1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * NETLINK Kernel-user communication protocol. 4 * 5 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk> 6 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 7 * Patrick McHardy <kaber@trash.net> 8 * 9 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith 10 * added netlink_proto_exit 11 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br> 12 * use nlk_sk, as sk->protinfo is on a diet 8) 13 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org> 14 * - inc module use count of module that owns 15 * the kernel socket in case userspace opens 16 * socket of same protocol 17 * - remove all module support, since netlink is 18 * mandatory if CONFIG_NET=y these days 19 */ 20 21 #include <linux/module.h> 22 23 #include <linux/bpf.h> 24 #include <linux/capability.h> 25 #include <linux/kernel.h> 26 #include <linux/filter.h> 27 #include <linux/init.h> 28 #include <linux/signal.h> 29 #include <linux/sched.h> 30 #include <linux/errno.h> 31 #include <linux/string.h> 32 #include <linux/stat.h> 33 #include <linux/socket.h> 34 #include <linux/un.h> 35 #include <linux/fcntl.h> 36 #include <linux/termios.h> 37 #include <linux/sockios.h> 38 #include <linux/net.h> 39 #include <linux/fs.h> 40 #include <linux/slab.h> 41 #include <linux/uaccess.h> 42 #include <linux/skbuff.h> 43 #include <linux/netdevice.h> 44 #include <linux/rtnetlink.h> 45 #include <linux/proc_fs.h> 46 #include <linux/seq_file.h> 47 #include <linux/notifier.h> 48 #include <linux/security.h> 49 #include <linux/jhash.h> 50 #include <linux/jiffies.h> 51 #include <linux/random.h> 52 #include <linux/bitops.h> 53 #include <linux/mm.h> 54 #include <linux/types.h> 55 #include <linux/audit.h> 56 #include <linux/mutex.h> 57 #include <linux/vmalloc.h> 58 #include <linux/if_arp.h> 59 #include <linux/rhashtable.h> 60 #include <asm/cacheflush.h> 61 #include <linux/hash.h> 62 #include <linux/genetlink.h> 63 #include <linux/net_namespace.h> 64 #include <linux/nospec.h> 65 #include <linux/btf_ids.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 #define CREATE_TRACE_POINTS 73 #include <trace/events/netlink.h> 74 75 #include "af_netlink.h" 76 77 struct listeners { 78 struct rcu_head rcu; 79 unsigned long masks[]; 80 }; 81 82 /* state bits */ 83 #define NETLINK_S_CONGESTED 0x0 84 85 static inline int netlink_is_kernel(struct sock *sk) 86 { 87 return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET; 88 } 89 90 struct netlink_table *nl_table __read_mostly; 91 EXPORT_SYMBOL_GPL(nl_table); 92 93 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); 94 95 static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS]; 96 97 static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = { 98 "nlk_cb_mutex-ROUTE", 99 "nlk_cb_mutex-1", 100 "nlk_cb_mutex-USERSOCK", 101 "nlk_cb_mutex-FIREWALL", 102 "nlk_cb_mutex-SOCK_DIAG", 103 "nlk_cb_mutex-NFLOG", 104 "nlk_cb_mutex-XFRM", 105 "nlk_cb_mutex-SELINUX", 106 "nlk_cb_mutex-ISCSI", 107 "nlk_cb_mutex-AUDIT", 108 "nlk_cb_mutex-FIB_LOOKUP", 109 "nlk_cb_mutex-CONNECTOR", 110 "nlk_cb_mutex-NETFILTER", 111 "nlk_cb_mutex-IP6_FW", 112 "nlk_cb_mutex-DNRTMSG", 113 "nlk_cb_mutex-KOBJECT_UEVENT", 114 "nlk_cb_mutex-GENERIC", 115 "nlk_cb_mutex-17", 116 "nlk_cb_mutex-SCSITRANSPORT", 117 "nlk_cb_mutex-ECRYPTFS", 118 "nlk_cb_mutex-RDMA", 119 "nlk_cb_mutex-CRYPTO", 120 "nlk_cb_mutex-SMC", 121 "nlk_cb_mutex-23", 122 "nlk_cb_mutex-24", 123 "nlk_cb_mutex-25", 124 "nlk_cb_mutex-26", 125 "nlk_cb_mutex-27", 126 "nlk_cb_mutex-28", 127 "nlk_cb_mutex-29", 128 "nlk_cb_mutex-30", 129 "nlk_cb_mutex-31", 130 "nlk_cb_mutex-MAX_LINKS" 131 }; 132 133 static int netlink_dump(struct sock *sk); 134 135 /* nl_table locking explained: 136 * Lookup and traversal are protected with an RCU read-side lock. Insertion 137 * and removal are protected with per bucket lock while using RCU list 138 * modification primitives and may run in parallel to RCU protected lookups. 139 * Destruction of the Netlink socket may only occur *after* nl_table_lock has 140 * been acquired * either during or after the socket has been removed from 141 * the list and after an RCU grace period. 142 */ 143 DEFINE_RWLOCK(nl_table_lock); 144 EXPORT_SYMBOL_GPL(nl_table_lock); 145 static atomic_t nl_table_users = ATOMIC_INIT(0); 146 147 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock)); 148 149 static BLOCKING_NOTIFIER_HEAD(netlink_chain); 150 151 152 static const struct rhashtable_params netlink_rhashtable_params; 153 154 void do_trace_netlink_extack(const char *msg) 155 { 156 trace_netlink_extack(msg); 157 } 158 EXPORT_SYMBOL(do_trace_netlink_extack); 159 160 static inline u32 netlink_group_mask(u32 group) 161 { 162 if (group > 32) 163 return 0; 164 return group ? 1 << (group - 1) : 0; 165 } 166 167 static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb, 168 gfp_t gfp_mask) 169 { 170 unsigned int len = skb_end_offset(skb); 171 struct sk_buff *new; 172 173 new = alloc_skb(len, gfp_mask); 174 if (new == NULL) 175 return NULL; 176 177 NETLINK_CB(new).portid = NETLINK_CB(skb).portid; 178 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group; 179 NETLINK_CB(new).creds = NETLINK_CB(skb).creds; 180 181 skb_put_data(new, skb->data, len); 182 return new; 183 } 184 185 static unsigned int netlink_tap_net_id; 186 187 struct netlink_tap_net { 188 struct list_head netlink_tap_all; 189 struct mutex netlink_tap_lock; 190 }; 191 192 int netlink_add_tap(struct netlink_tap *nt) 193 { 194 struct net *net = dev_net(nt->dev); 195 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 196 197 if (unlikely(nt->dev->type != ARPHRD_NETLINK)) 198 return -EINVAL; 199 200 mutex_lock(&nn->netlink_tap_lock); 201 list_add_rcu(&nt->list, &nn->netlink_tap_all); 202 mutex_unlock(&nn->netlink_tap_lock); 203 204 __module_get(nt->module); 205 206 return 0; 207 } 208 EXPORT_SYMBOL_GPL(netlink_add_tap); 209 210 static int __netlink_remove_tap(struct netlink_tap *nt) 211 { 212 struct net *net = dev_net(nt->dev); 213 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 214 bool found = false; 215 struct netlink_tap *tmp; 216 217 mutex_lock(&nn->netlink_tap_lock); 218 219 list_for_each_entry(tmp, &nn->netlink_tap_all, list) { 220 if (nt == tmp) { 221 list_del_rcu(&nt->list); 222 found = true; 223 goto out; 224 } 225 } 226 227 pr_warn("__netlink_remove_tap: %p not found\n", nt); 228 out: 229 mutex_unlock(&nn->netlink_tap_lock); 230 231 if (found) 232 module_put(nt->module); 233 234 return found ? 0 : -ENODEV; 235 } 236 237 int netlink_remove_tap(struct netlink_tap *nt) 238 { 239 int ret; 240 241 ret = __netlink_remove_tap(nt); 242 synchronize_net(); 243 244 return ret; 245 } 246 EXPORT_SYMBOL_GPL(netlink_remove_tap); 247 248 static __net_init int netlink_tap_init_net(struct net *net) 249 { 250 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 251 252 INIT_LIST_HEAD(&nn->netlink_tap_all); 253 mutex_init(&nn->netlink_tap_lock); 254 return 0; 255 } 256 257 static struct pernet_operations netlink_tap_net_ops = { 258 .init = netlink_tap_init_net, 259 .id = &netlink_tap_net_id, 260 .size = sizeof(struct netlink_tap_net), 261 }; 262 263 static bool netlink_filter_tap(const struct sk_buff *skb) 264 { 265 struct sock *sk = skb->sk; 266 267 /* We take the more conservative approach and 268 * whitelist socket protocols that may pass. 269 */ 270 switch (sk->sk_protocol) { 271 case NETLINK_ROUTE: 272 case NETLINK_USERSOCK: 273 case NETLINK_SOCK_DIAG: 274 case NETLINK_NFLOG: 275 case NETLINK_XFRM: 276 case NETLINK_FIB_LOOKUP: 277 case NETLINK_NETFILTER: 278 case NETLINK_GENERIC: 279 return true; 280 } 281 282 return false; 283 } 284 285 static int __netlink_deliver_tap_skb(struct sk_buff *skb, 286 struct net_device *dev) 287 { 288 struct sk_buff *nskb; 289 struct sock *sk = skb->sk; 290 int ret = -ENOMEM; 291 292 if (!net_eq(dev_net(dev), sock_net(sk))) 293 return 0; 294 295 dev_hold(dev); 296 297 if (is_vmalloc_addr(skb->head)) 298 nskb = netlink_to_full_skb(skb, GFP_ATOMIC); 299 else 300 nskb = skb_clone(skb, GFP_ATOMIC); 301 if (nskb) { 302 nskb->dev = dev; 303 nskb->protocol = htons((u16) sk->sk_protocol); 304 nskb->pkt_type = netlink_is_kernel(sk) ? 305 PACKET_KERNEL : PACKET_USER; 306 skb_reset_network_header(nskb); 307 ret = dev_queue_xmit(nskb); 308 if (unlikely(ret > 0)) 309 ret = net_xmit_errno(ret); 310 } 311 312 dev_put(dev); 313 return ret; 314 } 315 316 static void __netlink_deliver_tap(struct sk_buff *skb, struct netlink_tap_net *nn) 317 { 318 int ret; 319 struct netlink_tap *tmp; 320 321 if (!netlink_filter_tap(skb)) 322 return; 323 324 list_for_each_entry_rcu(tmp, &nn->netlink_tap_all, list) { 325 ret = __netlink_deliver_tap_skb(skb, tmp->dev); 326 if (unlikely(ret)) 327 break; 328 } 329 } 330 331 static void netlink_deliver_tap(struct net *net, struct sk_buff *skb) 332 { 333 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id); 334 335 rcu_read_lock(); 336 337 if (unlikely(!list_empty(&nn->netlink_tap_all))) 338 __netlink_deliver_tap(skb, nn); 339 340 rcu_read_unlock(); 341 } 342 343 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src, 344 struct sk_buff *skb) 345 { 346 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src))) 347 netlink_deliver_tap(sock_net(dst), skb); 348 } 349 350 static void netlink_overrun(struct sock *sk) 351 { 352 struct netlink_sock *nlk = nlk_sk(sk); 353 354 if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) { 355 if (!test_and_set_bit(NETLINK_S_CONGESTED, 356 &nlk_sk(sk)->state)) { 357 sk->sk_err = ENOBUFS; 358 sk_error_report(sk); 359 } 360 } 361 atomic_inc(&sk->sk_drops); 362 } 363 364 static void netlink_rcv_wake(struct sock *sk) 365 { 366 struct netlink_sock *nlk = nlk_sk(sk); 367 368 if (skb_queue_empty_lockless(&sk->sk_receive_queue)) 369 clear_bit(NETLINK_S_CONGESTED, &nlk->state); 370 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state)) 371 wake_up_interruptible(&nlk->wait); 372 } 373 374 static void netlink_skb_destructor(struct sk_buff *skb) 375 { 376 if (is_vmalloc_addr(skb->head)) { 