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 77struct listeners { 78 struct rcu_head rcu; 79 unsigned long masks[]; 80}; 81 82/* state bits */ 83#define NETLINK_S_CONGESTED 0x0 84 85static inline int netlink_is_kernel(struct sock *sk) 86{ 87 return nlk_test_bit(KERNEL_SOCKET, sk); 88} 89 90struct netlink_table *nl_table __read_mostly; 91EXPORT_SYMBOL_GPL(nl_table); 92 93static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); 94 95static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS]; 96 97static 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 133static int netlink_dump(struct sock *sk, bool lock_taken); 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 */ 143DEFINE_RWLOCK(nl_table_lock); 144EXPORT_SYMBOL_GPL(nl_table_lock); 145static 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 149static BLOCKING_NOTIFIER_HEAD(netlink_chain); 150 151 152static const struct rhashtable_params netlink_rhashtable_params; 153 154void do_trace_netlink_extack(const char *msg) 155{ 156 trace_netlink_extack(msg); 157} 158EXPORT_SYMBOL(do_trace_netlink_extack); 159 160static inline u32 netlink_group_mask(u32 group) 161{ 162 if (group > 32) 163 return 0; 164 return group ? 1 << (group - 1) : 0; 165} 166 167static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb, 168 gfp_t gfp_mask) 169{ 170 unsigned int len = skb->len; 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 185static unsigned int netlink_tap_net_id; 186 187struct netlink_tap_net { 188 struct list_head netlink_tap_all; 189 struct mutex netlink_tap_lock; 190}; 191 192int 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} 208EXPORT_SYMBOL_GPL(netlink_add_tap); 209 210static 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); 228out: 229 mutex_unlock(&nn->netlink_tap_lock); 230 231 if (found) 232 module_put(nt->module); 233 234 return found ? 0 : -ENODEV; 235} 236 237int 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} 246EXPORT_SYMBOL_GPL(netlink_remove_tap); 247 248static __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 257static 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 263static 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 285static 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 316static 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 331static 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 343static 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 350static void netlink_overrun(struct sock *sk) 351{ 352 if (!nlk_test_bit(RECV_NO_ENOBUFS, sk)) { 353 if (!test_and_set_bit(NETLINK_S_CONGESTED, 354 &nlk_sk(sk)->state)) { 355 WRITE_ONCE(sk->sk_err, ENOBUFS); 356 sk_error_report(sk); 357 } 358 } 359 atomic_inc(&sk->sk_drops); 360} 361 362static void netlink_rcv_wake(struct sock *sk) 363{ 364 struct netlink_sock *nlk = nlk_sk(sk); 365 366 if (skb_queue_empty_lockless(&sk->sk_receive_queue)) 367 clear_bit(NETLINK_S_CONGESTED, &nlk->state); 368 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state)) 369 wake_up_interruptible(&nlk->wait); 370} 371 372static void netlink_skb_destructor(struct sk_buff *skb) 373{ 374 if (is_vmalloc_addr(skb->head)) { 375 if (!skb->cloned || 376 !atomic_dec_return(&(skb_shinfo(skb)->dataref))) 377 vfree_atomic(skb->head); 378 379 skb->head = NULL; 380 } 381 if (skb->sk != NULL) 382 sock_rfree(skb); 383} 384 385static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk) 386{ 387 WARN_ON(skb->sk != NULL); 388 skb->sk = sk; 389 skb->destructor = netlink_skb_destructor; 390 atomic_add(skb->truesize, &sk->sk_rmem_alloc); 391 sk_mem_charge(sk, skb->truesize); 392} 393 394static void netlink_sock_destruct(struct sock *sk) 395{ 396 struct netlink_sock *nlk = nlk_sk(sk); 397 398 if (nlk->cb_running) { 399 if (nlk->cb.done) 400 nlk->cb.done(&nlk->cb); 401 module_put(nlk->cb.module); 402 kfree_skb(nlk->cb.skb); 403 } 404 405 skb_queue_purge(&sk->sk_receive_queue); 406 407 if (!sock_flag(sk, SOCK_DEAD)) { 408 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk); 409 return; 410 } 411 412 WARN_ON(atomic_read(&sk->sk_rmem_alloc)); 413 WARN_ON(refcount_read(&sk->sk_wmem_alloc)); 414 WARN_ON(nlk_sk(sk)->groups); 415} 416 417static void netlink_sock_destruct_work(struct work_struct *work) 418{ 419 struct netlink_sock *nlk = container_of(work, struct netlink_sock, 420 work); 421 422 sk_free(&nlk->sk); 423} 424 425/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on 426 * SMP. Look, when several writers sleep and reader wakes them up, all but one 427 * immediately hit write lock and grab all the cpus. Exclusive sleep solves 428 * this, _but_ remember, it adds useless work on UP machines. 429 */ 430 431void netlink_table_grab(void) 432 __acquires(nl_table_lock) 433{ 434 might_sleep(); 435 436 write_lock_irq(&nl_table_lock); 437 438 if (atomic_read(&nl_table_users)) { 439 DECLARE_WAITQUEUE(wait, current); 440 441 add_wait_queue_exclusive(&nl_table_wait, &wait); 442 for (;;) { 443 set_current_state(TASK_UNINTERRUPTIBLE); 444 if (atomic_read(&nl_table_users) == 0) 445 break; 446 write_unlock_irq(&nl_table_lock); 447 schedule(); 448 write_lock_irq(&nl_table_lock); 449 } 450 451 __set_current_state(TASK_RUNNING); 452 remove_wait_queue(&nl_table_wait, &wait); 453 } 454} 455 456void netlink_table_ungrab(void) 457 __releases(nl_table_lock) 458{ 459 write_unlock_irq(&nl_table_lock); 460 wake_up(&nl_table_wait); 461} 462 463static inline void 464netlink_lock_table(void) 465{ 466 unsigned long flags; 467 468 /* read_lock() synchronizes us to netlink_table_grab */ 469 470 read_lock_irqsave(&nl_table_lock, flags); 471 atomic_inc(&nl_table_users); 472 read_unlock_irqrestore(&nl_table_lock, flags); 473} 474 475static inline void 476netlink_unlock_table(void) 477{ 478 if (atomic_dec_and_test(&nl_table_users)) 479 wake_up(&nl_table_wait); 480} 481 482struct netlink_compare_arg 483{ 484 possible_net_t pnet; 485 u32 portid; 486}; 487 488/* Doing sizeof directly may yield 4 extra bytes on 64-bit. */ 489#define netlink_compare_arg_len \ 490 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32)) 491 492static inline int netlink_compare(struct rhashtable_compare_arg *arg, 493 const void *ptr) 494{ 495 const struct netlink_compare_arg *x = arg->key; 496 const struct netlink_sock *nlk = ptr; 497 498 return nlk->portid != x->portid || 499 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet)); 500} 501 502static void netlink_compare_arg_init(struct netlink_compare_arg *arg, 503 struct net *net, u32 portid) 504{ 505 memset(arg, 0, sizeof(*arg)); 506 write_pnet(&arg->pnet, net); 507 arg->portid = portid; 508} 509 510static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid, 511 struct net *net) 512{ 513 struct netlink_compare_arg arg; 514 515 netlink_compare_arg_init(&arg, net, portid); 516 return rhashtable_lookup_fast(&table->hash, &arg, 517 netlink_rhashtable_params); 518} 519 520static int __netlink_insert(struct netlink_table *table, struct sock *sk) 521{ 522 struct netlink_compare_arg arg; 523 524 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid); 525 return rhashtable_lookup_insert_key(&table->hash, &arg, 526 &nlk_sk(sk)->node, 527 netlink_rhashtable_params); 528} 529 530static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid) 531{ 532 struct netlink_table *table = &nl_table[protocol]; 533 struct sock *sk; 534 535 rcu_read_lock(); 536 sk = __netlink_lookup(table, portid, net); 537 if (sk) 538 sock_hold(sk); 539 rcu_read_unlock(); 540 541 return sk; 542} 543 544static const struct proto_ops netlink_ops; 545 546static void 547netlink_update_listeners(struct sock *sk) 548{ 549 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 550 unsigned long mask; 551 unsigned int i; 552 struct listeners *listeners; 553 554 listeners = nl_deref_protected(tbl->listeners); 555 if (!listeners) 556 return; 557 558 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) { 559 mask = 0; 560 sk_for_each_bound(sk, &tbl->mc_list) { 561 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups)) 562 mask |= nlk_sk(sk)->groups[i]; 563 } 564 listeners->masks[i] = mask; 565 } 566 /* this function is only called with the netlink table "grabbed", which 567 * makes sure updates are visible before bind or setsockopt return. */ 568} 569 570static int netlink_insert(struct sock *sk, u32 portid) 571{ 572 struct netlink_table *table = &nl_table[sk->sk_protocol]; 573 int err; 574 575 lock_sock(sk); 576 577 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY; 578 if (nlk_sk(sk)->bound) 579 goto err; 580 581 /* portid can be read locklessly from netlink_getname(). */ 582 WRITE_ONCE(nlk_sk(sk)->portid, portid); 583 584 sock_hold(sk); 585 586 err = __netlink_insert(table, sk); 587 if (err) { 588 /* In case the hashtable backend returns with -EBUSY 589 * from here, it must not escape to the caller. 590 */ 591 if (unlikely(err == -EBUSY)) 592 err = -EOVERFLOW; 593 if (err == -EEXIST) 594 err = -EADDRINUSE; 595 sock_put(sk); 596 goto err; 597 } 598 599 /* We need to ensure that the socket is hashed and visible. */ 600 smp_wmb(); 601 /* Paired with lockless reads from netlink_bind(), 602 * netlink_connect() and netlink_sendmsg(). 