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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * NET4: Implementation of BSD Unix domain sockets.
4 *
5 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
6 *
7 * Fixes:
8 * Linus Torvalds : Assorted bug cures.
9 * Niibe Yutaka : async I/O support.
10 * Carsten Paeth : PF_UNIX check, address fixes.
11 * Alan Cox : Limit size of allocated blocks.
12 * Alan Cox : Fixed the stupid socketpair bug.
13 * Alan Cox : BSD compatibility fine tuning.
14 * Alan Cox : Fixed a bug in connect when interrupted.
15 * Alan Cox : Sorted out a proper draft version of
16 * file descriptor passing hacked up from
17 * Mike Shaver's work.
18 * Marty Leisner : Fixes to fd passing
19 * Nick Nevin : recvmsg bugfix.
20 * Alan Cox : Started proper garbage collector
21 * Heiko EiBfeldt : Missing verify_area check
22 * Alan Cox : Started POSIXisms
23 * Andreas Schwab : Replace inode by dentry for proper
24 * reference counting
25 * Kirk Petersen : Made this a module
26 * Christoph Rohland : Elegant non-blocking accept/connect algorithm.
27 * Lots of bug fixes.
28 * Alexey Kuznetosv : Repaired (I hope) bugs introduces
29 * by above two patches.
30 * Andrea Arcangeli : If possible we block in connect(2)
31 * if the max backlog of the listen socket
32 * is been reached. This won't break
33 * old apps and it will avoid huge amount
34 * of socks hashed (this for unix_gc()
35 * performances reasons).
36 * Security fix that limits the max
37 * number of socks to 2*max_files and
38 * the number of skb queueable in the
39 * dgram receiver.
40 * Artur Skawina : Hash function optimizations
41 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
42 * Malcolm Beattie : Set peercred for socketpair
43 * Michal Ostrowski : Module initialization cleanup.
44 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT,
45 * the core infrastructure is doing that
46 * for all net proto families now (2.5.69+)
47 *
48 * Known differences from reference BSD that was tested:
49 *
50 * [TO FIX]
51 * ECONNREFUSED is not returned from one end of a connected() socket to the
52 * other the moment one end closes.
53 * fstat() doesn't return st_dev=0, and give the blksize as high water mark
54 * and a fake inode identifier (nor the BSD first socket fstat twice bug).
55 * [NOT TO FIX]
56 * accept() returns a path name even if the connecting socket has closed
57 * in the meantime (BSD loses the path and gives up).
58 * accept() returns 0 length path for an unbound connector. BSD returns 16
59 * and a null first byte in the path (but not for gethost/peername - BSD bug ??)
60 * socketpair(...SOCK_RAW..) doesn't panic the kernel.
61 * BSD af_unix apparently has connect forgetting to block properly.
62 * (need to check this with the POSIX spec in detail)
63 *
64 * Differences from 2.0.0-11-... (ANK)
65 * Bug fixes and improvements.
66 * - client shutdown killed server socket.
67 * - removed all useless cli/sti pairs.
68 *
69 * Semantic changes/extensions.
70 * - generic control message passing.
71 * - SCM_CREDENTIALS control message.
72 * - "Abstract" (not FS based) socket bindings.
73 * Abstract names are sequences of bytes (not zero terminated)
74 * started by 0, so that this name space does not intersect
75 * with BSD names.
76 */
77
78#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
79
80#include <linux/module.h>
81#include <linux/kernel.h>
82#include <linux/signal.h>
83#include <linux/sched/signal.h>
84#include <linux/errno.h>
85#include <linux/string.h>
86#include <linux/stat.h>
87#include <linux/dcache.h>
88#include <linux/namei.h>
89#include <linux/socket.h>
90#include <linux/un.h>
91#include <linux/fcntl.h>
92#include <linux/termios.h>
93#include <linux/sockios.h>
94#include <linux/net.h>
95#include <linux/in.h>
96#include <linux/fs.h>
97#include <linux/slab.h>
98#include <linux/uaccess.h>
99#include <linux/skbuff.h>
100#include <linux/netdevice.h>
101#include <net/net_namespace.h>
102#include <net/sock.h>
103#include <net/tcp_states.h>
104#include <net/af_unix.h>
105#include <linux/proc_fs.h>
106#include <linux/seq_file.h>
107#include <net/scm.h>
108#include <linux/init.h>
109#include <linux/poll.h>
110#include <linux/rtnetlink.h>
111#include <linux/mount.h>
112#include <net/checksum.h>
113#include <linux/security.h>
114#include <linux/freezer.h>
115#include <linux/file.h>
116
117#include "scm.h"
118
119struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
120EXPORT_SYMBOL_GPL(unix_socket_table);
121DEFINE_SPINLOCK(unix_table_lock);
122EXPORT_SYMBOL_GPL(unix_table_lock);
123static atomic_long_t unix_nr_socks;
124
125
126static struct hlist_head *unix_sockets_unbound(void *addr)
127{
128 unsigned long hash = (unsigned long)addr;
129
130 hash ^= hash >> 16;
131 hash ^= hash >> 8;
132 hash %= UNIX_HASH_SIZE;
133 return &unix_socket_table[UNIX_HASH_SIZE + hash];
134}
135
136#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
137
138#ifdef CONFIG_SECURITY_NETWORK
139static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
140{
141 UNIXCB(skb).secid = scm->secid;
142}
143
144static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
145{
146 scm->secid = UNIXCB(skb).secid;
147}
148
149static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
150{
151 return (scm->secid == UNIXCB(skb).secid);
152}
153#else
154static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
155{ }
156
157static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
158{ }
159
160static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
161{
162 return true;
163}
164#endif /* CONFIG_SECURITY_NETWORK */
165
166/*
167 * SMP locking strategy:
168 * hash table is protected with spinlock unix_table_lock
169 * each socket state is protected by separate spin lock.
170 */
171
172static inline unsigned int unix_hash_fold(__wsum n)
173{
174 unsigned int hash = (__force unsigned int)csum_fold(n);
175
176 hash ^= hash>>8;
177 return hash&(UNIX_HASH_SIZE-1);
178}
179
180#define unix_peer(sk) (unix_sk(sk)->peer)
181
182static inline int unix_our_peer(struct sock *sk, struct sock *osk)
183{
184 return unix_peer(osk) == sk;
185}
186
187static inline int unix_may_send(struct sock *sk, struct sock *osk)
188{
189 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
190}
191
192static inline int unix_recvq_full(const struct sock *sk)
193{
194 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
195}
196
197static inline int unix_recvq_full_lockless(const struct sock *sk)
198{
199 return skb_queue_len_lockless(&sk->sk_receive_queue) >
200 READ_ONCE(sk->sk_max_ack_backlog);
201}
202
203struct sock *unix_peer_get(struct sock *s)
204{
205 struct sock *peer;
206
207 unix_state_lock(s);
208 peer = unix_peer(s);
209 if (peer)
210 sock_hold(peer);
211 unix_state_unlock(s);
212 return peer;
213}
214EXPORT_SYMBOL_GPL(unix_peer_get);
215
216static inline void unix_release_addr(struct unix_address *addr)
217{
218 if (refcount_dec_and_test(&addr->refcnt))
219 kfree(addr);
220}
221
222/*
223 * Check unix socket name:
224 * - should be not zero length.
225 * - if started by not zero, should be NULL terminated (FS object)
226 * - if started by zero, it is abstract name.
227 */
228
229static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
230{
231 *hashp = 0;
232
233 if (len <= sizeof(short) || len > sizeof(*sunaddr))
234 return -EINVAL;
235 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
236 return -EINVAL;
237 if (sunaddr->sun_path[0]) {
238 /*
239 * This may look like an off by one error but it is a bit more
240 * subtle. 108 is the longest valid AF_UNIX path for a binding.
241 * sun_path[108] doesn't as such exist. However in kernel space
242 * we are guaranteed that it is a valid memory location in our
243 * kernel address buffer.
244 */
245 ((char *)sunaddr)[len] = 0;
246 len = strlen(sunaddr->sun_path)+1+sizeof(short);
247 return len;
248 }
249
250 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
251 return len;
252}
253
254static void __unix_remove_socket(struct sock *sk)
255{
256 sk_del_node_init(sk);
257}
258
259static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
260{
261 WARN_ON(!sk_unhashed(sk));
262 sk_add_node(sk, list);
263}
264
265static void __unix_set_addr(struct sock *sk, struct unix_address *addr,
266 unsigned hash)
267{
268 __unix_remove_socket(sk);
269 smp_store_release(&unix_sk(sk)->addr, addr);
270 __unix_insert_socket(&unix_socket_table[hash], sk);
271}
272
273static inline void unix_remove_socket(struct sock *sk)
274{
275 spin_lock(&unix_table_lock);
276 __unix_remove_socket(sk);
277 spin_unlock(&unix_table_lock);
278}
279
280static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
281{
282 spin_lock(&unix_table_lock);
283 __unix_insert_socket(list, sk);
284 spin_unlock(&unix_table_lock);
285}
286
287static struct sock *__unix_find_socket_byname(struct net *net,
288 struct sockaddr_un *sunname,
289 int len, unsigned int hash)
290{
291 struct sock *s;
292
293 sk_for_each(s, &unix_socket_table[hash]) {
294 struct unix_sock *u = unix_sk(s);
295
296 if (!net_eq(sock_net(s), net))
297 continue;
298
299 if (u->addr->len == len &&
300 !memcmp(u->addr->name, sunname, len))
301 return s;
302 }
303 return NULL;
304}
305
306static inline struct sock *unix_find_socket_byname(struct net *net,
307 struct sockaddr_un *sunname,
308 int len, unsigned int hash)
309{
310 struct sock *s;
311
312 spin_lock(&unix_table_lock);
313 s = __unix_find_socket_byname(net, sunname, len, hash);
314 if (s)
315 sock_hold(s);
316 spin_unlock(&unix_table_lock);
317 return s;
318}
319
320static struct sock *unix_find_socket_byinode(struct inode *i)
321{
322 struct sock *s;
323
324 spin_lock(&unix_table_lock);
325 sk_for_each(s,
326 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
327 struct dentry *dentry = unix_sk(s)->path.dentry;
328
329 if (dentry && d_backing_inode(dentry) == i) {
330 sock_hold(s);
331 goto found;
332 }
333 }
334 s = NULL;
335found:
336 spin_unlock(&unix_table_lock);
337 return s;
338}
339
340/* Support code for asymmetrically connected dgram sockets
341 *
342 * If a datagram socket is connected to a socket not itself connected
343 * to the first socket (eg, /dev/log), clients may only enqueue more
344 * messages if the present receive queue of the server socket is not
345 * "too large". This means there's a second writeability condition
346 * poll and sendmsg need to test. The dgram recv code will do a wake
347 * up on the peer_wait wait queue of a socket upon reception of a
348 * datagram which needs to be propagated to sleeping would-be writers
349 * since these might not have sent anything so far. This can't be
350 * accomplished via poll_wait because the lifetime of the server
351 * socket might be less than that of its clients if these break their
352 * association with it or if the server socket is closed while clients
353 * are still connected to it and there's no way to inform "a polling
354 * implementation" that it should let go of a certain wait queue
355 *
356 * In order to propagate a wake up, a wait_queue_entry_t of the client
357 * socket is enqueued on the peer_wait queue of the server socket
358 * whose wake function does a wake_up on the ordinary client socket
359 * wait queue. This connection is established whenever a write (or
360 * poll for write) hit the flow control condition and broken when the
361 * association to the server socket is dissolved or after a wake up
362 * was relayed.
363 */
364
365static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
366 void *key)
367{
368 struct unix_sock *u;
369 wait_queue_head_t *u_sleep;
370
371 u = container_of(q, struct unix_sock, peer_wake);
372
373 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
374 q);
375 u->peer_wake.private = NULL;
376
377 /* relaying can only happen while the wq still exists */
378 u_sleep = sk_sleep(&u->sk);
379 if (u_sleep)
380 wake_up_interruptible_poll(u_sleep, key_to_poll(key));
381
382 return 0;
383}
384
385static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
386{
387 struct unix_sock *u, *u_other;
388 int rc;
389
390 u = unix_sk(sk);
391 u_other = unix_sk(other);
392 rc = 0;
393 spin_lock(&u_other->peer_wait.lock);
394
395 if (!u->peer_wake.private) {
396 u->peer_wake.private = other;
397 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
398
399 rc = 1;
400 }
401
402 spin_unlock(&u_other->peer_wait.lock);
403 return rc;
404}
405
406static void unix_dgram_peer_wake_disconnect(struct sock *sk,
407 struct sock *other)
408{
409 struct unix_sock *u, *u_other;
410
411 u = unix_sk(sk);
412 u_other = unix_sk(other);
413 spin_lock(&u_other->peer_wait.lock);
414
415 if (u->peer_wake.private == other) {
416 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
417 u->peer_wake.private = NULL;
418 }
419
420 spin_unlock(&u_other->peer_wait.lock);
421}
422
423static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
424 struct sock *other)
425{
426 unix_dgram_peer_wake_disconnect(sk, other);
427 wake_up_interruptible_poll(sk_sleep(sk),
428 EPOLLOUT |
429 EPOLLWRNORM |
430 EPOLLWRBAND);
431}
432
433/* preconditions:
434 * - unix_peer(sk) == other
435 * - association is stable
436 */
437static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
438{
439 int connected;
440
441 connected = unix_dgram_peer_wake_connect(sk, other);
442
443 /* If other is SOCK_DEAD, we want to make sure we signal
444 * POLLOUT, such that a subsequent write() can get a
445 * -ECONNREFUSED. Otherwise, if we haven't queued any skbs
446 * to other and its full, we will hang waiting for POLLOUT.
447 */
448 if (unix_recvq_full(other) && !sock_flag(other, SOCK_DEAD))
449 return 1;
450
451 if (connected)
452 unix_dgram_peer_wake_disconnect(sk, other);
453
454 return 0;
455}
456
457static int unix_writable(const struct sock *sk)
458{
459 return sk->sk_state != TCP_LISTEN &&
460 (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
461}
462
463static void unix_write_space(struct sock *sk)
464{
465 struct socket_wq *wq;
466
467 rcu_read_lock();
468 if (unix_writable(sk)) {
469 wq = rcu_dereference(sk->sk_wq);
470 if (skwq_has_sleeper(wq))
471 wake_up_interruptible_sync_poll(&wq->wait,
472 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
473 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
474 }
475 rcu_read_unlock();
476}
477
478/* When dgram socket disconnects (or changes its peer), we clear its receive
479 * queue of packets arrived from previous peer. First, it allows to do
480 * flow control based only on wmem_alloc; second, sk connected to peer
481 * may receive messages only from that peer. */
482static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
483{
484 if (!skb_queue_empty(&sk->sk_receive_queue)) {
485 skb_queue_purge(&sk->sk_receive_queue);
486 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
487
488 /* If one link of bidirectional dgram pipe is disconnected,
489 * we signal error. Messages are lost. Do not make this,
490 * when peer was not connected to us.
491 */
492 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
493 other->sk_err = ECONNRESET;
494 sk_error_report(other);
495 }
496 }
497}
498
499static void unix_sock_destructor(struct sock *sk)
500{
501 struct unix_sock *u = unix_sk(sk);
502
503 skb_queue_purge(&sk->sk_receive_queue);
504
505 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
506 WARN_ON(!sk_unhashed(sk));
507 WARN_ON(sk->sk_socket);
508 if (!sock_flag(sk, SOCK_DEAD)) {
509 pr_info("Attempt to release alive unix socket: %p\n", sk);
510 return;
511 }
512
513 if (u->addr)
514 unix_release_addr(u->addr);
515
516 atomic_long_dec(&unix_nr_socks);
517 local_bh_disable();
518 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
519 local_bh_enable();
520#ifdef UNIX_REFCNT_DEBUG
521 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
522 atomic_long_read(&unix_nr_socks));
523#endif
524}
525
526static void unix_release_sock(struct sock *sk, int embrion)
527{
528 struct unix_sock *u = unix_sk(sk);
529 struct path path;
530 struct sock *skpair;
531 struct sk_buff *skb;
532 int state;
533
534 unix_remove_socket(sk);
535
536 /* Clear state */
537 unix_state_lock(sk);
538 sock_orphan(sk);
539 sk->sk_shutdown = SHUTDOWN_MASK;
540 path = u->path;
541 u->path.dentry = NULL;
542 u->path.mnt = NULL;
543 state = sk->sk_state;
544 sk->sk_state = TCP_CLOSE;
545
546 skpair = unix_peer(sk);
547 unix_peer(sk) = NULL;
548
549 unix_state_unlock(sk);
550
551 wake_up_interruptible_all(&u->peer_wait);
552
553 if (skpair != NULL) {
554 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
555 unix_state_lock(skpair);
556 /* No more writes */
557 skpair->sk_shutdown = SHUTDOWN_MASK;
558 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
559 skpair->sk_err = ECONNRESET;
560 unix_state_unlock(skpair);
561 skpair->sk_state_change(skpair);
562 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
563 }
564
565 unix_dgram_peer_wake_disconnect(sk, skpair);
566 sock_put(skpair); /* It may now die */
567 }
568
569 /* Try to flush out this socket. Throw out buffers at least */
570
571 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
572 if (state == TCP_LISTEN)
573 unix_release_sock(skb->sk, 1);
574 /* passed fds are erased in the kfree_skb hook */
575 UNIXCB(skb).consumed = skb->len;
576 kfree_skb(skb);
577 }
578
579 if (path.dentry)
580 path_put(&path);
581
582 sock_put(sk);
583
584 /* ---- Socket is dead now and most probably destroyed ---- */
585
586 /*
587 * Fixme: BSD difference: In BSD all sockets connected to us get
588 * ECONNRESET and we die on the spot. In Linux we behave
589 * like files and pipes do and wait for the last
590 * dereference.
591 *
592 * Can't we simply set sock->err?
