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/splice.h>
116#include <linux/freezer.h>
117#include <linux/file.h>
118#include <linux/btf_ids.h>
119#include <linux/bpf-cgroup.h>
120
121#include "scm.h"
122
123static atomic_long_t unix_nr_socks;
124static struct hlist_head bsd_socket_buckets[UNIX_HASH_SIZE / 2];
125static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2];
126
127/* SMP locking strategy:
128 * hash table is protected with spinlock.
129 * each socket state is protected by separate spinlock.
130 */
131
132static unsigned int unix_unbound_hash(struct sock *sk)
133{
134 unsigned long hash = (unsigned long)sk;
135
136 hash ^= hash >> 16;
137 hash ^= hash >> 8;
138 hash ^= sk->sk_type;
139
140 return hash & UNIX_HASH_MOD;
141}
142
143static unsigned int unix_bsd_hash(struct inode *i)
144{
145 return i->i_ino & UNIX_HASH_MOD;
146}
147
148static unsigned int unix_abstract_hash(struct sockaddr_un *sunaddr,
149 int addr_len, int type)
150{
151 __wsum csum = csum_partial(sunaddr, addr_len, 0);
152 unsigned int hash;
153
154 hash = (__force unsigned int)csum_fold(csum);
155 hash ^= hash >> 8;
156 hash ^= type;
157
158 return UNIX_HASH_MOD + 1 + (hash & UNIX_HASH_MOD);
159}
160
161static void unix_table_double_lock(struct net *net,
162 unsigned int hash1, unsigned int hash2)
163{
164 if (hash1 == hash2) {
165 spin_lock(&net->unx.table.locks[hash1]);
166 return;
167 }
168
169 if (hash1 > hash2)
170 swap(hash1, hash2);
171
172 spin_lock(&net->unx.table.locks[hash1]);
173 spin_lock_nested(&net->unx.table.locks[hash2], SINGLE_DEPTH_NESTING);
174}
175
176static void unix_table_double_unlock(struct net *net,
177 unsigned int hash1, unsigned int hash2)
178{
179 if (hash1 == hash2) {
180 spin_unlock(&net->unx.table.locks[hash1]);
181 return;
182 }
183
184 spin_unlock(&net->unx.table.locks[hash1]);
185 spin_unlock(&net->unx.table.locks[hash2]);
186}
187
188#ifdef CONFIG_SECURITY_NETWORK
189static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
190{
191 UNIXCB(skb).secid = scm->secid;
192}
193
194static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
195{
196 scm->secid = UNIXCB(skb).secid;
197}
198
199static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
200{
201 return (scm->secid == UNIXCB(skb).secid);
202}
203#else
204static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
205{ }
206
207static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
208{ }
209
210static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
211{
212 return true;
213}
214#endif /* CONFIG_SECURITY_NETWORK */
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 int unix_mkname_bsd(struct sockaddr_un *sunaddr, int addr_len)
292{
293 struct sockaddr_storage *addr = (struct sockaddr_storage *)sunaddr;
294 short offset = offsetof(struct sockaddr_storage, __data);
295
296 BUILD_BUG_ON(offset != offsetof(struct sockaddr_un, sun_path));
297
298 /* This may look like an off by one error but it is a bit more
299 * subtle. 108 is the longest valid AF_UNIX path for a binding.
300 * sun_path[108] doesn't as such exist. However in kernel space
301 * we are guaranteed that it is a valid memory location in our
302 * kernel address buffer because syscall functions always pass
303 * a pointer of struct sockaddr_storage which has a bigger buffer
304 * than 108. Also, we must terminate sun_path for strlen() in
305 * getname_kernel().
306 */
307 addr->__data[addr_len - offset] = 0;
308
309 /* Don't pass sunaddr->sun_path to strlen(). Otherwise, 108 will
310 * cause panic if CONFIG_FORTIFY_SOURCE=y. Let __fortify_strlen()
311 * know the actual buffer.
312 */
313 return strlen(addr->__data) + offset + 1;
314}
315
316static void __unix_remove_socket(struct sock *sk)
317{
318 sk_del_node_init(sk);
319}
320
321static void __unix_insert_socket(struct net *net, struct sock *sk)
322{
323 DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk));
324 sk_add_node(sk, &net->unx.table.buckets[sk->sk_hash]);
325}
326
327static void __unix_set_addr_hash(struct net *net, struct sock *sk,
328 struct unix_address *addr, unsigned int hash)
329{
330 __unix_remove_socket(sk);
331 smp_store_release(&unix_sk(sk)->addr, addr);
332
333 sk->sk_hash = hash;
334 __unix_insert_socket(net, sk);
335}
336
337static void unix_remove_socket(struct net *net, struct sock *sk)
338{
339 spin_lock(&net->unx.table.locks[sk->sk_hash]);
340 __unix_remove_socket(sk);
341 spin_unlock(&net->unx.table.locks[sk->sk_hash]);
342}
343
344static void unix_insert_unbound_socket(struct net *net, struct sock *sk)
345{
346 spin_lock(&net->unx.table.locks[sk->sk_hash]);
347 __unix_insert_socket(net, sk);
348 spin_unlock(&net->unx.table.locks[sk->sk_hash]);
349}
350
351static void unix_insert_bsd_socket(struct sock *sk)
352{
353 spin_lock(&bsd_socket_locks[sk->sk_hash]);
354 sk_add_bind_node(sk, &bsd_socket_buckets[sk->sk_hash]);
355 spin_unlock(&bsd_socket_locks[sk->sk_hash]);
356}
357
358static void unix_remove_bsd_socket(struct sock *sk)
359{
360 if (!hlist_unhashed(&sk->sk_bind_node)) {
361 spin_lock(&bsd_socket_locks[sk->sk_hash]);
362 __sk_del_bind_node(sk);
363 spin_unlock(&bsd_socket_locks[sk->sk_hash]);
364
365 sk_node_init(&sk->sk_bind_node);
366 }
367}
368
369static struct sock *__unix_find_socket_byname(struct net *net,
370 struct sockaddr_un *sunname,
371 int len, unsigned int hash)
372{
373 struct sock *s;
374
375 sk_for_each(s, &net->unx.table.buckets[hash]) {
376 struct unix_sock *u = unix_sk(s);
377
378 if (u->addr->len == len &&
379 !memcmp(u->addr->name, sunname, len))
380 return s;
381 }
382 return NULL;
383}
384
385static inline struct sock *unix_find_socket_byname(struct net *net,
386 struct sockaddr_un *sunname,
387 int len, unsigned int hash)
388{
389 struct sock *s;
390
391 spin_lock(&net->unx.table.locks[hash]);
392 s = __unix_find_socket_byname(net, sunname, len, hash);
393 if (s)
394 sock_hold(s);
395 spin_unlock(&net->unx.table.locks[hash]);
396 return s;
397}
398
399static struct sock *unix_find_socket_byinode(struct inode *i)
400{
401 unsigned int hash = unix_bsd_hash(i);
402 struct sock *s;
403
404 spin_lock(&bsd_socket_locks[hash]);
405 sk_for_each_bound(s, &bsd_socket_buckets[hash]) {
406 struct dentry *dentry = unix_sk(s)->path.dentry;
407
408 if (dentry && d_backing_inode(dentry) == i) {
409 sock_hold(s);
410 spin_unlock(&bsd_socket_locks[hash]);
411 return s;
412 }
413 }
414 spin_unlock(&bsd_socket_locks[hash]);
415 return NULL;
416}
417
418/* Support code for asymmetrically connected dgram sockets
419 *
420 * If a datagram socket is connected to a socket not itself connected
421 * to the first socket (eg, /dev/log), clients may only enqueue more
422 * messages if the present receive queue of the server socket is not
423 * "too large". This means there's a second writeability condition
424 * poll and sendmsg need to test. The dgram recv code will do a wake
425 * up on the peer_wait wait queue of a socket upon reception of a
426 * datagram which needs to be propagated to sleeping would-be writers
427 * since these might not have sent anything so far. This can't be
428 * accomplished via poll_wait because the lifetime of the server
429 * socket might be less than that of its clients if these break their
430 * association with it or if the server socket is closed while clients
431 * are still connected to it and there's no way to inform "a polling
432 * implementation" that it should let go of a certain wait queue
433 *
434 * In order to propagate a wake up, a wait_queue_entry_t of the client
435 * socket is enqueued on the peer_wait queue of the server socket
436 * whose wake function does a wake_up on the ordinary client socket
437 * wait queue. This connection is established whenever a write (or
438 * poll for write) hit the flow control condition and broken when the
439 * association to the server socket is dissolved or after a wake up
440 * was relayed.
441 */
442
443static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
444 void *key)
445{
446 struct unix_sock *u;
447 wait_queue_head_t *u_sleep;
448
449 u = container_of(q, struct unix_sock, peer_wake);
450
451 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
452 q);
453 u->peer_wake.private = NULL;
454
455 /* relaying can only happen while the wq still exists */
456 u_sleep = sk_sleep(&u->sk);
457 if (u_sleep)
458 wake_up_interruptible_poll(u_sleep, key_to_poll(key));
459
460 return 0;
461}
462
463static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
464{
465 struct unix_sock *u, *u_other;
466 int rc;
467
468 u = unix_sk(sk);
469 u_other = unix_sk(other);
470 rc = 0;
471 spin_lock(&u_other->peer_wait.lock);
472
473 if (!u->peer_wake.private) {
474 u->peer_wake.private = other;
475 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
476
477 rc = 1;
478 }
479
480 spin_unlock(&u_other->peer_wait.lock);
481 return rc;
482}
483
484static void unix_dgram_peer_wake_disconnect(struct sock *sk,
485 struct sock *other)
486{
487 struct unix_sock *u, *u_other;
488
489 u = unix_sk(sk);
490 u_other = unix_sk(other);
491 spin_lock(&u_other->peer_wait.lock);
492
493 if (u->peer_wake.private == other) {
494 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
495 u->peer_wake.private = NULL;
496 }
497
498 spin_unlock(&u_other->peer_wait.lock);
499}
500
501static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
502 struct sock *other)
503{
504 unix_dgram_peer_wake_disconnect(sk, other);
505 wake_up_interruptible_poll(sk_sleep(sk),
506 EPOLLOUT |
507 EPOLLWRNORM |
508 EPOLLWRBAND);
509}
510
511/* preconditions:
512 * - unix_peer(sk) == other
513 * - association is stable
514 */
515static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
516{
517 int connected;
518
519 connected = unix_dgram_peer_wake_connect(sk, other);
520
521 /* If other is SOCK_DEAD, we want to make sure we signal
522 * POLLOUT, such that a subsequent write() can get a
523 * -ECONNREFUSED. Otherwise, if we haven't queued any skbs
524 * to other and its full, we will hang waiting for POLLOUT.
525 */
526 if (unix_recvq_full_lockless(other) && !sock_flag(other, SOCK_DEAD))
527 return 1;
528
529 if (connected)
530 unix_dgram_peer_wake_disconnect(sk, other);
531
532 return 0;
533}
534
535static int unix_writable(const struct sock *sk)
536{
537 return sk->sk_state != TCP_LISTEN &&
538 (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
539}
540
541static void unix_write_space(struct sock *sk)
542{
543 struct socket_wq *wq;
544
545 rcu_read_lock();
546 if (unix_writable(sk)) {
547 wq = rcu_dereference(sk->sk_wq);
548 if (skwq_has_sleeper(wq))
549 wake_up_interruptible_sync_poll(&wq->wait,
550 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
551 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
552 }
553 rcu_read_unlock();
554}
555
556/* When dgram socket disconnects (or changes its peer), we clear its receive
557 * queue of packets arrived from previous peer. First, it allows to do
558 * flow control based only on wmem_alloc; second, sk connected to peer
559 * may receive messages only from that peer. */
560static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
561{
562 if (!skb_queue_empty(&sk->sk_receive_queue)) {
563 skb_queue_purge(&sk->sk_receive_queue);
564 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
565
566 /* If one link of bidirectional dgram pipe is disconnected,
567 * we signal error. Messages are lost. Do not make this,
568 * when peer was not connected to us.
569 */
570 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
571 WRITE_ONCE(other->sk_err, ECONNRESET);
572 sk_error_report(other);
573 }
574 }
575 other->sk_state = TCP_CLOSE;
576}
577
578static void unix_sock_destructor(struct sock *sk)
579{
580 struct unix_sock *u = unix_sk(sk);
581
582 skb_queue_purge(&sk->sk_receive_queue);
583
584 DEBUG_NET_WARN_ON_ONCE(refcount_read(&sk->sk_wmem_alloc));
585 DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk));
586 DEBUG_NET_WARN_ON_ONCE(sk->sk_socket);
587 if (!sock_flag(sk, SOCK_DEAD)) {
588 pr_info("Attempt to release alive unix socket: %p\n", sk);
589 return;
590 }
591
592 if (u->addr)
593 unix_release_addr(u->addr);
594
595 atomic_long_dec(&unix_nr_socks);
596 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
597#ifdef UNIX_REFCNT_DEBUG
598 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
599 atomic_long_read(&unix_nr_socks));
600#endif
601}
602
603static void unix_release_sock(struct sock *sk, int embrion)
604{
605 struct unix_sock *u = unix_sk(sk);
606 struct sock *skpair;
607 struct sk_buff *skb;
608 struct path path;
609 int state;
610
611 unix_remove_socket(sock_net(sk), sk);
612 unix_remove_bsd_socket(sk);
613
614 /* Clear state */
615 unix_state_lock(sk);
616 sock_orphan(sk);
617 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
618 path = u->path;
619 u->path.dentry = NULL;
620 u->path.mnt = NULL;
621 state = sk->sk_state;
622 sk->sk_state = TCP_CLOSE;
623
624 skpair = unix_peer(sk);
625 unix_peer(sk) = NULL;
626
627 unix_state_unlock(sk);
628
629#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
630 if (u->oob_skb) {
631 kfree_skb(u->oob_skb);
632 u->oob_skb = NULL;
633 }
634#endif
635
636 wake_up_interruptible_all(&u->peer_wait);
637
638 if (skpair != NULL) {
639 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
640 unix_state_lock(skpair);
641 /* No more writes */
642 WRITE_ONCE(skpair->sk_shutdown, SHUTDOWN_MASK);
643 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
644 WRITE_ONCE(skpair->sk_err, ECONNRESET);
645 unix_state_unlock(skpair);
646 skpair->sk_state_change(skpair);
647 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
648 }
649
650 unix_dgram_peer_wake_disconnect(sk, skpair);
651 sock_put(skpair); /* It may now die */
652 }
653
654 /* Try to flush out this socket. Throw out buffers at least */
655
656 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
657 if (state == TCP_LISTEN)
658 unix_release_sock(skb->sk, 1);
659 /* passed fds are erased in the kfree_skb hook */
660 UNIXCB(skb).consumed = skb->len;
661 kfree_skb(skb);
662 }
663
664 if (path.dentry)
665 path_put(&path);
666
667 sock_put(sk);
668
669 /* ---- Socket is dead now and most probably destroyed ---- */
670
671 /*
672 * Fixme: BSD difference: In BSD all sockets connected to us get
673 * ECONNRESET and we die on the spot. In Linux we behave
674 * like files and pipes do and wait for the last
675 * dereference.
676 *
677 * Can't we simply set sock->err?
678 *
679 * What the above comment does talk about? --ANK(980817)
680 */
681
682 if (READ_ONCE(unix_tot_inflight))
683 unix_gc(); /* Garbage collect fds */
684}
685
686static void init_peercred(struct sock *sk)
687{
688 const struct cred *old_cred;
689 struct pid *old_pid;
690
691 spin_lock(&sk->sk_peer_lock);
692 old_pid = sk->sk_peer_pid;
693 old_cred = sk->sk_peer_cred;
694 sk->sk_peer_pid = get_pid(task_tgid(current));
695 sk->sk_peer_cred = get_current_cred();
696 spin_unlock(&sk->sk_peer_lock);
697
698 put_pid(old_pid);
699 put_cred(old_cred);
700}
701
702static void copy_peercred(struct sock *sk, struct sock *peersk)
703{
704 const struct cred *old_cred;
705 struct pid *old_pid;
706
707 if (sk < peersk) {
708 spin_lock(&sk->sk_peer_lock);
709 spin_lock_nested(&peersk->sk_peer_lock, SINGLE_DEPTH_NESTING);
710 } else {
711 spin_lock(&peersk->sk_peer_lock);
712 spin_lock_nested(&sk->sk_peer_lock, SINGLE_DEPTH_NESTING);
713 }
714 old_pid = sk->sk_peer_pid;
715 old_cred = sk->sk_peer_cred;
716 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
717 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
718
719 spin_unlock(&sk->sk_peer_lock);
720 spin_unlock(&peersk->sk_peer_lock);
721
722 put_pid(old_pid);
723 put_cred(old_cred);
724}
725
726static int unix_listen(struct socket *sock, int backlog)
727{
728 int err;
729 struct sock *sk = sock->sk;
730 struct unix_sock *u = unix_sk(sk);
731
732 err = -EOPNOTSUPP;
733 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
734 goto out; /* Only stream/seqpacket sockets accept */
735 err = -EINVAL;
736 if (!u->addr)
737 goto out; /* No listens on an unbound socket */
738 unix_state_lock(sk);
739 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
740 goto out_unlock;
741 if (backlog > sk->sk_max_ack_backlog)
742 wake_up_interruptible_all(&u->peer_wait);
743 sk->sk_max_ack_backlog = backlog;
744 sk->sk_state = TCP_LISTEN;
745 /* set credentials so connect can copy them */
746 init_peercred(sk);
747 err = 0;
748
749out_unlock:
750 unix_state_unlock(sk);
751out:
752 return err;
753}
754
755static int unix_release(struct socket *);
756static int unix_bind(struct socket *, struct sockaddr *, int);
757static int unix_stream_connect(struct socket *, struct sockaddr *,
758 int addr_len, int flags);
759static int unix_socketpair(struct socket *, struct socket *);
760static int unix_accept(struct socket *, struct socket *, int, bool);
761static int unix_getname(struct socket *, struct sockaddr *, int);
762static __poll_t unix_poll(struct file *, struct socket *, poll_table *);
763static __poll_t unix_dgram_poll(struct file *, struct socket *,
764 poll_table *);
765static int unix_ioctl(struct socket *, unsigned int, unsigned long);
766#ifdef CONFIG_COMPAT
767static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
768#endif
769static int unix_shutdown(struct socket *, int);
770static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
771static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
772static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
773 struct pipe_inode_info *, size_t size,
774 unsigned int flags);
775static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
776static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
777static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
778static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
779static int unix_dgram_connect(struct socket *, struct sockaddr *,
780 int, int);
781static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
782static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
783 int);
784
785#ifdef CONFIG_PROC_FS
786static int unix_count_nr_fds(struct sock *sk)
787{
788 struct sk_buff *skb;
789 struct unix_sock *u;
790 int nr_fds = 0;
791
792 spin_lock(&sk->sk_receive_queue.lock);
793 skb = skb_peek(&sk->sk_receive_queue);
794 while (skb) {
795 u = unix_sk(skb->sk);
796 nr_fds += atomic_read(&u->scm_stat.nr_fds);
797 skb = skb_peek_next(skb, &sk->sk_receive_queue);
798 }
799 spin_unlock(&sk->sk_receive_queue.lock);
800
801 return nr_fds;
802}
803
804static void unix_show_fdinfo(struct seq_file *m, struct socket *sock)
805{
806 struct sock *sk = sock->sk;
807 unsigned char s_state;
808 struct unix_sock *u;
809 int nr_fds = 0;
810
811 if (sk) {
812 s_state = READ_ONCE(sk->sk_state);
813 u = unix_sk(sk);
814
815 /* SOCK_STREAM and SOCK_SEQPACKET sockets never change their
816 * sk_state after switching to TCP_ESTABLISHED or TCP_LISTEN.
817 * SOCK_DGRAM is ordinary. So, no lock is needed.
818 */
819 if (sock->type == SOCK_DGRAM || s_state == TCP_ESTABLISHED)
820 nr_fds = atomic_read(&u->scm_stat.nr_fds);
821 else if (s_state == TCP_LISTEN)
822 nr_fds = unix_count_nr_fds(sk);
823
824 seq_printf(m, "scm_fds: %u\n", nr_fds);
825 }
826}
827#else
828#define unix_show_fdinfo NULL
829#endif
830
831static const struct proto_ops unix_stream_ops = {
832 .family = PF_UNIX,
833 .owner = THIS_MODULE,
834 .release = unix_release,
835 .bind = unix_bind,
836 .connect = unix_stream_connect,
837 .socketpair = unix_socketpair,
838 .accept = unix_accept,
839 .getname = unix_getname,
840 .poll = unix_poll,
841 .ioctl = unix_ioctl,
842#ifdef CONFIG_COMPAT
843 .compat_ioctl = unix_compat_ioctl,
844#endif
845 .listen = unix_listen,
846 .shutdown = unix_shutdown,
847 .sendmsg = unix_stream_sendmsg,
848 .recvmsg = unix_stream_recvmsg,
849 .read_skb = unix_stream_read_skb,
850 .mmap = sock_no_mmap,
851 .splice_read = unix_stream_splice_read,
852 .set_peek_off = sk_set_peek_off,
853 .show_fdinfo = unix_show_fdinfo,
854};
855
856static const struct proto_ops unix_dgram_ops = {
857 .family = PF_UNIX,
858 .owner = THIS_MODULE,
859 .release = unix_release,
860 .bind = unix_bind,
861 .connect = unix_dgram_connect,
862 .socketpair = unix_socketpair,
863 .accept = sock_no_accept,
864 .getname = unix_getname,
865 .poll = unix_dgram_poll,
866 .ioctl = unix_ioctl,
867#ifdef CONFIG_COMPAT
868 .compat_ioctl = unix_compat_ioctl,
869#endif
870 .listen = sock_no_listen,
871 .shutdown = unix_shutdown,
872 .sendmsg = unix_dgram_sendmsg,
873 .read_skb = unix_read_skb,
874 .recvmsg = unix_dgram_recvmsg,
875 .mmap = sock_no_mmap,
876 .set_peek_off = sk_set_peek_off,
877 .show_fdinfo = unix_show_fdinfo,
878};
879
880static const struct proto_ops unix_seqpacket_ops = {
881 .family = PF_UNIX,
882 .owner = THIS_MODULE,
883 .release = unix_release,
884 .bind = unix_bind,
885 .connect = unix_stream_connect,
886 .socketpair = unix_socketpair,
887 .accept = unix_accept,
888 .getname = unix_getname,
889 .poll = unix_dgram_poll,
890 .ioctl = unix_ioctl,
891#ifdef CONFIG_COMPAT
892 .compat_ioctl = unix_compat_ioctl,
893#endif
894 .listen = unix_listen,
895 .shutdown = unix_shutdown,
896 .sendmsg = unix_seqpacket_sendmsg,
897 .recvmsg = unix_seqpacket_recvmsg,
898 .mmap = sock_no_mmap,
899 .set_peek_off = sk_set_peek_off,
900 .show_fdinfo = unix_show_fdinfo,
901};
902
903static void unix_close(struct sock *sk, long timeout)
904{
905 /* Nothing to do here, unix socket does not need a ->close().
906 * This is merely for sockmap.
907 */
908}
909
910static void unix_unhash(struct sock *sk)
911{
912 /* Nothing to do here, unix socket does not need a ->unhash().
913 * This is merely for sockmap.
