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> 120 121 struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE]; 122 EXPORT_SYMBOL_GPL(unix_socket_table); 123 DEFINE_SPINLOCK(unix_table_lock); 124 EXPORT_SYMBOL_GPL(unix_table_lock); 125 static atomic_long_t unix_nr_socks; 126 127 128 static 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 141 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 142 { 143 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32)); 144 } 145 146 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 147 { 148 scm->secid = *UNIXSID(skb); 149 } 150 #else 151 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 152 { } 153 154 static 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 */ 163 164 static 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) 173 174 static inline int unix_our_peer(struct sock *sk, struct sock *osk) 175 { 176 return unix_peer(osk) == sk; 177 } 178 179 static inline int unix_may_send(struct sock *sk, struct sock *osk) 180 { 181 return unix_peer(osk) == NULL || unix_our_peer(sk, osk); 182 } 183 184 static 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 } 188 189 struct 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 } 200 EXPORT_SYMBOL_GPL(unix_peer_get); 201 202 static 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 */ 214 215 static 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 } 237 238 static void __unix_remove_socket(struct sock *sk) 239 { 240 sk_del_node_init(sk); 241 } 242 243 static 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 } 248 249 static 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 } 255 256 static 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 } 262 263 static 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; 280 found: 281 return s; 282 } 283 284 static 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 } 298 299 static 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; 314 found: 315 spin_unlock(&unix_table_lock); 316 return s; 317 } 318 319 static inline int unix_writable(struct sock *sk) 320 { 321 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf; 322 } 323 324 static 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. */ 343 static 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 } 359 360 static 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 } 386 387 static 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 } 457 458 static 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 } 466 467 static 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 } 475 476 static 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; 499 500 out_unlock: 501 unix_state_unlock(sk); 502 put_pid(old_pid); 503 out: 504 return err; 505 } 506 507 static int unix_release(struct socket *); 508 static int unix_bind(struct socket *, struct sockaddr *, int); 509 static int unix_stream_connect(struct socket *, struct sockaddr *, 510 int addr_len, int flags); 511 static int unix_socketpair(struct socket *, struct socket *); 512 static int unix_accept(struct socket *, struct socket *, int); 513 static int unix_getname(struct socket *, struct sockaddr *, int *, int); 514 static unsigned int unix_poll(struct file *, struct socket *, poll_table *); 515 static unsigned int unix_dgram_poll(struct file *, struct socket *, 516 poll_table *); 517 static int unix_ioctl(struct socket *, unsigned int, unsigned long); 518 static int unix_shutdown(struct socket *, int); 519 static int unix_stream_sendmsg(struct kiocb *, struct socket *, 520 struct msghdr *, size_t); 521 static int unix_stream_recvmsg(struct kiocb *, struct socket *, 522 struct msghdr *, size_t, int); 523 static int unix_dgram_sendmsg(struct kiocb *, struct socket *, 524 struct msghdr *, size_t); 525 static int unix_dgram_recvmsg(struct kiocb *, struct socket *, 526 struct msghdr *, size_t, int); 527 static int unix_dgram_connect(struct socket *, struct sockaddr *, 528 int, int); 529 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *, 