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