Loading...
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/filter.h>
93#include <linux/termios.h>
94#include <linux/sockios.h>
95#include <linux/net.h>
96#include <linux/in.h>
97#include <linux/fs.h>
98#include <linux/slab.h>
99#include <linux/uaccess.h>
100#include <linux/skbuff.h>
101#include <linux/netdevice.h>
102#include <net/net_namespace.h>
103#include <net/sock.h>
104#include <net/tcp_states.h>
105#include <net/af_unix.h>
106#include <linux/proc_fs.h>
107#include <linux/seq_file.h>
108#include <net/scm.h>
109#include <linux/init.h>
110#include <linux/poll.h>
111#include <linux/rtnetlink.h>
112#include <linux/mount.h>
113#include <net/checksum.h>
114#include <linux/security.h>
115#include <linux/freezer.h>
116#include <linux/file.h>
117#include <linux/btf_ids.h>
118
119#include "scm.h"
120
121static atomic_long_t unix_nr_socks;
122static struct hlist_head bsd_socket_buckets[UNIX_HASH_SIZE / 2];
123static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2];
124
125/* SMP locking strategy:
126 * hash table is protected with spinlock.
127 * each socket state is protected by separate spinlock.
128 */
129
130static unsigned int unix_unbound_hash(struct sock *sk)
131{
132 unsigned long hash = (unsigned long)sk;
133
134 hash ^= hash >> 16;
135 hash ^= hash >> 8;
136 hash ^= sk->sk_type;
137
138 return hash & UNIX_HASH_MOD;
139}
140
141static unsigned int unix_bsd_hash(struct inode *i)
142{
143 return i->i_ino & UNIX_HASH_MOD;
144}
145
146static unsigned int unix_abstract_hash(struct sockaddr_un *sunaddr,
147 int addr_len, int type)
148{
149 __wsum csum = csum_partial(sunaddr, addr_len, 0);
150 unsigned int hash;
151
152 hash = (__force unsigned int)csum_fold(csum);
153 hash ^= hash >> 8;
154 hash ^= type;
155
156 return UNIX_HASH_MOD + 1 + (hash & UNIX_HASH_MOD);
157}
158
159static void unix_table_double_lock(struct net *net,
160 unsigned int hash1, unsigned int hash2)
161{
162 if (hash1 == hash2) {
163 spin_lock(&net->unx.table.locks[hash1]);
164 return;
165 }
166
167 if (hash1 > hash2)
168 swap(hash1, hash2);
169
170 spin_lock(&net->unx.table.locks[hash1]);
171 spin_lock_nested(&net->unx.table.locks[hash2], SINGLE_DEPTH_NESTING);
172}
173
174static void unix_table_double_unlock(struct net *net,
175 unsigned int hash1, unsigned int hash2)
176{
177 if (hash1 == hash2) {
178 spin_unlock(&net->unx.table.locks[hash1]);
179 return;
180 }
181
182 spin_unlock(&net->unx.table.locks[hash1]);
183 spin_unlock(&net->unx.table.locks[hash2]);
184}
185
186#ifdef CONFIG_SECURITY_NETWORK
187static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
188{
189 UNIXCB(skb).secid = scm->secid;
190}
191
192static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
193{
194 scm->secid = UNIXCB(skb).secid;
195}
196
197static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
198{
199 return (scm->secid == UNIXCB(skb).secid);
200}
201#else
202static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
203{ }
204
205static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
206{ }
207
208static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
209{
210 return true;
211}
212#endif /* CONFIG_SECURITY_NETWORK */
213
214#define unix_peer(sk) (unix_sk(sk)->peer)
215
216static inline int unix_our_peer(struct sock *sk, struct sock *osk)
217{
218 return unix_peer(osk) == sk;
219}
220
221static inline int unix_may_send(struct sock *sk, struct sock *osk)
222{
223 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
224}
225
226static inline int unix_recvq_full(const struct sock *sk)
227{
228 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
229}
230
231static inline int unix_recvq_full_lockless(const struct sock *sk)
232{
233 return skb_queue_len_lockless(&sk->sk_receive_queue) >
234 READ_ONCE(sk->sk_max_ack_backlog);
235}
236
237struct sock *unix_peer_get(struct sock *s)
238{
239 struct sock *peer;
240
241 unix_state_lock(s);
242 peer = unix_peer(s);
243 if (peer)
244 sock_hold(peer);
245 unix_state_unlock(s);
246 return peer;
247}
248EXPORT_SYMBOL_GPL(unix_peer_get);
249
250static struct unix_address *unix_create_addr(struct sockaddr_un *sunaddr,
251 int addr_len)
252{
253 struct unix_address *addr;
254
255 addr = kmalloc(sizeof(*addr) + addr_len, GFP_KERNEL);
256 if (!addr)
257 return NULL;
258
259 refcount_set(&addr->refcnt, 1);
260 addr->len = addr_len;
261 memcpy(addr->name, sunaddr, addr_len);
262
263 return addr;
264}
265
266static inline void unix_release_addr(struct unix_address *addr)
267{
268 if (refcount_dec_and_test(&addr->refcnt))
269 kfree(addr);
270}
271
272/*
273 * Check unix socket name:
274 * - should be not zero length.
275 * - if started by not zero, should be NULL terminated (FS object)
276 * - if started by zero, it is abstract name.
277 */
278
279static int unix_validate_addr(struct sockaddr_un *sunaddr, int addr_len)
280{
281 if (addr_len <= offsetof(struct sockaddr_un, sun_path) ||
282 addr_len > sizeof(*sunaddr))
283 return -EINVAL;
284
285 if (sunaddr->sun_family != AF_UNIX)
286 return -EINVAL;
287
288 return 0;
289}
290
291static void unix_mkname_bsd(struct sockaddr_un *sunaddr, int addr_len)
292{
293 /* This may look like an off by one error but it is a bit more
294 * subtle. 108 is the longest valid AF_UNIX path for a binding.
295 * sun_path[108] doesn't as such exist. However in kernel space
296 * we are guaranteed that it is a valid memory location in our
297 * kernel address buffer because syscall functions always pass
298 * a pointer of struct sockaddr_storage which has a bigger buffer
299 * than 108.
300 */
301 ((char *)sunaddr)[addr_len] = 0;
302}
303
304static void __unix_remove_socket(struct sock *sk)
305{
306 sk_del_node_init(sk);
307}
308
309static void __unix_insert_socket(struct net *net, struct sock *sk)
310{
311 DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk));
312 sk_add_node(sk, &net->unx.table.buckets[sk->sk_hash]);
313}
314
315static void __unix_set_addr_hash(struct net *net, struct sock *sk,
316 struct unix_address *addr, unsigned int hash)
317{
318 __unix_remove_socket(sk);
319 smp_store_release(&unix_sk(sk)->addr, addr);
320
321 sk->sk_hash = hash;
322 __unix_insert_socket(net, sk);
323}
324
325static void unix_remove_socket(struct net *net, struct sock *sk)
326{
327 spin_lock(&net->unx.table.locks[sk->sk_hash]);
328 __unix_remove_socket(sk);
329 spin_unlock(&net->unx.table.locks[sk->sk_hash]);
330}
331
332static void unix_insert_unbound_socket(struct net *net, struct sock *sk)
333{
334 spin_lock(&net->unx.table.locks[sk->sk_hash]);
335 __unix_insert_socket(net, sk);
336 spin_unlock(&net->unx.table.locks[sk->sk_hash]);
337}
338
339static void unix_insert_bsd_socket(struct sock *sk)
340{
341 spin_lock(&bsd_socket_locks[sk->sk_hash]);
342 sk_add_bind_node(sk, &bsd_socket_buckets[sk->sk_hash]);
343 spin_unlock(&bsd_socket_locks[sk->sk_hash]);
344}
345
346static void unix_remove_bsd_socket(struct sock *sk)
347{
348 if (!hlist_unhashed(&sk->sk_bind_node)) {
349 spin_lock(&bsd_socket_locks[sk->sk_hash]);
350 __sk_del_bind_node(sk);
351 spin_unlock(&bsd_socket_locks[sk->sk_hash]);
352
353 sk_node_init(&sk->sk_bind_node);
354 }
355}
356
357static struct sock *__unix_find_socket_byname(struct net *net,
358 struct sockaddr_un *sunname,
359 int len, unsigned int hash)
360{
361 struct sock *s;
362
363 sk_for_each(s, &net->unx.table.buckets[hash]) {
364 struct unix_sock *u = unix_sk(s);
365
366 if (u->addr->len == len &&
367 !memcmp(u->addr->name, sunname, len))
368 return s;
369 }
370 return NULL;
371}
372
373static inline struct sock *unix_find_socket_byname(struct net *net,
374 struct sockaddr_un *sunname,
375 int len, unsigned int hash)
376{
377 struct sock *s;
378
379 spin_lock(&net->unx.table.locks[hash]);
380 s = __unix_find_socket_byname(net, sunname, len, hash);
381 if (s)
382 sock_hold(s);
383 spin_unlock(&net->unx.table.locks[hash]);
384 return s;
385}
386
387static struct sock *unix_find_socket_byinode(struct inode *i)
388{
389 unsigned int hash = unix_bsd_hash(i);
390 struct sock *s;
391
392 spin_lock(&bsd_socket_locks[hash]);
393 sk_for_each_bound(s, &bsd_socket_buckets[hash]) {
394 struct dentry *dentry = unix_sk(s)->path.dentry;
395
396 if (dentry && d_backing_inode(dentry) == i) {
397 sock_hold(s);
398 spin_unlock(&bsd_socket_locks[hash]);
399 return s;
400 }
401 }
402 spin_unlock(&bsd_socket_locks[hash]);
403 return NULL;
404}
405
406/* Support code for asymmetrically connected dgram sockets
407 *
408 * If a datagram socket is connected to a socket not itself connected
409 * to the first socket (eg, /dev/log), clients may only enqueue more
410 * messages if the present receive queue of the server socket is not
411 * "too large". This means there's a second writeability condition
412 * poll and sendmsg need to test. The dgram recv code will do a wake
413 * up on the peer_wait wait queue of a socket upon reception of a
414 * datagram which needs to be propagated to sleeping would-be writers
415 * since these might not have sent anything so far. This can't be
416 * accomplished via poll_wait because the lifetime of the server
417 * socket might be less than that of its clients if these break their
418 * association with it or if the server socket is closed while clients
419 * are still connected to it and there's no way to inform "a polling
420 * implementation" that it should let go of a certain wait queue
421 *
422 * In order to propagate a wake up, a wait_queue_entry_t of the client
423 * socket is enqueued on the peer_wait queue of the server socket
424 * whose wake function does a wake_up on the ordinary client socket
425 * wait queue. This connection is established whenever a write (or
426 * poll for write) hit the flow control condition and broken when the
427 * association to the server socket is dissolved or after a wake up
428 * was relayed.
429 */
430
431static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
432 void *key)
433{
434 struct unix_sock *u;
435 wait_queue_head_t *u_sleep;
436
437 u = container_of(q, struct unix_sock, peer_wake);
438
439 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
440 q);
441 u->peer_wake.private = NULL;
442
443 /* relaying can only happen while the wq still exists */
444 u_sleep = sk_sleep(&u->sk);
445 if (u_sleep)
446 wake_up_interruptible_poll(u_sleep, key_to_poll(key));
447
448 return 0;
449}
450
451static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
452{
453 struct unix_sock *u, *u_other;
454 int rc;
455
456 u = unix_sk(sk);
457 u_other = unix_sk(other);
458 rc = 0;
459 spin_lock(&u_other->peer_wait.lock);
460
461 if (!u->peer_wake.private) {
462 u->peer_wake.private = other;
463 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
464
465 rc = 1;
466 }
467
468 spin_unlock(&u_other->peer_wait.lock);
469 return rc;
470}
471
472static void unix_dgram_peer_wake_disconnect(struct sock *sk,
473 struct sock *other)
474{
475 struct unix_sock *u, *u_other;
476
477 u = unix_sk(sk);
478 u_other = unix_sk(other);
479 spin_lock(&u_other->peer_wait.lock);
480
481 if (u->peer_wake.private == other) {
482 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
483 u->peer_wake.private = NULL;
484 }
485
486 spin_unlock(&u_other->peer_wait.lock);
487}
488
489static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
490 struct sock *other)
491{
492 unix_dgram_peer_wake_disconnect(sk, other);
493 wake_up_interruptible_poll(sk_sleep(sk),
494 EPOLLOUT |
495 EPOLLWRNORM |
496 EPOLLWRBAND);
497}
498
499/* preconditions:
500 * - unix_peer(sk) == other
501 * - association is stable
502 */
503static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
504{
505 int connected;
506
507 connected = unix_dgram_peer_wake_connect(sk, other);
508
509 /* If other is SOCK_DEAD, we want to make sure we signal
510 * POLLOUT, such that a subsequent write() can get a
511 * -ECONNREFUSED. Otherwise, if we haven't queued any skbs
512 * to other and its full, we will hang waiting for POLLOUT.
513 */
514 if (unix_recvq_full_lockless(other) && !sock_flag(other, SOCK_DEAD))
515 return 1;
516
517 if (connected)
518 unix_dgram_peer_wake_disconnect(sk, other);
519
520 return 0;
521}
522
523static int unix_writable(const struct sock *sk)
524{
525 return sk->sk_state != TCP_LISTEN &&
526 (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
527}
528
529static void unix_write_space(struct sock *sk)
530{
531 struct socket_wq *wq;
532
533 rcu_read_lock();
534 if (unix_writable(sk)) {
535 wq = rcu_dereference(sk->sk_wq);
536 if (skwq_has_sleeper(wq))
537 wake_up_interruptible_sync_poll(&wq->wait,
538 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
539 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
540 }
541 rcu_read_unlock();
542}
543
544/* When dgram socket disconnects (or changes its peer), we clear its receive
545 * queue of packets arrived from previous peer. First, it allows to do
546 * flow control based only on wmem_alloc; second, sk connected to peer
547 * may receive messages only from that peer. */
548static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
549{
550 if (!skb_queue_empty(&sk->sk_receive_queue)) {
551 skb_queue_purge(&sk->sk_receive_queue);
552 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
553
554 /* If one link of bidirectional dgram pipe is disconnected,
555 * we signal error. Messages are lost. Do not make this,
556 * when peer was not connected to us.
