1 /* 2 * NETLINK Kernel-user communication protocol. 3 * 4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk> 5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 6 * Patrick McHardy <kaber@trash.net> 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License 10 * as published by the Free Software Foundation; either version 11 * 2 of the License, or (at your option) any later version. 12 * 13 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith 14 * added netlink_proto_exit 15 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br> 16 * use nlk_sk, as sk->protinfo is on a diet 8) 17 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org> 18 * - inc module use count of module that owns 19 * the kernel socket in case userspace opens 20 * socket of same protocol 21 * - remove all module support, since netlink is 22 * mandatory if CONFIG_NET=y these days 23 */ 24 25 #include <linux/module.h> 26 27 #include <linux/capability.h> 28 #include <linux/kernel.h> 29 #include <linux/init.h> 30 #include <linux/signal.h> 31 #include <linux/sched.h> 32 #include <linux/errno.h> 33 #include <linux/string.h> 34 #include <linux/stat.h> 35 #include <linux/socket.h> 36 #include <linux/un.h> 37 #include <linux/fcntl.h> 38 #include <linux/termios.h> 39 #include <linux/sockios.h> 40 #include <linux/net.h> 41 #include <linux/fs.h> 42 #include <linux/slab.h> 43 #include <linux/uaccess.h> 44 #include <linux/skbuff.h> 45 #include <linux/netdevice.h> 46 #include <linux/rtnetlink.h> 47 #include <linux/proc_fs.h> 48 #include <linux/seq_file.h> 49 #include <linux/notifier.h> 50 #include <linux/security.h> 51 #include <linux/jhash.h> 52 #include <linux/jiffies.h> 53 #include <linux/random.h> 54 #include <linux/bitops.h> 55 #include <linux/mm.h> 56 #include <linux/types.h> 57 #include <linux/audit.h> 58 #include <linux/mutex.h> 59 #include <linux/vmalloc.h> 60 #include <linux/if_arp.h> 61 #include <linux/rhashtable.h> 62 #include <asm/cacheflush.h> 63 #include <linux/hash.h> 64 #include <linux/genetlink.h> 65 #include <linux/net_namespace.h> 66 #include <linux/nospec.h> 67 68 #include <net/net_namespace.h> 69 #include <net/netns/generic.h> 70 #include <net/sock.h> 71 #include <net/scm.h> 72 #include <net/netlink.h> 73 74 #include "af_netlink.h" 75 76 struct listeners { 77 struct rcu_head rcu; 78 unsigned long masks[0]; 79 }; 80 81 /* state bits */ 82 #define NETLINK_S_CONGESTED 0x0 83 84 static inline int netlink_is_kernel(struct sock *sk) 85 { 86 return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET; 87 } 88 89 struct netlink_table *nl_table __read_mostly; 90 EXPORT_SYMBOL_GPL(nl_table); 91 92 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); 93 94 static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS]; 95 96 static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = { 97 "nlk_cb_mutex-ROUTE", 98 "nlk_cb_mutex-1", 99 "nlk_cb_mutex-USERSOCK", 100 "nlk_cb_mutex-FIREWALL", 101 "nlk_cb_mutex-SOCK_DIAG", 102 "nlk_cb_mutex-NFLOG", 103 "nlk_cb_mutex-XFRM", 104 "nlk_cb_mutex-SELINUX", 105 "nlk_cb_mutex-ISCSI", 106 "nlk_cb_mutex-AUDIT", 107 "nlk_cb_mutex-FIB_LOOKUP", 108 "nlk_cb_mutex-CONNECTOR", 109 "nlk_cb_mutex-NETFILTER", 110 "nlk_cb_mutex-IP6_FW", 111 "nlk_cb_mutex-DNRTMSG", 112 "nlk_cb_mutex-KOBJECT_UEVENT", 113 "nlk_cb_mutex-GENERIC", 114 "nlk_cb_mutex-17", 115 "nlk_cb_mutex-SCSITRANSPORT", 116 "nlk_cb_mutex-ECRYPTFS", 117 "nlk_cb_mutex-RDMA", 118 "nlk_cb_mutex-CRYPTO", 119 "nlk_cb_mutex-SMC", 120 "nlk_cb_mutex-23", 121 "nlk_cb_mutex-24", 122 "nlk_cb_mutex-25", 123 "nlk_cb_mutex-26", 124 "nlk_cb_mutex-27", 125 "nlk_cb_mutex-28", 126 "nlk_cb_mutex-29", 127 "nlk_cb_mutex-30", 128 "nlk_cb_mutex-31", 129 "nlk_cb_mutex-MAX_LINKS" 130 }; 131 132 static int netlink_dump(struct sock *sk); 133 134 /* nl_table locking explained: 135 * Lookup and traversal are protected with an RCU read-side lock. Insertion 136 * and removal are protected with per bucket lock while using RCU list 137 * modification primitives and may run in parallel to RCU protected lookups. 138 * Destruction of the Netlink socket may only occur *after* nl_table_lock has 139 * been acquired * either during or after the socket has been removed from 140 * the list and after an RCU grace period. 141 */ 142 DEFINE_RWLOCK(nl_table_lock); 143 EXPORT_SYMBOL_GPL(nl_table_lock); 144 static atomic_t nl_table_users = ATOMIC_INIT(0); 145 146 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock)); 147 148 static BLOCKING_NOTIFIER_HEAD(netlink_chain); 149 150 151 static const struct rhashtable_params netlink_rhashtable_params; 152 153 static inline u32 netlink_group_mask(u32 group) 154 { 155 return group ? 1 << (group - 1) : 0; 156 } 157 158 static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb, 159 gfp_t gfp_mask) 160 { 161 unsigned int len = skb_end_offset(skb); 162 struct sk_buff *new; 163 164 new = alloc_skb(len, gfp_mask); 165 if (new == NULL) 166 return NULL; 167 168 NETLINK_CB(new).portid = NETLINK_CB(skb).portid; 169 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group; 170 NETLINK_CB(new).creds = NETLINK_CB(skb).creds; 171 172 skb_put_data(new, skb->data, len); 173 return new; 174 } 175 176 static unsigned int netlink_tap_net_id; 177 178 struct netlink_tap_net { 179 struct list_head netlink_tap_all; 180 struct mutex netlink_tap_lock; 181 }; 182 183 int netlink_add_tap(struct netlink_tap *nt) 184 { 185 struct net *net = dev_net(nt->dev); 186 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 187 188 if (unlikely(nt->dev->type != ARPHRD_NETLINK)) 189 return -EINVAL; 190 191 mutex_lock(&nn->netlink_tap_lock); 192 list_add_rcu(&nt->list, &nn->netlink_tap_all); 193 mutex_unlock(&nn->netlink_tap_lock); 194 195 __module_get(nt->module); 196 197 return 0; 198 } 199 EXPORT_SYMBOL_GPL(netlink_add_tap); 200 201 static int __netlink_remove_tap(struct netlink_tap *nt) 202 { 203 struct net *net = dev_net(nt->dev); 204 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 205 bool found = false; 206 struct netlink_tap *tmp; 207 208 mutex_lock(&nn->netlink_tap_lock); 209 210 list_for_each_entry(tmp, &nn->netlink_tap_all, list) { 211 if (nt == tmp) { 212 list_del_rcu(&nt->list); 213 found = true; 214 goto out; 215 } 216 } 217 218 pr_warn("__netlink_remove_tap: %p not found\n", nt); 219 out: 220 mutex_unlock(&nn->netlink_tap_lock); 221 222 if (found) 223 module_put(nt->module); 224 225 return found ? 0 : -ENODEV; 226 } 227 228 int netlink_remove_tap(struct netlink_tap *nt) 229 { 230 int ret; 231 232 ret = __netlink_remove_tap(nt); 233 synchronize_net(); 234 235 return ret; 236 } 237 EXPORT_SYMBOL_GPL(netlink_remove_tap); 238 239 static __net_init int netlink_tap_init_net(struct net *net) 240 { 241 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 242 243 INIT_LIST_HEAD(&nn->netlink_tap_all); 244 mutex_init(&nn->netlink_tap_lock); 245 return 0; 246 } 247 248 static void __net_exit netlink_tap_exit_net(struct net *net) 249 { 250 } 251 252 static struct pernet_operations netlink_tap_net_ops = { 253 .init = netlink_tap_init_net, 254 .exit = netlink_tap_exit_net, 255 .id = &netlink_tap_net_id, 256 .size = sizeof(struct netlink_tap_net), 257 }; 258 259 static bool netlink_filter_tap(const struct sk_buff *skb) 260 { 261 struct sock *sk = skb->sk; 262 263 /* We take the more conservative approach and 264 * whitelist socket protocols that may pass. 265 */ 266 switch (sk->sk_protocol) { 267 case NETLINK_ROUTE: 268 case NETLINK_USERSOCK: 269 case NETLINK_SOCK_DIAG: 270 case NETLINK_NFLOG: 271 case NETLINK_XFRM: 272 case NETLINK_FIB_LOOKUP: 273 case NETLINK_NETFILTER: 274 case NETLINK_GENERIC: 275 return true; 276 } 277 278 return false; 279 } 280 281 static int __netlink_deliver_tap_skb(struct sk_buff *skb, 282 struct net_device *dev) 283 { 284 struct sk_buff *nskb; 285 struct sock *sk = skb->sk; 286 int ret = -ENOMEM; 287 288 if (!net_eq(dev_net(dev), sock_net(sk))) 289 return 0; 290 291 dev_hold(dev); 292 293 if (is_vmalloc_addr(skb->head)) 294 nskb = netlink_to_full_skb(skb, GFP_ATOMIC); 295 else 296 nskb = skb_clone(skb, GFP_ATOMIC); 297 if (nskb) { 298 nskb->dev = dev; 299 nskb->protocol = htons((u16) sk->sk_protocol); 300 nskb->pkt_type = netlink_is_kernel(sk) ? 