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 *addr_len, 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 *addr_len = sizeof(*nladdr); 1120 1121 if (peer) { 1122 nladdr->nl_pid = nlk->dst_portid; 1123 nladdr->nl_groups = netlink_group_mask(nlk->dst_group); 1124 } else { 1125 nladdr->nl_pid = nlk->portid; 1126 netlink_lock_table(); 1127 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; 1128 netlink_unlock_table(); 1129 } 1130 return 0; 1131 } 1132 1133 static int netlink_ioctl(struct socket *sock, unsigned int cmd, 1134 unsigned long arg) 1135 { 1136 /* try to hand this ioctl down to the NIC drivers. 1137 */ 1138 return -ENOIOCTLCMD; 1139 } 1140 1141 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid) 1142 { 1143 struct sock *sock; 1144 struct netlink_sock *nlk; 1145 1146 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid); 1147 if (!sock) 1148 return ERR_PTR(-ECONNREFUSED); 1149 1150 /* Don't bother queuing skb if kernel socket has no input function */ 1151 nlk = nlk_sk(sock); 1152 if (sock->sk_state == NETLINK_CONNECTED && 1153 nlk->dst_portid != nlk_sk(ssk)->portid) { 1154 sock_put(sock); 1155 return ERR_PTR(-ECONNREFUSED); 1156 } 1157 return sock; 1158 } 1159 1160 struct sock *netlink_getsockbyfilp(struct file *filp) 1161 { 1162 struct inode *inode = file_inode(filp); 1163 struct sock *sock; 1164 1165 if (!S_ISSOCK(inode->i_mode)) 1166 return ERR_PTR(-ENOTSOCK); 1167 1168 sock = SOCKET_I(inode)->sk; 1169 if (sock->sk_family != AF_NETLINK) 1170 return ERR_PTR(-EINVAL); 1171 1172 sock_hold(sock); 1173 return sock; 1174 } 1175 1176 static struct sk_buff *netlink_alloc_large_skb(unsigned int size, 1177 int broadcast) 1178 { 1179 struct sk_buff *skb; 1180 void *data; 1181 1182 if (size <= NLMSG_GOODSIZE || broadcast) 1183 return alloc_skb(size, GFP_KERNEL); 1184 1185 size = SKB_DATA_ALIGN(size) + 1186 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 1187 1188 data = vmalloc(size); 1189 if (data == NULL) 1190 return NULL; 1191 1192 skb = __build_skb(data, size); 1193 if (skb == NULL) 1194 vfree(data); 1195 else 1196 skb->destructor = netlink_skb_destructor; 1197 1198 return skb; 1199 } 1200 1201 /* 1202 * Attach a skb to a netlink socket. 1203 * The caller must hold a reference to the destination socket. On error, the 1204 * reference is dropped. The skb is not send to the destination, just all 1205 * all error checks are performed and memory in the queue is reserved. 1206 * Return values: 1207 * < 0: error. skb freed, reference to sock dropped. 1208 * 0: continue 1209 * 1: repeat lookup - reference dropped while waiting for socket memory. 1210 */ 1211 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, 1212 long *timeo, struct sock *ssk) 1213 { 1214 struct netlink_sock *nlk; 1215 1216 nlk = nlk_sk(sk); 1217 1218 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 1219 test_bit(NETLINK_S_CONGESTED, &nlk->state))) { 1220 DECLARE_WAITQUEUE(wait, current); 1221 if (!*timeo) { 1222 if (!ssk || netlink_is_kernel(ssk)) 1223 netlink_overrun(sk); 1224 sock_put(sk); 1225 kfree_skb(skb); 1226 return -EAGAIN; 1227 } 1228 1229 __set_current_state(TASK_INTERRUPTIBLE); 1230 add_wait_queue(&nlk->wait, &wait); 1231 1232 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 1233 test_bit(NETLINK_S_CONGESTED, &nlk->state)) && 1234 !sock_flag(sk, SOCK_DEAD)) 1235 *timeo = schedule_timeout(*timeo); 1236 1237 __set_current_state(TASK_RUNNING); 1238 remove_wait_queue(&nlk->wait, &wait); 1239 sock_put(sk); 1240 1241 if (signal_pending(current)) { 1242 kfree_skb(skb); 1243 return sock_intr_errno(*timeo); 1244 } 1245 return 1; 1246 } 1247 netlink_skb_set_owner_r(skb, sk); 1248 return 0; 1249 } 1250 1251 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb) 1252 { 1253 int len = skb->len; 1254 1255 netlink_deliver_tap(sock_net(sk), skb); 1256 1257 skb_queue_tail(&sk->sk_receive_queue, skb); 1258 sk->sk_data_ready(sk); 1259 return len; 1260 } 1261 1262 int netlink_sendskb(struct sock *sk, struct sk_buff *skb) 1263 { 1264 int len = __netlink_sendskb(sk, skb); 1265 1266 sock_put(sk); 1267 return len; 1268 } 1269 1270 void netlink_detachskb(struct sock *sk, struct sk_buff *skb) 1271 { 1272 kfree_skb(skb); 1273 sock_put(sk); 1274 } 1275 1276 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation) 1277 { 1278 int delta; 1279 1280 WARN_ON(skb->sk != NULL); 1281 delta = skb->end - skb->tail; 1282 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize) 1283 return skb; 1284 1285 if (skb_shared(skb)) { 1286 struct sk_buff *nskb = skb_clone(skb, allocation); 1287 if (!nskb) 1288 return skb; 1289 consume_skb(skb); 1290 skb = nskb; 1291 } 1292 1293 pskb_expand_head(skb, 0, -delta, 1294 (allocation & ~__GFP_DIRECT_RECLAIM) | 1295 __GFP_NOWARN | __GFP_NORETRY); 1296 return skb; 1297 } 1298 1299 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb, 1300 struct sock *ssk) 1301 { 1302 int ret; 1303 struct netlink_sock *nlk = nlk_sk(sk); 1304 1305 ret = -ECONNREFUSED; 1306 if (nlk->netlink_rcv != NULL) { 1307 ret = skb->len; 1308 netlink_skb_set_owner_r(skb, sk); 1309 NETLINK_CB(skb).sk = ssk; 1310 netlink_deliver_tap_kernel(sk, ssk, skb); 1311 nlk->netlink_rcv(skb); 1312 consume_skb(skb); 1313 } else { 1314 kfree_skb(skb); 1315 } 1316 sock_put(sk); 1317 return ret; 1318 } 1319 1320 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, 1321 u32 portid, int nonblock) 1322 { 1323 struct sock *sk; 1324 int err; 1325 long timeo; 1326 1327 skb = netlink_trim(skb, gfp_any()); 1328 1329 timeo = sock_sndtimeo(ssk, nonblock); 1330 retry: 1331 sk = netlink_getsockbyportid(ssk, portid); 1332 if (IS_ERR(sk)) { 1333 kfree_skb(skb); 1334 return PTR_ERR(sk); 1335 } 1336 if (netlink_is_kernel(sk)) 1337 return netlink_unicast_kernel(sk, skb, ssk); 1338 1339 if (sk_filter(sk, skb)) { 1340 err = skb->len; 1341 kfree_skb(skb); 1342 sock_put(sk); 1343 return err; 1344 } 1345 1346 err = netlink_attachskb(sk, skb, &timeo, ssk); 1347 if (err == 1) 1348 goto retry; 1349 if (err) 1350 return err; 1351 1352 return netlink_sendskb(sk, skb); 1353 } 1354 EXPORT_SYMBOL(netlink_unicast); 1355 1356 int netlink_has_listeners(struct sock *sk, unsigned int group) 1357 { 1358 int res = 0; 1359 struct listeners *listeners; 1360 1361 BUG_ON(!netlink_is_kernel(sk)); 1362 1363 rcu_read_lock(); 1364 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners); 1365 1366 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups) 1367 res = test_bit(group - 1, listeners->masks); 1368 1369 rcu_read_unlock(); 1370 1371 return res; 1372 } 1373 EXPORT_SYMBOL_GPL(netlink_has_listeners); 1374 1375 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) 1376 { 1377 struct netlink_sock *nlk = nlk_sk(sk); 1378 1379 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && 1380 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) { 1381 netlink_skb_set_owner_r(skb, sk); 1382 __netlink_sendskb(sk, skb); 1383 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1); 1384 } 1385 return -1; 1386 } 1387 1388 struct netlink_broadcast_data { 1389 struct sock *exclude_sk; 1390 struct net *net; 1391 u32 portid; 1392 u32 group; 1393 int failure; 1394 int delivery_failure; 1395 int congested; 1396 int delivered; 1397 gfp_t allocation; 1398 struct sk_buff *skb, *skb2; 1399 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data); 1400 void *tx_data; 1401 }; 1402 1403 static void do_one_broadcast(struct sock *sk, 1404 struct netlink_broadcast_data *p) 1405 { 1406 struct netlink_sock *nlk = nlk_sk(sk); 1407 int val; 1408 1409 if (p->exclude_sk == sk) 1410 return; 1411 1412 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups || 1413 !test_bit(p->group - 1, nlk->groups)) 1414 return; 1415 1416 if (!net_eq(sock_net(sk), p->net)) { 1417 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID)) 1418 return; 1419 1420 if (!peernet_has_id(sock_net(sk), p->net)) 1421 return; 1422 1423 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns, 1424 CAP_NET_BROADCAST)) 1425 return; 1426 } 1427 1428 if (p->failure) { 1429 netlink_overrun(sk); 1430 return; 1431 } 1432 1433 sock_hold(sk); 1434 if (p->skb2 == NULL) { 1435 if (skb_shared(p->skb)) { 1436 p->skb2 = skb_clone(p->skb, p->allocation); 1437 } else { 1438 p->skb2 = skb_get(p->skb); 1439 /* 1440 * skb ownership may have been set when 1441 * delivered to a previous socket. 1442 */ 1443 skb_orphan(p->skb2); 1444 } 1445 } 1446 if (p->skb2 == NULL) { 1447 netlink_overrun(sk); 1448 /* Clone failed. Notify ALL listeners. */ 1449 p->failure = 1; 1450 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR) 1451 p->delivery_failure = 1; 1452 goto out; 1453 } 1454 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) { 1455 kfree_skb(p->skb2); 1456 p->skb2 = NULL; 1457 goto out; 1458 } 1459 if (sk_filter(sk, p->skb2)) { 1460 kfree_skb(p->skb2); 1461 p->skb2 = NULL; 1462 goto out; 1463 } 1464 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net); 1465 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED) 1466 NETLINK_CB(p->skb2).nsid_is_set = true; 1467 val = netlink_broadcast_deliver(sk, p->skb2); 1468 if (val < 0) { 1469 netlink_overrun(sk); 1470 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR) 1471 p->delivery_failure = 1; 1472 } else { 1473 p->congested |= val; 1474 p->delivered = 1; 1475 p->skb2 = NULL; 1476 } 1477 out: 1478 sock_put(sk); 1479 } 1480 1481 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid, 1482 u32 group, gfp_t allocation, 1483 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data), 1484 void *filter_data) 1485 { 1486 struct net *net = sock_net(ssk); 1487 struct netlink_broadcast_data info; 1488 struct sock *sk; 1489 1490 skb = netlink_trim(skb, allocation); 1491 1492 info.exclude_sk = ssk; 1493 info.net = net; 1494 info.portid = portid; 1495 info.group = group; 1496 info.failure = 0; 1497 info.delivery_failure = 0; 1498 info.congested = 0; 1499 info.delivered = 0; 1500 info.allocation = allocation; 1501 info.skb = skb; 1502 info.skb2 = NULL; 1503 info.tx_filter = filter; 1504 info.tx_data = filter_data; 1505 1506 /* While we sleep in clone, do not allow to change socket list */ 1507 1508 netlink_lock_table(); 1509 1510 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) 1511 do_one_broadcast(sk, &info); 1512 1513 consume_skb(skb); 1514 1515 netlink_unlock_table(); 1516 1517 if (info.delivery_failure) { 1518 kfree_skb(info.skb2); 1519 return -ENOBUFS; 1520 } 1521 consume_skb(info.skb2); 1522 1523 if (info.delivered) { 1524 if (info.congested && gfpflags_allow_blocking(allocation)) 1525 yield(); 1526 return 0; 1527 } 1528 return -ESRCH; 1529 } 1530 EXPORT_SYMBOL(netlink_broadcast_filtered); 1531 1532 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid, 1533 u32 group, gfp_t allocation) 1534 { 1535 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation, 1536 NULL, NULL); 1537 } 1538 EXPORT_SYMBOL(netlink_broadcast); 1539 1540 struct netlink_set_err_data { 1541 struct sock *exclude_sk; 1542 u32 portid; 1543 u32 group; 1544 int code; 1545 }; 1546 1547 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p) 1548 { 1549 struct netlink_sock *nlk = nlk_sk(sk); 