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/net_namespace.h>
63#include <linux/nospec.h>
64#include <linux/btf_ids.h>
65
66#include <net/net_namespace.h>
67#include <net/netns/generic.h>
68#include <net/sock.h>
69#include <net/scm.h>
70#include <net/netlink.h>
71#define CREATE_TRACE_POINTS
72#include <trace/events/netlink.h>
73
74#include "af_netlink.h"
75#include "genetlink.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(size: len, priority: 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(skb: new, data: 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(dev: nt->dev);
195 struct netlink_tap_net *nn = net_generic(net, id: netlink_tap_net_id);
196
197 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
198 return -EINVAL;
199
200 mutex_lock(lock: &nn->netlink_tap_lock);
201 list_add_rcu(new: &nt->list, head: &nn->netlink_tap_all);
202 mutex_unlock(lock: &nn->netlink_tap_lock);
203
204 __module_get(module: 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(dev: nt->dev);
213 struct netlink_tap_net *nn = net_generic(net, id: netlink_tap_net_id);
214 bool found = false;
215 struct netlink_tap *tmp;
216
217 mutex_lock(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(entry: &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(lock: &nn->netlink_tap_lock);
230
231 if (found)
232 module_put(module: 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, id: netlink_tap_net_id);
251
252 INIT_LIST_HEAD(list: &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(net1: dev_net(dev), net2: sock_net(sk)))
293 return 0;
294
295 dev_hold(dev);
296
297 if (is_vmalloc_addr(x: 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(skb: nskb);
307 ret = dev_queue_xmit(skb: 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, dev: 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, id: 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(sk: dst) && netlink_is_kernel(sk: src)))
347 netlink_deliver_tap(net: sock_net(sk: 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 addr: &nlk_sk(sk)->state)) {
355 WRITE_ONCE(sk->sk_err, ENOBUFS);
356 sk_error_report(sk);
357 }
358 }
359 sk_drops_inc(sk);
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(list: &sk->sk_receive_queue))
367 clear_bit(NETLINK_S_CONGESTED, addr: &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(x: skb->head)) {
375 if (!skb->cloned ||
376 !atomic_dec_return(v: &(skb_shinfo(skb)->dataref)))
377 vfree_atomic(addr: 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 sk_mem_charge(sk, size: skb->truesize);
391}
392
393static void netlink_sock_destruct(struct sock *sk)
394{
395 skb_queue_purge(list: &sk->sk_receive_queue);
396
397 if (!sock_flag(sk, flag: SOCK_DEAD)) {
398 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
399 return;
400 }
401
402 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
403 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
404 WARN_ON(nlk_sk(sk)->groups);
405}
406
407/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
408 * SMP. Look, when several writers sleep and reader wakes them up, all but one
409 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
410 * this, _but_ remember, it adds useless work on UP machines.
411 */
412
413void netlink_table_grab(void)
414 __acquires(nl_table_lock)
415{
416 might_sleep();
417
418 write_lock_irq(&nl_table_lock);
419
420 if (atomic_read(v: &nl_table_users)) {
421 DECLARE_WAITQUEUE(wait, current);
422
423 add_wait_queue_exclusive(wq_head: &nl_table_wait, wq_entry: &wait);
424 for (;;) {
425 set_current_state(TASK_UNINTERRUPTIBLE);
426 if (atomic_read(v: &nl_table_users) == 0)
427 break;
428 write_unlock_irq(&nl_table_lock);
429 schedule();
430 write_lock_irq(&nl_table_lock);
431 }
432
433 __set_current_state(TASK_RUNNING);
434 remove_wait_queue(wq_head: &nl_table_wait, wq_entry: &wait);
435 }
436}
437
438void netlink_table_ungrab(void)
439 __releases(nl_table_lock)
440{
441 write_unlock_irq(&nl_table_lock);
442 wake_up(&nl_table_wait);
443}
444
445static inline void
446netlink_lock_table(void)
447{
448 unsigned long flags;
449
450 /* read_lock() synchronizes us to netlink_table_grab */
451
452 read_lock_irqsave(&nl_table_lock, flags);
453 atomic_inc(v: &nl_table_users);
454 read_unlock_irqrestore(&nl_table_lock, flags);
455}
456
457static inline void
458netlink_unlock_table(void)
459{
460 if (atomic_dec_and_test(v: &nl_table_users))
461 wake_up(&nl_table_wait);
462}
463
464struct netlink_compare_arg
465{
466 possible_net_t pnet;
467 u32 portid;
468};
469
470/* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
471#define netlink_compare_arg_len \
472 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
473
474static inline int netlink_compare(struct rhashtable_compare_arg *arg,
475 const void *ptr)
476{
477 const struct netlink_compare_arg *x = arg->key;
478 const struct netlink_sock *nlk = ptr;
479
480 return nlk->portid != x->portid ||
481 !net_eq(net1: sock_net(sk: &nlk->sk), net2: read_pnet(pnet: &x->pnet));
482}
483
484static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
485 struct net *net, u32 portid)
486{
487 memset(s: arg, c: 0, n: sizeof(*arg));
488 write_pnet(pnet: &arg->pnet, net);
489 arg->portid = portid;
490}
491
492static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
493 struct net *net)
494{
495 struct netlink_compare_arg arg;
496
497 netlink_compare_arg_init(arg: &arg, net, portid);
498 return rhashtable_lookup_fast(ht: &table->hash, key: &arg,
499 params: netlink_rhashtable_params);
500}
501
502static int __netlink_insert(struct netlink_table *table, struct sock *sk)
503{
504 struct netlink_compare_arg arg;
505
506 netlink_compare_arg_init(arg: &arg, net: sock_net(sk), portid: nlk_sk(sk)->portid);
507 return rhashtable_lookup_insert_key(ht: &table->hash, key: &arg,
508 obj: &nlk_sk(sk)->node,
509 params: netlink_rhashtable_params);
510}
511
512static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
513{
514 struct netlink_table *table = &nl_table[protocol];
515 struct sock *sk;
516
517 rcu_read_lock();
518 sk = __netlink_lookup(table, portid, net);
519 if (sk)
520 sock_hold(sk);
521 rcu_read_unlock();
522
523 return sk;
524}
525
526static const struct proto_ops netlink_ops;
527
528static void
529netlink_update_listeners(struct sock *sk)
530{
531 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
532 unsigned long mask;
533 unsigned int i;
534 struct listeners *listeners;
535
536 listeners = nl_deref_protected(tbl->listeners);
537 if (!listeners)
538 return;
539
540 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
541 mask = 0;
542 sk_for_each_bound(sk, &tbl->mc_list) {
543 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
544 mask |= nlk_sk(sk)->groups[i];
545 }
546 listeners->masks[i] = mask;
547 }
548 /* this function is only called with the netlink table "grabbed", which
549 * makes sure updates are visible before bind or setsockopt return. */
550}
551
552static int netlink_insert(struct sock *sk, u32 portid)
553{
554 struct netlink_table *table = &nl_table[sk->sk_protocol];
555 int err;
556
557 lock_sock(sk);
558
559 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
560 if (nlk_sk(sk)->bound)
561 goto err;
562
563 /* portid can be read locklessly from netlink_getname(). */
564 WRITE_ONCE(nlk_sk(sk)->portid, portid);
565
566 sock_hold(sk);
567
568 err = __netlink_insert(table, sk);
569 if (err) {
570 /* In case the hashtable backend returns with -EBUSY
571 * from here, it must not escape to the caller.
572 */
573 if (unlikely(err == -EBUSY))
574 err = -EOVERFLOW;
575 if (err == -EEXIST)
576 err = -EADDRINUSE;
577 sock_put(sk);
578 goto err;
579 }
580
581 /* We need to ensure that the socket is hashed and visible. */
582 smp_wmb();
583 /* Paired with lockless reads from netlink_bind(),
584 * netlink_connect() and netlink_sendmsg().
585 */
586 WRITE_ONCE(nlk_sk(sk)->bound, portid);
587
588err:
589 release_sock(sk);
590 return err;
591}
592
593static void netlink_remove(struct sock *sk)
594{
595 struct netlink_table *table;
596
597 table = &nl_table[sk->sk_protocol];
598 if (!rhashtable_remove_fast(ht: &table->hash, obj: &nlk_sk(sk)->node,
599 params: netlink_rhashtable_params)) {
600 WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
601 __sock_put(sk);
602 }
603
604 netlink_table_grab();
605 if (nlk_sk(sk)->subscriptions) {
606 __sk_del_bind_node(sk);
607 netlink_update_listeners(sk);
608 }
609 if (sk->sk_protocol == NETLINK_GENERIC)
610 atomic_inc(v: &genl_sk_destructing_cnt);
611 netlink_table_ungrab();
612}
613
614static struct proto netlink_proto = {
615 .name = "NETLINK",
616 .owner = THIS_MODULE,
617 .obj_size = sizeof(struct netlink_sock),
618};
619
620static int __netlink_create(struct net *net, struct socket *sock,
621 int protocol, int kern)
622{
623 struct sock *sk;
624 struct netlink_sock *nlk;
625
626 sock->ops = &netlink_ops;
627
628 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, prot: &netlink_proto, kern);
629 if (!sk)
630 return -ENOMEM;
631
632 sock_init_data(sock, sk);
633
634 nlk = nlk_sk(sk);
635 mutex_init(&nlk->nl_cb_mutex);
636 lockdep_set_class_and_name(&nlk->nl_cb_mutex,
637 nlk_cb_mutex_keys + protocol,
638 nlk_cb_mutex_key_strings[protocol]);
639 init_waitqueue_head(&nlk->wait);
640
641 sk->sk_destruct = netlink_sock_destruct;
642 sk->sk_protocol = protocol;
643 return 0;
644}
645
646static int netlink_create(struct net *net, struct socket *sock, int protocol,
647 int kern)
648{
649 struct module *module = NULL;
650 struct netlink_sock *nlk;
651 int (*bind)(struct net *net, int group);
652 void (*unbind)(struct net *net, int group);
653 void (*release)(struct sock *sock, unsigned long *groups);
654 int err = 0;
655
656 sock->state = SS_UNCONNECTED;
657
658 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
659 return -ESOCKTNOSUPPORT;
660
661 if (protocol < 0 || protocol >= MAX_LINKS)
662 return -EPROTONOSUPPORT;
663 protocol = array_index_nospec(protocol, MAX_LINKS);
664
665 netlink_lock_table();
666#ifdef CONFIG_MODULES
667 if (!nl_table[protocol].registered) {
668 netlink_unlock_table();
669 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
670 netlink_lock_table();
671 }
672#endif
673 if (nl_table[protocol].registered &&
674 try_module_get(module: nl_table[protocol].module))
675 module = nl_table[protocol].module;
676 else
677 err = -EPROTONOSUPPORT;
678 bind = nl_table[protocol].bind;
679 unbind = nl_table[protocol].unbind;
680 release = nl_table[protocol].release;
681 netlink_unlock_table();
682
683 if (err < 0)
684 goto out;
685
686 err = __netlink_create(net, sock, protocol, kern);
687 if (err < 0)
688 goto out_module;
689
690 sock_prot_inuse_add(net, prot: &netlink_proto, val: 1);
691
692 nlk = nlk_sk(sk: sock->sk);
693 nlk->module = module;
694 nlk->netlink_bind = bind;
695 nlk->netlink_unbind = unbind;
696 nlk->netlink_release = release;
697out:
698 return err;
699
700out_module:
701 module_put(module);
702 goto out;
703}
704
705static void deferred_put_nlk_sk(struct rcu_head *head)
706{
707 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
708 struct sock *sk = &nlk->sk;
709
710 kfree(objp: nlk->groups);
711 nlk->groups = NULL;
712
713 if (!refcount_dec_and_test(r: &sk->sk_refcnt))
714 return;
715
716 sk_free(sk);
717}
718
719static int netlink_release(struct socket *sock)
720{
721 struct sock *sk = sock->sk;
722 struct netlink_sock *nlk;
723
724 if (!sk)
725 return 0;
726
727 netlink_remove(sk);
728 sock_orphan(sk);
729 nlk = nlk_sk(sk);
730
731 /*
732 * OK. Socket is unlinked, any packets that arrive now
733 * will be purged.
