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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
121#include "scm.h"
122
123static atomic_long_t unix_nr_socks;
124static struct hlist_head bsd_socket_buckets[UNIX_HASH_SIZE / 2];
125static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2];
126
127/* SMP locking strategy:
128 * hash table is protected with spinlock.
129 * each socket state is protected by separate spinlock.
130 */
131
132static unsigned int unix_unbound_hash(struct sock *sk)
133{
134 unsigned long hash = (unsigned long)sk;
135
136 hash ^= hash >> 16;
137 hash ^= hash >> 8;
138 hash ^= sk->sk_type;
139
140 return hash & UNIX_HASH_MOD;
141}
142
143static unsigned int unix_bsd_hash(struct inode *i)
144{
145 return i->i_ino & UNIX_HASH_MOD;
146}
147
148static unsigned int unix_abstract_hash(struct sockaddr_un *sunaddr,
149 int addr_len, int type)
150{
151 __wsum csum = csum_partial(sunaddr, addr_len, 0);
152 unsigned int hash;
153
154 hash = (__force unsigned int)csum_fold(csum);
155 hash ^= hash >> 8;
156 hash ^= type;
157
158 return UNIX_HASH_MOD + 1 + (hash & UNIX_HASH_MOD);
159}
160
161static void unix_table_double_lock(struct net *net,
162 unsigned int hash1, unsigned int hash2)
163{
164 if (hash1 == hash2) {
165 spin_lock(&net->unx.table.locks[hash1]);
166 return;
167 }
168
169 if (hash1 > hash2)
170 swap(hash1, hash2);
171
172 spin_lock(&net->unx.table.locks[hash1]);
173 spin_lock_nested(&net->unx.table.locks[hash2], SINGLE_DEPTH_NESTING);
174}
175
176static void unix_table_double_unlock(struct net *net,
177 unsigned int hash1, unsigned int hash2)
178{
179 if (hash1 == hash2) {
180 spin_unlock(&net->unx.table.locks[hash1]);
181 return;
182 }
183
184 spin_unlock(&net->unx.table.locks[hash1]);
185 spin_unlock(&net->unx.table.locks[hash2]);
186}
187
188#ifdef CONFIG_SECURITY_NETWORK
189static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
190{
191 UNIXCB(skb).secid = scm->secid;
192}
193
194static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
195{
196 scm->secid = UNIXCB(skb).secid;
197}
198
199static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
200{
201 return (scm->secid == UNIXCB(skb).secid);
202}
203#else
204static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
205{ }
206
207static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
208{ }
209
210static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
211{
212 return true;
213}
214#endif /* CONFIG_SECURITY_NETWORK */
215
216static inline int unix_our_peer(struct sock *sk, struct sock *osk)
217{
218 return unix_peer(osk) == sk;
219}
220
221static inline int unix_may_send(struct sock *sk, struct sock *osk)
222{
223 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
224}
225
226static inline int unix_recvq_full(const struct sock *sk)
227{
228 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
229}
230
231static inline int unix_recvq_full_lockless(const struct sock *sk)
232{
233 return skb_queue_len_lockless(&sk->sk_receive_queue) >
234 READ_ONCE(sk->sk_max_ack_backlog);
235}
236
237struct sock *unix_peer_get(struct sock *s)
238{
239 struct sock *peer;
240
241 unix_state_lock(s);
242 peer = unix_peer(s);
243 if (peer)
244 sock_hold(peer);
245 unix_state_unlock(s);
246 return peer;
247}
248EXPORT_SYMBOL_GPL(unix_peer_get);
249
250static struct unix_address *unix_create_addr(struct sockaddr_un *sunaddr,
251 int addr_len)
252{
253 struct unix_address *addr;
254
255 addr = kmalloc(sizeof(*addr) + addr_len, GFP_KERNEL);
256 if (!addr)
257 return NULL;
258
259 refcount_set(&addr->refcnt, 1);
260 addr->len = addr_len;
261 memcpy(addr->name, sunaddr, addr_len);
262
263 return addr;
264}
265
266static inline void unix_release_addr(struct unix_address *addr)
267{
268 if (refcount_dec_and_test(&addr->refcnt))
269 kfree(addr);
270}
271
272/*
273 * Check unix socket name:
274 * - should be not zero length.
275 * - if started by not zero, should be NULL terminated (FS object)
276 * - if started by zero, it is abstract name.
277 */
278
279static int unix_validate_addr(struct sockaddr_un *sunaddr, int addr_len)
280{
281 if (addr_len <= offsetof(struct sockaddr_un, sun_path) ||
282 addr_len > sizeof(*sunaddr))
283 return -EINVAL;
284
285 if (sunaddr->sun_family != AF_UNIX)
286 return -EINVAL;
287
288 return 0;
289}
290
291static int unix_mkname_bsd(struct sockaddr_un *sunaddr, int addr_len)
292{
293 struct sockaddr_storage *addr = (struct sockaddr_storage *)sunaddr;
294 short offset = offsetof(struct sockaddr_storage, __data);
295
296 BUILD_BUG_ON(offset != offsetof(struct sockaddr_un, sun_path));
297
298 /* This may look like an off by one error but it is a bit more
299 * subtle. 108 is the longest valid AF_UNIX path for a binding.
300 * sun_path[108] doesn't as such exist. However in kernel space
301 * we are guaranteed that it is a valid memory location in our
302 * kernel address buffer because syscall functions always pass
303 * a pointer of struct sockaddr_storage which has a bigger buffer
304 * than 108. Also, we must terminate sun_path for strlen() in
305 * getname_kernel().
306 */
307 addr->__data[addr_len - offset] = 0;
308
309 /* Don't pass sunaddr->sun_path to strlen(). Otherwise, 108 will
310 * cause panic if CONFIG_FORTIFY_SOURCE=y. Let __fortify_strlen()
311 * know the actual buffer.
312 */
313 return strlen(addr->__data) + offset + 1;
314}
315
316static void __unix_remove_socket(struct sock *sk)
317{
318 sk_del_node_init(sk);
319}
320
321static void __unix_insert_socket(struct net *net, struct sock *sk)
322{
323 DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk));
324 sk_add_node(sk, &net->unx.table.buckets[sk->sk_hash]);
325}
326
327static void __unix_set_addr_hash(struct net *net, struct sock *sk,
328 struct unix_address *addr, unsigned int hash)
329{
330 __unix_remove_socket(sk);
331 smp_store_release(&unix_sk(sk)->addr, addr);
332
333 sk->sk_hash = hash;
334 __unix_insert_socket(net, sk);
335}
336
337static void unix_remove_socket(struct net *net, struct sock *sk)
338{
339 spin_lock(&net->unx.table.locks[sk->sk_hash]);
340 __unix_remove_socket(sk);
341 spin_unlock(&net->unx.table.locks[sk->sk_hash]);
342}
343
344static void unix_insert_unbound_socket(struct net *net, struct sock *sk)
345{
346 spin_lock(&net->unx.table.locks[sk->sk_hash]);
347 __unix_insert_socket(net, sk);
348 spin_unlock(&net->unx.table.locks[sk->sk_hash]);
349}
350
351static void unix_insert_bsd_socket(struct sock *sk)
352{
353 spin_lock(&bsd_socket_locks[sk->sk_hash]);
354 sk_add_bind_node(sk, &bsd_socket_buckets[sk->sk_hash]);
355 spin_unlock(&bsd_socket_locks[sk->sk_hash]);
356}
357
358static void unix_remove_bsd_socket(struct sock *sk)
359{
360 if (!hlist_unhashed(&sk->sk_bind_node)) {
361 spin_lock(&bsd_socket_locks[sk->sk_hash]);
362 __sk_del_bind_node(sk);
363 spin_unlock(&bsd_socket_locks[sk->sk_hash]);
364
365 sk_node_init(&sk->sk_bind_node);
366 }
367}
368
369static struct sock *__unix_find_socket_byname(struct net *net,
370 struct sockaddr_un *sunname,
371 int len, unsigned int hash)
372{
373 struct sock *s;
374
375 sk_for_each(s, &net->unx.table.buckets[hash]) {
376 struct unix_sock *u = unix_sk(s);
377
378 if (u->addr->len == len &&
379 !memcmp(u->addr->name, sunname, len))
380 return s;
381 }
382 return NULL;
383}
384
385static inline struct sock *unix_find_socket_byname(struct net *net,
386 struct sockaddr_un *sunname,
387 int len, unsigned int hash)
388{
389 struct sock *s;
390
391 spin_lock(&net->unx.table.locks[hash]);
392 s = __unix_find_socket_byname(net, sunname, len, hash);
393 if (s)
394 sock_hold(s);
395 spin_unlock(&net->unx.table.locks[hash]);
396 return s;
397}
398
399static struct sock *unix_find_socket_byinode(struct inode *i)
400{
401 unsigned int hash = unix_bsd_hash(i);
402 struct sock *s;
403
404 spin_lock(&bsd_socket_locks[hash]);
405 sk_for_each_bound(s, &bsd_socket_buckets[hash]) {
406 struct dentry *dentry = unix_sk(s)->path.dentry;
407
408 if (dentry && d_backing_inode(dentry) == i) {
409 sock_hold(s);
410 spin_unlock(&bsd_socket_locks[hash]);
411 return s;
412 }
413 }
414 spin_unlock(&bsd_socket_locks[hash]);
415 return NULL;
416}
417
418/* Support code for asymmetrically connected dgram sockets
419 *
420 * If a datagram socket is connected to a socket not itself connected
421 * to the first socket (eg, /dev/log), clients may only enqueue more
422 * messages if the present receive queue of the server socket is not
423 * "too large". This means there's a second writeability condition
424 * poll and sendmsg need to test. The dgram recv code will do a wake
425 * up on the peer_wait wait queue of a socket upon reception of a
426 * datagram which needs to be propagated to sleeping would-be writers
427 * since these might not have sent anything so far. This can't be
428 * accomplished via poll_wait because the lifetime of the server
429 * socket might be less than that of its clients if these break their
430 * association with it or if the server socket is closed while clients
431 * are still connected to it and there's no way to inform "a polling
432 * implementation" that it should let go of a certain wait queue
433 *
434 * In order to propagate a wake up, a wait_queue_entry_t of the client
435 * socket is enqueued on the peer_wait queue of the server socket
436 * whose wake function does a wake_up on the ordinary client socket
437 * wait queue. This connection is established whenever a write (or
438 * poll for write) hit the flow control condition and broken when the
439 * association to the server socket is dissolved or after a wake up
440 * was relayed.
441 */
442
443static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
444 void *key)
445{
446 struct unix_sock *u;
447 wait_queue_head_t *u_sleep;
448
449 u = container_of(q, struct unix_sock, peer_wake);
450
451 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
452 q);
453 u->peer_wake.private = NULL;
454
455 /* relaying can only happen while the wq still exists */
456 u_sleep = sk_sleep(&u->sk);
457 if (u_sleep)
458 wake_up_interruptible_poll(u_sleep, key_to_poll(key));
459
460 return 0;
461}
462
463static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
464{
465 struct unix_sock *u, *u_other;
466 int rc;
467
468 u = unix_sk(sk);
469 u_other = unix_sk(other);
470 rc = 0;
471 spin_lock(&u_other->peer_wait.lock);
472
473 if (!u->peer_wake.private) {
474 u->peer_wake.private = other;
475 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
476
477 rc = 1;
478 }
479
480 spin_unlock(&u_other->peer_wait.lock);
481 return rc;
482}
483
484static void unix_dgram_peer_wake_disconnect(struct sock *sk,
485 struct sock *other)
486{
487 struct unix_sock *u, *u_other;
488
489 u = unix_sk(sk);
490 u_other = unix_sk(other);
491 spin_lock(&u_other->peer_wait.lock);
492
493 if (u->peer_wake.private == other) {
494 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
495 u->peer_wake.private = NULL;
496 }
497
498 spin_unlock(&u_other->peer_wait.lock);
499}
500
501static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
502 struct sock *other)
503{
504 unix_dgram_peer_wake_disconnect(sk, other);
505 wake_up_interruptible_poll(sk_sleep(sk),
506 EPOLLOUT |
507 EPOLLWRNORM |
508 EPOLLWRBAND);
509}
510
511/* preconditions:
512 * - unix_peer(sk) == other
513 * - association is stable
514 */
515static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
516{
517 int connected;
518
519 connected = unix_dgram_peer_wake_connect(sk, other);
520
521 /* If other is SOCK_DEAD, we want to make sure we signal
522 * POLLOUT, such that a subsequent write() can get a
523 * -ECONNREFUSED. Otherwise, if we haven't queued any skbs
524 * to other and its full, we will hang waiting for POLLOUT.
525 */
526 if (unix_recvq_full_lockless(other) && !sock_flag(other, SOCK_DEAD))
527 return 1;
528
529 if (connected)
530 unix_dgram_peer_wake_disconnect(sk, other);
531
532 return 0;
533}
534
535static int unix_writable(const struct sock *sk)
536{
537 return sk->sk_state != TCP_LISTEN &&
538 (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
539}
540
541static void unix_write_space(struct sock *sk)
542{
543 struct socket_wq *wq;
544
545 rcu_read_lock();
546 if (unix_writable(sk)) {
547 wq = rcu_dereference(sk->sk_wq);
548 if (skwq_has_sleeper(wq))
549 wake_up_interruptible_sync_poll(&wq->wait,
550 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
551 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
552 }
553 rcu_read_unlock();
554}
555
556/* When dgram socket disconnects (or changes its peer), we clear its receive
557 * queue of packets arrived from previous peer. First, it allows to do
558 * flow control based only on wmem_alloc; second, sk connected to peer
559 * may receive messages only from that peer. */
560static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
561{
562 if (!skb_queue_empty(&sk->sk_receive_queue)) {
563 skb_queue_purge(&sk->sk_receive_queue);
564 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
565
566 /* If one link of bidirectional dgram pipe is disconnected,
567 * we signal error. Messages are lost. Do not make this,
568 * when peer was not connected to us.
569 */
570 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
571 WRITE_ONCE(other->sk_err, ECONNRESET);
572 sk_error_report(other);
573 }
574 }
575 other->sk_state = TCP_CLOSE;
576}
577
578static void unix_sock_destructor(struct sock *sk)
579{
580 struct unix_sock *u = unix_sk(sk);
581
582 skb_queue_purge(&sk->sk_receive_queue);
583
584 DEBUG_NET_WARN_ON_ONCE(refcount_read(&sk->sk_wmem_alloc));
585 DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk));
586 DEBUG_NET_WARN_ON_ONCE(sk->sk_socket);
587 if (!sock_flag(sk, SOCK_DEAD)) {
588 pr_info("Attempt to release alive unix socket: %p\n", sk);
589 return;
590 }
591
592 if (u->addr)
593 unix_release_addr(u->addr);
594
595 atomic_long_dec(&unix_nr_socks);
596 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
597#ifdef UNIX_REFCNT_DEBUG
598 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
599 atomic_long_read(&unix_nr_socks));
600#endif
601}
602
603static void unix_release_sock(struct sock *sk, int embrion)
604{
605 struct unix_sock *u = unix_sk(sk);
606 struct sock *skpair;
607 struct sk_buff *skb;
608 struct path path;
609 int state;
610
611 unix_remove_socket(sock_net(sk), sk);
612 unix_remove_bsd_socket(sk);
613
614 /* Clear state */
615 unix_state_lock(sk);
616 sock_orphan(sk);
617 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
618 path = u->path;
619 u->path.dentry = NULL;
620 u->path.mnt = NULL;
621 state = sk->sk_state;
622 sk->sk_state = TCP_CLOSE;
623
624 skpair = unix_peer(sk);
625 unix_peer(sk) = NULL;
626
627 unix_state_unlock(sk);
628
629#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
630 if (u->oob_skb) {
631 kfree_skb(u->oob_skb);
632 u->oob_skb = NULL;
633 }
634#endif
635
636 wake_up_interruptible_all(&u->peer_wait);
637
638 if (skpair != NULL) {
639 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
640 unix_state_lock(skpair);
641 /* No more writes */
642 WRITE_ONCE(skpair->sk_shutdown, SHUTDOWN_MASK);
643 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
644 WRITE_ONCE(skpair->sk_err, ECONNRESET);
645 unix_state_unlock(skpair);
646 skpair->sk_state_change(skpair);
647 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
648 }
649
650 unix_dgram_peer_wake_disconnect(sk, skpair);
651 sock_put(skpair); /* It may now die */
652 }
653
654 /* Try to flush out this socket. Throw out buffers at least */
655
656 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
657 if (state == TCP_LISTEN)
658 unix_release_sock(skb->sk, 1);
659 /* passed fds are erased in the kfree_skb hook */
660 UNIXCB(skb).consumed = skb->len;
661 kfree_skb(skb);
662 }
663
664 if (path.dentry)
665 path_put(&path);
666
667 sock_put(sk);
668
669 /* ---- Socket is dead now and most probably destroyed ---- */
670
671 /*
672 * Fixme: BSD difference: In BSD all sockets connected to us get
673 * ECONNRESET and we die on the spot. In Linux we behave
674 * like files and pipes do and wait for the last
675 * dereference.
676 *
677 * Can't we simply set sock->err?
678 *
679 * What the above comment does talk about? --ANK(980817)
680 */
681
682 if (READ_ONCE(unix_tot_inflight))
683 unix_gc(); /* Garbage collect fds */
684}
685
686static void init_peercred(struct sock *sk)
687{
688 const struct cred *old_cred;
689 struct pid *old_pid;
690
691 spin_lock(&sk->sk_peer_lock);
692 old_pid = sk->sk_peer_pid;
693 old_cred = sk->sk_peer_cred;
694 sk->sk_peer_pid = get_pid(task_tgid(current));
695 sk->sk_peer_cred = get_current_cred();
696 spin_unlock(&sk->sk_peer_lock);
697
698 put_pid(old_pid);
699 put_cred(old_cred);
700}
701
702static void copy_peercred(struct sock *sk, struct sock *peersk)
703{
704 const struct cred *old_cred;
705 struct pid *old_pid;
706
707 if (sk < peersk) {
708 spin_lock(&sk->sk_peer_lock);
709 spin_lock_nested(&peersk->sk_peer_lock, SINGLE_DEPTH_NESTING);
710 } else {
711 spin_lock(&peersk->sk_peer_lock);
712 spin_lock_nested(&sk->sk_peer_lock, SINGLE_DEPTH_NESTING);
713 }
714 old_pid = sk->sk_peer_pid;
715 old_cred = sk->sk_peer_cred;
716 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
717 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
718
719 spin_unlock(&sk->sk_peer_lock);
720 spin_unlock(&peersk->sk_peer_lock);
721
722 put_pid(old_pid);
723 put_cred(old_cred);
724}
725
726static int unix_listen(struct socket *sock, int backlog)
727{
728 int err;
729 struct sock *sk = sock->sk;
730 struct unix_sock *u = unix_sk(sk);
731
732 err = -EOPNOTSUPP;
733 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
734 goto out; /* Only stream/seqpacket sockets accept */
735 err = -EINVAL;
736 if (!u->addr)
737 goto out; /* No listens on an unbound socket */
738 unix_state_lock(sk);
739 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
740 goto out_unlock;
741 if (backlog > sk->sk_max_ack_backlog)
742 wake_up_interruptible_all(&u->peer_wait);
743 sk->sk_max_ack_backlog = backlog;
744 sk->sk_state = TCP_LISTEN;
745 /* set credentials so connect can copy them */
746 init_peercred(sk);
747 err = 0;
748
749out_unlock:
750 unix_state_unlock(sk);
751out:
752 return err;
753}
754
755static int unix_release(struct socket *);
756static int unix_bind(struct socket *, struct sockaddr *, int);
757static int unix_stream_connect(struct socket *, struct sockaddr *,
758 int addr_len, int flags);
759static int unix_socketpair(struct socket *, struct socket *);
760static int unix_accept(struct socket *, struct socket *, int, bool);
761static int unix_getname(struct socket *, struct sockaddr *, int);
762static __poll_t unix_poll(struct file *, struct socket *, poll_table *);
763static __poll_t unix_dgram_poll(struct file *, struct socket *,
764 poll_table *);
765static int unix_ioctl(struct socket *, unsigned int, unsigned long);
766#ifdef CONFIG_COMPAT
767static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
768#endif
769static int unix_shutdown(struct socket *, int);
770static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
771static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
772static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
773 struct pipe_inode_info *, size_t size,
774 unsigned int flags);
775static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
776static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
777static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
778static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
779static int unix_dgram_connect(struct socket *, struct sockaddr *,
780 int, int);
781static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
782static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
783 int);
784
785#ifdef CONFIG_PROC_FS
786static int unix_count_nr_fds(struct sock *sk)
787{
788 struct sk_buff *skb;
789 struct unix_sock *u;
790 int nr_fds = 0;
791
792 spin_lock(&sk->sk_receive_queue.lock);
793 skb = skb_peek(&sk->sk_receive_queue);
794 while (skb) {
795 u = unix_sk(skb->sk);
796 nr_fds += atomic_read(&u->scm_stat.nr_fds);
797 skb = skb_peek_next(skb, &sk->sk_receive_queue);
798 }
799 spin_unlock(&sk->sk_receive_queue.lock);
800
801 return nr_fds;
802}
803
804static void unix_show_fdinfo(struct seq_file *m, struct socket *sock)
805{
806 struct sock *sk = sock->sk;
807 unsigned char s_state;
808 struct unix_sock *u;
809 int nr_fds = 0;
810
811 if (sk) {
812 s_state = READ_ONCE(sk->sk_state);
813 u = unix_sk(sk);
814
815 /* SOCK_STREAM and SOCK_SEQPACKET sockets never change their
816 * sk_state after switching to TCP_ESTABLISHED or TCP_LISTEN.
817 * SOCK_DGRAM is ordinary. So, no lock is needed.