603 */ 604 WRITE_ONCE(nlk_sk(sk)->bound, portid); 605 606err: 607 release_sock(sk); 608 return err; 609} 610 611static void netlink_remove(struct sock *sk) 612{ 613 struct netlink_table *table; 614 615 table = &nl_table[sk->sk_protocol]; 616 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node, 617 netlink_rhashtable_params)) { 618 WARN_ON(refcount_read(&sk->sk_refcnt) == 1); 619 __sock_put(sk); 620 } 621 622 netlink_table_grab(); 623 if (nlk_sk(sk)->subscriptions) { 624 __sk_del_bind_node(sk); 625 netlink_update_listeners(sk); 626 } 627 if (sk->sk_protocol == NETLINK_GENERIC) 628 atomic_inc(&genl_sk_destructing_cnt); 629 netlink_table_ungrab(); 630} 631 632static struct proto netlink_proto = { 633 .name = "NETLINK", 634 .owner = THIS_MODULE, 635 .obj_size = sizeof(struct netlink_sock), 636}; 637 638static int __netlink_create(struct net *net, struct socket *sock, 639 struct mutex *dump_cb_mutex, int protocol, 640 int kern) 641{ 642 struct sock *sk; 643 struct netlink_sock *nlk; 644 645 sock->ops = &netlink_ops; 646 647 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern); 648 if (!sk) 649 return -ENOMEM; 650 651 sock_init_data(sock, sk); 652 653 nlk = nlk_sk(sk); 654 mutex_init(&nlk->nl_cb_mutex); 655 lockdep_set_class_and_name(&nlk->nl_cb_mutex, 656 nlk_cb_mutex_keys + protocol, 657 nlk_cb_mutex_key_strings[protocol]); 658 nlk->dump_cb_mutex = dump_cb_mutex; 659 init_waitqueue_head(&nlk->wait); 660 661 sk->sk_destruct = netlink_sock_destruct; 662 sk->sk_protocol = protocol; 663 return 0; 664} 665 666static 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 void (*release)(struct sock *sock, unsigned long *groups); 675 int err = 0; 676 677 sock->state = SS_UNCONNECTED; 678 679 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) 680 return -ESOCKTNOSUPPORT; 681 682 if (protocol < 0 || protocol >= MAX_LINKS) 683 return -EPROTONOSUPPORT; 684 protocol = array_index_nospec(protocol, MAX_LINKS); 685 686 netlink_lock_table(); 687#ifdef CONFIG_MODULES 688 if (!nl_table[protocol].registered) { 689 netlink_unlock_table(); 690 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); 691 netlink_lock_table(); 692 } 693#endif 694 if (nl_table[protocol].registered && 695 try_module_get(nl_table[protocol].module)) 696 module = nl_table[protocol].module; 697 else 698 err = -EPROTONOSUPPORT; 699 cb_mutex = nl_table[protocol].cb_mutex; 700 bind = nl_table[protocol].bind; 701 unbind = nl_table[protocol].unbind; 702 release = nl_table[protocol].release; 703 netlink_unlock_table(); 704 705 if (err < 0) 706 goto out; 707 708 err = __netlink_create(net, sock, cb_mutex, protocol, kern); 709 if (err < 0) 710 goto out_module; 711 712 sock_prot_inuse_add(net, &netlink_proto, 1); 713 714 nlk = nlk_sk(sock->sk); 715 nlk->module = module; 716 nlk->netlink_bind = bind; 717 nlk->netlink_unbind = unbind; 718 nlk->netlink_release = release; 719out: 720 return err; 721 722out_module: 723 module_put(module); 724 goto out; 725} 726 727static void deferred_put_nlk_sk(struct rcu_head *head) 728{ 729 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu); 730 struct sock *sk = &nlk->sk; 731 732 kfree(nlk->groups); 733 nlk->groups = NULL; 734 735 if (!refcount_dec_and_test(&sk->sk_refcnt)) 736 return; 737 738 if (nlk->cb_running && nlk->cb.done) { 739 INIT_WORK(&nlk->work, netlink_sock_destruct_work); 740 schedule_work(&nlk->work); 741 return; 742 } 743 744 sk_free(sk); 745} 746 747static int netlink_release(struct socket *sock) 748{ 749 struct sock *sk = sock->sk; 750 struct netlink_sock *nlk; 751 752 if (!sk) 753 return 0; 754 755 netlink_remove(sk); 756 sock_orphan(sk); 757 nlk = nlk_sk(sk); 758 759 /* 760 * OK. Socket is unlinked, any packets that arrive now 761 * will be purged. 762 */ 763 if (nlk->netlink_release) 764 nlk->netlink_release(sk, nlk->groups); 765 766 /* must not acquire netlink_table_lock in any way again before unbind 767 * and notifying genetlink is done as otherwise it might deadlock 768 */ 769 if (nlk->netlink_unbind) { 770 int i; 771 772 for (i = 0; i < nlk->ngroups; i++) 773 if (test_bit(i, nlk->groups)) 774 nlk->netlink_unbind(sock_net(sk), i + 1); 775 } 776 if (sk->sk_protocol == NETLINK_GENERIC && 777 atomic_dec_return(&genl_sk_destructing_cnt) == 0) 778 wake_up(&genl_sk_destructing_waitq); 779 780 sock->sk = NULL; 781 wake_up_interruptible_all(&nlk->wait); 782 783 skb_queue_purge(&sk->sk_write_queue); 784 785 if (nlk->portid && nlk->bound) { 786 struct netlink_notify n = { 787 .net = sock_net(sk), 788 .protocol = sk->sk_protocol, 789 .portid = nlk->portid, 790 }; 791 blocking_notifier_call_chain(&netlink_chain, 792 NETLINK_URELEASE, &n); 793 } 794 795 module_put(nlk->module); 796 797 if (netlink_is_kernel(sk)) { 798 netlink_table_grab(); 799 BUG_ON(nl_table[sk->sk_protocol].registered == 0); 800 if (--nl_table[sk->sk_protocol].registered == 0) { 801 struct listeners *old; 802 803 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners); 804 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL); 805 kfree_rcu(old, rcu); 806 nl_table[sk->sk_protocol].module = NULL; 807 nl_table[sk->sk_protocol].bind = NULL; 808 nl_table[sk->sk_protocol].unbind = NULL; 809 nl_table[sk->sk_protocol].flags = 0; 810 nl_table[sk->sk_protocol].registered = 0; 811 } 812 netlink_table_ungrab(); 813 } 814 815 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1); 816 817 /* Because struct net might disappear soon, do not keep a pointer. */ 818 if (!sk->sk_net_refcnt && sock_net(sk) != &init_net) { 819 __netns_tracker_free(sock_net(sk), &sk->ns_tracker, false); 820 /* Because of deferred_put_nlk_sk and use of work queue, 821 * it is possible netns will be freed before this socket. 822 */ 823 sock_net_set(sk, &init_net); 824 __netns_tracker_alloc(&init_net, &sk->ns_tracker, 825 false, GFP_KERNEL); 826 } 827 call_rcu(&nlk->rcu, deferred_put_nlk_sk); 828 return 0; 829} 830 831static int netlink_autobind(struct socket *sock) 832{ 833 struct sock *sk = sock->sk; 834 struct net *net = sock_net(sk); 835 struct netlink_table *table = &nl_table[sk->sk_protocol]; 836 s32 portid = task_tgid_vnr(current); 837 int err; 838 s32 rover = -4096; 839 bool ok; 840 841retry: 842 cond_resched(); 843 rcu_read_lock(); 844 ok = !__netlink_lookup(table, portid, net); 845 rcu_read_unlock(); 846 if (!ok) { 847 /* Bind collision, search negative portid values. */ 848 if (rover == -4096) 849 /* rover will be in range [S32_MIN, -4097] */ 850 rover = S32_MIN + get_random_u32_below(-4096 - S32_MIN); 851 else if (rover >= -4096) 852 rover = -4097; 853 portid = rover--; 854 goto retry; 855 } 856 857 err = netlink_insert(sk, portid); 858 if (err == -EADDRINUSE) 859 goto retry; 860 861 /* If 2 threads race to autobind, that is fine. */ 862 if (err == -EBUSY) 863 err = 0; 864 865 return err; 866} 867 868/** 869 * __netlink_ns_capable - General netlink message capability test 870 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace. 871 * @user_ns: The user namespace of the capability to use 872 * @cap: The capability to use 873 * 874 * Test to see if the opener of the socket we received the message 875 * from had when the netlink socket was created and the sender of the 876 * message has the capability @cap in the user namespace @user_ns. 877 */ 878bool __netlink_ns_capable(const struct netlink_skb_parms *nsp, 879 struct user_namespace *user_ns, int cap) 880{ 881 return ((nsp->flags & NETLINK_SKB_DST) || 882 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) && 883 ns_capable(user_ns, cap); 884} 885EXPORT_SYMBOL(__netlink_ns_capable); 886 887/** 888 * netlink_ns_capable - General netlink message capability test 889 * @skb: socket buffer holding a netlink command from userspace 890 * @user_ns: The user namespace of the capability to use 891 * @cap: The capability to use 892 * 893 * Test to see if the opener of the socket we received the message 894 * from had when the netlink socket was created and the sender of the 895 * message has the capability @cap in the user namespace @user_ns. 896 */ 897bool netlink_ns_capable(const struct sk_buff *skb, 898 struct user_namespace *user_ns, int cap) 899{ 900 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap); 901} 902EXPORT_SYMBOL(netlink_ns_capable); 903 904/** 905 * netlink_capable - Netlink global message capability test 906 * @skb: socket buffer holding a netlink command from userspace 907 * @cap: The capability to use 908 * 909 * Test to see if the opener of the socket we received the message 910 * from had when the netlink socket was created and the sender of the 911 * message has the capability @cap in all user namespaces. 