530 struct msghdr *, size_t); 531 static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *, 532 struct msghdr *, size_t, int); 533 534 static 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 } 546 547 548 static 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 }; 569 570 static 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 }; 591 592 static 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 }; 613 614 static 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 */ 626 static struct lock_class_key af_unix_sk_receive_queue_lock_key; 627 628 static 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); 657 out: 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 } 667 668 static 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 } 698 699 static 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 } 711 712 static 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); 737 738 retry: 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; 768 769 out: mutex_unlock(&u->readlock); 770 return err; 771 } 772 773 static 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; 820 821 put_fail: 822 path_put(&path); 823 fail: 824 *error = err; 825 return NULL; 826 } 827 828 static 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 } 856 857 static 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); 933 934 out_unlock: 935 spin_unlock(&unix_table_lock); 936 out_up: 937 mutex_unlock(&u->readlock); 938 out: 939 return err; 940 } 941 942 static 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 } 956 957 static 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 } 966 967 static 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; 986 987 restart: 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 1034 out_unlock: 1035 unix_state_double_unlock(sk, other); 1036 sock_put(other); 1037 out: 1038 return err; 1039 } 1040 1041 static 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 1062 static 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 1105 restart: 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(); /* 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 1224 out_unlock: 1225 if (other) 1226 unix_state_unlock(other); 1227 1228 out: 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 1237 static 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 1258 static 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 1267 static 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 1306 out: 1307 return err; 1308 } 1309 1310 1311 static 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); 1343 out: 1344 return err; 1345 } 1346 1347 static 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 1358 static 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 1374 static 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 1408 static 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 */ 1428 static 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 1445 static 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 data_len = PAGE_ALIGN(data_len); 1500 1501 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE); 1502 } 1503 1504 skb = sock_alloc_send_pskb(sk, len - data_len, data_len, 1505 msg->msg_flags & MSG_DONTWAIT, &err, 1506 PAGE_ALLOC_COSTLY_ORDER); 1507 if (skb == NULL) 1508 goto out; 1509 1510 err = unix_scm_to_skb(siocb->scm, skb, true); 1511 if (err < 0) 1512 goto out_free; 1513 max_level = err + 1; 1514 unix_get_secdata(siocb->scm, skb); 1515 1516 skb_put(skb, len - data_len); 1517 skb->data_len = data_len; 1518 skb->len = len; 1519 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len); 1520 if (err) 1521 goto out_free; 1522 1523 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1524 1525 restart: 1526 if (!other) { 1527 err = -ECONNRESET; 1528 if (sunaddr == NULL) 1529 goto out_free; 1530 1531 other = unix_find_other(net, sunaddr, namelen, sk->sk_type, 1532 hash, &err); 1533 if (other == NULL) 1534 goto out_free; 1535 } 1536 1537 if (sk_filter(other, skb) < 0) { 1538 /* Toss