301 PACKET_KERNEL : PACKET_USER; 302 skb_reset_network_header(nskb); 303 ret = dev_queue_xmit(nskb); 304 if (unlikely(ret > 0)) 305 ret = net_xmit_errno(ret); 306 } 307 308 dev_put(dev); 309 return ret; 310 } 311 312 static void __netlink_deliver_tap(struct sk_buff *skb, struct netlink_tap_net *nn) 313 { 314 int ret; 315 struct netlink_tap *tmp; 316 317 if (!netlink_filter_tap(skb)) 318 return; 319 320 list_for_each_entry_rcu(tmp, &nn->netlink_tap_all, list) { 321 ret = __netlink_deliver_tap_skb(skb, tmp->dev); 322 if (unlikely(ret)) 323 break; 324 } 325 } 326 327 static void netlink_deliver_tap(struct net *net, struct sk_buff *skb) 328 { 329 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 330 331 rcu_read_lock(); 332 333 if (unlikely(!list_empty(&nn->netlink_tap_all))) 334 __netlink_deliver_tap(skb, nn); 335 336 rcu_read_unlock(); 337 } 338 339 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src, 340 struct sk_buff *skb) 341 { 342 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src))) 343 netlink_deliver_tap(sock_net(dst), skb); 344 } 345 346 static void netlink_overrun(struct sock *sk) 347 { 348 struct netlink_sock *nlk = nlk_sk(sk); 349 350 if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) { 351 if (!test_and_set_bit(NETLINK_S_CONGESTED, 352 &nlk_sk(sk)->state)) { 353 sk->sk_err = ENOBUFS; 354 sk->sk_error_report(sk); 355 } 356 } 357 atomic_inc(&sk->sk_drops); 358 } 359 360 static void netlink_rcv_wake(struct sock *sk) 361 { 362 struct netlink_sock *nlk = nlk_sk(sk); 363 364 if (skb_queue_empty(&sk->sk_receive_queue)) 365 clear_bit(NETLINK_S_CONGESTED, &nlk->state); 366 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state)) 367 wake_up_interruptible(&nlk->wait); 368 } 369 370 static void netlink_skb_destructor(struct sk_buff *skb) 371 { 372 if (is_vmalloc_addr(skb->head)) { 373 if (!skb->cloned || 374 !atomic_dec_return(&(skb_shinfo(skb)->dataref))) 375 vfree(skb->head); 376 377 skb->head = NULL; 378 } 379 if (skb->sk != NULL) 380 sock_rfree(skb); 381 } 382 383 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk) 384 { 385 WARN_ON(skb->sk != NULL); 386 skb->sk = sk; 387 skb->destructor = netlink_skb_destructor; 388 atomic_add(skb->truesize, &sk->sk_rmem_alloc); 389 sk_mem_charge(sk, skb->truesize); 390 } 391 392 static void netlink_sock_destruct(struct sock *sk) 393 { 394 struct netlink_sock *nlk = nlk_sk(sk); 395 396 if (nlk->cb_running) { 397 if (nlk->cb.done) 398 nlk->cb.done(&nlk->cb); 399 module_put(nlk->cb.module); 400 kfree_skb(nlk->cb.skb); 401 } 402 403 skb_queue_purge(&sk->sk_receive_queue); 404 405 if (!sock_flag(sk, SOCK_DEAD)) { 406 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk); 407 return; 408 } 409 410 WARN_ON(atomic_read(&sk->sk_rmem_alloc)); 411 WARN_ON(refcount_read(&sk->sk_wmem_alloc)); 412 WARN_ON(nlk_sk(sk)->groups); 413 } 414 415 static void netlink_sock_destruct_work(struct work_struct *work) 416 { 417 struct netlink_sock *nlk = container_of(work, struct netlink_sock, 418 work); 419 420 sk_free(&nlk->sk); 421 } 422 423 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on 424 * SMP. Look, when several writers sleep and reader wakes them up, all but one 425 * immediately hit write lock and grab all the cpus. Exclusive sleep solves 426 * this, _but_ remember, it adds useless work on UP machines. 427 */ 428 429 void netlink_table_grab(void) 430 __acquires(nl_table_lock) 431 { 432 might_sleep(); 433 434 write_lock_irq(&nl_table_lock); 435 436 if (atomic_read(&nl_table_users)) { 437 DECLARE_WAITQUEUE(wait, current); 438 439 add_wait_queue_exclusive(&nl_table_wait, &wait); 440 for (;;) { 441 set_current_state(TASK_UNINTERRUPTIBLE); 442 if (atomic_read(&nl_table_users) == 0) 443 break; 444 write_unlock_irq(&nl_table_lock); 445 schedule(); 446 write_lock_irq(&nl_table_lock); 447 } 448 449 __set_current_state(TASK_RUNNING); 450 remove_wait_queue(&nl_table_wait, &wait); 451 } 452 } 453 454 void netlink_table_ungrab(void) 455 __releases(nl_table_lock) 456 { 457 write_unlock_irq(&nl_table_lock); 458 wake_up(&nl_table_wait); 459 } 460 461 static inline void 462 netlink_lock_table(void) 463 { 464 /* read_lock() synchronizes us to netlink_table_grab */ 465 466 read_lock(&nl_table_lock); 467 atomic_inc(&nl_table_users); 468 read_unlock(&nl_table_lock); 469 } 470 471 static inline void 472 netlink_unlock_table(void) 473 { 474 if (atomic_dec_and_test(&nl_table_users)) 475 wake_up(&nl_table_wait); 476 } 477 478 struct netlink_compare_arg 479 { 480 possible_net_t pnet; 481 u32 portid; 482 }; 483 484 /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */ 485 #define netlink_compare_arg_len \ 486 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32)) 487 488 static inline int netlink_compare(struct rhashtable_compare_arg *arg, 489 const void *ptr) 490 { 491 const struct netlink_compare_arg *x = arg->key; 492 const struct netlink_sock *nlk = ptr; 493 494 return nlk->portid != x->portid || 495 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet)); 496 } 497 498 static void netlink_compare_arg_init(struct netlink_compare_arg *arg, 499 struct net *net, u32 portid) 500 { 501 memset(arg, 0, sizeof(*arg)); 502 write_pnet(&arg->pnet, net); 503 arg->portid = portid; 504 } 505 506 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid, 507 struct net *net) 508 { 509 struct netlink_compare_arg arg; 510 511 netlink_compare_arg_init(&arg, net, portid); 512 return rhashtable_lookup_fast(&table->hash, &arg, 513 netlink_rhashtable_params); 514 } 515 516 static int __netlink_insert(struct netlink_table *table, struct sock *sk) 517 { 518 struct netlink_compare_arg arg; 519 520 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid); 521 return rhashtable_lookup_insert_key(&table->hash, &arg, 522 &nlk_sk(sk)->node, 523 netlink_rhashtable_params); 524 } 525 526 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid) 527 { 528 struct netlink_table *table = &nl_table[protocol]; 529 struct sock *sk; 530 531 rcu_read_lock(); 532 sk = __netlink_lookup(table, portid, net); 533 if (sk) 534 sock_hold(sk); 535 rcu_read_unlock(); 536 537 return sk; 538 } 539 540 static const struct proto_ops netlink_ops; 541 542 static void 543 netlink_update_listeners(struct sock *sk) 544 { 545 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 546 unsigned long mask; 547 unsigned int i; 548 struct listeners *listeners; 549 550 listeners = nl_deref_protected(tbl->listeners); 551 if (!listeners) 552 return; 553 554 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) { 555 mask = 0; 556 sk_for_each_bound(sk, &tbl->mc_list) { 557 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups)) 558 mask |= nlk_sk(sk)->groups[i]; 559 } 560 listeners->masks[i] = mask; 561 } 562 /* this function is only called with the netlink table "grabbed", which 563 * makes sure updates are visible before bind or setsockopt return. */ 564 } 565 566 static int netlink_insert(struct sock *sk, u32 portid) 567 { 568 struct netlink_table *table = &nl_table[sk->sk_protocol]; 569 int err; 570 571 lock_sock(sk); 572 573 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY; 574 if (nlk_sk(sk)->bound) 575 goto err; 576 577 nlk_sk(sk)->portid = portid; 578 sock_hold(sk); 579 580 err = __netlink_insert(table, sk); 581 if (err) { 582 /* In case the hashtable backend returns with -EBUSY 583 * from here, it must not escape to the caller. 584 */ 585 if (unlikely(err == -EBUSY)) 586 err = -EOVERFLOW; 587 if (err == -EEXIST) 588 err = -EADDRINUSE; 589 sock_put(sk); 590 goto err; 591 } 592 593 /* We need to ensure that the socket is hashed and visible. */ 594 smp_wmb(); 595 nlk_sk(sk)->bound = portid; 596 597 err: 598 release_sock(sk); 599 return err; 600 } 601 602 static void netlink_remove(struct sock *sk) 603 { 604 struct netlink_table *table; 605 606 table = &nl_table[sk->sk_protocol]; 607 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node, 608 netlink_rhashtable_params)) { 609 WARN_ON(refcount_read(&sk->sk_refcnt) == 1); 610 __sock_put(sk); 611 } 612 613 netlink_table_grab(); 614 if (nlk_sk(sk)->subscriptions) { 615 __sk_del_bind_node(sk); 616 netlink_update_listeners(sk); 617 } 618 if (sk->sk_protocol == NETLINK_GENERIC) 619 atomic_inc(&genl_sk_destructing_cnt); 620 netlink_table_ungrab(); 621 } 622 623 static struct proto netlink_proto = { 624 .name = "NETLINK", 625 .owner = THIS_MODULE, 626 .obj_size = sizeof(struct netlink_sock), 627 }; 628 629 static int __netlink_create(struct net *net, struct socket *sock, 630 struct mutex *cb_mutex, int protocol, 631 int kern) 632 { 633 struct sock *sk; 634 struct netlink_sock *nlk; 635 636 sock->ops = &netlink_ops; 637 638 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern); 639 if (!sk) 640 return -ENOMEM; 641 642 sock_init_data(sock, sk); 643 644 nlk = nlk_sk(sk); 645 if (cb_mutex) { 646 nlk->cb_mutex = cb_mutex; 647 } else { 648 nlk->cb_mutex = &nlk->cb_def_mutex; 649 mutex_init(nlk->cb_mutex); 650 lockdep_set_class_and_name(nlk->cb_mutex, 651 nlk_cb_mutex_keys + protocol, 652 nlk_cb_mutex_key_strings[protocol]); 653 } 654 init_waitqueue_head(&nlk->wait); 655 656 sk->sk_destruct = netlink_sock_destruct; 657 sk->sk_protocol = protocol; 658 return 0; 659 } 660 661 static int netlink_create(struct net *net, struct socket *sock, int protocol, 662 int kern) 663 { 664 struct module *module = NULL; 665 struct mutex *cb_mutex; 666 struct netlink_sock *nlk; 667 int (*bind)(struct net *net, int group); 668 void (*unbind)(struct net *net, int group); 669 int err = 0; 670 671 sock->state = SS_UNCONNECTED; 672 673 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) 674 return -ESOCKTNOSUPPORT; 675 676 if (protocol < 0 || protocol >= MAX_LINKS) 677 return -EPROTONOSUPPORT; 678 protocol = array_index_nospec(protocol, MAX_LINKS); 679 680 netlink_lock_table(); 681 #ifdef CONFIG_MODULES 682 if (!nl_table[protocol].registered) { 683 netlink_unlock_table(); 684 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); 685 netlink_lock_table(); 686 } 687 #endif 688 if (nl_table[protocol].registered && 689 try_module_get(nl_table[protocol].module)) 690 module = nl_table[protocol].module; 691 else 692 err = -EPROTONOSUPPORT; 693 cb_mutex = nl_table[protocol].cb_mutex; 694 bind = nl_table[protocol].bind; 695 unbind = nl_table[protocol].unbind; 696 netlink_unlock_table(); 697 698 if (err < 0) 699 goto out; 700 701 err = __netlink_create(net, sock, cb_mutex, protocol, kern); 702 if (err < 0) 703 goto out_module; 704 705 local_bh_disable(); 706 sock_prot_inuse_add(net, &netlink_proto, 1); 707 local_bh_enable(); 708 709 nlk = nlk_sk(sock->sk); 710 nlk->module = module; 711 nlk->netlink_bind = bind; 712 nlk->netlink_unbind = unbind; 713 out: 714 return err; 715 716 out_module: 717 module_put(module); 718 goto out; 719 } 720 721 static void deferred_put_nlk_sk(struct rcu_head *head) 722 { 723 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu); 724 struct sock *sk = &nlk->sk; 725 726 kfree(nlk->groups); 727 nlk->groups = NULL; 728 729 if (!refcount_dec_and_test(&sk->sk_refcnt)) 730 return; 731 732 if (nlk->cb_running && nlk->cb.done) { 733 INIT_WORK(&nlk->work, netlink_sock_destruct_work); 734 schedule_work(&nlk->work); 735 return; 736 } 737 738 sk_free(sk); 739 } 740 741 static int netlink_release(struct socket *sock) 742 { 743 struct sock *sk = sock->sk; 744 struct netlink_sock *nlk; 745 746 if (!sk) 747 return 0; 748 749 netlink_remove(sk); 750 sock_orphan(sk); 751 nlk = nlk_sk(sk); 752 753 /* 754 * OK. Socket is unlinked, any packets that arrive now 755 * will be purged. 