734 */
735 if (nlk->netlink_release)
736 nlk->netlink_release(sk, nlk->groups);
737
738 /* must not acquire netlink_table_lock in any way again before unbind
739 * and notifying genetlink is done as otherwise it might deadlock
740 */
741 if (nlk->netlink_unbind) {
742 int i;
743
744 for (i = 0; i < nlk->ngroups; i++)
745 if (test_bit(i, nlk->groups))
746 nlk->netlink_unbind(sock_net(sk), i + 1);
747 }
748 if (sk->sk_protocol == NETLINK_GENERIC &&
749 atomic_dec_return(v: &genl_sk_destructing_cnt) == 0)
750 wake_up(&genl_sk_destructing_waitq);
751
752 sock->sk = NULL;
753 wake_up_interruptible_all(&nlk->wait);
754
755 skb_queue_purge(list: &sk->sk_write_queue);
756
757 if (nlk->portid && nlk->bound) {
758 struct netlink_notify n = {
759 .net = sock_net(sk),
760 .protocol = sk->sk_protocol,
761 .portid = nlk->portid,
762 };
763 blocking_notifier_call_chain(nh: &netlink_chain,
764 NETLINK_URELEASE, v: &n);
765 }
766
767 /* Terminate any outstanding dump */
768 if (nlk->cb_running) {
769 if (nlk->cb.done)
770 nlk->cb.done(&nlk->cb);
771 module_put(module: nlk->cb.module);
772 kfree_skb(skb: nlk->cb.skb);
773 WRITE_ONCE(nlk->cb_running, false);
774 }
775
776 module_put(module: nlk->module);
777
778 if (netlink_is_kernel(sk)) {
779 netlink_table_grab();
780 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
781 if (--nl_table[sk->sk_protocol].registered == 0) {
782 struct listeners *old;
783
784 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
785 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
786 kfree_rcu(old, rcu);
787 nl_table[sk->sk_protocol].module = NULL;
788 nl_table[sk->sk_protocol].bind = NULL;
789 nl_table[sk->sk_protocol].unbind = NULL;
790 nl_table[sk->sk_protocol].flags = 0;
791 nl_table[sk->sk_protocol].registered = 0;
792 }
793 netlink_table_ungrab();
794 }
795
796 sock_prot_inuse_add(net: sock_net(sk), prot: &netlink_proto, val: -1);
797
798 call_rcu(head: &nlk->rcu, func: deferred_put_nlk_sk);
799 return 0;
800}
801
802static int netlink_autobind(struct socket *sock)
803{
804 struct sock *sk = sock->sk;
805 struct net *net = sock_net(sk);
806 struct netlink_table *table = &nl_table[sk->sk_protocol];
807 s32 portid = task_tgid_vnr(current);
808 int err;
809 s32 rover = -4096;
810 bool ok;
811
812retry:
813 cond_resched();
814 rcu_read_lock();
815 ok = !__netlink_lookup(table, portid, net);
816 rcu_read_unlock();
817 if (!ok) {
818 /* Bind collision, search negative portid values. */
819 if (rover == -4096)
820 /* rover will be in range [S32_MIN, -4097] */
821 rover = S32_MIN + get_random_u32_below(ceil: -4096 - S32_MIN);
822 else if (rover >= -4096)
823 rover = -4097;
824 portid = rover--;
825 goto retry;
826 }
827
828 err = netlink_insert(sk, portid);
829 if (err == -EADDRINUSE)
830 goto retry;
831
832 /* If 2 threads race to autobind, that is fine. */
833 if (err == -EBUSY)
834 err = 0;
835
836 return err;
837}
838
839/**
840 * __netlink_ns_capable - General netlink message capability test
841 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
842 * @user_ns: The user namespace of the capability to use
843 * @cap: The capability to use
844 *
845 * Test to see if the opener of the socket we received the message
846 * from had when the netlink socket was created and the sender of the
847 * message has the capability @cap in the user namespace @user_ns.
848 */
849bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
850 struct user_namespace *user_ns, int cap)
851{
852 return ((nsp->flags & NETLINK_SKB_DST) ||
853 file_ns_capable(file: nsp->sk->sk_socket->file, ns: user_ns, cap)) &&
854 ns_capable(ns: user_ns, cap);
855}
856EXPORT_SYMBOL(__netlink_ns_capable);
857
858/**
859 * netlink_ns_capable - General netlink message capability test
860 * @skb: socket buffer holding a netlink command from userspace
861 * @user_ns: The user namespace of the capability to use
862 * @cap: The capability to use
863 *
864 * Test to see if the opener of the socket we received the message
865 * from had when the netlink socket was created and the sender of the
866 * message has the capability @cap in the user namespace @user_ns.
867 */
868bool netlink_ns_capable(const struct sk_buff *skb,
869 struct user_namespace *user_ns, int cap)
870{
871 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
872}
873EXPORT_SYMBOL(netlink_ns_capable);
874
875/**
876 * netlink_capable - Netlink global message capability test
877 * @skb: socket buffer holding a netlink command from userspace
878 * @cap: The capability to use
879 *
880 * Test to see if the opener of the socket we received the message
881 * from had when the netlink socket was created and the sender of the
882 * message has the capability @cap in all user namespaces.
883 */
884bool netlink_capable(const struct sk_buff *skb, int cap)
885{
886 return netlink_ns_capable(skb, &init_user_ns, cap);
887}
888EXPORT_SYMBOL(netlink_capable);
889
890/**
891 * netlink_net_capable - Netlink network namespace message capability test
892 * @skb: socket buffer holding a netlink command from userspace
893 * @cap: The capability to use
894 *
895 * Test to see if the opener of the socket we received the message
896 * from had when the netlink socket was created and the sender of the
897 * message has the capability @cap over the network namespace of
898 * the socket we received the message from.
899 */
900bool netlink_net_capable(const struct sk_buff *skb, int cap)
901{
902 return netlink_ns_capable(skb, sock_net(sk: skb->sk)->user_ns, cap);
903}
904EXPORT_SYMBOL(netlink_net_capable);
905
906static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
907{
908 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
909 ns_capable(ns: sock_net(sk: sock->sk)->user_ns, CAP_NET_ADMIN);
910}
911
912static void
913netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
914{
915 struct netlink_sock *nlk = nlk_sk(sk);
916
917 if (nlk->subscriptions && !subscriptions)
918 __sk_del_bind_node(sk);
919 else if (!nlk->subscriptions && subscriptions)
920 sk_add_bind_node(sk, list: &nl_table[sk->sk_protocol].mc_list);
921 nlk->subscriptions = subscriptions;
922}
923
924static int netlink_realloc_groups(struct sock *sk)
925{
926 struct netlink_sock *nlk = nlk_sk(sk);
927 unsigned int groups;
928 unsigned long *new_groups;
929 int err = 0;
930
931 netlink_table_grab();
932
933 groups = nl_table[sk->sk_protocol].groups;
934 if (!nl_table[sk->sk_protocol].registered) {
935 err = -ENOENT;
936 goto out_unlock;
937 }
938
939 if (nlk->ngroups >= groups)
940 goto out_unlock;
941
942 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
943 if (new_groups == NULL) {
944 err = -ENOMEM;
945 goto out_unlock;
946 }
947 memset(s: (char *)new_groups + NLGRPSZ(nlk->ngroups), c: 0,
948 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
949
950 nlk->groups = new_groups;
951 nlk->ngroups = groups;
952 out_unlock:
953 netlink_table_ungrab();
954 return err;
955}
956
957static void netlink_undo_bind(int group, long unsigned int groups,
958 struct sock *sk)
959{
960 struct netlink_sock *nlk = nlk_sk(sk);
961 int undo;
962
963 if (!nlk->netlink_unbind)
964 return;
965
966 for (undo = 0; undo < group; undo++)
967 if (test_bit(undo, &groups))
968 nlk->netlink_unbind(sock_net(sk), undo + 1);
969}
970
971static int netlink_bind(struct socket *sock, struct sockaddr *addr,
972 int addr_len)
973{
974 struct sock *sk = sock->sk;
975 struct net *net = sock_net(sk);
976 struct netlink_sock *nlk = nlk_sk(sk);
977 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
978 int err = 0;
979 unsigned long groups;
980 bool bound;
981
982 if (addr_len < sizeof(struct sockaddr_nl))
983 return -EINVAL;
984
985 if (nladdr->nl_family != AF_NETLINK)
986 return -EINVAL;
987 groups = nladdr->nl_groups;
988
989 /* Only superuser is allowed to listen multicasts */
990 if (groups) {
991 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
992 return -EPERM;
993 err = netlink_realloc_groups(sk);
994 if (err)
995 return err;
996 }
997
998 if (nlk->ngroups < BITS_PER_LONG)
999 groups &= (1UL << nlk->ngroups) - 1;
1000
1001 /* Paired with WRITE_ONCE() in netlink_insert() */
1002 bound = READ_ONCE(nlk->bound);
1003 if (bound) {
1004 /* Ensure nlk->portid is up-to-date. */
1005 smp_rmb();
1006
1007 if (nladdr->nl_pid != nlk->portid)
1008 return -EINVAL;
1009 }
1010
1011 if (nlk->netlink_bind && groups) {
1012 int group;
1013
1014 /* nl_groups is a u32, so cap the maximum groups we can bind */
1015 for (group = 0; group < BITS_PER_TYPE(u32); group++) {
1016 if (!test_bit(group, &groups))
1017 continue;
1018 err = nlk->netlink_bind(net, group + 1);
1019 if (!err)
1020 continue;
1021 netlink_undo_bind(group, groups, sk);
1022 return err;
1023 }
1024 }
1025
1026 /* No need for barriers here as we return to user-space without
1027 * using any of the bound attributes.
