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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * NET4: Implementation of BSD Unix domain sockets.
4 *
5 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
6 *
7 * Fixes:
8 * Linus Torvalds : Assorted bug cures.
9 * Niibe Yutaka : async I/O support.
10 * Carsten Paeth : PF_UNIX check, address fixes.
11 * Alan Cox : Limit size of allocated blocks.
12 * Alan Cox : Fixed the stupid socketpair bug.
13 * Alan Cox : BSD compatibility fine tuning.
14 * Alan Cox : Fixed a bug in connect when interrupted.
15 * Alan Cox : Sorted out a proper draft version of
16 * file descriptor passing hacked up from
17 * Mike Shaver's work.
18 * Marty Leisner : Fixes to fd passing
19 * Nick Nevin : recvmsg bugfix.
20 * Alan Cox : Started proper garbage collector
21 * Heiko EiBfeldt : Missing verify_area check
22 * Alan Cox : Started POSIXisms
23 * Andreas Schwab : Replace inode by dentry for proper
24 * reference counting
25 * Kirk Petersen : Made this a module
26 * Christoph Rohland : Elegant non-blocking accept/connect algorithm.
27 * Lots of bug fixes.
28 * Alexey Kuznetosv : Repaired (I hope) bugs introduces
29 * by above two patches.
30 * Andrea Arcangeli : If possible we block in connect(2)
31 * if the max backlog of the listen socket
32 * is been reached. This won't break
33 * old apps and it will avoid huge amount
34 * of socks hashed (this for unix_gc()
35 * performances reasons).
36 * Security fix that limits the max
37 * number of socks to 2*max_files and
38 * the number of skb queueable in the
39 * dgram receiver.
40 * Artur Skawina : Hash function optimizations
41 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
42 * Malcolm Beattie : Set peercred for socketpair
43 * Michal Ostrowski : Module initialization cleanup.
44 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT,
45 * the core infrastructure is doing that
46 * for all net proto families now (2.5.69+)
47 *
48 * Known differences from reference BSD that was tested:
49 *
50 * [TO FIX]
51 * ECONNREFUSED is not returned from one end of a connected() socket to the
52 * other the moment one end closes.
53 * fstat() doesn't return st_dev=0, and give the blksize as high water mark
54 * and a fake inode identifier (nor the BSD first socket fstat twice bug).
55 * [NOT TO FIX]
56 * accept() returns a path name even if the connecting socket has closed
57 * in the meantime (BSD loses the path and gives up).
58 * accept() returns 0 length path for an unbound connector. BSD returns 16
59 * and a null first byte in the path (but not for gethost/peername - BSD bug ??)
60 * socketpair(...SOCK_RAW..) doesn't panic the kernel.
61 * BSD af_unix apparently has connect forgetting to block properly.
62 * (need to check this with the POSIX spec in detail)
63 *
64 * Differences from 2.0.0-11-... (ANK)
65 * Bug fixes and improvements.
66 * - client shutdown killed server socket.
67 * - removed all useless cli/sti pairs.
68 *
69 * Semantic changes/extensions.
70 * - generic control message passing.
71 * - SCM_CREDENTIALS control message.
72 * - "Abstract" (not FS based) socket bindings.
73 * Abstract names are sequences of bytes (not zero terminated)
74 * started by 0, so that this name space does not intersect
75 * with BSD names.
76 */
77
78#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
79
80#include <linux/module.h>
81#include <linux/kernel.h>
82#include <linux/signal.h>
83#include <linux/sched/signal.h>
84#include <linux/errno.h>
85#include <linux/string.h>
86#include <linux/stat.h>
87#include <linux/dcache.h>
88#include <linux/namei.h>
89#include <linux/socket.h>
90#include <linux/un.h>
91#include <linux/fcntl.h>
92#include <linux/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
121static atomic_long_t unix_nr_socks;
122static struct hlist_head bsd_socket_buckets[UNIX_HASH_SIZE / 2];
123static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2];
124
125/* SMP locking strategy:
126 * hash table is protected with spinlock.
127 * each socket state is protected by separate spinlock.
128 */
129#ifdef CONFIG_PROVE_LOCKING
130#define cmp_ptr(l, r) (((l) > (r)) - ((l) < (r)))
131
132static int unix_table_lock_cmp_fn(const struct lockdep_map *a,
133 const struct lockdep_map *b)
134{
135 return cmp_ptr(a, b);
136}
137
138static int unix_state_lock_cmp_fn(const struct lockdep_map *_a,
139 const struct lockdep_map *_b)
140{
141 const struct unix_sock *a, *b;
142
143 a = container_of(_a, struct unix_sock, lock.dep_map);
144 b = container_of(_b, struct unix_sock, lock.dep_map);
145
146 if (a->sk.sk_state == TCP_LISTEN) {
147 /* unix_stream_connect(): Before the 2nd unix_state_lock(),
148 *
149 * 1. a is TCP_LISTEN.
150 * 2. b is not a.
151 * 3. concurrent connect(b -> a) must fail.
152 *
153 * Except for 2. & 3., the b's state can be any possible
154 * value due to concurrent connect() or listen().
155 *
156 * 2. is detected in debug_spin_lock_before(), and 3. cannot
157 * be expressed as lock_cmp_fn.
158 */
159 switch (b->sk.sk_state) {
160 case TCP_CLOSE:
161 case TCP_ESTABLISHED:
162 case TCP_LISTEN:
163 return -1;
164 default:
165 /* Invalid case. */
166 return 0;
167 }
168 }
169
170 /* Should never happen. Just to be symmetric. */
171 if (b->sk.sk_state == TCP_LISTEN) {
172 switch (b->sk.sk_state) {
173 case TCP_CLOSE:
174 case TCP_ESTABLISHED:
175 return 1;
176 default:
177 return 0;
178 }
179 }
180
181 /* unix_state_double_lock(): ascending address order. */
182 return cmp_ptr(a, b);
183}
184
185static int unix_recvq_lock_cmp_fn(const struct lockdep_map *_a,
186 const struct lockdep_map *_b)
187{
188 const struct sock *a, *b;
189
190 a = container_of(_a, struct sock, sk_receive_queue.lock.dep_map);
191 b = container_of(_b, struct sock, sk_receive_queue.lock.dep_map);
192
193 /* unix_collect_skb(): listener -> embryo order. */
194 if (a->sk_state == TCP_LISTEN && unix_sk(b)->listener == a)
195 return -1;
196
197 /* Should never happen. Just to be symmetric. */
198 if (b->sk_state == TCP_LISTEN && unix_sk(a)->listener == b)
199 return 1;
200
201 return 0;
202}
203#endif
204
205static unsigned int unix_unbound_hash(struct sock *sk)
206{
207 unsigned long hash = (unsigned long)sk;
208
209 hash ^= hash >> 16;
210 hash ^= hash >> 8;
211 hash ^= sk->sk_type;
212
213 return hash & UNIX_HASH_MOD;
214}
215
216static unsigned int unix_bsd_hash(struct inode *i)
217{
218 return i->i_ino & UNIX_HASH_MOD;
219}
220
221static unsigned int unix_abstract_hash(struct sockaddr_un *sunaddr,
222 int addr_len, int type)
223{
224 __wsum csum = csum_partial(sunaddr, addr_len, 0);
225 unsigned int hash;
226
227 hash = (__force unsigned int)csum_fold(csum);
228 hash ^= hash >> 8;
229 hash ^= type;
230
231 return UNIX_HASH_MOD + 1 + (hash & UNIX_HASH_MOD);
232}
233
234static void unix_table_double_lock(struct net *net,
235 unsigned int hash1, unsigned int hash2)
236{
237 if (hash1 == hash2) {
238 spin_lock(&net->unx.table.locks[hash1]);
239 return;
240 }
241
242 if (hash1 > hash2)
243 swap(hash1, hash2);
244
245 spin_lock(&net->unx.table.locks[hash1]);
246 spin_lock(&net->unx.table.locks[hash2]);
247}
248
249static void unix_table_double_unlock(struct net *net,
250 unsigned int hash1, unsigned int hash2)
251{
252 if (hash1 == hash2) {
253 spin_unlock(&net->unx.table.locks[hash1]);
254 return;
255 }
256
257 spin_unlock(&net->unx.table.locks[hash1]);
258 spin_unlock(&net->unx.table.locks[hash2]);
259}
260
261#ifdef CONFIG_SECURITY_NETWORK
262static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
263{
264 UNIXCB(skb).secid = scm->secid;
265}
266
267static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
268{
269 scm->secid = UNIXCB(skb).secid;
270}
271
272static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
273{
274 return (scm->secid == UNIXCB(skb).secid);
275}
276#else
277static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
278{ }
279
280static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
281{ }
282
283static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
284{
285 return true;
286}
287#endif /* CONFIG_SECURITY_NETWORK */
288
289static inline int unix_our_peer(struct sock *sk, struct sock *osk)
290{
291 return unix_peer(osk) == sk;
292}
293
294static inline int unix_may_send(struct sock *sk, struct sock *osk)
295{
296 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
297}
298
299static inline int unix_recvq_full_lockless(const struct sock *sk)
300{
301 return skb_queue_len_lockless(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
302}
303
304struct sock *unix_peer_get(struct sock *s)
305{
306 struct sock *peer;
307
308 unix_state_lock(s);
309 peer = unix_peer(s);
310 if (peer)
311 sock_hold(peer);
312 unix_state_unlock(s);
313 return peer;
314}
315EXPORT_SYMBOL_GPL(unix_peer_get);
316
317static struct unix_address *unix_create_addr(struct sockaddr_un *sunaddr,
318 int addr_len)
319{
320 struct unix_address *addr;
321
322 addr = kmalloc(sizeof(*addr) + addr_len, GFP_KERNEL);
323 if (!addr)
324 return NULL;
325
326 refcount_set(&addr->refcnt, 1);
327 addr->len = addr_len;
328 memcpy(addr->name, sunaddr, addr_len);
329
330 return addr;
331}
332
333static inline void unix_release_addr(struct unix_address *addr)
334{
335 if (refcount_dec_and_test(&addr->refcnt))
336 kfree(addr);
337}
338
339/*
340 * Check unix socket name:
341 * - should be not zero length.
342 * - if started by not zero, should be NULL terminated (FS object)
343 * - if started by zero, it is abstract name.
344 */
345
346static int unix_validate_addr(struct sockaddr_un *sunaddr, int addr_len)
347{
348 if (addr_len <= offsetof(struct sockaddr_un, sun_path) ||
349 addr_len > sizeof(*sunaddr))
350 return -EINVAL;
351
352 if (sunaddr->sun_family != AF_UNIX)
353 return -EINVAL;
354
355 return 0;
356}
357
358static int unix_mkname_bsd(struct sockaddr_un *sunaddr, int addr_len)
359{
360 struct sockaddr_storage *addr = (struct sockaddr_storage *)sunaddr;
361 short offset = offsetof(struct sockaddr_storage, __data);
362
363 BUILD_BUG_ON(offset != offsetof(struct sockaddr_un, sun_path));
364
365 /* This may look like an off by one error but it is a bit more
366 * subtle. 108 is the longest valid AF_UNIX path for a binding.
367 * sun_path[108] doesn't as such exist. However in kernel space
368 * we are guaranteed that it is a valid memory location in our
369 * kernel address buffer because syscall functions always pass
370 * a pointer of struct sockaddr_storage which has a bigger buffer
371 * than 108. Also, we must terminate sun_path for strlen() in
372 * getname_kernel().
373 */
374 addr->__data[addr_len - offset] = 0;
375
376 /* Don't pass sunaddr->sun_path to strlen(). Otherwise, 108 will
377 * cause panic if CONFIG_FORTIFY_SOURCE=y. Let __fortify_strlen()
378 * know the actual buffer.
379 */
380 return strlen(addr->__data) + offset + 1;
381}
382
383static void __unix_remove_socket(struct sock *sk)
384{
385 sk_del_node_init(sk);
386}
387
388static void __unix_insert_socket(struct net *net, struct sock *sk)
389{
390 DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk));
391 sk_add_node(sk, &net->unx.table.buckets[sk->sk_hash]);
392}
393
394static void __unix_set_addr_hash(struct net *net, struct sock *sk,
395 struct unix_address *addr, unsigned int hash)
396{
397 __unix_remove_socket(sk);
398 smp_store_release(&unix_sk(sk)->addr, addr);
399
400 sk->sk_hash = hash;
401 __unix_insert_socket(net, sk);
402}
403
404static void unix_remove_socket(struct net *net, struct sock *sk)
405{
406 spin_lock(&net->unx.table.locks[sk->sk_hash]);
407 __unix_remove_socket(sk);
408 spin_unlock(&net->unx.table.locks[sk->sk_hash]);
409}
410
411static void unix_insert_unbound_socket(struct net *net, struct sock *sk)
412{
413 spin_lock(&net->unx.table.locks[sk->sk_hash]);
414 __unix_insert_socket(net, sk);
415 spin_unlock(&net->unx.table.locks[sk->sk_hash]);
416}
417
418static void unix_insert_bsd_socket(struct sock *sk)
419{
420 spin_lock(&bsd_socket_locks[sk->sk_hash]);
421 sk_add_bind_node(sk, &bsd_socket_buckets[sk->sk_hash]);
422 spin_unlock(&bsd_socket_locks[sk->sk_hash]);
423}
424
425static void unix_remove_bsd_socket(struct sock *sk)
426{
427 if (!hlist_unhashed(&sk->sk_bind_node)) {
428 spin_lock(&bsd_socket_locks[sk->sk_hash]);
429 __sk_del_bind_node(sk);
430 spin_unlock(&bsd_socket_locks[sk->sk_hash]);
431
432 sk_node_init(&sk->sk_bind_node);
433 }
434}
435
436static struct sock *__unix_find_socket_byname(struct net *net,
437 struct sockaddr_un *sunname,
438 int len, unsigned int hash)
439{
440 struct sock *s;
441
442 sk_for_each(s, &net->unx.table.buckets[hash]) {
443 struct unix_sock *u = unix_sk(s);
444
445 if (u->addr->len == len &&
446 !memcmp(u->addr->name, sunname, len))
447 return s;
448 }
449 return NULL;
450}
451
452static inline struct sock *unix_find_socket_byname(struct net *net,
453 struct sockaddr_un *sunname,
454 int len, unsigned int hash)
455{
456 struct sock *s;
457
458 spin_lock(&net->unx.table.locks[hash]);
459 s = __unix_find_socket_byname(net, sunname, len, hash);
460 if (s)
461 sock_hold(s);
462 spin_unlock(&net->unx.table.locks[hash]);
463 return s;
464}
465
466static struct sock *unix_find_socket_byinode(struct inode *i)
467{
468 unsigned int hash = unix_bsd_hash(i);
469 struct sock *s;
470
471 spin_lock(&bsd_socket_locks[hash]);
472 sk_for_each_bound(s, &bsd_socket_buckets[hash]) {
473 struct dentry *dentry = unix_sk(s)->path.dentry;
474
475 if (dentry && d_backing_inode(dentry) == i) {
476 sock_hold(s);
477 spin_unlock(&bsd_socket_locks[hash]);
478 return s;
479 }
480 }
481 spin_unlock(&bsd_socket_locks[hash]);
482 return NULL;
483}
484
485/* Support code for asymmetrically connected dgram sockets
486 *
487 * If a datagram socket is connected to a socket not itself connected
488 * to the first socket (eg, /dev/log), clients may only enqueue more
489 * messages if the present receive queue of the server socket is not
490 * "too large". This means there's a second writeability condition
491 * poll and sendmsg need to test. The dgram recv code will do a wake
492 * up on the peer_wait wait queue of a socket upon reception of a
493 * datagram which needs to be propagated to sleeping would-be writers
494 * since these might not have sent anything so far. This can't be
495 * accomplished via poll_wait because the lifetime of the server
496 * socket might be less than that of its clients if these break their
497 * association with it or if the server socket is closed while clients
498 * are still connected to it and there's no way to inform "a polling
499 * implementation" that it should let go of a certain wait queue
500 *
501 * In order to propagate a wake up, a wait_queue_entry_t of the client
502 * socket is enqueued on the peer_wait queue of the server socket
503 * whose wake function does a wake_up on the ordinary client socket
504 * wait queue. This connection is established whenever a write (or
505 * poll for write) hit the flow control condition and broken when the
506 * association to the server socket is dissolved or after a wake up
507 * was relayed.
508 */
509
510static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
511 void *key)
512{
513 struct unix_sock *u;
514 wait_queue_head_t *u_sleep;
515
516 u = container_of(q, struct unix_sock, peer_wake);
517
518 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
519 q);
520 u->peer_wake.private = NULL;
521
522 /* relaying can only happen while the wq still exists */
523 u_sleep = sk_sleep(&u->sk);
524 if (u_sleep)
525 wake_up_interruptible_poll(u_sleep, key_to_poll(key));
526
527 return 0;
528}
529
530static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
531{
532 struct unix_sock *u, *u_other;
533 int rc;
534
535 u = unix_sk(sk);
536 u_other = unix_sk(other);
537 rc = 0;
538 spin_lock(&u_other->peer_wait.lock);
539
540 if (!u->peer_wake.private) {
541 u->peer_wake.private = other;
542 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
543
544 rc = 1;
545 }
546
547 spin_unlock(&u_other->peer_wait.lock);
548 return rc;
549}
550
551static void unix_dgram_peer_wake_disconnect(struct sock *sk,
552 struct sock *other)
553{
554 struct unix_sock *u, *u_other;
555
556 u = unix_sk(sk);
557 u_other = unix_sk(other);
558 spin_lock(&u_other->peer_wait.lock);
559
560 if (u->peer_wake.private == other) {
561 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
562 u->peer_wake.private = NULL;
563 }
564
565 spin_unlock(&u_other->peer_wait.lock);
566}
567
568static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
569 struct sock *other)
570{
571 unix_dgram_peer_wake_disconnect(sk, other);
572 wake_up_interruptible_poll(sk_sleep(sk),
573 EPOLLOUT |
574 EPOLLWRNORM |
575 EPOLLWRBAND);
576}
577
578/* preconditions:
579 * - unix_peer(sk) == other
580 * - association is stable
581 */
582static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
583{
584 int connected;
585
586 connected = unix_dgram_peer_wake_connect(sk, other);
587
588 /* If other is SOCK_DEAD, we want to make sure we signal
589 * POLLOUT, such that a subsequent write() can get a
590 * -ECONNREFUSED. Otherwise, if we haven't queued any skbs
591 * to other and its full, we will hang waiting for POLLOUT.
592 */
593 if (unix_recvq_full_lockless(other) && !sock_flag(other, SOCK_DEAD))
594 return 1;
595
596 if (connected)
597 unix_dgram_peer_wake_disconnect(sk, other);
598
599 return 0;
600}
601
602static int unix_writable(const struct sock *sk, unsigned char state)
603{
604 return state != TCP_LISTEN &&
605 (refcount_read(&sk->sk_wmem_alloc) << 2) <= READ_ONCE(sk->sk_sndbuf);
606}
607
608static void unix_write_space(struct sock *sk)
609{
610 struct socket_wq *wq;
611
612 rcu_read_lock();
613 if (unix_writable(sk, READ_ONCE(sk->sk_state))) {
614 wq = rcu_dereference(sk->sk_wq);
615 if (skwq_has_sleeper(wq))
616 wake_up_interruptible_sync_poll(&wq->wait,
617 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
618 sk_wake_async_rcu(sk, SOCK_WAKE_SPACE, POLL_OUT);
619 }
620 rcu_read_unlock();
621}
622
623/* When dgram socket disconnects (or changes its peer), we clear its receive
624 * queue of packets arrived from previous peer. First, it allows to do
625 * flow control based only on wmem_alloc; second, sk connected to peer
626 * may receive messages only from that peer. */
627static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
628{
629 if (!skb_queue_empty(&sk->sk_receive_queue)) {
630 skb_queue_purge(&sk->sk_receive_queue);
631 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
632
633 /* If one link of bidirectional dgram pipe is disconnected,
634 * we signal error. Messages are lost. Do not make this,
635 * when peer was not connected to us.
636 */
637 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
638 WRITE_ONCE(other->sk_err, ECONNRESET);
639 sk_error_report(other);
640 }
641 }
642}
643
644static void unix_sock_destructor(struct sock *sk)
645{
646 struct unix_sock *u = unix_sk(sk);
647
648 skb_queue_purge(&sk->sk_receive_queue);
649
650 DEBUG_NET_WARN_ON_ONCE(refcount_read(&sk->sk_wmem_alloc));
651 DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk));
652 DEBUG_NET_WARN_ON_ONCE(sk->sk_socket);
653 if (!sock_flag(sk, SOCK_DEAD)) {
654 pr_info("Attempt to release alive unix socket: %p\n", sk);
655 return;
656 }
657
658 if (u->addr)
659 unix_release_addr(u->addr);
660
661 atomic_long_dec(&unix_nr_socks);
662 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
663#ifdef UNIX_REFCNT_DEBUG
664 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
665 atomic_long_read(&unix_nr_socks));
666#endif
667}
668
669static void unix_release_sock(struct sock *sk, int embrion)
670{
671 struct unix_sock *u = unix_sk(sk);
672 struct sock *skpair;
673 struct sk_buff *skb;
674 struct path path;
675 int state;
676
677 unix_remove_socket(sock_net(sk), sk);
678 unix_remove_bsd_socket(sk);
679
680 /* Clear state */
681 unix_state_lock(sk);
682 sock_orphan(sk);
683 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
684 path = u->path;
685 u->path.dentry = NULL;
686 u->path.mnt = NULL;
687 state = sk->sk_state;
688 WRITE_ONCE(sk->sk_state, TCP_CLOSE);
689
690 skpair = unix_peer(sk);
691 unix_peer(sk) = NULL;
692
693 unix_state_unlock(sk);
694
695#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
696 u->oob_skb = NULL;
697#endif
698
699 wake_up_interruptible_all(&u->peer_wait);
700
701 if (skpair != NULL) {
702 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
703 unix_state_lock(skpair);
704 /* No more writes */
705 WRITE_ONCE(skpair->sk_shutdown, SHUTDOWN_MASK);
706 if (!skb_queue_empty_lockless(&sk->sk_receive_queue) || embrion)
707 WRITE_ONCE(skpair->sk_err, ECONNRESET);
708 unix_state_unlock(skpair);
709 skpair->sk_state_change(skpair);
710 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
711 }
712
713 unix_dgram_peer_wake_disconnect(sk, skpair);
714 sock_put(skpair); /* It may now die */
715 }
716
717 /* Try to flush out this socket. Throw out buffers at least */
718
719 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
720 if (state == TCP_LISTEN)
721 unix_release_sock(skb->sk, 1);
722
723 /* passed fds are erased in the kfree_skb hook */
724 kfree_skb(skb);
725 }
726
727 if (path.dentry)
728 path_put(&path);
729
730 sock_put(sk);
731
732 /* ---- Socket is dead now and most probably destroyed ---- */
733
734 /*
735 * Fixme: BSD difference: In BSD all sockets connected to us get
736 * ECONNRESET and we die on the spot. In Linux we behave
737 * like files and pipes do and wait for the last
738 * dereference.
739 *
740 * Can't we simply set sock->err?
741 *
742 * What the above comment does talk about? --ANK(980817)
743 */
744
745 if (READ_ONCE(unix_tot_inflight))
746 unix_gc(); /* Garbage collect fds */
747}
748
749static void init_peercred(struct sock *sk)
750{
751 sk->sk_peer_pid = get_pid(task_tgid(current));
752 sk->sk_peer_cred = get_current_cred();
753}
754
755static void update_peercred(struct sock *sk)
756{
757 const struct cred *old_cred;
758 struct pid *old_pid;
759
760 spin_lock(&sk->sk_peer_lock);
761 old_pid = sk->sk_peer_pid;
762 old_cred = sk->sk_peer_cred;
763 init_peercred(sk);
764 spin_unlock(&sk->sk_peer_lock);
765
766 put_pid(old_pid);
767 put_cred(old_cred);
768}
769
770static void copy_peercred(struct sock *sk, struct sock *peersk)
771{
772 lockdep_assert_held(&unix_sk(peersk)->lock);
773
774 spin_lock(&sk->sk_peer_lock);
775 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
776 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
777 spin_unlock(&sk->sk_peer_lock);
778}
779
780static int unix_listen(struct socket *sock, int backlog)
781{
782 int err;
783 struct sock *sk = sock->sk;
784 struct unix_sock *u = unix_sk(sk);
785
786 err = -EOPNOTSUPP;
787 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
788 goto out; /* Only stream/seqpacket sockets accept */
789 err = -EINVAL;
790 if (!READ_ONCE(u->addr))
791 goto out; /* No listens on an unbound socket */
792 unix_state_lock(sk);
793 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
794 goto out_unlock;
795 if (backlog > sk->sk_max_ack_backlog)
796 wake_up_interruptible_all(&u->peer_wait);
797 sk->sk_max_ack_backlog = backlog;
798 WRITE_ONCE(sk->sk_state, TCP_LISTEN);
799
800 /* set credentials so connect can copy them */
801 update_peercred(sk);
802 err = 0;
803
804out_unlock:
805 unix_state_unlock(sk);
806out:
807 return err;
808}
809
810static int unix_release(struct socket *);
811static int unix_bind(struct socket *, struct sockaddr *, int);
812static int unix_stream_connect(struct socket *, struct sockaddr *,
813 int addr_len, int flags);
814static int unix_socketpair(struct socket *, struct socket *);
815static int unix_accept(struct socket *, struct socket *, struct proto_accept_arg *arg);
816static int unix_getname(struct socket *, struct sockaddr *, int);
817static __poll_t unix_poll(struct file *, struct socket *, poll_table *);
818static __poll_t unix_dgram_poll(struct file *, struct socket *,
819 poll_table *);
820static int unix_ioctl(struct socket *, unsigned int, unsigned long);
821#ifdef CONFIG_COMPAT
822static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
823#endif
824static int unix_shutdown(struct socket *, int);
825static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
826static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
827static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
828 struct pipe_inode_info *, size_t size,
829 unsigned int flags);
830static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
831static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
832static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
833static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
834static int unix_dgram_connect(struct socket *, struct sockaddr *,
835 int, int);
836static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
837static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
838 int);
839
840#ifdef CONFIG_PROC_FS
841static int unix_count_nr_fds(struct sock *sk)
842{
843 struct sk_buff *skb;
844 struct unix_sock *u;
845 int nr_fds = 0;
846
847 spin_lock(&sk->sk_receive_queue.lock);
848 skb = skb_peek(&sk->sk_receive_queue);
849 while (skb) {
850 u = unix_sk(skb->sk);
851 nr_fds += atomic_read(&u->scm_stat.nr_fds);
852 skb = skb_peek_next(skb, &sk->sk_receive_queue);
853 }
854 spin_unlock(&sk->sk_receive_queue.lock);
855
856 return nr_fds;
857}
858
859static void unix_show_fdinfo(struct seq_file *m, struct socket *sock)
860{
861 struct sock *sk = sock->sk;
862 unsigned char s_state;
863 struct unix_sock *u;
864 int nr_fds = 0;
865
866 if (sk) {
867 s_state = READ_ONCE(sk->sk_state);
868 u = unix_sk(sk);
869
870 /* SOCK_STREAM and SOCK_SEQPACKET sockets never change their
871 * sk_state after switching to TCP_ESTABLISHED or TCP_LISTEN.