912 */ 913bool netlink_capable(const struct sk_buff *skb, int cap) 914{ 915 return netlink_ns_capable(skb, &init_user_ns, cap); 916} 917EXPORT_SYMBOL(netlink_capable); 918 919/** 920 * netlink_net_capable - Netlink network namespace message capability test 921 * @skb: socket buffer holding a netlink command from userspace 922 * @cap: The capability to use 923 * 924 * Test to see if the opener of the socket we received the message 925 * from had when the netlink socket was created and the sender of the 926 * message has the capability @cap over the network namespace of 927 * the socket we received the message from. 928 */ 929bool netlink_net_capable(const struct sk_buff *skb, int cap) 930{ 931 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap); 932} 933EXPORT_SYMBOL(netlink_net_capable); 934 935static inline int netlink_allowed(const struct socket *sock, unsigned int flag) 936{ 937 return (nl_table[sock->sk->sk_protocol].flags & flag) || 938 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN); 939} 940 941static void 942netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) 943{ 944 struct netlink_sock *nlk = nlk_sk(sk); 945 946 if (nlk->subscriptions && !subscriptions) 947 __sk_del_bind_node(sk); 948 else if (!nlk->subscriptions && subscriptions) 949 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); 950 nlk->subscriptions = subscriptions; 951} 952 953static int netlink_realloc_groups(struct sock *sk) 954{ 955 struct netlink_sock *nlk = nlk_sk(sk); 956 unsigned int groups; 957 unsigned long *new_groups; 958 int err = 0; 959 960 netlink_table_grab(); 961 962 groups = nl_table[sk->sk_protocol].groups; 963 if (!nl_table[sk->sk_protocol].registered) { 964 err = -ENOENT; 965 goto out_unlock; 966 } 967 968 if (nlk->ngroups >= groups) 969 goto out_unlock; 970 971 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC); 972 if (new_groups == NULL) { 973 err = -ENOMEM; 974 goto out_unlock; 975 } 976 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0, 977 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups)); 978 979 nlk->groups = new_groups; 980 nlk->ngroups = groups; 981 out_unlock: 982 netlink_table_ungrab(); 983 return err; 984} 985 986static void netlink_undo_bind(int group, long unsigned int groups, 987 struct sock *sk) 988{ 989 struct netlink_sock *nlk = nlk_sk(sk); 990 int undo; 991 992 if (!nlk->netlink_unbind) 993 return; 994 995 for (undo = 0; undo < group; undo++) 996 if (test_bit(undo, &groups)) 997 nlk->netlink_unbind(sock_net(sk), undo + 1); 998} 999 1000static int netlink_bind(struct socket *sock, struct sockaddr *addr, 1001 int addr_len) 1002{ 1003 struct sock *sk = sock->sk; 1004 struct net *net = sock_net(sk); 1005 struct netlink_sock *nlk = nlk_sk(sk); 1006 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 1007 int err = 0; 1008 unsigned long groups; 1009 bool bound; 1010 1011 if (addr_len < sizeof(struct sockaddr_nl)) 1012 return -EINVAL; 1013 1014 if (nladdr->nl_family != AF_NETLINK) 1015 return -EINVAL; 1016 groups = nladdr->nl_groups; 1017 1018 /* Only superuser is allowed to listen multicasts */ 1019 if (groups) { 1020 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) 1021 return -EPERM; 1022 err = netlink_realloc_groups(sk); 1023 if (err) 1024 return err; 1025 } 1026 1027 if (nlk->ngroups < BITS_PER_LONG) 1028 groups &= (1UL << nlk->ngroups) - 1; 1029 1030 /* Paired with WRITE_ONCE() in netlink_insert() */ 1031 bound = READ_ONCE(nlk->bound); 1032 if (bound) { 1033 /* Ensure nlk->portid is up-to-date. */ 1034 smp_rmb(); 1035 1036 if (nladdr->nl_pid != nlk->portid) 1037 return -EINVAL; 1038 } 1039 1040 if (nlk->netlink_bind && groups) { 1041 int group; 1042 1043 /* nl_groups is a u32, so cap the maximum groups we can bind */ 1044 for (group = 0; group < BITS_PER_TYPE(u32); group++) { 1045 if (!test_bit(group, &groups)) 1046 continue; 1047 err = nlk->netlink_bind(net, group + 1); 1048 if (!err) 1049 continue; 1050 netlink_undo_bind(group, groups, sk); 1051 return err; 1052 } 1053 } 1054 1055 /* No need for barriers here as we return to user-space without 1056 * using any of the bound attributes. 1057 */ 1058 netlink_lock_table(); 1059 if (!bound) { 1060 err = nladdr->nl_pid ? 1061 netlink_insert(sk, nladdr->nl_pid) : 1062 netlink_autobind(sock); 1063 if (err) { 1064 netlink_undo_bind(BITS_PER_TYPE(u32), groups, sk); 1065 goto unlock; 1066 } 1067 } 1068 1069 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) 1070 goto unlock; 1071 netlink_unlock_table(); 1072 1073 netlink_table_grab(); 1074 netlink_update_subscriptions(sk, nlk->subscriptions + 1075 hweight32(groups) - 1076 hweight32(nlk->groups[0])); 1077 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups; 1078 netlink_update_listeners(sk); 1079 netlink_table_ungrab(); 1080 1081 return 0; 1082 1083unlock: 1084 netlink_unlock_table(); 1085 return err; 1086} 1087 1088static int netlink_connect(struct socket *sock, struct sockaddr *addr, 1089 int alen, int flags) 1090{ 1091 int err = 0; 1092 struct sock *sk = sock->sk; 1093 struct netlink_sock *nlk = nlk_sk(sk); 1094 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; 1095 1096 if (alen < sizeof(addr->sa_family)) 1097 return -EINVAL; 1098 1099 if (addr->sa_family == AF_UNSPEC) { 1100 /* paired with READ_ONCE() in netlink_getsockbyportid() */ 1101 WRITE_ONCE(sk->sk_state, NETLINK_UNCONNECTED); 1102 /* dst_portid and dst_group can be read locklessly */ 1103 WRITE_ONCE(nlk->dst_portid, 0); 1104 WRITE_ONCE(nlk->dst_group, 0); 1105 return 0; 1106 } 1107 if (addr->sa_family != AF_NETLINK) 1108 return -EINVAL; 1109 1110 if (alen < sizeof(struct sockaddr_nl)) 1111 return -EINVAL; 1112 1113 if ((nladdr->nl_groups || nladdr->nl_pid) && 1114 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) 1115 return -EPERM; 1116 1117 /* No need for barriers here as we return to user-space without 1118 * using any of the bound attributes. 1119 * Paired with WRITE_ONCE() in netlink_insert(). 1120 */ 1121 if (!READ_ONCE(nlk->bound)) 1122 err = netlink_autobind(sock); 1123 1124 if (err == 0) { 1125 /* paired with READ_ONCE() in netlink_getsockbyportid() */ 1126 WRITE_ONCE(sk->sk_state, NETLINK_CONNECTED); 1127 /* dst_portid and dst_group can be read locklessly */ 1128 WRITE_ONCE(nlk->dst_portid, nladdr->nl_pid); 1129 WRITE_ONCE(nlk->dst_group, ffs(nladdr->nl_groups)); 1130 } 1131 1132 return err; 1133} 1134 1135static int netlink_getname(struct socket *sock, struct sockaddr *addr, 1136 int peer) 1137{ 1138 struct sock *sk = sock->sk; 1139 struct netlink_sock *nlk = nlk_sk(sk); 1140 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr); 1141 1142 nladdr->nl_family = AF_NETLINK; 1143 nladdr->nl_pad = 0; 1144 1145 if (peer) { 1146 /* Paired with WRITE_ONCE() in netlink_connect() */ 1147 nladdr->nl_pid = READ_ONCE(nlk->dst_portid); 1148 nladdr->nl_groups = netlink_group_mask(READ_ONCE(nlk->dst_group)); 1149 } else { 1150 /* Paired with WRITE_ONCE() in netlink_insert() */ 1151 nladdr->nl_pid = READ_ONCE(nlk->portid); 1152 netlink_lock_table(); 1153 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; 1154 netlink_unlock_table(); 1155 } 1156 return sizeof(*nladdr); 1157} 1158 1159static int netlink_ioctl(struct socket *sock, unsigned int cmd, 1160 unsigned long arg) 1161{ 1162 /* try to hand this ioctl down to the NIC drivers. 1163 */ 1164 return -ENOIOCTLCMD; 1165} 1166 1167static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid) 1168{ 1169 struct sock *sock; 1170 struct netlink_sock *nlk; 1171 1172 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid); 1173 if (!sock) 1174 return ERR_PTR(-ECONNREFUSED); 1175 1176 /* Don't bother queuing skb if kernel socket has no input function */ 1177 nlk = nlk_sk(sock); 1178 /* dst_portid and sk_state can be changed in netlink_connect() */ 1179 if (READ_ONCE(sock->sk_state) == NETLINK_CONNECTED && 1180 READ_ONCE(nlk->dst_portid) != nlk_sk(ssk)->portid) { 1181 sock_put(sock); 1182 return ERR_PTR(-ECONNREFUSED); 1183 } 1184 return sock; 1185} 1186 1187struct sock *netlink_getsockbyfilp(struct file *filp) 1188{ 1189 struct inode *inode = file_inode(filp); 1190 struct sock *sock; 1191 1192 if (!S_ISSOCK(inode->i_mode)) 1193 return ERR_PTR(-ENOTSOCK); 1194 1195 sock = SOCKET_I(inode)->sk; 1196 if (sock->sk_family != AF_NETLINK) 1197 return ERR_PTR(-EINVAL); 1198 1199 sock_hold(sock); 1200 return sock; 1201} 1202 1203struct sk_buff *netlink_alloc_large_skb(unsigned int size, int broadcast) 1204{ 1205 size_t head_size = SKB_HEAD_ALIGN(size); 1206 struct sk_buff *skb; 1207 void *data; 1208 1209 if (head_size <= PAGE_SIZE || broadcast) 1210 return alloc_skb(size, GFP_KERNEL); 1211 1212 data = kvmalloc(head_size, GFP_KERNEL); 1213 if (!data) 1214 return NULL; 1215 1216 skb = __build_skb(data, head_size); 1217 if (!skb) 1218 kvfree(data); 1219 else if (is_vmalloc_addr(data)) 1220 skb->destructor = netlink_skb_destructor; 1221 1222 return skb; 1223} 1224 1225/* 1226 * Attach a skb to a netlink socket. 1227 * The caller must hold a reference to the destination socket. On error, the 1228 * reference is dropped. The skb is not send to the destination, just all 1229 * all error checks are performed and memory in the queue is reserved. 1230 * Return values: 1231 * < 0: error. skb freed, reference to sock dropped. 1232 * 0: continue 1233 * 1: repeat lookup - reference dropped while waiting for socket memory. 1234 */ 1235int netlink_attachskb(struct sock *sk, struct sk_buff *skb, 1236 long *timeo, struct sock *ssk) 1237{ 1238 struct netlink_sock *nlk; 1239 1240 nlk = nlk_sk(sk); 1241 1242 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 1243 test_bit(NETLINK_S_CONGESTED, &nlk->state))) { 1244 DECLARE_WAITQUEUE(wait, current); 1245 if (!