1028 */
1029 netlink_lock_table();
1030 if (!bound) {
1031 err = nladdr->nl_pid ?
1032 netlink_insert(sk, portid: nladdr->nl_pid) :
1033 netlink_autobind(sock);
1034 if (err) {
1035 netlink_undo_bind(BITS_PER_TYPE(u32), groups, sk);
1036 goto unlock;
1037 }
1038 }
1039
1040 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1041 goto unlock;
1042 netlink_unlock_table();
1043
1044 netlink_table_grab();
1045 netlink_update_subscriptions(sk, subscriptions: nlk->subscriptions +
1046 hweight32(groups) -
1047 hweight32(nlk->groups[0]));
1048 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1049 netlink_update_listeners(sk);
1050 netlink_table_ungrab();
1051
1052 return 0;
1053
1054unlock:
1055 netlink_unlock_table();
1056 return err;
1057}
1058
1059static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1060 int alen, int flags)
1061{
1062 int err = 0;
1063 struct sock *sk = sock->sk;
1064 struct netlink_sock *nlk = nlk_sk(sk);
1065 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1066
1067 if (alen < sizeof(addr->sa_family))
1068 return -EINVAL;
1069
1070 if (addr->sa_family == AF_UNSPEC) {
1071 /* paired with READ_ONCE() in netlink_getsockbyportid() */
1072 WRITE_ONCE(sk->sk_state, NETLINK_UNCONNECTED);
1073 /* dst_portid and dst_group can be read locklessly */
1074 WRITE_ONCE(nlk->dst_portid, 0);
1075 WRITE_ONCE(nlk->dst_group, 0);
1076 return 0;
1077 }
1078 if (addr->sa_family != AF_NETLINK)
1079 return -EINVAL;
1080
1081 if (alen < sizeof(struct sockaddr_nl))
1082 return -EINVAL;
1083
1084 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1085 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1086 return -EPERM;
1087
1088 /* No need for barriers here as we return to user-space without
1089 * using any of the bound attributes.
1090 * Paired with WRITE_ONCE() in netlink_insert().
1091 */
1092 if (!READ_ONCE(nlk->bound))
1093 err = netlink_autobind(sock);
1094
1095 if (err == 0) {
1096 /* paired with READ_ONCE() in netlink_getsockbyportid() */
1097 WRITE_ONCE(sk->sk_state, NETLINK_CONNECTED);
1098 /* dst_portid and dst_group can be read locklessly */
1099 WRITE_ONCE(nlk->dst_portid, nladdr->nl_pid);
1100 WRITE_ONCE(nlk->dst_group, ffs(nladdr->nl_groups));
1101 }
1102
1103 return err;
1104}
1105
1106static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1107 int peer)
1108{
1109 struct sock *sk = sock->sk;
1110 struct netlink_sock *nlk = nlk_sk(sk);
1111 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1112
1113 nladdr->nl_family = AF_NETLINK;
1114 nladdr->nl_pad = 0;
1115
1116 if (peer) {
1117 /* Paired with WRITE_ONCE() in netlink_connect() */
1118 nladdr->nl_pid = READ_ONCE(nlk->dst_portid);
1119 nladdr->nl_groups = netlink_group_mask(READ_ONCE(nlk->dst_group));
1120 } else {
1121 /* Paired with WRITE_ONCE() in netlink_insert() */
1122 nladdr->nl_pid = READ_ONCE(nlk->portid);
1123 netlink_lock_table();
1124 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1125 netlink_unlock_table();
1126 }
1127 return sizeof(*nladdr);
1128}
1129
1130static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1131 unsigned long arg)
1132{
1133 /* try to hand this ioctl down to the NIC drivers.
1134 */
1135 return -ENOIOCTLCMD;
1136}
1137
1138static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1139{
1140 struct sock *sock;
1141 struct netlink_sock *nlk;
1142
1143 sock = netlink_lookup(net: sock_net(sk: ssk), protocol: ssk->sk_protocol, portid);
1144 if (!sock)
1145 return ERR_PTR(error: -ECONNREFUSED);
1146
1147 /* Don't bother queuing skb if kernel socket has no input function */
1148 nlk = nlk_sk(sk: sock);
1149 /* dst_portid and sk_state can be changed in netlink_connect() */
1150 if (READ_ONCE(sock->sk_state) == NETLINK_CONNECTED &&
1151 READ_ONCE(nlk->dst_portid) != nlk_sk(sk: ssk)->portid) {
1152 sock_put(sk: sock);
1153 return ERR_PTR(error: -ECONNREFUSED);
1154 }
1155 return sock;
1156}
1157
1158struct sock *netlink_getsockbyfd(int fd)
1159{
1160 CLASS(fd, f)(fd);
1161 struct inode *inode;
1162 struct sock *sock;
1163
1164 if (fd_empty(f))
1165 return ERR_PTR(error: -EBADF);
1166
1167 inode = file_inode(fd_file(f));
1168 if (!S_ISSOCK(inode->i_mode))
1169 return ERR_PTR(error: -ENOTSOCK);
1170
1171 sock = SOCKET_I(inode)->sk;
1172 if (sock->sk_family != AF_NETLINK)
1173 return ERR_PTR(error: -EINVAL);
1174
1175 sock_hold(sk: sock);
1176 return sock;
1177}
1178
1179struct sk_buff *netlink_alloc_large_skb(unsigned int size, int broadcast)
1180{
1181 size_t head_size = SKB_HEAD_ALIGN(size);
1182 struct sk_buff *skb;
1183 void *data;
1184
1185 if (head_size <= PAGE_SIZE || broadcast)
1186 return alloc_skb(size, GFP_KERNEL);
1187
1188 data = kvmalloc(head_size, GFP_KERNEL);
1189 if (!data)
1190 return NULL;
1191
1192 skb = __build_skb(data, frag_size: head_size);
1193 if (!skb)
1194 kvfree(addr: data);
1195 else if (is_vmalloc_addr(x: data))
1196 skb->destructor = netlink_skb_destructor;
1197
1198 return skb;
1199}
1200
1201/*
1202 * Attach a skb to a netlink socket.
1203 * The caller must hold a reference to the destination socket. On error, the
1204 * reference is dropped. The skb is not send to the destination, just all
1205 * all error checks are performed and memory in the queue is reserved.
1206 * Return values:
1207 * < 0: error. skb freed, reference to sock dropped.
1208 * 0: continue
1209 * 1: repeat lookup - reference dropped while waiting for socket memory.
1210 */
1211int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1212 long *timeo, struct sock *ssk)
1213{
1214 DECLARE_WAITQUEUE(wait, current);
1215 struct netlink_sock *nlk;
1216 unsigned int rmem;
1217
1218 nlk = nlk_sk(sk);
1219 rmem = atomic_add_return(i: skb->truesize, v: &sk->sk_rmem_alloc);
1220
1221 if ((rmem == skb->truesize || rmem <= READ_ONCE(sk->sk_rcvbuf)) &&
1222 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1223 netlink_skb_set_owner_r(skb, sk);
1224 return 0;
1225 }
1226
1227 atomic_sub(i: skb->truesize, v: &sk->sk_rmem_alloc);
1228
1229 if (!*timeo) {
1230 if (!ssk || netlink_is_kernel(sk: ssk))
1231 netlink_overrun(sk);
1232 sock_put(sk);
1233 kfree_skb(skb);
1234 return -EAGAIN;
1235 }
1236
1237 __set_current_state(TASK_INTERRUPTIBLE);
1238 add_wait_queue(wq_head: &nlk->wait, wq_entry: &wait);
1239 rmem = atomic_read(v: &sk->sk_rmem_alloc);
1240
1241 if (((rmem && rmem + skb->truesize > READ_ONCE(sk->sk_rcvbuf)) ||
1242 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1243 !sock_flag(sk, flag: SOCK_DEAD))
1244 *timeo = schedule_timeout(timeout: *timeo);
1245
1246 __set_current_state(TASK_RUNNING);
1247 remove_wait_queue(wq_head: &nlk->wait, wq_entry: &wait);
1248 sock_put(sk);
1249
1250 if (signal_pending(current)) {
1251 kfree_skb(skb);
1252 return sock_intr_errno(timeo: *timeo);
1253 }
1254
1255 return 1;
1256}
1257
1258static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1259{
1260 int len = skb->len;
1261
1262 netlink_deliver_tap(net: sock_net(sk), skb);
1263
1264 skb_queue_tail(list: &sk->sk_receive_queue, newsk: skb);
1265 sk->sk_data_ready(sk);
1266 return len;
1267}
1268
1269int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1270{
1271 int len = __netlink_sendskb(sk, skb);
1272
1273 sock_put(sk);
1274 return len;
1275}
1276
1277void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1278{
1279 kfree_skb(skb);
1280 sock_put(sk);
1281}
1282
1283static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1284{
1285 int delta;
1286
1287 skb_assert_len(skb);
1288 WARN_ON(skb->sk != NULL);
1289 delta = skb->end - skb->tail;
1290 if (is_vmalloc_addr(x: skb->head) || delta * 2 < skb->truesize)
1291 return skb;
1292
1293 if (skb_shared(skb)) {
1294 struct sk_buff *nskb = skb_clone(skb, priority: allocation);
1295 if (!nskb)
1296 return skb;
1297 consume_skb(skb);
1298 skb = nskb;
1299 }
1300
1301 pskb_expand_head(skb, nhead: 0, ntail: -delta,
