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 67 #include <net/net_namespace.h> 68 #include <net/netns/generic.h> 69 #include <net/sock.h> 70 #include <net/scm.h> 71 #include <net/netlink.h> 72 73 #include "af_netlink.h" 74 75 struct listeners { 76 struct rcu_head rcu; 77 unsigned long masks[0]; 78 }; 79 80 /* state bits */ 81 #define NETLINK_S_CONGESTED 0x0 82 83 static inline int netlink_is_kernel(struct sock *sk) 84 { 85 return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET; 86 } 87 88 struct netlink_table *nl_table __read_mostly; 89 EXPORT_SYMBOL_GPL(nl_table); 90 91 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); 92 93 static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS]; 94 95 static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = { 96 "nlk_cb_mutex-ROUTE", 97 "nlk_cb_mutex-1", 98 "nlk_cb_mutex-USERSOCK", 99 "nlk_cb_mutex-FIREWALL", 100 "nlk_cb_mutex-SOCK_DIAG", 101 "nlk_cb_mutex-NFLOG", 102 "nlk_cb_mutex-XFRM", 103 "nlk_cb_mutex-SELINUX", 104 "nlk_cb_mutex-ISCSI", 105 "nlk_cb_mutex-AUDIT", 106 "nlk_cb_mutex-FIB_LOOKUP", 107 "nlk_cb_mutex-CONNECTOR", 108 "nlk_cb_mutex-NETFILTER", 109 "nlk_cb_mutex-IP6_FW", 110 "nlk_cb_mutex-DNRTMSG", 111 "nlk_cb_mutex-KOBJECT_UEVENT", 112 "nlk_cb_mutex-GENERIC", 113 "nlk_cb_mutex-17", 114 "nlk_cb_mutex-SCSITRANSPORT", 115 "nlk_cb_mutex-ECRYPTFS", 116 "nlk_cb_mutex-RDMA", 117 "nlk_cb_mutex-CRYPTO", 118 "nlk_cb_mutex-SMC", 119 "nlk_cb_mutex-23", 120 "nlk_cb_mutex-24", 121 "nlk_cb_mutex-25", 122 "nlk_cb_mutex-26", 123 "nlk_cb_mutex-27", 124 "nlk_cb_mutex-28", 125 "nlk_cb_mutex-29", 126 "nlk_cb_mutex-30", 127 "nlk_cb_mutex-31", 128 "nlk_cb_mutex-MAX_LINKS" 129 }; 130 131 static int netlink_dump(struct sock *sk); 132 133 /* nl_table locking explained: 134 * Lookup and traversal are protected with an RCU read-side lock. Insertion 135 * and removal are protected with per bucket lock while using RCU list 136 * modification primitives and may run in parallel to RCU protected lookups. 137 * Destruction of the Netlink socket may only occur *after* nl_table_lock has 138 * been acquired * either during or after the socket has been removed from 139 * the list and after an RCU grace period. 140 */ 141 DEFINE_RWLOCK(nl_table_lock); 142 EXPORT_SYMBOL_GPL(nl_table_lock); 143 static atomic_t nl_table_users = ATOMIC_INIT(0); 144 145 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock)); 146 147 static BLOCKING_NOTIFIER_HEAD(netlink_chain); 148 149 150 static const struct rhashtable_params netlink_rhashtable_params; 151 152 static inline u32 netlink_group_mask(u32 group) 153 { 154 return group ? 1 << (group - 1) : 0; 155 } 156 157 static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb, 158 gfp_t gfp_mask) 159 { 160 unsigned int len = skb_end_offset(skb); 161 struct sk_buff *new; 162 163 new = alloc_skb(len, gfp_mask); 164 if (new == NULL) 165 return NULL; 166 167 NETLINK_CB(new).portid = NETLINK_CB(skb).portid; 168 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group; 169 NETLINK_CB(new).creds = NETLINK_CB(skb).creds; 170 171 skb_put_data(new, skb->data, len); 172 return new; 173 } 174 175 static unsigned int netlink_tap_net_id; 176 177 struct netlink_tap_net { 178 struct list_head netlink_tap_all; 179 struct mutex netlink_tap_lock; 180 }; 181 182 int netlink_add_tap(struct netlink_tap *nt) 183 { 184 struct net *net = dev_net(nt->dev); 185 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 186 187 if (unlikely(nt->dev->type != ARPHRD_NETLINK)) 188 return -EINVAL; 189 190 mutex_lock(&nn->netlink_tap_lock); 191 list_add_rcu(&nt->list, &nn->netlink_tap_all); 192 mutex_unlock(&nn->netlink_tap_lock); 193 194 __module_get(nt->module); 195 196 return 0; 197 } 198 EXPORT_SYMBOL_GPL(netlink_add_tap); 199 200 static int __netlink_remove_tap(struct netlink_tap *nt) 201 { 202 struct net *net = dev_net(nt->dev); 203 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 204 bool found = false; 205 struct netlink_tap *tmp; 206 207 mutex_lock(&nn->netlink_tap_lock); 208 209 list_for_each_entry(tmp, &nn->netlink_tap_all, list) { 210 if (nt == tmp) { 211 list_del_rcu(&nt->list); 212 found = true; 213 goto out; 214 } 215 } 216 217 pr_warn("__netlink_remove_tap: %p not found\n", nt); 218 out: 219 mutex_unlock(&nn->netlink_tap_lock); 220 221 if (found) 222 module_put(nt->module); 223 224 return found ? 0 : -ENODEV; 225 } 226 227 int netlink_remove_tap(struct netlink_tap *nt) 228 { 229 int ret; 230 231 ret = __netlink_remove_tap(nt); 232 synchronize_net(); 233 234 return ret; 235 } 236 EXPORT_SYMBOL_GPL(netlink_remove_tap); 237 238 static __net_init int netlink_tap_init_net(struct net *net) 239 { 240 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 241 242 INIT_LIST_HEAD(&nn->netlink_tap_all); 243 mutex_init(&nn->netlink_tap_lock); 244 return 0; 245 } 246 247 static void __net_exit netlink_tap_exit_net(struct net *net) 248 { 249 } 250 251 static struct pernet_operations netlink_tap_net_ops = { 252 .init = netlink_tap_init_net, 253 .exit = netlink_tap_exit_net, 254 .id = &netlink_tap_net_id, 255 .size = sizeof(struct netlink_tap_net), 256 }; 257 258 static bool netlink_filter_tap(const struct sk_buff *skb) 259 { 260 struct sock *sk = skb->sk; 261 262 /* We take the more conservative approach and 263 * whitelist socket protocols that may pass. 264 */ 265 switch (sk->sk_protocol) { 266 case NETLINK_ROUTE: 267 case NETLINK_USERSOCK: 268 case NETLINK_SOCK_DIAG: 269 case NETLINK_NFLOG: 270 case NETLINK_XFRM: 271 case NETLINK_FIB_LOOKUP: 272 case NETLINK_NETFILTER: 273 case NETLINK_GENERIC: 274 return true; 275 } 276 277 return false; 278 } 279 280 static int __netlink_deliver_tap_skb(struct sk_buff *skb, 281 struct net_device *dev) 282 { 283 struct sk_buff *nskb; 284 struct sock *sk = skb->sk; 285 int ret = -ENOMEM; 286 287 if (!net_eq(dev_net(dev), sock_net(sk))) 288 return 0; 289 290 dev_hold(dev); 291 292 if (is_vmalloc_addr(skb->head)) 293 nskb = netlink_to_full_skb(skb, GFP_ATOMIC); 294 else 295 nskb = skb_clone(skb, GFP_ATOMIC); 296 if (nskb) { 297 nskb->dev = dev; 298 nskb->protocol = htons((u16) sk->sk_protocol); 299 nskb->pkt_type = netlink_is_kernel(sk) ? 