756 */ 757 758 /* must not acquire netlink_table_lock in any way again before unbind 759 * and notifying genetlink is done as otherwise it might deadlock 760 */ 761 if (nlk->netlink_unbind) { 762 int i; 763 764 for (i = 0; i < nlk->ngroups; i++) 765 if (test_bit(i, nlk->groups)) 766 nlk->netlink_unbind(sock_net(sk), i + 1); 767 } 768 if (sk->sk_protocol == NETLINK_GENERIC && 769 atomic_dec_return(&genl_sk_destructing_cnt) == 0) 770 wake_up(&genl_sk_destructing_waitq); 771 772 sock->sk = NULL; 773 wake_up_interruptible_all(&nlk->wait); 774 775 skb_queue_purge(&sk->sk_write_queue); 776 777 if (nlk->portid && nlk->bound) { 778 struct netlink_notify n = { 779 .net = sock_net(sk), 780 .protocol = sk->sk_protocol, 781 .portid = nlk->portid, 782 }; 783 blocking_notifier_call_chain(&netlink_chain, 784 NETLINK_URELEASE, &n); 785 } 786 787 module_put(nlk->module); 788 789 if (netlink_is_kernel(sk)) { 790 netlink_table_grab(); 791 BUG_ON(nl_table[sk->sk_protocol].registered == 0); 792 if (--nl_table[sk->sk_protocol].registered == 0) { 793 struct listeners *old; 794 795 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners); 796 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL); 797 kfree_rcu(old, rcu); 798 nl_table[sk->sk_protocol].module = NULL; 799 nl_table[sk->sk_protocol].bind = NULL; 800 nl_table[sk->sk_protocol].unbind = NULL; 801 nl_table[sk->sk_protocol].flags = 0; 802 nl_table[sk->sk_protocol].registered = 0; 803 } 804 netlink_table_ungrab(); 805 } 806 807 local_bh_disable(); 808 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1); 809 local_bh_enable(); 810 call_rcu(&nlk->rcu, deferred_put_nlk_sk); 811 return 0; 812 } 813 814 static int netlink_autobind(struct socket *sock) 815 { 816 struct sock *sk = sock->sk; 817 struct net *net = sock_net(sk); 818 struct netlink_table *table = &nl_table[sk->sk_protocol]; 819 s32 portid = task_tgid_vnr(current); 820 int err; 821 s32 rover = -4096; 822 bool ok; 823 824 retry: 825 cond_resched(); 826 rcu_read_lock(); 827 ok = !__netlink_lookup(table, portid, net); 828 rcu_read_unlock(); 829 if (!ok) { 830 /* Bind collision, search negative portid values. */ 831 if (rover == -4096) 832 /* rover will be in range [S32_MIN, -4097] */ 833 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN); 834 else if (rover >= -4096) 835 rover = -4097; 836 portid = rover--; 837 goto retry; 838 } 839 840 err = netlink_insert(sk, portid); 841 if (err == -EADDRINUSE) 842 goto retry; 843 844 /* If 2 threads race to autobind, that is fine. */ 845 if (err == -EBUSY) 846 err = 0; 847 848 return err; 849 } 850 851 /** 852 * __netlink_ns_capable - General netlink message capability test 853 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace. 854 * @user_ns: The user namespace of the capability to use 855 * @cap: The capability to use 856 * 857 * Test to see if the opener of the socket we received the message 858 * from had when the netlink socket was created and the sender of the 859 * message has has the capability @cap in the user namespace @user_ns. 860 */ 861 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp, 862 struct user_namespace *user_ns, int cap) 863 { 864 return ((nsp->flags & NETLINK_SKB_DST) || 865 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) && 866 ns_capable(user_ns, cap); 867 } 868 EXPORT_SYMBOL(__netlink_ns_capable); 869 870 /** 871 * netlink_ns_capable - General netlink message capability test 872 * @skb: socket buffer holding a netlink command from userspace 873 * @user_ns: The user namespace of the capability to use 874 * @cap: The capability to use 875 * 876 * Test to see if the opener of the socket we received the message 877 * from had when the netlink socket was created and the sender of the 878 * message has has the capability @cap in the user namespace @user_ns. 879 */ 880 bool netlink_ns_capable(const struct sk_buff *skb, 881 struct user_namespace *user_ns, int cap) 882 { 883 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap); 884 } 885 EXPORT_SYMBOL(netlink_ns_capable); 886 887 /** 888 * netlink_capable - Netlink global message capability test 889 * @skb: socket buffer holding a netlink command from userspace 890 * @cap: The capability to use 891 * 892 * Test to see if the opener of the socket we received the message 893 * from had when the netlink socket was created and the sender of the 894 * message has has the capability @cap in all user namespaces. 895 */ 896 bool netlink_capable(const struct sk_buff *skb, int cap) 897 { 898 return netlink_ns_capable(skb, &init_user_ns, cap); 899 } 900 EXPORT_SYMBOL(netlink_capable); 901 902 /** 903 * netlink_net_capable - Netlink network namespace message capability test 904 * @skb: socket buffer holding a netlink command from userspace 905 * @cap: The capability to use 906 * 907 * Test to see if the opener of the socket we received the message 908 * from had when the netlink socket was created and the sender of the 909 * message has has the capability @cap over the network namespace of 910 * the socket we received the message from. 911 */ 912 bool netlink_net_capable(const struct sk_buff *skb, int cap) 913 { 914 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap); 915 } 916 EXPORT_SYMBOL(netlink_net_capable); 917 918 static inline int netlink_allowed(const struct socket *sock, unsigned int flag) 919 { 920 return (nl_table[sock->sk->sk_protocol].flags & flag) || 921 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN); 922 } 923 924 static void 925 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) 926 { 927 struct netlink_sock *nlk = nlk_sk(sk); 928 929 if (nlk->subscriptions && !subscriptions) 930 __sk_del_bind_node(sk); 931 else if (!nlk->subscriptions && subscriptions) 932 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); 933 nlk->subscriptions = subscriptions; 934 } 935 936 static int netlink_realloc_groups(struct sock *sk) 937 { 938 struct netlink_sock *nlk = nlk_sk(sk); 939 unsigned int groups; 940 unsigned long *new_groups; 941 int err = 0; 942 943 netlink_table_grab(); 944 945 groups = nl_table[sk->sk_protocol].groups; 946 if (!nl_table[sk->sk_protocol].registered) { 947 err = -ENOENT; 948 goto out_unlock; 949 } 950 951 if (nlk->ngroups >= groups) 952 goto out_unlock; 953 954 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC); 955 if (new_groups == NULL) { 956 err = -ENOMEM; 957 goto out_unlock; 958 } 959 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0, 960 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups)); 961 962 nlk->groups = new_groups; 963 nlk->ngroups = groups; 964 out_unlock: 965 netlink_table_ungrab(); 966 return err; 967 } 968 969 static void netlink_undo_bind(int group, long unsigned int groups, 970 struct sock *sk) 971 { 972 struct netlink_sock *nlk = nlk_sk(sk); 973 int undo; 974 975 if (!nlk->netlink_unbind) 976 return; 977 978 for (undo = 0; undo < group; undo++) 979 if (test_bit(undo, &groups)) 980 nlk->netlink_unbind(sock_net(sk), undo + 1); 981 } 982 983 static int netlink_bind(struct socket *sock, struct sockaddr *addr, 984 int addr_len) 985 { 986 struct sock *sk = sock->sk; 987 struct net *net = sock_net(sk); 988 struct netlink_sock *nlk = nlk_sk(sk); 989 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 990 int err = 0; 991 unsigned long groups = nladdr->nl_groups; 992 bool bound; 993 994 if (addr_len < sizeof(struct sockaddr_nl)) 995 return -EINVAL; 996 997 if (nladdr->nl_family != AF_NETLINK) 998 return -EINVAL; 999 1000 /* Only superuser is allowed to listen multicasts */ 1001 if (groups) { 1002 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) 1003 return -EPERM; 1004 err = netlink_realloc_groups(sk); 1005 if (err) 1006 return err; 1007 } 1008 1009 if (nlk->ngroups < BITS_PER_LONG) 1010 groups &= (1UL << nlk->ngroups) - 1; 1011 1012 bound = nlk->bound; 1013 if (bound) { 1014 /* Ensure nlk->portid is up-to-date. */ 1015 smp_rmb(); 1016 1017 if (nladdr->nl_pid != nlk->portid) 1018 return -EINVAL; 1019 } 1020 1021 netlink_lock_table(); 1022 if (nlk->netlink_bind && groups) { 1023 int group; 1024 1025 for (group = 0; group < nlk->ngroups; group++) { 1026 if (!test_bit(group, &groups)) 1027 continue; 1028 err = nlk->netlink_bind(net, group + 1); 1029 if (!err) 1030 continue; 1031 netlink_undo_bind(group, groups, sk); 1032 goto unlock; 1033 } 1034 } 1035 1036 /* No need for barriers here as we return to user-space without 1037 * using any of the bound attributes. 1038 */ 1039 if (!bound) { 1040 err = nladdr->nl_pid ? 