock(&unix_table_lock);
302 s = __unix_find_socket_byname(net, sunname, len, type, hash);
303 if (s)
304 sock_hold(s);
305 spin_unlock(&unix_table_lock);
306 return s;
307}
308
309static struct sock *unix_find_socket_byinode(struct inode *i)
310{
311 struct sock *s;
312
313 spin_lock(&unix_table_lock);
314 sk_for_each(s,
315 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
316 struct dentry *dentry = unix_sk(s)->path.dentry;
317
318 if (dentry && d_backing_inode(dentry) == i) {
319 sock_hold(s);
320 goto found;
321 }
322 }
323 s = NULL;
324found:
325 spin_unlock(&unix_table_lock);
326 return s;
327}
328
329/* Support code for asymmetrically connected dgram sockets
330 *
331 * If a datagram socket is connected to a socket not itself connected
332 * to the first socket (eg, /dev/log), clients may only enqueue more
333 * messages if the present receive queue of the server socket is not
334 * "too large". This means there's a second writeability condition
335 * poll and sendmsg need to test. The dgram recv code will do a wake
336 * up on the peer_wait wait queue of a socket upon reception of a
337 * datagram which needs to be propagated to sleeping would-be writers
338 * since these might not have sent anything so far. This can't be
339 * accomplished via poll_wait because the lifetime of the server
340 * socket might be less than that of its clients if these break their
341 * association with it or if the server socket is closed while clients
342 * are still connected to it and there's no way to inform "a polling
343 * implementation" that it should let go of a certain wait queue
344 *
345 * In order to propagate a wake up, a wait_queue_t of the client
346 * socket is enqueued on the peer_wait queue of the server socket
347 * whose wake function does a wake_up on the ordinary client socket
348 * wait queue. This connection is established whenever a write (or
349 * poll for write) hit the flow control condition and broken when the
350 * association to the server socket is dissolved or after a wake up
351 * was relayed.
352 */
353
354static int unix_dgram_peer_wake_relay(wait_queue_t *q, unsigned mode, int flags,
355 void *key)
356{
357 struct unix_sock *u;
358 wait_queue_head_t *u_sleep;
359
360 u = container_of(q, struct unix_sock, peer_wake);
361
362 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
363 q);
364 u->peer_wake.private = NULL;
365
366 /* relaying can only happen while the wq still exists */
367 u_sleep = sk_sleep(&u->sk);
368 if (u_sleep)
369 wake_up_interruptible_poll(u_sleep, key);
370
371 return 0;
372}
373
374static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
375{
376 struct unix_sock *u, *u_other;
377 int rc;
378
379 u = unix_sk(sk);
380 u_other = unix_sk(other);
381 rc = 0;
382 spin_lock(&u_other->peer_wait.lock);
383
384 if (!u->peer_wake.private) {
385 u->peer_wake.private = other;
386 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
387
388 rc = 1;
389 }
390
391 spin_unlock(&u_other->peer_wait.lock);
392 return rc;
393}
394
395static void unix_dgram_peer_wake_disconnect(struct sock *sk,
396 struct sock *other)
397{
398 struct unix_sock *u, *u_other;
399
400 u = unix_sk(sk);
401 u_other = unix_sk(other);
402 spin_lock(&u_other->peer_wait.lock);
403
404 if (u->peer_wake.private == other) {
405 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
406 u->peer_wake.private = NULL;
407 }
408
409 spin_unlock(&u_other->peer_wait.lock);
410}
411
412static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
413 struct sock *other)
414{
415 unix_dgram_peer_wake_disconnect(sk, other);
416 wake_up_interruptible_poll(sk_sleep(sk),
417 POLLOUT |
418 POLLWRNORM |
419 POLLWRBAND);
420}
421
422/* preconditions:
423 * - unix_peer(sk) == other
424 * - association is stable
425 */
426static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
427{
428 int connected;
429
430 connected = unix_dgram_peer_wake_connect(sk, other);
431
432 if (unix_recvq_full(other))
433 return 1;
434
435 if (connected)
436 unix_dgram_peer_wake_disconnect(sk, other);
437
438 return 0;
439}
440
441static int unix_writable(const struct sock *sk)
442{
443 return sk->sk_state != TCP_LISTEN &&
444 (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
445}
446
447static void unix_write_space(struct sock *sk)
448{
449 struct socket_wq *wq;
450
451 rcu_read_lock();
452 if (unix_writable(sk)) {
453 wq = rcu_dereference(sk->sk_wq);
454 if (skwq_has_sleeper(wq))
455 wake_up_interruptible_sync_poll(&wq->wait,
456 POLLOUT | POLLWRNORM | POLLWRBAND);
457 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
458 }
459 rcu_read_unlock();
460}
461
462/* When dgram socket disconnects (or changes its peer), we clear its receive
463 * queue of packets arrived from previous peer. First, it allows to do
464 * flow control based only on wmem_alloc; second, sk connected to peer
465 * may receive messages only from that peer. */
466static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
467{
468 if (!skb_queue_empty(&sk->sk_receive_queue)) {
469 skb_queue_purge(&sk->sk_receive_queue);
470 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
471
472 /* If one link of bidirectional dgram pipe is disconnected,
473 * we signal error. Messages are lost. Do not make this,
474 * when peer was not connected to us.
475 */
476 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
477 other->sk_err = ECONNRESET;
478 other->sk_error_report(other);
479 }
480 }
481}
482
483static void unix_sock_destructor(struct sock *sk)
484{
485 struct unix_sock *u = unix_sk(sk);
486
487 skb_queue_purge(&sk->sk_receive_queue);
488
489 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
490 WARN_ON(!sk_unhashed(sk));
491 WARN_ON(sk->sk_socket);
492 if (!sock_flag(sk, SOCK_DEAD)) {
493 pr_info("Attempt to release alive unix socket: %p\n", sk);
494 return;
495 }
496
497 if (u->addr)
498 unix_release_addr(u->addr);
499
500 atomic_long_dec(&unix_nr_socks);
501 local_bh_disable();
502 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
503 local_bh_enable();
504#ifdef UNIX_REFCNT_DEBUG
505 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
506 atomic_long_read(&unix_nr_socks));
507#endif
508}
509
510static void unix_release_sock(struct sock *sk, int embrion)
511{
512 struct unix_sock *u = unix_sk(sk);
513 struct path path;
514 struct sock *skpair;
515 struct sk_buff *skb;
516 int state;
517
518 unix_remove_socket(sk);
519
520 /* Clear state */
521 unix_state_lock(sk);
522 sock_orphan(sk);
523 sk->sk_shutdown = SHUTDOWN_MASK;
524 path = u->path;
525 u->path.dentry = NULL;
526 u->path.mnt = NULL;
527 state = sk->sk_state;
528 sk->sk_state = TCP_CLOSE;
529 unix_state_unlock(sk);
530
531 wake_up_interruptible_all(&u->peer_wait);
532
533 skpair = unix_peer(sk);
534
535 if (skpair != NULL) {
536 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
537 unix_state_lock(skpair);
538 /* No more writes */
539 skpair->sk_shutdown = SHUTDOWN_MASK;
540 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
541 skpair->sk_err = ECONNRESET;
542 unix_state_unlock(skpair);
543 skpair->sk_state_change(skpair);
544 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
545 }
546
547 unix_dgram_peer_wake_disconnect(sk, skpair);
548 sock_put(skpair); /* It may now die */
549 unix_peer(sk) = NULL;
550 }
551
552 /* Try to flush out this socket. Throw out buffers at least */
553
554 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
555 if (state == TCP_LISTEN)
556 unix_release_sock(skb->sk, 1);
557 /* passed fds are erased in the kfree_skb hook */
558 UNIXCB(skb).consumed = skb->len;
559 kfree_skb(skb);
560 }
561
562 if (path.dentry)
563 path_put(&path);
564
565 sock_put(sk);
566
567 /* ---- Socket is dead now and most probably destroyed ---- */
568
569 /*
570 * Fixme: BSD difference: In BSD all sockets connected to us get
571 * ECONNRESET and we die on the spot. In Linux we behave
572 * like files and pipes do and wait for the last
573 * dereference.
574 *
575 * Can't we simply set sock->err?
576 *
577 * What the above comment does talk about? --ANK(980817)
578 */
579
580 if (unix_tot_inflight)
581 unix_gc(); /* Garbage collect fds */
582}
583
584static void init_peercred(struct sock *sk)
585{
586 put_pid(sk->sk_peer_pid);
587 if (sk->sk_peer_cred)
588 put_cred(sk->sk_peer_cred);
589 sk->sk_peer_pid = get_pid(task_tgid(current));
590 sk->sk_peer_cred = get_current_cred();
591}
592
593static void copy_peercred(struct sock *sk, struct sock *peersk)
594{
595 put_pid(sk->sk_peer_pid);
596 if (sk->sk_peer_cred)
597 put_cred(sk->sk_peer_cred);
598 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
599 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
600}
601
602static int unix_listen(struct socket *sock, int backlog)
603{
604 int err;
605 struct sock *sk = sock->sk;
606 struct unix_sock *u = unix_sk(sk);
607 struct pid *old_pid = NULL;
608
609 err = -EOPNOTSUPP;
610 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
611 goto out; /* Only stream/seqpacket sockets accept */
612 err = -EINVAL;
613 if (!u->addr)
614 goto out; /* No listens on an unbound socket */
615 unix_state_lock(sk);
616 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
617 goto out_unlock;
618 if (backlog > sk->sk_max_ack_backlog)
619 wake_up_interruptible_all(&u->peer_wait);
620 sk->sk_max_ack_backlog = backlog;
621 sk->sk_state = TCP_LISTEN;
622 /* set credentials so connect can copy them */
623 init_peercred(sk);
624 err = 0;
625
626out_unlock:
627 unix_state_unlock(sk);
628 put_pid(old_pid);
629out:
630 return err;
631}
632
633static int unix_release(struct socket *);
634static int unix_bind(struct socket *, struct sockaddr *, int);
635static int unix_stream_connect(struct socket *, struct sockaddr *,
636 int addr_len, int flags);
637static int unix_socketpair(struct socket *, struct socket *);
638static int unix_accept(struct socket *, struct socket *, int);
639static int unix_getname(struct socket *, struct sockaddr *, int *, int);
640static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
641static unsigned int unix_dgram_poll(struct file *, struct socket *,
642 poll_table *);
643static int unix_ioctl(struct socket *, unsigned int, unsigned long);
644static int unix_shutdown(struct socket *, int);
645static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
646static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
647static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
648 size_t size, int flags);
649static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
650 struct pipe_inode_info *, size_t size,
651 unsigned int flags);
652static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
653static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
654static int unix_dgram_connect(struct socket *, struct sockaddr *,
655 int, int);
656static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
657static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
658 int);
659
660static int unix_set_peek_off(struct sock *sk, int val)
661{
662 struct unix_sock *u = unix_sk(sk);
663
664 if (mutex_lock_interruptible(&u->iolock))
665 return -EINTR;
666
667 sk->sk_peek_off = val;
668 mutex_unlock(&u->iolock);
669
670 return 0;
671}
672
673
674static const struct proto_ops unix_stream_ops = {
675 .family = PF_UNIX,
676 .owner = THIS_MODULE,
677 .release = unix_release,
678 .bind = unix_bind,
679 .connect = unix_stream_connect,
680 .socketpair = unix_socketpair,
681 .accept = unix_accept,
682 .getname = unix_getname,
683 .poll = unix_poll,
684 .ioctl = unix_ioctl,
685 .listen = unix_listen,
686 .shutdown = unix_shutdown,
687 .setsockopt = sock_no_setsockopt,
688 .getsockopt = sock_no_getsockopt,
689 .sendmsg = unix_stream_sendmsg,
690 .recvmsg = unix_stream_recvmsg,
691 .mmap = sock_no_mmap,
692 .sendpage = unix_stream_sendpage,
693 .splice_read = unix_stream_splice_read,
694 .set_peek_off = unix_set_peek_off,
695};
696
697static const struct proto_ops unix_dgram_ops = {
698 .family = PF_UNIX,
699 .owner = THIS_MODULE,
700 .release = unix_release,
701 .bind = unix_bind,
702 .connect = unix_dgram_connect,
703 .socketpair = unix_socketpair,
704 .accept = sock_no_accept,
705 .getname = unix_getname,
706 .poll = unix_dgram_poll,
707 .ioctl = unix_ioctl,
708 .listen = sock_no_listen,
709 .shutdown = unix_shutdown,
710 .setsockopt = sock_no_setsockopt,
711 .getsockopt = sock_no_getsockopt,
712 .sendmsg = unix_dgram_sendmsg,
713 .recvmsg = unix_dgram_recvmsg,
714 .mmap = sock_no_mmap,
715 .sendpage = sock_no_sendpage,
716 .set_peek_off = unix_set_peek_off,
717};
718
719static const struct proto_ops unix_seqpacket_ops = {
720 .family = PF_UNIX,
721 .owner = THIS_MODULE,
722 .release = unix_release,
723 .bind = unix_bind,
724 .connect = unix_stream_connect,
725 .socketpair = unix_socketpair,
726 .accept = unix_accept,
727 .getname = unix_getname,
728 .poll = unix_dgram_poll,
729 .ioctl = unix_ioctl,
730 .listen = unix_listen,
731 .shutdown = unix_shutdown,
732 .setsockopt = sock_no_setsockopt,
733 .getsockopt = sock_no_getsockopt,
734 .sendmsg = unix_seqpacket_sendmsg,
735 .recvmsg = unix_seqpacket_recvmsg,
736 .mmap = sock_no_mmap,
737 .sendpage = sock_no_sendpage,
738 .set_peek_off = unix_set_peek_off,
739};
740
741static struct proto unix_proto = {
742 .name = "UNIX",
743 .owner = THIS_MODULE,
744 .obj_size = sizeof(struct unix_sock),
745};
746
747/*
748 * AF_UNIX sockets do not interact with hardware, hence they
749 * dont trigger interrupts - so it's safe for them to have
750 * bh-unsafe locking for their sk_receive_queue.lock. Split off
751 * this special lock-class by reinitializing the spinlock key:
752 */
753static struct lock_class_key af_unix_sk_receive_queue_lock_key;
754
755static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
756{
757 struct sock *sk = NULL;
758 struct unix_sock *u;
759
760 atomic_long_inc(&unix_nr_socks);
761 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
762 goto out;
763
764 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
765 if (!sk)
766 goto out;
767
768 sock_init_data(sock, sk);
769 lockdep_set_class(&sk->sk_receive_queue.lock,
770 &af_unix_sk_receive_queue_lock_key);
771
772 sk->sk_allocation = GFP_KERNEL_ACCOUNT;
773 sk->sk_write_space = unix_write_space;
774 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
775 sk->sk_destruct = unix_sock_destructor;
776 u = unix_sk(sk);
777 u->path.dentry = NULL;
778 u->path.mnt = NULL;
779 spin_lock_init(&u->lock);
780 atomic_long_set(&u->inflight, 0);
781 INIT_LIST_HEAD(&u->link);
782 mutex_init(&u->iolock); /* single task reading lock */
783 mutex_init(&u->bindlock); /* single task binding lock */
784 init_waitqueue_head(&u->peer_wait);
785 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
786 unix_insert_socket(unix_sockets_unbound(sk), sk);
787out:
788 if (sk == NULL)
789 atomic_long_dec(&unix_nr_socks);
790 else {
791 local_bh_disable();
792 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
793 local_bh_enable();
794 }
795 return sk;
796}
797
798static int unix_create(struct net *net, struct socket *sock, int protocol,
799 int kern)
800{
801 if (protocol && protocol != PF_UNIX)
802 return -EPROTONOSUPPORT;
803
804 sock->state = SS_UNCONNECTED;
805
806 switch (sock->type) {
807 case SOCK_STREAM:
808 sock->ops = &unix_stream_ops;
809 break;
810 /*
811 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
812 * nothing uses it.
813 */
814 case SOCK_RAW:
815 sock->type = SOCK_DGRAM;
816 case SOCK_DGRAM:
817 sock->ops = &unix_dgram_ops;
818 break;
819 case SOCK_SEQPACKET:
820 sock->ops = &unix_seqpacket_ops;
821 break;
822 default:
823 return -ESOCKTNOSUPPORT;
824 }
825
826 return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
827}
828
829static int unix_release(struct socket *sock)
830{
831 struct sock *sk = sock->sk;
832
833 if (!sk)
834 return 0;
835
836 unix_release_sock(sk, 0);
837 sock->sk = NULL;
838
839 return 0;
840}
841
842static int unix_autobind(struct socket *sock)
843{
844 struct sock *sk = sock->sk;
845 struct net *net = sock_net(sk);
846 struct unix_sock *u = unix_sk(sk);
847 static u32 ordernum = 1;
848 struct unix_address *addr;
849 int err;
850 unsigned int retries = 0;
851
852 err = mutex_lock_interruptible(&u->bindlock);
853 if (err)
854 return err;
855
856 err = 0;
857 if (u->addr)
858 goto out;
859
860 err = -ENOMEM;
861 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
862 if (!addr)
863 goto out;
864
865 addr->name->sun_family = AF_UNIX;
866 atomic_set(&addr->refcnt, 1);
867
868retry:
869 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
870 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
871
872 spin_lock(&unix_table_lock);
873 ordernum = (ordernum+1)&0xFFFFF;
874
875 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
876 addr->hash)) {
877 spin_unlock(&unix_table_lock);
878 /*
879 * __unix_find_socket_byname() may take long time if many names
880 * are already in use.