300 PACKET_KERNEL : PACKET_USER; 301 skb_reset_network_header(nskb); 302 ret = dev_queue_xmit(nskb); 303 if (unlikely(ret > 0)) 304 ret = net_xmit_errno(ret); 305 } 306 307 dev_put(dev); 308 return ret; 309 } 310 311 static void __netlink_deliver_tap(struct sk_buff *skb, struct netlink_tap_net *nn) 312 { 313 int ret; 314 struct netlink_tap *tmp; 315 316 if (!netlink_filter_tap(skb)) 317 return; 318 319 list_for_each_entry_rcu(tmp, &nn->netlink_tap_all, list) { 320 ret = __netlink_deliver_tap_skb(skb, tmp->dev); 321 if (unlikely(ret)) 322 break; 323 } 324 } 325 326 static void netlink_deliver_tap(struct net *net, struct sk_buff *skb) 327 { 328 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 329 330 rcu_read_lock(); 331 332 if (unlikely(!list_empty(&nn->netlink_tap_all))) 333 __netlink_deliver_tap(skb, nn); 334 335 rcu_read_unlock(); 336 } 337 338 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src, 339 struct sk_buff *skb) 340 { 341 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src))) 342 netlink_deliver_tap(sock_net(dst), skb); 343 } 344 345 static void netlink_overrun(struct sock *sk) 346 { 347 struct netlink_sock *nlk = nlk_sk(sk); 348 349 if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) { 350 if (!test_and_set_bit(NETLINK_S_CONGESTED, 351 &nlk_sk(sk)->state)) { 352 sk->sk_err = ENOBUFS; 353 sk->sk_error_report(sk); 354 } 355 } 356 atomic_inc(&sk->sk_drops); 357 } 358 359 static void netlink_rcv_wake(struct sock *sk) 360 { 361 struct netlink_sock *nlk = nlk_sk(sk); 362 363 if (skb_queue_empty(&sk->sk_receive_queue)) 364 clear_bit(NETLINK_S_CONGESTED, &nlk->state); 365 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state)) 366 wake_up_interruptible(&nlk->wait); 367 } 368 369 static void netlink_skb_destructor(struct sk_buff *skb) 370 { 371 if (is_vmalloc_addr(skb->head)) { 372 if (!skb->cloned || 373 !atomic_dec_return(&(skb_shinfo(skb)->dataref))) 374 vfree(skb->head); 375 376 skb->head = NULL; 377 } 378 if (skb->sk != NULL) 379 sock_rfree(skb); 380 } 381 382 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk) 383 { 384 WARN_ON(skb->sk != NULL); 385 skb->sk = sk; 386 skb->destructor = netlink_skb_destructor; 387 atomic_add(skb->truesize, &sk->sk_rmem_alloc); 388 sk_mem_charge(sk, skb->truesize); 389 } 390 391 static void netlink_sock_destruct(struct sock *sk) 392 { 393 struct netlink_sock *nlk = nlk_sk(sk); 394 395 if (nlk->cb_running) { 396 if (nlk->cb.done) 397 nlk->cb.done(&nlk->cb); 398 module_put(nlk->cb.module); 399 kfree_skb(nlk->cb.skb); 400 } 401 402 skb_queue_purge(&sk->sk_receive_queue); 403 404 if (!sock_flag(sk, SOCK_DEAD)) { 405 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk); 406 return; 407 } 408 409 WARN_ON(atomic_read(&sk->sk_rmem_alloc)); 410 WARN_ON(refcount_read(&sk->sk_wmem_alloc)); 411 WARN_ON(nlk_sk(sk)->groups); 412 } 413 414 static void netlink_sock_destruct_work(struct work_struct *work) 415 { 416 struct netlink_sock *nlk = container_of(work, struct netlink_sock, 417 work); 418 419 sk_free(&nlk->sk); 420 } 421 422 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on 423 * SMP. Look, when several writers sleep and reader wakes them up, all but one 424 * immediately hit write lock and grab all the cpus. Exclusive sleep solves 425 * this, _but_ remember, it adds useless work on UP machines. 426 */ 427 428 void netlink_table_grab(void) 429 __acquires(nl_table_lock) 430 { 431 might_sleep(); 432 433 write_lock_irq(&nl_table_lock); 434 435 if (atomic_read(&nl_table_users)) { 436 DECLARE_WAITQUEUE(wait, current); 437 438 add_wait_queue_exclusive(&nl_table_wait, &wait); 439 for (;;) { 440 set_current_state(TASK_UNINTERRUPTIBLE); 441 if (atomic_read(&nl_table_users) == 0) 442 break; 443 write_unlock_irq(&nl_table_lock); 444 schedule(); 445 write_lock_irq(&nl_table_lock); 446 } 447 448 __set_current_state(TASK_RUNNING); 449 remove_wait_queue(&nl_table_wait, &wait); 450 } 451 } 452 453 void netlink_table_ungrab(void) 454 __releases(nl_table_lock) 455 { 456 write_unlock_irq(&nl_table_lock); 457 wake_up(&nl_table_wait); 458 } 459 460 static inline void 461 netlink_lock_table(void) 462 { 463 /* read_lock() synchronizes us to netlink_table_grab */ 464 465 read_lock(&nl_table_lock); 466 atomic_inc(&nl_table_users); 467 read_unlock(&nl_table_lock); 468 } 469 470 static inline void 471 netlink_unlock_table(void) 472 { 473 if (atomic_dec_and_test(&nl_table_users)) 474 wake_up(&nl_table_wait); 475 } 476 477 struct netlink_compare_arg 478 { 479 possible_net_t pnet; 480 u32 portid; 481 }; 482 483 /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */ 484 #define netlink_compare_arg_len \ 485 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32)) 486 487 static inline int netlink_compare(struct rhashtable_compare_arg *arg, 488 const void *ptr) 489 { 490 const struct netlink_compare_arg *x = arg->key; 491 const struct netlink_sock *nlk = ptr; 492 493 return nlk->portid != x->portid || 494 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet)); 495 } 496 497 static void netlink_compare_arg_init(struct netlink_compare_arg *arg, 498 struct net *net, u32 portid) 499 { 500 memset(arg, 0, sizeof(*arg)); 501 write_pnet(&arg->pnet, net); 502 arg->portid = portid; 503 } 504 505 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid, 506 struct net *net) 507 { 508 struct netlink_compare_arg arg; 509 510 netlink_compare_arg_init(&arg, net, portid); 511 return rhashtable_lookup_fast(&table->hash, &arg, 512 netlink_rhashtable_params); 513 } 514 515 static int __netlink_insert(struct netlink_table *table, struct sock *sk) 516 { 517 struct netlink_compare_arg arg; 518 519 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid); 520 return rhashtable_lookup_insert_key(&table->hash, &arg, 521 &nlk_sk(sk)->node, 522 netlink_rhashtable_params); 523 } 524 525 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid) 526 { 527 struct netlink_table *table = &nl_table[protocol]; 528 struct sock *sk; 529 530 rcu_read_lock(); 531 sk = __netlink_lookup(table, portid, net); 532 if (sk) 533 sock_hold(sk); 534 rcu_read_unlock(); 535 536 return sk; 537 } 538 539 static const struct proto_ops netlink_ops; 540 541 static void 542 netlink_update_listeners(struct sock *sk) 543 { 544 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 545 unsigned long mask; 546 unsigned int i; 547 struct listeners *listeners; 548 549 listeners = nl_deref_protected(tbl->listeners); 550 if (!listeners) 551 return; 552 553 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) { 554 mask = 0; 555 sk_for_each_bound(sk, &tbl->mc_list) { 556 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups)) 557 mask |= nlk_sk(sk)->groups[i]; 558 } 559 listeners->masks[i] = mask; 560 } 561 /* this function is only called with the netlink table "grabbed", which 562 * makes sure updates are visible before bind or setsockopt return. */ 563 } 564 565 static int netlink_insert(struct sock *sk, u32 portid) 566 { 567 struct netlink_table *table = &nl_table[sk->sk_protocol]; 568 int err; 569 570 lock_sock(sk); 571 572 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY; 573 if (nlk_sk(sk)->bound) 574 goto err; 575 576 err = -ENOMEM; 577 if (BITS_PER_LONG > 32 && 578 unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX)) 579 goto err; 580 581 nlk_sk(sk)->portid = portid; 582 sock_hold(sk); 583 584 err = __netlink_insert(table, sk); 585 if (err) { 586 /* In case the hashtable backend returns with -EBUSY 587 * from here, it must not escape to the caller. 