*timeo) { 1246 if (!ssk || netlink_is_kernel(ssk)) 1247 netlink_overrun(sk); 1248 sock_put(sk); 1249 kfree_skb(skb); 1250 return -EAGAIN; 1251 } 1252 1253 __set_current_state(TASK_INTERRUPTIBLE); 1254 add_wait_queue(&nlk->wait, &wait); 1255 1256 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || 1257 test_bit(NETLINK_S_CONGESTED, &nlk->state)) && 1258 !sock_flag(sk, SOCK_DEAD)) 1259 *timeo = schedule_timeout(*timeo); 1260 1261 __set_current_state(TASK_RUNNING); 1262 remove_wait_queue(&nlk->wait, &wait); 1263 sock_put(sk); 1264 1265 if (signal_pending(current)) { 1266 kfree_skb(skb); 1267 return sock_intr_errno(*timeo); 1268 } 1269 return 1; 1270 } 1271 netlink_skb_set_owner_r(skb, sk); 1272 return 0; 1273} 1274 1275static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb) 1276{ 1277 int len = skb->len; 1278 1279 netlink_deliver_tap(sock_net(sk), skb); 1280 1281 skb_queue_tail(&sk->sk_receive_queue, skb); 1282 sk->sk_data_ready(sk); 1283 return len; 1284} 1285 1286int netlink_sendskb(struct sock *sk, struct sk_buff *skb) 1287{ 1288 int len = __netlink_sendskb(sk, skb); 1289 1290 sock_put(sk); 1291 return len; 1292} 1293 1294void netlink_detachskb(struct sock *sk, struct sk_buff *skb) 1295{ 1296 kfree_skb(skb); 1297 sock_put(sk); 1298} 1299 1300static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation) 1301{ 1302 int delta; 1303 1304 WARN_ON(skb->sk != NULL); 1305 delta = skb->end - skb->tail; 1306 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize) 1307 return skb; 1308 1309 if (skb_shared(skb)) { 1310 struct sk_buff *nskb = skb_clone(skb, allocation); 1311 if (!nskb) 1312 return skb; 1313 consume_skb(skb); 1314 skb = nskb; 1315 } 1316 1317 pskb_expand_head(skb, 0, -delta, 1318 (allocation & ~__GFP_DIRECT_RECLAIM) | 1319 __GFP_NOWARN | __GFP_NORETRY); 1320 return skb; 1321} 1322 1323static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb, 1324 struct sock *ssk) 1325{ 1326 int ret; 1327 struct netlink_sock *nlk = nlk_sk(sk); 1328 1329 ret = -ECONNREFUSED; 1330 if (nlk->netlink_rcv != NULL) { 1331 ret = skb->len; 1332 netlink_skb_set_owner_r(skb, sk); 1333 NETLINK_CB(skb).sk = ssk; 1334 netlink_deliver_tap_kernel(sk, ssk, skb); 1335 nlk->netlink_rcv(skb); 1336 consume_skb(skb); 1337 } else { 1338 kfree_skb(skb); 1339 } 1340 sock_put(sk); 1341 return ret; 1342} 1343 1344int netlink_unicast(struct sock *ssk, struct sk_buff *skb, 1345 u32 portid, int nonblock) 1346{ 1347 struct sock *sk; 1348 int err; 1349 long timeo; 1350 1351 skb = netlink_trim(skb, gfp_any()); 1352 1353 timeo = sock_sndtimeo(ssk, nonblock); 1354retry: 1355 sk = netlink_getsockbyportid(ssk, portid); 1356 if (IS_ERR(sk)) { 1357 kfree_skb(skb); 1358 return PTR_ERR(sk); 1359 } 1360 if (netlink_is_kernel(sk)) 1361 return netlink_unicast_kernel(sk, skb, ssk); 1362 1363 if (sk_filter(sk, skb)) { 1364 err = skb->len; 1365 kfree_skb(skb); 1366 sock_put(sk); 1367 return err; 1368 } 1369 1370 err = netlink_attachskb(sk, skb, &timeo, ssk); 1371 if (err == 1) 1372 goto retry; 1373 if (err) 1374 return err; 1375 1376 return netlink_sendskb(sk, skb); 1377} 1378EXPORT_SYMBOL(netlink_unicast); 1379 1380int netlink_has_listeners(struct sock *sk, unsigned int group) 1381{ 1382 int res = 0; 1383 struct listeners *listeners; 1384 1385 BUG_ON(!netlink_is_kernel(sk)); 1386 1387 rcu_read_lock(); 1388 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners); 1389 1390 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups) 1391 res = test_bit(group - 1, listeners->masks); 1392 1393 rcu_read_unlock(); 1394 1395 return res; 1396} 1397EXPORT_SYMBOL_GPL(netlink_has_listeners); 1398 1399bool netlink_strict_get_check(struct sk_buff *skb) 1400{ 1401 return nlk_test_bit(STRICT_CHK, NETLINK_CB(skb).sk); 1402} 1403EXPORT_SYMBOL_GPL(netlink_strict_get_check); 1404 1405static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) 1406{ 1407 struct netlink_sock *nlk = nlk_sk(sk); 1408 1409 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && 1410 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) { 1411 netlink_skb_set_owner_r(skb, sk); 1412 __netlink_sendskb(sk, skb); 1413 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1); 1414 } 1415 return -1; 1416} 1417 1418struct netlink_broadcast_data { 1419 struct sock *exclude_sk; 1420 struct net *net; 1421 u32 portid; 1422 u32 group; 1423 int failure; 1424 int delivery_failure; 1425 int congested; 1426 int delivered; 1427 gfp_t allocation; 1428 struct sk_buff *skb, *skb2; 1429 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data); 1430 void *tx_data; 1431}; 1432 1433static void do_one_broadcast(struct sock *sk, 1434 struct netlink_broadcast_data *p) 1435{ 1436 struct netlink_sock *nlk = nlk_sk(sk); 1437 int val; 1438 1439 if (p->exclude_sk == sk) 1440 return; 1441 1442 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups || 1443 !test_bit(p->group - 1, nlk->groups)) 1444 return; 1445 1446 if (!net_eq(sock_net(sk), p->net)) { 1447 if (!nlk_test_bit(LISTEN_ALL_NSID, sk)) 1448 return; 1449 1450 if (!peernet_has_id(sock_net(sk), p->net)) 1451 return; 1452 1453 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns, 1454 CAP_NET_BROADCAST)) 1455 return; 1456 } 1457 1458 if (p->failure) { 1459 netlink_overrun(sk); 1460 return; 1461 } 1462 1463 sock_hold(sk); 1464 if (p->skb2 == NULL) { 1465 if (skb_shared(p->skb)) { 1466 p->skb2 = skb_clone(p->skb, p->allocation); 1467 } else { 1468 p->skb2 = skb_get(p->skb); 1469 /* 1470 * skb ownership may have been set when 1471 * delivered to a previous socket. 1472 */ 1473 skb_orphan(p->skb2); 1474 } 1475 } 1476 if (p->skb2 == NULL) { 1477 netlink_overrun(sk); 1478 /* Clone failed. Notify ALL listeners. */ 1479 p->failure = 1; 1480 if (nlk_test_bit(BROADCAST_SEND_ERROR, sk)) 1481 p->delivery_failure = 1; 1482 goto out; 1483 } 1484 1485 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) { 1486 kfree_skb(p->skb2); 1487 p->skb2 = NULL; 1488 goto out; 1489 } 1490 1491 if (sk_filter(sk, p->skb2)) { 1492 kfree_skb(p->skb2); 1493 p->skb2 = NULL; 1494 goto out; 1495 } 1496 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net); 1497 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED) 1498 NETLINK_CB(p->skb2).nsid_is_set = true; 1499 val = netlink_broadcast_deliver(sk, p->skb2); 1500 if (val < 0) { 1501 netlink_overrun(sk); 1502 if (nlk_test_bit(BROADCAST_SEND_ERROR, sk)) 1503 p->delivery_failure = 1; 1504 } else { 1505 p->congested |= val; 1506 p->delivered = 1; 1507 p->skb2 = NULL; 1508 } 1509out: 1510 sock_put(sk); 1511} 1512 1513int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, 1514 u32 portid, 1515 u32 group, gfp_t allocation, 1516 netlink_filter_fn filter, 1517 void *filter_data) 1518{ 1519 struct net *net = sock_net(ssk); 1520 struct netlink_broadcast_data info; 1521 struct sock *sk; 1522 1523 skb = netlink_trim(skb, allocation); 1524 1525 info.exclude_sk = ssk; 1526 info.net = net; 1527 info.portid = portid; 1528 info.group = group; 1529 info.failure = 0; 1530 info.delivery_failure = 0; 1531 info.congested = 0; 1532 info.delivered = 0; 1533 info.allocation = allocation; 1534 info.skb = skb; 1535 info.skb2 = NULL; 1536 info.tx_filter = filter; 1537 info.tx_data = filter_data; 1538 1539 /* While we sleep in clone, do not allow to change socket list */ 1540 1541 netlink_lock_table(); 1542 1543 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) 1544 do_one_broadcast(sk, &info); 1545 1546 consume_skb(skb); 1547 1548 netlink_unlock_table(); 1549 1550 if (info.delivery_failure) { 1551 kfree_skb(info.skb2); 1552 return -ENOBUFS; 1553 } 1554 consume_skb(info.skb2); 1555 1556 if (info.delivered) { 1557 if (info.congested && gfpflags_allow_blocking(allocation)) 1558 yield(); 1559 return 0; 1560 } 1561 return -ESRCH; 1562} 1563EXPORT_SYMBOL(netlink_broadcast_filtered); 1564 1565int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid, 1566 u32 group, gfp_t allocation) 1567{ 1568 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation, 1569 NULL, NULL); 1570} 1571EXPORT_SYMBOL(netlink_broadcast); 1572 1573struct netlink_set_err_data { 1574 struct sock *exclude_sk; 1575 u32 portid; 1576 u32 group; 1577 int code; 1578}; 1579 1580static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p) 1581{ 1582 struct netlink_sock *nlk = nlk_sk(sk); 1583 int ret = 0; 1584 1585 if (sk == p->exclude_sk) 1586 goto out; 1587 1588 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk))) 1589 goto out; 1590 1591 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups || 1592 !test_bit(p->group - 1, nlk->groups)) 1593 goto out; 1594 1595 if (p->code == ENOBUFS && nlk_test_bit(RECV_NO_ENOBUFS, sk)) { 1596 ret = 1; 1597 goto out; 1598 } 1599 1600 WRITE_ONCE(sk->sk_err, p->code); 1601 sk_error_report(sk); 1602out: 1603 return ret; 1604} 1605 1606/** 1607 * netlink_set_err - report error to broadcast listeners 1608 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create() 1609 * @portid: the PORTID of a process that we want to skip (if any) 1610 * @group: the broadcast group that will notice the error 1611 * @code: error code, must be negative (as usual in kernelspace) 1612 * 1613 * This function returns the number of broadcast listeners that have set the 1614 * NETLINK_NO_ENOBUFS socket option. 