881 */
882 cond_resched();
883 /* Give up if all names seems to be in use. */
884 if (retries++ == 0xFFFFF) {
885 err = -ENOSPC;
886 kfree(addr);
887 goto out;
888 }
889 goto retry;
890 }
891 addr->hash ^= sk->sk_type;
892
893 __unix_remove_socket(sk);
894 u->addr = addr;
895 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
896 spin_unlock(&unix_table_lock);
897 err = 0;
898
899out: mutex_unlock(&u->bindlock);
900 return err;
901}
902
903static struct sock *unix_find_other(struct net *net,
904 struct sockaddr_un *sunname, int len,
905 int type, unsigned int hash, int *error)
906{
907 struct sock *u;
908 struct path path;
909 int err = 0;
910
911 if (sunname->sun_path[0]) {
912 struct inode *inode;
913 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
914 if (err)
915 goto fail;
916 inode = d_backing_inode(path.dentry);
917 err = inode_permission(inode, MAY_WRITE);
918 if (err)
919 goto put_fail;
920
921 err = -ECONNREFUSED;
922 if (!S_ISSOCK(inode->i_mode))
923 goto put_fail;
924 u = unix_find_socket_byinode(inode);
925 if (!u)
926 goto put_fail;
927
928 if (u->sk_type == type)
929 touch_atime(&path);
930
931 path_put(&path);
932
933 err = -EPROTOTYPE;
934 if (u->sk_type != type) {
935 sock_put(u);
936 goto fail;
937 }
938 } else {
939 err = -ECONNREFUSED;
940 u = unix_find_socket_byname(net, sunname, len, type, hash);
941 if (u) {
942 struct dentry *dentry;
943 dentry = unix_sk(u)->path.dentry;
944 if (dentry)
945 touch_atime(&unix_sk(u)->path);
946 } else
947 goto fail;
948 }
949 return u;
950
951put_fail:
952 path_put(&path);
953fail:
954 *error = err;
955 return NULL;
956}
957
958static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
959{
960 struct dentry *dentry;
961 struct path path;
962 int err = 0;
963 /*
964 * Get the parent directory, calculate the hash for last
965 * component.
966 */
967 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
968 err = PTR_ERR(dentry);
969 if (IS_ERR(dentry))
970 return err;
971
972 /*
973 * All right, let's create it.
974 */
975 err = security_path_mknod(&path, dentry, mode, 0);
976 if (!err) {
977 err = vfs_mknod(d_inode(path.dentry), dentry, mode, 0);
978 if (!err) {
979 res->mnt = mntget(path.mnt);
980 res->dentry = dget(dentry);
981 }
982 }
983 done_path_create(&path, dentry);
984 return err;
985}
986
987static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
988{
989 struct sock *sk = sock->sk;
990 struct net *net = sock_net(sk);
991 struct unix_sock *u = unix_sk(sk);
992 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
993 char *sun_path = sunaddr->sun_path;
994 int err;
995 unsigned int hash;
996 struct unix_address *addr;
997 struct hlist_head *list;
998 struct path path = { NULL, NULL };
999
1000 err = -EINVAL;
1001 if (sunaddr->sun_family != AF_UNIX)
1002 goto out;
1003
1004 if (addr_len == sizeof(short)) {
1005 err = unix_autobind(sock);
1006 goto out;
1007 }
1008
1009 err = unix_mkname(sunaddr, addr_len, &hash);
1010 if (err < 0)
1011 goto out;
1012 addr_len = err;
1013
1014 if (sun_path[0]) {
1015 umode_t mode = S_IFSOCK |
1016 (SOCK_INODE(sock)->i_mode & ~current_umask());
1017 err = unix_mknod(sun_path, mode, &path);
1018 if (err) {
1019 if (err == -EEXIST)
1020 err = -EADDRINUSE;
1021 goto out;
1022 }
1023 }
1024
1025 err = mutex_lock_interruptible(&u->bindlock);
1026 if (err)
1027 goto out_put;
1028
1029 err = -EINVAL;
1030 if (u->addr)
1031 goto out_up;
1032
1033 err = -ENOMEM;
1034 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
1035 if (!addr)
1036 goto out_up;
1037
1038 memcpy(addr->name, sunaddr, addr_len);
1039 addr->len = addr_len;
1040 addr->hash = hash ^ sk->sk_type;
1041 atomic_set(&addr->refcnt, 1);
1042
1043 if (sun_path[0]) {
1044 addr->hash = UNIX_HASH_SIZE;
1045 hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE - 1);
1046 spin_lock(&unix_table_lock);
1047 u->path = path;
1048 list = &unix_socket_table[hash];
1049 } else {
1050 spin_lock(&unix_table_lock);
1051 err = -EADDRINUSE;
1052 if (__unix_find_socket_byname(net, sunaddr, addr_len,
1053 sk->sk_type, hash)) {
1054 unix_release_addr(addr);
1055 goto out_unlock;
1056 }
1057
1058 list = &unix_socket_table[addr->hash];
1059 }
1060
1061 err = 0;
1062 __unix_remove_socket(sk);
1063 u->addr = addr;
1064 __unix_insert_socket(list, sk);
1065
1066out_unlock:
1067 spin_unlock(&unix_table_lock);
1068out_up:
1069 mutex_unlock(&u->bindlock);
1070out_put:
1071 if (err)
1072 path_put(&path);
1073out:
1074 return err;
1075}
1076
1077static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1078{
1079 if (unlikely(sk1 == sk2) || !sk2) {
1080 unix_state_lock(sk1);
1081 return;
1082 }
1083 if (sk1 < sk2) {
1084 unix_state_lock(sk1);
1085 unix_state_lock_nested(sk2);
1086 } else {
1087 unix_state_lock(sk2);
1088 unix_state_lock_nested(sk1);
1089 }
1090}
1091
1092static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1093{
1094 if (unlikely(sk1 == sk2) || !sk2) {
1095 unix_state_unlock(sk1);
1096 return;
1097 }
1098 unix_state_unlock(sk1);
1099 unix_state_unlock(sk2);
1100}
1101
1102static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1103 int alen, int flags)
1104{
1105 struct sock *sk = sock->sk;
1106 struct net *net = sock_net(sk);
1107 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1108 struct sock *other;
1109 unsigned int hash;
1110 int err;
1111
1112 if (addr->sa_family != AF_UNSPEC) {
1113 err = unix_mkname(sunaddr, alen, &hash);
1114 if (err < 0)
1115 goto out;
1116 alen = err;
1117
1118 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1119 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1120 goto out;
1121
1122restart:
1123 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1124 if (!other)
1125 goto out;
1126
1127 unix_state_double_lock(sk, other);
1128
1129 /* Apparently VFS overslept socket death. Retry. */
1130 if (sock_flag(other, SOCK_DEAD)) {
1131 unix_state_double_unlock(sk, other);
1132 sock_put(other);
1133 goto restart;
1134 }
1135
1136 err = -EPERM;
1137 if (!unix_may_send(sk, other))
1138 goto out_unlock;
1139
1140 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1141 if (err)
1142 goto out_unlock;
1143
1144 } else {
1145 /*
1146 * 1003.1g breaking connected state with AF_UNSPEC
1147 */
1148 other = NULL;
1149 unix_state_double_lock(sk, other);
1150 }
1151
1152 /*
1153 * If it was connected, reconnect.
1154 */
1155 if (unix_peer(sk)) {
1156 struct sock *old_peer = unix_peer(sk);
1157 unix_peer(sk) = other;
1158 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1159
1160 unix_state_double_unlock(sk, other);
1161
1162 if (other != old_peer)
1163 unix_dgram_disconnected(sk, old_peer);
1164 sock_put(old_peer);
1165 } else {
1166 unix_peer(sk) = other;
1167 unix_state_double_unlock(sk, other);
1168 }
1169 return 0;
1170
1171out_unlock:
1172 unix_state_double_unlock(sk, other);
1173 sock_put(other);
1174out:
1175 return err;
1176}
1177
1178static long unix_wait_for_peer(struct sock *other, long timeo)
1179{
1180 struct unix_sock *u = unix_sk(other);
1181 int sched;
1182 DEFINE_WAIT(wait);
1183
1184 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1185
1186 sched = !sock_flag(other, SOCK_DEAD) &&
1187 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1188 unix_recvq_full(other);
1189
1190 unix_state_unlock(other);
1191
1192 if (sched)
1193 timeo = schedule_timeout(timeo);
1194
1195 finish_wait(&u->peer_wait, &wait);
1196 return timeo;
1197}
1198
1199static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1200 int addr_len, int flags)
1201{
1202 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1203 struct sock *sk = sock->sk;
1204 struct net *net = sock_net(sk);
1205 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1206 struct sock *newsk = NULL;
1207 struct sock *other = NULL;
1208 struct sk_buff *skb = NULL;
1209 unsigned int hash;
1210 int st;
1211 int err;
1212 long timeo;
1213
1214 err = unix_mkname(sunaddr, addr_len, &hash);
1215 if (err < 0)
1216 goto out;
1217 addr_len = err;
1218
1219 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1220 (err = unix_autobind(sock)) != 0)
1221 goto out;
1222
1223 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1224
1225 /* First of all allocate resources.
1226 If we will make it after state is locked,
1227 we will have to recheck all again in any case.
1228 */
1229
1230 err = -ENOMEM;
1231
1232 /* create new sock for complete connection */
1233 newsk = unix_create1(sock_net(sk), NULL, 0);
1234 if (newsk == NULL)
1235 goto out;
1236
1237 /* Allocate skb for sending to listening sock */
1238 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1239 if (skb == NULL)
1240 goto out;
1241
1242restart:
1243 /* Find listening sock. */
1244 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1245 if (!other)
1246 goto out;
1247
1248 /* Latch state of peer */
1249 unix_state_lock(other);
1250
1251 /* Apparently VFS overslept socket death. Retry. */
1252 if (sock_flag(other, SOCK_DEAD)) {
1253 unix_state_unlock(other);
1254 sock_put(other);
1255 goto restart;
1256 }
1257
1258 err = -ECONNREFUSED;
1259 if (other->sk_state != TCP_LISTEN)
1260 goto out_unlock;
1261 if (other->sk_shutdown & RCV_SHUTDOWN)
1262 goto out_unlock;
1263
1264 if (unix_recvq_full(other)) {
1265 err = -EAGAIN;
1266 if (!timeo)
1267 goto out_unlock;
1268
1269 timeo = unix_wait_for_peer(other, timeo);
1270
1271 err = sock_intr_errno(timeo);
1272 if (signal_pending(current))
1273 goto out;
1274 sock_put(other);
1275 goto restart;
1276 }
1277
1278 /* Latch our state.
1279
1280 It is tricky place. We need to grab our state lock and cannot
1281 drop lock on peer. It is dangerous because deadlock is
1282 possible. Connect to self case and simultaneous
1283 attempt to connect are eliminated by checking socket
1284 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1285 check this before attempt to grab lock.
1286
1287 Well, and we have to recheck the state after socket locked.
1288 */
1289 st = sk->sk_state;
1290
1291 switch (st) {
1292 case TCP_CLOSE:
1293 /* This is ok... continue with connect */
1294 break;
1295 case TCP_ESTABLISHED:
1296 /* Socket is already connected */
1297 err = -EISCONN;
1298 goto out_unlock;
1299 default:
1300 err = -EINVAL;
1301 goto out_unlock;
1302 }
1303
1304 unix_state_lock_nested(sk);
1305
1306 if (sk->sk_state != st) {
1307 unix_state_unlock(sk);
1308 unix_state_unlock(other);
1309 sock_put(other);
1310 goto restart;
1311 }
1312
1313 err = security_unix_stream_connect(sk, other, newsk);
1314 if (err) {
1315 unix_state_unlock(sk);
1316 goto out_unlock;
1317 }
1318
1319 /* The way is open! Fastly set all the necessary fields... */
1320
1321 sock_hold(sk);
1322 unix_peer(newsk) = sk;
1323 newsk->sk_state = TCP_ESTABLISHED;
1324 newsk->sk_type = sk->sk_type;
1325 init_peercred(newsk);
1326 newu = unix_sk(newsk);
1327 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1328 otheru = unix_sk(other);
1329
1330 /* copy address information from listening to new sock*/
1331 if (otheru->addr) {
1332 atomic_inc(&otheru->addr->refcnt);
1333 newu->addr = otheru->addr;
1334 }
1335 if (otheru->path.dentry) {
1336 path_get(&otheru->path);
1337 newu->path = otheru->path;
1338 }
1339
1340 /* Set credentials */
1341 copy_peercred(sk, other);
1342
1343 sock->state = SS_CONNECTED;
1344 sk->sk_state = TCP_ESTABLISHED;
1345 sock_hold(newsk);
1346
1347 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1348 unix_peer(sk) = newsk;
1349
1350 unix_state_unlock(sk);
1351
1352 /* take ten and and send info to listening sock */
1353 spin_lock(&other->sk_receive_queue.lock);
1354 __skb_queue_tail(&other->sk_receive_queue, skb);
1355 spin_unlock(&other->sk_receive_queue.lock);
1356 unix_state_unlock(other);
1357 other->sk_data_ready(other);
1358 sock_put(other);
1359 return 0;
1360
1361out_unlock:
1362 if (other)
1363 unix_state_unlock(other);
1364
1365out:
1366 kfree_skb(skb);
1367 if (newsk)
1368 unix_release_sock(newsk, 0);
1369 if (other)
1370 sock_put(other);
1371 return err;
1372}
1373
1374static int unix_socketpair(struct socket *socka, struct socket *sockb)
1375{
1376 struct sock *ska = socka->sk, *skb = sockb->sk;
1377
1378 /* Join our sockets back to back */
1379 sock_hold(ska);
1380 sock_hold(skb);
1381 unix_peer(ska) = skb;
1382 unix_peer(skb) = ska;
1383 init_peercred(ska);
1384 init_peercred(skb);
1385
1386 if (ska->sk_type != SOCK_DGRAM) {
1387 ska->sk_state = TCP_ESTABLISHED;
1388 skb->sk_state = TCP_ESTABLISHED;
1389 socka->state = SS_CONNECTED;
1390 sockb->state = SS_CONNECTED;
1391 }
1392 return 0;
1393}
1394
1395static void unix_sock_inherit_flags(const struct socket *old,
1396 struct socket *new)
1397{
1398 if (test_bit(SOCK_PASSCRED, &old->flags))
1399 set_bit(SOCK_PASSCRED, &new->flags);
1400 if (test_bit(SOCK_PASSSEC, &old->flags))
1401 set_bit(SOCK_PASSSEC, &new->flags);
1402}
1403
1404static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1405{
1406 struct sock *sk = sock->sk;
1407 struct sock *tsk;
1408 struct sk_buff *skb;
1409 int err;
1410
1411 err = -EOPNOTSUPP;
1412 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1413 goto out;
1414
1415 err = -EINVAL;
1416 if (sk->sk_state != TCP_LISTEN)
1417 goto out;
1418
1419 /* If socket state is TCP_LISTEN it cannot change (for now...),
1420 * so that no locks are necessary.
1421 */
1422
1423 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1424 if (!skb) {
1425 /* This means receive shutdown. */
1426 if (err == 0)
1427 err = -EINVAL;
1428 goto out;
1429 }
1430
1431 tsk = skb->sk;
1432 skb_free_datagram(sk, skb);
1433 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1434
1435 /* attach accepted sock to socket */
1436 unix_state_lock(tsk);
1437 newsock->state = SS_CONNECTED;
1438 unix_sock_inherit_flags(sock, newsock);
1439 sock_graft(tsk, newsock);
1440 unix_state_unlock(tsk);
1441 return 0;
1442
1443out:
1444 return err;
1445}
1446
1447
1448static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1449{
1450 struct sock *sk = sock->sk;
1451 struct unix_sock *u;
1452 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1453 int err = 0;
1454
1455 if (peer) {
1456 sk = unix_peer_get(sk);
1457
1458 err = -ENOTCONN;
1459 if (!sk)
1460 goto out;
1461 err = 0;
1462 } else {
1463 sock_hold(sk);
1464 }
1465
1466 u = unix_sk(sk);
1467 unix_state_lock(sk);
1468 if (!u->addr) {
1469 sunaddr->sun_family = AF_UNIX;
1470 sunaddr->sun_path[0] = 0;
1471 *uaddr_len = sizeof(short);
1472 } else {
1473 struct unix_address *addr = u->addr;
1474
1475 *uaddr_len = addr->len;
1476 memcpy(sunaddr, addr->name, *uaddr_len);
1477 }
1478 unix_state_unlock(sk);
1479 sock_put(sk);
1480out:
1481 return err;
1482}
1483
1484static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1485{
1486 int i;
1487
1488 scm->fp = UNIXCB(skb).fp;
1489 UNIXCB(skb).fp = NULL;
1490
1491 for (i = scm->fp->count-1; i >= 0; i--)
1492 unix_notinflight(scm->fp->user, scm->fp->fp[i]);
1493}
1494
1495static void unix_destruct_scm(struct sk_buff *skb)
1496{
1497 struct scm_cookie scm;
1498 memset(&scm, 0, sizeof(scm));
1499 scm.pid = UNIXCB(skb).pid;
1500 if (UNIXCB(skb).fp)
1501 unix_detach_fds(&scm, skb);
1502
1503 /* Alas, it calls VFS */
1504 /* So fscking what? fput() had been SMP-safe since the last Summer */
1505 scm_destroy(&scm);
1506 sock_wfree(skb);
1507}
1508
1509/*
1510 * The "user->unix_inflight" variable is protected by the garbage
1511 * collection lock, and we just read it locklessly here. If you go
1512 * over the limit, there might be a tiny race in actually noticing
1513 * it across threads. Tough.
1514 */
1515static inline bool too_many_unix_fds(struct task_struct *p)
1516{
1517 struct user_struct *user = current_user();
1518
1519 if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
1520 return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1521 return false;
1522}
1523
1524#define MAX_RECURSION_LEVEL 4
1525
1526static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1527{
1528 int i;
1529 unsigned char max_level = 0;
1530
1531 if (too_many_unix_fds(current))
1532 return -ETOOMANYREFS;
1533
1534 for (i = scm->fp->count - 1; i >= 0; i--) {
1535 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1536
1537 if (sk)
1538 max_level = max(max_level,
1539 unix_sk(sk)->recursion_level);
1540 }
1541 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1542 return -ETOOMANYREFS;
1543
1544 /*
1545 * Need to duplicate file references for the sake of garbage
1546 * collection. Otherwise a socket in the fps might become a
1547 * candidate for GC while the skb is not yet queued.