the packet but do not return any error to the sender */ 1539 err = len; 1540 goto out_free; 1541 } 1542 1543 unix_state_lock(other); 1544 err = -EPERM; 1545 if (!unix_may_send(sk, other)) 1546 goto out_unlock; 1547 1548 if (sock_flag(other, SOCK_DEAD)) { 1549 /* 1550 * Check with 1003.1g - what should 1551 * datagram error 1552 */ 1553 unix_state_unlock(other); 1554 sock_put(other); 1555 1556 err = 0; 1557 unix_state_lock(sk); 1558 if (unix_peer(sk) == other) { 1559 unix_peer(sk) = NULL; 1560 unix_state_unlock(sk); 1561 1562 unix_dgram_disconnected(sk, other); 1563 sock_put(other); 1564 err = -ECONNREFUSED; 1565 } else { 1566 unix_state_unlock(sk); 1567 } 1568 1569 other = NULL; 1570 if (err) 1571 goto out_free; 1572 goto restart; 1573 } 1574 1575 err = -EPIPE; 1576 if (other->sk_shutdown & RCV_SHUTDOWN) 1577 goto out_unlock; 1578 1579 if (sk->sk_type != SOCK_SEQPACKET) { 1580 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 1581 if (err) 1582 goto out_unlock; 1583 } 1584 1585 if (unix_peer(other) != sk && unix_recvq_full(other)) { 1586 if (!timeo) { 1587 err = -EAGAIN; 1588 goto out_unlock; 1589 } 1590 1591 timeo = unix_wait_for_peer(other, timeo); 1592 1593 err = sock_intr_errno(timeo); 1594 if (signal_pending(current)) 1595 goto out_free; 1596 1597 goto restart; 1598 } 1599 1600 if (sock_flag(other, SOCK_RCVTSTAMP)) 1601 __net_timestamp(skb); 1602 maybe_add_creds(skb, sock, other); 1603 skb_queue_tail(&other->sk_receive_queue, skb); 1604 if (max_level > unix_sk(other)->recursion_level) 1605 unix_sk(other)->recursion_level = max_level; 1606 unix_state_unlock(other); 1607 other->sk_data_ready(other); 1608 sock_put(other); 1609 scm_destroy(siocb->scm); 1610 return len; 1611 1612 out_unlock: 1613 unix_state_unlock(other); 1614 out_free: 1615 kfree_skb(skb); 1616 out: 1617 if (other) 1618 sock_put(other); 1619 scm_destroy(siocb->scm); 1620 return err; 1621 } 1622 1623 /* We use paged skbs for stream sockets, and limit occupancy to 32768 1624 * bytes, and a minimun of a full page. 1625 */ 1626 #define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768)) 1627 1628 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 1629 struct msghdr *msg, size_t len) 1630 { 1631 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1632 struct sock *sk = sock->sk; 1633 struct sock *other = NULL; 1634 int err, size; 1635 struct sk_buff *skb; 1636 int sent = 0; 1637 struct scm_cookie tmp_scm; 1638 bool fds_sent = false; 1639 int max_level; 1640 int data_len; 1641 1642 if (NULL == siocb->scm) 1643 siocb->scm = &tmp_scm; 1644 wait_for_unix_gc(); 1645 err = scm_send(sock, msg, siocb->scm, false); 1646 if (err < 0) 1647 return err; 1648 1649 err = -EOPNOTSUPP; 1650 if (msg->msg_flags&MSG_OOB) 1651 goto out_err; 1652 1653 if (msg->msg_namelen) { 1654 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; 1655 goto out_err; 1656 } else { 1657 err = -ENOTCONN; 1658 other = unix_peer(sk); 1659 if (!other) 1660 goto out_err; 1661 } 1662 1663 if (sk->sk_shutdown & SEND_SHUTDOWN) 1664 goto pipe_err; 1665 1666 while (sent < len) { 1667 size = len - sent; 1668 1669 /* Keep two messages in the pipe so it schedules better */ 1670 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64); 1671 1672 /* allow fallback to order-0 allocations */ 1673 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ); 1674 1675 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0)); 1676 1677 data_len = min_t(size_t, size, PAGE_ALIGN(data_len)); 1678 1679 skb = sock_alloc_send_pskb(sk, size - data_len, data_len, 1680 msg->msg_flags & MSG_DONTWAIT, &err, 1681 get_order(UNIX_SKB_FRAGS_SZ)); 1682 if (!skb) 1683 goto out_err; 1684 1685 /* Only send the fds in the first buffer */ 1686 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent); 1687 if (err < 0) { 1688 kfree_skb(skb); 1689 goto out_err; 1690 } 1691 max_level = err + 1; 1692 fds_sent = true; 1693 1694 skb_put(skb, size - data_len); 1695 skb->data_len = data_len; 1696 skb->len = size; 1697 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size); 