1615 */ 1616int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code) 1617{ 1618 struct netlink_set_err_data info; 1619 unsigned long flags; 1620 struct sock *sk; 1621 int ret = 0; 1622 1623 info.exclude_sk = ssk; 1624 info.portid = portid; 1625 info.group = group; 1626 /* sk->sk_err wants a positive error value */ 1627 info.code = -code; 1628 1629 read_lock_irqsave(&nl_table_lock, flags); 1630 1631 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) 1632 ret += do_one_set_err(sk, &info); 1633 1634 read_unlock_irqrestore(&nl_table_lock, flags); 1635 return ret; 1636} 1637EXPORT_SYMBOL(netlink_set_err); 1638 1639/* must be called with netlink table grabbed */ 1640static void netlink_update_socket_mc(struct netlink_sock *nlk, 1641 unsigned int group, 1642 int is_new) 1643{ 1644 int old, new = !!is_new, subscriptions; 1645 1646 old = test_bit(group - 1, nlk->groups); 1647 subscriptions = nlk->subscriptions - old + new; 1648 __assign_bit(group - 1, nlk->groups, new); 1649 netlink_update_subscriptions(&nlk->sk, subscriptions); 1650 netlink_update_listeners(&nlk->sk); 1651} 1652 1653static int netlink_setsockopt(struct socket *sock, int level, int optname, 1654 sockptr_t optval, unsigned int optlen) 1655{ 1656 struct sock *sk = sock->sk; 1657 struct netlink_sock *nlk = nlk_sk(sk); 1658 unsigned int val = 0; 1659 int nr = -1; 1660 1661 if (level != SOL_NETLINK) 1662 return -ENOPROTOOPT; 1663 1664 if (optlen >= sizeof(int) && 1665 copy_from_sockptr(&val, optval, sizeof(val))) 1666 return -EFAULT; 1667 1668 switch (optname) { 1669 case NETLINK_PKTINFO: 1670 nr = NETLINK_F_RECV_PKTINFO; 1671 break; 1672 case NETLINK_ADD_MEMBERSHIP: 1673 case NETLINK_DROP_MEMBERSHIP: { 1674 int err; 1675 1676 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) 1677 return -EPERM; 1678 err = netlink_realloc_groups(sk); 1679 if (err) 1680 return err; 1681 if (!val || val - 1 >= nlk->ngroups) 1682 return -EINVAL; 1683 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) { 1684 err = nlk->netlink_bind(sock_net(sk), val); 1685 if (err) 1686 return err; 1687 } 1688 netlink_table_grab(); 1689 netlink_update_socket_mc(nlk, val, 1690 optname == NETLINK_ADD_MEMBERSHIP); 1691 netlink_table_ungrab(); 1692 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind) 1693 nlk->netlink_unbind(sock_net(sk), val); 1694 1695 break; 1696 } 1697 case NETLINK_BROADCAST_ERROR: 1698 nr = NETLINK_F_BROADCAST_SEND_ERROR; 1699 break; 1700 case NETLINK_NO_ENOBUFS: 1701 assign_bit(NETLINK_F_RECV_NO_ENOBUFS, &nlk->flags, val); 1702 if (val) { 1703 clear_bit(NETLINK_S_CONGESTED, &nlk->state); 1704 wake_up_interruptible(&nlk->wait); 1705 } 1706 break; 1707 case NETLINK_LISTEN_ALL_NSID: 1708 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST)) 1709 return -EPERM; 1710 nr = NETLINK_F_LISTEN_ALL_NSID; 1711 break; 1712 case NETLINK_CAP_ACK: 1713 nr = NETLINK_F_CAP_ACK; 1714 break; 1715 case NETLINK_EXT_ACK: 1716 nr = NETLINK_F_EXT_ACK; 1717 break; 1718 case NETLINK_GET_STRICT_CHK: 1719 nr = NETLINK_F_STRICT_CHK; 1720 break; 1721 default: 1722 return -ENOPROTOOPT; 1723 } 1724 if (nr >= 0) 1725 assign_bit(nr, &nlk->flags, val); 1726 return 0; 1727} 1728 1729static int netlink_getsockopt(struct socket *sock, int level, int optname, 1730 char __user *optval, int __user *optlen) 1731{ 1732 struct sock *sk = sock->sk; 1733 struct netlink_sock *nlk = nlk_sk(sk); 1734 unsigned int flag; 1735 int len, val; 1736 1737 if (level != SOL_NETLINK) 1738 return -ENOPROTOOPT; 1739 1740 if (get_user(len, optlen)) 1741 return -EFAULT; 1742 if (len < 0) 1743 return -EINVAL; 1744 1745 switch (optname) { 1746 case NETLINK_PKTINFO: 1747 flag = NETLINK_F_RECV_PKTINFO; 1748 break; 1749 case NETLINK_BROADCAST_ERROR: 1750 flag = NETLINK_F_BROADCAST_SEND_ERROR; 1751 break; 1752 case NETLINK_NO_ENOBUFS: 1753 flag = NETLINK_F_RECV_NO_ENOBUFS; 1754 break; 1755 case NETLINK_LIST_MEMBERSHIPS: { 1756 int pos, idx, shift, err = 0; 1757 1758 netlink_lock_table(); 1759 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) { 1760 if (len - pos < sizeof(u32)) 1761 break; 1762 1763 idx = pos / sizeof(unsigned long); 1764 shift = (pos % sizeof(unsigned long)) * 8; 1765 if (put_user((u32)(nlk->groups[idx] >> shift), 1766 (u32 __user *)(optval + pos))) { 1767 err = -EFAULT; 1768 break; 1769 } 1770 } 1771 if (put_user(ALIGN(BITS_TO_BYTES(nlk->ngroups), sizeof(u32)), optlen)) 1772 err = -EFAULT; 1773 netlink_unlock_table(); 1774 return err; 1775 } 1776 case NETLINK_LISTEN_ALL_NSID: 1777 flag = NETLINK_F_LISTEN_ALL_NSID; 1778 break; 1779 case NETLINK_CAP_ACK: 1780 flag = NETLINK_F_CAP_ACK; 1781 break; 1782 case NETLINK_EXT_ACK: 1783 flag = NETLINK_F_EXT_ACK; 1784 break; 1785 case NETLINK_GET_STRICT_CHK: 1786 flag = NETLINK_F_STRICT_CHK; 1787 break; 1788 default: 1789 return -ENOPROTOOPT; 1790 } 1791 1792 if (len < sizeof(int)) 1793 return -EINVAL; 1794 1795 len = sizeof(int); 1796 val = test_bit(flag, &nlk->flags); 1797 1798 if (put_user(len, optlen) || 1799 copy_to_user(optval, &val, len)) 1800 return -EFAULT; 1801 1802 return 0; 1803} 1804 1805static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) 1806{ 1807 struct nl_pktinfo info; 1808 1809 info.group = NETLINK_CB(skb).dst_group; 1810 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); 1811} 1812 1813static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg, 1814 struct sk_buff *skb) 1815{ 1816 if (!NETLINK_CB(skb).nsid_is_set) 1817 return; 1818 1819 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int), 1820 &NETLINK_CB(skb).nsid); 1821} 1822 1823static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 1824{ 1825 struct sock *sk = sock->sk; 1826 struct netlink_sock *nlk = nlk_sk(sk); 1827 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); 1828 u32 dst_portid; 1829 u32 dst_group; 1830 struct sk_buff *skb; 1831 int err; 1832 struct scm_cookie scm; 1833 u32 netlink_skb_flags = 0; 1834 1835 if (msg->msg_flags & MSG_OOB) 1836 return -EOPNOTSUPP; 1837 1838 if (len == 0) { 1839 pr_warn_once("Zero length message leads to an empty skb\n"); 1840 return -ENODATA; 1841 } 1842 1843 err = scm_send(sock, msg, &scm, true); 1844 if (err < 0) 1845 return err; 1846 1847 if (msg->msg_namelen) { 1848 err = -EINVAL; 1849 if (msg->msg_namelen < sizeof(struct sockaddr_nl)) 1850 goto out; 1851 if (addr->nl_family != AF_NETLINK) 1852 goto out; 1853 dst_portid = addr->nl_pid; 1854 dst_group = ffs(addr->nl_groups); 1855 err = -EPERM; 1856 if ((dst_group || dst_portid) && 1857 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) 1858 goto out; 1859 netlink_skb_flags |= NETLINK_SKB_DST; 1860 } else { 1861 /* Paired with WRITE_ONCE() in netlink_connect() */ 1862 dst_portid = READ_ONCE(nlk->dst_portid); 1863 dst_group = READ_ONCE(nlk->dst_group); 1864 } 1865 1866 /* Paired with WRITE_ONCE() in netlink_insert() */ 1867 if (!READ_ONCE(nlk->bound)) { 1868 err = netlink_autobind(sock); 1869 if (err) 1870 goto out; 1871 } else { 1872 /* Ensure nlk is hashed and visible. */ 1873 smp_rmb(); 1874 } 1875 1876 err = -EMSGSIZE; 1877 if (len > sk->sk_sndbuf - 32) 1878 goto out; 1879 err = -ENOBUFS; 1880 skb = netlink_alloc_large_skb(len, dst_group); 1881 if (skb == NULL) 1882 goto out; 1883 1884 NETLINK_CB(skb).portid = nlk->portid; 1885 NETLINK_CB(skb).dst_group = dst_group; 1886 NETLINK_CB(skb).creds = scm.creds; 1887 NETLINK_CB(skb).flags = netlink_skb_flags; 1888 1889 err = -EFAULT; 1890 if (memcpy_from_msg(skb_put(skb, len), msg, len)) { 1891 kfree_skb(skb); 1892 goto out; 1893 } 1894 1895 err = security_netlink_send(sk, skb); 1896 if (err) { 1897 kfree_skb(skb); 1898 goto out; 1899 } 1900 1901 if (dst_group) { 1902 refcount_inc(&skb->users); 1903 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL); 1904 } 1905 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags & MSG_DONTWAIT); 1906 1907out: 1908 scm_destroy(&scm); 1909 return err; 1910} 1911 1912static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 1913 int flags) 1914{ 1915 struct scm_cookie scm; 1916 struct sock *sk = sock->sk; 1917 struct netlink_sock *nlk = nlk_sk(sk); 1918 size_t copied, max_recvmsg_len; 1919 struct sk_buff *skb, *data_skb; 1920 int err, ret; 1921 1922 if (flags & MSG_OOB) 1923 return -EOPNOTSUPP; 1924 1925 copied = 0; 1926 1927 skb = skb_recv_datagram(sk, flags, &err); 1928 if (skb == NULL) 1929 goto out; 1930 1931 data_skb = skb; 1932 1933#ifdef CONFIG_COMPAT_NETLINK_MESSAGES 1934 if (unlikely(skb_shinfo(skb)->frag_list)) { 1935 /* 1936 * If this skb has a frag_list, then here that means that we 1937 * will have to use the frag_list skb's data for compat tasks 1938 * and the regular skb's data for normal (non-compat) tasks. 1939 * 1940 * If we need to send the compat skb, assign it to the 1941 * 'data_skb' variable so that it will be used below for data 1942 * copying. We keep 'skb' for everything else, including 1943 * freeing both later. 