872 * SOCK_DGRAM is ordinary. So, no lock is needed.
873 */
874 if (sock->type == SOCK_DGRAM || s_state == TCP_ESTABLISHED)
875 nr_fds = atomic_read(&u->scm_stat.nr_fds);
876 else if (s_state == TCP_LISTEN)
877 nr_fds = unix_count_nr_fds(sk);
878
879 seq_printf(m, "scm_fds: %u\n", nr_fds);
880 }
881}
882#else
883#define unix_show_fdinfo NULL
884#endif
885
886static const struct proto_ops unix_stream_ops = {
887 .family = PF_UNIX,
888 .owner = THIS_MODULE,
889 .release = unix_release,
890 .bind = unix_bind,
891 .connect = unix_stream_connect,
892 .socketpair = unix_socketpair,
893 .accept = unix_accept,
894 .getname = unix_getname,
895 .poll = unix_poll,
896 .ioctl = unix_ioctl,
897#ifdef CONFIG_COMPAT
898 .compat_ioctl = unix_compat_ioctl,
899#endif
900 .listen = unix_listen,
901 .shutdown = unix_shutdown,
902 .sendmsg = unix_stream_sendmsg,
903 .recvmsg = unix_stream_recvmsg,
904 .read_skb = unix_stream_read_skb,
905 .mmap = sock_no_mmap,
906 .splice_read = unix_stream_splice_read,
907 .set_peek_off = sk_set_peek_off,
908 .show_fdinfo = unix_show_fdinfo,
909};
910
911static const struct proto_ops unix_dgram_ops = {
912 .family = PF_UNIX,
913 .owner = THIS_MODULE,
914 .release = unix_release,
915 .bind = unix_bind,
916 .connect = unix_dgram_connect,
917 .socketpair = unix_socketpair,
918 .accept = sock_no_accept,
919 .getname = unix_getname,
920 .poll = unix_dgram_poll,
921 .ioctl = unix_ioctl,
922#ifdef CONFIG_COMPAT
923 .compat_ioctl = unix_compat_ioctl,
924#endif
925 .listen = sock_no_listen,
926 .shutdown = unix_shutdown,
927 .sendmsg = unix_dgram_sendmsg,
928 .read_skb = unix_read_skb,
929 .recvmsg = unix_dgram_recvmsg,
930 .mmap = sock_no_mmap,
931 .set_peek_off = sk_set_peek_off,
932 .show_fdinfo = unix_show_fdinfo,
933};
934
935static const struct proto_ops unix_seqpacket_ops = {
936 .family = PF_UNIX,
937 .owner = THIS_MODULE,
938 .release = unix_release,
939 .bind = unix_bind,
940 .connect = unix_stream_connect,
941 .socketpair = unix_socketpair,
942 .accept = unix_accept,
943 .getname = unix_getname,
944 .poll = unix_dgram_poll,
945 .ioctl = unix_ioctl,
946#ifdef CONFIG_COMPAT
947 .compat_ioctl = unix_compat_ioctl,
948#endif
949 .listen = unix_listen,
950 .shutdown = unix_shutdown,
951 .sendmsg = unix_seqpacket_sendmsg,
952 .recvmsg = unix_seqpacket_recvmsg,
953 .mmap = sock_no_mmap,
954 .set_peek_off = sk_set_peek_off,
955 .show_fdinfo = unix_show_fdinfo,
956};
957
958static void unix_close(struct sock *sk, long timeout)
959{
960 /* Nothing to do here, unix socket does not need a ->close().
961 * This is merely for sockmap.
962 */
963}
964
965static void unix_unhash(struct sock *sk)
966{
967 /* Nothing to do here, unix socket does not need a ->unhash().
968 * This is merely for sockmap.
969 */
970}
971
972static bool unix_bpf_bypass_getsockopt(int level, int optname)
973{
974 if (level == SOL_SOCKET) {
975 switch (optname) {
976 case SO_PEERPIDFD:
977 return true;
978 default:
979 return false;
980 }
981 }
982
983 return false;
984}
985
986struct proto unix_dgram_proto = {
987 .name = "UNIX",
988 .owner = THIS_MODULE,
989 .obj_size = sizeof(struct unix_sock),
990 .close = unix_close,
991 .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt,
992#ifdef CONFIG_BPF_SYSCALL
993 .psock_update_sk_prot = unix_dgram_bpf_update_proto,
994#endif
995};
996
997struct proto unix_stream_proto = {
998 .name = "UNIX-STREAM",
999 .owner = THIS_MODULE,
1000 .obj_size = sizeof(struct unix_sock),
1001 .close = unix_close,
1002 .unhash = unix_unhash,
1003 .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt,
1004#ifdef CONFIG_BPF_SYSCALL
1005 .psock_update_sk_prot = unix_stream_bpf_update_proto,
1006#endif
1007};
1008
1009static struct sock *unix_create1(struct net *net, struct socket *sock, int kern, int type)
1010{
1011 struct unix_sock *u;
1012 struct sock *sk;
1013 int err;
1014
1015 atomic_long_inc(&unix_nr_socks);
1016 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) {
1017 err = -ENFILE;
1018 goto err;
1019 }
1020
1021 if (type == SOCK_STREAM)
1022 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_stream_proto, kern);
1023 else /*dgram and seqpacket */
1024 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_dgram_proto, kern);
1025
1026 if (!sk) {
1027 err = -ENOMEM;
1028 goto err;
1029 }
1030
1031 sock_init_data(sock, sk);
1032
1033 sk->sk_hash = unix_unbound_hash(sk);
1034 sk->sk_allocation = GFP_KERNEL_ACCOUNT;
1035 sk->sk_write_space = unix_write_space;
1036 sk->sk_max_ack_backlog = READ_ONCE(net->unx.sysctl_max_dgram_qlen);
1037 sk->sk_destruct = unix_sock_destructor;
1038 lock_set_cmp_fn(&sk->sk_receive_queue.lock, unix_recvq_lock_cmp_fn, NULL);
1039
1040 u = unix_sk(sk);
1041 u->listener = NULL;
1042 u->vertex = NULL;
1043 u->path.dentry = NULL;
1044 u->path.mnt = NULL;
1045 spin_lock_init(&u->lock);
1046 lock_set_cmp_fn(&u->lock, unix_state_lock_cmp_fn, NULL);
1047 mutex_init(&u->iolock); /* single task reading lock */
1048 mutex_init(&u->bindlock); /* single task binding lock */
1049 init_waitqueue_head(&u->peer_wait);
1050 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
1051 memset(&u->scm_stat, 0, sizeof(struct scm_stat));
1052 unix_insert_unbound_socket(net, sk);
1053
1054 sock_prot_inuse_add(net, sk->sk_prot, 1);
1055
1056 return sk;
1057
1058err:
1059 atomic_long_dec(&unix_nr_socks);
1060 return ERR_PTR(err);
1061}
1062
1063static int unix_create(struct net *net, struct socket *sock, int protocol,
1064 int kern)
1065{
1066 struct sock *sk;
1067
1068 if (protocol && protocol != PF_UNIX)
1069 return -EPROTONOSUPPORT;
1070
1071 sock->state = SS_UNCONNECTED;
1072
1073 switch (sock->type) {
1074 case SOCK_STREAM:
1075 sock->ops = &unix_stream_ops;
1076 break;
1077 /*
1078 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
1079 * nothing uses it.
1080 */
1081 case SOCK_RAW:
1082 sock->type = SOCK_DGRAM;
1083 fallthrough;
1084 case SOCK_DGRAM:
1085 sock->ops = &unix_dgram_ops;
1086 break;
1087 case SOCK_SEQPACKET:
1088 sock->ops = &unix_seqpacket_ops;
1089 break;
1090 default:
1091 return -ESOCKTNOSUPPORT;
1092 }
1093
1094 sk = unix_create1(net, sock, kern, sock->type);
1095 if (IS_ERR(sk))
1096 return PTR_ERR(sk);
1097
1098 return 0;
1099}
1100
1101static int unix_release(struct socket *sock)
1102{
1103 struct sock *sk = sock->sk;
1104
1105 if (!sk)
1106 return 0;
1107
1108 sk->sk_prot->close(sk, 0);
1109 unix_release_sock(sk, 0);
1110 sock->sk = NULL;
1111
1112 return 0;
1113}
1114
1115static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len,
1116 int type)
1117{
1118 struct inode *inode;
1119 struct path path;
1120 struct sock *sk;
1121 int err;
1122
1123 unix_mkname_bsd(sunaddr, addr_len);
1124 err = kern_path(sunaddr->sun_path, LOOKUP_FOLLOW, &path);
1125 if (err)
1126 goto fail;
1127
1128 err = path_permission(&path, MAY_WRITE);
1129 if (err)
1130 goto path_put;
1131
1132 err = -ECONNREFUSED;
1133 inode = d_backing_inode(path.dentry);
1134 if (!S_ISSOCK(inode->i_mode))
1135 goto path_put;
1136
1137 sk = unix_find_socket_byinode(inode);
1138 if (!sk)
1139 goto path_put;
1140
1141 err = -EPROTOTYPE;
1142 if (sk->sk_type == type)
1143 touch_atime(&path);
1144 else
1145 goto sock_put;
1146
1147 path_put(&path);
1148
1149 return sk;
1150
1151sock_put:
1152 sock_put(sk);
1153path_put:
1154 path_put(&path);
1155fail:
1156 return ERR_PTR(err);
1157}
1158
1159static struct sock *unix_find_abstract(struct net *net,
1160 struct sockaddr_un *sunaddr,
1161 int addr_len, int type)
1162{
1163 unsigned int hash = unix_abstract_hash(sunaddr, addr_len, type);
1164 struct dentry *dentry;
1165 struct sock *sk;
1166
1167 sk = unix_find_socket_byname(net, sunaddr, addr_len, hash);
1168 if (!sk)
1169 return ERR_PTR(-ECONNREFUSED);
1170
1171 dentry = unix_sk(sk)->path.dentry;
1172 if (dentry)
1173 touch_atime(&unix_sk(sk)->path);
1174
1175 return sk;
1176}
1177
1178static struct sock *unix_find_other(struct net *net,
1179 struct sockaddr_un *sunaddr,
1180 int addr_len, int type)
1181{
1182 struct sock *sk;
1183
1184 if (sunaddr->sun_path[0])
1185 sk = unix_find_bsd(sunaddr, addr_len, type);
1186 else
1187 sk = unix_find_abstract(net, sunaddr, addr_len, type);
1188
1189 return sk;
1190}
1191
1192static int unix_autobind(struct sock *sk)
1193{
1194 struct unix_sock *u = unix_sk(sk);
1195 unsigned int new_hash, old_hash;
1196 struct net *net = sock_net(sk);
1197 struct unix_address *addr;
1198 u32 lastnum, ordernum;
1199 int err;
1200
1201 err = mutex_lock_interruptible(&u->bindlock);
1202 if (err)
1203 return err;
1204
1205 if (u->addr)
1206 goto out;
1207
1208 err = -ENOMEM;
1209 addr = kzalloc(sizeof(*addr) +
1210 offsetof(struct sockaddr_un, sun_path) + 16, GFP_KERNEL);
1211 if (!addr)
1212 goto out;
1213
1214 addr->len = offsetof(struct sockaddr_un, sun_path) + 6;
1215 addr->name->sun_family = AF_UNIX;
1216 refcount_set(&addr->refcnt, 1);
1217
1218 old_hash = sk->sk_hash;
1219 ordernum = get_random_u32();
1220 lastnum = ordernum & 0xFFFFF;
1221retry:
1222 ordernum = (ordernum + 1) & 0xFFFFF;
1223 sprintf(addr->name->sun_path + 1, "%05x", ordernum);
1224
1225 new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);
1226 unix_table_double_lock(net, old_hash, new_hash);
1227
1228 if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) {
1229 unix_table_double_unlock(net, old_hash, new_hash);
1230
1231 /* __unix_find_socket_byname() may take long time if many names
1232 * are already in use.
1233 */
1234 cond_resched();
1235
1236 if (ordernum == lastnum) {
1237 /* Give up if all names seems to be in use. */
1238 err = -ENOSPC;
1239 unix_release_addr(addr);
1240 goto out;
1241 }
1242
1243 goto retry;
1244 }
1245
1246 __unix_set_addr_hash(net, sk, addr, new_hash);
1247 unix_table_double_unlock(net, old_hash, new_hash);
1248 err = 0;
1249
1250out: mutex_unlock(&u->bindlock);
1251 return err;
1252}
1253
1254static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr,
1255 int addr_len)
1256{
1257 umode_t mode = S_IFSOCK |
1258 (SOCK_INODE(sk->sk_socket)->i_mode & ~current_umask());
1259 struct unix_sock *u = unix_sk(sk);
1260 unsigned int new_hash, old_hash;
1261 struct net *net = sock_net(sk);
1262 struct mnt_idmap *idmap;
1263 struct unix_address *addr;
1264 struct dentry *dentry;
1265 struct path parent;
1266 int err;
1267
1268 addr_len = unix_mkname_bsd(sunaddr, addr_len);
1269 addr = unix_create_addr(sunaddr, addr_len);
1270 if (!addr)
1271 return -ENOMEM;
1272
1273 /*
1274 * Get the parent directory, calculate the hash for last
1275 * component.
1276 */
1277 dentry = kern_path_create(AT_FDCWD, addr->name->sun_path, &parent, 0);
1278 if (IS_ERR(dentry)) {
1279 err = PTR_ERR(dentry);
1280 goto out;
1281 }
1282
1283 /*
1284 * All right, let's create it.
1285 */
1286 idmap = mnt_idmap(parent.mnt);
1287 err = security_path_mknod(&parent, dentry, mode, 0);
1288 if (!err)
1289 err = vfs_mknod(idmap, d_inode(parent.dentry), dentry, mode, 0);
1290 if (err)
1291 goto out_path;
1292 err = mutex_lock_interruptible(&u->bindlock);
1293 if (err)
1294 goto out_unlink;
1295 if (u->addr)
1296 goto out_unlock;
1297
1298 old_hash = sk->sk_hash;
1299 new_hash = unix_bsd_hash(d_backing_inode(dentry));
1300 unix_table_double_lock(net, old_hash, new_hash);
1301 u->path.mnt = mntget(parent.mnt);
1302 u->path.dentry = dget(dentry);
1303 __unix_set_addr_hash(net, sk, addr, new_hash);
1304 unix_table_double_unlock(net, old_hash, new_hash);
1305 unix_insert_bsd_socket(sk);
1306 mutex_unlock(&u->bindlock);
1307 done_path_create(&parent, dentry);
1308 return 0;
1309
1310out_unlock:
1311 mutex_unlock(&u->bindlock);
1312 err = -EINVAL;
1313out_unlink:
1314 /* failed after successful mknod? unlink what we'd created... */
1315 vfs_unlink(idmap, d_inode(parent.dentry), dentry, NULL);
1316out_path:
1317 done_path_create(&parent, dentry);
1318out:
1319 unix_release_addr(addr);
1320 return err == -EEXIST ? -EADDRINUSE : err;
1321}
1322
1323static int unix_bind_abstract(struct sock *sk, struct sockaddr_un *sunaddr,
1324 int addr_len)
1325{
1326 struct unix_sock *u = unix_sk(sk);
1327 unsigned int new_hash, old_hash;
1328 struct net *net = sock_net(sk);
1329 struct unix_address *addr;
1330 int err;
1331
1332 addr = unix_create_addr(sunaddr, addr_len);
1333 if (!addr)
1334 return -ENOMEM;
1335
1336 err = mutex_lock_interruptible(&u->bindlock);
1337 if (err)
1338 goto out;
1339
1340 if (u->addr) {
1341 err = -EINVAL;
1342 goto out_mutex;
1343 }
1344
1345 old_hash = sk->sk_hash;
1346 new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);
1347 unix_table_double_lock(net, old_hash, new_hash);
1348
1349 if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash))
1350 goto out_spin;
1351
1352 __unix_set_addr_hash(net, sk, addr, new_hash);
1353 unix_table_double_unlock(net, old_hash, new_hash);
1354 mutex_unlock(&u->bindlock);
1355 return 0;
1356
1357out_spin:
1358 unix_table_double_unlock(net, old_hash, new_hash);
1359 err = -EADDRINUSE;
1360out_mutex:
1361 mutex_unlock(&u->bindlock);
1362out:
1363 unix_release_addr(addr);
1364 return err;
1365}
1366
1367static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1368{
1369 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1370 struct sock *sk = sock->sk;
1371 int err;
1372
1373 if (addr_len == offsetof(struct sockaddr_un, sun_path) &&
1374 sunaddr->sun_family == AF_UNIX)
1375 return unix_autobind(sk);
1376
1377 err = unix_validate_addr(sunaddr, addr_len);
1378 if (err)
1379 return err;
1380
1381 if (sunaddr->sun_path[0])
1382 err = unix_bind_bsd(sk, sunaddr, addr_len);
1383 else
1384 err = unix_bind_abstract(sk, sunaddr, addr_len);
1385
1386 return err;
1387}
1388
1389static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1390{
1391 if (unlikely(sk1 == sk2) || !sk2) {
1392 unix_state_lock(sk1);
1393 return;
1394 }
1395
1396 if (sk1 > sk2)
1397 swap(sk1, sk2);
1398
1399 unix_state_lock(sk1);
1400 unix_state_lock(sk2);
1401}
1402
1403static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1404{
1405 if (unlikely(sk1 == sk2) || !sk2) {
1406 unix_state_unlock(sk1);
1407 return;
1408 }
1409 unix_state_unlock(sk1);
1410 unix_state_unlock(sk2);
1411}
1412
1413static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1414 int alen, int flags)
1415{
1416 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1417 struct sock *sk = sock->sk;
1418 struct sock *other;
1419 int err;
1420
1421 err = -EINVAL;
1422 if (alen < offsetofend(struct sockaddr, sa_family))
1423 goto out;
1424
1425 if (addr->sa_family != AF_UNSPEC) {
1426 err = unix_validate_addr(sunaddr, alen);
1427 if (err)
1428 goto out;
1429
1430 err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, addr, &alen);
1431 if (err)
1432 goto out;
1433
1434 if ((test_bit(SOCK_PASSCRED, &sock->flags) ||
1435 test_bit(SOCK_PASSPIDFD, &sock->flags)) &&
1436 !READ_ONCE(unix_sk(sk)->addr)) {
1437 err = unix_autobind(sk);
1438 if (err)
1439 goto out;
1440 }
1441
1442restart:
1443 other = unix_find_other(sock_net(sk), sunaddr, alen, sock->type);
1444 if (IS_ERR(other)) {
1445 err = PTR_ERR(other);
1446 goto out;
1447 }
1448
1449 unix_state_double_lock(sk, other);
1450
1451 /* Apparently VFS overslept socket death. Retry. */
1452 if (sock_flag(other, SOCK_DEAD)) {
1453 unix_state_double_unlock(sk, other);
1454 sock_put(other);
1455 goto restart;
1456 }
1457
1458 err = -EPERM;
1459 if (!unix_may_send(sk, other))
1460 goto out_unlock;
1461
1462 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1463 if (err)
1464 goto out_unlock;
1465
1466 WRITE_ONCE(sk->sk_state, TCP_ESTABLISHED);
1467 WRITE_ONCE(other->sk_state, TCP_ESTABLISHED);
1468 } else {
1469 /*
1470 * 1003.1g breaking connected state with AF_UNSPEC
1471 */
1472 other = NULL;
1473 unix_state_double_lock(sk, other);
1474 }
1475
1476 /*
1477 * If it was connected, reconnect.
1478 */
1479 if (unix_peer(sk)) {
1480 struct sock *old_peer = unix_peer(sk);
1481
1482 unix_peer(sk) = other;
1483 if (!other)
1484 WRITE_ONCE(sk->sk_state, TCP_CLOSE);
1485 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1486
1487 unix_state_double_unlock(sk, other);
1488
1489 if (other != old_peer) {
1490 unix_dgram_disconnected(sk, old_peer);
1491
1492 unix_state_lock(old_peer);
1493 if (!unix_peer(old_peer))
1494 WRITE_ONCE(old_peer->sk_state, TCP_CLOSE);
1495 unix_state_unlock(old_peer);
1496 }
1497
1498 sock_put(old_peer);
1499 } else {
1500 unix_peer(sk) = other;
1501 unix_state_double_unlock(sk, other);
1502 }
1503
1504 return 0;
1505
1506out_unlock:
1507 unix_state_double_unlock(sk, other);
1508 sock_put(other);
1509out:
1510 return err;
1511}
1512
1513static long unix_wait_for_peer(struct sock *other, long timeo)
1514 __releases(&unix_sk(other)->lock)
1515{
1516 struct unix_sock *u = unix_sk(other);
1517 int sched;
1518 DEFINE_WAIT(wait);
1519
1520 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1521
1522 sched = !sock_flag(other, SOCK_DEAD) &&
1523 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1524 unix_recvq_full_lockless(other);
1525
1526 unix_state_unlock(other);
1527
1528 if (sched)
1529 timeo = schedule_timeout(timeo);
1530
1531 finish_wait(&u->peer_wait, &wait);
1532 return timeo;
1533}
1534
1535static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1536 int addr_len, int flags)
1537{
1538 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1539 struct sock *sk = sock->sk, *newsk = NULL, *other = NULL;
1540 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1541 struct net *net = sock_net(sk);
1542 struct sk_buff *skb = NULL;
1543 unsigned char state;
1544 long timeo;
1545 int err;
1546
1547 err = unix_validate_addr(sunaddr, addr_len);
1548 if (err)
1549 goto out;
1550
1551 err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, uaddr, &addr_len);
1552 if (err)
1553 goto out;
1554
1555 if ((test_bit(SOCK_PASSCRED, &sock->flags) ||
1556 test_bit(SOCK_PASSPIDFD, &sock->flags)) &&
1557 !READ_ONCE(u->addr)) {
1558 err = unix_autobind(sk);
1559 if (err)
1560 goto out;
1561 }
1562
1563 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1564
1565 /* First of all allocate resources.
1566 If we will make it after state is locked,
1567 we will have to recheck all again in any case.
1568 */
1569
1570 /* create new sock for complete connection */
1571 newsk = unix_create1(net, NULL, 0, sock->type);
1572 if (IS_ERR(newsk)) {
1573 err = PTR_ERR(newsk);
1574 newsk = NULL;
1575 goto out;
1576 }
1577
1578 err = -ENOMEM;
1579
1580 /* Allocate skb for sending to listening sock */
1581 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1582 if (skb == NULL)
1583 goto out;
1584
1585restart:
1586 /* Find listening sock. */
1587 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type);
1588 if (IS_ERR(other)) {
1589 err = PTR_ERR(other);
1590 other = NULL;
1591 goto out;
1592 }
1593
1594 unix_state_lock(other);
1595
1596 /* Apparently VFS overslept socket death. Retry. */
1597 if (sock_flag(other, SOCK_DEAD)) {
1598 unix_state_unlock(other);
1599 sock_put(other);
1600 goto restart;
1601 }
1602
1603 err = -ECONNREFUSED;
1604 if (other->sk_state != TCP_LISTEN)
1605 goto out_unlock;
1606 if (other->sk_shutdown & RCV_SHUTDOWN)
1607 goto out_unlock;
1608
1609 if (unix_recvq_full_lockless(other)) {
1610 err = -EAGAIN;
1611 if (!timeo)
1612 goto out_unlock;
1613
1614 timeo = unix_wait_for_peer(other, timeo);
1615
1616 err = sock_intr_errno(timeo);
1617 if (signal_pending(current))
1618 goto out;
1619 sock_put(other);
1620 goto restart;
1621 }
1622
1623 /* self connect and simultaneous connect are eliminated
1624 * by rejecting TCP_LISTEN socket to avoid deadlock.