1698 if (err) { 1699 kfree_skb(skb); 1700 goto out_err; 1701 } 1702 1703 unix_state_lock(other); 1704 1705 if (sock_flag(other, SOCK_DEAD) || 1706 (other->sk_shutdown & RCV_SHUTDOWN)) 1707 goto pipe_err_free; 1708 1709 maybe_add_creds(skb, sock, other); 1710 skb_queue_tail(&other->sk_receive_queue, skb); 1711 if (max_level > unix_sk(other)->recursion_level) 1712 unix_sk(other)->recursion_level = max_level; 1713 unix_state_unlock(other); 1714 other->sk_data_ready(other); 1715 sent += size; 1716 } 1717 1718 scm_destroy(siocb->scm); 1719 siocb->scm = NULL; 1720 1721 return sent; 1722 1723 pipe_err_free: 1724 unix_state_unlock(other); 1725 kfree_skb(skb); 1726 pipe_err: 1727 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) 1728 send_sig(SIGPIPE, current, 0); 1729 err = -EPIPE; 1730 out_err: 1731 scm_destroy(siocb->scm); 1732 siocb->scm = NULL; 1733 return sent ? : err; 1734 } 1735 1736 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock, 1737 struct msghdr *msg, size_t len) 1738 { 1739 int err; 1740 struct sock *sk = sock->sk; 1741 1742 err = sock_error(sk); 1743 if (err) 1744 return err; 1745 1746 if (sk->sk_state != TCP_ESTABLISHED) 1747 return -ENOTCONN; 1748 1749 if (msg->msg_namelen) 1750 msg->msg_namelen = 0; 1751 1752 return unix_dgram_sendmsg(kiocb, sock, msg, len); 1753 } 1754 1755 static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock, 1756 struct msghdr *msg, size_t size, 1757 int flags) 1758 { 1759 struct sock *sk = sock->sk; 1760 1761 if (sk->sk_state != TCP_ESTABLISHED) 1762 return -ENOTCONN; 1763 1764 return unix_dgram_recvmsg(iocb, sock, msg, size, flags); 1765 } 1766 1767 static void unix_copy_addr(struct msghdr *msg, struct sock *sk) 1768 { 1769 struct unix_sock *u = unix_sk(sk); 1770 1771 if (u->addr) { 1772 msg->msg_namelen = u->addr->len; 1773 memcpy(msg->msg_name, u->addr->name, u->addr->len); 1774 } 1775 } 1776 1777 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, 1778 struct msghdr *msg, size_t size, 1779 int flags) 1780 { 1781 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1782 struct scm_cookie tmp_scm; 1783 struct sock *sk = sock->sk; 1784 struct unix_sock *u = unix_sk(sk); 1785 int noblock = flags & MSG_DONTWAIT; 1786 struct sk_buff *skb; 1787 int err; 1788 int peeked, skip; 1789 1790 err = -EOPNOTSUPP; 1791 if (flags&MSG_OOB) 1792 goto out; 1793 1794 err = mutex_lock_interruptible(&u->readlock); 1795 if (unlikely(err)) { 1796 /* recvmsg() in non blocking mode is supposed to return -EAGAIN 1797 * sk_rcvtimeo is not honored by mutex_lock_interruptible() 1798 */ 1799 err = noblock ? -EAGAIN : -ERESTARTSYS; 1800 goto out; 1801 } 1802 1803 skip = sk_peek_offset(sk, flags); 1804 1805 skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err); 1806 if (!skb) { 1807 unix_state_lock(sk); 1808 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */ 1809 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN && 1810 (sk->sk_shutdown & RCV_SHUTDOWN)) 1811 err = 0; 1812 unix_state_unlock(sk); 1813 goto out_unlock; 1814 } 1815 1816 wake_up_interruptible_sync_poll(&u->peer_wait, 1817 POLLOUT | POLLWRNORM | POLLWRBAND); 1818 1819 if (msg->msg_name) 1820 unix_copy_addr(msg, skb->sk); 1821 1822 if (size > skb->len - skip) 1823 size = skb->len - skip; 1824 else if (size < skb->len - skip) 1825 msg->msg_flags |= MSG_TRUNC; 1826 1827 err = skb_copy_datagram_msg(skb, skip, msg, size); 1828 if (err) 1829 goto out_free; 1830 1831 if (sock_flag(sk, SOCK_RCVTSTAMP)) 1832 __sock_recv_timestamp(msg, sk, skb); 1833 1834 if (!siocb->scm) { 1835 siocb->scm = &tmp_scm; 1836 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1837 } 1838 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); 1839 unix_set_secdata(siocb->scm, skb); 1840 1841 if (!