1302 gfp_mask: (allocation & ~__GFP_DIRECT_RECLAIM) |
1303 __GFP_NOWARN | __GFP_NORETRY);
1304 return skb;
1305}
1306
1307static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1308 struct sock *ssk)
1309{
1310 int ret;
1311 struct netlink_sock *nlk = nlk_sk(sk);
1312
1313 ret = -ECONNREFUSED;
1314 if (nlk->netlink_rcv != NULL) {
1315 ret = skb->len;
1316 atomic_add(i: skb->truesize, v: &sk->sk_rmem_alloc);
1317 netlink_skb_set_owner_r(skb, sk);
1318 NETLINK_CB(skb).sk = ssk;
1319 netlink_deliver_tap_kernel(dst: sk, src: ssk, skb);
1320 nlk->netlink_rcv(skb);
1321 consume_skb(skb);
1322 } else {
1323 kfree_skb(skb);
1324 }
1325 sock_put(sk);
1326 return ret;
1327}
1328
1329int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1330 u32 portid, int nonblock)
1331{
1332 struct sock *sk;
1333 int err;
1334 long timeo;
1335
1336 skb = netlink_trim(skb, allocation: gfp_any());
1337
1338 timeo = sock_sndtimeo(sk: ssk, noblock: nonblock);
1339retry:
1340 sk = netlink_getsockbyportid(ssk, portid);
1341 if (IS_ERR(ptr: sk)) {
1342 kfree_skb(skb);
1343 return PTR_ERR(ptr: sk);
1344 }
1345 if (netlink_is_kernel(sk))
1346 return netlink_unicast_kernel(sk, skb, ssk);
1347
1348 if (sk_filter(sk, skb)) {
1349 err = skb->len;
1350 kfree_skb(skb);
1351 sock_put(sk);
1352 return err;
1353 }
1354
1355 err = netlink_attachskb(sk, skb, timeo: &timeo, ssk);
1356 if (err == 1)
1357 goto retry;
1358 if (err)
1359 return err;
1360
1361 return netlink_sendskb(sk, skb);
1362}
1363EXPORT_SYMBOL(netlink_unicast);
1364
1365int netlink_has_listeners(struct sock *sk, unsigned int group)
1366{
1367 int res = 0;
1368 struct listeners *listeners;
1369
1370 BUG_ON(!netlink_is_kernel(sk));
1371
1372 rcu_read_lock();
1373 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1374
1375 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1376 res = test_bit(group - 1, listeners->masks);
1377
1378 rcu_read_unlock();
1379
1380 return res;
1381}
1382EXPORT_SYMBOL_GPL(netlink_has_listeners);
1383
1384bool netlink_strict_get_check(struct sk_buff *skb)
1385{
1386 return nlk_test_bit(STRICT_CHK, NETLINK_CB(skb).sk);
1387}
1388EXPORT_SYMBOL_GPL(netlink_strict_get_check);
1389
1390static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1391{
1392 struct netlink_sock *nlk = nlk_sk(sk);
1393 unsigned int rmem, rcvbuf;
1394
1395 rmem = atomic_add_return(i: skb->truesize, v: &sk->sk_rmem_alloc);
1396 rcvbuf = READ_ONCE(sk->sk_rcvbuf);
1397
1398 if ((rmem == skb->truesize || rmem <= rcvbuf) &&
1399 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1400 netlink_skb_set_owner_r(skb, sk);
1401 __netlink_sendskb(sk, skb);
1402 return rmem > (rcvbuf >> 1);
1403 }
1404
1405 atomic_sub(i: skb->truesize, v: &sk->sk_rmem_alloc);
1406 return -1;
1407}
1408
1409struct netlink_broadcast_data {
1410 struct sock *exclude_sk;
1411 struct net *net;
1412 u32 portid;
1413 u32 group;
1414 int failure;
1415 int delivery_failure;
1416 int congested;
1417 int delivered;
1418 gfp_t allocation;
1419 struct sk_buff *skb, *skb2;
1420 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1421 void *tx_data;
1422};
1423
1424static void do_one_broadcast(struct sock *sk,
1425 struct netlink_broadcast_data *p)
1426{
1427 struct netlink_sock *nlk = nlk_sk(sk);
1428 int val;
1429
1430 if (p->exclude_sk == sk)
1431 return;
1432
1433 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1434 !test_bit(p->group - 1, nlk->groups))
1435 return;
1436
1437 if (!net_eq(net1: sock_net(sk), net2: p->net)) {
1438 if (!nlk_test_bit(LISTEN_ALL_NSID, sk))
1439 return;
1440
1441 if (!peernet_has_id(net: sock_net(sk), peer: p->net))
1442 return;
1443
1444 if (!file_ns_capable(file: sk->sk_socket->file, ns: p->net->user_ns,
1445 CAP_NET_BROADCAST))
1446 return;
1447 }
1448
1449 if (p->failure) {
1450 netlink_overrun(sk);
1451 return;
1452 }
1453
1454 sock_hold(sk);
1455 if (p->skb2 == NULL) {
1456 if (skb_shared(skb: p->skb)) {
1457 p->skb2 = skb_clone(skb: p->skb, priority: p->allocation);
1458 } else {
1459 p->skb2 = skb_get(skb: p->skb);
1460 /*
1461 * skb ownership may have been set when
1462 * delivered to a previous socket.
1463 */
1464 skb_orphan(skb: p->skb2);
1465 }
1466 }
1467 if (p->skb2 == NULL) {
1468 netlink_overrun(sk);
1469 /* Clone failed. Notify ALL listeners. */
1470 p->failure = 1;
1471 if (nlk_test_bit(BROADCAST_SEND_ERROR, sk))
1472 p->delivery_failure = 1;
1473 goto out;
1474 }
1475
1476 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1477 kfree_skb(skb: p->skb2);
1478 p->skb2 = NULL;
1479 goto out;
1480 }
1481
1482 if (sk_filter(sk, skb: p->skb2)) {
1483 kfree_skb(skb: p->skb2);
1484 p->skb2 = NULL;
1485 goto out;
1486 }
1487 NETLINK_CB(p->skb2).nsid = peernet2id(net: sock_net(sk), peer: p->net);
1488 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
1489 NETLINK_CB(p->skb2).nsid_is_set = true;
1490 val = netlink_broadcast_deliver(sk, skb: p->skb2);
1491 if (val < 0) {
1492 netlink_overrun(sk);
1493 if (nlk_test_bit(BROADCAST_SEND_ERROR, sk))
1494 p->delivery_failure = 1;
1495 } else {
1496 p->congested |= val;
1497 p->delivered = 1;
1498 p->skb2 = NULL;
1499 }
1500out:
1501 sock_put(sk);
1502}
1503
1504int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
1505 u32 portid,
1506 u32 group, gfp_t allocation,
1507 netlink_filter_fn filter,
1508 void *filter_data)
1509{
1510 struct net *net = sock_net(sk: ssk);
1511 struct netlink_broadcast_data info;
1512 struct sock *sk;
1513
1514 skb = netlink_trim(skb, allocation);
1515
1516 info.exclude_sk = ssk;
1517 info.net = net;
1518 info.portid = portid;
1519 info.group = group;
1520 info.failure = 0;
1521 info.delivery_failure = 0;
1522 info.congested = 0;
1523 info.delivered = 0;
1524 info.allocation = allocation;
1525 info.skb = skb;
1526 info.skb2 = NULL;
1527 info.tx_filter = filter;
1528 info.tx_data = filter_data;
1529
1530 /* While we sleep in clone, do not allow to change socket list */
1531
1532 netlink_lock_table();
1533
1534 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1535 do_one_broadcast(sk, p: &info);
1536
1537 consume_skb(skb);
1538
1539 netlink_unlock_table();
1540
1541 if (info.delivery_failure) {
1542 kfree_skb(skb: info.skb2);
1543 return -ENOBUFS;
1544 }
1545 consume_skb(skb: info.skb2);
1546
1547 if (info.delivered) {
1548 if (info.congested && gfpflags_allow_blocking(gfp_flags: allocation))
1549 yield();
1550 return 0;
1551 }
1552 return -ESRCH;
1553}
1554EXPORT_SYMBOL(netlink_broadcast_filtered);
1555
1556int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1557 u32 group, gfp_t allocation)
1558{
1559 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1560 NULL, NULL);
1561}
1562EXPORT_SYMBOL(netlink_broadcast);
1563
1564struct netlink_set_err_data {
1565 struct sock *exclude_sk;
1566 u32 portid;
1567 u32 group;
1568 int code;
1569};
1570
1571static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1572{
1573 struct netlink_sock *nlk = nlk_sk(sk);
1574 int ret = 0;
1575
1576 if (sk == p->exclude_sk)
1577 goto out;
1578
1579 if (!net_eq(net1: sock_net(sk), net2: sock_net(sk: p->exclude_sk)))
1580 goto out;
1581
1582 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1583 !test_bit(p->group - 1, nlk->groups))
1584 goto out;
1585
1586 if (p->code == ENOBUFS && nlk_test_bit(RECV_NO_ENOBUFS, sk)) {
1587 ret = 1;
1588 goto out;
1589 }
1590
1591 WRITE_ONCE(sk->sk_err, p->code);
1592 sk_error_report(sk);
1593out:
1594 return ret;
1595}
1596
1597/**
1598 * netlink_set_err - report error to broadcast listeners
1599 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1600 * @portid: the PORTID of a process that we want to skip (if any)
1601 * @group: the broadcast group that will notice the error
1602 * @code: error code, must be negative (as usual in kernelspace)
1603 *
1604 * This function returns the number of broadcast listeners that have set the
1605 * NETLINK_NO_ENOBUFS socket option.