377 if (!skb->cloned || 378 !atomic_dec_return(&(skb_shinfo(skb)->dataref))) 379 vfree(skb->head); 380 381 skb->head = NULL; 382 } 383 if (skb->sk != NULL) 384 sock_rfree(skb); 385 } 386 387 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk) 388 { 389 WARN_ON(skb->sk != NULL); 390 skb->sk = sk; 391 skb->destructor = netlink_skb_destructor; 392 atomic_add(skb->truesize, &sk->sk_rmem_alloc); 393 sk_mem_charge(sk, skb->truesize); 394 } 395 396 static void netlink_sock_destruct(struct sock *sk) 397 { 398 struct netlink_sock *nlk = nlk_sk(sk); 399 400 if (nlk->cb_running) { 401 if (nlk->cb.done) 402 nlk->cb.done(&nlk->cb); 403 module_put(nlk->cb.module); 404 kfree_skb(nlk->cb.skb); 405 } 406 407 skb_queue_purge(&sk->sk_receive_queue); 408 409 if (!sock_flag(sk, SOCK_DEAD)) { 410 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk); 411 return; 412 } 413 414 WARN_ON(atomic_read(&sk->sk_rmem_alloc)); 415 WARN_ON(refcount_read(&sk->sk_wmem_alloc)); 416 WARN_ON(nlk_sk(sk)->groups); 417 } 418 419 static void netlink_sock_destruct_work(struct work_struct *work) 420 { 421 struct netlink_sock *nlk = container_of(work, struct netlink_sock, 422 work); 423 424 sk_free(&nlk->sk); 425 } 426 427 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on 428 * SMP. Look, when several writers sleep and reader wakes them up, all but one 429 * immediately hit write lock and grab all the cpus. Exclusive sleep solves 430 * this, _but_ remember, it adds useless work on UP machines. 431 */ 432 433 void netlink_table_grab(void) 434 __acquires(nl_table_lock) 435 { 436 might_sleep(); 437 438 write_lock_irq(&nl_table_lock); 439 440 if (atomic_read(&nl_table_users)) { 441 DECLARE_WAITQUEUE(wait, current); 442 443 add_wait_queue_exclusive(&nl_table_wait, &wait); 444 for (;;) { 445 set_current_state(TASK_UNINTERRUPTIBLE); 446 if (atomic_read(&nl_table_users) == 0) 447 break; 448 write_unlock_irq(&nl_table_lock); 449 schedule(); 450 write_lock_irq(&nl_table_lock); 451 } 452 453 __set_current_state(TASK_RUNNING); 454 remove_wait_queue(&nl_table_wait, &wait); 455 } 456 } 457 458 void netlink_table_ungrab(void) 459 __releases(nl_table_lock) 460 { 461 write_unlock_irq(&nl_table_lock); 462 wake_up(&nl_table_wait); 463 } 464 465 static inline void 466 netlink_lock_table(void) 467 { 468 unsigned long flags; 469 470 /* read_lock() synchronizes us to netlink_table_grab */ 471 472 read_lock_irqsave(&nl_table_lock, flags); 473 atomic_inc(&nl_table_users); 474 read_unlock_irqrestore(&nl_table_lock, flags); 475 } 476 477 static inline void 478 netlink_unlock_table(void) 479 { 480 if (atomic_dec_and_test(&nl_table_users)) 481 wake_up(&nl_table_wait); 482 } 483 484 struct netlink_compare_arg 485 { 486 possible_net_t pnet; 487 u32 portid; 488 }; 489 490 /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */ 491 #define netlink_compare_arg_len \ 492 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32)) 493 494 static inline int netlink_compare(struct rhashtable_compare_arg *arg, 495 const void *ptr) 496 { 497 const struct netlink_compare_arg *x = arg->key; 498 const struct netlink_sock *nlk = ptr; 499 500 return nlk->portid != x->portid || 501 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet)); 502 } 503 504 static void netlink_compare_arg_init(struct netlink_compare_arg *arg, 505 struct net *net, u32 portid) 506 { 507 memset(arg, 0, sizeof(*arg)); 508 write_pnet(&arg->pnet, net); 509 arg->portid = portid; 510 } 511 512 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid, 513 struct net *net) 514 { 515 struct netlink_compare_arg arg; 516 517 netlink_compare_arg_init(&arg, net, portid); 518 return rhashtable_lookup_fast(&table->hash, &arg, 519 netlink_rhashtable_params); 520 } 521 522 static int __netlink_insert(struct netlink_table *table, struct sock *sk) 523 { 524 struct netlink_compare_arg arg; 525 526 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid); 527 return rhashtable_lookup_insert_key(&table->hash, &arg, 528 &nlk_sk(sk)->node, 529 netlink_rhashtable_params); 530 } 531 532 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid) 533 { 534 struct netlink_table *table = &nl_table[protocol]; 535 struct sock *sk; 536 537 rcu_read_lock(); 538 sk = __netlink_lookup(table, portid, net); 539 if (sk) 540 sock_hold(sk); 541 rcu_read_unlock(); 542 543 return sk; 544 } 545 546 static const struct proto_ops netlink_ops; 547 548 static void 549 netlink_update_listeners(struct sock *sk) 550 { 551 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 552 unsigned long mask; 553 unsigned int i; 554 struct listeners *listeners; 555 556 listeners = nl_deref_protected(tbl->listeners); 557 if (!listeners) 558 return; 559 560 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) { 561 mask = 0; 562 sk_for_each_bound(sk, &tbl->mc_list) { 563 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups)) 564 mask |= nlk_sk(sk)->groups[i]; 565 } 566 listeners->masks[i] = mask; 567 } 568 /* this function is only called with the netlink table "grabbed", which 569 * makes sure updates are visible before bind or setsockopt return. */ 570 } 571 572 static int netlink_insert(struct sock *sk, u32 portid) 573 { 574 struct netlink_table *table = &nl_table[sk->sk_protocol]; 575 int err; 576 577 lock_sock(sk); 578 579 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY; 580 if (nlk_sk(sk)->bound) 581 goto err; 582 583 /* portid can be read locklessly from netlink_getname(). */ 584 WRITE_ONCE(nlk_sk(sk)->portid, portid); 585 586 sock_hold(sk); 587 588 err = __netlink_insert(table, sk); 589 if (err) { 590 /* In case the hashtable backend returns with -EBUSY 591 * from here, it must not escape to the caller. 592 */ 593 if (unlikely(err == -EBUSY)) 594 err = -EOVERFLOW; 595 if (err == -EEXIST) 596 err = -EADDRINUSE; 597 sock_put(sk); 598 goto err; 599 } 600 601 /* We need to ensure that the socket is hashed and visible. */ 602 smp_wmb(); 603 /* Paired with lockless reads from netlink_bind(), 604 * netlink_connect() and netlink_sendmsg(). 605 */ 606 WRITE_ONCE(nlk_sk(sk)->bound, portid); 607 608 err: 609 release_sock(sk); 610 return err; 611 } 612 613 static void netlink_remove(struct sock *sk) 614 { 615 struct netlink_table *table; 616 617 table = &nl_table[sk->sk_protocol]; 618 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node, 619 netlink_rhashtable_params)) { 620 WARN_ON(refcount_read(&sk->sk_refcnt) == 1); 621 __sock_put(sk); 622 } 623 624 netlink_table_grab(); 625 if (nlk_sk(sk)->subscriptions) { 626 __sk_del_bind_node(sk); 627 netlink_update_listeners(sk); 628 } 629 if (sk->sk_protocol == NETLINK_GENERIC) 630 atomic_inc(&genl_sk_destructing_cnt); 631 netlink_table_ungrab(); 632 } 633 634 static struct proto netlink_proto = { 635 .name = "NETLINK", 636 .owner = THIS_MODULE, 637 .obj_size = sizeof(struct netlink_sock), 638 }; 639 640 static int __netlink_create(struct net *net, struct socket *sock, 641 struct mutex *cb_mutex, int protocol, 642 int kern) 643 { 644 struct sock *sk; 645 struct netlink_sock *nlk; 646 647 sock->ops = &netlink_ops; 648 649 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern); 650 if (!sk) 651 return -ENOMEM; 652 653 sock_init_data(sock, sk); 654 655 nlk = nlk_sk(sk); 656 if (cb_mutex) { 657 nlk->cb_mutex = cb_mutex; 658 } else { 659 nlk->cb_mutex = &nlk->cb_def_mutex; 660 mutex_init(nlk->cb_mutex); 661 lockdep_set_class_and_name(nlk->cb_mutex, 662 nlk_cb_mutex_keys + protocol, 663 nlk_cb_mutex_key_strings[protocol]); 664 } 665 init_waitqueue_head(&nlk->wait); 666 667 sk->sk_destruct = netlink_sock_destruct; 668 sk->sk_protocol = protocol; 669 return 0; 670 } 671 672 static int netlink_create(struct net *net, struct socket *sock, int protocol, 673 int kern) 674 { 675 struct module *module = NULL; 676 struct mutex *cb_mutex; 677 struct netlink_sock *nlk; 678 int (*bind)(struct net *net, int group); 679 void (*unbind)(struct net *net, int group); 680 int err = 0; 681 682 sock->state = SS_UNCONNECTED; 683 684 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) 685 return -ESOCKTNOSUPPORT; 686 687 if (protocol < 0 || protocol >= MAX_LINKS) 688 return -EPROTONOSUPPORT; 689 protocol = array_index_nospec(protocol, MAX_LINKS); 690 691 netlink_lock_table(); 692 #ifdef CONFIG_MODULES 693 if (!nl_table[protocol].registered) { 694 netlink_unlock_table(); 695 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); 696 netlink_lock_table(); 697 } 698 #endif 699 if (nl_table[protocol].registered && 700 try_module_get(nl_table[protocol].module)) 701 module = nl_table[protocol].module; 702 else 703 err = -EPROTONOSUPPORT; 704 cb_mutex = nl_table[protocol].cb_mutex; 705 bind = nl_table[protocol].bind; 706 unbind = nl_table[protocol].unbind; 707 netlink_unlock_table(); 708 709 if (err < 0) 710 goto out; 711 712 err = __netlink_create(net, sock, cb_mutex, protocol, kern); 713 if (err < 0) 714 goto out_module; 715 716 sock_prot_inuse_add(net, &netlink_proto, 1); 717 718 nlk = nlk_sk(sock->sk); 719 nlk->module = module; 720 nlk->netlink_bind = bind; 721 nlk->netlink_unbind = unbind; 722 out: 723 return err; 724 725 out_module: 726 module_put(module); 727 goto out; 728 } 729 730 static void deferred_put_nlk_sk(struct rcu_head *head) 731 { 732 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu); 733 struct sock *sk = &nlk->sk; 734 735 kfree(nlk->groups); 736 nlk->groups = NULL; 737 738 if (!refcount_dec_and_test(&sk->sk_refcnt)) 739 return; 740 741 if (nlk->cb_running && nlk->cb.done) { 742 INIT_WORK(&nlk->work, netlink_sock_destruct_work); 743 schedule_work(&nlk->work); 744 return; 745 } 746 747 sk_free(sk); 748 } 749 750 static int netlink_release(struct socket *sock) 751 { 752 struct sock *sk = sock->sk; 753 struct netlink_sock *nlk; 754 755 if (!sk) 756 return 0; 757 758 netlink_remove(sk); 759 sock_orphan(sk); 760 nlk = nlk_sk(sk); 761 762 /* 763 * OK. Socket is unlinked, any packets that arrive now 764 * will be purged. 