593 *
594 * What the above comment does talk about? --ANK(980817)
595 */
596
597 if (unix_tot_inflight)
598 unix_gc(); /* Garbage collect fds */
599}
600
601static void init_peercred(struct sock *sk)
602{
603 const struct cred *old_cred;
604 struct pid *old_pid;
605
606 spin_lock(&sk->sk_peer_lock);
607 old_pid = sk->sk_peer_pid;
608 old_cred = sk->sk_peer_cred;
609 sk->sk_peer_pid = get_pid(task_tgid(current));
610 sk->sk_peer_cred = get_current_cred();
611 spin_unlock(&sk->sk_peer_lock);
612
613 put_pid(old_pid);
614 put_cred(old_cred);
615}
616
617static void copy_peercred(struct sock *sk, struct sock *peersk)
618{
619 const struct cred *old_cred;
620 struct pid *old_pid;
621
622 if (sk < peersk) {
623 spin_lock(&sk->sk_peer_lock);
624 spin_lock_nested(&peersk->sk_peer_lock, SINGLE_DEPTH_NESTING);
625 } else {
626 spin_lock(&peersk->sk_peer_lock);
627 spin_lock_nested(&sk->sk_peer_lock, SINGLE_DEPTH_NESTING);
628 }
629 old_pid = sk->sk_peer_pid;
630 old_cred = sk->sk_peer_cred;
631 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
632 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
633
634 spin_unlock(&sk->sk_peer_lock);
635 spin_unlock(&peersk->sk_peer_lock);
636
637 put_pid(old_pid);
638 put_cred(old_cred);
639}
640
641static int unix_listen(struct socket *sock, int backlog)
642{
643 int err;
644 struct sock *sk = sock->sk;
645 struct unix_sock *u = unix_sk(sk);
646
647 err = -EOPNOTSUPP;
648 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
649 goto out; /* Only stream/seqpacket sockets accept */
650 err = -EINVAL;
651 if (!u->addr)
652 goto out; /* No listens on an unbound socket */
653 unix_state_lock(sk);
654 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
655 goto out_unlock;
656 if (backlog > sk->sk_max_ack_backlog)
657 wake_up_interruptible_all(&u->peer_wait);
658 sk->sk_max_ack_backlog = backlog;
659 sk->sk_state = TCP_LISTEN;
660 /* set credentials so connect can copy them */
661 init_peercred(sk);
662 err = 0;
663
664out_unlock:
665 unix_state_unlock(sk);
666out:
667 return err;
668}
669
670static int unix_release(struct socket *);
671static int unix_bind(struct socket *, struct sockaddr *, int);
672static int unix_stream_connect(struct socket *, struct sockaddr *,
673 int addr_len, int flags);
674static int unix_socketpair(struct socket *, struct socket *);
675static int unix_accept(struct socket *, struct socket *, int, bool);
676static int unix_getname(struct socket *, struct sockaddr *, int);
677static __poll_t unix_poll(struct file *, struct socket *, poll_table *);
678static __poll_t unix_dgram_poll(struct file *, struct socket *,
679 poll_table *);
680static int unix_ioctl(struct socket *, unsigned int, unsigned long);
681#ifdef CONFIG_COMPAT
682static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
683#endif
684static int unix_shutdown(struct socket *, int);
685static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
686static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
687static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
688 size_t size, int flags);
689static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
690 struct pipe_inode_info *, size_t size,
691 unsigned int flags);
692static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
693static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
694static int unix_dgram_connect(struct socket *, struct sockaddr *,
695 int, int);
696static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
697static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
698 int);
699
700static int unix_set_peek_off(struct sock *sk, int val)
701{
702 struct unix_sock *u = unix_sk(sk);
703
704 if (mutex_lock_interruptible(&u->iolock))
705 return -EINTR;
706
707 sk->sk_peek_off = val;
708 mutex_unlock(&u->iolock);
709
710 return 0;
711}
712
713#ifdef CONFIG_PROC_FS
714static void unix_show_fdinfo(struct seq_file *m, struct socket *sock)
715{
716 struct sock *sk = sock->sk;
717 struct unix_sock *u;
718
719 if (sk) {
720 u = unix_sk(sock->sk);
721 seq_printf(m, "scm_fds: %u\n",
722 atomic_read(&u->scm_stat.nr_fds));
723 }
724}
725#else
726#define unix_show_fdinfo NULL
727#endif
728
729static const struct proto_ops unix_stream_ops = {
730 .family = PF_UNIX,
731 .owner = THIS_MODULE,
732 .release = unix_release,
733 .bind = unix_bind,
734 .connect = unix_stream_connect,
735 .socketpair = unix_socketpair,
736 .accept = unix_accept,
737 .getname = unix_getname,
738 .poll = unix_poll,
739 .ioctl = unix_ioctl,
740#ifdef CONFIG_COMPAT
741 .compat_ioctl = unix_compat_ioctl,
742#endif
743 .listen = unix_listen,
744 .shutdown = unix_shutdown,
745 .sendmsg = unix_stream_sendmsg,
746 .recvmsg = unix_stream_recvmsg,
747 .mmap = sock_no_mmap,
748 .sendpage = unix_stream_sendpage,
749 .splice_read = unix_stream_splice_read,
750 .set_peek_off = unix_set_peek_off,
751 .show_fdinfo = unix_show_fdinfo,
752};
753
754static const struct proto_ops unix_dgram_ops = {
755 .family = PF_UNIX,
756 .owner = THIS_MODULE,
757 .release = unix_release,
758 .bind = unix_bind,
759 .connect = unix_dgram_connect,
760 .socketpair = unix_socketpair,
761 .accept = sock_no_accept,
762 .getname = unix_getname,
763 .poll = unix_dgram_poll,
764 .ioctl = unix_ioctl,
765#ifdef CONFIG_COMPAT
766 .compat_ioctl = unix_compat_ioctl,
767#endif
768 .listen = sock_no_listen,
769 .shutdown = unix_shutdown,
770 .sendmsg = unix_dgram_sendmsg,
771 .recvmsg = unix_dgram_recvmsg,
772 .mmap = sock_no_mmap,
773 .sendpage = sock_no_sendpage,
774 .set_peek_off = unix_set_peek_off,
775 .show_fdinfo = unix_show_fdinfo,
776};
777
778static const struct proto_ops unix_seqpacket_ops = {
779 .family = PF_UNIX,
780 .owner = THIS_MODULE,
781 .release = unix_release,
782 .bind = unix_bind,
783 .connect = unix_stream_connect,
784 .socketpair = unix_socketpair,
785 .accept = unix_accept,
786 .getname = unix_getname,
787 .poll = unix_dgram_poll,
788 .ioctl = unix_ioctl,
789#ifdef CONFIG_COMPAT
790 .compat_ioctl = unix_compat_ioctl,
791#endif
792 .listen = unix_listen,
793 .shutdown = unix_shutdown,
794 .sendmsg = unix_seqpacket_sendmsg,
795 .recvmsg = unix_seqpacket_recvmsg,
796 .mmap = sock_no_mmap,
797 .sendpage = sock_no_sendpage,
798 .set_peek_off = unix_set_peek_off,
799 .show_fdinfo = unix_show_fdinfo,
800};
801
802static struct proto unix_proto = {
803 .name = "UNIX",
804 .owner = THIS_MODULE,
805 .obj_size = sizeof(struct unix_sock),
806};
807
808static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
809{
810 struct sock *sk = NULL;
811 struct unix_sock *u;
812
813 atomic_long_inc(&unix_nr_socks);
814 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
815 goto out;
816
817 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
818 if (!sk)
819 goto out;
820
821 sock_init_data(sock, sk);
822
823 sk->sk_allocation = GFP_KERNEL_ACCOUNT;
824 sk->sk_write_space = unix_write_space;
825 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
826 sk->sk_destruct = unix_sock_destructor;
827 u = unix_sk(sk);
828 u->path.dentry = NULL;
829 u->path.mnt = NULL;
830 spin_lock_init(&u->lock);
831 atomic_long_set(&u->inflight, 0);
832 INIT_LIST_HEAD(&u->link);
833 mutex_init(&u->iolock); /* single task reading lock */
834 mutex_init(&u->bindlock); /* single task binding lock */
835 init_waitqueue_head(&u->peer_wait);
836 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
837 memset(&u->scm_stat, 0, sizeof(struct scm_stat));
838 unix_insert_socket(unix_sockets_unbound(sk), sk);
839out:
840 if (sk == NULL)
841 atomic_long_dec(&unix_nr_socks);
842 else {
843 local_bh_disable();
844 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
845 local_bh_enable();
846 }
847 return sk;
848}
849
850static int unix_create(struct net *net, struct socket *sock, int protocol,
851 int kern)
852{
853 if (protocol && protocol != PF_UNIX)
854 return -EPROTONOSUPPORT;
855
856 sock->state = SS_UNCONNECTED;
857
858 switch (sock->type) {
859 case SOCK_STREAM:
860 sock->ops = &unix_stream_ops;
861 break;
862 /*
863 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
864 * nothing uses it.
865 */
866 case SOCK_RAW:
867 sock->type = SOCK_DGRAM;
868 fallthrough;
869 case SOCK_DGRAM:
870 sock->ops = &unix_dgram_ops;
871 break;
872 case SOCK_SEQPACKET:
873 sock->ops = &unix_seqpacket_ops;
874 break;
875 default:
876 return -ESOCKTNOSUPPORT;
877 }
878
879 return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
880}
881
882static int unix_release(struct socket *sock)
883{
884 struct sock *sk = sock->sk;
885
886 if (!sk)
887 return 0;
888
889 unix_release_sock(sk, 0);
890 sock->sk = NULL;
891
892 return 0;
893}
894
895static int unix_autobind(struct socket *sock)
896{
897 struct sock *sk = sock->sk;
898 struct net *net = sock_net(sk);
899 struct unix_sock *u = unix_sk(sk);
900 static u32 ordernum = 1;
901 struct unix_address *addr;
902 int err;
903 unsigned int retries = 0;
904
905 err = mutex_lock_interruptible(&u->bindlock);
906 if (err)
907 return err;
908
909 if (u->addr)
910 goto out;
911
912 err = -ENOMEM;
913 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
914 if (!addr)
915 goto out;
916
917 addr->name->sun_family = AF_UNIX;
918 refcount_set(&addr->refcnt, 1);
919
920retry:
921 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
922 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
923 addr->hash ^= sk->sk_type;
924
925 spin_lock(&unix_table_lock);
926 ordernum = (ordernum+1)&0xFFFFF;
927
928 if (__unix_find_socket_byname(net, addr->name, addr->len, addr->hash)) {
929 spin_unlock(&unix_table_lock);
930 /*
931 * __unix_find_socket_byname() may take long time if many names
932 * are already in use.
933 */
934 cond_resched();
935 /* Give up if all names seems to be in use. */
936 if (retries++ == 0xFFFFF) {
937 err = -ENOSPC;
938 kfree(addr);
939 goto out;
940 }
941 goto retry;
942 }
943
944 __unix_set_addr(sk, addr, addr->hash);
945 spin_unlock(&unix_table_lock);
946 err = 0;
947
948out: mutex_unlock(&u->bindlock);
949 return err;
950}
951
952static struct sock *unix_find_other(struct net *net,
953 struct sockaddr_un *sunname, int len,
954 int type, unsigned int hash, int *error)
955{
956 struct sock *u;
957 struct path path;
958 int err = 0;
959
960 if (sunname->sun_path[0]) {
961 struct inode *inode;
962 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
963 if (err)
964 goto fail;
965 inode = d_backing_inode(path.dentry);
966 err = path_permission(&path, MAY_WRITE);
967 if (err)
968 goto put_fail;
969
970 err = -ECONNREFUSED;
971 if (!S_ISSOCK(inode->i_mode))
972 goto put_fail;
973 u = unix_find_socket_byinode(inode);
974 if (!u)
975 goto put_fail;
976
977 if (u->sk_type == type)
978 touch_atime(&path);
979
980 path_put(&path);
981
982 err = -EPROTOTYPE;
983 if (u->sk_type != type) {
984 sock_put(u);
985 goto fail;
986 }
987 } else {
988 err = -ECONNREFUSED;
989 u = unix_find_socket_byname(net, sunname, len, type ^ hash);
990 if (u) {
991 struct dentry *dentry;
992 dentry = unix_sk(u)->path.dentry;
993 if (dentry)
994 touch_atime(&unix_sk(u)->path);
995 } else
996 goto fail;
997 }
998 return u;
999
1000put_fail:
1001 path_put(&path);
1002fail:
1003 *error = err;
1004 return NULL;
1005}
1006
1007static int unix_bind_bsd(struct sock *sk, struct unix_address *addr)
1008{
1009 struct unix_sock *u = unix_sk(sk);
1010 umode_t mode = S_IFSOCK |
1011 (SOCK_INODE(sk->sk_socket)->i_mode & ~current_umask());
1012 struct user_namespace *ns; // barf...
1013 struct path parent;
1014 struct dentry *dentry;
1015 unsigned int hash;
1016 int err;
1017
1018 /*
1019 * Get the parent directory, calculate the hash for last
1020 * component.
1021 */
1022 dentry = kern_path_create(AT_FDCWD, addr->name->sun_path, &parent, 0);
1023 if (IS_ERR(dentry))
1024 return PTR_ERR(dentry);
1025 ns = mnt_user_ns(parent.mnt);
1026
1027 /*
1028 * All right, let's create it.
1029 */
1030 err = security_path_mknod(&parent, dentry, mode, 0);
1031 if (!err)
1032 err = vfs_mknod(ns, d_inode(parent.dentry), dentry, mode, 0);
1033 if (err)
1034 goto out;
1035 err = mutex_lock_interruptible(&u->bindlock);
1036 if (err)
1037 goto out_unlink;
1038 if (u->addr)
1039 goto out_unlock;
1040
1041 addr->hash = UNIX_HASH_SIZE;
1042 hash = d_backing_inode(dentry)->i_ino & (UNIX_HASH_SIZE - 1);
1043 spin_lock(&unix_table_lock);
1044 u->path.mnt = mntget(parent.mnt);
1045 u->path.dentry = dget(dentry);
1046 __unix_set_addr(sk, addr, hash);
1047 spin_unlock(&unix_table_lock);
1048 mutex_unlock(&u->bindlock);
1049 done_path_create(&parent, dentry);
1050 return 0;
1051
1052out_unlock:
1053 mutex_unlock(&u->bindlock);
1054 err = -EINVAL;
1055out_unlink:
1056 /* failed after successful mknod? unlink what we'd created... */
1057 vfs_unlink(ns, d_inode(parent.dentry), dentry, NULL);
1058out:
1059 done_path_create(&parent, dentry);
1060 return err;
1061}
1062
1063static int unix_bind_abstract(struct sock *sk, struct unix_address *addr)
1064{
1065 struct unix_sock *u = unix_sk(sk);
1066 int err;
1067
1068 err = mutex_lock_interruptible(&u->bindlock);
1069 if (err)
1070 return err;
1071
1072 if (u->addr) {
1073 mutex_unlock(&u->bindlock);
1074 return -EINVAL;
1075 }
1076
1077 spin_lock(&unix_table_lock);
1078 if (__unix_find_socket_byname(sock_net(sk), addr->name, addr->len,
1079 addr->hash)) {
1080 spin_unlock(&unix_table_lock);
1081 mutex_unlock(&u->bindlock);
1082 return -EADDRINUSE;
1083 }
1084 __unix_set_addr(sk, addr, addr->hash);
1085 spin_unlock(&unix_table_lock);
1086 mutex_unlock(&u->bindlock);
1087 return 0;
1088}
1089
1090static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1091{
1092 struct sock *sk = sock->sk;
1093 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1094 char *sun_path = sunaddr->sun_path;
1095 int err;
1096 unsigned int hash;
1097 struct unix_address *addr;
1098
1099 if (addr_len < offsetofend(struct sockaddr_un, sun_family) ||
1100 sunaddr->sun_family != AF_UNIX)
1101 return -EINVAL;
1102
1103 if (addr_len == sizeof(short))
1104 return unix_autobind(sock);
1105
1106 err = unix_mkname(sunaddr, addr_len, &hash);
1107 if (err < 0)
1108 return err;
1109 addr_len = err;
1110 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
1111 if (!addr)
1112 return -ENOMEM;
1113
1114 memcpy(addr->name, sunaddr, addr_len);
1115 addr->len = addr_len;
1116 addr->hash = hash ^ sk->sk_type;
1117 refcount_set(&addr->refcnt, 1);
1118
1119 if (sun_path[0])
1120 err = unix_bind_bsd(sk, addr);
1121 else
1122 err = unix_bind_abstract(sk, addr);
1123 if (err)
1124 unix_release_addr(addr);
1125 return err == -EEXIST ? -EADDRINUSE : err;
1126}
1127
1128static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1129{
1130 if (unlikely(sk1 == sk2) || !sk2) {
1131 unix_state_lock(sk1);
1132 return;
1133 }
1134 if (sk1 < sk2) {
1135 unix_state_lock(sk1);
1136 unix_state_lock_nested(sk2);
1137 } else {
1138 unix_state_lock(sk2);
1139 unix_state_lock_nested(sk1);
1140 }
1141}
1142
1143static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1144{
1145 if (unlikely(sk1 == sk2) || !sk2) {
1146 unix_state_unlock(sk1);
1147 return;
1148 }
1149 unix_state_unlock(sk1);
1150 unix_state_unlock(sk2);
1151}
1152
1153static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1154 int alen, int flags)
1155{
1156 struct sock *sk = sock->sk;
1157 struct net *net = sock_net(sk);
1158 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1159 struct sock *other;
1160 unsigned int hash;
1161 int err;
1162
1163 err = -EINVAL;
1164 if (alen < offsetofend(struct sockaddr, sa_family))
1165 goto out;
1166
1167 if (addr->sa_family != AF_UNSPEC) {
1168 err = unix_mkname(sunaddr, alen, &hash);
1169 if (err < 0)
1170 goto out;
1171 alen = err;
1172
1173 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1174 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1175 goto out;
1176
1177restart:
1178 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1179 if (!other)
1180 goto out;
1181
1182 unix_state_double_lock(sk, other);
1183
1184 /* Apparently VFS overslept socket death. Retry. */
1185 if (sock_flag(other, SOCK_DEAD)) {
1186 unix_state_double_unlock(sk, other);
1187 sock_put(other);
1188 goto restart;
1189 }
1190
1191 err = -EPERM;
1192 if (!unix_may_send(sk, other))
1193 goto out_unlock;
1194
1195 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1196 if (err)
1197 goto out_unlock;
1198
1199 } else {
1200 /*
1201 * 1003.1g breaking connected state with AF_UNSPEC
1202 */
1203 other = NULL;
1204 unix_state_double_lock(sk, other);
1205 }
1206
1207 /*
1208 * If it was connected, reconnect.