1606 */
1607int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1608{
1609 struct netlink_set_err_data info;
1610 unsigned long flags;
1611 struct sock *sk;
1612 int ret = 0;
1613
1614 info.exclude_sk = ssk;
1615 info.portid = portid;
1616 info.group = group;
1617 /* sk->sk_err wants a positive error value */
1618 info.code = -code;
1619
1620 read_lock_irqsave(&nl_table_lock, flags);
1621
1622 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1623 ret += do_one_set_err(sk, p: &info);
1624
1625 read_unlock_irqrestore(&nl_table_lock, flags);
1626 return ret;
1627}
1628EXPORT_SYMBOL(netlink_set_err);
1629
1630/* must be called with netlink table grabbed */
1631static void netlink_update_socket_mc(struct netlink_sock *nlk,
1632 unsigned int group,
1633 int is_new)
1634{
1635 int old, new = !!is_new, subscriptions;
1636
1637 old = test_bit(group - 1, nlk->groups);
1638 subscriptions = nlk->subscriptions - old + new;
1639 __assign_bit(group - 1, nlk->groups, new);
1640 netlink_update_subscriptions(sk: &nlk->sk, subscriptions);
1641 netlink_update_listeners(sk: &nlk->sk);
1642}
1643
1644static int netlink_setsockopt(struct socket *sock, int level, int optname,
1645 sockptr_t optval, unsigned int optlen)
1646{
1647 struct sock *sk = sock->sk;
1648 struct netlink_sock *nlk = nlk_sk(sk);
1649 unsigned int val = 0;
1650 int nr = -1;
1651
1652 if (level != SOL_NETLINK)
1653 return -ENOPROTOOPT;
1654
1655 if (optlen >= sizeof(int) &&
1656 copy_from_sockptr(dst: &val, src: optval, size: sizeof(val)))
1657 return -EFAULT;
1658
1659 switch (optname) {
1660 case NETLINK_PKTINFO:
1661 nr = NETLINK_F_RECV_PKTINFO;
1662 break;
1663 case NETLINK_ADD_MEMBERSHIP:
1664 case NETLINK_DROP_MEMBERSHIP: {
1665 int err;
1666
1667 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1668 return -EPERM;
1669 err = netlink_realloc_groups(sk);
1670 if (err)
1671 return err;
1672 if (!val || val - 1 >= nlk->ngroups)
1673 return -EINVAL;
1674 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1675 err = nlk->netlink_bind(sock_net(sk), val);
1676 if (err)
1677 return err;
1678 }
1679 netlink_table_grab();
1680 netlink_update_socket_mc(nlk, group: val,
1681 is_new: optname == NETLINK_ADD_MEMBERSHIP);
1682 netlink_table_ungrab();
1683 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1684 nlk->netlink_unbind(sock_net(sk), val);
1685
1686 break;
1687 }
1688 case NETLINK_BROADCAST_ERROR:
1689 nr = NETLINK_F_BROADCAST_SEND_ERROR;
1690 break;
1691 case NETLINK_NO_ENOBUFS:
1692 assign_bit(NETLINK_F_RECV_NO_ENOBUFS, &nlk->flags, val);
1693 if (val) {
1694 clear_bit(NETLINK_S_CONGESTED, addr: &nlk->state);
1695 wake_up_interruptible(&nlk->wait);
1696 }
1697 break;
1698 case NETLINK_LISTEN_ALL_NSID:
1699 if (!ns_capable(ns: sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1700 return -EPERM;
1701 nr = NETLINK_F_LISTEN_ALL_NSID;
1702 break;
1703 case NETLINK_CAP_ACK:
1704 nr = NETLINK_F_CAP_ACK;
1705 break;
1706 case NETLINK_EXT_ACK:
1707 nr = NETLINK_F_EXT_ACK;
1708 break;
1709 case NETLINK_GET_STRICT_CHK:
1710 nr = NETLINK_F_STRICT_CHK;
1711 break;
1712 default:
1713 return -ENOPROTOOPT;
1714 }
1715 if (nr >= 0)
1716 assign_bit(nr, &nlk->flags, val);
1717 return 0;
1718}
1719
1720static int netlink_getsockopt(struct socket *sock, int level, int optname,
1721 char __user *optval, int __user *optlen)
1722{
1723 struct sock *sk = sock->sk;
1724 struct netlink_sock *nlk = nlk_sk(sk);
1725 unsigned int flag;
1726 int len, val;
1727
1728 if (level != SOL_NETLINK)
1729 return -ENOPROTOOPT;
1730
1731 if (get_user(len, optlen))
1732 return -EFAULT;
1733 if (len < 0)
1734 return -EINVAL;
1735
1736 switch (optname) {
1737 case NETLINK_PKTINFO:
1738 flag = NETLINK_F_RECV_PKTINFO;
1739 break;
1740 case NETLINK_BROADCAST_ERROR:
1741 flag = NETLINK_F_BROADCAST_SEND_ERROR;
1742 break;
1743 case NETLINK_NO_ENOBUFS:
1744 flag = NETLINK_F_RECV_NO_ENOBUFS;
1745 break;
1746 case NETLINK_LIST_MEMBERSHIPS: {
1747 int pos, idx, shift, err = 0;
1748
1749 netlink_lock_table();
1750 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1751 if (len - pos < sizeof(u32))
1752 break;
1753
1754 idx = pos / sizeof(unsigned long);
1755 shift = (pos % sizeof(unsigned long)) * 8;
1756 if (put_user((u32)(nlk->groups[idx] >> shift),
1757 (u32 __user *)(optval + pos))) {
1758 err = -EFAULT;
1759 break;
1760 }
1761 }
1762 if (put_user(ALIGN(BITS_TO_BYTES(nlk->ngroups), sizeof(u32)), optlen))
1763 err = -EFAULT;
1764 netlink_unlock_table();
1765 return err;
1766 }
1767 case NETLINK_LISTEN_ALL_NSID:
1768 flag = NETLINK_F_LISTEN_ALL_NSID;
1769 break;
1770 case NETLINK_CAP_ACK:
1771 flag = NETLINK_F_CAP_ACK;
1772 break;
1773 case NETLINK_EXT_ACK:
1774 flag = NETLINK_F_EXT_ACK;
1775 break;
1776 case NETLINK_GET_STRICT_CHK:
1777 flag = NETLINK_F_STRICT_CHK;
1778 break;
1779 default:
1780 return -ENOPROTOOPT;
1781 }
1782
1783 if (len < sizeof(int))
1784 return -EINVAL;
1785
1786 len = sizeof(int);
1787 val = test_bit(flag, &nlk->flags);
1788
1789 if (put_user(len, optlen) ||
1790 copy_to_user(to: optval, from: &val, n: len))
1791 return -EFAULT;
1792
1793 return 0;
1794}
1795
1796static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1797{
1798 struct nl_pktinfo info;
1799
1800 info.group = NETLINK_CB(skb).dst_group;
1801 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, len: sizeof(info), data: &info);
1802}
1803
1804static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1805 struct sk_buff *skb)
1806{
1807 if (!NETLINK_CB(skb).nsid_is_set)
1808 return;
1809
1810 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, len: sizeof(int),
1811 data: &NETLINK_CB(skb).nsid);
1812}
1813
1814static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1815{
1816 struct sock *sk = sock->sk;
1817 struct netlink_sock *nlk = nlk_sk(sk);
1818 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1819 u32 dst_portid;
1820 u32 dst_group;
1821 struct sk_buff *skb;
1822 int err;
1823 struct scm_cookie scm;
1824 u32 netlink_skb_flags = 0;
1825
1826 if (msg->msg_flags & MSG_OOB)
1827 return -EOPNOTSUPP;
1828
1829 if (len == 0) {
1830 pr_warn_once("Zero length message leads to an empty skb\n");
1831 return -ENODATA;
1832 }
1833
1834 err = scm_send(sock, msg, scm: &scm, forcecreds: true);
1835 if (err < 0)
1836 return err;
1837
1838 if (msg->msg_namelen) {
1839 err = -EINVAL;
1840 if (msg->msg_namelen < sizeof(struct sockaddr_nl))
1841 goto out;
1842 if (addr->nl_family != AF_NETLINK)
1843 goto out;
1844 dst_portid = addr->nl_pid;
1845 dst_group = ffs(addr->nl_groups);
1846 err = -EPERM;
1847 if ((dst_group || dst_portid) &&
1848 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1849 goto out;
1850 netlink_skb_flags |= NETLINK_SKB_DST;
1851 } else {
1852 /* Paired with WRITE_ONCE() in netlink_connect() */
1853 dst_portid = READ_ONCE(nlk->dst_portid);
1854 dst_group = READ_ONCE(nlk->dst_group);
1855 }
1856
1857 /* Paired with WRITE_ONCE() in netlink_insert() */
1858 if (!READ_ONCE(nlk->bound)) {
1859 err = netlink_autobind(sock);
1860 if (err)
1861 goto out;
1862 } else {
1863 /* Ensure nlk is hashed and visible. */
1864 smp_rmb();
1865 }
1866
1867 err = -EMSGSIZE;
1868 if (len > sk->sk_sndbuf - 32)
1869 goto out;
1870 err = -ENOBUFS;
1871 skb = netlink_alloc_large_skb(size: len, broadcast: dst_group);
1872 if (skb == NULL)
1873 goto out;
1874
1875 NETLINK_CB(skb).portid = nlk->portid;
1876 NETLINK_CB(skb).dst_group = dst_group;
1877 NETLINK_CB(skb).creds = scm.creds;
1878 NETLINK_CB(skb).flags = netlink_skb_flags;
1879
1880 err = -EFAULT;
1881 if (memcpy_from_msg(data: skb_put(skb, len), msg, len)) {
1882 kfree_skb(skb);
1883 goto out;
1884 }
1885
1886 err = security_netlink_send(sk, skb);
1887 if (err) {
1888 kfree_skb(skb);
1889 goto out;
1890 }
1891
1892 if (dst_group) {
1893 refcount_inc(r: &skb->users);
1894 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1895 }
1896 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags & MSG_DONTWAIT);
1897
1898out:
1899 scm_destroy(scm: &scm);
1900 return err;
1901}
1902
1903static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1904 int flags)
1905{
1906 struct scm_cookie scm;
1907 struct sock *sk = sock->sk;
1908 struct netlink_sock *nlk = nlk_sk(sk);
1909 size_t copied, max_recvmsg_len;
1910 struct sk_buff *skb, *data_skb;
1911 int err, ret;
1912
1913 if (flags & MSG_OOB)
1914 return -EOPNOTSUPP;
1915
1916 copied = 0;
1917
1918 skb = skb_recv_datagram(sk, flags, err: &err);
1919 if (skb == NULL)
1920 goto out;
1921
1922 data_skb = skb;
1923
1924#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1925 if (unlikely(skb_shinfo(skb)->frag_list)) {
1926 /*
1927 * If this skb has a frag_list, then here that means that we
1928 * will have to use the frag_list skb's data for compat tasks
1929 * and the regular skb's data for normal (non-compat) tasks.
1930 *
1931 * If we need to send the compat skb, assign it to the
1932 * 'data_skb' variable so that it will be used below for data
1933 * copying. We keep 'skb' for everything else, including
1934 * freeing both later.
1935 */
1936 if (flags & MSG_CMSG_COMPAT)
1937 data_skb = skb_shinfo(skb)->frag_list;
1938 }
1939#endif
1940
1941 /* Record the max length of recvmsg() calls for future allocations */
1942 max_recvmsg_len = max(READ_ONCE(nlk->max_recvmsg_len), len);
1943 max_recvmsg_len = min_t(size_t, max_recvmsg_len,
1944 SKB_WITH_OVERHEAD(32768));
1945 WRITE_ONCE(nlk->max_recvmsg_len, max_recvmsg_len);
1946
1947 copied = data_skb->len;
1948 if (len < copied) {
1949 msg->msg_flags |= MSG_TRUNC;
1950 copied = len;
1951 }
1952
1953 err = skb_copy_datagram_msg(from: data_skb, offset: 0, msg, size: copied);
1954
1955 if (msg->msg_name) {
1956 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1957 addr->nl_family = AF_NETLINK;
1958 addr->nl_pad = 0;
1959 addr->nl_pid = NETLINK_CB(skb).portid;
1960 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1961 msg->msg_namelen = sizeof(*addr);
1962 }
1963
1964 if (nlk_test_bit(RECV_PKTINFO, sk))
1965 netlink_cmsg_recv_pktinfo(msg, skb);
1966 if (nlk_test_bit(LISTEN_ALL_NSID, sk))
1967 netlink_cmsg_listen_all_nsid(sk, msg, skb);
1968
1969 memset(s: &scm, c: 0, n: sizeof(scm));
1970 scm.creds = *NETLINK_CREDS(skb);
1971 if (flags & MSG_TRUNC)
1972 copied = data_skb->len;
1973
1974 skb_free_datagram(sk, skb);
1975
1976 if (READ_ONCE(nlk->cb_running) &&
1977 atomic_read(v: &sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1978 ret = netlink_dump(sk, lock_taken: false);
1979 if (ret) {
1980 WRITE_ONCE(sk->sk_err, -ret);
1981 sk_error_report(sk);
1982 }
1983 }
1984
1985 scm_recv(sock, msg, scm: &scm, flags);
1986out:
1987 netlink_rcv_wake(sk);
1988 return err ? : copied;
1989}
1990
1991static void netlink_data_ready(struct sock *sk)
1992{
1993 BUG();
1994}
1995
1996/*
1997 * We export these functions to other modules. They provide a
1998 * complete set of kernel non-blocking support for message
1999 * queueing.