(flags & MSG_PEEK)) { 1842 if (UNIXCB(skb).fp) 1843 unix_detach_fds(siocb->scm, skb); 1844 1845 sk_peek_offset_bwd(sk, skb->len); 1846 } else { 1847 /* It is questionable: on PEEK we could: 1848 - do not return fds - good, but too simple 8) 1849 - return fds, and do not return them on read (old strategy, 1850 apparently wrong) 1851 - clone fds (I chose it for now, it is the most universal 1852 solution) 1853 1854 POSIX 1003.1g does not actually define this clearly 1855 at all. POSIX 1003.1g doesn't define a lot of things 1856 clearly however! 1857 1858 */ 1859 1860 sk_peek_offset_fwd(sk, size); 1861 1862 if (UNIXCB(skb).fp) 1863 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 1864 } 1865 err = (flags & MSG_TRUNC) ? skb->len - skip : size; 1866 1867 scm_recv(sock, msg, siocb->scm, flags); 1868 1869 out_free: 1870 skb_free_datagram(sk, skb); 1871 out_unlock: 1872 mutex_unlock(&u->readlock); 1873 out: 1874 return err; 1875 } 1876 1877 /* 1878 * Sleep until more data has arrived. But check for races.. 1879 */ 1880 static long unix_stream_data_wait(struct sock *sk, long timeo, 1881 struct sk_buff *last) 1882 { 1883 DEFINE_WAIT(wait); 1884 1885 unix_state_lock(sk); 1886 1887 for (;;) { 1888 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 1889 1890 if (skb_peek_tail(&sk->sk_receive_queue) != last || 1891 sk->sk_err || 1892 (sk->sk_shutdown & RCV_SHUTDOWN) || 1893 signal_pending(current) || 1894 !timeo) 1895 break; 1896 1897 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1898 unix_state_unlock(sk); 1899 timeo = freezable_schedule_timeout(timeo); 1900 unix_state_lock(sk); 1901 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1902 } 1903 1904 finish_wait(sk_sleep(sk), &wait); 1905 unix_state_unlock(sk); 1906 return timeo; 1907 } 1908 1909 static unsigned int unix_skb_len(const struct sk_buff *skb) 1910 { 1911 return skb->len - UNIXCB(skb).consumed; 1912 } 1913 1914 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, 1915 struct msghdr *msg, size_t size, 1916 int flags) 1917 { 1918 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1919 struct scm_cookie tmp_scm; 1920 struct sock *sk = sock->sk; 1921 struct unix_sock *u = unix_sk(sk); 1922 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name); 1923 int copied = 0; 1924 int noblock = flags & MSG_DONTWAIT; 1925 int check_creds = 0; 1926 int target; 1927 int err = 0; 1928 long timeo; 1929 int skip; 1930 1931 err = -EINVAL; 1932 if (sk->sk_state != TCP_ESTABLISHED) 1933 goto out; 1934 1935 err = -EOPNOTSUPP; 1936 if (flags&MSG_OOB) 1937 goto out; 1938 1939 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); 1940 timeo = sock_rcvtimeo(sk, noblock); 1941 1942 /* Lock the socket to prevent queue disordering 1943 * while sleeps in memcpy_tomsg 1944 */ 1945 1946 if (!siocb->scm) { 1947 siocb->scm = &tmp_scm; 1948 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1949 } 1950 1951 err = mutex_lock_interruptible(&u->readlock); 1952 if (unlikely(err)) { 1953 /* recvmsg() in non blocking mode is supposed to return -EAGAIN 1954 * sk_rcvtimeo is not honored by mutex_lock_interruptible() 1955 */ 1956 err = noblock ? -EAGAIN : -ERESTARTSYS; 1957 goto out; 1958 } 1959 1960 do { 1961 int chunk; 1962 struct sk_buff *skb, *last; 1963 1964 unix_state_lock(sk); 1965 last = skb = skb_peek(&sk->sk_receive_queue); 1966 again: 1967 if (skb == NULL) { 1968 unix_sk(sk)->recursion_level = 0; 1969 if (copied >= target) 1970 goto unlock; 1971 1972 /* 1973 * POSIX 1003.1g mandates this order. 1974 */ 1975 1976 err = sock_error(sk); 1977 if (err) 1978 goto unlock; 1979 if (sk->sk_shutdown & RCV_SHUTDOWN) 1980 goto unlock; 1981 1982 unix_state_unlock(sk); 1983 err = -EAGAIN; 1984 if (!timeo) 1985 break; 1986 mutex_unlock(&u->readlock); 1987 1988 timeo = unix_stream_data_wait(sk, timeo, last); 1989 1990 if (signal_pending(current) 1991 || mutex_lock_interruptible(&u->readlock)) { 1992 err = sock_intr_errno(timeo); 1993 goto out; 1994 } 1995 1996 continue; 1997 unlock: 1998 unix_state_unlock(sk); 1999 break; 2000 } 2001 2002 skip = sk_peek_offset(sk, flags); 2003 while (skip >= unix_skb_len(skb)) { 2004 skip -= unix_skb_len(skb); 2005 last = skb; 2006 skb = skb_peek_next(skb, &sk->sk_receive_queue); 2007 if (!skb) 2008 goto again; 2009 } 2010 2011 