1625 */
1626 state = READ_ONCE(sk->sk_state);
1627 if (unlikely(state != TCP_CLOSE)) {
1628 err = state == TCP_ESTABLISHED ? -EISCONN : -EINVAL;
1629 goto out_unlock;
1630 }
1631
1632 unix_state_lock(sk);
1633
1634 if (unlikely(sk->sk_state != TCP_CLOSE)) {
1635 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EINVAL;
1636 unix_state_unlock(sk);
1637 goto out_unlock;
1638 }
1639
1640 err = security_unix_stream_connect(sk, other, newsk);
1641 if (err) {
1642 unix_state_unlock(sk);
1643 goto out_unlock;
1644 }
1645
1646 /* The way is open! Fastly set all the necessary fields... */
1647
1648 sock_hold(sk);
1649 unix_peer(newsk) = sk;
1650 newsk->sk_state = TCP_ESTABLISHED;
1651 newsk->sk_type = sk->sk_type;
1652 init_peercred(newsk);
1653 newu = unix_sk(newsk);
1654 newu->listener = other;
1655 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1656 otheru = unix_sk(other);
1657
1658 /* copy address information from listening to new sock
1659 *
1660 * The contents of *(otheru->addr) and otheru->path
1661 * are seen fully set up here, since we have found
1662 * otheru in hash under its lock. Insertion into the
1663 * hash chain we'd found it in had been done in an
1664 * earlier critical area protected by the chain's lock,
1665 * the same one where we'd set *(otheru->addr) contents,
1666 * as well as otheru->path and otheru->addr itself.
1667 *
1668 * Using smp_store_release() here to set newu->addr
1669 * is enough to make those stores, as well as stores
1670 * to newu->path visible to anyone who gets newu->addr
1671 * by smp_load_acquire(). IOW, the same warranties
1672 * as for unix_sock instances bound in unix_bind() or
1673 * in unix_autobind().
1674 */
1675 if (otheru->path.dentry) {
1676 path_get(&otheru->path);
1677 newu->path = otheru->path;
1678 }
1679 refcount_inc(&otheru->addr->refcnt);
1680 smp_store_release(&newu->addr, otheru->addr);
1681
1682 /* Set credentials */
1683 copy_peercred(sk, other);
1684
1685 sock->state = SS_CONNECTED;
1686 WRITE_ONCE(sk->sk_state, TCP_ESTABLISHED);
1687 sock_hold(newsk);
1688
1689 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1690 unix_peer(sk) = newsk;
1691
1692 unix_state_unlock(sk);
1693
1694 /* take ten and send info to listening sock */
1695 spin_lock(&other->sk_receive_queue.lock);
1696 __skb_queue_tail(&other->sk_receive_queue, skb);
1697 spin_unlock(&other->sk_receive_queue.lock);
1698 unix_state_unlock(other);
1699 other->sk_data_ready(other);
1700 sock_put(other);
1701 return 0;
1702
1703out_unlock:
1704 if (other)
1705 unix_state_unlock(other);
1706
1707out:
1708 kfree_skb(skb);
1709 if (newsk)
1710 unix_release_sock(newsk, 0);
1711 if (other)
1712 sock_put(other);
1713 return err;
1714}
1715
1716static int unix_socketpair(struct socket *socka, struct socket *sockb)
1717{
1718 struct sock *ska = socka->sk, *skb = sockb->sk;
1719
1720 /* Join our sockets back to back */
1721 sock_hold(ska);
1722 sock_hold(skb);
1723 unix_peer(ska) = skb;
1724 unix_peer(skb) = ska;
1725 init_peercred(ska);
1726 init_peercred(skb);
1727
1728 ska->sk_state = TCP_ESTABLISHED;
1729 skb->sk_state = TCP_ESTABLISHED;
1730 socka->state = SS_CONNECTED;
1731 sockb->state = SS_CONNECTED;
1732 return 0;
1733}
1734
1735static void unix_sock_inherit_flags(const struct socket *old,
1736 struct socket *new)
1737{
1738 if (test_bit(SOCK_PASSCRED, &old->flags))
1739 set_bit(SOCK_PASSCRED, &new->flags);
1740 if (test_bit(SOCK_PASSPIDFD, &old->flags))
1741 set_bit(SOCK_PASSPIDFD, &new->flags);
1742 if (test_bit(SOCK_PASSSEC, &old->flags))
1743 set_bit(SOCK_PASSSEC, &new->flags);
1744}
1745
1746static int unix_accept(struct socket *sock, struct socket *newsock,
1747 struct proto_accept_arg *arg)
1748{
1749 struct sock *sk = sock->sk;
1750 struct sk_buff *skb;
1751 struct sock *tsk;
1752
1753 arg->err = -EOPNOTSUPP;
1754 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1755 goto out;
1756
1757 arg->err = -EINVAL;
1758 if (READ_ONCE(sk->sk_state) != TCP_LISTEN)
1759 goto out;
1760
1761 /* If socket state is TCP_LISTEN it cannot change (for now...),
1762 * so that no locks are necessary.
1763 */
1764
1765 skb = skb_recv_datagram(sk, (arg->flags & O_NONBLOCK) ? MSG_DONTWAIT : 0,
1766 &arg->err);
1767 if (!skb) {
1768 /* This means receive shutdown. */
1769 if (arg->err == 0)
1770 arg->err = -EINVAL;
1771 goto out;
1772 }
1773
1774 tsk = skb->sk;
1775 skb_free_datagram(sk, skb);
1776 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1777
1778 /* attach accepted sock to socket */
1779 unix_state_lock(tsk);
1780 unix_update_edges(unix_sk(tsk));
1781 newsock->state = SS_CONNECTED;
1782 unix_sock_inherit_flags(sock, newsock);
1783 sock_graft(tsk, newsock);
1784 unix_state_unlock(tsk);
1785 return 0;
1786
1787out:
1788 return arg->err;
1789}
1790
1791
1792static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1793{
1794 struct sock *sk = sock->sk;
1795 struct unix_address *addr;
1796 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1797 int err = 0;
1798
1799 if (peer) {
1800 sk = unix_peer_get(sk);
1801
1802 err = -ENOTCONN;
1803 if (!sk)
1804 goto out;
1805 err = 0;
1806 } else {
1807 sock_hold(sk);
1808 }
1809
1810 addr = smp_load_acquire(&unix_sk(sk)->addr);
1811 if (!addr) {
1812 sunaddr->sun_family = AF_UNIX;
1813 sunaddr->sun_path[0] = 0;
1814 err = offsetof(struct sockaddr_un, sun_path);
1815 } else {
1816 err = addr->len;
1817 memcpy(sunaddr, addr->name, addr->len);
1818
1819 if (peer)
1820 BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err,
1821 CGROUP_UNIX_GETPEERNAME);
1822 else
1823 BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err,
1824 CGROUP_UNIX_GETSOCKNAME);
1825 }
1826 sock_put(sk);
1827out:
1828 return err;
1829}
1830
1831/* The "user->unix_inflight" variable is protected by the garbage
1832 * collection lock, and we just read it locklessly here. If you go
1833 * over the limit, there might be a tiny race in actually noticing
1834 * it across threads. Tough.
1835 */
1836static inline bool too_many_unix_fds(struct task_struct *p)
1837{
1838 struct user_struct *user = current_user();
1839
1840 if (unlikely(READ_ONCE(user->unix_inflight) > task_rlimit(p, RLIMIT_NOFILE)))
1841 return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1842 return false;
1843}
1844
1845static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1846{
1847 if (too_many_unix_fds(current))
1848 return -ETOOMANYREFS;
1849
1850 UNIXCB(skb).fp = scm->fp;
1851 scm->fp = NULL;
1852
1853 if (unix_prepare_fpl(UNIXCB(skb).fp))
1854 return -ENOMEM;
1855
1856 return 0;
1857}
1858
1859static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1860{
1861 scm->fp = UNIXCB(skb).fp;
1862 UNIXCB(skb).fp = NULL;
1863
1864 unix_destroy_fpl(scm->fp);
1865}
1866
1867static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb)
1868{
1869 scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1870}
1871
1872static void unix_destruct_scm(struct sk_buff *skb)
1873{
1874 struct scm_cookie scm;
1875
1876 memset(&scm, 0, sizeof(scm));
1877 scm.pid = UNIXCB(skb).pid;
1878 if (UNIXCB(skb).fp)
1879 unix_detach_fds(&scm, skb);
1880
1881 /* Alas, it calls VFS */
1882 /* So fscking what? fput() had been SMP-safe since the last Summer */
1883 scm_destroy(&scm);
1884 sock_wfree(skb);
1885}
1886
1887static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1888{
1889 int err = 0;
1890
1891 UNIXCB(skb).pid = get_pid(scm->pid);
1892 UNIXCB(skb).uid = scm->creds.uid;
1893 UNIXCB(skb).gid = scm->creds.gid;
1894 UNIXCB(skb).fp = NULL;
1895 unix_get_secdata(scm, skb);
1896 if (scm->fp && send_fds)
1897 err = unix_attach_fds(scm, skb);
1898
1899 skb->destructor = unix_destruct_scm;
1900 return err;
1901}
1902
1903static bool unix_passcred_enabled(const struct socket *sock,
1904 const struct sock *other)
1905{
1906 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1907 test_bit(SOCK_PASSPIDFD, &sock->flags) ||
1908 !other->sk_socket ||
1909 test_bit(SOCK_PASSCRED, &other->sk_socket->flags) ||
1910 test_bit(SOCK_PASSPIDFD, &other->sk_socket->flags);
1911}
1912
1913/*
1914 * Some apps rely on write() giving SCM_CREDENTIALS
1915 * We include credentials if source or destination socket
1916 * asserted SOCK_PASSCRED.
1917 */
1918static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1919 const struct sock *other)
1920{
1921 if (UNIXCB(skb).pid)
1922 return;
1923 if (unix_passcred_enabled(sock, other)) {
1924 UNIXCB(skb).pid = get_pid(task_tgid(current));
1925 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1926 }
1927}
1928
1929static bool unix_skb_scm_eq(struct sk_buff *skb,
1930 struct scm_cookie *scm)
1931{
1932 return UNIXCB(skb).pid == scm->pid &&
1933 uid_eq(UNIXCB(skb).uid, scm->creds.uid) &&
1934 gid_eq(UNIXCB(skb).gid, scm->creds.gid) &&
1935 unix_secdata_eq(scm, skb);
1936}
1937
1938static void scm_stat_add(struct sock *sk, struct sk_buff *skb)
1939{
1940 struct scm_fp_list *fp = UNIXCB(skb).fp;
1941 struct unix_sock *u = unix_sk(sk);
1942
1943 if (unlikely(fp && fp->count)) {
1944 atomic_add(fp->count, &u->scm_stat.nr_fds);
1945 unix_add_edges(fp, u);
1946 }
1947}
1948
1949static void scm_stat_del(struct sock *sk, struct sk_buff *skb)
1950{
1951 struct scm_fp_list *fp = UNIXCB(skb).fp;
1952 struct unix_sock *u = unix_sk(sk);
1953
1954 if (unlikely(fp && fp->count)) {
1955 atomic_sub(fp->count, &u->scm_stat.nr_fds);
1956 unix_del_edges(fp);
1957 }
1958}
1959
1960/*
1961 * Send AF_UNIX data.
1962 */
1963
1964static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1965 size_t len)
1966{
1967 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1968 struct sock *sk = sock->sk, *other = NULL;
1969 struct unix_sock *u = unix_sk(sk);
1970 struct scm_cookie scm;
1971 struct sk_buff *skb;
1972 int data_len = 0;
1973 int sk_locked;
1974 long timeo;
1975 int err;
1976
1977 err = scm_send(sock, msg, &scm, false);
1978 if (err < 0)
1979 return err;
1980
1981 wait_for_unix_gc(scm.fp);
1982
1983 err = -EOPNOTSUPP;
1984 if (msg->msg_flags&MSG_OOB)
1985 goto out;
1986
1987 if (msg->msg_namelen) {
1988 err = unix_validate_addr(sunaddr, msg->msg_namelen);
1989 if (err)
1990 goto out;
1991
1992 err = BPF_CGROUP_RUN_PROG_UNIX_SENDMSG_LOCK(sk,
1993 msg->msg_name,
1994 &msg->msg_namelen,
1995 NULL);
1996 if (err)
1997 goto out;
1998 } else {
1999 sunaddr = NULL;
2000 err = -ENOTCONN;
2001 other = unix_peer_get(sk);
2002 if (!other)
2003 goto out;
2004 }
2005
2006 if ((test_bit(SOCK_PASSCRED, &sock->flags) ||
2007 test_bit(SOCK_PASSPIDFD, &sock->flags)) &&
2008 !READ_ONCE(u->addr)) {
2009 err = unix_autobind(sk);
2010 if (err)
2011 goto out;
2012 }
2013
2014 err = -EMSGSIZE;
2015 if (len > READ_ONCE(sk->sk_sndbuf) - 32)
2016 goto out;
2017
2018 if (len > SKB_MAX_ALLOC) {
2019 data_len = min_t(size_t,
2020 len - SKB_MAX_ALLOC,
2021 MAX_SKB_FRAGS * PAGE_SIZE);
2022 data_len = PAGE_ALIGN(data_len);
2023
2024 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
2025 }
2026
2027 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
2028 msg->msg_flags & MSG_DONTWAIT, &err,
2029 PAGE_ALLOC_COSTLY_ORDER);
2030 if (skb == NULL)
2031 goto out;
2032
2033 err = unix_scm_to_skb(&scm, skb, true);
2034 if (err < 0)
2035 goto out_free;
2036
2037 skb_put(skb, len - data_len);
2038 skb->data_len = data_len;
2039 skb->len = len;
2040 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
2041 if (err)
2042 goto out_free;
2043
2044 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
2045
2046restart:
2047 if (!other) {
2048 err = -ECONNRESET;
2049 if (sunaddr == NULL)
2050 goto out_free;
2051
2052 other = unix_find_other(sock_net(sk), sunaddr, msg->msg_namelen,
2053 sk->sk_type);
2054 if (IS_ERR(other)) {
2055 err = PTR_ERR(other);
2056 other = NULL;
2057 goto out_free;
2058 }
2059 }
2060
2061 if (sk_filter(other, skb) < 0) {
2062 /* Toss the packet but do not return any error to the sender */
2063 err = len;
2064 goto out_free;
2065 }
2066
2067 sk_locked = 0;
2068 unix_state_lock(other);
2069restart_locked:
2070 err = -EPERM;
2071 if (!unix_may_send(sk, other))
2072 goto out_unlock;
2073
2074 if (unlikely(sock_flag(other, SOCK_DEAD))) {
2075 /*
2076 * Check with 1003.1g - what should
2077 * datagram error
2078 */
2079 unix_state_unlock(other);
2080 sock_put(other);
2081
2082 if (!sk_locked)
2083 unix_state_lock(sk);
2084
2085 err = 0;
2086 if (sk->sk_type == SOCK_SEQPACKET) {
2087 /* We are here only when racing with unix_release_sock()
2088 * is clearing @other. Never change state to TCP_CLOSE
2089 * unlike SOCK_DGRAM wants.
2090 */
2091 unix_state_unlock(sk);
2092 err = -EPIPE;
2093 } else if (unix_peer(sk) == other) {
2094 unix_peer(sk) = NULL;
2095 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
2096
2097 WRITE_ONCE(sk->sk_state, TCP_CLOSE);
2098 unix_state_unlock(sk);
2099
2100 unix_dgram_disconnected(sk, other);
2101 sock_put(other);
2102 err = -ECONNREFUSED;
2103 } else {
2104 unix_state_unlock(sk);
2105 }
2106
2107 other = NULL;
2108 if (err)
2109 goto out_free;
2110 goto restart;
2111 }
2112
2113 err = -EPIPE;
2114 if (other->sk_shutdown & RCV_SHUTDOWN)
2115 goto out_unlock;
2116
2117 if (sk->sk_type != SOCK_SEQPACKET) {
2118 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
2119 if (err)
2120 goto out_unlock;
2121 }
2122
2123 /* other == sk && unix_peer(other) != sk if
2124 * - unix_peer(sk) == NULL, destination address bound to sk
2125 * - unix_peer(sk) == sk by time of get but disconnected before lock
2126 */
2127 if (other != sk &&
2128 unlikely(unix_peer(other) != sk &&
2129 unix_recvq_full_lockless(other))) {
2130 if (timeo) {
2131 timeo = unix_wait_for_peer(other, timeo);
2132
2133 err = sock_intr_errno(timeo);
2134 if (signal_pending(current))
2135 goto out_free;
2136
2137 goto restart;
2138 }
2139
2140 if (!sk_locked) {
2141 unix_state_unlock(other);
2142 unix_state_double_lock(sk, other);
2143 }
2144
2145 if (unix_peer(sk) != other ||
2146 unix_dgram_peer_wake_me(sk, other)) {
2147 err = -EAGAIN;
2148 sk_locked = 1;
2149 goto out_unlock;
2150 }
2151
2152 if (!sk_locked) {
2153 sk_locked = 1;
2154 goto restart_locked;
2155 }
2156 }
2157
2158 if (unlikely(sk_locked))
2159 unix_state_unlock(sk);
2160
2161 if (sock_flag(other, SOCK_RCVTSTAMP))
2162 __net_timestamp(skb);
2163 maybe_add_creds(skb, sock, other);
2164 scm_stat_add(other, skb);
2165 skb_queue_tail(&other->sk_receive_queue, skb);
2166 unix_state_unlock(other);
2167 other->sk_data_ready(other);
2168 sock_put(other);
2169 scm_destroy(&scm);
2170 return len;
2171
2172out_unlock:
2173 if (sk_locked)
2174 unix_state_unlock(sk);
2175 unix_state_unlock(other);
2176out_free:
2177 kfree_skb(skb);
2178out:
2179 if (other)
2180 sock_put(other);
2181 scm_destroy(&scm);
2182 return err;
2183}
2184
2185/* We use paged skbs for stream sockets, and limit occupancy to 32768
2186 * bytes, and a minimum of a full page.
2187 */
2188#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
2189
2190#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2191static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other,
2192 struct scm_cookie *scm, bool fds_sent)
2193{
2194 struct unix_sock *ousk = unix_sk(other);
2195 struct sk_buff *skb;
2196 int err = 0;
2197
2198 skb = sock_alloc_send_skb(sock->sk, 1, msg->msg_flags & MSG_DONTWAIT, &err);
2199
2200 if (!skb)
2201 return err;
2202
2203 err = unix_scm_to_skb(scm, skb, !fds_sent);
2204 if (err < 0) {
2205 kfree_skb(skb);
2206 return err;
2207 }
2208 skb_put(skb, 1);
2209 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, 1);
2210
2211 if (err) {
2212 kfree_skb(skb);
2213 return err;
2214 }
2215
2216 unix_state_lock(other);
2217
2218 if (sock_flag(other, SOCK_DEAD) ||
2219 (other->sk_shutdown & RCV_SHUTDOWN)) {
2220 unix_state_unlock(other);
2221 kfree_skb(skb);
2222 return -EPIPE;
2223 }
2224
2225 maybe_add_creds(skb, sock, other);
2226 scm_stat_add(other, skb);
2227
2228 spin_lock(&other->sk_receive_queue.lock);
2229 WRITE_ONCE(ousk->oob_skb, skb);
2230 __skb_queue_tail(&other->sk_receive_queue, skb);
2231 spin_unlock(&other->sk_receive_queue.lock);
2232
2233 sk_send_sigurg(other);
2234 unix_state_unlock(other);
2235 other->sk_data_ready(other);
2236
2237 return err;
2238}
2239#endif
2240
2241static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
2242 size_t len)
2243{
2244 struct sock *sk = sock->sk;
2245 struct sock *other = NULL;
2246 int err, size;
2247 struct sk_buff *skb;
2248 int sent = 0;
2249 struct scm_cookie scm;
2250 bool fds_sent = false;
2251 int data_len;
2252
2253 err = scm_send(sock, msg, &scm, false);
2254 if (err < 0)
2255 return err;
2256
2257 wait_for_unix_gc(scm.fp);
2258
2259 err = -EOPNOTSUPP;
2260 if (msg->msg_flags & MSG_OOB) {
2261#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2262 if (len)
2263 len--;
2264 else
2265#endif
2266 goto out_err;
2267 }
2268
2269 if (msg->msg_namelen) {
2270 err = READ_ONCE(sk->sk_state) == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
2271 goto out_err;
2272 } else {
2273 err = -ENOTCONN;
2274 other = unix_peer(sk);
2275 if (!other)
2276 goto out_err;
2277 }
2278
2279 if (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN)
2280 goto pipe_err;
2281
2282 while (sent < len) {
2283 size = len - sent;
2284
2285 if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {
2286 skb = sock_alloc_send_pskb(sk, 0, 0,
2287 msg->msg_flags & MSG_DONTWAIT,
2288 &err, 0);
2289 } else {
2290 /* Keep two messages in the pipe so it schedules better */
2291 size = min_t(int, size, (READ_ONCE(sk->sk_sndbuf) >> 1) - 64);
2292
2293 /* allow fallback to order-0 allocations */
2294 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
2295
2296 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
2297
2298 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
2299
2300 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
2301 msg->msg_flags & MSG_DONTWAIT, &err,
2302 get_order(UNIX_SKB_FRAGS_SZ));
2303 }
2304 if (!skb)
2305 goto out_err;
2306
2307 /* Only send the fds in the first buffer */
2308 err = unix_scm_to_skb(&scm, skb, !fds_sent);
2309 if (err < 0) {
2310 kfree_skb(skb);
2311 goto out_err;
2312 }
2313 fds_sent = true;
2314
2315 if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {
2316 skb->ip_summed = CHECKSUM_UNNECESSARY;
2317 err = skb_splice_from_iter(skb, &msg->msg_iter, size,
2318 sk->sk_allocation);
2319 if (err < 0) {
2320 kfree_skb(skb);
2321 goto out_err;
2322 }
2323 size = err;
2324 refcount_add(size, &sk->sk_wmem_alloc);
2325 } else {
2326 skb_put(skb, size - data_len);
2327 skb->data_len = data_len;
2328 skb->len = size;
2329 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
2330 if (err) {
2331 kfree_skb(skb);
2332 goto out_err;
2333 }
2334 }
2335
2336 unix_state_lock(other);
2337
2338 if (sock_flag(other, SOCK_DEAD) ||
2339 (other->sk_shutdown & RCV_SHUTDOWN))
2340 goto pipe_err_free;
2341
2342 maybe_add_creds(skb, sock, other);
2343 scm_stat_add(other, skb);
2344 skb_queue_tail(&other->sk_receive_queue, skb);
2345 unix_state_unlock(other);
2346 other->sk_data_ready(other);
2347 sent += size;
2348 }
2349
2350#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2351 if (msg->msg_flags & MSG_OOB) {
2352 err = queue_oob(sock, msg, other, &scm, fds_sent);
2353 if (err)
2354 goto out_err;
2355 sent++;
2356 }
2357#endif
2358
2359 scm_destroy(&scm);
2360
2361 return sent;
2362
2363pipe_err_free:
2364 unix_state_unlock(other);
2365 kfree_skb(skb);
2366pipe_err:
2367 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
2368 send_sig(SIGPIPE, current, 0);
2369 err = -EPIPE;
2370out_err:
2371 scm_destroy(&scm);
2372 return sent ? : err;
2373}
2374
2375static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2376 size_t len)
2377{
2378 int err;
2379 struct sock *sk = sock->sk;
2380
2381 err = sock_error(sk);
2382 if (err)
2383 return err;
2384
2385 if (READ_ONCE(sk->sk_state) != TCP_ESTABLISHED)
2386 return -ENOTCONN;
2387
2388 if (msg->msg_namelen)
2389 msg->msg_namelen = 0;
2390
2391 return unix_dgram_sendmsg(sock, msg, len);
2392}
2393
2394static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2395 size_t size, int flags)
2396{
2397 struct sock *sk = sock->sk;
2398
2399 if (READ_ONCE(sk->sk_state) != TCP_ESTABLISHED)
2400 return -ENOTCONN;
2401
2402 return unix_dgram_recvmsg(sock, msg, size, flags);
2403}
2404
2405static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2406{
2407 struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
2408
2409 if (addr) {
2410 msg->msg_namelen = addr->len;
2411 memcpy(msg->msg_name, addr->name, addr->len);
2412 }
2413}
2414
2415int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size,
2416 int flags)
2417{
2418 struct scm_cookie scm;
2419 struct socket *sock = sk->sk_socket;
2420 struct unix_sock *u = unix_sk(sk);
2421 struct sk_buff *skb, *last;
2422 long timeo;
2423 int skip;
2424 int err;
2425
2426 err = -EOPNOTSUPP;
2427 if (flags&MSG_OOB)
2428 goto out;
2429
2430 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2431
2432 do {
2433 mutex_lock(&u->iolock);
2434
2435 skip = sk_peek_offset(sk, flags);
2436 skb = __skb_try_recv_datagram(sk, &sk->sk_receive_queue, flags,
2437 &skip, &err, &last);
2438 if (skb) {
2439 if (!(flags & MSG_PEEK))
2440 scm_stat_del(sk, skb);
2441 break;
2442 }
2443
2444 mutex_unlock(&u->iolock);
2445
2446 if (err != -EAGAIN)
2447 break;
2448 } while (timeo &&
2449 !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue,
2450 &err, &timeo, last));
2451
2452 if (!skb) { /* implies iolock unlocked */
2453 unix_state_lock(sk);
2454 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2455 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2456 (sk->sk_shutdown & RCV_SHUTDOWN))
2457 err = 0;
2458 unix_state_unlock(sk);
2459 goto out;
2460 }
2461
2462 if (wq_has_sleeper(&u->peer_wait))
2463 wake_up_interruptible_sync_poll(&u->peer_wait,
2464 EPOLLOUT | EPOLLWRNORM |
2465 EPOLLWRBAND);
2466
2467 if (msg->msg_name) {
2468 unix_copy_addr(msg, skb->sk);
2469
2470 BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk,
2471 msg->msg_name,
2472 &msg->msg_namelen);
2473 }
2474
2475 if (size > skb->len - skip)
2476 size = skb->len - skip;
2477 else if (size < skb->len - skip)
2478 msg->msg_flags |= MSG_TRUNC;
2479
2480 err = skb_copy_datagram_msg(skb, skip, msg, size);
2481 if (err)
2482 goto out_free;
2483
2484 if (sock_flag(sk, SOCK_RCVTSTAMP))
2485 __sock_recv_timestamp(msg, sk, skb);
2486
2487 memset(&scm, 0, sizeof(scm));
2488
2489 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2490 unix_set_secdata(&scm, skb);
2491
2492 if (!(flags & MSG_PEEK)) {
2493 if (UNIXCB(skb).fp)
2494 unix_detach_fds(&scm, skb);
2495
2496 sk_peek_offset_bwd(sk, skb->len);
2497 } else {
2498 /* It is questionable: on PEEK we could:
2499 - do not return fds - good, but too simple 8)
2500 - return fds, and do not return them on read (old strategy,
2501 apparently wrong)
2502 - clone fds (I chose it for now, it is the most universal
2503 solution)
2504
2505 POSIX 1003.1g does not actually define this clearly
2506 at all. POSIX 1003.1g doesn't define a lot of things
2507 clearly however!