914 */
915}
916
917static bool unix_bpf_bypass_getsockopt(int level, int optname)
918{
919 if (level == SOL_SOCKET) {
920 switch (optname) {
921 case SO_PEERPIDFD:
922 return true;
923 default:
924 return false;
925 }
926 }
927
928 return false;
929}
930
931struct proto unix_dgram_proto = {
932 .name = "UNIX",
933 .owner = THIS_MODULE,
934 .obj_size = sizeof(struct unix_sock),
935 .close = unix_close,
936 .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt,
937#ifdef CONFIG_BPF_SYSCALL
938 .psock_update_sk_prot = unix_dgram_bpf_update_proto,
939#endif
940};
941
942struct proto unix_stream_proto = {
943 .name = "UNIX-STREAM",
944 .owner = THIS_MODULE,
945 .obj_size = sizeof(struct unix_sock),
946 .close = unix_close,
947 .unhash = unix_unhash,
948 .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt,
949#ifdef CONFIG_BPF_SYSCALL
950 .psock_update_sk_prot = unix_stream_bpf_update_proto,
951#endif
952};
953
954static struct sock *unix_create1(struct net *net, struct socket *sock, int kern, int type)
955{
956 struct unix_sock *u;
957 struct sock *sk;
958 int err;
959
960 atomic_long_inc(&unix_nr_socks);
961 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) {
962 err = -ENFILE;
963 goto err;
964 }
965
966 if (type == SOCK_STREAM)
967 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_stream_proto, kern);
968 else /*dgram and seqpacket */
969 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_dgram_proto, kern);
970
971 if (!sk) {
972 err = -ENOMEM;
973 goto err;
974 }
975
976 sock_init_data(sock, sk);
977
978 sk->sk_hash = unix_unbound_hash(sk);
979 sk->sk_allocation = GFP_KERNEL_ACCOUNT;
980 sk->sk_write_space = unix_write_space;
981 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
982 sk->sk_destruct = unix_sock_destructor;
983 u = unix_sk(sk);
984 u->path.dentry = NULL;
985 u->path.mnt = NULL;
986 spin_lock_init(&u->lock);
987 atomic_long_set(&u->inflight, 0);
988 INIT_LIST_HEAD(&u->link);
989 mutex_init(&u->iolock); /* single task reading lock */
990 mutex_init(&u->bindlock); /* single task binding lock */
991 init_waitqueue_head(&u->peer_wait);
992 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
993 memset(&u->scm_stat, 0, sizeof(struct scm_stat));
994 unix_insert_unbound_socket(net, sk);
995
996 sock_prot_inuse_add(net, sk->sk_prot, 1);
997
998 return sk;
999
1000err:
1001 atomic_long_dec(&unix_nr_socks);
1002 return ERR_PTR(err);
1003}
1004
1005static int unix_create(struct net *net, struct socket *sock, int protocol,
1006 int kern)
1007{
1008 struct sock *sk;
1009
1010 if (protocol && protocol != PF_UNIX)
1011 return -EPROTONOSUPPORT;
1012
1013 sock->state = SS_UNCONNECTED;
1014
1015 switch (sock->type) {
1016 case SOCK_STREAM:
1017 sock->ops = &unix_stream_ops;
1018 break;
1019 /*
1020 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
1021 * nothing uses it.
1022 */
1023 case SOCK_RAW:
1024 sock->type = SOCK_DGRAM;
1025 fallthrough;
1026 case SOCK_DGRAM:
1027 sock->ops = &unix_dgram_ops;
1028 break;
1029 case SOCK_SEQPACKET:
1030 sock->ops = &unix_seqpacket_ops;
1031 break;
1032 default:
1033 return -ESOCKTNOSUPPORT;
1034 }
1035
1036 sk = unix_create1(net, sock, kern, sock->type);
1037 if (IS_ERR(sk))
1038 return PTR_ERR(sk);
1039
1040 return 0;
1041}
1042
1043static int unix_release(struct socket *sock)
1044{
1045 struct sock *sk = sock->sk;
1046
1047 if (!sk)
1048 return 0;
1049
1050 sk->sk_prot->close(sk, 0);
1051 unix_release_sock(sk, 0);
1052 sock->sk = NULL;
1053
1054 return 0;
1055}
1056
1057static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len,
1058 int type)
1059{
1060 struct inode *inode;
1061 struct path path;
1062 struct sock *sk;
1063 int err;
1064
1065 unix_mkname_bsd(sunaddr, addr_len);
1066 err = kern_path(sunaddr->sun_path, LOOKUP_FOLLOW, &path);
1067 if (err)
1068 goto fail;
1069
1070 err = path_permission(&path, MAY_WRITE);
1071 if (err)
1072 goto path_put;
1073
1074 err = -ECONNREFUSED;
1075 inode = d_backing_inode(path.dentry);
1076 if (!S_ISSOCK(inode->i_mode))
1077 goto path_put;
1078
1079 sk = unix_find_socket_byinode(inode);
1080 if (!sk)
1081 goto path_put;
1082
1083 err = -EPROTOTYPE;
1084 if (sk->sk_type == type)
1085 touch_atime(&path);
1086 else
1087 goto sock_put;
1088
1089 path_put(&path);
1090
1091 return sk;
1092
1093sock_put:
1094 sock_put(sk);
1095path_put:
1096 path_put(&path);
1097fail:
1098 return ERR_PTR(err);
1099}
1100
1101static struct sock *unix_find_abstract(struct net *net,
1102 struct sockaddr_un *sunaddr,
1103 int addr_len, int type)
1104{
1105 unsigned int hash = unix_abstract_hash(sunaddr, addr_len, type);
1106 struct dentry *dentry;
1107 struct sock *sk;
1108
1109 sk = unix_find_socket_byname(net, sunaddr, addr_len, hash);
1110 if (!sk)
1111 return ERR_PTR(-ECONNREFUSED);
1112
1113 dentry = unix_sk(sk)->path.dentry;
1114 if (dentry)
1115 touch_atime(&unix_sk(sk)->path);
1116
1117 return sk;
1118}
1119
1120static struct sock *unix_find_other(struct net *net,
1121 struct sockaddr_un *sunaddr,
1122 int addr_len, int type)
1123{
1124 struct sock *sk;
1125
1126 if (sunaddr->sun_path[0])
1127 sk = unix_find_bsd(sunaddr, addr_len, type);
1128 else
1129 sk = unix_find_abstract(net, sunaddr, addr_len, type);
1130
1131 return sk;
1132}
1133
1134static int unix_autobind(struct sock *sk)
1135{
1136 unsigned int new_hash, old_hash = sk->sk_hash;
1137 struct unix_sock *u = unix_sk(sk);
1138 struct net *net = sock_net(sk);
1139 struct unix_address *addr;
1140 u32 lastnum, ordernum;
1141 int err;
1142
1143 err = mutex_lock_interruptible(&u->bindlock);
1144 if (err)
1145 return err;
1146
1147 if (u->addr)
1148 goto out;
1149
1150 err = -ENOMEM;
1151 addr = kzalloc(sizeof(*addr) +
1152 offsetof(struct sockaddr_un, sun_path) + 16, GFP_KERNEL);
1153 if (!addr)
1154 goto out;
1155
1156 addr->len = offsetof(struct sockaddr_un, sun_path) + 6;
1157 addr->name->sun_family = AF_UNIX;
1158 refcount_set(&addr->refcnt, 1);
1159
1160 ordernum = get_random_u32();
1161 lastnum = ordernum & 0xFFFFF;
1162retry:
1163 ordernum = (ordernum + 1) & 0xFFFFF;
1164 sprintf(addr->name->sun_path + 1, "%05x", ordernum);
1165
1166 new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);
1167 unix_table_double_lock(net, old_hash, new_hash);
1168
1169 if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) {
1170 unix_table_double_unlock(net, old_hash, new_hash);
1171
1172 /* __unix_find_socket_byname() may take long time if many names
1173 * are already in use.
1174 */
1175 cond_resched();
1176
1177 if (ordernum == lastnum) {
1178 /* Give up if all names seems to be in use. */
1179 err = -ENOSPC;
1180 unix_release_addr(addr);
1181 goto out;
1182 }
1183
1184 goto retry;
1185 }
1186
1187 __unix_set_addr_hash(net, sk, addr, new_hash);
1188 unix_table_double_unlock(net, old_hash, new_hash);
1189 err = 0;
1190
1191out: mutex_unlock(&u->bindlock);
1192 return err;
1193}
1194
1195static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr,
1196 int addr_len)
1197{
1198 umode_t mode = S_IFSOCK |
1199 (SOCK_INODE(sk->sk_socket)->i_mode & ~current_umask());
1200 unsigned int new_hash, old_hash = sk->sk_hash;
1201 struct unix_sock *u = unix_sk(sk);
1202 struct net *net = sock_net(sk);
1203 struct mnt_idmap *idmap;
1204 struct unix_address *addr;
1205 struct dentry *dentry;
1206 struct path parent;
1207 int err;
1208
1209 addr_len = unix_mkname_bsd(sunaddr, addr_len);
1210 addr = unix_create_addr(sunaddr, addr_len);
1211 if (!addr)
1212 return -ENOMEM;
1213
1214 /*
1215 * Get the parent directory, calculate the hash for last
1216 * component.
1217 */
1218 dentry = kern_path_create(AT_FDCWD, addr->name->sun_path, &parent, 0);
1219 if (IS_ERR(dentry)) {
1220 err = PTR_ERR(dentry);
1221 goto out;
1222 }
1223
1224 /*
1225 * All right, let's create it.
1226 */
1227 idmap = mnt_idmap(parent.mnt);
1228 err = security_path_mknod(&parent, dentry, mode, 0);
1229 if (!err)
1230 err = vfs_mknod(idmap, d_inode(parent.dentry), dentry, mode, 0);
1231 if (err)
1232 goto out_path;
1233 err = mutex_lock_interruptible(&u->bindlock);
1234 if (err)
1235 goto out_unlink;
1236 if (u->addr)
1237 goto out_unlock;
1238
1239 new_hash = unix_bsd_hash(d_backing_inode(dentry));
1240 unix_table_double_lock(net, old_hash, new_hash);
1241 u->path.mnt = mntget(parent.mnt);
1242 u->path.dentry = dget(dentry);
1243 __unix_set_addr_hash(net, sk, addr, new_hash);
1244 unix_table_double_unlock(net, old_hash, new_hash);
1245 unix_insert_bsd_socket(sk);
1246 mutex_unlock(&u->bindlock);
1247 done_path_create(&parent, dentry);
1248 return 0;
1249
1250out_unlock:
1251 mutex_unlock(&u->bindlock);
1252 err = -EINVAL;
1253out_unlink:
1254 /* failed after successful mknod? unlink what we'd created... */
1255 vfs_unlink(idmap, d_inode(parent.dentry), dentry, NULL);
1256out_path:
1257 done_path_create(&parent, dentry);
1258out:
1259 unix_release_addr(addr);
1260 return err == -EEXIST ? -EADDRINUSE : err;
1261}
1262
1263static int unix_bind_abstract(struct sock *sk, struct sockaddr_un *sunaddr,
1264 int addr_len)
1265{
1266 unsigned int new_hash, old_hash = sk->sk_hash;
1267 struct unix_sock *u = unix_sk(sk);
1268 struct net *net = sock_net(sk);
1269 struct unix_address *addr;
1270 int err;
1271
1272 addr = unix_create_addr(sunaddr, addr_len);
1273 if (!addr)
1274 return -ENOMEM;
1275
1276 err = mutex_lock_interruptible(&u->bindlock);
1277 if (err)
1278 goto out;
1279
1280 if (u->addr) {
1281 err = -EINVAL;
1282 goto out_mutex;
1283 }
1284
1285 new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);
1286 unix_table_double_lock(net, old_hash, new_hash);
1287
1288 if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash))
1289 goto out_spin;
1290
1291 __unix_set_addr_hash(net, sk, addr, new_hash);
1292 unix_table_double_unlock(net, old_hash, new_hash);
1293 mutex_unlock(&u->bindlock);
1294 return 0;
1295
1296out_spin:
1297 unix_table_double_unlock(net, old_hash, new_hash);
1298 err = -EADDRINUSE;
1299out_mutex:
1300 mutex_unlock(&u->bindlock);
1301out:
1302 unix_release_addr(addr);
1303 return err;
1304}
1305
1306static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1307{
1308 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1309 struct sock *sk = sock->sk;
1310 int err;
1311
1312 if (addr_len == offsetof(struct sockaddr_un, sun_path) &&
1313 sunaddr->sun_family == AF_UNIX)
1314 return unix_autobind(sk);
1315
1316 err = unix_validate_addr(sunaddr, addr_len);
1317 if (err)
1318 return err;
1319
1320 if (sunaddr->sun_path[0])
1321 err = unix_bind_bsd(sk, sunaddr, addr_len);
1322 else
1323 err = unix_bind_abstract(sk, sunaddr, addr_len);
1324
1325 return err;
1326}
1327
1328static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1329{
1330 if (unlikely(sk1 == sk2) || !sk2) {
1331 unix_state_lock(sk1);
1332 return;
1333 }
1334 if (sk1 > sk2)
1335 swap(sk1, sk2);
1336
1337 unix_state_lock(sk1);
1338 unix_state_lock_nested(sk2, U_LOCK_SECOND);
1339}
1340
1341static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1342{
1343 if (unlikely(sk1 == sk2) || !sk2) {
1344 unix_state_unlock(sk1);
1345 return;
1346 }
1347 unix_state_unlock(sk1);
1348 unix_state_unlock(sk2);
1349}
1350
1351static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1352 int alen, int flags)
1353{
1354 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1355 struct sock *sk = sock->sk;
1356 struct sock *other;
1357 int err;
1358
1359 err = -EINVAL;
1360 if (alen < offsetofend(struct sockaddr, sa_family))
1361 goto out;
1362
1363 if (addr->sa_family != AF_UNSPEC) {
1364 err = unix_validate_addr(sunaddr, alen);
1365 if (err)
1366 goto out;
1367
1368 err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, addr, &alen);
1369 if (err)
1370 goto out;
1371
1372 if ((test_bit(SOCK_PASSCRED, &sock->flags) ||
1373 test_bit(SOCK_PASSPIDFD, &sock->flags)) &&
1374 !unix_sk(sk)->addr) {
1375 err = unix_autobind(sk);
1376 if (err)
1377 goto out;
1378 }
1379
1380restart:
1381 other = unix_find_other(sock_net(sk), sunaddr, alen, sock->type);
1382 if (IS_ERR(other)) {
1383 err = PTR_ERR(other);
1384 goto out;
1385 }
1386
1387 unix_state_double_lock(sk, other);
1388
1389 /* Apparently VFS overslept socket death. Retry. */
1390 if (sock_flag(other, SOCK_DEAD)) {
1391 unix_state_double_unlock(sk, other);
1392 sock_put(other);
1393 goto restart;
1394 }
1395
1396 err = -EPERM;
1397 if (!unix_may_send(sk, other))
1398 goto out_unlock;
1399
1400 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1401 if (err)
1402 goto out_unlock;
1403
1404 sk->sk_state = other->sk_state = TCP_ESTABLISHED;
1405 } else {
1406 /*
1407 * 1003.1g breaking connected state with AF_UNSPEC
1408 */
1409 other = NULL;
1410 unix_state_double_lock(sk, other);
1411 }
1412
1413 /*
1414 * If it was connected, reconnect.
1415 */
1416 if (unix_peer(sk)) {
1417 struct sock *old_peer = unix_peer(sk);
1418
1419 unix_peer(sk) = other;
1420 if (!other)
1421 sk->sk_state = TCP_CLOSE;
1422 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1423
1424 unix_state_double_unlock(sk, other);
1425
1426 if (other != old_peer)
1427 unix_dgram_disconnected(sk, old_peer);
1428 sock_put(old_peer);
1429 } else {
1430 unix_peer(sk) = other;
1431 unix_state_double_unlock(sk, other);
1432 }
1433
1434 return 0;
1435
1436out_unlock:
1437 unix_state_double_unlock(sk, other);
1438 sock_put(other);
1439out:
1440 return err;
1441}
1442
1443static long unix_wait_for_peer(struct sock *other, long timeo)
1444 __releases(&unix_sk(other)->lock)
1445{
1446 struct unix_sock *u = unix_sk(other);
1447 int sched;
1448 DEFINE_WAIT(wait);
1449
1450 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1451
1452 sched = !sock_flag(other, SOCK_DEAD) &&
1453 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1454 unix_recvq_full_lockless(other);
1455
1456 unix_state_unlock(other);
1457
1458 if (sched)
1459 timeo = schedule_timeout(timeo);
1460
1461 finish_wait(&u->peer_wait, &wait);
1462 return timeo;
1463}
1464
1465static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1466 int addr_len, int flags)
1467{
1468 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1469 struct sock *sk = sock->sk, *newsk = NULL, *other = NULL;
1470 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1471 struct net *net = sock_net(sk);
1472 struct sk_buff *skb = NULL;
1473 long timeo;
1474 int err;
1475 int st;
1476
1477 err = unix_validate_addr(sunaddr, addr_len);
1478 if (err)
1479 goto out;
1480
1481 err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, uaddr, &addr_len);
1482 if (err)
1483 goto out;
1484
1485 if ((test_bit(SOCK_PASSCRED, &sock->flags) ||
1486 test_bit(SOCK_PASSPIDFD, &sock->flags)) && !u->addr) {
1487 err = unix_autobind(sk);
1488 if (err)
1489 goto out;
1490 }
1491
1492 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1493
1494 /* First of all allocate resources.
1495 If we will make it after state is locked,
1496 we will have to recheck all again in any case.
1497 */
1498
1499 /* create new sock for complete connection */
1500 newsk = unix_create1(net, NULL, 0, sock->type);
1501 if (IS_ERR(newsk)) {
1502 err = PTR_ERR(newsk);
1503 newsk = NULL;
1504 goto out;
1505 }
1506
1507 err = -ENOMEM;
1508
1509 /* Allocate skb for sending to listening sock */
1510 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1511 if (skb == NULL)
1512 goto out;
1513
1514restart:
1515 /* Find listening sock. */
1516 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type);
1517 if (IS_ERR(other)) {
1518 err = PTR_ERR(other);
1519 other = NULL;
1520 goto out;
1521 }
1522
1523 /* Latch state of peer */
1524 unix_state_lock(other);
1525
1526 /* Apparently VFS overslept socket death. Retry. */
1527 if (sock_flag(other, SOCK_DEAD)) {
1528 unix_state_unlock(other);
1529 sock_put(other);
1530 goto restart;
1531 }
1532
1533 err = -ECONNREFUSED;
1534 if (other->sk_state != TCP_LISTEN)
1535 goto out_unlock;
1536 if (other->sk_shutdown & RCV_SHUTDOWN)
1537 goto out_unlock;
1538
1539 if (unix_recvq_full(other)) {
1540 err = -EAGAIN;
1541 if (!timeo)
1542 goto out_unlock;
1543
1544 timeo = unix_wait_for_peer(other, timeo);
1545
1546 err = sock_intr_errno(timeo);
1547 if (signal_pending(current))
1548 goto out;
1549 sock_put(other);
1550 goto restart;
1551 }
1552
1553 /* Latch our state.
1554
1555 It is tricky place. We need to grab our state lock and cannot
1556 drop lock on peer. It is dangerous because deadlock is
1557 possible. Connect to self case and simultaneous
1558 attempt to connect are eliminated by checking socket
1559 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1560 check this before attempt to grab lock.
1561
1562 Well, and we have to recheck the state after socket locked.
1563 */
1564 st = sk->sk_state;
1565
1566 switch (st) {
1567 case TCP_CLOSE:
1568 /* This is ok... continue with connect */
1569 break;
1570 case TCP_ESTABLISHED:
1571 /* Socket is already connected */
1572 err = -EISCONN;
1573 goto out_unlock;
1574 default:
1575 err = -EINVAL;
1576 goto out_unlock;
1577 }
1578
1579 unix_state_lock_nested(sk, U_LOCK_SECOND);
1580
1581 if (sk->sk_state != st) {
1582 unix_state_unlock(sk);
1583 unix_state_unlock(other);
1584 sock_put(other);
1585 goto restart;
1586 }
1587
1588 err = security_unix_stream_connect(sk, other, newsk);
1589 if (err) {
1590 unix_state_unlock(sk);
1591 goto out_unlock;
1592 }
1593
1594 /* The way is open! Fastly set all the necessary fields... */
1595
1596 sock_hold(sk);
1597 unix_peer(newsk) = sk;
1598 newsk->sk_state = TCP_ESTABLISHED;
1599 newsk->sk_type = sk->sk_type;
1600 init_peercred(newsk);
1601 newu = unix_sk(newsk);
1602 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1603 otheru = unix_sk(other);
1604
1605 /* copy address information from listening to new sock
1606 *
1607 * The contents of *(otheru->addr) and otheru->path
1608 * are seen fully set up here, since we have found
1609 * otheru in hash under its lock. Insertion into the
1610 * hash chain we'd found it in had been done in an
1611 * earlier critical area protected by the chain's lock,
1612 * the same one where we'd set *(otheru->addr) contents,
1613 * as well as otheru->path and otheru->addr itself.
1614 *
1615 * Using smp_store_release() here to set newu->addr
1616 * is enough to make those stores, as well as stores
1617 * to newu->path visible to anyone who gets newu->addr
1618 * by smp_load_acquire(). IOW, the same warranties
1619 * as for unix_sock instances bound in unix_bind() or
1620 * in unix_autobind().
1621 */
1622 if (otheru->path.dentry) {
1623 path_get(&otheru->path);
1624 newu->path = otheru->path;
1625 }
1626 refcount_inc(&otheru->addr->refcnt);
1627 smp_store_release(&newu->addr, otheru->addr);
1628
1629 /* Set credentials */
1630 copy_peercred(sk, other);
1631
1632 sock->state = SS_CONNECTED;
1633 sk->sk_state = TCP_ESTABLISHED;
1634 sock_hold(newsk);
1635
1636 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1637 unix_peer(sk) = newsk;
1638
1639 unix_state_unlock(sk);
1640
1641 /* take ten and send info to listening sock */
1642 spin_lock(&other->sk_receive_queue.lock);
1643 __skb_queue_tail(&other->sk_receive_queue, skb);
1644 spin_unlock(&other->sk_receive_queue.lock);
1645 unix_state_unlock(other);
1646 other->sk_data_ready(other);
1647 sock_put(other);
1648 return 0;
1649
1650out_unlock:
1651 if (other)
1652 unix_state_unlock(other);
1653
1654out:
1655 kfree_skb(skb);
1656 if (newsk)
1657 unix_release_sock(newsk, 0);
1658 if (other)
1659 sock_put(other);
1660 return err;
1661}
1662
1663static int unix_socketpair(struct socket *socka, struct socket *sockb)
1664{
1665 struct sock *ska = socka->sk, *skb = sockb->sk;
1666
1667 /* Join our sockets back to back */
1668 sock_hold(ska);
1669 sock_hold(skb);
1670 unix_peer(ska) = skb;
1671 unix_peer(skb) = ska;
1672 init_peercred(ska);
1673 init_peercred(skb);
1674
1675 ska->sk_state = TCP_ESTABLISHED;
1676 skb->sk_state = TCP_ESTABLISHED;
1677 socka->state = SS_CONNECTED;
1678 sockb->state = SS_CONNECTED;
1679 return 0;
1680}
1681
1682static void unix_sock_inherit_flags(const struct socket *old,
1683 struct socket *new)
1684{
1685 if (test_bit(SOCK_PASSCRED, &old->flags))
1686 set_bit(SOCK_PASSCRED, &new->flags);
1687 if (test_bit(SOCK_PASSPIDFD, &old->flags))
1688 set_bit(SOCK_PASSPIDFD, &new->flags);
1689 if (test_bit(SOCK_PASSSEC, &old->flags))
1690 set_bit(SOCK_PASSSEC, &new->flags);
1691}
1692
1693static int unix_accept(struct socket *sock, struct socket *newsock, int flags,
1694 bool kern)
1695{
1696 struct sock *sk = sock->sk;
1697 struct sock *tsk;
1698 struct sk_buff *skb;
1699 int err;
1700
1701 err = -EOPNOTSUPP;
1702 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1703 goto out;
1704
1705 err = -EINVAL;
1706 if (sk->sk_state != TCP_LISTEN)
1707 goto out;
1708
1709 /* If socket state is TCP_LISTEN it cannot change (for now...),
1710 * so that no locks are necessary.
