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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
84
85#include <linux/module.h>
86#include <linux/kernel.h>
87#include <linux/signal.h>
88#include <linux/sched.h>
89#include <linux/errno.h>
90#include <linux/string.h>
91#include <linux/stat.h>
92#include <linux/dcache.h>
93#include <linux/namei.h>
94#include <linux/socket.h>
95#include <linux/un.h>
96#include <linux/fcntl.h>
97#include <linux/termios.h>
98#include <linux/sockios.h>
99#include <linux/net.h>
100#include <linux/in.h>
101#include <linux/fs.h>
102#include <linux/slab.h>
103#include <asm/uaccess.h>
104#include <linux/skbuff.h>
105#include <linux/netdevice.h>
106#include <net/net_namespace.h>
107#include <net/sock.h>
108#include <net/tcp_states.h>
109#include <net/af_unix.h>
110#include <linux/proc_fs.h>
111#include <linux/seq_file.h>
112#include <net/scm.h>
113#include <linux/init.h>
114#include <linux/poll.h>
115#include <linux/rtnetlink.h>
116#include <linux/mount.h>
117#include <net/checksum.h>
118#include <linux/security.h>
119#include <linux/freezer.h>
120
121struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
122EXPORT_SYMBOL_GPL(unix_socket_table);
123DEFINE_SPINLOCK(unix_table_lock);
124EXPORT_SYMBOL_GPL(unix_table_lock);
125static atomic_long_t unix_nr_socks;
126
127
128static struct hlist_head *unix_sockets_unbound(void *addr)
129{
130 unsigned long hash = (unsigned long)addr;
131
132 hash ^= hash >> 16;
133 hash ^= hash >> 8;
134 hash %= UNIX_HASH_SIZE;
135 return &unix_socket_table[UNIX_HASH_SIZE + hash];
136}
137
138#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
139
140#ifdef CONFIG_SECURITY_NETWORK
141static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
142{
143 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
144}
145
146static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
147{
148 scm->secid = *UNIXSID(skb);
149}
150#else
151static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
152{ }
153
154static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
155{ }
156#endif /* CONFIG_SECURITY_NETWORK */
157
158/*
159 * SMP locking strategy:
160 * hash table is protected with spinlock unix_table_lock
161 * each socket state is protected by separate spin lock.
162 */
163
164static inline unsigned int unix_hash_fold(__wsum n)
165{
166 unsigned int hash = (__force unsigned int)csum_fold(n);
167
168 hash ^= hash>>8;
169 return hash&(UNIX_HASH_SIZE-1);
170}
171
172#define unix_peer(sk) (unix_sk(sk)->peer)
173
174static inline int unix_our_peer(struct sock *sk, struct sock *osk)
175{
176 return unix_peer(osk) == sk;
177}
178
179static inline int unix_may_send(struct sock *sk, struct sock *osk)
180{
181 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
182}
183
184static inline int unix_recvq_full(struct sock const *sk)
185{
186 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
187}
188
189struct sock *unix_peer_get(struct sock *s)
190{
191 struct sock *peer;
192
193 unix_state_lock(s);
194 peer = unix_peer(s);
195 if (peer)
196 sock_hold(peer);
197 unix_state_unlock(s);
198 return peer;
199}
200EXPORT_SYMBOL_GPL(unix_peer_get);
201
202static inline void unix_release_addr(struct unix_address *addr)
203{
204 if (atomic_dec_and_test(&addr->refcnt))
205 kfree(addr);
206}
207
208/*
209 * Check unix socket name:
210 * - should be not zero length.
211 * - if started by not zero, should be NULL terminated (FS object)
212 * - if started by zero, it is abstract name.
213 */
214
215static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
216{
217 if (len <= sizeof(short) || len > sizeof(*sunaddr))
218 return -EINVAL;
219 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
220 return -EINVAL;
221 if (sunaddr->sun_path[0]) {
222 /*
223 * This may look like an off by one error but it is a bit more
224 * subtle. 108 is the longest valid AF_UNIX path for a binding.
225 * sun_path[108] doesn't as such exist. However in kernel space
226 * we are guaranteed that it is a valid memory location in our
227 * kernel address buffer.
228 */
229 ((char *)sunaddr)[len] = 0;
230 len = strlen(sunaddr->sun_path)+1+sizeof(short);
231 return len;
232 }
233
234 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
235 return len;
236}
237
238static void __unix_remove_socket(struct sock *sk)
239{
240 sk_del_node_init(sk);
241}
242
243static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
244{
245 WARN_ON(!sk_unhashed(sk));
246 sk_add_node(sk, list);
247}
248
249static inline void unix_remove_socket(struct sock *sk)
250{
251 spin_lock(&unix_table_lock);
252 __unix_remove_socket(sk);
253 spin_unlock(&unix_table_lock);
254}
255
256static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
257{
258 spin_lock(&unix_table_lock);
259 __unix_insert_socket(list, sk);
260 spin_unlock(&unix_table_lock);
261}
262
263static struct sock *__unix_find_socket_byname(struct net *net,
264 struct sockaddr_un *sunname,
265 int len, int type, unsigned int hash)
266{
267 struct sock *s;
268
269 sk_for_each(s, &unix_socket_table[hash ^ type]) {
270 struct unix_sock *u = unix_sk(s);
271
272 if (!net_eq(sock_net(s), net))
273 continue;
274
275 if (u->addr->len == len &&
276 !memcmp(u->addr->name, sunname, len))
277 goto found;
278 }
279 s = NULL;
280found:
281 return s;
282}
283
284static inline struct sock *unix_find_socket_byname(struct net *net,
285 struct sockaddr_un *sunname,
286 int len, int type,
287 unsigned int hash)
288{
289 struct sock *s;
290
291 spin_lock(&unix_table_lock);
292 s = __unix_find_socket_byname(net, sunname, len, type, hash);
293 if (s)
294 sock_hold(s);
295 spin_unlock(&unix_table_lock);
296 return s;
297}
298
299static struct sock *unix_find_socket_byinode(struct inode *i)
300{
301 struct sock *s;
302
303 spin_lock(&unix_table_lock);
304 sk_for_each(s,
305 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
306 struct dentry *dentry = unix_sk(s)->path.dentry;
307
308 if (dentry && dentry->d_inode == i) {
309 sock_hold(s);
310 goto found;
311 }
312 }
313 s = NULL;
314found:
315 spin_unlock(&unix_table_lock);
316 return s;
317}
318
319static inline int unix_writable(struct sock *sk)
320{
321 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
322}
323
324static void unix_write_space(struct sock *sk)
325{
326 struct socket_wq *wq;
327
328 rcu_read_lock();
329 if (unix_writable(sk)) {
330 wq = rcu_dereference(sk->sk_wq);
331 if (wq_has_sleeper(wq))
332 wake_up_interruptible_sync_poll(&wq->wait,
333 POLLOUT | POLLWRNORM | POLLWRBAND);
334 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
335 }
336 rcu_read_unlock();
337}
338
339/* When dgram socket disconnects (or changes its peer), we clear its receive
340 * queue of packets arrived from previous peer. First, it allows to do
341 * flow control based only on wmem_alloc; second, sk connected to peer
342 * may receive messages only from that peer. */
343static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
344{
345 if (!skb_queue_empty(&sk->sk_receive_queue)) {
346 skb_queue_purge(&sk->sk_receive_queue);
347 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
348
349 /* If one link of bidirectional dgram pipe is disconnected,
350 * we signal error. Messages are lost. Do not make this,
351 * when peer was not connected to us.
