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