1209 */
1210 if (unix_peer(sk)) {
1211 struct sock *old_peer = unix_peer(sk);
1212 unix_peer(sk) = other;
1213 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1214
1215 unix_state_double_unlock(sk, other);
1216
1217 if (other != old_peer)
1218 unix_dgram_disconnected(sk, old_peer);
1219 sock_put(old_peer);
1220 } else {
1221 unix_peer(sk) = other;
1222 unix_state_double_unlock(sk, other);
1223 }
1224 return 0;
1225
1226out_unlock:
1227 unix_state_double_unlock(sk, other);
1228 sock_put(other);
1229out:
1230 return err;
1231}
1232
1233static long unix_wait_for_peer(struct sock *other, long timeo)
1234 __releases(&unix_sk(other)->lock)
1235{
1236 struct unix_sock *u = unix_sk(other);
1237 int sched;
1238 DEFINE_WAIT(wait);
1239
1240 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1241
1242 sched = !sock_flag(other, SOCK_DEAD) &&
1243 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1244 unix_recvq_full(other);
1245
1246 unix_state_unlock(other);
1247
1248 if (sched)
1249 timeo = schedule_timeout(timeo);
1250
1251 finish_wait(&u->peer_wait, &wait);
1252 return timeo;
1253}
1254
1255static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1256 int addr_len, int flags)
1257{
1258 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1259 struct sock *sk = sock->sk;
1260 struct net *net = sock_net(sk);
1261 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1262 struct sock *newsk = NULL;
1263 struct sock *other = NULL;
1264 struct sk_buff *skb = NULL;
1265 unsigned int hash;
1266 int st;
1267 int err;
1268 long timeo;
1269
1270 err = unix_mkname(sunaddr, addr_len, &hash);
1271 if (err < 0)
1272 goto out;
1273 addr_len = err;
1274
1275 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1276 (err = unix_autobind(sock)) != 0)
1277 goto out;
1278
1279 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1280
1281 /* First of all allocate resources.
1282 If we will make it after state is locked,
1283 we will have to recheck all again in any case.
1284 */
1285
1286 err = -ENOMEM;
1287
1288 /* create new sock for complete connection */
1289 newsk = unix_create1(sock_net(sk), NULL, 0);
1290 if (newsk == NULL)
1291 goto out;
1292
1293 /* Allocate skb for sending to listening sock */
1294 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1295 if (skb == NULL)
1296 goto out;
1297
1298restart:
1299 /* Find listening sock. */
1300 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1301 if (!other)
1302 goto out;
1303
1304 /* Latch state of peer */
1305 unix_state_lock(other);
1306
1307 /* Apparently VFS overslept socket death. Retry. */
1308 if (sock_flag(other, SOCK_DEAD)) {
1309 unix_state_unlock(other);
1310 sock_put(other);
1311 goto restart;
1312 }
1313
1314 err = -ECONNREFUSED;
1315 if (other->sk_state != TCP_LISTEN)
1316 goto out_unlock;
1317 if (other->sk_shutdown & RCV_SHUTDOWN)
1318 goto out_unlock;
1319
1320 if (unix_recvq_full(other)) {
1321 err = -EAGAIN;
1322 if (!timeo)
1323 goto out_unlock;
1324
1325 timeo = unix_wait_for_peer(other, timeo);
1326
1327 err = sock_intr_errno(timeo);
1328 if (signal_pending(current))
1329 goto out;
1330 sock_put(other);
1331 goto restart;
1332 }
1333
1334 /* Latch our state.
1335
1336 It is tricky place. We need to grab our state lock and cannot
1337 drop lock on peer. It is dangerous because deadlock is
1338 possible. Connect to self case and simultaneous
1339 attempt to connect are eliminated by checking socket
1340 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1341 check this before attempt to grab lock.
1342
1343 Well, and we have to recheck the state after socket locked.
1344 */
1345 st = sk->sk_state;
1346
1347 switch (st) {
1348 case TCP_CLOSE:
1349 /* This is ok... continue with connect */
1350 break;
1351 case TCP_ESTABLISHED:
1352 /* Socket is already connected */
1353 err = -EISCONN;
1354 goto out_unlock;
1355 default:
1356 err = -EINVAL;
1357 goto out_unlock;
1358 }
1359
1360 unix_state_lock_nested(sk);
1361
1362 if (sk->sk_state != st) {
1363 unix_state_unlock(sk);
1364 unix_state_unlock(other);
1365 sock_put(other);
1366 goto restart;
1367 }
1368
1369 err = security_unix_stream_connect(sk, other, newsk);
1370 if (err) {
1371 unix_state_unlock(sk);
1372 goto out_unlock;
1373 }
1374
1375 /* The way is open! Fastly set all the necessary fields... */
1376
1377 sock_hold(sk);
1378 unix_peer(newsk) = sk;
1379 newsk->sk_state = TCP_ESTABLISHED;
1380 newsk->sk_type = sk->sk_type;
1381 init_peercred(newsk);
1382 newu = unix_sk(newsk);
1383 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1384 otheru = unix_sk(other);
1385
1386 /* copy address information from listening to new sock
1387 *
1388 * The contents of *(otheru->addr) and otheru->path
1389 * are seen fully set up here, since we have found
1390 * otheru in hash under unix_table_lock. Insertion
1391 * into the hash chain we'd found it in had been done
1392 * in an earlier critical area protected by unix_table_lock,
1393 * the same one where we'd set *(otheru->addr) contents,
1394 * as well as otheru->path and otheru->addr itself.
1395 *
1396 * Using smp_store_release() here to set newu->addr
1397 * is enough to make those stores, as well as stores
1398 * to newu->path visible to anyone who gets newu->addr
1399 * by smp_load_acquire(). IOW, the same warranties
1400 * as for unix_sock instances bound in unix_bind() or
1401 * in unix_autobind().
1402 */
1403 if (otheru->path.dentry) {
1404 path_get(&otheru->path);
1405 newu->path = otheru->path;
1406 }
1407 refcount_inc(&otheru->addr->refcnt);
1408 smp_store_release(&newu->addr, otheru->addr);
1409
1410 /* Set credentials */
1411 copy_peercred(sk, other);
1412
1413 sock->state = SS_CONNECTED;
1414 sk->sk_state = TCP_ESTABLISHED;
1415 sock_hold(newsk);
1416
1417 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1418 unix_peer(sk) = newsk;
1419
1420 unix_state_unlock(sk);
1421
1422 /* take ten and send info to listening sock */
1423 spin_lock(&other->sk_receive_queue.lock);
1424 __skb_queue_tail(&other->sk_receive_queue, skb);
1425 spin_unlock(&other->sk_receive_queue.lock);
1426 unix_state_unlock(other);
1427 other->sk_data_ready(other);
1428 sock_put(other);
1429 return 0;
1430
1431out_unlock:
1432 if (other)
1433 unix_state_unlock(other);
1434
1435out:
1436 kfree_skb(skb);
1437 if (newsk)
1438 unix_release_sock(newsk, 0);
1439 if (other)
1440 sock_put(other);
1441 return err;
1442}
1443
1444static int unix_socketpair(struct socket *socka, struct socket *sockb)
1445{
1446 struct sock *ska = socka->sk, *skb = sockb->sk;
1447
1448 /* Join our sockets back to back */
1449 sock_hold(ska);
1450 sock_hold(skb);
1451 unix_peer(ska) = skb;
1452 unix_peer(skb) = ska;
1453 init_peercred(ska);
1454 init_peercred(skb);
1455
1456 if (ska->sk_type != SOCK_DGRAM) {
1457 ska->sk_state = TCP_ESTABLISHED;
1458 skb->sk_state = TCP_ESTABLISHED;
1459 socka->state = SS_CONNECTED;
1460 sockb->state = SS_CONNECTED;
1461 }
1462 return 0;
1463}
1464
1465static void unix_sock_inherit_flags(const struct socket *old,
1466 struct socket *new)
1467{
1468 if (test_bit(SOCK_PASSCRED, &old->flags))
1469 set_bit(SOCK_PASSCRED, &new->flags);
1470 if (test_bit(SOCK_PASSSEC, &old->flags))
1471 set_bit(SOCK_PASSSEC, &new->flags);
1472}
1473
1474static int unix_accept(struct socket *sock, struct socket *newsock, int flags,
1475 bool kern)
1476{
1477 struct sock *sk = sock->sk;
1478 struct sock *tsk;
1479 struct sk_buff *skb;
1480 int err;
1481
1482 err = -EOPNOTSUPP;
1483 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1484 goto out;
1485
1486 err = -EINVAL;
1487 if (sk->sk_state != TCP_LISTEN)
1488 goto out;
1489
1490 /* If socket state is TCP_LISTEN it cannot change (for now...),
1491 * so that no locks are necessary.
1492 */
1493
1494 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1495 if (!skb) {
1496 /* This means receive shutdown. */
1497 if (err == 0)
1498 err = -EINVAL;
1499 goto out;
1500 }
1501
1502 tsk = skb->sk;
1503 skb_free_datagram(sk, skb);
1504 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1505
1506 /* attach accepted sock to socket */
1507 unix_state_lock(tsk);
1508 newsock->state = SS_CONNECTED;
1509 unix_sock_inherit_flags(sock, newsock);
1510 sock_graft(tsk, newsock);
1511 unix_state_unlock(tsk);
1512 return 0;
1513
1514out:
1515 return err;
1516}
1517
1518
1519static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1520{
1521 struct sock *sk = sock->sk;
1522 struct unix_address *addr;
1523 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1524 int err = 0;
1525
1526 if (peer) {
1527 sk = unix_peer_get(sk);
1528
1529 err = -ENOTCONN;
1530 if (!sk)
1531 goto out;
1532 err = 0;
1533 } else {
1534 sock_hold(sk);
1535 }
1536
1537 addr = smp_load_acquire(&unix_sk(sk)->addr);
1538 if (!addr) {
1539 sunaddr->sun_family = AF_UNIX;
1540 sunaddr->sun_path[0] = 0;
1541 err = sizeof(short);
1542 } else {
1543 err = addr->len;
1544 memcpy(sunaddr, addr->name, addr->len);
1545 }
1546 sock_put(sk);
1547out:
1548 return err;
1549}
1550
1551static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb)
1552{
1553 scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1554
1555 /*
1556 * Garbage collection of unix sockets starts by selecting a set of
1557 * candidate sockets which have reference only from being in flight
1558 * (total_refs == inflight_refs). This condition is checked once during
1559 * the candidate collection phase, and candidates are marked as such, so
1560 * that non-candidates can later be ignored. While inflight_refs is
1561 * protected by unix_gc_lock, total_refs (file count) is not, hence this
1562 * is an instantaneous decision.
1563 *
1564 * Once a candidate, however, the socket must not be reinstalled into a
1565 * file descriptor while the garbage collection is in progress.
1566 *
1567 * If the above conditions are met, then the directed graph of
1568 * candidates (*) does not change while unix_gc_lock is held.
1569 *
1570 * Any operations that changes the file count through file descriptors
1571 * (dup, close, sendmsg) does not change the graph since candidates are
1572 * not installed in fds.
1573 *
1574 * Dequeing a candidate via recvmsg would install it into an fd, but
1575 * that takes unix_gc_lock to decrement the inflight count, so it's
1576 * serialized with garbage collection.
1577 *
1578 * MSG_PEEK is special in that it does not change the inflight count,
1579 * yet does install the socket into an fd. The following lock/unlock
1580 * pair is to ensure serialization with garbage collection. It must be
1581 * done between incrementing the file count and installing the file into
1582 * an fd.
1583 *
1584 * If garbage collection starts after the barrier provided by the
1585 * lock/unlock, then it will see the elevated refcount and not mark this
1586 * as a candidate. If a garbage collection is already in progress
1587 * before the file count was incremented, then the lock/unlock pair will
1588 * ensure that garbage collection is finished before progressing to
1589 * installing the fd.
1590 *
1591 * (*) A -> B where B is on the queue of A or B is on the queue of C
1592 * which is on the queue of listening socket A.
1593 */
1594 spin_lock(&unix_gc_lock);
1595 spin_unlock(&unix_gc_lock);
1596}
1597
1598static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1599{
1600 int err = 0;
1601
1602 UNIXCB(skb).pid = get_pid(scm->pid);
1603 UNIXCB(skb).uid = scm->creds.uid;
1604 UNIXCB(skb).gid = scm->creds.gid;
1605 UNIXCB(skb).fp = NULL;
1606 unix_get_secdata(scm, skb);
1607 if (scm->fp && send_fds)
1608 err = unix_attach_fds(scm, skb);
1609
1610 skb->destructor = unix_destruct_scm;
1611 return err;
1612}
1613
1614static bool unix_passcred_enabled(const struct socket *sock,
1615 const struct sock *other)
1616{
1617 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1618 !other->sk_socket ||
1619 test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1620}
1621
1622/*
1623 * Some apps rely on write() giving SCM_CREDENTIALS
1624 * We include credentials if source or destination socket
1625 * asserted SOCK_PASSCRED.
1626 */
1627static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1628 const struct sock *other)
1629{
1630 if (UNIXCB(skb).pid)
1631 return;
1632 if (unix_passcred_enabled(sock, other)) {
1633 UNIXCB(skb).pid = get_pid(task_tgid(current));
1634 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1635 }
1636}
1637
1638static int maybe_init_creds(struct scm_cookie *scm,
1639 struct socket *socket,
1640 const struct sock *other)
1641{
1642 int err;
1643 struct msghdr msg = { .msg_controllen = 0 };
1644
1645 err = scm_send(socket, &msg, scm, false);
1646 if (err)
1647 return err;
1648
1649 if (unix_passcred_enabled(socket, other)) {
1650 scm->pid = get_pid(task_tgid(current));
1651 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1652 }
1653 return err;
1654}
1655
1656static bool unix_skb_scm_eq(struct sk_buff *skb,
1657 struct scm_cookie *scm)
1658{
1659 const struct unix_skb_parms *u = &UNIXCB(skb);
1660
1661 return u->pid == scm->pid &&
1662 uid_eq(u->uid, scm->creds.uid) &&
1663 gid_eq(u->gid, scm->creds.gid) &&
1664 unix_secdata_eq(scm, skb);
1665}
1666
1667static void scm_stat_add(struct sock *sk, struct sk_buff *skb)
1668{
1669 struct scm_fp_list *fp = UNIXCB(skb).fp;
1670 struct unix_sock *u = unix_sk(sk);
1671
1672 if (unlikely(fp && fp->count))
1673 atomic_add(fp->count, &u->scm_stat.nr_fds);
1674}
1675
1676static void scm_stat_del(struct sock *sk, struct sk_buff *skb)
1677{
1678 struct scm_fp_list *fp = UNIXCB(skb).fp;
1679 struct unix_sock *u = unix_sk(sk);
1680
1681 if (unlikely(fp && fp->count))
1682 atomic_sub(fp->count, &u->scm_stat.nr_fds);
1683}
1684
1685/*
1686 * Send AF_UNIX data.
1687 */
1688
1689static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1690 size_t len)
1691{
1692 struct sock *sk = sock->sk;
1693 struct net *net = sock_net(sk);
1694 struct unix_sock *u = unix_sk(sk);
1695 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1696 struct sock *other = NULL;
1697 int namelen = 0; /* fake GCC */
1698 int err;
1699 unsigned int hash;
1700 struct sk_buff *skb;
1701 long timeo;
1702 struct scm_cookie scm;
1703 int data_len = 0;
1704 int sk_locked;
1705
1706 wait_for_unix_gc();
1707 err = scm_send(sock, msg, &scm, false);
1708 if (err < 0)
1709 return err;
1710
1711 err = -EOPNOTSUPP;
1712 if (msg->msg_flags&MSG_OOB)
1713 goto out;
1714
1715 if (msg->msg_namelen) {
1716 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1717 if (err < 0)
1718 goto out;
1719 namelen = err;
1720 } else {
1721 sunaddr = NULL;
1722 err = -ENOTCONN;
1723 other = unix_peer_get(sk);
1724 if (!other)
1725 goto out;
1726 }
1727
1728 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1729 && (err = unix_autobind(sock)) != 0)
1730 goto out;
1731
1732 err = -EMSGSIZE;
1733 if (len > sk->sk_sndbuf - 32)
1734 goto out;
1735
1736 if (len > SKB_MAX_ALLOC) {
1737 data_len = min_t(size_t,
1738 len - SKB_MAX_ALLOC,
1739 MAX_SKB_FRAGS * PAGE_SIZE);
1740 data_len = PAGE_ALIGN(data_len);
1741
1742 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1743 }
1744
1745 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1746 msg->msg_flags & MSG_DONTWAIT, &err,
1747 PAGE_ALLOC_COSTLY_ORDER);
1748 if (skb == NULL)
1749 goto out;
1750
1751 err = unix_scm_to_skb(&scm, skb, true);
1752 if (err < 0)
1753 goto out_free;
1754
1755 skb_put(skb, len - data_len);
1756 skb->data_len = data_len;
1757 skb->len = len;
1758 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1759 if (err)
1760 goto out_free;
1761
1762 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1763
1764restart:
1765 if (!other) {
1766 err = -ECONNRESET;
1767 if (sunaddr == NULL)
1768 goto out_free;
1769
1770 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1771 hash, &err);
1772 if (other == NULL)
1773 goto out_free;
1774 }
1775
1776 if (sk_filter(other, skb) < 0) {
1777 /* Toss the packet but do not return any error to the sender */
1778 err = len;
1779 goto out_free;
1780 }
1781
1782 sk_locked = 0;
1783 unix_state_lock(other);
1784restart_locked:
1785 err = -EPERM;
1786 if (!unix_may_send(sk, other))
1787 goto out_unlock;
1788
1789 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1790 /*
1791 * Check with 1003.1g - what should
1792 * datagram error
1793 */
1794 unix_state_unlock(other);
1795 sock_put(other);
1796
1797 if (!sk_locked)
1798 unix_state_lock(sk);
1799
1800 err = 0;
1801 if (unix_peer(sk) == other) {
1802 unix_peer(sk) = NULL;
1803 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1804
1805 unix_state_unlock(sk);
1806
1807 unix_dgram_disconnected(sk, other);
1808 sock_put(other);
1809 err = -ECONNREFUSED;
1810 } else {
1811 unix_state_unlock(sk);
1812 }
1813
1814 other = NULL;
1815 if (err)
1816 goto out_free;
1817 goto restart;
1818 }
1819
1820 err = -EPIPE;
1821 if (other->sk_shutdown & RCV_SHUTDOWN)
1822 goto out_unlock;
1823
1824 if (sk->sk_type != SOCK_SEQPACKET) {
1825 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1826 if (err)
1827 goto out_unlock;
1828 }
1829
1830 /* other == sk && unix_peer(other) != sk if
1831 * - unix_peer(sk) == NULL, destination address bound to sk
1832 * - unix_peer(sk) == sk by time of get but disconnected before lock
1833 */
1834 if (other != sk &&
1835 unlikely(unix_peer(other) != sk &&
1836 unix_recvq_full_lockless(other))) {
1837 if (timeo) {
1838 timeo = unix_wait_for_peer(other, timeo);
1839
1840 err = sock_intr_errno(timeo);
1841 if (signal_pending(current))
1842 goto out_free;
1843
1844 goto restart;
1845 }
1846
1847 if (!sk_locked) {
1848 unix_state_unlock(other);
1849 unix_state_double_lock(sk, other);
1850 }
1851
1852 if (unix_peer(sk) != other ||
1853 unix_dgram_peer_wake_me(sk, other)) {
1854 err = -EAGAIN;
1855 sk_locked = 1;
1856 goto out_unlock;
1857 }
1858
1859 if (!sk_locked) {
1860 sk_locked = 1;
1861 goto restart_locked;
1862 }
1863 }
1864
1865 if (unlikely(sk_locked))
1866 unix_state_unlock(sk);
1867
1868 if (sock_flag(other, SOCK_RCVTSTAMP))
1869 __net_timestamp(skb);
1870 maybe_add_creds(skb, sock, other);
1871 scm_stat_add(other, skb);
1872 skb_queue_tail(&other->sk_receive_queue, skb);
1873 unix_state_unlock(other);
1874 other->sk_data_ready(other);
1875 sock_put(other);
1876 scm_destroy(&scm);
1877 return len;
1878
1879out_unlock:
1880 if (sk_locked)
1881 unix_state_unlock(sk);
1882 unix_state_unlock(other);
1883out_free:
1884 kfree_skb(skb);
1885out:
1886 if (other)
1887 sock_put(other);
1888 scm_destroy(&scm);
1889 return err;
1890}
1891
1892/* We use paged skbs for stream sockets, and limit occupancy to 32768
1893 * bytes, and a minimum of a full page.