818 */
819 if (sock->type == SOCK_DGRAM || s_state == TCP_ESTABLISHED)
820 nr_fds = atomic_read(&u->scm_stat.nr_fds);
821 else if (s_state == TCP_LISTEN)
822 nr_fds = unix_count_nr_fds(sk);
823
824 seq_printf(m, "scm_fds: %u\n", nr_fds);
825 }
826}
827#else
828#define unix_show_fdinfo NULL
829#endif
830
831static const struct proto_ops unix_stream_ops = {
832 .family = PF_UNIX,
833 .owner = THIS_MODULE,
834 .release = unix_release,
835 .bind = unix_bind,
836 .connect = unix_stream_connect,
837 .socketpair = unix_socketpair,
838 .accept = unix_accept,
839 .getname = unix_getname,
840 .poll = unix_poll,
841 .ioctl = unix_ioctl,
842#ifdef CONFIG_COMPAT
843 .compat_ioctl = unix_compat_ioctl,
844#endif
845 .listen = unix_listen,
846 .shutdown = unix_shutdown,
847 .sendmsg = unix_stream_sendmsg,
848 .recvmsg = unix_stream_recvmsg,
849 .read_skb = unix_stream_read_skb,
850 .mmap = sock_no_mmap,
851 .splice_read = unix_stream_splice_read,
852 .set_peek_off = sk_set_peek_off,
853 .show_fdinfo = unix_show_fdinfo,
854};
855
856static const struct proto_ops unix_dgram_ops = {
857 .family = PF_UNIX,
858 .owner = THIS_MODULE,
859 .release = unix_release,
860 .bind = unix_bind,
861 .connect = unix_dgram_connect,
862 .socketpair = unix_socketpair,
863 .accept = sock_no_accept,
864 .getname = unix_getname,
865 .poll = unix_dgram_poll,
866 .ioctl = unix_ioctl,
867#ifdef CONFIG_COMPAT
868 .compat_ioctl = unix_compat_ioctl,
869#endif
870 .listen = sock_no_listen,
871 .shutdown = unix_shutdown,
872 .sendmsg = unix_dgram_sendmsg,
873 .read_skb = unix_read_skb,
874 .recvmsg = unix_dgram_recvmsg,
875 .mmap = sock_no_mmap,
876 .set_peek_off = sk_set_peek_off,
877 .show_fdinfo = unix_show_fdinfo,
878};
879
880static const struct proto_ops unix_seqpacket_ops = {
881 .family = PF_UNIX,
882 .owner = THIS_MODULE,
883 .release = unix_release,
884 .bind = unix_bind,
885 .connect = unix_stream_connect,
886 .socketpair = unix_socketpair,
887 .accept = unix_accept,
888 .getname = unix_getname,
889 .poll = unix_dgram_poll,
890 .ioctl = unix_ioctl,
891#ifdef CONFIG_COMPAT
892 .compat_ioctl = unix_compat_ioctl,
893#endif
894 .listen = unix_listen,
895 .shutdown = unix_shutdown,
896 .sendmsg = unix_seqpacket_sendmsg,
897 .recvmsg = unix_seqpacket_recvmsg,
898 .mmap = sock_no_mmap,
899 .set_peek_off = sk_set_peek_off,
900 .show_fdinfo = unix_show_fdinfo,
901};
902
903static void unix_close(struct sock *sk, long timeout)
904{
905 /* Nothing to do here, unix socket does not need a ->close().
906 * This is merely for sockmap.
907 */
908}
909
910static void unix_unhash(struct sock *sk)
911{
912 /* Nothing to do here, unix socket does not need a ->unhash().
913 * This is merely for sockmap.
914 */
915}
916
917static bool unix_bpf_bypass_getsockopt(int level, int optname)
918{
919 if (level == SOL_SOCKET) {
920 switch (optname) {
921 case SO_PEERPIDFD:
922 return true;
923 default:
924 return false;
925 }
926 }
927
928 return false;
929}
930
931struct proto unix_dgram_proto = {
932 .name = "UNIX",
933 .owner = THIS_MODULE,
934 .obj_size = sizeof(struct unix_sock),
935 .close = unix_close,
936 .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt,
937#ifdef CONFIG_BPF_SYSCALL
938 .psock_update_sk_prot = unix_dgram_bpf_update_proto,
939#endif
940};
941
942struct proto unix_stream_proto = {
943 .name = "UNIX-STREAM",
944 .owner = THIS_MODULE,
945 .obj_size = sizeof(struct unix_sock),
946 .close = unix_close,
947 .unhash = unix_unhash,
948 .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt,
949#ifdef CONFIG_BPF_SYSCALL
950 .psock_update_sk_prot = unix_stream_bpf_update_proto,
951#endif
952};
953
954static struct sock *unix_create1(struct net *net, struct socket *sock, int kern, int type)
955{
956 struct unix_sock *u;
957 struct sock *sk;
958 int err;
959
960 atomic_long_inc(&unix_nr_socks);
961 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) {
962 err = -ENFILE;
963 goto err;
964 }
965
966 if (type == SOCK_STREAM)
967 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_stream_proto, kern);
968 else /*dgram and seqpacket */
969 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_dgram_proto, kern);
970
971 if (!sk) {
972 err = -ENOMEM;
973 goto err;
974 }
975
976 sock_init_data(sock, sk);
977
978 sk->sk_hash = unix_unbound_hash(sk);
979 sk->sk_allocation = GFP_KERNEL_ACCOUNT;
980 sk->sk_write_space = unix_write_space;
981 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
982 sk->sk_destruct = unix_sock_destructor;
983 u = unix_sk(sk);
984 u->path.dentry = NULL;
985 u->path.mnt = NULL;
986 spin_lock_init(&u->lock);
987 atomic_long_set(&u->inflight, 0);
988 INIT_LIST_HEAD(&u->link);
989 mutex_init(&u->iolock); /* single task reading lock */
990 mutex_init(&u->bindlock); /* single task binding lock */
991 init_waitqueue_head(&u->peer_wait);
992 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
993 memset(&u->scm_stat, 0, sizeof(struct scm_stat));
994 unix_insert_unbound_socket(net, sk);
995
996 sock_prot_inuse_add(net, sk->sk_prot, 1);
997
998 return sk;
999
1000err:
1001 atomic_long_dec(&unix_nr_socks);
1002 return ERR_PTR(err);
1003}
1004
1005static int unix_create(struct net *net, struct socket *sock, int protocol,
1006 int kern)
1007{
1008 struct sock *sk;
1009
1010 if (protocol && protocol != PF_UNIX)
1011 return -EPROTONOSUPPORT;
1012
1013 sock->state = SS_UNCONNECTED;
1014
1015 switch (sock->type) {
1016 case SOCK_STREAM:
1017 sock->ops = &unix_stream_ops;
1018 break;
1019 /*
1020 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
1021 * nothing uses it.
1022 */
1023 case SOCK_RAW:
1024 sock->type = SOCK_DGRAM;
1025 fallthrough;
1026 case SOCK_DGRAM:
1027 sock->ops = &unix_dgram_ops;
1028 break;
1029 case SOCK_SEQPACKET:
1030 sock->ops = &unix_seqpacket_ops;
1031 break;
1032 default:
1033 return -ESOCKTNOSUPPORT;
1034 }
1035
1036 sk = unix_create1(net, sock, kern, sock->type);
1037 if (IS_ERR(sk))
1038 return PTR_ERR(sk);
1039
1040 return 0;
1041}
1042
1043static int unix_release(struct socket *sock)
1044{
1045 struct sock *sk = sock->sk;
1046
1047 if (!sk)
1048 return 0;
1049
1050 sk->sk_prot->close(sk, 0);
1051 unix_release_sock(sk, 0);
1052 sock->sk = NULL;
1053
1054 return 0;
1055}
1056
1057static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len,
1058 int type)
1059{
1060 struct inode *inode;
1061 struct path path;
1062 struct sock *sk;
1063 int err;
1064
1065 unix_mkname_bsd(sunaddr, addr_len);
1066 err = kern_path(sunaddr->sun_path, LOOKUP_FOLLOW, &path);
1067 if (err)
1068 goto fail;
1069
1070 err = path_permission(&path, MAY_WRITE);
1071 if (err)
1072 goto path_put;
1073
1074 err = -ECONNREFUSED;
1075 inode = d_backing_inode(path.dentry);
1076 if (!S_ISSOCK(inode->i_mode))
1077 goto path_put;
1078
1079 sk = unix_find_socket_byinode(inode);
1080 if (!sk)
1081 goto path_put;
1082
1083 err = -EPROTOTYPE;
1084 if (sk->sk_type == type)
1085 touch_atime(&path);
1086 else
1087 goto sock_put;
1088
1089 path_put(&path);
1090
1091 return sk;
1092
1093sock_put:
1094 sock_put(sk);
1095path_put:
1096 path_put(&path);
1097fail:
1098 return ERR_PTR(err);
1099}
1100
1101static struct sock *unix_find_abstract(struct net *net,
1102 struct sockaddr_un *sunaddr,
1103 int addr_len, int type)
1104{
1105 unsigned int hash = unix_abstract_hash(sunaddr, addr_len, type);
1106 struct dentry *dentry;
1107 struct sock *sk;
1108
1109 sk = unix_find_socket_byname(net, sunaddr, addr_len, hash);
1110 if (!sk)
1111 return ERR_PTR(-ECONNREFUSED);
1112
1113 dentry = unix_sk(sk)->path.dentry;
1114 if (dentry)
1115 touch_atime(&unix_sk(sk)->path);
1116
1117 return sk;
1118}
1119
1120static struct sock *unix_find_other(struct net *net,
1121 struct sockaddr_un *sunaddr,
1122 int addr_len, int type)
1123{
1124 struct sock *sk;
1125
1126 if (sunaddr->sun_path[0])
1127 sk = unix_find_bsd(sunaddr, addr_len, type);
1128 else
1129 sk = unix_find_abstract(net, sunaddr, addr_len, type);
1130
1131 return sk;
1132}
1133
1134static int unix_autobind(struct sock *sk)
1135{
1136 unsigned int new_hash, old_hash = sk->sk_hash;
1137 struct unix_sock *u = unix_sk(sk);
1138 struct net *net = sock_net(sk);
1139 struct unix_address *addr;
1140 u32 lastnum, ordernum;
1141 int err;
1142
1143 err = mutex_lock_interruptible(&u->bindlock);
1144 if (err)
1145 return err;
1146
1147 if (u->addr)
1148 goto out;
1149
1150 err = -ENOMEM;
1151 addr = kzalloc(sizeof(*addr) +
1152 offsetof(struct sockaddr_un, sun_path) + 16, GFP_KERNEL);
1153 if (!addr)
1154 goto out;
1155
1156 addr->len = offsetof(struct sockaddr_un, sun_path) + 6;
1157 addr->name->sun_family = AF_UNIX;
1158 refcount_set(&addr->refcnt, 1);
1159
1160 ordernum = get_random_u32();
1161 lastnum = ordernum & 0xFFFFF;
1162retry:
1163 ordernum = (ordernum + 1) & 0xFFFFF;
1164 sprintf(addr->name->sun_path + 1, "%05x", ordernum);
1165
1166 new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);
1167 unix_table_double_lock(net, old_hash, new_hash);
1168
1169 if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) {
1170 unix_table_double_unlock(net, old_hash, new_hash);
1171
1172 /* __unix_find_socket_byname() may take long time if many names
1173 * are already in use.
1174 */
1175 cond_resched();
1176
1177 if (ordernum == lastnum) {
1178 /* Give up if all names seems to be in use. */
1179 err = -ENOSPC;
1180 unix_release_addr(addr);
1181 goto out;
1182 }
1183
1184 goto retry;
1185 }
1186
1187 __unix_set_addr_hash(net, sk, addr, new_hash);
1188 unix_table_double_unlock(net, old_hash, new_hash);
1189 err = 0;
1190
1191out: mutex_unlock(&u->bindlock);
1192 return err;
1193}
1194
1195static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr,
1196 int addr_len)
1197{
1198 umode_t mode = S_IFSOCK |
1199 (SOCK_INODE(sk->sk_socket)->i_mode & ~current_umask());
1200 unsigned int new_hash, old_hash = sk->sk_hash;
1201 struct unix_sock *u = unix_sk(sk);
1202 struct net *net = sock_net(sk);
1203 struct mnt_idmap *idmap;
1204 struct unix_address *addr;
1205 struct dentry *dentry;
1206 struct path parent;
1207 int err;
1208
1209 addr_len = unix_mkname_bsd(sunaddr, addr_len);
1210 addr = unix_create_addr(sunaddr, addr_len);
1211 if (!addr)
1212 return -ENOMEM;
1213
1214 /*
1215 * Get the parent directory, calculate the hash for last
1216 * component.
1217 */
1218 dentry = kern_path_create(AT_FDCWD, addr->name->sun_path, &parent, 0);
1219 if (IS_ERR(dentry)) {
1220 err = PTR_ERR(dentry);
1221 goto out;
1222 }
1223
1224 /*
1225 * All right, let's create it.
1226 */
1227 idmap = mnt_idmap(parent.mnt);
1228 err = security_path_mknod(&parent, dentry, mode, 0);
1229 if (!err)
1230 err = vfs_mknod(idmap, d_inode(parent.dentry), dentry, mode, 0);
1231 if (err)
1232 goto out_path;
1233 err = mutex_lock_interruptible(&u->bindlock);
1234 if (err)
1235 goto out_unlink;
1236 if (u->addr)
1237 goto out_unlock;
1238
1239 new_hash = unix_bsd_hash(d_backing_inode(dentry));
1240 unix_table_double_lock(net, old_hash, new_hash);
1241 u->path.mnt = mntget(parent.mnt);
1242 u->path.dentry = dget(dentry);
1243 __unix_set_addr_hash(net, sk, addr, new_hash);
1244 unix_table_double_unlock(net, old_hash, new_hash);
1245 unix_insert_bsd_socket(sk);
1246 mutex_unlock(&u->bindlock);
1247 done_path_create(&parent, dentry);
1248 return 0;
1249
1250out_unlock:
1251 mutex_unlock(&u->bindlock);
1252 err = -EINVAL;
1253out_unlink:
1254 /* failed after successful mknod? unlink what we'd created... */
1255 vfs_unlink(idmap, d_inode(parent.dentry), dentry, NULL);
1256out_path:
1257 done_path_create(&parent, dentry);
1258out:
1259 unix_release_addr(addr);
1260 return err == -EEXIST ? -EADDRINUSE : err;
1261}
1262
1263static int unix_bind_abstract(struct sock *sk, struct sockaddr_un *sunaddr,
1264 int addr_len)
1265{
1266 unsigned int new_hash, old_hash = sk->sk_hash;
1267 struct unix_sock *u = unix_sk(sk);
1268 struct net *net = sock_net(sk);
1269 struct unix_address *addr;
1270 int err;
1271
1272 addr = unix_create_addr(sunaddr, addr_len);
1273 if (!addr)
1274 return -ENOMEM;
1275
1276 err = mutex_lock_interruptible(&u->bindlock);
1277 if (err)
1278 goto out;
1279
1280 if (u->addr) {
1281 err = -EINVAL;
1282 goto out_mutex;
1283 }
1284
1285 new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);
1286 unix_table_double_lock(net, old_hash, new_hash);
1287
1288 if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash))
1289 goto out_spin;
1290
1291 __unix_set_addr_hash(net, sk, addr, new_hash);
1292 unix_table_double_unlock(net, old_hash, new_hash);
1293 mutex_unlock(&u->bindlock);
1294 return 0;
1295
1296out_spin:
1297 unix_table_double_unlock(net, old_hash, new_hash);
1298 err = -EADDRINUSE;
1299out_mutex:
1300 mutex_unlock(&u->bindlock);
1301out:
1302 unix_release_addr(addr);
1303 return err;
1304}
1305
1306static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
1307{
1308 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1309 struct sock *sk = sock->sk;
1310 int err;
1311
1312 if (addr_len == offsetof(struct sockaddr_un, sun_path) &&
1313 sunaddr->sun_family == AF_UNIX)
1314 return unix_autobind(sk);
1315
1316 err = unix_validate_addr(sunaddr, addr_len);
1317 if (err)
1318 return err;
1319
1320 if (sunaddr->sun_path[0])
1321 err = unix_bind_bsd(sk, sunaddr, addr_len);
1322 else
1323 err = unix_bind_abstract(sk, sunaddr, addr_len);
1324
1325 return err;
1326}
1327
1328static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1329{
1330 if (unlikely(sk1 == sk2) || !sk2) {
1331 unix_state_lock(sk1);
1332 return;
1333 }
1334 if (sk1 > sk2)
1335 swap(sk1, sk2);
1336
1337 unix_state_lock(sk1);
1338 unix_state_lock_nested(sk2, U_LOCK_SECOND);
1339}
1340
1341static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1342{
1343 if (unlikely(sk1 == sk2) || !sk2) {
1344 unix_state_unlock(sk1);
1345 return;
1346 }
1347 unix_state_unlock(sk1);
1348 unix_state_unlock(sk2);
1349}
1350
1351static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1352 int alen, int flags)
1353{
1354 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1355 struct sock *sk = sock->sk;
1356 struct sock *other;
1357 int err;
1358
1359 err = -EINVAL;
1360 if (alen < offsetofend(struct sockaddr, sa_family))
1361 goto out;
1362
1363 if (addr->sa_family != AF_UNSPEC) {
1364 err = unix_validate_addr(sunaddr, alen);
1365 if (err)
1366 goto out;
1367
1368 err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, addr, &alen);
1369 if (err)
1370 goto out;
1371
1372 if ((test_bit(SOCK_PASSCRED, &sock->flags) ||
1373 test_bit(SOCK_PASSPIDFD, &sock->flags)) &&
1374 !unix_sk(sk)->addr) {
1375 err = unix_autobind(sk);
1376 if (err)
1377 goto out;
1378 }
1379
1380restart:
1381 other = unix_find_other(sock_net(sk), sunaddr, alen, sock->type);
1382 if (IS_ERR(other)) {
1383 err = PTR_ERR(other);
1384 goto out;
1385 }
1386
1387 unix_state_double_lock(sk, other);
1388
1389 /* Apparently VFS overslept socket death. Retry. */
1390 if (sock_flag(other, SOCK_DEAD)) {
1391 unix_state_double_unlock(sk, other);
1392 sock_put(other);
1393 goto restart;
1394 }
1395
1396 err = -EPERM;
1397 if (!unix_may_send(sk, other))
1398 goto out_unlock;
1399
1400 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1401 if (err)
1402 goto out_unlock;
1403
1404 sk->sk_state = other->sk_state = TCP_ESTABLISHED;
1405 } else {
1406 /*
1407 * 1003.1g breaking connected state with AF_UNSPEC
1408 */
1409 other = NULL;
1410 unix_state_double_lock(sk, other);
1411 }
1412
1413 /*
1414 * If it was connected, reconnect.
1415 */
1416 if (unix_peer(sk)) {
1417 struct sock *old_peer = unix_peer(sk);
1418
1419 unix_peer(sk) = other;
1420 if (!other)
1421 sk->sk_state = TCP_CLOSE;
1422 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1423
1424 unix_state_double_unlock(sk, other);
1425
1426 if (other != old_peer)
1427 unix_dgram_disconnected(sk, old_peer);
1428 sock_put(old_peer);
1429 } else {
1430 unix_peer(sk) = other;
1431 unix_state_double_unlock(sk, other);
1432 }
1433
1434 return 0;
1435
1436out_unlock:
1437 unix_state_double_unlock(sk, other);
1438 sock_put(other);
1439out:
1440 return err;
1441}
1442
1443static long unix_wait_for_peer(struct sock *other, long timeo)
1444 __releases(&unix_sk(other)->lock)
1445{
1446 struct unix_sock *u = unix_sk(other);
1447 int sched;
1448 DEFINE_WAIT(wait);
1449
1450 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1451
1452 sched = !sock_flag(other, SOCK_DEAD) &&
1453 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1454 unix_recvq_full_lockless(other);
1455
1456 unix_state_unlock(other);
1457
1458 if (sched)
1459 timeo = schedule_timeout(timeo);
1460
1461 finish_wait(&u->peer_wait, &wait);
1462 return timeo;
1463}
1464
1465static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1466 int addr_len, int flags)
1467{
1468 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1469 struct sock *sk = sock->sk, *newsk = NULL, *other = NULL;
1470 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1471 struct net *net = sock_net(sk);
1472 struct sk_buff *skb = NULL;
1473 long timeo;
1474 int err;
1475 int st;
1476
1477 err = unix_validate_addr(sunaddr, addr_len);
1478 if (err)
1479 goto out;
1480
1481 err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, uaddr, &addr_len);
1482 if (err)
1483 goto out;
1484
1485 if ((test_bit(SOCK_PASSCRED, &sock->flags) ||
1486 test_bit(SOCK_PASSPIDFD, &sock->flags)) && !u->addr) {
1487 err = unix_autobind(sk);
1488 if (err)
1489 goto out;
1490 }
1491
1492 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1493
1494 /* First of all allocate resources.
1495 If we will make it after state is locked,
1496 we will have to recheck all again in any case.
1497 */
1498
1499 /* create new sock for complete connection */
1500 newsk = unix_create1(net, NULL, 0, sock->type);
1501 if (IS_ERR(newsk)) {
1502 err = PTR_ERR(newsk);
1503 newsk = NULL;
1504 goto out;
1505 }
1506
1507 err = -ENOMEM;
1508
1509 /* Allocate skb for sending to listening sock */
1510 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1511 if (skb == NULL)
1512 goto out;
1513
1514restart:
1515 /* Find listening sock. */
1516 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type);
1517 if (IS_ERR(other)) {
1518 err = PTR_ERR(other);
1519 other = NULL;
1520 goto out;
1521 }
1522
1523 /* Latch state of peer */
1524 unix_state_lock(other);
1525
1526 /* Apparently VFS overslept socket death. Retry. */
1527 if (sock_flag(other, SOCK_DEAD)) {
1528 unix_state_unlock(other);
1529 sock_put(other);
1530 goto restart;
1531 }
1532
1533 err = -ECONNREFUSED;
1534 if (other->sk_state != TCP_LISTEN)
1535 goto out_unlock;
1536 if (other->sk_shutdown & RCV_SHUTDOWN)
1537 goto out_unlock;
1538
1539 if (unix_recvq_full(other)) {
1540 err = -EAGAIN;
1541 if (!timeo)
1542 goto out_unlock;
1543
1544 timeo = unix_wait_for_peer(other, timeo);
1545
1546 err = sock_intr_errno(timeo);
1547 if (signal_pending(current))
1548 goto out;
1549 sock_put(other);
1550 goto restart;
1551 }
1552
1553 /* Latch our state.