1550 int ret = 0; 1551 1552 if (sk == p->exclude_sk) 1553 goto out; 1554 1555 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk))) 1556 goto out; 1557 1558 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups || 1559 !test_bit(p->group - 1, nlk->groups)) 1560 goto out; 1561 1562 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) { 1563 ret = 1; 1564 goto out; 1565 } 1566 1567 sk->sk_err = p->code; 1568 sk->sk_error_report(sk); 1569 out: 1570 return ret; 1571 } 1572 1573 /** 1574 * netlink_set_err - report error to broadcast listeners 1575 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create() 1576 * @portid: the PORTID of a process that we want to skip (if any) 1577 * @group: the broadcast group that will notice the error 1578 * @code: error code, must be negative (as usual in kernelspace) 1579 * 1580 * This function returns the number of broadcast listeners that have set the 1581 * NETLINK_NO_ENOBUFS socket option. 1582 */ 1583 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code) 1584 { 1585 struct netlink_set_err_data info; 1586 struct sock *sk; 1587 int ret = 0; 1588 1589 info.exclude_sk = ssk; 1590 info.portid = portid; 1591 info.group = group; 1592 /* sk->sk_err wants a positive error value */ 1593 info.code = -code; 1594 1595 read_lock(&nl_table_lock); 1596 1597 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) 1598 ret += do_one_set_err(sk, &info); 1599 1600 read_unlock(&nl_table_lock); 1601 return ret; 1602 } 1603 EXPORT_SYMBOL(netlink_set_err); 1604 1605 /* must be called with netlink table grabbed */ 1606 static void netlink_update_socket_mc(struct netlink_sock *nlk, 1607 unsigned int group, 1608 int is_new) 1609 { 1610 int old, new = !!is_new, subscriptions; 1611 1612 old = test_bit(group - 1, nlk->groups); 1613 subscriptions = nlk->subscriptions - old + new; 1614 if (new) 1615 __set_bit(group - 1, nlk->groups); 1616 else 1617 __clear_bit(group - 1, nlk->groups); 1618 netlink_update_subscriptions(&nlk->sk, subscriptions); 1619 netlink_update_listeners(&nlk->sk); 1620 } 1621 1622 static int netlink_setsockopt(struct socket *sock, int level, int optname, 1623 char __user *optval, unsigned int optlen) 1624 { 1625 struct sock *sk = sock->sk; 1626 struct netlink_sock *nlk = nlk_sk(sk); 1627 unsigned int val = 0; 1628 int err; 1629 1630 if (level != SOL_NETLINK) 1631 return -ENOPROTOOPT; 1632 1633 if (optlen >= sizeof(int) && 1634 get_user(val, (unsigned int __user *)optval)) 1635 return -EFAULT; 1636 1637 switch (optname) { 1638 case NETLINK_PKTINFO: 1639 if (val) 1640 nlk->flags |= NETLINK_F_RECV_PKTINFO; 1641 else 1642 nlk->flags &= ~NETLINK_F_RECV_PKTINFO; 1643 err = 0; 1644 break; 1645 case NETLINK_ADD_MEMBERSHIP: 1646 case NETLINK_DROP_MEMBERSHIP: { 1647 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) 1648 return -EPERM; 1649 err = netlink_realloc_groups(sk); 1650 if (err) 1651 return err; 1652 if (!val || val - 1 >= nlk->ngroups) 1653 return -EINVAL; 1654 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) { 1655 err = nlk->netlink_bind(sock_net(sk), val); 1656 if (err) 1657 return err; 1658 } 1659 netlink_table_grab(); 1660 netlink_update_socket_mc(nlk, val, 1661 optname == NETLINK_ADD_MEMBERSHIP); 1662 netlink_table_ungrab(); 1663 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind) 1664 nlk->netlink_unbind(sock_net(sk), val); 1665 1666 err = 0; 1667 break; 1668 } 1669 case NETLINK_BROADCAST_ERROR: 1670 if (val) 1671 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR; 1672 else 1673 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR; 1674 err = 0; 1675 break; 1676 case NETLINK_NO_ENOBUFS: 1677 if (val) { 1678 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS; 1679 clear_bit(NETLINK_S_CONGESTED, &nlk->state); 1680 wake_up_interruptible(&nlk->wait); 1681 } else { 1682 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS; 1683 } 1684 err = 0; 1685 break; 1686 case NETLINK_LISTEN_ALL_NSID: 1687 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST)) 1688 return -EPERM; 1689 1690 if (val) 1691 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID; 1692 else 1693 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID; 1694 err = 0; 1695 break; 1696 case NETLINK_CAP_ACK: 1697 if (val) 1698 nlk->flags |= NETLINK_F_CAP_ACK; 1699 else 1700 nlk->flags &= ~NETLINK_F_CAP_ACK; 1701 err = 0; 1702 break; 1703 case NETLINK_EXT_ACK: 1704 if (val) 1705 nlk->flags |= NETLINK_F_EXT_ACK; 1706 else 1707 nlk->flags &= ~NETLINK_F_EXT_ACK; 1708 err = 0; 1709 break; 1710 default: 1711 err = -ENOPROTOOPT; 1712 } 1713 return err; 1714 } 1715 1716 static int netlink_getsockopt(struct socket *sock, int level, int optname, 1717 char __user *optval, int __user *optlen) 1718 { 1719 struct sock *sk = sock->sk; 1720 struct netlink_sock *nlk = nlk_sk(sk); 1721 int len, val, err; 1722 1723 if (level != SOL_NETLINK) 1724 return -ENOPROTOOPT; 1725 1726 if (get_user(len, optlen)) 1727 return -EFAULT; 1728 if (len < 0) 1729 return -EINVAL; 1730 1731 switch (optname) { 1732 case NETLINK_PKTINFO: 1733 if (len < sizeof(int)) 1734 return -EINVAL; 1735 len = sizeof(int); 1736 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0; 1737 if (put_user(len, optlen) || 1738 put_user(val, optval)) 1739 return -EFAULT; 1740 err = 0; 1741 break; 1742 case NETLINK_BROADCAST_ERROR: 1743 if (len < sizeof(int)) 1744 return -EINVAL; 1745 len = sizeof(int); 1746 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0; 1747 if (put_user(len, optlen) || 1748 put_user(val, optval)) 1749 return -EFAULT; 1750 err = 0; 1751 break; 