1894 */
1895#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1896
1897static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
1898 size_t len)
1899{
1900 struct sock *sk = sock->sk;
1901 struct sock *other = NULL;
1902 int err, size;
1903 struct sk_buff *skb;
1904 int sent = 0;
1905 struct scm_cookie scm;
1906 bool fds_sent = false;
1907 int data_len;
1908
1909 wait_for_unix_gc();
1910 err = scm_send(sock, msg, &scm, false);
1911 if (err < 0)
1912 return err;
1913
1914 err = -EOPNOTSUPP;
1915 if (msg->msg_flags&MSG_OOB)
1916 goto out_err;
1917
1918 if (msg->msg_namelen) {
1919 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1920 goto out_err;
1921 } else {
1922 err = -ENOTCONN;
1923 other = unix_peer(sk);
1924 if (!other)
1925 goto out_err;
1926 }
1927
1928 if (sk->sk_shutdown & SEND_SHUTDOWN)
1929 goto pipe_err;
1930
1931 while (sent < len) {
1932 size = len - sent;
1933
1934 /* Keep two messages in the pipe so it schedules better */
1935 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1936
1937 /* allow fallback to order-0 allocations */
1938 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1939
1940 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1941
1942 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
1943
1944 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1945 msg->msg_flags & MSG_DONTWAIT, &err,
1946 get_order(UNIX_SKB_FRAGS_SZ));
1947 if (!skb)
1948 goto out_err;
1949
1950 /* Only send the fds in the first buffer */
1951 err = unix_scm_to_skb(&scm, skb, !fds_sent);
1952 if (err < 0) {
1953 kfree_skb(skb);
1954 goto out_err;
1955 }
1956 fds_sent = true;
1957
1958 skb_put(skb, size - data_len);
1959 skb->data_len = data_len;
1960 skb->len = size;
1961 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
1962 if (err) {
1963 kfree_skb(skb);
1964 goto out_err;
1965 }
1966
1967 unix_state_lock(other);
1968
1969 if (sock_flag(other, SOCK_DEAD) ||
1970 (other->sk_shutdown & RCV_SHUTDOWN))
1971 goto pipe_err_free;
1972
1973 maybe_add_creds(skb, sock, other);
1974 scm_stat_add(other, skb);
1975 skb_queue_tail(&other->sk_receive_queue, skb);
1976 unix_state_unlock(other);
1977 other->sk_data_ready(other);
1978 sent += size;
1979 }
1980
1981 scm_destroy(&scm);
1982
1983 return sent;
1984
1985pipe_err_free:
1986 unix_state_unlock(other);
1987 kfree_skb(skb);
1988pipe_err:
1989 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1990 send_sig(SIGPIPE, current, 0);
1991 err = -EPIPE;
1992out_err:
1993 scm_destroy(&scm);
1994 return sent ? : err;
1995}
1996
1997static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
1998 int offset, size_t size, int flags)
1999{
2000 int err;
2001 bool send_sigpipe = false;
2002 bool init_scm = true;
2003 struct scm_cookie scm;
2004 struct sock *other, *sk = socket->sk;
2005 struct sk_buff *skb, *newskb = NULL, *tail = NULL;
2006
2007 if (flags & MSG_OOB)
2008 return -EOPNOTSUPP;
2009
2010 other = unix_peer(sk);
2011 if (!other || sk->sk_state != TCP_ESTABLISHED)
2012 return -ENOTCONN;
2013
2014 if (false) {
2015alloc_skb:
2016 unix_state_unlock(other);
2017 mutex_unlock(&unix_sk(other)->iolock);
2018 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
2019 &err, 0);
2020 if (!newskb)
2021 goto err;
2022 }
2023
2024 /* we must acquire iolock as we modify already present
2025 * skbs in the sk_receive_queue and mess with skb->len
2026 */
2027 err = mutex_lock_interruptible(&unix_sk(other)->iolock);
2028 if (err) {
2029 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
2030 goto err;
2031 }
2032
2033 if (sk->sk_shutdown & SEND_SHUTDOWN) {
2034 err = -EPIPE;
2035 send_sigpipe = true;
2036 goto err_unlock;
2037 }
2038
2039 unix_state_lock(other);
2040
2041 if (sock_flag(other, SOCK_DEAD) ||
2042 other->sk_shutdown & RCV_SHUTDOWN) {
2043 err = -EPIPE;
2044 send_sigpipe = true;
2045 goto err_state_unlock;
2046 }
2047
2048 if (init_scm) {
2049 err = maybe_init_creds(&scm, socket, other);
2050 if (err)
2051 goto err_state_unlock;
2052 init_scm = false;
2053 }
2054
2055 skb = skb_peek_tail(&other->sk_receive_queue);
2056 if (tail && tail == skb) {
2057 skb = newskb;
2058 } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
2059 if (newskb) {
2060 skb = newskb;
2061 } else {
2062 tail = skb;
2063 goto alloc_skb;
2064 }
2065 } else if (newskb) {
2066 /* this is fast path, we don't necessarily need to
2067 * call to kfree_skb even though with newskb == NULL
2068 * this - does no harm
2069 */
2070 consume_skb(newskb);
2071 newskb = NULL;
2072 }
2073
2074 if (skb_append_pagefrags(skb, page, offset, size)) {
2075 tail = skb;
2076 goto alloc_skb;
2077 }
2078
2079 skb->len += size;
2080 skb->data_len += size;
2081 skb->truesize += size;
2082 refcount_add(size, &sk->sk_wmem_alloc);
2083
2084 if (newskb) {
2085 err = unix_scm_to_skb(&scm, skb, false);
2086 if (err)
2087 goto err_state_unlock;
2088 spin_lock(&other->sk_receive_queue.lock);
2089 __skb_queue_tail(&other->sk_receive_queue, newskb);
2090 spin_unlock(&other->sk_receive_queue.lock);
2091 }
2092
2093 unix_state_unlock(other);
2094 mutex_unlock(&unix_sk(other)->iolock);
2095
2096 other->sk_data_ready(other);
2097 scm_destroy(&scm);
2098 return size;
2099
2100err_state_unlock:
2101 unix_state_unlock(other);
2102err_unlock:
2103 mutex_unlock(&unix_sk(other)->iolock);
2104err:
2105 kfree_skb(newskb);
2106 if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2107 send_sig(SIGPIPE, current, 0);
2108 if (!init_scm)
2109 scm_destroy(&scm);
2110 return err;
2111}
2112
2113static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2114 size_t len)
2115{
2116 int err;
2117 struct sock *sk = sock->sk;
2118
2119 err = sock_error(sk);
2120 if (err)
2121 return err;
2122
2123 if (sk->sk_state != TCP_ESTABLISHED)
2124 return -ENOTCONN;
2125
2126 if (msg->msg_namelen)
2127 msg->msg_namelen = 0;
2128
2129 return unix_dgram_sendmsg(sock, msg, len);
2130}
2131
2132static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2133 size_t size, int flags)
2134{
2135 struct sock *sk = sock->sk;
2136
2137 if (sk->sk_state != TCP_ESTABLISHED)
2138 return -ENOTCONN;
2139
2140 return unix_dgram_recvmsg(sock, msg, size, flags);
2141}
2142
2143static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2144{
2145 struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
2146
2147 if (addr) {
2148 msg->msg_namelen = addr->len;
2149 memcpy(msg->msg_name, addr->name, addr->len);
2150 }
2151}
2152
2153static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
2154 size_t size, int flags)
2155{
2156 struct scm_cookie scm;
2157 struct sock *sk = sock->sk;
2158 struct unix_sock *u = unix_sk(sk);
2159 struct sk_buff *skb, *last;
2160 long timeo;
2161 int skip;
2162 int err;
2163
2164 err = -EOPNOTSUPP;
2165 if (flags&MSG_OOB)
2166 goto out;
2167
2168 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2169
2170 do {
2171 mutex_lock(&u->iolock);
2172
2173 skip = sk_peek_offset(sk, flags);
2174 skb = __skb_try_recv_datagram(sk, &sk->sk_receive_queue, flags,
2175 &skip, &err, &last);
2176 if (skb) {
2177 if (!(flags & MSG_PEEK))
2178 scm_stat_del(sk, skb);
2179 break;
2180 }
2181
2182 mutex_unlock(&u->iolock);
2183
2184 if (err != -EAGAIN)
2185 break;
2186 } while (timeo &&
2187 !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue,
2188 &err, &timeo, last));
2189
2190 if (!skb) { /* implies iolock unlocked */
2191 unix_state_lock(sk);
2192 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2193 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2194 (sk->sk_shutdown & RCV_SHUTDOWN))
2195 err = 0;
2196 unix_state_unlock(sk);
2197 goto out;
2198 }
2199
2200 if (wq_has_sleeper(&u->peer_wait))
2201 wake_up_interruptible_sync_poll(&u->peer_wait,
2202 EPOLLOUT | EPOLLWRNORM |
2203 EPOLLWRBAND);
2204
2205 if (msg->msg_name)
2206 unix_copy_addr(msg, skb->sk);
2207
2208 if (size > skb->len - skip)
2209 size = skb->len - skip;
2210 else if (size < skb->len - skip)
2211 msg->msg_flags |= MSG_TRUNC;
2212
2213 err = skb_copy_datagram_msg(skb, skip, msg, size);
2214 if (err)
2215 goto out_free;
2216
2217 if (sock_flag(sk, SOCK_RCVTSTAMP))
2218 __sock_recv_timestamp(msg, sk, skb);
2219
2220 memset(&scm, 0, sizeof(scm));
2221
2222 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2223 unix_set_secdata(&scm, skb);
2224
2225 if (!(flags & MSG_PEEK)) {
2226 if (UNIXCB(skb).fp)
2227 unix_detach_fds(&scm, skb);
2228
2229 sk_peek_offset_bwd(sk, skb->len);
2230 } else {
2231 /* It is questionable: on PEEK we could:
2232 - do not return fds - good, but too simple 8)
2233 - return fds, and do not return them on read (old strategy,
2234 apparently wrong)
2235 - clone fds (I chose it for now, it is the most universal
2236 solution)
2237
2238 POSIX 1003.1g does not actually define this clearly
2239 at all. POSIX 1003.1g doesn't define a lot of things
2240 clearly however!
2241
2242 */
2243
2244 sk_peek_offset_fwd(sk, size);
2245
2246 if (UNIXCB(skb).fp)
2247 unix_peek_fds(&scm, skb);
2248 }
2249 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2250
2251 scm_recv(sock, msg, &scm, flags);
2252
2253out_free:
2254 skb_free_datagram(sk, skb);
2255 mutex_unlock(&u->iolock);
2256out:
2257 return err;
2258}
2259
2260/*
2261 * Sleep until more data has arrived. But check for races..
2262 */
2263static long unix_stream_data_wait(struct sock *sk, long timeo,
2264 struct sk_buff *last, unsigned int last_len,
2265 bool freezable)
2266{
2267 struct sk_buff *tail;
2268 DEFINE_WAIT(wait);
2269
2270 unix_state_lock(sk);
2271
2272 for (;;) {
2273 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2274
2275 tail = skb_peek_tail(&sk->sk_receive_queue);
2276 if (tail != last ||
2277 (tail && tail->len != last_len) ||
2278 sk->sk_err ||
2279 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2280 signal_pending(current) ||
2281 !timeo)
2282 break;
2283
2284 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2285 unix_state_unlock(sk);
2286 if (freezable)
2287 timeo = freezable_schedule_timeout(timeo);
2288 else
2289 timeo = schedule_timeout(timeo);
2290 unix_state_lock(sk);
2291
2292 if (sock_flag(sk, SOCK_DEAD))
2293 break;
2294
2295 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2296 }
2297
2298 finish_wait(sk_sleep(sk), &wait);
2299 unix_state_unlock(sk);
2300 return timeo;
2301}
2302
2303static unsigned int unix_skb_len(const struct sk_buff *skb)
2304{
2305 return skb->len - UNIXCB(skb).consumed;
2306}
2307
2308struct unix_stream_read_state {
2309 int (*recv_actor)(struct sk_buff *, int, int,
2310 struct unix_stream_read_state *);
2311 struct socket *socket;
2312 struct msghdr *msg;
2313 struct pipe_inode_info *pipe;
2314 size_t size;
2315 int flags;
2316 unsigned int splice_flags;
2317};
2318
2319static int unix_stream_read_generic(struct unix_stream_read_state *state,
2320 bool freezable)
2321{
2322 struct scm_cookie scm;
2323 struct socket *sock = state->socket;
2324 struct sock *sk = sock->sk;
2325 struct unix_sock *u = unix_sk(sk);
2326 int copied = 0;
2327 int flags = state->flags;
2328 int noblock = flags & MSG_DONTWAIT;
2329 bool check_creds = false;
2330 int target;
2331 int err = 0;
2332 long timeo;
2333 int skip;
2334 size_t size = state->size;
2335 unsigned int last_len;
2336
2337 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2338 err = -EINVAL;
2339 goto out;
2340 }
2341
2342 if (unlikely(flags & MSG_OOB)) {
2343 err = -EOPNOTSUPP;
2344 goto out;
2345 }
2346
2347 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2348 timeo = sock_rcvtimeo(sk, noblock);
2349
2350 memset(&scm, 0, sizeof(scm));
2351
2352 /* Lock the socket to prevent queue disordering
2353 * while sleeps in memcpy_tomsg
2354 */
2355 mutex_lock(&u->iolock);
2356
2357 skip = max(sk_peek_offset(sk, flags), 0);
2358
2359 do {
2360 int chunk;
2361 bool drop_skb;
2362 struct sk_buff *skb, *last;
2363
2364redo:
2365 unix_state_lock(sk);
2366 if (sock_flag(sk, SOCK_DEAD)) {
2367 err = -ECONNRESET;
2368 goto unlock;
2369 }
2370 last = skb = skb_peek(&sk->sk_receive_queue);
2371 last_len = last ? last->len : 0;
2372again:
2373 if (skb == NULL) {
2374 if (copied >= target)
2375 goto unlock;
2376
2377 /*
2378 * POSIX 1003.1g mandates this order.
2379 */
2380
2381 err = sock_error(sk);
2382 if (err)
2383 goto unlock;
2384 if (sk->sk_shutdown & RCV_SHUTDOWN)
2385 goto unlock;
2386
2387 unix_state_unlock(sk);
2388 if (!timeo) {
2389 err = -EAGAIN;
2390 break;
2391 }
2392
2393 mutex_unlock(&u->iolock);
2394
2395 timeo = unix_stream_data_wait(sk, timeo, last,
2396 last_len, freezable);
2397
2398 if (signal_pending(current)) {
2399 err = sock_intr_errno(timeo);
2400 scm_destroy(&scm);
2401 goto out;
2402 }
2403
2404 mutex_lock(&u->iolock);
2405 goto redo;
2406unlock:
2407 unix_state_unlock(sk);
2408 break;
2409 }
2410
2411 while (skip >= unix_skb_len(skb)) {
2412 skip -= unix_skb_len(skb);
2413 last = skb;
2414 last_len = skb->len;
2415 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2416 if (!skb)
2417 goto again;
2418 }
2419
2420 unix_state_unlock(sk);
2421
2422 if (check_creds) {
2423 /* Never glue messages from different writers */
2424 if (!unix_skb_scm_eq(skb, &scm))
2425 break;
2426 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2427 /* Copy credentials */
2428 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2429 unix_set_secdata(&scm, skb);
2430 check_creds = true;
2431 }
2432
2433 /* Copy address just once */
2434 if (state->msg && state->msg->msg_name) {
2435 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2436 state->msg->msg_name);
2437 unix_copy_addr(state->msg, skb->sk);
2438 sunaddr = NULL;
2439 }
2440
2441 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2442 skb_get(skb);
2443 chunk = state->recv_actor(skb, skip, chunk, state);
2444 drop_skb = !unix_skb_len(skb);
2445 /* skb is only safe to use if !drop_skb */
2446 consume_skb(skb);
2447 if (chunk < 0) {
2448 if (copied == 0)
2449 copied = -EFAULT;
2450 break;
2451 }
2452 copied += chunk;
2453 size -= chunk;
2454
2455 if (drop_skb) {
2456 /* the skb was touched by a concurrent reader;
2457 * we should not expect anything from this skb
2458 * anymore and assume it invalid - we can be
2459 * sure it was dropped from the socket queue
2460 *
2461 * let's report a short read
2462 */
2463 err = 0;
2464 break;
2465 }
2466
2467 /* Mark read part of skb as used */
2468 if (!(flags & MSG_PEEK)) {
2469 UNIXCB(skb).consumed += chunk;
2470
2471 sk_peek_offset_bwd(sk, chunk);
2472
2473 if (UNIXCB(skb).fp) {
2474 scm_stat_del(sk, skb);
2475 unix_detach_fds(&scm, skb);
2476 }
2477
2478 if (unix_skb_len(skb))
2479 break;
2480
2481 skb_unlink(skb, &sk->sk_receive_queue);
2482 consume_skb(skb);
2483
2484 if (scm.fp)
2485 break;
2486 } else {
2487 /* It is questionable, see note in unix_dgram_recvmsg.