588 */ 589 if (unlikely(err == -EBUSY)) 590 err = -EOVERFLOW; 591 if (err == -EEXIST) 592 err = -EADDRINUSE; 593 sock_put(sk); 594 goto err; 595 } 596 597 /* We need to ensure that the socket is hashed and visible. */ 598 smp_wmb(); 599 nlk_sk(sk)->bound = portid; 600 601 err: 602 release_sock(sk); 603 return err; 604 } 605 606 static void netlink_remove(struct sock *sk) 607 { 608 struct netlink_table *table; 609 610 table = &nl_table[sk->sk_protocol]; 611 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node, 612 netlink_rhashtable_params)) { 613 WARN_ON(refcount_read(&sk->sk_refcnt) == 1); 614 __sock_put(sk); 615 } 616 617 netlink_table_grab(); 618 if (nlk_sk(sk)->subscriptions) { 619 __sk_del_bind_node(sk); 620 netlink_update_listeners(sk); 621 } 622 if (sk->sk_protocol == NETLINK_GENERIC) 623 atomic_inc(&genl_sk_destructing_cnt); 624 netlink_table_ungrab(); 625 } 626 627 static struct proto netlink_proto = { 628 .name = "NETLINK", 629 .owner = THIS_MODULE, 630 .obj_size = sizeof(struct netlink_sock), 631 }; 632 633 static int __netlink_create(struct net *net, struct socket *sock, 634 struct mutex *cb_mutex, int protocol, 635 int kern) 636 { 637 struct sock *sk; 638 struct netlink_sock *nlk; 639 640 sock->ops = &netlink_ops; 641 642 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern); 643 if (!sk) 644 return -ENOMEM; 645 646 sock_init_data(sock, sk); 647 648 nlk = nlk_sk(sk); 649 if (cb_mutex) { 650 nlk->cb_mutex = cb_mutex; 651 } else { 652 nlk->cb_mutex = &nlk->cb_def_mutex; 653 mutex_init(nlk->cb_mutex); 654 lockdep_set_class_and_name(nlk->cb_mutex, 655 nlk_cb_mutex_keys + protocol, 656 nlk_cb_mutex_key_strings[protocol]); 657 } 658 init_waitqueue_head(&nlk->wait); 659 660 sk->sk_destruct = netlink_sock_destruct; 661 sk->sk_protocol = protocol; 662 return 0; 663 } 664 665 static int netlink_create(struct net *net, struct socket *sock, int protocol, 666 int kern) 667 { 668 struct module *module = NULL; 669 struct mutex *cb_mutex; 670 struct netlink_sock *nlk; 671 int (*bind)(struct net *net, int group); 672 void (*unbind)(struct net *net, int group); 673 int err = 0; 674 675 sock->state = SS_UNCONNECTED; 676 677 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) 678 return -ESOCKTNOSUPPORT; 679 680 if (protocol < 0 || protocol >= MAX_LINKS) 681 return -EPROTONOSUPPORT; 682 683 netlink_lock_table(); 684 #ifdef CONFIG_MODULES 685 if (!nl_table[protocol].registered) { 686 netlink_unlock_table(); 687 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); 688 netlink_lock_table(); 689 } 690 #endif 691 if (nl_table[protocol].registered && 692 try_module_get(nl_table[protocol].module)) 693 module = nl_table[protocol].module; 694 else 695 err = -EPROTONOSUPPORT; 696 cb_mutex = nl_table[protocol].cb_mutex; 697 bind = nl_table[protocol].bind; 698 unbind = nl_table[protocol].unbind; 699 netlink_unlock_table(); 700 701 if (err < 0) 702 goto out; 703 704 err = __netlink_create(net, sock, cb_mutex, protocol, kern); 705 if (err < 0) 706 goto out_module; 707 708 local_bh_disable(); 709 sock_prot_inuse_add(net, &netlink_proto, 1); 710 local_bh_enable(); 711 712 nlk = nlk_sk(sock->sk); 713 nlk->module = module; 714 nlk->netlink_bind = bind; 715 nlk->netlink_unbind = unbind; 716 out: 717 return err; 718 719 out_module: 720 module_put(module); 721 goto out; 722 } 723 724 static void deferred_put_nlk_sk(struct rcu_head *head) 725 { 726 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu); 727 struct sock *sk = &nlk->sk; 728 729 kfree(nlk->groups); 730 nlk->groups = NULL; 731 732 if (!refcount_dec_and_test(&sk->sk_refcnt)) 733 return; 734 735 if (nlk->cb_running && nlk->cb.done) { 736 INIT_WORK(&nlk->work, netlink_sock_destruct_work); 737 schedule_work(&nlk->work); 738 return; 739 } 740 741 sk_free(sk); 742 } 743 744 static int netlink_release(struct socket *sock) 745 { 746 struct sock *sk = sock->sk; 747 struct netlink_sock *nlk; 748 749 if (!sk) 750 return 0; 751 752 netlink_remove(sk); 753 sock_orphan(sk); 754 nlk = nlk_sk(sk); 755 756 /* 757 * OK. Socket is unlinked, any packets that arrive now 758 * will be purged. 759 */ 760 761 /* must not acquire netlink_table_lock in any way again before unbind 762 * and notifying genetlink is done as otherwise it might deadlock 763 */ 764 if (nlk->netlink_unbind) { 765 int i; 766 767 for (i = 0; i < nlk->ngroups; i++) 768 if (test_bit(i, nlk->groups)) 769 nlk->netlink_unbind(sock_net(sk), i + 1); 770 } 771 if (sk->sk_protocol == NETLINK_GENERIC && 772 atomic_dec_return(&genl_sk_destructing_cnt) == 0) 773 wake_up(&genl_sk_destructing_waitq); 774 775 sock->sk = NULL; 776 wake_up_interruptible_all(&nlk->wait); 777 778 skb_queue_purge(&sk->sk_write_queue); 779 780 if (nlk->portid && nlk->bound) { 781 struct netlink_notify n = { 782 .net = sock_net(sk), 783 .protocol = sk->sk_protocol, 784 .portid = nlk->portid, 785 }; 786 blocking_notifier_call_chain(&netlink_chain, 787 NETLINK_URELEASE, &n); 788 } 789 790 module_put(nlk->module); 791 792 if (netlink_is_kernel(sk)) { 793 netlink_table_grab(); 794 BUG_ON(nl_table[sk->sk_protocol].registered == 0); 795 if (--nl_table[sk->sk_protocol].registered == 0) { 796 struct listeners *old; 797 798 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners); 799 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL); 800 kfree_rcu(old, rcu); 801 nl_table[sk->sk_protocol].module = NULL; 802 nl_table[sk->sk_protocol].bind = NULL; 803 nl_table[sk->sk_protocol].unbind = NULL; 804 nl_table[sk->sk_protocol].flags = 0; 805 nl_table[sk->sk_protocol].registered = 0; 806 } 807 netlink_table_ungrab(); 808 } 809 810 local_bh_disable(); 811 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1); 812 local_bh_enable(); 813 call_rcu(&nlk->rcu, deferred_put_nlk_sk); 814 return 0; 815 } 816 817 static int netlink_autobind(struct socket *sock) 818 { 819 struct sock *sk = sock->sk; 820 struct net *net = sock_net(sk); 821 struct netlink_table *table = &nl_table[sk->sk_protocol]; 822 s32 portid = task_tgid_vnr(current); 823 int err; 824 s32 rover = -4096; 825 bool ok; 826 827 retry: 828 cond_resched(); 829 rcu_read_lock(); 830 ok = !