1944 */ 1945 if (flags & MSG_CMSG_COMPAT) 1946 data_skb = skb_shinfo(skb)->frag_list; 1947 } 1948#endif 1949 1950 /* Record the max length of recvmsg() calls for future allocations */ 1951 max_recvmsg_len = max(READ_ONCE(nlk->max_recvmsg_len), len); 1952 max_recvmsg_len = min_t(size_t, max_recvmsg_len, 1953 SKB_WITH_OVERHEAD(32768)); 1954 WRITE_ONCE(nlk->max_recvmsg_len, max_recvmsg_len); 1955 1956 copied = data_skb->len; 1957 if (len < copied) { 1958 msg->msg_flags |= MSG_TRUNC; 1959 copied = len; 1960 } 1961 1962 err = skb_copy_datagram_msg(data_skb, 0, msg, copied); 1963 1964 if (msg->msg_name) { 1965 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); 1966 addr->nl_family = AF_NETLINK; 1967 addr->nl_pad = 0; 1968 addr->nl_pid = NETLINK_CB(skb).portid; 1969 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); 1970 msg->msg_namelen = sizeof(*addr); 1971 } 1972 1973 if (nlk_test_bit(RECV_PKTINFO, sk)) 1974 netlink_cmsg_recv_pktinfo(msg, skb); 1975 if (nlk_test_bit(LISTEN_ALL_NSID, sk)) 1976 netlink_cmsg_listen_all_nsid(sk, msg, skb); 1977 1978 memset(&scm, 0, sizeof(scm)); 1979 scm.creds = *NETLINK_CREDS(skb); 1980 if (flags & MSG_TRUNC) 1981 copied = data_skb->len; 1982 1983 skb_free_datagram(sk, skb); 1984 1985 if (READ_ONCE(nlk->cb_running) && 1986 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { 1987 ret = netlink_dump(sk, false); 1988 if (ret) { 1989 WRITE_ONCE(sk->sk_err, -ret); 1990 sk_error_report(sk); 1991 } 1992 } 1993 1994 scm_recv(sock, msg, &scm, flags); 1995out: 1996 netlink_rcv_wake(sk); 1997 return err ? : copied; 1998} 1999 2000static void netlink_data_ready(struct sock *sk) 2001{ 2002 BUG(); 2003} 2004 2005/* 2006 * We export these functions to other modules. They provide a 2007 * complete set of kernel non-blocking support for message 2008 * queueing. 2009 */ 2010 2011struct sock * 2012__netlink_kernel_create(struct net *net, int unit, struct module *module, 2013 struct netlink_kernel_cfg *cfg) 2014{ 2015 struct socket *sock; 2016 struct sock *sk; 2017 struct netlink_sock *nlk; 2018 struct listeners *listeners = NULL; 2019 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL; 2020 unsigned int groups; 2021 2022 BUG_ON(!nl_table); 2023 2024 if (unit < 0 || unit >= MAX_LINKS) 2025 return NULL; 2026 2027 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) 2028 return NULL; 2029 2030 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0) 2031 goto out_sock_release_nosk; 2032 2033 sk = sock->sk; 2034 2035 if (!cfg || cfg->groups < 32) 2036 groups = 32; 2037 else 2038 groups = cfg->groups; 2039 2040 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2041 if (!listeners) 2042 goto out_sock_release; 2043 2044 sk->sk_data_ready = netlink_data_ready; 2045 if (cfg && cfg->input) 2046 nlk_sk(sk)->netlink_rcv = cfg->input; 2047 2048 if (netlink_insert(sk, 0)) 2049 goto out_sock_release; 2050 2051 nlk = nlk_sk(sk); 2052 set_bit(NETLINK_F_KERNEL_SOCKET, &nlk->flags); 2053 2054 netlink_table_grab(); 2055 if (!nl_table[unit].registered) { 2056 nl_table[unit].groups = groups; 2057 rcu_assign_pointer(nl_table[unit].listeners, listeners); 2058 nl_table[unit].cb_mutex = cb_mutex; 2059 nl_table[unit].module = module; 2060 if (cfg) { 2061 nl_table[unit].bind = cfg->bind; 2062 nl_table[unit].unbind = cfg->unbind; 2063 nl_table[unit].release = cfg->release; 2064 nl_table[unit].flags = cfg->flags; 2065 } 2066 nl_table[unit].registered = 1; 2067 } else { 2068 kfree(listeners); 2069 nl_table[unit].registered++; 2070 } 2071 netlink_table_ungrab(); 2072 return sk; 2073 2074out_sock_release: 2075 kfree(listeners); 2076 netlink_kernel_release(sk); 2077 return NULL; 2078 2079out_sock_release_nosk: 2080 sock_release(sock); 2081 return NULL; 2082} 2083EXPORT_SYMBOL(__netlink_kernel_create); 2084 2085void 2086netlink_kernel_release(struct sock *sk) 2087{ 2088 if (sk == NULL || sk->sk_socket == NULL) 2089 return; 2090 2091 sock_release(sk->sk_socket); 2092} 2093EXPORT_SYMBOL(netlink_kernel_release); 2094 2095int __netlink_change_ngroups(struct sock *sk, unsigned int groups) 2096{ 2097 struct listeners *new, *old; 2098 struct netlink_table *tbl = &nl_table[sk->sk_protocol]; 2099 2100 if (groups < 32) 2101 groups = 32; 2102 2103 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) { 2104 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC); 2105 if (!new) 2106 return -ENOMEM; 2107 old = nl_deref_protected(tbl->listeners); 2108 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups)); 2109 rcu_assign_pointer(tbl->listeners, new); 2110 2111 kfree_rcu(old, rcu); 2112 } 2113 tbl->groups = groups; 2114 2115 return 0; 2116} 2117 2118/** 2119 * netlink_change_ngroups - change number of multicast groups 2120 * 2121 * This changes the number of multicast groups that are available 2122 * on a certain netlink family. Note that it is not possible to 2123 * change the number of groups to below 32. Also note that it does 2124 * not implicitly call netlink_clear_multicast_users() when the 2125 * number of groups is reduced. 2126 * 2127 * @sk: The kernel netlink socket, as returned by netlink_kernel_create(). 2128 * @groups: The new number of groups. 2129 */ 2130int netlink_change_ngroups(struct sock *sk, unsigned int groups) 2131{ 2132 int err; 2133 2134 netlink_table_grab(); 2135 err = __netlink_change_ngroups(sk, groups); 2136 netlink_table_ungrab(); 2137 2138 return err; 2139} 2140 2141void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group) 2142{ 2143 struct sock *sk; 2144 struct netlink_table *tbl = &nl_table[ksk->sk_protocol]; 2145 2146 sk_for_each_bound(sk, &tbl->mc_list) 2147 netlink_update_socket_mc(nlk_sk(sk), group, 0); 2148} 2149 2150struct nlmsghdr * 2151__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags) 2152{ 2153 struct nlmsghdr *nlh; 2154 int size = nlmsg_msg_size(len); 2155 2156 nlh = skb_put(skb, NLMSG_ALIGN(size)); 2157 nlh->nlmsg_type = type; 2158 nlh->nlmsg_len = size; 2159 nlh->nlmsg_flags = flags; 2160 nlh->nlmsg_pid = portid; 2161 nlh->nlmsg_seq = seq; 2162 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0) 2163 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size); 2164 return nlh; 2165} 2166EXPORT_SYMBOL(__nlmsg_put); 2167 2168/* 2169 * It looks a bit ugly. 2170 * It would be better to create kernel thread. 2171 */ 2172 2173static int netlink_dump_done(struct netlink_sock *nlk, struct sk_buff *skb, 2174 struct netlink_callback *cb, 2175 struct netlink_ext_ack *extack) 2176{ 2177 struct nlmsghdr *nlh; 2178 2179 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(nlk->dump_done_errno), 2180 NLM_F_MULTI | cb->answer_flags); 2181 if (WARN_ON(!nlh)) 2182 return -ENOBUFS; 2183 2184 nl_dump_check_consistent(cb, nlh); 2185 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, sizeof(nlk->dump_done_errno)); 2186 2187 if (extack->_msg && test_bit(NETLINK_F_EXT_ACK, &nlk->flags)) { 2188 nlh->nlmsg_flags |= NLM_F_ACK_TLVS; 2189 if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg)) 2190 nlmsg_end(skb, nlh); 2191 } 2192 2193 return 0; 2194} 2195 2196static int netlink_dump(struct sock *sk, bool lock_taken) 2197{ 2198 struct netlink_sock *nlk = nlk_sk(sk); 2199 struct netlink_ext_ack extack = {}; 2200 struct netlink_callback *cb; 2201 struct sk_buff *skb = NULL; 2202 size_t max_recvmsg_len; 2203 struct module *module; 2204 int err = -ENOBUFS; 2205 int alloc_min_size; 2206 int alloc_size; 2207 2208 if (!lock_taken) 2209 mutex_lock(&nlk->nl_cb_mutex); 2210 if (!nlk->cb_running) { 2211 err = -EINVAL; 2212 goto errout_skb; 2213 } 2214 2215 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) 2216 goto errout_skb; 2217 2218 /* NLMSG_GOODSIZE is small to avoid high order allocations being 2219 * required, but it makes sense to _attempt_ a 16K bytes allocation 2220 * to reduce number of system calls on dump operations, if user 2221 * ever provided a big enough buffer. 2222 */ 2223 cb = &nlk->cb; 2224 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); 2225 2226 max_recvmsg_len = READ_ONCE(nlk->max_recvmsg_len); 2227 if (alloc_min_size < max_recvmsg_len) { 2228 alloc_size = max_recvmsg_len; 2229 skb = alloc_skb(alloc_size, 2230 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) | 2231 __GFP_NOWARN | __GFP_NORETRY); 2232 } 2233 if (!skb) { 2234 alloc_size = alloc_min_size; 2235 skb = alloc_skb(alloc_size, GFP_KERNEL); 2236 } 2237 if (!skb) 2238 goto errout_skb; 2239 2240 /* Trim skb to allocated size. User is expected to provide buffer as 2241 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at 2242 * netlink_recvmsg())). dump will pack as many smaller messages as 2243 * could fit within the allocated skb. skb is typically allocated 2244 * with larger space than required (could be as much as near 2x the 2245 * requested size with align to next power of 2 approach). Allowing 2246 * dump to use the excess space makes it difficult for a user to have a 2247 * reasonable static buffer based on the expected largest dump of a 2248 * single netdev. The outcome is MSG_TRUNC error. 