765 */ 766 767 /* must not acquire netlink_table_lock in any way again before unbind 768 * and notifying genetlink is done as otherwise it might deadlock 769 */ 770 if (nlk->netlink_unbind) { 771 int i; 772 773 for (i = 0; i < nlk->ngroups; i++) 774 if (test_bit(i, nlk->groups)) 775 nlk->netlink_unbind(sock_net(sk), i + 1); 776 } 777 if (sk->sk_protocol == NETLINK_GENERIC && 778 atomic_dec_return(&genl_sk_destructing_cnt) == 0) 779 wake_up(&genl_sk_destructing_waitq); 780 781 sock->sk = NULL; 782 wake_up_interruptible_all(&nlk->wait); 783 784 skb_queue_purge(&sk->sk_write_queue); 785 786 if (nlk->portid && nlk->bound) { 787 struct netlink_notify n = { 788 .net = sock_net(sk), 789 .protocol = sk->sk_protocol, 790 .portid = nlk->portid, 791 }; 792 blocking_notifier_call_chain(&netlink_chain, 793 NETLINK_URELEASE, &n); 794 } 795 796 module_put(nlk->module); 797 798 if (netlink_is_kernel(sk)) { 799 netlink_table_grab(); 800 BUG_ON(nl_table[sk->sk_protocol].registered == 0); 801 if (--nl_table[sk->sk_protocol].registered == 0) { 802 struct listeners *old; 803 804 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners); 805 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL); 806 kfree_rcu(old, rcu); 807 nl_table[sk->sk_protocol].module = NULL; 808 nl_table[sk->sk_protocol].bind = NULL; 809 nl_table[sk->sk_protocol].unbind = NULL; 810 nl_table[sk->sk_protocol].flags = 0; 811 nl_table[sk->sk_protocol].registered = 0; 812 } 813 netlink_table_ungrab(); 814 } 815 816 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1); 817 818 /* Because struct net might disappear soon, do not keep a pointer. */ 819 if (!sk->sk_net_refcnt && sock_net(sk) != &init_net) { 820 __netns_tracker_free(sock_net(sk), &sk->ns_tracker, false); 821 /* Because of deferred_put_nlk_sk and use of work queue, 822 * it is possible netns will be freed before this socket. 823 */ 824 sock_net_set(sk, &init_net); 825 __netns_tracker_alloc(&init_net, &sk->ns_tracker, 826 false, GFP_KERNEL); 827 } 828 call_rcu(&nlk->rcu, deferred_put_nlk_sk); 829 return 0; 830 } 831 832 static int netlink_autobind(struct socket *sock) 833 { 834 struct sock *sk = sock->sk; 835 struct net *net = sock_net(sk); 836 struct netlink_table *table = &nl_table[sk->sk_protocol]; 837 s32 portid = task_tgid_vnr(current); 838 int err; 839 s32 rover = -4096; 840 bool ok; 841 842 retry: 843 cond_resched(); 844 rcu_read_lock(); 845 ok = !__netlink_lookup(table, portid, net); 846 rcu_read_unlock(); 847 if (!ok) { 848 /* Bind collision, search negative portid values. */ 849 if (rover == -4096) 850 /* rover will be in range [S32_MIN, -4097] */ 851 rover = S32_MIN + get_random_u32_below(-4096 - S32_MIN); 852 else if (rover >= -4096) 853 rover = -4097; 854 portid = rover--; 855 goto retry; 856 } 857 858 err = netlink_insert(sk, portid); 859 if (err == -EADDRINUSE) 860 goto retry; 861 862 /* If 2 threads race to autobind, that is fine. */ 863 if (err == -EBUSY) 864 err = 0; 865 866 return err; 867 } 868 869 /** 870 * __netlink_ns_capable - General netlink message capability test 871 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace. 872 * @user_ns: The user namespace of the capability to use 873 * @cap: The capability to use 874 * 875 * Test to see if the opener of the socket we received the message 876 * from had when the netlink socket was created and the sender of the 877 * message has the capability @cap in the user namespace @user_ns. 878 */ 879 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp, 880 struct user_namespace *user_ns, int cap) 881 { 882 return ((nsp->flags & NETLINK_SKB_DST) || 883 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) && 884 ns_capable(user_ns, cap); 885 } 886 EXPORT_SYMBOL(__netlink_ns_capable); 887 888 /** 889 * netlink_ns_capable - General netlink message capability test 890 * @skb: socket buffer holding a netlink command from userspace 891 * @user_ns: The user namespace of the capability to use 892 * @cap: The capability to use 893 * 894 * Test to see if the opener of the socket we received the message 895 * from had when the netlink socket was created and the sender of the 896 * message has the capability @cap in the user namespace @user_ns. 897 */ 898 bool netlink_ns_capable(const struct sk_buff *skb, 899 struct user_namespace *user_ns, int cap) 900 { 901 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap); 902 } 903 EXPORT_SYMBOL(netlink_ns_capable); 904 905 /** 906 * netlink_capable - Netlink global 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 the capability @cap in all user namespaces. 913 */ 914 bool netlink_capable(const struct sk_buff *skb, int cap) 915 { 916 return netlink_ns_capable(skb, &init_user_ns, cap); 917 } 918 EXPORT_SYMBOL(netlink_capable); 919 920 /** 921 * netlink_net_capable - Netlink network namespace message capability test 922 * @skb: socket buffer holding a netlink command from userspace 923 * @cap: The capability to use 924 * 925 * Test to see if the opener of the socket we received the message 926 * from had when the netlink socket was created and the sender of the 927 * message has the capability @cap over the network namespace of 928 * the socket we received the message from. 929 */ 930 bool netlink_net_capable(const struct sk_buff *skb, int cap) 931 { 932 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap); 933 } 934 EXPORT_SYMBOL(netlink_net_capable); 935 936 static inline int netlink_allowed(const struct socket *sock, unsigned int flag) 937 { 938 return (nl_table[sock->sk->sk_protocol].flags & flag) || 939 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN); 940 } 941 942 static void 943 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) 944 { 945 struct netlink_sock *nlk = nlk_sk(sk); 946 947 if (nlk->subscriptions && !subscriptions) 948 __sk_del_bind_node(sk); 949 else if (!nlk->subscriptions && subscriptions) 950 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); 951 nlk->subscriptions = subscriptions; 952 } 953 954 static int netlink_realloc_groups(struct sock *sk) 955 { 956 struct netlink_sock *nlk = nlk_sk(sk); 957 unsigned int groups; 958 unsigned long *new_groups; 959 int err = 0; 960 961 netlink_table_grab(); 962 963 groups = nl_table[sk->sk_protocol].groups; 964 if (!nl_table[sk->sk_protocol].registered) { 965 err = -ENOENT; 966 goto out_unlock; 967 } 968 969 if (nlk->ngroups >= groups) 970 goto out_unlock; 971 972 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC); 973 if (new_groups == NULL) { 974 err = -ENOMEM; 975 goto out_unlock; 976 } 977 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0, 978 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups)); 979 980 nlk->groups = new_groups; 981 nlk->ngroups = groups; 982 out_unlock: 983 netlink_table_ungrab(); 984 return err; 985 } 986 987 static void netlink_undo_bind(int group, long unsigned int groups, 988 struct sock *sk) 989 { 990 struct netlink_sock *nlk = nlk_sk(sk); 991 int undo; 992 993 if (!nlk->netlink_unbind) 994 return; 995 996 for (undo = 0; undo < group; undo++) 997 if (test_bit(undo, &groups)) 998 nlk->netlink_unbind(sock_net(sk), undo + 1); 999 } 1000 1001 static int netlink_bind(struct socket *sock, struct sockaddr *addr, 1002 int addr_len) 1003 { 1004 struct sock *sk = sock->sk; 1005 struct net *net = sock_net(sk); 1006 struct netlink_sock *nlk = nlk_sk(sk); 1007 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 1008 int err = 0; 1009 unsigned long groups; 1010 bool bound; 1011 1012 if (addr_len < sizeof(struct sockaddr_nl)) 1013 return -EINVAL; 1014 1015 if (nladdr->nl_family != AF_NETLINK) 1016 return -EINVAL; 1017 groups = nladdr->nl_groups; 1018 1019 /* Only superuser is allowed to listen multicasts */ 1020 if (groups) { 1021 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) 1022 return -EPERM; 1023 err = netlink_realloc_groups(sk); 1024 if (err) 1025 return err; 1026 } 1027 1028 if (nlk->ngroups < BITS_PER_LONG) 1029 groups &= (1UL << nlk->ngroups) - 1; 1030 1031 /* Paired with WRITE_ONCE() in netlink_insert() */ 1032 bound = READ_ONCE(nlk->bound); 1033 if (bound) { 1034 /* Ensure nlk->portid is up-to-date. */ 1035 smp_rmb(); 1036 1037 if (nladdr->nl_pid != nlk->portid) 1038 return -EINVAL; 1039 } 1040 1041 if (nlk->netlink_bind && groups) { 1042 int group; 1043 1044 /* nl_groups is a u32, so cap the maximum groups we can bind */ 1045 for (group = 0; group < BITS_PER_TYPE(u32); group++) { 1046 if (!test_bit(group, &groups)) 1047 continue; 1048 err = nlk->netlink_bind(net, group + 1); 1049 if (!err) 1050 continue; 1051 netlink_undo_bind(group, groups, sk); 1052 return err; 1053 } 1054 } 1055 1056 /* No need for barriers here as we return to user-space without 1057 * using any of the bound attributes. 1058 */ 1059 netlink_lock_table(); 1060 if (!bound) { 1061 err = nladdr->nl_pid ? 1062 netlink_insert(sk, nladdr->nl_pid) : 1063 netlink_autobind(sock); 1064 if (err) { 1065 netlink_undo_bind(BITS_PER_TYPE(u32), groups, sk); 1066 goto unlock; 1067 } 1068 } 1069 1070 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) 1071 goto unlock; 1072 netlink_unlock_table(); 1073 1074 netlink_table_grab(); 1075 netlink_update_subscriptions(sk, nlk->subscriptions + 1076 hweight32(groups) - 1077 hweight32(nlk->groups[0])); 1078 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups; 1079 netlink_update_listeners(sk); 1080 netlink_table_ungrab(); 1081 1082 return 0; 1083 1084 unlock: 1085 netlink_unlock_table(); 1086 return err; 1087 } 1088 1089 static int netlink_connect(struct socket *sock, struct sockaddr *addr, 1090 int alen, int flags) 1091 { 1092 int err = 0; 1093 struct sock *sk = sock->sk; 1094 struct netlink_sock *nlk = nlk_sk(sk); 1095 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 1096 1097 if (alen < sizeof(addr->sa_family)) 1098 return -EINVAL; 1099 1100 if (addr->sa_family == AF_UNSPEC) { 1101 /* paired with READ_ONCE() in netlink_getsockbyportid() */ 1102 WRITE_ONCE(sk->sk_state, NETLINK_UNCONNECTED); 1103 /* dst_portid and dst_group can be read locklessly */ 1104 WRITE_ONCE(nlk->dst_portid, 0); 1105 WRITE_ONCE(nlk->dst_group, 0); 1106 return 0; 1107 } 1108 if (addr->sa_family != AF_NETLINK) 1109 return -EINVAL; 1110 1111 if (alen < sizeof(struct sockaddr_nl)) 1112 return -EINVAL; 1113 1114 if ((nladdr->nl_groups || nladdr->nl_pid) && 1115 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) 1116 return -EPERM; 1117 1118 /* No need for barriers here as we return to user-space without 1119 * using any of the bound attributes. 