unix_state_unlock(sk); 2012 2013 if (check_creds) { 2014 /* Never glue messages from different writers */ 2015 if ((UNIXCB(skb).pid != siocb->scm->pid) || 2016 !uid_eq(UNIXCB(skb).uid, siocb->scm->creds.uid) || 2017 !gid_eq(UNIXCB(skb).gid, siocb->scm->creds.gid)) 2018 break; 2019 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) { 2020 /* Copy credentials */ 2021 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); 2022 check_creds = 1; 2023 } 2024 2025 /* Copy address just once */ 2026 if (sunaddr) { 2027 unix_copy_addr(msg, skb->sk); 2028 sunaddr = NULL; 2029 } 2030 2031 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size); 2032 if (skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip, 2033 msg, chunk)) { 2034 if (copied == 0) 2035 copied = -EFAULT; 2036 break; 2037 } 2038 copied += chunk; 2039 size -= chunk; 2040 2041 /* Mark read part of skb as used */ 2042 if (!(flags & MSG_PEEK)) { 2043 UNIXCB(skb).consumed += chunk; 2044 2045 sk_peek_offset_bwd(sk, chunk); 2046 2047 if (UNIXCB(skb).fp) 2048 unix_detach_fds(siocb->scm, skb); 2049 2050 if (unix_skb_len(skb)) 2051 break; 2052 2053 skb_unlink(skb, &sk->sk_receive_queue); 2054 consume_skb(skb); 2055 2056 if (siocb->scm->fp) 2057 break; 2058 } else { 2059 /* It is questionable, see note in unix_dgram_recvmsg. 2060 */ 2061 if (UNIXCB(skb).fp) 2062 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 2063 2064 sk_peek_offset_fwd(sk, chunk); 2065 2066 break; 2067 } 2068 } while (size); 2069 2070 mutex_unlock(&u->readlock); 2071 scm_recv(sock, msg, siocb->scm, flags); 2072 out: 2073 return copied ? : err; 2074 } 2075 2076 static int unix_shutdown(struct socket *sock, int mode) 2077 { 2078 struct sock *sk = sock->sk; 2079 struct sock *other; 2080 2081 if (mode < SHUT_RD || mode > SHUT_RDWR) 2082 return -EINVAL; 2083 /* This maps: 2084 * SHUT_RD (0) -> RCV_SHUTDOWN (1) 2085 * SHUT_WR (1) -> SEND_SHUTDOWN (2) 2086 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3) 2087 */ 2088 ++mode; 2089 2090 unix_state_lock(sk); 2091 sk->sk_shutdown |= mode; 2092 other = unix_peer(sk); 2093 if (other) 2094 sock_hold(other); 2095 unix_state_unlock(sk); 2096 sk->sk_state_change(sk); 2097 2098 if (other && 2099 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) { 2100 2101 int peer_mode = 0; 2102 2103 if (mode&RCV_SHUTDOWN) 2104 peer_mode |= SEND_SHUTDOWN; 2105 if (mode&SEND_SHUTDOWN) 2106 peer_mode |= RCV_SHUTDOWN; 2107 unix_state_lock(other); 2108 other->sk_shutdown |= peer_mode; 2109 unix_state_unlock(other); 2110 other->sk_state_change(other); 2111 if (peer_mode == SHUTDOWN_MASK) 2112 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP); 2113 else if (peer_mode & RCV_SHUTDOWN) 2114 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN); 2115 } 2116 if (other) 2117 sock_put(other); 2118 2119 return 0; 2120 } 2121 2122 long unix_inq_len(struct sock *sk) 2123 { 2124 struct sk_buff *skb; 2125 long amount = 0; 2126 2127 if (sk->sk_state == TCP_LISTEN) 2128 return -EINVAL; 2129 2130 spin_lock(&sk->sk_receive_queue.lock); 2131 if (sk->sk_type == SOCK_STREAM || 2132 sk->sk_type == SOCK_SEQPACKET) { 2133 skb_queue_walk(&sk->sk_receive_queue, skb) 2134 amount += unix_skb_len(skb); 2135 } else { 2136 skb = skb_peek(&sk->sk_receive_queue); 2137 if (skb) 2138 amount = skb->len; 2139 } 2140 spin_unlock(&sk->sk_receive_queue.lock); 2141 2142 return amount; 2143 } 2144 EXPORT_SYMBOL_GPL(unix_inq_len); 2145 2146 long unix_outq_len(struct sock *sk) 2147 { 2148 return sk_wmem_alloc_get(sk); 2149 } 2150 EXPORT_SYMBOL_GPL(unix_outq_len); 2151 2152 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 2153 { 2154 struct sock *sk = sock->sk; 2155 long amount = 0; 2156 int err; 2157 2158 switch (cmd) { 2159 case SIOCOUTQ: 2160 amount = unix_outq_len(sk); 2161 err = put_user(amount, (int __user *)arg); 2162 break; 2163 case SIOCINQ: 2164 amount = unix_inq_len(sk); 2165 if (amount < 0) 2166 err = amount; 2167 else 2168 err = put_user(amount, (int __user *)arg); 2169 break; 2170 default: 2171 err = -ENOIOCTLCMD; 2172 break; 2173 } 2174 return err; 2175 } 2176 2177 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait) 2178 { 2179 struct sock *sk = sock->sk; 2180 unsigned int mask; 2181 2182 sock_poll_wait(file, sk_sleep(sk), wait); 2183 mask = 0; 2184 2185 /* exceptional events? */ 2186 if (sk->sk_err) 2187 mask |= POLLERR; 2188 if (sk->sk_shutdown == SHUTDOWN_MASK) 2189 mask |= POLLHUP; 2190 if (sk->sk_shutdown & RCV_SHUTDOWN) 2191 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2192 2193 /* readable? */ 2194 if (!skb_queue_empty(&sk->sk_receive_queue)) 2195 mask |= POLLIN | POLLRDNORM; 2196 2197 /* Connection-based need to check for termination and startup */ 2198 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && 2199 sk->sk_state == TCP_CLOSE) 2200 mask |= POLLHUP; 2201 2202 /* 2203 * we set writable also when the other side has shut down the 2204 * connection. This prevents stuck sockets. 2205 */ 2206 if (unix_writable(sk)) 2207 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2208 2209 return mask; 2210 } 2211 2212 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, 2213 poll_table *wait) 2214 { 2215 struct sock *sk = sock->sk, *other; 2216 unsigned int mask, writable; 2217 2218 sock_poll_wait(file, sk_sleep(sk), wait); 2219 mask = 0; 2220 2221 /* exceptional events? */ 2222 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) 2223 mask |= POLLERR | 2224 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0); 2225 2226 if (sk->sk_shutdown & RCV_SHUTDOWN) 2227 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2228 if (sk->sk_shutdown == SHUTDOWN_MASK) 2229 mask |= POLLHUP; 2230 2231 /* readable? */ 2232 if (!skb_queue_empty(&sk->sk_receive_queue)) 2233 mask |= POLLIN | POLLRDNORM; 2234 2235 /* Connection-based need to check for termination and startup */ 2236 if (sk->sk_type == SOCK_SEQPACKET) { 2237 if (sk->sk_state == TCP_CLOSE) 2238 mask |= POLLHUP; 2239 /* connection hasn't started yet? */ 2240 if (sk->sk_state == TCP_SYN_SENT) 2241 return mask; 2242 } 2243 2244 /* No write status requested, avoid expensive OUT tests. */ 2245 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT))) 2246 return mask; 2247 2248 writable = unix_writable(sk); 2249 other = unix_peer_get(sk); 2250 if (other) { 2251 if (unix_peer(other) != sk) { 2252 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait); 2253 if (unix_recvq_full(other)) 2254 writable = 0; 2255 } 2256 sock_put(other); 2257 } 2258 2259 if (writable) 2260 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2261 else 2262 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 2263 2264 return mask; 2265 } 2266 2267 #ifdef CONFIG_PROC_FS 2268 2269 #define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1) 2270 2271 #define get_bucket(x) ((x) >> BUCKET_SPACE) 2272 #define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1)) 2273 #define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o)) 2274 2275 static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos) 2276 { 2277 unsigned long offset = get_offset(*pos); 2278 unsigned long bucket = get_bucket(*pos); 2279 struct sock *sk; 2280 unsigned long count = 0; 2281 2282 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) { 2283 if (sock_net(sk) != seq_file_net(seq)) 2284 continue; 2285 if (++count == offset) 2286 break; 2287 } 2288 2289 return sk; 2290 } 2291 2292 static struct sock *unix_next_socket(struct seq_file *seq, 2293 struct sock *sk, 2294 loff_t *pos) 2295 { 2296 unsigned long bucket; 2297 2298 while (sk > (struct sock *)SEQ_START_TOKEN) { 2299 sk = sk_next(sk); 2300 if (!sk) 2301 goto next_bucket; 2302 if (sock_net(sk) == seq_file_net(seq)) 2303 return sk; 2304 } 2305 2306 do { 2307 sk = unix_from_bucket(seq, pos); 2308 if (sk) 2309 return sk; 2310 2311 next_bucket: 2312 bucket = get_bucket(*pos) + 1; 2313 *pos = set_bucket_offset(bucket, 1); 2314 } while (bucket < ARRAY_SIZE(unix_socket_table)); 2315 2316 return NULL; 2317 } 2318 2319 static void *unix_seq_start(struct seq_file *seq, loff_t *pos) 2320 __acquires(unix_table_lock) 2321 { 2322 spin_lock(&unix_table_lock); 2323 2324 if (!