1041 netlink_insert(sk, nladdr->nl_pid) : 1042 netlink_autobind(sock); 1043 if (err) { 1044 netlink_undo_bind(nlk->ngroups, groups, sk); 1045 goto unlock; 1046 } 1047 } 1048 1049 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) 1050 goto unlock; 1051 netlink_unlock_table(); 1052 1053 netlink_table_grab(); 1054 netlink_update_subscriptions(sk, nlk->subscriptions + 1055 hweight32(groups) - 1056 hweight32(nlk->groups[0])); 1057 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups; 1058 netlink_update_listeners(sk); 1059 netlink_table_ungrab(); 1060 1061 return 0; 1062 1063 unlock: 1064 netlink_unlock_table(); 1065 return err; 1066 } 1067 1068 static int netlink_connect(struct socket *sock, struct sockaddr *addr, 1069 int alen, int flags) 1070 { 1071 int err = 0; 1072 struct sock *sk = sock->sk; 1073 struct netlink_sock *nlk = nlk_sk(sk); 1074 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 1075 1076 if (alen < sizeof(addr->sa_family)) 1077 return -EINVAL; 1078 1079 if (addr->sa_family == AF_UNSPEC) { 1080 sk->sk_state = NETLINK_UNCONNECTED; 1081 nlk->dst_portid = 0; 1082 nlk->dst_group = 0; 1083 return 0; 1084 } 1085 if (addr->sa_family != AF_NETLINK) 1086 return -EINVAL; 1087 1088 if (alen < sizeof(struct sockaddr_nl)) 1089 return -EINVAL; 1090 1091 if ((nladdr->nl_groups || nladdr->nl_pid) && 1092 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) 1093 return -EPERM; 1094 1095 /* No need for barriers here as we return to user-space without 1096 * using any of the bound attributes. 1097 */ 1098 if (!nlk->bound) 1099 err = netlink_autobind(sock); 1100 1101 if (err == 0) { 1102 sk->sk_state = NETLINK_CONNECTED; 1103 nlk->dst_portid = nladdr->nl_pid; 1104 nlk->dst_group = ffs(nladdr->nl_groups); 1105 } 1106 1107 return err; 1108 } 1109 1110 static int netlink_getname(struct socket *sock, struct sockaddr *addr, 1111 int peer) 1112 { 1113 struct sock *sk = sock->sk; 1114 struct netlink_sock *nlk = nlk_sk(sk); 1115 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr); 1116 1117 nladdr->nl_family = AF_NETLINK; 1118 nladdr->nl_pad = 0; 1119 1120 if (peer) { 1121 nladdr->nl_pid = nlk->dst_portid; 1122 nladdr->nl_groups = netlink_group_mask(nlk->dst_group); 1123 } else { 1124 nladdr->nl_pid = nlk->portid; 1125 netlink_lock_table(); 1126 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; 1127 netlink_unlock_table(); 1128 } 1129 return sizeof(*nladdr); 1130 } 1131 1132 static int netlink_ioctl(struct socket *sock, unsigned int cmd, 1133 unsigned long arg) 1134 { 1135 /* try to hand this ioctl down to the NIC drivers. 1136 */ 1137 return -ENOIOCTLCMD; 1138 } 1139 1140 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid) 1141 { 1142 struct sock *sock; 1143 struct netlink_sock *nlk; 1144 1145 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid); 1146 if (!sock) 1147 return ERR_PTR(-ECONNREFUSED); 1148 1149 /* Don't bother queuing skb if kernel socket has no input function */ 1150 nlk = nlk_sk(sock); 1151 if (sock->sk_state == NETLINK_CONNECTED && 1152 nlk->dst_portid != nlk_sk(ssk)->portid) { 1153 sock_put(sock); 1154 return ERR_PTR(-ECONNREFUSED); 1155 } 1156 return sock; 1157 } 1158 1159 struct sock *netlink_getsockbyfilp(struct file *filp) 1160 { 1161 struct inode *inode = file_inode(filp); 1162 struct sock *sock; 1163 1164 if (!S_ISSOCK(inode->i_mode)) 1165 return ERR_PTR(-ENOTSOCK); 1166 1167 sock = SOCKET_I(inode)->sk; 1168 if (sock->sk_family != AF_NETLINK) 1169 return ERR_PTR(-EINVAL); 1170 1171 sock_hold(sock); 1172 return sock; 1173 } 1174 1175 static struct sk_buff *netlink_alloc_large_skb(unsigned int size, 1176 int broadcast) 1177 { 1178 struct sk_buff *skb; 1179 void *data; 1180 1181 if (size <= NLMSG_GOODSIZE || broadcast) 1182 return alloc_skb(size, GFP_KERNEL); 1183 1184 size = SKB_DATA_ALIGN(size) + 1185 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 1186 1187 data = vmalloc(size); 1188 if (data == NULL) 1189 return NULL; 1190 1191 skb = __build_skb(data, size); 1192 if (skb == NULL) 1193 vfree(data); 1194 else 1195 skb->destructor = netlink_skb_destructor; 1196 1197 return skb; 1198 } 1199 1200 /* 1201 * Attach a skb to a netlink socket. 1202 * The caller must hold a reference to the destination socket. On error, the 1203 * reference is dropped. The skb is not send to the destination, just all 1204 * all error checks are performed and memory in the queue is reserved. 1205 * Return values: 1206 * < 0: error. skb freed, reference to sock dropped. 1207 * 0: continue 1208 * 1: repeat lookup - reference dropped while waiting for socket memory. 1209 */ 1210 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, 1211 long *timeo, struct sock *ssk) 1212 { 1213 struct netlink_sock *nlk; 1214 1215 nlk = nlk_sk(sk); 1216 1217 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 1218 test_bit(NETLINK_S_CONGESTED, &nlk->state))) { 1219 DECLARE_WAITQUEUE(wait, current); 1220 if (!*timeo) { 1221 if (!ssk || netlink_is_kernel(ssk)) 1222 netlink_overrun(sk); 1223 sock_put(sk); 1224 kfree_skb(skb); 1225 return -EAGAIN; 1226 } 1227 1228 __set_current_state(TASK_INTERRUPTIBLE); 1229 add_wait_queue(&nlk->wait, &wait); 1230 1231 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 1232 test_bit(NETLINK_S_CONGESTED, &nlk->state)) && 1233 !sock_flag(sk, SOCK_DEAD)) 1234 *timeo = schedule_timeout(*timeo); 1235 1236 __set_current_state(TASK_RUNNING); 1237 remove_wait_queue(&nlk->wait, &wait); 1238 sock_put(sk); 1239 1240 if (signal_pending(current)) { 1241 kfree_skb(skb); 1242 return sock_intr_errno(*timeo); 1243 } 1244 return 1; 1245 } 1246 netlink_skb_set_owner_r(skb, sk); 1247 return 0; 1248 } 1249 1250 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb) 1251 { 1252 int len = skb->len; 1253 1254 netlink_deliver_tap(sock_net(sk), skb); 1255 1256 skb_queue_tail(&sk->sk_receive_queue, skb); 1257 sk->sk_data_ready(sk); 1258 return len; 1259 } 1260 1261 int netlink_sendskb(struct sock *sk, struct sk_buff *skb) 1262 { 1263 int len = __netlink_sendskb(sk, skb); 1264 1265 sock_put(sk); 1266 return len; 1267 } 1268 1269 void netlink_detachskb(struct sock *sk, struct sk_buff *skb) 1270 { 1271 kfree_skb(skb); 1272 sock_put(sk); 1273 } 1274 1275 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation) 1276 { 1277 int delta; 1278 1279 WARN_ON(skb->sk != NULL); 1280 delta = skb->end - skb->tail; 1281 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize) 1282 return skb; 1283 1284 if (skb_shared(skb)) { 1285 struct sk_buff *nskb = skb_clone(skb, allocation); 1286 if (!nskb) 1287 return skb; 1288 consume_skb(skb); 1289 skb = nskb; 1290 } 1291 1292 pskb_expand_head(skb, 0, -delta, 1293 (allocation & ~__GFP_DIRECT_RECLAIM) | 1294 __GFP_NOWARN | __GFP_NORETRY); 1295 return skb; 1296 } 1297 1298 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb, 1299 struct sock *ssk) 1300 { 1301 int ret; 1302 struct netlink_sock *nlk = nlk_sk(sk); 1303 1304 ret = -ECONNREFUSED; 1305 if (nlk->netlink_rcv != NULL) { 1306 ret = skb->len; 1307 netlink_skb_set_owner_r(skb, sk); 1308 NETLINK_CB(skb).sk = ssk; 1309 netlink_deliver_tap_kernel(sk, ssk, skb); 1310 nlk->netlink_rcv(skb); 1311 consume_skb(skb); 1312 } else { 1313 kfree_skb(skb); 1314 } 1315 sock_put(sk); 1316 return ret; 1317 } 1318 1319 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, 1320 u32 portid, int nonblock) 1321 { 1322 struct sock *sk; 1323 int err; 1324 long timeo; 1325 1326 skb = netlink_trim(skb, gfp_any()); 1327 1328 timeo = sock_sndtimeo(ssk, nonblock); 1329 retry: 1330 sk = netlink_getsockbyportid(ssk, portid); 1331 if (IS_ERR(sk)) { 1332 kfree_skb(skb); 1333 return PTR_ERR(sk); 1334 } 1335 if (netlink_is_kernel(sk)) 1336 return netlink_unicast_kernel(sk, skb, ssk); 1337 1338 if (sk_filter(sk, skb)) { 1339 err = skb->len; 1340 kfree_skb(skb); 1341 sock_put(sk); 1342 return err; 1343 } 1344 1345 err = netlink_attachskb(sk, skb, &timeo, ssk); 1346 if (err == 1) 1347 goto retry; 1348 if (err) 1349 return err; 1350 1351 return netlink_sendskb(sk, skb); 1352 } 1353 EXPORT_SYMBOL(netlink_unicast); 1354 1355 int netlink_has_listeners(struct sock *sk, unsigned int group) 1356 { 1357 int res = 0; 1358 struct listeners *listeners; 1359 1360 BUG_ON(!netlink_is_kernel(sk)); 1361 1362 rcu_read_lock(); 1363 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners); 1364 1365 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups) 1366 res = test_bit(group - 1, listeners->masks); 1367 1368 rcu_read_unlock(); 1369 1370 return res; 1371 } 1372 EXPORT_SYMBOL_GPL(netlink_has_listeners); 1373 1374 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) 1375 { 1376 struct netlink_sock *nlk = nlk_sk(sk); 1377 1378 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && 1379 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) { 1380 netlink_skb_set_owner_r(skb, sk); 1381 __netlink_sendskb(sk, skb); 1382 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1); 1383 } 1384 return -1; 1385 } 1386 1387 struct netlink_broadcast_data { 1388 struct sock *exclude_sk; 1389 struct net *net; 1390 u32 portid; 1391 u32 group; 1392 int failure; 1393 int delivery_failure; 1394 int congested; 1395 int delivered; 1396 gfp_t allocation; 1397 struct sk_buff *skb, *skb2; 1398 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data); 1399 void *tx_data; 1400 }; 1401 1402 static void do_one_broadcast(struct sock *sk, 1403 struct netlink_broadcast_data *p) 1404 { 1405 struct netlink_sock *nlk = nlk_sk(sk); 1406 int val; 1407 1408 if (p->exclude_sk == sk) 1409 return; 1410 1411 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups || 1412 !test_bit(p->group - 1, nlk->groups)) 1413 return; 1414 1415 if (!net_eq(sock_net(sk), p->net)) { 1416 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID)) 1417 return; 1418 1419 if (!peernet_has_id(sock_net(sk), p->net)) 1420 return; 1421 1422 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns, 1423 CAP_NET_BROADCAST)) 1424 return; 1425 } 1426 1427 if (p->failure) { 1428 netlink_overrun(sk); 1429 return; 1430 } 1431 1432 sock_hold(sk); 1433 if (p->skb2 == NULL) { 1434 if (skb_shared(p->skb)) { 1435 p->skb2 = skb_clone(p->skb, p->allocation); 1436 } else { 1437 p->skb2 = skb_get(p->skb); 1438 /* 1439 * skb ownership may have been set when 1440 * delivered to a previous socket. 