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