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