1548 */
1549 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1550 if (!UNIXCB(skb).fp)
1551 return -ENOMEM;
1552
1553 for (i = scm->fp->count - 1; i >= 0; i--)
1554 unix_inflight(scm->fp->user, scm->fp->fp[i]);
1555 return max_level;
1556}
1557
1558static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1559{
1560 int err = 0;
1561
1562 UNIXCB(skb).pid = get_pid(scm->pid);
1563 UNIXCB(skb).uid = scm->creds.uid;
1564 UNIXCB(skb).gid = scm->creds.gid;
1565 UNIXCB(skb).fp = NULL;
1566 unix_get_secdata(scm, skb);
1567 if (scm->fp && send_fds)
1568 err = unix_attach_fds(scm, skb);
1569
1570 skb->destructor = unix_destruct_scm;
1571 return err;
1572}
1573
1574static bool unix_passcred_enabled(const struct socket *sock,
1575 const struct sock *other)
1576{
1577 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1578 !other->sk_socket ||
1579 test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1580}
1581
1582/*
1583 * Some apps rely on write() giving SCM_CREDENTIALS
1584 * We include credentials if source or destination socket
1585 * asserted SOCK_PASSCRED.
1586 */
1587static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1588 const struct sock *other)
1589{
1590 if (UNIXCB(skb).pid)
1591 return;
1592 if (unix_passcred_enabled(sock, other)) {
1593 UNIXCB(skb).pid = get_pid(task_tgid(current));
1594 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1595 }
1596}
1597
1598static int maybe_init_creds(struct scm_cookie *scm,
1599 struct socket *socket,
1600 const struct sock *other)
1601{
1602 int err;
1603 struct msghdr msg = { .msg_controllen = 0 };
1604
1605 err = scm_send(socket, &msg, scm, false);
1606 if (err)
1607 return err;
1608
1609 if (unix_passcred_enabled(socket, other)) {
1610 scm->pid = get_pid(task_tgid(current));
1611 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1612 }
1613 return err;
1614}
1615
1616static bool unix_skb_scm_eq(struct sk_buff *skb,
1617 struct scm_cookie *scm)
1618{
1619 const struct unix_skb_parms *u = &UNIXCB(skb);
1620
1621 return u->pid == scm->pid &&
1622 uid_eq(u->uid, scm->creds.uid) &&
1623 gid_eq(u->gid, scm->creds.gid) &&
1624 unix_secdata_eq(scm, skb);
1625}
1626
1627/*
1628 * Send AF_UNIX data.
1629 */
1630
1631static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1632 size_t len)
1633{
1634 struct sock *sk = sock->sk;
1635 struct net *net = sock_net(sk);
1636 struct unix_sock *u = unix_sk(sk);
1637 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1638 struct sock *other = NULL;
1639 int namelen = 0; /* fake GCC */
1640 int err;
1641 unsigned int hash;
1642 struct sk_buff *skb;
1643 long timeo;
1644 struct scm_cookie scm;
1645 int max_level;
1646 int data_len = 0;
1647 int sk_locked;
1648
1649 wait_for_unix_gc();
1650 err = scm_send(sock, msg, &scm, false);
1651 if (err < 0)
1652 return err;
1653
1654 err = -EOPNOTSUPP;
1655 if (msg->msg_flags&MSG_OOB)
1656 goto out;
1657
1658 if (msg->msg_namelen) {
1659 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1660 if (err < 0)
1661 goto out;
1662 namelen = err;
1663 } else {
1664 sunaddr = NULL;
1665 err = -ENOTCONN;
1666 other = unix_peer_get(sk);
1667 if (!other)
1668 goto out;
1669 }
1670
1671 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1672 && (err = unix_autobind(sock)) != 0)
1673 goto out;
1674
1675 err = -EMSGSIZE;
1676 if (len > sk->sk_sndbuf - 32)
1677 goto out;
1678
1679 if (len > SKB_MAX_ALLOC) {
1680 data_len = min_t(size_t,
1681 len - SKB_MAX_ALLOC,
1682 MAX_SKB_FRAGS * PAGE_SIZE);
1683 data_len = PAGE_ALIGN(data_len);
1684
1685 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1686 }
1687
1688 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1689 msg->msg_flags & MSG_DONTWAIT, &err,
1690 PAGE_ALLOC_COSTLY_ORDER);
1691 if (skb == NULL)
1692 goto out;
1693
1694 err = unix_scm_to_skb(&scm, skb, true);
1695 if (err < 0)
1696 goto out_free;
1697 max_level = err + 1;
1698
1699 skb_put(skb, len - data_len);
1700 skb->data_len = data_len;
1701 skb->len = len;
1702 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1703 if (err)
1704 goto out_free;
1705
1706 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1707
1708restart:
1709 if (!other) {
1710 err = -ECONNRESET;
1711 if (sunaddr == NULL)
1712 goto out_free;
1713
1714 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1715 hash, &err);
1716 if (other == NULL)
1717 goto out_free;
1718 }
1719
1720 if (sk_filter(other, skb) < 0) {
1721 /* Toss the packet but do not return any error to the sender */
1722 err = len;
1723 goto out_free;
1724 }
1725
1726 sk_locked = 0;
1727 unix_state_lock(other);
1728restart_locked:
1729 err = -EPERM;
1730 if (!unix_may_send(sk, other))
1731 goto out_unlock;
1732
1733 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1734 /*
1735 * Check with 1003.1g - what should
1736 * datagram error
1737 */
1738 unix_state_unlock(other);
1739 sock_put(other);
1740
1741 if (!sk_locked)
1742 unix_state_lock(sk);
1743
1744 err = 0;
1745 if (unix_peer(sk) == other) {
1746 unix_peer(sk) = NULL;
1747 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1748
1749 unix_state_unlock(sk);
1750
1751 unix_dgram_disconnected(sk, other);
1752 sock_put(other);
1753 err = -ECONNREFUSED;
1754 } else {
1755 unix_state_unlock(sk);
1756 }
1757
1758 other = NULL;
1759 if (err)
1760 goto out_free;
1761 goto restart;
1762 }
1763
1764 err = -EPIPE;
1765 if (other->sk_shutdown & RCV_SHUTDOWN)
1766 goto out_unlock;
1767
1768 if (sk->sk_type != SOCK_SEQPACKET) {
1769 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1770 if (err)
1771 goto out_unlock;
1772 }
1773
1774 /* other == sk && unix_peer(other) != sk if
1775 * - unix_peer(sk) == NULL, destination address bound to sk
1776 * - unix_peer(sk) == sk by time of get but disconnected before lock
1777 */
1778 if (other != sk &&
1779 unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1780 if (timeo) {
1781 timeo = unix_wait_for_peer(other, timeo);
1782
1783 err = sock_intr_errno(timeo);
1784 if (signal_pending(current))
1785 goto out_free;
1786
1787 goto restart;
1788 }
1789
1790 if (!sk_locked) {
1791 unix_state_unlock(other);
1792 unix_state_double_lock(sk, other);
1793 }
1794
1795 if (unix_peer(sk) != other ||
1796 unix_dgram_peer_wake_me(sk, other)) {
1797 err = -EAGAIN;
1798 sk_locked = 1;
1799 goto out_unlock;
1800 }
1801
1802 if (!sk_locked) {
1803 sk_locked = 1;
1804 goto restart_locked;
1805 }
1806 }
1807
1808 if (unlikely(sk_locked))
1809 unix_state_unlock(sk);
1810
1811 if (sock_flag(other, SOCK_RCVTSTAMP))
1812 __net_timestamp(skb);
1813 maybe_add_creds(skb, sock, other);
1814 skb_queue_tail(&other->sk_receive_queue, skb);
1815 if (max_level > unix_sk(other)->recursion_level)
1816 unix_sk(other)->recursion_level = max_level;
1817 unix_state_unlock(other);
1818 other->sk_data_ready(other);
1819 sock_put(other);
1820 scm_destroy(&scm);
1821 return len;
1822
1823out_unlock:
1824 if (sk_locked)
1825 unix_state_unlock(sk);
1826 unix_state_unlock(other);
1827out_free:
1828 kfree_skb(skb);
1829out:
1830 if (other)
1831 sock_put(other);
1832 scm_destroy(&scm);
1833 return err;
1834}
1835
1836/* We use paged skbs for stream sockets, and limit occupancy to 32768
1837 * bytes, and a minimun of a full page.
1838 */
1839#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1840
1841static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
1842 size_t len)
1843{
1844 struct sock *sk = sock->sk;
1845 struct sock *other = NULL;
1846 int err, size;
1847 struct sk_buff *skb;
1848 int sent = 0;
1849 struct scm_cookie scm;
1850 bool fds_sent = false;
1851 int max_level;
1852 int data_len;
1853
1854 wait_for_unix_gc();
1855 err = scm_send(sock, msg, &scm, false);
1856 if (err < 0)
1857 return err;
1858
1859 err = -EOPNOTSUPP;
1860 if (msg->msg_flags&MSG_OOB)
1861 goto out_err;
1862
1863 if (msg->msg_namelen) {
1864 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1865 goto out_err;
1866 } else {
1867 err = -ENOTCONN;
1868 other = unix_peer(sk);
1869 if (!other)
1870 goto out_err;
1871 }
1872
1873 if (sk->sk_shutdown & SEND_SHUTDOWN)
1874 goto pipe_err;
1875
1876 while (sent < len) {
1877 size = len - sent;
1878
1879 /* Keep two messages in the pipe so it schedules better */
1880 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1881
1882 /* allow fallback to order-0 allocations */
1883 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1884
1885 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1886
1887 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
1888
1889 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1890 msg->msg_flags & MSG_DONTWAIT, &err,
1891 get_order(UNIX_SKB_FRAGS_SZ));
1892 if (!skb)
1893 goto out_err;
1894
1895 /* Only send the fds in the first buffer */
1896 err = unix_scm_to_skb(&scm, skb, !fds_sent);
1897 if (err < 0) {
1898 kfree_skb(skb);
1899 goto out_err;
1900 }
1901 max_level = err + 1;
1902 fds_sent = true;
1903
1904 skb_put(skb, size - data_len);
1905 skb->data_len = data_len;
1906 skb->len = size;
1907 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
1908 if (err) {
1909 kfree_skb(skb);
1910 goto out_err;
1911 }
1912
1913 unix_state_lock(other);
1914
1915 if (sock_flag(other, SOCK_DEAD) ||
1916 (other->sk_shutdown & RCV_SHUTDOWN))
1917 goto pipe_err_free;
1918
1919 maybe_add_creds(skb, sock, other);
1920 skb_queue_tail(&other->sk_receive_queue, skb);
1921 if (max_level > unix_sk(other)->recursion_level)
1922 unix_sk(other)->recursion_level = max_level;
1923 unix_state_unlock(other);
1924 other->sk_data_ready(other);
1925 sent += size;
1926 }
1927
1928 scm_destroy(&scm);
1929
1930 return sent;
1931
1932pipe_err_free:
1933 unix_state_unlock(other);
1934 kfree_skb(skb);
1935pipe_err:
1936 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1937 send_sig(SIGPIPE, current, 0);
1938 err = -EPIPE;
1939out_err:
1940 scm_destroy(&scm);
1941 return sent ? : err;
1942}
1943
1944static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
1945 int offset, size_t size, int flags)
1946{
1947 int err;
1948 bool send_sigpipe = false;
1949 bool init_scm = true;
1950 struct scm_cookie scm;
1951 struct sock *other, *sk = socket->sk;
1952 struct sk_buff *skb, *newskb = NULL, *tail = NULL;
1953
1954 if (flags & MSG_OOB)
1955 return -EOPNOTSUPP;
1956
1957 other = unix_peer(sk);
1958 if (!other || sk->sk_state != TCP_ESTABLISHED)
1959 return -ENOTCONN;
1960
1961 if (false) {
1962alloc_skb:
1963 unix_state_unlock(other);
1964 mutex_unlock(&unix_sk(other)->iolock);
1965 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
1966 &err, 0);
1967 if (!newskb)
1968 goto err;
1969 }
1970
1971 /* we must acquire iolock as we modify already present
1972 * skbs in the sk_receive_queue and mess with skb->len
1973 */
1974 err = mutex_lock_interruptible(&unix_sk(other)->iolock);
1975 if (err) {
1976 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
1977 goto err;
1978 }
1979
1980 if (sk->sk_shutdown & SEND_SHUTDOWN) {
1981 err = -EPIPE;
1982 send_sigpipe = true;
1983 goto err_unlock;
1984 }
1985
1986 unix_state_lock(other);
1987
1988 if (sock_flag(other, SOCK_DEAD) ||
1989 other->sk_shutdown & RCV_SHUTDOWN) {
1990 err = -EPIPE;
1991 send_sigpipe = true;
1992 goto err_state_unlock;
1993 }
1994
1995 if (init_scm) {
1996 err = maybe_init_creds(&scm, socket, other);
1997 if (err)
1998 goto err_state_unlock;
1999 init_scm = false;
2000 }
2001
2002 skb = skb_peek_tail(&other->sk_receive_queue);
2003 if (tail && tail == skb) {
2004 skb = newskb;
2005 } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
2006 if (newskb) {
2007 skb = newskb;
2008 } else {
2009 tail = skb;
2010 goto alloc_skb;
2011 }
2012 } else if (newskb) {
2013 /* this is fast path, we don't necessarily need to
2014 * call to kfree_skb even though with newskb == NULL
2015 * this - does no harm
2016 */
2017 consume_skb(newskb);
2018 newskb = NULL;
2019 }
2020
2021 if (skb_append_pagefrags(skb, page, offset, size)) {
2022 tail = skb;
2023 goto alloc_skb;
2024 }
2025
2026 skb->len += size;
2027 skb->data_len += size;
2028 skb->truesize += size;
2029 atomic_add(size, &sk->sk_wmem_alloc);
2030
2031 if (newskb) {
2032 err = unix_scm_to_skb(&scm, skb, false);
2033 if (err)
2034 goto err_state_unlock;
2035 spin_lock(&other->sk_receive_queue.lock);
2036 __skb_queue_tail(&other->sk_receive_queue, newskb);
2037 spin_unlock(&other->sk_receive_queue.lock);
2038 }
2039
2040 unix_state_unlock(other);
2041 mutex_unlock(&unix_sk(other)->iolock);
2042
2043 other->sk_data_ready(other);
2044 scm_destroy(&scm);
2045 return size;
2046
2047err_state_unlock:
2048 unix_state_unlock(other);
2049err_unlock:
2050 mutex_unlock(&unix_sk(other)->iolock);
2051err:
2052 kfree_skb(newskb);
2053 if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2054 send_sig(SIGPIPE, current, 0);
2055 if (!init_scm)
2056 scm_destroy(&scm);
2057 return err;
2058}
2059
2060static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2061 size_t len)
2062{
2063 int err;
2064 struct sock *sk = sock->sk;
2065
2066 err = sock_error(sk);
2067 if (err)
2068 return err;
2069
2070 if (sk->sk_state != TCP_ESTABLISHED)
2071 return -ENOTCONN;
2072
2073 if (msg->msg_namelen)
2074 msg->msg_namelen = 0;
2075
2076 return unix_dgram_sendmsg(sock, msg, len);
2077}
2078
2079static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2080 size_t size, int flags)
2081{
2082 struct sock *sk = sock->sk;
2083
2084 if (sk->sk_state != TCP_ESTABLISHED)
2085 return -ENOTCONN;
2086
2087 return unix_dgram_recvmsg(sock, msg, size, flags);
2088}
2089
2090static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2091{
2092 struct unix_sock *u = unix_sk(sk);
2093
2094 if (u->addr) {
2095 msg->msg_namelen = u->addr->len;
2096 memcpy(msg->msg_name, u->addr->name, u->addr->len);
2097 }
2098}
2099
2100static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
2101 size_t size, int flags)
2102{
2103 struct scm_cookie scm;
2104 struct sock *sk = sock->sk;
2105 struct unix_sock *u = unix_sk(sk);
2106 struct sk_buff *skb, *last;
2107 long timeo;
2108 int err;
2109 int peeked, skip;
2110
2111 err = -EOPNOTSUPP;
2112 if (flags&MSG_OOB)
2113 goto out;
2114
2115 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2116
2117 do {
2118 mutex_lock(&u->iolock);
2119
2120 skip = sk_peek_offset(sk, flags);
2121 skb = __skb_try_recv_datagram(sk, flags, NULL, &peeked, &skip,
2122 &err, &last);
2123 if (skb)
2124 break;
2125
2126 mutex_unlock(&u->iolock);
2127
2128 if (err != -EAGAIN)
2129 break;
2130 } while (timeo &&
2131 !__skb_wait_for_more_packets(sk, &err, &timeo, last));
2132
2133 if (!skb) { /* implies iolock unlocked */
2134 unix_state_lock(sk);
2135 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2136 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2137 (sk->sk_shutdown & RCV_SHUTDOWN))
2138 err = 0;
2139 unix_state_unlock(sk);
2140 goto out;
2141 }
2142
2143 if (wq_has_sleeper(&u->peer_wait))
2144 wake_up_interruptible_sync_poll(&u->peer_wait,
2145 POLLOUT | POLLWRNORM |
2146 POLLWRBAND);
2147
2148 if (msg->msg_name)
2149 unix_copy_addr(msg, skb->sk);
2150
2151 if (size > skb->len - skip)
2152 size = skb->len - skip;
2153 else if (size < skb->len - skip)
2154 msg->msg_flags |= MSG_TRUNC;
2155
2156 err = skb_copy_datagram_msg(skb, skip, msg, size);
2157 if (err)
2158 goto out_free;
2159
2160 if (sock_flag(sk, SOCK_RCVTSTAMP))
2161 __sock_recv_timestamp(msg, sk, skb);
2162
2163 memset(&scm, 0, sizeof(scm));
2164
2165 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2166 unix_set_secdata(&scm, skb);
2167
2168 if (!(flags & MSG_PEEK)) {
2169 if (UNIXCB(skb).fp)
2170 unix_detach_fds(&scm, skb);
2171
2172 sk_peek_offset_bwd(sk, skb->len);
2173 } else {
2174 /* It is questionable: on PEEK we could:
2175 - do not return fds - good, but too simple 8)
2176 - return fds, and do not return them on read (old strategy,
2177 apparently wrong)
2178 - clone fds (I chose it for now, it is the most universal
2179 solution)
2180
2181 POSIX 1003.1g does not actually define this clearly
2182 at all. POSIX 1003.1g doesn't define a lot of things
2183 clearly however!