2488 */
2489 if (UNIXCB(skb).fp)
2490 unix_peek_fds(&scm, skb);
2491
2492 sk_peek_offset_fwd(sk, chunk);
2493
2494 if (UNIXCB(skb).fp)
2495 break;
2496
2497 skip = 0;
2498 last = skb;
2499 last_len = skb->len;
2500 unix_state_lock(sk);
2501 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2502 if (skb)
2503 goto again;
2504 unix_state_unlock(sk);
2505 break;
2506 }
2507 } while (size);
2508
2509 mutex_unlock(&u->iolock);
2510 if (state->msg)
2511 scm_recv(sock, state->msg, &scm, flags);
2512 else
2513 scm_destroy(&scm);
2514out:
2515 return copied ? : err;
2516}
2517
2518static int unix_stream_read_actor(struct sk_buff *skb,
2519 int skip, int chunk,
2520 struct unix_stream_read_state *state)
2521{
2522 int ret;
2523
2524 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2525 state->msg, chunk);
2526 return ret ?: chunk;
2527}
2528
2529static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2530 size_t size, int flags)
2531{
2532 struct unix_stream_read_state state = {
2533 .recv_actor = unix_stream_read_actor,
2534 .socket = sock,
2535 .msg = msg,
2536 .size = size,
2537 .flags = flags
2538 };
2539
2540 return unix_stream_read_generic(&state, true);
2541}
2542
2543static int unix_stream_splice_actor(struct sk_buff *skb,
2544 int skip, int chunk,
2545 struct unix_stream_read_state *state)
2546{
2547 return skb_splice_bits(skb, state->socket->sk,
2548 UNIXCB(skb).consumed + skip,
2549 state->pipe, chunk, state->splice_flags);
2550}
2551
2552static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2553 struct pipe_inode_info *pipe,
2554 size_t size, unsigned int flags)
2555{
2556 struct unix_stream_read_state state = {
2557 .recv_actor = unix_stream_splice_actor,
2558 .socket = sock,
2559 .pipe = pipe,
2560 .size = size,
2561 .splice_flags = flags,
2562 };
2563
2564 if (unlikely(*ppos))
2565 return -ESPIPE;
2566
2567 if (sock->file->f_flags & O_NONBLOCK ||
2568 flags & SPLICE_F_NONBLOCK)
2569 state.flags = MSG_DONTWAIT;
2570
2571 return unix_stream_read_generic(&state, false);
2572}
2573
2574static int unix_shutdown(struct socket *sock, int mode)
2575{
2576 struct sock *sk = sock->sk;
2577 struct sock *other;
2578
2579 if (mode < SHUT_RD || mode > SHUT_RDWR)
2580 return -EINVAL;
2581 /* This maps:
2582 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2583 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2584 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2585 */
2586 ++mode;
2587
2588 unix_state_lock(sk);
2589 sk->sk_shutdown |= mode;
2590 other = unix_peer(sk);
2591 if (other)
2592 sock_hold(other);
2593 unix_state_unlock(sk);
2594 sk->sk_state_change(sk);
2595
2596 if (other &&
2597 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2598
2599 int peer_mode = 0;
2600
2601 if (mode&RCV_SHUTDOWN)
2602 peer_mode |= SEND_SHUTDOWN;
2603 if (mode&SEND_SHUTDOWN)
2604 peer_mode |= RCV_SHUTDOWN;
2605 unix_state_lock(other);
2606 other->sk_shutdown |= peer_mode;
2607 unix_state_unlock(other);
2608 other->sk_state_change(other);
2609 if (peer_mode == SHUTDOWN_MASK)
2610 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2611 else if (peer_mode & RCV_SHUTDOWN)
2612 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2613 }
2614 if (other)
2615 sock_put(other);
2616
2617 return 0;
2618}
2619
2620long unix_inq_len(struct sock *sk)
2621{
2622 struct sk_buff *skb;
2623 long amount = 0;
2624
2625 if (sk->sk_state == TCP_LISTEN)
2626 return -EINVAL;
2627
2628 spin_lock(&sk->sk_receive_queue.lock);
2629 if (sk->sk_type == SOCK_STREAM ||
2630 sk->sk_type == SOCK_SEQPACKET) {
2631 skb_queue_walk(&sk->sk_receive_queue, skb)
2632 amount += unix_skb_len(skb);
2633 } else {
2634 skb = skb_peek(&sk->sk_receive_queue);
2635 if (skb)
2636 amount = skb->len;
2637 }
2638 spin_unlock(&sk->sk_receive_queue.lock);
2639
2640 return amount;
2641}
2642EXPORT_SYMBOL_GPL(unix_inq_len);
2643
2644long unix_outq_len(struct sock *sk)
2645{
2646 return sk_wmem_alloc_get(sk);
2647}
2648EXPORT_SYMBOL_GPL(unix_outq_len);
2649
2650static int unix_open_file(struct sock *sk)
2651{
2652 struct path path;
2653 struct file *f;
2654 int fd;
2655
2656 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
2657 return -EPERM;
2658
2659 if (!smp_load_acquire(&unix_sk(sk)->addr))
2660 return -ENOENT;
2661
2662 path = unix_sk(sk)->path;
2663 if (!path.dentry)
2664 return -ENOENT;
2665
2666 path_get(&path);
2667
2668 fd = get_unused_fd_flags(O_CLOEXEC);
2669 if (fd < 0)
2670 goto out;
2671
2672 f = dentry_open(&path, O_PATH, current_cred());
2673 if (IS_ERR(f)) {
2674 put_unused_fd(fd);
2675 fd = PTR_ERR(f);
2676 goto out;
2677 }
2678
2679 fd_install(fd, f);
2680out:
2681 path_put(&path);
2682
2683 return fd;
2684}
2685
2686static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2687{
2688 struct sock *sk = sock->sk;
2689 long amount = 0;
2690 int err;
2691
2692 switch (cmd) {
2693 case SIOCOUTQ:
2694 amount = unix_outq_len(sk);
2695 err = put_user(amount, (int __user *)arg);
2696 break;
2697 case SIOCINQ:
2698 amount = unix_inq_len(sk);
2699 if (amount < 0)
2700 err = amount;
2701 else
2702 err = put_user(amount, (int __user *)arg);
2703 break;
2704 case SIOCUNIXFILE:
2705 err = unix_open_file(sk);
2706 break;
2707 default:
2708 err = -ENOIOCTLCMD;
2709 break;
2710 }
2711 return err;
2712}
2713
2714#ifdef CONFIG_COMPAT
2715static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2716{
2717 return unix_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
2718}
2719#endif
2720
2721static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2722{
2723 struct sock *sk = sock->sk;
2724 __poll_t mask;
2725
2726 sock_poll_wait(file, sock, wait);
2727 mask = 0;
2728
2729 /* exceptional events? */
2730 if (sk->sk_err)
2731 mask |= EPOLLERR;
2732 if (sk->sk_shutdown == SHUTDOWN_MASK)
2733 mask |= EPOLLHUP;
2734 if (sk->sk_shutdown & RCV_SHUTDOWN)
2735 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2736
2737 /* readable? */
2738 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
2739 mask |= EPOLLIN | EPOLLRDNORM;
2740
2741 /* Connection-based need to check for termination and startup */
2742 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2743 sk->sk_state == TCP_CLOSE)
2744 mask |= EPOLLHUP;
2745
2746 /*
2747 * we set writable also when the other side has shut down the
2748 * connection. This prevents stuck sockets.
2749 */
2750 if (unix_writable(sk))
2751 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
2752
2753 return mask;
2754}
2755
2756static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
2757 poll_table *wait)
2758{
2759 struct sock *sk = sock->sk, *other;
2760 unsigned int writable;
2761 __poll_t mask;
2762
2763 sock_poll_wait(file, sock, wait);
2764 mask = 0;
2765
2766 /* exceptional events? */
2767 if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
2768 mask |= EPOLLERR |
2769 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
2770
2771 if (sk->sk_shutdown & RCV_SHUTDOWN)
2772 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2773 if (sk->sk_shutdown == SHUTDOWN_MASK)
2774 mask |= EPOLLHUP;
2775
2776 /* readable? */
2777 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
2778 mask |= EPOLLIN | EPOLLRDNORM;
2779
2780 /* Connection-based need to check for termination and startup */
2781 if (sk->sk_type == SOCK_SEQPACKET) {
2782 if (sk->sk_state == TCP_CLOSE)
2783 mask |= EPOLLHUP;
2784 /* connection hasn't started yet? */
2785 if (sk->sk_state == TCP_SYN_SENT)
2786 return mask;
2787 }
2788
2789 /* No write status requested, avoid expensive OUT tests. */
2790 if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT)))
2791 return mask;
2792
2793 writable = unix_writable(sk);
2794 if (writable) {
2795 unix_state_lock(sk);
2796
2797 other = unix_peer(sk);
2798 if (other && unix_peer(other) != sk &&
2799 unix_recvq_full_lockless(other) &&
2800 unix_dgram_peer_wake_me(sk, other))
2801 writable = 0;
2802
2803 unix_state_unlock(sk);
2804 }
2805
2806 if (writable)
2807 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
2808 else
2809 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2810
2811 return mask;
2812}
2813
2814#ifdef CONFIG_PROC_FS
2815
2816#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2817
2818#define get_bucket(x) ((x) >> BUCKET_SPACE)
2819#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2820#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2821
2822static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2823{
2824 unsigned long offset = get_offset(*pos);
2825 unsigned long bucket = get_bucket(*pos);
2826 struct sock *sk;
2827 unsigned long count = 0;
2828
2829 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2830 if (sock_net(sk) != seq_file_net(seq))
2831 continue;
2832 if (++count == offset)
2833 break;
2834 }
2835
2836 return sk;
2837}
2838
2839static struct sock *unix_next_socket(struct seq_file *seq,
2840 struct sock *sk,
2841 loff_t *pos)
2842{
2843 unsigned long bucket;
2844
2845 while (sk > (struct sock *)SEQ_START_TOKEN) {
2846 sk = sk_next(sk);
2847 if (!sk)
2848 goto next_bucket;
2849 if (sock_net(sk) == seq_file_net(seq))
2850 return sk;
2851 }
2852
2853 do {
2854 sk = unix_from_bucket(seq, pos);
2855 if (sk)
2856 return sk;
2857
2858next_bucket:
2859 bucket = get_bucket(*pos) + 1;
2860 *pos = set_bucket_offset(bucket, 1);
2861 } while (bucket < ARRAY_SIZE(unix_socket_table));
2862
2863 return NULL;
2864}
2865
2866static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2867 __acquires(unix_table_lock)
2868{
2869 spin_lock(&unix_table_lock);
2870
2871 if (!*pos)
2872 return SEQ_START_TOKEN;
2873
2874 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2875 return NULL;
2876
2877 return unix_next_socket(seq, NULL, pos);
2878}
2879
2880static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2881{
2882 ++*pos;
2883 return unix_next_socket(seq, v, pos);
2884}
2885
2886static void unix_seq_stop(struct seq_file *seq, void *v)
2887 __releases(unix_table_lock)
2888{
2889 spin_unlock(&unix_table_lock);
2890}
2891
2892static int unix_seq_show(struct seq_file *seq, void *v)
2893{
2894
2895 if (v == SEQ_START_TOKEN)
2896 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2897 "Inode Path\n");
2898 else {
2899 struct sock *s = v;
2900 struct unix_sock *u = unix_sk(s);
2901 unix_state_lock(s);
2902
2903 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2904 s,
2905 refcount_read(&s->sk_refcnt),
2906 0,
2907 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2908 s->sk_type,
2909 s->sk_socket ?
2910 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2911 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2912 sock_i_ino(s));
2913
2914 if (u->addr) { // under unix_table_lock here
2915 int i, len;
2916 seq_putc(seq, ' ');
2917
2918 i = 0;
2919 len = u->addr->len - sizeof(short);
2920 if (!UNIX_ABSTRACT(s))
2921 len--;
2922 else {
2923 seq_putc(seq, '@');
2924 i++;
2925 }
2926 for ( ; i < len; i++)
2927 seq_putc(seq, u->addr->name->sun_path[i] ?:
2928 '@');
2929 }
2930 unix_state_unlock(s);
2931 seq_putc(seq, '\n');
2932 }
2933
2934 return 0;
2935}
2936
2937static const struct seq_operations unix_seq_ops = {
2938 .start = unix_seq_start,
2939 .next = unix_seq_next,
2940 .stop = unix_seq_stop,
2941 .show = unix_seq_show,
2942};
2943#endif
2944
2945static const struct net_proto_family unix_family_ops = {
2946 .family = PF_UNIX,
2947 .create = unix_create,
2948 .owner = THIS_MODULE,
2949};
2950
2951
2952static int __net_init unix_net_init(struct net *net)
2953{
2954 int error = -ENOMEM;
2955
2956 net->unx.sysctl_max_dgram_qlen = 10;
2957 if (unix_sysctl_register(net))
2958 goto out;
2959
2960#ifdef CONFIG_PROC_FS
2961 if (!proc_create_net("unix", 0, net->proc_net, &unix_seq_ops,
2962 sizeof(struct seq_net_private))) {
2963 unix_sysctl_unregister(net);
2964 goto out;
2965 }
2966#endif
2967 error = 0;
2968out:
2969 return error;
2970}
2971
2972static void __net_exit unix_net_exit(struct net *net)
2973{
2974 unix_sysctl_unregister(net);
2975 remove_proc_entry("unix", net->proc_net);
2976}
2977
2978static struct pernet_operations unix_net_ops = {
2979 .init = unix_net_init,
2980 .exit = unix_net_exit,
2981};
2982
2983static int __init af_unix_init(void)
2984{
2985 int rc = -1;
2986
2987 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb));
2988
2989 rc = proto_register(&unix_proto, 1);
2990 if (rc != 0) {
2991 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
2992 goto out;
2993 }
2994
2995 sock_register(&unix_family_ops);
2996 register_pernet_subsys(&unix_net_ops);
2997out:
2998 return rc;
2999}
3000
3001static void __exit af_unix_exit(void)
3002{
3003 sock_unregister(PF_UNIX);
3004 proto_unregister(&unix_proto);
3005 unregister_pernet_subsys(&unix_net_ops);
3006}
3007
3008/* Earlier than device_initcall() so that other drivers invoking
3009 request_module() don't end up in a loop when modprobe tries
3010 to use a UNIX socket. But later than subsys_initcall() because
3011 we depend on stuff initialised there */
3012fs_initcall(af_unix_init);
3013module_exit(af_unix_exit);
3014
3015MODULE_LICENSE("GPL");
3016MODULE_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
118static struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
119static DEFINE_SPINLOCK(unix_table_lock);
120static atomic_long_t unix_nr_socks;
121
122#define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE])
123
124#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
125
126#ifdef CONFIG_SECURITY_NETWORK
127static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
128{
129 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
130}
131
132static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
133{
134 scm->secid = *UNIXSID(skb);
135}
136#else
137static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
138{ }
139
140static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
141{ }
142#endif /* CONFIG_SECURITY_NETWORK */
143
144/*
145 * SMP locking strategy:
146 * hash table is protected with spinlock unix_table_lock
147 * each socket state is protected by separate spin lock.
148 */
149
150static inline unsigned unix_hash_fold(__wsum n)
151{
152 unsigned hash = (__force unsigned)n;
153 hash ^= hash>>16;
154 hash ^= hash>>8;
155 return hash&(UNIX_HASH_SIZE-1);
156}
157
158#define unix_peer(sk) (unix_sk(sk)->peer)
159
160static inline int unix_our_peer(struct sock *sk, struct sock *osk)
161{
162 return unix_peer(osk) == sk;
163}
164
165static inline int unix_may_send(struct sock *sk, struct sock *osk)
166{
167 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
168}
169
170static inline int unix_recvq_full(struct sock const *sk)
171{
172 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
173}
174
175static struct sock *unix_peer_get(struct sock *s)
176{
177 struct sock *peer;
178
179 unix_state_lock(s);
180 peer = unix_peer(s);
181 if (peer)
182 sock_hold(peer);
183 unix_state_unlock(s);
184 return peer;
185}
186
187static inline void unix_release_addr(struct unix_address *addr)
188{
189 if (atomic_dec_and_test(&addr->refcnt))
190 kfree(addr);
191}
192
193/*
194 * Check unix socket name:
195 * - should be not zero length.
196 * - if started by not zero, should be NULL terminated (FS object)
197 * - if started by zero, it is abstract name.
198 */
199
200static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned *hashp)
201{
202 if (len <= sizeof(short) || len > sizeof(*sunaddr))
203 return -EINVAL;
204 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
205 return -EINVAL;
206 if (sunaddr->sun_path[0]) {
207 /*
208 * This may look like an off by one error but it is a bit more
209 * subtle. 108 is the longest valid AF_UNIX path for a binding.
210 * sun_path[108] doesn't as such exist. However in kernel space
211 * we are guaranteed that it is a valid memory location in our
212 * kernel address buffer.
213 */
214 ((char *)sunaddr)[len] = 0;
215 len = strlen(sunaddr->sun_path)+1+sizeof(short);
216 return len;
217 }
218
219 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
220 return len;
221}
222
223static void __unix_remove_socket(struct sock *sk)
224{
225 sk_del_node_init(sk);
226}
227
228static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
229{
230 WARN_ON(!sk_unhashed(sk));
231 sk_add_node(sk, list);
232}
233
234static inline void unix_remove_socket(struct sock *sk)
235{
236 spin_lock(&unix_table_lock);
237 __unix_remove_socket(sk);
238 spin_unlock(&unix_table_lock);
239}
240
241static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
242{
243 spin_lock(&unix_table_lock);
244 __unix_insert_socket(list, sk);
245 spin_unlock(&unix_table_lock);
246}
247
248static struct sock *__unix_find_socket_byname(struct net *net,
249 struct sockaddr_un *sunname,
250 int len, int type, unsigned hash)
251{
252 struct sock *s;
253 struct hlist_node *node;
254
255 sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
256 struct unix_sock *u = unix_sk(s);
257
258 if (!net_eq(sock_net(s), net))
259 continue;
260
261 if (u->addr->len == len &&
262 !memcmp(u->addr->name, sunname, len))
263 goto found;
264 }
265 s = NULL;
266found:
267 return s;
268}
269
270static inline struct sock *unix_find_socket_byname(struct net *net,
271 struct sockaddr_un *sunname,
272 int len, int type,
273 unsigned hash)
274{
275 struct sock *s;
276
277 spin_lock(&unix_table_lock);
278 s = __unix_find_socket_byname(net, sunname, len, type, hash);
279 if (s)
280 sock_hold(s);
281 spin_unlock(&unix_table_lock);
282 return s;
283}
284
285static struct sock *unix_find_socket_byinode(struct inode *i)
286{
287 struct sock *s;
288 struct hlist_node *node;
289
290 spin_lock(&unix_table_lock);
291 sk_for_each(s, node,
292 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
293 struct dentry *dentry = unix_sk(s)->dentry;
294
295 if (dentry && dentry->d_inode == i) {
296 sock_hold(s);
297 goto found;
298 }
299 }
300 s = NULL;
301found:
302 spin_unlock(&unix_table_lock);
303 return s;
304}
305
306static inline int unix_writable(struct sock *sk)
307{
308 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
309}
310
311static void unix_write_space(struct sock *sk)
312{
313 struct socket_wq *wq;
314
315 rcu_read_lock();
316 if (unix_writable(sk)) {
317 wq = rcu_dereference(sk->sk_wq);
318 if (wq_has_sleeper(wq))
319 wake_up_interruptible_sync_poll(&wq->wait,
320 POLLOUT | POLLWRNORM | POLLWRBAND);
321 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
322 }
323 rcu_read_unlock();
324}
325
326/* When dgram socket disconnects (or changes its peer), we clear its receive
327 * queue of packets arrived from previous peer. First, it allows to do
328 * flow control based only on wmem_alloc; second, sk connected to peer
329 * may receive messages only from that peer. */
330static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
331{
332 if (!skb_queue_empty(&sk->sk_receive_queue)) {
333 skb_queue_purge(&sk->sk_receive_queue);
334 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
335
336 /* If one link of bidirectional dgram pipe is disconnected,
337 * we signal error. Messages are lost. Do not make this,
338 * when peer was not connected to us.