2249 */ 2250 skb_reserve(skb, skb_tailroom(skb) - alloc_size); 2251 2252 /* Make sure malicious BPF programs can not read unitialized memory 2253 * from skb->head -> skb->data 2254 */ 2255 skb_reset_network_header(skb); 2256 skb_reset_mac_header(skb); 2257 2258 netlink_skb_set_owner_r(skb, sk); 2259 2260 if (nlk->dump_done_errno > 0) { 2261 struct mutex *extra_mutex = nlk->dump_cb_mutex; 2262 2263 cb->extack = &extack; 2264 2265 if (cb->flags & RTNL_FLAG_DUMP_UNLOCKED) 2266 extra_mutex = NULL; 2267 if (extra_mutex) 2268 mutex_lock(extra_mutex); 2269 nlk->dump_done_errno = cb->dump(skb, cb); 2270 if (extra_mutex) 2271 mutex_unlock(extra_mutex); 2272 2273 /* EMSGSIZE plus something already in the skb means 2274 * that there's more to dump but current skb has filled up. 2275 * If the callback really wants to return EMSGSIZE to user space 2276 * it needs to do so again, on the next cb->dump() call, 2277 * without putting data in the skb. 2278 */ 2279 if (nlk->dump_done_errno == -EMSGSIZE && skb->len) 2280 nlk->dump_done_errno = skb->len; 2281 2282 cb->extack = NULL; 2283 } 2284 2285 if (nlk->dump_done_errno > 0 || 2286 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) { 2287 mutex_unlock(&nlk->nl_cb_mutex); 2288 2289 if (sk_filter(sk, skb)) 2290 kfree_skb(skb); 2291 else 2292 __netlink_sendskb(sk, skb); 2293 return 0; 2294 } 2295 2296 if (netlink_dump_done(nlk, skb, cb, &extack)) 2297 goto errout_skb; 2298 2299#ifdef CONFIG_COMPAT_NETLINK_MESSAGES 2300 /* frag_list skb's data is used for compat tasks 2301 * and the regular skb's data for normal (non-compat) tasks. 2302 * See netlink_recvmsg(). 2303 */ 2304 if (unlikely(skb_shinfo(skb)->frag_list)) { 2305 if (netlink_dump_done(nlk, skb_shinfo(skb)->frag_list, cb, &extack)) 2306 goto errout_skb; 2307 } 2308#endif 2309 2310 if (sk_filter(sk, skb)) 2311 kfree_skb(skb); 2312 else 2313 __netlink_sendskb(sk, skb); 2314 2315 if (cb->done) 2316 cb->done(cb); 2317 2318 WRITE_ONCE(nlk->cb_running, false); 2319 module = cb->module; 2320 skb = cb->skb; 2321 mutex_unlock(&nlk->nl_cb_mutex); 2322 module_put(module); 2323 consume_skb(skb); 2324 return 0; 2325 2326errout_skb: 2327 mutex_unlock(&nlk->nl_cb_mutex); 2328 kfree_skb(skb); 2329 return err; 2330} 2331 2332int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 2333 const struct nlmsghdr *nlh, 2334 struct netlink_dump_control *control) 2335{ 2336 struct netlink_callback *cb; 2337 struct netlink_sock *nlk; 2338 struct sock *sk; 2339 int ret; 2340 2341 refcount_inc(&skb->users); 2342 2343 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid); 2344 if (sk == NULL) { 2345 ret = -ECONNREFUSED; 2346 goto error_free; 2347 } 2348 2349 nlk = nlk_sk(sk); 2350 mutex_lock(&nlk->nl_cb_mutex); 2351 /* A dump is in progress... */ 2352 if (nlk->cb_running) { 2353 ret = -EBUSY; 2354 goto error_unlock; 2355 } 2356 /* add reference of module which cb->dump belongs to */ 2357 if (!try_module_get(control->module)) { 2358 ret = -EPROTONOSUPPORT; 2359 goto error_unlock; 2360 } 2361 2362 cb = &nlk->cb; 2363 memset(cb, 0, sizeof(*cb)); 2364 cb->dump = control->dump; 2365 cb->done = control->done; 2366 cb->nlh = nlh; 2367 cb->data = control->data; 2368 cb->module = control->module; 2369 cb->min_dump_alloc = control->min_dump_alloc; 2370 cb->flags = control->flags; 2371 cb->skb = skb; 2372 2373 cb->strict_check = nlk_test_bit(STRICT_CHK, NETLINK_CB(skb).sk); 2374 2375 if (control->start) { 2376 cb->extack = control->extack; 2377 ret = control->start(cb); 2378 cb->extack = NULL; 2379 if (ret) 2380 goto error_put; 2381 } 2382 2383 WRITE_ONCE(nlk->cb_running, true); 2384 nlk->dump_done_errno = INT_MAX; 2385 2386 ret = netlink_dump(sk, true); 2387 2388 sock_put(sk); 2389 2390 if (ret) 2391 return ret; 2392 2393 /* We successfully started a dump, by returning -EINTR we 2394 * signal not to send ACK even if it was requested. 2395 */ 2396 return -EINTR; 2397 2398error_put: 2399 module_put(control->module); 2400error_unlock: 2401 sock_put(sk); 2402 mutex_unlock(&nlk->nl_cb_mutex); 2403error_free: 2404 kfree_skb(skb); 2405 return ret; 2406} 2407EXPORT_SYMBOL(__netlink_dump_start); 2408 2409static size_t 2410netlink_ack_tlv_len(struct netlink_sock *nlk, int err, 2411 const struct netlink_ext_ack *extack) 2412{ 2413 size_t tlvlen; 2414 2415 if (!extack || !test_bit(NETLINK_F_EXT_ACK, &nlk->flags)) 2416 return 0; 2417 2418 tlvlen = 0; 2419 if (extack->_msg) 2420 tlvlen += nla_total_size(strlen(extack->_msg) + 1); 2421 if (extack->cookie_len) 2422 tlvlen += nla_total_size(extack->cookie_len); 2423 2424 /* Following attributes are only reported as error (not warning) */ 2425 if (!err) 2426 return tlvlen; 2427 2428 if (extack->bad_attr) 2429 tlvlen += nla_total_size(sizeof(u32)); 2430 if (extack->policy) 2431 tlvlen += netlink_policy_dump_attr_size_estimate(extack->policy); 2432 if (extack->miss_type) 2433 tlvlen += nla_total_size(sizeof(u32)); 2434 if (extack->miss_nest) 2435 tlvlen += nla_total_size(sizeof(u32)); 2436 2437 return tlvlen; 2438} 2439 2440static void 2441netlink_ack_tlv_fill(struct sk_buff *in_skb, struct sk_buff *skb, 2442 struct nlmsghdr *nlh, int err, 2443 const struct netlink_ext_ack *extack) 2444{ 2445 if (extack->_msg) 2446 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg)); 2447 if (extack->cookie_len) 2448 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE, 2449 extack->cookie_len, extack->cookie)); 2450 2451 if (!err) 2452 return; 2453 2454 if (extack->bad_attr && 2455 !WARN_ON((u8 *)extack->bad_attr < in_skb->data || 2456 (u8 *)extack->bad_attr >= in_skb->data + in_skb->len)) 2457 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS, 2458 (u8 *)extack->bad_attr - (u8 *)nlh)); 2459 if (extack->policy) 2460 netlink_policy_dump_write_attr(skb, extack->policy, 2461 NLMSGERR_ATTR_POLICY); 2462 if (extack->miss_type) 2463 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_TYPE, 2464 extack->miss_type)); 2465 if (extack->miss_nest && 2466 !WARN_ON((u8 *)extack->miss_nest < in_skb->data || 2467 (u8 *)extack->miss_nest > in_skb->data + in_skb->len)) 2468 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_NEST, 2469 (u8 *)extack->miss_nest - (u8 *)nlh)); 2470} 2471 2472void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, 2473 const struct netlink_ext_ack *extack) 2474{ 2475 struct sk_buff *skb; 2476 struct nlmsghdr *rep; 2477 struct nlmsgerr *errmsg; 2478 size_t payload = sizeof(*errmsg); 2479 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk); 2480 unsigned int flags = 0; 2481 size_t tlvlen; 2482 2483 /* Error messages get the original request appened, unless the user 2484 * requests to cap the error message, and get extra error data if 2485 * requested. 2486 */ 2487 if (err && !test_bit(NETLINK_F_CAP_ACK, &nlk->flags)) 2488 payload += nlmsg_len(nlh); 2489 else 2490 flags |= NLM_F_CAPPED; 2491 2492 tlvlen = netlink_ack_tlv_len(nlk, err, extack); 2493 if (tlvlen) 2494 flags |= NLM_F_ACK_TLVS; 2495 2496 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL); 2497 if (!skb) 2498 goto err_skb; 2499 2500 rep = nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, 2501 NLMSG_ERROR, sizeof(*errmsg), flags); 2502 if (!rep) 2503 goto err_bad_put; 2504 errmsg = nlmsg_data(rep); 2505 errmsg->error = err; 2506 errmsg->msg = *nlh; 2507 2508 if (!(flags & NLM_F_CAPPED)) { 2509 if (!nlmsg_append(skb, nlmsg_len(nlh))) 2510 goto err_bad_put; 2511 2512 memcpy(nlmsg_data(&errmsg->msg), nlmsg_data(nlh), 2513 nlmsg_len(nlh)); 2514 } 2515 2516 if (tlvlen) 2517 netlink_ack_tlv_fill(in_skb, skb, nlh, err, extack); 2518 2519 nlmsg_end(skb, rep); 2520 2521 nlmsg_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid); 2522 2523 return; 2524 2525err_bad_put: 2526 nlmsg_free(skb); 2527err_skb: 2528 WRITE_ONCE(NETLINK_CB(in_skb).sk->sk_err, ENOBUFS); 2529 sk_error_report(NETLINK_CB(in_skb).sk); 2530} 2531EXPORT_SYMBOL(netlink_ack); 2532 2533int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, 2534 struct nlmsghdr *, 2535 struct netlink_ext_ack *)) 2536{ 2537 struct netlink_ext_ack extack; 2538 struct nlmsghdr *nlh; 2539 int err; 2540 2541 while (skb->len >= nlmsg_total_size(0)) { 2542 int msglen; 2543 2544 memset(&extack, 0, sizeof(extack)); 2545 nlh = nlmsg_hdr(skb); 2546 err = 0; 2547 2548 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) 2549 return 0; 2550 2551 /* Only requests are handled by the kernel */ 2552 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) 2553 goto ack; 2554 2555 /* Skip control messages */ 2556 if (nlh->nlmsg_type < NLMSG_MIN_TYPE) 2557 goto ack; 2558 2559 err = cb(skb, nlh, &extack); 2560 if (err == -EINTR) 2561 goto skip; 2562 2563ack: 2564 if (nlh->nlmsg_flags & NLM_F_ACK || err) 2565 netlink_ack(skb, nlh, err, &extack); 2566 2567skip: 2568 msglen = NLMSG_ALIGN(nlh->nlmsg_len); 2569 if (msglen > skb->len) 2570 msglen = skb->len; 2571 skb_pull(skb, msglen); 2572 } 2573 2574 return 0; 2575} 2576EXPORT_SYMBOL(netlink_rcv_skb); 2577 2578/** 2579 * nlmsg_notify - send a notification netlink message 2580 * @sk: netlink socket to use 2581 * @skb: notification message 2582 * @portid: destination netlink portid for reports or 0 2583 * @group: destination multicast group or 0 2584 * @report: 1 to report back, 0 to disable 2585 * @flags: allocation flags 2586 */ 2587int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid, 2588 unsigned int group, int report, gfp_t flags) 2589{ 2590 int err = 0; 2591 2592 if (group) { 2593 int exclude_portid = 0; 2594 2595 if (report) { 2596 refcount_inc(&skb->users); 2597 exclude_portid = portid; 2598 } 2599 2600 /* errors reported via destination sk->sk_err, but propagate 2601 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */ 2602 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags); 2603 if (err == -ESRCH) 2604 err = 0; 2605 } 2606 2607 if (report) { 2608 int err2; 2609 2610 err2 = nlmsg_unicast(sk, skb, portid); 2611 if (!err) 2612 err = err2; 2613 } 2614 2615 return err; 2616} 2617EXPORT_SYMBOL(nlmsg_notify); 2618 2619#ifdef