2000 */
2001
2002struct sock *
2003__netlink_kernel_create(struct net *net, int unit, struct module *module,
2004 struct netlink_kernel_cfg *cfg)
2005{
2006 struct socket *sock;
2007 struct sock *sk;
2008 struct netlink_sock *nlk;
2009 struct listeners *listeners = NULL;
2010 unsigned int groups;
2011
2012 BUG_ON(!nl_table);
2013
2014 if (unit < 0 || unit >= MAX_LINKS)
2015 return NULL;
2016
2017 if (sock_create_lite(PF_NETLINK, type: SOCK_DGRAM, proto: unit, res: &sock))
2018 return NULL;
2019
2020 if (__netlink_create(net, sock, protocol: unit, kern: 1) < 0)
2021 goto out_sock_release_nosk;
2022
2023 sk = sock->sk;
2024
2025 if (!cfg || cfg->groups < 32)
2026 groups = 32;
2027 else
2028 groups = cfg->groups;
2029
2030 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2031 if (!listeners)
2032 goto out_sock_release;
2033
2034 sk->sk_data_ready = netlink_data_ready;
2035 if (cfg && cfg->input)
2036 nlk_sk(sk)->netlink_rcv = cfg->input;
2037
2038 if (netlink_insert(sk, portid: 0))
2039 goto out_sock_release;
2040
2041 nlk = nlk_sk(sk);
2042 set_bit(nr: NETLINK_F_KERNEL_SOCKET, addr: &nlk->flags);
2043
2044 netlink_table_grab();
2045 if (!nl_table[unit].registered) {
2046 nl_table[unit].groups = groups;
2047 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2048 nl_table[unit].module = module;
2049 if (cfg) {
2050 nl_table[unit].bind = cfg->bind;
2051 nl_table[unit].unbind = cfg->unbind;
2052 nl_table[unit].release = cfg->release;
2053 nl_table[unit].flags = cfg->flags;
2054 }
2055 nl_table[unit].registered = 1;
2056 } else {
2057 kfree(objp: listeners);
2058 nl_table[unit].registered++;
2059 }
2060 netlink_table_ungrab();
2061 return sk;
2062
2063out_sock_release:
2064 kfree(objp: listeners);
2065 netlink_kernel_release(sk);
2066 return NULL;
2067
2068out_sock_release_nosk:
2069 sock_release(sock);
2070 return NULL;
2071}
2072EXPORT_SYMBOL(__netlink_kernel_create);
2073
2074void
2075netlink_kernel_release(struct sock *sk)
2076{
2077 if (sk == NULL || sk->sk_socket == NULL)
2078 return;
2079
2080 sock_release(sock: sk->sk_socket);
2081}
2082EXPORT_SYMBOL(netlink_kernel_release);
2083
2084int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2085{
2086 struct listeners *new, *old;
2087 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2088
2089 if (groups < 32)
2090 groups = 32;
2091
2092 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2093 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2094 if (!new)
2095 return -ENOMEM;
2096 old = nl_deref_protected(tbl->listeners);
2097 memcpy(to: new->masks, from: old->masks, NLGRPSZ(tbl->groups));
2098 rcu_assign_pointer(tbl->listeners, new);
2099
2100 kfree_rcu(old, rcu);
2101 }
2102 tbl->groups = groups;
2103
2104 return 0;
2105}
2106
2107/**
2108 * netlink_change_ngroups - change number of multicast groups
2109 *
2110 * This changes the number of multicast groups that are available
2111 * on a certain netlink family. Note that it is not possible to
2112 * change the number of groups to below 32. Also note that it does
2113 * not implicitly call netlink_clear_multicast_users() when the
2114 * number of groups is reduced.
2115 *
2116 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2117 * @groups: The new number of groups.
2118 */
2119int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2120{
2121 int err;
2122
2123 netlink_table_grab();
2124 err = __netlink_change_ngroups(sk, groups);
2125 netlink_table_ungrab();
2126
2127 return err;
2128}
2129
2130void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2131{
2132 struct sock *sk;
2133 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2134 struct hlist_node *tmp;
2135
2136 sk_for_each_bound_safe(sk, tmp, &tbl->mc_list)
2137 netlink_update_socket_mc(nlk: nlk_sk(sk), group, is_new: 0);
2138}
2139
2140struct nlmsghdr *
2141__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2142{
2143 struct nlmsghdr *nlh;
2144 int size = nlmsg_msg_size(payload: len);
2145
2146 nlh = skb_put(skb, NLMSG_ALIGN(size));
2147 nlh->nlmsg_type = type;
2148 nlh->nlmsg_len = size;
2149 nlh->nlmsg_flags = flags;
2150 nlh->nlmsg_pid = portid;
2151 nlh->nlmsg_seq = seq;
2152 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2153 memset(s: nlmsg_data(nlh) + len, c: 0, NLMSG_ALIGN(size) - size);
2154 return nlh;
2155}
2156EXPORT_SYMBOL(__nlmsg_put);
2157
2158static size_t
2159netlink_ack_tlv_len(struct netlink_sock *nlk, int err,
2160 const struct netlink_ext_ack *extack)
2161{
2162 size_t tlvlen;
2163
2164 if (!extack || !test_bit(NETLINK_F_EXT_ACK, &nlk->flags))
2165 return 0;
2166
2167 tlvlen = 0;
2168 if (extack->_msg)
2169 tlvlen += nla_total_size(payload: strlen(extack->_msg) + 1);
2170 if (extack->cookie_len)
2171 tlvlen += nla_total_size(payload: extack->cookie_len);
2172
2173 /* Following attributes are only reported as error (not warning) */
2174 if (!err)
2175 return tlvlen;
2176
2177 if (extack->bad_attr)
2178 tlvlen += nla_total_size(payload: sizeof(u32));
2179 if (extack->policy)
2180 tlvlen += netlink_policy_dump_attr_size_estimate(pt: extack->policy);
2181 if (extack->miss_type)
2182 tlvlen += nla_total_size(payload: sizeof(u32));
2183 if (extack->miss_nest)
2184 tlvlen += nla_total_size(payload: sizeof(u32));
2185
2186 return tlvlen;
2187}
2188
2189static bool nlmsg_check_in_payload(const struct nlmsghdr *nlh, const void *addr)
2190{
2191 return !WARN_ON(addr < nlmsg_data(nlh) ||
2192 addr - (const void *) nlh >= nlh->nlmsg_len);
2193}
2194
2195static void
2196netlink_ack_tlv_fill(struct sk_buff *skb, const struct nlmsghdr *nlh, int err,
2197 const struct netlink_ext_ack *extack)
2198{
2199 if (extack->_msg)
2200 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg));
2201 if (extack->cookie_len)
2202 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
2203 extack->cookie_len, extack->cookie));
2204
2205 if (!err)
2206 return;
2207
2208 if (extack->bad_attr && nlmsg_check_in_payload(nlh, addr: extack->bad_attr))
2209 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
2210 (u8 *)extack->bad_attr - (const u8 *)nlh));
2211 if (extack->policy)
2212 netlink_policy_dump_write_attr(skb, pt: extack->policy,
2213 nestattr: NLMSGERR_ATTR_POLICY);
2214 if (extack->miss_type)
2215 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_TYPE,
2216 extack->miss_type));
2217 if (extack->miss_nest && nlmsg_check_in_payload(nlh, addr: extack->miss_nest))
2218 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_NEST,
2219 (u8 *)extack->miss_nest - (const u8 *)nlh));
2220}
2221
2222/*
2223 * It looks a bit ugly.
2224 * It would be better to create kernel thread.
2225 */
2226
2227static int netlink_dump_done(struct netlink_sock *nlk, struct sk_buff *skb,
2228 struct netlink_callback *cb,
2229 struct netlink_ext_ack *extack)
2230{
2231 struct nlmsghdr *nlh;
2232 size_t extack_len;
2233
2234 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, payload: sizeof(nlk->dump_done_errno),
2235 NLM_F_MULTI | cb->answer_flags);
2236 if (WARN_ON(!nlh))
2237 return -ENOBUFS;
2238
2239 nl_dump_check_consistent(cb, nlh);
2240 memcpy(to: nlmsg_data(nlh), from: &nlk->dump_done_errno, len: sizeof(nlk->dump_done_errno));
2241
2242 extack_len = netlink_ack_tlv_len(nlk, err: nlk->dump_done_errno, extack);
2243 if (extack_len) {
2244 nlh->nlmsg_flags |= NLM_F_ACK_TLVS;
2245 if (skb_tailroom(skb) >= extack_len) {
2246 netlink_ack_tlv_fill(skb, nlh: cb->nlh,
2247 err: nlk->dump_done_errno, extack);
2248 nlmsg_end(skb, nlh);
2249 }
2250 }
2251
2252 return 0;
2253}
2254
2255static int netlink_dump(struct sock *sk, bool lock_taken)
2256{
2257 struct netlink_sock *nlk = nlk_sk(sk);
2258 struct netlink_ext_ack extack = {};
2259 struct netlink_callback *cb;
2260 struct sk_buff *skb = NULL;
2261 unsigned int rmem, rcvbuf;
2262 size_t max_recvmsg_len;
2263 struct module *module;
2264 int err = -ENOBUFS;
2265 int alloc_min_size;
2266 int alloc_size;
2267
2268 if (!lock_taken)
2269 mutex_lock(lock: &nlk->nl_cb_mutex);
2270 if (!nlk->cb_running) {
2271 err = -EINVAL;
2272 goto errout_skb;
2273 }
2274
2275 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2276 * required, but it makes sense to _attempt_ a 32KiB allocation
2277 * to reduce number of system calls on dump operations, if user
2278 * ever provided a big enough buffer.
2279 */
2280 cb = &nlk->cb;
2281 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2282
2283 max_recvmsg_len = READ_ONCE(nlk->max_recvmsg_len);
2284 if (alloc_min_size < max_recvmsg_len) {
2285 alloc_size = max_recvmsg_len;
2286 skb = alloc_skb(size: alloc_size,
2287 priority: (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) |
2288 __GFP_NOWARN | __GFP_NORETRY);
2289 }
2290 if (!skb) {
2291 alloc_size = alloc_min_size;
2292 skb = alloc_skb(size: alloc_size, GFP_KERNEL);
2293 }
2294 if (!skb)
2295 goto errout_skb;
2296
2297 rcvbuf = READ_ONCE(sk->sk_rcvbuf);
2298 rmem = atomic_add_return(i: skb->truesize, v: &sk->sk_rmem_alloc);
2299 if (rmem != skb->truesize && rmem >= rcvbuf) {
2300 atomic_sub(i: skb->truesize, v: &sk->sk_rmem_alloc);
2301 goto errout_skb;
2302 }
2303
2304 /* Trim skb to allocated size. User is expected to provide buffer as
2305 * large as max(min_dump_alloc, 32KiB (max_recvmsg_len capped at
2306 * netlink_recvmsg())). dump will pack as many smaller messages as
2307 * could fit within the allocated skb. skb is typically allocated
2308 * with larger space than required (could be as much as near 2x the
2309 * requested size with align to next power of 2 approach). Allowing
2310 * dump to use the excess space makes it difficult for a user to have a
2311 * reasonable static buffer based on the expected largest dump of a
2312 * single netdev. The outcome is MSG_TRUNC error.