352 */
353 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
354 other->sk_err = ECONNRESET;
355 other->sk_error_report(other);
356 }
357 }
358}
359
360static void unix_sock_destructor(struct sock *sk)
361{
362 struct unix_sock *u = unix_sk(sk);
363
364 skb_queue_purge(&sk->sk_receive_queue);
365
366 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
367 WARN_ON(!sk_unhashed(sk));
368 WARN_ON(sk->sk_socket);
369 if (!sock_flag(sk, SOCK_DEAD)) {
370 pr_info("Attempt to release alive unix socket: %p\n", sk);
371 return;
372 }
373
374 if (u->addr)
375 unix_release_addr(u->addr);
376
377 atomic_long_dec(&unix_nr_socks);
378 local_bh_disable();
379 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
380 local_bh_enable();
381#ifdef UNIX_REFCNT_DEBUG
382 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
383 atomic_long_read(&unix_nr_socks));
384#endif
385}
386
387static void unix_release_sock(struct sock *sk, int embrion)
388{
389 struct unix_sock *u = unix_sk(sk);
390 struct path path;
391 struct sock *skpair;
392 struct sk_buff *skb;
393 int state;
394
395 unix_remove_socket(sk);
396
397 /* Clear state */
398 unix_state_lock(sk);
399 sock_orphan(sk);
400 sk->sk_shutdown = SHUTDOWN_MASK;
401 path = u->path;
402 u->path.dentry = NULL;
403 u->path.mnt = NULL;
404 state = sk->sk_state;
405 sk->sk_state = TCP_CLOSE;
406 unix_state_unlock(sk);
407
408 wake_up_interruptible_all(&u->peer_wait);
409
410 skpair = unix_peer(sk);
411
412 if (skpair != NULL) {
413 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
414 unix_state_lock(skpair);
415 /* No more writes */
416 skpair->sk_shutdown = SHUTDOWN_MASK;
417 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
418 skpair->sk_err = ECONNRESET;
419 unix_state_unlock(skpair);
420 skpair->sk_state_change(skpair);
421 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
422 }
423 sock_put(skpair); /* It may now die */
424 unix_peer(sk) = NULL;
425 }
426
427 /* Try to flush out this socket. Throw out buffers at least */
428
429 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
430 if (state == TCP_LISTEN)
431 unix_release_sock(skb->sk, 1);
432 /* passed fds are erased in the kfree_skb hook */
433 kfree_skb(skb);
434 }
435
436 if (path.dentry)
437 path_put(&path);
438
439 sock_put(sk);
440
441 /* ---- Socket is dead now and most probably destroyed ---- */
442
443 /*
444 * Fixme: BSD difference: In BSD all sockets connected to us get
445 * ECONNRESET and we die on the spot. In Linux we behave
446 * like files and pipes do and wait for the last
447 * dereference.
448 *
449 * Can't we simply set sock->err?
450 *
451 * What the above comment does talk about? --ANK(980817)
452 */
453
454 if (unix_tot_inflight)
455 unix_gc(); /* Garbage collect fds */
456}
457
458static void init_peercred(struct sock *sk)
459{
460 put_pid(sk->sk_peer_pid);
461 if (sk->sk_peer_cred)
462 put_cred(sk->sk_peer_cred);
463 sk->sk_peer_pid = get_pid(task_tgid(current));
464 sk->sk_peer_cred = get_current_cred();
465}
466
467static void copy_peercred(struct sock *sk, struct sock *peersk)
468{
469 put_pid(sk->sk_peer_pid);
470 if (sk->sk_peer_cred)
471 put_cred(sk->sk_peer_cred);
472 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
473 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
474}
475
476static int unix_listen(struct socket *sock, int backlog)
477{
478 int err;
479 struct sock *sk = sock->sk;
480 struct unix_sock *u = unix_sk(sk);
481 struct pid *old_pid = NULL;
482
483 err = -EOPNOTSUPP;
484 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
485 goto out; /* Only stream/seqpacket sockets accept */
486 err = -EINVAL;
487 if (!u->addr)
488 goto out; /* No listens on an unbound socket */
489 unix_state_lock(sk);
490 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
491 goto out_unlock;
492 if (backlog > sk->sk_max_ack_backlog)
493 wake_up_interruptible_all(&u->peer_wait);
494 sk->sk_max_ack_backlog = backlog;
495 sk->sk_state = TCP_LISTEN;
496 /* set credentials so connect can copy them */
497 init_peercred(sk);
498 err = 0;
499
500out_unlock:
501 unix_state_unlock(sk);
502 put_pid(old_pid);
503out:
504 return err;
505}
506
507static int unix_release(struct socket *);
508static int unix_bind(struct socket *, struct sockaddr *, int);
509static int unix_stream_connect(struct socket *, struct sockaddr *,
510 int addr_len, int flags);
511static int unix_socketpair(struct socket *, struct socket *);
512static int unix_accept(struct socket *, struct socket *, int);
513static int unix_getname(struct socket *, struct sockaddr *, int *, int);
514static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
515static unsigned int unix_dgram_poll(struct file *, struct socket *,
516 poll_table *);
517static int unix_ioctl(struct socket *, unsigned int, unsigned long);
518static int unix_shutdown(struct socket *, int);
519static int unix_stream_sendmsg(struct kiocb *, struct socket *,
520 struct msghdr *, size_t);
521static int unix_stream_recvmsg(struct kiocb *, struct socket *,
522 struct msghdr *, size_t, int);
523static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
524 struct msghdr *, size_t);
525static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
526 struct msghdr *, size_t, int);
527static int unix_dgram_connect(struct socket *, struct sockaddr *,
528 int, int);
529static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
530 struct msghdr *, size_t);
531static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
532 struct msghdr *, size_t, int);
533
534static int unix_set_peek_off(struct sock *sk, int val)
535{
536 struct unix_sock *u = unix_sk(sk);
537
538 if (mutex_lock_interruptible(&u->readlock))
539 return -EINTR;
540
541 sk->sk_peek_off = val;
542 mutex_unlock(&u->readlock);
543
544 return 0;
545}
546
547
548static const struct proto_ops unix_stream_ops = {
549 .family = PF_UNIX,
550 .owner = THIS_MODULE,
551 .release = unix_release,
552 .bind = unix_bind,
553 .connect = unix_stream_connect,
554 .socketpair = unix_socketpair,
555 .accept = unix_accept,
556 .getname = unix_getname,
557 .poll = unix_poll,
558 .ioctl = unix_ioctl,
559 .listen = unix_listen,
560 .shutdown = unix_shutdown,
561 .setsockopt = sock_no_setsockopt,
562 .getsockopt = sock_no_getsockopt,
563 .sendmsg = unix_stream_sendmsg,
564 .recvmsg = unix_stream_recvmsg,
565 .mmap = sock_no_mmap,
566 .sendpage = sock_no_sendpage,
567 .set_peek_off = unix_set_peek_off,
568};
569
570static const struct proto_ops unix_dgram_ops = {
571 .family = PF_UNIX,
572 .owner = THIS_MODULE,
573 .release = unix_release,
574 .bind = unix_bind,
575 .connect = unix_dgram_connect,
576 .socketpair = unix_socketpair,
577 .accept = sock_no_accept,
578 .getname = unix_getname,
579 .poll = unix_dgram_poll,
580 .ioctl = unix_ioctl,
581 .listen = sock_no_listen,
582 .shutdown = unix_shutdown,
583 .setsockopt = sock_no_setsockopt,
584 .getsockopt = sock_no_getsockopt,
585 .sendmsg = unix_dgram_sendmsg,
586 .recvmsg = unix_dgram_recvmsg,
587 .mmap = sock_no_mmap,
588 .sendpage = sock_no_sendpage,
589 .set_peek_off = unix_set_peek_off,
590};
591
592static const struct proto_ops unix_seqpacket_ops = {
593 .family = PF_UNIX,
594 .owner = THIS_MODULE,
595 .release = unix_release,
596 .bind = unix_bind,
597 .connect = unix_stream_connect,
598 .socketpair = unix_socketpair,
599 .accept = unix_accept,
600 .getname = unix_getname,
601 .poll = unix_dgram_poll,
602 .ioctl = unix_ioctl,
603 .listen = unix_listen,
604 .shutdown = unix_shutdown,
605 .setsockopt = sock_no_setsockopt,
606 .getsockopt = sock_no_getsockopt,
607 .sendmsg = unix_seqpacket_sendmsg,
608 .recvmsg = unix_seqpacket_recvmsg,
609 .mmap = sock_no_mmap,
610 .sendpage = sock_no_sendpage,
611 .set_peek_off = unix_set_peek_off,
612};
613
614static struct proto unix_proto = {
615 .name = "UNIX",
616 .owner = THIS_MODULE,
617 .obj_size = sizeof(struct unix_sock),
618};
619
620/*
621 * AF_UNIX sockets do not interact with hardware, hence they
622 * dont trigger interrupts - so it's safe for them to have
623 * bh-unsafe locking for their sk_receive_queue.lock. Split off
624 * this special lock-class by reinitializing the spinlock key:
625 */
626static struct lock_class_key af_unix_sk_receive_queue_lock_key;
627
628static struct sock *unix_create1(struct net *net, struct socket *sock)
629{
630 struct sock *sk = NULL;
631 struct unix_sock *u;
632
633 atomic_long_inc(&unix_nr_socks);
634 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
635 goto out;
636
637 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
638 if (!sk)
639 goto out;
640
641 sock_init_data(sock, sk);
642 lockdep_set_class(&sk->sk_receive_queue.lock,
643 &af_unix_sk_receive_queue_lock_key);
644
645 sk->sk_write_space = unix_write_space;
646 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
647 sk->sk_destruct = unix_sock_destructor;
648 u = unix_sk(sk);
649 u->path.dentry = NULL;
650 u->path.mnt = NULL;
651 spin_lock_init(&u->lock);
652 atomic_long_set(&u->inflight, 0);
653 INIT_LIST_HEAD(&u->link);
654 mutex_init(&u->readlock); /* single task reading lock */
655 init_waitqueue_head(&u->peer_wait);
656 unix_insert_socket(unix_sockets_unbound(sk), sk);
657out:
658 if (sk == NULL)
659 atomic_long_dec(&unix_nr_socks);
660 else {
661 local_bh_disable();
662 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
663 local_bh_enable();
664 }
665 return sk;
666}
667
668static int unix_create(struct net *net, struct socket *sock, int protocol,
669 int kern)
670{
671 if (protocol && protocol != PF_UNIX)
672 return -EPROTONOSUPPORT;
673
674 sock->state = SS_UNCONNECTED;
675
676 switch (sock->type) {
677 case SOCK_STREAM:
678 sock->ops = &unix_stream_ops;
679 break;
680 /*
681 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
682 * nothing uses it.