1554
1555 It is tricky place. We need to grab our state lock and cannot
1556 drop lock on peer. It is dangerous because deadlock is
1557 possible. Connect to self case and simultaneous
1558 attempt to connect are eliminated by checking socket
1559 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1560 check this before attempt to grab lock.
1561
1562 Well, and we have to recheck the state after socket locked.
1563 */
1564 st = sk->sk_state;
1565
1566 switch (st) {
1567 case TCP_CLOSE:
1568 /* This is ok... continue with connect */
1569 break;
1570 case TCP_ESTABLISHED:
1571 /* Socket is already connected */
1572 err = -EISCONN;
1573 goto out_unlock;
1574 default:
1575 err = -EINVAL;
1576 goto out_unlock;
1577 }
1578
1579 unix_state_lock_nested(sk, U_LOCK_SECOND);
1580
1581 if (sk->sk_state != st) {
1582 unix_state_unlock(sk);
1583 unix_state_unlock(other);
1584 sock_put(other);
1585 goto restart;
1586 }
1587
1588 err = security_unix_stream_connect(sk, other, newsk);
1589 if (err) {
1590 unix_state_unlock(sk);
1591 goto out_unlock;
1592 }
1593
1594 /* The way is open! Fastly set all the necessary fields... */
1595
1596 sock_hold(sk);
1597 unix_peer(newsk) = sk;
1598 newsk->sk_state = TCP_ESTABLISHED;
1599 newsk->sk_type = sk->sk_type;
1600 init_peercred(newsk);
1601 newu = unix_sk(newsk);
1602 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1603 otheru = unix_sk(other);
1604
1605 /* copy address information from listening to new sock
1606 *
1607 * The contents of *(otheru->addr) and otheru->path
1608 * are seen fully set up here, since we have found
1609 * otheru in hash under its lock. Insertion into the
1610 * hash chain we'd found it in had been done in an
1611 * earlier critical area protected by the chain's lock,
1612 * the same one where we'd set *(otheru->addr) contents,
1613 * as well as otheru->path and otheru->addr itself.
1614 *
1615 * Using smp_store_release() here to set newu->addr
1616 * is enough to make those stores, as well as stores
1617 * to newu->path visible to anyone who gets newu->addr
1618 * by smp_load_acquire(). IOW, the same warranties
1619 * as for unix_sock instances bound in unix_bind() or
1620 * in unix_autobind().
1621 */
1622 if (otheru->path.dentry) {
1623 path_get(&otheru->path);
1624 newu->path = otheru->path;
1625 }
1626 refcount_inc(&otheru->addr->refcnt);
1627 smp_store_release(&newu->addr, otheru->addr);
1628
1629 /* Set credentials */
1630 copy_peercred(sk, other);
1631
1632 sock->state = SS_CONNECTED;
1633 sk->sk_state = TCP_ESTABLISHED;
1634 sock_hold(newsk);
1635
1636 smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1637 unix_peer(sk) = newsk;
1638
1639 unix_state_unlock(sk);
1640
1641 /* take ten and send info to listening sock */
1642 spin_lock(&other->sk_receive_queue.lock);
1643 __skb_queue_tail(&other->sk_receive_queue, skb);
1644 spin_unlock(&other->sk_receive_queue.lock);
1645 unix_state_unlock(other);
1646 other->sk_data_ready(other);
1647 sock_put(other);
1648 return 0;
1649
1650out_unlock:
1651 if (other)
1652 unix_state_unlock(other);
1653
1654out:
1655 kfree_skb(skb);
1656 if (newsk)
1657 unix_release_sock(newsk, 0);
1658 if (other)
1659 sock_put(other);
1660 return err;
1661}
1662
1663static int unix_socketpair(struct socket *socka, struct socket *sockb)
1664{
1665 struct sock *ska = socka->sk, *skb = sockb->sk;
1666
1667 /* Join our sockets back to back */
1668 sock_hold(ska);
1669 sock_hold(skb);
1670 unix_peer(ska) = skb;
1671 unix_peer(skb) = ska;
1672 init_peercred(ska);
1673 init_peercred(skb);
1674
1675 ska->sk_state = TCP_ESTABLISHED;
1676 skb->sk_state = TCP_ESTABLISHED;
1677 socka->state = SS_CONNECTED;
1678 sockb->state = SS_CONNECTED;
1679 return 0;
1680}
1681
1682static void unix_sock_inherit_flags(const struct socket *old,
1683 struct socket *new)
1684{
1685 if (test_bit(SOCK_PASSCRED, &old->flags))
1686 set_bit(SOCK_PASSCRED, &new->flags);
1687 if (test_bit(SOCK_PASSPIDFD, &old->flags))
1688 set_bit(SOCK_PASSPIDFD, &new->flags);
1689 if (test_bit(SOCK_PASSSEC, &old->flags))
1690 set_bit(SOCK_PASSSEC, &new->flags);
1691}
1692
1693static int unix_accept(struct socket *sock, struct socket *newsock, int flags,
1694 bool kern)
1695{
1696 struct sock *sk = sock->sk;
1697 struct sock *tsk;
1698 struct sk_buff *skb;
1699 int err;
1700
1701 err = -EOPNOTSUPP;
1702 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1703 goto out;
1704
1705 err = -EINVAL;
1706 if (sk->sk_state != TCP_LISTEN)
1707 goto out;
1708
1709 /* If socket state is TCP_LISTEN it cannot change (for now...),
1710 * so that no locks are necessary.
1711 */
1712
1713 skb = skb_recv_datagram(sk, (flags & O_NONBLOCK) ? MSG_DONTWAIT : 0,
1714 &err);
1715 if (!skb) {
1716 /* This means receive shutdown. */
1717 if (err == 0)
1718 err = -EINVAL;
1719 goto out;
1720 }
1721
1722 tsk = skb->sk;
1723 skb_free_datagram(sk, skb);
1724 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1725
1726 /* attach accepted sock to socket */
1727 unix_state_lock(tsk);
1728 newsock->state = SS_CONNECTED;
1729 unix_sock_inherit_flags(sock, newsock);
1730 sock_graft(tsk, newsock);
1731 unix_state_unlock(tsk);
1732 return 0;
1733
1734out:
1735 return err;
1736}
1737
1738
1739static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1740{
1741 struct sock *sk = sock->sk;
1742 struct unix_address *addr;
1743 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1744 int err = 0;
1745
1746 if (peer) {
1747 sk = unix_peer_get(sk);
1748
1749 err = -ENOTCONN;
1750 if (!sk)
1751 goto out;
1752 err = 0;
1753 } else {
1754 sock_hold(sk);
1755 }
1756
1757 addr = smp_load_acquire(&unix_sk(sk)->addr);
1758 if (!addr) {
1759 sunaddr->sun_family = AF_UNIX;
1760 sunaddr->sun_path[0] = 0;
1761 err = offsetof(struct sockaddr_un, sun_path);
1762 } else {
1763 err = addr->len;
1764 memcpy(sunaddr, addr->name, addr->len);
1765
1766 if (peer)
1767 BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err,
1768 CGROUP_UNIX_GETPEERNAME);
1769 else
1770 BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err,
1771 CGROUP_UNIX_GETSOCKNAME);
1772 }
1773 sock_put(sk);
1774out:
1775 return err;
1776}
1777
1778static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb)
1779{
1780 scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1781
1782 /*
1783 * Garbage collection of unix sockets starts by selecting a set of
1784 * candidate sockets which have reference only from being in flight
1785 * (total_refs == inflight_refs). This condition is checked once during
1786 * the candidate collection phase, and candidates are marked as such, so
1787 * that non-candidates can later be ignored. While inflight_refs is
1788 * protected by unix_gc_lock, total_refs (file count) is not, hence this
1789 * is an instantaneous decision.
1790 *
1791 * Once a candidate, however, the socket must not be reinstalled into a
1792 * file descriptor while the garbage collection is in progress.
1793 *
1794 * If the above conditions are met, then the directed graph of
1795 * candidates (*) does not change while unix_gc_lock is held.
1796 *
1797 * Any operations that changes the file count through file descriptors
1798 * (dup, close, sendmsg) does not change the graph since candidates are
1799 * not installed in fds.
1800 *
1801 * Dequeing a candidate via recvmsg would install it into an fd, but
1802 * that takes unix_gc_lock to decrement the inflight count, so it's
1803 * serialized with garbage collection.
1804 *
1805 * MSG_PEEK is special in that it does not change the inflight count,
1806 * yet does install the socket into an fd. The following lock/unlock
1807 * pair is to ensure serialization with garbage collection. It must be
1808 * done between incrementing the file count and installing the file into
1809 * an fd.
1810 *
1811 * If garbage collection starts after the barrier provided by the
1812 * lock/unlock, then it will see the elevated refcount and not mark this
1813 * as a candidate. If a garbage collection is already in progress
1814 * before the file count was incremented, then the lock/unlock pair will
1815 * ensure that garbage collection is finished before progressing to
1816 * installing the fd.
1817 *
1818 * (*) A -> B where B is on the queue of A or B is on the queue of C
1819 * which is on the queue of listening socket A.
1820 */
1821 spin_lock(&unix_gc_lock);
1822 spin_unlock(&unix_gc_lock);
1823}
1824
1825static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1826{
1827 int err = 0;
1828
1829 UNIXCB(skb).pid = get_pid(scm->pid);
1830 UNIXCB(skb).uid = scm->creds.uid;
1831 UNIXCB(skb).gid = scm->creds.gid;
1832 UNIXCB(skb).fp = NULL;
1833 unix_get_secdata(scm, skb);
1834 if (scm->fp && send_fds)
1835 err = unix_attach_fds(scm, skb);
1836
1837 skb->destructor = unix_destruct_scm;
1838 return err;
1839}
1840
1841static bool unix_passcred_enabled(const struct socket *sock,
1842 const struct sock *other)
1843{
1844 return test_bit(SOCK_PASSCRED, &sock->flags) ||
1845 test_bit(SOCK_PASSPIDFD, &sock->flags) ||
1846 !other->sk_socket ||
1847 test_bit(SOCK_PASSCRED, &other->sk_socket->flags) ||
1848 test_bit(SOCK_PASSPIDFD, &other->sk_socket->flags);
1849}
1850
1851/*
1852 * Some apps rely on write() giving SCM_CREDENTIALS
1853 * We include credentials if source or destination socket
1854 * asserted SOCK_PASSCRED.
1855 */
1856static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1857 const struct sock *other)
1858{
1859 if (UNIXCB(skb).pid)
1860 return;
1861 if (unix_passcred_enabled(sock, other)) {
1862 UNIXCB(skb).pid = get_pid(task_tgid(current));
1863 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1864 }
1865}
1866
1867static bool unix_skb_scm_eq(struct sk_buff *skb,
1868 struct scm_cookie *scm)
1869{
1870 return UNIXCB(skb).pid == scm->pid &&
1871 uid_eq(UNIXCB(skb).uid, scm->creds.uid) &&
1872 gid_eq(UNIXCB(skb).gid, scm->creds.gid) &&
1873 unix_secdata_eq(scm, skb);
1874}
1875
1876static void scm_stat_add(struct sock *sk, struct sk_buff *skb)
1877{
1878 struct scm_fp_list *fp = UNIXCB(skb).fp;
1879 struct unix_sock *u = unix_sk(sk);
1880
1881 if (unlikely(fp && fp->count))
1882 atomic_add(fp->count, &u->scm_stat.nr_fds);
1883}
1884
1885static void scm_stat_del(struct sock *sk, struct sk_buff *skb)
1886{
1887 struct scm_fp_list *fp = UNIXCB(skb).fp;
1888 struct unix_sock *u = unix_sk(sk);
1889
1890 if (unlikely(fp && fp->count))
1891 atomic_sub(fp->count, &u->scm_stat.nr_fds);
1892}
1893
1894/*
1895 * Send AF_UNIX data.
1896 */
1897
1898static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1899 size_t len)
1900{
1901 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1902 struct sock *sk = sock->sk, *other = NULL;
1903 struct unix_sock *u = unix_sk(sk);
1904 struct scm_cookie scm;
1905 struct sk_buff *skb;
1906 int data_len = 0;
1907 int sk_locked;
1908 long timeo;
1909 int err;
1910
1911 wait_for_unix_gc();
1912 err = scm_send(sock, msg, &scm, false);
1913 if (err < 0)
1914 return err;
1915
1916 err = -EOPNOTSUPP;
1917 if (msg->msg_flags&MSG_OOB)
1918 goto out;
1919
1920 if (msg->msg_namelen) {
1921 err = unix_validate_addr(sunaddr, msg->msg_namelen);
1922 if (err)
1923 goto out;
1924
1925 err = BPF_CGROUP_RUN_PROG_UNIX_SENDMSG_LOCK(sk,
1926 msg->msg_name,
1927 &msg->msg_namelen,
1928 NULL);
1929 if (err)
1930 goto out;
1931 } else {
1932 sunaddr = NULL;
1933 err = -ENOTCONN;
1934 other = unix_peer_get(sk);
1935 if (!other)
1936 goto out;
1937 }
1938
1939 if ((test_bit(SOCK_PASSCRED, &sock->flags) ||
1940 test_bit(SOCK_PASSPIDFD, &sock->flags)) && !u->addr) {
1941 err = unix_autobind(sk);
1942 if (err)
1943 goto out;
1944 }
1945
1946 err = -EMSGSIZE;
1947 if (len > sk->sk_sndbuf - 32)
1948 goto out;
1949
1950 if (len > SKB_MAX_ALLOC) {
1951 data_len = min_t(size_t,
1952 len - SKB_MAX_ALLOC,
1953 MAX_SKB_FRAGS * PAGE_SIZE);
1954 data_len = PAGE_ALIGN(data_len);
1955
1956 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1957 }
1958
1959 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1960 msg->msg_flags & MSG_DONTWAIT, &err,
1961 PAGE_ALLOC_COSTLY_ORDER);
1962 if (skb == NULL)
1963 goto out;
1964
1965 err = unix_scm_to_skb(&scm, skb, true);
1966 if (err < 0)
1967 goto out_free;
1968
1969 skb_put(skb, len - data_len);
1970 skb->data_len = data_len;
1971 skb->len = len;
1972 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1973 if (err)
1974 goto out_free;
1975
1976 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1977
1978restart:
1979 if (!other) {
1980 err = -ECONNRESET;
1981 if (sunaddr == NULL)
1982 goto out_free;
1983
1984 other = unix_find_other(sock_net(sk), sunaddr, msg->msg_namelen,
1985 sk->sk_type);
1986 if (IS_ERR(other)) {
1987 err = PTR_ERR(other);
1988 other = NULL;
1989 goto out_free;
1990 }
1991 }
1992
1993 if (sk_filter(other, skb) < 0) {
1994 /* Toss the packet but do not return any error to the sender */
1995 err = len;
1996 goto out_free;
1997 }
1998
1999 sk_locked = 0;
2000 unix_state_lock(other);
2001restart_locked:
2002 err = -EPERM;
2003 if (!unix_may_send(sk, other))
2004 goto out_unlock;
2005
2006 if (unlikely(sock_flag(other, SOCK_DEAD))) {
2007 /*
2008 * Check with 1003.1g - what should
2009 * datagram error
2010 */
2011 unix_state_unlock(other);
2012 sock_put(other);
2013
2014 if (!sk_locked)
2015 unix_state_lock(sk);
2016
2017 err = 0;
2018 if (sk->sk_type == SOCK_SEQPACKET) {
2019 /* We are here only when racing with unix_release_sock()
2020 * is clearing @other. Never change state to TCP_CLOSE
2021 * unlike SOCK_DGRAM wants.
2022 */
2023 unix_state_unlock(sk);
2024 err = -EPIPE;
2025 } else if (unix_peer(sk) == other) {
2026 unix_peer(sk) = NULL;
2027 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
2028
2029 sk->sk_state = TCP_CLOSE;
2030 unix_state_unlock(sk);
2031
2032 unix_dgram_disconnected(sk, other);
2033 sock_put(other);
2034 err = -ECONNREFUSED;
2035 } else {
2036 unix_state_unlock(sk);
2037 }
2038
2039 other = NULL;
2040 if (err)
2041 goto out_free;
2042 goto restart;
2043 }
2044
2045 err = -EPIPE;
2046 if (other->sk_shutdown & RCV_SHUTDOWN)
2047 goto out_unlock;
2048
2049 if (sk->sk_type != SOCK_SEQPACKET) {
2050 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
2051 if (err)
2052 goto out_unlock;
2053 }
2054
2055 /* other == sk && unix_peer(other) != sk if
2056 * - unix_peer(sk) == NULL, destination address bound to sk
2057 * - unix_peer(sk) == sk by time of get but disconnected before lock
2058 */
2059 if (other != sk &&
2060 unlikely(unix_peer(other) != sk &&
2061 unix_recvq_full_lockless(other))) {
2062 if (timeo) {
2063 timeo = unix_wait_for_peer(other, timeo);
2064
2065 err = sock_intr_errno(timeo);
2066 if (signal_pending(current))
2067 goto out_free;
2068
2069 goto restart;
2070 }
2071
2072 if (!sk_locked) {
2073 unix_state_unlock(other);
2074 unix_state_double_lock(sk, other);
2075 }
2076
2077 if (unix_peer(sk) != other ||
2078 unix_dgram_peer_wake_me(sk, other)) {
2079 err = -EAGAIN;
2080 sk_locked = 1;
2081 goto out_unlock;
2082 }
2083
2084 if (!sk_locked) {
2085 sk_locked = 1;
2086 goto restart_locked;
2087 }
2088 }
2089
2090 if (unlikely(sk_locked))
2091 unix_state_unlock(sk);
2092
2093 if (sock_flag(other, SOCK_RCVTSTAMP))
2094 __net_timestamp(skb);
2095 maybe_add_creds(skb, sock, other);
2096 scm_stat_add(other, skb);
2097 skb_queue_tail(&other->sk_receive_queue, skb);
2098 unix_state_unlock(other);
2099 other->sk_data_ready(other);
2100 sock_put(other);
2101 scm_destroy(&scm);
2102 return len;
2103
2104out_unlock:
2105 if (sk_locked)
2106 unix_state_unlock(sk);
2107 unix_state_unlock(other);
2108out_free:
2109 kfree_skb(skb);
2110out:
2111 if (other)
2112 sock_put(other);
2113 scm_destroy(&scm);
2114 return err;
2115}
2116
2117/* We use paged skbs for stream sockets, and limit occupancy to 32768
2118 * bytes, and a minimum of a full page.