339 */
340 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
341 other->sk_err = ECONNRESET;
342 other->sk_error_report(other);
343 }
344 }
345}
346
347static void unix_sock_destructor(struct sock *sk)
348{
349 struct unix_sock *u = unix_sk(sk);
350
351 skb_queue_purge(&sk->sk_receive_queue);
352
353 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
354 WARN_ON(!sk_unhashed(sk));
355 WARN_ON(sk->sk_socket);
356 if (!sock_flag(sk, SOCK_DEAD)) {
357 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk);
358 return;
359 }
360
361 if (u->addr)
362 unix_release_addr(u->addr);
363
364 atomic_long_dec(&unix_nr_socks);
365 local_bh_disable();
366 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
367 local_bh_enable();
368#ifdef UNIX_REFCNT_DEBUG
369 printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk,
370 atomic_long_read(&unix_nr_socks));
371#endif
372}
373
374static int unix_release_sock(struct sock *sk, int embrion)
375{
376 struct unix_sock *u = unix_sk(sk);
377 struct dentry *dentry;
378 struct vfsmount *mnt;
379 struct sock *skpair;
380 struct sk_buff *skb;
381 int state;
382
383 unix_remove_socket(sk);
384
385 /* Clear state */
386 unix_state_lock(sk);
387 sock_orphan(sk);
388 sk->sk_shutdown = SHUTDOWN_MASK;
389 dentry = u->dentry;
390 u->dentry = NULL;
391 mnt = u->mnt;
392 u->mnt = NULL;
393 state = sk->sk_state;
394 sk->sk_state = TCP_CLOSE;
395 unix_state_unlock(sk);
396
397 wake_up_interruptible_all(&u->peer_wait);
398
399 skpair = unix_peer(sk);
400
401 if (skpair != NULL) {
402 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
403 unix_state_lock(skpair);
404 /* No more writes */
405 skpair->sk_shutdown = SHUTDOWN_MASK;
406 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
407 skpair->sk_err = ECONNRESET;
408 unix_state_unlock(skpair);
409 skpair->sk_state_change(skpair);
410 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
411 }
412 sock_put(skpair); /* It may now die */
413 unix_peer(sk) = NULL;
414 }
415
416 /* Try to flush out this socket. Throw out buffers at least */
417
418 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
419 if (state == TCP_LISTEN)
420 unix_release_sock(skb->sk, 1);
421 /* passed fds are erased in the kfree_skb hook */
422 kfree_skb(skb);
423 }
424
425 if (dentry) {
426 dput(dentry);
427 mntput(mnt);
428 }
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 const struct proto_ops unix_stream_ops = {
531 .family = PF_UNIX,
532 .owner = THIS_MODULE,
533 .release = unix_release,
534 .bind = unix_bind,
535 .connect = unix_stream_connect,
536 .socketpair = unix_socketpair,
537 .accept = unix_accept,
538 .getname = unix_getname,
539 .poll = unix_poll,
540 .ioctl = unix_ioctl,
541 .listen = unix_listen,
542 .shutdown = unix_shutdown,
543 .setsockopt = sock_no_setsockopt,
544 .getsockopt = sock_no_getsockopt,
545 .sendmsg = unix_stream_sendmsg,
546 .recvmsg = unix_stream_recvmsg,
547 .mmap = sock_no_mmap,
548 .sendpage = sock_no_sendpage,
549};
550
551static const struct proto_ops unix_dgram_ops = {
552 .family = PF_UNIX,
553 .owner = THIS_MODULE,
554 .release = unix_release,
555 .bind = unix_bind,
556 .connect = unix_dgram_connect,
557 .socketpair = unix_socketpair,
558 .accept = sock_no_accept,
559 .getname = unix_getname,
560 .poll = unix_dgram_poll,
561 .ioctl = unix_ioctl,
562 .listen = sock_no_listen,
563 .shutdown = unix_shutdown,
564 .setsockopt = sock_no_setsockopt,
565 .getsockopt = sock_no_getsockopt,
566 .sendmsg = unix_dgram_sendmsg,
567 .recvmsg = unix_dgram_recvmsg,
568 .mmap = sock_no_mmap,
569 .sendpage = sock_no_sendpage,
570};
571
572static const struct proto_ops unix_seqpacket_ops = {
573 .family = PF_UNIX,
574 .owner = THIS_MODULE,
575 .release = unix_release,
576 .bind = unix_bind,
577 .connect = unix_stream_connect,
578 .socketpair = unix_socketpair,
579 .accept = unix_accept,
580 .getname = unix_getname,
581 .poll = unix_dgram_poll,
582 .ioctl = unix_ioctl,
583 .listen = unix_listen,
584 .shutdown = unix_shutdown,
585 .setsockopt = sock_no_setsockopt,
586 .getsockopt = sock_no_getsockopt,
587 .sendmsg = unix_seqpacket_sendmsg,
588 .recvmsg = unix_seqpacket_recvmsg,
589 .mmap = sock_no_mmap,
590 .sendpage = sock_no_sendpage,
591};
592
593static struct proto unix_proto = {
594 .name = "UNIX",
595 .owner = THIS_MODULE,
596 .obj_size = sizeof(struct unix_sock),
597};
598
599/*
600 * AF_UNIX sockets do not interact with hardware, hence they
601 * dont trigger interrupts - so it's safe for them to have
602 * bh-unsafe locking for their sk_receive_queue.lock. Split off
603 * this special lock-class by reinitializing the spinlock key:
604 */
605static struct lock_class_key af_unix_sk_receive_queue_lock_key;
606
607static struct sock *unix_create1(struct net *net, struct socket *sock)
608{
609 struct sock *sk = NULL;
610 struct unix_sock *u;
611
612 atomic_long_inc(&unix_nr_socks);
613 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
614 goto out;
615
616 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
617 if (!sk)
618 goto out;
619
620 sock_init_data(sock, sk);
621 lockdep_set_class(&sk->sk_receive_queue.lock,
622 &af_unix_sk_receive_queue_lock_key);
623
624 sk->sk_write_space = unix_write_space;
625 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
626 sk->sk_destruct = unix_sock_destructor;
627 u = unix_sk(sk);
628 u->dentry = NULL;
629 u->mnt = NULL;
630 spin_lock_init(&u->lock);
631 atomic_long_set(&u->inflight, 0);
632 INIT_LIST_HEAD(&u->link);
633 mutex_init(&u->readlock); /* single task reading lock */
634 init_waitqueue_head(&u->peer_wait);
635 unix_insert_socket(unix_sockets_unbound, sk);
636out:
637 if (sk == NULL)
638 atomic_long_dec(&unix_nr_socks);
639 else {
640 local_bh_disable();
641 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
642 local_bh_enable();
643 }
644 return sk;
645}
646
647static int unix_create(struct net *net, struct socket *sock, int protocol,
648 int kern)
649{
650 if (protocol && protocol != PF_UNIX)
651 return -EPROTONOSUPPORT;
652
653 sock->state = SS_UNCONNECTED;
654
655 switch (sock->type) {
656 case SOCK_STREAM:
657 sock->ops = &unix_stream_ops;
658 break;
659 /*
660 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
661 * nothing uses it.
662 */
663 case SOCK_RAW:
664 sock->type = SOCK_DGRAM;
665 case SOCK_DGRAM:
666 sock->ops = &unix_dgram_ops;
667 break;
668 case SOCK_SEQPACKET:
669 sock->ops = &unix_seqpacket_ops;
670 break;
671 default:
672 return -ESOCKTNOSUPPORT;
673 }
674
675 return unix_create1(net, sock) ? 0 : -ENOMEM;
676}
677
678static int unix_release(struct socket *sock)
679{
680 struct sock *sk = sock->sk;
681
682 if (!sk)
683 return 0;
684
685 sock->sk = NULL;
686
687 return unix_release_sock(sk, 0);
688}
689
690static int unix_autobind(struct socket *sock)
691{
692 struct sock *sk = sock->sk;
693 struct net *net = sock_net(sk);
694 struct unix_sock *u = unix_sk(sk);
695 static u32 ordernum = 1;
696 struct unix_address *addr;
697 int err;
698 unsigned int retries = 0;
699
700 mutex_lock(&u->readlock);
701
702 err = 0;
703 if (u->addr)
704 goto out;
705
706 err = -ENOMEM;
707 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
708 if (!addr)
709 goto out;
710
711 addr->name->sun_family = AF_UNIX;
712 atomic_set(&addr->refcnt, 1);
713
714retry:
715 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
716 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
717
718 spin_lock(&unix_table_lock);
719 ordernum = (ordernum+1)&0xFFFFF;
720
721 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
722 addr->hash)) {
723 spin_unlock(&unix_table_lock);
724 /*
725 * __unix_find_socket_byname() may take long time if many names
726 * are already in use.
727 */
728 cond_resched();
729 /* Give up if all names seems to be in use. */
730 if (retries++ == 0xFFFFF) {
731 err = -ENOSPC;
732 kfree(addr);
733 goto out;
734 }
735 goto retry;
736 }
737 addr->hash ^= sk->sk_type;
738
739 __unix_remove_socket(sk);
740 u->addr = addr;
741 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
742 spin_unlock(&unix_table_lock);
743 err = 0;
744
745out: mutex_unlock(&u->readlock);
746 return err;
747}
748
749static struct sock *unix_find_other(struct net *net,
750 struct sockaddr_un *sunname, int len,
751 int type, unsigned hash, int *error)
752{
753 struct sock *u;
754 struct path path;
755 int err = 0;
756
757 if (sunname->sun_path[0]) {
758 struct inode *inode;
759 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
760 if (err)
761 goto fail;
762 inode = path.dentry->d_inode;
763 err = inode_permission(inode, MAY_WRITE);
764 if (err)
765 goto put_fail;
766
767 err = -ECONNREFUSED;
768 if (!S_ISSOCK(inode->i_mode))
769 goto put_fail;
770 u = unix_find_socket_byinode(inode);
771 if (!u)
772 goto put_fail;
773
774 if (u->sk_type == type)
775 touch_atime(path.mnt, path.dentry);
776
777 path_put(&path);
778
779 err = -EPROTOTYPE;
780 if (u->sk_type != type) {
781 sock_put(u);
782 goto fail;
783 }
784 } else {
785 err = -ECONNREFUSED;
786 u = unix_find_socket_byname(net, sunname, len, type, hash);
787 if (u) {
788 struct dentry *dentry;
789 dentry = unix_sk(u)->dentry;
790 if (dentry)
791 touch_atime(unix_sk(u)->mnt, dentry);
792 } else
793 goto fail;
794 }
795 return u;
796
797put_fail:
798 path_put(&path);
799fail:
800 *error = err;
801 return NULL;
802}
803
804
805static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
806{
807 struct sock *sk = sock->sk;
808 struct net *net = sock_net(sk);
809 struct unix_sock *u = unix_sk(sk);
810 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
811 char *sun_path = sunaddr->sun_path;
812 struct dentry *dentry = NULL;
813 struct path path;
814 int err;
815 unsigned hash;
816 struct unix_address *addr;
817 struct hlist_head *list;
818
819 err = -EINVAL;
820 if (sunaddr->sun_family != AF_UNIX)
821 goto out;
822
823 if (addr_len == sizeof(short)) {
824 err = unix_autobind(sock);
825 goto out;
826 }
827
828 err = unix_mkname(sunaddr, addr_len, &hash);
829 if (err < 0)
830 goto out;
831 addr_len = err;
832
833 mutex_lock(&u->readlock);
834
835 err = -EINVAL;
836 if (u->addr)
837 goto out_up;
838
839 err = -ENOMEM;
840 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
841 if (!addr)
842 goto out_up;
843
844 memcpy(addr->name, sunaddr, addr_len);
845 addr->len = addr_len;
846 addr->hash = hash ^ sk->sk_type;
847 atomic_set(&addr->refcnt, 1);
848
849 if (sun_path[0]) {
850 unsigned int mode;
851 err = 0;
852 /*
853 * Get the parent directory, calculate the hash for last
854 * component.
855 */
856 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
857 err = PTR_ERR(dentry);
858 if (IS_ERR(dentry))
859 goto out_mknod_parent;
860
861 /*
862 * All right, let's create it.
863 */
864 mode = S_IFSOCK |
865 (SOCK_INODE(sock)->i_mode & ~current_umask());
866 err = mnt_want_write(path.mnt);
867 if (err)
868 goto out_mknod_dput;
869 err = security_path_mknod(&path, dentry, mode, 0);
870 if (err)
871 goto out_mknod_drop_write;
872 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
873out_mknod_drop_write:
874 mnt_drop_write(path.mnt);
875 if (err)
876 goto out_mknod_dput;
877 mutex_unlock(&path.dentry->d_inode->i_mutex);
878 dput(path.dentry);
879 path.dentry = dentry;
880
881 addr->hash = UNIX_HASH_SIZE;
882 }
883
884 spin_lock(&unix_table_lock);
885
886 if (!sun_path[0]) {
887 err = -EADDRINUSE;
888 if (__unix_find_socket_byname(net, sunaddr, addr_len,
889 sk->sk_type, hash)) {
890 unix_release_addr(addr);
891 goto out_unlock;
892 }
893
894 list = &unix_socket_table[addr->hash];
895 } else {
896 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
897 u->dentry = path.dentry;
898 u->mnt = path.mnt;
899 }
900
901 err = 0;
902 __unix_remove_socket(sk);
903 u->addr = addr;
904 __unix_insert_socket(list, sk);
905
906out_unlock:
907 spin_unlock(&unix_table_lock);
908out_up:
909 mutex_unlock(&u->readlock);
910out:
911 return err;
912
913out_mknod_dput:
914 dput(dentry);
915 mutex_unlock(&path.dentry->d_inode->i_mutex);
916 path_put(&path);
917out_mknod_parent:
918 if (err == -EEXIST)
919 err = -EADDRINUSE;
920 unix_release_addr(addr);
921 goto out_up;
922}
923
924static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
925{
926 if (unlikely(sk1 == sk2) || !sk2) {
927 unix_state_lock(sk1);
928 return;
929 }
930 if (sk1 < sk2) {
931 unix_state_lock(sk1);
932 unix_state_lock_nested(sk2);
933 } else {
934 unix_state_lock(sk2);
935 unix_state_lock_nested(sk1);
936 }
937}
938
939static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
940{
941 if (unlikely(sk1 == sk2) || !sk2) {
942 unix_state_unlock(sk1);
943 return;
944 }
945 unix_state_unlock(sk1);
946 unix_state_unlock(sk2);
947}
948
949static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
950 int alen, int flags)
951{
952 struct sock *sk = sock->sk;
953 struct net *net = sock_net(sk);
954 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
955 struct sock *other;
956 unsigned hash;
957 int err;
958
959 if (addr->sa_family != AF_UNSPEC) {
960 err = unix_mkname(sunaddr, alen, &hash);
961 if (err < 0)
962 goto out;
963 alen = err;
964
965 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
966 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
967 goto out;
968
969restart:
970 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
971 if (!other)
972 goto out;
973
974 unix_state_double_lock(sk, other);
975
976 /* Apparently VFS overslept socket death. Retry. */
977 if (sock_flag(other, SOCK_DEAD)) {
978 unix_state_double_unlock(sk, other);
979 sock_put(other);
980 goto restart;
981 }
982
983 err = -EPERM;
984 if (!unix_may_send(sk, other))
985 goto out_unlock;
986
987 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
988 if (err)
989 goto out_unlock;
990
991 } else {
992 /*
993 * 1003.1g breaking connected state with AF_UNSPEC
994 */
995 other = NULL;
996 unix_state_double_lock(sk, other);
997 }
998
999 /*
1000 * If it was connected, reconnect.
1001 */
1002 if (unix_peer(sk)) {
1003 struct sock *old_peer = unix_peer(sk);
1004 unix_peer(sk) = other;
1005 unix_state_double_unlock(sk, other);
1006
1007 if (other != old_peer)
1008 unix_dgram_disconnected(sk, old_peer);
1009 sock_put(old_peer);
1010 } else {
1011 unix_peer(sk) = other;
1012 unix_state_double_unlock(sk, other);
1013 }
1014 return 0;
1015
1016out_unlock:
1017 unix_state_double_unlock(sk, other);
1018 sock_put(other);
1019out:
1020 return err;
1021}
1022
1023static long unix_wait_for_peer(struct sock *other, long timeo)
1024{
1025 struct unix_sock *u = unix_sk(other);
1026 int sched;
1027 DEFINE_WAIT(wait);
1028
1029 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1030
1031 sched = !sock_flag(other, SOCK_DEAD) &&
1032 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1033 unix_recvq_full(other);
1034
1035 unix_state_unlock(other);
1036
1037 if (sched)
1038 timeo = schedule_timeout(timeo);
1039
1040 finish_wait(&u->peer_wait, &wait);
1041 return timeo;
1042}
1043
1044static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1045 int addr_len, int flags)
1046{
1047 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1048 struct sock *sk = sock->sk;
1049 struct net *net = sock_net(sk);
1050 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1051 struct sock *newsk = NULL;
1052 struct sock *other = NULL;
1053 struct sk_buff *skb = NULL;
1054 unsigned hash;
1055 int st;
1056 int err;
1057 long timeo;
1058
1059 err = unix_mkname(sunaddr, addr_len, &hash);
1060 if (err < 0)
1061 goto out;
1062 addr_len = err;
1063
1064 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1065 (err = unix_autobind(sock)) != 0)
1066 goto out;
1067
1068 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1069
1070 /* First of all allocate resources.