683 */
684 case SOCK_RAW:
685 sock->type = SOCK_DGRAM;
686 case SOCK_DGRAM:
687 sock->ops = &unix_dgram_ops;
688 break;
689 case SOCK_SEQPACKET:
690 sock->ops = &unix_seqpacket_ops;
691 break;
692 default:
693 return -ESOCKTNOSUPPORT;
694 }
695
696 return unix_create1(net, sock) ? 0 : -ENOMEM;
697}
698
699static int unix_release(struct socket *sock)
700{
701 struct sock *sk = sock->sk;
702
703 if (!sk)
704 return 0;
705
706 unix_release_sock(sk, 0);
707 sock->sk = NULL;
708
709 return 0;
710}
711
712static int unix_autobind(struct socket *sock)
713{
714 struct sock *sk = sock->sk;
715 struct net *net = sock_net(sk);
716 struct unix_sock *u = unix_sk(sk);
717 static u32 ordernum = 1;
718 struct unix_address *addr;
719 int err;
720 unsigned int retries = 0;
721
722 err = mutex_lock_interruptible(&u->readlock);
723 if (err)
724 return err;
725
726 err = 0;
727 if (u->addr)
728 goto out;
729
730 err = -ENOMEM;
731 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
732 if (!addr)
733 goto out;
734
735 addr->name->sun_family = AF_UNIX;
736 atomic_set(&addr->refcnt, 1);
737
738retry:
739 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
740 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
741
742 spin_lock(&unix_table_lock);
743 ordernum = (ordernum+1)&0xFFFFF;
744
745 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
746 addr->hash)) {
747 spin_unlock(&unix_table_lock);
748 /*
749 * __unix_find_socket_byname() may take long time if many names
750 * are already in use.
751 */
752 cond_resched();
753 /* Give up if all names seems to be in use. */
754 if (retries++ == 0xFFFFF) {
755 err = -ENOSPC;
756 kfree(addr);
757 goto out;
758 }
759 goto retry;
760 }
761 addr->hash ^= sk->sk_type;
762
763 __unix_remove_socket(sk);
764 u->addr = addr;
765 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
766 spin_unlock(&unix_table_lock);
767 err = 0;
768
769out: mutex_unlock(&u->readlock);
770 return err;
771}
772
773static struct sock *unix_find_other(struct net *net,
774 struct sockaddr_un *sunname, int len,
775 int type, unsigned int hash, int *error)
776{
777 struct sock *u;
778 struct path path;
779 int err = 0;
780
781 if (sunname->sun_path[0]) {
782 struct inode *inode;
783 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
784 if (err)
785 goto fail;
786 inode = path.dentry->d_inode;
787 err = inode_permission(inode, MAY_WRITE);
788 if (err)
789 goto put_fail;
790
791 err = -ECONNREFUSED;
792 if (!S_ISSOCK(inode->i_mode))
793 goto put_fail;
794 u = unix_find_socket_byinode(inode);
795 if (!u)
796 goto put_fail;
797
798 if (u->sk_type == type)
799 touch_atime(&path);
800
801 path_put(&path);
802
803 err = -EPROTOTYPE;
804 if (u->sk_type != type) {
805 sock_put(u);
806 goto fail;
807 }
808 } else {
809 err = -ECONNREFUSED;
810 u = unix_find_socket_byname(net, sunname, len, type, hash);
811 if (u) {
812 struct dentry *dentry;
813 dentry = unix_sk(u)->path.dentry;
814 if (dentry)
815 touch_atime(&unix_sk(u)->path);
816 } else
817 goto fail;
818 }
819 return u;
820
821put_fail:
822 path_put(&path);
823fail:
824 *error = err;
825 return NULL;
826}
827
828static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
829{
830 struct dentry *dentry;
831 struct path path;
832 int err = 0;
833 /*
834 * Get the parent directory, calculate the hash for last
835 * component.
836 */
837 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
838 err = PTR_ERR(dentry);
839 if (IS_ERR(dentry))
840 return err;
841
842 /*
843 * All right, let's create it.
844 */
845 err = security_path_mknod(&path, dentry, mode, 0);
846 if (!err) {
847 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
848 if (!err) {
849 res->mnt = mntget(path.mnt);
850 res->dentry = dget(dentry);
851 }
852 }
853 done_path_create(&path, dentry);
854 return err;
855}
856
857static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
858{
859 struct sock *sk = sock->sk;
860 struct net *net = sock_net(sk);
861 struct unix_sock *u = unix_sk(sk);
862 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
863 char *sun_path = sunaddr->sun_path;
864 int err;
865 unsigned int hash;
866 struct unix_address *addr;
867 struct hlist_head *list;
868
869 err = -EINVAL;
870 if (sunaddr->sun_family != AF_UNIX)
871 goto out;
872
873 if (addr_len == sizeof(short)) {
874 err = unix_autobind(sock);
875 goto out;
876 }
877
878 err = unix_mkname(sunaddr, addr_len, &hash);
879 if (err < 0)
880 goto out;
881 addr_len = err;
882
883 err = mutex_lock_interruptible(&u->readlock);
884 if (err)
885 goto out;
886
887 err = -EINVAL;
888 if (u->addr)
889 goto out_up;
890
891 err = -ENOMEM;
892 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
893 if (!addr)
894 goto out_up;
895
896 memcpy(addr->name, sunaddr, addr_len);
897 addr->len = addr_len;
898 addr->hash = hash ^ sk->sk_type;
899 atomic_set(&addr->refcnt, 1);
900
901 if (sun_path[0]) {
902 struct path path;
903 umode_t mode = S_IFSOCK |
904 (SOCK_INODE(sock)->i_mode & ~current_umask());
905 err = unix_mknod(sun_path, mode, &path);
906 if (err) {
907 if (err == -EEXIST)
908 err = -EADDRINUSE;
909 unix_release_addr(addr);
910 goto out_up;
911 }
912 addr->hash = UNIX_HASH_SIZE;
913 hash = path.dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1);
914 spin_lock(&unix_table_lock);
915 u->path = path;
916 list = &unix_socket_table[hash];
917 } else {
918 spin_lock(&unix_table_lock);
919 err = -EADDRINUSE;
920 if (__unix_find_socket_byname(net, sunaddr, addr_len,
921 sk->sk_type, hash)) {
922 unix_release_addr(addr);
923 goto out_unlock;
924 }
925
926 list = &unix_socket_table[addr->hash];
927 }
928
929 err = 0;
930 __unix_remove_socket(sk);
931 u->addr = addr;
932 __unix_insert_socket(list, sk);
933
934out_unlock:
935 spin_unlock(&unix_table_lock);
936out_up:
937 mutex_unlock(&u->readlock);
938out:
939 return err;
940}
941
942static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
943{
944 if (unlikely(sk1 == sk2) || !sk2) {
945 unix_state_lock(sk1);
946 return;
947 }
948 if (sk1 < sk2) {
949 unix_state_lock(sk1);
950 unix_state_lock_nested(sk2);
951 } else {
952 unix_state_lock(sk2);
953 unix_state_lock_nested(sk1);
954 }
955}
956
957static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
958{
959 if (unlikely(sk1 == sk2) || !sk2) {
960 unix_state_unlock(sk1);
961 return;
962 }
963 unix_state_unlock(sk1);
964 unix_state_unlock(sk2);
965}
966
967static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
968 int alen, int flags)
969{
970 struct sock *sk = sock->sk;
971 struct net *net = sock_net(sk);
972 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
973 struct sock *other;
974 unsigned int hash;
975 int err;
976
977 if (addr->sa_family != AF_UNSPEC) {
978 err = unix_mkname(sunaddr, alen, &hash);
979 if (err < 0)
980 goto out;
981 alen = err;
982
983 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
984 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
985 goto out;
986
987restart:
988 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
989 if (!other)
990 goto out;
991
992 unix_state_double_lock(sk, other);
993
994 /* Apparently VFS overslept socket death. Retry. */
995 if (sock_flag(other, SOCK_DEAD)) {
996 unix_state_double_unlock(sk, other);
997 sock_put(other);
998 goto restart;
999 }
1000
1001 err = -EPERM;
1002 if (!unix_may_send(sk, other))
1003 goto out_unlock;
1004
1005 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1006 if (err)
1007 goto out_unlock;
1008
1009 } else {
1010 /*
1011 * 1003.1g breaking connected state with AF_UNSPEC
1012 */
1013 other = NULL;
1014 unix_state_double_lock(sk, other);
1015 }
1016
1017 /*
1018 * If it was connected, reconnect.