1441 */ 1442 skb_orphan(p->skb2); 1443 } 1444 } 1445 if (p->skb2 == NULL) { 1446 netlink_overrun(sk); 1447 /* Clone failed. Notify ALL listeners. */ 1448 p->failure = 1; 1449 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR) 1450 p->delivery_failure = 1; 1451 goto out; 1452 } 1453 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) { 1454 kfree_skb(p->skb2); 1455 p->skb2 = NULL; 1456 goto out; 1457 } 1458 if (sk_filter(sk, p->skb2)) { 1459 kfree_skb(p->skb2); 1460 p->skb2 = NULL; 1461 goto out; 1462 } 1463 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net); 1464 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED) 1465 NETLINK_CB(p->skb2).nsid_is_set = true; 1466 val = netlink_broadcast_deliver(sk, p->skb2); 1467 if (val < 0) { 1468 netlink_overrun(sk); 1469 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR) 1470 p->delivery_failure = 1; 1471 } else { 1472 p->congested |= val; 1473 p->delivered = 1; 1474 p->skb2 = NULL; 1475 } 1476 out: 1477 sock_put(sk); 1478 } 1479 1480 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid, 1481 u32 group, gfp_t allocation, 1482 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data), 1483 void *filter_data) 1484 { 1485 struct net *net = sock_net(ssk); 1486 struct netlink_broadcast_data info; 1487 struct sock *sk; 1488 1489 skb = netlink_trim(skb, allocation); 1490 1491 info.exclude_sk = ssk; 1492 info.net = net; 1493 info.portid = portid; 1494 info.group = group; 1495 info.failure = 0; 1496 info.delivery_failure = 0; 1497 info.congested = 0; 1498 info.delivered = 0; 1499 info.allocation = allocation; 1500 info.skb = skb; 1501 info.skb2 = NULL; 1502 info.tx_filter = filter; 1503 info.tx_data = filter_data; 1504 1505 /* While we sleep in clone, do not allow to change socket list */ 1506 1507 netlink_lock_table(); 1508 1509 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) 1510 do_one_broadcast(sk, &info); 1511 1512 consume_skb(skb); 1513 1514 netlink_unlock_table(); 1515 1516 if (info.delivery_failure) { 1517 kfree_skb(info.skb2); 1518 return -ENOBUFS; 1519 } 1520 consume_skb(info.skb2); 1521 1522 if (info.delivered) { 1523 if (info.congested && gfpflags_allow_blocking(allocation)) 1524 yield(); 1525 return 0; 1526 } 1527 return -ESRCH; 1528 } 1529 EXPORT_SYMBOL(netlink_broadcast_filtered); 1530 1531 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid, 1532 u32 group, gfp_t allocation) 1533 { 1534 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation, 1535 NULL, NULL); 1536 } 1537 EXPORT_SYMBOL(netlink_broadcast); 1538 1539 struct netlink_set_err_data { 1540 struct sock *exclude_sk; 1541 u32 portid; 1542 u32 group; 1543 int code; 1544 }; 1545 1546 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p) 1547 { 1548 struct netlink_sock *nlk = nlk_sk(sk); 1549 int ret = 0; 1550 1551 if (sk == p->exclude_sk) 1552 goto out; 1553 1554 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk))) 1555 goto out; 1556 1557 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups || 1558 !test_bit(p->group - 1, nlk->groups)) 1559 goto out; 1560 1561 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) { 1562 ret = 1; 1563 goto out; 1564 } 1565 1566 sk->sk_err = p->code; 1567 sk->sk_error_report(sk); 1568 out: 1569 return ret; 1570 } 1571 1572 /** 1573 * netlink_set_err - report error to broadcast listeners 1574 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create() 1575 * @portid: the PORTID of a process that we want to skip (if any) 1576 * @group: the broadcast group that will notice the error 1577 * @code: error code, must be negative (as usual in kernelspace) 1578 * 1579 * This function returns the number of broadcast listeners that have set the 1580 * NETLINK_NO_ENOBUFS socket option. 1581 */ 1582 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code) 1583 { 1584 struct netlink_set_err_data info; 1585 struct sock *sk; 1586 int ret = 0; 1587 1588 info.exclude_sk = ssk; 1589 info.portid = portid; 1590 info.group = group; 1591 /* sk->sk_err wants a positive error value */ 1592 info.code = -code; 1593 1594 read_lock(&nl_table_lock); 1595 1596 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) 1597 ret += do_one_set_err(sk, &info); 1598 1599 read_unlock(&nl_table_lock); 1600 return ret; 1601 } 1602 EXPORT_SYMBOL(netlink_set_err); 1603 1604 /* must be called with netlink table grabbed */ 1605 static void netlink_update_socket_mc(struct netlink_sock *nlk, 1606 unsigned int group, 1607 int is_new) 1608 { 1609 int old, new = !!is_new, subscriptions; 1610 1611 old = test_bit(group - 1, nlk->groups); 1612 subscriptions = nlk->subscriptions - old + new; 1613 if (new) 1614 __set_bit(group - 1, nlk->groups); 1615 else 1616 __clear_bit(group - 1, nlk->groups); 1617 netlink_update_subscriptions(&nlk->sk, subscriptions); 1618 netlink_update_listeners(&nlk->sk); 1619 } 1620 1621 static int netlink_setsockopt(struct socket *sock, int level, int optname, 1622 char __user *optval, unsigned int optlen) 1623 { 1624 struct sock *sk = sock->sk; 1625 struct netlink_sock *nlk = nlk_sk(sk); 1626 unsigned int val = 0; 1627 int err; 1628 1629 if (level != SOL_NETLINK) 1630 return -ENOPROTOOPT; 1631 1632 if (optlen >= sizeof(int) && 1633 get_user(val, (unsigned int __user *)optval)) 1634 return -EFAULT; 1635 1636 switch (optname) { 1637 case NETLINK_PKTINFO: 1638 if (val) 1639 nlk->flags |= NETLINK_F_RECV_PKTINFO; 1640 else 1641 nlk->flags &= ~NETLINK_F_RECV_PKTINFO; 1642 err = 0; 1643 break; 1644 case NETLINK_ADD_MEMBERSHIP: 1645 case NETLINK_DROP_MEMBERSHIP: { 1646 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) 1647 return -EPERM; 1648 err = netlink_realloc_groups(sk); 1649 if (err) 1650 return err; 1651 if (!val || val - 1 >= nlk->ngroups) 1652 return -EINVAL; 1653 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) { 1654 err = nlk->netlink_bind(sock_net(sk), val); 1655 if (err) 1656 return err; 1657 } 1658 netlink_table_grab(); 1659 netlink_update_socket_mc(nlk, val, 1660 optname == NETLINK_ADD_MEMBERSHIP); 1661 netlink_table_ungrab(); 1662 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind) 1663 nlk->netlink_unbind(sock_net(sk), val); 1664 1665 err = 0; 1666 break; 1667 } 1668 case NETLINK_BROADCAST_ERROR: 1669 if (val) 1670 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR; 1671 else 1672 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR; 1673 err = 0; 1674 break; 1675 case NETLINK_NO_ENOBUFS: 1676 if (val) { 1677 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS; 1678 clear_bit(NETLINK_S_CONGESTED, &nlk->state); 1679 wake_up_interruptible(&nlk->wait); 1680 } else { 1681 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS; 1682 } 1683 err = 0; 1684 break; 1685 case NETLINK_LISTEN_ALL_NSID: 1686 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST)) 1687 return -EPERM; 1688 1689 if (val) 1690 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID; 1691 else 1692 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID; 1693 err = 0; 1694 break; 1695 case NETLINK_CAP_ACK: 1696 if (val) 1697 nlk->flags |= NETLINK_F_CAP_ACK; 1698 else 1699 nlk->flags &= ~NETLINK_F_CAP_ACK; 1700 err = 0; 1701 break; 1702 case NETLINK_EXT_ACK: 1703 if (val) 1704 nlk->flags |= NETLINK_F_EXT_ACK; 1705 else 1706 nlk->flags &= ~NETLINK_F_EXT_ACK; 1707 err = 0; 1708 break; 1709 case NETLINK_GET_STRICT_CHK: 1710 if (val) 1711 nlk->flags |= NETLINK_F_STRICT_CHK; 1712 else 1713 nlk->flags &= ~NETLINK_F_STRICT_CHK; 1714 err = 0; 1715 break; 1716 default: 1717 err = -ENOPROTOOPT; 1718 } 1719 return err; 1720 } 1721 1722 static int netlink_getsockopt(struct socket *sock, int level, int optname, 1723 char __user *optval, int __user *optlen) 1724 { 1725 struct sock *sk = sock->sk; 1726 struct netlink_sock *nlk = nlk_sk(sk); 1727 int len, val, err; 1728 1729 if (level != SOL_NETLINK) 1730 return -ENOPROTOOPT; 1731 1732 if (get_user(len, optlen)) 1733 return -EFAULT; 1734 if (len < 0) 1735 return -EINVAL; 1736 1737 switch (optname) { 1738 case NETLINK_PKTINFO: 1739 if (len < sizeof(int)) 1740 return -EINVAL; 1741 len = sizeof(int); 1742 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0; 1743 if (put_user(len, optlen) || 1744 put_user(val, optval)) 1745 return -EFAULT; 1746 err = 0; 1747 break; 1748 case NETLINK_BROADCAST_ERROR: 1749 if (len < sizeof(int)) 1750 return -EINVAL; 1751 len = sizeof(int); 1752 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0; 1753 if (put_user(len, optlen) || 1754 put_user(val, optval)) 1755 return -EFAULT; 1756 err = 0; 1757 break; 1758 case