1120 * Paired with WRITE_ONCE() in netlink_insert(). 1121 */ 1122 if (!READ_ONCE(nlk->bound)) 1123 err = netlink_autobind(sock); 1124 1125 if (err == 0) { 1126 /* paired with READ_ONCE() in netlink_getsockbyportid() */ 1127 WRITE_ONCE(sk->sk_state, NETLINK_CONNECTED); 1128 /* dst_portid and dst_group can be read locklessly */ 1129 WRITE_ONCE(nlk->dst_portid, nladdr->nl_pid); 1130 WRITE_ONCE(nlk->dst_group, ffs(nladdr->nl_groups)); 1131 } 1132 1133 return err; 1134 } 1135 1136 static int netlink_getname(struct socket *sock, struct sockaddr *addr, 1137 int peer) 1138 { 1139 struct sock *sk = sock->sk; 1140 struct netlink_sock *nlk = nlk_sk(sk); 1141 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr); 1142 1143 nladdr->nl_family = AF_NETLINK; 1144 nladdr->nl_pad = 0; 1145 1146 if (peer) { 1147 /* Paired with WRITE_ONCE() in netlink_connect() */ 1148 nladdr->nl_pid = READ_ONCE(nlk->dst_portid); 1149 nladdr->nl_groups = netlink_group_mask(READ_ONCE(nlk->dst_group)); 1150 } else { 1151 /* Paired with WRITE_ONCE() in netlink_insert() */ 1152 nladdr->nl_pid = READ_ONCE(nlk->portid); 1153 netlink_lock_table(); 1154 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; 1155 netlink_unlock_table(); 1156 } 1157 return sizeof(*nladdr); 1158 } 1159 1160 static int netlink_ioctl(struct socket *sock, unsigned int cmd, 1161 unsigned long arg) 1162 { 1163 /* try to hand this ioctl down to the NIC drivers. 1164 */ 1165 return -ENOIOCTLCMD; 1166 } 1167 1168 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid) 1169 { 1170 struct sock *sock; 1171 struct netlink_sock *nlk; 1172 1173 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid); 1174 if (!sock) 1175 return ERR_PTR(-ECONNREFUSED); 1176 1177 /* Don't bother queuing skb if kernel socket has no input function */ 1178 nlk = nlk_sk(sock); 1179 /* dst_portid and sk_state can be changed in netlink_connect() */ 1180 if (READ_ONCE(sock->sk_state) == NETLINK_CONNECTED && 1181 READ_ONCE(nlk->dst_portid) != nlk_sk(ssk)->portid) { 1182 sock_put(sock); 1183 return ERR_PTR(-ECONNREFUSED); 1184 } 1185 return sock; 1186 } 1187 1188 struct sock *netlink_getsockbyfilp(struct file *filp) 1189 { 1190 struct inode *inode = file_inode(filp); 1191 struct sock *sock; 1192 1193 if (!S_ISSOCK(inode->i_mode)) 1194 return ERR_PTR(-ENOTSOCK); 1195 1196 sock = SOCKET_I(inode)->sk; 1197 if (sock->sk_family != AF_NETLINK) 1198 return ERR_PTR(-EINVAL); 1199 1200 sock_hold(sock); 1201 return sock; 1202 } 1203 1204 static struct sk_buff *netlink_alloc_large_skb(unsigned int size, 1205 int broadcast) 1206 { 1207 struct sk_buff *skb; 1208 void *data; 1209 1210 if (size <= NLMSG_GOODSIZE || broadcast) 1211 return alloc_skb(size, GFP_KERNEL); 1212 1213 size = SKB_DATA_ALIGN(size) + 1214 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 1215 1216 data = vmalloc(size); 1217 if (data == NULL) 1218 return NULL; 1219 1220 skb = __build_skb(data, size); 1221 if (skb == NULL) 1222 vfree(data); 1223 else 1224 skb->destructor = netlink_skb_destructor; 1225 1226 return skb; 1227 } 1228 1229 /* 1230 * Attach a skb to a netlink socket. 1231 * The caller must hold a reference to the destination socket. On error, the 1232 * reference is dropped. The skb is not send to the destination, just all 1233 * all error checks are performed and memory in the queue is reserved. 1234 * Return values: 1235 * < 0: error. skb freed, reference to sock dropped. 1236 * 0: continue 1237 * 1: repeat lookup - reference dropped while waiting for socket memory. 1238 */ 1239 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, 1240 long *timeo, struct sock *ssk) 1241 { 1242 struct netlink_sock *nlk; 1243 1244 nlk = nlk_sk(sk); 1245 1246 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 1247 test_bit(NETLINK_S_CONGESTED, &nlk->state))) { 1248 DECLARE_WAITQUEUE(wait, current); 1249 if (!*timeo) { 1250 if (!ssk || netlink_is_kernel(ssk)) 1251 netlink_overrun(sk); 1252 sock_put(sk); 1253 kfree_skb(skb); 1254 return -EAGAIN; 1255 } 1256 1257 __set_current_state(TASK_INTERRUPTIBLE); 1258 add_wait_queue(&nlk->wait, &wait); 1259 1260 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 1261 test_bit(NETLINK_S_CONGESTED, &nlk->state)) && 1262 !sock_flag(sk, SOCK_DEAD)) 1263 *timeo = schedule_timeout(*timeo); 1264 1265 __set_current_state(TASK_RUNNING); 1266 remove_wait_queue(&nlk->wait, &wait); 1267 sock_put(sk); 1268 1269 if (signal_pending(current)) { 1270 kfree_skb(skb); 1271 return sock_intr_errno(*timeo); 1272 } 1273 return 1; 1274 } 1275 netlink_skb_set_owner_r(skb, sk); 1276 return 0; 1277 } 1278 1279 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb) 1280 { 1281 int len = skb->len; 1282 1283 netlink_deliver_tap(sock_net(sk), skb); 1284 1285 skb_queue_tail(&sk->sk_receive_queue, skb); 1286 sk->sk_data_ready(sk); 1287 return len; 1288 } 1289 1290 int netlink_sendskb(struct sock *sk, struct sk_buff *skb) 1291 { 1292 int len = __netlink_sendskb(sk, skb); 1293 1294 sock_put(sk); 1295 return len; 1296 } 1297 1298 void netlink_detachskb(struct sock *sk, struct sk_buff *skb) 1299 { 1300 kfree_skb(skb); 1301 sock_put(sk); 1302 } 1303 1304 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation) 1305 { 1306 int delta; 1307 1308 WARN_ON(skb->sk != NULL); 1309 delta = skb->end - skb->tail; 1310 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize) 1311 return skb; 1312 1313 if (skb_shared(skb)) { 1314 struct sk_buff *nskb = skb_clone(skb, allocation); 1315 if (!nskb) 1316 return skb; 1317 consume_skb(skb); 1318 skb = nskb; 1319 } 1320 1321 pskb_expand_head(skb, 0, -delta, 1322 (allocation & ~__GFP_DIRECT_RECLAIM) | 1323 __GFP_NOWARN | __GFP_NORETRY); 1324 return skb; 1325 } 1326 1327 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb, 1328 struct sock *ssk) 1329 { 1330 int ret; 1331 struct netlink_sock *nlk = nlk_sk(sk); 1332 1333 ret = -ECONNREFUSED; 1334 if (nlk->netlink_rcv != NULL) { 1335 ret = skb->len; 1336 netlink_skb_set_owner_r(skb, sk); 1337 NETLINK_CB(skb).sk = ssk; 1338 netlink_deliver_tap_kernel(sk, ssk, skb); 1339 nlk->netlink_rcv(skb); 1340 consume_skb(skb); 1341 } else { 1342 kfree_skb(skb); 1343 } 1344 sock_put(sk); 1345 return ret; 1346 } 1347 1348 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, 1349 u32 portid, int nonblock) 1350 { 1351 struct sock *sk; 1352 int err; 1353 long timeo; 1354 1355 skb = netlink_trim(skb, gfp_any()); 1356 1357 timeo = sock_sndtimeo(ssk, nonblock); 1358 retry: 1359 sk = netlink_getsockbyportid(ssk, portid); 1360 if (IS_ERR(sk)) { 1361 kfree_skb(skb); 1362 return PTR_ERR(sk); 1363 } 1364 if (netlink_is_kernel(sk)) 1365 return netlink_unicast_kernel(sk, skb, ssk); 1366 1367 if (sk_filter(sk, skb)) { 1368 err = skb->len; 1369 kfree_skb(skb); 1370 sock_put(sk); 1371 return err; 1372 } 1373 1374 err = netlink_attachskb(sk, skb, &timeo, ssk); 1375 if (err == 1) 1376 goto retry; 1377 if (err) 1378 return err; 1379 1380 return netlink_sendskb(sk, skb); 1381 } 1382 EXPORT_SYMBOL(netlink_unicast); 1383 1384 int netlink_has_listeners(struct sock *sk, unsigned int group) 1385 { 1386 int res = 0; 1387 struct listeners *listeners; 1388 1389 BUG_ON(!netlink_is_kernel(sk)); 1390 1391 rcu_read_lock(); 1392 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners); 1393 1394 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups) 1395 res = test_bit(group - 1, listeners->masks); 1396 1397 rcu_read_unlock(); 1398 1399 return res; 1400 } 1401 EXPORT_SYMBOL_GPL(netlink_has_listeners); 1402 1403 bool netlink_strict_get_check(struct sk_buff *skb) 1404 { 1405 const struct netlink_sock *nlk = nlk_sk(NETLINK_CB(skb).sk); 1406 1407 return nlk->flags & NETLINK_F_STRICT_CHK; 1408 } 1409 EXPORT_SYMBOL_GPL(netlink_strict_get_check); 1410 1411 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) 1412 { 1413 struct netlink_sock *nlk = nlk_sk(sk); 1414 1415 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && 1416 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) { 1417 netlink_skb_set_owner_r(skb, sk); 1418 __netlink_sendskb(sk, skb); 1419 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1); 1420 } 1421 return -1; 1422 } 1423 1424 struct netlink_broadcast_data { 1425 struct sock *exclude_sk; 1426 struct net *net; 1427 u32 portid; 1428 u32 group; 1429 int failure; 1430 int delivery_failure; 1431 int congested; 1432 int delivered; 1433 gfp_t allocation; 1434 struct sk_buff *skb, *skb2; 1435 }; 1436 1437 static void do_one_broadcast(struct sock *sk, 1438 struct netlink_broadcast_data *p) 1439 { 1440 struct netlink_sock *nlk = nlk_sk(sk); 1441 int val; 1442 1443 if (p->exclude_sk == sk) 1444 return; 1445 1446 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups || 1447 !test_bit(p->group - 1, nlk->groups)) 1448 return; 1449 1450 if (!net_eq(sock_net(sk), p->net)) { 1451 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID)) 1452 return; 1453 1454 if (!peernet_has_id(sock_net(sk), p->net)) 1455 return; 1456 1457 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns, 1458 CAP_NET_BROADCAST)) 1459 return; 1460 } 1461 1462 if (p->failure) { 1463 netlink_overrun(sk); 1464 return; 1465 } 1466 1467 sock_hold(sk); 1468 if (p->skb2 == NULL) { 1469 if (skb_shared(p->skb)) { 1470 p->skb2 = skb_clone(p->skb, p->allocation); 1471 } else { 1472 p->skb2 = skb_get(p->skb); 1473 /* 1474 * skb ownership may have been set when 1475 * delivered to a previous socket. 