1019 */
1020 if (unix_peer(sk)) {
1021 struct sock *old_peer = unix_peer(sk);
1022 unix_peer(sk) = other;
1023 unix_state_double_unlock(sk, other);
1024
1025 if (other != old_peer)
1026 unix_dgram_disconnected(sk, old_peer);
1027 sock_put(old_peer);
1028 } else {
1029 unix_peer(sk) = other;
1030 unix_state_double_unlock(sk, other);
1031 }
1032 return 0;
1033
1034out_unlock:
1035 unix_state_double_unlock(sk, other);
1036 sock_put(other);
1037out:
1038 return err;
1039}
1040
1041static long unix_wait_for_peer(struct sock *other, long timeo)
1042{
1043 struct unix_sock *u = unix_sk(other);
1044 int sched;
1045 DEFINE_WAIT(wait);
1046
1047 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1048
1049 sched = !sock_flag(other, SOCK_DEAD) &&
1050 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1051 unix_recvq_full(other);
1052
1053 unix_state_unlock(other);
1054
1055 if (sched)
1056 timeo = schedule_timeout(timeo);
1057
1058 finish_wait(&u->peer_wait, &wait);
1059 return timeo;
1060}
1061
1062static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1063 int addr_len, int flags)
1064{
1065 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1066 struct sock *sk = sock->sk;
1067 struct net *net = sock_net(sk);
1068 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1069 struct sock *newsk = NULL;
1070 struct sock *other = NULL;
1071 struct sk_buff *skb = NULL;
1072 unsigned int hash;
1073 int st;
1074 int err;
1075 long timeo;
1076
1077 err = unix_mkname(sunaddr, addr_len, &hash);
1078 if (err < 0)
1079 goto out;
1080 addr_len = err;
1081
1082 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1083 (err = unix_autobind(sock)) != 0)
1084 goto out;
1085
1086 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1087
1088 /* First of all allocate resources.
1089 If we will make it after state is locked,
1090 we will have to recheck all again in any case.
1091 */
1092
1093 err = -ENOMEM;
1094
1095 /* create new sock for complete connection */
1096 newsk = unix_create1(sock_net(sk), NULL);
1097 if (newsk == NULL)
1098 goto out;
1099
1100 /* Allocate skb for sending to listening sock */
1101 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1102 if (skb == NULL)
1103 goto out;
1104
1105restart:
1106 /* Find listening sock. */
1107 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1108 if (!other)
1109 goto out;
1110
1111 /* Latch state of peer */
1112 unix_state_lock(other);
1113
1114 /* Apparently VFS overslept socket death. Retry. */
1115 if (sock_flag(other, SOCK_DEAD)) {
1116 unix_state_unlock(other);
1117 sock_put(other);
1118 goto restart;
1119 }
1120
1121 err = -ECONNREFUSED;
1122 if (other->sk_state != TCP_LISTEN)
1123 goto out_unlock;
1124 if (other->sk_shutdown & RCV_SHUTDOWN)
1125 goto out_unlock;
1126
1127 if (unix_recvq_full(other)) {
1128 err = -EAGAIN;
1129 if (!timeo)
1130 goto out_unlock;
1131
1132 timeo = unix_wait_for_peer(other, timeo);
1133
1134 err = sock_intr_errno(timeo);
1135 if (signal_pending(current))
1136 goto out;
1137 sock_put(other);
1138 goto restart;
1139 }
1140
1141 /* Latch our state.
1142
1143 It is tricky place. We need to grab our state lock and cannot
1144 drop lock on peer. It is dangerous because deadlock is
1145 possible. Connect to self case and simultaneous
1146 attempt to connect are eliminated by checking socket
1147 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1148 check this before attempt to grab lock.
1149
1150 Well, and we have to recheck the state after socket locked.
1151 */
1152 st = sk->sk_state;
1153
1154 switch (st) {
1155 case TCP_CLOSE:
1156 /* This is ok... continue with connect */
1157 break;
1158 case TCP_ESTABLISHED:
1159 /* Socket is already connected */
1160 err = -EISCONN;
1161 goto out_unlock;
1162 default:
1163 err = -EINVAL;
1164 goto out_unlock;
1165 }
1166
1167 unix_state_lock_nested(sk);
1168
1169 if (sk->sk_state != st) {
1170 unix_state_unlock(sk);
1171 unix_state_unlock(other);
1172 sock_put(other);
1173 goto restart;
1174 }
1175
1176 err = security_unix_stream_connect(sk, other, newsk);
1177 if (err) {
1178 unix_state_unlock(sk);
1179 goto out_unlock;
1180 }
1181
1182 /* The way is open! Fastly set all the necessary fields... */
1183
1184 sock_hold(sk);
1185 unix_peer(newsk) = sk;
1186 newsk->sk_state = TCP_ESTABLISHED;
1187 newsk->sk_type = sk->sk_type;
1188 init_peercred(newsk);
1189 newu = unix_sk(newsk);
1190 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1191 otheru = unix_sk(other);
1192
1193 /* copy address information from listening to new sock*/
1194 if (otheru->addr) {
1195 atomic_inc(&otheru->addr->refcnt);
1196 newu->addr = otheru->addr;
1197 }
1198 if (otheru->path.dentry) {
1199 path_get(&otheru->path);
1200 newu->path = otheru->path;
1201 }
1202
1203 /* Set credentials */
1204 copy_peercred(sk, other);
1205
1206 sock->state = SS_CONNECTED;
1207 sk->sk_state = TCP_ESTABLISHED;
1208 sock_hold(newsk);
1209
1210 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1211 unix_peer(sk) = newsk;
1212
1213 unix_state_unlock(sk);
1214
1215 /* take ten and and send info to listening sock */
1216 spin_lock(&other->sk_receive_queue.lock);
1217 __skb_queue_tail(&other->sk_receive_queue, skb);
1218 spin_unlock(&other->sk_receive_queue.lock);
1219 unix_state_unlock(other);
1220 other->sk_data_ready(other);
1221 sock_put(other);
1222 return 0;
1223
1224out_unlock:
1225 if (other)
1226 unix_state_unlock(other);
1227
1228out:
1229 kfree_skb(skb);
1230 if (newsk)
1231 unix_release_sock(newsk, 0);
1232 if (other)
1233 sock_put(other);
1234 return err;
1235}
1236
1237static int unix_socketpair(struct socket *socka, struct socket *sockb)
1238{
1239 struct sock *ska = socka->sk, *skb = sockb->sk;
1240
1241 /* Join our sockets back to back */
1242 sock_hold(ska);
1243 sock_hold(skb);
1244 unix_peer(ska) = skb;
1245 unix_peer(skb) = ska;
1246 init_peercred(ska);
1247 init_peercred(skb);
1248
1249 if (ska->sk_type != SOCK_DGRAM) {
1250 ska->sk_state = TCP_ESTABLISHED;
1251 skb->sk_state = TCP_ESTABLISHED;
1252 socka->state = SS_CONNECTED;
1253 sockb->state = SS_CONNECTED;
1254 }
1255 return 0;
1256}
1257
1258static void unix_sock_inherit_flags(const struct socket *old,
1259 struct socket *new)
1260{
1261 if (test_bit(SOCK_PASSCRED, &old->flags))
1262 set_bit(SOCK_PASSCRED, &new->flags);
1263 if (test_bit(SOCK_PASSSEC, &old->flags))
1264 set_bit(SOCK_PASSSEC, &new->flags);
1265}
1266
1267static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1268{
1269 struct sock *sk = sock->sk;
1270 struct sock *tsk;
1271 struct sk_buff *skb;
1272 int err;
1273
1274 err = -EOPNOTSUPP;
1275 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1276 goto out;
1277
1278 err = -EINVAL;
1279 if (sk->sk_state != TCP_LISTEN)
1280 goto out;
1281
1282 /* If socket state is TCP_LISTEN it cannot change (for now...),
1283 * so that no locks are necessary.