557 */
558 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
559 other->sk_err = ECONNRESET;
560 sk_error_report(other);
561 }
562 }
563 other->sk_state = TCP_CLOSE;
564}
565
566static void unix_sock_destructor(struct sock *sk)
567{
568 struct unix_sock *u = unix_sk(sk);
569
570 skb_queue_purge(&sk->sk_receive_queue);
571
572 DEBUG_NET_WARN_ON_ONCE(refcount_read(&sk->sk_wmem_alloc));
573 DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk));
574 DEBUG_NET_WARN_ON_ONCE(sk->sk_socket);
575 if (!sock_flag(sk, SOCK_DEAD)) {
576 pr_info("Attempt to release alive unix socket: %p\n", sk);
577 return;
578 }
579
580 if (u->addr)
581 unix_release_addr(u->addr);
582
583 atomic_long_dec(&unix_nr_socks);
584 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
585#ifdef UNIX_REFCNT_DEBUG
586 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
587 atomic_long_read(&unix_nr_socks));
588#endif
589}
590
591static void unix_release_sock(struct sock *sk, int embrion)
592{
593 struct unix_sock *u = unix_sk(sk);
594 struct sock *skpair;
595 struct sk_buff *skb;
596 struct path path;
597 int state;
598
599 unix_remove_socket(sock_net(sk), sk);
600 unix_remove_bsd_socket(sk);
601
602 /* Clear state */
603 unix_state_lock(sk);
604 sock_orphan(sk);
605 sk->sk_shutdown = SHUTDOWN_MASK;
606 path = u->path;
607 u->path.dentry = NULL;
608 u->path.mnt = NULL;
609 state = sk->sk_state;
610 sk->sk_state = TCP_CLOSE;
611
612 skpair = unix_peer(sk);
613 unix_peer(sk) = NULL;
614
615 unix_state_unlock(sk);
616
617#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
618 if (u->oob_skb) {
619 kfree_skb(u->oob_skb);
620 u->oob_skb = NULL;
621 }
622#endif
623
624 wake_up_interruptible_all(&u->peer_wait);
625
626 if (skpair != NULL) {
627 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
628 unix_state_lock(skpair);
629 /* No more writes */
630 skpair->sk_shutdown = SHUTDOWN_MASK;
631 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
632 skpair->sk_err = ECONNRESET;
633 unix_state_unlock(skpair);
634 skpair->sk_state_change(skpair);
635 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
636 }
637
638 unix_dgram_peer_wake_disconnect(sk, skpair);
639 sock_put(skpair); /* It may now die */
640 }
641
642 /* Try to flush out this socket. Throw out buffers at least */
643
644 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
645 if (state == TCP_LISTEN)
646 unix_release_sock(skb->sk, 1);
647 /* passed fds are erased in the kfree_skb hook */
648 UNIXCB(skb).consumed = skb->len;
649 kfree_skb(skb);
650 }
651
652 if (path.dentry)
653 path_put(&path);
654
655 sock_put(sk);
656
657 /* ---- Socket is dead now and most probably destroyed ---- */
658
659 /*
660 * Fixme: BSD difference: In BSD all sockets connected to us get
661 * ECONNRESET and we die on the spot. In Linux we behave
662 * like files and pipes do and wait for the last
663 * dereference.
664 *
665 * Can't we simply set sock->err?
666 *
667 * What the above comment does talk about? --ANK(980817)
668 */
669
670 if (unix_tot_inflight)
671 unix_gc(); /* Garbage collect fds */
672}
673
674static void init_peercred(struct sock *sk)
675{
676 const struct cred *old_cred;
677 struct pid *old_pid;
678
679 spin_lock(&sk->sk_peer_lock);
680 old_pid = sk->sk_peer_pid;
681 old_cred = sk->sk_peer_cred;
682 sk->sk_peer_pid = get_pid(task_tgid(current));
683 sk->sk_peer_cred = get_current_cred();
684 spin_unlock(&sk->sk_peer_lock);
685
686 put_pid(old_pid);
687 put_cred(old_cred);
688}
689
690static void copy_peercred(struct sock *sk, struct sock *peersk)
691{
692 const struct cred *old_cred;
693 struct pid *old_pid;
694
695 if (sk < peersk) {
696 spin_lock(&sk->sk_peer_lock);
697 spin_lock_nested(&peersk->sk_peer_lock, SINGLE_DEPTH_NESTING);
698 } else {
699 spin_lock(&peersk->sk_peer_lock);
700 spin_lock_nested(&sk->sk_peer_lock, SINGLE_DEPTH_NESTING);
701 }
702 old_pid = sk->sk_peer_pid;
703 old_cred = sk->sk_peer_cred;
704 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
705 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
706
707 spin_unlock(&sk->sk_peer_lock);
708 spin_unlock(&peersk->sk_peer_lock);
709
710 put_pid(old_pid);
711 put_cred(old_cred);
712}
713
714static int unix_listen(struct socket *sock, int backlog)
715{
716 int err;
717 struct sock *sk = sock->sk;
718 struct unix_sock *u = unix_sk(sk);
719
720 err = -EOPNOTSUPP;
721 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
722 goto out; /* Only stream/seqpacket sockets accept */
723 err = -EINVAL;
724 if (!u->addr)
725 goto out; /* No listens on an unbound socket */
726 unix_state_lock(sk);
727 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
728 goto out_unlock;
729 if (backlog > sk->sk_max_ack_backlog)
730 wake_up_interruptible_all(&u->peer_wait);
731 sk->sk_max_ack_backlog = backlog;
732 sk->sk_state = TCP_LISTEN;
733 /* set credentials so connect can copy them */
734 init_peercred(sk);
735 err = 0;
736
737out_unlock:
738 unix_state_unlock(sk);
739out:
740 return err;
741}
742
743static int unix_release(struct socket *);
744static int unix_bind(struct socket *, struct sockaddr *, int);
745static int unix_stream_connect(struct socket *, struct sockaddr *,
746 int addr_len, int flags);
747static int unix_socketpair(struct socket *, struct socket *);
748static int unix_accept(struct socket *, struct socket *, int, bool);
749static int unix_getname(struct socket *, struct sockaddr *, int);
750static __poll_t unix_poll(struct file *, struct socket *, poll_table *);
751static __poll_t unix_dgram_poll(struct file *, struct socket *,
752 poll_table *);
753static int unix_ioctl(struct socket *, unsigned int, unsigned long);
754#ifdef CONFIG_COMPAT
755static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
756#endif
757static int unix_shutdown(struct socket *, int);
758static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
759static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
760static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
761 size_t size, int flags);
762static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
763 struct pipe_inode_info *, size_t size,
764 unsigned int flags);
765static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
766static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
767static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
768static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
769static int unix_dgram_connect(struct socket *, struct sockaddr *,
770 int, int);
771static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
772static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
773 int);
774
775static int unix_set_peek_off(struct sock *sk, int val)
776{
777 struct unix_sock *u = unix_sk(sk);
778
779 if (mutex_lock_interruptible(&u->iolock))
780 return -EINTR;
781
782 sk->sk_peek_off = val;
783 mutex_unlock(&u->iolock);
784
785 return 0;
786}
787
788#ifdef CONFIG_PROC_FS
789static int unix_count_nr_fds(struct sock *sk)
790{
791 struct sk_buff *skb;
792 struct unix_sock *u;
793 int nr_fds = 0;
794
795 spin_lock(&sk->sk_receive_queue.lock);
796 skb = skb_peek(&sk->sk_receive_queue);
797 while (skb) {
798 u = unix_sk(skb->sk);
799 nr_fds += atomic_read(&u->scm_stat.nr_fds);
800 skb = skb_peek_next(skb, &sk->sk_receive_queue);
801 }
802 spin_unlock(&sk->sk_receive_queue.lock);
803
804 return nr_fds;
805}
806
807static void unix_show_fdinfo(struct seq_file *m, struct socket *sock)
808{
809 struct sock *sk = sock->sk;
810 struct unix_sock *u;
811 int nr_fds;
812
813 if (sk) {
814 u = unix_sk(sk);
815 if (sock->type == SOCK_DGRAM) {
816 nr_fds = atomic_read(&u->scm_stat.nr_fds);
817 goto out_print;
818 }
819
820 unix_state_lock(sk);
821 if (sk->sk_state != TCP_LISTEN)
822 nr_fds = atomic_read(&u->scm_stat.nr_fds);
823 else
824 nr_fds = unix_count_nr_fds(sk);
825 unix_state_unlock(sk);
826out_print:
827 seq_printf(m, "scm_fds: %u\n", nr_fds);
828 }
829}
830#else
831#define unix_show_fdinfo NULL
832#endif
833
834static const struct proto_ops unix_stream_ops = {
835 .family = PF_UNIX,
836 .owner = THIS_MODULE,
837 .release = unix_release,
838 .bind = unix_bind,
839 .connect = unix_stream_connect,
840 .socketpair = unix_socketpair,
841 .accept = unix_accept,
842 .getname = unix_getname,
843 .poll = unix_poll,
844 .ioctl = unix_ioctl,
845#ifdef CONFIG_COMPAT
846 .compat_ioctl = unix_compat_ioctl,
847#endif
848 .listen = unix_listen,
849 .shutdown = unix_shutdown,
850 .sendmsg = unix_stream_sendmsg,
851 .recvmsg = unix_stream_recvmsg,
852 .read_skb = unix_stream_read_skb,
853 .mmap = sock_no_mmap,
854 .sendpage = unix_stream_sendpage,
855 .splice_read = unix_stream_splice_read,
856 .set_peek_off = unix_set_peek_off,
857 .show_fdinfo = unix_show_fdinfo,
858};
859
860static const struct proto_ops unix_dgram_ops = {
861 .family = PF_UNIX,
862 .owner = THIS_MODULE,
863 .release = unix_release,
864 .bind = unix_bind,
865 .connect = unix_dgram_connect,
866 .socketpair = unix_socketpair,
867 .accept = sock_no_accept,
868 .getname = unix_getname,
869 .poll = unix_dgram_poll,
870 .ioctl = unix_ioctl,
871#ifdef CONFIG_COMPAT
872 .compat_ioctl = unix_compat_ioctl,
873#endif
874 .listen = sock_no_listen,
875 .shutdown = unix_shutdown,
876 .sendmsg = unix_dgram_sendmsg,
877 .read_skb = unix_read_skb,
878 .recvmsg = unix_dgram_recvmsg,
879 .mmap = sock_no_mmap,
880 .sendpage = sock_no_sendpage,
881 .set_peek_off = unix_set_peek_off,
882 .show_fdinfo = unix_show_fdinfo,
883};
884
885static const struct proto_ops unix_seqpacket_ops = {
886 .family = PF_UNIX,
887 .owner = THIS_MODULE,
888 .release = unix_release,
889 .bind = unix_bind,
890 .connect = unix_stream_connect,
891 .socketpair = unix_socketpair,
892 .accept = unix_accept,
893 .getname = unix_getname,
894 .poll = unix_dgram_poll,
895 .ioctl = unix_ioctl,
896#ifdef CONFIG_COMPAT
897 .compat_ioctl = unix_compat_ioctl,
898#endif
899 .listen = unix_listen,
900 .shutdown = unix_shutdown,
901 .sendmsg = unix_seqpacket_sendmsg,
902 .recvmsg = unix_seqpacket_recvmsg,
903 .mmap = sock_no_mmap,
904 .sendpage = sock_no_sendpage,
905 .set_peek_off = unix_set_peek_off,
906 .show_fdinfo = unix_show_fdinfo,
907};
908
909static void unix_close(struct sock *sk, long timeout)
910{
911 /* Nothing to do here, unix socket does not need a ->close().
912 * This is merely for sockmap.
913 */
914}
915
916static void unix_unhash(struct sock *sk)
917{
918 /* Nothing to do here, unix socket does not need a ->unhash().
919 * This is merely for sockmap.
920 */
921}
922
923struct proto unix_dgram_proto = {
924 .name = "UNIX",
925 .owner = THIS_MODULE,
926 .obj_size = sizeof(struct unix_sock),
927 .close = unix_close,
928#ifdef CONFIG_BPF_SYSCALL
929 .psock_update_sk_prot = unix_dgram_bpf_update_proto,
930#endif
931};
932
933struct proto unix_stream_proto = {
934 .name = "UNIX-STREAM",
935 .owner = THIS_MODULE,
936 .obj_size = sizeof(struct unix_sock),
937 .close = unix_close,
938 .unhash = unix_unhash,
939#ifdef CONFIG_BPF_SYSCALL
940 .psock_update_sk_prot = unix_stream_bpf_update_proto,
941#endif
942};
943
944static struct sock *unix_create1(struct net *net, struct socket *sock, int kern, int type)
945{
946 struct unix_sock *u;
947 struct sock *sk;
948 int err;
949
950 atomic_long_inc(&unix_nr_socks);
951 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) {
952 err = -ENFILE;
953 goto err;
954 }
955
956 if (type == SOCK_STREAM)
957 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_stream_proto, kern);
958 else /*dgram and seqpacket */
959 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_dgram_proto, kern);
960
961 if (!sk) {
962 err = -ENOMEM;
963 goto err;
964 }
965
966 sock_init_data(sock, sk);
967
968 sk->sk_hash = unix_unbound_hash(sk);
969 sk->sk_allocation = GFP_KERNEL_ACCOUNT;
970 sk->sk_write_space = unix_write_space;
971 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
972 sk->sk_destruct = unix_sock_destructor;
973 u = unix_sk(sk);
974 u->path.dentry = NULL;
975 u->path.mnt = NULL;
976 spin_lock_init(&u->lock);
977 atomic_long_set(&u->inflight, 0);
978 INIT_LIST_HEAD(&u->link);
979 mutex_init(&u->iolock); /* single task reading lock */
980 mutex_init(&u->bindlock); /* single task binding lock */
981 init_waitqueue_head(&u->peer_wait);
982 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
983 memset(&u->scm_stat, 0, sizeof(struct scm_stat));
984 unix_insert_unbound_socket(net, sk);
985
986 sock_prot_inuse_add(net, sk->sk_prot, 1);
987
988 return sk;
989
990err:
991 atomic_long_dec(&unix_nr_socks);
992 return ERR_PTR(err);
993}
994
995static int unix_create(struct net *net, struct socket *sock, int protocol,
996 int kern)
997{
998 struct sock *sk;
999
1000 if (protocol && protocol != PF_UNIX)
1001 return -EPROTONOSUPPORT;
1002
1003 sock->state = SS_UNCONNECTED;
1004
1005 switch (sock->type) {
1006 case SOCK_STREAM:
1007 sock->ops = &unix_stream_ops;
1008 break;
1009 /*
1010 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
1011 * nothing uses it.