1752 case NETLINK_NO_ENOBUFS: 1753 if (len < sizeof(int)) 1754 return -EINVAL; 1755 len = sizeof(int); 1756 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0; 1757 if (put_user(len, optlen) || 1758 put_user(val, optval)) 1759 return -EFAULT; 1760 err = 0; 1761 break; 1762 case NETLINK_LIST_MEMBERSHIPS: { 1763 int pos, idx, shift; 1764 1765 err = 0; 1766 netlink_lock_table(); 1767 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) { 1768 if (len - pos < sizeof(u32)) 1769 break; 1770 1771 idx = pos / sizeof(unsigned long); 1772 shift = (pos % sizeof(unsigned long)) * 8; 1773 if (put_user((u32)(nlk->groups[idx] >> shift), 1774 (u32 __user *)(optval + pos))) { 1775 err = -EFAULT; 1776 break; 1777 } 1778 } 1779 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen)) 1780 err = -EFAULT; 1781 netlink_unlock_table(); 1782 break; 1783 } 1784 case NETLINK_CAP_ACK: 1785 if (len < sizeof(int)) 1786 return -EINVAL; 1787 len = sizeof(int); 1788 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0; 1789 if (put_user(len, optlen) || 1790 put_user(val, optval)) 1791 return -EFAULT; 1792 err = 0; 1793 break; 1794 case NETLINK_EXT_ACK: 1795 if (len < sizeof(int)) 1796 return -EINVAL; 1797 len = sizeof(int); 1798 val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0; 1799 if (put_user(len, optlen) || put_user(val, optval)) 1800 return -EFAULT; 1801 err = 0; 1802 break; 1803 default: 1804 err = -ENOPROTOOPT; 1805 } 1806 return err; 1807 } 1808 1809 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) 1810 { 1811 struct nl_pktinfo info; 1812 1813 info.group = NETLINK_CB(skb).dst_group; 1814 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); 1815 } 1816 1817 static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg, 1818 struct sk_buff *skb) 1819 { 1820 if (!NETLINK_CB(skb).nsid_is_set) 1821 return; 1822 1823 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int), 1824 &NETLINK_CB(skb).nsid); 1825 } 1826 1827 static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 1828 { 1829 struct sock *sk = sock->sk; 1830 struct netlink_sock *nlk = nlk_sk(sk); 1831 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); 1832 u32 dst_portid; 1833 u32 dst_group; 1834 struct sk_buff *skb; 1835 int err; 1836 struct scm_cookie scm; 1837 u32 netlink_skb_flags = 0; 1838 1839 if (msg->msg_flags&MSG_OOB) 1840 return -EOPNOTSUPP; 1841 1842 err = scm_send(sock, msg, &scm, true); 1843 if (err < 0) 1844 return err; 1845 1846 if (msg->msg_namelen) { 1847 err = -EINVAL; 1848 if (addr->nl_family != AF_NETLINK) 1849 goto out; 1850 dst_portid = addr->nl_pid; 1851 dst_group = ffs(addr->nl_groups); 1852 err = -EPERM; 1853 if ((dst_group || dst_portid) && 1854 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) 1855 goto out; 1856 netlink_skb_flags |= NETLINK_SKB_DST; 1857 } else { 1858 dst_portid = nlk->dst_portid; 1859 dst_group = nlk->dst_group; 1860 } 1861 1862 if (!nlk->bound) { 1863 err = netlink_autobind(sock); 1864 if (err) 1865 goto out; 1866 } else { 1867 /* Ensure nlk is hashed and visible. */ 1868 smp_rmb(); 1869 } 1870 1871 err = -EMSGSIZE; 1872 if (len > sk->sk_sndbuf - 32) 1873 goto out; 1874 err = -ENOBUFS; 1875 skb = netlink_alloc_large_skb(len, dst_group); 1876 if (skb == NULL) 1877 goto out; 1878 1879 NETLINK_CB(skb).portid = nlk->portid; 1880 NETLINK_CB(skb).dst_group = dst_group; 1881 NETLINK_CB(skb).creds = scm.creds; 1882 NETLINK_CB(skb).flags = netlink_skb_flags; 1883 1884 err = -EFAULT; 1885 if (memcpy_from_msg(skb_put(skb, len), msg, len)) { 1886 kfree_skb(skb); 1887 goto out; 1888 } 1889 1890 err = security_netlink_send(sk, skb); 1891 if (err) { 1892 kfree_skb(skb); 1893 goto out; 1894 } 1895 1896 if (dst_group) { 1897 refcount_inc(&skb->users); 1898 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL); 1899 } 1900 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT); 1901 1902 out: 1903 scm_destroy(&scm); 1904 return err; 1905 } 1906 1907 static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 1908 int flags) 1909 { 1910 struct scm_cookie scm; 1911 struct sock *sk = sock->sk; 1912 struct netlink_sock *nlk = nlk_sk(sk); 1913 int noblock = flags&MSG_DONTWAIT; 1914 size_t copied; 1915 struct sk_buff *skb, *data_skb; 1916 int err, ret; 1917 1918 if (flags&MSG_OOB) 1919 return -EOPNOTSUPP; 1920 1921 copied = 0; 1922 1923 skb = skb_recv_datagram(sk, flags, noblock, &err); 1924 if (skb == NULL) 1925 goto out; 1926 1927 data_skb = skb; 1928 1929 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES 1930 if (unlikely(skb_shinfo(skb)->frag_list)) { 1931 /* 1932 * If this skb has a frag_list, then here that means that we 1933 * will have to use the frag_list skb's data for compat tasks 1934 * and the regular skb's data for normal (non-compat) tasks. 1935 * 1936 * If we need to send the compat skb, assign it to the 1937 * 'data_skb' variable so that it will be used below for data 1938 * copying. We keep 'skb' for everything else, including 1939 * freeing both later. 