1284 */
1285
1286 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1287 if (!skb) {
1288 /* This means receive shutdown. */
1289 if (err == 0)
1290 err = -EINVAL;
1291 goto out;
1292 }
1293
1294 tsk = skb->sk;
1295 skb_free_datagram(sk, skb);
1296 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1297
1298 /* attach accepted sock to socket */
1299 unix_state_lock(tsk);
1300 newsock->state = SS_CONNECTED;
1301 unix_sock_inherit_flags(sock, newsock);
1302 sock_graft(tsk, newsock);
1303 unix_state_unlock(tsk);
1304 return 0;
1305
1306out:
1307 return err;
1308}
1309
1310
1311static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1312{
1313 struct sock *sk = sock->sk;
1314 struct unix_sock *u;
1315 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1316 int err = 0;
1317
1318 if (peer) {
1319 sk = unix_peer_get(sk);
1320
1321 err = -ENOTCONN;
1322 if (!sk)
1323 goto out;
1324 err = 0;
1325 } else {
1326 sock_hold(sk);
1327 }
1328
1329 u = unix_sk(sk);
1330 unix_state_lock(sk);
1331 if (!u->addr) {
1332 sunaddr->sun_family = AF_UNIX;
1333 sunaddr->sun_path[0] = 0;
1334 *uaddr_len = sizeof(short);
1335 } else {
1336 struct unix_address *addr = u->addr;
1337
1338 *uaddr_len = addr->len;
1339 memcpy(sunaddr, addr->name, *uaddr_len);
1340 }
1341 unix_state_unlock(sk);
1342 sock_put(sk);
1343out:
1344 return err;
1345}
1346
1347static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1348{
1349 int i;
1350
1351 scm->fp = UNIXCB(skb).fp;
1352 UNIXCB(skb).fp = NULL;
1353
1354 for (i = scm->fp->count-1; i >= 0; i--)
1355 unix_notinflight(scm->fp->fp[i]);
1356}
1357
1358static void unix_destruct_scm(struct sk_buff *skb)
1359{
1360 struct scm_cookie scm;
1361 memset(&scm, 0, sizeof(scm));
1362 scm.pid = UNIXCB(skb).pid;
1363 if (UNIXCB(skb).fp)
1364 unix_detach_fds(&scm, skb);
1365
1366 /* Alas, it calls VFS */
1367 /* So fscking what? fput() had been SMP-safe since the last Summer */
1368 scm_destroy(&scm);
1369 sock_wfree(skb);
1370}
1371
1372#define MAX_RECURSION_LEVEL 4
1373
1374static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1375{
1376 int i;
1377 unsigned char max_level = 0;
1378 int unix_sock_count = 0;
1379
1380 for (i = scm->fp->count - 1; i >= 0; i--) {
1381 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1382
1383 if (sk) {
1384 unix_sock_count++;
1385 max_level = max(max_level,
1386 unix_sk(sk)->recursion_level);
1387 }
1388 }
1389 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1390 return -ETOOMANYREFS;
1391
1392 /*
1393 * Need to duplicate file references for the sake of garbage
1394 * collection. Otherwise a socket in the fps might become a
1395 * candidate for GC while the skb is not yet queued.
1396 */
1397 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1398 if (!UNIXCB(skb).fp)
1399 return -ENOMEM;
1400
1401 if (unix_sock_count) {
1402 for (i = scm->fp->count - 1; i >= 0; i--)
1403 unix_inflight(scm->fp->fp[i]);
1404 }
1405 return max_level;
1406}
1407
1408static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1409{
1410 int err = 0;
1411
1412 UNIXCB(skb).pid = get_pid(scm->pid);
1413 UNIXCB(skb).uid = scm->creds.uid;
1414 UNIXCB(skb).gid = scm->creds.gid;
1415 UNIXCB(skb).fp = NULL;
1416 if (scm->fp && send_fds)
1417 err = unix_attach_fds(scm, skb);
1418
1419 skb->destructor = unix_destruct_scm;
1420 return err;
1421}
1422
1423/*
1424 * Some apps rely on write() giving SCM_CREDENTIALS
1425 * We include credentials if source or destination socket
1426 * asserted SOCK_PASSCRED.
1427 */
1428static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1429 const struct sock *other)
1430{
1431 if (UNIXCB(skb).pid)
1432 return;
1433 if (test_bit(SOCK_PASSCRED, &sock->flags) ||
1434 !other->sk_socket ||
1435 test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
1436 UNIXCB(skb).pid = get_pid(task_tgid(current));
1437 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1438 }
1439}
1440
1441/*
1442 * Send AF_UNIX data.
1443 */
1444
1445static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1446 struct msghdr *msg, size_t len)
1447{
1448 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1449 struct sock *sk = sock->sk;
1450 struct net *net = sock_net(sk);
1451 struct unix_sock *u = unix_sk(sk);
1452 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1453 struct sock *other = NULL;
1454 int namelen = 0; /* fake GCC */
1455 int err;
1456 unsigned int hash;
1457 struct sk_buff *skb;
1458 long timeo;
1459 struct scm_cookie tmp_scm;
1460 int max_level;
1461 int data_len = 0;
1462
1463 if (NULL == siocb->scm)
1464 siocb->scm = &tmp_scm;
1465 wait_for_unix_gc();
1466 err = scm_send(sock, msg, siocb->scm, false);
1467 if (err < 0)
1468 return err;
1469
1470 err = -EOPNOTSUPP;
1471 if (msg->msg_flags&MSG_OOB)
1472 goto out;
1473
1474 if (msg->msg_namelen) {
1475 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1476 if (err < 0)
1477 goto out;
1478 namelen = err;
1479 } else {
1480 sunaddr = NULL;
1481 err = -ENOTCONN;
1482 other = unix_peer_get(sk);
1483 if (!other)
1484 goto out;
1485 }
1486
1487 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1488 && (err = unix_autobind(sock)) != 0)
1489 goto out;
1490
1491 err = -EMSGSIZE;
1492 if (len > sk->sk_sndbuf - 32)
1493 goto out;
1494
1495 if (len > SKB_MAX_ALLOC)
1496 data_len = min_t(size_t,
1497 len - SKB_MAX_ALLOC,
1498 MAX_SKB_FRAGS * PAGE_SIZE);
1499
1500 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1501 msg->msg_flags & MSG_DONTWAIT, &err,
1502 PAGE_ALLOC_COSTLY_ORDER);
1503 if (skb == NULL)
1504 goto out;
1505
1506 err = unix_scm_to_skb(siocb->scm, skb, true);
1507 if (err < 0)
1508 goto out_free;
1509 max_level = err + 1;
1510 unix_get_secdata(siocb->scm, skb);
1511
1512 skb_put(skb, len - data_len);
1513 skb->data_len = data_len;
1514 skb->len = len;
1515 err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 0, len);
1516 if (err)
1517 goto out_free;
1518
1519 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1520
1521restart:
1522 if (!other) {
1523 err = -ECONNRESET;
1524 if (sunaddr == NULL)
1525 goto out_free;
1526
1527 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1528 hash, &err);
1529 if (other == NULL)
1530 goto out_free;
1531 }
1532
1533 if (sk_filter(other, skb) < 0) {
1534 /* Toss the packet but do not return any error to the sender */
1535 err = len;
1536 goto out_free;
1537 }
1538
1539 unix_state_lock(other);
1540 err = -EPERM;
1541 if (!unix_may_send(sk, other))
1542 goto out_unlock;
1543
1544 if (sock_flag(other, SOCK_DEAD)) {
1545 /*
1546 * Check with 1003.1g - what should
1547 * datagram error
1548 */
1549 unix_state_unlock(other);
1550 sock_put(other);
1551
1552 err = 0;
1553 unix_state_lock(sk);
1554 if (unix_peer(sk) == other) {
1555 unix_peer(sk) = NULL;
1556 unix_state_unlock(sk);
1557
1558 unix_dgram_disconnected(sk, other);
1559 sock_put(other);
1560 err = -ECONNREFUSED;
1561 } else {
1562 unix_state_unlock(sk);
1563 }
1564
1565 other = NULL;
1566 if (err)
1567 goto out_free;
1568 goto restart;
1569 }
1570
1571 err = -EPIPE;
1572 if (other->sk_shutdown & RCV_SHUTDOWN)
1573 goto out_unlock;
1574
1575 if (sk->sk_type != SOCK_SEQPACKET) {
1576 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1577 if (err)
1578 goto out_unlock;
1579 }
1580
1581 if (unix_peer(other) != sk && unix_recvq_full(other)) {
1582 if (!timeo) {
1583 err = -EAGAIN;
1584 goto out_unlock;
1585 }
1586
1587 timeo = unix_wait_for_peer(other, timeo);
1588
1589 err = sock_intr_errno(timeo);
1590 if (signal_pending(current))
1591 goto out_free;
1592
1593 goto restart;
1594 }
1595
1596 if (sock_flag(other, SOCK_RCVTSTAMP))
1597 __net_timestamp(skb);
1598 maybe_add_creds(skb, sock, other);
1599 skb_queue_tail(&other->sk_receive_queue, skb);
1600 if (max_level > unix_sk(other)->recursion_level)
1601 unix_sk(other)->recursion_level = max_level;
1602 unix_state_unlock(other);
1603 other->sk_data_ready(other);
1604 sock_put(other);
1605 scm_destroy(siocb->scm);
1606 return len;
1607
1608out_unlock:
1609 unix_state_unlock(other);
1610out_free:
1611 kfree_skb(skb);
1612out:
1613 if (other)
1614 sock_put(other);
1615 scm_destroy(siocb->scm);
1616 return err;
1617}
1618
1619/* We use paged skbs for stream sockets, and limit occupancy to 32768
1620 * bytes, and a minimun of a full page.