2119 */
2120#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
2121
2122#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2123static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other,
2124 struct scm_cookie *scm, bool fds_sent)
2125{
2126 struct unix_sock *ousk = unix_sk(other);
2127 struct sk_buff *skb;
2128 int err = 0;
2129
2130 skb = sock_alloc_send_skb(sock->sk, 1, msg->msg_flags & MSG_DONTWAIT, &err);
2131
2132 if (!skb)
2133 return err;
2134
2135 err = unix_scm_to_skb(scm, skb, !fds_sent);
2136 if (err < 0) {
2137 kfree_skb(skb);
2138 return err;
2139 }
2140 skb_put(skb, 1);
2141 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, 1);
2142
2143 if (err) {
2144 kfree_skb(skb);
2145 return err;
2146 }
2147
2148 unix_state_lock(other);
2149
2150 if (sock_flag(other, SOCK_DEAD) ||
2151 (other->sk_shutdown & RCV_SHUTDOWN)) {
2152 unix_state_unlock(other);
2153 kfree_skb(skb);
2154 return -EPIPE;
2155 }
2156
2157 maybe_add_creds(skb, sock, other);
2158 skb_get(skb);
2159
2160 if (ousk->oob_skb)
2161 consume_skb(ousk->oob_skb);
2162
2163 WRITE_ONCE(ousk->oob_skb, skb);
2164
2165 scm_stat_add(other, skb);
2166 skb_queue_tail(&other->sk_receive_queue, skb);
2167 sk_send_sigurg(other);
2168 unix_state_unlock(other);
2169 other->sk_data_ready(other);
2170
2171 return err;
2172}
2173#endif
2174
2175static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
2176 size_t len)
2177{
2178 struct sock *sk = sock->sk;
2179 struct sock *other = NULL;
2180 int err, size;
2181 struct sk_buff *skb;
2182 int sent = 0;
2183 struct scm_cookie scm;
2184 bool fds_sent = false;
2185 int data_len;
2186
2187 wait_for_unix_gc();
2188 err = scm_send(sock, msg, &scm, false);
2189 if (err < 0)
2190 return err;
2191
2192 err = -EOPNOTSUPP;
2193 if (msg->msg_flags & MSG_OOB) {
2194#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2195 if (len)
2196 len--;
2197 else
2198#endif
2199 goto out_err;
2200 }
2201
2202 if (msg->msg_namelen) {
2203 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
2204 goto out_err;
2205 } else {
2206 err = -ENOTCONN;
2207 other = unix_peer(sk);
2208 if (!other)
2209 goto out_err;
2210 }
2211
2212 if (sk->sk_shutdown & SEND_SHUTDOWN)
2213 goto pipe_err;
2214
2215 while (sent < len) {
2216 size = len - sent;
2217
2218 if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {
2219 skb = sock_alloc_send_pskb(sk, 0, 0,
2220 msg->msg_flags & MSG_DONTWAIT,
2221 &err, 0);
2222 } else {
2223 /* Keep two messages in the pipe so it schedules better */
2224 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
2225
2226 /* allow fallback to order-0 allocations */
2227 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
2228
2229 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
2230
2231 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
2232
2233 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
2234 msg->msg_flags & MSG_DONTWAIT, &err,
2235 get_order(UNIX_SKB_FRAGS_SZ));
2236 }
2237 if (!skb)
2238 goto out_err;
2239
2240 /* Only send the fds in the first buffer */
2241 err = unix_scm_to_skb(&scm, skb, !fds_sent);
2242 if (err < 0) {
2243 kfree_skb(skb);
2244 goto out_err;
2245 }
2246 fds_sent = true;
2247
2248 if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {
2249 err = skb_splice_from_iter(skb, &msg->msg_iter, size,
2250 sk->sk_allocation);
2251 if (err < 0) {
2252 kfree_skb(skb);
2253 goto out_err;
2254 }
2255 size = err;
2256 refcount_add(size, &sk->sk_wmem_alloc);
2257 } else {
2258 skb_put(skb, size - data_len);
2259 skb->data_len = data_len;
2260 skb->len = size;
2261 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
2262 if (err) {
2263 kfree_skb(skb);
2264 goto out_err;
2265 }
2266 }
2267
2268 unix_state_lock(other);
2269
2270 if (sock_flag(other, SOCK_DEAD) ||
2271 (other->sk_shutdown & RCV_SHUTDOWN))
2272 goto pipe_err_free;
2273
2274 maybe_add_creds(skb, sock, other);
2275 scm_stat_add(other, skb);
2276 skb_queue_tail(&other->sk_receive_queue, skb);
2277 unix_state_unlock(other);
2278 other->sk_data_ready(other);
2279 sent += size;
2280 }
2281
2282#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2283 if (msg->msg_flags & MSG_OOB) {
2284 err = queue_oob(sock, msg, other, &scm, fds_sent);
2285 if (err)
2286 goto out_err;
2287 sent++;
2288 }
2289#endif
2290
2291 scm_destroy(&scm);
2292
2293 return sent;
2294
2295pipe_err_free:
2296 unix_state_unlock(other);
2297 kfree_skb(skb);
2298pipe_err:
2299 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
2300 send_sig(SIGPIPE, current, 0);
2301 err = -EPIPE;
2302out_err:
2303 scm_destroy(&scm);
2304 return sent ? : err;
2305}
2306
2307static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2308 size_t len)
2309{
2310 int err;
2311 struct sock *sk = sock->sk;
2312
2313 err = sock_error(sk);
2314 if (err)
2315 return err;
2316
2317 if (sk->sk_state != TCP_ESTABLISHED)
2318 return -ENOTCONN;
2319
2320 if (msg->msg_namelen)
2321 msg->msg_namelen = 0;
2322
2323 return unix_dgram_sendmsg(sock, msg, len);
2324}
2325
2326static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2327 size_t size, int flags)
2328{
2329 struct sock *sk = sock->sk;
2330
2331 if (sk->sk_state != TCP_ESTABLISHED)
2332 return -ENOTCONN;
2333
2334 return unix_dgram_recvmsg(sock, msg, size, flags);
2335}
2336
2337static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2338{
2339 struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
2340
2341 if (addr) {
2342 msg->msg_namelen = addr->len;
2343 memcpy(msg->msg_name, addr->name, addr->len);
2344 }
2345}
2346
2347int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size,
2348 int flags)
2349{
2350 struct scm_cookie scm;
2351 struct socket *sock = sk->sk_socket;
2352 struct unix_sock *u = unix_sk(sk);
2353 struct sk_buff *skb, *last;
2354 long timeo;
2355 int skip;
2356 int err;
2357
2358 err = -EOPNOTSUPP;
2359 if (flags&MSG_OOB)
2360 goto out;
2361
2362 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2363
2364 do {
2365 mutex_lock(&u->iolock);
2366
2367 skip = sk_peek_offset(sk, flags);
2368 skb = __skb_try_recv_datagram(sk, &sk->sk_receive_queue, flags,
2369 &skip, &err, &last);
2370 if (skb) {
2371 if (!(flags & MSG_PEEK))
2372 scm_stat_del(sk, skb);
2373 break;
2374 }
2375
2376 mutex_unlock(&u->iolock);
2377
2378 if (err != -EAGAIN)
2379 break;
2380 } while (timeo &&
2381 !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue,
2382 &err, &timeo, last));
2383
2384 if (!skb) { /* implies iolock unlocked */
2385 unix_state_lock(sk);
2386 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2387 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2388 (sk->sk_shutdown & RCV_SHUTDOWN))
2389 err = 0;
2390 unix_state_unlock(sk);
2391 goto out;
2392 }
2393
2394 if (wq_has_sleeper(&u->peer_wait))
2395 wake_up_interruptible_sync_poll(&u->peer_wait,
2396 EPOLLOUT | EPOLLWRNORM |
2397 EPOLLWRBAND);
2398
2399 if (msg->msg_name) {
2400 unix_copy_addr(msg, skb->sk);
2401
2402 BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk,
2403 msg->msg_name,
2404 &msg->msg_namelen);
2405 }
2406
2407 if (size > skb->len - skip)
2408 size = skb->len - skip;
2409 else if (size < skb->len - skip)
2410 msg->msg_flags |= MSG_TRUNC;
2411
2412 err = skb_copy_datagram_msg(skb, skip, msg, size);
2413 if (err)
2414 goto out_free;
2415
2416 if (sock_flag(sk, SOCK_RCVTSTAMP))
2417 __sock_recv_timestamp(msg, sk, skb);
2418
2419 memset(&scm, 0, sizeof(scm));
2420
2421 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2422 unix_set_secdata(&scm, skb);
2423
2424 if (!(flags & MSG_PEEK)) {
2425 if (UNIXCB(skb).fp)
2426 unix_detach_fds(&scm, skb);
2427
2428 sk_peek_offset_bwd(sk, skb->len);
2429 } else {
2430 /* It is questionable: on PEEK we could:
2431 - do not return fds - good, but too simple 8)
2432 - return fds, and do not return them on read (old strategy,
2433 apparently wrong)
2434 - clone fds (I chose it for now, it is the most universal
2435 solution)
2436
2437 POSIX 1003.1g does not actually define this clearly
2438 at all. POSIX 1003.1g doesn't define a lot of things
2439 clearly however!
2440
2441 */
2442
2443 sk_peek_offset_fwd(sk, size);
2444
2445 if (UNIXCB(skb).fp)
2446 unix_peek_fds(&scm, skb);
2447 }
2448 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2449
2450 scm_recv_unix(sock, msg, &scm, flags);
2451
2452out_free:
2453 skb_free_datagram(sk, skb);
2454 mutex_unlock(&u->iolock);
2455out:
2456 return err;
2457}
2458
2459static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
2460 int flags)
2461{
2462 struct sock *sk = sock->sk;
2463
2464#ifdef CONFIG_BPF_SYSCALL
2465 const struct proto *prot = READ_ONCE(sk->sk_prot);
2466
2467 if (prot != &unix_dgram_proto)
2468 return prot->recvmsg(sk, msg, size, flags, NULL);
2469#endif
2470 return __unix_dgram_recvmsg(sk, msg, size, flags);
2471}
2472
2473static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
2474{
2475 struct unix_sock *u = unix_sk(sk);
2476 struct sk_buff *skb;
2477 int err;
2478
2479 mutex_lock(&u->iolock);
2480 skb = skb_recv_datagram(sk, MSG_DONTWAIT, &err);
2481 mutex_unlock(&u->iolock);
2482 if (!skb)
2483 return err;
2484
2485 return recv_actor(sk, skb);
2486}
2487
2488/*
2489 * Sleep until more data has arrived. But check for races..
2490 */
2491static long unix_stream_data_wait(struct sock *sk, long timeo,
2492 struct sk_buff *last, unsigned int last_len,
2493 bool freezable)
2494{
2495 unsigned int state = TASK_INTERRUPTIBLE | freezable * TASK_FREEZABLE;
2496 struct sk_buff *tail;
2497 DEFINE_WAIT(wait);
2498
2499 unix_state_lock(sk);
2500
2501 for (;;) {
2502 prepare_to_wait(sk_sleep(sk), &wait, state);
2503
2504 tail = skb_peek_tail(&sk->sk_receive_queue);
2505 if (tail != last ||
2506 (tail && tail->len != last_len) ||
2507 sk->sk_err ||
2508 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2509 signal_pending(current) ||
2510 !timeo)
2511 break;
2512
2513 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2514 unix_state_unlock(sk);
2515 timeo = schedule_timeout(timeo);
2516 unix_state_lock(sk);
2517
2518 if (sock_flag(sk, SOCK_DEAD))
2519 break;
2520
2521 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2522 }
2523
2524 finish_wait(sk_sleep(sk), &wait);
2525 unix_state_unlock(sk);
2526 return timeo;
2527}
2528
2529static unsigned int unix_skb_len(const struct sk_buff *skb)
2530{
2531 return skb->len - UNIXCB(skb).consumed;
2532}
2533
2534struct unix_stream_read_state {
2535 int (*recv_actor)(struct sk_buff *, int, int,
2536 struct unix_stream_read_state *);
2537 struct socket *socket;
2538 struct msghdr *msg;
2539 struct pipe_inode_info *pipe;
2540 size_t size;
2541 int flags;
2542 unsigned int splice_flags;
2543};
2544
2545#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2546static int unix_stream_recv_urg(struct unix_stream_read_state *state)
2547{
2548 struct socket *sock = state->socket;
2549 struct sock *sk = sock->sk;
2550 struct unix_sock *u = unix_sk(sk);
2551 int chunk = 1;
2552 struct sk_buff *oob_skb;
2553
2554 mutex_lock(&u->iolock);
2555 unix_state_lock(sk);
2556
2557 if (sock_flag(sk, SOCK_URGINLINE) || !u->oob_skb) {
2558 unix_state_unlock(sk);
2559 mutex_unlock(&u->iolock);
2560 return -EINVAL;
2561 }
2562
2563 oob_skb = u->oob_skb;
2564
2565 if (!(state->flags & MSG_PEEK))
2566 WRITE_ONCE(u->oob_skb, NULL);
2567 else
2568 skb_get(oob_skb);
2569 unix_state_unlock(sk);
2570
2571 chunk = state->recv_actor(oob_skb, 0, chunk, state);
2572
2573 if (!(state->flags & MSG_PEEK))
2574 UNIXCB(oob_skb).consumed += 1;
2575
2576 consume_skb(oob_skb);
2577
2578 mutex_unlock(&u->iolock);
2579
2580 if (chunk < 0)
2581 return -EFAULT;
2582
2583 state->msg->msg_flags |= MSG_OOB;
2584 return 1;
2585}
2586
2587static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
2588 int flags, int copied)
2589{
2590 struct unix_sock *u = unix_sk(sk);
2591
2592 if (!unix_skb_len(skb) && !(flags & MSG_PEEK)) {
2593 skb_unlink(skb, &sk->sk_receive_queue);
2594 consume_skb(skb);
2595 skb = NULL;
2596 } else {
2597 if (skb == u->oob_skb) {
2598 if (copied) {
2599 skb = NULL;
2600 } else if (sock_flag(sk, SOCK_URGINLINE)) {
2601 if (!(flags & MSG_PEEK)) {
2602 WRITE_ONCE(u->oob_skb, NULL);
2603 consume_skb(skb);
2604 }
2605 } else if (!(flags & MSG_PEEK)) {
2606 skb_unlink(skb, &sk->sk_receive_queue);
2607 consume_skb(skb);
2608 skb = skb_peek(&sk->sk_receive_queue);
2609 }
2610 }
2611 }
2612 return skb;
2613}
2614#endif
2615
2616static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
2617{
2618 if (unlikely(sk->sk_state != TCP_ESTABLISHED))
2619 return -ENOTCONN;
2620
2621 return unix_read_skb(sk, recv_actor);
2622}
2623
2624static int unix_stream_read_generic(struct unix_stream_read_state *state,
2625 bool freezable)
2626{
2627 struct scm_cookie scm;
2628 struct socket *sock = state->socket;
2629 struct sock *sk = sock->sk;
2630 struct unix_sock *u = unix_sk(sk);
2631 int copied = 0;
2632 int flags = state->flags;
2633 int noblock = flags & MSG_DONTWAIT;
2634 bool check_creds = false;
2635 int target;
2636 int err = 0;
2637 long timeo;
2638 int skip;
2639 size_t size = state->size;
2640 unsigned int last_len;
2641
2642 if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
2643 err = -EINVAL;
2644 goto out;
2645 }
2646
2647 if (unlikely(flags & MSG_OOB)) {
2648 err = -EOPNOTSUPP;
2649#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2650 err = unix_stream_recv_urg(state);
2651#endif
2652 goto out;
2653 }
2654
2655 target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2656 timeo = sock_rcvtimeo(sk, noblock);
2657
2658 memset(&scm, 0, sizeof(scm));
2659
2660 /* Lock the socket to prevent queue disordering
2661 * while sleeps in memcpy_tomsg
2662 */
2663 mutex_lock(&u->iolock);
2664
2665 skip = max(sk_peek_offset(sk, flags), 0);
2666
2667 do {
2668 int chunk;
2669 bool drop_skb;
2670 struct sk_buff *skb, *last;
2671
2672redo:
2673 unix_state_lock(sk);
2674 if (sock_flag(sk, SOCK_DEAD)) {
2675 err = -ECONNRESET;
2676 goto unlock;
2677 }
2678 last = skb = skb_peek(&sk->sk_receive_queue);
2679 last_len = last ? last->len : 0;
2680
2681#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
2682 if (skb) {
2683 skb = manage_oob(skb, sk, flags, copied);
2684 if (!skb) {
2685 unix_state_unlock(sk);
2686 if (copied)
2687 break;
2688 goto redo;
2689 }
2690 }
2691#endif
2692again:
2693 if (skb == NULL) {
2694 if (copied >= target)
2695 goto unlock;
2696
2697 /*
2698 * POSIX 1003.1g mandates this order.
2699 */
2700
2701 err = sock_error(sk);
2702 if (err)
2703 goto unlock;
2704 if (sk->sk_shutdown & RCV_SHUTDOWN)
2705 goto unlock;
2706
2707 unix_state_unlock(sk);
2708 if (!timeo) {
2709 err = -EAGAIN;
2710 break;
2711 }
2712
2713 mutex_unlock(&u->iolock);
2714
2715 timeo = unix_stream_data_wait(sk, timeo, last,
2716 last_len, freezable);
2717
2718 if (signal_pending(current)) {
2719 err = sock_intr_errno(timeo);
2720 scm_destroy(&scm);
2721 goto out;
2722 }
2723
2724 mutex_lock(&u->iolock);
2725 goto redo;
2726unlock:
2727 unix_state_unlock(sk);
2728 break;
2729 }
2730
2731 while (skip >= unix_skb_len(skb)) {
2732 skip -= unix_skb_len(skb);
2733 last = skb;
2734 last_len = skb->len;
2735 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2736 if (!skb)
2737 goto again;
2738 }
2739
2740 unix_state_unlock(sk);
2741
2742 if (check_creds) {
2743 /* Never glue messages from different writers */
2744 if (!unix_skb_scm_eq(skb, &scm))
2745 break;
2746 } else if (test_bit(SOCK_PASSCRED, &sock->flags) ||
2747 test_bit(SOCK_PASSPIDFD, &sock->flags)) {
2748 /* Copy credentials */
2749 scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2750 unix_set_secdata(&scm, skb);
2751 check_creds = true;
2752 }
2753
2754 /* Copy address just once */
2755 if (state->msg && state->msg->msg_name) {
2756 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2757 state->msg->msg_name);
2758 unix_copy_addr(state->msg, skb->sk);
2759
2760 BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk,
2761 state->msg->msg_name,
2762 &state->msg->msg_namelen);
2763
2764 sunaddr = NULL;
2765 }
2766
2767 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2768 skb_get(skb);
2769 chunk = state->recv_actor(skb, skip, chunk, state);
2770 drop_skb = !unix_skb_len(skb);
2771 /* skb is only safe to use if !drop_skb */
2772 consume_skb(skb);
2773 if (chunk < 0) {
2774 if (copied == 0)
2775 copied = -EFAULT;
2776 break;
2777 }
2778 copied += chunk;
2779 size -= chunk;
2780
2781 if (drop_skb) {
2782 /* the skb was touched by a concurrent reader;
2783 * we should not expect anything from this skb
2784 * anymore and assume it invalid - we can be
2785 * sure it was dropped from the socket queue
2786 *
2787 * let's report a short read
2788 */
2789 err = 0;
2790 break;
2791 }
2792
2793 /* Mark read part of skb as used */
2794 if (!(flags & MSG_PEEK)) {
2795 UNIXCB(skb).consumed += chunk;
2796
2797 sk_peek_offset_bwd(sk, chunk);
2798
2799 if (UNIXCB(skb).fp) {
2800 scm_stat_del(sk, skb);
2801 unix_detach_fds(&scm, skb);
2802 }
2803
2804 if (unix_skb_len(skb))
2805 break;
2806
2807 skb_unlink(skb, &sk->sk_receive_queue);
2808 consume_skb(skb);
2809
2810 if (scm.fp)
2811 break;
2812 } else {
2813 /* It is questionable, see note in unix_dgram_recvmsg.
2814 */
2815 if (UNIXCB(skb).fp)
2816 unix_peek_fds(&scm, skb);
2817
2818 sk_peek_offset_fwd(sk, chunk);
2819
2820 if (UNIXCB(skb).fp)
2821 break;
2822
2823 skip = 0;
2824 last = skb;
2825 last_len = skb->len;
2826 unix_state_lock(sk);
2827 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2828 if (skb)
2829 goto again;
2830 unix_state_unlock(sk);
2831 break;
2832 }
2833 } while (size);
2834
2835 mutex_unlock(&u->iolock);
2836 if (state->msg)
2837 scm_recv_unix(sock, state->msg, &scm, flags);
2838 else
2839 scm_destroy(&scm);
2840out:
2841 return copied ? : err;
2842}
2843
2844static int unix_stream_read_actor(struct sk_buff *skb,
2845 int skip, int chunk,
2846 struct unix_stream_read_state *state)
2847{
2848 int ret;
2849
2850 ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2851 state->msg, chunk);
2852 return ret ?: chunk;
2853}
2854
2855int __unix_stream_recvmsg(struct sock *sk, struct msghdr *msg,
2856 size_t size, int flags)
2857{
2858 struct unix_stream_read_state state = {
2859 .recv_actor = unix_stream_read_actor,
2860 .socket = sk->sk_socket,
2861 .msg = msg,
2862 .size = size,
2863 .flags = flags
2864 };
2865
2866 return unix_stream_read_generic(&state, true);
2867}
2868
2869static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2870 size_t size, int flags)
2871{
2872 struct unix_stream_read_state state = {
2873 .recv_actor = unix_stream_read_actor,
2874 .socket = sock,
2875 .msg = msg,
2876 .size = size,
2877 .flags = flags
2878 };
2879
2880#ifdef CONFIG_BPF_SYSCALL
2881 struct sock *sk = sock->sk;
2882 const struct proto *prot = READ_ONCE(sk->sk_prot);
2883
2884 if (prot != &unix_stream_proto)
2885 return prot->recvmsg(sk, msg, size, flags, NULL);
2886#endif
2887 return unix_stream_read_generic(&state, true);
2888}
2889
2890static int unix_stream_splice_actor(struct sk_buff *skb,
2891 int skip, int chunk,
2892 struct unix_stream_read_state *state)
2893{
2894 return skb_splice_bits(skb, state->socket->sk,
2895 UNIXCB(skb).consumed + skip,
2896 state->pipe, chunk, state->splice_flags);
2897}
2898
2899static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos,
2900 struct pipe_inode_info *pipe,
2901 size_t size, unsigned int flags)
2902{
2903 struct unix_stream_read_state state = {
2904 .recv_actor = unix_stream_splice_actor,
2905 .socket = sock,
2906 .pipe = pipe,
2907 .size = size,
2908 .splice_flags = flags,
2909 };
2910
2911 if (unlikely(*ppos))
2912 return -ESPIPE;
2913
2914 if (sock->file->f_flags & O_NONBLOCK ||
2915 flags & SPLICE_F_NONBLOCK)
2916 state.flags = MSG_DONTWAIT;
2917
2918 return unix_stream_read_generic(&state, false);
2919}
2920
2921static int unix_shutdown(struct socket *sock, int mode)
2922{
2923 struct sock *sk = sock->sk;
2924 struct sock *other;
2925
2926 if (mode < SHUT_RD || mode > SHUT_RDWR)
2927 return -EINVAL;
2928 /* This maps:
2929 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2930 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2931 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2932 */
2933 ++mode;
2934
2935 unix_state_lock(sk);
2936 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | mode);
2937 other = unix_peer(sk);
2938 if (other)
2939 sock_hold(other);
2940 unix_state_unlock(sk);
2941 sk->sk_state_change(sk);
2942
2943 if (other &&
2944 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2945
2946 int peer_mode = 0;
2947 const struct proto *prot = READ_ONCE(other->sk_prot);
2948
2949 if (prot->unhash)
2950 prot->unhash(other);
2951 if (mode&RCV_SHUTDOWN)
2952 peer_mode |= SEND_SHUTDOWN;
2953 if (mode&SEND_SHUTDOWN)
2954 peer_mode |= RCV_SHUTDOWN;
2955 unix_state_lock(other);
2956 WRITE_ONCE(other->sk_shutdown, other->sk_shutdown | peer_mode);
2957 unix_state_unlock(other);
2958 other->sk_state_change(other);
2959 if (peer_mode == SHUTDOWN_MASK)
2960 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2961 else if (peer_mode & RCV_SHUTDOWN)
2962 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2963 }
2964 if (other)
2965 sock_put(other);
2966
2967 return 0;
2968}
2969
2970long unix_inq_len(struct sock *sk)
2971{
2972 struct sk_buff *skb;
2973 long amount = 0;
2974
2975 if (sk->sk_state == TCP_LISTEN)
2976 return -EINVAL;
2977
2978 spin_lock(&sk->sk_receive_queue.lock);
2979 if (sk->sk_type == SOCK_STREAM ||
2980 sk->sk_type == SOCK_SEQPACKET) {
2981 skb_queue_walk(&sk->sk_receive_queue, skb)
2982 amount += unix_skb_len(skb);
2983 } else {
2984 skb = skb_peek(&sk->sk_receive_queue);
2985 if (skb)
2986 amount = skb->len;
2987 }
2988 spin_unlock(&sk->sk_receive_queue.lock);
2989
2990 return amount;
2991}
2992EXPORT_SYMBOL_GPL(unix_inq_len);
2993
2994long unix_outq_len(struct sock *sk)
2995{
2996 return sk_wmem_alloc_get(sk);
2997}
2998EXPORT_SYMBOL_GPL(unix_outq_len);
2999
3000static int unix_open_file(struct sock *sk)
3001{
3002 struct path path;
3003 struct file *f;
3004 int fd;
3005
3006 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
3007 return -EPERM;
3008
3009 if (!smp_load_acquire(&unix_sk(sk)->addr))
3010 return -ENOENT;
3011
3012 path = unix_sk(sk)->path;
3013 if (!path.dentry)
3014 return -ENOENT;
3015
3016 path_get(&path);
3017
3018 fd = get_unused_fd_flags(O_CLOEXEC);
3019 if (fd < 0)
3020 goto out;
3021
3022 f = dentry_open(&path, O_PATH, current_cred());
3023 if (IS_ERR(f)) {
3024 put_unused_fd(fd);
3025 fd = PTR_ERR(f);
3026 goto out;
3027 }
3028
3029 fd_install(fd, f);
3030out:
3031 path_put(&path);
3032
3033 return fd;
3034}
3035
3036static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
3037{
3038 struct sock *sk = sock->sk;
3039 long amount = 0;
3040 int err;
3041
3042 switch (cmd) {
3043 case SIOCOUTQ:
3044 amount = unix_outq_len(sk);
3045 err = put_user(amount, (int __user *)arg);
3046 break;
3047 case SIOCINQ:
3048 amount = unix_inq_len(sk);
3049 if (amount < 0)
3050 err = amount;
3051 else
3052 err = put_user(amount, (int __user *)arg);
3053 break;
3054 case SIOCUNIXFILE:
3055 err = unix_open_file(sk);
3056 break;
3057#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
3058 case SIOCATMARK:
3059 {
3060 struct sk_buff *skb;
3061 int answ = 0;
3062
3063 skb = skb_peek(&sk->sk_receive_queue);
3064 if (skb && skb == READ_ONCE(unix_sk(sk)->oob_skb))
3065 answ = 1;
3066 err = put_user(answ, (int __user *)arg);
3067 }
3068 break;
3069#endif
3070 default:
3071 err = -ENOIOCTLCMD;
3072 break;
3073 }
3074 return err;
3075}
3076
3077#ifdef CONFIG_COMPAT
3078static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
3079{
3080 return unix_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
3081}
3082#endif
3083
3084static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait)
3085{
3086 struct sock *sk = sock->sk;
3087 __poll_t mask;
3088 u8 shutdown;
3089
3090 sock_poll_wait(file, sock, wait);
3091 mask = 0;
3092 shutdown = READ_ONCE(sk->sk_shutdown);
3093
3094 /* exceptional events? */
3095 if (READ_ONCE(sk->sk_err))
3096 mask |= EPOLLERR;
3097 if (shutdown == SHUTDOWN_MASK)
3098 mask |= EPOLLHUP;
3099 if (shutdown & RCV_SHUTDOWN)
3100 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
3101
3102 /* readable? */
3103 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
3104 mask |= EPOLLIN | EPOLLRDNORM;
3105 if (sk_is_readable(sk))
3106 mask |= EPOLLIN | EPOLLRDNORM;
3107#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
3108 if (READ_ONCE(unix_sk(sk)->oob_skb))
3109 mask |= EPOLLPRI;
3110#endif
3111
3112 /* Connection-based need to check for termination and startup */
3113 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
3114 sk->sk_state == TCP_CLOSE)
3115 mask |= EPOLLHUP;
3116
3117 /*
3118 * we set writable also when the other side has shut down the
3119 * connection. This prevents stuck sockets.