1940 */ 1941 if (flags & MSG_CMSG_COMPAT) 1942 data_skb = skb_shinfo(skb)->frag_list; 1943 } 1944 #endif 1945 1946 /* Record the max length of recvmsg() calls for future allocations */ 1947 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len); 1948 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len, 1949 SKB_WITH_OVERHEAD(32768)); 1950 1951 copied = data_skb->len; 1952 if (len < copied) { 1953 msg->msg_flags |= MSG_TRUNC; 1954 copied = len; 1955 } 1956 1957 skb_reset_transport_header(data_skb); 1958 err = skb_copy_datagram_msg(data_skb, 0, msg, copied); 1959 1960 if (msg->msg_name) { 1961 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); 1962 addr->nl_family = AF_NETLINK; 1963 addr->nl_pad = 0; 1964 addr->nl_pid = NETLINK_CB(skb).portid; 1965 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); 1966 msg->msg_namelen = sizeof(*addr); 1967 } 1968 1969 if (nlk->flags & NETLINK_F_RECV_PKTINFO) 1970 netlink_cmsg_recv_pktinfo(msg, skb); 1971 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID) 1972 netlink_cmsg_listen_all_nsid(sk, msg, skb); 1973 1974 memset(&scm, 0, sizeof(scm)); 1975 scm.creds = *NETLINK_CREDS(skb); 1976 if (flags & MSG_TRUNC) 1977 copied = data_skb->len; 1978 1979 skb_free_datagram(sk, skb); 1980 1981 if (nlk->cb_running && 1982 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { 1983 ret = netlink_dump(sk); 1984 if (ret) { 1985 sk->sk_err = -ret; 1986 sk->sk_error_report(sk); 1987 } 1988 } 1989 1990 scm_recv(sock, msg, &scm, flags); 1991 out: 1992 netlink_rcv_wake(sk); 1993 return err ? : copied; 1994 } 1995 1996 static void netlink_data_ready(struct sock *sk) 1997 { 1998 BUG(); 1999 } 2000 2001 /* 2002 * We export these functions to other modules. They provide a 2003 * complete set of kernel non-blocking support for message 2004 * queueing. 2005 */ 2006 2007 struct sock * 2008 __netlink_kernel_create(struct net *net, int unit, struct module *module, 2009 struct netlink_kernel_cfg *cfg) 2010 { 2011 struct socket *sock; 2012 struct sock *sk; 2013 struct netlink_sock *nlk; 2014 struct listeners *listeners = NULL; 2015 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL; 2016 unsigned int groups; 2017 2018 BUG_ON(!nl_table); 2019 2020 if (unit < 0 || unit >= MAX_LINKS) 2021 return NULL; 2022 2023 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) 2024 return NULL; 2025 2026 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0) 2027 goto out_sock_release_nosk; 2028 2029 sk = sock->sk; 2030 2031 if (!cfg || cfg->groups < 32) 2032 groups = 32; 2033 else 2034 groups = cfg->groups; 2035 2036 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2037 if (!listeners) 2038 goto out_sock_release; 2039 2040 sk->sk_data_ready = netlink_data_ready; 2041 if (cfg && cfg->input) 2042 nlk_sk(sk)->netlink_rcv = cfg->input; 2043 2044 if (netlink_insert(sk, 0)) 2045 goto out_sock_release; 2046 2047 nlk = nlk_sk(sk); 2048 nlk->flags |= NETLINK_F_KERNEL_SOCKET; 2049 2050 netlink_table_grab(); 2051 if (!nl_table[unit].registered) { 2052 nl_table[unit].groups = groups; 2053 rcu_assign_pointer(nl_table[unit].listeners, listeners); 2054 nl_table[unit].cb_mutex = cb_mutex; 2055 nl_table[unit].module = module; 2056 if (cfg) { 2057 nl_table[unit].bind = cfg->bind; 2058 nl_table[unit].unbind = cfg->unbind; 2059 nl_table[unit].flags = cfg->flags; 2060 if (cfg->compare) 2061 nl_table[unit].compare = cfg->compare; 2062 } 2063 nl_table[unit].registered = 1; 2064 } else { 2065 kfree(listeners); 2066 nl_table[unit].registered++; 2067 } 2068 netlink_table_ungrab(); 2069 return sk; 2070 2071 out_sock_release: 2072 kfree(listeners); 2073 netlink_kernel_release(sk); 2074 return NULL; 2075 2076 out_sock_release_nosk: 2077 sock_release(sock); 2078 return NULL; 2079 } 2080 EXPORT_SYMBOL(__netlink_kernel_create); 2081 2082 void 2083 netlink_kernel_release(struct sock *sk) 2084 { 2085 if (sk == NULL || sk->sk_socket == NULL) 2086 return; 2087 2088 sock_release(sk->sk_socket); 2089 } 2090 EXPORT_SYMBOL(netlink_kernel_release); 2091 2092 int __netlink_change_ngroups(struct sock *sk, unsigned int groups) 2093 { 2094 struct listeners *new, *old; 2095 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 2096 2097 if (groups < 32) 2098 groups = 32; 2099 2100 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) { 2101 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC); 2102 if (!new) 2103 return -ENOMEM; 2104 old = nl_deref_protected(tbl->listeners); 2105 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups)); 2106 rcu_assign_pointer(tbl->listeners, new); 2107 2108 kfree_rcu(old, rcu); 2109 } 2110 tbl->groups = groups; 2111 2112 return 0; 2113 } 2114 2115 /** 2116 * netlink_change_ngroups - change number of multicast groups 2117 * 2118 * This changes the number of multicast groups that are available 2119 * on a certain netlink family. Note that it is not possible to 2120 * change the number of groups to below 32. Also note that it does 2121 * not implicitly call netlink_clear_multicast_users() when the 2122 * number of groups is reduced. 2123 * 2124 * @sk: The kernel netlink socket, as returned by netlink_kernel_create(). 2125 * @groups: The new number of groups. 2126 */ 2127 int netlink_change_ngroups(struct sock *sk, unsigned int groups) 2128 { 2129 int err; 2130 2131 netlink_table_grab(); 2132 err = __netlink_change_ngroups(sk, groups); 2133 netlink_table_ungrab(); 2134 2135 return err; 2136 } 2137 2138 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group) 2139 { 2140 struct sock *sk; 2141 struct netlink_table *tbl = &nl_table[ksk->sk_protocol]; 2142 2143 sk_for_each_bound(sk, &tbl->mc_list) 2144 netlink_update_socket_mc(nlk_sk(sk), group, 0); 2145 } 2146 2147 struct nlmsghdr * 2148 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags) 2149 { 2150 struct nlmsghdr *nlh; 2151 int size = nlmsg_msg_size(len); 2152 2153 nlh = skb_put(skb, NLMSG_ALIGN(size)); 2154 nlh->nlmsg_type = type; 2155 nlh->nlmsg_len = size; 2156 nlh->nlmsg_flags = flags; 2157 nlh->nlmsg_pid = portid; 2158 nlh->nlmsg_seq = seq; 2159 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0) 2160 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size); 2161 return nlh; 2162 } 2163 EXPORT_SYMBOL(__nlmsg_put); 2164 2165 /* 2166 * It looks a bit ugly. 2167 * It would be better to create kernel thread. 