1621 */
1622#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1623
1624static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1625 struct msghdr *msg, size_t len)
1626{
1627 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1628 struct sock *sk = sock->sk;
1629 struct sock *other = NULL;
1630 int err, size;
1631 struct sk_buff *skb;
1632 int sent = 0;
1633 struct scm_cookie tmp_scm;
1634 bool fds_sent = false;
1635 int max_level;
1636 int data_len;
1637
1638 if (NULL == siocb->scm)
1639 siocb->scm = &tmp_scm;
1640 wait_for_unix_gc();
1641 err = scm_send(sock, msg, siocb->scm, false);
1642 if (err < 0)
1643 return err;
1644
1645 err = -EOPNOTSUPP;
1646 if (msg->msg_flags&MSG_OOB)
1647 goto out_err;
1648
1649 if (msg->msg_namelen) {
1650 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1651 goto out_err;
1652 } else {
1653 err = -ENOTCONN;
1654 other = unix_peer(sk);
1655 if (!other)
1656 goto out_err;
1657 }
1658
1659 if (sk->sk_shutdown & SEND_SHUTDOWN)
1660 goto pipe_err;
1661
1662 while (sent < len) {
1663 size = len - sent;
1664
1665 /* Keep two messages in the pipe so it schedules better */
1666 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1667
1668 /* allow fallback to order-0 allocations */
1669 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1670
1671 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1672
1673 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1674 msg->msg_flags & MSG_DONTWAIT, &err,
1675 get_order(UNIX_SKB_FRAGS_SZ));
1676 if (!skb)
1677 goto out_err;
1678
1679 /* Only send the fds in the first buffer */
1680 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1681 if (err < 0) {
1682 kfree_skb(skb);
1683 goto out_err;
1684 }
1685 max_level = err + 1;
1686 fds_sent = true;
1687
1688 skb_put(skb, size - data_len);
1689 skb->data_len = data_len;
1690 skb->len = size;
1691 err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov,
1692 sent, size);
1693 if (err) {
1694 kfree_skb(skb);
1695 goto out_err;
1696 }
1697
1698 unix_state_lock(other);
1699
1700 if (sock_flag(other, SOCK_DEAD) ||
1701 (other->sk_shutdown & RCV_SHUTDOWN))
1702 goto pipe_err_free;
1703
1704 maybe_add_creds(skb, sock, other);
1705 skb_queue_tail(&other->sk_receive_queue, skb);
1706 if (max_level > unix_sk(other)->recursion_level)
1707 unix_sk(other)->recursion_level = max_level;
1708 unix_state_unlock(other);
1709 other->sk_data_ready(other);
1710 sent += size;
1711 }
1712
1713 scm_destroy(siocb->scm);
1714 siocb->scm = NULL;
1715
1716 return sent;
1717
1718pipe_err_free:
1719 unix_state_unlock(other);
1720 kfree_skb(skb);
1721pipe_err:
1722 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1723 send_sig(SIGPIPE, current, 0);
1724 err = -EPIPE;
1725out_err:
1726 scm_destroy(siocb->scm);
1727 siocb->scm = NULL;
1728 return sent ? : err;
1729}
1730
1731static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1732 struct msghdr *msg, size_t len)
1733{
1734 int err;
1735 struct sock *sk = sock->sk;
1736
1737 err = sock_error(sk);
1738 if (err)
1739 return err;
1740
1741 if (sk->sk_state != TCP_ESTABLISHED)
1742 return -ENOTCONN;
1743
1744 if (msg->msg_namelen)
1745 msg->msg_namelen = 0;
1746
1747 return unix_dgram_sendmsg(kiocb, sock, msg, len);
1748}
1749
1750static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
1751 struct msghdr *msg, size_t size,
1752 int flags)
1753{
1754 struct sock *sk = sock->sk;
1755
1756 if (sk->sk_state != TCP_ESTABLISHED)
1757 return -ENOTCONN;
1758
1759 return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
1760}
1761
1762static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1763{
1764 struct unix_sock *u = unix_sk(sk);
1765
1766 if (u->addr) {
1767 msg->msg_namelen = u->addr->len;
1768 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1769 }
1770}
1771
1772static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1773 struct msghdr *msg, size_t size,
1774 int flags)
1775{
1776 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1777 struct scm_cookie tmp_scm;
1778 struct sock *sk = sock->sk;
1779 struct unix_sock *u = unix_sk(sk);
1780 int noblock = flags & MSG_DONTWAIT;
1781 struct sk_buff *skb;
1782 int err;
1783 int peeked, skip;
1784
1785 err = -EOPNOTSUPP;
1786 if (flags&MSG_OOB)
1787 goto out;
1788
1789 err = mutex_lock_interruptible(&u->readlock);
1790 if (unlikely(err)) {
1791 /* recvmsg() in non blocking mode is supposed to return -EAGAIN
1792 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
1793 */
1794 err = noblock ? -EAGAIN : -ERESTARTSYS;
1795 goto out;
1796 }
1797
1798 skip = sk_peek_offset(sk, flags);
1799
1800 skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err);
1801 if (!skb) {
1802 unix_state_lock(sk);
1803 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1804 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1805 (sk->sk_shutdown & RCV_SHUTDOWN))
1806 err = 0;
1807 unix_state_unlock(sk);
1808 goto out_unlock;
1809 }
1810
1811 wake_up_interruptible_sync_poll(&u->peer_wait,
1812 POLLOUT | POLLWRNORM | POLLWRBAND);
1813
1814 if (msg->msg_name)
1815 unix_copy_addr(msg, skb->sk);
1816
1817 if (size > skb->len - skip)
1818 size = skb->len - skip;
1819 else if (size < skb->len - skip)
1820 msg->msg_flags |= MSG_TRUNC;
1821
1822 err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size);
1823 if (err)
1824 goto out_free;
1825
1826 if (sock_flag(sk, SOCK_RCVTSTAMP))
1827 __sock_recv_timestamp(msg, sk, skb);
1828
1829 if (!siocb->scm) {
1830 siocb->scm = &tmp_scm;
1831 memset(&tmp_scm, 0, sizeof(tmp_scm));
1832 }
1833 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
1834 unix_set_secdata(siocb->scm, skb);
1835
1836 if (!(flags & MSG_PEEK)) {
1837 if (UNIXCB(skb).fp)
1838 unix_detach_fds(siocb->scm, skb);
1839
1840 sk_peek_offset_bwd(sk, skb->len);
1841 } else {
1842 /* It is questionable: on PEEK we could:
1843 - do not return fds - good, but too simple 8)
1844 - return fds, and do not return them on read (old strategy,
1845 apparently wrong)
1846 - clone fds (I chose it for now, it is the most universal
1847 solution)
1848
1849 POSIX 1003.1g does not actually define this clearly
1850 at all. POSIX 1003.1g doesn't define a lot of things
1851 clearly however!
1852
1853 */
1854
1855 sk_peek_offset_fwd(sk, size);
1856
1857 if (UNIXCB(skb).fp)
1858 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1859 }
1860 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
1861
1862 scm_recv(sock, msg, siocb->scm, flags);
1863
1864out_free:
1865 skb_free_datagram(sk, skb);
1866out_unlock:
1867 mutex_unlock(&u->readlock);
1868out:
1869 return err;
1870}
1871
1872/*
1873 * Sleep until more data has arrived. But check for races..