2184
2185 */
2186
2187 sk_peek_offset_fwd(sk, size);
2188
2189 if (UNIXCB(skb).fp)
2190 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2191 }
2192 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2193
2194 scm_recv(sock, msg, &scm, flags);
2195
2196out_free:
2197 skb_free_datagram(sk, skb);
2198 mutex_unlock(&u->iolock);
2199out:
2200 return err;
2201}
2202
2203/*
2204 * Sleep until more data has arrived. But check for races..
2205 */
2206static long unix_stream_data_wait(struct sock *sk, long timeo,
2207 struct sk_buff *last, unsigned int last_len,
2208 bool freezable)
2209{
2210 struct sk_buff *tail;
2211 DEFINE_WAIT(wait);
2212
2213 unix_state_lock(sk);
2214
2215 for (;;) {
2216 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2217
2218 tail = skb_peek_tail(&sk->sk_receive_queue);
2219 if (tail != last ||
2220 (tail && tail->len != last_len) ||
2221 sk->sk_err ||
2222 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2223 signal_pending(current) ||
2224 !timeo)
2225 break;
2226
2227 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2228 unix_state_unlock(sk);
2229 if (freezable)
2230 timeo = freezable_schedule_timeout(timeo);
2231 else
2232 timeo = schedule_timeout(timeo);
2233 unix_state_lock(sk);
2234
2235 if (sock_flag(sk, SOCK_DEAD))
2236 break;
2237
2238 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2239 }
2240
2241 finish_wait(sk_sleep(sk), &wait);
2242 unix_state_unlock(sk);
2243 return timeo;
2244}
2245
2246static unsigned int unix_skb_len(const struct sk_buff *skb)
2247{
2248 return skb->len - UNIXCB(skb).consumed;
2249}
2250
2251struct unix_stream_read_state {
2252 int (*recv_actor)(struct sk_buff *, int, int,
2253 struct unix_stream_read_state *);
2254 struct socket *socket;
2255 struct msghdr *msg;
2256 struct pipe_inode_info *pipe;
2257 size_t size;
2258 int flags;
2259 unsigned int splice_flags;
2260};
2261
2262static int unix_stream_read_generic(struct unix_stream_read_state *state,
2263 bool freezable)
2264{
2265 struct scm_cookie scm;
2266 struct socket *sock = state->socket;
2267 struct sock *sk = sock->sk;
2268 struct unix_sock *u = unix_sk(sk);
2269 int copied = 0;
2270 int flags = state->flags;
2271 int noblock = flags & MSG_DONTWAIT;
2272 bool check_creds = false;
2273 int target;
2274 int err = 0;
2275 long timeo;
2276 int skip;
2277 size_t size = state->size;
2278 unsigned int last_len;
2279
2280 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2281 err = -EINVAL;
2282 goto out;
2283 }
2284
2285 if (unlikely(flags & MSG_OOB)) {
2286 err = -EOPNOTSUPP;
2287 goto out;
2288 }
2289
2290 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2291 timeo = sock_rcvtimeo(sk, noblock);
2292
2293 memset(&scm, 0, sizeof(scm));
2294
2295 /* Lock the socket to prevent queue disordering
2296 * while sleeps in memcpy_tomsg
2297 */
2298 mutex_lock(&u->iolock);
2299
2300 if (flags & MSG_PEEK)
2301 skip = sk_peek_offset(sk, flags);
2302 else
2303 skip = 0;
2304
2305 do {
2306 int chunk;
2307 bool drop_skb;
2308 struct sk_buff *skb, *last;
2309
2310redo:
2311 unix_state_lock(sk);
2312 if (sock_flag(sk, SOCK_DEAD)) {
2313 err = -ECONNRESET;
2314 goto unlock;
2315 }
2316 last = skb = skb_peek(&sk->sk_receive_queue);
2317 last_len = last ? last->len : 0;
2318again:
2319 if (skb == NULL) {
2320 unix_sk(sk)->recursion_level = 0;
2321 if (copied >= target)
2322 goto unlock;
2323
2324 /*
2325 * POSIX 1003.1g mandates this order.
2326 */
2327
2328 err = sock_error(sk);
2329 if (err)
2330 goto unlock;
2331 if (sk->sk_shutdown & RCV_SHUTDOWN)
2332 goto unlock;
2333
2334 unix_state_unlock(sk);
2335 if (!timeo) {
2336 err = -EAGAIN;
2337 break;
2338 }
2339
2340 mutex_unlock(&u->iolock);
2341
2342 timeo = unix_stream_data_wait(sk, timeo, last,
2343 last_len, freezable);
2344
2345 if (signal_pending(current)) {
2346 err = sock_intr_errno(timeo);
2347 scm_destroy(&scm);
2348 goto out;
2349 }
2350
2351 mutex_lock(&u->iolock);
2352 goto redo;
2353unlock:
2354 unix_state_unlock(sk);
2355 break;
2356 }
2357
2358 while (skip >= unix_skb_len(skb)) {
2359 skip -= unix_skb_len(skb);
2360 last = skb;
2361 last_len = skb->len;
2362 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2363 if (!skb)
2364 goto again;
2365 }
2366
2367 unix_state_unlock(sk);
2368
2369 if (check_creds) {
2370 /* Never glue messages from different writers */
2371 if (!unix_skb_scm_eq(skb, &scm))
2372 break;
2373 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2374 /* Copy credentials */
2375 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2376 unix_set_secdata(&scm, skb);
2377 check_creds = true;
2378 }
2379
2380 /* Copy address just once */
2381 if (state->msg && state->msg->msg_name) {
2382 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2383 state->msg->msg_name);
2384 unix_copy_addr(state->msg, skb->sk);
2385 sunaddr = NULL;
2386 }
2387
2388 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2389 skb_get(skb);
2390 chunk = state->recv_actor(skb, skip, chunk, state);
2391 drop_skb = !unix_skb_len(skb);
2392 /* skb is only safe to use if !drop_skb */
2393 consume_skb(skb);
2394 if (chunk < 0) {
2395 if (copied == 0)
2396 copied = -EFAULT;
2397 break;
2398 }
2399 copied += chunk;
2400 size -= chunk;
2401
2402 if (drop_skb) {
2403 /* the skb was touched by a concurrent reader;
2404 * we should not expect anything from this skb
2405 * anymore and assume it invalid - we can be
2406 * sure it was dropped from the socket queue
2407 *
2408 * let's report a short read
2409 */
2410 err = 0;
2411 break;
2412 }
2413
2414 /* Mark read part of skb as used */
2415 if (!(flags & MSG_PEEK)) {
2416 UNIXCB(skb).consumed += chunk;
2417
2418 sk_peek_offset_bwd(sk, chunk);
2419
2420 if (UNIXCB(skb).fp)
2421 unix_detach_fds(&scm, skb);
2422
2423 if (unix_skb_len(skb))
2424 break;
2425
2426 skb_unlink(skb, &sk->sk_receive_queue);
2427 consume_skb(skb);
2428
2429 if (scm.fp)
2430 break;
2431 } else {
2432 /* It is questionable, see note in unix_dgram_recvmsg.
2433 */
2434 if (UNIXCB(skb).fp)
2435 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2436
2437 sk_peek_offset_fwd(sk, chunk);
2438
2439 if (UNIXCB(skb).fp)
2440 break;
2441
2442 skip = 0;
2443 last = skb;
2444 last_len = skb->len;
2445 unix_state_lock(sk);
2446 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2447 if (skb)
2448 goto again;
2449 unix_state_unlock(sk);
2450 break;
2451 }
2452 } while (size);
2453
2454 mutex_unlock(&u->iolock);
2455 if (state->msg)
2456 scm_recv(sock, state->msg, &scm, flags);
2457 else
2458 scm_destroy(&scm);
2459out:
2460 return copied ? : err;
2461}
2462
2463static int unix_stream_read_actor(struct sk_buff *skb,
2464 int skip, int chunk,
2465 struct unix_stream_read_state *state)
2466{
2467 int ret;
2468
2469 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2470 state->msg, chunk);
2471 return ret ?: chunk;
2472}
2473
2474static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2475 size_t size, int flags)
2476{
2477 struct unix_stream_read_state state = {
2478 .recv_actor = unix_stream_read_actor,
2479 .socket = sock,
2480 .msg = msg,
2481 .size = size,
2482 .flags = flags
2483 };
2484
2485 return unix_stream_read_generic(&state, true);
2486}
2487
2488static int unix_stream_splice_actor(struct sk_buff *skb,
2489 int skip, int chunk,
2490 struct unix_stream_read_state *state)
2491{
2492 return skb_splice_bits(skb, state->socket->sk,
2493 UNIXCB(skb).consumed + skip,
2494 state->pipe, chunk, state->splice_flags);
2495}
2496
2497static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2498 struct pipe_inode_info *pipe,
2499 size_t size, unsigned int flags)
2500{
2501 struct unix_stream_read_state state = {
2502 .recv_actor = unix_stream_splice_actor,
2503 .socket = sock,
2504 .pipe = pipe,
2505 .size = size,
2506 .splice_flags = flags,
2507 };
2508
2509 if (unlikely(*ppos))
2510 return -ESPIPE;
2511
2512 if (sock->file->f_flags & O_NONBLOCK ||
2513 flags & SPLICE_F_NONBLOCK)
2514 state.flags = MSG_DONTWAIT;
2515
2516 return unix_stream_read_generic(&state, false);
2517}
2518
2519static int unix_shutdown(struct socket *sock, int mode)
2520{
2521 struct sock *sk = sock->sk;
2522 struct sock *other;
2523
2524 if (mode < SHUT_RD || mode > SHUT_RDWR)
2525 return -EINVAL;
2526 /* This maps:
2527 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2528 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2529 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2530 */
2531 ++mode;
2532
2533 unix_state_lock(sk);
2534 sk->sk_shutdown |= mode;
2535 other = unix_peer(sk);
2536 if (other)
2537 sock_hold(other);
2538 unix_state_unlock(sk);
2539 sk->sk_state_change(sk);
2540
2541 if (other &&
2542 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2543
2544 int peer_mode = 0;
2545
2546 if (mode&RCV_SHUTDOWN)
2547 peer_mode |= SEND_SHUTDOWN;
2548 if (mode&SEND_SHUTDOWN)
2549 peer_mode |= RCV_SHUTDOWN;
2550 unix_state_lock(other);
2551 other->sk_shutdown |= peer_mode;
2552 unix_state_unlock(other);
2553 other->sk_state_change(other);
2554 if (peer_mode == SHUTDOWN_MASK)
2555 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2556 else if (peer_mode & RCV_SHUTDOWN)
2557 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2558 }
2559 if (other)
2560 sock_put(other);
2561
2562 return 0;
2563}
2564
2565long unix_inq_len(struct sock *sk)
2566{
2567 struct sk_buff *skb;
2568 long amount = 0;
2569
2570 if (sk->sk_state == TCP_LISTEN)
2571 return -EINVAL;
2572
2573 spin_lock(&sk->sk_receive_queue.lock);
2574 if (sk->sk_type == SOCK_STREAM ||
2575 sk->sk_type == SOCK_SEQPACKET) {
2576 skb_queue_walk(&sk->sk_receive_queue, skb)
2577 amount += unix_skb_len(skb);
2578 } else {
2579 skb = skb_peek(&sk->sk_receive_queue);
2580 if (skb)
2581 amount = skb->len;
2582 }
2583 spin_unlock(&sk->sk_receive_queue.lock);
2584
2585 return amount;
2586}
2587EXPORT_SYMBOL_GPL(unix_inq_len);
2588
2589long unix_outq_len(struct sock *sk)
2590{
2591 return sk_wmem_alloc_get(sk);
2592}
2593EXPORT_SYMBOL_GPL(unix_outq_len);
2594
2595static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2596{
2597 struct sock *sk = sock->sk;
2598 long amount = 0;
2599 int err;
2600
2601 switch (cmd) {
2602 case SIOCOUTQ:
2603 amount = unix_outq_len(sk);
2604 err = put_user(amount, (int __user *)arg);
2605 break;
2606 case SIOCINQ:
2607 amount = unix_inq_len(sk);
2608 if (amount < 0)
2609 err = amount;
2610 else
2611 err = put_user(amount, (int __user *)arg);
2612 break;
2613 default:
2614 err = -ENOIOCTLCMD;
2615 break;
2616 }
2617 return err;
2618}
2619
2620static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2621{
2622 struct sock *sk = sock->sk;
2623 unsigned int mask;
2624
2625 sock_poll_wait(file, sk_sleep(sk), wait);
2626 mask = 0;
2627
2628 /* exceptional events? */
2629 if (sk->sk_err)
2630 mask |= POLLERR;
2631 if (sk->sk_shutdown == SHUTDOWN_MASK)
2632 mask |= POLLHUP;
2633 if (sk->sk_shutdown & RCV_SHUTDOWN)
2634 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2635
2636 /* readable? */
2637 if (!skb_queue_empty(&sk->sk_receive_queue))
2638 mask |= POLLIN | POLLRDNORM;
2639
2640 /* Connection-based need to check for termination and startup */
2641 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2642 sk->sk_state == TCP_CLOSE)
2643 mask |= POLLHUP;
2644
2645 /*
2646 * we set writable also when the other side has shut down the
2647 * connection. This prevents stuck sockets.
2648 */
2649 if (unix_writable(sk))
2650 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2651
2652 return mask;
2653}
2654
2655static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2656 poll_table *wait)
2657{
2658 struct sock *sk = sock->sk, *other;
2659 unsigned int mask, writable;
2660
2661 sock_poll_wait(file, sk_sleep(sk), wait);
2662 mask = 0;
2663
2664 /* exceptional events? */
2665 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2666 mask |= POLLERR |
2667 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2668
2669 if (sk->sk_shutdown & RCV_SHUTDOWN)
2670 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2671 if (sk->sk_shutdown == SHUTDOWN_MASK)
2672 mask |= POLLHUP;
2673
2674 /* readable? */
2675 if (!skb_queue_empty(&sk->sk_receive_queue))
2676 mask |= POLLIN | POLLRDNORM;
2677
2678 /* Connection-based need to check for termination and startup */
2679 if (sk->sk_type == SOCK_SEQPACKET) {
2680 if (sk->sk_state == TCP_CLOSE)
2681 mask |= POLLHUP;
2682 /* connection hasn't started yet? */
2683 if (sk->sk_state == TCP_SYN_SENT)
2684 return mask;
2685 }
2686
2687 /* No write status requested, avoid expensive OUT tests. */
2688 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
2689 return mask;
2690
2691 writable = unix_writable(sk);
2692 if (writable) {
2693 unix_state_lock(sk);
2694
2695 other = unix_peer(sk);
2696 if (other && unix_peer(other) != sk &&
2697 unix_recvq_full(other) &&
2698 unix_dgram_peer_wake_me(sk, other))
2699 writable = 0;
2700
2701 unix_state_unlock(sk);
2702 }
2703
2704 if (writable)
2705 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2706 else
2707 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2708
2709 return mask;
2710}
2711
2712#ifdef CONFIG_PROC_FS
2713
2714#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2715
2716#define get_bucket(x) ((x) >> BUCKET_SPACE)
2717#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2718#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2719
2720static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2721{
2722 unsigned long offset = get_offset(*pos);
2723 unsigned long bucket = get_bucket(*pos);
2724 struct sock *sk;
2725 unsigned long count = 0;
2726
2727 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2728 if (sock_net(sk) != seq_file_net(seq))
2729 continue;
2730 if (++count == offset)
2731 break;
2732 }
2733
2734 return sk;
2735}
2736
2737static struct sock *unix_next_socket(struct seq_file *seq,
2738 struct sock *sk,
2739 loff_t *pos)
2740{
2741 unsigned long bucket;
2742
2743 while (sk > (struct sock *)SEQ_START_TOKEN) {
2744 sk = sk_next(sk);
2745 if (!sk)
2746 goto next_bucket;
2747 if (sock_net(sk) == seq_file_net(seq))
2748 return sk;
2749 }
2750
2751 do {
2752 sk = unix_from_bucket(seq, pos);
2753 if (sk)
2754 return sk;
2755
2756next_bucket:
2757 bucket = get_bucket(*pos) + 1;
2758 *pos = set_bucket_offset(bucket, 1);
2759 } while (bucket < ARRAY_SIZE(unix_socket_table));
2760
2761 return NULL;
2762}
2763
2764static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2765 __acquires(unix_table_lock)
2766{
2767 spin_lock(&unix_table_lock);
2768
2769 if (!*pos)
2770 return SEQ_START_TOKEN;
2771
2772 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2773 return NULL;
2774
2775 return unix_next_socket(seq, NULL, pos);
2776}
2777
2778static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2779{
2780 ++*pos;
2781 return unix_next_socket(seq, v, pos);
2782}
2783
2784static void unix_seq_stop(struct seq_file *seq, void *v)
2785 __releases(unix_table_lock)
2786{
2787 spin_unlock(&unix_table_lock);
2788}
2789
2790static int unix_seq_show(struct seq_file *seq, void *v)
2791{
2792
2793 if (v == SEQ_START_TOKEN)
2794 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2795 "Inode Path\n");
2796 else {
2797 struct sock *s = v;
2798 struct unix_sock *u = unix_sk(s);
2799 unix_state_lock(s);
2800
2801 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2802 s,
2803 atomic_read(&s->sk_refcnt),
2804 0,
2805 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2806 s->sk_type,
2807 s->sk_socket ?