3120 */
3121 if (unix_writable(sk))
3122 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
3123
3124 return mask;
3125}
3126
3127static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
3128 poll_table *wait)
3129{
3130 struct sock *sk = sock->sk, *other;
3131 unsigned int writable;
3132 __poll_t mask;
3133 u8 shutdown;
3134
3135 sock_poll_wait(file, sock, wait);
3136 mask = 0;
3137 shutdown = READ_ONCE(sk->sk_shutdown);
3138
3139 /* exceptional events? */
3140 if (READ_ONCE(sk->sk_err) ||
3141 !skb_queue_empty_lockless(&sk->sk_error_queue))
3142 mask |= EPOLLERR |
3143 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
3144
3145 if (shutdown & RCV_SHUTDOWN)
3146 mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
3147 if (shutdown == SHUTDOWN_MASK)
3148 mask |= EPOLLHUP;
3149
3150 /* readable? */
3151 if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
3152 mask |= EPOLLIN | EPOLLRDNORM;
3153 if (sk_is_readable(sk))
3154 mask |= EPOLLIN | EPOLLRDNORM;
3155
3156 /* Connection-based need to check for termination and startup */
3157 if (sk->sk_type == SOCK_SEQPACKET) {
3158 if (sk->sk_state == TCP_CLOSE)
3159 mask |= EPOLLHUP;
3160 /* connection hasn't started yet? */
3161 if (sk->sk_state == TCP_SYN_SENT)
3162 return mask;
3163 }
3164
3165 /* No write status requested, avoid expensive OUT tests. */
3166 if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT)))
3167 return mask;
3168
3169 writable = unix_writable(sk);
3170 if (writable) {
3171 unix_state_lock(sk);
3172
3173 other = unix_peer(sk);
3174 if (other && unix_peer(other) != sk &&
3175 unix_recvq_full_lockless(other) &&
3176 unix_dgram_peer_wake_me(sk, other))
3177 writable = 0;
3178
3179 unix_state_unlock(sk);
3180 }
3181
3182 if (writable)
3183 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
3184 else
3185 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
3186
3187 return mask;
3188}
3189
3190#ifdef CONFIG_PROC_FS
3191
3192#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
3193
3194#define get_bucket(x) ((x) >> BUCKET_SPACE)
3195#define get_offset(x) ((x) & ((1UL << BUCKET_SPACE) - 1))
3196#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
3197
3198static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
3199{
3200 unsigned long offset = get_offset(*pos);
3201 unsigned long bucket = get_bucket(*pos);
3202 unsigned long count = 0;
3203 struct sock *sk;
3204
3205 for (sk = sk_head(&seq_file_net(seq)->unx.table.buckets[bucket]);
3206 sk; sk = sk_next(sk)) {
3207 if (++count == offset)
3208 break;
3209 }
3210
3211 return sk;
3212}
3213
3214static struct sock *unix_get_first(struct seq_file *seq, loff_t *pos)
3215{
3216 unsigned long bucket = get_bucket(*pos);
3217 struct net *net = seq_file_net(seq);
3218 struct sock *sk;
3219
3220 while (bucket < UNIX_HASH_SIZE) {
3221 spin_lock(&net->unx.table.locks[bucket]);
3222
3223 sk = unix_from_bucket(seq, pos);
3224 if (sk)
3225 return sk;
3226
3227 spin_unlock(&net->unx.table.locks[bucket]);
3228
3229 *pos = set_bucket_offset(++bucket, 1);
3230 }
3231
3232 return NULL;
3233}
3234
3235static struct sock *unix_get_next(struct seq_file *seq, struct sock *sk,
3236 loff_t *pos)
3237{
3238 unsigned long bucket = get_bucket(*pos);
3239
3240 sk = sk_next(sk);
3241 if (sk)
3242 return sk;
3243
3244
3245 spin_unlock(&seq_file_net(seq)->unx.table.locks[bucket]);
3246
3247 *pos = set_bucket_offset(++bucket, 1);
3248
3249 return unix_get_first(seq, pos);
3250}
3251
3252static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
3253{
3254 if (!*pos)
3255 return SEQ_START_TOKEN;
3256
3257 return unix_get_first(seq, pos);
3258}
3259
3260static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3261{
3262 ++*pos;
3263
3264 if (v == SEQ_START_TOKEN)
3265 return unix_get_first(seq, pos);
3266
3267 return unix_get_next(seq, v, pos);
3268}
3269
3270static void unix_seq_stop(struct seq_file *seq, void *v)
3271{
3272 struct sock *sk = v;
3273
3274 if (sk)
3275 spin_unlock(&seq_file_net(seq)->unx.table.locks[sk->sk_hash]);
3276}
3277
3278static int unix_seq_show(struct seq_file *seq, void *v)
3279{
3280
3281 if (v == SEQ_START_TOKEN)
3282 seq_puts(seq, "Num RefCount Protocol Flags Type St "
3283 "Inode Path\n");
3284 else {
3285 struct sock *s = v;
3286 struct unix_sock *u = unix_sk(s);
3287 unix_state_lock(s);
3288
3289 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
3290 s,
3291 refcount_read(&s->sk_refcnt),
3292 0,
3293 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
3294 s->sk_type,
3295 s->sk_socket ?
3296 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
3297 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
3298 sock_i_ino(s));
3299
3300 if (u->addr) { // under a hash table lock here
3301 int i, len;
3302 seq_putc(seq, ' ');
3303
3304 i = 0;
3305 len = u->addr->len -
3306 offsetof(struct sockaddr_un, sun_path);
3307 if (u->addr->name->sun_path[0]) {
3308 len--;
3309 } else {
3310 seq_putc(seq, '@');
3311 i++;
3312 }
3313 for ( ; i < len; i++)
3314 seq_putc(seq, u->addr->name->sun_path[i] ?:
3315 '@');
3316 }
3317 unix_state_unlock(s);
3318 seq_putc(seq, '\n');
3319 }
3320
3321 return 0;
3322}
3323
3324static const struct seq_operations unix_seq_ops = {
3325 .start = unix_seq_start,
3326 .next = unix_seq_next,
3327 .stop = unix_seq_stop,
3328 .show = unix_seq_show,
3329};
3330
3331#ifdef CONFIG_BPF_SYSCALL
3332struct bpf_unix_iter_state {
3333 struct seq_net_private p;
3334 unsigned int cur_sk;
3335 unsigned int end_sk;
3336 unsigned int max_sk;
3337 struct sock **batch;
3338 bool st_bucket_done;
3339};
3340
3341struct bpf_iter__unix {
3342 __bpf_md_ptr(struct bpf_iter_meta *, meta);
3343 __bpf_md_ptr(struct unix_sock *, unix_sk);
3344 uid_t uid __aligned(8);
3345};
3346
3347static int unix_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
3348 struct unix_sock *unix_sk, uid_t uid)
3349{
3350 struct bpf_iter__unix ctx;
3351
3352 meta->seq_num--; /* skip SEQ_START_TOKEN */
3353 ctx.meta = meta;
3354 ctx.unix_sk = unix_sk;
3355 ctx.uid = uid;
3356 return bpf_iter_run_prog(prog, &ctx);
3357}
3358
3359static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk)
3360
3361{
3362 struct bpf_unix_iter_state *iter = seq->private;
3363 unsigned int expected = 1;
3364 struct sock *sk;
3365
3366 sock_hold(start_sk);
3367 iter->batch[iter->end_sk++] = start_sk;
3368
3369 for (sk = sk_next(start_sk); sk; sk = sk_next(sk)) {
3370 if (iter->end_sk < iter->max_sk) {
3371 sock_hold(sk);
3372 iter->batch[iter->end_sk++] = sk;
3373 }
3374
3375 expected++;
3376 }
3377
3378 spin_unlock(&seq_file_net(seq)->unx.table.locks[start_sk->sk_hash]);
3379
3380 return expected;
3381}
3382
3383static void bpf_iter_unix_put_batch(struct bpf_unix_iter_state *iter)
3384{
3385 while (iter->cur_sk < iter->end_sk)
3386 sock_put(iter->batch[iter->cur_sk++]);
3387}
3388
3389static int bpf_iter_unix_realloc_batch(struct bpf_unix_iter_state *iter,
3390 unsigned int new_batch_sz)
3391{
3392 struct sock **new_batch;
3393
3394 new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz,
3395 GFP_USER | __GFP_NOWARN);
3396 if (!new_batch)
3397 return -ENOMEM;
3398
3399 bpf_iter_unix_put_batch(iter);
3400 kvfree(iter->batch);
3401 iter->batch = new_batch;
3402 iter->max_sk = new_batch_sz;
3403
3404 return 0;
3405}
3406
3407static struct sock *bpf_iter_unix_batch(struct seq_file *seq,
3408 loff_t *pos)
3409{
3410 struct bpf_unix_iter_state *iter = seq->private;
3411 unsigned int expected;
3412 bool resized = false;
3413 struct sock *sk;
3414
3415 if (iter->st_bucket_done)
3416 *pos = set_bucket_offset(get_bucket(*pos) + 1, 1);
3417
3418again:
3419 /* Get a new batch */
3420 iter->cur_sk = 0;
3421 iter->end_sk = 0;
3422
3423 sk = unix_get_first(seq, pos);
3424 if (!sk)
3425 return NULL; /* Done */
3426
3427 expected = bpf_iter_unix_hold_batch(seq, sk);
3428
3429 if (iter->end_sk == expected) {
3430 iter->st_bucket_done = true;
3431 return sk;
3432 }
3433
3434 if (!resized && !bpf_iter_unix_realloc_batch(iter, expected * 3 / 2)) {
3435 resized = true;
3436 goto again;
3437 }
3438
3439 return sk;
3440}
3441
3442static void *bpf_iter_unix_seq_start(struct seq_file *seq, loff_t *pos)
3443{
3444 if (!*pos)
3445 return SEQ_START_TOKEN;
3446
3447 /* bpf iter does not support lseek, so it always
3448 * continue from where it was stop()-ped.
3449 */
3450 return bpf_iter_unix_batch(seq, pos);
3451}
3452
3453static void *bpf_iter_unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3454{
3455 struct bpf_unix_iter_state *iter = seq->private;
3456 struct sock *sk;
3457
3458 /* Whenever seq_next() is called, the iter->cur_sk is
3459 * done with seq_show(), so advance to the next sk in
3460 * the batch.
3461 */
3462 if (iter->cur_sk < iter->end_sk)
3463 sock_put(iter->batch[iter->cur_sk++]);
3464
3465 ++*pos;
3466
3467 if (iter->cur_sk < iter->end_sk)
3468 sk = iter->batch[iter->cur_sk];
3469 else
3470 sk = bpf_iter_unix_batch(seq, pos);
3471
3472 return sk;
3473}
3474
3475static int bpf_iter_unix_seq_show(struct seq_file *seq, void *v)
3476{
3477 struct bpf_iter_meta meta;
3478 struct bpf_prog *prog;
3479 struct sock *sk = v;
3480 uid_t uid;
3481 bool slow;
3482 int ret;
3483
3484 if (v == SEQ_START_TOKEN)
3485 return 0;
3486
3487 slow = lock_sock_fast(sk);
3488
3489 if (unlikely(sk_unhashed(sk))) {
3490 ret = SEQ_SKIP;
3491 goto unlock;
3492 }
3493
3494 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3495 meta.seq = seq;
3496 prog = bpf_iter_get_info(&meta, false);
3497 ret = unix_prog_seq_show(prog, &meta, v, uid);
3498unlock:
3499 unlock_sock_fast(sk, slow);
3500 return ret;
3501}
3502
3503static void bpf_iter_unix_seq_stop(struct seq_file *seq, void *v)
3504{
3505 struct bpf_unix_iter_state *iter = seq->private;
3506 struct bpf_iter_meta meta;
3507 struct bpf_prog *prog;
3508
3509 if (!v) {
3510 meta.seq = seq;
3511 prog = bpf_iter_get_info(&meta, true);
3512 if (prog)
3513 (void)unix_prog_seq_show(prog, &meta, v, 0);
3514 }
3515
3516 if (iter->cur_sk < iter->end_sk)
3517 bpf_iter_unix_put_batch(iter);
3518}
3519
3520static const struct seq_operations bpf_iter_unix_seq_ops = {
3521 .start = bpf_iter_unix_seq_start,
3522 .next = bpf_iter_unix_seq_next,
3523 .stop = bpf_iter_unix_seq_stop,
3524 .show = bpf_iter_unix_seq_show,
3525};
3526#endif
3527#endif
3528
3529static const struct net_proto_family unix_family_ops = {
3530 .family = PF_UNIX,
3531 .create = unix_create,
3532 .owner = THIS_MODULE,
3533};
3534
3535
3536static int __net_init unix_net_init(struct net *net)
3537{
3538 int i;
3539
3540 net->unx.sysctl_max_dgram_qlen = 10;
3541 if (unix_sysctl_register(net))
3542 goto out;
3543
3544#ifdef CONFIG_PROC_FS
3545 if (!proc_create_net("unix", 0, net->proc_net, &unix_seq_ops,
3546 sizeof(struct seq_net_private)))
3547 goto err_sysctl;
3548#endif
3549
3550 net->unx.table.locks = kvmalloc_array(UNIX_HASH_SIZE,
3551 sizeof(spinlock_t), GFP_KERNEL);
3552 if (!net->unx.table.locks)
3553 goto err_proc;
3554
3555 net->unx.table.buckets = kvmalloc_array(UNIX_HASH_SIZE,
3556 sizeof(struct hlist_head),
3557 GFP_KERNEL);
3558 if (!net->unx.table.buckets)
3559 goto free_locks;
3560
3561 for (i = 0; i < UNIX_HASH_SIZE; i++) {
3562 spin_lock_init(&net->unx.table.locks[i]);
3563 INIT_HLIST_HEAD(&net->unx.table.buckets[i]);
3564 }
3565
3566 return 0;
3567
3568free_locks:
3569 kvfree(net->unx.table.locks);
3570err_proc:
3571#ifdef CONFIG_PROC_FS
3572 remove_proc_entry("unix", net->proc_net);
3573err_sysctl:
3574#endif
3575 unix_sysctl_unregister(net);
3576out:
3577 return -ENOMEM;
3578}
3579
3580static void __net_exit unix_net_exit(struct net *net)
3581{
3582 kvfree(net->unx.table.buckets);
3583 kvfree(net->unx.table.locks);
3584 unix_sysctl_unregister(net);
3585 remove_proc_entry("unix", net->proc_net);
3586}
3587
3588static struct pernet_operations unix_net_ops = {
3589 .init = unix_net_init,
3590 .exit = unix_net_exit,
3591};
3592
3593#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3594DEFINE_BPF_ITER_FUNC(unix, struct bpf_iter_meta *meta,
3595 struct unix_sock *unix_sk, uid_t uid)
3596
3597#define INIT_BATCH_SZ 16
3598
3599static int bpf_iter_init_unix(void *priv_data, struct bpf_iter_aux_info *aux)
3600{
3601 struct bpf_unix_iter_state *iter = priv_data;
3602 int err;
3603
3604 err = bpf_iter_init_seq_net(priv_data, aux);
3605 if (err)
3606 return err;
3607
3608 err = bpf_iter_unix_realloc_batch(iter, INIT_BATCH_SZ);
3609 if (err) {
3610 bpf_iter_fini_seq_net(priv_data);
3611 return err;
3612 }
3613
3614 return 0;
3615}
3616
3617static void bpf_iter_fini_unix(void *priv_data)
3618{
3619 struct bpf_unix_iter_state *iter = priv_data;
3620
3621 bpf_iter_fini_seq_net(priv_data);
3622 kvfree(iter->batch);
3623}
3624
3625static const struct bpf_iter_seq_info unix_seq_info = {
3626 .seq_ops = &bpf_iter_unix_seq_ops,
3627 .init_seq_private = bpf_iter_init_unix,
3628 .fini_seq_private = bpf_iter_fini_unix,
3629 .seq_priv_size = sizeof(struct bpf_unix_iter_state),
3630};
3631
3632static const struct bpf_func_proto *
3633bpf_iter_unix_get_func_proto(enum bpf_func_id func_id,
3634 const struct bpf_prog *prog)
3635{
3636 switch (func_id) {
3637 case BPF_FUNC_setsockopt:
3638 return &bpf_sk_setsockopt_proto;
3639 case BPF_FUNC_getsockopt:
3640 return &bpf_sk_getsockopt_proto;
3641 default:
3642 return NULL;
3643 }
3644}
3645
3646static struct bpf_iter_reg unix_reg_info = {
3647 .target = "unix",
3648 .ctx_arg_info_size = 1,
3649 .ctx_arg_info = {
3650 { offsetof(struct bpf_iter__unix, unix_sk),
3651 PTR_TO_BTF_ID_OR_NULL },
3652 },
3653 .get_func_proto = bpf_iter_unix_get_func_proto,
3654 .seq_info = &unix_seq_info,
3655};
3656
3657static void __init bpf_iter_register(void)
3658{
3659 unix_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UNIX];
3660 if (bpf_iter_reg_target(&unix_reg_info))
3661 pr_warn("Warning: could not register bpf iterator unix\n");
3662}
3663#endif
3664
3665static int __init af_unix_init(void)
3666{
3667 int i, rc = -1;
3668
3669 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb));
3670
3671 for (i = 0; i < UNIX_HASH_SIZE / 2; i++) {
3672 spin_lock_init(&bsd_socket_locks[i]);
3673 INIT_HLIST_HEAD(&bsd_socket_buckets[i]);
3674 }
3675
3676 rc = proto_register(&unix_dgram_proto, 1);
3677 if (rc != 0) {
3678 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
3679 goto out;
3680 }
3681
3682 rc = proto_register(&unix_stream_proto, 1);
3683 if (rc != 0) {
3684 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
3685 proto_unregister(&unix_dgram_proto);
3686 goto out;
3687 }
3688
3689 sock_register(&unix_family_ops);
3690 register_pernet_subsys(&unix_net_ops);
3691 unix_bpf_build_proto();
3692
3693#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3694 bpf_iter_register();
3695#endif
3696
3697out:
3698 return rc;
3699}
3700
3701/* Later than subsys_initcall() because we depend on stuff initialised there */
3702fs_initcall(af_unix_init);
1/*
2 * NET4: Implementation of BSD Unix domain sockets.
3 *
4 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * Fixes:
12 * Linus Torvalds : Assorted bug cures.
13 * Niibe Yutaka : async I/O support.
14 * Carsten Paeth : PF_UNIX check, address fixes.
15 * Alan Cox : Limit size of allocated blocks.
16 * Alan Cox : Fixed the stupid socketpair bug.
17 * Alan Cox : BSD compatibility fine tuning.
18 * Alan Cox : Fixed a bug in connect when interrupted.
19 * Alan Cox : Sorted out a proper draft version of
20 * file descriptor passing hacked up from
21 * Mike Shaver's work.
22 * Marty Leisner : Fixes to fd passing
23 * Nick Nevin : recvmsg bugfix.
24 * Alan Cox : Started proper garbage collector
25 * Heiko EiBfeldt : Missing verify_area check
26 * Alan Cox : Started POSIXisms
27 * Andreas Schwab : Replace inode by dentry for proper
28 * reference counting
29 * Kirk Petersen : Made this a module
30 * Christoph Rohland : Elegant non-blocking accept/connect algorithm.
31 * Lots of bug fixes.