1874 */
1875static long unix_stream_data_wait(struct sock *sk, long timeo,
1876 struct sk_buff *last)
1877{
1878 DEFINE_WAIT(wait);
1879
1880 unix_state_lock(sk);
1881
1882 for (;;) {
1883 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1884
1885 if (skb_peek_tail(&sk->sk_receive_queue) != last ||
1886 sk->sk_err ||
1887 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1888 signal_pending(current) ||
1889 !timeo)
1890 break;
1891
1892 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1893 unix_state_unlock(sk);
1894 timeo = freezable_schedule_timeout(timeo);
1895 unix_state_lock(sk);
1896 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1897 }
1898
1899 finish_wait(sk_sleep(sk), &wait);
1900 unix_state_unlock(sk);
1901 return timeo;
1902}
1903
1904static unsigned int unix_skb_len(const struct sk_buff *skb)
1905{
1906 return skb->len - UNIXCB(skb).consumed;
1907}
1908
1909static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1910 struct msghdr *msg, size_t size,
1911 int flags)
1912{
1913 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1914 struct scm_cookie tmp_scm;
1915 struct sock *sk = sock->sk;
1916 struct unix_sock *u = unix_sk(sk);
1917 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1918 int copied = 0;
1919 int noblock = flags & MSG_DONTWAIT;
1920 int check_creds = 0;
1921 int target;
1922 int err = 0;
1923 long timeo;
1924 int skip;
1925
1926 err = -EINVAL;
1927 if (sk->sk_state != TCP_ESTABLISHED)
1928 goto out;
1929
1930 err = -EOPNOTSUPP;
1931 if (flags&MSG_OOB)
1932 goto out;
1933
1934 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1935 timeo = sock_rcvtimeo(sk, noblock);
1936
1937 /* Lock the socket to prevent queue disordering
1938 * while sleeps in memcpy_tomsg
1939 */
1940
1941 if (!siocb->scm) {
1942 siocb->scm = &tmp_scm;
1943 memset(&tmp_scm, 0, sizeof(tmp_scm));
1944 }
1945
1946 err = mutex_lock_interruptible(&u->readlock);
1947 if (unlikely(err)) {
1948 /* recvmsg() in non blocking mode is supposed to return -EAGAIN
1949 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
1950 */
1951 err = noblock ? -EAGAIN : -ERESTARTSYS;
1952 goto out;
1953 }
1954
1955 do {
1956 int chunk;
1957 struct sk_buff *skb, *last;
1958
1959 unix_state_lock(sk);
1960 last = skb = skb_peek(&sk->sk_receive_queue);
1961again:
1962 if (skb == NULL) {
1963 unix_sk(sk)->recursion_level = 0;
1964 if (copied >= target)
1965 goto unlock;
1966
1967 /*
1968 * POSIX 1003.1g mandates this order.
1969 */
1970
1971 err = sock_error(sk);
1972 if (err)
1973 goto unlock;
1974 if (sk->sk_shutdown & RCV_SHUTDOWN)
1975 goto unlock;
1976
1977 unix_state_unlock(sk);
1978 err = -EAGAIN;
1979 if (!timeo)
1980 break;
1981 mutex_unlock(&u->readlock);
1982
1983 timeo = unix_stream_data_wait(sk, timeo, last);
1984
1985 if (signal_pending(current)
1986 || mutex_lock_interruptible(&u->readlock)) {
1987 err = sock_intr_errno(timeo);
1988 goto out;
1989 }
1990
1991 continue;
1992 unlock:
1993 unix_state_unlock(sk);
1994 break;
1995 }
1996
1997 skip = sk_peek_offset(sk, flags);
1998 while (skip >= unix_skb_len(skb)) {
1999 skip -= unix_skb_len(skb);
2000 last = skb;
2001 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2002 if (!skb)
2003 goto again;
2004 }
2005
2006 unix_state_unlock(sk);
2007
2008 if (check_creds) {
2009 /* Never glue messages from different writers */
2010 if ((UNIXCB(skb).pid != siocb->scm->pid) ||
2011 !uid_eq(UNIXCB(skb).uid, siocb->scm->creds.uid) ||
2012 !gid_eq(UNIXCB(skb).gid, siocb->scm->creds.gid))
2013 break;
2014 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2015 /* Copy credentials */
2016 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2017 check_creds = 1;
2018 }
2019
2020 /* Copy address just once */
2021 if (sunaddr) {
2022 unix_copy_addr(msg, skb->sk);
2023 sunaddr = NULL;
2024 }
2025
2026 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2027 if (skb_copy_datagram_iovec(skb, UNIXCB(skb).consumed + skip,
2028 msg->msg_iov, chunk)) {
2029 if (copied == 0)
2030 copied = -EFAULT;
2031 break;
2032 }
2033 copied += chunk;
2034 size -= chunk;
2035
2036 /* Mark read part of skb as used */
2037 if (!(flags & MSG_PEEK)) {
2038 UNIXCB(skb).consumed += chunk;
2039
2040 sk_peek_offset_bwd(sk, chunk);
2041
2042 if (UNIXCB(skb).fp)
2043 unix_detach_fds(siocb->scm, skb);
2044
2045 if (unix_skb_len(skb))
2046 break;
2047
2048 skb_unlink(skb, &sk->sk_receive_queue);
2049 consume_skb(skb);
2050
2051 if (siocb->scm->fp)
2052 break;
2053 } else {
2054 /* It is questionable, see note in unix_dgram_recvmsg.
2055 */
2056 if (UNIXCB(skb).fp)
2057 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
2058
2059 sk_peek_offset_fwd(sk, chunk);
2060
2061 break;
2062 }
2063 } while (size);
2064
2065 mutex_unlock(&u->readlock);
2066 scm_recv(sock, msg, siocb->scm, flags);
2067out:
2068 return copied ? : err;
2069}
2070
2071static int unix_shutdown(struct socket *sock, int mode)
2072{
2073 struct sock *sk = sock->sk;
2074 struct sock *other;
2075
2076 if (mode < SHUT_RD || mode > SHUT_RDWR)
2077 return -EINVAL;
2078 /* This maps:
2079 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2080 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2081 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2082 */
2083 ++mode;
2084
2085 unix_state_lock(sk);
2086 sk->sk_shutdown |= mode;
2087 other = unix_peer(sk);
2088 if (other)
2089 sock_hold(other);
2090 unix_state_unlock(sk);
2091 sk->sk_state_change(sk);
2092
2093 if (other &&
2094 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2095
2096 int peer_mode = 0;
2097
2098 if (mode&RCV_SHUTDOWN)
2099 peer_mode |= SEND_SHUTDOWN;
2100 if (mode&SEND_SHUTDOWN)
2101 peer_mode |= RCV_SHUTDOWN;
2102 unix_state_lock(other);
2103 other->sk_shutdown |= peer_mode;
2104 unix_state_unlock(other);
2105 other->sk_state_change(other);
2106 if (peer_mode == SHUTDOWN_MASK)
2107 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2108 else if (peer_mode & RCV_SHUTDOWN)
2109 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2110 }
2111 if (other)
2112 sock_put(other);
2113
2114 return 0;
2115}
2116
2117long unix_inq_len(struct sock *sk)
2118{
2119 struct sk_buff *skb;
2120 long amount = 0;
2121
2122 if (sk->sk_state == TCP_LISTEN)
2123 return -EINVAL;
2124
2125 spin_lock(&sk->sk_receive_queue.lock);
2126 if (sk->sk_type == SOCK_STREAM ||
2127 sk->sk_type == SOCK_SEQPACKET) {
2128 skb_queue_walk(&sk->sk_receive_queue, skb)
2129 amount += unix_skb_len(skb);
2130 } else {
2131 skb = skb_peek(&sk->sk_receive_queue);
2132 if (skb)
2133 amount = skb->len;
2134 }
2135 spin_unlock(&sk->sk_receive_queue.lock);
2136
2137 return amount;
2138}
2139EXPORT_SYMBOL_GPL(unix_inq_len);
2140
2141long unix_outq_len(struct sock *sk)
2142{
2143 return sk_wmem_alloc_get(sk);
2144}
2145EXPORT_SYMBOL_GPL(unix_outq_len);
2146
2147static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2148{
2149 struct sock *sk = sock->sk;
2150 long amount = 0;
2151 int err;
2152
2153 switch (cmd) {
2154 case SIOCOUTQ:
2155 amount = unix_outq_len(sk);
2156 err = put_user(amount, (int __user *)arg);
2157 break;
2158 case SIOCINQ:
2159 amount = unix_inq_len(sk);
2160 if (amount < 0)
2161 err = amount;
2162 else
2163 err = put_user(amount, (int __user *)arg);
2164 break;
2165 default:
2166 err = -ENOIOCTLCMD;
2167 break;
2168 }
2169 return err;
2170}
2171
2172static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2173{
2174 struct sock *sk = sock->sk;
2175 unsigned int mask;
2176
2177 sock_poll_wait(file, sk_sleep(sk), wait);
2178 mask = 0;
2179
2180 /* exceptional events? */
2181 if (sk->sk_err)
2182 mask |= POLLERR;
2183 if (sk->sk_shutdown == SHUTDOWN_MASK)
2184 mask |= POLLHUP;
2185 if (sk->sk_shutdown & RCV_SHUTDOWN)
2186 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2187
2188 /* readable? */
2189 if (!skb_queue_empty(&sk->sk_receive_queue))
2190 mask |= POLLIN | POLLRDNORM;
2191
2192 /* Connection-based need to check for termination and startup */
2193 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2194 sk->sk_state == TCP_CLOSE)
2195 mask |= POLLHUP;
2196
2197 /*
2198 * we set writable also when the other side has shut down the
2199 * connection. This prevents stuck sockets.