1476 */ 1477 skb_orphan(p->skb2); 1478 } 1479 } 1480 if (p->skb2 == NULL) { 1481 netlink_overrun(sk); 1482 /* Clone failed. Notify ALL listeners. */ 1483 p->failure = 1; 1484 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR) 1485 p->delivery_failure = 1; 1486 goto out; 1487 } 1488 if (sk_filter(sk, p->skb2)) { 1489 kfree_skb(p->skb2); 1490 p->skb2 = NULL; 1491 goto out; 1492 } 1493 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net); 1494 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED) 1495 NETLINK_CB(p->skb2).nsid_is_set = true; 1496 val = netlink_broadcast_deliver(sk, p->skb2); 1497 if (val < 0) { 1498 netlink_overrun(sk); 1499 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR) 1500 p->delivery_failure = 1; 1501 } else { 1502 p->congested |= val; 1503 p->delivered = 1; 1504 p->skb2 = NULL; 1505 } 1506 out: 1507 sock_put(sk); 1508 } 1509 1510 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid, 1511 u32 group, gfp_t allocation) 1512 { 1513 struct net *net = sock_net(ssk); 1514 struct netlink_broadcast_data info; 1515 struct sock *sk; 1516 1517 skb = netlink_trim(skb, allocation); 1518 1519 info.exclude_sk = ssk; 1520 info.net = net; 1521 info.portid = portid; 1522 info.group = group; 1523 info.failure = 0; 1524 info.delivery_failure = 0; 1525 info.congested = 0; 1526 info.delivered = 0; 1527 info.allocation = allocation; 1528 info.skb = skb; 1529 info.skb2 = NULL; 1530 1531 /* While we sleep in clone, do not allow to change socket list */ 1532 1533 netlink_lock_table(); 1534 1535 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) 1536 do_one_broadcast(sk, &info); 1537 1538 consume_skb(skb); 1539 1540 netlink_unlock_table(); 1541 1542 if (info.delivery_failure) { 1543 kfree_skb(info.skb2); 1544 return -ENOBUFS; 1545 } 1546 consume_skb(info.skb2); 1547 1548 if (info.delivered) { 1549 if (info.congested && gfpflags_allow_blocking(allocation)) 1550 yield(); 1551 return 0; 1552 } 1553 return -ESRCH; 1554 } 1555 EXPORT_SYMBOL(netlink_broadcast); 1556 1557 struct netlink_set_err_data { 1558 struct sock *exclude_sk; 1559 u32 portid; 1560 u32 group; 1561 int code; 1562 }; 1563 1564 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p) 1565 { 1566 struct netlink_sock *nlk = nlk_sk(sk); 1567 int ret = 0; 1568 1569 if (sk == p->exclude_sk) 1570 goto out; 1571 1572 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk))) 1573 goto out; 1574 1575 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups || 1576 !test_bit(p->group - 1, nlk->groups)) 1577 goto out; 1578 1579 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) { 1580 ret = 1; 1581 goto out; 1582 } 1583 1584 sk->sk_err = p->code; 1585 sk_error_report(sk); 1586 out: 1587 return ret; 1588 } 1589 1590 /** 1591 * netlink_set_err - report error to broadcast listeners 1592 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create() 1593 * @portid: the PORTID of a process that we want to skip (if any) 1594 * @group: the broadcast group that will notice the error 1595 * @code: error code, must be negative (as usual in kernelspace) 1596 * 1597 * This function returns the number of broadcast listeners that have set the 1598 * NETLINK_NO_ENOBUFS socket option. 1599 */ 1600 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code) 1601 { 1602 struct netlink_set_err_data info; 1603 struct sock *sk; 1604 int ret = 0; 1605 1606 info.exclude_sk = ssk; 1607 info.portid = portid; 1608 info.group = group; 1609 /* sk->sk_err wants a positive error value */ 1610 info.code = -code; 1611 1612 read_lock(&nl_table_lock); 1613 1614 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) 1615 ret += do_one_set_err(sk, &info); 1616 1617 read_unlock(&nl_table_lock); 1618 return ret; 1619 } 1620 EXPORT_SYMBOL(netlink_set_err); 1621 1622 /* must be called with netlink table grabbed */ 1623 static void netlink_update_socket_mc(struct netlink_sock *nlk, 1624 unsigned int group, 1625 int is_new) 1626 { 1627 int old, new = !!is_new, subscriptions; 1628 1629 old = test_bit(group - 1, nlk->groups); 1630 subscriptions = nlk->subscriptions - old + new; 1631 if (new) 1632 __set_bit(group - 1, nlk->groups); 1633 else 1634 __clear_bit(group - 1, nlk->groups); 1635 netlink_update_subscriptions(&nlk->sk, subscriptions); 1636 netlink_update_listeners(&nlk->sk); 1637 } 1638 1639 static int netlink_setsockopt(struct socket *sock, int level, int optname, 1640 sockptr_t optval, unsigned int optlen) 1641 { 1642 struct sock *sk = sock->sk; 1643 struct netlink_sock *nlk = nlk_sk(sk); 1644 unsigned int val = 0; 1645 int err; 1646 1647 if (level != SOL_NETLINK) 1648 return -ENOPROTOOPT; 1649 1650 if (optlen >= sizeof(int) && 1651 copy_from_sockptr(&val, optval, sizeof(val))) 1652 return -EFAULT; 1653 1654 switch (optname) { 1655 case NETLINK_PKTINFO: 1656 if (val) 1657 nlk->flags |= NETLINK_F_RECV_PKTINFO; 1658 else 1659 nlk->flags &= ~NETLINK_F_RECV_PKTINFO; 1660 err = 0; 1661 break; 1662 case NETLINK_ADD_MEMBERSHIP: 1663 case NETLINK_DROP_MEMBERSHIP: { 1664 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) 1665 return -EPERM; 1666 err = netlink_realloc_groups(sk); 1667 if (err) 1668 return err; 1669 if (!val || val - 1 >= nlk->ngroups) 1670 return -EINVAL; 1671 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) { 1672 err = nlk->netlink_bind(sock_net(sk), val); 1673 if (err) 1674 return err; 1675 } 1676 netlink_table_grab(); 1677 netlink_update_socket_mc(nlk, val, 1678 optname == NETLINK_ADD_MEMBERSHIP); 1679 netlink_table_ungrab(); 1680 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind) 1681 nlk->netlink_unbind(sock_net(sk), val); 1682 1683 err = 0; 1684 break; 1685 } 1686 case NETLINK_BROADCAST_ERROR: 1687 if (val) 1688 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR; 1689 else 1690 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR; 1691 err = 0; 1692 break; 1693 case NETLINK_NO_ENOBUFS: 1694 if (val) { 1695 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS; 1696 clear_bit(NETLINK_S_CONGESTED, &nlk->state); 1697 wake_up_interruptible(&nlk->wait); 1698 } else { 1699 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS; 1700 } 1701 err = 0; 1702 break; 1703 case NETLINK_LISTEN_ALL_NSID: 1704 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST)) 1705 return -EPERM; 1706 1707 if (val) 1708 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID; 1709 else 1710 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID; 1711 err = 0; 1712 break; 1713 case NETLINK_CAP_ACK: 1714 if (val) 1715 nlk->flags |= NETLINK_F_CAP_ACK; 1716 else 1717 nlk->flags &= ~NETLINK_F_CAP_ACK; 1718 err = 0; 1719 break; 1720 case NETLINK_EXT_ACK: 1721 if (val) 1722 nlk->flags |= NETLINK_F_EXT_ACK; 1723 else 1724 nlk->flags &= ~NETLINK_F_EXT_ACK; 1725 err = 0; 1726 break; 1727 case NETLINK_GET_STRICT_CHK: 1728 if (val) 1729 nlk->flags |= NETLINK_F_STRICT_CHK; 1730 else 1731 nlk->flags &= ~NETLINK_F_STRICT_CHK; 1732 err = 0; 1733 break; 1734 default: 1735 err = -ENOPROTOOPT; 1736 } 1737 return err; 1738 } 1739 1740 static int netlink_getsockopt(struct socket *sock, int level, int optname, 1741 char __user *optval, int __user *optlen) 1742 { 1743 struct sock *sk = sock->sk; 1744 struct netlink_sock *nlk = nlk_sk(sk); 1745 unsigned int flag; 1746 int len, val; 1747 1748 if (level != SOL_NETLINK) 1749 return -ENOPROTOOPT; 1750 1751 if (get_user(len, optlen)) 1752 return -EFAULT; 1753 if (len < 0) 1754 return -EINVAL; 1755 1756 switch (optname) { 1757 case NETLINK_PKTINFO: 1758 flag = NETLINK_F_RECV_PKTINFO; 1759 break; 1760 case NETLINK_BROADCAST_ERROR: 1761 flag = NETLINK_F_BROADCAST_SEND_ERROR; 1762 break; 1763 case NETLINK_NO_ENOBUFS: 1764 flag = NETLINK_F_RECV_NO_ENOBUFS; 1765 break; 1766 case NETLINK_LIST_MEMBERSHIPS: { 1767 int pos, idx, shift, err = 0; 1768 1769 netlink_lock_table(); 1770 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) { 1771 if (len - pos < sizeof(u32)) 1772 break; 1773 1774 idx = pos / sizeof(unsigned long); 1775 shift = (pos % sizeof(unsigned long)) * 8; 1776 if (put_user((u32)(nlk->groups[idx] >> shift), 1777 (u32 __user *)(optval + pos))) { 1778 err = -EFAULT; 1779 break; 1780 } 1781 } 1782 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen)) 1783 err = -EFAULT; 1784 netlink_unlock_table(); 1785 return err; 1786 } 1787 case NETLINK_CAP_ACK: 1788 flag = NETLINK_F_CAP_ACK; 1789 break; 1790 case NETLINK_EXT_ACK: 1791 flag = NETLINK_F_EXT_ACK; 1792 break; 1793 case NETLINK_GET_STRICT_CHK: 1794 flag = NETLINK_F_STRICT_CHK; 1795 break; 1796 default: 1797 return -ENOPROTOOPT; 1798 } 1799 1800 if (len < sizeof(int)) 1801 return -EINVAL; 1802 1803 len = sizeof(int); 1804 val = nlk->flags & flag ? 1 : 0; 1805 1806 if (put_user(len, optlen) || 1807 copy_to_user(optval, &val, len)) 1808 return -EFAULT; 1809 1810 return 0; 1811 } 1812 1813 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) 1814 { 1815 struct nl_pktinfo info; 1816 1817 info.group = NETLINK_CB(skb).dst_group; 1818 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); 1819 } 1820 1821 static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg, 1822 struct sk_buff *skb) 1823 { 1824 if (!NETLINK_CB(skb).nsid_is_set) 1825 return; 1826 1827 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int), 1828 &NETLINK_CB(skb).nsid); 1829 } 1830 1831 static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 1832 { 1833 struct sock *sk = sock->sk; 1834 struct netlink_sock *nlk = nlk_sk(sk); 1835 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); 1836 u32 dst_portid; 1837 u32 dst_group; 1838 struct sk_buff *skb; 1839 int err; 1840 struct scm_cookie scm; 1841 u32 netlink_skb_flags = 0; 1842 1843 if (msg->msg_flags & MSG_OOB) 1844 return -EOPNOTSUPP; 1845 1846 if (len == 0) { 1847 pr_warn_once("Zero length message leads to an empty skb\n"); 1848 return -ENODATA; 1849 } 1850 1851 err = scm_send(sock, msg, &scm, true); 1852 if (err < 0) 1853 return err; 1854 1855 if (msg->msg_namelen) { 1856 err = -EINVAL; 1857 if (msg->msg_namelen < sizeof(struct sockaddr_nl)) 1858 goto out; 1859 if (addr->nl_family != AF_NETLINK) 1860 goto out; 1861 dst_portid = addr->nl_pid; 1862 dst_group = ffs(addr->nl_groups); 1863 err = -EPERM; 1864 if ((dst_group || dst_portid) && 