32 * Alexey Kuznetosv : Repaired (I hope) bugs introduces
33 * by above two patches.
34 * Andrea Arcangeli : If possible we block in connect(2)
35 * if the max backlog of the listen socket
36 * is been reached. This won't break
37 * old apps and it will avoid huge amount
38 * of socks hashed (this for unix_gc()
39 * performances reasons).
40 * Security fix that limits the max
41 * number of socks to 2*max_files and
42 * the number of skb queueable in the
43 * dgram receiver.
44 * Artur Skawina : Hash function optimizations
45 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
46 * Malcolm Beattie : Set peercred for socketpair
47 * Michal Ostrowski : Module initialization cleanup.
48 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT,
49 * the core infrastructure is doing that
50 * for all net proto families now (2.5.69+)
51 *
52 *
53 * Known differences from reference BSD that was tested:
54 *
55 * [TO FIX]
56 * ECONNREFUSED is not returned from one end of a connected() socket to the
57 * other the moment one end closes.
58 * fstat() doesn't return st_dev=0, and give the blksize as high water mark
59 * and a fake inode identifier (nor the BSD first socket fstat twice bug).
60 * [NOT TO FIX]
61 * accept() returns a path name even if the connecting socket has closed
62 * in the meantime (BSD loses the path and gives up).
63 * accept() returns 0 length path for an unbound connector. BSD returns 16
64 * and a null first byte in the path (but not for gethost/peername - BSD bug ??)
65 * socketpair(...SOCK_RAW..) doesn't panic the kernel.
66 * BSD af_unix apparently has connect forgetting to block properly.
67 * (need to check this with the POSIX spec in detail)
68 *
69 * Differences from 2.0.0-11-... (ANK)
70 * Bug fixes and improvements.
71 * - client shutdown killed server socket.
72 * - removed all useless cli/sti pairs.
73 *
74 * Semantic changes/extensions.
75 * - generic control message passing.
76 * - SCM_CREDENTIALS control message.
77 * - "Abstract" (not FS based) socket bindings.
78 * Abstract names are sequences of bytes (not zero terminated)
79 * started by 0, so that this name space does not intersect
80 * with BSD names.
81 */
82
83#include <linux/module.h>
84#include <linux/kernel.h>
85#include <linux/signal.h>
86#include <linux/sched.h>
87#include <linux/errno.h>
88#include <linux/string.h>
89#include <linux/stat.h>
90#include <linux/dcache.h>
91#include <linux/namei.h>
92#include <linux/socket.h>
93#include <linux/un.h>
94#include <linux/fcntl.h>
95#include <linux/termios.h>
96#include <linux/sockios.h>
97#include <linux/net.h>
98#include <linux/in.h>
99#include <linux/fs.h>
100#include <linux/slab.h>
101#include <asm/uaccess.h>
102#include <linux/skbuff.h>
103#include <linux/netdevice.h>
104#include <net/net_namespace.h>
105#include <net/sock.h>
106#include <net/tcp_states.h>
107#include <net/af_unix.h>
108#include <linux/proc_fs.h>
109#include <linux/seq_file.h>
110#include <net/scm.h>
111#include <linux/init.h>
112#include <linux/poll.h>
113#include <linux/rtnetlink.h>
114#include <linux/mount.h>
115#include <net/checksum.h>
116#include <linux/security.h>
117
118static struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
119static DEFINE_SPINLOCK(unix_table_lock);
120static atomic_long_t unix_nr_socks;
121
122#define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE])
123
124#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
125
126#ifdef CONFIG_SECURITY_NETWORK
127static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
128{
129 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
130}
131
132static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
133{
134 scm->secid = *UNIXSID(skb);
135}
136#else
137static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
138{ }
139
140static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
141{ }
142#endif /* CONFIG_SECURITY_NETWORK */
143
144/*
145 * SMP locking strategy:
146 * hash table is protected with spinlock unix_table_lock
147 * each socket state is protected by separate spin lock.
148 */
149
150static inline unsigned unix_hash_fold(__wsum n)
151{
152 unsigned hash = (__force unsigned)n;
153 hash ^= hash>>16;
154 hash ^= hash>>8;
155 return hash&(UNIX_HASH_SIZE-1);
156}
157
158#define unix_peer(sk) (unix_sk(sk)->peer)
159
160static inline int unix_our_peer(struct sock *sk, struct sock *osk)
161{
162 return unix_peer(osk) == sk;
163}
164
165static inline int unix_may_send(struct sock *sk, struct sock *osk)
166{
167 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
168}
169
170static inline int unix_recvq_full(struct sock const *sk)
171{
172 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
173}
174
175static struct sock *unix_peer_get(struct sock *s)
176{
177 struct sock *peer;
178
179 unix_state_lock(s);
180 peer = unix_peer(s);
181 if (peer)
182 sock_hold(peer);
183 unix_state_unlock(s);
184 return peer;
185}
186
187static inline void unix_release_addr(struct unix_address *addr)
188{
189 if (atomic_dec_and_test(&addr->refcnt))
190 kfree(addr);
191}
192
193/*
194 * Check unix socket name:
195 * - should be not zero length.
196 * - if started by not zero, should be NULL terminated (FS object)
197 * - if started by zero, it is abstract name.
198 */
199
200static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned *hashp)
201{
202 if (len <= sizeof(short) || len > sizeof(*sunaddr))
203 return -EINVAL;
204 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
205 return -EINVAL;
206 if (sunaddr->sun_path[0]) {
207 /*
208 * This may look like an off by one error but it is a bit more
209 * subtle. 108 is the longest valid AF_UNIX path for a binding.
210 * sun_path[108] doesn't as such exist. However in kernel space
211 * we are guaranteed that it is a valid memory location in our
212 * kernel address buffer.
213 */
214 ((char *)sunaddr)[len] = 0;
215 len = strlen(sunaddr->sun_path)+1+sizeof(short);
216 return len;
217 }
218
219 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
220 return len;
221}
222
223static void __unix_remove_socket(struct sock *sk)
224{
225 sk_del_node_init(sk);
226}
227
228static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
229{
230 WARN_ON(!sk_unhashed(sk));
231 sk_add_node(sk, list);
232}
233
234static inline void unix_remove_socket(struct sock *sk)
235{
236 spin_lock(&unix_table_lock);
237 __unix_remove_socket(sk);
238 spin_unlock(&unix_table_lock);
239}
240
241static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
242{
243 spin_lock(&unix_table_lock);
244 __unix_insert_socket(list, sk);
245 spin_unlock(&unix_table_lock);
246}
247
248static struct sock *__unix_find_socket_byname(struct net *net,
249 struct sockaddr_un *sunname,
250 int len, int type, unsigned hash)
251{
252 struct sock *s;
253 struct hlist_node *node;
254
255 sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
256 struct unix_sock *u = unix_sk(s);
257
258 if (!net_eq(sock_net(s), net))
259 continue;
260
261 if (u->addr->len == len &&
262 !memcmp(u->addr->name, sunname, len))
263 goto found;
264 }
265 s = NULL;
266found:
267 return s;
268}
269
270static inline struct sock *unix_find_socket_byname(struct net *net,
271 struct sockaddr_un *sunname,
272 int len, int type,
273 unsigned hash)
274{
275 struct sock *s;
276
277 spin_lock(&unix_table_lock);
278 s = __unix_find_socket_byname(net, sunname, len, type, hash);
279 if (s)
280 sock_hold(s);
281 spin_unlock(&unix_table_lock);
282 return s;
283}
284
285static struct sock *unix_find_socket_byinode(struct inode *i)
286{
287 struct sock *s;
288 struct hlist_node *node;
289
290 spin_lock(&unix_table_lock);
291 sk_for_each(s, node,
292 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
293 struct dentry *dentry = unix_sk(s)->dentry;
294
295 if (dentry && dentry->d_inode == i) {
296 sock_hold(s);
297 goto found;
298 }
299 }
300 s = NULL;
301found:
302 spin_unlock(&unix_table_lock);
303 return s;
304}
305
306static inline int unix_writable(struct sock *sk)
307{
308 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
309}
310
311static void unix_write_space(struct sock *sk)
312{
313 struct socket_wq *wq;
314
315 rcu_read_lock();
316 if (unix_writable(sk)) {
317 wq = rcu_dereference(sk->sk_wq);
318 if (wq_has_sleeper(wq))
319 wake_up_interruptible_sync_poll(&wq->wait,
320 POLLOUT | POLLWRNORM | POLLWRBAND);
321 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
322 }
323 rcu_read_unlock();
324}
325
326/* When dgram socket disconnects (or changes its peer), we clear its receive
327 * queue of packets arrived from previous peer. First, it allows to do
328 * flow control based only on wmem_alloc; second, sk connected to peer
329 * may receive messages only from that peer. */
330static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
331{
332 if (!skb_queue_empty(&sk->sk_receive_queue)) {
333 skb_queue_purge(&sk->sk_receive_queue);
334 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
335
336 /* If one link of bidirectional dgram pipe is disconnected,
337 * we signal error. Messages are lost. Do not make this,
338 * when peer was not connected to us.
339 */
340 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
341 other->sk_err = ECONNRESET;
342 other->sk_error_report(other);
343 }
344 }
345}
346
347static void unix_sock_destructor(struct sock *sk)
348{
349 struct unix_sock *u = unix_sk(sk);
350
351 skb_queue_purge(&sk->sk_receive_queue);
352
353 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
354 WARN_ON(!sk_unhashed(sk));
355 WARN_ON(sk->sk_socket);
356 if (!sock_flag(sk, SOCK_DEAD)) {
357 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk);
358 return;
359 }
360
361 if (u->addr)
362 unix_release_addr(u->addr);
363
364 atomic_long_dec(&unix_nr_socks);
365 local_bh_disable();
366 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
367 local_bh_enable();
368#ifdef UNIX_REFCNT_DEBUG
369 printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk,
370 atomic_long_read(&unix_nr_socks));
371#endif
372}
373
374static int unix_release_sock(struct sock *sk, int embrion)
375{
376 struct unix_sock *u = unix_sk(sk);
377 struct dentry *dentry;
378 struct vfsmount *mnt;
379 struct sock *skpair;
380 struct sk_buff *skb;
381 int state;
382
383 unix_remove_socket(sk);
384
385 /* Clear state */
386 unix_state_lock(sk);
387 sock_orphan(sk);
388 sk->sk_shutdown = SHUTDOWN_MASK;
389 dentry = u->dentry;
390 u->dentry = NULL;
391 mnt = u->mnt;
392 u->mnt = NULL;
393 state = sk->sk_state;
394 sk->sk_state = TCP_CLOSE;
395 unix_state_unlock(sk);
396
397 wake_up_interruptible_all(&u->peer_wait);
398
399 skpair = unix_peer(sk);
400
401 if (skpair != NULL) {
402 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
403 unix_state_lock(skpair);
404 /* No more writes */
405 skpair->sk_shutdown = SHUTDOWN_MASK;
406 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
407 skpair->sk_err = ECONNRESET;
408 unix_state_unlock(skpair);
409 skpair->sk_state_change(skpair);
410 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
411 }
412 sock_put(skpair); /* It may now die */
413 unix_peer(sk) = NULL;
414 }
415
416 /* Try to flush out this socket. Throw out buffers at least */
417
418 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
419 if (state == TCP_LISTEN)
420 unix_release_sock(skb->sk, 1);
421 /* passed fds are erased in the kfree_skb hook */
422 kfree_skb(skb);
423 }
424
425 if (dentry) {
426 dput(dentry);
427 mntput(mnt);
428 }
429
430 sock_put(sk);
431
432 /* ---- Socket is dead now and most probably destroyed ---- */
433
434 /*
435 * Fixme: BSD difference: In BSD all sockets connected to use get
436 * ECONNRESET and we die on the spot. In Linux we behave
437 * like files and pipes do and wait for the last
438 * dereference.
439 *
440 * Can't we simply set sock->err?
441 *
442 * What the above comment does talk about? --ANK(980817)
443 */
444
445 if (unix_tot_inflight)
446 unix_gc(); /* Garbage collect fds */
447
448 return 0;
449}
450
451static void init_peercred(struct sock *sk)
452{
453 put_pid(sk->sk_peer_pid);
454 if (sk->sk_peer_cred)
455 put_cred(sk->sk_peer_cred);
456 sk->sk_peer_pid = get_pid(task_tgid(current));
457 sk->sk_peer_cred = get_current_cred();
458}
459
460static void copy_peercred(struct sock *sk, struct sock *peersk)
461{
462 put_pid(sk->sk_peer_pid);
463 if (sk->sk_peer_cred)
464 put_cred(sk->sk_peer_cred);
465 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
466 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
467}
468
469static int unix_listen(struct socket *sock, int backlog)
470{
471 int err;
472 struct sock *sk = sock->sk;
473 struct unix_sock *u = unix_sk(sk);
474 struct pid *old_pid = NULL;
475 const struct cred *old_cred = NULL;
476
477 err = -EOPNOTSUPP;
478 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
479 goto out; /* Only stream/seqpacket sockets accept */
480 err = -EINVAL;
481 if (!u->addr)
482 goto out; /* No listens on an unbound socket */
483 unix_state_lock(sk);
484 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
485 goto out_unlock;
486 if (backlog > sk->sk_max_ack_backlog)
487 wake_up_interruptible_all(&u->peer_wait);
488 sk->sk_max_ack_backlog = backlog;
489 sk->sk_state = TCP_LISTEN;
490 /* set credentials so connect can copy them */
491 init_peercred(sk);
492 err = 0;
493
494out_unlock:
495 unix_state_unlock(sk);
496 put_pid(old_pid);
497 if (old_cred)
498 put_cred(old_cred);
499out:
500 return err;
501}
502
503static int unix_release(struct socket *);
504static int unix_bind(struct socket *, struct sockaddr *, int);
505static int unix_stream_connect(struct socket *, struct sockaddr *,
506 int addr_len, int flags);
507static int unix_socketpair(struct socket *, struct socket *);
508static int unix_accept(struct socket *, struct socket *, int);
509static int unix_getname(struct socket *, struct sockaddr *, int *, int);
510static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
511static unsigned int unix_dgram_poll(struct file *, struct socket *,
512 poll_table *);
513static int unix_ioctl(struct socket *, unsigned int, unsigned long);
514static int unix_shutdown(struct socket *, int);
515static int unix_stream_sendmsg(struct kiocb *, struct socket *,
516 struct msghdr *, size_t);
517static int unix_stream_recvmsg(struct kiocb *, struct socket *,
518 struct msghdr *, size_t, int);
519static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
520 struct msghdr *, size_t);
521static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
522 struct msghdr *, size_t, int);
523static int unix_dgram_connect(struct socket *, struct sockaddr *,
524 int, int);
525static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
526 struct msghdr *, size_t);
527static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
528 struct msghdr *, size_t, int);
529
530static const struct proto_ops unix_stream_ops = {
531 .family = PF_UNIX,
532 .owner = THIS_MODULE,
533 .release = unix_release,
534 .bind = unix_bind,
535 .connect = unix_stream_connect,
536 .socketpair = unix_socketpair,
537 .accept = unix_accept,
538 .getname = unix_getname,
539 .poll = unix_poll,
540 .ioctl = unix_ioctl,
541 .listen = unix_listen,
542 .shutdown = unix_shutdown,
543 .setsockopt = sock_no_setsockopt,
544 .getsockopt = sock_no_getsockopt,
545 .sendmsg = unix_stream_sendmsg,
546 .recvmsg = unix_stream_recvmsg,
547 .mmap = sock_no_mmap,
548 .sendpage = sock_no_sendpage,
549};
550
551static const struct proto_ops unix_dgram_ops = {
552 .family = PF_UNIX,
553 .owner = THIS_MODULE,
554 .release = unix_release,
555 .bind = unix_bind,
556 .connect = unix_dgram_connect,
557 .socketpair = unix_socketpair,
558 .accept = sock_no_accept,
559 .getname = unix_getname,
560 .poll = unix_dgram_poll,
561 .ioctl = unix_ioctl,
562 .listen = sock_no_listen,
563 .shutdown = unix_shutdown,
564 .setsockopt = sock_no_setsockopt,
565 .getsockopt = sock_no_getsockopt,
566 .sendmsg = unix_dgram_sendmsg,
567 .recvmsg = unix_dgram_recvmsg,
568 .mmap = sock_no_mmap,
569 .sendpage = sock_no_sendpage,
570};
571
572static const struct proto_ops unix_seqpacket_ops = {
573 .family = PF_UNIX,
574 .owner = THIS_MODULE,
575 .release = unix_release,
576 .bind = unix_bind,
577 .connect = unix_stream_connect,
578 .socketpair = unix_socketpair,
579 .accept = unix_accept,
580 .getname = unix_getname,
581 .poll = unix_dgram_poll,
582 .ioctl = unix_ioctl,
583 .listen = unix_listen,
584 .shutdown = unix_shutdown,
585 .setsockopt = sock_no_setsockopt,
586 .getsockopt = sock_no_getsockopt,
587 .sendmsg = unix_seqpacket_sendmsg,
588 .recvmsg = unix_seqpacket_recvmsg,
589 .mmap = sock_no_mmap,
590 .sendpage = sock_no_sendpage,
591};
592
593static struct proto unix_proto = {
594 .name = "UNIX",
595 .owner = THIS_MODULE,
596 .obj_size = sizeof(struct unix_sock),
597};
598
599/*
600 * AF_UNIX sockets do not interact with hardware, hence they
601 * dont trigger interrupts - so it's safe for them to have
602 * bh-unsafe locking for their sk_receive_queue.lock. Split off
603 * this special lock-class by reinitializing the spinlock key:
604 */
605static struct lock_class_key af_unix_sk_receive_queue_lock_key;
606
607static struct sock *unix_create1(struct net *net, struct socket *sock)
608{
609 struct sock *sk = NULL;
610 struct unix_sock *u;
611
612 atomic_long_inc(&unix_nr_socks);
613 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
614 goto out;
615
616 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
617 if (!sk)
618 goto out;
619
620 sock_init_data(sock, sk);
621 lockdep_set_class(&sk->sk_receive_queue.lock,
622 &af_unix_sk_receive_queue_lock_key);
623
624 sk->sk_write_space = unix_write_space;
625 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
626 sk->sk_destruct = unix_sock_destructor;
627 u = unix_sk(sk);
628 u->dentry = NULL;
629 u->mnt = NULL;
630 spin_lock_init(&u->lock);
631 atomic_long_set(&u->inflight, 0);
632 INIT_LIST_HEAD(&u->link);
633 mutex_init(&u->readlock); /* single task reading lock */
634 init_waitqueue_head(&u->peer_wait);
635 unix_insert_socket(unix_sockets_unbound, sk);
636out:
637 if (sk == NULL)
638 atomic_long_dec(&unix_nr_socks);
639 else {
640 local_bh_disable();
641 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
642 local_bh_enable();
643 }
644 return sk;
645}
646
647static int unix_create(struct net *net, struct socket *sock, int protocol,
648 int kern)
649{
650 if (protocol && protocol != PF_UNIX)
651 return -EPROTONOSUPPORT;
652
653 sock->state = SS_UNCONNECTED;
654
655 switch (sock->type) {
656 case SOCK_STREAM:
657 sock->ops = &unix_stream_ops;
658 break;
659 /*
660 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
661 * nothing uses it.
662 */
663 case SOCK_RAW:
664 sock->type = SOCK_DGRAM;
665 case SOCK_DGRAM:
666 sock->ops = &unix_dgram_ops;
667 break;
668 case SOCK_SEQPACKET:
669 sock->ops = &unix_seqpacket_ops;
670 break;
671 default:
672 return -ESOCKTNOSUPPORT;
673 }
674
675 return unix_create1(net, sock) ? 0 : -ENOMEM;
676}
677
678static int unix_release(struct socket *sock)
679{
680 struct sock *sk = sock->sk;
681
682 if (!sk)
683 return 0;
684
685 sock->sk = NULL;
686
687 return unix_release_sock(sk, 0);
688}
689
690static int unix_autobind(struct socket *sock)
691{
692 struct sock *sk = sock->sk;
693 struct net *net = sock_net(sk);
694 struct unix_sock *u = unix_sk(sk);
695 static u32 ordernum = 1;
696 struct unix_address *addr;
697 int err;
698 unsigned int retries = 0;
699
700 mutex_lock(&u->readlock);
701
702 err = 0;
703 if (u->addr)
704 goto out;
705
706 err = -ENOMEM;
707 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
708 if (!addr)
709 goto out;
710
711 addr->name->sun_family = AF_UNIX;
712 atomic_set(&addr->refcnt, 1);
713
714retry:
715 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
716 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
717
718 spin_lock(&unix_table_lock);
719 ordernum = (ordernum+1)&0xFFFFF;
720
721 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
722 addr->hash)) {
723 spin_unlock(&unix_table_lock);
724 /*
725 * __unix_find_socket_byname() may take long time if many names
726 * are already in use.