1711 */
1712
1713 skb = skb_recv_datagram(sk, (flags & O_NONBLOCK) ? MSG_DONTWAIT : 0,
1714 &err);
1715 if (!skb) {
1716 /* This means receive shutdown. */
1717 if (err == 0)
1718 err = -EINVAL;
1719 goto out;
1720 }
1721
1722 tsk = skb->sk;
1723 skb_free_datagram(sk, skb);
1724 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1725
1726 /* attach accepted sock to socket */
1727 unix_state_lock(tsk);
1728 newsock->state = SS_CONNECTED;
1729 unix_sock_inherit_flags(sock, newsock);
1730 sock_graft(tsk, newsock);
1731 unix_state_unlock(tsk);
1732 return 0;
1733
1734out:
1735 return err;
1736}
1737
1738
1739static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1740{
1741 struct sock *sk = sock->sk;
1742 struct unix_address *addr;
1743 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1744 int err = 0;
1745
1746 if (peer) {
1747 sk = unix_peer_get(sk);
1748
1749 err = -ENOTCONN;
1750 if (!sk)
1751 goto out;
1752 err = 0;
1753 } else {
1754 sock_hold(sk);
1755 }
1756
1757 addr = smp_load_acquire(&unix_sk(sk)->addr);
1758 if (!addr) {
1759 sunaddr->sun_family = AF_UNIX;
1760 sunaddr->sun_path[0] = 0;
1761 err = offsetof(struct sockaddr_un, sun_path);
1762 } else {
1763 err = addr->len;
1764 memcpy(sunaddr, addr->name, addr->len);
1765
1766 if (peer)
1767 BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err,
1768 CGROUP_UNIX_GETPEERNAME);
1769 else
1770 BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err,
1771 CGROUP_UNIX_GETSOCKNAME);
1772 }
1773 sock_put(sk);
1774out:
1775 return err;
1776}
1777
1778static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb)
1779{
1780 scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1781
1782 /*
1783 * Garbage collection of unix sockets starts by selecting a set of
1784 * candidate sockets which have reference only from being in flight
1785 * (total_refs == inflight_refs). This condition is checked once during
1786 * the candidate collection phase, and candidates are marked as such, so
1787 * that non-candidates can later be ignored. While inflight_refs is
1788 * protected by unix_gc_lock, total_refs (file count) is not, hence this
1789 * is an instantaneous decision.
1790 *
1791 * Once a candidate, however, the socket must not be reinstalled into a
1792 * file descriptor while the garbage collection is in progress.
1793 *
1794 * If the above conditions are met, then the directed graph of
1795 * candidates (*) does not change while unix_gc_lock is held.
1796 *
1797 * Any operations that changes the file count through file descriptors
1798 * (dup, close, sendmsg) does not change the graph since candidates are
1799 * not installed in fds.
1800 *
1801 * Dequeing a candidate via recvmsg would install it into an fd, but
1802 * that takes unix_gc_lock to decrement the inflight count, so it's
1803 * serialized with garbage collection.
1804 *
1805 * MSG_PEEK is special in that it does not change the inflight count,
1806 * yet does install the socket into an fd. The following lock/unlock
1807 * pair is to ensure serialization with garbage collection. It must be
1808 * done between incrementing the file count and installing the file into
1809 * an fd.
1810 *
1811 * If garbage collection starts after the barrier provided by the
1812 * lock/unlock, then it will see the elevated refcount and not mark this
1813 * as a candidate. If a garbage collection is already in progress
1814 * before the file count was incremented, then the lock/unlock pair will
1815 * ensure that garbage collection is finished before progressing to
1816 * installing the fd.
1817 *
1818 * (*) A -> B where B is on the queue of A or B is on the queue of C
1819 * which is on the queue of listening socket A.
1820 */
1821 spin_lock(&unix_gc_lock);
1822 spin_unlock(&unix_gc_lock);
1823}
1824
1825static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1826{
1827 int err = 0;
1828
1829 UNIXCB(skb).pid = get_pid(scm->pid);
1830 UNIXCB(skb).uid = scm->creds.uid;
1831 UNIXCB(skb).gid = scm->creds.gid;
1832 UNIXCB(skb).fp = NULL;
1833 unix_get_secdata(scm, skb);
1834 if (scm->fp && send_fds)
1835 err = unix_attach_fds(scm, skb);
1836
1837 skb->destructor = unix_destruct_scm;
1838 return err;
1839}
1840
1841static bool unix_passcred_enabled(const struct socket *sock,
1842 const struct sock *other)
1843{
1844 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1845 test_bit(SOCK_PASSPIDFD, &sock->flags) ||
1846 !other->sk_socket ||
1847 test_bit(SOCK_PASSCRED, &other->sk_socket->flags) ||
1848 test_bit(SOCK_PASSPIDFD, &other->sk_socket->flags);
1849}
1850
1851/*
1852 * Some apps rely on write() giving SCM_CREDENTIALS
1853 * We include credentials if source or destination socket
1854 * asserted SOCK_PASSCRED.
1855 */
1856static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1857 const struct sock *other)
1858{
1859 if (UNIXCB(skb).pid)
1860 return;
1861 if (unix_passcred_enabled(sock, other)) {
1862 UNIXCB(skb).pid = get_pid(task_tgid(current));
1863 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1864 }
1865}
1866
1867static bool unix_skb_scm_eq(struct sk_buff *skb,
1868 struct scm_cookie *scm)
1869{
1870 return UNIXCB(skb).pid == scm->pid &&
1871 uid_eq(UNIXCB(skb).uid, scm->creds.uid) &&
1872 gid_eq(UNIXCB(skb).gid, scm->creds.gid) &&
1873 unix_secdata_eq(scm, skb);
1874}
1875
1876static void scm_stat_add(struct sock *sk, struct sk_buff *skb)
1877{
1878 struct scm_fp_list *fp = UNIXCB(skb).fp;
1879 struct unix_sock *u = unix_sk(sk);
1880
1881 if (unlikely(fp && fp->count))
1882 atomic_add(fp->count, &u->scm_stat.nr_fds);
1883}
1884
1885static void scm_stat_del(struct sock *sk, struct sk_buff *skb)
1886{
1887 struct scm_fp_list *fp = UNIXCB(skb).fp;
1888 struct unix_sock *u = unix_sk(sk);
1889
1890 if (unlikely(fp && fp->count))
1891 atomic_sub(fp->count, &u->scm_stat.nr_fds);
1892}
1893
1894/*
1895 * Send AF_UNIX data.
1896 */
1897
1898static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1899 size_t len)
1900{
1901 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1902 struct sock *sk = sock->sk, *other = NULL;
1903 struct unix_sock *u = unix_sk(sk);
1904 struct scm_cookie scm;
1905 struct sk_buff *skb;
1906 int data_len = 0;
1907 int sk_locked;
1908 long timeo;
1909 int err;
1910
1911 wait_for_unix_gc();
1912 err = scm_send(sock, msg, &scm, false);
1913 if (err < 0)
1914 return err;
1915
1916 err = -EOPNOTSUPP;
1917 if (msg->msg_flags&MSG_OOB)
1918 goto out;
1919
1920 if (msg->msg_namelen) {
1921 err = unix_validate_addr(sunaddr, msg->msg_namelen);
1922 if (err)
1923 goto out;
1924
1925 err = BPF_CGROUP_RUN_PROG_UNIX_SENDMSG_LOCK(sk,
1926 msg->msg_name,
1927 &msg->msg_namelen,
1928 NULL);
1929 if (err)
1930 goto out;
1931 } else {
1932 sunaddr = NULL;
1933 err = -ENOTCONN;
1934 other = unix_peer_get(sk);
1935 if (!other)
1936 goto out;
1937 }
1938
1939 if ((test_bit(SOCK_PASSCRED, &sock->flags) ||
1940 test_bit(SOCK_PASSPIDFD, &sock->flags)) && !u->addr) {
1941 err = unix_autobind(sk);
1942 if (err)
1943 goto out;
1944 }
1945
1946 err = -EMSGSIZE;
1947 if (len > sk->sk_sndbuf - 32)
1948 goto out;
1949
1950 if (len > SKB_MAX_ALLOC) {
1951 data_len = min_t(size_t,
1952 len - SKB_MAX_ALLOC,
1953 MAX_SKB_FRAGS * PAGE_SIZE);
1954 data_len = PAGE_ALIGN(data_len);
1955
1956 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1957 }
1958
1959 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1960 msg->msg_flags & MSG_DONTWAIT, &err,
1961 PAGE_ALLOC_COSTLY_ORDER);
1962 if (skb == NULL)
1963 goto out;
1964
1965 err = unix_scm_to_skb(&scm, skb, true);
1966 if (err < 0)
1967 goto out_free;
1968
1969 skb_put(skb, len - data_len);
1970 skb->data_len = data_len;
1971 skb->len = len;
1972 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1973 if (err)
1974 goto out_free;
1975
1976 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1977
1978restart:
1979 if (!other) {
1980 err = -ECONNRESET;
1981 if (sunaddr == NULL)
1982 goto out_free;
1983
1984 other = unix_find_other(sock_net(sk), sunaddr, msg->msg_namelen,
1985 sk->sk_type);
1986 if (IS_ERR(other)) {
1987 err = PTR_ERR(other);
1988 other = NULL;
1989 goto out_free;
1990 }
1991 }
1992
1993 if (sk_filter(other, skb) < 0) {
1994 /* Toss the packet but do not return any error to the sender */
1995 err = len;
1996 goto out_free;
1997 }
1998
1999 sk_locked = 0;
2000 unix_state_lock(other);
2001restart_locked:
2002 err = -EPERM;
2003 if (!unix_may_send(sk, other))
2004 goto out_unlock;
2005
2006 if (unlikely(sock_flag(other, SOCK_DEAD))) {
2007 /*
2008 * Check with 1003.1g - what should
2009 * datagram error
2010 */
2011 unix_state_unlock(other);
2012 sock_put(other);
2013
2014 if (!sk_locked)
2015 unix_state_lock(sk);
2016
2017 err = 0;
2018 if (sk->sk_type == SOCK_SEQPACKET) {
2019 /* We are here only when racing with unix_release_sock()
2020 * is clearing @other. Never change state to TCP_CLOSE
2021 * unlike SOCK_DGRAM wants.
2022 */
2023 unix_state_unlock(sk);
2024 err = -EPIPE;
2025 } else if (unix_peer(sk) == other) {
2026 unix_peer(sk) = NULL;
2027 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
2028
2029 sk->sk_state = TCP_CLOSE;
2030 unix_state_unlock(sk);
2031
2032 unix_dgram_disconnected(sk, other);
2033 sock_put(other);
2034 err = -ECONNREFUSED;
2035 } else {
2036 unix_state_unlock(sk);
2037 }
2038
2039 other = NULL;
2040 if (err)
2041 goto out_free;
2042 goto restart;
2043 }
2044
2045 err = -EPIPE;
2046 if (other->sk_shutdown & RCV_SHUTDOWN)
2047 goto out_unlock;
2048
2049 if (sk->sk_type != SOCK_SEQPACKET) {
2050 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
2051 if (err)
2052 goto out_unlock;
2053 }
2054
2055 /* other == sk && unix_peer(other) != sk if
2056 * - unix_peer(sk) == NULL, destination address bound to sk
2057 * - unix_peer(sk) == sk by time of get but disconnected before lock
2058 */
2059 if (other != sk &&
2060 unlikely(unix_peer(other) != sk &&
2061 unix_recvq_full_lockless(other))) {
2062 if (timeo) {
2063 timeo = unix_wait_for_peer(other, timeo);
2064
2065 err = sock_intr_errno(timeo);
2066 if (signal_pending(current))
2067 goto out_free;
2068
2069 goto restart;
2070 }
2071
2072 if (!sk_locked) {
2073 unix_state_unlock(other);
2074 unix_state_double_lock(sk, other);
2075 }
2076
2077 if (unix_peer(sk) != other ||
2078 unix_dgram_peer_wake_me(sk, other)) {
2079 err = -EAGAIN;
2080 sk_locked = 1;
2081 goto out_unlock;
2082 }
2083
2084 if (!sk_locked) {
2085 sk_locked = 1;
2086 goto restart_locked;
2087 }
2088 }
2089
2090 if (unlikely(sk_locked))
2091 unix_state_unlock(sk);
2092
2093 if (sock_flag(other, SOCK_RCVTSTAMP))
2094 __net_timestamp(skb);
2095 maybe_add_creds(skb, sock, other);
2096 scm_stat_add(other, skb);
2097 skb_queue_tail(&other->sk_receive_queue, skb);
2098 unix_state_unlock(other);
2099 other->sk_data_ready(other);
2100 sock_put(other);
2101 scm_destroy(&scm);
2102 return len;
2103
2104out_unlock:
2105 if (sk_locked)
2106 unix_state_unlock(sk);
2107 unix_state_unlock(other);
2108out_free:
2109 kfree_skb(skb);
2110out:
2111 if (other)
2112 sock_put(other);
2113 scm_destroy(&scm);
2114 return err;
2115}
2116
2117/* We use paged skbs for stream sockets, and limit occupancy to 32768
2118 * bytes, and a minimum of a full page.
2119 */
2120#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
2121
2122#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2123static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other,
2124 struct scm_cookie *scm, bool fds_sent)
2125{
2126 struct unix_sock *ousk = unix_sk(other);
2127 struct sk_buff *skb;
2128 int err = 0;
2129
2130 skb = sock_alloc_send_skb(sock->sk, 1, msg->msg_flags & MSG_DONTWAIT, &err);
2131
2132 if (!skb)
2133 return err;
2134
2135 err = unix_scm_to_skb(scm, skb, !fds_sent);
2136 if (err < 0) {
2137 kfree_skb(skb);
2138 return err;
2139 }
2140 skb_put(skb, 1);
2141 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, 1);
2142
2143 if (err) {
2144 kfree_skb(skb);
2145 return err;
2146 }
2147
2148 unix_state_lock(other);
2149
2150 if (sock_flag(other, SOCK_DEAD) ||
2151 (other->sk_shutdown & RCV_SHUTDOWN)) {
2152 unix_state_unlock(other);
2153 kfree_skb(skb);
2154 return -EPIPE;
2155 }
2156
2157 maybe_add_creds(skb, sock, other);
2158 skb_get(skb);
2159
2160 if (ousk->oob_skb)
2161 consume_skb(ousk->oob_skb);
2162
2163 WRITE_ONCE(ousk->oob_skb, skb);
2164
2165 scm_stat_add(other, skb);
2166 skb_queue_tail(&other->sk_receive_queue, skb);
2167 sk_send_sigurg(other);
2168 unix_state_unlock(other);
2169 other->sk_data_ready(other);
2170
2171 return err;
2172}
2173#endif
2174
2175static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
2176 size_t len)
2177{
2178 struct sock *sk = sock->sk;
2179 struct sock *other = NULL;
2180 int err, size;
2181 struct sk_buff *skb;
2182 int sent = 0;
2183 struct scm_cookie scm;
2184 bool fds_sent = false;
2185 int data_len;
2186
2187 wait_for_unix_gc();
2188 err = scm_send(sock, msg, &scm, false);
2189 if (err < 0)
2190 return err;
2191
2192 err = -EOPNOTSUPP;
2193 if (msg->msg_flags & MSG_OOB) {
2194#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2195 if (len)
2196 len--;
2197 else
2198#endif
2199 goto out_err;
2200 }
2201
2202 if (msg->msg_namelen) {
2203 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
2204 goto out_err;
2205 } else {
2206 err = -ENOTCONN;
2207 other = unix_peer(sk);
2208 if (!other)
2209 goto out_err;
2210 }
2211
2212 if (sk->sk_shutdown & SEND_SHUTDOWN)
2213 goto pipe_err;
2214
2215 while (sent < len) {
2216 size = len - sent;
2217
2218 if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {
2219 skb = sock_alloc_send_pskb(sk, 0, 0,
2220 msg->msg_flags & MSG_DONTWAIT,
2221 &err, 0);
2222 } else {
2223 /* Keep two messages in the pipe so it schedules better */
2224 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
2225
2226 /* allow fallback to order-0 allocations */
2227 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
2228
2229 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
2230
2231 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
2232
2233 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
2234 msg->msg_flags & MSG_DONTWAIT, &err,
2235 get_order(UNIX_SKB_FRAGS_SZ));
2236 }
2237 if (!skb)
2238 goto out_err;
2239
2240 /* Only send the fds in the first buffer */
2241 err = unix_scm_to_skb(&scm, skb, !fds_sent);
2242 if (err < 0) {
2243 kfree_skb(skb);
2244 goto out_err;
2245 }
2246 fds_sent = true;
2247
2248 if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {
2249 err = skb_splice_from_iter(skb, &msg->msg_iter, size,
2250 sk->sk_allocation);
2251 if (err < 0) {
2252 kfree_skb(skb);
2253 goto out_err;
2254 }
2255 size = err;
2256 refcount_add(size, &sk->sk_wmem_alloc);
2257 } else {
2258 skb_put(skb, size - data_len);
2259 skb->data_len = data_len;
2260 skb->len = size;
2261 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
2262 if (err) {
2263 kfree_skb(skb);
2264 goto out_err;
2265 }
2266 }
2267
2268 unix_state_lock(other);
2269
2270 if (sock_flag(other, SOCK_DEAD) ||
2271 (other->sk_shutdown & RCV_SHUTDOWN))
2272 goto pipe_err_free;
2273
2274 maybe_add_creds(skb, sock, other);
2275 scm_stat_add(other, skb);
2276 skb_queue_tail(&other->sk_receive_queue, skb);
2277 unix_state_unlock(other);
2278 other->sk_data_ready(other);
2279 sent += size;
2280 }
2281
2282#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2283 if (msg->msg_flags & MSG_OOB) {
2284 err = queue_oob(sock, msg, other, &scm, fds_sent);
2285 if (err)
2286 goto out_err;
2287 sent++;
2288 }
2289#endif
2290
2291 scm_destroy(&scm);
2292
2293 return sent;
2294
2295pipe_err_free:
2296 unix_state_unlock(other);
2297 kfree_skb(skb);
2298pipe_err:
2299 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
2300 send_sig(SIGPIPE, current, 0);
2301 err = -EPIPE;
2302out_err:
2303 scm_destroy(&scm);
2304 return sent ? : err;
2305}
2306
2307static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2308 size_t len)
2309{
2310 int err;
2311 struct sock *sk = sock->sk;
2312
2313 err = sock_error(sk);
2314 if (err)
2315 return err;
2316
2317 if (sk->sk_state != TCP_ESTABLISHED)
2318 return -ENOTCONN;
2319
2320 if (msg->msg_namelen)
2321 msg->msg_namelen = 0;
2322
2323 return unix_dgram_sendmsg(sock, msg, len);
2324}
2325
2326static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2327 size_t size, int flags)
2328{
2329 struct sock *sk = sock->sk;
2330
2331 if (sk->sk_state != TCP_ESTABLISHED)
2332 return -ENOTCONN;
2333
2334 return unix_dgram_recvmsg(sock, msg, size, flags);
2335}
2336
2337static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2338{
2339 struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
2340
2341 if (addr) {
2342 msg->msg_namelen = addr->len;
2343 memcpy(msg->msg_name, addr->name, addr->len);
2344 }
2345}
2346
2347int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size,
2348 int flags)
2349{
2350 struct scm_cookie scm;
2351 struct socket *sock = sk->sk_socket;
2352 struct unix_sock *u = unix_sk(sk);
2353 struct sk_buff *skb, *last;
2354 long timeo;
2355 int skip;
2356 int err;
2357
2358 err = -EOPNOTSUPP;
2359 if (flags&MSG_OOB)
2360 goto out;
2361
2362 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2363
2364 do {
2365 mutex_lock(&u->iolock);
2366
2367 skip = sk_peek_offset(sk, flags);
2368 skb = __skb_try_recv_datagram(sk, &sk->sk_receive_queue, flags,
2369 &skip, &err, &last);
2370 if (skb) {
2371 if (!(flags & MSG_PEEK))
2372 scm_stat_del(sk, skb);
2373 break;
2374 }
2375
2376 mutex_unlock(&u->iolock);
2377
2378 if (err != -EAGAIN)
2379 break;
2380 } while (timeo &&
2381 !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue,
2382 &err, &timeo, last));
2383
2384 if (!skb) { /* implies iolock unlocked */
2385 unix_state_lock(sk);
2386 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2387 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2388 (sk->sk_shutdown & RCV_SHUTDOWN))
2389 err = 0;
2390 unix_state_unlock(sk);
2391 goto out;
2392 }
2393
2394 if (wq_has_sleeper(&u->peer_wait))
2395 wake_up_interruptible_sync_poll(&u->peer_wait,
2396 EPOLLOUT | EPOLLWRNORM |
2397 EPOLLWRBAND);
2398
2399 if (msg->msg_name) {
2400 unix_copy_addr(msg, skb->sk);
2401
2402 BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk,
2403 msg->msg_name,
2404 &msg->msg_namelen);
2405 }
2406
2407 if (size > skb->len - skip)
2408 size = skb->len - skip;
2409 else if (size < skb->len - skip)
2410 msg->msg_flags |= MSG_TRUNC;
2411
2412 err = skb_copy_datagram_msg(skb, skip, msg, size);
2413 if (err)
2414 goto out_free;
2415
2416 if (sock_flag(sk, SOCK_RCVTSTAMP))
2417 __sock_recv_timestamp(msg, sk, skb);
2418
2419 memset(&scm, 0, sizeof(scm));
2420
2421 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2422 unix_set_secdata(&scm, skb);
2423
2424 if (!(flags & MSG_PEEK)) {
2425 if (UNIXCB(skb).fp)
2426 unix_detach_fds(&scm, skb);
2427
2428 sk_peek_offset_bwd(sk, skb->len);
2429 } else {
2430 /* It is questionable: on PEEK we could:
2431 - do not return fds - good, but too simple 8)
2432 - return fds, and do not return them on read (old strategy,
2433 apparently wrong)
2434 - clone fds (I chose it for now, it is the most universal
2435 solution)
2436
2437 POSIX 1003.1g does not actually define this clearly
2438 at all. POSIX 1003.1g doesn't define a lot of things
2439 clearly however!
2440
2441 */
2442
2443 sk_peek_offset_fwd(sk, size);
2444
2445 if (UNIXCB(skb).fp)
2446 unix_peek_fds(&scm, skb);
2447 }
2448 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2449
2450 scm_recv_unix(sock, msg, &scm, flags);
2451
2452out_free:
2453 skb_free_datagram(sk, skb);
2454 mutex_unlock(&u->iolock);
2455out:
2456 return err;
2457}
2458
2459static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
2460 int flags)
2461{
2462 struct sock *sk = sock->sk;
2463
2464#ifdef CONFIG_BPF_SYSCALL
2465 const struct proto *prot = READ_ONCE(sk->sk_prot);
2466
2467 if (prot != &unix_dgram_proto)
2468 return prot->recvmsg(sk, msg, size, flags, NULL);
2469#endif
2470 return __unix_dgram_recvmsg(sk, msg, size, flags);
2471}
2472
2473static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
2474{
2475 struct unix_sock *u = unix_sk(sk);
2476 struct sk_buff *skb;
2477 int err;
2478
2479 mutex_lock(&u->iolock);
2480 skb = skb_recv_datagram(sk, MSG_DONTWAIT, &err);
2481 mutex_unlock(&u->iolock);
2482 if (!skb)
2483 return err;
2484
2485 return recv_actor(sk, skb);
2486}
2487
2488/*
2489 * Sleep until more data has arrived. But check for races..