1012 */
1013 case SOCK_RAW:
1014 sock->type = SOCK_DGRAM;
1015 fallthrough;
1016 case SOCK_DGRAM:
1017 sock->ops = &unix_dgram_ops;
1018 break;
1019 case SOCK_SEQPACKET:
1020 sock->ops = &unix_seqpacket_ops;
1021 break;
1022 default:
1023 return -ESOCKTNOSUPPORT;
1024 }
1025
1026 sk = unix_create1(net, sock, kern, sock->type);
1027 if (IS_ERR(sk))
1028 return PTR_ERR(sk);
1029
1030 return 0;
1031}
1032
1033static int unix_release(struct socket *sock)
1034{
1035 struct sock *sk = sock->sk;
1036
1037 if (!sk)
1038 return 0;
1039
1040 sk->sk_prot->close(sk, 0);
1041 unix_release_sock(sk, 0);
1042 sock->sk = NULL;
1043
1044 return 0;
1045}
1046
1047static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len,
1048 int type)
1049{
1050 struct inode *inode;
1051 struct path path;
1052 struct sock *sk;
1053 int err;
1054
1055 unix_mkname_bsd(sunaddr, addr_len);
1056 err = kern_path(sunaddr->sun_path, LOOKUP_FOLLOW, &path);
1057 if (err)
1058 goto fail;
1059
1060 err = path_permission(&path, MAY_WRITE);
1061 if (err)
1062 goto path_put;
1063
1064 err = -ECONNREFUSED;
1065 inode = d_backing_inode(path.dentry);
1066 if (!S_ISSOCK(inode->i_mode))
1067 goto path_put;
1068
1069 sk = unix_find_socket_byinode(inode);
1070 if (!sk)
1071 goto path_put;
1072
1073 err = -EPROTOTYPE;
1074 if (sk->sk_type == type)
1075 touch_atime(&path);
1076 else
1077 goto sock_put;
1078
1079 path_put(&path);
1080
1081 return sk;
1082
1083sock_put:
1084 sock_put(sk);
1085path_put:
1086 path_put(&path);
1087fail:
1088 return ERR_PTR(err);
1089}
1090
1091static struct sock *unix_find_abstract(struct net *net,
1092 struct sockaddr_un *sunaddr,
1093 int addr_len, int type)
1094{
1095 unsigned int hash = unix_abstract_hash(sunaddr, addr_len, type);
1096 struct dentry *dentry;
1097 struct sock *sk;
1098
1099 sk = unix_find_socket_byname(net, sunaddr, addr_len, hash);
1100 if (!sk)
1101 return ERR_PTR(-ECONNREFUSED);
1102
1103 dentry = unix_sk(sk)->path.dentry;
1104 if (dentry)
1105 touch_atime(&unix_sk(sk)->path);
1106
1107 return sk;
1108}
1109
1110static struct sock *unix_find_other(struct net *net,
1111 struct sockaddr_un *sunaddr,
1112 int addr_len, int type)
1113{
1114 struct sock *sk;
1115
1116 if (sunaddr->sun_path[0])
1117 sk = unix_find_bsd(sunaddr, addr_len, type);
1118 else
1119 sk = unix_find_abstract(net, sunaddr, addr_len, type);
1120
1121 return sk;
1122}
1123
1124static int unix_autobind(struct sock *sk)
1125{
1126 unsigned int new_hash, old_hash = sk->sk_hash;
1127 struct unix_sock *u = unix_sk(sk);
1128 struct net *net = sock_net(sk);
1129 struct unix_address *addr;
1130 u32 lastnum, ordernum;
1131 int err;
1132
1133 err = mutex_lock_interruptible(&u->bindlock);
1134 if (err)
1135 return err;
1136
1137 if (u->addr)
1138 goto out;
1139
1140 err = -ENOMEM;
1141 addr = kzalloc(sizeof(*addr) +
1142 offsetof(struct sockaddr_un, sun_path) + 16, GFP_KERNEL);
1143 if (!addr)
1144 goto out;
1145
1146 addr->len = offsetof(struct sockaddr_un, sun_path) + 6;
1147 addr->name->sun_family = AF_UNIX;
1148 refcount_set(&addr->refcnt, 1);
1149
1150 ordernum = get_random_u32();
1151 lastnum = ordernum & 0xFFFFF;
1152retry:
1153 ordernum = (ordernum + 1) & 0xFFFFF;
1154 sprintf(addr->name->sun_path + 1, "%05x", ordernum);
1155
1156 new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);
1157 unix_table_double_lock(net, old_hash, new_hash);
1158
1159 if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) {
1160 unix_table_double_unlock(net, old_hash, new_hash);
1161
1162 /* __unix_find_socket_byname() may take long time if many names
1163 * are already in use.
1164 */
1165 cond_resched();
1166
1167 if (ordernum == lastnum) {
1168 /* Give up if all names seems to be in use. */
1169 err = -ENOSPC;
1170 unix_release_addr(addr);
1171 goto out;
1172 }
1173
1174 goto retry;
1175 }
1176
1177 __unix_set_addr_hash(net, sk, addr, new_hash);
1178 unix_table_double_unlock(net, old_hash, new_hash);
1179 err = 0;
1180
1181out: mutex_unlock(&u->bindlock);
1182 return err;
1183}
1184
1185static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr,
1186 int addr_len)
1187{
1188 umode_t mode = S_IFSOCK |
1189 (SOCK_INODE(sk->sk_socket)->i_mode & ~current_umask());
1190 unsigned int new_hash, old_hash = sk->sk_hash;
1191 struct unix_sock *u = unix_sk(sk);
1192 struct net *net = sock_net(sk);
1193 struct user_namespace *ns; // barf...
1194 struct unix_address *addr;
1195 struct dentry *dentry;
1196 struct path parent;
1197 int err;
1198
1199 unix_mkname_bsd(sunaddr, addr_len);
1200 addr_len = strlen(sunaddr->sun_path) +
1201 offsetof(struct sockaddr_un, sun_path) + 1;
1202
1203 addr = unix_create_addr(sunaddr, addr_len);
1204 if (!addr)
1205 return -ENOMEM;
1206
1207 /*
1208 * Get the parent directory, calculate the hash for last
1209 * component.
1210 */
1211 dentry = kern_path_create(AT_FDCWD, addr->name->sun_path, &parent, 0);
1212 if (IS_ERR(dentry)) {
1213 err = PTR_ERR(dentry);
1214 goto out;
1215 }
1216
1217 /*
1218 * All right, let's create it.
1219 */
1220 ns = mnt_user_ns(parent.mnt);
1221 err = security_path_mknod(&parent, dentry, mode, 0);
1222 if (!err)
1223 err = vfs_mknod(ns, d_inode(parent.dentry), dentry, mode, 0);
1224 if (err)
1225 goto out_path;
1226 err = mutex_lock_interruptible(&u->bindlock);
1227 if (err)
1228 goto out_unlink;
1229 if (u->addr)
1230 goto out_unlock;
1231
1232 new_hash = unix_bsd_hash(d_backing_inode(dentry));
1233 unix_table_double_lock(net, old_hash, new_hash);
1234 u->path.mnt = mntget(parent.mnt);
1235 u->path.dentry = dget(dentry);
1236 __unix_set_addr_hash(net, sk, addr, new_hash);
1237 unix_table_double_unlock(net, old_hash, new_hash);
1238 unix_insert_bsd_socket(sk);
1239 mutex_unlock(&u->bindlock);
1240 done_path_create(&parent, dentry);
1241 return 0;
1242
1243out_unlock:
1244 mutex_unlock(&u->bindlock);
1245 err = -EINVAL;
1246out_unlink:
1247 /* failed after successful mknod? unlink what we'd created... */
1248 vfs_unlink(ns, d_inode(parent.dentry), dentry, NULL);
1249out_path:
1250 done_path_create(&parent, dentry);
1251out:
1252 unix_release_addr(addr);
1253 return err == -EEXIST ? -EADDRINUSE : err;
1254}
1255
1256static int unix_bind_abstract(struct sock *sk, struct sockaddr_un *sunaddr,
1257 int addr_len)
1258{
1259 unsigned int new_hash, old_hash = sk->sk_hash;
1260 struct unix_sock *u = unix_sk(sk);
1261 struct net *net = sock_net(sk);
1262 struct unix_address *addr;
1263 int err;
1264
1265 addr = unix_create_addr(sunaddr, addr_len);
1266 if (!addr)
1267 return -ENOMEM;
1268
1269 err = mutex_lock_interruptible(&u->bindlock);
1270 if (err)
1271 goto out;
1272
1273 if (u->addr) {
1274 err = -EINVAL;
1275 goto out_mutex;
1276 }
1277
1278 new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);
1279 unix_table_double_lock(net, old_hash, new_hash);
1280
1281 if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash))
1282 goto out_spin;
1283
1284 __unix_set_addr_hash(net, sk, addr, new_hash);
1285 unix_table_double_unlock(net, old_hash, new_hash);
1286 mutex_unlock(&u->bindlock);
1287 return 0;
1288
1289out_spin:
1290 unix_table_double_unlock(net, old_hash, new_hash);
1291 err = -EADDRINUSE;
1292out_mutex:
1293 mutex_unlock(&u->bindlock);
1294out:
1295 unix_release_addr(addr);
1296 return err;
1297}
1298
1299static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1300{
1301 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1302 struct sock *sk = sock->sk;
1303 int err;
1304
1305 if (addr_len == offsetof(struct sockaddr_un, sun_path) &&
1306 sunaddr->sun_family == AF_UNIX)
1307 return unix_autobind(sk);
1308
1309 err = unix_validate_addr(sunaddr, addr_len);
1310 if (err)
1311 return err;
1312
1313 if (sunaddr->sun_path[0])
1314 err = unix_bind_bsd(sk, sunaddr, addr_len);
1315 else
1316 err = unix_bind_abstract(sk, sunaddr, addr_len);
1317
1318 return err;
1319}
1320
1321static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1322{
1323 if (unlikely(sk1 == sk2) || !sk2) {
1324 unix_state_lock(sk1);
1325 return;
1326 }
1327 if (sk1 < sk2) {
1328 unix_state_lock(sk1);
1329 unix_state_lock_nested(sk2);
1330 } else {
1331 unix_state_lock(sk2);
1332 unix_state_lock_nested(sk1);
1333 }
1334}
1335
1336static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1337{
1338 if (unlikely(sk1 == sk2) || !sk2) {
1339 unix_state_unlock(sk1);
1340 return;
1341 }
1342 unix_state_unlock(sk1);
1343 unix_state_unlock(sk2);
1344}
1345
1346static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1347 int alen, int flags)
1348{
1349 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1350 struct sock *sk = sock->sk;
1351 struct sock *other;
1352 int err;
1353
1354 err = -EINVAL;
1355 if (alen < offsetofend(struct sockaddr, sa_family))
1356 goto out;
1357
1358 if (addr->sa_family != AF_UNSPEC) {
1359 err = unix_validate_addr(sunaddr, alen);
1360 if (err)
1361 goto out;
1362
1363 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1364 !unix_sk(sk)->addr) {
1365 err = unix_autobind(sk);
1366 if (err)
1367 goto out;
1368 }
1369
1370restart:
1371 other = unix_find_other(sock_net(sk), sunaddr, alen, sock->type);
1372 if (IS_ERR(other)) {
1373 err = PTR_ERR(other);
1374 goto out;
1375 }
1376
1377 unix_state_double_lock(sk, other);
1378
1379 /* Apparently VFS overslept socket death. Retry. */
1380 if (sock_flag(other, SOCK_DEAD)) {
1381 unix_state_double_unlock(sk, other);
1382 sock_put(other);
1383 goto restart;
1384 }
1385
1386 err = -EPERM;
1387 if (!unix_may_send(sk, other))
1388 goto out_unlock;
1389
1390 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1391 if (err)
1392 goto out_unlock;
1393
1394 sk->sk_state = other->sk_state = TCP_ESTABLISHED;
1395 } else {
1396 /*
1397 * 1003.1g breaking connected state with AF_UNSPEC
1398 */
1399 other = NULL;
1400 unix_state_double_lock(sk, other);
1401 }
1402
1403 /*
1404 * If it was connected, reconnect.
1405 */
1406 if (unix_peer(sk)) {
1407 struct sock *old_peer = unix_peer(sk);
1408
1409 unix_peer(sk) = other;
1410 if (!other)
1411 sk->sk_state = TCP_CLOSE;
1412 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1413
1414 unix_state_double_unlock(sk, other);
1415
1416 if (other != old_peer)
1417 unix_dgram_disconnected(sk, old_peer);
1418 sock_put(old_peer);
1419 } else {
1420 unix_peer(sk) = other;
1421 unix_state_double_unlock(sk, other);
1422 }
1423
1424 return 0;
1425
1426out_unlock:
1427 unix_state_double_unlock(sk, other);
1428 sock_put(other);
1429out:
1430 return err;
1431}
1432
1433static long unix_wait_for_peer(struct sock *other, long timeo)
1434 __releases(&unix_sk(other)->lock)
1435{
1436 struct unix_sock *u = unix_sk(other);
1437 int sched;
1438 DEFINE_WAIT(wait);
1439
1440 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1441
1442 sched = !sock_flag(other, SOCK_DEAD) &&
1443 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1444 unix_recvq_full(other);
1445
1446 unix_state_unlock(other);
1447
1448 if (sched)
1449 timeo = schedule_timeout(timeo);
1450
1451 finish_wait(&u->peer_wait, &wait);
1452 return timeo;
1453}
1454
1455static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1456 int addr_len, int flags)
1457{
1458 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1459 struct sock *sk = sock->sk, *newsk = NULL, *other = NULL;
1460 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1461 struct net *net = sock_net(sk);
1462 struct sk_buff *skb = NULL;
1463 long timeo;
1464 int err;
1465 int st;
1466
1467 err = unix_validate_addr(sunaddr, addr_len);
1468 if (err)
1469 goto out;
1470
1471 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr) {
1472 err = unix_autobind(sk);
1473 if (err)
1474 goto out;
1475 }
1476
1477 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1478
1479 /* First of all allocate resources.