2200 */
2201 if (unix_writable(sk))
2202 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2203
2204 return mask;
2205}
2206
2207static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2208 poll_table *wait)
2209{
2210 struct sock *sk = sock->sk, *other;
2211 unsigned int mask, writable;
2212
2213 sock_poll_wait(file, sk_sleep(sk), wait);
2214 mask = 0;
2215
2216 /* exceptional events? */
2217 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2218 mask |= POLLERR |
2219 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2220
2221 if (sk->sk_shutdown & RCV_SHUTDOWN)
2222 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2223 if (sk->sk_shutdown == SHUTDOWN_MASK)
2224 mask |= POLLHUP;
2225
2226 /* readable? */
2227 if (!skb_queue_empty(&sk->sk_receive_queue))
2228 mask |= POLLIN | POLLRDNORM;
2229
2230 /* Connection-based need to check for termination and startup */
2231 if (sk->sk_type == SOCK_SEQPACKET) {
2232 if (sk->sk_state == TCP_CLOSE)
2233 mask |= POLLHUP;
2234 /* connection hasn't started yet? */
2235 if (sk->sk_state == TCP_SYN_SENT)
2236 return mask;
2237 }
2238
2239 /* No write status requested, avoid expensive OUT tests. */
2240 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
2241 return mask;
2242
2243 writable = unix_writable(sk);
2244 other = unix_peer_get(sk);
2245 if (other) {
2246 if (unix_peer(other) != sk) {
2247 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
2248 if (unix_recvq_full(other))
2249 writable = 0;
2250 }
2251 sock_put(other);
2252 }
2253
2254 if (writable)
2255 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2256 else
2257 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2258
2259 return mask;
2260}
2261
2262#ifdef CONFIG_PROC_FS
2263
2264#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2265
2266#define get_bucket(x) ((x) >> BUCKET_SPACE)
2267#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2268#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2269
2270static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2271{
2272 unsigned long offset = get_offset(*pos);
2273 unsigned long bucket = get_bucket(*pos);
2274 struct sock *sk;
2275 unsigned long count = 0;
2276
2277 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2278 if (sock_net(sk) != seq_file_net(seq))
2279 continue;
2280 if (++count == offset)
2281 break;
2282 }
2283
2284 return sk;
2285}
2286
2287static struct sock *unix_next_socket(struct seq_file *seq,
2288 struct sock *sk,
2289 loff_t *pos)
2290{
2291 unsigned long bucket;
2292
2293 while (sk > (struct sock *)SEQ_START_TOKEN) {
2294 sk = sk_next(sk);
2295 if (!sk)
2296 goto next_bucket;
2297 if (sock_net(sk) == seq_file_net(seq))
2298 return sk;
2299 }
2300
2301 do {
2302 sk = unix_from_bucket(seq, pos);
2303 if (sk)
2304 return sk;
2305
2306next_bucket:
2307 bucket = get_bucket(*pos) + 1;
2308 *pos = set_bucket_offset(bucket, 1);
2309 } while (bucket < ARRAY_SIZE(unix_socket_table));
2310
2311 return NULL;
2312}
2313
2314static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2315 __acquires(unix_table_lock)
2316{
2317 spin_lock(&unix_table_lock);
2318
2319 if (!*pos)
2320 return SEQ_START_TOKEN;
2321
2322 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2323 return NULL;
2324
2325 return unix_next_socket(seq, NULL, pos);
2326}
2327
2328static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2329{
2330 ++*pos;
2331 return unix_next_socket(seq, v, pos);
2332}
2333
2334static void unix_seq_stop(struct seq_file *seq, void *v)
2335 __releases(unix_table_lock)
2336{
2337 spin_unlock(&unix_table_lock);
2338}
2339
2340static int unix_seq_show(struct seq_file *seq, void *v)
2341{
2342
2343 if (v == SEQ_START_TOKEN)
2344 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2345 "Inode Path\n");
2346 else {
2347 struct sock *s = v;
2348 struct unix_sock *u = unix_sk(s);
2349 unix_state_lock(s);
2350
2351 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2352 s,
2353 atomic_read(&s->sk_refcnt),
2354 0,
2355 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2356 s->sk_type,
2357 s->sk_socket ?
2358 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2359 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2360 sock_i_ino(s));
2361
2362 if (u->addr) {
2363 int i, len;
2364 seq_putc(seq, ' ');
2365
2366 i = 0;
2367 len = u->addr->len - sizeof(short);
2368 if (!UNIX_ABSTRACT(s))
2369 len--;
2370 else {
2371 seq_putc(seq, '@');
2372 i++;
2373 }
2374 for ( ; i < len; i++)
2375 seq_putc(seq, u->addr->name->sun_path[i]);
2376 }
2377 unix_state_unlock(s);
2378 seq_putc(seq, '\n');
2379 }
2380
2381 return 0;
2382}
2383
2384static const struct seq_operations unix_seq_ops = {
2385 .start = unix_seq_start,
2386 .next = unix_seq_next,
2387 .stop = unix_seq_stop,
2388 .show = unix_seq_show,
2389};
2390
2391static int unix_seq_open(struct inode *inode, struct file *file)
2392{
2393 return seq_open_net(inode, file, &unix_seq_ops,
2394 sizeof(struct seq_net_private));
2395}
2396
2397static const struct file_operations unix_seq_fops = {
2398 .owner = THIS_MODULE,
2399 .open = unix_seq_open,
2400 .read = seq_read,
2401 .llseek = seq_lseek,
2402 .release = seq_release_net,
2403};
2404
2405#endif
2406
2407static const struct net_proto_family unix_family_ops = {
2408 .family = PF_UNIX,
2409 .create = unix_create,
2410 .owner = THIS_MODULE,
2411};
2412
2413
2414static int __net_init unix_net_init(struct net *net)
2415{
2416 int error = -ENOMEM;
2417
2418 net->unx.sysctl_max_dgram_qlen = 10;
2419 if (unix_sysctl_register(net))
2420 goto out;
2421
2422#ifdef CONFIG_PROC_FS
2423 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2424 unix_sysctl_unregister(net);
2425 goto out;
2426 }
2427#endif
2428 error = 0;
2429out:
2430 return error;
2431}
2432
2433static void __net_exit unix_net_exit(struct net *net)
2434{
2435 unix_sysctl_unregister(net);
2436 remove_proc_entry("unix", net->proc_net);
2437}
2438
2439static struct pernet_operations unix_net_ops = {
2440 .init = unix_net_init,
2441 .exit = unix_net_exit,
2442};
2443
2444static int __init af_unix_init(void)
2445{
2446 int rc = -1;
2447
2448 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2449
2450 rc = proto_register(&unix_proto, 1);
2451 if (rc != 0) {
2452 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
2453 goto out;
2454 }
2455
2456 sock_register(&unix_family_ops);
2457 register_pernet_subsys(&unix_net_ops);
2458out:
2459 return rc;
2460}
2461
2462static void __exit af_unix_exit(void)
2463{
2464 sock_unregister(PF_UNIX);
2465 proto_unregister(&unix_proto);
2466 unregister_pernet_subsys(&unix_net_ops);
2467}
2468
2469/* Earlier than device_initcall() so that other drivers invoking
2470 request_module() don't end up in a loop when modprobe tries
2471 to use a UNIX socket. But later than subsys_initcall() because
2472 we depend on stuff initialised there */
2473fs_initcall(af_unix_init);
2474module_exit(af_unix_exit);
2475
2476MODULE_LICENSE("GPL");
2477MODULE_ALIAS_NETPROTO(PF_UNIX);