2313 */
2314 skb_reserve(skb, len: skb_tailroom(skb) - alloc_size);
2315
2316 /* Make sure malicious BPF programs can not read unitialized memory
2317 * from skb->head -> skb->data
2318 */
2319 skb_reset_network_header(skb);
2320 skb_reset_mac_header(skb);
2321
2322 netlink_skb_set_owner_r(skb, sk);
2323
2324 if (nlk->dump_done_errno > 0) {
2325 cb->extack = &extack;
2326
2327 nlk->dump_done_errno = cb->dump(skb, cb);
2328
2329 /* EMSGSIZE plus something already in the skb means
2330 * that there's more to dump but current skb has filled up.
2331 * If the callback really wants to return EMSGSIZE to user space
2332 * it needs to do so again, on the next cb->dump() call,
2333 * without putting data in the skb.
2334 */
2335 if (nlk->dump_done_errno == -EMSGSIZE && skb->len)
2336 nlk->dump_done_errno = skb->len;
2337
2338 cb->extack = NULL;
2339 }
2340
2341 if (nlk->dump_done_errno > 0 ||
2342 skb_tailroom(skb) < nlmsg_total_size(payload: sizeof(nlk->dump_done_errno))) {
2343 mutex_unlock(lock: &nlk->nl_cb_mutex);
2344
2345 if (sk_filter(sk, skb))
2346 kfree_skb(skb);
2347 else
2348 __netlink_sendskb(sk, skb);
2349 return 0;
2350 }
2351
2352 if (netlink_dump_done(nlk, skb, cb, extack: &extack))
2353 goto errout_skb;
2354
2355#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
2356 /* frag_list skb's data is used for compat tasks
2357 * and the regular skb's data for normal (non-compat) tasks.
2358 * See netlink_recvmsg().
2359 */
2360 if (unlikely(skb_shinfo(skb)->frag_list)) {
2361 if (netlink_dump_done(nlk, skb_shinfo(skb)->frag_list, cb, &extack))
2362 goto errout_skb;
2363 }
2364#endif
2365
2366 if (sk_filter(sk, skb))
2367 kfree_skb(skb);
2368 else
2369 __netlink_sendskb(sk, skb);
2370
2371 if (cb->done)
2372 cb->done(cb);
2373
2374 WRITE_ONCE(nlk->cb_running, false);
2375 module = cb->module;
2376 skb = cb->skb;
2377 mutex_unlock(lock: &nlk->nl_cb_mutex);
2378 module_put(module);
2379 consume_skb(skb);
2380 return 0;
2381
2382errout_skb:
2383 mutex_unlock(lock: &nlk->nl_cb_mutex);
2384 kfree_skb(skb);
2385 return err;
2386}
2387
2388int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2389 const struct nlmsghdr *nlh,
2390 struct netlink_dump_control *control)
2391{
2392 struct netlink_callback *cb;
2393 struct netlink_sock *nlk;
2394 struct sock *sk;
2395 int ret;
2396
2397 refcount_inc(r: &skb->users);
2398
2399 sk = netlink_lookup(net: sock_net(sk: ssk), protocol: ssk->sk_protocol, NETLINK_CB(skb).portid);
2400 if (sk == NULL) {
2401 ret = -ECONNREFUSED;
2402 goto error_free;
2403 }
2404
2405 nlk = nlk_sk(sk);
2406 mutex_lock(lock: &nlk->nl_cb_mutex);
2407 /* A dump is in progress... */
2408 if (nlk->cb_running) {
2409 ret = -EBUSY;
2410 goto error_unlock;
2411 }
2412 /* add reference of module which cb->dump belongs to */
2413 if (!try_module_get(module: control->module)) {
2414 ret = -EPROTONOSUPPORT;
2415 goto error_unlock;
2416 }
2417
2418 cb = &nlk->cb;
2419 memset(s: cb, c: 0, n: sizeof(*cb));
2420 cb->dump = control->dump;
2421 cb->done = control->done;
2422 cb->nlh = nlh;
2423 cb->data = control->data;
2424 cb->module = control->module;
2425 cb->min_dump_alloc = control->min_dump_alloc;
2426 cb->flags = control->flags;
2427 cb->skb = skb;
2428
2429 cb->strict_check = nlk_test_bit(STRICT_CHK, NETLINK_CB(skb).sk);
2430
2431 if (control->start) {
2432 cb->extack = control->extack;
2433 ret = control->start(cb);
2434 cb->extack = NULL;
2435 if (ret)
2436 goto error_put;
2437 }
2438
2439 WRITE_ONCE(nlk->cb_running, true);
2440 nlk->dump_done_errno = INT_MAX;
2441
2442 ret = netlink_dump(sk, lock_taken: true);
2443
2444 sock_put(sk);
2445
2446 if (ret)
2447 return ret;
2448
2449 /* We successfully started a dump, by returning -EINTR we
2450 * signal not to send ACK even if it was requested.
2451 */
2452 return -EINTR;
2453
2454error_put:
2455 module_put(module: control->module);
2456error_unlock:
2457 sock_put(sk);
2458 mutex_unlock(lock: &nlk->nl_cb_mutex);
2459error_free:
2460 kfree_skb(skb);
2461 return ret;
2462}
2463EXPORT_SYMBOL(__netlink_dump_start);
2464
2465void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
2466 const struct netlink_ext_ack *extack)
2467{
2468 struct sk_buff *skb;
2469 struct nlmsghdr *rep;
2470 struct nlmsgerr *errmsg;
2471 size_t payload = sizeof(*errmsg);
2472 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2473 unsigned int flags = 0;
2474 size_t tlvlen;
2475
2476 /* Error messages get the original request appended, unless the user
2477 * requests to cap the error message, and get extra error data if
2478 * requested.
2479 */
2480 if (err && !test_bit(NETLINK_F_CAP_ACK, &nlk->flags))
2481 payload += nlmsg_len(nlh);
2482 else
2483 flags |= NLM_F_CAPPED;
2484
2485 tlvlen = netlink_ack_tlv_len(nlk, err, extack);
2486 if (tlvlen)
2487 flags |= NLM_F_ACK_TLVS;
2488
2489 skb = nlmsg_new(payload: payload + tlvlen, GFP_KERNEL);
2490 if (!skb)
2491 goto err_skb;
2492
2493 rep = nlmsg_put(skb, NETLINK_CB(in_skb).portid, seq: nlh->nlmsg_seq,
2494 NLMSG_ERROR, payload: sizeof(*errmsg), flags);
2495 if (!rep)
2496 goto err_bad_put;
2497 errmsg = nlmsg_data(nlh: rep);
2498 errmsg->error = err;
2499 errmsg->msg = *nlh;
2500
2501 if (!(flags & NLM_F_CAPPED)) {
2502 if (!nlmsg_append(skb, size: nlmsg_len(nlh)))
2503 goto err_bad_put;
2504
2505 memcpy(to: nlmsg_data(nlh: &errmsg->msg), from: nlmsg_data(nlh),
2506 len: nlmsg_len(nlh));
2507 }
2508
2509 if (tlvlen)
2510 netlink_ack_tlv_fill(skb, nlh, err, extack);
2511
2512 nlmsg_end(skb, nlh: rep);
2513
2514 nlmsg_unicast(sk: in_skb->sk, skb, NETLINK_CB(in_skb).portid);
2515
2516 return;
2517
2518err_bad_put:
2519 nlmsg_free(skb);
2520err_skb:
2521 WRITE_ONCE(NETLINK_CB(in_skb).sk->sk_err, ENOBUFS);
2522 sk_error_report(NETLINK_CB(in_skb).sk);
2523}
2524EXPORT_SYMBOL(netlink_ack);
2525
2526int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2527 struct nlmsghdr *,
2528 struct netlink_ext_ack *))
2529{
2530 struct netlink_ext_ack extack;
2531 struct nlmsghdr *nlh;
2532 int err;
2533
2534 while (skb->len >= nlmsg_total_size(payload: 0)) {
2535 int msglen;
2536
2537 memset(s: &extack, c: 0, n: sizeof(extack));
2538 nlh = nlmsg_hdr(skb);
2539 err = 0;
2540
2541 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2542 return 0;
2543
2544 /* Only requests are handled by the kernel */
2545 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2546 goto ack;
2547
2548 /* Skip control messages */
2549 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2550 goto ack;
2551
2552 err = cb(skb, nlh, &extack);
2553 if (err == -EINTR)
2554 goto skip;
2555
2556ack:
2557 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2558 netlink_ack(skb, nlh, err, &extack);
2559
2560skip:
2561 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2562 if (msglen > skb->len)
2563 msglen = skb->len;
2564 skb_pull(skb, len: msglen);
2565 }
2566
2567 return 0;
2568}
2569EXPORT_SYMBOL(netlink_rcv_skb);
2570
2571/**
2572 * nlmsg_notify - send a notification netlink message
2573 * @sk: netlink socket to use
2574 * @skb: notification message
2575 * @portid: destination netlink portid for reports or 0
2576 * @group: destination multicast group or 0
2577 * @report: 1 to report back, 0 to disable
2578 * @flags: allocation flags
2579 */
2580int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2581 unsigned int group, int report, gfp_t flags)
2582{
2583 int err = 0;
2584
2585 if (group) {
2586 int exclude_portid = 0;
2587
2588 if (report) {
2589 refcount_inc(r: &skb->users);
2590 exclude_portid = portid;
2591 }
2592
2593 /* errors reported via destination sk->sk_err, but propagate
2594 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2595 err = nlmsg_multicast(sk, skb, portid: exclude_portid, group, flags);
2596 if (err == -ESRCH)
2597 err = 0;
2598 }
2599
2600 if (report) {
2601 int err2;
2602
2603 err2 = nlmsg_unicast(sk, skb, portid);
2604 if (!err)
2605 err = err2;
2606 }
2607
2608 return err;
2609}
2610EXPORT_SYMBOL(nlmsg_notify);
2611
2612#ifdef CONFIG_PROC_FS
2613struct nl_seq_iter {
2614 struct seq_net_private p;
2615 struct rhashtable_iter hti;
2616 int link;
2617};
2618
2619static void netlink_walk_start(struct nl_seq_iter *iter)
2620{
2621 rhashtable_walk_enter(ht: &nl_table[iter->link].hash, iter: &iter->hti);
2622 rhashtable_walk_start(iter: &iter->hti);
2623}
2624
2625static void netlink_walk_stop(struct nl_seq_iter *iter)
2626{
2627 rhashtable_walk_stop(iter: &iter->hti);
2628 rhashtable_walk_exit(iter: &iter->hti);
2629}
2630
2631static void *__netlink_seq_next(struct seq_file *seq)
2632{