1480 If we will make it after state is locked,
1481 we will have to recheck all again in any case.
1482 */
1483
1484 /* create new sock for complete connection */
1485 newsk = unix_create1(net, NULL, 0, sock->type);
1486 if (IS_ERR(newsk)) {
1487 err = PTR_ERR(newsk);
1488 newsk = NULL;
1489 goto out;
1490 }
1491
1492 err = -ENOMEM;
1493
1494 /* Allocate skb for sending to listening sock */
1495 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1496 if (skb == NULL)
1497 goto out;
1498
1499restart:
1500 /* Find listening sock. */
1501 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type);
1502 if (IS_ERR(other)) {
1503 err = PTR_ERR(other);
1504 other = NULL;
1505 goto out;
1506 }
1507
1508 /* Latch state of peer */
1509 unix_state_lock(other);
1510
1511 /* Apparently VFS overslept socket death. Retry. */
1512 if (sock_flag(other, SOCK_DEAD)) {
1513 unix_state_unlock(other);
1514 sock_put(other);
1515 goto restart;
1516 }
1517
1518 err = -ECONNREFUSED;
1519 if (other->sk_state != TCP_LISTEN)
1520 goto out_unlock;
1521 if (other->sk_shutdown & RCV_SHUTDOWN)
1522 goto out_unlock;
1523
1524 if (unix_recvq_full(other)) {
1525 err = -EAGAIN;
1526 if (!timeo)
1527 goto out_unlock;
1528
1529 timeo = unix_wait_for_peer(other, timeo);
1530
1531 err = sock_intr_errno(timeo);
1532 if (signal_pending(current))
1533 goto out;
1534 sock_put(other);
1535 goto restart;
1536 }
1537
1538 /* Latch our state.
1539
1540 It is tricky place. We need to grab our state lock and cannot
1541 drop lock on peer. It is dangerous because deadlock is
1542 possible. Connect to self case and simultaneous
1543 attempt to connect are eliminated by checking socket
1544 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1545 check this before attempt to grab lock.
1546
1547 Well, and we have to recheck the state after socket locked.
1548 */
1549 st = sk->sk_state;
1550
1551 switch (st) {
1552 case TCP_CLOSE:
1553 /* This is ok... continue with connect */
1554 break;
1555 case TCP_ESTABLISHED:
1556 /* Socket is already connected */
1557 err = -EISCONN;
1558 goto out_unlock;
1559 default:
1560 err = -EINVAL;
1561 goto out_unlock;
1562 }
1563
1564 unix_state_lock_nested(sk);
1565
1566 if (sk->sk_state != st) {
1567 unix_state_unlock(sk);
1568 unix_state_unlock(other);
1569 sock_put(other);
1570 goto restart;
1571 }
1572
1573 err = security_unix_stream_connect(sk, other, newsk);
1574 if (err) {
1575 unix_state_unlock(sk);
1576 goto out_unlock;
1577 }
1578
1579 /* The way is open! Fastly set all the necessary fields... */
1580
1581 sock_hold(sk);
1582 unix_peer(newsk) = sk;
1583 newsk->sk_state = TCP_ESTABLISHED;
1584 newsk->sk_type = sk->sk_type;
1585 init_peercred(newsk);
1586 newu = unix_sk(newsk);
1587 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1588 otheru = unix_sk(other);
1589
1590 /* copy address information from listening to new sock
1591 *
1592 * The contents of *(otheru->addr) and otheru->path
1593 * are seen fully set up here, since we have found
1594 * otheru in hash under its lock. Insertion into the
1595 * hash chain we'd found it in had been done in an
1596 * earlier critical area protected by the chain's lock,
1597 * the same one where we'd set *(otheru->addr) contents,
1598 * as well as otheru->path and otheru->addr itself.
1599 *
1600 * Using smp_store_release() here to set newu->addr
1601 * is enough to make those stores, as well as stores
1602 * to newu->path visible to anyone who gets newu->addr
1603 * by smp_load_acquire(). IOW, the same warranties
1604 * as for unix_sock instances bound in unix_bind() or
1605 * in unix_autobind().
1606 */
1607 if (otheru->path.dentry) {
1608 path_get(&otheru->path);
1609 newu->path = otheru->path;
1610 }
1611 refcount_inc(&otheru->addr->refcnt);
1612 smp_store_release(&newu->addr, otheru->addr);
1613
1614 /* Set credentials */
1615 copy_peercred(sk, other);
1616
1617 sock->state = SS_CONNECTED;
1618 sk->sk_state = TCP_ESTABLISHED;
1619 sock_hold(newsk);
1620
1621 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1622 unix_peer(sk) = newsk;
1623
1624 unix_state_unlock(sk);
1625
1626 /* take ten and send info to listening sock */
1627 spin_lock(&other->sk_receive_queue.lock);
1628 __skb_queue_tail(&other->sk_receive_queue, skb);
1629 spin_unlock(&other->sk_receive_queue.lock);
1630 unix_state_unlock(other);
1631 other->sk_data_ready(other);
1632 sock_put(other);
1633 return 0;
1634
1635out_unlock:
1636 if (other)
1637 unix_state_unlock(other);
1638
1639out:
1640 kfree_skb(skb);
1641 if (newsk)
1642 unix_release_sock(newsk, 0);
1643 if (other)
1644 sock_put(other);
1645 return err;
1646}
1647
1648static int unix_socketpair(struct socket *socka, struct socket *sockb)
1649{
1650 struct sock *ska = socka->sk, *skb = sockb->sk;
1651
1652 /* Join our sockets back to back */
1653 sock_hold(ska);
1654 sock_hold(skb);
1655 unix_peer(ska) = skb;
1656 unix_peer(skb) = ska;
1657 init_peercred(ska);
1658 init_peercred(skb);
1659
1660 ska->sk_state = TCP_ESTABLISHED;
1661 skb->sk_state = TCP_ESTABLISHED;
1662 socka->state = SS_CONNECTED;
1663 sockb->state = SS_CONNECTED;
1664 return 0;
1665}
1666
1667static void unix_sock_inherit_flags(const struct socket *old,
1668 struct socket *new)
1669{
1670 if (test_bit(SOCK_PASSCRED, &old->flags))
1671 set_bit(SOCK_PASSCRED, &new->flags);
1672 if (test_bit(SOCK_PASSSEC, &old->flags))
1673 set_bit(SOCK_PASSSEC, &new->flags);
1674}
1675
1676static int unix_accept(struct socket *sock, struct socket *newsock, int flags,
1677 bool kern)
1678{
1679 struct sock *sk = sock->sk;
1680 struct sock *tsk;
1681 struct sk_buff *skb;
1682 int err;
1683
1684 err = -EOPNOTSUPP;
1685 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1686 goto out;
1687
1688 err = -EINVAL;
1689 if (sk->sk_state != TCP_LISTEN)
1690 goto out;
1691
1692 /* If socket state is TCP_LISTEN it cannot change (for now...),
1693 * so that no locks are necessary.
1694 */
1695
1696 skb = skb_recv_datagram(sk, (flags & O_NONBLOCK) ? MSG_DONTWAIT : 0,
1697 &err);
1698 if (!skb) {
1699 /* This means receive shutdown. */
1700 if (err == 0)
1701 err = -EINVAL;
1702 goto out;
1703 }
1704
1705 tsk = skb->sk;
1706 skb_free_datagram(sk, skb);
1707 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1708
1709 /* attach accepted sock to socket */
1710 unix_state_lock(tsk);
1711 newsock->state = SS_CONNECTED;
1712 unix_sock_inherit_flags(sock, newsock);
1713 sock_graft(tsk, newsock);
1714 unix_state_unlock(tsk);
1715 return 0;
1716
1717out:
1718 return err;
1719}
1720
1721
1722static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1723{
1724 struct sock *sk = sock->sk;
1725 struct unix_address *addr;
1726 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1727 int err = 0;
1728
1729 if (peer) {
1730 sk = unix_peer_get(sk);
1731
1732 err = -ENOTCONN;
1733 if (!sk)
1734 goto out;
1735 err = 0;
1736 } else {
1737 sock_hold(sk);
1738 }
1739
1740 addr = smp_load_acquire(&unix_sk(sk)->addr);
1741 if (!addr) {
1742 sunaddr->sun_family = AF_UNIX;
1743 sunaddr->sun_path[0] = 0;
1744 err = offsetof(struct sockaddr_un, sun_path);
1745 } else {
1746 err = addr->len;
1747 memcpy(sunaddr, addr->name, addr->len);
1748 }
1749 sock_put(sk);
1750out:
1751 return err;
1752}
1753
1754static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb)
1755{
1756 scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1757
1758 /*
1759 * Garbage collection of unix sockets starts by selecting a set of
1760 * candidate sockets which have reference only from being in flight
1761 * (total_refs == inflight_refs). This condition is checked once during
1762 * the candidate collection phase, and candidates are marked as such, so
1763 * that non-candidates can later be ignored. While inflight_refs is
1764 * protected by unix_gc_lock, total_refs (file count) is not, hence this
1765 * is an instantaneous decision.
1766 *
1767 * Once a candidate, however, the socket must not be reinstalled into a
1768 * file descriptor while the garbage collection is in progress.
1769 *
1770 * If the above conditions are met, then the directed graph of
1771 * candidates (*) does not change while unix_gc_lock is held.
1772 *
1773 * Any operations that changes the file count through file descriptors
1774 * (dup, close, sendmsg) does not change the graph since candidates are
1775 * not installed in fds.
1776 *
1777 * Dequeing a candidate via recvmsg would install it into an fd, but
1778 * that takes unix_gc_lock to decrement the inflight count, so it's
1779 * serialized with garbage collection.
1780 *
1781 * MSG_PEEK is special in that it does not change the inflight count,
1782 * yet does install the socket into an fd. The following lock/unlock
1783 * pair is to ensure serialization with garbage collection. It must be
1784 * done between incrementing the file count and installing the file into
1785 * an fd.
1786 *
1787 * If garbage collection starts after the barrier provided by the
1788 * lock/unlock, then it will see the elevated refcount and not mark this
1789 * as a candidate. If a garbage collection is already in progress
1790 * before the file count was incremented, then the lock/unlock pair will
1791 * ensure that garbage collection is finished before progressing to
1792 * installing the fd.
1793 *
1794 * (*) A -> B where B is on the queue of A or B is on the queue of C
1795 * which is on the queue of listening socket A.
1796 */
1797 spin_lock(&unix_gc_lock);
1798 spin_unlock(&unix_gc_lock);
1799}
1800
1801static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1802{
1803 int err = 0;
1804
1805 UNIXCB(skb).pid = get_pid(scm->pid);
1806 UNIXCB(skb).uid = scm->creds.uid;
1807 UNIXCB(skb).gid = scm->creds.gid;
1808 UNIXCB(skb).fp = NULL;
1809 unix_get_secdata(scm, skb);
1810 if (scm->fp && send_fds)
1811 err = unix_attach_fds(scm, skb);
1812
1813 skb->destructor = unix_destruct_scm;
1814 return err;
1815}
1816
1817static bool unix_passcred_enabled(const struct socket *sock,
1818 const struct sock *other)
1819{
1820 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1821 !other->sk_socket ||
1822 test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1823}
1824
1825/*
1826 * Some apps rely on write() giving SCM_CREDENTIALS
1827 * We include credentials if source or destination socket
1828 * asserted SOCK_PASSCRED.
1829 */
1830static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1831 const struct sock *other)
1832{
1833 if (UNIXCB(skb).pid)
1834 return;
1835 if (unix_passcred_enabled(sock, other)) {
1836 UNIXCB(skb).pid = get_pid(task_tgid(current));
1837 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1838 }
1839}
1840
1841static int maybe_init_creds(struct scm_cookie *scm,
1842 struct socket *socket,
1843 const struct sock *other)
1844{
1845 int err;
1846 struct msghdr msg = { .msg_controllen = 0 };
1847
1848 err = scm_send(socket, &msg, scm, false);
1849 if (err)
1850 return err;
1851
1852 if (unix_passcred_enabled(socket, other)) {
1853 scm->pid = get_pid(task_tgid(current));
1854 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1855 }
1856 return err;
1857}
1858
1859static bool unix_skb_scm_eq(struct sk_buff *skb,
1860 struct scm_cookie *scm)
1861{
1862 return UNIXCB(skb).pid == scm->pid &&
1863 uid_eq(UNIXCB(skb).uid, scm->creds.uid) &&
1864 gid_eq(UNIXCB(skb).gid, scm->creds.gid) &&
1865 unix_secdata_eq(scm, skb);
1866}
1867
1868static void scm_stat_add(struct sock *sk, struct sk_buff *skb)
1869{
1870 struct scm_fp_list *fp = UNIXCB(skb).fp;
1871 struct unix_sock *u = unix_sk(sk);
1872
1873 if (unlikely(fp && fp->count))
1874 atomic_add(fp->count, &u->scm_stat.nr_fds);
1875}
1876
1877static void scm_stat_del(struct sock *sk, struct sk_buff *skb)
1878{
1879 struct scm_fp_list *fp = UNIXCB(skb).fp;
1880 struct unix_sock *u = unix_sk(sk);
1881
1882 if (unlikely(fp && fp->count))
1883 atomic_sub(fp->count, &u->scm_stat.nr_fds);
1884}
1885
1886/*
1887 * Send AF_UNIX data.