NETLINK_NO_ENOBUFS: 1759 if (len < sizeof(int)) 1760 return -EINVAL; 1761 len = sizeof(int); 1762 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0; 1763 if (put_user(len, optlen) || 1764 put_user(val, optval)) 1765 return -EFAULT; 1766 err = 0; 1767 break; 1768 case NETLINK_LIST_MEMBERSHIPS: { 1769 int pos, idx, shift; 1770 1771 err = 0; 1772 netlink_lock_table(); 1773 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) { 1774 if (len - pos < sizeof(u32)) 1775 break; 1776 1777 idx = pos / sizeof(unsigned long); 1778 shift = (pos % sizeof(unsigned long)) * 8; 1779 if (put_user((u32)(nlk->groups[idx] >> shift), 1780 (u32 __user *)(optval + pos))) { 1781 err = -EFAULT; 1782 break; 1783 } 1784 } 1785 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen)) 1786 err = -EFAULT; 1787 netlink_unlock_table(); 1788 break; 1789 } 1790 case NETLINK_CAP_ACK: 1791 if (len < sizeof(int)) 1792 return -EINVAL; 1793 len = sizeof(int); 1794 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0; 1795 if (put_user(len, optlen) || 1796 put_user(val, optval)) 1797 return -EFAULT; 1798 err = 0; 1799 break; 1800 case NETLINK_EXT_ACK: 1801 if (len < sizeof(int)) 1802 return -EINVAL; 1803 len = sizeof(int); 1804 val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0; 1805 if (put_user(len, optlen) || put_user(val, optval)) 1806 return -EFAULT; 1807 err = 0; 1808 break; 1809 case NETLINK_GET_STRICT_CHK: 1810 if (len < sizeof(int)) 1811 return -EINVAL; 1812 len = sizeof(int); 1813 val = nlk->flags & NETLINK_F_STRICT_CHK ? 1 : 0; 1814 if (put_user(len, optlen) || put_user(val, optval)) 1815 return -EFAULT; 1816 err = 0; 1817 break; 1818 default: 1819 err = -ENOPROTOOPT; 1820 } 1821 return err; 1822 } 1823 1824 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) 1825 { 1826 struct nl_pktinfo info; 1827 1828 info.group = NETLINK_CB(skb).dst_group; 1829 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); 1830 } 1831 1832 static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg, 1833 struct sk_buff *skb) 1834 { 1835 if (!NETLINK_CB(skb).nsid_is_set) 1836 return; 1837 1838 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int), 1839 &NETLINK_CB(skb).nsid); 1840 } 1841 1842 static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 1843 { 1844 struct sock *sk = sock->sk; 1845 struct netlink_sock *nlk = nlk_sk(sk); 1846 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); 1847 u32 dst_portid; 1848 u32 dst_group; 1849 struct sk_buff *skb; 1850 int err; 1851 struct scm_cookie scm; 1852 u32 netlink_skb_flags = 0; 1853 1854 if (msg->msg_flags&MSG_OOB) 1855 return -EOPNOTSUPP; 1856 1857 err = scm_send(sock, msg, &scm, true); 1858 if (err < 0) 1859 return err; 1860 1861 if (msg->msg_namelen) { 1862 err = -EINVAL; 1863 if (msg->msg_namelen < sizeof(struct sockaddr_nl)) 1864 goto out; 1865 if (addr->nl_family != AF_NETLINK) 1866 goto out; 1867 dst_portid = addr->nl_pid; 1868 dst_group = ffs(addr->nl_groups); 1869 err = -EPERM; 1870 if ((dst_group || dst_portid) && 1871 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) 1872 goto out; 1873 netlink_skb_flags |= NETLINK_SKB_DST; 1874 } else { 1875 dst_portid = nlk->dst_portid; 1876 dst_group = nlk->dst_group; 1877 } 1878 1879 if (!nlk->bound) { 1880 err = netlink_autobind(sock); 1881 if (err) 1882 goto out; 1883 } else { 1884 /* Ensure nlk is hashed and visible. */ 1885 smp_rmb(); 1886 } 1887 1888 err = -EMSGSIZE; 1889 if (len > sk->sk_sndbuf - 32) 1890 goto out; 1891 err = -ENOBUFS; 1892 skb = netlink_alloc_large_skb(len, dst_group); 1893 if (skb == NULL) 1894 goto out; 1895 1896 NETLINK_CB(skb).portid = nlk->portid; 1897 NETLINK_CB(skb).dst_group = dst_group; 1898 NETLINK_CB(skb).creds = scm.creds; 1899 NETLINK_CB(skb).flags = netlink_skb_flags; 1900 1901 err = -EFAULT; 1902 if (memcpy_from_msg(skb_put(skb, len), msg, len)) { 1903 kfree_skb(skb); 1904 goto out; 1905 } 1906 1907 err = security_netlink_send(sk, skb); 1908 if (err) { 1909 kfree_skb(skb); 1910 goto out; 1911 } 1912 1913 if (dst_group) { 1914 refcount_inc(&skb->users); 1915 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL); 1916 } 1917 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT); 1918 1919 out: 1920 scm_destroy(&scm); 1921 return err; 1922 } 1923 1924 static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 1925 int flags) 1926 { 1927 struct scm_cookie scm; 1928 struct sock *sk = sock->sk; 1929 struct netlink_sock *nlk = nlk_sk(sk); 1930 int noblock = flags&MSG_DONTWAIT; 1931 size_t copied; 1932 struct sk_buff *skb, *data_skb; 1933 int err, ret; 1934 1935 if (flags&MSG_OOB) 1936 return -EOPNOTSUPP; 1937 1938 copied = 0; 1939 1940 skb = skb_recv_datagram(sk, flags, noblock, &err); 1941 if (skb == NULL) 1942 goto out; 1943 1944 data_skb = skb; 1945 1946 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES 1947 if (unlikely(skb_shinfo(skb)->frag_list)) { 1948 /* 1949 * If this skb has a frag_list, then here that means that we 1950 * will have to use the frag_list skb's data for compat tasks 1951 * and the regular skb's data for normal (non-compat) tasks. 1952 * 1953 * If we need to send the compat skb, assign it to the 1954 * 'data_skb' variable so that it will be used below for data 1955 * copying. We keep 'skb' for everything else, including 1956 * freeing both later. 1957 */ 1958 if (flags & MSG_CMSG_COMPAT) 1959 data_skb = skb_shinfo(skb)->frag_list; 1960 } 1961 #endif 1962 1963 /* Record the max length of recvmsg() calls for future allocations */ 1964 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len); 1965 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len, 1966 SKB_WITH_OVERHEAD(32768)); 1967 1968 copied = data_skb->len; 1969 if (len < copied) { 1970 msg->msg_flags |= MSG_TRUNC; 1971 copied = len; 1972 } 1973 1974 skb_reset_transport_header(data_skb); 1975 err = skb_copy_datagram_msg(data_skb, 0, msg, copied); 1976 1977 if (msg->msg_name) { 1978 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); 1979 addr->nl_family = AF_NETLINK; 1980 addr->nl_pad = 0; 1981 addr->nl_pid = NETLINK_CB(skb).portid; 1982 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); 1983 msg->msg_namelen = sizeof(*addr); 1984 } 1985 1986 if (nlk->flags & NETLINK_F_RECV_PKTINFO) 1987 netlink_cmsg_recv_pktinfo(msg, skb); 1988 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID) 1989 netlink_cmsg_listen_all_nsid(sk, msg, skb); 1990 1991 memset(&scm, 0, sizeof(scm)); 1992 scm.creds = *NETLINK_CREDS(skb); 1993 if (flags & MSG_TRUNC) 1994 copied = data_skb->len; 1995 1996 skb_free_datagram(sk, skb); 1997 1998 if (nlk->cb_running && 1999 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { 2000 ret = netlink_dump(sk); 2001 if (ret) { 2002 sk->sk_err = -ret; 2003 sk->sk_error_report(sk); 2004 } 2005 } 2006 2007 scm_recv(sock, msg, &scm, flags); 2008 out: 2009 netlink_rcv_wake(sk); 2010 return err ? : copied; 2011 } 2012 2013 static void netlink_data_ready(struct sock *sk) 2014 { 2015 BUG(); 2016 } 2017 2018 /* 2019 * We export these functions to other modules. They provide a 2020 * complete set of kernel non-blocking support for message 2021 * queueing. 2022 */ 2023 2024 struct sock * 2025 __netlink_kernel_create(struct net *net, int unit, struct module *module, 2026 struct netlink_kernel_cfg *cfg) 2027 { 2028 struct socket *sock; 2029 struct sock *sk; 2030 struct netlink_sock *nlk; 2031 struct listeners *listeners = NULL; 2032 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL; 2033 unsigned int groups; 2034 2035 BUG_ON(!nl_table); 2036 2037 if (unit < 0 || unit >= MAX_LINKS) 2038 return NULL; 2039 2040 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) 2041 return NULL; 2042 2043 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0) 2044 goto out_sock_release_nosk; 2045 2046 sk = sock->sk; 2047 2048 if (!cfg || cfg->groups < 32) 2049 groups = 32; 2050 else 2051 groups = cfg->groups; 2052 2053 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2054 if (!listeners) 2055 goto out_sock_release; 2056 2057 sk->sk_data_ready = netlink_data_ready; 2058 if (cfg && cfg->input) 2059 nlk_sk(sk)->netlink_rcv = cfg->input; 2060 2061 if (netlink_insert(sk, 0)) 2062 goto out_sock_release; 2063 2064 nlk = nlk_sk(sk); 2065 nlk->flags |= NETLINK_F_KERNEL_SOCKET; 2066 2067 netlink_table_grab(); 2068 if (!nl_table[unit].registered) { 2069 nl_table[unit].groups = groups; 2070 rcu_assign_pointer(nl_table[unit].listeners, listeners); 2071 nl_table[unit].cb_mutex = cb_mutex; 2072 nl_table[unit].module = module; 2073 if (cfg) { 2074 nl_table[unit].bind = cfg->bind; 2075 nl_table[unit].unbind = cfg->unbind; 2076 nl_table[unit].flags = cfg->flags; 2077 if (cfg->compare) 2078 nl_table[unit].compare = cfg->compare; 2079 } 2080 nl_table[unit].registered = 1; 2081 } else { 2082 kfree(listeners); 2083 nl_table[unit].registered++; 2084 } 2085 netlink_table_ungrab(); 2086 return sk; 2087 2088 out_sock_release: 2089 kfree(listeners); 2090 netlink_kernel_release(sk); 2091 return NULL; 2092 2093 out_sock_release_nosk: 2094 sock_release(sock); 2095 return NULL; 2096 } 2097 EXPORT_SYMBOL(__netlink_kernel_create); 2098 2099 void 2100 netlink_kernel_release(struct sock *sk) 2101 { 2102 if (sk == NULL || sk->sk_socket == NULL) 2103 return; 2104 2105 sock_release(sk->sk_socket); 2106 } 2107 EXPORT_SYMBOL(netlink_kernel_release); 2108 2109 int __netlink_change_ngroups(struct sock *sk, unsigned int groups) 2110 { 2111 struct listeners *new, *old; 2112 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 2113 2114 if (groups < 32) 2115 groups = 32; 2116 2117 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) { 2118 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC); 2119 if (!new) 2120 return -ENOMEM; 2121 old = nl_deref_protected(tbl->listeners); 2122 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups)); 2123 rcu_assign_pointer(tbl->listeners, new); 2124 2125 kfree_rcu(old, rcu); 2126 } 2127 tbl->groups = groups; 2128 2129 return 0; 2130 } 2131 2132 /** 2133 * netlink_change_ngroups - change number of multicast groups 2134 * 2135 * This changes the number of multicast groups that are available 2136 * on a certain netlink family. Note that it is not possible to 2137 * change the number of groups to below 32. Also note that it does 2138 * not implicitly call netlink_clear_multicast_users() when the 2139 * number of groups is reduced. 