2490 */
2491static long unix_stream_data_wait(struct sock *sk, long timeo,
2492 struct sk_buff *last, unsigned int last_len,
2493 bool freezable)
2494{
2495 unsigned int state = TASK_INTERRUPTIBLE | freezable * TASK_FREEZABLE;
2496 struct sk_buff *tail;
2497 DEFINE_WAIT(wait);
2498
2499 unix_state_lock(sk);
2500
2501 for (;;) {
2502 prepare_to_wait(sk_sleep(sk), &wait, state);
2503
2504 tail = skb_peek_tail(&sk->sk_receive_queue);
2505 if (tail != last ||
2506 (tail && tail->len != last_len) ||
2507 sk->sk_err ||
2508 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2509 signal_pending(current) ||
2510 !timeo)
2511 break;
2512
2513 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2514 unix_state_unlock(sk);
2515 timeo = schedule_timeout(timeo);
2516 unix_state_lock(sk);
2517
2518 if (sock_flag(sk, SOCK_DEAD))
2519 break;
2520
2521 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2522 }
2523
2524 finish_wait(sk_sleep(sk), &wait);
2525 unix_state_unlock(sk);
2526 return timeo;
2527}
2528
2529static unsigned int unix_skb_len(const struct sk_buff *skb)
2530{
2531 return skb->len - UNIXCB(skb).consumed;
2532}
2533
2534struct unix_stream_read_state {
2535 int (*recv_actor)(struct sk_buff *, int, int,
2536 struct unix_stream_read_state *);
2537 struct socket *socket;
2538 struct msghdr *msg;
2539 struct pipe_inode_info *pipe;
2540 size_t size;
2541 int flags;
2542 unsigned int splice_flags;
2543};
2544
2545#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2546static int unix_stream_recv_urg(struct unix_stream_read_state *state)
2547{
2548 struct socket *sock = state->socket;
2549 struct sock *sk = sock->sk;
2550 struct unix_sock *u = unix_sk(sk);
2551 int chunk = 1;
2552 struct sk_buff *oob_skb;
2553
2554 mutex_lock(&u->iolock);
2555 unix_state_lock(sk);
2556
2557 if (sock_flag(sk, SOCK_URGINLINE) || !u->oob_skb) {
2558 unix_state_unlock(sk);
2559 mutex_unlock(&u->iolock);
2560 return -EINVAL;
2561 }
2562
2563 oob_skb = u->oob_skb;
2564
2565 if (!(state->flags & MSG_PEEK))
2566 WRITE_ONCE(u->oob_skb, NULL);
2567 else
2568 skb_get(oob_skb);
2569 unix_state_unlock(sk);
2570
2571 chunk = state->recv_actor(oob_skb, 0, chunk, state);
2572
2573 if (!(state->flags & MSG_PEEK))
2574 UNIXCB(oob_skb).consumed += 1;
2575
2576 consume_skb(oob_skb);
2577
2578 mutex_unlock(&u->iolock);
2579
2580 if (chunk < 0)
2581 return -EFAULT;
2582
2583 state->msg->msg_flags |= MSG_OOB;
2584 return 1;
2585}
2586
2587static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
2588 int flags, int copied)
2589{
2590 struct unix_sock *u = unix_sk(sk);
2591
2592 if (!unix_skb_len(skb) && !(flags & MSG_PEEK)) {
2593 skb_unlink(skb, &sk->sk_receive_queue);
2594 consume_skb(skb);
2595 skb = NULL;
2596 } else {
2597 if (skb == u->oob_skb) {
2598 if (copied) {
2599 skb = NULL;
2600 } else if (sock_flag(sk, SOCK_URGINLINE)) {
2601 if (!(flags & MSG_PEEK)) {
2602 WRITE_ONCE(u->oob_skb, NULL);
2603 consume_skb(skb);
2604 }
2605 } else if (!(flags & MSG_PEEK)) {
2606 skb_unlink(skb, &sk->sk_receive_queue);
2607 consume_skb(skb);
2608 skb = skb_peek(&sk->sk_receive_queue);
2609 }
2610 }
2611 }
2612 return skb;
2613}
2614#endif
2615
2616static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
2617{
2618 if (unlikely(sk->sk_state != TCP_ESTABLISHED))
2619 return -ENOTCONN;
2620
2621 return unix_read_skb(sk, recv_actor);
2622}
2623
2624static int unix_stream_read_generic(struct unix_stream_read_state *state,
2625 bool freezable)
2626{
2627 struct scm_cookie scm;
2628 struct socket *sock = state->socket;
2629 struct sock *sk = sock->sk;
2630 struct unix_sock *u = unix_sk(sk);
2631 int copied = 0;
2632 int flags = state->flags;
2633 int noblock = flags & MSG_DONTWAIT;
2634 bool check_creds = false;
2635 int target;
2636 int err = 0;
2637 long timeo;
2638 int skip;
2639 size_t size = state->size;
2640 unsigned int last_len;
2641
2642 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2643 err = -EINVAL;
2644 goto out;
2645 }
2646
2647 if (unlikely(flags & MSG_OOB)) {
2648 err = -EOPNOTSUPP;
2649#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2650 err = unix_stream_recv_urg(state);
2651#endif
2652 goto out;
2653 }
2654
2655 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2656 timeo = sock_rcvtimeo(sk, noblock);
2657
2658 memset(&scm, 0, sizeof(scm));
2659
2660 /* Lock the socket to prevent queue disordering
2661 * while sleeps in memcpy_tomsg
2662 */
2663 mutex_lock(&u->iolock);
2664
2665 skip = max(sk_peek_offset(sk, flags), 0);
2666
2667 do {
2668 int chunk;
2669 bool drop_skb;
2670 struct sk_buff *skb, *last;
2671
2672redo:
2673 unix_state_lock(sk);
2674 if (sock_flag(sk, SOCK_DEAD)) {
2675 err = -ECONNRESET;
2676 goto unlock;
2677 }
2678 last = skb = skb_peek(&sk->sk_receive_queue);
2679 last_len = last ? last->len : 0;
2680
2681#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2682 if (skb) {
2683 skb = manage_oob(skb, sk, flags, copied);
2684 if (!skb) {
2685 unix_state_unlock(sk);
2686 if (copied)
2687 break;
2688 goto redo;
2689 }
2690 }
2691#endif
2692again:
2693 if (skb == NULL) {
2694 if (copied >= target)
2695 goto unlock;
2696
2697 /*
2698 * POSIX 1003.1g mandates this order.
2699 */
2700
2701 err = sock_error(sk);
2702 if (err)
2703 goto unlock;
2704 if (sk->sk_shutdown & RCV_SHUTDOWN)
2705 goto unlock;
2706
2707 unix_state_unlock(sk);
2708 if (!timeo) {
2709 err = -EAGAIN;
2710 break;
2711 }
2712
2713 mutex_unlock(&u->iolock);
2714
2715 timeo = unix_stream_data_wait(sk, timeo, last,
2716 last_len, freezable);
2717
2718 if (signal_pending(current)) {
2719 err = sock_intr_errno(timeo);
2720 scm_destroy(&scm);
2721 goto out;
2722 }
2723
2724 mutex_lock(&u->iolock);
2725 goto redo;
2726unlock:
2727 unix_state_unlock(sk);
2728 break;
2729 }
2730
2731 while (skip >= unix_skb_len(skb)) {
2732 skip -= unix_skb_len(skb);
2733 last = skb;
2734 last_len = skb->len;
2735 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2736 if (!skb)
2737 goto again;
2738 }
2739
2740 unix_state_unlock(sk);
2741
2742 if (check_creds) {
2743 /* Never glue messages from different writers */
2744 if (!unix_skb_scm_eq(skb, &scm))
2745 break;
2746 } else if (test_bit(SOCK_PASSCRED, &sock->flags) ||
2747 test_bit(SOCK_PASSPIDFD, &sock->flags)) {
2748 /* Copy credentials */
2749 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2750 unix_set_secdata(&scm, skb);
2751 check_creds = true;
2752 }
2753
2754 /* Copy address just once */
2755 if (state->msg && state->msg->msg_name) {
2756 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2757 state->msg->msg_name);
2758 unix_copy_addr(state->msg, skb->sk);
2759
2760 BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk,
2761 state->msg->msg_name,
2762 &state->msg->msg_namelen);
2763
2764 sunaddr = NULL;
2765 }
2766
2767 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2768 skb_get(skb);
2769 chunk = state->recv_actor(skb, skip, chunk, state);
2770 drop_skb = !unix_skb_len(skb);
2771 /* skb is only safe to use if !drop_skb */
2772 consume_skb(skb);
2773 if (chunk < 0) {
2774 if (copied == 0)
2775 copied = -EFAULT;
2776 break;
2777 }
2778 copied += chunk;
2779 size -= chunk;
2780
2781 if (drop_skb) {
2782 /* the skb was touched by a concurrent reader;
2783 * we should not expect anything from this skb
2784 * anymore and assume it invalid - we can be
2785 * sure it was dropped from the socket queue
2786 *
2787 * let's report a short read
2788 */
2789 err = 0;
2790 break;
2791 }
2792
2793 /* Mark read part of skb as used */
2794 if (!(flags & MSG_PEEK)) {
2795 UNIXCB(skb).consumed += chunk;
2796
2797 sk_peek_offset_bwd(sk, chunk);
2798
2799 if (UNIXCB(skb).fp) {
2800 scm_stat_del(sk, skb);
2801 unix_detach_fds(&scm, skb);
2802 }
2803
2804 if (unix_skb_len(skb))
2805 break;
2806
2807 skb_unlink(skb, &sk->sk_receive_queue);
2808 consume_skb(skb);
2809
2810 if (scm.fp)
2811 break;
2812 } else {
2813 /* It is questionable, see note in unix_dgram_recvmsg.
2814 */
2815 if (UNIXCB(skb).fp)
2816 unix_peek_fds(&scm, skb);
2817
2818 sk_peek_offset_fwd(sk, chunk);
2819
2820 if (UNIXCB(skb).fp)
2821 break;
2822
2823 skip = 0;
2824 last = skb;
2825 last_len = skb->len;
2826 unix_state_lock(sk);
2827 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2828 if (skb)
2829 goto again;
2830 unix_state_unlock(sk);
2831 break;
2832 }
2833 } while (size);
2834
2835 mutex_unlock(&u->iolock);
2836 if (state->msg)
2837 scm_recv_unix(sock, state->msg, &scm, flags);
2838 else
2839 scm_destroy(&scm);
2840out:
2841 return copied ? : err;
2842}
2843
2844static int unix_stream_read_actor(struct sk_buff *skb,
2845 int skip, int chunk,
2846 struct unix_stream_read_state *state)
2847{
2848 int ret;
2849
2850 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2851 state->msg, chunk);
2852 return ret ?: chunk;
2853}
2854
2855int __unix_stream_recvmsg(struct sock *sk, struct msghdr *msg,
2856 size_t size, int flags)
2857{
2858 struct unix_stream_read_state state = {
2859 .recv_actor = unix_stream_read_actor,
2860 .socket = sk->sk_socket,
2861 .msg = msg,
2862 .size = size,
2863 .flags = flags
2864 };
2865
2866 return unix_stream_read_generic(&state, true);
2867}
2868
2869static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2870 size_t size, int flags)
2871{
2872 struct unix_stream_read_state state = {
2873 .recv_actor = unix_stream_read_actor,
2874 .socket = sock,
2875 .msg = msg,
2876 .size = size,
2877 .flags = flags
2878 };
2879
2880#ifdef CONFIG_BPF_SYSCALL
2881 struct sock *sk = sock->sk;
2882 const struct proto *prot = READ_ONCE(sk->sk_prot);
2883
2884 if (prot != &unix_stream_proto)
2885 return prot->recvmsg(sk, msg, size, flags, NULL);
2886#endif
2887 return unix_stream_read_generic(&state, true);
2888}
2889
2890static int unix_stream_splice_actor(struct sk_buff *skb,
2891 int skip, int chunk,
2892 struct unix_stream_read_state *state)
2893{
2894 return skb_splice_bits(skb, state->socket->sk,
2895 UNIXCB(skb).consumed + skip,
2896 state->pipe, chunk, state->splice_flags);
2897}
2898
2899static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2900 struct pipe_inode_info *pipe,
2901 size_t size, unsigned int flags)
2902{
2903 struct unix_stream_read_state state = {
2904 .recv_actor = unix_stream_splice_actor,
2905 .socket = sock,
2906 .pipe = pipe,
2907 .size = size,
2908 .splice_flags = flags,
2909 };
2910
2911 if (unlikely(*ppos))
2912 return -ESPIPE;
2913
2914 if (sock->file->f_flags & O_NONBLOCK ||
2915 flags & SPLICE_F_NONBLOCK)
2916 state.flags = MSG_DONTWAIT;
2917
2918 return unix_stream_read_generic(&state, false);
2919}
2920
2921static int unix_shutdown(struct socket *sock, int mode)
2922{
2923 struct sock *sk = sock->sk;
2924 struct sock *other;
2925
2926 if (mode < SHUT_RD || mode > SHUT_RDWR)
2927 return -EINVAL;
2928 /* This maps:
2929 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2930 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2931 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2932 */
2933 ++mode;
2934
2935 unix_state_lock(sk);
2936 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | mode);
2937 other = unix_peer(sk);
2938 if (other)
2939 sock_hold(other);
2940 unix_state_unlock(sk);
2941 sk->sk_state_change(sk);
2942
2943 if (other &&
2944 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2945
2946 int peer_mode = 0;
2947 const struct proto *prot = READ_ONCE(other->sk_prot);
2948
2949 if (prot->unhash)
2950 prot->unhash(other);
2951 if (mode&RCV_SHUTDOWN)
2952 peer_mode |= SEND_SHUTDOWN;
2953 if (mode&SEND_SHUTDOWN)
2954 peer_mode |= RCV_SHUTDOWN;
2955 unix_state_lock(other);
2956 WRITE_ONCE(other->sk_shutdown, other->sk_shutdown | peer_mode);
2957 unix_state_unlock(other);
2958 other->sk_state_change(other);
2959 if (peer_mode == SHUTDOWN_MASK)
2960 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2961 else if (peer_mode & RCV_SHUTDOWN)
2962 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2963 }
2964 if (other)
2965 sock_put(other);
2966
2967 return 0;
2968}
2969
2970long unix_inq_len(struct sock *sk)
2971{
2972 struct sk_buff *skb;
2973 long amount = 0;
2974
2975 if (sk->sk_state == TCP_LISTEN)
2976 return -EINVAL;
2977
2978 spin_lock(&sk->sk_receive_queue.lock);
2979 if (sk->sk_type == SOCK_STREAM ||
2980 sk->sk_type == SOCK_SEQPACKET) {
2981 skb_queue_walk(&sk->sk_receive_queue, skb)
2982 amount += unix_skb_len(skb);
2983 } else {
2984 skb = skb_peek(&sk->sk_receive_queue);
2985 if (skb)
2986 amount = skb->len;
2987 }
2988 spin_unlock(&sk->sk_receive_queue.lock);
2989
2990 return amount;
2991}
2992EXPORT_SYMBOL_GPL(unix_inq_len);
2993
2994long unix_outq_len(struct sock *sk)
2995{
2996 return sk_wmem_alloc_get(sk);
2997}
2998EXPORT_SYMBOL_GPL(unix_outq_len);
2999
3000static int unix_open_file(struct sock *sk)
3001{
3002 struct path path;
3003 struct file *f;
3004 int fd;
3005
3006 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
3007 return -EPERM;
3008
3009 if (!smp_load_acquire(&unix_sk(sk)->addr))
3010 return -ENOENT;
3011
3012 path = unix_sk(sk)->path;
3013 if (!path.dentry)
3014 return -ENOENT;
3015
3016 path_get(&path);
3017
3018 fd = get_unused_fd_flags(O_CLOEXEC);
3019 if (fd < 0)
3020 goto out;
3021
3022 f = dentry_open(&path, O_PATH, current_cred());
3023 if (IS_ERR(f)) {
3024 put_unused_fd(fd);
3025 fd = PTR_ERR(f);
3026 goto out;
3027 }
3028
3029 fd_install(fd, f);
3030out:
3031 path_put(&path);
3032
3033 return fd;
3034}
3035
3036static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
3037{
3038 struct sock *sk = sock->sk;
3039 long amount = 0;
3040 int err;
3041
3042 switch (cmd) {
3043 case SIOCOUTQ:
3044 amount = unix_outq_len(sk);
3045 err = put_user(amount, (int __user *)arg);
3046 break;
3047 case SIOCINQ:
3048 amount = unix_inq_len(sk);
3049 if (amount < 0)
3050 err = amount;
3051 else
3052 err = put_user(amount, (int __user *)arg);
3053 break;
3054 case SIOCUNIXFILE:
3055 err = unix_open_file(sk);
3056 break;
3057#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
3058 case SIOCATMARK:
3059 {
3060 struct sk_buff *skb;
3061 int answ = 0;
3062
3063 skb = skb_peek(&sk->sk_receive_queue);
3064 if (skb && skb == READ_ONCE(unix_sk(sk)->oob_skb))
3065 answ = 1;
3066 err = put_user(answ, (int __user *)arg);
3067 }
3068 break;
3069#endif
3070 default:
3071 err = -ENOIOCTLCMD;
3072 break;
3073 }
3074 return err;
3075}
3076
3077#ifdef CONFIG_COMPAT
3078static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
3079{
3080 return unix_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
3081}
3082#endif
3083
3084static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait)
3085{
3086 struct sock *sk = sock->sk;
3087 __poll_t mask;
3088 u8 shutdown;
3089
3090 sock_poll_wait(file, sock, wait);
3091 mask = 0;
3092 shutdown = READ_ONCE(sk->sk_shutdown);
3093
3094 /* exceptional events? */
3095 if (READ_ONCE(sk->sk_err))
3096 mask |= EPOLLERR;
3097 if (shutdown == SHUTDOWN_MASK)
3098 mask |= EPOLLHUP;
3099 if (shutdown & RCV_SHUTDOWN)
3100 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
3101
3102 /* readable? */
3103 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
3104 mask |= EPOLLIN | EPOLLRDNORM;
3105 if (sk_is_readable(sk))
3106 mask |= EPOLLIN | EPOLLRDNORM;
3107#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
3108 if (READ_ONCE(unix_sk(sk)->oob_skb))
3109 mask |= EPOLLPRI;
3110#endif
3111
3112 /* Connection-based need to check for termination and startup */
3113 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
3114 sk->sk_state == TCP_CLOSE)
3115 mask |= EPOLLHUP;
3116
3117 /*
3118 * we set writable also when the other side has shut down the
3119 * connection. This prevents stuck sockets.
3120 */
3121 if (unix_writable(sk))
3122 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
3123
3124 return mask;
3125}
3126
3127static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
3128 poll_table *wait)
3129{
3130 struct sock *sk = sock->sk, *other;
3131 unsigned int writable;
3132 __poll_t mask;
3133 u8 shutdown;
3134
3135 sock_poll_wait(file, sock, wait);
3136 mask = 0;
3137 shutdown = READ_ONCE(sk->sk_shutdown);
3138
3139 /* exceptional events? */
3140 if (READ_ONCE(sk->sk_err) ||
3141 !skb_queue_empty_lockless(&sk->sk_error_queue))
3142 mask |= EPOLLERR |
3143 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
3144
3145 if (shutdown & RCV_SHUTDOWN)
3146 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
3147 if (shutdown == SHUTDOWN_MASK)
3148 mask |= EPOLLHUP;
3149
3150 /* readable? */
3151 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
3152 mask |= EPOLLIN | EPOLLRDNORM;
3153 if (sk_is_readable(sk))
3154 mask |= EPOLLIN | EPOLLRDNORM;
3155
3156 /* Connection-based need to check for termination and startup */
3157 if (sk->sk_type == SOCK_SEQPACKET) {
3158 if (sk->sk_state == TCP_CLOSE)
3159 mask |= EPOLLHUP;
3160 /* connection hasn't started yet? */
3161 if (sk->sk_state == TCP_SYN_SENT)
3162 return mask;
3163 }
3164
3165 /* No write status requested, avoid expensive OUT tests. */
3166 if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT)))
3167 return mask;
3168
3169 writable = unix_writable(sk);
3170 if (writable) {
3171 unix_state_lock(sk);
3172
3173 other = unix_peer(sk);
3174 if (other && unix_peer(other) != sk &&
3175 unix_recvq_full_lockless(other) &&
3176 unix_dgram_peer_wake_me(sk, other))
3177 writable = 0;
3178
3179 unix_state_unlock(sk);
3180 }
3181
3182 if (writable)
3183 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
3184 else
3185 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
3186
3187 return mask;
3188}
3189
3190#ifdef CONFIG_PROC_FS
3191
3192#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
3193
3194#define get_bucket(x) ((x) >> BUCKET_SPACE)
3195#define get_offset(x) ((x) & ((1UL << BUCKET_SPACE) - 1))
3196#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
3197
3198static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
3199{
3200 unsigned long offset = get_offset(*pos);
3201 unsigned long bucket = get_bucket(*pos);
3202 unsigned long count = 0;
3203 struct sock *sk;
3204
3205 for (sk = sk_head(&seq_file_net(seq)->unx.table.buckets[bucket]);
3206 sk; sk = sk_next(sk)) {
3207 if (++count == offset)
3208 break;
3209 }
3210
3211 return sk;
3212}
3213
3214static struct sock *unix_get_first(struct seq_file *seq, loff_t *pos)
3215{
3216 unsigned long bucket = get_bucket(*pos);
3217 struct net *net = seq_file_net(seq);
3218 struct sock *sk;
3219
3220 while (bucket < UNIX_HASH_SIZE) {
3221 spin_lock(&net->unx.table.locks[bucket]);
3222
3223 sk = unix_from_bucket(seq, pos);
3224 if (sk)
3225 return sk;
3226
3227 spin_unlock(&net->unx.table.locks[bucket]);
3228
3229 *pos = set_bucket_offset(++bucket, 1);
3230 }
3231
3232 return NULL;
3233}
3234
3235static struct sock *unix_get_next(struct seq_file *seq, struct sock *sk,
3236 loff_t *pos)
3237{
3238 unsigned long bucket = get_bucket(*pos);
3239
3240 sk = sk_next(sk);
3241 if (sk)
3242 return sk;
3243
3244
3245 spin_unlock(&seq_file_net(seq)->unx.table.locks[bucket]);
3246
3247 *pos = set_bucket_offset(++bucket, 1);
3248
3249 return unix_get_first(seq, pos);
3250}
3251
3252static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
3253{
3254 if (!*pos)
3255 return SEQ_START_TOKEN;
3256
3257 return unix_get_first(seq, pos);
3258}
3259
3260static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3261{
3262 ++*pos;
3263
3264 if (v == SEQ_START_TOKEN)
3265 return unix_get_first(seq, pos);
3266
3267 return unix_get_next(seq, v, pos);
3268}
3269
3270static void unix_seq_stop(struct seq_file *seq, void *v)
3271{
3272 struct sock *sk = v;
3273
3274 if (sk)
3275 spin_unlock(&seq_file_net(seq)->unx.table.locks[sk->sk_hash]);
3276}
3277
3278static int unix_seq_show(struct seq_file *seq, void *v)
3279{
3280
3281 if (v == SEQ_START_TOKEN)
3282 seq_puts(seq, "Num RefCount Protocol Flags Type St "
3283 "Inode Path\n");
3284 else {
3285 struct sock *s = v;
3286 struct unix_sock *u = unix_sk(s);
3287 unix_state_lock(s);
3288
3289 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
3290 s,
3291 refcount_read(&s->sk_refcnt),
3292 0,
3293 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
3294 s->sk_type,
3295 s->sk_socket ?