1888 */
1889
1890static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1891 size_t len)
1892{
1893 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1894 struct sock *sk = sock->sk, *other = NULL;
1895 struct unix_sock *u = unix_sk(sk);
1896 struct scm_cookie scm;
1897 struct sk_buff *skb;
1898 int data_len = 0;
1899 int sk_locked;
1900 long timeo;
1901 int err;
1902
1903 wait_for_unix_gc();
1904 err = scm_send(sock, msg, &scm, false);
1905 if (err < 0)
1906 return err;
1907
1908 err = -EOPNOTSUPP;
1909 if (msg->msg_flags&MSG_OOB)
1910 goto out;
1911
1912 if (msg->msg_namelen) {
1913 err = unix_validate_addr(sunaddr, msg->msg_namelen);
1914 if (err)
1915 goto out;
1916 } else {
1917 sunaddr = NULL;
1918 err = -ENOTCONN;
1919 other = unix_peer_get(sk);
1920 if (!other)
1921 goto out;
1922 }
1923
1924 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr) {
1925 err = unix_autobind(sk);
1926 if (err)
1927 goto out;
1928 }
1929
1930 err = -EMSGSIZE;
1931 if (len > sk->sk_sndbuf - 32)
1932 goto out;
1933
1934 if (len > SKB_MAX_ALLOC) {
1935 data_len = min_t(size_t,
1936 len - SKB_MAX_ALLOC,
1937 MAX_SKB_FRAGS * PAGE_SIZE);
1938 data_len = PAGE_ALIGN(data_len);
1939
1940 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1941 }
1942
1943 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1944 msg->msg_flags & MSG_DONTWAIT, &err,
1945 PAGE_ALLOC_COSTLY_ORDER);
1946 if (skb == NULL)
1947 goto out;
1948
1949 err = unix_scm_to_skb(&scm, skb, true);
1950 if (err < 0)
1951 goto out_free;
1952
1953 skb_put(skb, len - data_len);
1954 skb->data_len = data_len;
1955 skb->len = len;
1956 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1957 if (err)
1958 goto out_free;
1959
1960 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1961
1962restart:
1963 if (!other) {
1964 err = -ECONNRESET;
1965 if (sunaddr == NULL)
1966 goto out_free;
1967
1968 other = unix_find_other(sock_net(sk), sunaddr, msg->msg_namelen,
1969 sk->sk_type);
1970 if (IS_ERR(other)) {
1971 err = PTR_ERR(other);
1972 other = NULL;
1973 goto out_free;
1974 }
1975 }
1976
1977 if (sk_filter(other, skb) < 0) {
1978 /* Toss the packet but do not return any error to the sender */
1979 err = len;
1980 goto out_free;
1981 }
1982
1983 sk_locked = 0;
1984 unix_state_lock(other);
1985restart_locked:
1986 err = -EPERM;
1987 if (!unix_may_send(sk, other))
1988 goto out_unlock;
1989
1990 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1991 /*
1992 * Check with 1003.1g - what should
1993 * datagram error
1994 */
1995 unix_state_unlock(other);
1996 sock_put(other);
1997
1998 if (!sk_locked)
1999 unix_state_lock(sk);
2000
2001 err = 0;
2002 if (sk->sk_type == SOCK_SEQPACKET) {
2003 /* We are here only when racing with unix_release_sock()
2004 * is clearing @other. Never change state to TCP_CLOSE
2005 * unlike SOCK_DGRAM wants.
2006 */
2007 unix_state_unlock(sk);
2008 err = -EPIPE;
2009 } else if (unix_peer(sk) == other) {
2010 unix_peer(sk) = NULL;
2011 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
2012
2013 sk->sk_state = TCP_CLOSE;
2014 unix_state_unlock(sk);
2015
2016 unix_dgram_disconnected(sk, other);
2017 sock_put(other);
2018 err = -ECONNREFUSED;
2019 } else {
2020 unix_state_unlock(sk);
2021 }
2022
2023 other = NULL;
2024 if (err)
2025 goto out_free;
2026 goto restart;
2027 }
2028
2029 err = -EPIPE;
2030 if (other->sk_shutdown & RCV_SHUTDOWN)
2031 goto out_unlock;
2032
2033 if (sk->sk_type != SOCK_SEQPACKET) {
2034 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
2035 if (err)
2036 goto out_unlock;
2037 }
2038
2039 /* other == sk && unix_peer(other) != sk if
2040 * - unix_peer(sk) == NULL, destination address bound to sk
2041 * - unix_peer(sk) == sk by time of get but disconnected before lock
2042 */
2043 if (other != sk &&
2044 unlikely(unix_peer(other) != sk &&
2045 unix_recvq_full_lockless(other))) {
2046 if (timeo) {
2047 timeo = unix_wait_for_peer(other, timeo);
2048
2049 err = sock_intr_errno(timeo);
2050 if (signal_pending(current))
2051 goto out_free;
2052
2053 goto restart;
2054 }
2055
2056 if (!sk_locked) {
2057 unix_state_unlock(other);
2058 unix_state_double_lock(sk, other);
2059 }
2060
2061 if (unix_peer(sk) != other ||
2062 unix_dgram_peer_wake_me(sk, other)) {
2063 err = -EAGAIN;
2064 sk_locked = 1;
2065 goto out_unlock;
2066 }
2067
2068 if (!sk_locked) {
2069 sk_locked = 1;
2070 goto restart_locked;
2071 }
2072 }
2073
2074 if (unlikely(sk_locked))
2075 unix_state_unlock(sk);
2076
2077 if (sock_flag(other, SOCK_RCVTSTAMP))
2078 __net_timestamp(skb);
2079 maybe_add_creds(skb, sock, other);
2080 scm_stat_add(other, skb);
2081 skb_queue_tail(&other->sk_receive_queue, skb);
2082 unix_state_unlock(other);
2083 other->sk_data_ready(other);
2084 sock_put(other);
2085 scm_destroy(&scm);
2086 return len;
2087
2088out_unlock:
2089 if (sk_locked)
2090 unix_state_unlock(sk);
2091 unix_state_unlock(other);
2092out_free:
2093 kfree_skb(skb);
2094out:
2095 if (other)
2096 sock_put(other);
2097 scm_destroy(&scm);
2098 return err;
2099}
2100
2101/* We use paged skbs for stream sockets, and limit occupancy to 32768
2102 * bytes, and a minimum of a full page.
2103 */
2104#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
2105
2106#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2107static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other)
2108{
2109 struct unix_sock *ousk = unix_sk(other);
2110 struct sk_buff *skb;
2111 int err = 0;
2112
2113 skb = sock_alloc_send_skb(sock->sk, 1, msg->msg_flags & MSG_DONTWAIT, &err);
2114
2115 if (!skb)
2116 return err;
2117
2118 skb_put(skb, 1);
2119 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, 1);
2120
2121 if (err) {
2122 kfree_skb(skb);
2123 return err;
2124 }
2125
2126 unix_state_lock(other);
2127
2128 if (sock_flag(other, SOCK_DEAD) ||
2129 (other->sk_shutdown & RCV_SHUTDOWN)) {
2130 unix_state_unlock(other);
2131 kfree_skb(skb);
2132 return -EPIPE;
2133 }
2134
2135 maybe_add_creds(skb, sock, other);
2136 skb_get(skb);
2137
2138 if (ousk->oob_skb)
2139 consume_skb(ousk->oob_skb);
2140
2141 WRITE_ONCE(ousk->oob_skb, skb);
2142
2143 scm_stat_add(other, skb);
2144 skb_queue_tail(&other->sk_receive_queue, skb);
2145 sk_send_sigurg(other);
2146 unix_state_unlock(other);
2147 other->sk_data_ready(other);
2148
2149 return err;
2150}
2151#endif
2152
2153static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
2154 size_t len)
2155{
2156 struct sock *sk = sock->sk;
2157 struct sock *other = NULL;
2158 int err, size;
2159 struct sk_buff *skb;
2160 int sent = 0;
2161 struct scm_cookie scm;
2162 bool fds_sent = false;
2163 int data_len;
2164
2165 wait_for_unix_gc();
2166 err = scm_send(sock, msg, &scm, false);
2167 if (err < 0)
2168 return err;
2169
2170 err = -EOPNOTSUPP;
2171 if (msg->msg_flags & MSG_OOB) {
2172#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2173 if (len)
2174 len--;
2175 else
2176#endif
2177 goto out_err;
2178 }
2179
2180 if (msg->msg_namelen) {
2181 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
2182 goto out_err;
2183 } else {
2184 err = -ENOTCONN;
2185 other = unix_peer(sk);
2186 if (!other)
2187 goto out_err;
2188 }
2189
2190 if (sk->sk_shutdown & SEND_SHUTDOWN)
2191 goto pipe_err;
2192
2193 while (sent < len) {
2194 size = len - sent;
2195
2196 /* Keep two messages in the pipe so it schedules better */
2197 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
2198
2199 /* allow fallback to order-0 allocations */
2200 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
2201
2202 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
2203
2204 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
2205
2206 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
2207 msg->msg_flags & MSG_DONTWAIT, &err,
2208 get_order(UNIX_SKB_FRAGS_SZ));
2209 if (!skb)
2210 goto out_err;
2211
2212 /* Only send the fds in the first buffer */
2213 err = unix_scm_to_skb(&scm, skb, !fds_sent);
2214 if (err < 0) {
2215 kfree_skb(skb);
2216 goto out_err;
2217 }
2218 fds_sent = true;
2219
2220 skb_put(skb, size - data_len);
2221 skb->data_len = data_len;
2222 skb->len = size;
2223 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
2224 if (err) {
2225 kfree_skb(skb);
2226 goto out_err;
2227 }
2228
2229 unix_state_lock(other);
2230
2231 if (sock_flag(other, SOCK_DEAD) ||
2232 (other->sk_shutdown & RCV_SHUTDOWN))
2233 goto pipe_err_free;
2234
2235 maybe_add_creds(skb, sock, other);
2236 scm_stat_add(other, skb);
2237 skb_queue_tail(&other->sk_receive_queue, skb);
2238 unix_state_unlock(other);
2239 other->sk_data_ready(other);
2240 sent += size;
2241 }
2242
2243#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2244 if (msg->msg_flags & MSG_OOB) {
2245 err = queue_oob(sock, msg, other);
2246 if (err)
2247 goto out_err;
2248 sent++;
2249 }
2250#endif
2251
2252 scm_destroy(&scm);
2253
2254 return sent;
2255
2256pipe_err_free:
2257 unix_state_unlock(other);
2258 kfree_skb(skb);
2259pipe_err:
2260 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
2261 send_sig(SIGPIPE, current, 0);
2262 err = -EPIPE;
2263out_err:
2264 scm_destroy(&scm);
2265 return sent ? : err;
2266}
2267
2268static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
2269 int offset, size_t size, int flags)
2270{
2271 int err;
2272 bool send_sigpipe = false;
2273 bool init_scm = true;
2274 struct scm_cookie scm;
2275 struct sock *other, *sk = socket->sk;
2276 struct sk_buff *skb, *newskb = NULL, *tail = NULL;
2277
2278 if (flags & MSG_OOB)
2279 return -EOPNOTSUPP;
2280
2281 other = unix_peer(sk);
2282 if (!other || sk->sk_state != TCP_ESTABLISHED)
2283 return -ENOTCONN;
2284
2285 if (false) {
2286alloc_skb:
2287 unix_state_unlock(other);
2288 mutex_unlock(&unix_sk(other)->iolock);
2289 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
2290 &err, 0);
2291 if (!newskb)
2292 goto err;
2293 }
2294
2295 /* we must acquire iolock as we modify already present
2296 * skbs in the sk_receive_queue and mess with skb->len
2297 */
2298 err = mutex_lock_interruptible(&unix_sk(other)->iolock);
2299 if (err) {
2300 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
2301 goto err;
2302 }
2303
2304 if (sk->sk_shutdown & SEND_SHUTDOWN) {
2305 err = -EPIPE;
2306 send_sigpipe = true;
2307 goto err_unlock;
2308 }
2309
2310 unix_state_lock(other);
2311
2312 if (sock_flag(other, SOCK_DEAD) ||
2313 other->sk_shutdown & RCV_SHUTDOWN) {
2314 err = -EPIPE;
2315 send_sigpipe = true;
2316 goto err_state_unlock;
2317 }
2318
2319 if (init_scm) {
2320 err = maybe_init_creds(&scm, socket, other);
2321 if (err)
2322 goto err_state_unlock;
2323 init_scm = false;
2324 }
2325
2326 skb = skb_peek_tail(&other->sk_receive_queue);
2327 if (tail && tail == skb) {
2328 skb = newskb;
2329 } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
2330 if (newskb) {
2331 skb = newskb;
2332 } else {
2333 tail = skb;
2334 goto alloc_skb;
2335 }
2336 } else if (newskb) {
2337 /* this is fast path, we don't necessarily need to
2338 * call to kfree_skb even though with newskb == NULL
2339 * this - does no harm
2340 */
2341 consume_skb(newskb);
2342 newskb = NULL;
2343 }
2344
2345 if (skb_append_pagefrags(skb, page, offset, size)) {
2346 tail = skb;
2347 goto alloc_skb;
2348 }
2349
2350 skb->len += size;
2351 skb->data_len += size;
2352 skb->truesize += size;
2353 refcount_add(size, &sk->sk_wmem_alloc);
2354
2355 if (newskb) {
2356 err = unix_scm_to_skb(&scm, skb, false);
2357 if (err)
2358 goto err_state_unlock;
2359 spin_lock(&other->sk_receive_queue.lock);
2360 __skb_queue_tail(&other->sk_receive_queue, newskb);
2361 spin_unlock(&other->sk_receive_queue.lock);
2362 }
2363
2364 unix_state_unlock(other);
2365 mutex_unlock(&unix_sk(other)->iolock);
2366
2367 other->sk_data_ready(other);
2368 scm_destroy(&scm);
2369 return size;
2370
2371err_state_unlock:
2372 unix_state_unlock(other);
2373err_unlock:
2374 mutex_unlock(&unix_sk(other)->iolock);
2375err:
2376 kfree_skb(newskb);
2377 if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2378 send_sig(SIGPIPE, current, 0);
2379 if (!init_scm)
2380 scm_destroy(&scm);
2381 return err;
2382}
2383
2384static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2385 size_t len)
2386{
2387 int err;
2388 struct sock *sk = sock->sk;
2389
2390 err = sock_error(sk);
2391 if (err)
2392 return err;
2393
2394 if (sk->sk_state != TCP_ESTABLISHED)
2395 return -ENOTCONN;
2396
2397 if (msg->msg_namelen)
2398 msg->msg_namelen = 0;
2399
2400 return unix_dgram_sendmsg(sock, msg, len);
2401}
2402
2403static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2404 size_t size, int flags)
2405{
2406 struct sock *sk = sock->sk;
2407
2408 if (sk->sk_state != TCP_ESTABLISHED)
2409 return -ENOTCONN;
2410
2411 return unix_dgram_recvmsg(sock, msg, size, flags);
2412}
2413
2414static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2415{
2416 struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
2417
2418 if (addr) {
2419 msg->msg_namelen = addr->len;
2420 memcpy(msg->msg_name, addr->name, addr->len);
2421 }
2422}
2423
2424int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size,
2425 int flags)
2426{
2427 struct scm_cookie scm;
2428 struct socket *sock = sk->sk_socket;
2429 struct unix_sock *u = unix_sk(sk);
2430 struct sk_buff *skb, *last;
2431 long timeo;
2432 int skip;
2433 int err;
2434
2435 err = -EOPNOTSUPP;
2436 if (flags&MSG_OOB)
2437 goto out;
2438
2439 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2440
2441 do {
2442 mutex_lock(&u->iolock);
2443
2444 skip = sk_peek_offset(sk, flags);
2445 skb = __skb_try_recv_datagram(sk, &sk->sk_receive_queue, flags,
2446 &skip, &err, &last);
2447 if (skb) {
2448 if (!(flags & MSG_PEEK))
2449 scm_stat_del(sk, skb);
2450 break;
2451 }
2452
2453 mutex_unlock(&u->iolock);
2454
2455 if (err != -EAGAIN)
2456 break;
2457 } while (timeo &&
2458 !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue,
2459 &err, &timeo, last));
2460
2461 if (!skb) { /* implies iolock unlocked */
2462 unix_state_lock(sk);
2463 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2464 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2465 (sk->sk_shutdown & RCV_SHUTDOWN))
2466 err = 0;
2467 unix_state_unlock(sk);
2468 goto out;
2469 }
2470
2471 if (wq_has_sleeper(&u->peer_wait))
2472 wake_up_interruptible_sync_poll(&u->peer_wait,
2473 EPOLLOUT | EPOLLWRNORM |
2474 EPOLLWRBAND);
2475
2476 if (msg->msg_name)
2477 unix_copy_addr(msg, skb->sk);
2478
2479 if (size > skb->len - skip)
2480 size = skb->len - skip;
2481 else if (size < skb->len - skip)
2482 msg->msg_flags |= MSG_TRUNC;
2483
2484 err = skb_copy_datagram_msg(skb, skip, msg, size);
2485 if (err)
2486 goto out_free;
2487
2488 if (sock_flag(sk, SOCK_RCVTSTAMP))
2489 __sock_recv_timestamp(msg, sk, skb);
2490
2491 memset(&scm, 0, sizeof(scm));
2492
2493 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2494 unix_set_secdata(&scm, skb);
2495
2496 if (!(flags & MSG_PEEK)) {
2497 if (UNIXCB(skb).fp)
2498 unix_detach_fds(&scm, skb);
2499
2500 sk_peek_offset_bwd(sk, skb->len);
2501 } else {
2502 /* It is questionable: on PEEK we could:
2503 - do not return fds - good, but too simple 8)
2504 - return fds, and do not return them on read (old strategy,
2505 apparently wrong)
2506 - clone fds (I chose it for now, it is the most universal
2507 solution)
2508
2509 POSIX 1003.1g does not actually define this clearly
2510 at all. POSIX 1003.1g doesn't define a lot of things
2511 clearly however!