CONFIG_PROC_FS 2620struct nl_seq_iter { 2621 struct seq_net_private p; 2622 struct rhashtable_iter hti; 2623 int link; 2624}; 2625 2626static void netlink_walk_start(struct nl_seq_iter *iter) 2627{ 2628 rhashtable_walk_enter(&nl_table[iter->link].hash, &iter->hti); 2629 rhashtable_walk_start(&iter->hti); 2630} 2631 2632static void netlink_walk_stop(struct nl_seq_iter *iter) 2633{ 2634 rhashtable_walk_stop(&iter->hti); 2635 rhashtable_walk_exit(&iter->hti); 2636} 2637 2638static void *__netlink_seq_next(struct seq_file *seq) 2639{ 2640 struct nl_seq_iter *iter = seq->private; 2641 struct netlink_sock *nlk; 2642 2643 do { 2644 for (;;) { 2645 nlk = rhashtable_walk_next(&iter->hti); 2646 2647 if (IS_ERR(nlk)) { 2648 if (PTR_ERR(nlk) == -EAGAIN) 2649 continue; 2650 2651 return nlk; 2652 } 2653 2654 if (nlk) 2655 break; 2656 2657 netlink_walk_stop(iter); 2658 if (++iter->link >= MAX_LINKS) 2659 return NULL; 2660 2661 netlink_walk_start(iter); 2662 } 2663 } while (sock_net(&nlk->sk) != seq_file_net(seq)); 2664 2665 return nlk; 2666} 2667 2668static void *netlink_seq_start(struct seq_file *seq, loff_t *posp) 2669 __acquires(RCU) 2670{ 2671 struct nl_seq_iter *iter = seq->private; 2672 void *obj = SEQ_START_TOKEN; 2673 loff_t pos; 2674 2675 iter->link = 0; 2676 2677 netlink_walk_start(iter); 2678 2679 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--) 2680 obj = __netlink_seq_next(seq); 2681 2682 return obj; 2683} 2684 2685static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2686{ 2687 ++*pos; 2688 return __netlink_seq_next(seq); 2689} 2690 2691static void netlink_native_seq_stop(struct seq_file *seq, void *v) 2692{ 2693 struct nl_seq_iter *iter = seq->private; 2694 2695 if (iter->link >= MAX_LINKS) 2696 return; 2697 2698 netlink_walk_stop(iter); 2699} 2700 2701 2702static int netlink_native_seq_show(struct seq_file *seq, void *v) 2703{ 2704 if (v == SEQ_START_TOKEN) { 2705 seq_puts(seq, 2706 "sk Eth Pid Groups " 2707 "Rmem Wmem Dump Locks Drops Inode\n"); 2708 } else { 2709 struct sock *s = v; 2710 struct netlink_sock *nlk = nlk_sk(s); 2711 2712 seq_printf(seq, "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8u %-8lu\n", 2713 s, 2714 s->sk_protocol, 2715 nlk->portid, 2716 nlk->groups ? (u32)nlk->groups[0] : 0, 2717 sk_rmem_alloc_get(s), 2718 sk_wmem_alloc_get(s), 2719 READ_ONCE(nlk->cb_running), 2720 refcount_read(&s->sk_refcnt), 2721 atomic_read(&s->sk_drops), 2722 sock_i_ino(s) 2723 ); 2724 2725 } 2726 return 0; 2727} 2728 2729#ifdef CONFIG_BPF_SYSCALL 2730struct bpf_iter__netlink { 2731 __bpf_md_ptr(struct bpf_iter_meta *, meta); 2732 __bpf_md_ptr(struct netlink_sock *, sk); 2733}; 2734 2735DEFINE_BPF_ITER_FUNC(netlink, struct bpf_iter_meta *meta, struct netlink_sock *sk) 2736 2737static int netlink_prog_seq_show(struct bpf_prog *prog, 2738 struct bpf_iter_meta *meta, 2739 void *v) 2740{ 2741 struct bpf_iter__netlink ctx; 2742 2743 meta->seq_num--; /* skip SEQ_START_TOKEN */ 2744 ctx.meta = meta; 2745 ctx.sk = nlk_sk((struct sock *)v); 2746 return bpf_iter_run_prog(prog, &ctx); 2747} 2748 2749static int netlink_seq_show(struct seq_file *seq, void *v) 2750{ 2751 struct bpf_iter_meta meta; 2752 struct bpf_prog *prog; 2753 2754 meta.seq = seq; 2755 prog = bpf_iter_get_info(&meta, false); 2756 if (!prog) 2757 return netlink_native_seq_show(seq, v); 2758 2759 if (v != SEQ_START_TOKEN) 2760 return netlink_prog_seq_show(prog, &meta, v); 2761 2762 return 0; 2763} 2764 2765static void netlink_seq_stop(struct seq_file *seq, void *v) 2766{ 2767 struct bpf_iter_meta meta; 2768 struct bpf_prog *prog; 2769 2770 if (!v) { 2771 meta.seq = seq; 2772 prog = bpf_iter_get_info(&meta, true); 2773 if (prog) 2774 (void)netlink_prog_seq_show(prog, &meta, v); 2775 } 2776 2777 netlink_native_seq_stop(seq, v); 2778} 2779#else 2780static int netlink_seq_show(struct seq_file *seq, void *v) 2781{ 2782 return netlink_native_seq_show(seq, v); 2783} 2784 2785static void netlink_seq_stop(struct seq_file *seq, void *v) 2786{ 2787 netlink_native_seq_stop(seq, v); 2788} 2789#endif 2790 2791static const struct seq_operations netlink_seq_ops = { 2792 .start = netlink_seq_start, 2793 .next = netlink_seq_next, 2794 .stop = netlink_seq_stop, 2795 .show = netlink_seq_show, 2796}; 2797#endif 2798 2799int netlink_register_notifier(struct notifier_block *nb) 2800{ 2801 return blocking_notifier_chain_register(&netlink_chain, nb); 2802} 2803EXPORT_SYMBOL(netlink_register_notifier); 2804 2805int netlink_unregister_notifier(struct notifier_block *nb) 2806{ 2807 return blocking_notifier_chain_unregister(&netlink_chain, nb); 2808} 2809EXPORT_SYMBOL(netlink_unregister_notifier); 2810 2811static const struct proto_ops netlink_ops = { 2812 .family = PF_NETLINK, 2813 .owner = THIS_MODULE, 2814 .release = netlink_release, 2815 .bind = netlink_bind, 2816 .connect = netlink_connect, 2817 .socketpair = sock_no_socketpair, 2818 .accept = sock_no_accept, 2819 .getname = netlink_getname, 2820 .poll = datagram_poll, 2821 .ioctl = netlink_ioctl, 2822 .listen = sock_no_listen, 2823 .shutdown = sock_no_shutdown, 2824 .setsockopt = netlink_setsockopt, 2825 .getsockopt = netlink_getsockopt, 2826 .sendmsg = netlink_sendmsg, 2827 .recvmsg = netlink_recvmsg, 2828 .mmap = sock_no_mmap, 2829}; 2830 2831static const struct net_proto_family netlink_family_ops = { 2832 .family = PF_NETLINK, 2833 .create = netlink_create, 2834 .owner = THIS_MODULE, /* for consistency 8) */ 2835}; 2836 2837static int __net_init netlink_net_init(struct net *net) 2838{ 2839#ifdef CONFIG_PROC_FS 2840 if (!proc_create_net("netlink", 0, net->proc_net, &netlink_seq_ops, 2841 sizeof(struct nl_seq_iter))) 2842 return -ENOMEM; 2843#endif 2844 return 0; 2845} 2846 2847static void __net_exit netlink_net_exit(struct net *net) 2848{ 2849#ifdef CONFIG_PROC_FS 2850 remove_proc_entry("netlink", net->proc_net); 2851#endif 2852} 2853 2854static void __init netlink_add_usersock_entry(void) 2855{ 2856 struct listeners *listeners; 2857 int groups = 32; 2858 2859 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); 2860 if (!listeners) 2861 panic("netlink_add_usersock_entry: Cannot allocate listeners\n"); 2862 2863 netlink_table_grab(); 2864 2865 nl_table[NETLINK_USERSOCK].groups = groups; 2866 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners); 2867 nl_table[NETLINK_USERSOCK].module = THIS_MODULE; 2868 nl_table[NETLINK_USERSOCK].registered = 1; 2869 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND; 2870 2871 netlink_table_ungrab(); 2872} 2873 2874static struct pernet_operations __net_initdata netlink_net_ops = { 2875 .init = netlink_net_init, 2876 .exit = netlink_net_exit, 2877}; 2878 2879static inline u32 netlink_hash(const void *data, u32 len, u32 seed) 2880{ 2881 const struct netlink_sock *nlk = data; 2882 struct netlink_compare_arg arg; 2883 2884 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid); 2885 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed); 2886} 2887 2888static const struct rhashtable_params netlink_rhashtable_params = { 2889 .head_offset = offsetof(struct netlink_sock, node), 2890 .key_len = netlink_compare_arg_len, 2891 .obj_hashfn = netlink_hash, 2892 .obj_cmpfn = netlink_compare, 2893 .automatic_shrinking = true, 2894}; 2895 2896#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 2897BTF_ID_LIST(btf_netlink_sock_id) 2898BTF_ID(struct, netlink_sock) 2899 2900static const struct bpf_iter_seq_info netlink_seq_info = { 2901 .seq_ops = &netlink_seq_ops, 2902 .init_seq_private = bpf_iter_init_seq_net, 2903 .fini_seq_private = bpf_iter_fini_seq_net, 2904 .seq_priv_size = sizeof(struct nl_seq_iter), 2905}; 2906 2907static struct bpf_iter_reg netlink_reg_info = { 2908 .target = "netlink", 2909 .ctx_arg_info_size = 1, 2910 .ctx_arg_info = { 2911 { offsetof(struct bpf_iter__netlink, sk), 2912 PTR_TO_BTF_ID_OR_NULL }, 2913 }, 2914 .seq_info = &netlink_seq_info, 2915}; 2916 2917static int __init bpf_iter_register(void) 2918{ 2919 netlink_reg_info.ctx_arg_info[0].btf_id = *btf_netlink_sock_id; 2920 return bpf_iter_reg_target(&netlink_reg_info); 2921} 2922#endif 2923 2924static int __init netlink_proto_init(void) 2925{ 2926 int i; 2927 int err = proto_register(&netlink_proto, 0); 2928 2929 if (err != 0) 2930 goto out; 2931 2932#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 2933 err = bpf_iter_register(); 2934 if (err) 2935 goto out; 2936#endif 2937 2938 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof_field(struct sk_buff, cb)); 2939 2940 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); 2941 if (!nl_table) 2942 goto panic; 2943 2944 for (i = 0; i < MAX_LINKS; i++) { 2945 if (rhashtable_init(&nl_table[i].hash, 2946 &netlink_rhashtable_params) < 0) { 2947 while (--i > 0) 2948 rhashtable_destroy(&nl_table[i].hash); 2949 kfree(nl_table); 2950 goto panic; 2951 } 2952 } 2953 2954 netlink_add_usersock_entry(); 2955 2956 sock_register(&netlink_family_ops); 2957 register_pernet_subsys(&netlink_net_ops); 2958 register_pernet_subsys(&netlink_tap_net_ops); 2959 /* The netlink device handler may be needed early. */ 2960 rtnetlink_init(); 2961out: 2962 return err; 2963panic: 2964 panic("netlink_init: Cannot allocate nl_table\n"); 2965} 2966 2967core_initcall(netlink_proto_init); 2968