2633 struct nl_seq_iter *iter = seq->private;
2634 struct netlink_sock *nlk;
2635
2636 do {
2637 for (;;) {
2638 nlk = rhashtable_walk_next(iter: &iter->hti);
2639
2640 if (IS_ERR(ptr: nlk)) {
2641 if (PTR_ERR(ptr: nlk) == -EAGAIN)
2642 continue;
2643
2644 return nlk;
2645 }
2646
2647 if (nlk)
2648 break;
2649
2650 netlink_walk_stop(iter);
2651 if (++iter->link >= MAX_LINKS)
2652 return NULL;
2653
2654 netlink_walk_start(iter);
2655 }
2656 } while (sock_net(sk: &nlk->sk) != seq_file_net(seq));
2657
2658 return nlk;
2659}
2660
2661static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2662 __acquires(RCU)
2663{
2664 struct nl_seq_iter *iter = seq->private;
2665 void *obj = SEQ_START_TOKEN;
2666 loff_t pos;
2667
2668 iter->link = 0;
2669
2670 netlink_walk_start(iter);
2671
2672 for (pos = *posp; pos && obj && !IS_ERR(ptr: obj); pos--)
2673 obj = __netlink_seq_next(seq);
2674
2675 return obj;
2676}
2677
2678static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2679{
2680 ++*pos;
2681 return __netlink_seq_next(seq);
2682}
2683
2684static void netlink_native_seq_stop(struct seq_file *seq, void *v)
2685{
2686 struct nl_seq_iter *iter = seq->private;
2687
2688 if (iter->link >= MAX_LINKS)
2689 return;
2690
2691 netlink_walk_stop(iter);
2692}
2693
2694
2695static int netlink_native_seq_show(struct seq_file *seq, void *v)
2696{
2697 if (v == SEQ_START_TOKEN) {
2698 seq_puts(m: seq,
2699 s: "sk Eth Pid Groups "
2700 "Rmem Wmem Dump Locks Drops Inode\n");
2701 } else {
2702 struct sock *s = v;
2703 struct netlink_sock *nlk = nlk_sk(sk: s);
2704
2705 seq_printf(m: seq, fmt: "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8u %-8lu\n",
2706 s,
2707 s->sk_protocol,
2708 nlk->portid,
2709 nlk->groups ? (u32)nlk->groups[0] : 0,
2710 sk_rmem_alloc_get(sk: s),
2711 sk_wmem_alloc_get(sk: s),
2712 READ_ONCE(nlk->cb_running),
2713 refcount_read(r: &s->sk_refcnt),
2714 sk_drops_read(sk: s),
2715 sock_i_ino(sk: s)
2716 );
2717
2718 }
2719 return 0;
2720}
2721
2722#ifdef CONFIG_BPF_SYSCALL
2723struct bpf_iter__netlink {
2724 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2725 __bpf_md_ptr(struct netlink_sock *, sk);
2726};
2727
2728DEFINE_BPF_ITER_FUNC(netlink, struct bpf_iter_meta *meta, struct netlink_sock *sk)
2729
2730static int netlink_prog_seq_show(struct bpf_prog *prog,
2731 struct bpf_iter_meta *meta,
2732 void *v)
2733{
2734 struct bpf_iter__netlink ctx;
2735
2736 meta->seq_num--; /* skip SEQ_START_TOKEN */
2737 ctx.meta = meta;
2738 ctx.sk = nlk_sk((struct sock *)v);
2739 return bpf_iter_run_prog(prog, &ctx);
2740}
2741
2742static int netlink_seq_show(struct seq_file *seq, void *v)
2743{
2744 struct bpf_iter_meta meta;
2745 struct bpf_prog *prog;
2746
2747 meta.seq = seq;
2748 prog = bpf_iter_get_info(&meta, false);
2749 if (!prog)
2750 return netlink_native_seq_show(seq, v);
2751
2752 if (v != SEQ_START_TOKEN)
2753 return netlink_prog_seq_show(prog, &meta, v);
2754
2755 return 0;
2756}
2757
2758static void netlink_seq_stop(struct seq_file *seq, void *v)
2759{
2760 struct bpf_iter_meta meta;
2761 struct bpf_prog *prog;
2762
2763 if (!v) {
2764 meta.seq = seq;
2765 prog = bpf_iter_get_info(&meta, true);
2766 if (prog)
2767 (void)netlink_prog_seq_show(prog, &meta, v);
2768 }
2769
2770 netlink_native_seq_stop(seq, v);
2771}
2772#else
2773static int netlink_seq_show(struct seq_file *seq, void *v)
2774{
2775 return netlink_native_seq_show(seq, v);
2776}
2777
2778static void netlink_seq_stop(struct seq_file *seq, void *v)
2779{
2780 netlink_native_seq_stop(seq, v);
2781}
2782#endif
2783
2784static const struct seq_operations netlink_seq_ops = {
2785 .start = netlink_seq_start,
2786 .next = netlink_seq_next,
2787 .stop = netlink_seq_stop,
2788 .show = netlink_seq_show,
2789};
2790#endif
2791
2792int netlink_register_notifier(struct notifier_block *nb)
2793{
2794 return blocking_notifier_chain_register(nh: &netlink_chain, nb);
2795}
2796EXPORT_SYMBOL(netlink_register_notifier);
2797
2798int netlink_unregister_notifier(struct notifier_block *nb)
2799{
2800 return blocking_notifier_chain_unregister(nh: &netlink_chain, nb);
2801}
2802EXPORT_SYMBOL(netlink_unregister_notifier);
2803
2804static const struct proto_ops netlink_ops = {
2805 .family = PF_NETLINK,
2806 .owner = THIS_MODULE,
2807 .release = netlink_release,
2808 .bind = netlink_bind,
2809 .connect = netlink_connect,
2810 .socketpair = sock_no_socketpair,
2811 .accept = sock_no_accept,
2812 .getname = netlink_getname,
2813 .poll = datagram_poll,
2814 .ioctl = netlink_ioctl,
2815 .listen = sock_no_listen,
2816 .shutdown = sock_no_shutdown,
2817 .setsockopt = netlink_setsockopt,
2818 .getsockopt = netlink_getsockopt,
2819 .sendmsg = netlink_sendmsg,
2820 .recvmsg = netlink_recvmsg,
2821 .mmap = sock_no_mmap,
2822};
2823
2824static const struct net_proto_family netlink_family_ops = {
2825 .family = PF_NETLINK,
2826 .create = netlink_create,
2827 .owner = THIS_MODULE, /* for consistency 8) */
2828};
2829
2830static int __net_init netlink_net_init(struct net *net)
2831{
2832#ifdef CONFIG_PROC_FS
2833 if (!proc_create_net("netlink", 0, net->proc_net, &netlink_seq_ops,
2834 sizeof(struct nl_seq_iter)))
2835 return -ENOMEM;
2836#endif
2837 return 0;
2838}
2839
2840static void __net_exit netlink_net_exit(struct net *net)
2841{
2842#ifdef CONFIG_PROC_FS
2843 remove_proc_entry("netlink", net->proc_net);
2844#endif
2845}
2846
2847static void __init netlink_add_usersock_entry(void)
2848{
2849 struct listeners *listeners;
2850 int groups = 32;
2851
2852 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2853 if (!listeners)
2854 panic(fmt: "netlink_add_usersock_entry: Cannot allocate listeners\n");
2855
2856 netlink_table_grab();
2857
2858 nl_table[NETLINK_USERSOCK].groups = groups;
2859 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2860 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2861 nl_table[NETLINK_USERSOCK].registered = 1;
2862 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2863
2864 netlink_table_ungrab();
2865}
2866
2867static struct pernet_operations __net_initdata netlink_net_ops = {
2868 .init = netlink_net_init,
2869 .exit = netlink_net_exit,
2870};
2871
2872static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2873{
2874 const struct netlink_sock *nlk = data;
2875 struct netlink_compare_arg arg;
2876
2877 netlink_compare_arg_init(arg: &arg, net: sock_net(sk: &nlk->sk), portid: nlk->portid);
2878 return jhash2(k: (u32 *)&arg, netlink_compare_arg_len / sizeof(u32), initval: seed);
2879}
2880
2881static const struct rhashtable_params netlink_rhashtable_params = {
2882 .head_offset = offsetof(struct netlink_sock, node),
2883 .key_len = netlink_compare_arg_len,
2884 .obj_hashfn = netlink_hash,
2885 .obj_cmpfn = netlink_compare,
2886 .automatic_shrinking = true,
2887};
2888
2889#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2890BTF_ID_LIST_SINGLE(btf_netlink_sock_id, struct, netlink_sock)
2891
2892static const struct bpf_iter_seq_info netlink_seq_info = {
2893 .seq_ops = &netlink_seq_ops,
2894 .init_seq_private = bpf_iter_init_seq_net,
2895 .fini_seq_private = bpf_iter_fini_seq_net,
2896 .seq_priv_size = sizeof(struct nl_seq_iter),
2897};
2898
2899static struct bpf_iter_reg netlink_reg_info = {
2900 .target = "netlink",
2901 .ctx_arg_info_size = 1,
2902 .ctx_arg_info = {
2903 { offsetof(struct bpf_iter__netlink, sk),
2904 PTR_TO_BTF_ID_OR_NULL },
2905 },
2906 .seq_info = &netlink_seq_info,
2907};
2908
2909static int __init bpf_iter_register(void)
2910{
2911 netlink_reg_info.ctx_arg_info[0].btf_id = *btf_netlink_sock_id;
2912 return bpf_iter_reg_target(&netlink_reg_info);
2913}
2914#endif
2915
2916static int __init netlink_proto_init(void)
2917{
2918 int i;
2919 int err = proto_register(prot: &netlink_proto, alloc_slab: 0);
2920
2921 if (err != 0)
2922 goto out;
2923
2924#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2925 err = bpf_iter_register();
2926 if (err)
2927 goto out;
2928#endif
2929
2930 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof_field(struct sk_buff, cb));
2931
2932 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2933 if (!nl_table)
2934 goto panic;
2935
2936 for (i = 0; i < MAX_LINKS; i++) {
2937 if (rhashtable_init(&nl_table[i].hash,
2938 &netlink_rhashtable_params) < 0)
2939 goto panic;
2940 }
2941
2942 netlink_add_usersock_entry();
2943
2944 sock_register(fam: &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();
2949out:
2950 return err;
2951panic:
2952 panic(fmt: "netlink_init: Cannot allocate nl_table\n");
2953}
2954
2955core_initcall(netlink_proto_init);
2956