2512
2513 */
2514
2515 sk_peek_offset_fwd(sk, size);
2516
2517 if (UNIXCB(skb).fp)
2518 unix_peek_fds(&scm, skb);
2519 }
2520 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2521
2522 scm_recv(sock, msg, &scm, flags);
2523
2524out_free:
2525 skb_free_datagram(sk, skb);
2526 mutex_unlock(&u->iolock);
2527out:
2528 return err;
2529}
2530
2531static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
2532 int flags)
2533{
2534 struct sock *sk = sock->sk;
2535
2536#ifdef CONFIG_BPF_SYSCALL
2537 const struct proto *prot = READ_ONCE(sk->sk_prot);
2538
2539 if (prot != &unix_dgram_proto)
2540 return prot->recvmsg(sk, msg, size, flags, NULL);
2541#endif
2542 return __unix_dgram_recvmsg(sk, msg, size, flags);
2543}
2544
2545static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
2546{
2547 struct unix_sock *u = unix_sk(sk);
2548 struct sk_buff *skb;
2549 int err, copied;
2550
2551 mutex_lock(&u->iolock);
2552 skb = skb_recv_datagram(sk, MSG_DONTWAIT, &err);
2553 mutex_unlock(&u->iolock);
2554 if (!skb)
2555 return err;
2556
2557 copied = recv_actor(sk, skb);
2558 kfree_skb(skb);
2559
2560 return copied;
2561}
2562
2563/*
2564 * Sleep until more data has arrived. But check for races..
2565 */
2566static long unix_stream_data_wait(struct sock *sk, long timeo,
2567 struct sk_buff *last, unsigned int last_len,
2568 bool freezable)
2569{
2570 unsigned int state = TASK_INTERRUPTIBLE | freezable * TASK_FREEZABLE;
2571 struct sk_buff *tail;
2572 DEFINE_WAIT(wait);
2573
2574 unix_state_lock(sk);
2575
2576 for (;;) {
2577 prepare_to_wait(sk_sleep(sk), &wait, state);
2578
2579 tail = skb_peek_tail(&sk->sk_receive_queue);
2580 if (tail != last ||
2581 (tail && tail->len != last_len) ||
2582 sk->sk_err ||
2583 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2584 signal_pending(current) ||
2585 !timeo)
2586 break;
2587
2588 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2589 unix_state_unlock(sk);
2590 timeo = schedule_timeout(timeo);
2591 unix_state_lock(sk);
2592
2593 if (sock_flag(sk, SOCK_DEAD))
2594 break;
2595
2596 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2597 }
2598
2599 finish_wait(sk_sleep(sk), &wait);
2600 unix_state_unlock(sk);
2601 return timeo;
2602}
2603
2604static unsigned int unix_skb_len(const struct sk_buff *skb)
2605{
2606 return skb->len - UNIXCB(skb).consumed;
2607}
2608
2609struct unix_stream_read_state {
2610 int (*recv_actor)(struct sk_buff *, int, int,
2611 struct unix_stream_read_state *);
2612 struct socket *socket;
2613 struct msghdr *msg;
2614 struct pipe_inode_info *pipe;
2615 size_t size;
2616 int flags;
2617 unsigned int splice_flags;
2618};
2619
2620#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2621static int unix_stream_recv_urg(struct unix_stream_read_state *state)
2622{
2623 struct socket *sock = state->socket;
2624 struct sock *sk = sock->sk;
2625 struct unix_sock *u = unix_sk(sk);
2626 int chunk = 1;
2627 struct sk_buff *oob_skb;
2628
2629 mutex_lock(&u->iolock);
2630 unix_state_lock(sk);
2631
2632 if (sock_flag(sk, SOCK_URGINLINE) || !u->oob_skb) {
2633 unix_state_unlock(sk);
2634 mutex_unlock(&u->iolock);
2635 return -EINVAL;
2636 }
2637
2638 oob_skb = u->oob_skb;
2639
2640 if (!(state->flags & MSG_PEEK))
2641 WRITE_ONCE(u->oob_skb, NULL);
2642
2643 unix_state_unlock(sk);
2644
2645 chunk = state->recv_actor(oob_skb, 0, chunk, state);
2646
2647 if (!(state->flags & MSG_PEEK)) {
2648 UNIXCB(oob_skb).consumed += 1;
2649 kfree_skb(oob_skb);
2650 }
2651
2652 mutex_unlock(&u->iolock);
2653
2654 if (chunk < 0)
2655 return -EFAULT;
2656
2657 state->msg->msg_flags |= MSG_OOB;
2658 return 1;
2659}
2660
2661static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
2662 int flags, int copied)
2663{
2664 struct unix_sock *u = unix_sk(sk);
2665
2666 if (!unix_skb_len(skb) && !(flags & MSG_PEEK)) {
2667 skb_unlink(skb, &sk->sk_receive_queue);
2668 consume_skb(skb);
2669 skb = NULL;
2670 } else {
2671 if (skb == u->oob_skb) {
2672 if (copied) {
2673 skb = NULL;
2674 } else if (sock_flag(sk, SOCK_URGINLINE)) {
2675 if (!(flags & MSG_PEEK)) {
2676 WRITE_ONCE(u->oob_skb, NULL);
2677 consume_skb(skb);
2678 }
2679 } else if (!(flags & MSG_PEEK)) {
2680 skb_unlink(skb, &sk->sk_receive_queue);
2681 consume_skb(skb);
2682 skb = skb_peek(&sk->sk_receive_queue);
2683 }
2684 }
2685 }
2686 return skb;
2687}
2688#endif
2689
2690static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
2691{
2692 if (unlikely(sk->sk_state != TCP_ESTABLISHED))
2693 return -ENOTCONN;
2694
2695 return unix_read_skb(sk, recv_actor);
2696}
2697
2698static int unix_stream_read_generic(struct unix_stream_read_state *state,
2699 bool freezable)
2700{
2701 struct scm_cookie scm;
2702 struct socket *sock = state->socket;
2703 struct sock *sk = sock->sk;
2704 struct unix_sock *u = unix_sk(sk);
2705 int copied = 0;
2706 int flags = state->flags;
2707 int noblock = flags & MSG_DONTWAIT;
2708 bool check_creds = false;
2709 int target;
2710 int err = 0;
2711 long timeo;
2712 int skip;
2713 size_t size = state->size;
2714 unsigned int last_len;
2715
2716 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2717 err = -EINVAL;
2718 goto out;
2719 }
2720
2721 if (unlikely(flags & MSG_OOB)) {
2722 err = -EOPNOTSUPP;
2723#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2724 err = unix_stream_recv_urg(state);
2725#endif
2726 goto out;
2727 }
2728
2729 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2730 timeo = sock_rcvtimeo(sk, noblock);
2731
2732 memset(&scm, 0, sizeof(scm));
2733
2734 /* Lock the socket to prevent queue disordering
2735 * while sleeps in memcpy_tomsg
2736 */
2737 mutex_lock(&u->iolock);
2738
2739 skip = max(sk_peek_offset(sk, flags), 0);
2740
2741 do {
2742 int chunk;
2743 bool drop_skb;
2744 struct sk_buff *skb, *last;
2745
2746redo:
2747 unix_state_lock(sk);
2748 if (sock_flag(sk, SOCK_DEAD)) {
2749 err = -ECONNRESET;
2750 goto unlock;
2751 }
2752 last = skb = skb_peek(&sk->sk_receive_queue);
2753 last_len = last ? last->len : 0;
2754
2755#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2756 if (skb) {
2757 skb = manage_oob(skb, sk, flags, copied);
2758 if (!skb) {
2759 unix_state_unlock(sk);
2760 if (copied)
2761 break;
2762 goto redo;
2763 }
2764 }
2765#endif
2766again:
2767 if (skb == NULL) {
2768 if (copied >= target)
2769 goto unlock;
2770
2771 /*
2772 * POSIX 1003.1g mandates this order.
2773 */
2774
2775 err = sock_error(sk);
2776 if (err)
2777 goto unlock;
2778 if (sk->sk_shutdown & RCV_SHUTDOWN)
2779 goto unlock;
2780
2781 unix_state_unlock(sk);
2782 if (!timeo) {
2783 err = -EAGAIN;
2784 break;
2785 }
2786
2787 mutex_unlock(&u->iolock);
2788
2789 timeo = unix_stream_data_wait(sk, timeo, last,
2790 last_len, freezable);
2791
2792 if (signal_pending(current)) {
2793 err = sock_intr_errno(timeo);
2794 scm_destroy(&scm);
2795 goto out;
2796 }
2797
2798 mutex_lock(&u->iolock);
2799 goto redo;
2800unlock:
2801 unix_state_unlock(sk);
2802 break;
2803 }
2804
2805 while (skip >= unix_skb_len(skb)) {
2806 skip -= unix_skb_len(skb);
2807 last = skb;
2808 last_len = skb->len;
2809 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2810 if (!skb)
2811 goto again;
2812 }
2813
2814 unix_state_unlock(sk);
2815
2816 if (check_creds) {
2817 /* Never glue messages from different writers */
2818 if (!unix_skb_scm_eq(skb, &scm))
2819 break;
2820 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2821 /* Copy credentials */
2822 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2823 unix_set_secdata(&scm, skb);
2824 check_creds = true;
2825 }
2826
2827 /* Copy address just once */
2828 if (state->msg && state->msg->msg_name) {
2829 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2830 state->msg->msg_name);
2831 unix_copy_addr(state->msg, skb->sk);
2832 sunaddr = NULL;
2833 }
2834
2835 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2836 skb_get(skb);
2837 chunk = state->recv_actor(skb, skip, chunk, state);
2838 drop_skb = !unix_skb_len(skb);
2839 /* skb is only safe to use if !drop_skb */
2840 consume_skb(skb);
2841 if (chunk < 0) {
2842 if (copied == 0)
2843 copied = -EFAULT;
2844 break;
2845 }
2846 copied += chunk;
2847 size -= chunk;
2848
2849 if (drop_skb) {
2850 /* the skb was touched by a concurrent reader;
2851 * we should not expect anything from this skb
2852 * anymore and assume it invalid - we can be
2853 * sure it was dropped from the socket queue
2854 *
2855 * let's report a short read
2856 */
2857 err = 0;
2858 break;
2859 }
2860
2861 /* Mark read part of skb as used */
2862 if (!(flags & MSG_PEEK)) {
2863 UNIXCB(skb).consumed += chunk;
2864
2865 sk_peek_offset_bwd(sk, chunk);
2866
2867 if (UNIXCB(skb).fp) {
2868 scm_stat_del(sk, skb);
2869 unix_detach_fds(&scm, skb);
2870 }
2871
2872 if (unix_skb_len(skb))
2873 break;
2874
2875 skb_unlink(skb, &sk->sk_receive_queue);
2876 consume_skb(skb);
2877
2878 if (scm.fp)
2879 break;
2880 } else {
2881 /* It is questionable, see note in unix_dgram_recvmsg.