2508
2509 */
2510
2511 sk_peek_offset_fwd(sk, size);
2512
2513 if (UNIXCB(skb).fp)
2514 unix_peek_fds(&scm, skb);
2515 }
2516 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2517
2518 scm_recv_unix(sock, msg, &scm, flags);
2519
2520out_free:
2521 skb_free_datagram(sk, skb);
2522 mutex_unlock(&u->iolock);
2523out:
2524 return err;
2525}
2526
2527static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
2528 int flags)
2529{
2530 struct sock *sk = sock->sk;
2531
2532#ifdef CONFIG_BPF_SYSCALL
2533 const struct proto *prot = READ_ONCE(sk->sk_prot);
2534
2535 if (prot != &unix_dgram_proto)
2536 return prot->recvmsg(sk, msg, size, flags, NULL);
2537#endif
2538 return __unix_dgram_recvmsg(sk, msg, size, flags);
2539}
2540
2541static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
2542{
2543 struct unix_sock *u = unix_sk(sk);
2544 struct sk_buff *skb;
2545 int err;
2546
2547 mutex_lock(&u->iolock);
2548 skb = skb_recv_datagram(sk, MSG_DONTWAIT, &err);
2549 mutex_unlock(&u->iolock);
2550 if (!skb)
2551 return err;
2552
2553 return recv_actor(sk, skb);
2554}
2555
2556/*
2557 * Sleep until more data has arrived. But check for races..
2558 */
2559static long unix_stream_data_wait(struct sock *sk, long timeo,
2560 struct sk_buff *last, unsigned int last_len,
2561 bool freezable)
2562{
2563 unsigned int state = TASK_INTERRUPTIBLE | freezable * TASK_FREEZABLE;
2564 struct sk_buff *tail;
2565 DEFINE_WAIT(wait);
2566
2567 unix_state_lock(sk);
2568
2569 for (;;) {
2570 prepare_to_wait(sk_sleep(sk), &wait, state);
2571
2572 tail = skb_peek_tail(&sk->sk_receive_queue);
2573 if (tail != last ||
2574 (tail && tail->len != last_len) ||
2575 sk->sk_err ||
2576 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2577 signal_pending(current) ||
2578 !timeo)
2579 break;
2580
2581 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2582 unix_state_unlock(sk);
2583 timeo = schedule_timeout(timeo);
2584 unix_state_lock(sk);
2585
2586 if (sock_flag(sk, SOCK_DEAD))
2587 break;
2588
2589 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2590 }
2591
2592 finish_wait(sk_sleep(sk), &wait);
2593 unix_state_unlock(sk);
2594 return timeo;
2595}
2596
2597static unsigned int unix_skb_len(const struct sk_buff *skb)
2598{
2599 return skb->len - UNIXCB(skb).consumed;
2600}
2601
2602struct unix_stream_read_state {
2603 int (*recv_actor)(struct sk_buff *, int, int,
2604 struct unix_stream_read_state *);
2605 struct socket *socket;
2606 struct msghdr *msg;
2607 struct pipe_inode_info *pipe;
2608 size_t size;
2609 int flags;
2610 unsigned int splice_flags;
2611};
2612
2613#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2614static int unix_stream_recv_urg(struct unix_stream_read_state *state)
2615{
2616 struct socket *sock = state->socket;
2617 struct sock *sk = sock->sk;
2618 struct unix_sock *u = unix_sk(sk);
2619 int chunk = 1;
2620 struct sk_buff *oob_skb;
2621
2622 mutex_lock(&u->iolock);
2623 unix_state_lock(sk);
2624 spin_lock(&sk->sk_receive_queue.lock);
2625
2626 if (sock_flag(sk, SOCK_URGINLINE) || !u->oob_skb) {
2627 spin_unlock(&sk->sk_receive_queue.lock);
2628 unix_state_unlock(sk);
2629 mutex_unlock(&u->iolock);
2630 return -EINVAL;
2631 }
2632
2633 oob_skb = u->oob_skb;
2634
2635 if (!(state->flags & MSG_PEEK))
2636 WRITE_ONCE(u->oob_skb, NULL);
2637
2638 spin_unlock(&sk->sk_receive_queue.lock);
2639 unix_state_unlock(sk);
2640
2641 chunk = state->recv_actor(oob_skb, 0, chunk, state);
2642
2643 if (!(state->flags & MSG_PEEK))
2644 UNIXCB(oob_skb).consumed += 1;
2645
2646 mutex_unlock(&u->iolock);
2647
2648 if (chunk < 0)
2649 return -EFAULT;
2650
2651 state->msg->msg_flags |= MSG_OOB;
2652 return 1;
2653}
2654
2655static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
2656 int flags, int copied)
2657{
2658 struct sk_buff *read_skb = NULL, *unread_skb = NULL;
2659 struct unix_sock *u = unix_sk(sk);
2660
2661 if (likely(unix_skb_len(skb) && skb != READ_ONCE(u->oob_skb)))
2662 return skb;
2663
2664 spin_lock(&sk->sk_receive_queue.lock);
2665
2666 if (!unix_skb_len(skb)) {
2667 if (copied && (!u->oob_skb || skb == u->oob_skb)) {
2668 skb = NULL;
2669 } else if (flags & MSG_PEEK) {
2670 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2671 } else {
2672 read_skb = skb;
2673 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2674 __skb_unlink(read_skb, &sk->sk_receive_queue);
2675 }
2676
2677 if (!skb)
2678 goto unlock;
2679 }
2680
2681 if (skb != u->oob_skb)
2682 goto unlock;
2683
2684 if (copied) {
2685 skb = NULL;
2686 } else if (!(flags & MSG_PEEK)) {
2687 WRITE_ONCE(u->oob_skb, NULL);
2688
2689 if (!sock_flag(sk, SOCK_URGINLINE)) {
2690 __skb_unlink(skb, &sk->sk_receive_queue);
2691 unread_skb = skb;
2692 skb = skb_peek(&sk->sk_receive_queue);
2693 }
2694 } else if (!sock_flag(sk, SOCK_URGINLINE)) {
2695 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2696 }
2697
2698unlock:
2699 spin_unlock(&sk->sk_receive_queue.lock);
2700
2701 consume_skb(read_skb);
2702 kfree_skb(unread_skb);
2703
2704 return skb;
2705}
2706#endif
2707
2708static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
2709{
2710 struct unix_sock *u = unix_sk(sk);
2711 struct sk_buff *skb;
2712 int err;
2713
2714 if (unlikely(READ_ONCE(sk->sk_state) != TCP_ESTABLISHED))
2715 return -ENOTCONN;
2716
2717 mutex_lock(&u->iolock);
2718 skb = skb_recv_datagram(sk, MSG_DONTWAIT, &err);
2719 mutex_unlock(&u->iolock);
2720 if (!skb)
2721 return err;
2722
2723#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2724 if (unlikely(skb == READ_ONCE(u->oob_skb))) {
2725 bool drop = false;
2726
2727 unix_state_lock(sk);
2728
2729 if (sock_flag(sk, SOCK_DEAD)) {
2730 unix_state_unlock(sk);
2731 kfree_skb(skb);
2732 return -ECONNRESET;
2733 }
2734
2735 spin_lock(&sk->sk_receive_queue.lock);
2736 if (likely(skb == u->oob_skb)) {
2737 WRITE_ONCE(u->oob_skb, NULL);
2738 drop = true;
2739 }
2740 spin_unlock(&sk->sk_receive_queue.lock);
2741
2742 unix_state_unlock(sk);
2743
2744 if (drop) {
2745 kfree_skb(skb);
2746 return -EAGAIN;
2747 }
2748 }
2749#endif
2750
2751 return recv_actor(sk, skb);
2752}
2753
2754static int unix_stream_read_generic(struct unix_stream_read_state *state,
2755 bool freezable)
2756{
2757 struct scm_cookie scm;
2758 struct socket *sock = state->socket;
2759 struct sock *sk = sock->sk;
2760 struct unix_sock *u = unix_sk(sk);
2761 int copied = 0;
2762 int flags = state->flags;
2763 int noblock = flags & MSG_DONTWAIT;
2764 bool check_creds = false;
2765 int target;
2766 int err = 0;
2767 long timeo;
2768 int skip;
2769 size_t size = state->size;
2770 unsigned int last_len;
2771
2772 if (unlikely(READ_ONCE(sk->sk_state) != TCP_ESTABLISHED)) {
2773 err = -EINVAL;
2774 goto out;
2775 }
2776
2777 if (unlikely(flags & MSG_OOB)) {
2778 err = -EOPNOTSUPP;
2779#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2780 err = unix_stream_recv_urg(state);
2781#endif
2782 goto out;
2783 }
2784
2785 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2786 timeo = sock_rcvtimeo(sk, noblock);
2787
2788 memset(&scm, 0, sizeof(scm));
2789
2790 /* Lock the socket to prevent queue disordering
2791 * while sleeps in memcpy_tomsg
2792 */
2793 mutex_lock(&u->iolock);
2794
2795 skip = max(sk_peek_offset(sk, flags), 0);
2796
2797 do {
2798 struct sk_buff *skb, *last;
2799 int chunk;
2800
2801redo:
2802 unix_state_lock(sk);
2803 if (sock_flag(sk, SOCK_DEAD)) {
2804 err = -ECONNRESET;
2805 goto unlock;
2806 }
2807 last = skb = skb_peek(&sk->sk_receive_queue);
2808 last_len = last ? last->len : 0;
2809
2810again:
2811#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2812 if (skb) {
2813 skb = manage_oob(skb, sk, flags, copied);
2814 if (!skb && copied) {
2815 unix_state_unlock(sk);
2816 break;
2817 }
2818 }
2819#endif
2820 if (skb == NULL) {
2821 if (copied >= target)
2822 goto unlock;
2823
2824 /*
2825 * POSIX 1003.1g mandates this order.
2826 */
2827
2828 err = sock_error(sk);
2829 if (err)
2830 goto unlock;
2831 if (sk->sk_shutdown & RCV_SHUTDOWN)
2832 goto unlock;
2833
2834 unix_state_unlock(sk);
2835 if (!timeo) {
2836 err = -EAGAIN;
2837 break;
2838 }
2839
2840 mutex_unlock(&u->iolock);
2841
2842 timeo = unix_stream_data_wait(sk, timeo, last,
2843 last_len, freezable);
2844
2845 if (signal_pending(current)) {
2846 err = sock_intr_errno(timeo);
2847 scm_destroy(&scm);
2848 goto out;
2849 }
2850
2851 mutex_lock(&u->iolock);
2852 goto redo;
2853unlock:
2854 unix_state_unlock(sk);
2855 break;
2856 }
2857
2858 while (skip >= unix_skb_len(skb)) {
2859 skip -= unix_skb_len(skb);
2860 last = skb;
2861 last_len = skb->len;
2862 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2863 if (!skb)
2864 goto again;
2865 }
2866
2867 unix_state_unlock(sk);
2868
2869 if (check_creds) {
2870 /* Never glue messages from different writers */
2871 if (!unix_skb_scm_eq(skb, &scm))
2872 break;
2873 } else if (test_bit(SOCK_PASSCRED, &sock->flags) ||
2874 test_bit(SOCK_PASSPIDFD, &sock->flags)) {
2875 /* Copy credentials */
2876 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2877 unix_set_secdata(&scm, skb);
2878 check_creds = true;
2879 }
2880
2881 /* Copy address just once */
2882 if (state->msg && state->msg->msg_name) {
2883 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2884 state->msg->msg_name);
2885 unix_copy_addr(state->msg, skb->sk);
2886
2887 BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk,
2888 state->msg->msg_name,
2889 &state->msg->msg_namelen);
2890
2891 sunaddr = NULL;
2892 }
2893
2894 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2895 chunk = state->recv_actor(skb, skip, chunk, state);
2896 if (chunk < 0) {
2897 if (copied == 0)
2898 copied = -EFAULT;
2899 break;
2900 }
2901 copied += chunk;
2902 size -= chunk;
2903
2904 /* Mark read part of skb as used */
2905 if (!(flags & MSG_PEEK)) {
2906 UNIXCB(skb).consumed += chunk;
2907
2908 sk_peek_offset_bwd(sk, chunk);
2909
2910 if (UNIXCB(skb).fp) {
2911 scm_stat_del(sk, skb);
2912 unix_detach_fds(&scm, skb);
2913 }
2914
2915 if (unix_skb_len(skb))
2916 break;
2917
2918 skb_unlink(skb, &sk->sk_receive_queue);
2919 consume_skb(skb);
2920
2921 if (scm.fp)
2922 break;
2923 } else {
2924 /* It is questionable, see note in unix_dgram_recvmsg.
2925 */
2926 if (UNIXCB(skb).fp)
2927 unix_peek_fds(&scm, skb);
2928
2929 sk_peek_offset_fwd(sk, chunk);
2930
2931 if (UNIXCB(skb).fp)
2932 break;
2933
2934 skip = 0;
2935 last = skb;
2936 last_len = skb->len;
2937 unix_state_lock(sk);
2938 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2939 if (skb)
2940 goto again;
2941 unix_state_unlock(sk);
2942 break;
2943 }
2944 } while (size);
2945
2946 mutex_unlock(&u->iolock);
2947 if (state->msg)
2948 scm_recv_unix(sock, state->msg, &scm, flags);
2949 else
2950 scm_destroy(&scm);
2951out:
2952 return copied ? : err;
2953}
2954
2955static int unix_stream_read_actor(struct sk_buff *skb,
2956 int skip, int chunk,
2957 struct unix_stream_read_state *state)
2958{
2959 int ret;
2960
2961 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2962 state->msg, chunk);
2963 return ret ?: chunk;
2964}
2965
2966int __unix_stream_recvmsg(struct sock *sk, struct msghdr *msg,
2967 size_t size, int flags)
2968{
2969 struct unix_stream_read_state state = {
2970 .recv_actor = unix_stream_read_actor,
2971 .socket = sk->sk_socket,
2972 .msg = msg,
2973 .size = size,
2974 .flags = flags
2975 };
2976
2977 return unix_stream_read_generic(&state, true);
2978}
2979
2980static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2981 size_t size, int flags)
2982{
2983 struct unix_stream_read_state state = {
2984 .recv_actor = unix_stream_read_actor,
2985 .socket = sock,
2986 .msg = msg,
2987 .size = size,
2988 .flags = flags
2989 };
2990
2991#ifdef CONFIG_BPF_SYSCALL
2992 struct sock *sk = sock->sk;
2993 const struct proto *prot = READ_ONCE(sk->sk_prot);
2994
2995 if (prot != &unix_stream_proto)
2996 return prot->recvmsg(sk, msg, size, flags, NULL);
2997#endif
2998 return unix_stream_read_generic(&state, true);
2999}
3000
3001static int unix_stream_splice_actor(struct sk_buff *skb,
3002 int skip, int chunk,
3003 struct unix_stream_read_state *state)
3004{
3005 return skb_splice_bits(skb, state->socket->sk,
3006 UNIXCB(skb).consumed + skip,
3007 state->pipe, chunk, state->splice_flags);
3008}
3009
3010static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
3011 struct pipe_inode_info *pipe,
3012 size_t size, unsigned int flags)
3013{
3014 struct unix_stream_read_state state = {
3015 .recv_actor = unix_stream_splice_actor,
3016 .socket = sock,
3017 .pipe = pipe,
3018 .size = size,
3019 .splice_flags = flags,
3020 };
3021
3022 if (unlikely(*ppos))
3023 return -ESPIPE;
3024
3025 if (sock->file->f_flags & O_NONBLOCK ||
3026 flags & SPLICE_F_NONBLOCK)
3027 state.flags = MSG_DONTWAIT;
3028
3029 return unix_stream_read_generic(&state, false);
3030}
3031
3032static int unix_shutdown(struct socket *sock, int mode)
3033{
3034 struct sock *sk = sock->sk;
3035 struct sock *other;
3036
3037 if (mode < SHUT_RD || mode > SHUT_RDWR)
3038 return -EINVAL;
3039 /* This maps:
3040 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
3041 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
3042 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
3043 */
3044 ++mode;
3045
3046 unix_state_lock(sk);
3047 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | mode);
3048 other = unix_peer(sk);
3049 if (other)
3050 sock_hold(other);
3051 unix_state_unlock(sk);
3052 sk->sk_state_change(sk);
3053
3054 if (other &&
3055 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
3056
3057 int peer_mode = 0;
3058 const struct proto *prot = READ_ONCE(other->sk_prot);
3059
3060 if (prot->unhash)
3061 prot->unhash(other);
3062 if (mode&RCV_SHUTDOWN)
3063 peer_mode |= SEND_SHUTDOWN;
3064 if (mode&SEND_SHUTDOWN)
3065 peer_mode |= RCV_SHUTDOWN;
3066 unix_state_lock(other);
3067 WRITE_ONCE(other->sk_shutdown, other->sk_shutdown | peer_mode);
3068 unix_state_unlock(other);
3069 other->sk_state_change(other);
3070 if (peer_mode == SHUTDOWN_MASK)
3071 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
3072 else if (peer_mode & RCV_SHUTDOWN)
3073 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
3074 }
3075 if (other)
3076 sock_put(other);
3077
3078 return 0;
3079}
3080
3081long unix_inq_len(struct sock *sk)
3082{
3083 struct sk_buff *skb;
3084 long amount = 0;
3085
3086 if (READ_ONCE(sk->sk_state) == TCP_LISTEN)
3087 return -EINVAL;
3088
3089 spin_lock(&sk->sk_receive_queue.lock);
3090 if (sk->sk_type == SOCK_STREAM ||
3091 sk->sk_type == SOCK_SEQPACKET) {
3092 skb_queue_walk(&sk->sk_receive_queue, skb)
3093 amount += unix_skb_len(skb);
3094 } else {
3095 skb = skb_peek(&sk->sk_receive_queue);
3096 if (skb)
3097 amount = skb->len;
3098 }
3099 spin_unlock(&sk->sk_receive_queue.lock);
3100
3101 return amount;
3102}
3103EXPORT_SYMBOL_GPL(unix_inq_len);
3104
3105long unix_outq_len(struct sock *sk)
3106{
3107 return sk_wmem_alloc_get(sk);
3108}
3109EXPORT_SYMBOL_GPL(unix_outq_len);
3110
3111static int unix_open_file(struct sock *sk)
3112{
3113 struct path path;
3114 struct file *f;
3115 int fd;
3116
3117 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
3118 return -EPERM;
3119
3120 if (!smp_load_acquire(&unix_sk(sk)->addr))
3121 return -ENOENT;
3122
3123 path = unix_sk(sk)->path;
3124 if (!path.dentry)
3125 return -ENOENT;
3126
3127 path_get(&path);
3128
3129 fd = get_unused_fd_flags(O_CLOEXEC);
3130 if (fd < 0)
3131 goto out;
3132
3133 f = dentry_open(&path, O_PATH, current_cred());
3134 if (IS_ERR(f)) {
3135 put_unused_fd(fd);
3136 fd = PTR_ERR(f);
3137 goto out;
3138 }
3139
3140 fd_install(fd, f);
3141out:
3142 path_put(&path);
3143
3144 return fd;
3145}
3146
3147static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
3148{
3149 struct sock *sk = sock->sk;
3150 long amount = 0;
3151 int err;
3152
3153 switch (cmd) {
3154 case SIOCOUTQ:
3155 amount = unix_outq_len(sk);
3156 err = put_user(amount, (int __user *)arg);
3157 break;
3158 case SIOCINQ:
3159 amount = unix_inq_len(sk);
3160 if (amount < 0)
3161 err = amount;
3162 else
3163 err = put_user(amount, (int __user *)arg);
3164 break;
3165 case SIOCUNIXFILE:
3166 err = unix_open_file(sk);
3167 break;
3168#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
3169 case SIOCATMARK:
3170 {
3171 struct unix_sock *u = unix_sk(sk);
3172 struct sk_buff *skb;
3173 int answ = 0;
3174
3175 mutex_lock(&u->iolock);
3176
3177 skb = skb_peek(&sk->sk_receive_queue);
3178 if (skb) {
3179 struct sk_buff *oob_skb = READ_ONCE(u->oob_skb);
3180 struct sk_buff *next_skb;
3181
3182 next_skb = skb_peek_next(skb, &sk->sk_receive_queue);
3183
3184 if (skb == oob_skb ||
3185 (!unix_skb_len(skb) &&
3186 (!oob_skb || next_skb == oob_skb)))
3187 answ = 1;
3188 }
3189
3190 mutex_unlock(&u->iolock);
3191
3192 err = put_user(answ, (int __user *)arg);
3193 }
3194 break;
3195#endif
3196 default:
3197 err = -ENOIOCTLCMD;
3198 break;
3199 }
3200 return err;
3201}
3202
3203#ifdef CONFIG_COMPAT
3204static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
3205{
3206 return unix_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
3207}
3208#endif
3209
3210static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait)
3211{
3212 struct sock *sk = sock->sk;
3213 unsigned char state;
3214 __poll_t mask;
3215 u8 shutdown;
3216
3217 sock_poll_wait(file, sock, wait);
3218 mask = 0;
3219 shutdown = READ_ONCE(sk->sk_shutdown);
3220 state = READ_ONCE(sk->sk_state);
3221
3222 /* exceptional events? */
3223 if (READ_ONCE(sk->sk_err))
3224 mask |= EPOLLERR;
3225 if (shutdown == SHUTDOWN_MASK)
3226 mask |= EPOLLHUP;
3227 if (shutdown & RCV_SHUTDOWN)
3228 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
3229
3230 /* readable? */
3231 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
3232 mask |= EPOLLIN | EPOLLRDNORM;
3233 if (sk_is_readable(sk))
3234 mask |= EPOLLIN | EPOLLRDNORM;
3235#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
3236 if (READ_ONCE(unix_sk(sk)->oob_skb))
3237 mask |= EPOLLPRI;
3238#endif
3239
3240 /* Connection-based need to check for termination and startup */
3241 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
3242 state == TCP_CLOSE)
3243 mask |= EPOLLHUP;
3244
3245 /*
3246 * we set writable also when the other side has shut down the
3247 * connection. This prevents stuck sockets.