__netlink_lookup(table, portid, net); 831 rcu_read_unlock(); 832 if (!ok) { 833 /* Bind collision, search negative portid values. */ 834 if (rover == -4096) 835 /* rover will be in range [S32_MIN, -4097] */ 836 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN); 837 else if (rover >= -4096) 838 rover = -4097; 839 portid = rover--; 840 goto retry; 841 } 842 843 err = netlink_insert(sk, portid); 844 if (err == -EADDRINUSE) 845 goto retry; 846 847 /* If 2 threads race to autobind, that is fine. */ 848 if (err == -EBUSY) 849 err = 0; 850 851 return err; 852 } 853 854 /** 855 * __netlink_ns_capable - General netlink message capability test 856 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace. 857 * @user_ns: The user namespace of the capability to use 858 * @cap: The capability to use 859 * 860 * Test to see if the opener of the socket we received the message 861 * from had when the netlink socket was created and the sender of the 862 * message has has the capability @cap in the user namespace @user_ns. 863 */ 864 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp, 865 struct user_namespace *user_ns, int cap) 866 { 867 return ((nsp->flags & NETLINK_SKB_DST) || 868 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) && 869 ns_capable(user_ns, cap); 870 } 871 EXPORT_SYMBOL(__netlink_ns_capable); 872 873 /** 874 * netlink_ns_capable - General netlink message capability test 875 * @skb: socket buffer holding a netlink command from userspace 876 * @user_ns: The user namespace of the capability to use 877 * @cap: The capability to use 878 * 879 * Test to see if the opener of the socket we received the message 880 * from had when the netlink socket was created and the sender of the 881 * message has has the capability @cap in the user namespace @user_ns. 882 */ 883 bool netlink_ns_capable(const struct sk_buff *skb, 884 struct user_namespace *user_ns, int cap) 885 { 886 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap); 887 } 888 EXPORT_SYMBOL(netlink_ns_capable); 889 890 /** 891 * netlink_capable - Netlink global message capability test 892 * @skb: socket buffer holding a netlink command from userspace 893 * @cap: The capability to use 894 * 895 * Test to see if the opener of the socket we received the message 896 * from had when the netlink socket was created and the sender of the 897 * message has has the capability @cap in all user namespaces. 898 */ 899 bool netlink_capable(const struct sk_buff *skb, int cap) 900 { 901 return netlink_ns_capable(skb, &init_user_ns, cap); 902 } 903 EXPORT_SYMBOL(netlink_capable); 904 905 /** 906 * netlink_net_capable - Netlink network namespace message capability test 907 * @skb: socket buffer holding a netlink command from userspace 908 * @cap: The capability to use 909 * 910 * Test to see if the opener of the socket we received the message 911 * from had when the netlink socket was created and the sender of the 912 * message has has the capability @cap over the network namespace of 913 * the socket we received the message from. 914 */ 915 bool netlink_net_capable(const struct sk_buff *skb, int cap) 916 { 917 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap); 918 } 919 EXPORT_SYMBOL(netlink_net_capable); 920 921 static inline int netlink_allowed(const struct socket *sock, unsigned int flag) 922 { 923 return (nl_table[sock->sk->sk_protocol].flags & flag) || 924 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN); 925 } 926 927 static void 928 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) 929 { 930 struct netlink_sock *nlk = nlk_sk(sk); 931 932 if (nlk->subscriptions && !subscriptions) 933 __sk_del_bind_node(sk); 934 else if (!nlk->subscriptions && subscriptions) 935 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); 936 nlk->subscriptions = subscriptions; 937 } 938 939 static int netlink_realloc_groups(struct sock *sk) 940 { 941 struct netlink_sock *nlk = nlk_sk(sk); 942 unsigned int groups; 943 unsigned long *new_groups; 944 int err = 0; 945 946 netlink_table_grab(); 947 948 groups = nl_table[sk->sk_protocol].groups; 949 if (!nl_table[sk->sk_protocol].registered) { 950 err = -ENOENT; 951 goto out_unlock; 952 } 953 954 if (nlk->ngroups >= groups) 955 goto out_unlock; 956 957 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC); 958 if (new_groups == NULL) { 959 err = -ENOMEM; 960 goto out_unlock; 961 } 962 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0, 963 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups)); 964 965 nlk->groups = new_groups; 966 nlk->ngroups = groups; 967 out_unlock: 968 netlink_table_ungrab(); 969 return err; 970 } 971 972 static void netlink_undo_bind(int group, long unsigned int groups, 973 struct sock *sk) 974 { 975 struct netlink_sock *nlk = nlk_sk(sk); 976 int undo; 977 978 if (!nlk->netlink_unbind) 979 return; 980 981 for (undo = 0; undo < group; undo++) 982 if (test_bit(undo, &groups)) 983 nlk->netlink_unbind(sock_net(sk), undo + 1); 984 } 985 986 static int netlink_bind(struct socket *sock, struct sockaddr *addr, 987 int addr_len) 988 { 989 struct sock *sk = sock->sk; 990 struct net *net = sock_net(sk); 991 struct netlink_sock *nlk = nlk_sk(sk); 992 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 993 int err = 0; 994 long unsigned int groups = nladdr->nl_groups; 995 bool bound; 996 997 if (addr_len < sizeof(struct sockaddr_nl)) 998 return -EINVAL; 999 1000 if (nladdr->nl_family != AF_NETLINK) 1001 return -EINVAL; 1002 1003 /* Only superuser is allowed to listen multicasts */ 1004 if (groups) { 1005 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) 1006 return -EPERM; 1007 err = netlink_realloc_groups(sk); 1008 if (err) 1009 return err; 1010 } 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 default: 1710 err = -ENOPROTOOPT; 1711 } 1712 return err; 1713 } 1714 1715 static int netlink_getsockopt(struct socket *sock, int level, int optname, 1716 char __user *optval, int __user *optlen) 1717 { 1718 struct sock *sk = sock->sk; 1719 struct netlink_sock *nlk = nlk_sk(sk); 1720 int len, val, err; 1721 1722 if (level != SOL_NETLINK) 1723 return -ENOPROTOOPT; 1724 1725 if (get_user(len, optlen)) 1726 return -EFAULT; 1727 if (len < 0) 1728 return -EINVAL; 1729 1730 switch (optname) { 1731 case NETLINK_PKTINFO: 1732 if (len < sizeof(int)) 1733 return -EINVAL; 1734 len = sizeof(int); 1735 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0; 1736 if (put_user(len, optlen) || 1737 put_user(val, optval)) 1738 return -EFAULT; 1739 err = 0; 1740 break; 1741 case NETLINK_BROADCAST_ERROR: 1742 if (len < sizeof(int)) 1743 return -EINVAL; 1744 len = sizeof(int); 1745 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0; 1746 if (put_user(len, optlen) || 1747 put_user(val, optval)) 1748 return -EFAULT; 1749 err = 0; 1750 break; 1751 case NETLINK_NO_ENOBUFS: 1752 if (len < sizeof(int)) 1753 return -EINVAL; 1754 len = sizeof(int); 1755 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0; 1756 if (put_user(len, optlen) || 1757 put_user(val, optval)) 1758 return -EFAULT; 1759 err = 0; 1760 break; 1761 case NETLINK_LIST_MEMBERSHIPS: { 1762 int pos, idx, shift; 1763 1764 err = 0; 1765 netlink_lock_table(); 1766 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) { 1767 if (len - pos < sizeof(u32)) 1768 break; 