2808 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2809 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2810 sock_i_ino(s));
2811
2812 if (u->addr) {
2813 int i, len;
2814 seq_putc(seq, ' ');
2815
2816 i = 0;
2817 len = u->addr->len - sizeof(short);
2818 if (!UNIX_ABSTRACT(s))
2819 len--;
2820 else {
2821 seq_putc(seq, '@');
2822 i++;
2823 }
2824 for ( ; i < len; i++)
2825 seq_putc(seq, u->addr->name->sun_path[i] ?:
2826 '@');
2827 }
2828 unix_state_unlock(s);
2829 seq_putc(seq, '\n');
2830 }
2831
2832 return 0;
2833}
2834
2835static const struct seq_operations unix_seq_ops = {
2836 .start = unix_seq_start,
2837 .next = unix_seq_next,
2838 .stop = unix_seq_stop,
2839 .show = unix_seq_show,
2840};
2841
2842static int unix_seq_open(struct inode *inode, struct file *file)
2843{
2844 return seq_open_net(inode, file, &unix_seq_ops,
2845 sizeof(struct seq_net_private));
2846}
2847
2848static const struct file_operations unix_seq_fops = {
2849 .owner = THIS_MODULE,
2850 .open = unix_seq_open,
2851 .read = seq_read,
2852 .llseek = seq_lseek,
2853 .release = seq_release_net,
2854};
2855
2856#endif
2857
2858static const struct net_proto_family unix_family_ops = {
2859 .family = PF_UNIX,
2860 .create = unix_create,
2861 .owner = THIS_MODULE,
2862};
2863
2864
2865static int __net_init unix_net_init(struct net *net)
2866{
2867 int error = -ENOMEM;
2868
2869 net->unx.sysctl_max_dgram_qlen = 10;
2870 if (unix_sysctl_register(net))
2871 goto out;
2872
2873#ifdef CONFIG_PROC_FS
2874 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2875 unix_sysctl_unregister(net);
2876 goto out;
2877 }
2878#endif
2879 error = 0;
2880out:
2881 return error;
2882}
2883
2884static void __net_exit unix_net_exit(struct net *net)
2885{
2886 unix_sysctl_unregister(net);
2887 remove_proc_entry("unix", net->proc_net);
2888}
2889
2890static struct pernet_operations unix_net_ops = {
2891 .init = unix_net_init,
2892 .exit = unix_net_exit,
2893};
2894
2895static int __init af_unix_init(void)
2896{
2897 int rc = -1;
2898
2899 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2900
2901 rc = proto_register(&unix_proto, 1);
2902 if (rc != 0) {
2903 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
2904 goto out;
2905 }
2906
2907 sock_register(&unix_family_ops);
2908 register_pernet_subsys(&unix_net_ops);
2909out:
2910 return rc;
2911}
2912
2913static void __exit af_unix_exit(void)
2914{
2915 sock_unregister(PF_UNIX);
2916 proto_unregister(&unix_proto);
2917 unregister_pernet_subsys(&unix_net_ops);
2918}
2919
2920/* Earlier than device_initcall() so that other drivers invoking
2921 request_module() don't end up in a loop when modprobe tries
2922 to use a UNIX socket. But later than subsys_initcall() because
2923 we depend on stuff initialised there */
2924fs_initcall(af_unix_init);
2925module_exit(af_unix_exit);
2926
2927MODULE_LICENSE("GPL");
2928MODULE_ALIAS_NETPROTO(PF_UNIX);
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#include <linux/module.h>
84#include <linux/kernel.h>
85#include <linux/signal.h>
86#include <linux/sched.h>
87#include <linux/errno.h>
88#include <linux/string.h>
89#include <linux/stat.h>
90#include <linux/dcache.h>
91#include <linux/namei.h>
92#include <linux/socket.h>
93#include <linux/un.h>
94#include <linux/fcntl.h>
95#include <linux/termios.h>
96#include <linux/sockios.h>
97#include <linux/net.h>
98#include <linux/in.h>
99#include <linux/fs.h>
100#include <linux/slab.h>
101#include <asm/uaccess.h>
102#include <linux/skbuff.h>
103#include <linux/netdevice.h>
104#include <net/net_namespace.h>
105#include <net/sock.h>
106#include <net/tcp_states.h>
107#include <net/af_unix.h>
108#include <linux/proc_fs.h>
109#include <linux/seq_file.h>
110#include <net/scm.h>
111#include <linux/init.h>
112#include <linux/poll.h>
113#include <linux/rtnetlink.h>
114#include <linux/mount.h>
115#include <net/checksum.h>
116#include <linux/security.h>
117
118struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
119EXPORT_SYMBOL_GPL(unix_socket_table);
120DEFINE_SPINLOCK(unix_table_lock);
121EXPORT_SYMBOL_GPL(unix_table_lock);
122static atomic_long_t unix_nr_socks;
123
124#define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE])
125
126#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
127
128#ifdef CONFIG_SECURITY_NETWORK
129static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
130{
131 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
132}
133
134static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
135{
136 scm->secid = *UNIXSID(skb);
137}
138#else
139static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
140{ }
141
142static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
143{ }
144#endif /* CONFIG_SECURITY_NETWORK */
145
146/*
147 * SMP locking strategy:
148 * hash table is protected with spinlock unix_table_lock
149 * each socket state is protected by separate spin lock.
150 */
151
152static inline unsigned int unix_hash_fold(__wsum n)
153{
154 unsigned int hash = (__force unsigned int)n;
155
156 hash ^= hash>>16;
157 hash ^= hash>>8;
158 return hash&(UNIX_HASH_SIZE-1);
159}
160
161#define unix_peer(sk) (unix_sk(sk)->peer)
162
163static inline int unix_our_peer(struct sock *sk, struct sock *osk)
164{
165 return unix_peer(osk) == sk;
166}
167
168static inline int unix_may_send(struct sock *sk, struct sock *osk)
169{
170 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
171}
172
173static inline int unix_recvq_full(struct sock const *sk)
174{
175 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
176}
177
178struct sock *unix_peer_get(struct sock *s)
179{
180 struct sock *peer;
181
182 unix_state_lock(s);
183 peer = unix_peer(s);
184 if (peer)
185 sock_hold(peer);
186 unix_state_unlock(s);
187 return peer;
188}
189EXPORT_SYMBOL_GPL(unix_peer_get);
190
191static inline void unix_release_addr(struct unix_address *addr)
192{
193 if (atomic_dec_and_test(&addr->refcnt))
194 kfree(addr);
195}
196
197/*
198 * Check unix socket name:
199 * - should be not zero length.
200 * - if started by not zero, should be NULL terminated (FS object)
201 * - if started by zero, it is abstract name.
202 */
203
204static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
205{
206 if (len <= sizeof(short) || len > sizeof(*sunaddr))
207 return -EINVAL;
208 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
209 return -EINVAL;
210 if (sunaddr->sun_path[0]) {
211 /*
212 * This may look like an off by one error but it is a bit more
213 * subtle. 108 is the longest valid AF_UNIX path for a binding.
214 * sun_path[108] doesn't as such exist. However in kernel space
215 * we are guaranteed that it is a valid memory location in our
216 * kernel address buffer.
217 */
218 ((char *)sunaddr)[len] = 0;
219 len = strlen(sunaddr->sun_path)+1+sizeof(short);
220 return len;
221 }
222
223 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
224 return len;
225}
226
227static void __unix_remove_socket(struct sock *sk)
228{
229 sk_del_node_init(sk);
230}
231
232static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
233{
234 WARN_ON(!sk_unhashed(sk));
235 sk_add_node(sk, list);
236}
237
238static inline void unix_remove_socket(struct sock *sk)
239{
240 spin_lock(&unix_table_lock);
241 __unix_remove_socket(sk);
242 spin_unlock(&unix_table_lock);
243}
244
245static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
246{
247 spin_lock(&unix_table_lock);
248 __unix_insert_socket(list, sk);
249 spin_unlock(&unix_table_lock);
250}
251
252static struct sock *__unix_find_socket_byname(struct net *net,
253 struct sockaddr_un *sunname,
254 int len, int type, unsigned int hash)
255{
256 struct sock *s;
257 struct hlist_node *node;
258
259 sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
260 struct unix_sock *u = unix_sk(s);
261
262 if (!net_eq(sock_net(s), net))
263 continue;
264
265 if (u->addr->len == len &&
266 !memcmp(u->addr->name, sunname, len))
267 goto found;
268 }
269 s = NULL;
270found:
271 return s;
272}
273
274static inline struct sock *unix_find_socket_byname(struct net *net,
275 struct sockaddr_un *sunname,
276 int len, int type,
277 unsigned int hash)
278{
279 struct sock *s;
280
281 spin_lock(&unix_table_lock);
282 s = __unix_find_socket_byname(net, sunname, len, type, hash);
283 if (s)
284 sock_hold(s);
285 spin_unlock(&unix_table_lock);
286 return s;
287}
288
289static struct sock *unix_find_socket_byinode(struct inode *i)
290{
291 struct sock *s;
292 struct hlist_node *node;
293
294 spin_lock(&unix_table_lock);
295 sk_for_each(s, node,
296 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
297 struct dentry *dentry = unix_sk(s)->path.dentry;
298
299 if (dentry && dentry->d_inode == i) {
300 sock_hold(s);
301 goto found;
302 }
303 }
304 s = NULL;
305found:
306 spin_unlock(&unix_table_lock);
307 return s;
308}
309
310static inline int unix_writable(struct sock *sk)
311{
312 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
313}
314
315static void unix_write_space(struct sock *sk)
316{
317 struct socket_wq *wq;
318
319 rcu_read_lock();
320 if (unix_writable(sk)) {
321 wq = rcu_dereference(sk->sk_wq);
322 if (wq_has_sleeper(wq))
323 wake_up_interruptible_sync_poll(&wq->wait,
324 POLLOUT | POLLWRNORM | POLLWRBAND);
325 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
326 }
327 rcu_read_unlock();
328}
329
330/* When dgram socket disconnects (or changes its peer), we clear its receive
331 * queue of packets arrived from previous peer. First, it allows to do
332 * flow control based only on wmem_alloc; second, sk connected to peer
333 * may receive messages only from that peer. */
334static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
335{
336 if (!skb_queue_empty(&sk->sk_receive_queue)) {
337 skb_queue_purge(&sk->sk_receive_queue);
338 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
339
340 /* If one link of bidirectional dgram pipe is disconnected,
341 * we signal error. Messages are lost. Do not make this,
342 * when peer was not connected to us.
343 */
344 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
345 other->sk_err = ECONNRESET;
346 other->sk_error_report(other);
347 }
348 }
349}
350
351static void unix_sock_destructor(struct sock *sk)
352{
353 struct unix_sock *u = unix_sk(sk);
354
355 skb_queue_purge(&sk->sk_receive_queue);
356
357 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
358 WARN_ON(!sk_unhashed(sk));
359 WARN_ON(sk->sk_socket);
360 if (!sock_flag(sk, SOCK_DEAD)) {
361 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk);
362 return;
363 }
364
365 if (u->addr)
366 unix_release_addr(u->addr);
367
368 atomic_long_dec(&unix_nr_socks);
369 local_bh_disable();
370 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
371 local_bh_enable();
372#ifdef UNIX_REFCNT_DEBUG
373 printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk,
374 atomic_long_read(&unix_nr_socks));
375#endif
376}
377
378static int unix_release_sock(struct sock *sk, int embrion)
379{
380 struct unix_sock *u = unix_sk(sk);
381 struct path path;
382 struct sock *skpair;
383 struct sk_buff *skb;
384 int state;
385
386 unix_remove_socket(sk);
387
388 /* Clear state */
389 unix_state_lock(sk);
390 sock_orphan(sk);
391 sk->sk_shutdown = SHUTDOWN_MASK;
392 path = u->path;
393 u->path.dentry = NULL;
394 u->path.mnt = NULL;
395 state = sk->sk_state;
396 sk->sk_state = TCP_CLOSE;
397 unix_state_unlock(sk);
398
399 wake_up_interruptible_all(&u->peer_wait);
400
401 skpair = unix_peer(sk);
402
403 if (skpair != NULL) {
404 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
405 unix_state_lock(skpair);
406 /* No more writes */
407 skpair->sk_shutdown = SHUTDOWN_MASK;
408 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
409 skpair->sk_err = ECONNRESET;
410 unix_state_unlock(skpair);
411 skpair->sk_state_change(skpair);
412 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
413 }
414 sock_put(skpair); /* It may now die */
415 unix_peer(sk) = NULL;
416 }
417
418 /* Try to flush out this socket. Throw out buffers at least */
419
420 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
421 if (state == TCP_LISTEN)
422 unix_release_sock(skb->sk, 1);
423 /* passed fds are erased in the kfree_skb hook */
424 kfree_skb(skb);
425 }
426
427 if (path.dentry)
428 path_put(&path);
429
430 sock_put(sk);
431
432 /* ---- Socket is dead now and most probably destroyed ---- */
433
434 /*
435 * Fixme: BSD difference: In BSD all sockets connected to use get
436 * ECONNRESET and we die on the spot. In Linux we behave
437 * like files and pipes do and wait for the last
438 * dereference.
439 *
440 * Can't we simply set sock->err?