1865 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) 1866 goto out; 1867 netlink_skb_flags |= NETLINK_SKB_DST; 1868 } else { 1869 /* Paired with WRITE_ONCE() in netlink_connect() */ 1870 dst_portid = READ_ONCE(nlk->dst_portid); 1871 dst_group = READ_ONCE(nlk->dst_group); 1872 } 1873 1874 /* Paired with WRITE_ONCE() in netlink_insert() */ 1875 if (!READ_ONCE(nlk->bound)) { 1876 err = netlink_autobind(sock); 1877 if (err) 1878 goto out; 1879 } else { 1880 /* Ensure nlk is hashed and visible. */ 1881 smp_rmb(); 1882 } 1883 1884 err = -EMSGSIZE; 1885 if (len > sk->sk_sndbuf - 32) 1886 goto out; 1887 err = -ENOBUFS; 1888 skb = netlink_alloc_large_skb(len, dst_group); 1889 if (skb == NULL) 1890 goto out; 1891 1892 NETLINK_CB(skb).portid = nlk->portid; 1893 NETLINK_CB(skb).dst_group = dst_group; 1894 NETLINK_CB(skb).creds = scm.creds; 1895 NETLINK_CB(skb).flags = netlink_skb_flags; 1896 1897 err = -EFAULT; 1898 if (memcpy_from_msg(skb_put(skb, len), msg, len)) { 1899 kfree_skb(skb); 1900 goto out; 1901 } 1902 1903 err = security_netlink_send(sk, skb); 1904 if (err) { 1905 kfree_skb(skb); 1906 goto out; 1907 } 1908 1909 if (dst_group) { 1910 refcount_inc(&skb->users); 1911 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL); 1912 } 1913 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags & MSG_DONTWAIT); 1914 1915 out: 1916 scm_destroy(&scm); 1917 return err; 1918 } 1919 1920 static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 1921 int flags) 1922 { 1923 struct scm_cookie scm; 1924 struct sock *sk = sock->sk; 1925 struct netlink_sock *nlk = nlk_sk(sk); 1926 size_t copied, max_recvmsg_len; 1927 struct sk_buff *skb, *data_skb; 1928 int err, ret; 1929 1930 if (flags & MSG_OOB) 1931 return -EOPNOTSUPP; 1932 1933 copied = 0; 1934 1935 skb = skb_recv_datagram(sk, flags, &err); 1936 if (skb == NULL) 1937 goto out; 1938 1939 data_skb = skb; 1940 1941 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES 1942 if (unlikely(skb_shinfo(skb)->frag_list)) { 1943 /* 1944 * If this skb has a frag_list, then here that means that we 1945 * will have to use the frag_list skb's data for compat tasks 1946 * and the regular skb's data for normal (non-compat) tasks. 1947 * 1948 * If we need to send the compat skb, assign it to the 1949 * 'data_skb' variable so that it will be used below for data 1950 * copying. We keep 'skb' for everything else, including 1951 * freeing both later. 1952 */ 1953 if (flags & MSG_CMSG_COMPAT) 1954 data_skb = skb_shinfo(skb)->frag_list; 1955 } 1956 #endif 1957 1958 /* Record the max length of recvmsg() calls for future allocations */ 1959 max_recvmsg_len = max(READ_ONCE(nlk->max_recvmsg_len), len); 1960 max_recvmsg_len = min_t(size_t, max_recvmsg_len, 1961 SKB_WITH_OVERHEAD(32768)); 1962 WRITE_ONCE(nlk->max_recvmsg_len, max_recvmsg_len); 1963 1964 copied = data_skb->len; 1965 if (len < copied) { 1966 msg->msg_flags |= MSG_TRUNC; 1967 copied = len; 1968 } 1969 1970 err = skb_copy_datagram_msg(data_skb, 0, msg, copied); 1971 1972 if (msg->msg_name) { 1973 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); 1974 addr->nl_family = AF_NETLINK; 1975 addr->nl_pad = 0; 1976 addr->nl_pid = NETLINK_CB(skb).portid; 1977 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); 1978 msg->msg_namelen = sizeof(*addr); 1979 } 1980 1981 if (nlk->flags & NETLINK_F_RECV_PKTINFO) 1982 netlink_cmsg_recv_pktinfo(msg, skb); 1983 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID) 1984 netlink_cmsg_listen_all_nsid(sk, msg, skb); 1985 1986 memset(&scm, 0, sizeof(scm)); 1987 scm.creds = *NETLINK_CREDS(skb); 1988 if (flags & MSG_TRUNC) 1989 copied = data_skb->len; 1990 1991 skb_free_datagram(sk, skb); 1992 1993 if (nlk->cb_running && 1994 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { 1995 ret = netlink_dump(sk); 1996 if (ret) { 1997 sk->sk_err = -ret; 1998 sk_error_report(sk); 1999 } 2000 } 2001 2002 scm_recv(sock, msg, &scm, flags); 2003 out: 2004 netlink_rcv_wake(sk); 2005 return err ? : copied; 2006 } 2007 2008 static void netlink_data_ready(struct sock *sk) 2009 { 2010 BUG(); 2011 } 2012 2013 /* 2014 * We export these functions to other modules. They provide a 2015 * complete set of kernel non-blocking support for message 2016 * queueing. 2017 */ 2018 2019 struct sock * 2020 __netlink_kernel_create(struct net *net, int unit, struct module *module, 2021 struct netlink_kernel_cfg *cfg) 2022 { 2023 struct socket *sock; 2024 struct sock *sk; 2025 struct netlink_sock *nlk; 2026 struct listeners *listeners = NULL; 2027 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL; 2028 unsigned int groups; 2029 2030 BUG_ON(!nl_table); 2031 2032 if (unit < 0 || unit >= MAX_LINKS) 2033 return NULL; 2034 2035 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) 2036 return NULL; 2037 2038 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0) 2039 goto out_sock_release_nosk; 2040 2041 sk = sock->sk; 2042 2043 if (!cfg || cfg->groups < 32) 2044 groups = 32; 2045 else 2046 groups = cfg->groups; 2047 2048 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2049 if (!listeners) 2050 goto out_sock_release; 2051 2052 sk->sk_data_ready = netlink_data_ready; 2053 if (cfg && cfg->input) 2054 nlk_sk(sk)->netlink_rcv = cfg->input; 2055 2056 if (netlink_insert(sk, 0)) 2057 goto out_sock_release; 2058 2059 nlk = nlk_sk(sk); 2060 nlk->flags |= NETLINK_F_KERNEL_SOCKET; 2061 2062 netlink_table_grab(); 2063 if (!nl_table[unit].registered) { 2064 nl_table[unit].groups = groups; 2065 rcu_assign_pointer(nl_table[unit].listeners, listeners); 2066 nl_table[unit].cb_mutex = cb_mutex; 2067 nl_table[unit].module = module; 2068 if (cfg) { 2069 nl_table[unit].bind = cfg->bind; 2070 nl_table[unit].unbind = cfg->unbind; 2071 nl_table[unit].flags = cfg->flags; 2072 } 2073 nl_table[unit].registered = 1; 2074 } else { 2075 kfree(listeners); 2076 nl_table[unit].registered++; 2077 } 2078 netlink_table_ungrab(); 2079 return sk; 2080 2081 out_sock_release: 2082 kfree(listeners); 2083 netlink_kernel_release(sk); 2084 return NULL; 2085 2086 out_sock_release_nosk: 2087 sock_release(sock); 2088 return NULL; 2089 } 2090 EXPORT_SYMBOL(__netlink_kernel_create); 2091 2092 void 2093 netlink_kernel_release(struct sock *sk) 2094 { 2095 if (sk == NULL || sk->sk_socket == NULL) 2096 return; 2097 2098 sock_release(sk->sk_socket); 2099 } 2100 EXPORT_SYMBOL(netlink_kernel_release); 2101 2102 int __netlink_change_ngroups(struct sock *sk, unsigned int groups) 2103 { 2104 struct listeners *new, *old; 2105 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 2106 2107 if (groups < 32) 2108 groups = 32; 2109 2110 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) { 2111 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC); 2112 if (!new) 2113 return -ENOMEM; 2114 old = nl_deref_protected(tbl->listeners); 2115 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups)); 2116 rcu_assign_pointer(tbl->listeners, new); 2117 2118 kfree_rcu(old, rcu); 2119 } 2120 tbl->groups = groups; 2121 2122 return 0; 2123 } 2124 2125 /** 2126 * netlink_change_ngroups - change number of multicast groups 2127 * 2128 * This changes the number of multicast groups that are available 2129 * on a certain netlink family. Note that it is not possible to 2130 * change the number of groups to below 32. Also note that it does 2131 * not implicitly call netlink_clear_multicast_users() when the 2132 * number of groups is reduced. 2133 * 2134 * @sk: The kernel netlink socket, as returned by netlink_kernel_create(). 2135 * @groups: The new number of groups. 2136 */ 2137 int netlink_change_ngroups(struct sock *sk, unsigned int groups) 2138 { 2139 int err; 2140 2141 netlink_table_grab(); 2142 err = __netlink_change_ngroups(sk, groups); 2143 netlink_table_ungrab(); 2144 2145 return err; 2146 } 2147 2148 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group) 2149 { 2150 struct sock *sk; 2151 struct netlink_table *tbl = &nl_table[ksk->sk_protocol]; 2152 2153 sk_for_each_bound(sk, &tbl->mc_list) 2154 netlink_update_socket_mc(nlk_sk(sk), group, 0); 2155 } 2156 2157 struct nlmsghdr * 2158 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags) 2159 { 2160 struct nlmsghdr *nlh; 2161 int size = nlmsg_msg_size(len); 2162 2163 nlh = skb_put(skb, NLMSG_ALIGN(size)); 2164 nlh->nlmsg_type = type; 2165 nlh->nlmsg_len = size; 2166 nlh->nlmsg_flags = flags; 2167 nlh->nlmsg_pid = portid; 2168 nlh->nlmsg_seq = seq; 2169 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0) 2170 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size); 2171 return nlh; 2172 } 2173 EXPORT_SYMBOL(__nlmsg_put); 2174 2175 /* 2176 * It looks a bit ugly. 2177 * It would be better to create kernel thread. 2178 */ 2179 2180 static int netlink_dump_done(struct netlink_sock *nlk, struct sk_buff *skb, 2181 struct netlink_callback *cb, 2182 struct netlink_ext_ack *extack) 2183 { 2184 struct nlmsghdr *nlh; 2185 2186 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(nlk->dump_done_errno), 2187 NLM_F_MULTI | cb->answer_flags); 2188 if (WARN_ON(!nlh)) 2189 return -ENOBUFS; 2190 2191 nl_dump_check_consistent(cb, nlh); 2192 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, sizeof(nlk->dump_done_errno)); 2193 2194 if (extack->_msg && nlk->flags & NETLINK_F_EXT_ACK) { 2195 nlh->nlmsg_flags |= NLM_F_ACK_TLVS; 2196 if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg)) 2197 nlmsg_end(skb, nlh); 2198 } 2199 2200 return 0; 2201 } 2202 2203 static int netlink_dump(struct sock *sk) 2204 { 2205 struct netlink_sock *nlk = nlk_sk(sk); 2206 struct netlink_ext_ack extack = {}; 2207 struct netlink_callback *cb; 2208 struct sk_buff *skb = NULL; 2209 size_t max_recvmsg_len; 2210 struct module *module; 2211 int err = -ENOBUFS; 2212 int alloc_min_size; 2213 int alloc_size; 2214 2215 mutex_lock(nlk->cb_mutex); 2216 if (!nlk->cb_running) { 2217 err = -EINVAL; 2218 goto errout_skb; 2219 } 2220 2221 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) 2222 goto errout_skb; 2223 2224 /* NLMSG_GOODSIZE is small to avoid high order allocations being 2225 * required, but it makes sense to _attempt_ a 16K bytes allocation 2226 * to reduce number of system calls on dump operations, if user 2227 * ever provided a big enough buffer. 