727 */
728 cond_resched();
729 /* Give up if all names seems to be in use. */
730 if (retries++ == 0xFFFFF) {
731 err = -ENOSPC;
732 kfree(addr);
733 goto out;
734 }
735 goto retry;
736 }
737 addr->hash ^= sk->sk_type;
738
739 __unix_remove_socket(sk);
740 u->addr = addr;
741 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
742 spin_unlock(&unix_table_lock);
743 err = 0;
744
745out: mutex_unlock(&u->readlock);
746 return err;
747}
748
749static struct sock *unix_find_other(struct net *net,
750 struct sockaddr_un *sunname, int len,
751 int type, unsigned hash, int *error)
752{
753 struct sock *u;
754 struct path path;
755 int err = 0;
756
757 if (sunname->sun_path[0]) {
758 struct inode *inode;
759 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
760 if (err)
761 goto fail;
762 inode = path.dentry->d_inode;
763 err = inode_permission(inode, MAY_WRITE);
764 if (err)
765 goto put_fail;
766
767 err = -ECONNREFUSED;
768 if (!S_ISSOCK(inode->i_mode))
769 goto put_fail;
770 u = unix_find_socket_byinode(inode);
771 if (!u)
772 goto put_fail;
773
774 if (u->sk_type == type)
775 touch_atime(path.mnt, path.dentry);
776
777 path_put(&path);
778
779 err = -EPROTOTYPE;
780 if (u->sk_type != type) {
781 sock_put(u);
782 goto fail;
783 }
784 } else {
785 err = -ECONNREFUSED;
786 u = unix_find_socket_byname(net, sunname, len, type, hash);
787 if (u) {
788 struct dentry *dentry;
789 dentry = unix_sk(u)->dentry;
790 if (dentry)
791 touch_atime(unix_sk(u)->mnt, dentry);
792 } else
793 goto fail;
794 }
795 return u;
796
797put_fail:
798 path_put(&path);
799fail:
800 *error = err;
801 return NULL;
802}
803
804
805static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
806{
807 struct sock *sk = sock->sk;
808 struct net *net = sock_net(sk);
809 struct unix_sock *u = unix_sk(sk);
810 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
811 char *sun_path = sunaddr->sun_path;
812 struct dentry *dentry = NULL;
813 struct path path;
814 int err;
815 unsigned hash;
816 struct unix_address *addr;
817 struct hlist_head *list;
818
819 err = -EINVAL;
820 if (sunaddr->sun_family != AF_UNIX)
821 goto out;
822
823 if (addr_len == sizeof(short)) {
824 err = unix_autobind(sock);
825 goto out;
826 }
827
828 err = unix_mkname(sunaddr, addr_len, &hash);
829 if (err < 0)
830 goto out;
831 addr_len = err;
832
833 mutex_lock(&u->readlock);
834
835 err = -EINVAL;
836 if (u->addr)
837 goto out_up;
838
839 err = -ENOMEM;
840 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
841 if (!addr)
842 goto out_up;
843
844 memcpy(addr->name, sunaddr, addr_len);
845 addr->len = addr_len;
846 addr->hash = hash ^ sk->sk_type;
847 atomic_set(&addr->refcnt, 1);
848
849 if (sun_path[0]) {
850 unsigned int mode;
851 err = 0;
852 /*
853 * Get the parent directory, calculate the hash for last
854 * component.
855 */
856 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
857 err = PTR_ERR(dentry);
858 if (IS_ERR(dentry))
859 goto out_mknod_parent;
860
861 /*
862 * All right, let's create it.
863 */
864 mode = S_IFSOCK |
865 (SOCK_INODE(sock)->i_mode & ~current_umask());
866 err = mnt_want_write(path.mnt);
867 if (err)
868 goto out_mknod_dput;
869 err = security_path_mknod(&path, dentry, mode, 0);
870 if (err)
871 goto out_mknod_drop_write;
872 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
873out_mknod_drop_write:
874 mnt_drop_write(path.mnt);
875 if (err)
876 goto out_mknod_dput;
877 mutex_unlock(&path.dentry->d_inode->i_mutex);
878 dput(path.dentry);
879 path.dentry = dentry;
880
881 addr->hash = UNIX_HASH_SIZE;
882 }
883
884 spin_lock(&unix_table_lock);
885
886 if (!sun_path[0]) {
887 err = -EADDRINUSE;
888 if (__unix_find_socket_byname(net, sunaddr, addr_len,
889 sk->sk_type, hash)) {
890 unix_release_addr(addr);
891 goto out_unlock;
892 }
893
894 list = &unix_socket_table[addr->hash];
895 } else {
896 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
897 u->dentry = path.dentry;
898 u->mnt = path.mnt;
899 }
900
901 err = 0;
902 __unix_remove_socket(sk);
903 u->addr = addr;
904 __unix_insert_socket(list, sk);
905
906out_unlock:
907 spin_unlock(&unix_table_lock);
908out_up:
909 mutex_unlock(&u->readlock);
910out:
911 return err;
912
913out_mknod_dput:
914 dput(dentry);
915 mutex_unlock(&path.dentry->d_inode->i_mutex);
916 path_put(&path);
917out_mknod_parent:
918 if (err == -EEXIST)
919 err = -EADDRINUSE;
920 unix_release_addr(addr);
921 goto out_up;
922}
923
924static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
925{
926 if (unlikely(sk1 == sk2) || !sk2) {
927 unix_state_lock(sk1);
928 return;
929 }
930 if (sk1 < sk2) {
931 unix_state_lock(sk1);
932 unix_state_lock_nested(sk2);
933 } else {
934 unix_state_lock(sk2);
935 unix_state_lock_nested(sk1);
936 }
937}
938
939static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
940{
941 if (unlikely(sk1 == sk2) || !sk2) {
942 unix_state_unlock(sk1);
943 return;
944 }
945 unix_state_unlock(sk1);
946 unix_state_unlock(sk2);
947}
948
949static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
950 int alen, int flags)
951{
952 struct sock *sk = sock->sk;
953 struct net *net = sock_net(sk);
954 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
955 struct sock *other;
956 unsigned hash;
957 int err;
958
959 if (addr->sa_family != AF_UNSPEC) {
960 err = unix_mkname(sunaddr, alen, &hash);
961 if (err < 0)
962 goto out;
963 alen = err;
964
965 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
966 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
967 goto out;
968
969restart:
970 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
971 if (!other)
972 goto out;
973
974 unix_state_double_lock(sk, other);
975
976 /* Apparently VFS overslept socket death. Retry. */
977 if (sock_flag(other, SOCK_DEAD)) {
978 unix_state_double_unlock(sk, other);
979 sock_put(other);
980 goto restart;
981 }
982
983 err = -EPERM;
984 if (!unix_may_send(sk, other))
985 goto out_unlock;
986
987 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
988 if (err)
989 goto out_unlock;
990
991 } else {
992 /*
993 * 1003.1g breaking connected state with AF_UNSPEC
994 */
995 other = NULL;
996 unix_state_double_lock(sk, other);
997 }
998
999 /*
1000 * If it was connected, reconnect.
1001 */
1002 if (unix_peer(sk)) {
1003 struct sock *old_peer = unix_peer(sk);
1004 unix_peer(sk) = other;
1005 unix_state_double_unlock(sk, other);
1006
1007 if (other != old_peer)
1008 unix_dgram_disconnected(sk, old_peer);
1009 sock_put(old_peer);
1010 } else {
1011 unix_peer(sk) = other;
1012 unix_state_double_unlock(sk, other);
1013 }
1014 return 0;
1015
1016out_unlock:
1017 unix_state_double_unlock(sk, other);
1018 sock_put(other);
1019out:
1020 return err;
1021}
1022
1023static long unix_wait_for_peer(struct sock *other, long timeo)
1024{
1025 struct unix_sock *u = unix_sk(other);
1026 int sched;
1027 DEFINE_WAIT(wait);
1028
1029 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1030
1031 sched = !sock_flag(other, SOCK_DEAD) &&
1032 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1033 unix_recvq_full(other);
1034
1035 unix_state_unlock(other);
1036
1037 if (sched)
1038 timeo = schedule_timeout(timeo);
1039
1040 finish_wait(&u->peer_wait, &wait);
1041 return timeo;
1042}
1043
1044static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1045 int addr_len, int flags)
1046{
1047 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1048 struct sock *sk = sock->sk;
1049 struct net *net = sock_net(sk);
1050 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1051 struct sock *newsk = NULL;
1052 struct sock *other = NULL;
1053 struct sk_buff *skb = NULL;
1054 unsigned hash;
1055 int st;
1056 int err;
1057 long timeo;
1058
1059 err = unix_mkname(sunaddr, addr_len, &hash);
1060 if (err < 0)
1061 goto out;
1062 addr_len = err;
1063
1064 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1065 (err = unix_autobind(sock)) != 0)
1066 goto out;
1067
1068 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1069
1070 /* First of all allocate resources.
1071 If we will make it after state is locked,
1072 we will have to recheck all again in any case.
1073 */
1074
1075 err = -ENOMEM;
1076
1077 /* create new sock for complete connection */
1078 newsk = unix_create1(sock_net(sk), NULL);
1079 if (newsk == NULL)
1080 goto out;
1081
1082 /* Allocate skb for sending to listening sock */
1083 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1084 if (skb == NULL)
1085 goto out;
1086
1087restart:
1088 /* Find listening sock. */
1089 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1090 if (!other)
1091 goto out;
1092
1093 /* Latch state of peer */
1094 unix_state_lock(other);
1095
1096 /* Apparently VFS overslept socket death. Retry. */
1097 if (sock_flag(other, SOCK_DEAD)) {
1098 unix_state_unlock(other);
1099 sock_put(other);
1100 goto restart;
1101 }
1102
1103 err = -ECONNREFUSED;
1104 if (other->sk_state != TCP_LISTEN)
1105 goto out_unlock;
1106 if (other->sk_shutdown & RCV_SHUTDOWN)
1107 goto out_unlock;
1108
1109 if (unix_recvq_full(other)) {
1110 err = -EAGAIN;
1111 if (!timeo)
1112 goto out_unlock;
1113
1114 timeo = unix_wait_for_peer(other, timeo);
1115
1116 err = sock_intr_errno(timeo);
1117 if (signal_pending(current))
1118 goto out;
1119 sock_put(other);
1120 goto restart;
1121 }
1122
1123 /* Latch our state.
1124
1125 It is tricky place. We need to grab our state lock and cannot
1126 drop lock on peer. It is dangerous because deadlock is
1127 possible. Connect to self case and simultaneous
1128 attempt to connect are eliminated by checking socket
1129 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1130 check this before attempt to grab lock.
1131
1132 Well, and we have to recheck the state after socket locked.
1133 */
1134 st = sk->sk_state;
1135
1136 switch (st) {
1137 case TCP_CLOSE:
1138 /* This is ok... continue with connect */
1139 break;
1140 case TCP_ESTABLISHED:
1141 /* Socket is already connected */
1142 err = -EISCONN;
1143 goto out_unlock;
1144 default:
1145 err = -EINVAL;
1146 goto out_unlock;
1147 }
1148
1149 unix_state_lock_nested(sk);
1150
1151 if (sk->sk_state != st) {
1152 unix_state_unlock(sk);
1153 unix_state_unlock(other);
1154 sock_put(other);
1155 goto restart;
1156 }
1157
1158 err = security_unix_stream_connect(sk, other, newsk);
1159 if (err) {
1160 unix_state_unlock(sk);
1161 goto out_unlock;
1162 }
1163
1164 /* The way is open! Fastly set all the necessary fields... */
1165
1166 sock_hold(sk);
1167 unix_peer(newsk) = sk;
1168 newsk->sk_state = TCP_ESTABLISHED;
1169 newsk->sk_type = sk->sk_type;
1170 init_peercred(newsk);
1171 newu = unix_sk(newsk);
1172 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1173 otheru = unix_sk(other);
1174
1175 /* copy address information from listening to new sock*/
1176 if (otheru->addr) {
1177 atomic_inc(&otheru->addr->refcnt);
1178 newu->addr = otheru->addr;
1179 }
1180 if (otheru->dentry) {
1181 newu->dentry = dget(otheru->dentry);
1182 newu->mnt = mntget(otheru->mnt);
1183 }
1184
1185 /* Set credentials */
1186 copy_peercred(sk, other);
1187
1188 sock->state = SS_CONNECTED;
1189 sk->sk_state = TCP_ESTABLISHED;
1190 sock_hold(newsk);
1191
1192 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1193 unix_peer(sk) = newsk;
1194
1195 unix_state_unlock(sk);
1196
1197 /* take ten and and send info to listening sock */
1198 spin_lock(&other->sk_receive_queue.lock);
1199 __skb_queue_tail(&other->sk_receive_queue, skb);
1200 spin_unlock(&other->sk_receive_queue.lock);
1201 unix_state_unlock(other);
1202 other->sk_data_ready(other, 0);
1203 sock_put(other);
1204 return 0;
1205
1206out_unlock:
1207 if (other)
1208 unix_state_unlock(other);
1209
1210out:
1211 kfree_skb(skb);
1212 if (newsk)
1213 unix_release_sock(newsk, 0);
1214 if (other)
1215 sock_put(other);
1216 return err;
1217}
1218
1219static int unix_socketpair(struct socket *socka, struct socket *sockb)
1220{
1221 struct sock *ska = socka->sk, *skb = sockb->sk;
1222
1223 /* Join our sockets back to back */
1224 sock_hold(ska);
1225 sock_hold(skb);
1226 unix_peer(ska) = skb;
1227 unix_peer(skb) = ska;
1228 init_peercred(ska);
1229 init_peercred(skb);
1230
1231 if (ska->sk_type != SOCK_DGRAM) {
1232 ska->sk_state = TCP_ESTABLISHED;
1233 skb->sk_state = TCP_ESTABLISHED;
1234 socka->state = SS_CONNECTED;
1235 sockb->state = SS_CONNECTED;
1236 }
1237 return 0;
1238}
1239
1240static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1241{
1242 struct sock *sk = sock->sk;
1243 struct sock *tsk;
1244 struct sk_buff *skb;
1245 int err;
1246
1247 err = -EOPNOTSUPP;
1248 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1249 goto out;
1250
1251 err = -EINVAL;
1252 if (sk->sk_state != TCP_LISTEN)
1253 goto out;
1254
1255 /* If socket state is TCP_LISTEN it cannot change (for now...),
1256 * so that no locks are necessary.
1257 */
1258
1259 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1260 if (!skb) {
1261 /* This means receive shutdown. */
1262 if (err == 0)
1263 err = -EINVAL;
1264 goto out;
1265 }
1266
1267 tsk = skb->sk;
1268 skb_free_datagram(sk, skb);
1269 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1270
1271 /* attach accepted sock to socket */
1272 unix_state_lock(tsk);
1273 newsock->state = SS_CONNECTED;
1274 sock_graft(tsk, newsock);
1275 unix_state_unlock(tsk);
1276 return 0;
1277
1278out:
1279 return err;
1280}
1281
1282
1283static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1284{
1285 struct sock *sk = sock->sk;
1286 struct unix_sock *u;
1287 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1288 int err = 0;
1289
1290 if (peer) {
1291 sk = unix_peer_get(sk);
1292
1293 err = -ENOTCONN;
1294 if (!sk)
1295 goto out;
1296 err = 0;
1297 } else {
1298 sock_hold(sk);
1299 }
1300
1301 u = unix_sk(sk);
1302 unix_state_lock(sk);
1303 if (!u->addr) {
1304 sunaddr->sun_family = AF_UNIX;
1305 sunaddr->sun_path[0] = 0;
1306 *uaddr_len = sizeof(short);
1307 } else {
1308 struct unix_address *addr = u->addr;
1309
1310 *uaddr_len = addr->len;
1311 memcpy(sunaddr, addr->name, *uaddr_len);
1312 }
1313 unix_state_unlock(sk);
1314 sock_put(sk);
1315out:
1316 return err;
1317}
1318
1319static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1320{
1321 int i;
1322
1323 scm->fp = UNIXCB(skb).fp;
1324 UNIXCB(skb).fp = NULL;
1325
1326 for (i = scm->fp->count-1; i >= 0; i--)
1327 unix_notinflight(scm->fp->fp[i]);
1328}
1329
1330static void unix_destruct_scm(struct sk_buff *skb)
1331{
1332 struct scm_cookie scm;
1333 memset(&scm, 0, sizeof(scm));
1334 scm.pid = UNIXCB(skb).pid;
1335 scm.cred = UNIXCB(skb).cred;
1336 if (UNIXCB(skb).fp)
1337 unix_detach_fds(&scm, skb);
1338
1339 /* Alas, it calls VFS */
1340 /* So fscking what? fput() had been SMP-safe since the last Summer */
1341 scm_destroy(&scm);
1342 sock_wfree(skb);
1343}
1344
1345#define MAX_RECURSION_LEVEL 4
1346
1347static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1348{
1349 int i;
1350 unsigned char max_level = 0;
1351 int unix_sock_count = 0;
1352
1353 for (i = scm->fp->count - 1; i >= 0; i--) {
1354 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1355
1356 if (sk) {
1357 unix_sock_count++;
1358 max_level = max(max_level,
1359 unix_sk(sk)->recursion_level);
1360 }
1361 }
1362 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1363 return -ETOOMANYREFS;
1364
1365 /*
1366 * Need to duplicate file references for the sake of garbage
1367 * collection. Otherwise a socket in the fps might become a
1368 * candidate for GC while the skb is not yet queued.
1369 */
1370 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1371 if (!UNIXCB(skb).fp)
1372 return -ENOMEM;
1373
1374 if (unix_sock_count) {
1375 for (i = scm->fp->count - 1; i >= 0; i--)
1376 unix_inflight(scm->fp->fp[i]);
1377 }
1378 return max_level;
1379}
1380
1381static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1382{
1383 int err = 0;
1384 UNIXCB(skb).pid = get_pid(scm->pid);
1385 UNIXCB(skb).cred = get_cred(scm->cred);
1386 UNIXCB(skb).fp = NULL;
1387 if (scm->fp && send_fds)
1388 err = unix_attach_fds(scm, skb);
1389
1390 skb->destructor = unix_destruct_scm;
1391 return err;
1392}
1393
1394/*
1395 * Send AF_UNIX data.
1396 */
1397
1398static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1399 struct msghdr *msg, size_t len)
1400{
1401 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1402 struct sock *sk = sock->sk;
1403 struct net *net = sock_net(sk);
1404 struct unix_sock *u = unix_sk(sk);
1405 struct sockaddr_un *sunaddr = msg->msg_name;
1406 struct sock *other = NULL;
1407 int namelen = 0; /* fake GCC */
1408 int err;
1409 unsigned hash;
1410 struct sk_buff *skb;
1411 long timeo;
1412 struct scm_cookie tmp_scm;
1413 int max_level;
1414
1415 if (NULL == siocb->scm)
1416 siocb->scm = &tmp_scm;
1417 wait_for_unix_gc();
1418 err = scm_send(sock, msg, siocb->scm);
1419 if (err < 0)
1420 return err;
1421
1422 err = -EOPNOTSUPP;
1423 if (msg->msg_flags&MSG_OOB)
1424 goto out;
1425
1426 if (msg->msg_namelen) {
1427 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1428 if (err < 0)
1429 goto out;
1430 namelen = err;
1431 } else {
1432 sunaddr = NULL;
1433 err = -ENOTCONN;
1434 other = unix_peer_get(sk);
1435 if (!other)
1436 goto out;
1437 }
1438
1439 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1440 && (err = unix_autobind(sock)) != 0)
1441 goto out;
1442
1443 err = -EMSGSIZE;
1444 if (len > sk->sk_sndbuf - 32)
1445 goto out;
1446
1447 skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1448 if (skb == NULL)
1449 goto out;
1450
1451 err = unix_scm_to_skb(siocb->scm, skb, true);
1452 if (err < 0)
1453 goto out_free;
1454 max_level = err + 1;
1455 unix_get_secdata(siocb->scm, skb);
1456
1457 skb_reset_transport_header(skb);
1458 err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1459 if (err)
1460 goto out_free;
1461
1462 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1463
1464restart:
1465 if (!other) {
1466 err = -ECONNRESET;
1467 if (sunaddr == NULL)
1468 goto out_free;
1469
1470 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1471 hash, &err);
1472 if (other == NULL)
1473 goto out_free;
1474 }
1475
1476 if (sk_filter(other, skb) < 0) {
1477 /* Toss the packet but do not return any error to the sender */
1478 err = len;
1479 goto out_free;
1480 }
1481
1482 unix_state_lock(other);
1483 err = -EPERM;
1484 if (!unix_may_send(sk, other))
1485 goto out_unlock;
1486
1487 if (sock_flag(other, SOCK_DEAD)) {
1488 /*
1489 * Check with 1003.1g - what should
1490 * datagram error
1491 */
1492 unix_state_unlock(other);
1493 sock_put(other);
1494
1495 err = 0;
1496 unix_state_lock(sk);
1497 if (unix_peer(sk) == other) {
1498 unix_peer(sk) = NULL;
1499 unix_state_unlock(sk);
1500
1501 unix_dgram_disconnected(sk, other);
1502 sock_put(other);
1503 err = -ECONNREFUSED;
1504 } else {
1505 unix_state_unlock(sk);
1506 }
1507
1508 other = NULL;
1509 if (err)
1510 goto out_free;
1511 goto restart;
1512 }
1513
1514 err = -EPIPE;
1515 if (other->sk_shutdown & RCV_SHUTDOWN)
1516 goto out_unlock;
1517
1518 if (sk->sk_type != SOCK_SEQPACKET) {
1519 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1520 if (err)
1521 goto out_unlock;
1522 }
1523
1524 if (unix_peer(other) != sk && unix_recvq_full(other)) {
1525 if (!timeo) {
1526 err = -EAGAIN;
1527 goto out_unlock;
1528 }
1529
1530 timeo = unix_wait_for_peer(other, timeo);
1531
1532 err = sock_intr_errno(timeo);
1533 if (signal_pending(current))
1534 goto out_free;
1535
1536 goto restart;
1537 }
1538
1539 if (sock_flag(other, SOCK_RCVTSTAMP))
1540 __net_timestamp(skb);
1541 skb_queue_tail(&other->sk_receive_queue, skb);
1542 if (max_level > unix_sk(other)->recursion_level)
1543 unix_sk(other)->recursion_level = max_level;
1544 unix_state_unlock(other);
1545 other->sk_data_ready(other, len);
1546 sock_put(other);
1547 scm_destroy(siocb->scm);
1548 return len;
1549
1550out_unlock:
1551 unix_state_unlock(other);
1552out_free:
1553 kfree_skb(skb);
1554out:
1555 if (other)
1556 sock_put(other);
1557 scm_destroy(siocb->scm);
1558 return err;
1559}
1560
1561
1562static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1563 struct msghdr *msg, size_t len)
1564{
1565 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1566 struct sock *sk = sock->sk;
1567 struct sock *other = NULL;
1568 int err, size;
1569 struct sk_buff *skb;
1570 int sent = 0;
1571 struct scm_cookie tmp_scm;
1572 bool fds_sent = false;
1573 int max_level;
1574
1575 if (NULL == siocb->scm)
1576 siocb->scm = &tmp_scm;
1577 wait_for_unix_gc();
1578 err = scm_send(sock, msg, siocb->scm);
1579 if (err < 0)
1580 return err;
1581
1582 err = -EOPNOTSUPP;
1583 if (msg->msg_flags&MSG_OOB)
1584 goto out_err;
1585
1586 if (msg->msg_namelen) {
1587 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1588 goto out_err;
1589 } else {
1590 err = -ENOTCONN;
1591 other = unix_peer(sk);
1592 if (!other)
1593 goto out_err;
1594 }
1595
1596 if (sk->sk_shutdown & SEND_SHUTDOWN)
1597 goto pipe_err;
1598
1599 while (sent < len) {
1600 /*
1601 * Optimisation for the fact that under 0.01% of X
1602 * messages typically need breaking up.