3248 */
3249 if (unix_writable(sk, state))
3250 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
3251
3252 return mask;
3253}
3254
3255static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
3256 poll_table *wait)
3257{
3258 struct sock *sk = sock->sk, *other;
3259 unsigned int writable;
3260 unsigned char state;
3261 __poll_t mask;
3262 u8 shutdown;
3263
3264 sock_poll_wait(file, sock, wait);
3265 mask = 0;
3266 shutdown = READ_ONCE(sk->sk_shutdown);
3267 state = READ_ONCE(sk->sk_state);
3268
3269 /* exceptional events? */
3270 if (READ_ONCE(sk->sk_err) ||
3271 !skb_queue_empty_lockless(&sk->sk_error_queue))
3272 mask |= EPOLLERR |
3273 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
3274
3275 if (shutdown & RCV_SHUTDOWN)
3276 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
3277 if (shutdown == SHUTDOWN_MASK)
3278 mask |= EPOLLHUP;
3279
3280 /* readable? */
3281 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
3282 mask |= EPOLLIN | EPOLLRDNORM;
3283 if (sk_is_readable(sk))
3284 mask |= EPOLLIN | EPOLLRDNORM;
3285
3286 /* Connection-based need to check for termination and startup */
3287 if (sk->sk_type == SOCK_SEQPACKET && state == TCP_CLOSE)
3288 mask |= EPOLLHUP;
3289
3290 /* No write status requested, avoid expensive OUT tests. */
3291 if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT)))
3292 return mask;
3293
3294 writable = unix_writable(sk, state);
3295 if (writable) {
3296 unix_state_lock(sk);
3297
3298 other = unix_peer(sk);
3299 if (other && unix_peer(other) != sk &&
3300 unix_recvq_full_lockless(other) &&
3301 unix_dgram_peer_wake_me(sk, other))
3302 writable = 0;
3303
3304 unix_state_unlock(sk);
3305 }
3306
3307 if (writable)
3308 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
3309 else
3310 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
3311
3312 return mask;
3313}
3314
3315#ifdef CONFIG_PROC_FS
3316
3317#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
3318
3319#define get_bucket(x) ((x) >> BUCKET_SPACE)
3320#define get_offset(x) ((x) & ((1UL << BUCKET_SPACE) - 1))
3321#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
3322
3323static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
3324{
3325 unsigned long offset = get_offset(*pos);
3326 unsigned long bucket = get_bucket(*pos);
3327 unsigned long count = 0;
3328 struct sock *sk;
3329
3330 for (sk = sk_head(&seq_file_net(seq)->unx.table.buckets[bucket]);
3331 sk; sk = sk_next(sk)) {
3332 if (++count == offset)
3333 break;
3334 }
3335
3336 return sk;
3337}
3338
3339static struct sock *unix_get_first(struct seq_file *seq, loff_t *pos)
3340{
3341 unsigned long bucket = get_bucket(*pos);
3342 struct net *net = seq_file_net(seq);
3343 struct sock *sk;
3344
3345 while (bucket < UNIX_HASH_SIZE) {
3346 spin_lock(&net->unx.table.locks[bucket]);
3347
3348 sk = unix_from_bucket(seq, pos);
3349 if (sk)
3350 return sk;
3351
3352 spin_unlock(&net->unx.table.locks[bucket]);
3353
3354 *pos = set_bucket_offset(++bucket, 1);
3355 }
3356
3357 return NULL;
3358}
3359
3360static struct sock *unix_get_next(struct seq_file *seq, struct sock *sk,
3361 loff_t *pos)
3362{
3363 unsigned long bucket = get_bucket(*pos);
3364
3365 sk = sk_next(sk);
3366 if (sk)
3367 return sk;
3368
3369
3370 spin_unlock(&seq_file_net(seq)->unx.table.locks[bucket]);
3371
3372 *pos = set_bucket_offset(++bucket, 1);
3373
3374 return unix_get_first(seq, pos);
3375}
3376
3377static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
3378{
3379 if (!*pos)
3380 return SEQ_START_TOKEN;
3381
3382 return unix_get_first(seq, pos);
3383}
3384
3385static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3386{
3387 ++*pos;
3388
3389 if (v == SEQ_START_TOKEN)
3390 return unix_get_first(seq, pos);
3391
3392 return unix_get_next(seq, v, pos);
3393}
3394
3395static void unix_seq_stop(struct seq_file *seq, void *v)
3396{
3397 struct sock *sk = v;
3398
3399 if (sk)
3400 spin_unlock(&seq_file_net(seq)->unx.table.locks[sk->sk_hash]);
3401}
3402
3403static int unix_seq_show(struct seq_file *seq, void *v)
3404{
3405
3406 if (v == SEQ_START_TOKEN)
3407 seq_puts(seq, "Num RefCount Protocol Flags Type St "
3408 "Inode Path\n");
3409 else {
3410 struct sock *s = v;
3411 struct unix_sock *u = unix_sk(s);
3412 unix_state_lock(s);
3413
3414 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
3415 s,
3416 refcount_read(&s->sk_refcnt),
3417 0,
3418 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
3419 s->sk_type,
3420 s->sk_socket ?
3421 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
3422 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
3423 sock_i_ino(s));
3424
3425 if (u->addr) { // under a hash table lock here
3426 int i, len;
3427 seq_putc(seq, ' ');
3428
3429 i = 0;
3430 len = u->addr->len -
3431 offsetof(struct sockaddr_un, sun_path);
3432 if (u->addr->name->sun_path[0]) {
3433 len--;
3434 } else {
3435 seq_putc(seq, '@');
3436 i++;
3437 }
3438 for ( ; i < len; i++)
3439 seq_putc(seq, u->addr->name->sun_path[i] ?:
3440 '@');
3441 }
3442 unix_state_unlock(s);
3443 seq_putc(seq, '\n');
3444 }
3445
3446 return 0;
3447}
3448
3449static const struct seq_operations unix_seq_ops = {
3450 .start = unix_seq_start,
3451 .next = unix_seq_next,
3452 .stop = unix_seq_stop,
3453 .show = unix_seq_show,
3454};
3455
3456#ifdef CONFIG_BPF_SYSCALL
3457struct bpf_unix_iter_state {
3458 struct seq_net_private p;
3459 unsigned int cur_sk;
3460 unsigned int end_sk;
3461 unsigned int max_sk;
3462 struct sock **batch;
3463 bool st_bucket_done;
3464};
3465
3466struct bpf_iter__unix {
3467 __bpf_md_ptr(struct bpf_iter_meta *, meta);
3468 __bpf_md_ptr(struct unix_sock *, unix_sk);
3469 uid_t uid __aligned(8);
3470};
3471
3472static int unix_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
3473 struct unix_sock *unix_sk, uid_t uid)
3474{
3475 struct bpf_iter__unix ctx;
3476
3477 meta->seq_num--; /* skip SEQ_START_TOKEN */
3478 ctx.meta = meta;
3479 ctx.unix_sk = unix_sk;
3480 ctx.uid = uid;
3481 return bpf_iter_run_prog(prog, &ctx);
3482}
3483
3484static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk)
3485
3486{
3487 struct bpf_unix_iter_state *iter = seq->private;
3488 unsigned int expected = 1;
3489 struct sock *sk;
3490
3491 sock_hold(start_sk);
3492 iter->batch[iter->end_sk++] = start_sk;
3493
3494 for (sk = sk_next(start_sk); sk; sk = sk_next(sk)) {
3495 if (iter->end_sk < iter->max_sk) {
3496 sock_hold(sk);
3497 iter->batch[iter->end_sk++] = sk;
3498 }
3499
3500 expected++;
3501 }
3502
3503 spin_unlock(&seq_file_net(seq)->unx.table.locks[start_sk->sk_hash]);
3504
3505 return expected;
3506}
3507
3508static void bpf_iter_unix_put_batch(struct bpf_unix_iter_state *iter)
3509{
3510 while (iter->cur_sk < iter->end_sk)
3511 sock_put(iter->batch[iter->cur_sk++]);
3512}
3513
3514static int bpf_iter_unix_realloc_batch(struct bpf_unix_iter_state *iter,
3515 unsigned int new_batch_sz)
3516{
3517 struct sock **new_batch;
3518
3519 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3520 GFP_USER | __GFP_NOWARN);
3521 if (!new_batch)
3522 return -ENOMEM;
3523
3524 bpf_iter_unix_put_batch(iter);
3525 kvfree(iter->batch);
3526 iter->batch = new_batch;
3527 iter->max_sk = new_batch_sz;
3528
3529 return 0;
3530}
3531
3532static struct sock *bpf_iter_unix_batch(struct seq_file *seq,
3533 loff_t *pos)
3534{
3535 struct bpf_unix_iter_state *iter = seq->private;
3536 unsigned int expected;
3537 bool resized = false;
3538 struct sock *sk;
3539
3540 if (iter->st_bucket_done)
3541 *pos = set_bucket_offset(get_bucket(*pos) + 1, 1);
3542
3543again:
3544 /* Get a new batch */
3545 iter->cur_sk = 0;
3546 iter->end_sk = 0;
3547
3548 sk = unix_get_first(seq, pos);
3549 if (!sk)
3550 return NULL; /* Done */
3551
3552 expected = bpf_iter_unix_hold_batch(seq, sk);
3553
3554 if (iter->end_sk == expected) {
3555 iter->st_bucket_done = true;
3556 return sk;
3557 }
3558
3559 if (!resized && !bpf_iter_unix_realloc_batch(iter, expected * 3 / 2)) {
3560 resized = true;
3561 goto again;
3562 }
3563
3564 return sk;
3565}
3566
3567static void *bpf_iter_unix_seq_start(struct seq_file *seq, loff_t *pos)
3568{
3569 if (!*pos)
3570 return SEQ_START_TOKEN;
3571
3572 /* bpf iter does not support lseek, so it always
3573 * continue from where it was stop()-ped.
3574 */
3575 return bpf_iter_unix_batch(seq, pos);
3576}
3577
3578static void *bpf_iter_unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3579{
3580 struct bpf_unix_iter_state *iter = seq->private;
3581 struct sock *sk;
3582
3583 /* Whenever seq_next() is called, the iter->cur_sk is
3584 * done with seq_show(), so advance to the next sk in
3585 * the batch.
3586 */
3587 if (iter->cur_sk < iter->end_sk)
3588 sock_put(iter->batch[iter->cur_sk++]);
3589
3590 ++*pos;
3591
3592 if (iter->cur_sk < iter->end_sk)
3593 sk = iter->batch[iter->cur_sk];
3594 else
3595 sk = bpf_iter_unix_batch(seq, pos);
3596
3597 return sk;
3598}
3599
3600static int bpf_iter_unix_seq_show(struct seq_file *seq, void *v)
3601{
3602 struct bpf_iter_meta meta;
3603 struct bpf_prog *prog;
3604 struct sock *sk = v;
3605 uid_t uid;
3606 bool slow;
3607 int ret;
3608
3609 if (v == SEQ_START_TOKEN)
3610 return 0;
3611
3612 slow = lock_sock_fast(sk);
3613
3614 if (unlikely(sk_unhashed(sk))) {
3615 ret = SEQ_SKIP;
3616 goto unlock;
3617 }
3618
3619 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3620 meta.seq = seq;
3621 prog = bpf_iter_get_info(&meta, false);
3622 ret = unix_prog_seq_show(prog, &meta, v, uid);
3623unlock:
3624 unlock_sock_fast(sk, slow);
3625 return ret;
3626}
3627
3628static void bpf_iter_unix_seq_stop(struct seq_file *seq, void *v)
3629{
3630 struct bpf_unix_iter_state *iter = seq->private;
3631 struct bpf_iter_meta meta;
3632 struct bpf_prog *prog;
3633
3634 if (!v) {
3635 meta.seq = seq;
3636 prog = bpf_iter_get_info(&meta, true);
3637 if (prog)
3638 (void)unix_prog_seq_show(prog, &meta, v, 0);
3639 }
3640
3641 if (iter->cur_sk < iter->end_sk)
3642 bpf_iter_unix_put_batch(iter);
3643}
3644
3645static const struct seq_operations bpf_iter_unix_seq_ops = {
3646 .start = bpf_iter_unix_seq_start,
3647 .next = bpf_iter_unix_seq_next,
3648 .stop = bpf_iter_unix_seq_stop,
3649 .show = bpf_iter_unix_seq_show,
3650};
3651#endif
3652#endif
3653
3654static const struct net_proto_family unix_family_ops = {
3655 .family = PF_UNIX,
3656 .create = unix_create,
3657 .owner = THIS_MODULE,
3658};
3659
3660
3661static int __net_init unix_net_init(struct net *net)
3662{
3663 int i;
3664
3665 net->unx.sysctl_max_dgram_qlen = 10;
3666 if (unix_sysctl_register(net))
3667 goto out;
3668
3669#ifdef CONFIG_PROC_FS
3670 if (!proc_create_net("unix", 0, net->proc_net, &unix_seq_ops,
3671 sizeof(struct seq_net_private)))
3672 goto err_sysctl;
3673#endif
3674
3675 net->unx.table.locks = kvmalloc_array(UNIX_HASH_SIZE,
3676 sizeof(spinlock_t), GFP_KERNEL);
3677 if (!net->unx.table.locks)
3678 goto err_proc;
3679
3680 net->unx.table.buckets = kvmalloc_array(UNIX_HASH_SIZE,
3681 sizeof(struct hlist_head),
3682 GFP_KERNEL);
3683 if (!net->unx.table.buckets)
3684 goto free_locks;
3685
3686 for (i = 0; i < UNIX_HASH_SIZE; i++) {
3687 spin_lock_init(&net->unx.table.locks[i]);
3688 lock_set_cmp_fn(&net->unx.table.locks[i], unix_table_lock_cmp_fn, NULL);
3689 INIT_HLIST_HEAD(&net->unx.table.buckets[i]);
3690 }
3691
3692 return 0;
3693
3694free_locks:
3695 kvfree(net->unx.table.locks);
3696err_proc:
3697#ifdef CONFIG_PROC_FS
3698 remove_proc_entry("unix", net->proc_net);
3699err_sysctl:
3700#endif
3701 unix_sysctl_unregister(net);
3702out:
3703 return -ENOMEM;
3704}
3705
3706static void __net_exit unix_net_exit(struct net *net)
3707{
3708 kvfree(net->unx.table.buckets);
3709 kvfree(net->unx.table.locks);
3710 unix_sysctl_unregister(net);
3711 remove_proc_entry("unix", net->proc_net);
3712}
3713
3714static struct pernet_operations unix_net_ops = {
3715 .init = unix_net_init,
3716 .exit = unix_net_exit,
3717};
3718
3719#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3720DEFINE_BPF_ITER_FUNC(unix, struct bpf_iter_meta *meta,
3721 struct unix_sock *unix_sk, uid_t uid)
3722
3723#define INIT_BATCH_SZ 16
3724
3725static int bpf_iter_init_unix(void *priv_data, struct bpf_iter_aux_info *aux)
3726{
3727 struct bpf_unix_iter_state *iter = priv_data;
3728 int err;
3729
3730 err = bpf_iter_init_seq_net(priv_data, aux);
3731 if (err)
3732 return err;
3733
3734 err = bpf_iter_unix_realloc_batch(iter, INIT_BATCH_SZ);
3735 if (err) {
3736 bpf_iter_fini_seq_net(priv_data);
3737 return err;
3738 }
3739
3740 return 0;
3741}
3742
3743static void bpf_iter_fini_unix(void *priv_data)
3744{
3745 struct bpf_unix_iter_state *iter = priv_data;
3746
3747 bpf_iter_fini_seq_net(priv_data);
3748 kvfree(iter->batch);
3749}
3750
3751static const struct bpf_iter_seq_info unix_seq_info = {
3752 .seq_ops = &bpf_iter_unix_seq_ops,
3753 .init_seq_private = bpf_iter_init_unix,
3754 .fini_seq_private = bpf_iter_fini_unix,
3755 .seq_priv_size = sizeof(struct bpf_unix_iter_state),
3756};
3757
3758static const struct bpf_func_proto *
3759bpf_iter_unix_get_func_proto(enum bpf_func_id func_id,
3760 const struct bpf_prog *prog)
3761{
3762 switch (func_id) {
3763 case BPF_FUNC_setsockopt:
3764 return &bpf_sk_setsockopt_proto;
3765 case BPF_FUNC_getsockopt:
3766 return &bpf_sk_getsockopt_proto;
3767 default:
3768 return NULL;
3769 }
3770}
3771
3772static struct bpf_iter_reg unix_reg_info = {
3773 .target = "unix",
3774 .ctx_arg_info_size = 1,
3775 .ctx_arg_info = {
3776 { offsetof(struct bpf_iter__unix, unix_sk),
3777 PTR_TO_BTF_ID_OR_NULL },
3778 },
3779 .get_func_proto = bpf_iter_unix_get_func_proto,
3780 .seq_info = &unix_seq_info,
3781};
3782
3783static void __init bpf_iter_register(void)
3784{
3785 unix_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UNIX];
3786 if (bpf_iter_reg_target(&unix_reg_info))
3787 pr_warn("Warning: could not register bpf iterator unix\n");
3788}
3789#endif
3790
3791static int __init af_unix_init(void)
3792{
3793 int i, rc = -1;
3794
3795 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb));
3796
3797 for (i = 0; i < UNIX_HASH_SIZE / 2; i++) {
3798 spin_lock_init(&bsd_socket_locks[i]);
3799 INIT_HLIST_HEAD(&bsd_socket_buckets[i]);
3800 }
3801
3802 rc = proto_register(&unix_dgram_proto, 1);
3803 if (rc != 0) {
3804 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
3805 goto out;
3806 }
3807
3808 rc = proto_register(&unix_stream_proto, 1);
3809 if (rc != 0) {
3810 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
3811 proto_unregister(&unix_dgram_proto);
3812 goto out;
3813 }
3814
3815 sock_register(&unix_family_ops);
3816 register_pernet_subsys(&unix_net_ops);
3817 unix_bpf_build_proto();
3818
3819#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3820 bpf_iter_register();
3821#endif
3822
3823out:
3824 return rc;
3825}
3826
3827/* Later than subsys_initcall() because we depend on stuff initialised there */
3828fs_initcall(af_unix_init);
1/*
2 * NET4: Implementation of BSD Unix domain sockets.
3 *
4 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * Fixes:
12 * Linus Torvalds : Assorted bug cures.
13 * Niibe Yutaka : async I/O support.
14 * Carsten Paeth : PF_UNIX check, address fixes.
15 * Alan Cox : Limit size of allocated blocks.
16 * Alan Cox : Fixed the stupid socketpair bug.
17 * Alan Cox : BSD compatibility fine tuning.
18 * Alan Cox : Fixed a bug in connect when interrupted.
19 * Alan Cox : Sorted out a proper draft version of
20 * file descriptor passing hacked up from
21 * Mike Shaver's work.
22 * Marty Leisner : Fixes to fd passing
23 * Nick Nevin : recvmsg bugfix.
24 * Alan Cox : Started proper garbage collector
25 * Heiko EiBfeldt : Missing verify_area check
26 * Alan Cox : Started POSIXisms
27 * Andreas Schwab : Replace inode by dentry for proper
28 * reference counting
29 * Kirk Petersen : Made this a module
30 * Christoph Rohland : Elegant non-blocking accept/connect algorithm.
31 * Lots of bug fixes.
32 * Alexey Kuznetosv : Repaired (I hope) bugs introduces
33 * by above two patches.
34 * Andrea Arcangeli : If possible we block in connect(2)
35 * if the max backlog of the listen socket
36 * is been reached. This won't break
37 * old apps and it will avoid huge amount
38 * of socks hashed (this for unix_gc()
39 * performances reasons).
40 * Security fix that limits the max
41 * number of socks to 2*max_files and
42 * the number of skb queueable in the
43 * dgram receiver.
44 * Artur Skawina : Hash function optimizations
45 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
46 * Malcolm Beattie : Set peercred for socketpair
47 * Michal Ostrowski : Module initialization cleanup.
48 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT,
49 * the core infrastructure is doing that
50 * for all net proto families now (2.5.69+)
51 *
52 *
53 * Known differences from reference BSD that was tested:
54 *
55 * [TO FIX]
56 * ECONNREFUSED is not returned from one end of a connected() socket to the
57 * other the moment one end closes.
58 * fstat() doesn't return st_dev=0, and give the blksize as high water mark
59 * and a fake inode identifier (nor the BSD first socket fstat twice bug).
60 * [NOT TO FIX]
61 * accept() returns a path name even if the connecting socket has closed
62 * in the meantime (BSD loses the path and gives up).
63 * accept() returns 0 length path for an unbound connector. BSD returns 16
64 * and a null first byte in the path (but not for gethost/peername - BSD bug ??)
65 * socketpair(...SOCK_RAW..) doesn't panic the kernel.
66 * BSD af_unix apparently has connect forgetting to block properly.
67 * (need to check this with the POSIX spec in detail)
68 *
69 * Differences from 2.0.0-11-... (ANK)
70 * Bug fixes and improvements.
71 * - client shutdown killed server socket.
72 * - removed all useless cli/sti pairs.
73 *
74 * Semantic changes/extensions.
75 * - generic control message passing.
76 * - SCM_CREDENTIALS control message.
77 * - "Abstract" (not FS based) socket bindings.
78 * Abstract names are sequences of bytes (not zero terminated)
79 * started by 0, so that this name space does not intersect
80 * with BSD names.
81 */
82
83#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
84
85#include <linux/module.h>
86#include <linux/kernel.h>
87#include <linux/signal.h>
88#include <linux/sched/signal.h>
89#include <linux/errno.h>
90#include <linux/string.h>
91#include <linux/stat.h>
92#include <linux/dcache.h>
93#include <linux/namei.h>
94#include <linux/socket.h>
95#include <linux/un.h>
96#include <linux/fcntl.h>
97#include <linux/termios.h>
98#include <linux/sockios.h>
99#include <linux/net.h>
100#include <linux/in.h>
101#include <linux/fs.h>
102#include <linux/slab.h>
103#include <linux/uaccess.h>
104#include <linux/skbuff.h>
105#include <linux/netdevice.h>
106#include <net/net_namespace.h>
107#include <net/sock.h>
108#include <net/tcp_states.h>
109#include <net/af_unix.h>
110#include <linux/proc_fs.h>
111#include <linux/seq_file.h>
112#include <net/scm.h>
113#include <linux/init.h>
114#include <linux/poll.h>
115#include <linux/rtnetlink.h>
116#include <linux/mount.h>
117#include <net/checksum.h>
118#include <linux/security.h>
119#include <linux/freezer.h>
120#include <linux/file.h>
121
122struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
123EXPORT_SYMBOL_GPL(unix_socket_table);
124DEFINE_SPINLOCK(unix_table_lock);
125EXPORT_SYMBOL_GPL(unix_table_lock);
126static atomic_long_t unix_nr_socks;
127
128
129static struct hlist_head *unix_sockets_unbound(void *addr)
130{
131 unsigned long hash = (unsigned long)addr;
132
133 hash ^= hash >> 16;
134 hash ^= hash >> 8;
135 hash %= UNIX_HASH_SIZE;
136 return &unix_socket_table[UNIX_HASH_SIZE + hash];
137}
138
139#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
140
141#ifdef CONFIG_SECURITY_NETWORK
142static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
143{
144 UNIXCB(skb).secid = scm->secid;
145}
146
147static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
148{
149 scm->secid = UNIXCB(skb).secid;
150}
151
152static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
153{
154 return (scm->secid == UNIXCB(skb).secid);
155}
156#else
157static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
158{ }
159
160static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
161{ }
162
163static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
164{
165 return true;
166}
167#endif /* CONFIG_SECURITY_NETWORK */
168
169/*
170 * SMP locking strategy:
171 * hash table is protected with spinlock unix_table_lock
172 * each socket state is protected by separate spin lock.
173 */
174
175static inline unsigned int unix_hash_fold(__wsum n)
176{
177 unsigned int hash = (__force unsigned int)csum_fold(n);
178
179 hash ^= hash>>8;
180 return hash&(UNIX_HASH_SIZE-1);
181}
182
183#define unix_peer(sk) (unix_sk(sk)->peer)
184
185static inline int unix_our_peer(struct sock *sk, struct sock *osk)
186{
187 return unix_peer(osk) == sk;
188}
189
190static inline int unix_may_send(struct sock *sk, struct sock *osk)
191{
192 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
193}
194
195static inline int unix_recvq_full(struct sock const *sk)
196{
197 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
198}
199
200struct sock *unix_peer_get(struct sock *s)
201{
202 struct sock *peer;
203
204 unix_state_lock(s);
205 peer = unix_peer(s);
206 if (peer)
207 sock_hold(peer);
208 unix_state_unlock(s);
209 return peer;
210}
211EXPORT_SYMBOL_GPL(unix_peer_get);
212
213static inline void unix_release_addr(struct unix_address *addr)
214{
215 if (refcount_dec_and_test(&addr->refcnt))
216 kfree(addr);
217}
218
219/*
220 * Check unix socket name:
221 * - should be not zero length.
222 * - if started by not zero, should be NULL terminated (FS object)
223 * - if started by zero, it is abstract name.
224 */
225
226static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
227{
228 if (len <= sizeof(short) || len > sizeof(*sunaddr))
229 return -EINVAL;
230 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
231 return -EINVAL;
232 if (sunaddr->sun_path[0]) {
233 /*
234 * This may look like an off by one error but it is a bit more
235 * subtle. 108 is the longest valid AF_UNIX path for a binding.
236 * sun_path[108] doesn't as such exist. However in kernel space
237 * we are guaranteed that it is a valid memory location in our
238 * kernel address buffer.