3296 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
3297 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
3298 sock_i_ino(s));
3299
3300 if (u->addr) { // under a hash table lock here
3301 int i, len;
3302 seq_putc(seq, ' ');
3303
3304 i = 0;
3305 len = u->addr->len -
3306 offsetof(struct sockaddr_un, sun_path);
3307 if (u->addr->name->sun_path[0]) {
3308 len--;
3309 } else {
3310 seq_putc(seq, '@');
3311 i++;
3312 }
3313 for ( ; i < len; i++)
3314 seq_putc(seq, u->addr->name->sun_path[i] ?:
3315 '@');
3316 }
3317 unix_state_unlock(s);
3318 seq_putc(seq, '\n');
3319 }
3320
3321 return 0;
3322}
3323
3324static const struct seq_operations unix_seq_ops = {
3325 .start = unix_seq_start,
3326 .next = unix_seq_next,
3327 .stop = unix_seq_stop,
3328 .show = unix_seq_show,
3329};
3330
3331#ifdef CONFIG_BPF_SYSCALL
3332struct bpf_unix_iter_state {
3333 struct seq_net_private p;
3334 unsigned int cur_sk;
3335 unsigned int end_sk;
3336 unsigned int max_sk;
3337 struct sock **batch;
3338 bool st_bucket_done;
3339};
3340
3341struct bpf_iter__unix {
3342 __bpf_md_ptr(struct bpf_iter_meta *, meta);
3343 __bpf_md_ptr(struct unix_sock *, unix_sk);
3344 uid_t uid __aligned(8);
3345};
3346
3347static int unix_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
3348 struct unix_sock *unix_sk, uid_t uid)
3349{
3350 struct bpf_iter__unix ctx;
3351
3352 meta->seq_num--; /* skip SEQ_START_TOKEN */
3353 ctx.meta = meta;
3354 ctx.unix_sk = unix_sk;
3355 ctx.uid = uid;
3356 return bpf_iter_run_prog(prog, &ctx);
3357}
3358
3359static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk)
3360
3361{
3362 struct bpf_unix_iter_state *iter = seq->private;
3363 unsigned int expected = 1;
3364 struct sock *sk;
3365
3366 sock_hold(start_sk);
3367 iter->batch[iter->end_sk++] = start_sk;
3368
3369 for (sk = sk_next(start_sk); sk; sk = sk_next(sk)) {
3370 if (iter->end_sk < iter->max_sk) {
3371 sock_hold(sk);
3372 iter->batch[iter->end_sk++] = sk;
3373 }
3374
3375 expected++;
3376 }
3377
3378 spin_unlock(&seq_file_net(seq)->unx.table.locks[start_sk->sk_hash]);
3379
3380 return expected;
3381}
3382
3383static void bpf_iter_unix_put_batch(struct bpf_unix_iter_state *iter)
3384{
3385 while (iter->cur_sk < iter->end_sk)
3386 sock_put(iter->batch[iter->cur_sk++]);
3387}
3388
3389static int bpf_iter_unix_realloc_batch(struct bpf_unix_iter_state *iter,
3390 unsigned int new_batch_sz)
3391{
3392 struct sock **new_batch;
3393
3394 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3395 GFP_USER | __GFP_NOWARN);
3396 if (!new_batch)
3397 return -ENOMEM;
3398
3399 bpf_iter_unix_put_batch(iter);
3400 kvfree(iter->batch);
3401 iter->batch = new_batch;
3402 iter->max_sk = new_batch_sz;
3403
3404 return 0;
3405}
3406
3407static struct sock *bpf_iter_unix_batch(struct seq_file *seq,
3408 loff_t *pos)
3409{
3410 struct bpf_unix_iter_state *iter = seq->private;
3411 unsigned int expected;
3412 bool resized = false;
3413 struct sock *sk;
3414
3415 if (iter->st_bucket_done)
3416 *pos = set_bucket_offset(get_bucket(*pos) + 1, 1);
3417
3418again:
3419 /* Get a new batch */
3420 iter->cur_sk = 0;
3421 iter->end_sk = 0;
3422
3423 sk = unix_get_first(seq, pos);
3424 if (!sk)
3425 return NULL; /* Done */
3426
3427 expected = bpf_iter_unix_hold_batch(seq, sk);
3428
3429 if (iter->end_sk == expected) {
3430 iter->st_bucket_done = true;
3431 return sk;
3432 }
3433
3434 if (!resized && !bpf_iter_unix_realloc_batch(iter, expected * 3 / 2)) {
3435 resized = true;
3436 goto again;
3437 }
3438
3439 return sk;
3440}
3441
3442static void *bpf_iter_unix_seq_start(struct seq_file *seq, loff_t *pos)
3443{
3444 if (!*pos)
3445 return SEQ_START_TOKEN;
3446
3447 /* bpf iter does not support lseek, so it always
3448 * continue from where it was stop()-ped.
3449 */
3450 return bpf_iter_unix_batch(seq, pos);
3451}
3452
3453static void *bpf_iter_unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3454{
3455 struct bpf_unix_iter_state *iter = seq->private;
3456 struct sock *sk;
3457
3458 /* Whenever seq_next() is called, the iter->cur_sk is
3459 * done with seq_show(), so advance to the next sk in
3460 * the batch.
3461 */
3462 if (iter->cur_sk < iter->end_sk)
3463 sock_put(iter->batch[iter->cur_sk++]);
3464
3465 ++*pos;
3466
3467 if (iter->cur_sk < iter->end_sk)
3468 sk = iter->batch[iter->cur_sk];
3469 else
3470 sk = bpf_iter_unix_batch(seq, pos);
3471
3472 return sk;
3473}
3474
3475static int bpf_iter_unix_seq_show(struct seq_file *seq, void *v)
3476{
3477 struct bpf_iter_meta meta;
3478 struct bpf_prog *prog;
3479 struct sock *sk = v;
3480 uid_t uid;
3481 bool slow;
3482 int ret;
3483
3484 if (v == SEQ_START_TOKEN)
3485 return 0;
3486
3487 slow = lock_sock_fast(sk);
3488
3489 if (unlikely(sk_unhashed(sk))) {
3490 ret = SEQ_SKIP;
3491 goto unlock;
3492 }
3493
3494 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3495 meta.seq = seq;
3496 prog = bpf_iter_get_info(&meta, false);
3497 ret = unix_prog_seq_show(prog, &meta, v, uid);
3498unlock:
3499 unlock_sock_fast(sk, slow);
3500 return ret;
3501}
3502
3503static void bpf_iter_unix_seq_stop(struct seq_file *seq, void *v)
3504{
3505 struct bpf_unix_iter_state *iter = seq->private;
3506 struct bpf_iter_meta meta;
3507 struct bpf_prog *prog;
3508
3509 if (!v) {
3510 meta.seq = seq;
3511 prog = bpf_iter_get_info(&meta, true);
3512 if (prog)
3513 (void)unix_prog_seq_show(prog, &meta, v, 0);
3514 }
3515
3516 if (iter->cur_sk < iter->end_sk)
3517 bpf_iter_unix_put_batch(iter);
3518}
3519
3520static const struct seq_operations bpf_iter_unix_seq_ops = {
3521 .start = bpf_iter_unix_seq_start,
3522 .next = bpf_iter_unix_seq_next,
3523 .stop = bpf_iter_unix_seq_stop,
3524 .show = bpf_iter_unix_seq_show,
3525};
3526#endif
3527#endif
3528
3529static const struct net_proto_family unix_family_ops = {
3530 .family = PF_UNIX,
3531 .create = unix_create,
3532 .owner = THIS_MODULE,
3533};
3534
3535
3536static int __net_init unix_net_init(struct net *net)
3537{
3538 int i;
3539
3540 net->unx.sysctl_max_dgram_qlen = 10;
3541 if (unix_sysctl_register(net))
3542 goto out;
3543
3544#ifdef CONFIG_PROC_FS
3545 if (!proc_create_net("unix", 0, net->proc_net, &unix_seq_ops,
3546 sizeof(struct seq_net_private)))
3547 goto err_sysctl;
3548#endif
3549
3550 net->unx.table.locks = kvmalloc_array(UNIX_HASH_SIZE,
3551 sizeof(spinlock_t), GFP_KERNEL);
3552 if (!net->unx.table.locks)
3553 goto err_proc;
3554
3555 net->unx.table.buckets = kvmalloc_array(UNIX_HASH_SIZE,
3556 sizeof(struct hlist_head),
3557 GFP_KERNEL);
3558 if (!net->unx.table.buckets)
3559 goto free_locks;
3560
3561 for (i = 0; i < UNIX_HASH_SIZE; i++) {
3562 spin_lock_init(&net->unx.table.locks[i]);
3563 INIT_HLIST_HEAD(&net->unx.table.buckets[i]);
3564 }
3565
3566 return 0;
3567
3568free_locks:
3569 kvfree(net->unx.table.locks);
3570err_proc:
3571#ifdef CONFIG_PROC_FS
3572 remove_proc_entry("unix", net->proc_net);
3573err_sysctl:
3574#endif
3575 unix_sysctl_unregister(net);
3576out:
3577 return -ENOMEM;
3578}
3579
3580static void __net_exit unix_net_exit(struct net *net)
3581{
3582 kvfree(net->unx.table.buckets);
3583 kvfree(net->unx.table.locks);
3584 unix_sysctl_unregister(net);
3585 remove_proc_entry("unix", net->proc_net);
3586}
3587
3588static struct pernet_operations unix_net_ops = {
3589 .init = unix_net_init,
3590 .exit = unix_net_exit,
3591};
3592
3593#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3594DEFINE_BPF_ITER_FUNC(unix, struct bpf_iter_meta *meta,
3595 struct unix_sock *unix_sk, uid_t uid)
3596
3597#define INIT_BATCH_SZ 16
3598
3599static int bpf_iter_init_unix(void *priv_data, struct bpf_iter_aux_info *aux)
3600{
3601 struct bpf_unix_iter_state *iter = priv_data;
3602 int err;
3603
3604 err = bpf_iter_init_seq_net(priv_data, aux);
3605 if (err)
3606 return err;
3607
3608 err = bpf_iter_unix_realloc_batch(iter, INIT_BATCH_SZ);
3609 if (err) {
3610 bpf_iter_fini_seq_net(priv_data);
3611 return err;
3612 }
3613
3614 return 0;
3615}
3616
3617static void bpf_iter_fini_unix(void *priv_data)
3618{
3619 struct bpf_unix_iter_state *iter = priv_data;
3620
3621 bpf_iter_fini_seq_net(priv_data);
3622 kvfree(iter->batch);
3623}
3624
3625static const struct bpf_iter_seq_info unix_seq_info = {
3626 .seq_ops = &bpf_iter_unix_seq_ops,
3627 .init_seq_private = bpf_iter_init_unix,
3628 .fini_seq_private = bpf_iter_fini_unix,
3629 .seq_priv_size = sizeof(struct bpf_unix_iter_state),
3630};
3631
3632static const struct bpf_func_proto *
3633bpf_iter_unix_get_func_proto(enum bpf_func_id func_id,
3634 const struct bpf_prog *prog)
3635{
3636 switch (func_id) {
3637 case BPF_FUNC_setsockopt:
3638 return &bpf_sk_setsockopt_proto;
3639 case BPF_FUNC_getsockopt:
3640 return &bpf_sk_getsockopt_proto;
3641 default:
3642 return NULL;
3643 }
3644}
3645
3646static struct bpf_iter_reg unix_reg_info = {
3647 .target = "unix",
3648 .ctx_arg_info_size = 1,
3649 .ctx_arg_info = {
3650 { offsetof(struct bpf_iter__unix, unix_sk),
3651 PTR_TO_BTF_ID_OR_NULL },
3652 },
3653 .get_func_proto = bpf_iter_unix_get_func_proto,
3654 .seq_info = &unix_seq_info,
3655};
3656
3657static void __init bpf_iter_register(void)
3658{
3659 unix_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UNIX];
3660 if (bpf_iter_reg_target(&unix_reg_info))
3661 pr_warn("Warning: could not register bpf iterator unix\n");
3662}
3663#endif
3664
3665static int __init af_unix_init(void)
3666{
3667 int i, rc = -1;
3668
3669 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb));
3670
3671 for (i = 0; i < UNIX_HASH_SIZE / 2; i++) {
3672 spin_lock_init(&bsd_socket_locks[i]);
3673 INIT_HLIST_HEAD(&bsd_socket_buckets[i]);
3674 }
3675
3676 rc = proto_register(&unix_dgram_proto, 1);
3677 if (rc != 0) {
3678 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
3679 goto out;
3680 }
3681
3682 rc = proto_register(&unix_stream_proto, 1);
3683 if (rc != 0) {
3684 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
3685 proto_unregister(&unix_dgram_proto);
3686 goto out;
3687 }
3688
3689 sock_register(&unix_family_ops);
3690 register_pernet_subsys(&unix_net_ops);
3691 unix_bpf_build_proto();
3692
3693#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3694 bpf_iter_register();
3695#endif
3696
3697out:
3698 return rc;
3699}
3700
3701/* Later than subsys_initcall() because we depend on stuff initialised there */
3702fs_initcall(af_unix_init);
1/*
2 * NET4: Implementation of BSD Unix domain sockets.
3 *
4 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * Fixes:
12 * Linus Torvalds : Assorted bug cures.
13 * Niibe Yutaka : async I/O support.
14 * Carsten Paeth : PF_UNIX check, address fixes.
15 * Alan Cox : Limit size of allocated blocks.
16 * Alan Cox : Fixed the stupid socketpair bug.
17 * Alan Cox : BSD compatibility fine tuning.
18 * Alan Cox : Fixed a bug in connect when interrupted.
19 * Alan Cox : Sorted out a proper draft version of
20 * file descriptor passing hacked up from
21 * Mike Shaver's work.
22 * Marty Leisner : Fixes to fd passing
23 * Nick Nevin : recvmsg bugfix.
24 * Alan Cox : Started proper garbage collector
25 * Heiko EiBfeldt : Missing verify_area check
26 * Alan Cox : Started POSIXisms
27 * Andreas Schwab : Replace inode by dentry for proper
28 * reference counting
29 * Kirk Petersen : Made this a module
30 * Christoph Rohland : Elegant non-blocking accept/connect algorithm.
31 * Lots of bug fixes.
32 * Alexey Kuznetosv : Repaired (I hope) bugs introduces
33 * by above two patches.
34 * Andrea Arcangeli : If possible we block in connect(2)
35 * if the max backlog of the listen socket
36 * is been reached. This won't break
37 * old apps and it will avoid huge amount
38 * of socks hashed (this for unix_gc()
39 * performances reasons).
40 * Security fix that limits the max
41 * number of socks to 2*max_files and
42 * the number of skb queueable in the
43 * dgram receiver.
44 * Artur Skawina : Hash function optimizations
45 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
46 * Malcolm Beattie : Set peercred for socketpair
47 * Michal Ostrowski : Module initialization cleanup.
48 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT,
49 * the core infrastructure is doing that
50 * for all net proto families now (2.5.69+)
51 *
52 *
53 * Known differences from reference BSD that was tested:
54 *
55 * [TO FIX]
56 * ECONNREFUSED is not returned from one end of a connected() socket to the
57 * other the moment one end closes.
58 * fstat() doesn't return st_dev=0, and give the blksize as high water mark
59 * and a fake inode identifier (nor the BSD first socket fstat twice bug).
60 * [NOT TO FIX]
61 * accept() returns a path name even if the connecting socket has closed
62 * in the meantime (BSD loses the path and gives up).
63 * accept() returns 0 length path for an unbound connector. BSD returns 16
64 * and a null first byte in the path (but not for gethost/peername - BSD bug ??)
65 * socketpair(...SOCK_RAW..) doesn't panic the kernel.
66 * BSD af_unix apparently has connect forgetting to block properly.
67 * (need to check this with the POSIX spec in detail)
68 *
69 * Differences from 2.0.0-11-... (ANK)
70 * Bug fixes and improvements.
71 * - client shutdown killed server socket.
72 * - removed all useless cli/sti pairs.
73 *
74 * Semantic changes/extensions.
75 * - generic control message passing.
76 * - SCM_CREDENTIALS control message.
77 * - "Abstract" (not FS based) socket bindings.
78 * Abstract names are sequences of bytes (not zero terminated)
79 * started by 0, so that this name space does not intersect
80 * with BSD names.
81 */
82
83#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
84
85#include <linux/module.h>
86#include <linux/kernel.h>
87#include <linux/signal.h>
88#include <linux/sched/signal.h>
89#include <linux/errno.h>
90#include <linux/string.h>
91#include <linux/stat.h>
92#include <linux/dcache.h>
93#include <linux/namei.h>
94#include <linux/socket.h>
95#include <linux/un.h>
96#include <linux/fcntl.h>
97#include <linux/termios.h>
98#include <linux/sockios.h>
99#include <linux/net.h>
100#include <linux/in.h>
101#include <linux/fs.h>
102#include <linux/slab.h>
103#include <linux/uaccess.h>
104#include <linux/skbuff.h>
105#include <linux/netdevice.h>
106#include <net/net_namespace.h>
107#include <net/sock.h>
108#include <net/tcp_states.h>
109#include <net/af_unix.h>
110#include <linux/proc_fs.h>
111#include <linux/seq_file.h>
112#include <net/scm.h>
113#include <linux/init.h>
114#include <linux/poll.h>
115#include <linux/rtnetlink.h>
116#include <linux/mount.h>
117#include <net/checksum.h>
118#include <linux/security.h>
119#include <linux/freezer.h>
120#include <linux/file.h>
121
122struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
123EXPORT_SYMBOL_GPL(unix_socket_table);
124DEFINE_SPINLOCK(unix_table_lock);
125EXPORT_SYMBOL_GPL(unix_table_lock);
126static atomic_long_t unix_nr_socks;
127
128
129static struct hlist_head *unix_sockets_unbound(void *addr)
130{
131 unsigned long hash = (unsigned long)addr;
132
133 hash ^= hash >> 16;
134 hash ^= hash >> 8;
135 hash %= UNIX_HASH_SIZE;
136 return &unix_socket_table[UNIX_HASH_SIZE + hash];
137}
138
139#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
140
141#ifdef CONFIG_SECURITY_NETWORK
142static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
143{
144 UNIXCB(skb).secid = scm->secid;
145}
146
147static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
148{
149 scm->secid = UNIXCB(skb).secid;
150}
151
152static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
153{
154 return (scm->secid == UNIXCB(skb).secid);
155}
156#else
157static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
158{ }
159
160static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
161{ }
162
163static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
164{
165 return true;
166}
167#endif /* CONFIG_SECURITY_NETWORK */
168
169/*
170 * SMP locking strategy:
171 * hash table is protected with spinlock unix_table_lock
172 * each socket state is protected by separate spin lock.
173 */
174
175static inline unsigned int unix_hash_fold(__wsum n)
176{
177 unsigned int hash = (__force unsigned int)csum_fold(n);
178
179 hash ^= hash>>8;
180 return hash&(UNIX_HASH_SIZE-1);
181}
182
183#define unix_peer(sk) (unix_sk(sk)->peer)
184
185static inline int unix_our_peer(struct sock *sk, struct sock *osk)
186{
187 return unix_peer(osk) == sk;
188}
189
190static inline int unix_may_send(struct sock *sk, struct sock *osk)
191{
192 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
193}
194
195static inline int unix_recvq_full(struct sock const *sk)
196{
197 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
198}
199
200struct sock *unix_peer_get(struct sock *s)
201{
202 struct sock *peer;
203
204 unix_state_lock(s);
205 peer = unix_peer(s);
206 if (peer)
207 sock_hold(peer);
208 unix_state_unlock(s);
209 return peer;
210}
211EXPORT_SYMBOL_GPL(unix_peer_get);
212
213static inline void unix_release_addr(struct unix_address *addr)
214{
215 if (refcount_dec_and_test(&addr->refcnt))
216 kfree(addr);
217}
218
219/*
220 * Check unix socket name:
221 * - should be not zero length.
222 * - if started by not zero, should be NULL terminated (FS object)
223 * - if started by zero, it is abstract name.
224 */
225
226static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
227{
228 if (len <= sizeof(short) || len > sizeof(*sunaddr))
229 return -EINVAL;
230 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
231 return -EINVAL;
232 if (sunaddr->sun_path[0]) {
233 /*
234 * This may look like an off by one error but it is a bit more
235 * subtle. 108 is the longest valid AF_UNIX path for a binding.
236 * sun_path[108] doesn't as such exist. However in kernel space
237 * we are guaranteed that it is a valid memory location in our
238 * kernel address buffer.
239 */
240 ((char *)sunaddr)[len] = 0;
241 len = strlen(sunaddr->sun_path)+1+sizeof(short);
242 return len;
243 }
244
245 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
246 return len;
247}
248
249static void __unix_remove_socket(struct sock *sk)
250{
251 sk_del_node_init(sk);
252}
253
254static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
255{
256 WARN_ON(!sk_unhashed(sk));
257 sk_add_node(sk, list);
258}
259
260static inline void unix_remove_socket(struct sock *sk)
261{
262 spin_lock(&unix_table_lock);
263 __unix_remove_socket(sk);
264 spin_unlock(&unix_table_lock);
265}
266
267static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
268{
269 spin_lock(&unix_table_lock);
270 __unix_insert_socket(list, sk);
271 spin_unlock(&unix_table_lock);
272}
273
274static struct sock *__unix_find_socket_byname(struct net *net,
275 struct sockaddr_un *sunname,
276 int len, int type, unsigned int hash)
277{
278 struct sock *s;
279
280 sk_for_each(s, &unix_socket_table[hash ^ type]) {
281 struct unix_sock *u = unix_sk(s);
282
283 if (!net_eq(sock_net(s), net))
284 continue;
285
286 if (u->addr->len == len &&
287 !memcmp(u->addr->name, sunname, len))
288 goto found;
289 }
290 s = NULL;
291found:
292 return s;
293}
294
295static inline struct sock *unix_find_socket_byname(struct net *net,
296 struct sockaddr_un *sunname,
297 int len, int type,
298 unsigned int hash)
299{
300 struct sock *s;
301
302 spin_lock(&unix_table_lock);
303 s = __unix_find_socket_byname(net, sunname, len, type, hash);
304 if (s)
305 sock_hold(s);
306 spin_unlock(&unix_table_lock);
307 return s;
308}
309
310static struct sock *unix_find_socket_byinode(struct inode *i)
311{
312 struct sock *s;
313
314 spin_lock(&unix_table_lock);
315 sk_for_each(s,
316 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
317 struct dentry *dentry = unix_sk(s)->path.dentry;
318
319 if (dentry && d_backing_inode(dentry) == i) {
320 sock_hold(s);
321 goto found;
322 }
323 }
324 s = NULL;
325found:
326 spin_unlock(&unix_table_lock);
327 return s;
328}
329
330/* Support code for asymmetrically connected dgram sockets
331 *
332 * If a datagram socket is connected to a socket not itself connected
333 * to the first socket (eg, /dev/log), clients may only enqueue more
334 * messages if the present receive queue of the server socket is not
335 * "too large". This means there's a second writeability condition
336 * poll and sendmsg need to test. The dgram recv code will do a wake
337 * up on the peer_wait wait queue of a socket upon reception of a
338 * datagram which needs to be propagated to sleeping would-be writers
339 * since these might not have sent anything so far. This can't be
340 * accomplished via poll_wait because the lifetime of the server
341 * socket might be less than that of its clients if these break their
342 * association with it or if the server socket is closed while clients
343 * are still connected to it and there's no way to inform "a polling
344 * implementation" that it should let go of a certain wait queue
345 *
346 * In order to propagate a wake up, a wait_queue_entry_t of the client
347 * socket is enqueued on the peer_wait queue of the server socket
348 * whose wake function does a wake_up on the ordinary client socket
349 * wait queue. This connection is established whenever a write (or
350 * poll for write) hit the flow control condition and broken when the
351 * association to the server socket is dissolved or after a wake up
352 * was relayed.