1603 */
1604
1605 size = len-sent;
1606
1607 /* Keep two messages in the pipe so it schedules better */
1608 if (size > ((sk->sk_sndbuf >> 1) - 64))
1609 size = (sk->sk_sndbuf >> 1) - 64;
1610
1611 if (size > SKB_MAX_ALLOC)
1612 size = SKB_MAX_ALLOC;
1613
1614 /*
1615 * Grab a buffer
1616 */
1617
1618 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1619 &err);
1620
1621 if (skb == NULL)
1622 goto out_err;
1623
1624 /*
1625 * If you pass two values to the sock_alloc_send_skb
1626 * it tries to grab the large buffer with GFP_NOFS
1627 * (which can fail easily), and if it fails grab the
1628 * fallback size buffer which is under a page and will
1629 * succeed. [Alan]
1630 */
1631 size = min_t(int, size, skb_tailroom(skb));
1632
1633
1634 /* Only send the fds in the first buffer */
1635 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1636 if (err < 0) {
1637 kfree_skb(skb);
1638 goto out_err;
1639 }
1640 max_level = err + 1;
1641 fds_sent = true;
1642
1643 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1644 if (err) {
1645 kfree_skb(skb);
1646 goto out_err;
1647 }
1648
1649 unix_state_lock(other);
1650
1651 if (sock_flag(other, SOCK_DEAD) ||
1652 (other->sk_shutdown & RCV_SHUTDOWN))
1653 goto pipe_err_free;
1654
1655 skb_queue_tail(&other->sk_receive_queue, skb);
1656 if (max_level > unix_sk(other)->recursion_level)
1657 unix_sk(other)->recursion_level = max_level;
1658 unix_state_unlock(other);
1659 other->sk_data_ready(other, size);
1660 sent += size;
1661 }
1662
1663 scm_destroy(siocb->scm);
1664 siocb->scm = NULL;
1665
1666 return sent;
1667
1668pipe_err_free:
1669 unix_state_unlock(other);
1670 kfree_skb(skb);
1671pipe_err:
1672 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1673 send_sig(SIGPIPE, current, 0);
1674 err = -EPIPE;
1675out_err:
1676 scm_destroy(siocb->scm);
1677 siocb->scm = NULL;
1678 return sent ? : err;
1679}
1680
1681static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1682 struct msghdr *msg, size_t len)
1683{
1684 int err;
1685 struct sock *sk = sock->sk;
1686
1687 err = sock_error(sk);
1688 if (err)
1689 return err;
1690
1691 if (sk->sk_state != TCP_ESTABLISHED)
1692 return -ENOTCONN;
1693
1694 if (msg->msg_namelen)
1695 msg->msg_namelen = 0;
1696
1697 return unix_dgram_sendmsg(kiocb, sock, msg, len);
1698}
1699
1700static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
1701 struct msghdr *msg, size_t size,
1702 int flags)
1703{
1704 struct sock *sk = sock->sk;
1705
1706 if (sk->sk_state != TCP_ESTABLISHED)
1707 return -ENOTCONN;
1708
1709 return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
1710}
1711
1712static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1713{
1714 struct unix_sock *u = unix_sk(sk);
1715
1716 msg->msg_namelen = 0;
1717 if (u->addr) {
1718 msg->msg_namelen = u->addr->len;
1719 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1720 }
1721}
1722
1723static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1724 struct msghdr *msg, size_t size,
1725 int flags)
1726{
1727 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1728 struct scm_cookie tmp_scm;
1729 struct sock *sk = sock->sk;
1730 struct unix_sock *u = unix_sk(sk);
1731 int noblock = flags & MSG_DONTWAIT;
1732 struct sk_buff *skb;
1733 int err;
1734
1735 err = -EOPNOTSUPP;
1736 if (flags&MSG_OOB)
1737 goto out;
1738
1739 msg->msg_namelen = 0;
1740
1741 err = mutex_lock_interruptible(&u->readlock);
1742 if (err) {
1743 err = sock_intr_errno(sock_rcvtimeo(sk, noblock));
1744 goto out;
1745 }
1746
1747 skb = skb_recv_datagram(sk, flags, noblock, &err);
1748 if (!skb) {
1749 unix_state_lock(sk);
1750 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1751 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1752 (sk->sk_shutdown & RCV_SHUTDOWN))
1753 err = 0;
1754 unix_state_unlock(sk);
1755 goto out_unlock;
1756 }
1757
1758 wake_up_interruptible_sync_poll(&u->peer_wait,
1759 POLLOUT | POLLWRNORM | POLLWRBAND);
1760
1761 if (msg->msg_name)
1762 unix_copy_addr(msg, skb->sk);
1763
1764 if (size > skb->len)
1765 size = skb->len;
1766 else if (size < skb->len)
1767 msg->msg_flags |= MSG_TRUNC;
1768
1769 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1770 if (err)
1771 goto out_free;
1772
1773 if (sock_flag(sk, SOCK_RCVTSTAMP))
1774 __sock_recv_timestamp(msg, sk, skb);
1775
1776 if (!siocb->scm) {
1777 siocb->scm = &tmp_scm;
1778 memset(&tmp_scm, 0, sizeof(tmp_scm));
1779 }
1780 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1781 unix_set_secdata(siocb->scm, skb);
1782
1783 if (!(flags & MSG_PEEK)) {
1784 if (UNIXCB(skb).fp)
1785 unix_detach_fds(siocb->scm, skb);
1786 } else {
1787 /* It is questionable: on PEEK we could:
1788 - do not return fds - good, but too simple 8)
1789 - return fds, and do not return them on read (old strategy,
1790 apparently wrong)
1791 - clone fds (I chose it for now, it is the most universal
1792 solution)
1793
1794 POSIX 1003.1g does not actually define this clearly
1795 at all. POSIX 1003.1g doesn't define a lot of things
1796 clearly however!
1797
1798 */
1799 if (UNIXCB(skb).fp)
1800 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1801 }
1802 err = size;
1803
1804 scm_recv(sock, msg, siocb->scm, flags);
1805
1806out_free:
1807 skb_free_datagram(sk, skb);
1808out_unlock:
1809 mutex_unlock(&u->readlock);
1810out:
1811 return err;
1812}
1813
1814/*
1815 * Sleep until data has arrive. But check for races..
1816 */
1817
1818static long unix_stream_data_wait(struct sock *sk, long timeo)
1819{
1820 DEFINE_WAIT(wait);
1821
1822 unix_state_lock(sk);
1823
1824 for (;;) {
1825 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1826
1827 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1828 sk->sk_err ||
1829 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1830 signal_pending(current) ||
1831 !timeo)
1832 break;
1833
1834 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1835 unix_state_unlock(sk);
1836 timeo = schedule_timeout(timeo);
1837 unix_state_lock(sk);
1838 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1839 }
1840
1841 finish_wait(sk_sleep(sk), &wait);
1842 unix_state_unlock(sk);
1843 return timeo;
1844}
1845
1846
1847
1848static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1849 struct msghdr *msg, size_t size,
1850 int flags)
1851{
1852 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1853 struct scm_cookie tmp_scm;
1854 struct sock *sk = sock->sk;
1855 struct unix_sock *u = unix_sk(sk);
1856 struct sockaddr_un *sunaddr = msg->msg_name;
1857 int copied = 0;
1858 int check_creds = 0;
1859 int target;
1860 int err = 0;
1861 long timeo;
1862
1863 err = -EINVAL;
1864 if (sk->sk_state != TCP_ESTABLISHED)
1865 goto out;
1866
1867 err = -EOPNOTSUPP;
1868 if (flags&MSG_OOB)
1869 goto out;
1870
1871 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1872 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1873
1874 msg->msg_namelen = 0;
1875
1876 /* Lock the socket to prevent queue disordering
1877 * while sleeps in memcpy_tomsg
1878 */
1879
1880 if (!siocb->scm) {
1881 siocb->scm = &tmp_scm;
1882 memset(&tmp_scm, 0, sizeof(tmp_scm));
1883 }
1884
1885 err = mutex_lock_interruptible(&u->readlock);
1886 if (err) {
1887 err = sock_intr_errno(timeo);
1888 goto out;
1889 }
1890
1891 do {
1892 int chunk;
1893 struct sk_buff *skb;
1894
1895 unix_state_lock(sk);
1896 skb = skb_dequeue(&sk->sk_receive_queue);
1897 if (skb == NULL) {
1898 unix_sk(sk)->recursion_level = 0;
1899 if (copied >= target)
1900 goto unlock;
1901
1902 /*
1903 * POSIX 1003.1g mandates this order.
1904 */
1905
1906 err = sock_error(sk);
1907 if (err)
1908 goto unlock;
1909 if (sk->sk_shutdown & RCV_SHUTDOWN)
1910 goto unlock;
1911
1912 unix_state_unlock(sk);
1913 err = -EAGAIN;
1914 if (!timeo)
1915 break;
1916 mutex_unlock(&u->readlock);
1917
1918 timeo = unix_stream_data_wait(sk, timeo);
1919
1920 if (signal_pending(current)
1921 || mutex_lock_interruptible(&u->readlock)) {
1922 err = sock_intr_errno(timeo);
1923 goto out;
1924 }
1925
1926 continue;
1927 unlock:
1928 unix_state_unlock(sk);
1929 break;
1930 }
1931 unix_state_unlock(sk);
1932
1933 if (check_creds) {
1934 /* Never glue messages from different writers */
1935 if ((UNIXCB(skb).pid != siocb->scm->pid) ||
1936 (UNIXCB(skb).cred != siocb->scm->cred)) {
1937 skb_queue_head(&sk->sk_receive_queue, skb);
1938 break;
1939 }
1940 } else {
1941 /* Copy credentials */
1942 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1943 check_creds = 1;
1944 }
1945
1946 /* Copy address just once */
1947 if (sunaddr) {
1948 unix_copy_addr(msg, skb->sk);
1949 sunaddr = NULL;
1950 }
1951
1952 chunk = min_t(unsigned int, skb->len, size);
1953 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
1954 skb_queue_head(&sk->sk_receive_queue, skb);
1955 if (copied == 0)
1956 copied = -EFAULT;
1957 break;
1958 }
1959 copied += chunk;
1960 size -= chunk;
1961
1962 /* Mark read part of skb as used */
1963 if (!(flags & MSG_PEEK)) {
1964 skb_pull(skb, chunk);
1965
1966 if (UNIXCB(skb).fp)
1967 unix_detach_fds(siocb->scm, skb);
1968
1969 /* put the skb back if we didn't use it up.. */
1970 if (skb->len) {
1971 skb_queue_head(&sk->sk_receive_queue, skb);
1972 break;
1973 }
1974
1975 consume_skb(skb);
1976
1977 if (siocb->scm->fp)
1978 break;
1979 } else {
1980 /* It is questionable, see note in unix_dgram_recvmsg.
1981 */
1982 if (UNIXCB(skb).fp)
1983 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1984
1985 /* put message back and return */
1986 skb_queue_head(&sk->sk_receive_queue, skb);
1987 break;
1988 }
1989 } while (size);
1990
1991 mutex_unlock(&u->readlock);
1992 scm_recv(sock, msg, siocb->scm, flags);
1993out:
1994 return copied ? : err;
1995}
1996
1997static int unix_shutdown(struct socket *sock, int mode)
1998{
1999 struct sock *sk = sock->sk;
2000 struct sock *other;
2001
2002 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
2003
2004 if (!mode)
2005 return 0;
2006
2007 unix_state_lock(sk);
2008 sk->sk_shutdown |= mode;
2009 other = unix_peer(sk);
2010 if (other)
2011 sock_hold(other);
2012 unix_state_unlock(sk);
2013 sk->sk_state_change(sk);
2014
2015 if (other &&
2016 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2017
2018 int peer_mode = 0;
2019
2020 if (mode&RCV_SHUTDOWN)
2021 peer_mode |= SEND_SHUTDOWN;
2022 if (mode&SEND_SHUTDOWN)
2023 peer_mode |= RCV_SHUTDOWN;
2024 unix_state_lock(other);
2025 other->sk_shutdown |= peer_mode;
2026 unix_state_unlock(other);
2027 other->sk_state_change(other);
2028 if (peer_mode == SHUTDOWN_MASK)
2029 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2030 else if (peer_mode & RCV_SHUTDOWN)
2031 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2032 }
2033 if (other)
2034 sock_put(other);
2035
2036 return 0;
2037}
2038
2039static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2040{
2041 struct sock *sk = sock->sk;
2042 long amount = 0;
2043 int err;
2044
2045 switch (cmd) {
2046 case SIOCOUTQ:
2047 amount = sk_wmem_alloc_get(sk);
2048 err = put_user(amount, (int __user *)arg);
2049 break;
2050 case SIOCINQ:
2051 {
2052 struct sk_buff *skb;
2053
2054 if (sk->sk_state == TCP_LISTEN) {
2055 err = -EINVAL;
2056 break;
2057 }
2058
2059 spin_lock(&sk->sk_receive_queue.lock);
2060 if (sk->sk_type == SOCK_STREAM ||
2061 sk->sk_type == SOCK_SEQPACKET) {
2062 skb_queue_walk(&sk->sk_receive_queue, skb)
2063 amount += skb->len;
2064 } else {
2065 skb = skb_peek(&sk->sk_receive_queue);
2066 if (skb)
2067 amount = skb->len;
2068 }
2069 spin_unlock(&sk->sk_receive_queue.lock);
2070 err = put_user(amount, (int __user *)arg);
2071 break;
2072 }
2073
2074 default:
2075 err = -ENOIOCTLCMD;
2076 break;
2077 }
2078 return err;
2079}
2080
2081static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2082{
2083 struct sock *sk = sock->sk;
2084 unsigned int mask;
2085
2086 sock_poll_wait(file, sk_sleep(sk), wait);
2087 mask = 0;
2088
2089 /* exceptional events? */
2090 if (sk->sk_err)
2091 mask |= POLLERR;
2092 if (sk->sk_shutdown == SHUTDOWN_MASK)
2093 mask |= POLLHUP;
2094 if (sk->sk_shutdown & RCV_SHUTDOWN)
2095 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2096
2097 /* readable? */
2098 if (!skb_queue_empty(&sk->sk_receive_queue))
2099 mask |= POLLIN | POLLRDNORM;
2100
2101 /* Connection-based need to check for termination and startup */
2102 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2103 sk->sk_state == TCP_CLOSE)
2104 mask |= POLLHUP;
2105
2106 /*
2107 * we set writable also when the other side has shut down the
2108 * connection. This prevents stuck sockets.
2109 */
2110 if (unix_writable(sk))
2111 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2112
2113 return mask;
2114}
2115
2116static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2117 poll_table *wait)
2118{
2119 struct sock *sk = sock->sk, *other;
2120 unsigned int mask, writable;
2121
2122 sock_poll_wait(file, sk_sleep(sk), wait);
2123 mask = 0;
2124
2125 /* exceptional events? */
2126 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2127 mask |= POLLERR;
2128 if (sk->sk_shutdown & RCV_SHUTDOWN)
2129 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2130 if (sk->sk_shutdown == SHUTDOWN_MASK)
2131 mask |= POLLHUP;
2132
2133 /* readable? */
2134 if (!skb_queue_empty(&sk->sk_receive_queue))
2135 mask |= POLLIN | POLLRDNORM;
2136
2137 /* Connection-based need to check for termination and startup */
2138 if (sk->sk_type == SOCK_SEQPACKET) {
2139 if (sk->sk_state == TCP_CLOSE)
2140 mask |= POLLHUP;
2141 /* connection hasn't started yet? */
2142 if (sk->sk_state == TCP_SYN_SENT)
2143 return mask;
2144 }
2145
2146 /* No write status requested, avoid expensive OUT tests. */
2147 if (wait && !(wait->key & (POLLWRBAND | POLLWRNORM | POLLOUT)))
2148 return mask;
2149
2150 writable = unix_writable(sk);
2151 other = unix_peer_get(sk);
2152 if (other) {
2153 if (unix_peer(other) != sk) {
2154 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
2155 if (unix_recvq_full(other))
2156 writable = 0;
2157 }
2158 sock_put(other);
2159 }
2160
2161 if (writable)
2162 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2163 else
2164 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2165
2166 return mask;
2167}
2168
2169#ifdef CONFIG_PROC_FS
2170static struct sock *first_unix_socket(int *i)
2171{
2172 for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2173 if (!hlist_empty(&unix_socket_table[*i]))
2174 return __sk_head(&unix_socket_table[*i]);
2175 }
2176 return NULL;
2177}
2178
2179static struct sock *next_unix_socket(int *i, struct sock *s)
2180{
2181 struct sock *next = sk_next(s);
2182 /* More in this chain? */
2183 if (next)
2184 return next;
2185 /* Look for next non-empty chain. */
2186 for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2187 if (!hlist_empty(&unix_socket_table[*i]))
2188 return __sk_head(&unix_socket_table[*i]);
2189 }
2190 return NULL;
2191}
2192
2193struct unix_iter_state {
2194 struct seq_net_private p;
2195 int i;
2196};
2197
2198static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2199{
2200 struct unix_iter_state *iter = seq->private;
2201 loff_t off = 0;
2202 struct sock *s;
2203
2204 for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2205 if (sock_net(s) != seq_file_net(seq))
2206 continue;
2207 if (off == pos)
2208 return s;
2209 ++off;
2210 }
2211 return NULL;
2212}
2213
2214static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2215 __acquires(unix_table_lock)
2216{
2217 spin_lock(&unix_table_lock);
2218 return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2219}
2220
2221static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2222{
2223 struct unix_iter_state *iter = seq->private;
2224 struct sock *sk = v;
2225 ++*pos;
2226
2227 if (v == SEQ_START_TOKEN)
2228 sk = first_unix_socket(&iter->i);
2229 else
2230 sk = next_unix_socket(&iter->i, sk);
2231 while (sk && (sock_net(sk) != seq_file_net(seq)))
2232 sk = next_unix_socket(&iter->i, sk);
2233 return sk;
2234}
2235
2236static void unix_seq_stop(struct seq_file *seq, void *v)
2237 __releases(unix_table_lock)
2238{
2239 spin_unlock(&unix_table_lock);
2240}
2241
2242static int unix_seq_show(struct seq_file *seq, void *v)
2243{
2244
2245 if (v == SEQ_START_TOKEN)
2246 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2247 "Inode Path\n");
2248 else {
2249 struct sock *s = v;
2250 struct unix_sock *u = unix_sk(s);
2251 unix_state_lock(s);
2252
2253 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2254 s,
2255 atomic_read(&s->sk_refcnt),
2256 0,
2257 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2258 s->sk_type,
2259 s->sk_socket ?
2260 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2261 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2262 sock_i_ino(s));
2263
2264 if (u->addr) {
2265 int i, len;
2266 seq_putc(seq, ' ');
2267
2268 i = 0;
2269 len = u->addr->len - sizeof(short);
2270 if (!UNIX_ABSTRACT(s))
2271 len--;
2272 else {
2273 seq_putc(seq, '@');
2274 i++;
2275 }
2276 for ( ; i < len; i++)
2277 seq_putc(seq, u->addr->name->sun_path[i]);
2278 }
2279 unix_state_unlock(s);
2280 seq_putc(seq, '\n');
2281 }
2282
2283 return 0;
2284}
2285
2286static const struct seq_operations unix_seq_ops = {
2287 .start = unix_seq_start,
2288 .next = unix_seq_next,
2289 .stop = unix_seq_stop,
2290 .show = unix_seq_show,
2291};
2292
2293static int unix_seq_open(struct inode *inode, struct file *file)
2294{
2295 return seq_open_net(inode, file, &unix_seq_ops,
2296 sizeof(struct unix_iter_state));
2297}
2298
2299static const struct file_operations unix_seq_fops = {
2300 .owner = THIS_MODULE,
2301 .open = unix_seq_open,
2302 .read = seq_read,
2303 .llseek = seq_lseek,
2304 .release = seq_release_net,
2305};
2306
2307#endif
2308
2309static const struct net_proto_family unix_family_ops = {
2310 .family = PF_UNIX,
2311 .create = unix_create,
2312 .owner = THIS_MODULE,
2313};
2314
2315
2316static int __net_init unix_net_init(struct net *net)
2317{
2318 int error = -ENOMEM;
2319
2320 net->unx.sysctl_max_dgram_qlen = 10;
2321 if (unix_sysctl_register(net))
2322 goto out;
2323
2324#ifdef CONFIG_PROC_FS
2325 if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2326 unix_sysctl_unregister(net);
2327 goto out;
2328 }
2329#endif
2330 error = 0;
2331out:
2332 return error;
2333}
2334
2335static void __net_exit unix_net_exit(struct net *net)
2336{
2337 unix_sysctl_unregister(net);
2338 proc_net_remove(net, "unix");
2339}
2340
2341static struct pernet_operations unix_net_ops = {
2342 .init = unix_net_init,
2343 .exit = unix_net_exit,
2344};
2345
2346static int __init af_unix_init(void)
2347{
2348 int rc = -1;
2349 struct sk_buff *dummy_skb;
2350
2351 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2352
2353 rc = proto_register(&unix_proto, 1);
2354 if (rc != 0) {
2355 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2356 __func__);
2357 goto out;
2358 }
2359
2360 sock_register(&unix_family_ops);
2361 register_pernet_subsys(&unix_net_ops);
2362out:
2363 return rc;
2364}
2365
2366static void __exit af_unix_exit(void)
2367{
2368 sock_unregister(PF_UNIX);
2369 proto_unregister(&unix_proto);
2370 unregister_pernet_subsys(&unix_net_ops);
2371}
2372
2373/* Earlier than device_initcall() so that other drivers invoking
2374 request_module() don't end up in a loop when modprobe tries
2375 to use a UNIX socket. But later than subsys_initcall() because
2376 we depend on stuff initialised there */
2377fs_initcall(af_unix_init);
2378module_exit(af_unix_exit);
2379
2380MODULE_LICENSE("GPL");
2381MODULE_ALIAS_NETPROTO(PF_UNIX);