2168 */ 2169 2170 static int netlink_dump(struct sock *sk) 2171 { 2172 struct netlink_sock *nlk = nlk_sk(sk); 2173 struct netlink_callback *cb; 2174 struct sk_buff *skb = NULL; 2175 struct nlmsghdr *nlh; 2176 struct module *module; 2177 int err = -ENOBUFS; 2178 int alloc_min_size; 2179 int alloc_size; 2180 2181 mutex_lock(nlk->cb_mutex); 2182 if (!nlk->cb_running) { 2183 err = -EINVAL; 2184 goto errout_skb; 2185 } 2186 2187 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) 2188 goto errout_skb; 2189 2190 /* NLMSG_GOODSIZE is small to avoid high order allocations being 2191 * required, but it makes sense to _attempt_ a 16K bytes allocation 2192 * to reduce number of system calls on dump operations, if user 2193 * ever provided a big enough buffer. 2194 */ 2195 cb = &nlk->cb; 2196 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); 2197 2198 if (alloc_min_size < nlk->max_recvmsg_len) { 2199 alloc_size = nlk->max_recvmsg_len; 2200 skb = alloc_skb(alloc_size, 2201 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) | 2202 __GFP_NOWARN | __GFP_NORETRY); 2203 } 2204 if (!skb) { 2205 alloc_size = alloc_min_size; 2206 skb = alloc_skb(alloc_size, GFP_KERNEL); 2207 } 2208 if (!skb) 2209 goto errout_skb; 2210 2211 /* Trim skb to allocated size. User is expected to provide buffer as 2212 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at 2213 * netlink_recvmsg())). dump will pack as many smaller messages as 2214 * could fit within the allocated skb. skb is typically allocated 2215 * with larger space than required (could be as much as near 2x the 2216 * requested size with align to next power of 2 approach). Allowing 2217 * dump to use the excess space makes it difficult for a user to have a 2218 * reasonable static buffer based on the expected largest dump of a 2219 * single netdev. The outcome is MSG_TRUNC error. 2220 */ 2221 skb_reserve(skb, skb_tailroom(skb) - alloc_size); 2222 netlink_skb_set_owner_r(skb, sk); 2223 2224 if (nlk->dump_done_errno > 0) 2225 nlk->dump_done_errno = cb->dump(skb, cb); 2226 2227 if (nlk->dump_done_errno > 0 || 2228 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) { 2229 mutex_unlock(nlk->cb_mutex); 2230 2231 if (sk_filter(sk, skb)) 2232 kfree_skb(skb); 2233 else 2234 __netlink_sendskb(sk, skb); 2235 return 0; 2236 } 2237 2238 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, 2239 sizeof(nlk->dump_done_errno), NLM_F_MULTI); 2240 if (WARN_ON(!nlh)) 2241 goto errout_skb; 2242 2243 nl_dump_check_consistent(cb, nlh); 2244 2245 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, 2246 sizeof(nlk->dump_done_errno)); 2247 2248 if (sk_filter(sk, skb)) 2249 kfree_skb(skb); 2250 else 2251 __netlink_sendskb(sk, skb); 2252 2253 if (cb->done) 2254 cb->done(cb); 2255 2256 nlk->cb_running = false; 2257 module = cb->module; 2258 skb = cb->skb; 2259 mutex_unlock(nlk->cb_mutex); 2260 module_put(module); 2261 consume_skb(skb); 2262 return 0; 2263 2264 errout_skb: 2265 mutex_unlock(nlk->cb_mutex); 2266 kfree_skb(skb); 2267 return err; 2268 } 2269 2270 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 2271 const struct nlmsghdr *nlh, 2272 struct netlink_dump_control *control) 2273 { 2274 struct netlink_callback *cb; 2275 struct sock *sk; 2276 struct netlink_sock *nlk; 2277 int ret; 2278 2279 refcount_inc(&skb->users); 2280 2281 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid); 2282 if (sk == NULL) { 2283 ret = -ECONNREFUSED; 2284 goto error_free; 2285 } 2286 2287 nlk = nlk_sk(sk); 2288 mutex_lock(nlk->cb_mutex); 2289 /* A dump is in progress... */ 2290 if (nlk->cb_running) { 2291 ret = -EBUSY; 2292 goto error_unlock; 2293 } 2294 /* add reference of module which cb->dump belongs to */ 2295 if (!try_module_get(control->module)) { 2296 ret = -EPROTONOSUPPORT; 2297 goto error_unlock; 2298 } 2299 2300 cb = &nlk->cb; 2301 memset(cb, 0, sizeof(*cb)); 2302 cb->start = control->start; 2303 cb->dump = control->dump; 2304 cb->done = control->done; 2305 cb->nlh = nlh; 2306 cb->data = control->data; 2307 cb->module = control->module; 2308 cb->min_dump_alloc = control->min_dump_alloc; 2309 cb->skb = skb; 2310 2311 if (cb->start) { 2312 ret = cb->start(cb); 2313 if (ret) 2314 goto error_put; 2315 } 2316 2317 nlk->cb_running = true; 2318 nlk->dump_done_errno = INT_MAX; 2319 2320 mutex_unlock(nlk->cb_mutex); 2321 2322 ret = netlink_dump(sk); 2323 2324 sock_put(sk); 2325 2326 if (ret) 2327 return ret; 2328 2329 /* We successfully started a dump, by returning -EINTR we 2330 * signal not to send ACK even if it was requested. 2331 */ 2332 return -EINTR; 2333 2334 error_put: 2335 module_put(control->module); 2336 error_unlock: 2337 sock_put(sk); 2338 mutex_unlock(nlk->cb_mutex); 2339 error_free: 2340 kfree_skb(skb); 2341 return ret; 2342 } 2343 EXPORT_SYMBOL(__netlink_dump_start); 2344 2345 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, 2346 const struct netlink_ext_ack *extack) 2347 { 2348 struct sk_buff *skb; 2349 struct nlmsghdr *rep; 2350 struct nlmsgerr *errmsg; 2351 size_t payload = sizeof(*errmsg); 2352 size_t tlvlen = 0; 2353 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk); 2354 unsigned int flags = 0; 2355 bool nlk_has_extack = nlk->flags & NETLINK_F_EXT_ACK; 2356 2357 /* Error messages get the original request appened, unless the user 2358 * requests to cap the error message, and get extra error data if 2359 * requested. 