*pos) 2325 return SEQ_START_TOKEN; 2326 2327 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table)) 2328 return NULL; 2329 2330 return unix_next_socket(seq, NULL, pos); 2331 } 2332 2333 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2334 { 2335 ++*pos; 2336 return unix_next_socket(seq, v, pos); 2337 } 2338 2339 static void unix_seq_stop(struct seq_file *seq, void *v) 2340 __releases(unix_table_lock) 2341 { 2342 spin_unlock(&unix_table_lock); 2343 } 2344 2345 static int unix_seq_show(struct seq_file *seq, void *v) 2346 { 2347 2348 if (v == SEQ_START_TOKEN) 2349 seq_puts(seq, "Num RefCount Protocol Flags Type St " 2350 "Inode Path\n"); 2351 else { 2352 struct sock *s = v; 2353 struct unix_sock *u = unix_sk(s); 2354 unix_state_lock(s); 2355 2356 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu", 2357 s, 2358 atomic_read(&s->sk_refcnt), 2359 0, 2360 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0, 2361 s->sk_type, 2362 s->sk_socket ? 2363 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) : 2364 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING), 2365 sock_i_ino(s)); 2366 2367 if (u->addr) { 2368 int i, len; 2369 seq_putc(seq, ' '); 2370 2371 i = 0; 2372 len = u->addr->len - sizeof(short); 2373 if (!UNIX_ABSTRACT(s)) 2374 len--; 2375 else { 2376 seq_putc(seq, '@'); 2377 i++; 2378 } 2379 for ( ; i < len; i++) 2380 seq_putc(seq, u->addr->name->sun_path[i]); 2381 } 2382 unix_state_unlock(s); 2383 seq_putc(seq, '\n'); 2384 } 2385 2386 return 0; 2387 } 2388 2389 static const struct seq_operations unix_seq_ops = { 2390 .start = unix_seq_start, 2391 .next = unix_seq_next, 2392 .stop = unix_seq_stop, 2393 .show = unix_seq_show, 2394 }; 2395 2396 static int unix_seq_open(struct inode *inode, struct file *file) 2397 { 2398 return seq_open_net(inode, file, &unix_seq_ops, 2399 sizeof(struct seq_net_private)); 2400 } 2401 2402 static const struct file_operations unix_seq_fops = { 2403 .owner = THIS_MODULE, 2404 .open = unix_seq_open, 2405 .read = seq_read, 2406 .llseek = seq_lseek, 2407 .release = seq_release_net, 2408 }; 2409 2410 #endif 2411 2412 static const struct net_proto_family unix_family_ops = { 2413 .family = PF_UNIX, 2414 .create = unix_create, 2415 .owner = THIS_MODULE, 2416 }; 2417 2418 2419 static int __net_init unix_net_init(struct net *net) 2420 { 2421 int error = -ENOMEM; 2422 2423 net->unx.sysctl_max_dgram_qlen = 10; 2424 if (unix_sysctl_register(net)) 2425 goto out; 2426 2427 #ifdef CONFIG_PROC_FS 2428 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) { 2429 unix_sysctl_unregister(net); 2430 goto out; 2431 } 2432 #endif 2433 error = 0; 2434 out: 2435 return error; 2436 } 2437 2438 static void __net_exit unix_net_exit(struct net *net) 2439 { 2440 unix_sysctl_unregister(net); 2441 remove_proc_entry("unix", net->proc_net); 2442 } 2443 2444 static struct pernet_operations unix_net_ops = { 2445 .init = unix_net_init, 2446 .exit = unix_net_exit, 2447 }; 2448 2449 static int __init af_unix_init(void) 2450 { 2451 int rc = -1; 2452 2453 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb)); 2454 2455 rc = proto_register(&unix_proto, 1); 2456 if (rc != 0) { 2457 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__); 2458 goto out; 2459 } 2460 2461 sock_register(&unix_family_ops); 2462 register_pernet_subsys(&unix_net_ops); 2463 out: 2464 return rc; 2465 } 2466 2467 static void __exit af_unix_exit(void) 2468 { 2469 sock_unregister(PF_UNIX); 2470 proto_unregister(&unix_proto); 2471 unregister_pernet_subsys(&unix_net_ops); 2472 } 2473 2474 /* Earlier than device_initcall() so that other drivers invoking 2475 request_module() don't end up in a loop when modprobe tries 2476 to use a UNIX socket. But later than subsys_initcall() because 2477 we depend on stuff initialised there */ 2478 fs_initcall(af_unix_init); 2479 module_exit(af_unix_exit); 2480 2481 MODULE_LICENSE("GPL"); 2482 MODULE_ALIAS_NETPROTO(PF_UNIX); 2483