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