441 *
442 * What the above comment does talk about? --ANK(980817)
443 */
444
445 if (unix_tot_inflight)
446 unix_gc(); /* Garbage collect fds */
447
448 return 0;
449}
450
451static void init_peercred(struct sock *sk)
452{
453 put_pid(sk->sk_peer_pid);
454 if (sk->sk_peer_cred)
455 put_cred(sk->sk_peer_cred);
456 sk->sk_peer_pid = get_pid(task_tgid(current));
457 sk->sk_peer_cred = get_current_cred();
458}
459
460static void copy_peercred(struct sock *sk, struct sock *peersk)
461{
462 put_pid(sk->sk_peer_pid);
463 if (sk->sk_peer_cred)
464 put_cred(sk->sk_peer_cred);
465 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
466 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
467}
468
469static int unix_listen(struct socket *sock, int backlog)
470{
471 int err;
472 struct sock *sk = sock->sk;
473 struct unix_sock *u = unix_sk(sk);
474 struct pid *old_pid = NULL;
475 const struct cred *old_cred = NULL;
476
477 err = -EOPNOTSUPP;
478 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
479 goto out; /* Only stream/seqpacket sockets accept */
480 err = -EINVAL;
481 if (!u->addr)
482 goto out; /* No listens on an unbound socket */
483 unix_state_lock(sk);
484 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
485 goto out_unlock;
486 if (backlog > sk->sk_max_ack_backlog)
487 wake_up_interruptible_all(&u->peer_wait);
488 sk->sk_max_ack_backlog = backlog;
489 sk->sk_state = TCP_LISTEN;
490 /* set credentials so connect can copy them */
491 init_peercred(sk);
492 err = 0;
493
494out_unlock:
495 unix_state_unlock(sk);
496 put_pid(old_pid);
497 if (old_cred)
498 put_cred(old_cred);
499out:
500 return err;
501}
502
503static int unix_release(struct socket *);
504static int unix_bind(struct socket *, struct sockaddr *, int);
505static int unix_stream_connect(struct socket *, struct sockaddr *,
506 int addr_len, int flags);
507static int unix_socketpair(struct socket *, struct socket *);
508static int unix_accept(struct socket *, struct socket *, int);
509static int unix_getname(struct socket *, struct sockaddr *, int *, int);
510static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
511static unsigned int unix_dgram_poll(struct file *, struct socket *,
512 poll_table *);
513static int unix_ioctl(struct socket *, unsigned int, unsigned long);
514static int unix_shutdown(struct socket *, int);
515static int unix_stream_sendmsg(struct kiocb *, struct socket *,
516 struct msghdr *, size_t);
517static int unix_stream_recvmsg(struct kiocb *, struct socket *,
518 struct msghdr *, size_t, int);
519static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
520 struct msghdr *, size_t);
521static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
522 struct msghdr *, size_t, int);
523static int unix_dgram_connect(struct socket *, struct sockaddr *,
524 int, int);
525static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
526 struct msghdr *, size_t);
527static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
528 struct msghdr *, size_t, int);
529
530static void unix_set_peek_off(struct sock *sk, int val)
531{
532 struct unix_sock *u = unix_sk(sk);
533
534 mutex_lock(&u->readlock);
535 sk->sk_peek_off = val;
536 mutex_unlock(&u->readlock);
537}
538
539
540static const struct proto_ops unix_stream_ops = {
541 .family = PF_UNIX,
542 .owner = THIS_MODULE,
543 .release = unix_release,
544 .bind = unix_bind,
545 .connect = unix_stream_connect,
546 .socketpair = unix_socketpair,
547 .accept = unix_accept,
548 .getname = unix_getname,
549 .poll = unix_poll,
550 .ioctl = unix_ioctl,
551 .listen = unix_listen,
552 .shutdown = unix_shutdown,
553 .setsockopt = sock_no_setsockopt,
554 .getsockopt = sock_no_getsockopt,
555 .sendmsg = unix_stream_sendmsg,
556 .recvmsg = unix_stream_recvmsg,
557 .mmap = sock_no_mmap,
558 .sendpage = sock_no_sendpage,
559 .set_peek_off = unix_set_peek_off,
560};
561
562static const struct proto_ops unix_dgram_ops = {
563 .family = PF_UNIX,
564 .owner = THIS_MODULE,
565 .release = unix_release,
566 .bind = unix_bind,
567 .connect = unix_dgram_connect,
568 .socketpair = unix_socketpair,
569 .accept = sock_no_accept,
570 .getname = unix_getname,
571 .poll = unix_dgram_poll,
572 .ioctl = unix_ioctl,
573 .listen = sock_no_listen,
574 .shutdown = unix_shutdown,
575 .setsockopt = sock_no_setsockopt,
576 .getsockopt = sock_no_getsockopt,
577 .sendmsg = unix_dgram_sendmsg,
578 .recvmsg = unix_dgram_recvmsg,
579 .mmap = sock_no_mmap,
580 .sendpage = sock_no_sendpage,
581 .set_peek_off = unix_set_peek_off,
582};
583
584static const struct proto_ops unix_seqpacket_ops = {
585 .family = PF_UNIX,
586 .owner = THIS_MODULE,
587 .release = unix_release,
588 .bind = unix_bind,
589 .connect = unix_stream_connect,
590 .socketpair = unix_socketpair,
591 .accept = unix_accept,
592 .getname = unix_getname,
593 .poll = unix_dgram_poll,
594 .ioctl = unix_ioctl,
595 .listen = unix_listen,
596 .shutdown = unix_shutdown,
597 .setsockopt = sock_no_setsockopt,
598 .getsockopt = sock_no_getsockopt,
599 .sendmsg = unix_seqpacket_sendmsg,
600 .recvmsg = unix_seqpacket_recvmsg,
601 .mmap = sock_no_mmap,
602 .sendpage = sock_no_sendpage,
603 .set_peek_off = unix_set_peek_off,
604};
605
606static struct proto unix_proto = {
607 .name = "UNIX",
608 .owner = THIS_MODULE,
609 .obj_size = sizeof(struct unix_sock),
610};
611
612/*
613 * AF_UNIX sockets do not interact with hardware, hence they
614 * dont trigger interrupts - so it's safe for them to have
615 * bh-unsafe locking for their sk_receive_queue.lock. Split off
616 * this special lock-class by reinitializing the spinlock key:
617 */
618static struct lock_class_key af_unix_sk_receive_queue_lock_key;
619
620static struct sock *unix_create1(struct net *net, struct socket *sock)
621{
622 struct sock *sk = NULL;
623 struct unix_sock *u;
624
625 atomic_long_inc(&unix_nr_socks);
626 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
627 goto out;
628
629 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
630 if (!sk)
631 goto out;
632
633 sock_init_data(sock, sk);
634 lockdep_set_class(&sk->sk_receive_queue.lock,
635 &af_unix_sk_receive_queue_lock_key);
636
637 sk->sk_write_space = unix_write_space;
638 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
639 sk->sk_destruct = unix_sock_destructor;
640 u = unix_sk(sk);
641 u->path.dentry = NULL;
642 u->path.mnt = NULL;
643 spin_lock_init(&u->lock);
644 atomic_long_set(&u->inflight, 0);
645 INIT_LIST_HEAD(&u->link);
646 mutex_init(&u->readlock); /* single task reading lock */
647 init_waitqueue_head(&u->peer_wait);
648 unix_insert_socket(unix_sockets_unbound, sk);
649out:
650 if (sk == NULL)
651 atomic_long_dec(&unix_nr_socks);
652 else {
653 local_bh_disable();
654 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
655 local_bh_enable();
656 }
657 return sk;
658}
659
660static int unix_create(struct net *net, struct socket *sock, int protocol,
661 int kern)
662{
663 if (protocol && protocol != PF_UNIX)
664 return -EPROTONOSUPPORT;
665
666 sock->state = SS_UNCONNECTED;
667
668 switch (sock->type) {
669 case SOCK_STREAM:
670 sock->ops = &unix_stream_ops;
671 break;
672 /*
673 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
674 * nothing uses it.
675 */
676 case SOCK_RAW:
677 sock->type = SOCK_DGRAM;
678 case SOCK_DGRAM:
679 sock->ops = &unix_dgram_ops;
680 break;
681 case SOCK_SEQPACKET:
682 sock->ops = &unix_seqpacket_ops;
683 break;
684 default:
685 return -ESOCKTNOSUPPORT;
686 }
687
688 return unix_create1(net, sock) ? 0 : -ENOMEM;
689}
690
691static int unix_release(struct socket *sock)
692{
693 struct sock *sk = sock->sk;
694
695 if (!sk)
696 return 0;
697
698 sock->sk = NULL;
699
700 return unix_release_sock(sk, 0);
701}
702
703static int unix_autobind(struct socket *sock)
704{
705 struct sock *sk = sock->sk;
706 struct net *net = sock_net(sk);
707 struct unix_sock *u = unix_sk(sk);
708 static u32 ordernum = 1;
709 struct unix_address *addr;
710 int err;
711 unsigned int retries = 0;
712
713 mutex_lock(&u->readlock);
714
715 err = 0;
716 if (u->addr)
717 goto out;
718
719 err = -ENOMEM;
720 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
721 if (!addr)
722 goto out;
723
724 addr->name->sun_family = AF_UNIX;
725 atomic_set(&addr->refcnt, 1);
726
727retry:
728 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
729 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
730
731 spin_lock(&unix_table_lock);
732 ordernum = (ordernum+1)&0xFFFFF;
733
734 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
735 addr->hash)) {
736 spin_unlock(&unix_table_lock);
737 /*
738 * __unix_find_socket_byname() may take long time if many names
739 * are already in use.
740 */
741 cond_resched();
742 /* Give up if all names seems to be in use. */
743 if (retries++ == 0xFFFFF) {
744 err = -ENOSPC;
745 kfree(addr);
746 goto out;
747 }
748 goto retry;
749 }
750 addr->hash ^= sk->sk_type;
751
752 __unix_remove_socket(sk);
753 u->addr = addr;
754 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
755 spin_unlock(&unix_table_lock);
756 err = 0;
757
758out: mutex_unlock(&u->readlock);
759 return err;
760}
761
762static struct sock *unix_find_other(struct net *net,
763 struct sockaddr_un *sunname, int len,
764 int type, unsigned int hash, int *error)
765{
766 struct sock *u;
767 struct path path;
768 int err = 0;
769
770 if (sunname->sun_path[0]) {
771 struct inode *inode;
772 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
773 if (err)
774 goto fail;
775 inode = path.dentry->d_inode;
776 err = inode_permission(inode, MAY_WRITE);
777 if (err)
778 goto put_fail;
779
780 err = -ECONNREFUSED;
781 if (!S_ISSOCK(inode->i_mode))
782 goto put_fail;
783 u = unix_find_socket_byinode(inode);
784 if (!u)
785 goto put_fail;
786
787 if (u->sk_type == type)
788 touch_atime(&path);
789
790 path_put(&path);
791
792 err = -EPROTOTYPE;
793 if (u->sk_type != type) {
794 sock_put(u);
795 goto fail;
796 }
797 } else {
798 err = -ECONNREFUSED;
799 u = unix_find_socket_byname(net, sunname, len, type, hash);
800 if (u) {
801 struct dentry *dentry;
802 dentry = unix_sk(u)->path.dentry;
803 if (dentry)
804 touch_atime(&unix_sk(u)->path);
805 } else
806 goto fail;
807 }
808 return u;
809
810put_fail:
811 path_put(&path);
812fail:
813 *error = err;
814 return NULL;
815}
816
817
818static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
819{
820 struct sock *sk = sock->sk;
821 struct net *net = sock_net(sk);
822 struct unix_sock *u = unix_sk(sk);
823 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
824 char *sun_path = sunaddr->sun_path;
825 struct dentry *dentry = NULL;
826 struct path path;
827 int err;
828 unsigned int hash;
829 struct unix_address *addr;
830 struct hlist_head *list;
831
832 err = -EINVAL;
833 if (sunaddr->sun_family != AF_UNIX)
834 goto out;
835
836 if (addr_len == sizeof(short)) {
837 err = unix_autobind(sock);
838 goto out;
839 }
840
841 err = unix_mkname(sunaddr, addr_len, &hash);
842 if (err < 0)
843 goto out;
844 addr_len = err;
845
846 mutex_lock(&u->readlock);
847
848 err = -EINVAL;
849 if (u->addr)
850 goto out_up;
851
852 err = -ENOMEM;
853 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
854 if (!addr)
855 goto out_up;
856
857 memcpy(addr->name, sunaddr, addr_len);
858 addr->len = addr_len;
859 addr->hash = hash ^ sk->sk_type;
860 atomic_set(&addr->refcnt, 1);
861
862 if (sun_path[0]) {
863 umode_t mode;
864 err = 0;
865 /*
866 * Get the parent directory, calculate the hash for last
867 * component.
868 */
869 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
870 err = PTR_ERR(dentry);
871 if (IS_ERR(dentry))
872 goto out_mknod_parent;
873
874 /*
875 * All right, let's create it.
876 */
877 mode = S_IFSOCK |
878 (SOCK_INODE(sock)->i_mode & ~current_umask());
879 err = mnt_want_write(path.mnt);
880 if (err)
881 goto out_mknod_dput;
882 err = security_path_mknod(&path, dentry, mode, 0);
883 if (err)
884 goto out_mknod_drop_write;
885 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
886out_mknod_drop_write:
887 mnt_drop_write(path.mnt);
888 if (err)
889 goto out_mknod_dput;
890 mutex_unlock(&path.dentry->d_inode->i_mutex);
891 dput(path.dentry);
892 path.dentry = dentry;
893
894 addr->hash = UNIX_HASH_SIZE;
895 }
896
897 spin_lock(&unix_table_lock);
898
899 if (!sun_path[0]) {
900 err = -EADDRINUSE;
901 if (__unix_find_socket_byname(net, sunaddr, addr_len,
902 sk->sk_type, hash)) {
903 unix_release_addr(addr);
904 goto out_unlock;
905 }
906
907 list = &unix_socket_table[addr->hash];
908 } else {
909 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
910 u->path = path;
911 }
912
913 err = 0;
914 __unix_remove_socket(sk);
915 u->addr = addr;
916 __unix_insert_socket(list, sk);
917
918out_unlock:
919 spin_unlock(&unix_table_lock);
920out_up:
921 mutex_unlock(&u->readlock);
922out:
923 return err;
924
925out_mknod_dput:
926 dput(dentry);
927 mutex_unlock(&path.dentry->d_inode->i_mutex);
928 path_put(&path);
929out_mknod_parent:
930 if (err == -EEXIST)
931 err = -EADDRINUSE;
932 unix_release_addr(addr);
933 goto out_up;
934}
935
936static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
937{
938 if (unlikely(sk1 == sk2) || !sk2) {
939 unix_state_lock(sk1);
940 return;
941 }
942 if (sk1 < sk2) {
943 unix_state_lock(sk1);
944 unix_state_lock_nested(sk2);
945 } else {
946 unix_state_lock(sk2);
947 unix_state_lock_nested(sk1);
948 }
949}
950
951static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
952{
953 if (unlikely(sk1 == sk2) || !sk2) {
954 unix_state_unlock(sk1);
955 return;
956 }
957 unix_state_unlock(sk1);
958 unix_state_unlock(sk2);
959}
960
961static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
962 int alen, int flags)
963{
964 struct sock *sk = sock->sk;
965 struct net *net = sock_net(sk);
966 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
967 struct sock *other;
968 unsigned int hash;
969 int err;
970
971 if (addr->sa_family != AF_UNSPEC) {
972 err = unix_mkname(sunaddr, alen, &hash);
973 if (err < 0)
974 goto out;
975 alen = err;
976
977 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
978 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
979 goto out;
980
981restart:
982 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
983 if (!other)
984 goto out;
985
986 unix_state_double_lock(sk, other);
987
988 /* Apparently VFS overslept socket death. Retry. */
989 if (sock_flag(other, SOCK_DEAD)) {
990 unix_state_double_unlock(sk, other);
991 sock_put(other);
992 goto restart;
993 }
994
995 err = -EPERM;
996 if (!unix_may_send(sk, other))
997 goto out_unlock;
998
999 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1000 if (err)
1001 goto out_unlock;
1002
1003 } else {
1004 /*
1005 * 1003.1g breaking connected state with AF_UNSPEC
1006 */
1007 other = NULL;
1008 unix_state_double_lock(sk, other);
1009 }
1010
1011 /*
1012 * If it was connected, reconnect.
1013 */
1014 if (unix_peer(sk)) {
1015 struct sock *old_peer = unix_peer(sk);
1016 unix_peer(sk) = other;
1017 unix_state_double_unlock(sk, other);
1018
1019 if (other != old_peer)
1020 unix_dgram_disconnected(sk, old_peer);
1021 sock_put(old_peer);
1022 } else {
1023 unix_peer(sk) = other;
1024 unix_state_double_unlock(sk, other);
1025 }
1026 return 0;
1027
1028out_unlock:
1029 unix_state_double_unlock(sk, other);
1030 sock_put(other);
1031out:
1032 return err;
1033}
1034
1035static long unix_wait_for_peer(struct sock *other, long timeo)
1036{
1037 struct unix_sock *u = unix_sk(other);
1038 int sched;
1039 DEFINE_WAIT(wait);
1040
1041 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1042
1043 sched = !sock_flag(other, SOCK_DEAD) &&
1044 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1045 unix_recvq_full(other);
1046
1047 unix_state_unlock(other);
1048
1049 if (sched)
1050 timeo = schedule_timeout(timeo);
1051
1052 finish_wait(&u->peer_wait, &wait);
1053 return timeo;
1054}
1055
1056static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1057 int addr_len, int flags)
1058{
1059 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1060 struct sock *sk = sock->sk;
1061 struct net *net = sock_net(sk);
1062 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1063 struct sock *newsk = NULL;
1064 struct sock *other = NULL;
1065 struct sk_buff *skb = NULL;
1066 unsigned int hash;
1067 int st;
1068 int err;
1069 long timeo;
1070
1071 err = unix_mkname(sunaddr, addr_len, &hash);
1072 if (err < 0)
1073 goto out;
1074 addr_len = err;
1075
1076 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1077 (err = unix_autobind(sock)) != 0)
1078 goto out;
1079
1080 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1081
1082 /* First of all allocate resources.
1083 If we will make it after state is locked,
1084 we will have to recheck all again in any case.
1085 */
1086
1087 err = -ENOMEM;
1088
1089 /* create new sock for complete connection */
1090 newsk = unix_create1(sock_net(sk), NULL);
1091 if (newsk == NULL)
1092 goto out;
1093
1094 /* Allocate skb for sending to listening sock */
1095 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1096 if (skb == NULL)
1097 goto out;
1098
1099restart:
1100 /* Find listening sock. */
1101 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1102 if (!other)
1103 goto out;
1104
1105 /* Latch state of peer */
1106 unix_state_lock(other);
1107
1108 /* Apparently VFS overslept socket death. Retry. */
1109 if (sock_flag(other, SOCK_DEAD)) {
1110 unix_state_unlock(other);
1111 sock_put(other);
1112 goto restart;
1113 }
1114
1115 err = -ECONNREFUSED;
1116 if (other->sk_state != TCP_LISTEN)
1117 goto out_unlock;
1118 if (other->sk_shutdown & RCV_SHUTDOWN)
1119 goto out_unlock;
1120
1121 if (unix_recvq_full(other)) {
1122 err = -EAGAIN;
1123 if (!timeo)
1124 goto out_unlock;
1125
1126 timeo = unix_wait_for_peer(other, timeo);
1127
1128 err = sock_intr_errno(timeo);
1129 if (signal_pending(current))
1130 goto out;
1131 sock_put(other);
1132 goto restart;
1133 }
1134
1135 /* Latch our state.
1136
1137 It is tricky place. We need to grab our state lock and cannot
1138 drop lock on peer. It is dangerous because deadlock is
1139 possible. Connect to self case and simultaneous
1140 attempt to connect are eliminated by checking socket
1141 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1142 check this before attempt to grab lock.