353 */
354
355static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
356 void *key)
357{
358 struct unix_sock *u;
359 wait_queue_head_t *u_sleep;
360
361 u = container_of(q, struct unix_sock, peer_wake);
362
363 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
364 q);
365 u->peer_wake.private = NULL;
366
367 /* relaying can only happen while the wq still exists */
368 u_sleep = sk_sleep(&u->sk);
369 if (u_sleep)
370 wake_up_interruptible_poll(u_sleep, key_to_poll(key));
371
372 return 0;
373}
374
375static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
376{
377 struct unix_sock *u, *u_other;
378 int rc;
379
380 u = unix_sk(sk);
381 u_other = unix_sk(other);
382 rc = 0;
383 spin_lock(&u_other->peer_wait.lock);
384
385 if (!u->peer_wake.private) {
386 u->peer_wake.private = other;
387 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
388
389 rc = 1;
390 }
391
392 spin_unlock(&u_other->peer_wait.lock);
393 return rc;
394}
395
396static void unix_dgram_peer_wake_disconnect(struct sock *sk,
397 struct sock *other)
398{
399 struct unix_sock *u, *u_other;
400
401 u = unix_sk(sk);
402 u_other = unix_sk(other);
403 spin_lock(&u_other->peer_wait.lock);
404
405 if (u->peer_wake.private == other) {
406 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
407 u->peer_wake.private = NULL;
408 }
409
410 spin_unlock(&u_other->peer_wait.lock);
411}
412
413static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
414 struct sock *other)
415{
416 unix_dgram_peer_wake_disconnect(sk, other);
417 wake_up_interruptible_poll(sk_sleep(sk),
418 EPOLLOUT |
419 EPOLLWRNORM |
420 EPOLLWRBAND);
421}
422
423/* preconditions:
424 * - unix_peer(sk) == other
425 * - association is stable
426 */
427static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
428{
429 int connected;
430
431 connected = unix_dgram_peer_wake_connect(sk, other);
432
433 if (unix_recvq_full(other))
434 return 1;
435
436 if (connected)
437 unix_dgram_peer_wake_disconnect(sk, other);
438
439 return 0;
440}
441
442static int unix_writable(const struct sock *sk)
443{
444 return sk->sk_state != TCP_LISTEN &&
445 (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
446}
447
448static void unix_write_space(struct sock *sk)
449{
450 struct socket_wq *wq;
451
452 rcu_read_lock();
453 if (unix_writable(sk)) {
454 wq = rcu_dereference(sk->sk_wq);
455 if (skwq_has_sleeper(wq))
456 wake_up_interruptible_sync_poll(&wq->wait,
457 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
458 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
459 }
460 rcu_read_unlock();
461}
462
463/* When dgram socket disconnects (or changes its peer), we clear its receive
464 * queue of packets arrived from previous peer. First, it allows to do
465 * flow control based only on wmem_alloc; second, sk connected to peer
466 * may receive messages only from that peer. */
467static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
468{
469 if (!skb_queue_empty(&sk->sk_receive_queue)) {
470 skb_queue_purge(&sk->sk_receive_queue);
471 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
472
473 /* If one link of bidirectional dgram pipe is disconnected,
474 * we signal error. Messages are lost. Do not make this,
475 * when peer was not connected to us.
476 */
477 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
478 other->sk_err = ECONNRESET;
479 other->sk_error_report(other);
480 }
481 }
482}
483
484static void unix_sock_destructor(struct sock *sk)
485{
486 struct unix_sock *u = unix_sk(sk);
487
488 skb_queue_purge(&sk->sk_receive_queue);
489
490 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
491 WARN_ON(!sk_unhashed(sk));
492 WARN_ON(sk->sk_socket);
493 if (!sock_flag(sk, SOCK_DEAD)) {
494 pr_info("Attempt to release alive unix socket: %p\n", sk);
495 return;
496 }
497
498 if (u->addr)
499 unix_release_addr(u->addr);
500
501 atomic_long_dec(&unix_nr_socks);
502 local_bh_disable();
503 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
504 local_bh_enable();
505#ifdef UNIX_REFCNT_DEBUG
506 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
507 atomic_long_read(&unix_nr_socks));
508#endif
509}
510
511static void unix_release_sock(struct sock *sk, int embrion)
512{
513 struct unix_sock *u = unix_sk(sk);
514 struct path path;
515 struct sock *skpair;
516 struct sk_buff *skb;
517 int state;
518
519 unix_remove_socket(sk);
520
521 /* Clear state */
522 unix_state_lock(sk);
523 sock_orphan(sk);
524 sk->sk_shutdown = SHUTDOWN_MASK;
525 path = u->path;
526 u->path.dentry = NULL;
527 u->path.mnt = NULL;
528 state = sk->sk_state;
529 sk->sk_state = TCP_CLOSE;
530 unix_state_unlock(sk);
531
532 wake_up_interruptible_all(&u->peer_wait);
533
534 skpair = unix_peer(sk);
535
536 if (skpair != NULL) {
537 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
538 unix_state_lock(skpair);
539 /* No more writes */
540 skpair->sk_shutdown = SHUTDOWN_MASK;
541 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
542 skpair->sk_err = ECONNRESET;
543 unix_state_unlock(skpair);
544 skpair->sk_state_change(skpair);
545 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
546 }
547
548 unix_dgram_peer_wake_disconnect(sk, skpair);
549 sock_put(skpair); /* It may now die */
550 unix_peer(sk) = NULL;
551 }
552
553 /* Try to flush out this socket. Throw out buffers at least */
554
555 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
556 if (state == TCP_LISTEN)
557 unix_release_sock(skb->sk, 1);
558 /* passed fds are erased in the kfree_skb hook */
559 UNIXCB(skb).consumed = skb->len;
560 kfree_skb(skb);
561 }
562
563 if (path.dentry)
564 path_put(&path);
565
566 sock_put(sk);
567
568 /* ---- Socket is dead now and most probably destroyed ---- */
569
570 /*
571 * Fixme: BSD difference: In BSD all sockets connected to us get
572 * ECONNRESET and we die on the spot. In Linux we behave
573 * like files and pipes do and wait for the last
574 * dereference.
575 *
576 * Can't we simply set sock->err?
577 *
578 * What the above comment does talk about? --ANK(980817)
579 */
580
581 if (unix_tot_inflight)
582 unix_gc(); /* Garbage collect fds */
583}
584
585static void init_peercred(struct sock *sk)
586{
587 put_pid(sk->sk_peer_pid);
588 if (sk->sk_peer_cred)
589 put_cred(sk->sk_peer_cred);
590 sk->sk_peer_pid = get_pid(task_tgid(current));
591 sk->sk_peer_cred = get_current_cred();
592}
593
594static void copy_peercred(struct sock *sk, struct sock *peersk)
595{
596 put_pid(sk->sk_peer_pid);
597 if (sk->sk_peer_cred)
598 put_cred(sk->sk_peer_cred);
599 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
600 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
601}
602
603static int unix_listen(struct socket *sock, int backlog)
604{
605 int err;
606 struct sock *sk = sock->sk;
607 struct unix_sock *u = unix_sk(sk);
608 struct pid *old_pid = NULL;
609
610 err = -EOPNOTSUPP;
611 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
612 goto out; /* Only stream/seqpacket sockets accept */
613 err = -EINVAL;
614 if (!u->addr)
615 goto out; /* No listens on an unbound socket */
616 unix_state_lock(sk);
617 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
618 goto out_unlock;
619 if (backlog > sk->sk_max_ack_backlog)
620 wake_up_interruptible_all(&u->peer_wait);
621 sk->sk_max_ack_backlog = backlog;
622 sk->sk_state = TCP_LISTEN;
623 /* set credentials so connect can copy them */
624 init_peercred(sk);
625 err = 0;
626
627out_unlock:
628 unix_state_unlock(sk);
629 put_pid(old_pid);
630out:
631 return err;
632}
633
634static int unix_release(struct socket *);
635static int unix_bind(struct socket *, struct sockaddr *, int);
636static int unix_stream_connect(struct socket *, struct sockaddr *,
637 int addr_len, int flags);
638static int unix_socketpair(struct socket *, struct socket *);
639static int unix_accept(struct socket *, struct socket *, int, bool);
640static int unix_getname(struct socket *, struct sockaddr *, int);
641static __poll_t unix_poll(struct file *, struct socket *, poll_table *);
642static __poll_t unix_dgram_poll(struct file *, struct socket *,
643 poll_table *);
644static int unix_ioctl(struct socket *, unsigned int, unsigned long);
645static int unix_shutdown(struct socket *, int);
646static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
647static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
648static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
649 size_t size, int flags);
650static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
651 struct pipe_inode_info *, size_t size,
652 unsigned int flags);
653static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
654static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
655static int unix_dgram_connect(struct socket *, struct sockaddr *,
656 int, int);
657static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
658static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
659 int);
660
661static int unix_set_peek_off(struct sock *sk, int val)
662{
663 struct unix_sock *u = unix_sk(sk);
664
665 if (mutex_lock_interruptible(&u->iolock))
666 return -EINTR;
667
668 sk->sk_peek_off = val;
669 mutex_unlock(&u->iolock);
670
671 return 0;
672}
673
674
675static const struct proto_ops unix_stream_ops = {
676 .family = PF_UNIX,
677 .owner = THIS_MODULE,
678 .release = unix_release,
679 .bind = unix_bind,
680 .connect = unix_stream_connect,
681 .socketpair = unix_socketpair,
682 .accept = unix_accept,
683 .getname = unix_getname,
684 .poll = unix_poll,
685 .ioctl = unix_ioctl,
686 .listen = unix_listen,
687 .shutdown = unix_shutdown,
688 .setsockopt = sock_no_setsockopt,
689 .getsockopt = sock_no_getsockopt,
690 .sendmsg = unix_stream_sendmsg,
691 .recvmsg = unix_stream_recvmsg,
692 .mmap = sock_no_mmap,
693 .sendpage = unix_stream_sendpage,
694 .splice_read = unix_stream_splice_read,
695 .set_peek_off = unix_set_peek_off,
696};
697
698static const struct proto_ops unix_dgram_ops = {
699 .family = PF_UNIX,
700 .owner = THIS_MODULE,
701 .release = unix_release,
702 .bind = unix_bind,
703 .connect = unix_dgram_connect,
704 .socketpair = unix_socketpair,
705 .accept = sock_no_accept,
706 .getname = unix_getname,
707 .poll = unix_dgram_poll,
708 .ioctl = unix_ioctl,
709 .listen = sock_no_listen,
710 .shutdown = unix_shutdown,
711 .setsockopt = sock_no_setsockopt,
712 .getsockopt = sock_no_getsockopt,
713 .sendmsg = unix_dgram_sendmsg,
714 .recvmsg = unix_dgram_recvmsg,
715 .mmap = sock_no_mmap,
716 .sendpage = sock_no_sendpage,
717 .set_peek_off = unix_set_peek_off,
718};
719
720static const struct proto_ops unix_seqpacket_ops = {
721 .family = PF_UNIX,
722 .owner = THIS_MODULE,
723 .release = unix_release,
724 .bind = unix_bind,
725 .connect = unix_stream_connect,
726 .socketpair = unix_socketpair,
727 .accept = unix_accept,
728 .getname = unix_getname,
729 .poll = unix_dgram_poll,
730 .ioctl = unix_ioctl,
731 .listen = unix_listen,
732 .shutdown = unix_shutdown,
733 .setsockopt = sock_no_setsockopt,
734 .getsockopt = sock_no_getsockopt,
735 .sendmsg = unix_seqpacket_sendmsg,
736 .recvmsg = unix_seqpacket_recvmsg,
737 .mmap = sock_no_mmap,
738 .sendpage = sock_no_sendpage,
739 .set_peek_off = unix_set_peek_off,
740};
741
742static struct proto unix_proto = {
743 .name = "UNIX",
744 .owner = THIS_MODULE,
745 .obj_size = sizeof(struct unix_sock),
746};
747
748static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
749{
750 struct sock *sk = NULL;
751 struct unix_sock *u;
752
753 atomic_long_inc(&unix_nr_socks);
754 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
755 goto out;
756
757 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
758 if (!sk)
759 goto out;
760
761 sock_init_data(sock, sk);
762
763 sk->sk_allocation = GFP_KERNEL_ACCOUNT;
764 sk->sk_write_space = unix_write_space;
765 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
766 sk->sk_destruct = unix_sock_destructor;
767 u = unix_sk(sk);
768 u->path.dentry = NULL;
769 u->path.mnt = NULL;
770 spin_lock_init(&u->lock);
771 atomic_long_set(&u->inflight, 0);
772 INIT_LIST_HEAD(&u->link);
773 mutex_init(&u->iolock); /* single task reading lock */
774 mutex_init(&u->bindlock); /* single task binding lock */
775 init_waitqueue_head(&u->peer_wait);
776 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
777 unix_insert_socket(unix_sockets_unbound(sk), sk);
778out:
779 if (sk == NULL)
780 atomic_long_dec(&unix_nr_socks);
781 else {
782 local_bh_disable();
783 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
784 local_bh_enable();
785 }
786 return sk;
787}
788
789static int unix_create(struct net *net, struct socket *sock, int protocol,
790 int kern)
791{
792 if (protocol && protocol != PF_UNIX)
793 return -EPROTONOSUPPORT;
794
795 sock->state = SS_UNCONNECTED;
796
797 switch (sock->type) {
798 case SOCK_STREAM:
799 sock->ops = &unix_stream_ops;
800 break;
801 /*
802 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
803 * nothing uses it.
804 */
805 case SOCK_RAW:
806 sock->type = SOCK_DGRAM;
807 /* fall through */
808 case SOCK_DGRAM:
809 sock->ops = &unix_dgram_ops;
810 break;
811 case SOCK_SEQPACKET:
812 sock->ops = &unix_seqpacket_ops;
813 break;
814 default:
815 return -ESOCKTNOSUPPORT;
816 }
817
818 return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
819}
820
821static int unix_release(struct socket *sock)
822{
823 struct sock *sk = sock->sk;
824
825 if (!sk)
826 return 0;
827
828 unix_release_sock(sk, 0);
829 sock->sk = NULL;
830
831 return 0;
832}
833
834static int unix_autobind(struct socket *sock)
835{
836 struct sock *sk = sock->sk;
837 struct net *net = sock_net(sk);
838 struct unix_sock *u = unix_sk(sk);
839 static u32 ordernum = 1;
840 struct unix_address *addr;
841 int err;
842 unsigned int retries = 0;
843
844 err = mutex_lock_interruptible(&u->bindlock);
845 if (err)
846 return err;
847
848 err = 0;
849 if (u->addr)
850 goto out;
851
852 err = -ENOMEM;
853 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
854 if (!addr)
855 goto out;
856
857 addr->name->sun_family = AF_UNIX;
858 refcount_set(&addr->refcnt, 1);
859
860retry:
861 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
862 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
863
864 spin_lock(&unix_table_lock);
865 ordernum = (ordernum+1)&0xFFFFF;
866
867 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
868 addr->hash)) {
869 spin_unlock(&unix_table_lock);
870 /*
871 * __unix_find_socket_byname() may take long time if many names
872 * are already in use.
873 */
874 cond_resched();
875 /* Give up if all names seems to be in use. */
876 if (retries++ == 0xFFFFF) {
877 err = -ENOSPC;
878 kfree(addr);
879 goto out;
880 }
881 goto retry;
882 }
883 addr->hash ^= sk->sk_type;
884
885 __unix_remove_socket(sk);
886 u->addr = addr;
887 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
888 spin_unlock(&unix_table_lock);
889 err = 0;
890
891out: mutex_unlock(&u->bindlock);
892 return err;
893}
894
895static struct sock *unix_find_other(struct net *net,
896 struct sockaddr_un *sunname, int len,
897 int type, unsigned int hash, int *error)
898{
899 struct sock *u;
900 struct path path;
901 int err = 0;
902
903 if (sunname->sun_path[0]) {
904 struct inode *inode;
905 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
906 if (err)
907 goto fail;
908 inode = d_backing_inode(path.dentry);
909 err = inode_permission(inode, MAY_WRITE);
910 if (err)
911 goto put_fail;
912
913 err = -ECONNREFUSED;
914 if (!S_ISSOCK(inode->i_mode))
915 goto put_fail;
916 u = unix_find_socket_byinode(inode);
917 if (!u)
918 goto put_fail;
919
920 if (u->sk_type == type)
921 touch_atime(&path);
922
923 path_put(&path);
924
925 err = -EPROTOTYPE;
926 if (u->sk_type != type) {
927 sock_put(u);
928 goto fail;
929 }
930 } else {
931 err = -ECONNREFUSED;
932 u = unix_find_socket_byname(net, sunname, len, type, hash);
933 if (u) {
934 struct dentry *dentry;
935 dentry = unix_sk(u)->path.dentry;
936 if (dentry)
937 touch_atime(&unix_sk(u)->path);
938 } else
939 goto fail;
940 }
941 return u;
942
943put_fail:
944 path_put(&path);
945fail:
946 *error = err;
947 return NULL;
948}
949
950static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
951{
952 struct dentry *dentry;
953 struct path path;
954 int err = 0;
955 /*
956 * Get the parent directory, calculate the hash for last
957 * component.
958 */
959 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
960 err = PTR_ERR(dentry);
961 if (IS_ERR(dentry))
962 return err;
963
964 /*
965 * All right, let's create it.
966 */
967 err = security_path_mknod(&path, dentry, mode, 0);
968 if (!err) {
969 err = vfs_mknod(d_inode(path.dentry), dentry, mode, 0);
970 if (!err) {
971 res->mnt = mntget(path.mnt);
972 res->dentry = dget(dentry);
973 }
974 }
975 done_path_create(&path, dentry);
976 return err;
977}
978
979static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
980{
981 struct sock *sk = sock->sk;
982 struct net *net = sock_net(sk);
983 struct unix_sock *u = unix_sk(sk);
984 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
985 char *sun_path = sunaddr->sun_path;
986 int err;
987 unsigned int hash;
988 struct unix_address *addr;
989 struct hlist_head *list;
990 struct path path = { };
991
992 err = -EINVAL;
993 if (addr_len < offsetofend(struct sockaddr_un, sun_family) ||
994 sunaddr->sun_family != AF_UNIX)
995 goto out;
996
997 if (addr_len == sizeof(short)) {
998 err = unix_autobind(sock);
999 goto out;
1000 }
1001
1002 err = unix_mkname(sunaddr, addr_len, &hash);
1003 if (err < 0)
1004 goto out;
1005 addr_len = err;
1006
1007 if (sun_path[0]) {
1008 umode_t mode = S_IFSOCK |
1009 (SOCK_INODE(sock)->i_mode & ~current_umask());
1010 err = unix_mknod(sun_path, mode, &path);
1011 if (err) {
1012 if (err == -EEXIST)
1013 err = -EADDRINUSE;
1014 goto out;
1015 }
1016 }
1017
1018 err = mutex_lock_interruptible(&u->bindlock);
1019 if (err)
1020 goto out_put;
1021
1022 err = -EINVAL;
1023 if (u->addr)
1024 goto out_up;
1025
1026 err = -ENOMEM;
1027 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
1028 if (!addr)
1029 goto out_up;
1030
1031 memcpy(addr->name, sunaddr, addr_len);
1032 addr->len = addr_len;
1033 addr->hash = hash ^ sk->sk_type;
1034 refcount_set(&addr->refcnt, 1);
1035
1036 if (sun_path[0]) {
1037 addr->hash = UNIX_HASH_SIZE;
1038 hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE - 1);
1039 spin_lock(&unix_table_lock);
1040 u->path = path;
1041 list = &unix_socket_table[hash];
1042 } else {
1043 spin_lock(&unix_table_lock);
1044 err = -EADDRINUSE;
1045 if (__unix_find_socket_byname(net, sunaddr, addr_len,
1046 sk->sk_type, hash)) {
1047 unix_release_addr(addr);
1048 goto out_unlock;
1049 }
1050
1051 list = &unix_socket_table[addr->hash];
1052 }
1053
1054 err = 0;
1055 __unix_remove_socket(sk);
1056 u->addr = addr;
1057 __unix_insert_socket(list, sk);
1058
1059out_unlock:
1060 spin_unlock(&unix_table_lock);
1061out_up:
1062 mutex_unlock(&u->bindlock);
1063out_put:
1064 if (err)
1065 path_put(&path);
1066out:
1067 return err;
1068}
1069
1070static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1071{
1072 if (unlikely(sk1 == sk2) || !sk2) {
1073 unix_state_lock(sk1);
1074 return;
1075 }
1076 if (sk1 < sk2) {
1077 unix_state_lock(sk1);
1078 unix_state_lock_nested(sk2);
1079 } else {
1080 unix_state_lock(sk2);
1081 unix_state_lock_nested(sk1);
1082 }
1083}
1084
1085static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1086{
1087 if (unlikely(sk1 == sk2) || !sk2) {
1088 unix_state_unlock(sk1);
1089 return;
1090 }
1091 unix_state_unlock(sk1);
1092 unix_state_unlock(sk2);
1093}
1094
1095static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1096 int alen, int flags)
1097{
1098 struct sock *sk = sock->sk;
1099 struct net *net = sock_net(sk);
1100 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1101 struct sock *other;
1102 unsigned int hash;
1103 int err;
1104
1105 err = -EINVAL;
1106 if (alen < offsetofend(struct sockaddr, sa_family))
1107 goto out;
1108
1109 if (addr->sa_family != AF_UNSPEC) {
1110 err = unix_mkname(sunaddr, alen, &hash);
1111 if (err < 0)
1112 goto out;
1113 alen = err;
1114
1115 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1116 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1117 goto out;
1118
1119restart:
1120 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1121 if (!other)
1122 goto out;
1123
1124 unix_state_double_lock(sk, other);
1125
1126 /* Apparently VFS overslept socket death. Retry. */
1127 if (sock_flag(other, SOCK_DEAD)) {
1128 unix_state_double_unlock(sk, other);
1129 sock_put(other);
1130 goto restart;
1131 }
1132
1133 err = -EPERM;
1134 if (!unix_may_send(sk, other))
1135 goto out_unlock;
1136
1137 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1138 if (err)
1139 goto out_unlock;
1140
1141 } else {
1142 /*
1143 * 1003.1g breaking connected state with AF_UNSPEC
1144 */
1145 other = NULL;
1146 unix_state_double_lock(sk, other);
1147 }
1148
1149 /*
1150 * If it was connected, reconnect.
1151 */
1152 if (unix_peer(sk)) {
1153 struct sock *old_peer = unix_peer(sk);
1154 unix_peer(sk) = other;
1155 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1156
1157 unix_state_double_unlock(sk, other);
1158
1159 if (other != old_peer)
1160 unix_dgram_disconnected(sk, old_peer);
1161 sock_put(old_peer);
1162 } else {
1163 unix_peer(sk) = other;
1164 unix_state_double_unlock(sk, other);
1165 }
1166 return 0;
1167
1168out_unlock:
1169 unix_state_double_unlock(sk, other);
1170 sock_put(other);
1171out:
1172 return err;
1173}
1174
1175static long unix_wait_for_peer(struct sock *other, long timeo)
1176{
1177 struct unix_sock *u = unix_sk(other);
1178 int sched;
1179 DEFINE_WAIT(wait);
1180
1181 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1182
1183 sched = !sock_flag(other, SOCK_DEAD) &&
1184 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1185 unix_recvq_full(other);
1186
1187 unix_state_unlock(other);
1188
1189 if (sched)
1190 timeo = schedule_timeout(timeo);
1191
1192 finish_wait(&u->peer_wait, &wait);
1193 return timeo;
1194}
1195
1196static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1197 int addr_len, int flags)
1198{
1199 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1200 struct sock *sk = sock->sk;
1201 struct net *net = sock_net(sk);
1202 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1203 struct sock *newsk = NULL;
1204 struct sock *other = NULL;
1205 struct sk_buff *skb = NULL;
1206 unsigned int hash;
1207 int st;
1208 int err;
1209 long timeo;
1210
1211 err = unix_mkname(sunaddr, addr_len, &hash);
1212 if (err < 0)
1213 goto out;
1214 addr_len = err;
1215
1216 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1217 (err = unix_autobind(sock)) != 0)
1218 goto out;
1219
1220 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1221
1222 /* First of all allocate resources.
1223 If we will make it after state is locked,
1224 we will have to recheck all again in any case.
1225 */
1226
1227 err = -ENOMEM;
1228
1229 /* create new sock for complete connection */
1230 newsk = unix_create1(sock_net(sk), NULL, 0);
1231 if (newsk == NULL)
1232 goto out;
1233
1234 /* Allocate skb for sending to listening sock */
1235 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1236 if (skb == NULL)
1237 goto out;
1238
1239restart:
1240 /* Find listening sock. */
1241 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1242 if (!other)
1243 goto out;
1244
1245 /* Latch state of peer */
1246 unix_state_lock(other);
1247
1248 /* Apparently VFS overslept socket death. Retry. */
1249 if (sock_flag(other, SOCK_DEAD)) {
1250 unix_state_unlock(other);
1251 sock_put(other);
1252 goto restart;
1253 }
1254
1255 err = -ECONNREFUSED;
1256 if (other->sk_state != TCP_LISTEN)
1257 goto out_unlock;
1258 if (other->sk_shutdown & RCV_SHUTDOWN)
1259 goto out_unlock;
1260
1261 if (unix_recvq_full(other)) {
1262 err = -EAGAIN;
1263 if (!timeo)
1264 goto out_unlock;
1265
1266 timeo = unix_wait_for_peer(other, timeo);
1267
1268 err = sock_intr_errno(timeo);
1269 if (signal_pending(current))
1270 goto out;
1271 sock_put(other);
1272 goto restart;
1273 }
1274
1275 /* Latch our state.