2360 */ 2361 if (nlk_has_extack && extack && extack->_msg) 2362 tlvlen += nla_total_size(strlen(extack->_msg) + 1); 2363 2364 if (err) { 2365 if (!(nlk->flags & NETLINK_F_CAP_ACK)) 2366 payload += nlmsg_len(nlh); 2367 else 2368 flags |= NLM_F_CAPPED; 2369 if (nlk_has_extack && extack && extack->bad_attr) 2370 tlvlen += nla_total_size(sizeof(u32)); 2371 } else { 2372 flags |= NLM_F_CAPPED; 2373 2374 if (nlk_has_extack && extack && extack->cookie_len) 2375 tlvlen += nla_total_size(extack->cookie_len); 2376 } 2377 2378 if (tlvlen) 2379 flags |= NLM_F_ACK_TLVS; 2380 2381 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL); 2382 if (!skb) { 2383 NETLINK_CB(in_skb).sk->sk_err = ENOBUFS; 2384 NETLINK_CB(in_skb).sk->sk_error_report(NETLINK_CB(in_skb).sk); 2385 return; 2386 } 2387 2388 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, 2389 NLMSG_ERROR, payload, flags); 2390 errmsg = nlmsg_data(rep); 2391 errmsg->error = err; 2392 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); 2393 2394 if (nlk_has_extack && extack) { 2395 if (extack->_msg) { 2396 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, 2397 extack->_msg)); 2398 } 2399 if (err) { 2400 if (extack->bad_attr && 2401 !WARN_ON((u8 *)extack->bad_attr < in_skb->data || 2402 (u8 *)extack->bad_attr >= in_skb->data + 2403 in_skb->len)) 2404 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS, 2405 (u8 *)extack->bad_attr - 2406 in_skb->data)); 2407 } else { 2408 if (extack->cookie_len) 2409 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE, 2410 extack->cookie_len, 2411 extack->cookie)); 2412 } 2413 } 2414 2415 nlmsg_end(skb, rep); 2416 2417 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT); 2418 } 2419 EXPORT_SYMBOL(netlink_ack); 2420 2421 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, 2422 struct nlmsghdr *, 2423 struct netlink_ext_ack *)) 2424 { 2425 struct netlink_ext_ack extack; 2426 struct nlmsghdr *nlh; 2427 int err; 2428 2429 while (skb->len >= nlmsg_total_size(0)) { 2430 int msglen; 2431 2432 memset(&extack, 0, sizeof(extack)); 2433 nlh = nlmsg_hdr(skb); 2434 err = 0; 2435 2436 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) 2437 return 0; 2438 2439 /* Only requests are handled by the kernel */ 2440 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) 2441 goto ack; 2442 2443 /* Skip control messages */ 2444 if (nlh->nlmsg_type < NLMSG_MIN_TYPE) 2445 goto ack; 2446 2447 err = cb(skb, nlh, &extack); 2448 if (err == -EINTR) 2449 goto skip; 2450 2451 ack: 2452 if (nlh->nlmsg_flags & NLM_F_ACK || err) 2453 netlink_ack(skb, nlh, err, &extack); 2454 2455 skip: 2456 msglen = NLMSG_ALIGN(nlh->nlmsg_len); 2457 if (msglen > skb->len) 2458 msglen = skb->len; 2459 skb_pull(skb, msglen); 2460 } 2461 2462 return 0; 2463 } 2464 EXPORT_SYMBOL(netlink_rcv_skb); 2465 2466 /** 2467 * nlmsg_notify - send a notification netlink message 2468 * @sk: netlink socket to use 2469 * @skb: notification message 2470 * @portid: destination netlink portid for reports or 0 2471 * @group: destination multicast group or 0 2472 * @report: 1 to report back, 0 to disable 2473 * @flags: allocation flags 2474 */ 2475 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid, 2476 unsigned int group, int report, gfp_t flags) 2477 { 2478 int err = 0; 2479 2480 if (group) { 2481 int exclude_portid = 0; 2482 2483 if (report) { 2484 refcount_inc(&skb->users); 2485 exclude_portid = portid; 2486 } 2487 2488 /* errors reported via destination sk->sk_err, but propagate 2489 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */ 2490 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags); 2491 } 2492 2493 if (report) { 2494 int err2; 2495 2496 err2 = nlmsg_unicast(sk, skb, portid); 2497 if (!err || err == -ESRCH) 2498 err = err2; 2499 } 2500 2501 return err; 2502 } 2503 EXPORT_SYMBOL(nlmsg_notify); 2504 2505 #ifdef CONFIG_PROC_FS 2506 struct nl_seq_iter { 2507 struct seq_net_private p; 2508 struct rhashtable_iter hti; 2509 int link; 2510 }; 2511 2512 static int netlink_walk_start(struct nl_seq_iter *iter) 2513 { 2514 int err; 2515 2516 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti, 2517 GFP_KERNEL); 2518 if (err) { 2519 iter->link = MAX_LINKS; 2520 return err; 2521 } 2522 2523 rhashtable_walk_start(&iter->hti); 2524 2525 return 0; 2526 } 2527 2528 static void netlink_walk_stop(struct nl_seq_iter *iter) 2529 { 2530 rhashtable_walk_stop(&iter->hti); 2531 rhashtable_walk_exit(&iter->hti); 2532 } 2533 2534 static void *__netlink_seq_next(struct seq_file *seq) 2535 { 2536 struct nl_seq_iter *iter = seq->private; 2537 struct netlink_sock *nlk; 2538 2539 do { 2540 for (;;) { 2541 int err; 2542 2543 nlk = rhashtable_walk_next(&iter->hti); 2544 2545 if (IS_ERR(nlk)) { 2546 if (PTR_ERR(nlk) == -EAGAIN) 2547 continue; 2548 2549 return nlk; 2550 } 2551 2552 if (nlk) 2553 break; 2554 2555 netlink_walk_stop(iter); 2556 if (++iter->link >= MAX_LINKS) 2557 return NULL; 2558 2559 err = netlink_walk_start(iter); 2560 if (err) 2561 return ERR_PTR(err); 2562 } 2563 } while (sock_net(&nlk->sk) != seq_file_net(seq)); 2564 2565 return nlk; 2566 } 2567 2568 static void *netlink_seq_start(struct seq_file *seq, loff_t *posp) 2569 { 2570 struct nl_seq_iter *iter = seq->private; 2571 void *obj = SEQ_START_TOKEN; 2572 loff_t pos; 2573 int err; 2574 2575 iter->link = 0; 2576 2577 err = netlink_walk_start(iter); 2578 if (err) 2579 return ERR_PTR(err); 2580 2581 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--) 2582 obj = __netlink_seq_next(seq); 2583 2584 return obj; 2585 } 2586 2587 