2228 */ 2229 cb = &nlk->cb; 2230 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); 2231 2232 max_recvmsg_len = READ_ONCE(nlk->max_recvmsg_len); 2233 if (alloc_min_size < max_recvmsg_len) { 2234 alloc_size = max_recvmsg_len; 2235 skb = alloc_skb(alloc_size, 2236 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) | 2237 __GFP_NOWARN | __GFP_NORETRY); 2238 } 2239 if (!skb) { 2240 alloc_size = alloc_min_size; 2241 skb = alloc_skb(alloc_size, GFP_KERNEL); 2242 } 2243 if (!skb) 2244 goto errout_skb; 2245 2246 /* Trim skb to allocated size. User is expected to provide buffer as 2247 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at 2248 * netlink_recvmsg())). dump will pack as many smaller messages as 2249 * could fit within the allocated skb. skb is typically allocated 2250 * with larger space than required (could be as much as near 2x the 2251 * requested size with align to next power of 2 approach). Allowing 2252 * dump to use the excess space makes it difficult for a user to have a 2253 * reasonable static buffer based on the expected largest dump of a 2254 * single netdev. The outcome is MSG_TRUNC error. 2255 */ 2256 skb_reserve(skb, skb_tailroom(skb) - alloc_size); 2257 2258 /* Make sure malicious BPF programs can not read unitialized memory 2259 * from skb->head -> skb->data 2260 */ 2261 skb_reset_network_header(skb); 2262 skb_reset_mac_header(skb); 2263 2264 netlink_skb_set_owner_r(skb, sk); 2265 2266 if (nlk->dump_done_errno > 0) { 2267 cb->extack = &extack; 2268 nlk->dump_done_errno = cb->dump(skb, cb); 2269 cb->extack = NULL; 2270 } 2271 2272 if (nlk->dump_done_errno > 0 || 2273 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) { 2274 mutex_unlock(nlk->cb_mutex); 2275 2276 if (sk_filter(sk, skb)) 2277 kfree_skb(skb); 2278 else 2279 __netlink_sendskb(sk, skb); 2280 return 0; 2281 } 2282 2283 if (netlink_dump_done(nlk, skb, cb, &extack)) 2284 goto errout_skb; 2285 2286 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES 2287 /* frag_list skb's data is used for compat tasks 2288 * and the regular skb's data for normal (non-compat) tasks. 2289 * See netlink_recvmsg(). 2290 */ 2291 if (unlikely(skb_shinfo(skb)->frag_list)) { 2292 if (netlink_dump_done(nlk, skb_shinfo(skb)->frag_list, cb, &extack)) 2293 goto errout_skb; 2294 } 2295 #endif 2296 2297 if (sk_filter(sk, skb)) 2298 kfree_skb(skb); 2299 else 2300 __netlink_sendskb(sk, skb); 2301 2302 if (cb->done) 2303 cb->done(cb); 2304 2305 nlk->cb_running = false; 2306 module = cb->module; 2307 skb = cb->skb; 2308 mutex_unlock(nlk->cb_mutex); 2309 module_put(module); 2310 consume_skb(skb); 2311 return 0; 2312 2313 errout_skb: 2314 mutex_unlock(nlk->cb_mutex); 2315 kfree_skb(skb); 2316 return err; 2317 } 2318 2319 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 2320 const struct nlmsghdr *nlh, 2321 struct netlink_dump_control *control) 2322 { 2323 struct netlink_sock *nlk, *nlk2; 2324 struct netlink_callback *cb; 2325 struct sock *sk; 2326 int ret; 2327 2328 refcount_inc(&skb->users); 2329 2330 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid); 2331 if (sk == NULL) { 2332 ret = -ECONNREFUSED; 2333 goto error_free; 2334 } 2335 2336 nlk = nlk_sk(sk); 2337 mutex_lock(nlk->cb_mutex); 2338 /* A dump is in progress... */ 2339 if (nlk->cb_running) { 2340 ret = -EBUSY; 2341 goto error_unlock; 2342 } 2343 /* add reference of module which cb->dump belongs to */ 2344 if (!try_module_get(control->module)) { 2345 ret = -EPROTONOSUPPORT; 2346 goto error_unlock; 2347 } 2348 2349 cb = &nlk->cb; 2350 memset(cb, 0, sizeof(*cb)); 2351 cb->dump = control->dump; 2352 cb->done = control->done; 2353 cb->nlh = nlh; 2354 cb->data = control->data; 2355 cb->module = control->module; 2356 cb->min_dump_alloc = control->min_dump_alloc; 2357 cb->skb = skb; 2358 2359 nlk2 = nlk_sk(NETLINK_CB(skb).sk); 2360 cb->strict_check = !!(nlk2->flags & NETLINK_F_STRICT_CHK); 2361 2362 if (control->start) { 2363 ret = control->start(cb); 2364 if (ret) 2365 goto error_put; 2366 } 2367 2368 nlk->cb_running = true; 2369 nlk->dump_done_errno = INT_MAX; 2370 2371 mutex_unlock(nlk->cb_mutex); 2372 2373 ret = netlink_dump(sk); 2374 2375 sock_put(sk); 2376 2377 if (ret) 2378 return ret; 2379 2380 /* We successfully started a dump, by returning -EINTR we 2381 * signal not to send ACK even if it was requested. 2382 */ 2383 return -EINTR; 2384 2385 error_put: 2386 module_put(control->module); 2387 error_unlock: 2388 sock_put(sk); 2389 mutex_unlock(nlk->cb_mutex); 2390 error_free: 2391 kfree_skb(skb); 2392 return ret; 2393 } 2394 EXPORT_SYMBOL(__netlink_dump_start); 2395 2396 static size_t 2397 netlink_ack_tlv_len(struct netlink_sock *nlk, int err, 2398 const struct netlink_ext_ack *extack) 2399 { 2400 size_t tlvlen; 2401 2402 if (!extack || !(nlk->flags & NETLINK_F_EXT_ACK)) 2403 return 0; 2404 2405 tlvlen = 0; 2406 if (extack->_msg) 2407 tlvlen += nla_total_size(strlen(extack->_msg) + 1); 2408 if (extack->cookie_len) 2409 tlvlen += nla_total_size(extack->cookie_len); 2410 2411 /* Following attributes are only reported as error (not warning) */ 2412 if (!err) 2413 return tlvlen; 2414 2415 if (extack->bad_attr) 2416 tlvlen += nla_total_size(sizeof(u32)); 2417 if (extack->policy) 2418 tlvlen += netlink_policy_dump_attr_size_estimate(extack->policy); 2419 if (extack->miss_type) 2420 tlvlen += nla_total_size(sizeof(u32)); 2421 if (extack->miss_nest) 2422 tlvlen += nla_total_size(sizeof(u32)); 2423 2424 return tlvlen; 2425 } 2426 2427 static void 2428 netlink_ack_tlv_fill(struct sk_buff *in_skb, struct sk_buff *skb, 2429 struct nlmsghdr *nlh, int err, 2430 const struct netlink_ext_ack *extack) 2431 { 2432 if (extack->_msg) 2433 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg)); 2434 if (extack->cookie_len) 2435 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE, 2436 extack->cookie_len, extack->cookie)); 2437 2438 if (!err) 2439 return; 2440 2441 if (extack->bad_attr && 2442 !WARN_ON((u8 *)extack->bad_attr < in_skb->data || 2443 (u8 *)extack->bad_attr >= in_skb->data + in_skb->len)) 2444 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS, 2445 (u8 *)extack->bad_attr - (u8 *)nlh)); 2446 if (extack->policy) 2447 netlink_policy_dump_write_attr(skb, extack->policy, 2448 NLMSGERR_ATTR_POLICY); 2449 if (extack->miss_type) 2450 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_TYPE, 2451 extack->miss_type)); 2452 if (extack->miss_nest && 2453 !WARN_ON((u8 *)extack->miss_nest < in_skb->data || 2454 (u8 *)extack->miss_nest > in_skb->data + in_skb->len)) 2455 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_NEST, 2456 (u8 *)extack->miss_nest - (u8 *)nlh)); 2457 } 2458 2459 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, 2460 const struct netlink_ext_ack *extack) 2461 { 2462 struct sk_buff *skb; 2463 struct nlmsghdr *rep; 2464 struct nlmsgerr *errmsg; 2465 size_t payload = sizeof(*errmsg); 2466 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk); 2467 unsigned int flags = 0; 2468 size_t tlvlen; 2469 2470 /* Error messages get the original request appened, unless the user 2471 * requests to cap the error message, and get extra error data if 2472 * requested. 2473 */ 2474 if (err && !(nlk->flags & NETLINK_F_CAP_ACK)) 2475 payload += nlmsg_len(nlh); 2476 else 2477 flags |= NLM_F_CAPPED; 2478 2479 tlvlen = netlink_ack_tlv_len(nlk, err, extack); 2480 if (tlvlen) 2481 flags |= NLM_F_ACK_TLVS; 2482 2483 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL); 2484 if (!skb) 2485 goto err_skb; 2486 2487 rep = nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, 2488 NLMSG_ERROR, sizeof(*errmsg), flags); 2489 if (!rep) 2490 goto err_bad_put; 2491 errmsg = nlmsg_data(rep); 2492 errmsg->error = err; 2493 errmsg->msg = *nlh; 2494 2495 if (!(flags & NLM_F_CAPPED)) { 2496 if (!nlmsg_append(skb, nlmsg_len(nlh))) 2497 goto err_bad_put; 2498 2499 memcpy(nlmsg_data(&errmsg->msg), nlmsg_data(nlh), 2500 nlmsg_len(nlh)); 2501 } 2502 2503 if (tlvlen) 2504 netlink_ack_tlv_fill(in_skb, skb, nlh, err, extack); 2505 2506 nlmsg_end(skb, rep); 2507 2508 nlmsg_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid); 2509 2510 return; 2511 2512 err_bad_put: 2513 nlmsg_free(skb); 2514 err_skb: 2515 NETLINK_CB(in_skb).sk->sk_err = ENOBUFS; 2516 sk_error_report(NETLINK_CB(in_skb).sk); 2517 } 2518 EXPORT_SYMBOL(netlink_ack); 2519 2520 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, 2521 struct nlmsghdr *, 2522 struct netlink_ext_ack *)) 2523 { 2524 struct netlink_ext_ack extack; 2525 struct nlmsghdr *nlh; 2526 int err; 2527 2528 while (skb->len >= nlmsg_total_size(0)) { 2529 int msglen; 2530 2531 memset(&extack, 0, sizeof(extack)); 2532 nlh = nlmsg_hdr(skb); 2533 err = 0; 2534 2535 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) 2536 return 0; 2537 2538 /* Only requests are handled by the kernel */ 2539 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) 2540 goto ack; 2541 2542 /* Skip control messages */ 2543 if (nlh->nlmsg_type < NLMSG_MIN_TYPE) 2544 goto ack; 2545 2546 err = cb(skb, nlh, &extack); 2547 if (err == -EINTR) 2548 goto skip; 2549 2550 ack: 2551 if (nlh->nlmsg_flags & NLM_F_ACK || err) 2552 netlink_ack(skb, nlh, err, &extack); 2553 2554 skip: 2555 msglen = NLMSG_ALIGN(nlh->nlmsg_len); 2556 if (msglen > skb->len) 2557 msglen = skb->len; 2558 skb_pull(skb, msglen); 2559 } 2560 2561 return 0; 2562 } 2563 EXPORT_SYMBOL(netlink_rcv_skb); 2564 2565 /** 2566 * nlmsg_notify - send a notification netlink message 2567 * @sk: netlink socket to use 2568 * @skb: notification message 2569 * @portid: destination netlink portid for reports or 0 2570 * @group: destination multicast group or 0 2571 * @report: 1 to report back, 0 to disable 2572 * @flags: allocation flags 2573 */ 2574 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid, 2575 