239 */
240 ((char *)sunaddr)[len] = 0;
241 len = strlen(sunaddr->sun_path)+1+sizeof(short);
242 return len;
243 }
244
245 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
246 return len;
247}
248
249static void __unix_remove_socket(struct sock *sk)
250{
251 sk_del_node_init(sk);
252}
253
254static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
255{
256 WARN_ON(!sk_unhashed(sk));
257 sk_add_node(sk, list);
258}
259
260static inline void unix_remove_socket(struct sock *sk)
261{
262 spin_lock(&unix_table_lock);
263 __unix_remove_socket(sk);
264 spin_unlock(&unix_table_lock);
265}
266
267static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
268{
269 spin_lock(&unix_table_lock);
270 __unix_insert_socket(list, sk);
271 spin_unlock(&unix_table_lock);
272}
273
274static struct sock *__unix_find_socket_byname(struct net *net,
275 struct sockaddr_un *sunname,
276 int len, int type, unsigned int hash)
277{
278 struct sock *s;
279
280 sk_for_each(s, &unix_socket_table[hash ^ type]) {
281 struct unix_sock *u = unix_sk(s);
282
283 if (!net_eq(sock_net(s), net))
284 continue;
285
286 if (u->addr->len == len &&
287 !memcmp(u->addr->name, sunname, len))
288 goto found;
289 }
290 s = NULL;
291found:
292 return s;
293}
294
295static inline struct sock *unix_find_socket_byname(struct net *net,
296 struct sockaddr_un *sunname,
297 int len, int type,
298 unsigned int hash)
299{
300 struct sock *s;
301
302 spin_lock(&unix_table_lock);
303 s = __unix_find_socket_byname(net, sunname, len, type, hash);
304 if (s)
305 sock_hold(s);
306 spin_unlock(&unix_table_lock);
307 return s;
308}
309
310static struct sock *unix_find_socket_byinode(struct inode *i)
311{
312 struct sock *s;
313
314 spin_lock(&unix_table_lock);
315 sk_for_each(s,
316 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
317 struct dentry *dentry = unix_sk(s)->path.dentry;
318
319 if (dentry && d_backing_inode(dentry) == i) {
320 sock_hold(s);
321 goto found;
322 }
323 }
324 s = NULL;
325found:
326 spin_unlock(&unix_table_lock);
327 return s;
328}
329
330/* Support code for asymmetrically connected dgram sockets
331 *
332 * If a datagram socket is connected to a socket not itself connected
333 * to the first socket (eg, /dev/log), clients may only enqueue more
334 * messages if the present receive queue of the server socket is not
335 * "too large". This means there's a second writeability condition
336 * poll and sendmsg need to test. The dgram recv code will do a wake
337 * up on the peer_wait wait queue of a socket upon reception of a
338 * datagram which needs to be propagated to sleeping would-be writers
339 * since these might not have sent anything so far. This can't be
340 * accomplished via poll_wait because the lifetime of the server
341 * socket might be less than that of its clients if these break their
342 * association with it or if the server socket is closed while clients
343 * are still connected to it and there's no way to inform "a polling
344 * implementation" that it should let go of a certain wait queue
345 *
346 * In order to propagate a wake up, a wait_queue_entry_t of the client
347 * socket is enqueued on the peer_wait queue of the server socket
348 * whose wake function does a wake_up on the ordinary client socket
349 * wait queue. This connection is established whenever a write (or
350 * poll for write) hit the flow control condition and broken when the
351 * association to the server socket is dissolved or after a wake up
352 * was relayed.
353 */
354
355static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
356 void *key)
357{
358 struct unix_sock *u;
359 wait_queue_head_t *u_sleep;
360
361 u = container_of(q, struct unix_sock, peer_wake);
362
363 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
364 q);
365 u->peer_wake.private = NULL;
366
367 /* relaying can only happen while the wq still exists */
368 u_sleep = sk_sleep(&u->sk);
369 if (u_sleep)
370 wake_up_interruptible_poll(u_sleep, key_to_poll(key));
371
372 return 0;
373}
374
375static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
376{
377 struct unix_sock *u, *u_other;
378 int rc;
379
380 u = unix_sk(sk);
381 u_other = unix_sk(other);
382 rc = 0;
383 spin_lock(&u_other->peer_wait.lock);
384
385 if (!u->peer_wake.private) {
386 u->peer_wake.private = other;
387 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
388
389 rc = 1;
390 }
391
392 spin_unlock(&u_other->peer_wait.lock);
393 return rc;
394}
395
396static void unix_dgram_peer_wake_disconnect(struct sock *sk,
397 struct sock *other)
398{
399 struct unix_sock *u, *u_other;
400
401 u = unix_sk(sk);
402 u_other = unix_sk(other);
403 spin_lock(&u_other->peer_wait.lock);
404
405 if (u->peer_wake.private == other) {
406 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
407 u->peer_wake.private = NULL;
408 }
409
410 spin_unlock(&u_other->peer_wait.lock);
411}
412
413static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
414 struct sock *other)
415{
416 unix_dgram_peer_wake_disconnect(sk, other);
417 wake_up_interruptible_poll(sk_sleep(sk),
418 EPOLLOUT |
419 EPOLLWRNORM |
420 EPOLLWRBAND);
421}
422
423/* preconditions:
424 * - unix_peer(sk) == other
425 * - association is stable
426 */
427static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
428{
429 int connected;
430
431 connected = unix_dgram_peer_wake_connect(sk, other);
432
433 if (unix_recvq_full(other))
434 return 1;
435
436 if (connected)
437 unix_dgram_peer_wake_disconnect(sk, other);
438
439 return 0;
440}
441
442static int unix_writable(const struct sock *sk)
443{
444 return sk->sk_state != TCP_LISTEN &&
445 (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
446}
447
448static void unix_write_space(struct sock *sk)
449{
450 struct socket_wq *wq;
451
452 rcu_read_lock();
453 if (unix_writable(sk)) {
454 wq = rcu_dereference(sk->sk_wq);
455 if (skwq_has_sleeper(wq))
456 wake_up_interruptible_sync_poll(&wq->wait,
457 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
458 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
459 }
460 rcu_read_unlock();
461}
462
463/* When dgram socket disconnects (or changes its peer), we clear its receive
464 * queue of packets arrived from previous peer. First, it allows to do
465 * flow control based only on wmem_alloc; second, sk connected to peer
466 * may receive messages only from that peer. */
467static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
468{
469 if (!skb_queue_empty(&sk->sk_receive_queue)) {
470 skb_queue_purge(&sk->sk_receive_queue);
471 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
472
473 /* If one link of bidirectional dgram pipe is disconnected,
474 * we signal error. Messages are lost. Do not make this,
475 * when peer was not connected to us.
476 */
477 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
478 other->sk_err = ECONNRESET;
479 other->sk_error_report(other);
480 }
481 }
482}
483
484static void unix_sock_destructor(struct sock *sk)
485{
486 struct unix_sock *u = unix_sk(sk);
487
488 skb_queue_purge(&sk->sk_receive_queue);
489
490 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
491 WARN_ON(!sk_unhashed(sk));
492 WARN_ON(sk->sk_socket);
493 if (!sock_flag(sk, SOCK_DEAD)) {
494 pr_info("Attempt to release alive unix socket: %p\n", sk);
495 return;
496 }
497
498 if (u->addr)
499 unix_release_addr(u->addr);
500
501 atomic_long_dec(&unix_nr_socks);
502 local_bh_disable();
503 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
504 local_bh_enable();
505#ifdef UNIX_REFCNT_DEBUG
506 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
507 atomic_long_read(&unix_nr_socks));
508#endif
509}
510
511static void unix_release_sock(struct sock *sk, int embrion)
512{
513 struct unix_sock *u = unix_sk(sk);
514 struct path path;
515 struct sock *skpair;
516 struct sk_buff *skb;
517 int state;
518
519 unix_remove_socket(sk);
520
521 /* Clear state */
522 unix_state_lock(sk);
523 sock_orphan(sk);
524 sk->sk_shutdown = SHUTDOWN_MASK;
525 path = u->path;
526 u->path.dentry = NULL;
527 u->path.mnt = NULL;
528 state = sk->sk_state;
529 sk->sk_state = TCP_CLOSE;
530 unix_state_unlock(sk);
531
532 wake_up_interruptible_all(&u->peer_wait);
533
534 skpair = unix_peer(sk);
535
536 if (skpair != NULL) {
537 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
538 unix_state_lock(skpair);
539 /* No more writes */
540 skpair->sk_shutdown = SHUTDOWN_MASK;
541 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
542 skpair->sk_err = ECONNRESET;
543 unix_state_unlock(skpair);
544 skpair->sk_state_change(skpair);
545 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
546 }
547
548 unix_dgram_peer_wake_disconnect(sk, skpair);
549 sock_put(skpair); /* It may now die */
550 unix_peer(sk) = NULL;
551 }
552
553 /* Try to flush out this socket. Throw out buffers at least */
554
555 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
556 if (state == TCP_LISTEN)
557 unix_release_sock(skb->sk, 1);
558 /* passed fds are erased in the kfree_skb hook */
559 UNIXCB(skb).consumed = skb->len;
560 kfree_skb(skb);
561 }
562
563 if (path.dentry)
564 path_put(&path);
565
566 sock_put(sk);
567
568 /* ---- Socket is dead now and most probably destroyed ---- */
569
570 /*
571 * Fixme: BSD difference: In BSD all sockets connected to us get
572 * ECONNRESET and we die on the spot. In Linux we behave
573 * like files and pipes do and wait for the last
574 * dereference.
575 *
576 * Can't we simply set sock->err?
577 *
578 * What the above comment does talk about? --ANK(980817)
579 */
580
581 if (unix_tot_inflight)
582 unix_gc(); /* Garbage collect fds */
583}
584
585static void init_peercred(struct sock *sk)
586{
587 put_pid(sk->sk_peer_pid);
588 if (sk->sk_peer_cred)
589 put_cred(sk->sk_peer_cred);
590 sk->sk_peer_pid = get_pid(task_tgid(current));
591 sk->sk_peer_cred = get_current_cred();
592}
593
594static void copy_peercred(struct sock *sk, struct sock *peersk)
595{
596 put_pid(sk->sk_peer_pid);
597 if (sk->sk_peer_cred)
598 put_cred(sk->sk_peer_cred);
599 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
600 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
601}
602
603static int unix_listen(struct socket *sock, int backlog)
604{
605 int err;
606 struct sock *sk = sock->sk;
607 struct unix_sock *u = unix_sk(sk);
608 struct pid *old_pid = NULL;
609
610 err = -EOPNOTSUPP;
611 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
612 goto out; /* Only stream/seqpacket sockets accept */
613 err = -EINVAL;
614 if (!u->addr)
615 goto out; /* No listens on an unbound socket */
616 unix_state_lock(sk);
617 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
618 goto out_unlock;
619 if (backlog > sk->sk_max_ack_backlog)
620 wake_up_interruptible_all(&u->peer_wait);
621 sk->sk_max_ack_backlog = backlog;
622 sk->sk_state = TCP_LISTEN;
623 /* set credentials so connect can copy them */
624 init_peercred(sk);
625 err = 0;
626
627out_unlock:
628 unix_state_unlock(sk);
629 put_pid(old_pid);
630out:
631 return err;
632}
633
634static int unix_release(struct socket *);
635static int unix_bind(struct socket *, struct sockaddr *, int);
636static int unix_stream_connect(struct socket *, struct sockaddr *,
637 int addr_len, int flags);
638static int unix_socketpair(struct socket *, struct socket *);
639static int unix_accept(struct socket *, struct socket *, int, bool);
640static int unix_getname(struct socket *, struct sockaddr *, int);
641static __poll_t unix_poll(struct file *, struct socket *, poll_table *);
642static __poll_t unix_dgram_poll(struct file *, struct socket *,
643 poll_table *);
644static int unix_ioctl(struct socket *, unsigned int, unsigned long);
645static int unix_shutdown(struct socket *, int);
646static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
647static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
648static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
649 size_t size, int flags);
650static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
651 struct pipe_inode_info *, size_t size,
652 unsigned int flags);
653static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
654static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
655static int unix_dgram_connect(struct socket *, struct sockaddr *,
656 int, int);
657static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
658static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
659 int);
660
661static int unix_set_peek_off(struct sock *sk, int val)
662{
663 struct unix_sock *u = unix_sk(sk);
664
665 if (mutex_lock_interruptible(&u->iolock))
666 return -EINTR;
667
668 sk->sk_peek_off = val;
669 mutex_unlock(&u->iolock);
670
671 return 0;
672}
673
674
675static const struct proto_ops unix_stream_ops = {
676 .family = PF_UNIX,
677 .owner = THIS_MODULE,
678 .release = unix_release,
679 .bind = unix_bind,
680 .connect = unix_stream_connect,
681 .socketpair = unix_socketpair,
682 .accept = unix_accept,
683 .getname = unix_getname,
684 .poll = unix_poll,
685 .ioctl = unix_ioctl,
686 .listen = unix_listen,
687 .shutdown = unix_shutdown,
688 .setsockopt = sock_no_setsockopt,
689 .getsockopt = sock_no_getsockopt,
690 .sendmsg = unix_stream_sendmsg,
691 .recvmsg = unix_stream_recvmsg,
692 .mmap = sock_no_mmap,
693 .sendpage = unix_stream_sendpage,
694 .splice_read = unix_stream_splice_read,
695 .set_peek_off = unix_set_peek_off,
696};
697
698static const struct proto_ops unix_dgram_ops = {
699 .family = PF_UNIX,
700 .owner = THIS_MODULE,
701 .release = unix_release,
702 .bind = unix_bind,
703 .connect = unix_dgram_connect,
704 .socketpair = unix_socketpair,
705 .accept = sock_no_accept,
706 .getname = unix_getname,
707 .poll = unix_dgram_poll,
708 .ioctl = unix_ioctl,
709 .listen = sock_no_listen,
710 .shutdown = unix_shutdown,
711 .setsockopt = sock_no_setsockopt,
712 .getsockopt = sock_no_getsockopt,
713 .sendmsg = unix_dgram_sendmsg,
714 .recvmsg = unix_dgram_recvmsg,
715 .mmap = sock_no_mmap,
716 .sendpage = sock_no_sendpage,
717 .set_peek_off = unix_set_peek_off,
718};
719
720static const struct proto_ops unix_seqpacket_ops = {
721 .family = PF_UNIX,
722 .owner = THIS_MODULE,
723 .release = unix_release,
724 .bind = unix_bind,
725 .connect = unix_stream_connect,
726 .socketpair = unix_socketpair,
727 .accept = unix_accept,
728 .getname = unix_getname,
729 .poll = unix_dgram_poll,
730 .ioctl = unix_ioctl,
731 .listen = unix_listen,
732 .shutdown = unix_shutdown,
733 .setsockopt = sock_no_setsockopt,
734 .getsockopt = sock_no_getsockopt,
735 .sendmsg = unix_seqpacket_sendmsg,
736 .recvmsg = unix_seqpacket_recvmsg,
737 .mmap = sock_no_mmap,
738 .sendpage = sock_no_sendpage,
739 .set_peek_off = unix_set_peek_off,
740};
741
742static struct proto unix_proto = {
743 .name = "UNIX",
744 .owner = THIS_MODULE,
745 .obj_size = sizeof(struct unix_sock),
746};
747
748static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
749{
750 struct sock *sk = NULL;
751 struct unix_sock *u;
752
753 atomic_long_inc(&unix_nr_socks);
754 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
755 goto out;
756
757 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
758 if (!sk)
759 goto out;
760
761 sock_init_data(sock, sk);
762
763 sk->sk_allocation = GFP_KERNEL_ACCOUNT;
764 sk->sk_write_space = unix_write_space;
765 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
766 sk->sk_destruct = unix_sock_destructor;
767 u = unix_sk(sk);
768 u->path.dentry = NULL;
769 u->path.mnt = NULL;
770 spin_lock_init(&u->lock);
771 atomic_long_set(&u->inflight, 0);
772 INIT_LIST_HEAD(&u->link);
773 mutex_init(&u->iolock); /* single task reading lock */
774 mutex_init(&u->bindlock); /* single task binding lock */
775 init_waitqueue_head(&u->peer_wait);
776 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
777 unix_insert_socket(unix_sockets_unbound(sk), sk);
778out:
779 if (sk == NULL)
780 atomic_long_dec(&unix_nr_socks);
781 else {
782 local_bh_disable();
783 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
784 local_bh_enable();
785 }
786 return sk;
787}
788
789static int unix_create(struct net *net, struct socket *sock, int protocol,
790 int kern)
791{
792 if (protocol && protocol != PF_UNIX)
793 return -EPROTONOSUPPORT;
794
795 sock->state = SS_UNCONNECTED;
796
797 switch (sock->type) {
798 case SOCK_STREAM:
799 sock->ops = &unix_stream_ops;
800 break;
801 /*
802 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
803 * nothing uses it.
804 */
805 case SOCK_RAW:
806 sock->type = SOCK_DGRAM;
807 /* fall through */
808 case SOCK_DGRAM:
809 sock->ops = &unix_dgram_ops;
810 break;
811 case SOCK_SEQPACKET:
812 sock->ops = &unix_seqpacket_ops;
813 break;
814 default:
815 return -ESOCKTNOSUPPORT;
816 }
817
818 return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
819}
820
821static int unix_release(struct socket *sock)
822{
823 struct sock *sk = sock->sk;
824
825 if (!sk)
826 return 0;
827
828 unix_release_sock(sk, 0);
829 sock->sk = NULL;
830
831 return 0;
832}
833
834static int unix_autobind(struct socket *sock)
835{
836 struct sock *sk = sock->sk;
837 struct net *net = sock_net(sk);
838 struct unix_sock *u = unix_sk(sk);
839 static u32 ordernum = 1;
840 struct unix_address *addr;
841 int err;
842 unsigned int retries = 0;
843
844 err = mutex_lock_interruptible(&u->bindlock);
845 if (err)
846 return err;
847
848 err = 0;
849 if (u->addr)
850 goto out;
851
852 err = -ENOMEM;
853 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
854 if (!addr)
855 goto out;
856
857 addr->name->sun_family = AF_UNIX;
858 refcount_set(&addr->refcnt, 1);
859
860retry:
861 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
862 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
863
864 spin_lock(&unix_table_lock);
865 ordernum = (ordernum+1)&0xFFFFF;
866
867 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
868 addr->hash)) {
869 spin_unlock(&unix_table_lock);
870 /*
871 * __unix_find_socket_byname() may take long time if many names
872 * are already in use.
873 */
874 cond_resched();
875 /* Give up if all names seems to be in use. */
876 if (retries++ == 0xFFFFF) {
877 err = -ENOSPC;
878 kfree(addr);
879 goto out;
880 }
881 goto retry;
882 }
883 addr->hash ^= sk->sk_type;
884
885 __unix_remove_socket(sk);
886 u->addr = addr;
887 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
888 spin_unlock(&unix_table_lock);
889 err = 0;
890
891out: mutex_unlock(&u->bindlock);
892 return err;
893}
894
895static struct sock *unix_find_other(struct net *net,
896 struct sockaddr_un *sunname, int len,
897 int type, unsigned int hash, int *error)
898{
899 struct sock *u;
900 struct path path;
901 int err = 0;
902
903 if (sunname->sun_path[0]) {
904 struct inode *inode;
905 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
906 if (err)
907 goto fail;
908 inode = d_backing_inode(path.dentry);
909 err = inode_permission(inode, MAY_WRITE);
910 if (err)
911 goto put_fail;
912
913 err = -ECONNREFUSED;
914 if (!S_ISSOCK(inode->i_mode))
915 goto put_fail;
916 u = unix_find_socket_byinode(inode);
917 if (!u)
918 goto put_fail;
919
920 if (u->sk_type == type)
921 touch_atime(&path);
922
923 path_put(&path);
924
925 err = -EPROTOTYPE;
926 if (u->sk_type != type) {
927 sock_put(u);
928 goto fail;
929 }
930 } else {
931 err = -ECONNREFUSED;
932 u = unix_find_socket_byname(net, sunname, len, type, hash);
933 if (u) {
934 struct dentry *dentry;
935 dentry = unix_sk(u)->path.dentry;
936 if (dentry)
937 touch_atime(&unix_sk(u)->path);
938 } else
939 goto fail;
940 }
941 return u;
942
943put_fail:
944 path_put(&path);
945fail:
946 *error = err;
947 return NULL;
948}
949
950static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
951{
952 struct dentry *dentry;
953 struct path path;
954 int err = 0;
955 /*
956 * Get the parent directory, calculate the hash for last
957 * component.
958 */
959 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
960 err = PTR_ERR(dentry);
961 if (IS_ERR(dentry))
962 return err;
963
964 /*
965 * All right, let's create it.
966 */
967 err = security_path_mknod(&path, dentry, mode, 0);
968 if (!err) {
969 err = vfs_mknod(d_inode(path.dentry), dentry, mode, 0);
970 if (!err) {
971 res->mnt = mntget(path.mnt);
972 res->dentry = dget(dentry);
973 }
974 }
975 done_path_create(&path, dentry);
976 return err;
977}
978
979static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
980{
981 struct sock *sk = sock->sk;
982 struct net *net = sock_net(sk);
983 struct unix_sock *u = unix_sk(sk);
984 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
985 char *sun_path = sunaddr->sun_path;
986 int err;
987 unsigned int hash;
988 struct unix_address *addr;
989 struct hlist_head *list;
990 struct path path = { };
991
992 err = -EINVAL;
993 if (addr_len < offsetofend(struct sockaddr_un, sun_family) ||
994 sunaddr->sun_family != AF_UNIX)
995 goto out;
996
997 if (addr_len == sizeof(short)) {
998 err = unix_autobind(sock);
999 goto out;
1000 }
1001
1002 err = unix_mkname(sunaddr, addr_len, &hash);
1003 if (err < 0)
1004 goto out;
1005 addr_len = err;
1006
1007 if (sun_path[0]) {
1008 umode_t mode = S_IFSOCK |
1009 (SOCK_INODE(sock)->i_mode & ~current_umask());
1010 err = unix_mknod(sun_path, mode, &path);
1011 if (err) {
1012 if (err == -EEXIST)
1013 err = -EADDRINUSE;
1014 goto out;
1015 }
1016 }
1017
1018 err = mutex_lock_interruptible(&u->bindlock);
1019 if (err)
1020 goto out_put;
1021
1022 err = -EINVAL;
1023 if (u->addr)
1024 goto out_up;
1025
1026 err = -ENOMEM;
1027 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
1028 if (!addr)
1029 goto out_up;
1030
1031 memcpy(addr->name, sunaddr, addr_len);
1032 addr->len = addr_len;
1033 addr->hash = hash ^ sk->sk_type;
1034 refcount_set(&addr->refcnt, 1);
1035
1036 if (sun_path[0]) {
1037 addr->hash = UNIX_HASH_SIZE;
1038 hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE - 1);
1039 spin_lock(&unix_table_lock);
1040 u->path = path;
1041 list = &unix_socket_table[hash];
1042 } else {
1043 spin_lock(&unix_table_lock);
1044 err = -EADDRINUSE;
1045 if (__unix_find_socket_byname(net, sunaddr, addr_len,
1046 sk->sk_type, hash)) {
1047 unix_release_addr(addr);
1048 goto out_unlock;
1049 }
1050
1051 list = &unix_socket_table[addr->hash];
1052 }
1053
1054 err = 0;
1055 __unix_remove_socket(sk);
1056 u->addr = addr;
1057 __unix_insert_socket(list, sk);
1058
1059out_unlock:
1060 spin_unlock(&unix_table_lock);
1061out_up:
1062 mutex_unlock(&u->bindlock);
1063out_put:
1064 if (err)
1065 path_put(&path);
1066out:
1067 return err;
1068}
1069
1070static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1071{
1072 if (unlikely(sk1 == sk2) || !sk2) {
1073 unix_state_lock(sk1);
1074 return;
1075 }
1076 if (sk1 < sk2) {
1077 unix_state_lock(sk1);
1078 unix_state_lock_nested(sk2);
1079 } else {
1080 unix_state_lock(sk2);
1081 unix_state_lock_nested(sk1);
1082 }
1083}
1084
1085static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1086{
1087 if (unlikely(sk1 == sk2) || !sk2) {
1088 unix_state_unlock(sk1);
1089 return;
1090 }
1091 unix_state_unlock(sk1);
1092 unix_state_unlock(sk2);
1093}
1094
1095static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1096 int alen, int flags)
1097{
1098 struct sock *sk = sock->sk;
1099 struct net *net = sock_net(sk);
1100 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1101 struct sock *other;
1102 unsigned int hash;
1103 int err;
1104
1105 err = -EINVAL;
1106 if (alen < offsetofend(struct sockaddr, sa_family))
1107 goto out;
1108
1109 if (addr->sa_family != AF_UNSPEC) {
1110 err = unix_mkname(sunaddr, alen, &hash);
1111 if (err < 0)
1112 goto out;
1113 alen = err;
1114
1115 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1116 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1117 goto out;
1118
1119restart:
1120 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1121 if (!other)
1122 goto out;
1123
1124 unix_state_double_lock(sk, other);
1125
1126 /* Apparently VFS overslept socket death. Retry. */
1127 if (sock_flag(other, SOCK_DEAD)) {
1128 unix_state_double_unlock(sk, other);
1129 sock_put(other);
1130 goto restart;
1131 }
1132
1133 err = -EPERM;
1134 if (!unix_may_send(sk, other))
1135 goto out_unlock;
1136
1137 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1138 if (err)
1139 goto out_unlock;
1140
1141 } else {
1142 /*
1143 * 1003.1g breaking connected state with AF_UNSPEC
1144 */
1145 other = NULL;
1146 unix_state_double_lock(sk, other);
1147 }
1148
1149 /*
1150 * If it was connected, reconnect.