2882 */
2883 if (UNIXCB(skb).fp)
2884 unix_peek_fds(&scm, skb);
2885
2886 sk_peek_offset_fwd(sk, chunk);
2887
2888 if (UNIXCB(skb).fp)
2889 break;
2890
2891 skip = 0;
2892 last = skb;
2893 last_len = skb->len;
2894 unix_state_lock(sk);
2895 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2896 if (skb)
2897 goto again;
2898 unix_state_unlock(sk);
2899 break;
2900 }
2901 } while (size);
2902
2903 mutex_unlock(&u->iolock);
2904 if (state->msg)
2905 scm_recv(sock, state->msg, &scm, flags);
2906 else
2907 scm_destroy(&scm);
2908out:
2909 return copied ? : err;
2910}
2911
2912static int unix_stream_read_actor(struct sk_buff *skb,
2913 int skip, int chunk,
2914 struct unix_stream_read_state *state)
2915{
2916 int ret;
2917
2918 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2919 state->msg, chunk);
2920 return ret ?: chunk;
2921}
2922
2923int __unix_stream_recvmsg(struct sock *sk, struct msghdr *msg,
2924 size_t size, int flags)
2925{
2926 struct unix_stream_read_state state = {
2927 .recv_actor = unix_stream_read_actor,
2928 .socket = sk->sk_socket,
2929 .msg = msg,
2930 .size = size,
2931 .flags = flags
2932 };
2933
2934 return unix_stream_read_generic(&state, true);
2935}
2936
2937static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2938 size_t size, int flags)
2939{
2940 struct unix_stream_read_state state = {
2941 .recv_actor = unix_stream_read_actor,
2942 .socket = sock,
2943 .msg = msg,
2944 .size = size,
2945 .flags = flags
2946 };
2947
2948#ifdef CONFIG_BPF_SYSCALL
2949 struct sock *sk = sock->sk;
2950 const struct proto *prot = READ_ONCE(sk->sk_prot);
2951
2952 if (prot != &unix_stream_proto)
2953 return prot->recvmsg(sk, msg, size, flags, NULL);
2954#endif
2955 return unix_stream_read_generic(&state, true);
2956}
2957
2958static int unix_stream_splice_actor(struct sk_buff *skb,
2959 int skip, int chunk,
2960 struct unix_stream_read_state *state)
2961{
2962 return skb_splice_bits(skb, state->socket->sk,
2963 UNIXCB(skb).consumed + skip,
2964 state->pipe, chunk, state->splice_flags);
2965}
2966
2967static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2968 struct pipe_inode_info *pipe,
2969 size_t size, unsigned int flags)
2970{
2971 struct unix_stream_read_state state = {
2972 .recv_actor = unix_stream_splice_actor,
2973 .socket = sock,
2974 .pipe = pipe,
2975 .size = size,
2976 .splice_flags = flags,
2977 };
2978
2979 if (unlikely(*ppos))
2980 return -ESPIPE;
2981
2982 if (sock->file->f_flags & O_NONBLOCK ||
2983 flags & SPLICE_F_NONBLOCK)
2984 state.flags = MSG_DONTWAIT;
2985
2986 return unix_stream_read_generic(&state, false);
2987}
2988
2989static int unix_shutdown(struct socket *sock, int mode)
2990{
2991 struct sock *sk = sock->sk;
2992 struct sock *other;
2993
2994 if (mode < SHUT_RD || mode > SHUT_RDWR)
2995 return -EINVAL;
2996 /* This maps:
2997 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2998 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2999 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
3000 */
3001 ++mode;
3002
3003 unix_state_lock(sk);
3004 sk->sk_shutdown |= mode;
3005 other = unix_peer(sk);
3006 if (other)
3007 sock_hold(other);
3008 unix_state_unlock(sk);
3009 sk->sk_state_change(sk);
3010
3011 if (other &&
3012 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
3013
3014 int peer_mode = 0;
3015 const struct proto *prot = READ_ONCE(other->sk_prot);
3016
3017 if (prot->unhash)
3018 prot->unhash(other);
3019 if (mode&RCV_SHUTDOWN)
3020 peer_mode |= SEND_SHUTDOWN;
3021 if (mode&SEND_SHUTDOWN)
3022 peer_mode |= RCV_SHUTDOWN;
3023 unix_state_lock(other);
3024 other->sk_shutdown |= peer_mode;
3025 unix_state_unlock(other);
3026 other->sk_state_change(other);
3027 if (peer_mode == SHUTDOWN_MASK)
3028 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
3029 else if (peer_mode & RCV_SHUTDOWN)
3030 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
3031 }
3032 if (other)
3033 sock_put(other);
3034
3035 return 0;
3036}
3037
3038long unix_inq_len(struct sock *sk)
3039{
3040 struct sk_buff *skb;
3041 long amount = 0;
3042
3043 if (sk->sk_state == TCP_LISTEN)
3044 return -EINVAL;
3045
3046 spin_lock(&sk->sk_receive_queue.lock);
3047 if (sk->sk_type == SOCK_STREAM ||
3048 sk->sk_type == SOCK_SEQPACKET) {
3049 skb_queue_walk(&sk->sk_receive_queue, skb)
3050 amount += unix_skb_len(skb);
3051 } else {
3052 skb = skb_peek(&sk->sk_receive_queue);
3053 if (skb)
3054 amount = skb->len;
3055 }
3056 spin_unlock(&sk->sk_receive_queue.lock);
3057
3058 return amount;
3059}
3060EXPORT_SYMBOL_GPL(unix_inq_len);
3061
3062long unix_outq_len(struct sock *sk)
3063{
3064 return sk_wmem_alloc_get(sk);
3065}
3066EXPORT_SYMBOL_GPL(unix_outq_len);
3067
3068static int unix_open_file(struct sock *sk)
3069{
3070 struct path path;
3071 struct file *f;
3072 int fd;
3073
3074 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
3075 return -EPERM;
3076
3077 if (!smp_load_acquire(&unix_sk(sk)->addr))
3078 return -ENOENT;
3079
3080 path = unix_sk(sk)->path;
3081 if (!path.dentry)
3082 return -ENOENT;
3083
3084 path_get(&path);
3085
3086 fd = get_unused_fd_flags(O_CLOEXEC);
3087 if (fd < 0)
3088 goto out;
3089
3090 f = dentry_open(&path, O_PATH, current_cred());
3091 if (IS_ERR(f)) {
3092 put_unused_fd(fd);
3093 fd = PTR_ERR(f);
3094 goto out;
3095 }
3096
3097 fd_install(fd, f);
3098out:
3099 path_put(&path);
3100
3101 return fd;
3102}
3103
3104static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
3105{
3106 struct sock *sk = sock->sk;
3107 long amount = 0;
3108 int err;
3109
3110 switch (cmd) {
3111 case SIOCOUTQ:
3112 amount = unix_outq_len(sk);
3113 err = put_user(amount, (int __user *)arg);
3114 break;
3115 case SIOCINQ:
3116 amount = unix_inq_len(sk);
3117 if (amount < 0)
3118 err = amount;
3119 else
3120 err = put_user(amount, (int __user *)arg);
3121 break;
3122 case SIOCUNIXFILE:
3123 err = unix_open_file(sk);
3124 break;
3125#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
3126 case SIOCATMARK:
3127 {
3128 struct sk_buff *skb;
3129 int answ = 0;
3130
3131 skb = skb_peek(&sk->sk_receive_queue);
3132 if (skb && skb == READ_ONCE(unix_sk(sk)->oob_skb))
3133 answ = 1;
3134 err = put_user(answ, (int __user *)arg);
3135 }
3136 break;
3137#endif
3138 default:
3139 err = -ENOIOCTLCMD;
3140 break;
3141 }
3142 return err;
3143}
3144
3145#ifdef CONFIG_COMPAT
3146static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
3147{
3148 return unix_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
3149}
3150#endif
3151
3152static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait)
3153{
3154 struct sock *sk = sock->sk;
3155 __poll_t mask;
3156
3157 sock_poll_wait(file, sock, wait);
3158 mask = 0;
3159
3160 /* exceptional events? */
3161 if (sk->sk_err)
3162 mask |= EPOLLERR;
3163 if (sk->sk_shutdown == SHUTDOWN_MASK)
3164 mask |= EPOLLHUP;
3165 if (sk->sk_shutdown & RCV_SHUTDOWN)
3166 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
3167
3168 /* readable? */
3169 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
3170 mask |= EPOLLIN | EPOLLRDNORM;
3171 if (sk_is_readable(sk))
3172 mask |= EPOLLIN | EPOLLRDNORM;
3173#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
3174 if (READ_ONCE(unix_sk(sk)->oob_skb))
3175 mask |= EPOLLPRI;
3176#endif
3177
3178 /* Connection-based need to check for termination and startup */
3179 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
3180 sk->sk_state == TCP_CLOSE)
3181 mask |= EPOLLHUP;
3182
3183 /*
3184 * we set writable also when the other side has shut down the
3185 * connection. This prevents stuck sockets.
3186 */
3187 if (unix_writable(sk))
3188 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
3189
3190 return mask;
3191}
3192
3193static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
3194 poll_table *wait)
3195{
3196 struct sock *sk = sock->sk, *other;
3197 unsigned int writable;
3198 __poll_t mask;
3199
3200 sock_poll_wait(file, sock, wait);
3201 mask = 0;
3202
3203 /* exceptional events? */
3204 if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
3205 mask |= EPOLLERR |
3206 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
3207
3208 if (sk->sk_shutdown & RCV_SHUTDOWN)
3209 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
3210 if (sk->sk_shutdown == SHUTDOWN_MASK)
3211 mask |= EPOLLHUP;
3212
3213 /* readable? */
3214 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
3215 mask |= EPOLLIN | EPOLLRDNORM;
3216 if (sk_is_readable(sk))
3217 mask |= EPOLLIN | EPOLLRDNORM;
3218
3219 /* Connection-based need to check for termination and startup */
3220 if (sk->sk_type == SOCK_SEQPACKET) {
3221 if (sk->sk_state == TCP_CLOSE)
3222 mask |= EPOLLHUP;
3223 /* connection hasn't started yet? */
3224 if (sk->sk_state == TCP_SYN_SENT)
3225 return mask;
3226 }
3227
3228 /* No write status requested, avoid expensive OUT tests. */
3229 if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT)))
3230 return mask;
3231
3232 writable = unix_writable(sk);
3233 if (writable) {
3234 unix_state_lock(sk);
3235
3236 other = unix_peer(sk);
3237 if (other && unix_peer(other) != sk &&
3238 unix_recvq_full_lockless(other) &&
3239 unix_dgram_peer_wake_me(sk, other))
3240 writable = 0;
3241
3242 unix_state_unlock(sk);
3243 }
3244
3245 if (writable)
3246 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
3247 else
3248 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
3249
3250 return mask;
3251}
3252
3253#ifdef CONFIG_PROC_FS
3254
3255#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
3256
3257#define get_bucket(x) ((x) >> BUCKET_SPACE)
3258#define get_offset(x) ((x) & ((1UL << BUCKET_SPACE) - 1))
3259#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
3260
3261static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
3262{
3263 unsigned long offset = get_offset(*pos);
3264 unsigned long bucket = get_bucket(*pos);
3265 unsigned long count = 0;
3266 struct sock *sk;
3267
3268 for (sk = sk_head(&seq_file_net(seq)->unx.table.buckets[bucket]);
3269 sk; sk = sk_next(sk)) {
3270 if (++count == offset)
3271 break;
3272 }
3273
3274 return sk;
3275}
3276
3277static struct sock *unix_get_first(struct seq_file *seq, loff_t *pos)
3278{
3279 unsigned long bucket = get_bucket(*pos);
3280 struct net *net = seq_file_net(seq);
3281 struct sock *sk;
3282
3283 while (bucket < UNIX_HASH_SIZE) {
3284 spin_lock(&net->unx.table.locks[bucket]);
3285
3286 sk = unix_from_bucket(seq, pos);
3287 if (sk)
3288 return sk;
3289
3290 spin_unlock(&net->unx.table.locks[bucket]);
3291
3292 *pos = set_bucket_offset(++bucket, 1);
3293 }
3294
3295 return NULL;
3296}
3297
3298static struct sock *unix_get_next(struct seq_file *seq, struct sock *sk,
3299 loff_t *pos)
3300{
3301 unsigned long bucket = get_bucket(*pos);
3302
3303 sk = sk_next(sk);
3304 if (sk)
3305 return sk;
3306
3307
3308 spin_unlock(&seq_file_net(seq)->unx.table.locks[bucket]);
3309
3310 *pos = set_bucket_offset(++bucket, 1);
3311
3312 return unix_get_first(seq, pos);
3313}
3314
3315static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
3316{
3317 if (!*pos)
3318 return SEQ_START_TOKEN;
3319
3320 return unix_get_first(seq, pos);
3321}
3322
3323static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3324{
3325 ++*pos;
3326
3327 if (v == SEQ_START_TOKEN)
3328 return unix_get_first(seq, pos);
3329
3330 return unix_get_next(seq, v, pos);
3331}
3332
3333static void unix_seq_stop(struct seq_file *seq, void *v)
3334{
3335 struct sock *sk = v;
3336
3337 if (sk)
3338 spin_unlock(&seq_file_net(seq)->unx.table.locks[sk->sk_hash]);
3339}
3340
3341static int unix_seq_show(struct seq_file *seq, void *v)
3342{
3343
3344 if (v == SEQ_START_TOKEN)
3345 seq_puts(seq, "Num RefCount Protocol Flags Type St "
3346 "Inode Path\n");
3347 else {
3348 struct sock *s = v;
3349 struct unix_sock *u = unix_sk(s);
3350 unix_state_lock(s);
3351
3352 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
3353 s,
3354 refcount_read(&s->sk_refcnt),
3355 0,
3356 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
3357 s->sk_type,
3358 s->sk_socket ?