2140 * 2141 * @sk: The kernel netlink socket, as returned by netlink_kernel_create(). 2142 * @groups: The new number of groups. 2143 */ 2144 int netlink_change_ngroups(struct sock *sk, unsigned int groups) 2145 { 2146 int err; 2147 2148 netlink_table_grab(); 2149 err = __netlink_change_ngroups(sk, groups); 2150 netlink_table_ungrab(); 2151 2152 return err; 2153 } 2154 2155 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group) 2156 { 2157 struct sock *sk; 2158 struct netlink_table *tbl = &nl_table[ksk->sk_protocol]; 2159 2160 sk_for_each_bound(sk, &tbl->mc_list) 2161 netlink_update_socket_mc(nlk_sk(sk), group, 0); 2162 } 2163 2164 struct nlmsghdr * 2165 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags) 2166 { 2167 struct nlmsghdr *nlh; 2168 int size = nlmsg_msg_size(len); 2169 2170 nlh = skb_put(skb, NLMSG_ALIGN(size)); 2171 nlh->nlmsg_type = type; 2172 nlh->nlmsg_len = size; 2173 nlh->nlmsg_flags = flags; 2174 nlh->nlmsg_pid = portid; 2175 nlh->nlmsg_seq = seq; 2176 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0) 2177 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size); 2178 return nlh; 2179 } 2180 EXPORT_SYMBOL(__nlmsg_put); 2181 2182 /* 2183 * It looks a bit ugly. 2184 * It would be better to create kernel thread. 2185 */ 2186 2187 static int netlink_dump(struct sock *sk) 2188 { 2189 struct netlink_sock *nlk = nlk_sk(sk); 2190 struct netlink_ext_ack extack = {}; 2191 struct netlink_callback *cb; 2192 struct sk_buff *skb = NULL; 2193 struct nlmsghdr *nlh; 2194 struct module *module; 2195 int err = -ENOBUFS; 2196 int alloc_min_size; 2197 int alloc_size; 2198 2199 mutex_lock(nlk->cb_mutex); 2200 if (!nlk->cb_running) { 2201 err = -EINVAL; 2202 goto errout_skb; 2203 } 2204 2205 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) 2206 goto errout_skb; 2207 2208 /* NLMSG_GOODSIZE is small to avoid high order allocations being 2209 * required, but it makes sense to _attempt_ a 16K bytes allocation 2210 * to reduce number of system calls on dump operations, if user 2211 * ever provided a big enough buffer. 2212 */ 2213 cb = &nlk->cb; 2214 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); 2215 2216 if (alloc_min_size < nlk->max_recvmsg_len) { 2217 alloc_size = nlk->max_recvmsg_len; 2218 skb = alloc_skb(alloc_size, 2219 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) | 2220 __GFP_NOWARN | __GFP_NORETRY); 2221 } 2222 if (!skb) { 2223 alloc_size = alloc_min_size; 2224 skb = alloc_skb(alloc_size, GFP_KERNEL); 2225 } 2226 if (!skb) 2227 goto errout_skb; 2228 2229 /* Trim skb to allocated size. User is expected to provide buffer as 2230 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at 2231 * netlink_recvmsg())). dump will pack as many smaller messages as 2232 * could fit within the allocated skb. skb is typically allocated 2233 * with larger space than required (could be as much as near 2x the 2234 * requested size with align to next power of 2 approach). Allowing 2235 * dump to use the excess space makes it difficult for a user to have a 2236 * reasonable static buffer based on the expected largest dump of a 2237 * single netdev. The outcome is MSG_TRUNC error. 2238 */ 2239 skb_reserve(skb, skb_tailroom(skb) - alloc_size); 2240 netlink_skb_set_owner_r(skb, sk); 2241 2242 if (nlk->dump_done_errno > 0) { 2243 cb->extack = &extack; 2244 nlk->dump_done_errno = cb->dump(skb, cb); 2245 cb->extack = NULL; 2246 } 2247 2248 if (nlk->dump_done_errno > 0 || 2249 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) { 2250 mutex_unlock(nlk->cb_mutex); 2251 2252 if (sk_filter(sk, skb)) 2253 kfree_skb(skb); 2254 else 2255 __netlink_sendskb(sk, skb); 2256 return 0; 2257 } 2258 2259 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, 2260 sizeof(nlk->dump_done_errno), 2261 NLM_F_MULTI | cb->answer_flags); 2262 if (WARN_ON(!nlh)) 2263 goto errout_skb; 2264 2265 nl_dump_check_consistent(cb, nlh); 2266 2267 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, 2268 sizeof(nlk->dump_done_errno)); 2269 2270 if (extack._msg && nlk->flags & NETLINK_F_EXT_ACK) { 2271 nlh->nlmsg_flags |= NLM_F_ACK_TLVS; 2272 if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack._msg)) 2273 nlmsg_end(skb, nlh); 2274 } 2275 2276 if (sk_filter(sk, skb)) 2277 kfree_skb(skb); 2278 else 2279 __netlink_sendskb(sk, skb); 2280 2281 if (cb->done) 2282 cb->done(cb); 2283 2284 nlk->cb_running = false; 2285 module = cb->module; 2286 skb = cb->skb; 2287 mutex_unlock(nlk->cb_mutex); 2288 module_put(module); 2289 consume_skb(skb); 2290 return 0; 2291 2292 errout_skb: 2293 mutex_unlock(nlk->cb_mutex); 2294 kfree_skb(skb); 2295 return err; 2296 } 2297 2298 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 2299 const struct nlmsghdr *nlh, 2300 struct netlink_dump_control *control) 2301 { 2302 struct netlink_sock *nlk, *nlk2; 2303 struct netlink_callback *cb; 2304 struct sock *sk; 2305 int ret; 2306 2307 refcount_inc(&skb->users); 2308 2309 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid); 2310 if (sk == NULL) { 2311 ret = -ECONNREFUSED; 2312 goto error_free; 2313 } 2314 2315 nlk = nlk_sk(sk); 2316 mutex_lock(nlk->cb_mutex); 2317 /* A dump is in progress... */ 2318 if (nlk->cb_running) { 2319 ret = -EBUSY; 2320 goto error_unlock; 2321 } 2322 /* add reference of module which cb->dump belongs to */ 2323 if (!try_module_get(control->module)) { 2324 ret = -EPROTONOSUPPORT; 2325 goto error_unlock; 2326 } 2327 2328 cb = &nlk->cb; 2329 memset(cb, 0, sizeof(*cb)); 2330 cb->dump = control->dump; 2331 cb->done = control->done; 2332 cb->nlh = nlh; 2333 cb->data = control->data; 2334 cb->module = control->module; 2335 cb->min_dump_alloc = control->min_dump_alloc; 2336 cb->skb = skb; 2337 2338 nlk2 = nlk_sk(NETLINK_CB(skb).sk); 2339 cb->strict_check = !!(nlk2->flags & NETLINK_F_STRICT_CHK); 2340 2341 if (control->start) { 2342 ret = control->start(cb); 2343 if (ret) 2344 goto error_put; 2345 } 2346 2347 nlk->cb_running = true; 2348 nlk->dump_done_errno = INT_MAX; 2349 2350 mutex_unlock(nlk->cb_mutex); 2351 2352 ret = netlink_dump(sk); 2353 2354 sock_put(sk); 2355 2356 if (ret) 2357 return ret; 2358 2359 /* We successfully started a dump, by returning -EINTR we 2360 * signal not to send ACK even if it was requested. 2361 */ 2362 return -EINTR; 2363 2364 error_put: 2365 module_put(control->module); 2366 error_unlock: 2367 sock_put(sk); 2368 mutex_unlock(nlk->cb_mutex); 2369 error_free: 2370 kfree_skb(skb); 2371 return ret; 2372 } 2373 EXPORT_SYMBOL(__netlink_dump_start); 2374 2375 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, 2376 const struct netlink_ext_ack *extack) 2377 { 2378 struct sk_buff *skb; 2379 struct nlmsghdr *rep; 2380 struct nlmsgerr *errmsg; 2381 size_t payload = sizeof(*errmsg); 2382 size_t tlvlen = 0; 2383 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk); 2384 unsigned int flags = 0; 2385 bool nlk_has_extack = nlk->flags & NETLINK_F_EXT_ACK; 2386 2387 /* Error messages get the original request appened, unless the user 2388 * requests to cap the error message, and get extra error data if 2389 * requested. 2390 */ 2391 if (nlk_has_extack && extack && extack->_msg) 2392 tlvlen += nla_total_size(strlen(extack->_msg) + 1); 2393 2394 if (err) { 2395 if (!