1151 */
1152 if (unix_peer(sk)) {
1153 struct sock *old_peer = unix_peer(sk);
1154 unix_peer(sk) = other;
1155 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1156
1157 unix_state_double_unlock(sk, other);
1158
1159 if (other != old_peer)
1160 unix_dgram_disconnected(sk, old_peer);
1161 sock_put(old_peer);
1162 } else {
1163 unix_peer(sk) = other;
1164 unix_state_double_unlock(sk, other);
1165 }
1166 return 0;
1167
1168out_unlock:
1169 unix_state_double_unlock(sk, other);
1170 sock_put(other);
1171out:
1172 return err;
1173}
1174
1175static long unix_wait_for_peer(struct sock *other, long timeo)
1176{
1177 struct unix_sock *u = unix_sk(other);
1178 int sched;
1179 DEFINE_WAIT(wait);
1180
1181 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1182
1183 sched = !sock_flag(other, SOCK_DEAD) &&
1184 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1185 unix_recvq_full(other);
1186
1187 unix_state_unlock(other);
1188
1189 if (sched)
1190 timeo = schedule_timeout(timeo);
1191
1192 finish_wait(&u->peer_wait, &wait);
1193 return timeo;
1194}
1195
1196static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1197 int addr_len, int flags)
1198{
1199 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1200 struct sock *sk = sock->sk;
1201 struct net *net = sock_net(sk);
1202 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1203 struct sock *newsk = NULL;
1204 struct sock *other = NULL;
1205 struct sk_buff *skb = NULL;
1206 unsigned int hash;
1207 int st;
1208 int err;
1209 long timeo;
1210
1211 err = unix_mkname(sunaddr, addr_len, &hash);
1212 if (err < 0)
1213 goto out;
1214 addr_len = err;
1215
1216 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1217 (err = unix_autobind(sock)) != 0)
1218 goto out;
1219
1220 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1221
1222 /* First of all allocate resources.
1223 If we will make it after state is locked,
1224 we will have to recheck all again in any case.
1225 */
1226
1227 err = -ENOMEM;
1228
1229 /* create new sock for complete connection */
1230 newsk = unix_create1(sock_net(sk), NULL, 0);
1231 if (newsk == NULL)
1232 goto out;
1233
1234 /* Allocate skb for sending to listening sock */
1235 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1236 if (skb == NULL)
1237 goto out;
1238
1239restart:
1240 /* Find listening sock. */
1241 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1242 if (!other)
1243 goto out;
1244
1245 /* Latch state of peer */
1246 unix_state_lock(other);
1247
1248 /* Apparently VFS overslept socket death. Retry. */
1249 if (sock_flag(other, SOCK_DEAD)) {
1250 unix_state_unlock(other);
1251 sock_put(other);
1252 goto restart;
1253 }
1254
1255 err = -ECONNREFUSED;
1256 if (other->sk_state != TCP_LISTEN)
1257 goto out_unlock;
1258 if (other->sk_shutdown & RCV_SHUTDOWN)
1259 goto out_unlock;
1260
1261 if (unix_recvq_full(other)) {
1262 err = -EAGAIN;
1263 if (!timeo)
1264 goto out_unlock;
1265
1266 timeo = unix_wait_for_peer(other, timeo);
1267
1268 err = sock_intr_errno(timeo);
1269 if (signal_pending(current))
1270 goto out;
1271 sock_put(other);
1272 goto restart;
1273 }
1274
1275 /* Latch our state.
1276
1277 It is tricky place. We need to grab our state lock and cannot
1278 drop lock on peer. It is dangerous because deadlock is
1279 possible. Connect to self case and simultaneous
1280 attempt to connect are eliminated by checking socket
1281 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1282 check this before attempt to grab lock.
1283
1284 Well, and we have to recheck the state after socket locked.
1285 */
1286 st = sk->sk_state;
1287
1288 switch (st) {
1289 case TCP_CLOSE:
1290 /* This is ok... continue with connect */
1291 break;
1292 case TCP_ESTABLISHED:
1293 /* Socket is already connected */
1294 err = -EISCONN;
1295 goto out_unlock;
1296 default:
1297 err = -EINVAL;
1298 goto out_unlock;
1299 }
1300
1301 unix_state_lock_nested(sk);
1302
1303 if (sk->sk_state != st) {
1304 unix_state_unlock(sk);
1305 unix_state_unlock(other);
1306 sock_put(other);
1307 goto restart;
1308 }
1309
1310 err = security_unix_stream_connect(sk, other, newsk);
1311 if (err) {
1312 unix_state_unlock(sk);
1313 goto out_unlock;
1314 }
1315
1316 /* The way is open! Fastly set all the necessary fields... */
1317
1318 sock_hold(sk);
1319 unix_peer(newsk) = sk;
1320 newsk->sk_state = TCP_ESTABLISHED;
1321 newsk->sk_type = sk->sk_type;
1322 init_peercred(newsk);
1323 newu = unix_sk(newsk);
1324 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1325 otheru = unix_sk(other);
1326
1327 /* copy address information from listening to new sock*/
1328 if (otheru->addr) {
1329 refcount_inc(&otheru->addr->refcnt);
1330 newu->addr = otheru->addr;
1331 }
1332 if (otheru->path.dentry) {
1333 path_get(&otheru->path);
1334 newu->path = otheru->path;
1335 }
1336
1337 /* Set credentials */
1338 copy_peercred(sk, other);
1339
1340 sock->state = SS_CONNECTED;
1341 sk->sk_state = TCP_ESTABLISHED;
1342 sock_hold(newsk);
1343
1344 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1345 unix_peer(sk) = newsk;
1346
1347 unix_state_unlock(sk);
1348
1349 /* take ten and and send info to listening sock */
1350 spin_lock(&other->sk_receive_queue.lock);
1351 __skb_queue_tail(&other->sk_receive_queue, skb);
1352 spin_unlock(&other->sk_receive_queue.lock);
1353 unix_state_unlock(other);
1354 other->sk_data_ready(other);
1355 sock_put(other);
1356 return 0;
1357
1358out_unlock:
1359 if (other)
1360 unix_state_unlock(other);
1361
1362out:
1363 kfree_skb(skb);
1364 if (newsk)
1365 unix_release_sock(newsk, 0);
1366 if (other)
1367 sock_put(other);
1368 return err;
1369}
1370
1371static int unix_socketpair(struct socket *socka, struct socket *sockb)
1372{
1373 struct sock *ska = socka->sk, *skb = sockb->sk;
1374
1375 /* Join our sockets back to back */
1376 sock_hold(ska);
1377 sock_hold(skb);
1378 unix_peer(ska) = skb;
1379 unix_peer(skb) = ska;
1380 init_peercred(ska);
1381 init_peercred(skb);
1382
1383 if (ska->sk_type != SOCK_DGRAM) {
1384 ska->sk_state = TCP_ESTABLISHED;
1385 skb->sk_state = TCP_ESTABLISHED;
1386 socka->state = SS_CONNECTED;
1387 sockb->state = SS_CONNECTED;
1388 }
1389 return 0;
1390}
1391
1392static void unix_sock_inherit_flags(const struct socket *old,
1393 struct socket *new)
1394{
1395 if (test_bit(SOCK_PASSCRED, &old->flags))
1396 set_bit(SOCK_PASSCRED, &new->flags);
1397 if (test_bit(SOCK_PASSSEC, &old->flags))
1398 set_bit(SOCK_PASSSEC, &new->flags);
1399}
1400
1401static int unix_accept(struct socket *sock, struct socket *newsock, int flags,
1402 bool kern)
1403{
1404 struct sock *sk = sock->sk;
1405 struct sock *tsk;
1406 struct sk_buff *skb;
1407 int err;
1408
1409 err = -EOPNOTSUPP;
1410 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1411 goto out;
1412
1413 err = -EINVAL;
1414 if (sk->sk_state != TCP_LISTEN)
1415 goto out;
1416
1417 /* If socket state is TCP_LISTEN it cannot change (for now...),
1418 * so that no locks are necessary.
1419 */
1420
1421 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1422 if (!skb) {
1423 /* This means receive shutdown. */
1424 if (err == 0)
1425 err = -EINVAL;
1426 goto out;
1427 }
1428
1429 tsk = skb->sk;
1430 skb_free_datagram(sk, skb);
1431 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1432
1433 /* attach accepted sock to socket */
1434 unix_state_lock(tsk);
1435 newsock->state = SS_CONNECTED;
1436 unix_sock_inherit_flags(sock, newsock);
1437 sock_graft(tsk, newsock);
1438 unix_state_unlock(tsk);
1439 return 0;
1440
1441out:
1442 return err;
1443}
1444
1445
1446static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1447{
1448 struct sock *sk = sock->sk;
1449 struct unix_sock *u;
1450 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1451 int err = 0;
1452
1453 if (peer) {
1454 sk = unix_peer_get(sk);
1455
1456 err = -ENOTCONN;
1457 if (!sk)
1458 goto out;
1459 err = 0;
1460 } else {
1461 sock_hold(sk);
1462 }
1463
1464 u = unix_sk(sk);
1465 unix_state_lock(sk);
1466 if (!u->addr) {
1467 sunaddr->sun_family = AF_UNIX;
1468 sunaddr->sun_path[0] = 0;
1469 err = sizeof(short);
1470 } else {
1471 struct unix_address *addr = u->addr;
1472
1473 err = addr->len;
1474 memcpy(sunaddr, addr->name, addr->len);
1475 }
1476 unix_state_unlock(sk);
1477 sock_put(sk);
1478out:
1479 return err;
1480}
1481
1482static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1483{
1484 int i;
1485
1486 scm->fp = UNIXCB(skb).fp;
1487 UNIXCB(skb).fp = NULL;
1488
1489 for (i = scm->fp->count-1; i >= 0; i--)
1490 unix_notinflight(scm->fp->user, scm->fp->fp[i]);
1491}
1492
1493static void unix_destruct_scm(struct sk_buff *skb)
1494{
1495 struct scm_cookie scm;
1496 memset(&scm, 0, sizeof(scm));
1497 scm.pid = UNIXCB(skb).pid;
1498 if (UNIXCB(skb).fp)
1499 unix_detach_fds(&scm, skb);
1500
1501 /* Alas, it calls VFS */
1502 /* So fscking what? fput() had been SMP-safe since the last Summer */
1503 scm_destroy(&scm);
1504 sock_wfree(skb);
1505}
1506
1507/*
1508 * The "user->unix_inflight" variable is protected by the garbage
1509 * collection lock, and we just read it locklessly here. If you go
1510 * over the limit, there might be a tiny race in actually noticing
1511 * it across threads. Tough.
1512 */
1513static inline bool too_many_unix_fds(struct task_struct *p)
1514{
1515 struct user_struct *user = current_user();
1516
1517 if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
1518 return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1519 return false;
1520}
1521
1522static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1523{
1524 int i;
1525
1526 if (too_many_unix_fds(current))
1527 return -ETOOMANYREFS;
1528
1529 /*
1530 * Need to duplicate file references for the sake of garbage
1531 * collection. Otherwise a socket in the fps might become a
1532 * candidate for GC while the skb is not yet queued.
1533 */
1534 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1535 if (!UNIXCB(skb).fp)
1536 return -ENOMEM;
1537
1538 for (i = scm->fp->count - 1; i >= 0; i--)
1539 unix_inflight(scm->fp->user, scm->fp->fp[i]);
1540 return 0;
1541}
1542
1543static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1544{
1545 int err = 0;
1546
1547 UNIXCB(skb).pid = get_pid(scm->pid);
1548 UNIXCB(skb).uid = scm->creds.uid;
1549 UNIXCB(skb).gid = scm->creds.gid;
1550 UNIXCB(skb).fp = NULL;
1551 unix_get_secdata(scm, skb);
1552 if (scm->fp && send_fds)
1553 err = unix_attach_fds(scm, skb);
1554
1555 skb->destructor = unix_destruct_scm;
1556 return err;
1557}
1558
1559static bool unix_passcred_enabled(const struct socket *sock,
1560 const struct sock *other)
1561{
1562 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1563 !other->sk_socket ||
1564 test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1565}
1566
1567/*
1568 * Some apps rely on write() giving SCM_CREDENTIALS
1569 * We include credentials if source or destination socket
1570 * asserted SOCK_PASSCRED.
1571 */
1572static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1573 const struct sock *other)
1574{
1575 if (UNIXCB(skb).pid)
1576 return;
1577 if (unix_passcred_enabled(sock, other)) {
1578 UNIXCB(skb).pid = get_pid(task_tgid(current));
1579 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1580 }
1581}
1582
1583static int maybe_init_creds(struct scm_cookie *scm,
1584 struct socket *socket,
1585 const struct sock *other)
1586{
1587 int err;
1588 struct msghdr msg = { .msg_controllen = 0 };
1589
1590 err = scm_send(socket, &msg, scm, false);
1591 if (err)
1592 return err;
1593
1594 if (unix_passcred_enabled(socket, other)) {
1595 scm->pid = get_pid(task_tgid(current));
1596 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1597 }
1598 return err;
1599}
1600
1601static bool unix_skb_scm_eq(struct sk_buff *skb,
1602 struct scm_cookie *scm)
1603{
1604 const struct unix_skb_parms *u = &UNIXCB(skb);
1605
1606 return u->pid == scm->pid &&
1607 uid_eq(u->uid, scm->creds.uid) &&
1608 gid_eq(u->gid, scm->creds.gid) &&
1609 unix_secdata_eq(scm, skb);
1610}
1611
1612/*
1613 * Send AF_UNIX data.
1614 */
1615
1616static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1617 size_t len)
1618{
1619 struct sock *sk = sock->sk;
1620 struct net *net = sock_net(sk);
1621 struct unix_sock *u = unix_sk(sk);
1622 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1623 struct sock *other = NULL;
1624 int namelen = 0; /* fake GCC */
1625 int err;
1626 unsigned int hash;
1627 struct sk_buff *skb;
1628 long timeo;
1629 struct scm_cookie scm;
1630 int data_len = 0;
1631 int sk_locked;
1632
1633 wait_for_unix_gc();
1634 err = scm_send(sock, msg, &scm, false);
1635 if (err < 0)
1636 return err;
1637
1638 err = -EOPNOTSUPP;
1639 if (msg->msg_flags&MSG_OOB)
1640 goto out;
1641
1642 if (msg->msg_namelen) {
1643 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1644 if (err < 0)
1645 goto out;
1646 namelen = err;
1647 } else {
1648 sunaddr = NULL;
1649 err = -ENOTCONN;
1650 other = unix_peer_get(sk);
1651 if (!other)
1652 goto out;
1653 }
1654
1655 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1656 && (err = unix_autobind(sock)) != 0)
1657 goto out;
1658
1659 err = -EMSGSIZE;
1660 if (len > sk->sk_sndbuf - 32)
1661 goto out;
1662
1663 if (len > SKB_MAX_ALLOC) {
1664 data_len = min_t(size_t,
1665 len - SKB_MAX_ALLOC,
1666 MAX_SKB_FRAGS * PAGE_SIZE);
1667 data_len = PAGE_ALIGN(data_len);
1668
1669 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1670 }
1671
1672 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1673 msg->msg_flags & MSG_DONTWAIT, &err,
1674 PAGE_ALLOC_COSTLY_ORDER);
1675 if (skb == NULL)
1676 goto out;
1677
1678 err = unix_scm_to_skb(&scm, skb, true);
1679 if (err < 0)
1680 goto out_free;
1681
1682 skb_put(skb, len - data_len);
1683 skb->data_len = data_len;
1684 skb->len = len;
1685 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1686 if (err)
1687 goto out_free;
1688
1689 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1690
1691restart:
1692 if (!other) {
1693 err = -ECONNRESET;
1694 if (sunaddr == NULL)
1695 goto out_free;
1696
1697 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1698 hash, &err);
1699 if (other == NULL)
1700 goto out_free;
1701 }
1702
1703 if (sk_filter(other, skb) < 0) {
1704 /* Toss the packet but do not return any error to the sender */
1705 err = len;
1706 goto out_free;
1707 }
1708
1709 sk_locked = 0;
1710 unix_state_lock(other);
1711restart_locked:
1712 err = -EPERM;
1713 if (!unix_may_send(sk, other))
1714 goto out_unlock;
1715
1716 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1717 /*
1718 * Check with 1003.1g - what should
1719 * datagram error
1720 */
1721 unix_state_unlock(other);
1722 sock_put(other);
1723
1724 if (!sk_locked)
1725 unix_state_lock(sk);
1726
1727 err = 0;
1728 if (unix_peer(sk) == other) {
1729 unix_peer(sk) = NULL;
1730 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1731
1732 unix_state_unlock(sk);
1733
1734 unix_dgram_disconnected(sk, other);
1735 sock_put(other);
1736 err = -ECONNREFUSED;
1737 } else {
1738 unix_state_unlock(sk);
1739 }
1740
1741 other = NULL;
1742 if (err)
1743 goto out_free;
1744 goto restart;
1745 }
1746
1747 err = -EPIPE;
1748 if (other->sk_shutdown & RCV_SHUTDOWN)
1749 goto out_unlock;
1750
1751 if (sk->sk_type != SOCK_SEQPACKET) {
1752 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1753 if (err)
1754 goto out_unlock;
1755 }
1756
1757 /* other == sk && unix_peer(other) != sk if
1758 * - unix_peer(sk) == NULL, destination address bound to sk
1759 * - unix_peer(sk) == sk by time of get but disconnected before lock
1760 */
1761 if (other != sk &&
1762 unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1763 if (timeo) {
1764 timeo = unix_wait_for_peer(other, timeo);
1765
1766 err = sock_intr_errno(timeo);
1767 if (signal_pending(current))
1768 goto out_free;
1769
1770 goto restart;
1771 }
1772
1773 if (!sk_locked) {
1774 unix_state_unlock(other);
1775 unix_state_double_lock(sk, other);
1776 }
1777
1778 if (unix_peer(sk) != other ||
1779 unix_dgram_peer_wake_me(sk, other)) {
1780 err = -EAGAIN;
1781 sk_locked = 1;
1782 goto out_unlock;
1783 }
1784
1785 if (!sk_locked) {
1786 sk_locked = 1;
1787 goto restart_locked;
1788 }
1789 }
1790
1791 if (unlikely(sk_locked))
1792 unix_state_unlock(sk);
1793
1794 if (sock_flag(other, SOCK_RCVTSTAMP))
1795 __net_timestamp(skb);
1796 maybe_add_creds(skb, sock, other);
1797 skb_queue_tail(&other->sk_receive_queue, skb);
1798 unix_state_unlock(other);
1799 other->sk_data_ready(other);
1800 sock_put(other);
1801 scm_destroy(&scm);
1802 return len;
1803
1804out_unlock:
1805 if (sk_locked)
1806 unix_state_unlock(sk);
1807 unix_state_unlock(other);
1808out_free:
1809 kfree_skb(skb);
1810out:
1811 if (other)
1812 sock_put(other);
1813 scm_destroy(&scm);
1814 return err;
1815}
1816
1817/* We use paged skbs for stream sockets, and limit occupancy to 32768
1818 * bytes, and a minimum of a full page.
1819 */
1820#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1821
1822static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
1823 size_t len)
1824{
1825 struct sock *sk = sock->sk;
1826 struct sock *other = NULL;
1827 int err, size;
1828 struct sk_buff *skb;
1829 int sent = 0;
1830 struct scm_cookie scm;
1831 bool fds_sent = false;
1832 int data_len;
1833
1834 wait_for_unix_gc();
1835 err = scm_send(sock, msg, &scm, false);
1836 if (err < 0)
1837 return err;
1838
1839 err = -EOPNOTSUPP;
1840 if (msg->msg_flags&MSG_OOB)
1841 goto out_err;
1842
1843 if (msg->msg_namelen) {
1844 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1845 goto out_err;
1846 } else {
1847 err = -ENOTCONN;
1848 other = unix_peer(sk);
1849 if (!other)
1850 goto out_err;
1851 }
1852
1853 if (sk->sk_shutdown & SEND_SHUTDOWN)
1854 goto pipe_err;
1855
1856 while (sent < len) {
1857 size = len - sent;
1858
1859 /* Keep two messages in the pipe so it schedules better */
1860 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1861
1862 /* allow fallback to order-0 allocations */
1863 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1864
1865 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1866
1867 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
1868
1869 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1870 msg->msg_flags & MSG_DONTWAIT, &err,
1871 get_order(UNIX_SKB_FRAGS_SZ));
1872 if (!skb)
1873 goto out_err;
1874
1875 /* Only send the fds in the first buffer */
1876 err = unix_scm_to_skb(&scm, skb, !fds_sent);
1877 if (err < 0) {
1878 kfree_skb(skb);
1879 goto out_err;
1880 }
1881 fds_sent = true;
1882
1883 skb_put(skb, size - data_len);
1884 skb->data_len = data_len;
1885 skb->len = size;
1886 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
1887 if (err) {
1888 kfree_skb(skb);
1889 goto out_err;
1890 }
1891
1892 unix_state_lock(other);
1893
1894 if (sock_flag(other, SOCK_DEAD) ||
1895 (other->sk_shutdown & RCV_SHUTDOWN))
1896 goto pipe_err_free;
1897
1898 maybe_add_creds(skb, sock, other);
1899 skb_queue_tail(&other->sk_receive_queue, skb);
1900 unix_state_unlock(other);
1901 other->sk_data_ready(other);
1902 sent += size;
1903 }
1904
1905 scm_destroy(&scm);
1906
1907 return sent;
1908
1909pipe_err_free:
1910 unix_state_unlock(other);
1911 kfree_skb(skb);
1912pipe_err:
1913 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1914 send_sig(SIGPIPE, current, 0);
1915 err = -EPIPE;
1916out_err:
1917 scm_destroy(&scm);
1918 return sent ? : err;
1919}
1920
1921static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
1922 int offset, size_t size, int flags)
1923{
1924 int err;
1925 bool send_sigpipe = false;
1926 bool init_scm = true;
1927 struct scm_cookie scm;
1928 struct sock *other, *sk = socket->sk;
1929 struct sk_buff *skb, *newskb = NULL, *tail = NULL;
1930
1931 if (flags & MSG_OOB)
1932 return -EOPNOTSUPP;
1933
1934 other = unix_peer(sk);
1935 if (!other || sk->sk_state != TCP_ESTABLISHED)
1936 return -ENOTCONN;
1937
1938 if (false) {
1939alloc_skb:
1940 unix_state_unlock(other);
1941 mutex_unlock(&unix_sk(other)->iolock);
1942 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
1943 &err, 0);
1944 if (!newskb)
1945 goto err;
1946 }
1947
1948 /* we must acquire iolock as we modify already present
1949 * skbs in the sk_receive_queue and mess with skb->len
1950 */
1951 err = mutex_lock_interruptible(&unix_sk(other)->iolock);
1952 if (err) {
1953 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
1954 goto err;
1955 }
1956
1957 if (sk->sk_shutdown & SEND_SHUTDOWN) {
1958 err = -EPIPE;
1959 send_sigpipe = true;
1960 goto err_unlock;
1961 }
1962
1963 unix_state_lock(other);
1964
1965 if (sock_flag(other, SOCK_DEAD) ||
1966 other->sk_shutdown & RCV_SHUTDOWN) {
1967 err = -EPIPE;
1968 send_sigpipe = true;
1969 goto err_state_unlock;
1970 }
1971
1972 if (init_scm) {
1973 err = maybe_init_creds(&scm, socket, other);
1974 if (err)
1975 goto err_state_unlock;
1976 init_scm = false;
1977 }
1978
1979 skb = skb_peek_tail(&other->sk_receive_queue);
1980 if (tail && tail == skb) {
1981 skb = newskb;
1982 } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
1983 if (newskb) {
1984 skb = newskb;
1985 } else {
1986 tail = skb;
1987 goto alloc_skb;
1988 }
1989 } else if (newskb) {
1990 /* this is fast path, we don't necessarily need to
1991 * call to kfree_skb even though with newskb == NULL
1992 * this - does no harm
1993 */
1994 consume_skb(newskb);
1995 newskb = NULL;
1996 }
1997
1998 if (skb_append_pagefrags(skb, page, offset, size)) {
1999 tail = skb;
2000 goto alloc_skb;
2001 }
2002
2003 skb->len += size;
2004 skb->data_len += size;
2005 skb->truesize += size;
2006 refcount_add(size, &sk->sk_wmem_alloc);
2007
2008 if (newskb) {
2009 err = unix_scm_to_skb(&scm, skb, false);
2010 if (err)
2011 goto err_state_unlock;
2012 spin_lock(&other->sk_receive_queue.lock);
2013 __skb_queue_tail(&other->sk_receive_queue, newskb);
2014 spin_unlock(&other->sk_receive_queue.lock);
2015 }
2016
2017 unix_state_unlock(other);
2018 mutex_unlock(&unix_sk(other)->iolock);
2019
2020 other->sk_data_ready(other);
2021 scm_destroy(&scm);
2022 return size;
2023
2024err_state_unlock:
2025 unix_state_unlock(other);
2026err_unlock:
2027 mutex_unlock(&unix_sk(other)->iolock);
2028err:
2029 kfree_skb(newskb);
2030 if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2031 send_sig(SIGPIPE, current, 0);
2032 if (!init_scm)
2033 scm_destroy(&scm);
2034 return err;
2035}
2036
2037static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2038 size_t len)
2039{
2040 int err;
2041 struct sock *sk = sock->sk;
2042
2043 err = sock_error(sk);
2044 if (err)
2045 return err;
2046
2047 if (sk->sk_state != TCP_ESTABLISHED)
2048 return -ENOTCONN;
2049
2050 if (msg->msg_namelen)
2051 msg->msg_namelen = 0;
2052
2053 return unix_dgram_sendmsg(sock, msg, len);
2054}
2055
2056static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2057 size_t size, int flags)
2058{
2059 struct sock *sk = sock->sk;
2060
2061 if (sk->sk_state != TCP_ESTABLISHED)
2062 return -ENOTCONN;
2063
2064 return unix_dgram_recvmsg(sock, msg, size, flags);
2065}
2066
2067static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2068{
2069 struct unix_sock *u = unix_sk(sk);
2070
2071 if (u->addr) {
2072 msg->msg_namelen = u->addr->len;
2073 memcpy(msg->msg_name, u->addr->name, u->addr->len);
2074 }
2075}
2076
2077static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
2078 size_t size, int flags)
2079{
2080 struct scm_cookie scm;
2081 struct sock *sk = sock->sk;
2082 struct unix_sock *u = unix_sk(sk);
2083 struct sk_buff *skb, *last;
2084 long timeo;
2085 int err;
2086 int peeked, skip;
2087
2088 err = -EOPNOTSUPP;
2089 if (flags&MSG_OOB)
2090 goto out;
2091
2092 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2093
2094 do {
2095 mutex_lock(&u->iolock);
2096
2097 skip = sk_peek_offset(sk, flags);
2098 skb = __skb_try_recv_datagram(sk, flags, NULL, &peeked, &skip,
2099 &err, &last);
2100 if (skb)
2101 break;
2102
2103 mutex_unlock(&u->iolock);
2104
2105 if (err != -EAGAIN)
2106 break;
2107 } while (timeo &&
2108 !__skb_wait_for_more_packets(sk, &err, &timeo, last));
2109
2110 if (!skb) { /* implies iolock unlocked */
2111 unix_state_lock(sk);
2112 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2113 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2114 (sk->sk_shutdown & RCV_SHUTDOWN))
2115 err = 0;
2116 unix_state_unlock(sk);
2117 goto out;
2118 }
2119
2120 if (wq_has_sleeper(&u->peer_wait))
2121 wake_up_interruptible_sync_poll(&u->peer_wait,
2122 EPOLLOUT | EPOLLWRNORM |
2123 EPOLLWRBAND);
2124
2125 if (msg->msg_name)
2126 unix_copy_addr(msg, skb->sk);
2127
2128 if (size > skb->len - skip)
2129 size = skb->len - skip;
2130 else if (size < skb->len - skip)
2131 msg->msg_flags |= MSG_TRUNC;
2132
2133 err = skb_copy_datagram_msg(skb, skip, msg, size);
2134 if (err)
2135 goto out_free;
2136
2137 if (sock_flag(sk, SOCK_RCVTSTAMP))
2138 __sock_recv_timestamp(msg, sk, skb);
2139
2140 memset(&scm, 0, sizeof(scm));
2141
2142 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2143 unix_set_secdata(&scm, skb);
2144
2145 if (!(flags & MSG_PEEK)) {
2146 if (UNIXCB(skb).fp)
2147 unix_detach_fds(&scm, skb);
2148
2149 sk_peek_offset_bwd(sk, skb->len);
2150 } else {
2151 /* It is questionable: on PEEK we could:
2152 - do not return fds - good, but too simple 8)
2153 - return fds, and do not return them on read (old strategy,
2154 apparently wrong)
2155 - clone fds (I chose it for now, it is the most universal
2156 solution)
2157
2158 POSIX 1003.1g does not actually define this clearly
2159 at all. POSIX 1003.1g doesn't define a lot of things
2160 clearly however!