1071 If we will make it after state is locked,
1072 we will have to recheck all again in any case.
1073 */
1074
1075 err = -ENOMEM;
1076
1077 /* create new sock for complete connection */
1078 newsk = unix_create1(sock_net(sk), NULL);
1079 if (newsk == NULL)
1080 goto out;
1081
1082 /* Allocate skb for sending to listening sock */
1083 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1084 if (skb == NULL)
1085 goto out;
1086
1087restart:
1088 /* Find listening sock. */
1089 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1090 if (!other)
1091 goto out;
1092
1093 /* Latch state of peer */
1094 unix_state_lock(other);
1095
1096 /* Apparently VFS overslept socket death. Retry. */
1097 if (sock_flag(other, SOCK_DEAD)) {
1098 unix_state_unlock(other);
1099 sock_put(other);
1100 goto restart;
1101 }
1102
1103 err = -ECONNREFUSED;
1104 if (other->sk_state != TCP_LISTEN)
1105 goto out_unlock;
1106 if (other->sk_shutdown & RCV_SHUTDOWN)
1107 goto out_unlock;
1108
1109 if (unix_recvq_full(other)) {
1110 err = -EAGAIN;
1111 if (!timeo)
1112 goto out_unlock;
1113
1114 timeo = unix_wait_for_peer(other, timeo);
1115
1116 err = sock_intr_errno(timeo);
1117 if (signal_pending(current))
1118 goto out;
1119 sock_put(other);
1120 goto restart;
1121 }
1122
1123 /* Latch our state.
1124
1125 It is tricky place. We need to grab our state lock and cannot
1126 drop lock on peer. It is dangerous because deadlock is
1127 possible. Connect to self case and simultaneous
1128 attempt to connect are eliminated by checking socket
1129 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1130 check this before attempt to grab lock.
1131
1132 Well, and we have to recheck the state after socket locked.
1133 */
1134 st = sk->sk_state;
1135
1136 switch (st) {
1137 case TCP_CLOSE:
1138 /* This is ok... continue with connect */
1139 break;
1140 case TCP_ESTABLISHED:
1141 /* Socket is already connected */
1142 err = -EISCONN;
1143 goto out_unlock;
1144 default:
1145 err = -EINVAL;
1146 goto out_unlock;
1147 }
1148
1149 unix_state_lock_nested(sk);
1150
1151 if (sk->sk_state != st) {
1152 unix_state_unlock(sk);
1153 unix_state_unlock(other);
1154 sock_put(other);
1155 goto restart;
1156 }
1157
1158 err = security_unix_stream_connect(sk, other, newsk);
1159 if (err) {
1160 unix_state_unlock(sk);
1161 goto out_unlock;
1162 }
1163
1164 /* The way is open! Fastly set all the necessary fields... */
1165
1166 sock_hold(sk);
1167 unix_peer(newsk) = sk;
1168 newsk->sk_state = TCP_ESTABLISHED;
1169 newsk->sk_type = sk->sk_type;
1170 init_peercred(newsk);
1171 newu = unix_sk(newsk);
1172 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1173 otheru = unix_sk(other);
1174
1175 /* copy address information from listening to new sock*/
1176 if (otheru->addr) {
1177 atomic_inc(&otheru->addr->refcnt);
1178 newu->addr = otheru->addr;
1179 }
1180 if (otheru->dentry) {
1181 newu->dentry = dget(otheru->dentry);
1182 newu->mnt = mntget(otheru->mnt);
1183 }
1184
1185 /* Set credentials */
1186 copy_peercred(sk, other);
1187
1188 sock->state = SS_CONNECTED;
1189 sk->sk_state = TCP_ESTABLISHED;
1190 sock_hold(newsk);
1191
1192 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1193 unix_peer(sk) = newsk;
1194
1195 unix_state_unlock(sk);
1196
1197 /* take ten and and send info to listening sock */
1198 spin_lock(&other->sk_receive_queue.lock);
1199 __skb_queue_tail(&other->sk_receive_queue, skb);
1200 spin_unlock(&other->sk_receive_queue.lock);
1201 unix_state_unlock(other);
1202 other->sk_data_ready(other, 0);
1203 sock_put(other);
1204 return 0;
1205
1206out_unlock:
1207 if (other)
1208 unix_state_unlock(other);
1209
1210out:
1211 kfree_skb(skb);
1212 if (newsk)
1213 unix_release_sock(newsk, 0);
1214 if (other)
1215 sock_put(other);
1216 return err;
1217}
1218
1219static int unix_socketpair(struct socket *socka, struct socket *sockb)
1220{
1221 struct sock *ska = socka->sk, *skb = sockb->sk;
1222
1223 /* Join our sockets back to back */
1224 sock_hold(ska);
1225 sock_hold(skb);
1226 unix_peer(ska) = skb;
1227 unix_peer(skb) = ska;
1228 init_peercred(ska);
1229 init_peercred(skb);
1230
1231 if (ska->sk_type != SOCK_DGRAM) {
1232 ska->sk_state = TCP_ESTABLISHED;
1233 skb->sk_state = TCP_ESTABLISHED;
1234 socka->state = SS_CONNECTED;
1235 sockb->state = SS_CONNECTED;
1236 }
1237 return 0;
1238}
1239
1240static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1241{
1242 struct sock *sk = sock->sk;
1243 struct sock *tsk;
1244 struct sk_buff *skb;
1245 int err;
1246
1247 err = -EOPNOTSUPP;
1248 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1249 goto out;
1250
1251 err = -EINVAL;
1252 if (sk->sk_state != TCP_LISTEN)
1253 goto out;
1254
1255 /* If socket state is TCP_LISTEN it cannot change (for now...),
1256 * so that no locks are necessary.
1257 */
1258
1259 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1260 if (!skb) {
1261 /* This means receive shutdown. */
1262 if (err == 0)
1263 err = -EINVAL;
1264 goto out;
1265 }
1266
1267 tsk = skb->sk;
1268 skb_free_datagram(sk, skb);
1269 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1270
1271 /* attach accepted sock to socket */
1272 unix_state_lock(tsk);
1273 newsock->state = SS_CONNECTED;
1274 sock_graft(tsk, newsock);
1275 unix_state_unlock(tsk);
1276 return 0;
1277
1278out:
1279 return err;
1280}
1281
1282
1283static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1284{
1285 struct sock *sk = sock->sk;
1286 struct unix_sock *u;
1287 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1288 int err = 0;
1289
1290 if (peer) {
1291 sk = unix_peer_get(sk);
1292
1293 err = -ENOTCONN;
1294 if (!sk)
1295 goto out;
1296 err = 0;
1297 } else {
1298 sock_hold(sk);
1299 }
1300
1301 u = unix_sk(sk);
1302 unix_state_lock(sk);
1303 if (!u->addr) {
1304 sunaddr->sun_family = AF_UNIX;
1305 sunaddr->sun_path[0] = 0;
1306 *uaddr_len = sizeof(short);
1307 } else {
1308 struct unix_address *addr = u->addr;
1309
1310 *uaddr_len = addr->len;
1311 memcpy(sunaddr, addr->name, *uaddr_len);
1312 }
1313 unix_state_unlock(sk);
1314 sock_put(sk);
1315out:
1316 return err;
1317}
1318
1319static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1320{
1321 int i;
1322
1323 scm->fp = UNIXCB(skb).fp;
1324 UNIXCB(skb).fp = NULL;
1325
1326 for (i = scm->fp->count-1; i >= 0; i--)
1327 unix_notinflight(scm->fp->fp[i]);
1328}
1329
1330static void unix_destruct_scm(struct sk_buff *skb)
1331{
1332 struct scm_cookie scm;
1333 memset(&scm, 0, sizeof(scm));
1334 scm.pid = UNIXCB(skb).pid;
1335 scm.cred = UNIXCB(skb).cred;
1336 if (UNIXCB(skb).fp)
1337 unix_detach_fds(&scm, skb);
1338
1339 /* Alas, it calls VFS */
1340 /* So fscking what? fput() had been SMP-safe since the last Summer */
1341 scm_destroy(&scm);
1342 sock_wfree(skb);
1343}
1344
1345#define MAX_RECURSION_LEVEL 4
1346
1347static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1348{
1349 int i;
1350 unsigned char max_level = 0;
1351 int unix_sock_count = 0;
1352
1353 for (i = scm->fp->count - 1; i >= 0; i--) {
1354 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1355
1356 if (sk) {
1357 unix_sock_count++;
1358 max_level = max(max_level,
1359 unix_sk(sk)->recursion_level);
1360 }
1361 }
1362 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1363 return -ETOOMANYREFS;
1364
1365 /*
1366 * Need to duplicate file references for the sake of garbage
1367 * collection. Otherwise a socket in the fps might become a
1368 * candidate for GC while the skb is not yet queued.
1369 */
1370 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1371 if (!UNIXCB(skb).fp)
1372 return -ENOMEM;
1373
1374 if (unix_sock_count) {
1375 for (i = scm->fp->count - 1; i >= 0; i--)
1376 unix_inflight(scm->fp->fp[i]);
1377 }
1378 return max_level;
1379}
1380
1381static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1382{
1383 int err = 0;
1384 UNIXCB(skb).pid = get_pid(scm->pid);
1385 UNIXCB(skb).cred = get_cred(scm->cred);
1386 UNIXCB(skb).fp = NULL;
1387 if (scm->fp && send_fds)
1388 err = unix_attach_fds(scm, skb);
1389
1390 skb->destructor = unix_destruct_scm;
1391 return err;
1392}
1393
1394/*
1395 * Send AF_UNIX data.
1396 */
1397
1398static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1399 struct msghdr *msg, size_t len)
1400{
1401 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1402 struct sock *sk = sock->sk;
1403 struct net *net = sock_net(sk);
1404 struct unix_sock *u = unix_sk(sk);
1405 struct sockaddr_un *sunaddr = msg->msg_name;
1406 struct sock *other = NULL;
1407 int namelen = 0; /* fake GCC */
1408 int err;
1409 unsigned hash;
1410 struct sk_buff *skb;
1411 long timeo;
1412 struct scm_cookie tmp_scm;
1413 int max_level;
1414
1415 if (NULL == siocb->scm)
1416 siocb->scm = &tmp_scm;
1417 wait_for_unix_gc();
1418 err = scm_send(sock, msg, siocb->scm);
1419 if (err < 0)
1420 return err;
1421
1422 err = -EOPNOTSUPP;
1423 if (msg->msg_flags&MSG_OOB)
1424 goto out;
1425
1426 if (msg->msg_namelen) {
1427 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1428 if (err < 0)
1429 goto out;
1430 namelen = err;
1431 } else {
1432 sunaddr = NULL;
1433 err = -ENOTCONN;
1434 other = unix_peer_get(sk);
1435 if (!other)
1436 goto out;
1437 }
1438
1439 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1440 && (err = unix_autobind(sock)) != 0)
1441 goto out;
1442
1443 err = -EMSGSIZE;
1444 if (len > sk->sk_sndbuf - 32)
1445 goto out;
1446
1447 skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1448 if (skb == NULL)
1449 goto out;
1450
1451 err = unix_scm_to_skb(siocb->scm, skb, true);
1452 if (err < 0)
1453 goto out_free;
1454 max_level = err + 1;
1455 unix_get_secdata(siocb->scm, skb);
1456
1457 skb_reset_transport_header(skb);
1458 err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1459 if (err)
1460 goto out_free;
1461
1462 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1463
1464restart:
1465 if (!other) {
1466 err = -ECONNRESET;
1467 if (sunaddr == NULL)
1468 goto out_free;
1469
1470 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1471 hash, &err);
1472 if (other == NULL)
1473 goto out_free;
1474 }
1475
1476 if (sk_filter(other, skb) < 0) {
1477 /* Toss the packet but do not return any error to the sender */
1478 err = len;
1479 goto out_free;
1480 }
1481
1482 unix_state_lock(other);
1483 err = -EPERM;
1484 if (!unix_may_send(sk, other))
1485 goto out_unlock;
1486
1487 if (sock_flag(other, SOCK_DEAD)) {
1488 /*
1489 * Check with 1003.1g - what should
1490 * datagram error
1491 */
1492 unix_state_unlock(other);
1493 sock_put(other);
1494
1495 err = 0;
1496 unix_state_lock(sk);
1497 if (unix_peer(sk) == other) {
1498 unix_peer(sk) = NULL;
1499 unix_state_unlock(sk);
1500
1501 unix_dgram_disconnected(sk, other);
1502 sock_put(other);
1503 err = -ECONNREFUSED;
1504 } else {
1505 unix_state_unlock(sk);
1506 }
1507
1508 other = NULL;
1509 if (err)
1510 goto out_free;
1511 goto restart;
1512 }
1513
1514 err = -EPIPE;
1515 if (other->sk_shutdown & RCV_SHUTDOWN)
1516 goto out_unlock;
1517
1518 if (sk->sk_type != SOCK_SEQPACKET) {
1519 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1520 if (err)
1521 goto out_unlock;
1522 }
1523
1524 if (unix_peer(other) != sk && unix_recvq_full(other)) {
1525 if (!timeo) {
1526 err = -EAGAIN;
1527 goto out_unlock;
1528 }
1529
1530 timeo = unix_wait_for_peer(other, timeo);
1531
1532 err = sock_intr_errno(timeo);
1533 if (signal_pending(current))
1534 goto out_free;
1535
1536 goto restart;
1537 }
1538
1539 if (sock_flag(other, SOCK_RCVTSTAMP))
1540 __net_timestamp(skb);
1541 skb_queue_tail(&other->sk_receive_queue, skb);
1542 if (max_level > unix_sk(other)->recursion_level)
1543 unix_sk(other)->recursion_level = max_level;
1544 unix_state_unlock(other);
1545 other->sk_data_ready(other, len);
1546 sock_put(other);
1547 scm_destroy(siocb->scm);
1548 return len;
1549
1550out_unlock:
1551 unix_state_unlock(other);
1552out_free:
1553 kfree_skb(skb);
1554out:
1555 if (other)
1556 sock_put(other);
1557 scm_destroy(siocb->scm);
1558 return err;
1559}
1560
1561
1562static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1563 struct msghdr *msg, size_t len)
1564{
1565 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1566 struct sock *sk = sock->sk;
1567 struct sock *other = NULL;
1568 int err, size;
1569 struct sk_buff *skb;
1570 int sent = 0;
1571 struct scm_cookie tmp_scm;
1572 bool fds_sent = false;
1573 int max_level;
1574
1575 if (NULL == siocb->scm)
1576 siocb->scm = &tmp_scm;
1577 wait_for_unix_gc();
1578 err = scm_send(sock, msg, siocb->scm);
1579 if (err < 0)
1580 return err;
1581
1582 err = -EOPNOTSUPP;
1583 if (msg->msg_flags&MSG_OOB)
1584 goto out_err;
1585
1586 if (msg->msg_namelen) {
1587 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1588 goto out_err;
1589 } else {
1590 err = -ENOTCONN;
1591 other = unix_peer(sk);
1592 if (!other)
1593 goto out_err;
1594 }
1595
1596 if (sk->sk_shutdown & SEND_SHUTDOWN)
1597 goto pipe_err;
1598
1599 while (sent < len) {
1600 /*
1601 * Optimisation for the fact that under 0.01% of X
1602 * messages typically need breaking up.
1603 */
1604
1605 size = len-sent;
1606
1607 /* Keep two messages in the pipe so it schedules better */
1608 if (size > ((sk->sk_sndbuf >> 1) - 64))
1609 size = (sk->sk_sndbuf >> 1) - 64;
1610
1611 if (size > SKB_MAX_ALLOC)
1612 size = SKB_MAX_ALLOC;
1613
1614 /*
1615 * Grab a buffer
1616 */
1617
1618 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1619 &err);
1620
1621 if (skb == NULL)
1622 goto out_err;
1623
1624 /*
1625 * If you pass two values to the sock_alloc_send_skb
1626 * it tries to grab the large buffer with GFP_NOFS
1627 * (which can fail easily), and if it fails grab the
1628 * fallback size buffer which is under a page and will
1629 * succeed. [Alan]
1630 */
1631 size = min_t(int, size, skb_tailroom(skb));
1632
1633
1634 /* Only send the fds in the first buffer */
1635 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1636 if (err < 0) {
1637 kfree_skb(skb);
1638 goto out_err;
1639 }
1640 max_level = err + 1;
1641 fds_sent = true;
1642
1643 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1644 if (err) {
1645 kfree_skb(skb);
1646 goto out_err;
1647 }
1648
1649 unix_state_lock(other);
1650
1651 if (sock_flag(other, SOCK_DEAD) ||
1652 (other->sk_shutdown & RCV_SHUTDOWN))
1653 goto pipe_err_free;
1654
1655 skb_queue_tail(&other->sk_receive_queue, skb);
1656 if (max_level > unix_sk(other)->recursion_level)
1657 unix_sk(other)->recursion_level = max_level;
1658 unix_state_unlock(other);
1659 other->sk_data_ready(other, size);
1660 sent += size;
1661 }
1662
1663 scm_destroy(siocb->scm);
1664 siocb->scm = NULL;
1665
1666 return sent;
1667
1668pipe_err_free:
1669 unix_state_unlock(other);
1670 kfree_skb(skb);
1671pipe_err:
1672 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1673 send_sig(SIGPIPE, current, 0);
1674 err = -EPIPE;
1675out_err:
1676 scm_destroy(siocb->scm);
1677 siocb->scm = NULL;
1678 return sent ? : err;
1679}
1680
1681static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1682 struct msghdr *msg, size_t len)
1683{
1684 int err;
1685 struct sock *sk = sock->sk;
1686
1687 err = sock_error(sk);
1688 if (err)
1689 return err;
1690
1691 if (sk->sk_state != TCP_ESTABLISHED)
1692 return -ENOTCONN;
1693
1694 if (msg->msg_namelen)
1695 msg->msg_namelen = 0;
1696
1697 return unix_dgram_sendmsg(kiocb, sock, msg, len);
1698}
1699
1700static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
1701 struct msghdr *msg, size_t size,
1702 int flags)
1703{
1704 struct sock *sk = sock->sk;
1705
1706 if (sk->sk_state != TCP_ESTABLISHED)
1707 return -ENOTCONN;
1708
1709 return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
1710}
1711
1712static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1713{
1714 struct unix_sock *u = unix_sk(sk);
1715
1716 msg->msg_namelen = 0;
1717 if (u->addr) {
1718 msg->msg_namelen = u->addr->len;
1719 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1720 }
1721}
1722
1723static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1724 struct msghdr *msg, size_t size,
1725 int flags)
1726{
1727 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1728 struct scm_cookie tmp_scm;
1729 struct sock *sk = sock->sk;
1730 struct unix_sock *u = unix_sk(sk);
1731 int noblock = flags & MSG_DONTWAIT;
1732 struct sk_buff *skb;
1733 int err;
1734
1735 err = -EOPNOTSUPP;
1736 if (flags&MSG_OOB)
1737 goto out;
1738
1739 msg->msg_namelen = 0;
1740
1741 err = mutex_lock_interruptible(&u->readlock);
1742 if (err) {
1743 err = sock_intr_errno(sock_rcvtimeo(sk, noblock));
1744 goto out;
1745 }
1746
1747 skb = skb_recv_datagram(sk, flags, noblock, &err);
1748 if (!skb) {
1749 unix_state_lock(sk);
1750 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1751 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1752 (sk->sk_shutdown & RCV_SHUTDOWN))
1753 err = 0;
1754 unix_state_unlock(sk);
1755 goto out_unlock;
1756 }
1757
1758 wake_up_interruptible_sync_poll(&u->peer_wait,
1759 POLLOUT | POLLWRNORM | POLLWRBAND);
1760
1761 if (msg->msg_name)
1762 unix_copy_addr(msg, skb->sk);
1763
1764 if (size > skb->len)
1765 size = skb->len;
1766 else if (size < skb->len)
1767 msg->msg_flags |= MSG_TRUNC;
1768
1769 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1770 if (err)
1771 goto out_free;
1772
1773 if (sock_flag(sk, SOCK_RCVTSTAMP))
1774 __sock_recv_timestamp(msg, sk, skb);
1775
1776 if (!siocb->scm) {
1777 siocb->scm = &tmp_scm;
1778 memset(&tmp_scm, 0, sizeof(tmp_scm));
1779 }
1780 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1781 unix_set_secdata(siocb->scm, skb);
1782
1783 if (!(flags & MSG_PEEK)) {
1784 if (UNIXCB(skb).fp)
1785 unix_detach_fds(siocb->scm, skb);
1786 } else {
1787 /* It is questionable: on PEEK we could:
1788 - do not return fds - good, but too simple 8)
1789 - return fds, and do not return them on read (old strategy,
1790 apparently wrong)
1791 - clone fds (I chose it for now, it is the most universal
1792 solution)
1793
1794 POSIX 1003.1g does not actually define this clearly
1795 at all. POSIX 1003.1g doesn't define a lot of things
1796 clearly however!