(nlk->flags & NETLINK_F_CAP_ACK)) 2396 payload += nlmsg_len(nlh); 2397 else 2398 flags |= NLM_F_CAPPED; 2399 if (nlk_has_extack && extack && extack->bad_attr) 2400 tlvlen += nla_total_size(sizeof(u32)); 2401 } else { 2402 flags |= NLM_F_CAPPED; 2403 2404 if (nlk_has_extack && extack && extack->cookie_len) 2405 tlvlen += nla_total_size(extack->cookie_len); 2406 } 2407 2408 if (tlvlen) 2409 flags |= NLM_F_ACK_TLVS; 2410 2411 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL); 2412 if (!skb) { 2413 NETLINK_CB(in_skb).sk->sk_err = ENOBUFS; 2414 NETLINK_CB(in_skb).sk->sk_error_report(NETLINK_CB(in_skb).sk); 2415 return; 2416 } 2417 2418 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, 2419 NLMSG_ERROR, payload, flags); 2420 errmsg = nlmsg_data(rep); 2421 errmsg->error = err; 2422 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); 2423 2424 if (nlk_has_extack && extack) { 2425 if (extack->_msg) { 2426 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, 2427 extack->_msg)); 2428 } 2429 if (err) { 2430 if (extack->bad_attr && 2431 !WARN_ON((u8 *)extack->bad_attr < in_skb->data || 2432 (u8 *)extack->bad_attr >= in_skb->data + 2433 in_skb->len)) 2434 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS, 2435 (u8 *)extack->bad_attr - 2436 in_skb->data)); 2437 } else { 2438 if (extack->cookie_len) 2439 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE, 2440 extack->cookie_len, 2441 extack->cookie)); 2442 } 2443 } 2444 2445 nlmsg_end(skb, rep); 2446 2447 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT); 2448 } 2449 EXPORT_SYMBOL(netlink_ack); 2450 2451 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, 2452 struct nlmsghdr *, 2453 struct netlink_ext_ack *)) 2454 { 2455 struct netlink_ext_ack extack; 2456 struct nlmsghdr *nlh; 2457 int err; 2458 2459 while (skb->len >= nlmsg_total_size(0)) { 2460 int msglen; 2461 2462 memset(&extack, 0, sizeof(extack)); 2463 nlh = nlmsg_hdr(skb); 2464 err = 0; 2465 2466 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) 2467 return 0; 2468 2469 /* Only requests are handled by the kernel */ 2470 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) 2471 goto ack; 2472 2473 /* Skip control messages */ 2474 if (nlh->nlmsg_type < NLMSG_MIN_TYPE) 2475 goto ack; 2476 2477 err = cb(skb, nlh, &extack); 2478 if (err == -EINTR) 2479 goto skip; 2480 2481 ack: 2482 if (nlh->nlmsg_flags & NLM_F_ACK || err) 2483 netlink_ack(skb, nlh, err, &extack); 2484 2485 skip: 2486 msglen = NLMSG_ALIGN(nlh->nlmsg_len); 2487 if (msglen > skb->len) 2488 msglen = skb->len; 2489 skb_pull(skb, msglen); 2490 } 2491 2492 return 0; 2493 } 2494 EXPORT_SYMBOL(netlink_rcv_skb); 2495 2496 /** 2497 * nlmsg_notify - send a notification netlink message 2498 * @sk: netlink socket to use 2499 * @skb: notification message 2500 * @portid: destination netlink portid for reports or 0 2501 * @group: destination multicast group or 0 2502 * @report: 1 to report back, 0 to disable 2503 * @flags: allocation flags 2504 */ 2505 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid, 2506 unsigned int group, int report, gfp_t flags) 2507 { 2508 int err = 0; 2509 2510 if (group) { 2511 int exclude_portid = 0; 2512 2513 if (report) { 2514 refcount_inc(&skb->users); 2515 exclude_portid = portid; 2516 } 2517 2518 /* errors reported via destination sk->sk_err, but propagate 2519 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */ 2520 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags); 2521 } 2522 2523 if (report) { 2524 int err2; 2525 2526 err2 = nlmsg_unicast(sk, skb, portid); 2527 if (!err || err == -ESRCH) 2528 err = err2; 2529 } 2530 2531 return err; 2532 } 2533 EXPORT_SYMBOL(nlmsg_notify); 2534 2535 #ifdef CONFIG_PROC_FS 2536 struct nl_seq_iter { 2537 struct seq_net_private p; 2538 struct rhashtable_iter hti; 2539 int link; 2540 }; 2541 2542 static int netlink_walk_start(struct nl_seq_iter *iter) 2543 { 2544 int err; 2545 2546 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti, 2547 GFP_KERNEL); 2548 if (err) { 2549 iter->link = MAX_LINKS; 2550 return err; 2551 } 2552 2553 rhashtable_walk_start(&iter->hti); 2554 2555 return 0; 2556 } 2557 2558 static void netlink_walk_stop(struct nl_seq_iter *iter) 2559 { 2560 rhashtable_walk_stop(&iter->hti); 2561 rhashtable_walk_exit(&iter->hti); 2562 } 2563 2564 static void *__netlink_seq_next(struct seq_file *seq) 2565 { 2566 struct nl_seq_iter *iter = seq->private; 2567 struct netlink_sock *nlk; 2568 2569 do { 2570 for (;;) { 2571 int err; 2572 2573 nlk = rhashtable_walk_next(&iter->hti); 2574 2575 if (IS_ERR(nlk)) { 2576 if (PTR_ERR(nlk) == -EAGAIN) 2577 continue; 2578 2579 return nlk; 2580 } 2581 2582 if (nlk) 2583 break; 2584 2585 netlink_walk_stop(iter); 2586 if (++iter->link >= MAX_LINKS) 2587 return NULL; 2588 2589 err = netlink_walk_start(iter); 2590 if (err) 2591 return ERR_PTR(err); 2592 } 2593 } while (sock_net(&nlk->sk) != seq_file_net(seq)); 2594 2595 return nlk; 2596 } 2597 2598 static void *netlink_seq_start(struct seq_file *seq, loff_t *posp) 2599 { 2600 struct nl_seq_iter *iter = seq->private; 2601 void *obj = SEQ_START_TOKEN; 2602 loff_t pos; 2603 int err; 2604 2605 iter->link = 0; 2606 2607 err = netlink_walk_start(iter); 2608 if (err) 2609 return ERR_PTR(err); 2610 2611 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--) 2612 obj = __netlink_seq_next(seq); 2613 2614 return obj; 2615 } 2616 2617 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2618 { 2619 ++*pos; 2620 return __netlink_seq_next(seq); 2621 } 2622 2623 static void netlink_seq_stop(struct seq_file *seq, void *v) 2624 { 2625 struct nl_seq_iter *iter = seq->private; 2626 2627 if (iter->link >= MAX_LINKS) 2628 return; 2629 2630 netlink_walk_stop(iter); 2631 } 2632 2633 2634 static int netlink_seq_show(struct seq_file *seq, void *v) 2635 { 2636 if (v == SEQ_START_TOKEN) { 2637 seq_puts(seq, 2638 "sk Eth Pid Groups " 2639 "Rmem Wmem Dump Locks Drops Inode\n"); 2640 } else { 2641 struct sock *s = v; 2642 struct netlink_sock *nlk = nlk_sk(s); 2643 2644 seq_printf(seq, "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8d %-8lu\n", 2645 s, 2646 s->sk_protocol, 2647 nlk->portid, 2648 nlk->groups ? (u32)nlk->groups[0] : 0, 2649 sk_rmem_alloc_get(s), 2650 sk_wmem_alloc_get(s), 2651 nlk->cb_running, 2652 refcount_read(&s->sk_refcnt), 2653 atomic_read(&s->sk_drops), 2654 sock_i_ino(s) 2655 ); 2656 2657 } 2658 return 0; 2659 } 2660 2661 static const struct seq_operations netlink_seq_ops = { 2662 .start = netlink_seq_start, 2663 .next = netlink_seq_next, 2664 .stop = netlink_seq_stop, 2665 .show = netlink_seq_show, 2666 }; 2667 #endif 2668 2669 int netlink_register_notifier(struct notifier_block *nb) 2670 { 2671 return blocking_notifier_chain_register(&netlink_chain, nb); 2672 } 2673 EXPORT_SYMBOL(netlink_register_notifier); 2674 2675 int netlink_unregister_notifier(struct notifier_block *nb) 2676 { 2677 return blocking_notifier_chain_unregister(&netlink_chain, nb); 2678 } 2679 EXPORT_SYMBOL(netlink_unregister_notifier); 2680 2681 static const struct proto_ops netlink_ops = { 2682 .family = PF_NETLINK, 2683 .owner = THIS_MODULE, 2684 .release = netlink_release, 2685 .bind = netlink_bind, 2686 .connect = netlink_connect, 2687 .socketpair = sock_no_socketpair, 2688 .accept = sock_no_accept, 2689 .getname = netlink_getname, 2690 .poll = datagram_poll, 2691 .ioctl = netlink_ioctl, 2692 .listen = sock_no_listen, 2693 .shutdown = sock_no_shutdown, 2694 .setsockopt = netlink_setsockopt, 2695 .getsockopt = netlink_getsockopt, 2696 .sendmsg = netlink_sendmsg, 2697 .recvmsg = netlink_recvmsg, 2698 .mmap = sock_no_mmap, 2699 .sendpage = sock_no_sendpage, 2700 }; 2701 2702 static const struct net_proto_family netlink_family_ops = { 2703 .family = PF_NETLINK, 2704 .create = netlink_create, 2705 .owner = THIS_MODULE, /* for consistency 8) */ 2706 }; 2707 2708 static int __net_init netlink_net_init(struct net *net) 2709 { 2710 #ifdef CONFIG_PROC_FS 2711 if (!proc_create_net("netlink", 0, net->proc_net, &netlink_seq_ops, 2712 sizeof(struct nl_seq_iter))) 2713 return -ENOMEM; 2714 #endif 2715 return 0; 2716 } 2717 2718 static void __net_exit netlink_net_exit(struct net *net) 2719 { 2720 #ifdef CONFIG_PROC_FS 2721 remove_proc_entry("netlink", net->proc_net); 2722 #endif 2723 } 2724 2725 static void __init netlink_add_usersock_entry(void) 2726 { 2727 struct listeners *listeners; 2728 int groups = 32; 2729 2730 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2731 if (!listeners) 2732 panic("netlink_add_usersock_entry: Cannot allocate listeners\n"); 2733 2734 netlink_table_grab(); 2735 2736 nl_table[NETLINK_USERSOCK].groups = groups; 2737 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners); 2738 nl_table[NETLINK_USERSOCK].module = THIS_MODULE; 2739 nl_table[NETLINK_USERSOCK].registered = 1; 2740 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND; 2741 2742 netlink_table_ungrab(); 2743 } 2744 2745 static struct pernet_operations __net_initdata netlink_net_ops = { 2746 .init = netlink_net_init, 2747 .exit = netlink_net_exit, 2748 }; 2749 2750 static inline u32 netlink_hash(const void *data, u32 len, u32 seed) 2751 { 2752 const struct netlink_sock *nlk = data; 2753 struct netlink_compare_arg arg; 2754 2755 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid); 2756 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed); 2757 } 2758 2759 static const struct rhashtable_params netlink_rhashtable_params = { 2760 .head_offset = offsetof(struct netlink_sock, node), 2761 .key_len = netlink_compare_arg_len, 2762 .obj_hashfn = netlink_hash, 2763 .obj_cmpfn = netlink_compare, 2764 .automatic_shrinking = true, 2765 }; 2766 2767 static int __init netlink_proto_init(void) 2768 { 2769 int i; 2770 int err = proto_register(&netlink_proto, 0); 2771 2772 if (err != 0) 2773 goto out; 2774 2775 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb)); 2776 2777 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); 2778 if (!nl_table) 2779 goto panic; 2780 2781 for (i = 0; i < MAX_LINKS; i++) { 2782 if (rhashtable_init(&nl_table[i].hash, 2783 &netlink_rhashtable_params) < 0) { 2784 while (--i > 0) 2785 rhashtable_destroy(&nl_table[i].hash); 2786 kfree(nl_table); 2787 goto panic; 2788 } 2789 } 2790 2791 netlink_add_usersock_entry(); 2792 2793 sock_register(&netlink_family_ops); 2794 register_pernet_subsys(&netlink_net_ops); 2795 register_pernet_subsys(&netlink_tap_net_ops); 2796 /* The netlink device handler may be needed early. */ 2797 rtnetlink_init(); 2798 out: 2799 return err; 2800 panic: 2801 panic("netlink_init: Cannot allocate nl_table\n"); 2802 } 2803 2804 core_initcall(netlink_proto_init); 2805