1276
1277 It is tricky place. We need to grab our state lock and cannot
1278 drop lock on peer. It is dangerous because deadlock is
1279 possible. Connect to self case and simultaneous
1280 attempt to connect are eliminated by checking socket
1281 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1282 check this before attempt to grab lock.
1283
1284 Well, and we have to recheck the state after socket locked.
1285 */
1286 st = sk->sk_state;
1287
1288 switch (st) {
1289 case TCP_CLOSE:
1290 /* This is ok... continue with connect */
1291 break;
1292 case TCP_ESTABLISHED:
1293 /* Socket is already connected */
1294 err = -EISCONN;
1295 goto out_unlock;
1296 default:
1297 err = -EINVAL;
1298 goto out_unlock;
1299 }
1300
1301 unix_state_lock_nested(sk);
1302
1303 if (sk->sk_state != st) {
1304 unix_state_unlock(sk);
1305 unix_state_unlock(other);
1306 sock_put(other);
1307 goto restart;
1308 }
1309
1310 err = security_unix_stream_connect(sk, other, newsk);
1311 if (err) {
1312 unix_state_unlock(sk);
1313 goto out_unlock;
1314 }
1315
1316 /* The way is open! Fastly set all the necessary fields... */
1317
1318 sock_hold(sk);
1319 unix_peer(newsk) = sk;
1320 newsk->sk_state = TCP_ESTABLISHED;
1321 newsk->sk_type = sk->sk_type;
1322 init_peercred(newsk);
1323 newu = unix_sk(newsk);
1324 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1325 otheru = unix_sk(other);
1326
1327 /* copy address information from listening to new sock*/
1328 if (otheru->addr) {
1329 refcount_inc(&otheru->addr->refcnt);
1330 newu->addr = otheru->addr;
1331 }
1332 if (otheru->path.dentry) {
1333 path_get(&otheru->path);
1334 newu->path = otheru->path;
1335 }
1336
1337 /* Set credentials */
1338 copy_peercred(sk, other);
1339
1340 sock->state = SS_CONNECTED;
1341 sk->sk_state = TCP_ESTABLISHED;
1342 sock_hold(newsk);
1343
1344 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1345 unix_peer(sk) = newsk;
1346
1347 unix_state_unlock(sk);
1348
1349 /* take ten and and send info to listening sock */
1350 spin_lock(&other->sk_receive_queue.lock);
1351 __skb_queue_tail(&other->sk_receive_queue, skb);
1352 spin_unlock(&other->sk_receive_queue.lock);
1353 unix_state_unlock(other);
1354 other->sk_data_ready(other);
1355 sock_put(other);
1356 return 0;
1357
1358out_unlock:
1359 if (other)
1360 unix_state_unlock(other);
1361
1362out:
1363 kfree_skb(skb);
1364 if (newsk)
1365 unix_release_sock(newsk, 0);
1366 if (other)
1367 sock_put(other);
1368 return err;
1369}
1370
1371static int unix_socketpair(struct socket *socka, struct socket *sockb)
1372{
1373 struct sock *ska = socka->sk, *skb = sockb->sk;
1374
1375 /* Join our sockets back to back */
1376 sock_hold(ska);
1377 sock_hold(skb);
1378 unix_peer(ska) = skb;
1379 unix_peer(skb) = ska;
1380 init_peercred(ska);
1381 init_peercred(skb);
1382
1383 if (ska->sk_type != SOCK_DGRAM) {
1384 ska->sk_state = TCP_ESTABLISHED;
1385 skb->sk_state = TCP_ESTABLISHED;
1386 socka->state = SS_CONNECTED;
1387 sockb->state = SS_CONNECTED;
1388 }
1389 return 0;
1390}
1391
1392static void unix_sock_inherit_flags(const struct socket *old,
1393 struct socket *new)
1394{
1395 if (test_bit(SOCK_PASSCRED, &old->flags))
1396 set_bit(SOCK_PASSCRED, &new->flags);
1397 if (test_bit(SOCK_PASSSEC, &old->flags))
1398 set_bit(SOCK_PASSSEC, &new->flags);
1399}
1400
1401static int unix_accept(struct socket *sock, struct socket *newsock, int flags,
1402 bool kern)
1403{
1404 struct sock *sk = sock->sk;
1405 struct sock *tsk;
1406 struct sk_buff *skb;
1407 int err;
1408
1409 err = -EOPNOTSUPP;
1410 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1411 goto out;
1412
1413 err = -EINVAL;
1414 if (sk->sk_state != TCP_LISTEN)
1415 goto out;
1416
1417 /* If socket state is TCP_LISTEN it cannot change (for now...),
1418 * so that no locks are necessary.
1419 */
1420
1421 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1422 if (!skb) {
1423 /* This means receive shutdown. */
1424 if (err == 0)
1425 err = -EINVAL;
1426 goto out;
1427 }
1428
1429 tsk = skb->sk;
1430 skb_free_datagram(sk, skb);
1431 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1432
1433 /* attach accepted sock to socket */
1434 unix_state_lock(tsk);
1435 newsock->state = SS_CONNECTED;
1436 unix_sock_inherit_flags(sock, newsock);
1437 sock_graft(tsk, newsock);
1438 unix_state_unlock(tsk);
1439 return 0;
1440
1441out:
1442 return err;
1443}
1444
1445
1446static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1447{
1448 struct sock *sk = sock->sk;
1449 struct unix_sock *u;
1450 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1451 int err = 0;
1452
1453 if (peer) {
1454 sk = unix_peer_get(sk);
1455
1456 err = -ENOTCONN;
1457 if (!sk)
1458 goto out;
1459 err = 0;
1460 } else {
1461 sock_hold(sk);
1462 }
1463
1464 u = unix_sk(sk);
1465 unix_state_lock(sk);
1466 if (!u->addr) {
1467 sunaddr->sun_family = AF_UNIX;
1468 sunaddr->sun_path[0] = 0;
1469 err = sizeof(short);
1470 } else {
1471 struct unix_address *addr = u->addr;
1472
1473 err = addr->len;
1474 memcpy(sunaddr, addr->name, addr->len);
1475 }
1476 unix_state_unlock(sk);
1477 sock_put(sk);
1478out:
1479 return err;
1480}
1481
1482static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1483{
1484 int i;
1485
1486 scm->fp = UNIXCB(skb).fp;
1487 UNIXCB(skb).fp = NULL;
1488
1489 for (i = scm->fp->count-1; i >= 0; i--)
1490 unix_notinflight(scm->fp->user, scm->fp->fp[i]);
1491}
1492
1493static void unix_destruct_scm(struct sk_buff *skb)
1494{
1495 struct scm_cookie scm;
1496 memset(&scm, 0, sizeof(scm));
1497 scm.pid = UNIXCB(skb).pid;
1498 if (UNIXCB(skb).fp)
1499 unix_detach_fds(&scm, skb);
1500
1501 /* Alas, it calls VFS */
1502 /* So fscking what? fput() had been SMP-safe since the last Summer */
1503 scm_destroy(&scm);
1504 sock_wfree(skb);
1505}
1506
1507/*
1508 * The "user->unix_inflight" variable is protected by the garbage
1509 * collection lock, and we just read it locklessly here. If you go
1510 * over the limit, there might be a tiny race in actually noticing
1511 * it across threads. Tough.
1512 */
1513static inline bool too_many_unix_fds(struct task_struct *p)
1514{
1515 struct user_struct *user = current_user();
1516
1517 if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
1518 return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1519 return false;
1520}
1521
1522static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1523{
1524 int i;
1525
1526 if (too_many_unix_fds(current))
1527 return -ETOOMANYREFS;
1528
1529 /*
1530 * Need to duplicate file references for the sake of garbage
1531 * collection. Otherwise a socket in the fps might become a
1532 * candidate for GC while the skb is not yet queued.
1533 */
1534 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1535 if (!UNIXCB(skb).fp)
1536 return -ENOMEM;
1537
1538 for (i = scm->fp->count - 1; i >= 0; i--)
1539 unix_inflight(scm->fp->user, scm->fp->fp[i]);
1540 return 0;
1541}
1542
1543static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1544{
1545 int err = 0;
1546
1547 UNIXCB(skb).pid = get_pid(scm->pid);
1548 UNIXCB(skb).uid = scm->creds.uid;
1549 UNIXCB(skb).gid = scm->creds.gid;
1550 UNIXCB(skb).fp = NULL;
1551 unix_get_secdata(scm, skb);
1552 if (scm->fp && send_fds)
1553 err = unix_attach_fds(scm, skb);
1554
1555 skb->destructor = unix_destruct_scm;
1556 return err;
1557}
1558
1559static bool unix_passcred_enabled(const struct socket *sock,
1560 const struct sock *other)
1561{
1562 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1563 !other->sk_socket ||
1564 test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1565}
1566
1567/*
1568 * Some apps rely on write() giving SCM_CREDENTIALS
1569 * We include credentials if source or destination socket
1570 * asserted SOCK_PASSCRED.
1571 */
1572static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1573 const struct sock *other)
1574{
1575 if (UNIXCB(skb).pid)
1576 return;
1577 if (unix_passcred_enabled(sock, other)) {
1578 UNIXCB(skb).pid = get_pid(task_tgid(current));
1579 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1580 }
1581}
1582
1583static int maybe_init_creds(struct scm_cookie *scm,
1584 struct socket *socket,
1585 const struct sock *other)
1586{
1587 int err;
1588 struct msghdr msg = { .msg_controllen = 0 };
1589
1590 err = scm_send(socket, &msg, scm, false);
1591 if (err)
1592 return err;
1593
1594 if (unix_passcred_enabled(socket, other)) {
1595 scm->pid = get_pid(task_tgid(current));
1596 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1597 }
1598 return err;
1599}
1600
1601static bool unix_skb_scm_eq(struct sk_buff *skb,
1602 struct scm_cookie *scm)
1603{
1604 const struct unix_skb_parms *u = &UNIXCB(skb);
1605
1606 return u->pid == scm->pid &&
1607 uid_eq(u->uid, scm->creds.uid) &&
1608 gid_eq(u->gid, scm->creds.gid) &&
1609 unix_secdata_eq(scm, skb);
1610}
1611
1612/*
1613 * Send AF_UNIX data.
1614 */
1615
1616static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1617 size_t len)
1618{
1619 struct sock *sk = sock->sk;
1620 struct net *net = sock_net(sk);
1621 struct unix_sock *u = unix_sk(sk);
1622 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1623 struct sock *other = NULL;
1624 int namelen = 0; /* fake GCC */
1625 int err;
1626 unsigned int hash;
1627 struct sk_buff *skb;
1628 long timeo;
1629 struct scm_cookie scm;
1630 int data_len = 0;
1631 int sk_locked;
1632
1633 wait_for_unix_gc();
1634 err = scm_send(sock, msg, &scm, false);
1635 if (err < 0)
1636 return err;
1637
1638 err = -EOPNOTSUPP;
1639 if (msg->msg_flags&MSG_OOB)
1640 goto out;
1641
1642 if (msg->msg_namelen) {
1643 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1644 if (err < 0)
1645 goto out;
1646 namelen = err;
1647 } else {
1648 sunaddr = NULL;
1649 err = -ENOTCONN;
1650 other = unix_peer_get(sk);
1651 if (!other)
1652 goto out;
1653 }
1654
1655 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1656 && (err = unix_autobind(sock)) != 0)
1657 goto out;
1658
1659 err = -EMSGSIZE;
1660 if (len > sk->sk_sndbuf - 32)
1661 goto out;
1662
1663 if (len > SKB_MAX_ALLOC) {
1664 data_len = min_t(size_t,
1665 len - SKB_MAX_ALLOC,
1666 MAX_SKB_FRAGS * PAGE_SIZE);
1667 data_len = PAGE_ALIGN(data_len);
1668
1669 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1670 }
1671
1672 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1673 msg->msg_flags & MSG_DONTWAIT, &err,
1674 PAGE_ALLOC_COSTLY_ORDER);
1675 if (skb == NULL)
1676 goto out;
1677
1678 err = unix_scm_to_skb(&scm, skb, true);
1679 if (err < 0)
1680 goto out_free;
1681
1682 skb_put(skb, len - data_len);
1683 skb->data_len = data_len;
1684 skb->len = len;
1685 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1686 if (err)
1687 goto out_free;
1688
1689 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1690
1691restart:
1692 if (!other) {
1693 err = -ECONNRESET;
1694 if (sunaddr == NULL)
1695 goto out_free;
1696
1697 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1698 hash, &err);
1699 if (other == NULL)
1700 goto out_free;
1701 }
1702
1703 if (sk_filter(other, skb) < 0) {
1704 /* Toss the packet but do not return any error to the sender */
1705 err = len;
1706 goto out_free;
1707 }
1708
1709 sk_locked = 0;
1710 unix_state_lock(other);
1711restart_locked:
1712 err = -EPERM;
1713 if (!unix_may_send(sk, other))
1714 goto out_unlock;
1715
1716 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1717 /*
1718 * Check with 1003.1g - what should
1719 * datagram error
1720 */
1721 unix_state_unlock(other);
1722 sock_put(other);
1723
1724 if (!sk_locked)
1725 unix_state_lock(sk);
1726
1727 err = 0;
1728 if (unix_peer(sk) == other) {
1729 unix_peer(sk) = NULL;
1730 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1731
1732 unix_state_unlock(sk);
1733
1734 unix_dgram_disconnected(sk, other);
1735 sock_put(other);
1736 err = -ECONNREFUSED;
1737 } else {
1738 unix_state_unlock(sk);
1739 }
1740
1741 other = NULL;
1742 if (err)
1743 goto out_free;
1744 goto restart;
1745 }
1746
1747 err = -EPIPE;
1748 if (other->sk_shutdown & RCV_SHUTDOWN)
1749 goto out_unlock;
1750
1751 if (sk->sk_type != SOCK_SEQPACKET) {
1752 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1753 if (err)
1754 goto out_unlock;
1755 }
1756
1757 /* other == sk && unix_peer(other) != sk if
1758 * - unix_peer(sk) == NULL, destination address bound to sk
1759 * - unix_peer(sk) == sk by time of get but disconnected before lock
1760 */
1761 if (other != sk &&
1762 unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1763 if (timeo) {
1764 timeo = unix_wait_for_peer(other, timeo);
1765
1766 err = sock_intr_errno(timeo);
1767 if (signal_pending(current))
1768 goto out_free;
1769
1770 goto restart;
1771 }
1772
1773 if (!sk_locked) {
1774 unix_state_unlock(other);
1775 unix_state_double_lock(sk, other);
1776 }
1777
1778 if (unix_peer(sk) != other ||
1779 unix_dgram_peer_wake_me(sk, other)) {
1780 err = -EAGAIN;
1781 sk_locked = 1;
1782 goto out_unlock;
1783 }
1784
1785 if (!sk_locked) {
1786 sk_locked = 1;
1787 goto restart_locked;
1788 }
1789 }
1790
1791 if (unlikely(sk_locked))
1792 unix_state_unlock(sk);
1793
1794 if (sock_flag(other, SOCK_RCVTSTAMP))
1795 __net_timestamp(skb);
1796 maybe_add_creds(skb, sock, other);
1797 skb_queue_tail(&other->sk_receive_queue, skb);
1798 unix_state_unlock(other);
1799 other->sk_data_ready(other);
1800 sock_put(other);
1801 scm_destroy(&scm);
1802 return len;
1803
1804out_unlock:
1805 if (sk_locked)
1806 unix_state_unlock(sk);
1807 unix_state_unlock(other);
1808out_free:
1809 kfree_skb(skb);
1810out:
1811 if (other)
1812 sock_put(other);
1813 scm_destroy(&scm);
1814 return err;
1815}
1816
1817/* We use paged skbs for stream sockets, and limit occupancy to 32768
1818 * bytes, and a minimum of a full page.
1819 */
1820#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1821
1822static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
1823 size_t len)
1824{
1825 struct sock *sk = sock->sk;
1826 struct sock *other = NULL;
1827 int err, size;
1828 struct sk_buff *skb;
1829 int sent = 0;
1830 struct scm_cookie scm;
1831 bool fds_sent = false;
1832 int data_len;
1833
1834 wait_for_unix_gc();
1835 err = scm_send(sock, msg, &scm, false);
1836 if (err < 0)
1837 return err;
1838
1839 err = -EOPNOTSUPP;
1840 if (msg->msg_flags&MSG_OOB)
1841 goto out_err;
1842
1843 if (msg->msg_namelen) {
1844 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1845 goto out_err;
1846 } else {
1847 err = -ENOTCONN;
1848 other = unix_peer(sk);
1849 if (!other)
1850 goto out_err;
1851 }
1852
1853 if (sk->sk_shutdown & SEND_SHUTDOWN)
1854 goto pipe_err;
1855
1856 while (sent < len) {
1857 size = len - sent;
1858
1859 /* Keep two messages in the pipe so it schedules better */
1860 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1861
1862 /* allow fallback to order-0 allocations */
1863 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1864
1865 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1866
1867 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
1868
1869 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1870 msg->msg_flags & MSG_DONTWAIT, &err,
1871 get_order(UNIX_SKB_FRAGS_SZ));
1872 if (!skb)
1873 goto out_err;
1874
1875 /* Only send the fds in the first buffer */
1876 err = unix_scm_to_skb(&scm, skb, !fds_sent);
1877 if (err < 0) {
1878 kfree_skb(skb);
1879 goto out_err;
1880 }
1881 fds_sent = true;
1882
1883 skb_put(skb, size - data_len);
1884 skb->data_len = data_len;
1885 skb->len = size;
1886 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
1887 if (err) {
1888 kfree_skb(skb);
1889 goto out_err;
1890 }
1891
1892 unix_state_lock(other);
1893
1894 if (sock_flag(other, SOCK_DEAD) ||
1895 (other->sk_shutdown & RCV_SHUTDOWN))
1896 goto pipe_err_free;
1897
1898 maybe_add_creds(skb, sock, other);
1899 skb_queue_tail(&other->sk_receive_queue, skb);
1900 unix_state_unlock(other);
1901 other->sk_data_ready(other);
1902 sent += size;
1903 }
1904
1905 scm_destroy(&scm);
1906
1907 return sent;
1908
1909pipe_err_free:
1910 unix_state_unlock(other);
1911 kfree_skb(skb);
1912pipe_err:
1913 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1914 send_sig(SIGPIPE, current, 0);
1915 err = -EPIPE;
1916out_err:
1917 scm_destroy(&scm);
1918 return sent ? : err;
1919}
1920
1921static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
1922 int offset, size_t size, int flags)
1923{
1924 int err;
1925 bool send_sigpipe = false;
1926 bool init_scm = true;
1927 struct scm_cookie scm;
1928 struct sock *other, *sk = socket->sk;
1929 struct sk_buff *skb, *newskb = NULL, *tail = NULL;
1930
1931 if (flags & MSG_OOB)
1932 return -EOPNOTSUPP;
1933
1934 other = unix_peer(sk);
1935 if (!other || sk->sk_state != TCP_ESTABLISHED)
1936 return -ENOTCONN;
1937
1938 if (false) {
1939alloc_skb:
1940 unix_state_unlock(other);
1941 mutex_unlock(&unix_sk(other)->iolock);
1942 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
1943 &err, 0);
1944 if (!newskb)
1945 goto err;
1946 }
1947
1948 /* we must acquire iolock as we modify already present
1949 * skbs in the sk_receive_queue and mess with skb->len
1950 */
1951 err = mutex_lock_interruptible(&unix_sk(other)->iolock);
1952 if (err) {
1953 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
1954 goto err;
1955 }
1956
1957 if (sk->sk_shutdown & SEND_SHUTDOWN) {
1958 err = -EPIPE;
1959 send_sigpipe = true;
1960 goto err_unlock;
1961 }
1962
1963 unix_state_lock(other);
1964
1965 if (sock_flag(other, SOCK_DEAD) ||
1966 other->sk_shutdown & RCV_SHUTDOWN) {
1967 err = -EPIPE;
1968 send_sigpipe = true;
1969 goto err_state_unlock;
1970 }
1971
1972 if (init_scm) {
1973 err = maybe_init_creds(&scm, socket, other);
1974 if (err)
1975 goto err_state_unlock;
1976 init_scm = false;
1977 }
1978
1979 skb = skb_peek_tail(&other->sk_receive_queue);
1980 if (tail && tail == skb) {
1981 skb = newskb;
1982 } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
1983 if (newskb) {
1984 skb = newskb;
1985 } else {
1986 tail = skb;
1987 goto alloc_skb;
1988 }
1989 } else if (newskb) {
1990 /* this is fast path, we don't necessarily need to
1991 * call to kfree_skb even though with newskb == NULL
1992 * this - does no harm
1993 */
1994 consume_skb(newskb);
1995 newskb = NULL;
1996 }
1997
1998 if (skb_append_pagefrags(skb, page, offset, size)) {
1999 tail = skb;
2000 goto alloc_skb;
2001 }
2002
2003 skb->len += size;
2004 skb->data_len += size;
2005 skb->truesize += size;
2006 refcount_add(size, &sk->sk_wmem_alloc);
2007
2008 if (newskb) {
2009 err = unix_scm_to_skb(&scm, skb, false);
2010 if (err)
2011 goto err_state_unlock;
2012 spin_lock(&other->sk_receive_queue.lock);
2013 __skb_queue_tail(&other->sk_receive_queue, newskb);
2014 spin_unlock(&other->sk_receive_queue.lock);
2015 }
2016
2017 unix_state_unlock(other);
2018 mutex_unlock(&unix_sk(other)->iolock);
2019
2020 other->sk_data_ready(other);
2021 scm_destroy(&scm);
2022 return size;
2023
2024err_state_unlock:
2025 unix_state_unlock(other);
2026err_unlock:
2027 mutex_unlock(&unix_sk(other)->iolock);
2028err:
2029 kfree_skb(newskb);
2030 if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2031 send_sig(SIGPIPE, current, 0);
2032 if (!init_scm)
2033 scm_destroy(&scm);
2034 return err;
2035}
2036
2037static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2038 size_t len)
2039{
2040 int err;
2041 struct sock *sk = sock->sk;
2042
2043 err = sock_error(sk);
2044 if (err)
2045 return err;
2046
2047 if (sk->sk_state != TCP_ESTABLISHED)
2048 return -ENOTCONN;
2049
2050 if (msg->msg_namelen)
2051 msg->msg_namelen = 0;
2052
2053 return unix_dgram_sendmsg(sock, msg, len);
2054}
2055
2056static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2057 size_t size, int flags)
2058{
2059 struct sock *sk = sock->sk;
2060
2061 if (sk->sk_state != TCP_ESTABLISHED)
2062 return -ENOTCONN;
2063
2064 return unix_dgram_recvmsg(sock, msg, size, flags);
2065}
2066
2067static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2068{
2069 struct unix_sock *u = unix_sk(sk);
2070
2071 if (u->addr) {
2072 msg->msg_namelen = u->addr->len;
2073 memcpy(msg->msg_name, u->addr->name, u->addr->len);
2074 }
2075}
2076
2077static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
2078 size_t size, int flags)
2079{
2080 struct scm_cookie scm;
2081 struct sock *sk = sock->sk;
2082 struct unix_sock *u = unix_sk(sk);
2083 struct sk_buff *skb, *last;
2084 long timeo;
2085 int err;
2086 int peeked, skip;
2087
2088 err = -EOPNOTSUPP;
2089 if (flags&MSG_OOB)
2090 goto out;
2091
2092 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2093
2094 do {
2095 mutex_lock(&u->iolock);
2096
2097 skip = sk_peek_offset(sk, flags);
2098 skb = __skb_try_recv_datagram(sk, flags, NULL, &peeked, &skip,
2099 &err, &last);
2100 if (skb)
2101 break;
2102
2103 mutex_unlock(&u->iolock);
2104
2105 if (err != -EAGAIN)
2106 break;
2107 } while (timeo &&
2108 !__skb_wait_for_more_packets(sk, &err, &timeo, last));
2109
2110 if (!skb) { /* implies iolock unlocked */
2111 unix_state_lock(sk);
2112 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2113 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2114 (sk->sk_shutdown & RCV_SHUTDOWN))
2115 err = 0;
2116 unix_state_unlock(sk);
2117 goto out;
2118 }
2119
2120 if (wq_has_sleeper(&u->peer_wait))
2121 wake_up_interruptible_sync_poll(&u->peer_wait,
2122 EPOLLOUT | EPOLLWRNORM |
2123 EPOLLWRBAND);
2124
2125 if (msg->msg_name)
2126 unix_copy_addr(msg, skb->sk);
2127
2128 if (size > skb->len - skip)
2129 size = skb->len - skip;
2130 else if (size < skb->len - skip)
2131 msg->msg_flags |= MSG_TRUNC;
2132
2133 err = skb_copy_datagram_msg(skb, skip, msg, size);
2134 if (err)
2135 goto out_free;
2136
2137 if (sock_flag(sk, SOCK_RCVTSTAMP))
2138 __sock_recv_timestamp(msg, sk, skb);
2139
2140 memset(&scm, 0, sizeof(scm));
2141
2142 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2143 unix_set_secdata(&scm, skb);
2144
2145 if (!(flags & MSG_PEEK)) {
2146 if (UNIXCB(skb).fp)
2147 unix_detach_fds(&scm, skb);
2148
2149 sk_peek_offset_bwd(sk, skb->len);
2150 } else {
2151 /* It is questionable: on PEEK we could:
2152 - do not return fds - good, but too simple 8)
2153 - return fds, and do not return them on read (old strategy,
2154 apparently wrong)
2155 - clone fds (I chose it for now, it is the most universal
2156 solution)
2157
2158 POSIX 1003.1g does not actually define this clearly
2159 at all. POSIX 1003.1g doesn't define a lot of things
2160 clearly however!