1797
1798 */
1799 if (UNIXCB(skb).fp)
1800 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1801 }
1802 err = size;
1803
1804 scm_recv(sock, msg, siocb->scm, flags);
1805
1806out_free:
1807 skb_free_datagram(sk, skb);
1808out_unlock:
1809 mutex_unlock(&u->readlock);
1810out:
1811 return err;
1812}
1813
1814/*
1815 * Sleep until data has arrive. But check for races..
1816 */
1817
1818static long unix_stream_data_wait(struct sock *sk, long timeo)
1819{
1820 DEFINE_WAIT(wait);
1821
1822 unix_state_lock(sk);
1823
1824 for (;;) {
1825 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1826
1827 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1828 sk->sk_err ||
1829 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1830 signal_pending(current) ||
1831 !timeo)
1832 break;
1833
1834 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1835 unix_state_unlock(sk);
1836 timeo = schedule_timeout(timeo);
1837 unix_state_lock(sk);
1838 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1839 }
1840
1841 finish_wait(sk_sleep(sk), &wait);
1842 unix_state_unlock(sk);
1843 return timeo;
1844}
1845
1846
1847
1848static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1849 struct msghdr *msg, size_t size,
1850 int flags)
1851{
1852 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1853 struct scm_cookie tmp_scm;
1854 struct sock *sk = sock->sk;
1855 struct unix_sock *u = unix_sk(sk);
1856 struct sockaddr_un *sunaddr = msg->msg_name;
1857 int copied = 0;
1858 int check_creds = 0;
1859 int target;
1860 int err = 0;
1861 long timeo;
1862
1863 err = -EINVAL;
1864 if (sk->sk_state != TCP_ESTABLISHED)
1865 goto out;
1866
1867 err = -EOPNOTSUPP;
1868 if (flags&MSG_OOB)
1869 goto out;
1870
1871 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1872 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1873
1874 msg->msg_namelen = 0;
1875
1876 /* Lock the socket to prevent queue disordering
1877 * while sleeps in memcpy_tomsg
1878 */
1879
1880 if (!siocb->scm) {
1881 siocb->scm = &tmp_scm;
1882 memset(&tmp_scm, 0, sizeof(tmp_scm));
1883 }
1884
1885 err = mutex_lock_interruptible(&u->readlock);
1886 if (err) {
1887 err = sock_intr_errno(timeo);
1888 goto out;
1889 }
1890
1891 do {
1892 int chunk;
1893 struct sk_buff *skb;
1894
1895 unix_state_lock(sk);
1896 skb = skb_dequeue(&sk->sk_receive_queue);
1897 if (skb == NULL) {
1898 unix_sk(sk)->recursion_level = 0;
1899 if (copied >= target)
1900 goto unlock;
1901
1902 /*
1903 * POSIX 1003.1g mandates this order.
1904 */
1905
1906 err = sock_error(sk);
1907 if (err)
1908 goto unlock;
1909 if (sk->sk_shutdown & RCV_SHUTDOWN)
1910 goto unlock;
1911
1912 unix_state_unlock(sk);
1913 err = -EAGAIN;
1914 if (!timeo)
1915 break;
1916 mutex_unlock(&u->readlock);
1917
1918 timeo = unix_stream_data_wait(sk, timeo);
1919
1920 if (signal_pending(current)
1921 || mutex_lock_interruptible(&u->readlock)) {
1922 err = sock_intr_errno(timeo);
1923 goto out;
1924 }
1925
1926 continue;
1927 unlock:
1928 unix_state_unlock(sk);
1929 break;
1930 }
1931 unix_state_unlock(sk);
1932
1933 if (check_creds) {
1934 /* Never glue messages from different writers */
1935 if ((UNIXCB(skb).pid != siocb->scm->pid) ||
1936 (UNIXCB(skb).cred != siocb->scm->cred)) {
1937 skb_queue_head(&sk->sk_receive_queue, skb);
1938 break;
1939 }
1940 } else {
1941 /* Copy credentials */
1942 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1943 check_creds = 1;
1944 }
1945
1946 /* Copy address just once */
1947 if (sunaddr) {
1948 unix_copy_addr(msg, skb->sk);
1949 sunaddr = NULL;
1950 }
1951
1952 chunk = min_t(unsigned int, skb->len, size);
1953 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
1954 skb_queue_head(&sk->sk_receive_queue, skb);
1955 if (copied == 0)
1956 copied = -EFAULT;
1957 break;
1958 }
1959 copied += chunk;
1960 size -= chunk;
1961
1962 /* Mark read part of skb as used */
1963 if (!(flags & MSG_PEEK)) {
1964 skb_pull(skb, chunk);
1965
1966 if (UNIXCB(skb).fp)
1967 unix_detach_fds(siocb->scm, skb);
1968
1969 /* put the skb back if we didn't use it up.. */
1970 if (skb->len) {
1971 skb_queue_head(&sk->sk_receive_queue, skb);
1972 break;
1973 }
1974
1975 consume_skb(skb);
1976
1977 if (siocb->scm->fp)
1978 break;
1979 } else {
1980 /* It is questionable, see note in unix_dgram_recvmsg.
1981 */
1982 if (UNIXCB(skb).fp)
1983 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1984
1985 /* put message back and return */
1986 skb_queue_head(&sk->sk_receive_queue, skb);
1987 break;
1988 }
1989 } while (size);
1990
1991 mutex_unlock(&u->readlock);
1992 scm_recv(sock, msg, siocb->scm, flags);
1993out:
1994 return copied ? : err;
1995}
1996
1997static int unix_shutdown(struct socket *sock, int mode)
1998{
1999 struct sock *sk = sock->sk;
2000 struct sock *other;
2001
2002 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
2003
2004 if (!mode)
2005 return 0;
2006
2007 unix_state_lock(sk);
2008 sk->sk_shutdown |= mode;
2009 other = unix_peer(sk);
2010 if (other)
2011 sock_hold(other);
2012 unix_state_unlock(sk);
2013 sk->sk_state_change(sk);
2014
2015 if (other &&
2016 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2017
2018 int peer_mode = 0;
2019
2020 if (mode&RCV_SHUTDOWN)
2021 peer_mode |= SEND_SHUTDOWN;
2022 if (mode&SEND_SHUTDOWN)
2023 peer_mode |= RCV_SHUTDOWN;
2024 unix_state_lock(other);
2025 other->sk_shutdown |= peer_mode;
2026 unix_state_unlock(other);
2027 other->sk_state_change(other);
2028 if (peer_mode == SHUTDOWN_MASK)
2029 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2030 else if (peer_mode & RCV_SHUTDOWN)
2031 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2032 }
2033 if (other)
2034 sock_put(other);
2035
2036 return 0;
2037}
2038
2039static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2040{
2041 struct sock *sk = sock->sk;
2042 long amount = 0;
2043 int err;
2044
2045 switch (cmd) {
2046 case SIOCOUTQ:
2047 amount = sk_wmem_alloc_get(sk);
2048 err = put_user(amount, (int __user *)arg);
2049 break;
2050 case SIOCINQ:
2051 {
2052 struct sk_buff *skb;
2053
2054 if (sk->sk_state == TCP_LISTEN) {
2055 err = -EINVAL;
2056 break;
2057 }
2058
2059 spin_lock(&sk->sk_receive_queue.lock);
2060 if (sk->sk_type == SOCK_STREAM ||
2061 sk->sk_type == SOCK_SEQPACKET) {
2062 skb_queue_walk(&sk->sk_receive_queue, skb)
2063 amount += skb->len;
2064 } else {
2065 skb = skb_peek(&sk->sk_receive_queue);
2066 if (skb)
2067 amount = skb->len;
2068 }
2069 spin_unlock(&sk->sk_receive_queue.lock);
2070 err = put_user(amount, (int __user *)arg);
2071 break;
2072 }
2073
2074 default:
2075 err = -ENOIOCTLCMD;
2076 break;
2077 }
2078 return err;
2079}
2080
2081static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2082{
2083 struct sock *sk = sock->sk;
2084 unsigned int mask;
2085
2086 sock_poll_wait(file, sk_sleep(sk), wait);
2087 mask = 0;
2088
2089 /* exceptional events? */
2090 if (sk->sk_err)
2091 mask |= POLLERR;
2092 if (sk->sk_shutdown == SHUTDOWN_MASK)
2093 mask |= POLLHUP;
2094 if (sk->sk_shutdown & RCV_SHUTDOWN)
2095 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2096
2097 /* readable? */
2098 if (!skb_queue_empty(&sk->sk_receive_queue))
2099 mask |= POLLIN | POLLRDNORM;
2100
2101 /* Connection-based need to check for termination and startup */
2102 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2103 sk->sk_state == TCP_CLOSE)
2104 mask |= POLLHUP;
2105
2106 /*
2107 * we set writable also when the other side has shut down the
2108 * connection. This prevents stuck sockets.
2109 */
2110 if (unix_writable(sk))
2111 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2112
2113 return mask;
2114}
2115
2116static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2117 poll_table *wait)
2118{
2119 struct sock *sk = sock->sk, *other;
2120 unsigned int mask, writable;
2121
2122 sock_poll_wait(file, sk_sleep(sk), wait);
2123 mask = 0;
2124
2125 /* exceptional events? */
2126 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2127 mask |= POLLERR;
2128 if (sk->sk_shutdown & RCV_SHUTDOWN)
2129 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2130 if (sk->sk_shutdown == SHUTDOWN_MASK)
2131 mask |= POLLHUP;
2132
2133 /* readable? */
2134 if (!skb_queue_empty(&sk->sk_receive_queue))
2135 mask |= POLLIN | POLLRDNORM;
2136
2137 /* Connection-based need to check for termination and startup */
2138 if (sk->sk_type == SOCK_SEQPACKET) {
2139 if (sk->sk_state == TCP_CLOSE)
2140 mask |= POLLHUP;
2141 /* connection hasn't started yet? */
2142 if (sk->sk_state == TCP_SYN_SENT)
2143 return mask;
2144 }
2145
2146 /* No write status requested, avoid expensive OUT tests. */
2147 if (wait && !(wait->key & (POLLWRBAND | POLLWRNORM | POLLOUT)))
2148 return mask;
2149
2150 writable = unix_writable(sk);
2151 other = unix_peer_get(sk);
2152 if (other) {
2153 if (unix_peer(other) != sk) {
2154 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
2155 if (unix_recvq_full(other))
2156 writable = 0;
2157 }
2158 sock_put(other);
2159 }
2160
2161 if (writable)
2162 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2163 else
2164 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2165
2166 return mask;
2167}
2168
2169#ifdef CONFIG_PROC_FS
2170static struct sock *first_unix_socket(int *i)
2171{
2172 for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2173 if (!hlist_empty(&unix_socket_table[*i]))
2174 return __sk_head(&unix_socket_table[*i]);
2175 }
2176 return NULL;
2177}
2178
2179static struct sock *next_unix_socket(int *i, struct sock *s)
2180{
2181 struct sock *next = sk_next(s);
2182 /* More in this chain? */
2183 if (next)
2184 return next;
2185 /* Look for next non-empty chain. */
2186 for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2187 if (!hlist_empty(&unix_socket_table[*i]))
2188 return __sk_head(&unix_socket_table[*i]);
2189 }
2190 return NULL;
2191}
2192
2193struct unix_iter_state {
2194 struct seq_net_private p;
2195 int i;
2196};
2197
2198static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2199{
2200 struct unix_iter_state *iter = seq->private;
2201 loff_t off = 0;
2202 struct sock *s;
2203
2204 for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2205 if (sock_net(s) != seq_file_net(seq))
2206 continue;
2207 if (off == pos)
2208 return s;
2209 ++off;
2210 }
2211 return NULL;
2212}
2213
2214static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2215 __acquires(unix_table_lock)
2216{
2217 spin_lock(&unix_table_lock);
2218 return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2219}
2220
2221static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2222{
2223 struct unix_iter_state *iter = seq->private;
2224 struct sock *sk = v;
2225 ++*pos;
2226
2227 if (v == SEQ_START_TOKEN)
2228 sk = first_unix_socket(&iter->i);
2229 else
2230 sk = next_unix_socket(&iter->i, sk);
2231 while (sk && (sock_net(sk) != seq_file_net(seq)))
2232 sk = next_unix_socket(&iter->i, sk);
2233 return sk;
2234}
2235
2236static void unix_seq_stop(struct seq_file *seq, void *v)
2237 __releases(unix_table_lock)
2238{
2239 spin_unlock(&unix_table_lock);
2240}
2241
2242static int unix_seq_show(struct seq_file *seq, void *v)
2243{
2244
2245 if (v == SEQ_START_TOKEN)
2246 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2247 "Inode Path\n");
2248 else {
2249 struct sock *s = v;
2250 struct unix_sock *u = unix_sk(s);
2251 unix_state_lock(s);
2252
2253 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2254 s,
2255 atomic_read(&s->sk_refcnt),
2256 0,
2257 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2258 s->sk_type,
2259 s->sk_socket ?
2260 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2261 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2262 sock_i_ino(s));
2263
2264 if (u->addr) {
2265 int i, len;
2266 seq_putc(seq, ' ');
2267
2268 i = 0;
2269 len = u->addr->len - sizeof(short);
2270 if (!UNIX_ABSTRACT(s))
2271 len--;
2272 else {
2273 seq_putc(seq, '@');
2274 i++;
2275 }
2276 for ( ; i < len; i++)
2277 seq_putc(seq, u->addr->name->sun_path[i]);
2278 }
2279 unix_state_unlock(s);
2280 seq_putc(seq, '\n');
2281 }
2282
2283 return 0;
2284}
2285
2286static const struct seq_operations unix_seq_ops = {
2287 .start = unix_seq_start,
2288 .next = unix_seq_next,
2289 .stop = unix_seq_stop,
2290 .show = unix_seq_show,
2291};
2292
2293static int unix_seq_open(struct inode *inode, struct file *file)
2294{
2295 return seq_open_net(inode, file, &unix_seq_ops,
2296 sizeof(struct unix_iter_state));
2297}
2298
2299static const struct file_operations unix_seq_fops = {
2300 .owner = THIS_MODULE,
2301 .open = unix_seq_open,
2302 .read = seq_read,
2303 .llseek = seq_lseek,
2304 .release = seq_release_net,
2305};
2306
2307#endif
2308
2309static const struct net_proto_family unix_family_ops = {
2310 .family = PF_UNIX,
2311 .create = unix_create,
2312 .owner = THIS_MODULE,
2313};
2314
2315
2316static int __net_init unix_net_init(struct net *net)
2317{
2318 int error = -ENOMEM;
2319
2320 net->unx.sysctl_max_dgram_qlen = 10;
2321 if (unix_sysctl_register(net))
2322 goto out;
2323
2324#ifdef CONFIG_PROC_FS
2325 if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2326 unix_sysctl_unregister(net);
2327 goto out;
2328 }
2329#endif
2330 error = 0;
2331out:
2332 return error;
2333}
2334
2335static void __net_exit unix_net_exit(struct net *net)
2336{
2337 unix_sysctl_unregister(net);
2338 proc_net_remove(net, "unix");
2339}
2340
2341static struct pernet_operations unix_net_ops = {
2342 .init = unix_net_init,
2343 .exit = unix_net_exit,
2344};
2345
2346static int __init af_unix_init(void)
2347{
2348 int rc = -1;
2349 struct sk_buff *dummy_skb;
2350
2351 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2352
2353 rc = proto_register(&unix_proto, 1);
2354 if (rc != 0) {
2355 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2356 __func__);
2357 goto out;
2358 }
2359
2360 sock_register(&unix_family_ops);
2361 register_pernet_subsys(&unix_net_ops);
2362out:
2363 return rc;
2364}
2365
2366static void __exit af_unix_exit(void)
2367{
2368 sock_unregister(PF_UNIX);
2369 proto_unregister(&unix_proto);
2370 unregister_pernet_subsys(&unix_net_ops);
2371}
2372
2373/* Earlier than device_initcall() so that other drivers invoking
2374 request_module() don't end up in a loop when modprobe tries
2375 to use a UNIX socket. But later than subsys_initcall() because
2376 we depend on stuff initialised there */
2377fs_initcall(af_unix_init);
2378module_exit(af_unix_exit);
2379
2380MODULE_LICENSE("GPL");
2381MODULE_ALIAS_NETPROTO(PF_UNIX);