1769 1770 idx = pos / sizeof(unsigned long); 1771 shift = (pos % sizeof(unsigned long)) * 8; 1772 if (put_user((u32)(nlk->groups[idx] >> shift), 1773 (u32 __user *)(optval + pos))) { 1774 err = -EFAULT; 1775 break; 1776 } 1777 } 1778 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen)) 1779 err = -EFAULT; 1780 netlink_unlock_table(); 1781 break; 1782 } 1783 case NETLINK_CAP_ACK: 1784 if (len < sizeof(int)) 1785 return -EINVAL; 1786 len = sizeof(int); 1787 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0; 1788 if (put_user(len, optlen) || 1789 put_user(val, optval)) 1790 return -EFAULT; 1791 err = 0; 1792 break; 1793 case NETLINK_EXT_ACK: 1794 if (len < sizeof(int)) 1795 return -EINVAL; 1796 len = sizeof(int); 1797 val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0; 1798 if (put_user(len, optlen) || put_user(val, optval)) 1799 return -EFAULT; 1800 err = 0; 1801 break; 1802 default: 1803 err = -ENOPROTOOPT; 1804 } 1805 return err; 1806 } 1807 1808 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) 1809 { 1810 struct nl_pktinfo info; 1811 1812 info.group = NETLINK_CB(skb).dst_group; 1813 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); 1814 } 1815 1816 static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg, 1817 struct sk_buff *skb) 1818 { 1819 if (!NETLINK_CB(skb).nsid_is_set) 1820 return; 1821 1822 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int), 1823 &NETLINK_CB(skb).nsid); 1824 } 1825 1826 static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 1827 { 1828 struct sock *sk = sock->sk; 1829 struct netlink_sock *nlk = nlk_sk(sk); 1830 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); 1831 u32 dst_portid; 1832 u32 dst_group; 1833 struct sk_buff *skb; 1834 int err; 1835 struct scm_cookie scm; 1836 u32 netlink_skb_flags = 0; 1837 1838 if (msg->msg_flags&MSG_OOB) 1839 return -EOPNOTSUPP; 1840 1841 err = scm_send(sock, msg, &scm, true); 1842 if (err < 0) 1843 return err; 1844 1845 if (msg->msg_namelen) { 1846 err = -EINVAL; 1847 if (msg->msg_namelen < sizeof(struct sockaddr_nl)) 1848 goto out; 1849 if (addr->nl_family != AF_NETLINK) 1850 goto out; 1851 dst_portid = addr->nl_pid; 1852 dst_group = ffs(addr->nl_groups); 1853 err = -EPERM; 1854 if ((dst_group || dst_portid) && 1855 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) 1856 goto out; 1857 netlink_skb_flags |= NETLINK_SKB_DST; 1858 } else { 1859 dst_portid = nlk->dst_portid; 1860 dst_group = nlk->dst_group; 1861 } 1862 1863 if (!nlk->bound) { 1864 err = netlink_autobind(sock); 1865 if (err) 1866 goto out; 1867 } else { 1868 /* Ensure nlk is hashed and visible. */ 1869 smp_rmb(); 1870 } 1871 1872 err = -EMSGSIZE; 1873 if (len > sk->sk_sndbuf - 32) 1874 goto out; 1875 err = -ENOBUFS; 1876 skb = netlink_alloc_large_skb(len, dst_group); 1877 if (skb == NULL) 1878 goto out; 1879 1880 NETLINK_CB(skb).portid = nlk->portid; 1881 NETLINK_CB(skb).dst_group = dst_group; 1882 NETLINK_CB(skb).creds = scm.creds; 1883 NETLINK_CB(skb).flags = netlink_skb_flags; 1884 1885 err = -EFAULT; 1886 if (memcpy_from_msg(skb_put(skb, len), msg, len)) { 1887 kfree_skb(skb); 1888 goto out; 1889 } 1890 1891 err = security_netlink_send(sk, skb); 1892 if (err) { 1893 kfree_skb(skb); 1894 goto out; 1895 } 1896 1897 if (dst_group) { 1898 refcount_inc(&skb->users); 1899 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL); 1900 } 1901 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT); 1902 1903 out: 1904 scm_destroy(&scm); 1905 return err; 1906 } 1907 1908 static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 1909 int flags) 1910 { 1911 struct scm_cookie scm; 1912 struct sock *sk = sock->sk; 1913 struct netlink_sock *nlk = nlk_sk(sk); 1914 int noblock = flags&MSG_DONTWAIT; 1915 size_t copied; 1916 struct sk_buff *skb, *data_skb; 1917 int err, ret; 1918 1919 if (flags&MSG_OOB) 1920 return -EOPNOTSUPP; 1921 1922 copied = 0; 1923 1924 skb = skb_recv_datagram(sk, flags, noblock, &err); 1925 if (skb == NULL) 1926 goto out; 1927 1928 data_skb = skb; 1929 1930 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES 1931 if (unlikely(skb_shinfo(skb)->frag_list)) { 1932 /* 1933 * If this skb has a frag_list, then here that means that we 1934 * will have to use the frag_list skb's data for compat tasks 1935 * and the regular skb's data for normal (non-compat) tasks. 1936 * 1937 * If we need to send the compat skb, assign it to the 1938 * 'data_skb' variable so that it will be used below for data 1939 * copying. We keep 'skb' for everything else, including 1940 * freeing both later. 1941 */ 1942 if (flags & MSG_CMSG_COMPAT) 1943 data_skb = skb_shinfo(skb)->frag_list; 1944 } 1945 #endif 1946 1947 /* Record the max length of recvmsg() calls for future allocations */ 1948 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len); 1949 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len, 1950 SKB_WITH_OVERHEAD(32768)); 1951 1952 copied = data_skb->len; 1953 if (len < copied) { 1954 msg->msg_flags |= MSG_TRUNC; 1955 copied = len; 1956 } 1957 1958 skb_reset_transport_header(data_skb); 1959 err = skb_copy_datagram_msg(data_skb, 0, msg, copied); 1960 1961 if (msg->msg_name) { 1962 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); 1963 addr->nl_family = AF_NETLINK; 1964 addr->nl_pad = 0; 1965 addr->nl_pid = NETLINK_CB(skb).portid; 1966 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); 1967 msg->msg_namelen = sizeof(*addr); 1968 } 1969 1970 if (nlk->flags & NETLINK_F_RECV_PKTINFO) 1971 netlink_cmsg_recv_pktinfo(msg, skb); 1972 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID) 1973 netlink_cmsg_listen_all_nsid(sk, msg, skb); 1974 1975 memset(&scm, 0, sizeof(scm)); 1976 scm.creds = *NETLINK_CREDS(skb); 1977 if (flags & MSG_TRUNC) 1978 copied = data_skb->len; 1979 1980 skb_free_datagram(sk, skb); 1981 1982 if (nlk->cb_running && 1983 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { 1984 ret = netlink_dump(sk); 1985 if (ret) { 1986 sk->sk_err = -ret; 1987 sk->sk_error_report(sk); 1988 } 1989 } 1990 1991 scm_recv(sock, msg, &scm, flags); 1992 out: 1993 netlink_rcv_wake(sk); 1994 return err ? : copied; 1995 } 1996 1997 static void netlink_data_ready(struct sock *sk) 1998 { 1999 BUG(); 2000 } 2001 2002 /* 2003 * We export these functions to other modules. They provide a 2004 * complete set of kernel non-blocking support for message 2005 * queueing. 