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