2161
2162 */
2163
2164 sk_peek_offset_fwd(sk, size);
2165
2166 if (UNIXCB(skb).fp)
2167 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2168 }
2169 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2170
2171 scm_recv(sock, msg, &scm, flags);
2172
2173out_free:
2174 skb_free_datagram(sk, skb);
2175 mutex_unlock(&u->iolock);
2176out:
2177 return err;
2178}
2179
2180/*
2181 * Sleep until more data has arrived. But check for races..
2182 */
2183static long unix_stream_data_wait(struct sock *sk, long timeo,
2184 struct sk_buff *last, unsigned int last_len,
2185 bool freezable)
2186{
2187 struct sk_buff *tail;
2188 DEFINE_WAIT(wait);
2189
2190 unix_state_lock(sk);
2191
2192 for (;;) {
2193 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2194
2195 tail = skb_peek_tail(&sk->sk_receive_queue);
2196 if (tail != last ||
2197 (tail && tail->len != last_len) ||
2198 sk->sk_err ||
2199 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2200 signal_pending(current) ||
2201 !timeo)
2202 break;
2203
2204 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2205 unix_state_unlock(sk);
2206 if (freezable)
2207 timeo = freezable_schedule_timeout(timeo);
2208 else
2209 timeo = schedule_timeout(timeo);
2210 unix_state_lock(sk);
2211
2212 if (sock_flag(sk, SOCK_DEAD))
2213 break;
2214
2215 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2216 }
2217
2218 finish_wait(sk_sleep(sk), &wait);
2219 unix_state_unlock(sk);
2220 return timeo;
2221}
2222
2223static unsigned int unix_skb_len(const struct sk_buff *skb)
2224{
2225 return skb->len - UNIXCB(skb).consumed;
2226}
2227
2228struct unix_stream_read_state {
2229 int (*recv_actor)(struct sk_buff *, int, int,
2230 struct unix_stream_read_state *);
2231 struct socket *socket;
2232 struct msghdr *msg;
2233 struct pipe_inode_info *pipe;
2234 size_t size;
2235 int flags;
2236 unsigned int splice_flags;
2237};
2238
2239static int unix_stream_read_generic(struct unix_stream_read_state *state,
2240 bool freezable)
2241{
2242 struct scm_cookie scm;
2243 struct socket *sock = state->socket;
2244 struct sock *sk = sock->sk;
2245 struct unix_sock *u = unix_sk(sk);
2246 int copied = 0;
2247 int flags = state->flags;
2248 int noblock = flags & MSG_DONTWAIT;
2249 bool check_creds = false;
2250 int target;
2251 int err = 0;
2252 long timeo;
2253 int skip;
2254 size_t size = state->size;
2255 unsigned int last_len;
2256
2257 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2258 err = -EINVAL;
2259 goto out;
2260 }
2261
2262 if (unlikely(flags & MSG_OOB)) {
2263 err = -EOPNOTSUPP;
2264 goto out;
2265 }
2266
2267 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2268 timeo = sock_rcvtimeo(sk, noblock);
2269
2270 memset(&scm, 0, sizeof(scm));
2271
2272 /* Lock the socket to prevent queue disordering
2273 * while sleeps in memcpy_tomsg
2274 */
2275 mutex_lock(&u->iolock);
2276
2277 skip = max(sk_peek_offset(sk, flags), 0);
2278
2279 do {
2280 int chunk;
2281 bool drop_skb;
2282 struct sk_buff *skb, *last;
2283
2284redo:
2285 unix_state_lock(sk);
2286 if (sock_flag(sk, SOCK_DEAD)) {
2287 err = -ECONNRESET;
2288 goto unlock;
2289 }
2290 last = skb = skb_peek(&sk->sk_receive_queue);
2291 last_len = last ? last->len : 0;
2292again:
2293 if (skb == NULL) {
2294 if (copied >= target)
2295 goto unlock;
2296
2297 /*
2298 * POSIX 1003.1g mandates this order.
2299 */
2300
2301 err = sock_error(sk);
2302 if (err)
2303 goto unlock;
2304 if (sk->sk_shutdown & RCV_SHUTDOWN)
2305 goto unlock;
2306
2307 unix_state_unlock(sk);
2308 if (!timeo) {
2309 err = -EAGAIN;
2310 break;
2311 }
2312
2313 mutex_unlock(&u->iolock);
2314
2315 timeo = unix_stream_data_wait(sk, timeo, last,
2316 last_len, freezable);
2317
2318 if (signal_pending(current)) {
2319 err = sock_intr_errno(timeo);
2320 scm_destroy(&scm);
2321 goto out;
2322 }
2323
2324 mutex_lock(&u->iolock);
2325 goto redo;
2326unlock:
2327 unix_state_unlock(sk);
2328 break;
2329 }
2330
2331 while (skip >= unix_skb_len(skb)) {
2332 skip -= unix_skb_len(skb);
2333 last = skb;
2334 last_len = skb->len;
2335 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2336 if (!skb)
2337 goto again;
2338 }
2339
2340 unix_state_unlock(sk);
2341
2342 if (check_creds) {
2343 /* Never glue messages from different writers */
2344 if (!unix_skb_scm_eq(skb, &scm))
2345 break;
2346 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2347 /* Copy credentials */
2348 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2349 unix_set_secdata(&scm, skb);
2350 check_creds = true;
2351 }
2352
2353 /* Copy address just once */
2354 if (state->msg && state->msg->msg_name) {
2355 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2356 state->msg->msg_name);
2357 unix_copy_addr(state->msg, skb->sk);
2358 sunaddr = NULL;
2359 }
2360
2361 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2362 skb_get(skb);
2363 chunk = state->recv_actor(skb, skip, chunk, state);
2364 drop_skb = !unix_skb_len(skb);
2365 /* skb is only safe to use if !drop_skb */
2366 consume_skb(skb);
2367 if (chunk < 0) {
2368 if (copied == 0)
2369 copied = -EFAULT;
2370 break;
2371 }
2372 copied += chunk;
2373 size -= chunk;
2374
2375 if (drop_skb) {
2376 /* the skb was touched by a concurrent reader;
2377 * we should not expect anything from this skb
2378 * anymore and assume it invalid - we can be
2379 * sure it was dropped from the socket queue
2380 *
2381 * let's report a short read
2382 */
2383 err = 0;
2384 break;
2385 }
2386
2387 /* Mark read part of skb as used */
2388 if (!(flags & MSG_PEEK)) {
2389 UNIXCB(skb).consumed += chunk;
2390
2391 sk_peek_offset_bwd(sk, chunk);
2392
2393 if (UNIXCB(skb).fp)
2394 unix_detach_fds(&scm, skb);
2395
2396 if (unix_skb_len(skb))
2397 break;
2398
2399 skb_unlink(skb, &sk->sk_receive_queue);
2400 consume_skb(skb);
2401
2402 if (scm.fp)
2403 break;
2404 } else {
2405 /* It is questionable, see note in unix_dgram_recvmsg.
2406 */
2407 if (UNIXCB(skb).fp)
2408 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2409
2410 sk_peek_offset_fwd(sk, chunk);
2411
2412 if (UNIXCB(skb).fp)
2413 break;
2414
2415 skip = 0;
2416 last = skb;
2417 last_len = skb->len;
2418 unix_state_lock(sk);
2419 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2420 if (skb)
2421 goto again;
2422 unix_state_unlock(sk);
2423 break;
2424 }
2425 } while (size);
2426
2427 mutex_unlock(&u->iolock);
2428 if (state->msg)
2429 scm_recv(sock, state->msg, &scm, flags);
2430 else
2431 scm_destroy(&scm);
2432out:
2433 return copied ? : err;
2434}
2435
2436static int unix_stream_read_actor(struct sk_buff *skb,
2437 int skip, int chunk,
2438 struct unix_stream_read_state *state)
2439{
2440 int ret;
2441
2442 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2443 state->msg, chunk);
2444 return ret ?: chunk;
2445}
2446
2447static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2448 size_t size, int flags)
2449{
2450 struct unix_stream_read_state state = {
2451 .recv_actor = unix_stream_read_actor,
2452 .socket = sock,
2453 .msg = msg,
2454 .size = size,
2455 .flags = flags
2456 };
2457
2458 return unix_stream_read_generic(&state, true);
2459}
2460
2461static int unix_stream_splice_actor(struct sk_buff *skb,
2462 int skip, int chunk,
2463 struct unix_stream_read_state *state)
2464{
2465 return skb_splice_bits(skb, state->socket->sk,
2466 UNIXCB(skb).consumed + skip,
2467 state->pipe, chunk, state->splice_flags);
2468}
2469
2470static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2471 struct pipe_inode_info *pipe,
2472 size_t size, unsigned int flags)
2473{
2474 struct unix_stream_read_state state = {
2475 .recv_actor = unix_stream_splice_actor,
2476 .socket = sock,
2477 .pipe = pipe,
2478 .size = size,
2479 .splice_flags = flags,
2480 };
2481
2482 if (unlikely(*ppos))
2483 return -ESPIPE;
2484
2485 if (sock->file->f_flags & O_NONBLOCK ||
2486 flags & SPLICE_F_NONBLOCK)
2487 state.flags = MSG_DONTWAIT;
2488
2489 return unix_stream_read_generic(&state, false);
2490}
2491
2492static int unix_shutdown(struct socket *sock, int mode)
2493{
2494 struct sock *sk = sock->sk;
2495 struct sock *other;
2496
2497 if (mode < SHUT_RD || mode > SHUT_RDWR)
2498 return -EINVAL;
2499 /* This maps:
2500 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2501 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2502 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2503 */
2504 ++mode;
2505
2506 unix_state_lock(sk);
2507 sk->sk_shutdown |= mode;
2508 other = unix_peer(sk);
2509 if (other)
2510 sock_hold(other);
2511 unix_state_unlock(sk);
2512 sk->sk_state_change(sk);
2513
2514 if (other &&
2515 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2516
2517 int peer_mode = 0;
2518
2519 if (mode&RCV_SHUTDOWN)
2520 peer_mode |= SEND_SHUTDOWN;
2521 if (mode&SEND_SHUTDOWN)
2522 peer_mode |= RCV_SHUTDOWN;
2523 unix_state_lock(other);
2524 other->sk_shutdown |= peer_mode;
2525 unix_state_unlock(other);
2526 other->sk_state_change(other);
2527 if (peer_mode == SHUTDOWN_MASK)
2528 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2529 else if (peer_mode & RCV_SHUTDOWN)
2530 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2531 }
2532 if (other)
2533 sock_put(other);
2534
2535 return 0;
2536}
2537
2538long unix_inq_len(struct sock *sk)
2539{
2540 struct sk_buff *skb;
2541 long amount = 0;
2542
2543 if (sk->sk_state == TCP_LISTEN)
2544 return -EINVAL;
2545
2546 spin_lock(&sk->sk_receive_queue.lock);
2547 if (sk->sk_type == SOCK_STREAM ||
2548 sk->sk_type == SOCK_SEQPACKET) {
2549 skb_queue_walk(&sk->sk_receive_queue, skb)
2550 amount += unix_skb_len(skb);
2551 } else {
2552 skb = skb_peek(&sk->sk_receive_queue);
2553 if (skb)
2554 amount = skb->len;
2555 }
2556 spin_unlock(&sk->sk_receive_queue.lock);
2557
2558 return amount;
2559}
2560EXPORT_SYMBOL_GPL(unix_inq_len);
2561
2562long unix_outq_len(struct sock *sk)
2563{
2564 return sk_wmem_alloc_get(sk);
2565}
2566EXPORT_SYMBOL_GPL(unix_outq_len);
2567
2568static int unix_open_file(struct sock *sk)
2569{
2570 struct path path;
2571 struct file *f;
2572 int fd;
2573
2574 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
2575 return -EPERM;
2576
2577 unix_state_lock(sk);
2578 path = unix_sk(sk)->path;
2579 if (!path.dentry) {
2580 unix_state_unlock(sk);
2581 return -ENOENT;
2582 }
2583
2584 path_get(&path);
2585 unix_state_unlock(sk);
2586
2587 fd = get_unused_fd_flags(O_CLOEXEC);
2588 if (fd < 0)
2589 goto out;
2590
2591 f = dentry_open(&path, O_PATH, current_cred());
2592 if (IS_ERR(f)) {
2593 put_unused_fd(fd);
2594 fd = PTR_ERR(f);
2595 goto out;
2596 }
2597
2598 fd_install(fd, f);
2599out:
2600 path_put(&path);
2601
2602 return fd;
2603}
2604
2605static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2606{
2607 struct sock *sk = sock->sk;
2608 long amount = 0;
2609 int err;
2610
2611 switch (cmd) {
2612 case SIOCOUTQ:
2613 amount = unix_outq_len(sk);
2614 err = put_user(amount, (int __user *)arg);
2615 break;
2616 case SIOCINQ:
2617 amount = unix_inq_len(sk);
2618 if (amount < 0)
2619 err = amount;
2620 else
2621 err = put_user(amount, (int __user *)arg);
2622 break;
2623 case SIOCUNIXFILE:
2624 err = unix_open_file(sk);
2625 break;
2626 default:
2627 err = -ENOIOCTLCMD;
2628 break;
2629 }
2630 return err;
2631}
2632
2633static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2634{
2635 struct sock *sk = sock->sk;
2636 __poll_t mask;
2637
2638 sock_poll_wait(file, sk_sleep(sk), wait);
2639 mask = 0;
2640
2641 /* exceptional events? */
2642 if (sk->sk_err)
2643 mask |= EPOLLERR;
2644 if (sk->sk_shutdown == SHUTDOWN_MASK)
2645 mask |= EPOLLHUP;
2646 if (sk->sk_shutdown & RCV_SHUTDOWN)
2647 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2648
2649 /* readable? */
2650 if (!skb_queue_empty(&sk->sk_receive_queue))
2651 mask |= EPOLLIN | EPOLLRDNORM;
2652
2653 /* Connection-based need to check for termination and startup */
2654 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2655 sk->sk_state == TCP_CLOSE)
2656 mask |= EPOLLHUP;
2657
2658 /*
2659 * we set writable also when the other side has shut down the
2660 * connection. This prevents stuck sockets.
2661 */
2662 if (unix_writable(sk))
2663 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
2664
2665 return mask;
2666}
2667
2668static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
2669 poll_table *wait)
2670{
2671 struct sock *sk = sock->sk, *other;
2672 unsigned int writable;
2673 __poll_t mask;
2674
2675 sock_poll_wait(file, sk_sleep(sk), wait);
2676 mask = 0;
2677
2678 /* exceptional events? */
2679 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2680 mask |= EPOLLERR |
2681 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
2682
2683 if (sk->sk_shutdown & RCV_SHUTDOWN)
2684 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
2685 if (sk->sk_shutdown == SHUTDOWN_MASK)
2686 mask |= EPOLLHUP;
2687
2688 /* readable? */
2689 if (!skb_queue_empty(&sk->sk_receive_queue))
2690 mask |= EPOLLIN | EPOLLRDNORM;
2691
2692 /* Connection-based need to check for termination and startup */
2693 if (sk->sk_type == SOCK_SEQPACKET) {
2694 if (sk->sk_state == TCP_CLOSE)
2695 mask |= EPOLLHUP;
2696 /* connection hasn't started yet? */
2697 if (sk->sk_state == TCP_SYN_SENT)
2698 return mask;
2699 }
2700
2701 /* No write status requested, avoid expensive OUT tests. */
2702 if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT)))
2703 return mask;
2704
2705 writable = unix_writable(sk);
2706 if (writable) {
2707 unix_state_lock(sk);
2708
2709 other = unix_peer(sk);
2710 if (other && unix_peer(other) != sk &&
2711 unix_recvq_full(other) &&
2712 unix_dgram_peer_wake_me(sk, other))
2713 writable = 0;
2714
2715 unix_state_unlock(sk);
2716 }
2717
2718 if (writable)
2719 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
2720 else
2721 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2722
2723 return mask;
2724}
2725
2726#ifdef CONFIG_PROC_FS
2727
2728#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2729
2730#define get_bucket(x) ((x) >> BUCKET_SPACE)
2731#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2732#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2733
2734static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2735{
2736 unsigned long offset = get_offset(*pos);
2737 unsigned long bucket = get_bucket(*pos);
2738 struct sock *sk;
2739 unsigned long count = 0;
2740
2741 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2742 if (sock_net(sk) != seq_file_net(seq))
2743 continue;
2744 if (++count == offset)
2745 break;
2746 }
2747
2748 return sk;
2749}
2750
2751static struct sock *unix_next_socket(struct seq_file *seq,
2752 struct sock *sk,
2753 loff_t *pos)
2754{
2755 unsigned long bucket;
2756
2757 while (sk > (struct sock *)SEQ_START_TOKEN) {
2758 sk = sk_next(sk);
2759 if (!sk)
2760 goto next_bucket;
2761 if (sock_net(sk) == seq_file_net(seq))
2762 return sk;
2763 }
2764
2765 do {
2766 sk = unix_from_bucket(seq, pos);
2767 if (sk)
2768 return sk;
2769
2770next_bucket:
2771 bucket = get_bucket(*pos) + 1;
2772 *pos = set_bucket_offset(bucket, 1);
2773 } while (bucket < ARRAY_SIZE(unix_socket_table));
2774
2775 return NULL;
2776}
2777
2778static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2779 __acquires(unix_table_lock)
2780{
2781 spin_lock(&unix_table_lock);
2782
2783 if (!*pos)
2784 return SEQ_START_TOKEN;
2785
2786 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2787 return NULL;
2788
2789 return unix_next_socket(seq, NULL, pos);
2790}
2791
2792static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2793{
2794 ++*pos;
2795 return unix_next_socket(seq, v, pos);
2796}
2797
2798static void unix_seq_stop(struct seq_file *seq, void *v)
2799 __releases(unix_table_lock)
2800{
2801 spin_unlock(&unix_table_lock);
2802}
2803
2804static int unix_seq_show(struct seq_file *seq, void *v)
2805{
2806
2807 if (v == SEQ_START_TOKEN)
2808 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2809 "Inode Path\n");
2810 else {
2811 struct sock *s = v;
2812 struct unix_sock *u = unix_sk(s);
2813 unix_state_lock(s);
2814
2815 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2816 s,
2817 refcount_read(&s->sk_refcnt),
2818 0,
2819 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2820 s->sk_type,
2821 s->sk_socket ?
2822 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2823 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2824 sock_i_ino(s));
2825
2826 if (u->addr) {
2827 int i, len;
2828 seq_putc(seq, ' ');
2829
2830 i = 0;
2831 len = u->addr->len - sizeof(short);
2832 if (!UNIX_ABSTRACT(s))
2833 len--;
2834 else {
2835 seq_putc(seq, '@');
2836 i++;
2837 }
2838 for ( ; i < len; i++)
2839 seq_putc(seq, u->addr->name->sun_path[i] ?:
2840 '@');
2841 }
2842 unix_state_unlock(s);
2843 seq_putc(seq, '\n');
2844 }
2845
2846 return 0;
2847}
2848
2849static const struct seq_operations unix_seq_ops = {
2850 .start = unix_seq_start,
2851 .next = unix_seq_next,
2852 .stop = unix_seq_stop,
2853 .show = unix_seq_show,
2854};
2855
2856static int unix_seq_open(struct inode *inode, struct file *file)
2857{
2858 return seq_open_net(inode, file, &unix_seq_ops,
2859 sizeof(struct seq_net_private));
2860}
2861
2862static const struct file_operations unix_seq_fops = {
2863 .open = unix_seq_open,
2864 .read = seq_read,
2865 .llseek = seq_lseek,
2866 .release = seq_release_net,
2867};
2868
2869#endif
2870
2871static const struct net_proto_family unix_family_ops = {
2872 .family = PF_UNIX,
2873 .create = unix_create,
2874 .owner = THIS_MODULE,
2875};
2876
2877
2878static int __net_init unix_net_init(struct net *net)
2879{
2880 int error = -ENOMEM;
2881
2882 net->unx.sysctl_max_dgram_qlen = 10;
2883 if (unix_sysctl_register(net))
2884 goto out;
2885
2886#ifdef CONFIG_PROC_FS
2887 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2888 unix_sysctl_unregister(net);
2889 goto out;
2890 }
2891#endif
2892 error = 0;
2893out:
2894 return error;
2895}
2896
2897static void __net_exit unix_net_exit(struct net *net)
2898{
2899 unix_sysctl_unregister(net);
2900 remove_proc_entry("unix", net->proc_net);
2901}
2902
2903static struct pernet_operations unix_net_ops = {
2904 .init = unix_net_init,
2905 .exit = unix_net_exit,
2906};
2907
2908static int __init af_unix_init(void)
2909{
2910 int rc = -1;
2911
2912 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2913
2914 rc = proto_register(&unix_proto, 1);
2915 if (rc != 0) {
2916 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
2917 goto out;
2918 }
2919
2920 sock_register(&unix_family_ops);
2921 register_pernet_subsys(&unix_net_ops);
2922out:
2923 return rc;
2924}
2925
2926static void __exit af_unix_exit(void)
2927{
2928 sock_unregister(PF_UNIX);
2929 proto_unregister(&unix_proto);
2930 unregister_pernet_subsys(&unix_net_ops);
2931}
2932
2933/* Earlier than device_initcall() so that other drivers invoking
2934 request_module() don't end up in a loop when modprobe tries
2935 to use a UNIX socket. But later than subsys_initcall() because
2936 we depend on stuff initialised there */
2937fs_initcall(af_unix_init);
2938module_exit(af_unix_exit);
2939
2940MODULE_LICENSE("GPL");
2941MODULE_ALIAS_NETPROTO(PF_UNIX);