3359 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
3360 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
3361 sock_i_ino(s));
3362
3363 if (u->addr) { // under a hash table lock here
3364 int i, len;
3365 seq_putc(seq, ' ');
3366
3367 i = 0;
3368 len = u->addr->len -
3369 offsetof(struct sockaddr_un, sun_path);
3370 if (u->addr->name->sun_path[0]) {
3371 len--;
3372 } else {
3373 seq_putc(seq, '@');
3374 i++;
3375 }
3376 for ( ; i < len; i++)
3377 seq_putc(seq, u->addr->name->sun_path[i] ?:
3378 '@');
3379 }
3380 unix_state_unlock(s);
3381 seq_putc(seq, '\n');
3382 }
3383
3384 return 0;
3385}
3386
3387static const struct seq_operations unix_seq_ops = {
3388 .start = unix_seq_start,
3389 .next = unix_seq_next,
3390 .stop = unix_seq_stop,
3391 .show = unix_seq_show,
3392};
3393
3394#if IS_BUILTIN(CONFIG_UNIX) && defined(CONFIG_BPF_SYSCALL)
3395struct bpf_unix_iter_state {
3396 struct seq_net_private p;
3397 unsigned int cur_sk;
3398 unsigned int end_sk;
3399 unsigned int max_sk;
3400 struct sock **batch;
3401 bool st_bucket_done;
3402};
3403
3404struct bpf_iter__unix {
3405 __bpf_md_ptr(struct bpf_iter_meta *, meta);
3406 __bpf_md_ptr(struct unix_sock *, unix_sk);
3407 uid_t uid __aligned(8);
3408};
3409
3410static int unix_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
3411 struct unix_sock *unix_sk, uid_t uid)
3412{
3413 struct bpf_iter__unix ctx;
3414
3415 meta->seq_num--; /* skip SEQ_START_TOKEN */
3416 ctx.meta = meta;
3417 ctx.unix_sk = unix_sk;
3418 ctx.uid = uid;
3419 return bpf_iter_run_prog(prog, &ctx);
3420}
3421
3422static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk)
3423
3424{
3425 struct bpf_unix_iter_state *iter = seq->private;
3426 unsigned int expected = 1;
3427 struct sock *sk;
3428
3429 sock_hold(start_sk);
3430 iter->batch[iter->end_sk++] = start_sk;
3431
3432 for (sk = sk_next(start_sk); sk; sk = sk_next(sk)) {
3433 if (iter->end_sk < iter->max_sk) {
3434 sock_hold(sk);
3435 iter->batch[iter->end_sk++] = sk;
3436 }
3437
3438 expected++;
3439 }
3440
3441 spin_unlock(&seq_file_net(seq)->unx.table.locks[start_sk->sk_hash]);
3442
3443 return expected;
3444}
3445
3446static void bpf_iter_unix_put_batch(struct bpf_unix_iter_state *iter)
3447{
3448 while (iter->cur_sk < iter->end_sk)
3449 sock_put(iter->batch[iter->cur_sk++]);
3450}
3451
3452static int bpf_iter_unix_realloc_batch(struct bpf_unix_iter_state *iter,
3453 unsigned int new_batch_sz)
3454{
3455 struct sock **new_batch;
3456
3457 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3458 GFP_USER | __GFP_NOWARN);
3459 if (!new_batch)
3460 return -ENOMEM;
3461
3462 bpf_iter_unix_put_batch(iter);
3463 kvfree(iter->batch);
3464 iter->batch = new_batch;
3465 iter->max_sk = new_batch_sz;
3466
3467 return 0;
3468}
3469
3470static struct sock *bpf_iter_unix_batch(struct seq_file *seq,
3471 loff_t *pos)
3472{
3473 struct bpf_unix_iter_state *iter = seq->private;
3474 unsigned int expected;
3475 bool resized = false;
3476 struct sock *sk;
3477
3478 if (iter->st_bucket_done)
3479 *pos = set_bucket_offset(get_bucket(*pos) + 1, 1);
3480
3481again:
3482 /* Get a new batch */
3483 iter->cur_sk = 0;
3484 iter->end_sk = 0;
3485
3486 sk = unix_get_first(seq, pos);
3487 if (!sk)
3488 return NULL; /* Done */
3489
3490 expected = bpf_iter_unix_hold_batch(seq, sk);
3491
3492 if (iter->end_sk == expected) {
3493 iter->st_bucket_done = true;
3494 return sk;
3495 }
3496
3497 if (!resized && !bpf_iter_unix_realloc_batch(iter, expected * 3 / 2)) {
3498 resized = true;
3499 goto again;
3500 }
3501
3502 return sk;
3503}
3504
3505static void *bpf_iter_unix_seq_start(struct seq_file *seq, loff_t *pos)
3506{
3507 if (!*pos)
3508 return SEQ_START_TOKEN;
3509
3510 /* bpf iter does not support lseek, so it always
3511 * continue from where it was stop()-ped.
3512 */
3513 return bpf_iter_unix_batch(seq, pos);
3514}
3515
3516static void *bpf_iter_unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3517{
3518 struct bpf_unix_iter_state *iter = seq->private;
3519 struct sock *sk;
3520
3521 /* Whenever seq_next() is called, the iter->cur_sk is
3522 * done with seq_show(), so advance to the next sk in
3523 * the batch.
3524 */
3525 if (iter->cur_sk < iter->end_sk)
3526 sock_put(iter->batch[iter->cur_sk++]);
3527
3528 ++*pos;
3529
3530 if (iter->cur_sk < iter->end_sk)
3531 sk = iter->batch[iter->cur_sk];
3532 else
3533 sk = bpf_iter_unix_batch(seq, pos);
3534
3535 return sk;
3536}
3537
3538static int bpf_iter_unix_seq_show(struct seq_file *seq, void *v)
3539{
3540 struct bpf_iter_meta meta;
3541 struct bpf_prog *prog;
3542 struct sock *sk = v;
3543 uid_t uid;
3544 bool slow;
3545 int ret;
3546
3547 if (v == SEQ_START_TOKEN)
3548 return 0;
3549
3550 slow = lock_sock_fast(sk);
3551
3552 if (unlikely(sk_unhashed(sk))) {
3553 ret = SEQ_SKIP;
3554 goto unlock;
3555 }
3556
3557 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3558 meta.seq = seq;
3559 prog = bpf_iter_get_info(&meta, false);
3560 ret = unix_prog_seq_show(prog, &meta, v, uid);
3561unlock:
3562 unlock_sock_fast(sk, slow);
3563 return ret;
3564}
3565
3566static void bpf_iter_unix_seq_stop(struct seq_file *seq, void *v)
3567{
3568 struct bpf_unix_iter_state *iter = seq->private;
3569 struct bpf_iter_meta meta;
3570 struct bpf_prog *prog;
3571
3572 if (!v) {
3573 meta.seq = seq;
3574 prog = bpf_iter_get_info(&meta, true);
3575 if (prog)
3576 (void)unix_prog_seq_show(prog, &meta, v, 0);
3577 }
3578
3579 if (iter->cur_sk < iter->end_sk)
3580 bpf_iter_unix_put_batch(iter);
3581}
3582
3583static const struct seq_operations bpf_iter_unix_seq_ops = {
3584 .start = bpf_iter_unix_seq_start,
3585 .next = bpf_iter_unix_seq_next,
3586 .stop = bpf_iter_unix_seq_stop,
3587 .show = bpf_iter_unix_seq_show,
3588};
3589#endif
3590#endif
3591
3592static const struct net_proto_family unix_family_ops = {
3593 .family = PF_UNIX,
3594 .create = unix_create,
3595 .owner = THIS_MODULE,
3596};
3597
3598
3599static int __net_init unix_net_init(struct net *net)
3600{
3601 int i;
3602
3603 net->unx.sysctl_max_dgram_qlen = 10;
3604 if (unix_sysctl_register(net))
3605 goto out;
3606
3607#ifdef CONFIG_PROC_FS
3608 if (!proc_create_net("unix", 0, net->proc_net, &unix_seq_ops,
3609 sizeof(struct seq_net_private)))
3610 goto err_sysctl;
3611#endif
3612
3613 net->unx.table.locks = kvmalloc_array(UNIX_HASH_SIZE,
3614 sizeof(spinlock_t), GFP_KERNEL);
3615 if (!net->unx.table.locks)
3616 goto err_proc;
3617
3618 net->unx.table.buckets = kvmalloc_array(UNIX_HASH_SIZE,
3619 sizeof(struct hlist_head),
3620 GFP_KERNEL);
3621 if (!net->unx.table.buckets)
3622 goto free_locks;
3623
3624 for (i = 0; i < UNIX_HASH_SIZE; i++) {
3625 spin_lock_init(&net->unx.table.locks[i]);
3626 INIT_HLIST_HEAD(&net->unx.table.buckets[i]);
3627 }
3628
3629 return 0;
3630
3631free_locks:
3632 kvfree(net->unx.table.locks);
3633err_proc:
3634#ifdef CONFIG_PROC_FS
3635 remove_proc_entry("unix", net->proc_net);
3636err_sysctl:
3637#endif
3638 unix_sysctl_unregister(net);
3639out:
3640 return -ENOMEM;
3641}
3642
3643static void __net_exit unix_net_exit(struct net *net)
3644{
3645 kvfree(net->unx.table.buckets);
3646 kvfree(net->unx.table.locks);
3647 unix_sysctl_unregister(net);
3648 remove_proc_entry("unix", net->proc_net);
3649}
3650
3651static struct pernet_operations unix_net_ops = {
3652 .init = unix_net_init,
3653 .exit = unix_net_exit,
3654};
3655
3656#if IS_BUILTIN(CONFIG_UNIX) && defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3657DEFINE_BPF_ITER_FUNC(unix, struct bpf_iter_meta *meta,
3658 struct unix_sock *unix_sk, uid_t uid)
3659
3660#define INIT_BATCH_SZ 16
3661
3662static int bpf_iter_init_unix(void *priv_data, struct bpf_iter_aux_info *aux)
3663{
3664 struct bpf_unix_iter_state *iter = priv_data;
3665 int err;
3666
3667 err = bpf_iter_init_seq_net(priv_data, aux);
3668 if (err)
3669 return err;
3670
3671 err = bpf_iter_unix_realloc_batch(iter, INIT_BATCH_SZ);
3672 if (err) {
3673 bpf_iter_fini_seq_net(priv_data);
3674 return err;
3675 }
3676
3677 return 0;
3678}
3679
3680static void bpf_iter_fini_unix(void *priv_data)
3681{
3682 struct bpf_unix_iter_state *iter = priv_data;
3683
3684 bpf_iter_fini_seq_net(priv_data);
3685 kvfree(iter->batch);
3686}
3687
3688static const struct bpf_iter_seq_info unix_seq_info = {
3689 .seq_ops = &bpf_iter_unix_seq_ops,
3690 .init_seq_private = bpf_iter_init_unix,
3691 .fini_seq_private = bpf_iter_fini_unix,
3692 .seq_priv_size = sizeof(struct bpf_unix_iter_state),
3693};
3694
3695static const struct bpf_func_proto *
3696bpf_iter_unix_get_func_proto(enum bpf_func_id func_id,
3697 const struct bpf_prog *prog)
3698{
3699 switch (func_id) {
3700 case BPF_FUNC_setsockopt:
3701 return &bpf_sk_setsockopt_proto;
3702 case BPF_FUNC_getsockopt:
3703 return &bpf_sk_getsockopt_proto;
3704 default:
3705 return NULL;
3706 }
3707}
3708
3709static struct bpf_iter_reg unix_reg_info = {
3710 .target = "unix",
3711 .ctx_arg_info_size = 1,
3712 .ctx_arg_info = {
3713 { offsetof(struct bpf_iter__unix, unix_sk),
3714 PTR_TO_BTF_ID_OR_NULL },
3715 },
3716 .get_func_proto = bpf_iter_unix_get_func_proto,
3717 .seq_info = &unix_seq_info,
3718};
3719
3720static void __init bpf_iter_register(void)
3721{
3722 unix_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UNIX];
3723 if (bpf_iter_reg_target(&unix_reg_info))
3724 pr_warn("Warning: could not register bpf iterator unix\n");
3725}
3726#endif
3727
3728static int __init af_unix_init(void)
3729{
3730 int i, rc = -1;
3731
3732 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb));
3733
3734 for (i = 0; i < UNIX_HASH_SIZE / 2; i++) {
3735 spin_lock_init(&bsd_socket_locks[i]);
3736 INIT_HLIST_HEAD(&bsd_socket_buckets[i]);
3737 }
3738
3739 rc = proto_register(&unix_dgram_proto, 1);
3740 if (rc != 0) {
3741 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
3742 goto out;
3743 }
3744
3745 rc = proto_register(&unix_stream_proto, 1);
3746 if (rc != 0) {
3747 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
3748 proto_unregister(&unix_dgram_proto);
3749 goto out;
3750 }
3751
3752 sock_register(&unix_family_ops);
3753 register_pernet_subsys(&unix_net_ops);
3754 unix_bpf_build_proto();
3755
3756#if IS_BUILTIN(CONFIG_UNIX) && defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3757 bpf_iter_register();
3758#endif
3759
3760out:
3761 return rc;
3762}
3763
3764static void __exit af_unix_exit(void)
3765{
3766 sock_unregister(PF_UNIX);
3767 proto_unregister(&unix_dgram_proto);
3768 proto_unregister(&unix_stream_proto);
3769 unregister_pernet_subsys(&unix_net_ops);
3770}
3771
3772/* Earlier than device_initcall() so that other drivers invoking
3773 request_module() don't end up in a loop when modprobe tries
3774 to use a UNIX socket. But later than subsys_initcall() because
3775 we depend on stuff initialised there */
3776fs_initcall(af_unix_init);
3777module_exit(af_unix_exit);
3778
3779MODULE_LICENSE("GPL");
3780MODULE_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);