unsigned int group, int report, gfp_t flags) 2576 { 2577 int err = 0; 2578 2579 if (group) { 2580 int exclude_portid = 0; 2581 2582 if (report) { 2583 refcount_inc(&skb->users); 2584 exclude_portid = portid; 2585 } 2586 2587 /* errors reported via destination sk->sk_err, but propagate 2588 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */ 2589 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags); 2590 if (err == -ESRCH) 2591 err = 0; 2592 } 2593 2594 if (report) { 2595 int err2; 2596 2597 err2 = nlmsg_unicast(sk, skb, portid); 2598 if (!err) 2599 err = err2; 2600 } 2601 2602 return err; 2603 } 2604 EXPORT_SYMBOL(nlmsg_notify); 2605 2606 #ifdef CONFIG_PROC_FS 2607 struct nl_seq_iter { 2608 struct seq_net_private p; 2609 struct rhashtable_iter hti; 2610 int link; 2611 }; 2612 2613 static void netlink_walk_start(struct nl_seq_iter *iter) 2614 { 2615 rhashtable_walk_enter(&nl_table[iter->link].hash, &iter->hti); 2616 rhashtable_walk_start(&iter->hti); 2617 } 2618 2619 static void netlink_walk_stop(struct nl_seq_iter *iter) 2620 { 2621 rhashtable_walk_stop(&iter->hti); 2622 rhashtable_walk_exit(&iter->hti); 2623 } 2624 2625 static void *__netlink_seq_next(struct seq_file *seq) 2626 { 2627 struct nl_seq_iter *iter = seq->private; 2628 struct netlink_sock *nlk; 2629 2630 do { 2631 for (;;) { 2632 nlk = rhashtable_walk_next(&iter->hti); 2633 2634 if (IS_ERR(nlk)) { 2635 if (PTR_ERR(nlk) == -EAGAIN) 2636 continue; 2637 2638 return nlk; 2639 } 2640 2641 if (nlk) 2642 break; 2643 2644 netlink_walk_stop(iter); 2645 if (++iter->link >= MAX_LINKS) 2646 return NULL; 2647 2648 netlink_walk_start(iter); 2649 } 2650 } while (sock_net(&nlk->sk) != seq_file_net(seq)); 2651 2652 return nlk; 2653 } 2654 2655 static void *netlink_seq_start(struct seq_file *seq, loff_t *posp) 2656 __acquires(RCU) 2657 { 2658 struct nl_seq_iter *iter = seq->private; 2659 void *obj = SEQ_START_TOKEN; 2660 loff_t pos; 2661 2662 iter->link = 0; 2663 2664 netlink_walk_start(iter); 2665 2666 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--) 2667 obj = __netlink_seq_next(seq); 2668 2669 return obj; 2670 } 2671 2672 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2673 { 2674 ++*pos; 2675 return __netlink_seq_next(seq); 2676 } 2677 2678 static void netlink_native_seq_stop(struct seq_file *seq, void *v) 2679 { 2680 struct nl_seq_iter *iter = seq->private; 2681 2682 if (iter->link >= MAX_LINKS) 2683 return; 2684 2685 netlink_walk_stop(iter); 2686 } 2687 2688 2689 static int netlink_native_seq_show(struct seq_file *seq, void *v) 2690 { 2691 if (v == SEQ_START_TOKEN) { 2692 seq_puts(seq, 2693 "sk Eth Pid Groups " 2694 "Rmem Wmem Dump Locks Drops Inode\n"); 2695 } else { 2696 struct sock *s = v; 2697 struct netlink_sock *nlk = nlk_sk(s); 2698 2699 seq_printf(seq, "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8u %-8lu\n", 2700 s, 2701 s->sk_protocol, 2702 nlk->portid, 2703 nlk->groups ? (u32)nlk->groups[0] : 0, 2704 sk_rmem_alloc_get(s), 2705 sk_wmem_alloc_get(s), 2706 nlk->cb_running, 2707 refcount_read(&s->sk_refcnt), 2708 atomic_read(&s->sk_drops), 2709 sock_i_ino(s) 2710 ); 2711 2712 } 2713 return 0; 2714 } 2715 2716 #ifdef CONFIG_BPF_SYSCALL 2717 struct bpf_iter__netlink { 2718 __bpf_md_ptr(struct bpf_iter_meta *, meta); 2719 __bpf_md_ptr(struct netlink_sock *, sk); 2720 }; 2721 2722 DEFINE_BPF_ITER_FUNC(netlink, struct bpf_iter_meta *meta, struct netlink_sock *sk) 2723 2724 static int netlink_prog_seq_show(struct bpf_prog *prog, 2725 struct bpf_iter_meta *meta, 2726 void *v) 2727 { 2728 struct bpf_iter__netlink ctx; 2729 2730 meta->seq_num--; /* skip SEQ_START_TOKEN */ 2731 ctx.meta = meta; 2732 ctx.sk = nlk_sk((struct sock *)v); 2733 return bpf_iter_run_prog(prog, &ctx); 2734 } 2735 2736 static int netlink_seq_show(struct seq_file *seq, void *v) 2737 { 2738 struct bpf_iter_meta meta; 2739 struct bpf_prog *prog; 2740 2741 meta.seq = seq; 2742 prog = bpf_iter_get_info(&meta, false); 2743 if (!prog) 2744 return netlink_native_seq_show(seq, v); 2745 2746 if (v != SEQ_START_TOKEN) 2747 return netlink_prog_seq_show(prog, &meta, v); 2748 2749 return 0; 2750 } 2751 2752 static void netlink_seq_stop(struct seq_file *seq, void *v) 2753 { 2754 struct bpf_iter_meta meta; 2755 struct bpf_prog *prog; 2756 2757 if (!v) { 2758 meta.seq = seq; 2759 prog = bpf_iter_get_info(&meta, true); 2760 if (prog) 2761 (void)netlink_prog_seq_show(prog, &meta, v); 2762 } 2763 2764 netlink_native_seq_stop(seq, v); 2765 } 2766 #else 2767 static int netlink_seq_show(struct seq_file *seq, void *v) 2768 { 2769 return netlink_native_seq_show(seq, v); 2770 } 2771 2772 static void netlink_seq_stop(struct seq_file *seq, void *v) 2773 { 2774 netlink_native_seq_stop(seq, v); 2775 } 2776 #endif 2777 2778 static const struct seq_operations netlink_seq_ops = { 2779 .start = netlink_seq_start, 2780 .next = netlink_seq_next, 2781 .stop = netlink_seq_stop, 2782 .show = netlink_seq_show, 2783 }; 2784 #endif 2785 2786 int netlink_register_notifier(struct notifier_block *nb) 2787 { 2788 return blocking_notifier_chain_register(&netlink_chain, nb); 2789 } 2790 EXPORT_SYMBOL(netlink_register_notifier); 2791 2792 int netlink_unregister_notifier(struct notifier_block *nb) 2793 { 2794 return blocking_notifier_chain_unregister(&netlink_chain, nb); 2795 } 2796 EXPORT_SYMBOL(netlink_unregister_notifier); 2797 2798 static const struct proto_ops netlink_ops = { 2799 .family = PF_NETLINK, 2800 .owner = THIS_MODULE, 2801 .release = netlink_release, 2802 .bind = netlink_bind, 2803 .connect = netlink_connect, 2804 .socketpair = sock_no_socketpair, 2805 .accept = sock_no_accept, 2806 .getname = netlink_getname, 2807 .poll = datagram_poll, 2808 .ioctl = netlink_ioctl, 2809 .listen = sock_no_listen, 2810 .shutdown = sock_no_shutdown, 2811 .setsockopt = netlink_setsockopt, 2812 .getsockopt = netlink_getsockopt, 2813 .sendmsg = netlink_sendmsg, 2814 .recvmsg = netlink_recvmsg, 2815 .mmap = sock_no_mmap, 2816 .sendpage = sock_no_sendpage, 2817 }; 2818 2819 static const struct net_proto_family netlink_family_ops = { 2820 .family = PF_NETLINK, 2821 .create = netlink_create, 2822 .owner = THIS_MODULE, /* for consistency 8) */ 2823 }; 2824 2825 static int __net_init netlink_net_init(struct net *net) 2826 { 2827 #ifdef CONFIG_PROC_FS 2828 if (!proc_create_net("netlink", 0, net->proc_net, &netlink_seq_ops, 2829 sizeof(struct nl_seq_iter))) 2830 return -ENOMEM; 2831 #endif 2832 return 0; 2833 } 2834 2835 static void __net_exit netlink_net_exit(struct net *net) 2836 { 2837 #ifdef CONFIG_PROC_FS 2838 remove_proc_entry("netlink", net->proc_net); 2839 #endif 2840 } 2841 2842 static void __init netlink_add_usersock_entry(void) 2843 { 2844 struct listeners *listeners; 2845 int groups = 32; 2846 2847 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2848 if (!listeners) 2849 panic("netlink_add_usersock_entry: Cannot allocate listeners\n"); 2850 2851 netlink_table_grab(); 2852 2853 nl_table[NETLINK_USERSOCK].groups = groups; 2854 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners); 2855 nl_table[NETLINK_USERSOCK].module = THIS_MODULE; 2856 nl_table[NETLINK_USERSOCK].registered = 1; 2857 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND; 2858 2859 netlink_table_ungrab(); 2860 } 2861 2862 static struct pernet_operations __net_initdata netlink_net_ops = { 2863 .init = netlink_net_init, 2864 .exit = netlink_net_exit, 2865 }; 2866 2867 static inline u32 netlink_hash(const void *data, u32 len, u32 seed) 2868 { 2869 const struct netlink_sock *nlk = data; 2870 struct netlink_compare_arg arg; 2871 2872 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid); 2873 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed); 2874 } 2875 2876 static const struct rhashtable_params netlink_rhashtable_params = { 2877 .head_offset = offsetof(struct netlink_sock, node), 2878 .key_len = netlink_compare_arg_len, 2879 .obj_hashfn = netlink_hash, 2880 .obj_cmpfn = netlink_compare, 2881 .automatic_shrinking = true, 2882 }; 2883 2884 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 2885 BTF_ID_LIST(btf_netlink_sock_id) 2886 BTF_ID(struct, netlink_sock) 2887 2888 static const struct bpf_iter_seq_info netlink_seq_info = { 2889 .seq_ops = &netlink_seq_ops, 2890 .init_seq_private = bpf_iter_init_seq_net, 2891 .fini_seq_private = bpf_iter_fini_seq_net, 2892 .seq_priv_size = sizeof(struct nl_seq_iter), 2893 }; 2894 2895 static struct bpf_iter_reg netlink_reg_info = { 2896 .target = "netlink", 2897 .ctx_arg_info_size = 1, 2898 .ctx_arg_info = { 2899 { offsetof(struct bpf_iter__netlink, sk), 2900 PTR_TO_BTF_ID_OR_NULL }, 2901 }, 2902 .seq_info = &netlink_seq_info, 2903 }; 2904 2905 static int __init bpf_iter_register(void) 2906 { 2907 netlink_reg_info.ctx_arg_info[0].btf_id = *btf_netlink_sock_id; 2908 return bpf_iter_reg_target(&netlink_reg_info); 2909 } 2910 #endif 2911 2912 static int __init netlink_proto_init(void) 2913 { 2914 int i; 2915 int err = proto_register(&netlink_proto, 0); 2916 2917 if (err != 0) 2918 goto out; 2919 2920 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 2921 err = bpf_iter_register(); 2922 if (err) 2923 goto out; 2924 #endif 2925 2926 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof_field(struct sk_buff, cb)); 2927 2928 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); 2929 if (!nl_table) 2930 goto panic; 2931 2932 for (i = 0; i < MAX_LINKS; i++) { 2933 if (rhashtable_init(&nl_table[i].hash, 2934 &netlink_rhashtable_params) < 0) { 2935 while (--i > 0) 2936 rhashtable_destroy(&nl_table[i].hash); 2937 kfree(nl_table); 2938 goto panic; 2939 } 2940 } 2941 2942 netlink_add_usersock_entry(); 2943 2944 sock_register(&netlink_family_ops); 2945 register_pernet_subsys(&netlink_net_ops); 2946 register_pernet_subsys(&netlink_tap_net_ops); 2947 /* The netlink device handler may be needed early. */ 2948 rtnetlink_init(); 2949 out: 2950 return err; 2951 panic: 2952 panic("netlink_init: Cannot allocate nl_table\n"); 2953 } 2954 2955 core_initcall(netlink_proto_init); 2956