1143
1144 Well, and we have to recheck the state after socket locked.
1145 */
1146 st = sk->sk_state;
1147
1148 switch (st) {
1149 case TCP_CLOSE:
1150 /* This is ok... continue with connect */
1151 break;
1152 case TCP_ESTABLISHED:
1153 /* Socket is already connected */
1154 err = -EISCONN;
1155 goto out_unlock;
1156 default:
1157 err = -EINVAL;
1158 goto out_unlock;
1159 }
1160
1161 unix_state_lock_nested(sk);
1162
1163 if (sk->sk_state != st) {
1164 unix_state_unlock(sk);
1165 unix_state_unlock(other);
1166 sock_put(other);
1167 goto restart;
1168 }
1169
1170 err = security_unix_stream_connect(sk, other, newsk);
1171 if (err) {
1172 unix_state_unlock(sk);
1173 goto out_unlock;
1174 }
1175
1176 /* The way is open! Fastly set all the necessary fields... */
1177
1178 sock_hold(sk);
1179 unix_peer(newsk) = sk;
1180 newsk->sk_state = TCP_ESTABLISHED;
1181 newsk->sk_type = sk->sk_type;
1182 init_peercred(newsk);
1183 newu = unix_sk(newsk);
1184 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1185 otheru = unix_sk(other);
1186
1187 /* copy address information from listening to new sock*/
1188 if (otheru->addr) {
1189 atomic_inc(&otheru->addr->refcnt);
1190 newu->addr = otheru->addr;
1191 }
1192 if (otheru->path.dentry) {
1193 path_get(&otheru->path);
1194 newu->path = otheru->path;
1195 }
1196
1197 /* Set credentials */
1198 copy_peercred(sk, other);
1199
1200 sock->state = SS_CONNECTED;
1201 sk->sk_state = TCP_ESTABLISHED;
1202 sock_hold(newsk);
1203
1204 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1205 unix_peer(sk) = newsk;
1206
1207 unix_state_unlock(sk);
1208
1209 /* take ten and and send info to listening sock */
1210 spin_lock(&other->sk_receive_queue.lock);
1211 __skb_queue_tail(&other->sk_receive_queue, skb);
1212 spin_unlock(&other->sk_receive_queue.lock);
1213 unix_state_unlock(other);
1214 other->sk_data_ready(other, 0);
1215 sock_put(other);
1216 return 0;
1217
1218out_unlock:
1219 if (other)
1220 unix_state_unlock(other);
1221
1222out:
1223 kfree_skb(skb);
1224 if (newsk)
1225 unix_release_sock(newsk, 0);
1226 if (other)
1227 sock_put(other);
1228 return err;
1229}
1230
1231static int unix_socketpair(struct socket *socka, struct socket *sockb)
1232{
1233 struct sock *ska = socka->sk, *skb = sockb->sk;
1234
1235 /* Join our sockets back to back */
1236 sock_hold(ska);
1237 sock_hold(skb);
1238 unix_peer(ska) = skb;
1239 unix_peer(skb) = ska;
1240 init_peercred(ska);
1241 init_peercred(skb);
1242
1243 if (ska->sk_type != SOCK_DGRAM) {
1244 ska->sk_state = TCP_ESTABLISHED;
1245 skb->sk_state = TCP_ESTABLISHED;
1246 socka->state = SS_CONNECTED;
1247 sockb->state = SS_CONNECTED;
1248 }
1249 return 0;
1250}
1251
1252static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1253{
1254 struct sock *sk = sock->sk;
1255 struct sock *tsk;
1256 struct sk_buff *skb;
1257 int err;
1258
1259 err = -EOPNOTSUPP;
1260 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1261 goto out;
1262
1263 err = -EINVAL;
1264 if (sk->sk_state != TCP_LISTEN)
1265 goto out;
1266
1267 /* If socket state is TCP_LISTEN it cannot change (for now...),
1268 * so that no locks are necessary.
1269 */
1270
1271 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1272 if (!skb) {
1273 /* This means receive shutdown. */
1274 if (err == 0)
1275 err = -EINVAL;
1276 goto out;
1277 }
1278
1279 tsk = skb->sk;
1280 skb_free_datagram(sk, skb);
1281 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1282
1283 /* attach accepted sock to socket */
1284 unix_state_lock(tsk);
1285 newsock->state = SS_CONNECTED;
1286 sock_graft(tsk, newsock);
1287 unix_state_unlock(tsk);
1288 return 0;
1289
1290out:
1291 return err;
1292}
1293
1294
1295static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1296{
1297 struct sock *sk = sock->sk;
1298 struct unix_sock *u;
1299 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1300 int err = 0;
1301
1302 if (peer) {
1303 sk = unix_peer_get(sk);
1304
1305 err = -ENOTCONN;
1306 if (!sk)
1307 goto out;
1308 err = 0;
1309 } else {
1310 sock_hold(sk);
1311 }
1312
1313 u = unix_sk(sk);
1314 unix_state_lock(sk);
1315 if (!u->addr) {
1316 sunaddr->sun_family = AF_UNIX;
1317 sunaddr->sun_path[0] = 0;
1318 *uaddr_len = sizeof(short);
1319 } else {
1320 struct unix_address *addr = u->addr;
1321
1322 *uaddr_len = addr->len;
1323 memcpy(sunaddr, addr->name, *uaddr_len);
1324 }
1325 unix_state_unlock(sk);
1326 sock_put(sk);
1327out:
1328 return err;
1329}
1330
1331static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1332{
1333 int i;
1334
1335 scm->fp = UNIXCB(skb).fp;
1336 UNIXCB(skb).fp = NULL;
1337
1338 for (i = scm->fp->count-1; i >= 0; i--)
1339 unix_notinflight(scm->fp->fp[i]);
1340}
1341
1342static void unix_destruct_scm(struct sk_buff *skb)
1343{
1344 struct scm_cookie scm;
1345 memset(&scm, 0, sizeof(scm));
1346 scm.pid = UNIXCB(skb).pid;
1347 scm.cred = UNIXCB(skb).cred;
1348 if (UNIXCB(skb).fp)
1349 unix_detach_fds(&scm, skb);
1350
1351 /* Alas, it calls VFS */
1352 /* So fscking what? fput() had been SMP-safe since the last Summer */
1353 scm_destroy(&scm);
1354 sock_wfree(skb);
1355}
1356
1357#define MAX_RECURSION_LEVEL 4
1358
1359static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1360{
1361 int i;
1362 unsigned char max_level = 0;
1363 int unix_sock_count = 0;
1364
1365 for (i = scm->fp->count - 1; i >= 0; i--) {
1366 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1367
1368 if (sk) {
1369 unix_sock_count++;
1370 max_level = max(max_level,
1371 unix_sk(sk)->recursion_level);
1372 }
1373 }
1374 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1375 return -ETOOMANYREFS;
1376
1377 /*
1378 * Need to duplicate file references for the sake of garbage
1379 * collection. Otherwise a socket in the fps might become a
1380 * candidate for GC while the skb is not yet queued.
1381 */
1382 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1383 if (!UNIXCB(skb).fp)
1384 return -ENOMEM;
1385
1386 if (unix_sock_count) {
1387 for (i = scm->fp->count - 1; i >= 0; i--)
1388 unix_inflight(scm->fp->fp[i]);
1389 }
1390 return max_level;
1391}
1392
1393static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1394{
1395 int err = 0;
1396
1397 UNIXCB(skb).pid = get_pid(scm->pid);
1398 if (scm->cred)
1399 UNIXCB(skb).cred = get_cred(scm->cred);
1400 UNIXCB(skb).fp = NULL;
1401 if (scm->fp && send_fds)
1402 err = unix_attach_fds(scm, skb);
1403
1404 skb->destructor = unix_destruct_scm;
1405 return err;
1406}
1407
1408/*
1409 * Some apps rely on write() giving SCM_CREDENTIALS
1410 * We include credentials if source or destination socket
1411 * asserted SOCK_PASSCRED.
1412 */
1413static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1414 const struct sock *other)
1415{
1416 if (UNIXCB(skb).cred)
1417 return;
1418 if (test_bit(SOCK_PASSCRED, &sock->flags) ||
1419 !other->sk_socket ||
1420 test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
1421 UNIXCB(skb).pid = get_pid(task_tgid(current));
1422 UNIXCB(skb).cred = get_current_cred();
1423 }
1424}
1425
1426/*
1427 * Send AF_UNIX data.
1428 */
1429
1430static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1431 struct msghdr *msg, size_t len)
1432{
1433 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1434 struct sock *sk = sock->sk;
1435 struct net *net = sock_net(sk);
1436 struct unix_sock *u = unix_sk(sk);
1437 struct sockaddr_un *sunaddr = msg->msg_name;
1438 struct sock *other = NULL;
1439 int namelen = 0; /* fake GCC */
1440 int err;
1441 unsigned int hash;
1442 struct sk_buff *skb;
1443 long timeo;
1444 struct scm_cookie tmp_scm;
1445 int max_level;
1446 int data_len = 0;
1447
1448 if (NULL == siocb->scm)
1449 siocb->scm = &tmp_scm;
1450 wait_for_unix_gc();
1451 err = scm_send(sock, msg, siocb->scm, false);
1452 if (err < 0)
1453 return err;
1454
1455 err = -EOPNOTSUPP;
1456 if (msg->msg_flags&MSG_OOB)
1457 goto out;
1458
1459 if (msg->msg_namelen) {
1460 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1461 if (err < 0)
1462 goto out;
1463 namelen = err;
1464 } else {
1465 sunaddr = NULL;
1466 err = -ENOTCONN;
1467 other = unix_peer_get(sk);
1468 if (!other)
1469 goto out;
1470 }
1471
1472 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1473 && (err = unix_autobind(sock)) != 0)
1474 goto out;
1475
1476 err = -EMSGSIZE;
1477 if (len > sk->sk_sndbuf - 32)
1478 goto out;
1479
1480 if (len > SKB_MAX_ALLOC)
1481 data_len = min_t(size_t,
1482 len - SKB_MAX_ALLOC,
1483 MAX_SKB_FRAGS * PAGE_SIZE);
1484
1485 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1486 msg->msg_flags & MSG_DONTWAIT, &err);
1487 if (skb == NULL)
1488 goto out;
1489
1490 err = unix_scm_to_skb(siocb->scm, skb, true);
1491 if (err < 0)
1492 goto out_free;
1493 max_level = err + 1;
1494 unix_get_secdata(siocb->scm, skb);
1495
1496 skb_put(skb, len - data_len);
1497 skb->data_len = data_len;
1498 skb->len = len;
1499 err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 0, len);
1500 if (err)
1501 goto out_free;
1502
1503 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1504
1505restart:
1506 if (!other) {
1507 err = -ECONNRESET;
1508 if (sunaddr == NULL)
1509 goto out_free;
1510
1511 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1512 hash, &err);
1513 if (other == NULL)
1514 goto out_free;
1515 }
1516
1517 if (sk_filter(other, skb) < 0) {
1518 /* Toss the packet but do not return any error to the sender */
1519 err = len;
1520 goto out_free;
1521 }
1522
1523 unix_state_lock(other);
1524 err = -EPERM;
1525 if (!unix_may_send(sk, other))
1526 goto out_unlock;
1527
1528 if (sock_flag(other, SOCK_DEAD)) {
1529 /*
1530 * Check with 1003.1g - what should
1531 * datagram error
1532 */
1533 unix_state_unlock(other);
1534 sock_put(other);
1535
1536 err = 0;
1537 unix_state_lock(sk);
1538 if (unix_peer(sk) == other) {
1539 unix_peer(sk) = NULL;
1540 unix_state_unlock(sk);
1541
1542 unix_dgram_disconnected(sk, other);
1543 sock_put(other);
1544 err = -ECONNREFUSED;
1545 } else {
1546 unix_state_unlock(sk);
1547 }
1548
1549 other = NULL;
1550 if (err)
1551 goto out_free;
1552 goto restart;
1553 }
1554
1555 err = -EPIPE;
1556 if (other->sk_shutdown & RCV_SHUTDOWN)
1557 goto out_unlock;
1558
1559 if (sk->sk_type != SOCK_SEQPACKET) {
1560 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1561 if (err)
1562 goto out_unlock;
1563 }
1564
1565 if (unix_peer(other) != sk && unix_recvq_full(other)) {
1566 if (!timeo) {
1567 err = -EAGAIN;
1568 goto out_unlock;
1569 }
1570
1571 timeo = unix_wait_for_peer(other, timeo);
1572
1573 err = sock_intr_errno(timeo);
1574 if (signal_pending(current))
1575 goto out_free;
1576
1577 goto restart;
1578 }
1579
1580 if (sock_flag(other, SOCK_RCVTSTAMP))
1581 __net_timestamp(skb);
1582 maybe_add_creds(skb, sock, other);
1583 skb_queue_tail(&other->sk_receive_queue, skb);
1584 if (max_level > unix_sk(other)->recursion_level)
1585 unix_sk(other)->recursion_level = max_level;
1586 unix_state_unlock(other);
1587 other->sk_data_ready(other, len);
1588 sock_put(other);
1589 scm_destroy(siocb->scm);
1590 return len;
1591
1592out_unlock:
1593 unix_state_unlock(other);
1594out_free:
1595 kfree_skb(skb);
1596out:
1597 if (other)
1598 sock_put(other);
1599 scm_destroy(siocb->scm);
1600 return err;
1601}
1602
1603
1604static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1605 struct msghdr *msg, size_t len)
1606{
1607 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1608 struct sock *sk = sock->sk;
1609 struct sock *other = NULL;
1610 int err, size;
1611 struct sk_buff *skb;
1612 int sent = 0;
1613 struct scm_cookie tmp_scm;
1614 bool fds_sent = false;
1615 int max_level;
1616
1617 if (NULL == siocb->scm)
1618 siocb->scm = &tmp_scm;
1619 wait_for_unix_gc();
1620 err = scm_send(sock, msg, siocb->scm, false);
1621 if (err < 0)
1622 return err;
1623
1624 err = -EOPNOTSUPP;
1625 if (msg->msg_flags&MSG_OOB)
1626 goto out_err;
1627
1628 if (msg->msg_namelen) {
1629 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1630 goto out_err;
1631 } else {
1632 err = -ENOTCONN;
1633 other = unix_peer(sk);
1634 if (!other)
1635 goto out_err;
1636 }
1637
1638 if (sk->sk_shutdown & SEND_SHUTDOWN)
1639 goto pipe_err;
1640
1641 while (sent < len) {
1642 /*
1643 * Optimisation for the fact that under 0.01% of X
1644 * messages typically need breaking up.
1645 */
1646
1647 size = len-sent;
1648
1649 /* Keep two messages in the pipe so it schedules better */
1650 if (size > ((sk->sk_sndbuf >> 1) - 64))
1651 size = (sk->sk_sndbuf >> 1) - 64;
1652
1653 if (size > SKB_MAX_ALLOC)
1654 size = SKB_MAX_ALLOC;
1655
1656 /*
1657 * Grab a buffer
1658 */
1659
1660 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1661 &err);
1662
1663 if (skb == NULL)
1664 goto out_err;
1665
1666 /*
1667 * If you pass two values to the sock_alloc_send_skb
1668 * it tries to grab the large buffer with GFP_NOFS
1669 * (which can fail easily), and if it fails grab the
1670 * fallback size buffer which is under a page and will
1671 * succeed. [Alan]
1672 */
1673 size = min_t(int, size, skb_tailroom(skb));
1674
1675
1676 /* Only send the fds in the first buffer */
1677 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1678 if (err < 0) {
1679 kfree_skb(skb);
1680 goto out_err;
1681 }
1682 max_level = err + 1;
1683 fds_sent = true;
1684
1685 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1686 if (err) {
1687 kfree_skb(skb);
1688 goto out_err;
1689 }
1690
1691 unix_state_lock(other);
1692
1693 if (sock_flag(other, SOCK_DEAD) ||
1694 (other->sk_shutdown & RCV_SHUTDOWN))
1695 goto pipe_err_free;
1696
1697 maybe_add_creds(skb, sock, other);
1698 skb_queue_tail(&other->sk_receive_queue, skb);
1699 if (max_level > unix_sk(other)->recursion_level)
1700 unix_sk(other)->recursion_level = max_level;
1701 unix_state_unlock(other);
1702 other->sk_data_ready(other, size);
1703 sent += size;
1704 }
1705
1706 scm_destroy(siocb->scm);
1707 siocb->scm = NULL;
1708
1709 return sent;
1710
1711pipe_err_free:
1712 unix_state_unlock(other);
1713 kfree_skb(skb);
1714pipe_err:
1715 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1716 send_sig(SIGPIPE, current, 0);
1717 err = -EPIPE;
1718out_err:
1719 scm_destroy(siocb->scm);
1720 siocb->scm = NULL;
1721 return sent ? : err;
1722}
1723
1724static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1725 struct msghdr *msg, size_t len)
1726{
1727 int err;
1728 struct sock *sk = sock->sk;
1729
1730 err = sock_error(sk);
1731 if (err)
1732 return err;
1733
1734 if (sk->sk_state != TCP_ESTABLISHED)
1735 return -ENOTCONN;
1736
1737 if (msg->msg_namelen)
1738 msg->msg_namelen = 0;
1739
1740 return unix_dgram_sendmsg(kiocb, sock, msg, len);
1741}
1742
1743static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
1744 struct msghdr *msg, size_t size,
1745 int flags)
1746{
1747 struct sock *sk = sock->sk;
1748
1749 if (sk->sk_state != TCP_ESTABLISHED)
1750 return -ENOTCONN;
1751
1752 return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
1753}
1754
1755static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1756{
1757 struct unix_sock *u = unix_sk(sk);
1758
1759 msg->msg_namelen = 0;
1760 if (u->addr) {
1761 msg->msg_namelen = u->addr->len;
1762 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1763 }
1764}
1765
1766static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1767 struct msghdr *msg, size_t size,
1768 int flags)
1769{
1770 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1771 struct scm_cookie tmp_scm;
1772 struct sock *sk = sock->sk;
1773 struct unix_sock *u = unix_sk(sk);
1774 int noblock = flags & MSG_DONTWAIT;
1775 struct sk_buff *skb;
1776 int err;
1777 int peeked, skip;
1778
1779 err = -EOPNOTSUPP;
1780 if (flags&MSG_OOB)
1781 goto out;
1782
1783 msg->msg_namelen = 0;
1784
1785 err = mutex_lock_interruptible(&u->readlock);
1786 if (err) {
1787 err = sock_intr_errno(sock_rcvtimeo(sk, noblock));
1788 goto out;
1789 }
1790
1791 skip = sk_peek_offset(sk, flags);
1792
1793 skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err);
1794 if (!skb) {
1795 unix_state_lock(sk);
1796 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1797 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1798 (sk->sk_shutdown & RCV_SHUTDOWN))
1799 err = 0;
1800 unix_state_unlock(sk);
1801 goto out_unlock;
1802 }
1803
1804 wake_up_interruptible_sync_poll(&u->peer_wait,
1805 POLLOUT | POLLWRNORM | POLLWRBAND);
1806
1807 if (msg->msg_name)
1808 unix_copy_addr(msg, skb->sk);
1809
1810 if (size > skb->len - skip)
1811 size = skb->len - skip;
1812 else if (size < skb->len - skip)
1813 msg->msg_flags |= MSG_TRUNC;
1814
1815 err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size);
1816 if (err)
1817 goto out_free;
1818
1819 if (sock_flag(sk, SOCK_RCVTSTAMP))
1820 __sock_recv_timestamp(msg, sk, skb);
1821
1822 if (!siocb->scm) {
1823 siocb->scm = &tmp_scm;
1824 memset(&tmp_scm, 0, sizeof(tmp_scm));
1825 }
1826 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1827 unix_set_secdata(siocb->scm, skb);
1828
1829 if (!(flags & MSG_PEEK)) {
1830 if (UNIXCB(skb).fp)
1831 unix_detach_fds(siocb->scm, skb);
1832
1833 sk_peek_offset_bwd(sk, skb->len);
1834 } else {
1835 /* It is questionable: on PEEK we could:
1836 - do not return fds - good, but too simple 8)
1837 - return fds, and do not return them on read (old strategy,
1838 apparently wrong)
1839 - clone fds (I chose it for now, it is the most universal
1840 solution)
1841
1842 POSIX 1003.1g does not actually define this clearly
1843 at all. POSIX 1003.1g doesn't define a lot of things
1844 clearly however!