2006 */ 2007 2008 struct sock * 2009 __netlink_kernel_create(struct net *net, int unit, struct module *module, 2010 struct netlink_kernel_cfg *cfg) 2011 { 2012 struct socket *sock; 2013 struct sock *sk; 2014 struct netlink_sock *nlk; 2015 struct listeners *listeners = NULL; 2016 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL; 2017 unsigned int groups; 2018 2019 BUG_ON(!nl_table); 2020 2021 if (unit < 0 || unit >= MAX_LINKS) 2022 return NULL; 2023 2024 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) 2025 return NULL; 2026 2027 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0) 2028 goto out_sock_release_nosk; 2029 2030 sk = sock->sk; 2031 2032 if (!cfg || cfg->groups < 32) 2033 groups = 32; 2034 else 2035 groups = cfg->groups; 2036 2037 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2038 if (!listeners) 2039 goto out_sock_release; 2040 2041 sk->sk_data_ready = netlink_data_ready; 2042 if (cfg && cfg->input) 2043 nlk_sk(sk)->netlink_rcv = cfg->input; 2044 2045 if (netlink_insert(sk, 0)) 2046 goto out_sock_release; 2047 2048 nlk = nlk_sk(sk); 2049 nlk->flags |= NETLINK_F_KERNEL_SOCKET; 2050 2051 netlink_table_grab(); 2052 if (!nl_table[unit].registered) { 2053 nl_table[unit].groups = groups; 2054 rcu_assign_pointer(nl_table[unit].listeners, listeners); 2055 nl_table[unit].cb_mutex = cb_mutex; 2056 nl_table[unit].module = module; 2057 if (cfg) { 2058 nl_table[unit].bind = cfg->bind; 2059 nl_table[unit].unbind = cfg->unbind; 2060 nl_table[unit].flags = cfg->flags; 2061 if (cfg->compare) 2062 nl_table[unit].compare = cfg->compare; 2063 } 2064 nl_table[unit].registered = 1; 2065 } else { 2066 kfree(listeners); 2067 nl_table[unit].registered++; 2068 } 2069 netlink_table_ungrab(); 2070 return sk; 2071 2072 out_sock_release: 2073 kfree(listeners); 2074 netlink_kernel_release(sk); 2075 return NULL; 2076 2077 out_sock_release_nosk: 2078 sock_release(sock); 2079 return NULL; 2080 } 2081 EXPORT_SYMBOL(__netlink_kernel_create); 2082 2083 void 2084 netlink_kernel_release(struct sock *sk) 2085 { 2086 if (sk == NULL || sk->sk_socket == NULL) 2087 return; 2088 2089 sock_release(sk->sk_socket); 2090 } 2091 EXPORT_SYMBOL(netlink_kernel_release); 2092 2093 int __netlink_change_ngroups(struct sock *sk, unsigned int groups) 2094 { 2095 struct listeners *new, *old; 2096 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 2097 2098 if (groups < 32) 2099 groups = 32; 2100 2101 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) { 2102 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC); 2103 if (!new) 2104 return -ENOMEM; 2105 old = nl_deref_protected(tbl->listeners); 2106 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups)); 2107 rcu_assign_pointer(tbl->listeners, new); 2108 2109 kfree_rcu(old, rcu); 2110 } 2111 tbl->groups = groups; 2112 2113 return 0; 2114 } 2115 2116 /** 2117 * netlink_change_ngroups - change number of multicast groups 2118 * 2119 * This changes the number of multicast groups that are available 2120 * on a certain netlink family. Note that it is not possible to 2121 * change the number of groups to below 32. Also note that it does 2122 * not implicitly call netlink_clear_multicast_users() when the 2123 * number of groups is reduced. 2124 * 2125 * @sk: The kernel netlink socket, as returned by netlink_kernel_create(). 2126 * @groups: The new number of groups. 2127 */ 2128 int netlink_change_ngroups(struct sock *sk, unsigned int groups) 2129 { 2130 int err; 2131 2132 netlink_table_grab(); 2133 err = __netlink_change_ngroups(sk, groups); 2134 netlink_table_ungrab(); 2135 2136 return err; 2137 } 2138 2139 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group) 2140 { 2141 struct sock *sk; 2142 struct netlink_table *tbl = &nl_table[ksk->sk_protocol]; 2143 2144 sk_for_each_bound(sk, &tbl->mc_list) 2145 netlink_update_socket_mc(nlk_sk(sk), group, 0); 2146 } 2147 2148 struct nlmsghdr * 2149 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags) 2150 { 2151 struct nlmsghdr *nlh; 2152 int size = nlmsg_msg_size(len); 2153 2154 nlh = skb_put(skb, NLMSG_ALIGN(size)); 2155 nlh->nlmsg_type = type; 2156 nlh->nlmsg_len = size; 2157 nlh->nlmsg_flags = flags; 2158 nlh->nlmsg_pid = portid; 2159 nlh->nlmsg_seq = seq; 2160 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0) 2161 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size); 2162 return nlh; 2163 } 2164 EXPORT_SYMBOL(__nlmsg_put); 2165 2166 /* 2167 * It looks a bit ugly. 2168 * It would be better to create kernel thread. 2169 */ 2170 2171 static int netlink_dump(struct sock *sk) 2172 { 2173 struct netlink_sock *nlk = nlk_sk(sk); 2174 struct netlink_callback *cb; 2175 struct sk_buff *skb = NULL; 2176 struct nlmsghdr *nlh; 2177 struct module *module; 2178 int err = -ENOBUFS; 2179 int alloc_min_size; 2180 int alloc_size; 2181 2182 mutex_lock(nlk->cb_mutex); 2183 if (!nlk->cb_running) { 2184 err = -EINVAL; 2185 goto errout_skb; 2186 } 2187 2188 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) 2189 goto errout_skb; 2190 2191 /* NLMSG_GOODSIZE is small to avoid high order allocations being 2192 * required, but it makes sense to _attempt_ a 16K bytes allocation 2193 * to reduce number of system calls on dump operations, if user 2194 * ever provided a big enough buffer. 2195 */ 2196 cb = &nlk->cb; 2197 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); 2198 2199 if (alloc_min_size < nlk->max_recvmsg_len) { 2200 alloc_size = nlk->max_recvmsg_len; 2201 skb = alloc_skb(alloc_size, 2202 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) | 2203 __GFP_NOWARN | __GFP_NORETRY); 2204 } 2205 if (!skb) { 2206 alloc_size = alloc_min_size; 2207 skb = alloc_skb(alloc_size, GFP_KERNEL); 2208 } 2209 if (!skb) 2210 goto errout_skb; 2211 2212 /* Trim skb to allocated size. User is expected to provide buffer as 2213 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at 2214 * netlink_recvmsg())). dump will pack as many smaller messages as 2215 * could fit within the allocated skb. skb is typically allocated 2216 * with larger space than required (could be as much as near 2x the 2217 * requested size with align to next power of 2 approach). Allowing 2218 * dump to use the excess space makes it difficult for a user to have a 2219 * reasonable static buffer based on the expected largest dump of a 2220 * single netdev. The outcome is MSG_TRUNC error. 