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