2161
2162 */
2163
2164 sk_peek_offset_fwd(sk, size);
2165
2166 if (UNIXCB(skb).fp)
2167 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2168 }
2169 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2170
2171 scm_recv(sock, msg, &scm, flags);
2172
2173out_free:
2174 skb_free_datagram(sk, skb);
2175 mutex_unlock(&u->iolock);
2176out:
2177 return err;
2178}
2179
2180/*
2181 * Sleep until more data has arrived. But check for races..
2182 */
2183static long unix_stream_data_wait(struct sock *sk, long timeo,
2184 struct sk_buff *last, unsigned int last_len,
2185 bool freezable)
2186{
2187 struct sk_buff *tail;
2188 DEFINE_WAIT(wait);
2189
2190 unix_state_lock(sk);
2191
2192 for (;;) {
2193 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2194
2195 tail = skb_peek_tail(&sk->sk_receive_queue);
2196 if (tail != last ||
2197 (tail && tail->len != last_len) ||
2198 sk->sk_err ||
2199 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2200 signal_pending(current) ||
2201 !timeo)
2202 break;
2203
2204 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2205 unix_state_unlock(sk);
2206 if (freezable)
2207 timeo = freezable_schedule_timeout(timeo);
2208 else
2209 timeo = schedule_timeout(timeo);
2210 unix_state_lock(sk);
2211
2212 if (sock_flag(sk, SOCK_DEAD))
2213 break;
2214
2215 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2216 }
2217
2218 finish_wait(sk_sleep(sk), &wait);
2219 unix_state_unlock(sk);
2220 return timeo;
2221}
2222
2223static unsigned int unix_skb_len(const struct sk_buff *skb)
2224{
2225 return skb->len - UNIXCB(skb).consumed;
2226}
2227
2228struct unix_stream_read_state {
2229 int (*recv_actor)(struct sk_buff *, int, int,
2230 struct unix_stream_read_state *);
2231 struct socket *socket;
2232 struct msghdr *msg;
2233 struct pipe_inode_info *pipe;
2234 size_t size;
2235 int flags;
2236 unsigned int splice_flags;
2237};
2238
2239static int unix_stream_read_generic(struct unix_stream_read_state *state,
2240 bool freezable)
2241{
2242 struct scm_cookie scm;
2243 struct socket *sock = state->socket;
2244 struct sock *sk = sock->sk;
2245 struct unix_sock *u = unix_sk(sk);
2246 int copied = 0;
2247 int flags = state->flags;
2248 int noblock = flags & MSG_DONTWAIT;
2249 bool check_creds = false;
2250 int target;
2251 int err = 0;
2252 long timeo;
2253 int skip;
2254 size_t size = state->size;
2255 unsigned int last_len;
2256
2257 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2258 err = -EINVAL;
2259 goto out;
2260 }
2261
2262 if (unlikely(flags & MSG_OOB)) {
2263 err = -EOPNOTSUPP;
2264 goto out;
2265 }
2266
2267 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2268 timeo = sock_rcvtimeo(sk, noblock);
2269
2270 memset(&scm, 0, sizeof(scm));
2271
2272 /* Lock the socket to prevent queue disordering
2273 * while sleeps in memcpy_tomsg
2274 */
2275 mutex_lock(&u->iolock);
2276
2277 skip = max(sk_peek_offset(sk, flags), 0);
2278
2279 do {
2280 int chunk;
2281 bool drop_skb;
2282 struct sk_buff *skb, *last;
2283
2284redo:
2285 unix_state_lock(sk);
2286 if (sock_flag(sk, SOCK_DEAD)) {
2287 err = -ECONNRESET;
2288 goto unlock;
2289 }
2290 last = skb = skb_peek(&sk->sk_receive_queue);
2291 last_len = last ? last->len : 0;
2292again:
2293 if (skb == NULL) {
2294 if (copied >= target)
2295 goto unlock;
2296
2297 /*
2298 * POSIX 1003.1g mandates this order.
2299 */
2300
2301 err = sock_error(sk);
2302 if (err)
2303 goto unlock;
2304 if (sk->sk_shutdown & RCV_SHUTDOWN)
2305 goto unlock;
2306
2307 unix_state_unlock(sk);
2308 if (!timeo) {
2309 err = -EAGAIN;
2310 break;
2311 }
2312
2313 mutex_unlock(&u->iolock);
2314
2315 timeo = unix_stream_data_wait(sk, timeo, last,
2316 last_len, freezable);
2317
2318 if (signal_pending(current)) {
2319 err = sock_intr_errno(timeo);
2320 scm_destroy(&scm);
2321 goto out;
2322 }
2323
2324 mutex_lock(&u->iolock);
2325 goto redo;
2326unlock:
2327 unix_state_unlock(sk);
2328 break;
2329 }
2330
2331 while (skip >= unix_skb_len(skb)) {
2332 skip -= unix_skb_len(skb);
2333 last = skb;
2334 last_len = skb->len;
2335 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2336 if (!skb)
2337 goto again;
2338 }
2339
2340 unix_state_unlock(sk);
2341
2342 if (check_creds) {
2343 /* Never glue messages from different writers */
2344 if (!unix_skb_scm_eq(skb, &scm))
2345 break;
2346 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2347 /* Copy credentials */
2348 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2349 unix_set_secdata(&scm, skb);
2350 check_creds = true;
2351 }
2352
2353 /* Copy address just once */
2354 if (state->msg && state->msg->msg_name) {
2355 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2356 state->msg->msg_name);
2357 unix_copy_addr(state->msg, skb->sk);
2358 sunaddr = NULL;
2359 }
2360
2361 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2362 skb_get(skb);
2363 chunk = state->recv_actor(skb, skip, chunk, state);
2364 drop_skb = !unix_skb_len(skb);
2365 /* skb is only safe to use if !drop_skb */
2366 consume_skb(skb);
2367 if (chunk < 0) {
2368 if (copied == 0)
2369 copied = -EFAULT;
2370 break;
2371 }
2372 copied += chunk;
2373 size -= chunk;
2374
2375 if (drop_skb) {
2376 /* the skb was touched by a concurrent reader;
2377 * we should not expect anything from this skb
2378 * anymore and assume it invalid - we can be
2379 * sure it was dropped from the socket queue
2380 *
2381 * let's report a short read
2382 */
2383 err = 0;
2384 break;
2385 }
2386
2387 /* Mark read part of skb as used */
2388 if (!(flags & MSG_PEEK)) {
2389 UNIXCB(skb).consumed += chunk;
2390
2391 sk_peek_offset_bwd(sk, chunk);
2392
2393 if (UNIXCB(skb).fp)
2394 unix_detach_fds(&scm, skb);
2395
2396 if (unix_skb_len(skb))
2397 break;
2398
2399 skb_unlink(skb, &sk->sk_receive_queue);
2400 consume_skb(skb);
2401
2402 if (scm.fp)
2403 break;
2404 } else {
2405 /* It is questionable, see note in unix_dgram_recvmsg.
2406 */
2407 if (UNIXCB(skb).fp)
2408 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2409
2410 sk_peek_offset_fwd(sk, chunk);
2411
2412 if (UNIXCB(skb).fp)
2413 break;
2414
2415 skip = 0;
2416 last = skb;
2417 last_len = skb->len;
2418 unix_state_lock(sk);
2419 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2420 if (skb)
2421 goto again;
2422 unix_state_unlock(sk);
2423 break;
2424 }
2425 } while (size);
2426
2427 mutex_unlock(&u->iolock);
2428 if (state->msg)
2429 scm_recv(sock, state->msg, &scm, flags);
2430 else
2431 scm_destroy(&scm);
2432out:
2433 return copied ? : err;
2434}
2435
2436static int unix_stream_read_actor(struct sk_buff *skb,
2437 int skip, int chunk,
2438 struct unix_stream_read_state *state)
2439{
2440 int ret;
2441
2442 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2443 state->msg, chunk);
2444 return ret ?: chunk;
2445}
2446
2447static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2448 size_t size, int flags)
2449{
2450 struct unix_stream_read_state state = {
2451 .recv_actor = unix_stream_read_actor,
2452 .socket = sock,
2453 .msg = msg,
2454 .size = size,
2455 .flags = flags
2456 };
2457
2458 return unix_stream_read_generic(&state, true);
2459}
2460
2461static int unix_stream_splice_actor(struct sk_buff *skb,
2462 int skip, int chunk,
2463 struct unix_stream_read_state *state)
2464{
2465 return skb_splice_bits(skb, state->socket->sk,
2466 UNIXCB(skb).consumed + skip,
2467 state->pipe, chunk, state->splice_flags);
2468}
2469
2470static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2471 struct pipe_inode_info *pipe,
2472 size_t size, unsigned int flags)
2473{
2474 struct unix_stream_read_state state = {
2475 .recv_actor = unix_stream_splice_actor,
2476 .socket = sock,
2477 .pipe = pipe,
2478 .size = size,
2479 .splice_flags = flags,
2480 };
2481
2482 if (unlikely(*ppos))
2483 return -ESPIPE;
2484
2485 if (sock->file->f_flags & O_NONBLOCK ||
2486 flags & SPLICE_F_NONBLOCK)
2487 state.flags = MSG_DONTWAIT;
2488
2489 return unix_stream_read_generic(&state, false);
2490}
2491
2492static int unix_shutdown(struct socket *sock, int mode)
2493{
2494 struct sock *sk = sock->sk;
2495 struct sock *other;
2496
2497 if (mode < SHUT_RD || mode > SHUT_RDWR)
2498 return -EINVAL;
2499 /* This maps:
2500 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2501 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2502 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2503 */
2504 ++mode;
2505
2506 unix_state_lock(sk);
2507 sk->sk_shutdown |= mode;
2508 other = unix_peer(sk);
2509 if (other)
2510 sock_hold(other);
2511 unix_state_unlock(sk);
2512 sk->sk_state_change(sk);
2513
2514 if (other &&
2515 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2516
2517 int peer_mode = 0;
2518
2519 if (mode&RCV_SHUTDOWN)
2520 peer_mode |= SEND_SHUTDOWN;
2521 if (mode&SEND_SHUTDOWN)
2522 peer_mode |= RCV_SHUTDOWN;
2523 unix_state_lock(other);
2524 other->sk_shutdown |= peer_mode;
2525 unix_state_unlock(other);
2526 other->sk_state_change(other);
2527 if (peer_mode == SHUTDOWN_MASK)
2528 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2529 else if (peer_mode & RCV_SHUTDOWN)
2530 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2531 }
2532 if (other)
2533 sock_put(other);
2534
2535 return 0;
2536}
2537
2538long unix_inq_len(struct sock *sk)
2539{
2540 struct sk_buff *skb;
2541 long amount = 0;
2542
2543 if (sk->sk_state == TCP_LISTEN)
2544 return -EINVAL;
2545
2546 spin_lock(&sk->sk_receive_queue.lock);
2547 if (sk->sk_type == SOCK_STREAM ||
2548 sk->sk_type == SOCK_SEQPACKET) {
2549 skb_queue_walk(&sk->sk_receive_queue, skb)
2550 amount += unix_skb_len(skb);
2551 } else {
2552 skb = skb_peek(&sk->sk_receive_queue);
2553 if (skb)
2554 amount = skb->len;
2555 }
2556 spin_unlock(&sk->sk_receive_queue.lock);
2557
2558 return amount;
2559}
2560EXPORT_SYMBOL_GPL(unix_inq_len);
2561
2562long unix_outq_len(struct sock *sk)
2563{
2564 return sk_wmem_alloc_get(sk);
2565}
2566EXPORT_SYMBOL_GPL(unix_outq_len);
2567
2568static int unix_open_file(struct sock *sk)
2569{
2570 struct path path;
2571 struct file *f;
2572 int fd;
2573
2574 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
2575 return -EPERM;
2576
2577 unix_state_lock(sk);
2578 path = unix_sk(sk)->path;
2579 if (!path.dentry) {
2580 unix_state_unlock(sk);
2581 return -ENOENT;
2582 }
2583
2584 path_get(&path);
2585 unix_state_unlock(sk);
2586
2587 fd = get_unused_fd_flags(O_CLOEXEC);
2588 if (fd < 0)
2589 goto out;
2590
2591 f = dentry_open(&path, O_PATH, current_cred());
2592 if (IS_ERR(f)) {
2593 put_unused_fd(fd);
2594 fd = PTR_ERR(f);
2595 goto out;
2596 }
2597
2598 fd_install(fd, f);
2599out:
2600 path_put(&path);
2601
2602 return fd;
2603}
2604
2605static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2606{
2607 struct sock *sk = sock->sk;
2608 long amount = 0;
2609 int err;
2610
2611 switch (cmd) {
2612 case SIOCOUTQ:
2613 amount = unix_outq_len(sk);
2614 err = put_user(amount, (int __user *)arg);
2615 break;
2616 case SIOCINQ:
2617 amount = unix_inq_len(sk);
2618 if (amount < 0)
2619 err = amount;
2620 else
2621 err = put_user(amount, (int __user *)arg);
2622 break;
2623 case SIOCUNIXFILE:
2624 err = unix_open_file(sk);
2625 break;
2626 default:
2627 err = -ENOIOCTLCMD;
2628 break;
2629 }
2630 return err;
2631}
2632
2633static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2634{
2635 struct sock *sk = sock->sk;
2636 __poll_t mask;
2637
2638 sock_poll_wait(file, sk_sleep(sk), wait);
2639 mask = 0;
2640
2641 /* exceptional events? */
2642 if (sk->sk_err)
2643 mask |= EPOLLERR;
2644 if (sk->sk_shutdown == SHUTDOWN_MASK)
2645 mask |= EPOLLHUP;
2646 if (sk->sk_shutdown & RCV_SHUTDOWN)
2647 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2648
2649 /* readable? */
2650 if (!skb_queue_empty(&sk->sk_receive_queue))
2651 mask |= EPOLLIN | EPOLLRDNORM;
2652
2653 /* Connection-based need to check for termination and startup */
2654 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2655 sk->sk_state == TCP_CLOSE)
2656 mask |= EPOLLHUP;
2657
2658 /*
2659 * we set writable also when the other side has shut down the
2660 * connection. This prevents stuck sockets.
2661 */
2662 if (unix_writable(sk))
2663 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
2664
2665 return mask;
2666}
2667
2668static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
2669 poll_table *wait)
2670{
2671 struct sock *sk = sock->sk, *other;
2672 unsigned int writable;
2673 __poll_t mask;
2674
2675 sock_poll_wait(file, sk_sleep(sk), wait);
2676 mask = 0;
2677
2678 /* exceptional events? */
2679 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2680 mask |= EPOLLERR |
2681 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
2682
2683 if (sk->sk_shutdown & RCV_SHUTDOWN)
2684 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2685 if (sk->sk_shutdown == SHUTDOWN_MASK)
2686 mask |= EPOLLHUP;
2687
2688 /* readable? */
2689 if (!skb_queue_empty(&sk->sk_receive_queue))
2690 mask |= EPOLLIN | EPOLLRDNORM;
2691
2692 /* Connection-based need to check for termination and startup */
2693 if (sk->sk_type == SOCK_SEQPACKET) {
2694 if (sk->sk_state == TCP_CLOSE)
2695 mask |= EPOLLHUP;
2696 /* connection hasn't started yet? */
2697 if (sk->sk_state == TCP_SYN_SENT)
2698 return mask;
2699 }
2700
2701 /* No write status requested, avoid expensive OUT tests. */
2702 if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT)))
2703 return mask;
2704
2705 writable = unix_writable(sk);
2706 if (writable) {
2707 unix_state_lock(sk);
2708
2709 other = unix_peer(sk);
2710 if (other && unix_peer(other) != sk &&
2711 unix_recvq_full(other) &&
2712 unix_dgram_peer_wake_me(sk, other))
2713 writable = 0;
2714
2715 unix_state_unlock(sk);
2716 }
2717
2718 if (writable)
2719 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
2720 else
2721 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2722
2723 return mask;
2724}
2725
2726#ifdef CONFIG_PROC_FS
2727
2728#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2729
2730#define get_bucket(x) ((x) >> BUCKET_SPACE)
2731#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2732#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2733
2734static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2735{
2736 unsigned long offset = get_offset(*pos);
2737 unsigned long bucket = get_bucket(*pos);
2738 struct sock *sk;
2739 unsigned long count = 0;
2740
2741 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2742 if (sock_net(sk) != seq_file_net(seq))
2743 continue;
2744 if (++count == offset)
2745 break;
2746 }
2747
2748 return sk;
2749}
2750
2751static struct sock *unix_next_socket(struct seq_file *seq,
2752 struct sock *sk,
2753 loff_t *pos)
2754{
2755 unsigned long bucket;
2756
2757 while (sk > (struct sock *)SEQ_START_TOKEN) {
2758 sk = sk_next(sk);
2759 if (!sk)
2760 goto next_bucket;
2761 if (sock_net(sk) == seq_file_net(seq))
2762 return sk;
2763 }
2764
2765 do {
2766 sk = unix_from_bucket(seq, pos);
2767 if (sk)
2768 return sk;
2769
2770next_bucket:
2771 bucket = get_bucket(*pos) + 1;
2772 *pos = set_bucket_offset(bucket, 1);
2773 } while (bucket < ARRAY_SIZE(unix_socket_table));
2774
2775 return NULL;
2776}
2777
2778static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2779 __acquires(unix_table_lock)
2780{
2781 spin_lock(&unix_table_lock);
2782
2783 if (!*pos)
2784 return SEQ_START_TOKEN;
2785
2786 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2787 return NULL;
2788
2789 return unix_next_socket(seq, NULL, pos);
2790}
2791
2792static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2793{
2794 ++*pos;
2795 return unix_next_socket(seq, v, pos);
2796}
2797
2798static void unix_seq_stop(struct seq_file *seq, void *v)
2799 __releases(unix_table_lock)
2800{
2801 spin_unlock(&unix_table_lock);
2802}
2803
2804static int unix_seq_show(struct seq_file *seq, void *v)
2805{
2806
2807 if (v == SEQ_START_TOKEN)
2808 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2809 "Inode Path\n");
2810 else {
2811 struct sock *s = v;
2812 struct unix_sock *u = unix_sk(s);
2813 unix_state_lock(s);
2814
2815 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2816 s,
2817 refcount_read(&s->sk_refcnt),
2818 0,
2819 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2820 s->sk_type,
2821 s->sk_socket ?
2822 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2823 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2824 sock_i_ino(s));
2825
2826 if (u->addr) {
2827 int i, len;
2828 seq_putc(seq, ' ');
2829
2830 i = 0;
2831 len = u->addr->len - sizeof(short);
2832 if (!UNIX_ABSTRACT(s))
2833 len--;
2834 else {
2835 seq_putc(seq, '@');
2836 i++;
2837 }
2838 for ( ; i < len; i++)
2839 seq_putc(seq, u->addr->name->sun_path[i] ?:
2840 '@');
2841 }
2842 unix_state_unlock(s);
2843 seq_putc(seq, '\n');
2844 }
2845
2846 return 0;
2847}
2848
2849static const struct seq_operations unix_seq_ops = {
2850 .start = unix_seq_start,
2851 .next = unix_seq_next,
2852 .stop = unix_seq_stop,
2853 .show = unix_seq_show,
2854};
2855
2856static int unix_seq_open(struct inode *inode, struct file *file)
2857{
2858 return seq_open_net(inode, file, &unix_seq_ops,
2859 sizeof(struct seq_net_private));
2860}
2861
2862static const struct file_operations unix_seq_fops = {
2863 .open = unix_seq_open,
2864 .read = seq_read,
2865 .llseek = seq_lseek,
2866 .release = seq_release_net,
2867};
2868
2869#endif
2870
2871static const struct net_proto_family unix_family_ops = {
2872 .family = PF_UNIX,
2873 .create = unix_create,
2874 .owner = THIS_MODULE,
2875};
2876
2877
2878static int __net_init unix_net_init(struct net *net)
2879{
2880 int error = -ENOMEM;
2881
2882 net->unx.sysctl_max_dgram_qlen = 10;
2883 if (unix_sysctl_register(net))
2884 goto out;
2885
2886#ifdef CONFIG_PROC_FS
2887 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2888 unix_sysctl_unregister(net);
2889 goto out;
2890 }
2891#endif
2892 error = 0;
2893out:
2894 return error;
2895}
2896
2897static void __net_exit unix_net_exit(struct net *net)
2898{
2899 unix_sysctl_unregister(net);
2900 remove_proc_entry("unix", net->proc_net);
2901}
2902
2903static struct pernet_operations unix_net_ops = {
2904 .init = unix_net_init,
2905 .exit = unix_net_exit,
2906};
2907
2908static int __init af_unix_init(void)
2909{
2910 int rc = -1;
2911
2912 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2913
2914 rc = proto_register(&unix_proto, 1);
2915 if (rc != 0) {
2916 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
2917 goto out;
2918 }
2919
2920 sock_register(&unix_family_ops);
2921 register_pernet_subsys(&unix_net_ops);
2922out:
2923 return rc;
2924}
2925
2926static void __exit af_unix_exit(void)
2927{
2928 sock_unregister(PF_UNIX);
2929 proto_unregister(&unix_proto);
2930 unregister_pernet_subsys(&unix_net_ops);
2931}
2932
2933/* Earlier than device_initcall() so that other drivers invoking
2934 request_module() don't end up in a loop when modprobe tries
2935 to use a UNIX socket. But later than subsys_initcall() because
2936 we depend on stuff initialised there */
2937fs_initcall(af_unix_init);
2938module_exit(af_unix_exit);
2939
2940MODULE_LICENSE("GPL");
2941MODULE_ALIAS_NETPROTO(PF_UNIX);