2221 */ 2222 skb_reserve(skb, skb_tailroom(skb) - alloc_size); 2223 netlink_skb_set_owner_r(skb, sk); 2224 2225 if (nlk->dump_done_errno > 0) 2226 nlk->dump_done_errno = cb->dump(skb, cb); 2227 2228 if (nlk->dump_done_errno > 0 || 2229 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) { 2230 mutex_unlock(nlk->cb_mutex); 2231 2232 if (sk_filter(sk, skb)) 2233 kfree_skb(skb); 2234 else 2235 __netlink_sendskb(sk, skb); 2236 return 0; 2237 } 2238 2239 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, 2240 sizeof(nlk->dump_done_errno), NLM_F_MULTI); 2241 if (WARN_ON(!nlh)) 2242 goto errout_skb; 2243 2244 nl_dump_check_consistent(cb, nlh); 2245 2246 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, 2247 sizeof(nlk->dump_done_errno)); 2248 2249 if (sk_filter(sk, skb)) 2250 kfree_skb(skb); 2251 else 2252 __netlink_sendskb(sk, skb); 2253 2254 if (cb->done) 2255 cb->done(cb); 2256 2257 nlk->cb_running = false; 2258 module = cb->module; 2259 skb = cb->skb; 2260 mutex_unlock(nlk->cb_mutex); 2261 module_put(module); 2262 consume_skb(skb); 2263 return 0; 2264 2265 errout_skb: 2266 mutex_unlock(nlk->cb_mutex); 2267 kfree_skb(skb); 2268 return err; 2269 } 2270 2271 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 2272 const struct nlmsghdr *nlh, 2273 struct netlink_dump_control *control) 2274 { 2275 struct netlink_callback *cb; 2276 struct sock *sk; 2277 struct netlink_sock *nlk; 2278 int ret; 2279 2280 refcount_inc(&skb->users); 2281 2282 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid); 2283 if (sk == NULL) { 2284 ret = -ECONNREFUSED; 2285 goto error_free; 2286 } 2287 2288 nlk = nlk_sk(sk); 2289 mutex_lock(nlk->cb_mutex); 2290 /* A dump is in progress... */ 2291 if (nlk->cb_running) { 2292 ret = -EBUSY; 2293 goto error_unlock; 2294 } 2295 /* add reference of module which cb->dump belongs to */ 2296 if (!try_module_get(control->module)) { 2297 ret = -EPROTONOSUPPORT; 2298 goto error_unlock; 2299 } 2300 2301 cb = &nlk->cb; 2302 memset(cb, 0, sizeof(*cb)); 2303 cb->start = control->start; 2304 cb->dump = control->dump; 2305 cb->done = control->done; 2306 cb->nlh = nlh; 2307 cb->data = control->data; 2308 cb->module = control->module; 2309 cb->min_dump_alloc = control->min_dump_alloc; 2310 cb->skb = skb; 2311 2312 if (cb->start) { 2313 ret = cb->start(cb); 2314 if (ret) 2315 goto error_put; 2316 } 2317 2318 nlk->cb_running = true; 2319 nlk->dump_done_errno = INT_MAX; 2320 2321 mutex_unlock(nlk->cb_mutex); 2322 2323 ret = netlink_dump(sk); 2324 2325 sock_put(sk); 2326 2327 if (ret) 2328 return ret; 2329 2330 /* We successfully started a dump, by returning -EINTR we 2331 * signal not to send ACK even if it was requested. 2332 */ 2333 return -EINTR; 2334 2335 error_put: 2336 module_put(control->module); 2337 error_unlock: 2338 sock_put(sk); 2339 mutex_unlock(nlk->cb_mutex); 2340 error_free: 2341 kfree_skb(skb); 2342 return ret; 2343 } 2344 EXPORT_SYMBOL(__netlink_dump_start); 2345 2346 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, 2347 const struct netlink_ext_ack *extack) 2348 { 2349 struct sk_buff *skb; 2350 struct nlmsghdr *rep; 2351 struct nlmsgerr *errmsg; 2352 size_t payload = sizeof(*errmsg); 2353 size_t tlvlen = 0; 2354 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk); 2355 unsigned int flags = 0; 2356 bool nlk_has_extack = nlk->flags & NETLINK_F_EXT_ACK; 2357 2358 /* Error messages get the original request appened, unless the user 2359 * requests to cap the error message, and get extra error data if 2360 * requested. 2361 */ 2362 if (nlk_has_extack && extack && extack->_msg) 2363 tlvlen += nla_total_size(strlen(extack->_msg) + 1); 2364 2365 if (err) { 2366 if (!(nlk->flags & NETLINK_F_CAP_ACK)) 2367 payload += nlmsg_len(nlh); 2368 else 2369 flags |= NLM_F_CAPPED; 2370 if (nlk_has_extack && extack && extack->bad_attr) 2371 tlvlen += nla_total_size(sizeof(u32)); 2372 } else { 2373 flags |= NLM_F_CAPPED; 2374 2375 if (nlk_has_extack && extack && extack->cookie_len) 2376 tlvlen += nla_total_size(extack->cookie_len); 2377 } 2378 2379 if (tlvlen) 2380 flags |= NLM_F_ACK_TLVS; 2381 2382 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL); 2383 if (!skb) { 2384 NETLINK_CB(in_skb).sk->sk_err = ENOBUFS; 2385 NETLINK_CB(in_skb).sk->sk_error_report(NETLINK_CB(in_skb).sk); 2386 return; 2387 } 2388 2389 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, 2390 NLMSG_ERROR, payload, flags); 2391 errmsg = nlmsg_data(rep); 2392 errmsg->error = err; 2393 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); 2394 2395 if (nlk_has_extack && extack) { 2396 if (extack->_msg) { 2397 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, 2398 extack->_msg)); 2399 } 2400 if (err) { 2401 if (extack->bad_attr && 2402 !WARN_ON((u8 *)extack->bad_attr < in_skb->data || 2403 (u8 *)extack->bad_attr >= in_skb->data + 2404 in_skb->len)) 2405 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS, 2406 (u8 *)extack->bad_attr - 2407 in_skb->data)); 2408 } else { 2409 if (extack->cookie_len) 2410 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE, 2411 extack->cookie_len, 2412 extack->cookie)); 2413 } 2414 } 2415 2416 nlmsg_end(skb, rep); 2417 2418 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT); 2419 } 2420 EXPORT_SYMBOL(netlink_ack); 2421 2422 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, 2423 struct nlmsghdr *, 2424 struct netlink_ext_ack *)) 2425 { 2426 struct netlink_ext_ack extack; 2427 struct nlmsghdr *nlh; 2428 int err; 2429 2430 while (skb->len >= nlmsg_total_size(0)) { 2431 int msglen; 2432 2433 memset(&extack, 0, sizeof(extack)); 2434 nlh = nlmsg_hdr(skb); 2435 err = 0; 2436 2437 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) 2438 return 0; 2439 2440 /* Only requests are handled by the kernel */ 2441 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) 2442 goto ack; 2443 2444 /* Skip control messages */ 2445 if (nlh->nlmsg_type < NLMSG_MIN_TYPE) 2446 goto ack; 2447 2448 err = cb(skb, nlh, &extack); 2449 if (err == -EINTR) 2450 goto skip; 2451 2452 ack: 2453 if (nlh->nlmsg_flags & NLM_F_ACK || err) 2454 netlink_ack(skb, nlh, err, &extack); 2455 2456 skip: 2457 msglen = NLMSG_ALIGN(nlh->nlmsg_len); 2458 if (msglen > skb->len) 2459 msglen = skb->len; 2460 skb_pull(skb, msglen); 2461 } 2462 2463 return 0; 2464 } 2465 EXPORT_SYMBOL(netlink_rcv_skb); 2466 2467 /** 2468 * nlmsg_notify - send a notification netlink message 2469 * @sk: netlink socket to use 2470 * @skb: notification message 2471 * @portid: destination netlink portid for reports or 0 2472 * @group: destination multicast group or 0 2473 * @report: 1 to report back, 0 to disable 2474 * @flags: allocation flags 2475 */ 2476 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid, 2477 unsigned int group, int report, gfp_t flags) 2478 { 2479 int err = 0; 2480 2481 if (group) { 2482 int exclude_portid = 0; 2483 2484 if (report) { 2485 refcount_inc(&skb->users); 2486 exclude_portid = portid; 2487 } 2488 2489 /* errors reported via destination sk->sk_err, but propagate 2490 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */ 2491 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags); 2492 } 2493 2494 if (report) { 2495 int err2; 2496 2497 err2 = nlmsg_unicast(sk, skb, portid); 2498 if (!err || err == -ESRCH) 2499 err = err2; 2500 } 2501 2502 return err; 2503 } 2504 EXPORT_SYMBOL(nlmsg_notify); 2505 2506 #ifdef CONFIG_PROC_FS 2507 struct nl_seq_iter { 2508 struct seq_net_private p; 2509 struct rhashtable_iter hti; 2510 int link; 2511 }; 2512 2513 static int netlink_walk_start(struct nl_seq_iter *iter) 