1845
1846 */
1847
1848 sk_peek_offset_fwd(sk, size);
1849
1850 if (UNIXCB(skb).fp)
1851 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1852 }
1853 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
1854
1855 scm_recv(sock, msg, siocb->scm, flags);
1856
1857out_free:
1858 skb_free_datagram(sk, skb);
1859out_unlock:
1860 mutex_unlock(&u->readlock);
1861out:
1862 return err;
1863}
1864
1865/*
1866 * Sleep until data has arrive. But check for races..
1867 */
1868
1869static long unix_stream_data_wait(struct sock *sk, long timeo)
1870{
1871 DEFINE_WAIT(wait);
1872
1873 unix_state_lock(sk);
1874
1875 for (;;) {
1876 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1877
1878 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1879 sk->sk_err ||
1880 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1881 signal_pending(current) ||
1882 !timeo)
1883 break;
1884
1885 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1886 unix_state_unlock(sk);
1887 timeo = schedule_timeout(timeo);
1888 unix_state_lock(sk);
1889 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1890 }
1891
1892 finish_wait(sk_sleep(sk), &wait);
1893 unix_state_unlock(sk);
1894 return timeo;
1895}
1896
1897
1898
1899static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1900 struct msghdr *msg, size_t size,
1901 int flags)
1902{
1903 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1904 struct scm_cookie tmp_scm;
1905 struct sock *sk = sock->sk;
1906 struct unix_sock *u = unix_sk(sk);
1907 struct sockaddr_un *sunaddr = msg->msg_name;
1908 int copied = 0;
1909 int check_creds = 0;
1910 int target;
1911 int err = 0;
1912 long timeo;
1913 int skip;
1914
1915 err = -EINVAL;
1916 if (sk->sk_state != TCP_ESTABLISHED)
1917 goto out;
1918
1919 err = -EOPNOTSUPP;
1920 if (flags&MSG_OOB)
1921 goto out;
1922
1923 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1924 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1925
1926 msg->msg_namelen = 0;
1927
1928 /* Lock the socket to prevent queue disordering
1929 * while sleeps in memcpy_tomsg
1930 */
1931
1932 if (!siocb->scm) {
1933 siocb->scm = &tmp_scm;
1934 memset(&tmp_scm, 0, sizeof(tmp_scm));
1935 }
1936
1937 err = mutex_lock_interruptible(&u->readlock);
1938 if (err) {
1939 err = sock_intr_errno(timeo);
1940 goto out;
1941 }
1942
1943 skip = sk_peek_offset(sk, flags);
1944
1945 do {
1946 int chunk;
1947 struct sk_buff *skb;
1948
1949 unix_state_lock(sk);
1950 skb = skb_peek(&sk->sk_receive_queue);
1951again:
1952 if (skb == NULL) {
1953 unix_sk(sk)->recursion_level = 0;
1954 if (copied >= target)
1955 goto unlock;
1956
1957 /*
1958 * POSIX 1003.1g mandates this order.
1959 */
1960
1961 err = sock_error(sk);
1962 if (err)
1963 goto unlock;
1964 if (sk->sk_shutdown & RCV_SHUTDOWN)
1965 goto unlock;
1966
1967 unix_state_unlock(sk);
1968 err = -EAGAIN;
1969 if (!timeo)
1970 break;
1971 mutex_unlock(&u->readlock);
1972
1973 timeo = unix_stream_data_wait(sk, timeo);
1974
1975 if (signal_pending(current)
1976 || mutex_lock_interruptible(&u->readlock)) {
1977 err = sock_intr_errno(timeo);
1978 goto out;
1979 }
1980
1981 continue;
1982 unlock:
1983 unix_state_unlock(sk);
1984 break;
1985 }
1986
1987 if (skip >= skb->len) {
1988 skip -= skb->len;
1989 skb = skb_peek_next(skb, &sk->sk_receive_queue);
1990 goto again;
1991 }
1992
1993 unix_state_unlock(sk);
1994
1995 if (check_creds) {
1996 /* Never glue messages from different writers */
1997 if ((UNIXCB(skb).pid != siocb->scm->pid) ||
1998 (UNIXCB(skb).cred != siocb->scm->cred))
1999 break;
2000 } else {
2001 /* Copy credentials */
2002 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
2003 check_creds = 1;
2004 }
2005
2006 /* Copy address just once */
2007 if (sunaddr) {
2008 unix_copy_addr(msg, skb->sk);
2009 sunaddr = NULL;
2010 }
2011
2012 chunk = min_t(unsigned int, skb->len - skip, size);
2013 if (memcpy_toiovec(msg->msg_iov, skb->data + skip, chunk)) {
2014 if (copied == 0)
2015 copied = -EFAULT;
2016 break;
2017 }
2018 copied += chunk;
2019 size -= chunk;
2020
2021 /* Mark read part of skb as used */
2022 if (!(flags & MSG_PEEK)) {
2023 skb_pull(skb, chunk);
2024
2025 sk_peek_offset_bwd(sk, chunk);
2026
2027 if (UNIXCB(skb).fp)
2028 unix_detach_fds(siocb->scm, skb);
2029
2030 if (skb->len)
2031 break;
2032
2033 skb_unlink(skb, &sk->sk_receive_queue);
2034 consume_skb(skb);
2035
2036 if (siocb->scm->fp)
2037 break;
2038 } else {
2039 /* It is questionable, see note in unix_dgram_recvmsg.
2040 */
2041 if (UNIXCB(skb).fp)
2042 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
2043
2044 sk_peek_offset_fwd(sk, chunk);
2045
2046 break;
2047 }
2048 } while (size);
2049
2050 mutex_unlock(&u->readlock);
2051 scm_recv(sock, msg, siocb->scm, flags);
2052out:
2053 return copied ? : err;
2054}
2055
2056static int unix_shutdown(struct socket *sock, int mode)
2057{
2058 struct sock *sk = sock->sk;
2059 struct sock *other;
2060
2061 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
2062
2063 if (!mode)
2064 return 0;
2065
2066 unix_state_lock(sk);
2067 sk->sk_shutdown |= mode;
2068 other = unix_peer(sk);
2069 if (other)
2070 sock_hold(other);
2071 unix_state_unlock(sk);
2072 sk->sk_state_change(sk);
2073
2074 if (other &&
2075 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2076
2077 int peer_mode = 0;
2078
2079 if (mode&RCV_SHUTDOWN)
2080 peer_mode |= SEND_SHUTDOWN;
2081 if (mode&SEND_SHUTDOWN)
2082 peer_mode |= RCV_SHUTDOWN;
2083 unix_state_lock(other);
2084 other->sk_shutdown |= peer_mode;
2085 unix_state_unlock(other);
2086 other->sk_state_change(other);
2087 if (peer_mode == SHUTDOWN_MASK)
2088 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2089 else if (peer_mode & RCV_SHUTDOWN)
2090 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2091 }
2092 if (other)
2093 sock_put(other);
2094
2095 return 0;
2096}
2097
2098long unix_inq_len(struct sock *sk)
2099{
2100 struct sk_buff *skb;
2101 long amount = 0;
2102
2103 if (sk->sk_state == TCP_LISTEN)
2104 return -EINVAL;
2105
2106 spin_lock(&sk->sk_receive_queue.lock);
2107 if (sk->sk_type == SOCK_STREAM ||
2108 sk->sk_type == SOCK_SEQPACKET) {
2109 skb_queue_walk(&sk->sk_receive_queue, skb)
2110 amount += skb->len;
2111 } else {
2112 skb = skb_peek(&sk->sk_receive_queue);
2113 if (skb)
2114 amount = skb->len;
2115 }
2116 spin_unlock(&sk->sk_receive_queue.lock);
2117
2118 return amount;
2119}
2120EXPORT_SYMBOL_GPL(unix_inq_len);
2121
2122long unix_outq_len(struct sock *sk)
2123{
2124 return sk_wmem_alloc_get(sk);
2125}
2126EXPORT_SYMBOL_GPL(unix_outq_len);
2127
2128static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2129{
2130 struct sock *sk = sock->sk;
2131 long amount = 0;
2132 int err;
2133
2134 switch (cmd) {
2135 case SIOCOUTQ:
2136 amount = unix_outq_len(sk);
2137 err = put_user(amount, (int __user *)arg);
2138 break;
2139 case SIOCINQ:
2140 amount = unix_inq_len(sk);
2141 if (amount < 0)
2142 err = amount;
2143 else
2144 err = put_user(amount, (int __user *)arg);
2145 break;
2146 default:
2147 err = -ENOIOCTLCMD;
2148 break;
2149 }
2150 return err;
2151}
2152
2153static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2154{
2155 struct sock *sk = sock->sk;
2156 unsigned int mask;
2157
2158 sock_poll_wait(file, sk_sleep(sk), wait);
2159 mask = 0;
2160
2161 /* exceptional events? */
2162 if (sk->sk_err)
2163 mask |= POLLERR;
2164 if (sk->sk_shutdown == SHUTDOWN_MASK)
2165 mask |= POLLHUP;
2166 if (sk->sk_shutdown & RCV_SHUTDOWN)
2167 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2168
2169 /* readable? */
2170 if (!skb_queue_empty(&sk->sk_receive_queue))
2171 mask |= POLLIN | POLLRDNORM;
2172
2173 /* Connection-based need to check for termination and startup */
2174 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2175 sk->sk_state == TCP_CLOSE)
2176 mask |= POLLHUP;
2177
2178 /*
2179 * we set writable also when the other side has shut down the
2180 * connection. This prevents stuck sockets.
2181 */
2182 if (unix_writable(sk))
2183 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2184
2185 return mask;
2186}
2187
2188static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2189 poll_table *wait)
2190{
2191 struct sock *sk = sock->sk, *other;
2192 unsigned int mask, writable;
2193
2194 sock_poll_wait(file, sk_sleep(sk), wait);
2195 mask = 0;
2196
2197 /* exceptional events? */
2198 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2199 mask |= POLLERR;
2200 if (sk->sk_shutdown & RCV_SHUTDOWN)
2201 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2202 if (sk->sk_shutdown == SHUTDOWN_MASK)
2203 mask |= POLLHUP;
2204
2205 /* readable? */
2206 if (!skb_queue_empty(&sk->sk_receive_queue))
2207 mask |= POLLIN | POLLRDNORM;
2208
2209 /* Connection-based need to check for termination and startup */
2210 if (sk->sk_type == SOCK_SEQPACKET) {
2211 if (sk->sk_state == TCP_CLOSE)
2212 mask |= POLLHUP;
2213 /* connection hasn't started yet? */
2214 if (sk->sk_state == TCP_SYN_SENT)
2215 return mask;
2216 }
2217
2218 /* No write status requested, avoid expensive OUT tests. */
2219 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
2220 return mask;
2221
2222 writable = unix_writable(sk);
2223 other = unix_peer_get(sk);
2224 if (other) {
2225 if (unix_peer(other) != sk) {
2226 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
2227 if (unix_recvq_full(other))
2228 writable = 0;
2229 }
2230 sock_put(other);
2231 }
2232
2233 if (writable)
2234 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2235 else
2236 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2237
2238 return mask;
2239}
2240
2241#ifdef CONFIG_PROC_FS
2242static struct sock *first_unix_socket(int *i)
2243{
2244 for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2245 if (!hlist_empty(&unix_socket_table[*i]))
2246 return __sk_head(&unix_socket_table[*i]);
2247 }
2248 return NULL;
2249}
2250
2251static struct sock *next_unix_socket(int *i, struct sock *s)
2252{
2253 struct sock *next = sk_next(s);
2254 /* More in this chain? */
2255 if (next)
2256 return next;
2257 /* Look for next non-empty chain. */
2258 for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2259 if (!hlist_empty(&unix_socket_table[*i]))
2260 return __sk_head(&unix_socket_table[*i]);
2261 }
2262 return NULL;
2263}
2264
2265struct unix_iter_state {
2266 struct seq_net_private p;
2267 int i;
2268};
2269
2270static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2271{
2272 struct unix_iter_state *iter = seq->private;
2273 loff_t off = 0;
2274 struct sock *s;
2275
2276 for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2277 if (sock_net(s) != seq_file_net(seq))
2278 continue;
2279 if (off == pos)
2280 return s;
2281 ++off;
2282 }
2283 return NULL;
2284}
2285
2286static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2287 __acquires(unix_table_lock)
2288{
2289 spin_lock(&unix_table_lock);
2290 return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2291}
2292
2293static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2294{
2295 struct unix_iter_state *iter = seq->private;
2296 struct sock *sk = v;
2297 ++*pos;
2298
2299 if (v == SEQ_START_TOKEN)
2300 sk = first_unix_socket(&iter->i);
2301 else
2302 sk = next_unix_socket(&iter->i, sk);
2303 while (sk && (sock_net(sk) != seq_file_net(seq)))
2304 sk = next_unix_socket(&iter->i, sk);
2305 return sk;
2306}
2307
2308static void unix_seq_stop(struct seq_file *seq, void *v)
2309 __releases(unix_table_lock)
2310{
2311 spin_unlock(&unix_table_lock);
2312}
2313
2314static int unix_seq_show(struct seq_file *seq, void *v)
2315{
2316
2317 if (v == SEQ_START_TOKEN)
2318 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2319 "Inode Path\n");
2320 else {
2321 struct sock *s = v;
2322 struct unix_sock *u = unix_sk(s);
2323 unix_state_lock(s);
2324
2325 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2326 s,
2327 atomic_read(&s->sk_refcnt),
2328 0,
2329 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2330 s->sk_type,
2331 s->sk_socket ?
2332 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2333 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2334 sock_i_ino(s));
2335
2336 if (u->addr) {
2337 int i, len;
2338 seq_putc(seq, ' ');
2339
2340 i = 0;
2341 len = u->addr->len - sizeof(short);
2342 if (!UNIX_ABSTRACT(s))
2343 len--;
2344 else {
2345 seq_putc(seq, '@');
2346 i++;
2347 }
2348 for ( ; i < len; i++)
2349 seq_putc(seq, u->addr->name->sun_path[i]);
2350 }
2351 unix_state_unlock(s);
2352 seq_putc(seq, '\n');
2353 }
2354
2355 return 0;
2356}
2357
2358static const struct seq_operations unix_seq_ops = {
2359 .start = unix_seq_start,
2360 .next = unix_seq_next,
2361 .stop = unix_seq_stop,
2362 .show = unix_seq_show,
2363};
2364
2365static int unix_seq_open(struct inode *inode, struct file *file)
2366{
2367 return seq_open_net(inode, file, &unix_seq_ops,
2368 sizeof(struct unix_iter_state));
2369}
2370
2371static const struct file_operations unix_seq_fops = {
2372 .owner = THIS_MODULE,
2373 .open = unix_seq_open,
2374 .read = seq_read,
2375 .llseek = seq_lseek,
2376 .release = seq_release_net,
2377};
2378
2379#endif
2380
2381static const struct net_proto_family unix_family_ops = {
2382 .family = PF_UNIX,
2383 .create = unix_create,
2384 .owner = THIS_MODULE,
2385};
2386
2387
2388static int __net_init unix_net_init(struct net *net)
2389{
2390 int error = -ENOMEM;
2391
2392 net->unx.sysctl_max_dgram_qlen = 10;
2393 if (unix_sysctl_register(net))
2394 goto out;
2395
2396#ifdef CONFIG_PROC_FS
2397 if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2398 unix_sysctl_unregister(net);
2399 goto out;
2400 }
2401#endif
2402 error = 0;
2403out:
2404 return error;
2405}
2406
2407static void __net_exit unix_net_exit(struct net *net)
2408{
2409 unix_sysctl_unregister(net);
2410 proc_net_remove(net, "unix");
2411}
2412
2413static struct pernet_operations unix_net_ops = {
2414 .init = unix_net_init,
2415 .exit = unix_net_exit,
2416};
2417
2418static int __init af_unix_init(void)
2419{
2420 int rc = -1;
2421 struct sk_buff *dummy_skb;
2422
2423 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2424
2425 rc = proto_register(&unix_proto, 1);
2426 if (rc != 0) {
2427 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2428 __func__);
2429 goto out;
2430 }
2431
2432 sock_register(&unix_family_ops);
2433 register_pernet_subsys(&unix_net_ops);
2434out:
2435 return rc;
2436}
2437
2438static void __exit af_unix_exit(void)
2439{
2440 sock_unregister(PF_UNIX);
2441 proto_unregister(&unix_proto);
2442 unregister_pernet_subsys(&unix_net_ops);
2443}
2444
2445/* Earlier than device_initcall() so that other drivers invoking
2446 request_module() don't end up in a loop when modprobe tries
2447 to use a UNIX socket. But later than subsys_initcall() because
2448 we depend on stuff initialised there */
2449fs_initcall(af_unix_init);
2450module_exit(af_unix_exit);
2451
2452MODULE_LICENSE("GPL");
2453MODULE_ALIAS_NETPROTO(PF_UNIX);