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2588 { 2589 ++*pos; 2590 return __netlink_seq_next(seq); 2591 } 2592 2593 static void netlink_seq_stop(struct seq_file *seq, void *v) 2594 { 2595 struct nl_seq_iter *iter = seq->private; 2596 2597 if (iter->link >= MAX_LINKS) 2598 return; 2599 2600 netlink_walk_stop(iter); 2601 } 2602 2603 2604 static int netlink_seq_show(struct seq_file *seq, void *v) 2605 { 2606 if (v == SEQ_START_TOKEN) { 2607 seq_puts(seq, 2608 "sk Eth Pid Groups " 2609 "Rmem Wmem Dump Locks Drops Inode\n"); 2610 } else { 2611 struct sock *s = v; 2612 struct netlink_sock *nlk = nlk_sk(s); 2613 2614 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n", 2615 s, 2616 s->sk_protocol, 2617 nlk->portid, 2618 nlk->groups ? (u32)nlk->groups[0] : 0, 2619 sk_rmem_alloc_get(s), 2620 sk_wmem_alloc_get(s), 2621 nlk->cb_running, 2622 refcount_read(&s->sk_refcnt), 2623 atomic_read(&s->sk_drops), 2624 sock_i_ino(s) 2625 ); 2626 2627 } 2628 return 0; 2629 } 2630 2631 static const struct seq_operations netlink_seq_ops = { 2632 .start = netlink_seq_start, 2633 .next = netlink_seq_next, 2634 .stop = netlink_seq_stop, 2635 .show = netlink_seq_show, 2636 }; 2637 2638 2639 static int netlink_seq_open(struct inode *inode, struct file *file) 2640 { 2641 return seq_open_net(inode, file, &netlink_seq_ops, 2642 sizeof(struct nl_seq_iter)); 2643 } 2644 2645 static const struct file_operations netlink_seq_fops = { 2646 .open = netlink_seq_open, 2647 .read = seq_read, 2648 .llseek = seq_lseek, 2649 .release = seq_release_net, 2650 }; 2651 2652 #endif 2653 2654 int netlink_register_notifier(struct notifier_block *nb) 2655 { 2656 return blocking_notifier_chain_register(&netlink_chain, nb); 2657 } 2658 EXPORT_SYMBOL(netlink_register_notifier); 2659 2660 int netlink_unregister_notifier(struct notifier_block *nb) 2661 { 2662 return blocking_notifier_chain_unregister(&netlink_chain, nb); 2663 } 2664 EXPORT_SYMBOL(netlink_unregister_notifier); 2665 2666 static const struct proto_ops netlink_ops = { 2667 .family = PF_NETLINK, 2668 .owner = THIS_MODULE, 2669 .release = netlink_release, 2670 .bind = netlink_bind, 2671 .connect = netlink_connect, 2672 .socketpair = sock_no_socketpair, 2673 .accept = sock_no_accept, 2674 .getname = netlink_getname, 2675 .poll = datagram_poll, 2676 .ioctl = netlink_ioctl, 2677 .listen = sock_no_listen, 2678 .shutdown = sock_no_shutdown, 2679 .setsockopt = netlink_setsockopt, 2680 .getsockopt = netlink_getsockopt, 2681 .sendmsg = netlink_sendmsg, 2682 .recvmsg = netlink_recvmsg, 2683 .mmap = sock_no_mmap, 2684 .sendpage = sock_no_sendpage, 2685 }; 2686 2687 static const struct net_proto_family netlink_family_ops = { 2688 .family = PF_NETLINK, 2689 .create = netlink_create, 2690 .owner = THIS_MODULE, /* for consistency 8) */ 2691 }; 2692 2693 static int __net_init netlink_net_init(struct net *net) 2694 { 2695 #ifdef CONFIG_PROC_FS 2696 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops)) 2697 return -ENOMEM; 2698 #endif 2699 return 0; 2700 } 2701 2702 static void __net_exit netlink_net_exit(struct net *net) 2703 { 2704 #ifdef CONFIG_PROC_FS 2705 remove_proc_entry("netlink", net->proc_net); 2706 #endif 2707 } 2708 2709 static void __init netlink_add_usersock_entry(void) 2710 { 2711 struct listeners *listeners; 2712 int groups = 32; 2713 2714 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2715 if (!listeners) 2716 panic("netlink_add_usersock_entry: Cannot allocate listeners\n"); 2717 2718 netlink_table_grab(); 2719 2720 nl_table[NETLINK_USERSOCK].groups = groups; 2721 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners); 2722 nl_table[NETLINK_USERSOCK].module = THIS_MODULE; 2723 nl_table[NETLINK_USERSOCK].registered = 1; 2724 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND; 2725 2726 netlink_table_ungrab(); 2727 } 2728 2729 static struct pernet_operations __net_initdata netlink_net_ops = { 2730 .init = netlink_net_init, 2731 .exit = netlink_net_exit, 2732 }; 2733 2734 static inline u32 netlink_hash(const void *data, u32 len, u32 seed) 2735 { 2736 const struct netlink_sock *nlk = data; 2737 struct netlink_compare_arg arg; 2738 2739 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid); 2740 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed); 2741 } 2742 2743 static const struct rhashtable_params netlink_rhashtable_params = { 2744 .head_offset = offsetof(struct netlink_sock, node), 2745 .key_len = netlink_compare_arg_len, 2746 .obj_hashfn = netlink_hash, 2747 .obj_cmpfn = netlink_compare, 2748 .automatic_shrinking = true, 2749 }; 2750 2751 static int __init netlink_proto_init(void) 2752 { 2753 int i; 2754 int err = proto_register(&netlink_proto, 0); 2755 2756 if (err != 0) 2757 goto out; 2758 2759 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb)); 2760 2761 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); 2762 if (!nl_table) 2763 goto panic; 2764 2765 for (i = 0; i < MAX_LINKS; i++) { 2766 if (rhashtable_init(&nl_table[i].hash, 2767 &netlink_rhashtable_params) < 0) { 2768 while (--i > 0) 2769 rhashtable_destroy(&nl_table[i].hash); 2770 kfree(nl_table); 2771 goto panic; 2772 } 2773 } 2774 2775 netlink_add_usersock_entry(); 2776 2777 sock_register(&netlink_family_ops); 2778 register_pernet_subsys(&netlink_net_ops); 2779 register_pernet_subsys(&netlink_tap_net_ops); 2780 /* The netlink device handler may be needed early. */ 2781 rtnetlink_init(); 2782 out: 2783 return err; 2784 panic: 2785 panic("netlink_init: Cannot allocate nl_table\n"); 2786 } 2787 2788 core_initcall(netlink_proto_init); 2789