2514 { 2515 int err; 2516 2517 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti, 2518 GFP_KERNEL); 2519 if (err) { 2520 iter->link = MAX_LINKS; 2521 return err; 2522 } 2523 2524 rhashtable_walk_start(&iter->hti); 2525 2526 return 0; 2527 } 2528 2529 static void netlink_walk_stop(struct nl_seq_iter *iter) 2530 { 2531 rhashtable_walk_stop(&iter->hti); 2532 rhashtable_walk_exit(&iter->hti); 2533 } 2534 2535 static void *__netlink_seq_next(struct seq_file *seq) 2536 { 2537 struct nl_seq_iter *iter = seq->private; 2538 struct netlink_sock *nlk; 2539 2540 do { 2541 for (;;) { 2542 int err; 2543 2544 nlk = rhashtable_walk_next(&iter->hti); 2545 2546 if (IS_ERR(nlk)) { 2547 if (PTR_ERR(nlk) == -EAGAIN) 2548 continue; 2549 2550 return nlk; 2551 } 2552 2553 if (nlk) 2554 break; 2555 2556 netlink_walk_stop(iter); 2557 if (++iter->link >= MAX_LINKS) 2558 return NULL; 2559 2560 err = netlink_walk_start(iter); 2561 if (err) 2562 return ERR_PTR(err); 2563 } 2564 } while (sock_net(&nlk->sk) != seq_file_net(seq)); 2565 2566 return nlk; 2567 } 2568 2569 static void *netlink_seq_start(struct seq_file *seq, loff_t *posp) 2570 { 2571 struct nl_seq_iter *iter = seq->private; 2572 void *obj = SEQ_START_TOKEN; 2573 loff_t pos; 2574 int err; 2575 2576 iter->link = 0; 2577 2578 err = netlink_walk_start(iter); 2579 if (err) 2580 return ERR_PTR(err); 2581 2582 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--) 2583 obj = __netlink_seq_next(seq); 2584 2585 return obj; 2586 } 2587 2588 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2589 { 2590 ++*pos; 2591 return __netlink_seq_next(seq); 2592 } 2593 2594 static void netlink_seq_stop(struct seq_file *seq, void *v) 2595 { 2596 struct nl_seq_iter *iter = seq->private; 2597 2598 if (iter->link >= MAX_LINKS) 2599 return; 2600 2601 netlink_walk_stop(iter); 2602 } 2603 2604 2605 static int netlink_seq_show(struct seq_file *seq, void *v) 2606 { 2607 if (v == SEQ_START_TOKEN) { 2608 seq_puts(seq, 2609 "sk Eth Pid Groups " 2610 "Rmem Wmem Dump Locks Drops Inode\n"); 2611 } else { 2612 struct sock *s = v; 2613 struct netlink_sock *nlk = nlk_sk(s); 2614 2615 seq_printf(seq, "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8d %-8lu\n", 2616 s, 2617 s->sk_protocol, 2618 nlk->portid, 2619 nlk->groups ? (u32)nlk->groups[0] : 0, 2620 sk_rmem_alloc_get(s), 2621 sk_wmem_alloc_get(s), 2622 nlk->cb_running, 2623 refcount_read(&s->sk_refcnt), 2624 atomic_read(&s->sk_drops), 2625 sock_i_ino(s) 2626 ); 2627 2628 } 2629 return 0; 2630 } 2631 2632 static const struct seq_operations netlink_seq_ops = { 2633 .start = netlink_seq_start, 2634 .next = netlink_seq_next, 2635 .stop = netlink_seq_stop, 2636 .show = netlink_seq_show, 2637 }; 2638 #endif 2639 2640 int netlink_register_notifier(struct notifier_block *nb) 2641 { 2642 return blocking_notifier_chain_register(&netlink_chain, nb); 2643 } 2644 EXPORT_SYMBOL(netlink_register_notifier); 2645 2646 int netlink_unregister_notifier(struct notifier_block *nb) 2647 { 2648 return blocking_notifier_chain_unregister(&netlink_chain, nb); 2649 } 2650 EXPORT_SYMBOL(netlink_unregister_notifier); 2651 2652 static const struct proto_ops netlink_ops = { 2653 .family = PF_NETLINK, 2654 .owner = THIS_MODULE, 2655 .release = netlink_release, 2656 .bind = netlink_bind, 2657 .connect = netlink_connect, 2658 .socketpair = sock_no_socketpair, 2659 .accept = sock_no_accept, 2660 .getname = netlink_getname, 2661 .poll_mask = datagram_poll_mask, 2662 .ioctl = netlink_ioctl, 2663 .listen = sock_no_listen, 2664 .shutdown = sock_no_shutdown, 2665 .setsockopt = netlink_setsockopt, 2666 .getsockopt = netlink_getsockopt, 2667 .sendmsg = netlink_sendmsg, 2668 .recvmsg = netlink_recvmsg, 2669 .mmap = sock_no_mmap, 2670 .sendpage = sock_no_sendpage, 2671 }; 2672 2673 static const struct net_proto_family netlink_family_ops = { 2674 .family = PF_NETLINK, 2675 .create = netlink_create, 2676 .owner = THIS_MODULE, /* for consistency 8) */ 2677 }; 2678 2679 static int __net_init netlink_net_init(struct net *net) 2680 { 2681 #ifdef CONFIG_PROC_FS 2682 if (!proc_create_net("netlink", 0, net->proc_net, &netlink_seq_ops, 2683 sizeof(struct nl_seq_iter))) 2684 return -ENOMEM; 2685 #endif 2686 return 0; 2687 } 2688 2689 static void __net_exit netlink_net_exit(struct net *net) 2690 { 2691 #ifdef CONFIG_PROC_FS 2692 remove_proc_entry("netlink", net->proc_net); 2693 #endif 2694 } 2695 2696 static void __init netlink_add_usersock_entry(void) 2697 { 2698 struct listeners *listeners; 2699 int groups = 32; 2700 2701 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2702 if (!listeners) 2703 panic("netlink_add_usersock_entry: Cannot allocate listeners\n"); 2704 2705 netlink_table_grab(); 2706 2707 nl_table[NETLINK_USERSOCK].groups = groups; 2708 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners); 2709 nl_table[NETLINK_USERSOCK].module = THIS_MODULE; 2710 nl_table[NETLINK_USERSOCK].registered = 1; 2711 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND; 2712 2713 netlink_table_ungrab(); 2714 } 2715 2716 static struct pernet_operations __net_initdata netlink_net_ops = { 2717 .init = netlink_net_init, 2718 .exit = netlink_net_exit, 2719 }; 2720 2721 static inline u32 netlink_hash(const void *data, u32 len, u32 seed) 2722 { 2723 const struct netlink_sock *nlk = data; 2724 struct netlink_compare_arg arg; 2725 2726 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid); 2727 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed); 2728 } 2729 2730 static const struct rhashtable_params netlink_rhashtable_params = { 2731 .head_offset = offsetof(struct netlink_sock, node), 2732 .key_len = netlink_compare_arg_len, 2733 .obj_hashfn = netlink_hash, 2734 .obj_cmpfn = netlink_compare, 2735 .automatic_shrinking = true, 2736 }; 2737 2738 static int __init netlink_proto_init(void) 2739 { 2740 int i; 2741 int err = proto_register(&netlink_proto, 0); 2742 2743 if (err != 0) 2744 goto out; 2745 2746 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb)); 2747 2748 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); 2749 if (!nl_table) 2750 goto panic; 2751 2752 for (i = 0; i < MAX_LINKS; i++) { 2753 if (rhashtable_init(&nl_table[i].hash, 2754 &netlink_rhashtable_params) < 0) { 2755 while (--i > 0) 2756 rhashtable_destroy(&nl_table[i].hash); 2757 kfree(nl_table); 2758 goto panic; 2759 } 2760 } 2761 2762 netlink_add_usersock_entry(); 2763 2764 sock_register(&netlink_family_ops); 2765 register_pernet_subsys(&netlink_net_ops); 2766 register_pernet_subsys(&netlink_tap_net_ops); 2767 /* The netlink device handler may be needed early. */ 2768 rtnetlink_init(); 2769 out: 2770 return err; 2771 panic: 2772 panic("netlink_init: Cannot allocate nl_table\n"); 2773 } 2774 2775 core_initcall(netlink_proto_init); 2776